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WO2025074861A1 - Élément optique et dispositif de projection d'image - Google Patents

Élément optique et dispositif de projection d'image Download PDF

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Publication number
WO2025074861A1
WO2025074861A1 PCT/JP2024/033277 JP2024033277W WO2025074861A1 WO 2025074861 A1 WO2025074861 A1 WO 2025074861A1 JP 2024033277 W JP2024033277 W JP 2024033277W WO 2025074861 A1 WO2025074861 A1 WO 2025074861A1
Authority
WO
WIPO (PCT)
Prior art keywords
image
light
image light
mirror
far
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2024/033277
Other languages
English (en)
Japanese (ja)
Inventor
憂士 森本
雅大 遠藤
一臣 村上
一嘉 小澤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koito Manufacturing Co Ltd
Original Assignee
Koito Manufacturing Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from JP2023171710A external-priority patent/JP2025062543A/ja
Priority claimed from JP2023188973A external-priority patent/JP2025077059A/ja
Priority claimed from JP2023188972A external-priority patent/JP2025077058A/ja
Priority claimed from JP2023199454A external-priority patent/JP2025085522A/ja
Application filed by Koito Manufacturing Co Ltd filed Critical Koito Manufacturing Co Ltd
Publication of WO2025074861A1 publication Critical patent/WO2025074861A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
    • B60K35/00—Instruments specially adapted for vehicles; Arrangement of instruments in or on vehicles
    • B60K35/20—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor
    • B60K35/21—Output arrangements, i.e. from vehicle to user, associated with vehicle functions or specially adapted therefor using visual output, e.g. blinking lights or matrix displays
    • B60K35/23—Head-up displays [HUD]
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
    • G02B27/01—Head-up displays
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N5/00—Details of television systems
    • H04N5/64—Constructional details of receivers, e.g. cabinets or dust covers

Definitions

  • This disclosure relates to optical elements and image projection devices, and in particular to optical elements and image projection devices that project a projected image onto a display unit for displaying a virtual image.
  • dashboards that light up icons have been used as devices to display various types of information inside vehicles. As the amount of information to be displayed increases, it has also been proposed to embed an image display device in the dashboard or to configure the entire dashboard from an image display device.
  • HUD head-up display
  • image light is projected from an image projection unit onto the vehicle's windshield (display unit), and the driver can visually recognize the image light reflected by the windshield superimposed on the background in front of the vehicle. It has also been proposed to project multiple beams of image light and form multiple virtual images at different distances from the windshield.
  • a reflecting prism or the like can be used as an optical component for splitting the image light, but in order to split the image light emitted from a large display area, the reflecting prism needs to be made thick, which poses problems in terms of formability and weight reduction.
  • the refractive index of the material composing the reflecting prism is higher than that of air, there are restrictions in terms of the path difference of the light propagating inside the reflecting prism and the angle of the reflecting surface, resulting in a problem of low design freedom.
  • aberration will occur in the projected virtual image depending on the angle at which the image light is incident on the reflecting surface, which also poses the problem of reduced visibility of the virtual image.
  • conventional image projection devices reflect image light using a free-form mirror and a windshield WS to form a virtual image in space, which causes aberrations that misalign the paths of the image light entering the left and right eyes, resulting in vertical and horizontal parallax and reduced visibility of the virtual image.
  • One of the objectives of this disclosure is to provide an optical component and an image projection device that can appropriately split multiple image lights, while enabling weight reduction and improved design freedom.
  • One of the objectives of this disclosure is to provide an image projection device that can improve the accuracy of aberration correction and improve the visibility of the virtual image that is formed.
  • One of the objectives of this disclosure is to provide an optical component and an image projection device that can achieve weight reduction and improved design freedom.
  • the optical member of the present disclosure has a first reflecting surface, a second reflecting surface arranged opposite the first reflecting surface, a gap portion provided between the first reflecting surface and the second reflecting surface, a first holding portion that holds the first reflecting surface, a second holding portion that holds the second reflecting surface, and a connecting portion that is formed integrally with the first holding portion and the second holding portion and connects them together.
  • the first holding portion holds the first reflective surface
  • the second holding portion holds the second reflective surface
  • a connecting portion connecting the two is integrally formed, and a gap is provided between the first and second reflective surfaces, so that the distance and relative positional relationship between the first and second reflective surfaces is kept constant, and multiple image light beams can be appropriately branched, making it possible to reduce weight and improve design freedom.
  • the image projection device disclosed herein is an image projection device that projects image light onto a display unit for displaying a virtual image, and includes an image irradiation unit that irradiates the image light, and a projection optical unit that irradiates the image light onto the display unit, the image irradiation unit having the optical member described above, the image irradiation unit irradiates near image light from a near display area and far image light from a far display area, the far image light is reflected by the first reflecting surface and the second reflecting surface to reach the projection optical unit, and the near image light passes through the gap to reach the projection optical unit.
  • the image projection device disclosed herein is an image projection device that projects image light onto a display unit for displaying a virtual image, and includes an image irradiation unit that irradiates the image light, a primary mirror that reflects the image light incident from the image irradiation unit, and a secondary mirror that reflects the image light incident from the primary mirror, and the reflective surface of the primary mirror has a saddle shape that is concave in a first direction and convex in a second direction.
  • the reflective surface of the primary mirror is saddle-shaped, concave in a first direction and convex in a second direction, and the image light reflected by the primary mirror is reflected by the secondary mirror, improving the accuracy of aberration correction and improving the visibility of the virtual image that is formed.
  • the image projection device disclosed herein is an image projection device that projects image light onto a display unit for displaying a virtual image, and includes an image display unit that irradiates near image light from a near display area and far image light from a far display area, a first plane mirror that reflects the far image light, a second plane mirror that reflects the far image light reflected by the first plane mirror, and a projection optical unit that irradiates the near image light incident from the near display area and the far image light incident from the second plane mirror onto the display unit.
  • the far-distance image light irradiated from the far-distance display area is reflected by the first and second plane mirrors, near-distance image light is irradiated from the near-distance display area, and the far-distance image light and near-distance image light are irradiated from the projection optical unit to the display unit, thereby allowing for appropriate branching of multiple image lights, which makes it possible to reduce weight and improve design freedom.
  • the optical member of the present disclosure has a first portion made of a material that transmits light and has a first reflecting surface, a second portion arranged opposite the first portion and made of a material that transmits the light and has a second reflecting surface, a connecting portion formed integrally with the first portion and the second portion to connect them, and a gap portion provided between the first portion and the second portion and through which at least a portion of the light passes.
  • the first portion, the second portion, and the connecting portion are integrally formed from a light-transmitting material, and a gap is provided between the first portion and the second portion, which allows for weight reduction and improved design freedom.
  • the image projection device disclosed herein is an image projection device that projects image light onto a display unit for displaying a virtual image, and includes the above optical member, an image irradiation unit that irradiates the image light, and a projection optical unit that irradiates the image light onto the display unit, the image irradiation unit irradiates near image light from a near display area and far image light from a far display area, the far image light is reflected by the first reflecting surface and the second reflecting surface to reach the projection optical unit, and the near image light passes through the gap to reach the projection optical unit.
  • the present disclosure provides an optical component and an image projection device that can appropriately split multiple image lights, while achieving weight reduction and improved design freedom.
  • This disclosure provides an image projection device that can improve the accuracy of aberration correction and improve the visibility of the virtual image that is formed.
  • This disclosure provides an optical component and an image projection device that can reduce weight and improve design freedom.
  • FIG. 1A and 1B are schematic diagrams illustrating projection of a virtual image using the image projection device according to the first embodiment.
  • 3 is a schematic diagram showing a configuration example of an image projection unit in the first embodiment.
  • FIG. 4 is a schematic perspective view showing an example of the structure of a mirror holding portion in the first embodiment.
  • FIG. 5A to 5C are schematic cross-sectional views showing an example of the structure of a mirror holding portion in the first embodiment.
  • 5A to 5C are schematic cross-sectional views showing a method of forming a mirror holding portion in the first embodiment.
  • FIG. 11 is a schematic perspective view showing an example of the structure of a mirror holding portion in a modified example of the first embodiment.
  • FIG. 11 is a schematic perspective view showing an example of the structure of a mirror holding portion in a modified example of the first embodiment.
  • FIG. 11 is a schematic top perspective view showing an example of the structure of a mirror holding portion in the second embodiment.
  • FIG. 11 is a schematic bottom perspective view showing an example of the structure of a mirror holding portion in the second embodiment.
  • 10A to 10C are schematic cross-sectional views showing a method of forming a mirror holding portion in the second embodiment.
  • 10A to 10C are schematic cross-sectional views showing a method of forming a mirror holding portion in the second embodiment.
  • FIG. 13 is a schematic top perspective view showing an example of the structure of a mirror holding portion in the third embodiment.
  • FIG. 13 is a schematic bottom perspective view showing an example of the structure of a mirror holding portion in the third embodiment.
  • FIG. 13 is a schematic top perspective view showing an example of the structure of a mirror holding portion in the fourth embodiment.
  • FIG. 13 is a schematic bottom perspective view showing an example of the structure of a mirror holding portion in the fourth embodiment.
  • FIG. 13 is a schematic top perspective view showing an example of the structure of a mirror holding portion in the fifth embodiment.
  • FIG. 13 is a schematic bottom perspective view showing an example of the structure of a mirror holding portion in the fifth embodiment.
  • FIG. 23 is a schematic top perspective view showing an example of the structure of a mirror holding portion in the sixth embodiment.
  • FIG. 13 is a schematic bottom perspective view showing an example of the structure of a mirror holding portion 50 in the sixth embodiment.
  • FIG. 23 is a schematic perspective view illustrating the structure of a primary mirror in the seventh embodiment.
  • FIG. 23 is a schematic horizontal cross-sectional view illustrating the structure of a primary mirror in the seventh embodiment.
  • FIG. 23 is a schematic vertical cross-sectional view illustrating the structure of a primary mirror in the seventh embodiment.
  • FIG. 23 is a schematic diagram showing a configuration example of an image projection unit in the seventh embodiment.
  • 23 is a schematic side view illustrating the positional relationship between the image irradiator, the primary mirror, and the secondary mirror, and the path of the image light in the seventh embodiment.
  • FIG. 23 is a schematic diagram of a top view illustrating the positional relationship between an image irradiator, a primary mirror, and a secondary mirror, and the path of image light in the seventh embodiment.
  • FIG. 1 is a schematic diagram illustrating parallax caused by aberration, showing left-right parallax.
  • 1 is a schematic diagram illustrating parallax caused by aberration, showing vertical parallax.
  • FIG. 23 is a schematic diagram showing a configuration example of an image projection unit in the ninth embodiment.
  • 13 is a schematic perspective view illustrating paths of far-distance image light L1 and near-distance image light L2 irradiated from an image irradiator in the ninth embodiment.
  • FIG. 13A and 13B are schematic diagrams illustrating angles between a first plane mirror and a second plane mirror in an image irradiation unit in the ninth embodiment.
  • FIG. 23A to 23C are schematic diagrams illustrating a configuration example of an image projection unit and angles between a first plane mirror and a second plane mirror in a tenth embodiment.
  • 13 is a schematic diagram illustrating the projection of a virtual image using an image projection device according to an eleventh embodiment.
  • FIG. 13 is a schematic cross-sectional view illustrating an overview of an image projection device according to an eleventh embodiment.
  • FIG. 23 is a schematic cross-sectional view showing an example of the configuration of an optical member in an eleventh embodiment.
  • FIG. 23 is a schematic perspective view showing an example of the configuration of an optical member in an eleventh embodiment.
  • FIG. 23 is a schematic cross-sectional view showing an example of the configuration of an optical member in a twelfth embodiment.
  • FIG. 23 is a schematic cross-sectional view showing an example of the configuration of an optical member in a thirteenth embodiment.
  • FIG. 23 is a schematic cross-sectional view showing an example of the configuration of an optical member in a fourteenth embodiment.
  • 23A to 23C are schematic cross-sectional views showing examples of the configuration of an optical member in a fifteenth embodiment.
  • First Embodiment 1 is a schematic diagram for explaining the projection of virtual images P1 and P2 using an image projection device 100 according to the present embodiment.
  • the image projection device 100 includes an image projection unit 10, a primary mirror 20, and a secondary mirror 30.
  • the direction perpendicular to the paper surface is the x-axis direction
  • the up-down direction is the y-axis direction
  • the left-right direction is the z-axis direction.
  • the x-axis direction corresponds to the left-right direction (width direction) of the vehicle on which the image projection device 100 is mounted
  • the y-axis direction corresponds to the up-down direction (vertical direction)
  • the z-axis direction corresponds to the front-rear direction.
  • image light projected from the image projection device 100 is reflected by the windshield (display unit) WS and irradiated to the driver's viewpoint.
  • the driver visually recognizes virtual images P1 and P2 formed on an extension (in the direction of the dashed line) of the optical path along which the image light entered.
  • the image projection device 100 projects image display light to form two virtual images P1 and P2, but the number of virtual images is not limited.
  • the image projection unit 10 irradiates image light for far distances and image light for near distances, which are respectively formed as virtual images P1 and P2.
  • the dashed line in FIG. 1 shows a schematic path (reference light ray) of the center position of the image light for far distances
  • the dashed line shows a schematic path (reference light ray) of the center position of the image light for near distances.
  • the driver's line of sight and viewpoint distance tend to change depending on the traveling speed of the vehicle, and as the vehicle speed increases, the driver's line of sight and viewpoint distance tend to move farther away.
  • the image light for near distances in a low-speed range such as when the vehicle is traveling on a general road
  • displaying the image light for far distances in a high-speed range such as when the vehicle is traveling on a highway
  • the information displayed by the far image and the near image may be switched.
  • the far image projected by the image light for far distances may be auxiliary information related to driving, such as an image for calling attention or emergency information.
  • Near images projected using near image light include speed and volume indicators, direction guides, etc.
  • the far-field image light and near-field image light irradiated from the image irradiation unit 10 are reflected by the primary mirror 20, the secondary mirror 30, and the windshield WS to reach the viewpoint 40.
  • the trajectory of the light reaching the viewpoint 40 from the direction in which the virtual images P1 and P2 are viewed is taken as the reference ray.
  • this reference ray can be considered to be substantially the same as the trajectory of the light irradiated from the center of the effective area from which the light is emitted in the image irradiation unit 10 when it reaches the viewpoint 40.
  • the actual image light is irradiated from the image irradiation unit 10 over a specified area, and the light beam spreads from each position on the display surface, and is focused or expanded by the optical power of the reflecting surfaces of the primary mirror 20 and the secondary mirror 30. Therefore, the reference ray shown in FIG. 1 does not indicate the path along which the irradiated light travels in the entire area of the image irradiation unit 10.
  • the image irradiation unit 10 is a part that irradiates image light containing image information in response to a signal containing image information being supplied from an information processing unit (not shown). Details of the image irradiation unit 10 will be described later.
  • the image light irradiated from the image irradiation unit 10 is incident on the primary mirror 20.
  • the specific configuration of the image irradiation unit 10 is not limited, and any conventionally known device such as a liquid crystal display device, an organic EL display device, or a combination of a laser light source and a light modulation element can be used. In the example shown in Figure 1, a liquid crystal display device is used that irradiates light from a light emitting diode (LED: Light Emitting Diode) from the rear side.
  • LED Light Emitting Diode
  • the primary mirror 20 is an optical member on which the image light irradiated from the image irradiation unit 10 is incident and reflected in the direction of the secondary mirror 30.
  • the primary mirror 20 is a free-form mirror with the optical design required to project the image light as virtual images P1 and P2.
  • the reflective surface of the primary mirror 20 will be described in detail later, but it has a saddle shape that is concave in the y-axis direction (short side direction, which is the height direction, the first direction) and convex in the x-axis direction (long side direction, which is the width direction, the second direction). Therefore, the reflective surface of the primary mirror 20 gives the image light positive optical power in the height direction and negative optical power in the width direction.
  • the reflective surface of the primary mirror 20 is set so that only the y-axis component forms an intermediate image before reaching the secondary mirror 30.
  • the secondary mirror 30 is an optical component that receives the image light reflected by the primary mirror 20 and reflects it in the direction of the windshield WS.
  • the secondary mirror 30 is a free-form mirror with a concave shape optically designed to project the image light as virtual images P1 and P2.
  • the reflective surface of the secondary mirror 30 has different focal lengths for the x-axis component and the y-axis component in the plane, and is set so that the x-axis component and the y-axis component of the irradiated light are imaged at the same position after reflection by the secondary mirror 30.
  • the combination of the primary mirror 20 and the secondary mirror 30 constitutes the projection optical unit in this disclosure, in order to irradiate the near image light and the far image light to the windshield WS.
  • the windshield WS is provided in front of the driver's seat of the vehicle, and on the inside surface of the vehicle, it functions as an optical member that reflects the image light incident from the secondary mirror 30 toward the viewpoint 40, and transmits light from outside the vehicle toward the viewpoint 40. Therefore, the windshield WS corresponds to the display unit in this disclosure.
  • the windshield WS is used as the display unit, but a combiner may be provided as a display unit separate from the windshield WS, and light from the secondary mirror 30 may be reflected toward the viewpoint 40.
  • the display unit is not limited to being located in front of the vehicle, and may be located to the side or rear as long as it projects an image toward the passenger's viewpoint 40.
  • the viewpoint 40 is the eye (eyebox) of the driver or passenger of the vehicle, and the driver or passenger visually recognizes the formed virtual images P1 and P2 as the image light enters the eyebox and reaches the retina.
  • the virtual images P1 and P2 are displayed as if they were formed in space when the image light reflected by the windshield WS reaches the viewpoint (eyebox) 40 of the driver or other person.
  • the position at which the virtual images P1 and P2 are formed is determined by the spread angle of the light irradiated from the image irradiation unit 10 as it travels toward the viewpoint 40 after being reflected by the primary mirror 20 and secondary mirror 30.
  • the driver or passenger at the viewpoint 40 recognizes that the virtual images P1 and P2 exist at an imaging position farther away than the windshield WS.
  • FIG. 2 is a schematic diagram showing an example of the configuration of the image projection unit 10.
  • the image projection unit 10 includes a light source unit 11, an image display unit 12, a first plane mirror 13, a second plane mirror 14, and a mirror holding unit 50.
  • the image display unit 12 also includes a far display area 12a and a near display area 12b.
  • the dashed arrow in FIG. 2 typically shows the path (reference ray) of the center position of the far image light L1, and the dashed arrow typically shows the path (reference ray) of the center position of the near image light L2.
  • the light source unit 11 is a part that irradiates the image display unit 12 with irradiation light.
  • the light source unit 11 is disposed on the rear side of the transmissive image display unit 12, and the irradiation light passes through the image display unit 12; however, a reflective image display unit 12 may be used to irradiate the irradiation light from the display surface side.
  • the specific configuration of the light source unit 11 is not limited, and a light-emitting diode or a laser light source may be used.
  • an organic EL display device is used as the image display unit 12, the light source unit 11 and the image display unit 12 are integrally configured.
  • the image display unit 12 is a part that displays a projected image based on image information from the control unit.
  • the specific configuration of the image display unit 12 is not limited, and for example, a liquid crystal display device, an organic EL display device, a light modulation element, or other conventionally known device can be used.
  • a liquid crystal display device is used as the image display unit 12.
  • the image display unit 12 is configured to include a far display area 12a and a near display area 12b that display a near image and a far image, respectively.
  • the far image displayed in the far display area 12a is irradiated as far image light L1
  • the near image displayed in the near display area 12b is irradiated as near image light L2.
  • the far display area 12a and the near display area 12b may each be configured with a separate display device, but it is preferable to use one display device divided into two areas.
  • the first plane mirror 13 is an optical member having a flat reflective surface.
  • the reflective surface of the first plane mirror 13 is disposed at a position where the distant image light L1 irradiated from the distant display area 12a is incident.
  • the reflective surface of the first plane mirror 13 is also disposed at a predetermined angle with respect to the distant display area 12a, and reflects the incident distant image light L1 in the direction of the second plane mirror 14.
  • the first plane mirror 13 corresponds to the first reflective surface in this disclosure.
  • the second plane mirror 14 has a flat reflective surface and is an optical component arranged opposite the first plane mirror 13.
  • the reflective surface of the second plane mirror 14 is arranged at a position where the distant image light L1 reflected by the first plane mirror 13 is incident.
  • the reflective surface of the second plane mirror 14 is also arranged at a predetermined angle with respect to the image display unit 12, and reflects the incident distant image light L1 in the direction of the primary mirror 20.
  • the second plane mirror 14 corresponds to the second reflective surface in this disclosure.
  • the mirror holding unit 50 is a member that is disposed on the light output side of the image display unit 12 and holds the first plane mirror 13 and the second plane mirror 14. By holding the first plane mirror 13 and the second plane mirror 14 with the mirror holding unit 50, the relative positional relationship and distance between them are maintained, and the reflection angle and optical distance of the distant image light L1 can be appropriately set.
  • FIG. 2 shows the first plane mirror 13 and the second plane mirror 14 as self-supporting flat plate-like members, the first and second reflection surfaces may be formed on the surface of the mirror holding unit 50 using deposition technology or plating technology. Details of the mirror holding unit 50 will be described later.
  • the far-distance image light L1 irradiated from the far-distance display area 12a is incident on the first plane mirror 13, reflected, and travels toward the second plane mirror 14.
  • the far-distance image light L1 that reaches the second plane mirror 14 is reflected again and reaches the primary mirror 20.
  • the first plane mirror 13 and the second plane mirror 14 are not disposed on the path of the near-distance image light L2 irradiated from the near-distance display area 12b. Therefore, the near-distance image light L2 irradiated from the near-distance display area 12b travels through the space between the first plane mirror 13 and the second plane mirror 14 to reach the primary mirror 20.
  • the near image light L2 is directly irradiated onto the primary mirror 20, whereas the far image light L1 is reflected by the first plane mirror 13 and the second plane mirror 14 and irradiated onto the primary mirror 20.
  • This causes a difference in optical distance between the near image light L2 and the far image light L1 until they reach the primary mirror 20, which is the distance W in the longitudinal direction of the image display unit 12.
  • the areas reached by the far image light L1 and the near image light L2 are different, and the paths of the far image light L1 and the near image light L2 reflected by the primary mirror 20 are also different.
  • This difference in optical distance and path causes the distance and imaging position of the virtual images P1, P2 from the windshield WS to differ.
  • the difference in optical distance between the far-distance image light L1 and the near-distance image light L2 is nW, which is the product of the distance W and the refractive index n. Because the refractive index of the material that makes up the prism is greater than 1, it is difficult to make the difference in optical distance between the far-distance image light L1 and the near-distance image light L2 smaller than nW.
  • the far-field image light L1 propagates between the first plane mirror 13 and the second plane mirror 14 through air with a refractive index of 1. Therefore, the difference in optical distance between the far-field image light L1 and the near-field image light L2 is W, which is the product of the longitudinal distance W of the image display unit 12 and the refractive index 1. Therefore, when the first plane mirror 13 and the second plane mirror 14 are used, the difference in optical distance between the far-field image light L1 and the near-field image light L2 can be reduced to about W.
  • the difference in optical distance can be made larger than W.
  • the image projection device 100 can appropriately branch multiple image lights, making it possible to reduce weight and improve design freedom.
  • FIG. 3A is a schematic perspective view showing an example of the structure of the mirror holding unit 50 in this embodiment.
  • FIG. 3B is a schematic cross-sectional view showing an example of the structure of the mirror holding unit 50 in this embodiment.
  • the mirror holding unit 50 has an attachment surface portion 51, a positioning hole 51a, side walls 52a and 52b, a first holding portion 53, a second holding portion 54, a notch portion 55, and a gap portion 56.
  • the image display unit 12 is provided with a mounting portion 12c and a positioning pin 12d.
  • the dashed arrows shown in FIG. 3A and FIG. 3B typically show the reference light beam of the far image light L1, and the dashed arrows typically show the reference light beam of the near image light L2.
  • the mirror holding portion 50 is a member in which the mounting surface portion 51, side walls 52a, 52b, first holding portion 53, and second holding portion 54 are integrally formed.
  • a first plane mirror 13 and a second plane mirror 14 are provided on the opposing surfaces of the first holding portion 53 and the second holding portion 54, respectively.
  • the first plane mirror 13 and the second plane mirror 14 are bonded to the first holding portion 53 and the second holding portion 54, but a first reflection surface and a second reflection surface may be formed on the surfaces of the first holding portion 53 and the second holding portion 54, respectively, using deposition technology or plating technology.
  • the material constituting the mirror holding portion 50 is not limited, and resin, metal, etc. can be used. From the viewpoint of moldability and weight reduction, it is preferable to use a resin material.
  • the mirror holding portion 50 including the first holding portion 53 and the second holding portion 54 can also be made of a material that blocks light.
  • the mounting surface portion 51 is a portion formed integrally with the first holding portion 53 and the second holding portion 54, and holds the first holding portion 53 and the second holding portion 54 so that the distance and angle between them and the image display portion 12 are constant.
  • the mounting surface portion 51 is a plate-shaped portion extending along the arrangement direction of the first plane mirror 13 and the second plane mirror 14 on the side of the first plane mirror 13 and the second plane mirror 14.
  • the mounting surface portion 51 is provided on the image display portion 12 side from the first plane mirror 13 and the second plane mirror 14, and has side walls 52a and 52b erected thereon.
  • the mounting surface portion 51 is provided with a plurality of positioning holes 51a.
  • the mounting surface portion 51 is a portion formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and corresponds to the connecting portion in this disclosure.
  • the positioning hole 51a is a hole that penetrates the mounting surface portion 51.
  • the positioning pin 12d provided on the mounting portion 12c is inserted into the positioning hole 51a.
  • the mirror holding portion 50 is positioned at a predetermined position on the image display portion 12, and the first plane mirror 13 and the second plane mirror 14 are also positioned relative to the image display portion 12.
  • the side walls 52a and 52b are wall-like parts that stand along the longitudinal direction of the mounting surface 51 in the width direction of the first retaining portion 53 and the second retaining portion 54, respectively.
  • the side walls 52a and 52b are provided on both sides of the first retaining portion 53 and the second retaining portion 54, and are formed integrally with the mounting surface 51, the first retaining portion 53, and the second retaining portion 54. In the example shown in Figures 3A and 3B, they are separated by a notch 55 formed between the side walls 52a and 52b.
  • the first holding portion 53 is a plate-shaped portion provided between the side walls 52a and holds the first plane mirror 13.
  • the first holding portion 53 is inclined at a predetermined angle with respect to the mounting surface portion 51 and is provided at a position facing the distant display area 12a of the image display unit 12.
  • the surface of the first holding portion 53 facing the distant display area 12a is a reflective surface, and the first plane mirror 13 is provided on the surface.
  • the first plane mirror 13 is formed separately from the mirror holding portion 50, and the first plane mirror 13 is attached to the reflective surface of the first holding portion 53.
  • the first reflective surface may be directly formed on the first holding portion 53 using deposition technology or plating technology.
  • the first reflective surface may also be formed by mirror-polishing the first holding portion 53.
  • the second holding portion 54 is a plate-shaped portion provided between the side walls 52b and holds the second plane mirror 14.
  • the second holding portion 54 is disposed at a predetermined angle with respect to the mounting surface portion 51, and is provided at a position facing the first holding portion 53 in the longitudinal direction of the mounting surface portion 51.
  • the first holding portion 53 and the second holding portion 54 may be parallel or non-parallel.
  • the surface of the second holding portion 54 facing the first holding portion 53 is a reflective surface, and the second plane mirror 14 is provided on the surface.
  • the second plane mirror 14 is formed separately from the mirror holding portion 50, and the second plane mirror 14 is bonded to the reflective surface of the second holding portion 54.
  • the second reflective surface may be directly formed on the second holding portion 54 using deposition technology or plating technology.
  • the second holding portion 54 may be mirror-polished to form the second reflective surface.
  • the notch 55 is a notch formed between the side walls 52a, 52b, and separates the side walls 52a, 52b between the first holding part 53 and the second holding part 54.
  • the notch 55 is provided, but the side walls 52a, 52b may be provided continuously along the mounting surface 51 without providing the notch 55.
  • the gap 56 is a space provided between the first holding part 53 and the second holding part 54.
  • the far image light L1 irradiated from the far display area 12a is reflected by the first plane mirror 13 and travels through the gap 56 along the longitudinal direction of the mounting surface part 51 to reach the second plane mirror 14.
  • the near image light L2 irradiated from the near display area 12b travels vertically through the gap 56 toward the primary mirror 20.
  • the gap 56 is not provided with a resin material or glass material having a high refractive index, but is filled with air having a low refractive index.
  • the gap 56 is open to the atmosphere and filled with air, but the mirror holding part 50 may be housed in an airtight container to create a vacuum in the gap 56.
  • FIG. 4 is a schematic cross-sectional view showing a method for forming the mirror holding part 50 in this embodiment.
  • FIG. 4 shows a cross section along the arrangement direction of the first holding part 53 and the second holding part 54, and other parts are omitted from the illustration.
  • molds 61 and 62 are prepared and a conventionally known injection molding technique can be used.
  • mold 61 is a cavity on the concave side
  • mold 62 is a core on the convex side.
  • the joints between molds 61 and 62 are parting lines PL1 to PL3, and by joining molds 61 and 62 and injecting resin into the hollow parts, each part of the mirror holding part 50 can be formed integrally.
  • the mounting surface portion 51 is formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and a gap is provided between the first holding portion 53 and the second holding portion 54. This keeps the distance and relative positional relationship between the first plane mirror 13 and the second plane mirror 14 constant, allowing multiple image light beams to be appropriately branched, making it possible to reduce weight and improve design freedom.
  • FIGS 5A and 5B are schematic perspective views showing a structural example of the mirror holding part 50 in this modified example.
  • This modified example differs from the first embodiment in that the side wall part 52 does not have a notch 55 and that the mounting surface part 51 is provided across the width direction on the bottom side of the first holding part 53.
  • the side wall portion 52 is continuously erected along the longitudinal direction of the mounting surface portion 51.
  • the first holding portion 53 and the second holding portion 54 are provided between the continuous side wall portions 52. Therefore, the gap portion 56 is surrounded on all four sides by the first holding portion 53, the second holding portion 54, and the side wall portion 52.
  • the mounting surface portion 51 and the side wall portion 52 are continuously provided in the longitudinal direction, so that the rigidity of the mirror holding portion 50 is increased, deformation is suppressed, and the distance and relative positional relationship between the first holding portion 53 and the second holding portion 54 can be kept constant.
  • the mounting surface portion 51 and the side wall portion 52 are formed integrally with the first holding portion 53 and the second holding portion 54 and are portions that connect the two, and correspond to the connecting portion in this disclosure.
  • the mounting surface portion 51 and the side wall portion 52 are formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and a gap portion 56 is provided between the first holding portion 53 and the second holding portion 54. This keeps the distance and relative positional relationship between the first plane mirror 13 and the second plane mirror 14 constant, allowing multiple image lights to be appropriately branched, making it possible to reduce weight and improve design freedom.
  • Figure 6A is a schematic top perspective view showing a structural example of the mirror holding unit 50 in this embodiment
  • Figure 6B is a schematic bottom perspective view showing a structural example of the mirror holding unit 50 in this embodiment.
  • the mirror holding unit 50 has an attachment surface portion 51, a positioning hole 51a, a side wall portion 52, a first holding unit 53, a second holding unit 54, a notch portion 55, a gap portion 56, and a top surface portion 57.
  • the mirror holding unit 50 including the first holding unit 53, the second holding unit 54, and the top surface portion 57 is made of a material that transmits light.
  • the top surface 57 is formed integrally with the side wall 52, the first holding portion 53, and the second holding portion 54, and is a plate-like portion provided on the light emission side of the second holding portion 54. Since the far image light L1 and the near image light L2 pass through the top surface 57, the mirror holding portion 50 is made of a material that transmits light.
  • the top surface 57, the side wall 52, and the mounting surface 51 are formed integrally with the first holding portion 53 and the second holding portion 54, and are portions that connect the two, and correspond to the connecting portion in this disclosure.
  • the gap portion 56 is surrounded on all four sides by the side wall 52, the first holding portion 53, and the second holding portion 54, and further the top surface 57 is provided on the light emission side.
  • the far-distance image light L1 irradiated from the far-distance display area 12a is reflected by the first plane mirror 13, travels through the gap 56 along the longitudinal direction of the mounting surface 51, is reflected by the second plane mirror 14, passes through the top surface 57, and travels toward the primary mirror 20.
  • the near-distance image light L2 irradiated from the near-distance display area 12b travels vertically through the gap 56, passes through the top surface 57, and travels toward the primary mirror 20.
  • FIG. 7A and 7B are schematic cross-sectional views showing a method for forming the mirror holding part 50 in this embodiment.
  • 7A and 7B show a cross section along the arrangement direction of the first holding part 53 and the second holding part 54, and other parts are not shown.
  • Mold 61 is a core on the convex side
  • mold 62 is a cavity on the concave side.
  • FIG. 7A shows a case where parting line PL3 is formed at the same height as top surface part 57
  • FIG. 7B shows a case where parting line PL3 is formed on the bottom side like parting line PL2.
  • each part of the mirror holding part 50 can be integrally formed by joining molds 61 and 62 and injecting resin into the hollow part.
  • the core mold 61 is provided with a shape corresponding to the gap 56, and the first holding portion 53 and the second holding portion 54 are inclined with respect to the parting lines PL2 and PL3.
  • the mirror holding portion 50 can be removed in the inclined direction of the first holding portion 53 and the second holding portion 54.
  • the top surface 57, mounting surface 51, and side wall 52 are formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and a gap 56 is provided between the first holding portion 53 and the second holding portion 54. This keeps the distance and relative positional relationship between the first plane mirror 13 and the second plane mirror 14 constant, allowing multiple image light beams to be appropriately branched, making it possible to reduce weight and improve design freedom.
  • Figure 8A is a schematic top perspective view showing a structural example of the mirror holding unit 50 in this embodiment
  • Figure 8B is a schematic bottom perspective view showing a structural example of the mirror holding unit 50 in this embodiment.
  • the mirror holding unit 50 has an attachment surface portion 51, a positioning hole 51a, a first holding unit 53, a second holding unit 54, a gap portion 56, a top surface portion 57, a top surface extension portion 58, and a positioning hole 58a.
  • the mirror holding unit 50 including the first holding unit 53, the second holding unit 54, and the top surface portion 57 is made of a material that transmits light.
  • the mounting surface portion 51 is formed by extending from the bottom of the first retaining portion 53 in the arrangement direction of the first retaining portion 53 and the second retaining portion 54.
  • the mounting surface portion 51 is not formed on the side of the first retaining portion 53 and the second retaining portion 54.
  • the side wall portion 52 is formed on the side of the first retaining portion 53 and the second retaining portion 54 along the arrangement direction of both.
  • the top surface extension portion 58 is a portion formed by extending the second retaining portion 54 side of the top surface portion 57 in the arrangement direction of the first retaining portion 53 and the second retaining portion 54.
  • the side wall portion 52 and the top surface portion 57 are portions formed integrally with the first retaining portion 53 and the second retaining portion 54 to connect them, and correspond to the connecting portion in this disclosure.
  • the top surface 57 and side wall 52 are also formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and a gap 56 is provided between the first holding portion 53 and the second holding portion 54. This keeps the distance and relative positional relationship between the first plane mirror 13 and the second plane mirror 14 constant, allowing multiple image lights to be appropriately branched, making it possible to reduce weight and improve design freedom.
  • Figure 9A is a schematic top perspective view showing a structural example of the mirror holding part 50 in this embodiment
  • Figure 9B is a schematic bottom perspective view showing a structural example of the mirror holding part 50 in this embodiment.
  • the mirror holding part 50 has an attachment surface part 51, a positioning hole 51a, a first holding part 53, a second holding part 54, a gap part 56, and a bottom surface part 59.
  • the mirror holding part 50 including the first holding part 53, the second holding part 54, and the bottom surface part 59 is made of a material that transmits light.
  • the bottom surface portion 59 is formed integrally with the side wall portion 52, the first holding portion 53, and the second holding portion 54, and is a plate-like portion provided on the light incident side of the first holding portion 53 and the second holding portion 54. Since the far image light L1 and the near image light L2 pass through the bottom surface portion 59, the mirror holding portion 50 is made of a material that transmits light.
  • the bottom surface portion 59, the side wall portion 52, and the mounting surface portion 51 are formed integrally with the first holding portion 53 and the second holding portion 54, and are portions that connect the two, and correspond to the connecting portion in this disclosure.
  • the gap portion 56 is surrounded on all four sides by the side wall portion 52, the first holding portion 53, and the second holding portion 54, and further has a bottom surface portion 59 provided on the light incident side.
  • the far-distance image light L1 irradiated from the far-distance display area 12a passes through the bottom surface 59 and is reflected by the first plane mirror 13, travels through the gap 56 along the longitudinal direction of the mounting surface 51, is reflected by the second plane mirror 14, and travels toward the primary mirror 20.
  • the near-distance image light L2 irradiated from the near-distance display area 12b passes through the bottom surface 59, traverses the gap 56, and travels toward the primary mirror 20.
  • the bottom surface portion 59, the mounting surface portion 51, and the side wall portion 52 are formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and a gap portion 56 is provided between the first holding portion 53 and the second holding portion 54.
  • FIG. 10A is a schematic top perspective view showing a structural example of the mirror holding part 50 in this embodiment
  • FIG. 10B is a schematic bottom perspective view showing a structural example of the mirror holding part 50 in this embodiment.
  • the mirror holding part 50 has an attachment surface part 51, a positioning hole 51a, a side wall part 52, a first holding part 53, a second holding part 54, and a gap part 56.
  • This embodiment is different from the first embodiment in that the attachment surface part 51 is formed only on the sides of the first holding part 53 and the second holding part 54, and the attachment surface part 51 is not formed across the width direction on the bottom side of the first holding part 53.
  • the mounting surface portion 51 and the side wall portion 52 are also formed integrally with the first holding portion 53 and the second holding portion 54 to connect the two, and a gap portion 56 is provided between the first holding portion 53 and the second holding portion 54. This keeps the distance and relative positional relationship between the first plane mirror 13 and the second plane mirror 14 constant, allowing multiple image light beams to be appropriately branched, making it possible to reduce weight and improve design freedom.
  • Figure 11A is a schematic top perspective view showing a structural example of the mirror holding part 50 in this embodiment
  • Figure 11B is a schematic bottom perspective view showing a structural example of the mirror holding part 50 in this embodiment.
  • the mirror holding part 50 has a top surface part 57, a top surface extension part 58, a positioning hole 58a, a first holding part 53, a second holding part 54, and a void part 56.
  • the top surface part 57 is a part formed integrally with the first holding part 53 and the second holding part 54 to connect them, and corresponds to the connecting part in this disclosure.
  • Figures 11A and 11B show an example in which the top surface extension portion 58 extends in the width direction of the first retaining portion 53 and the second retaining portion 54, but it may also extend in the arrangement direction of the first retaining portion 53 and the second retaining portion 54, as in Figures 8A and 8B.
  • the top surface 57 is also formed integrally with the first holding portion 53 and the second holding portion 54 to connect them together, and a gap portion 56 is provided between the first holding portion 53 and the second holding portion 54. This keeps the distance and relative positional relationship between the first plane mirror 13 and the second plane mirror 14 constant, allowing multiple image lights to be appropriately branched, making it possible to reduce weight and improve design freedom.
  • FIG. 12A is a schematic perspective view illustrating the structure of the primary mirror 20
  • FIG. 12B is a schematic horizontal cross-sectional view illustrating the structure of the primary mirror 20
  • FIG. 12C is a schematic vertical cross-sectional view illustrating the structure of the primary mirror 20.
  • the white arrows in FIGS. 12B and 12C diagrammatically indicate the direction of travel of the image light incident on the primary mirror 20.
  • the reflective surface of the primary mirror 20 is convex in the width direction (second direction) and concave in the height direction (first direction), forming a saddle shape. Therefore, the reflective surface of the primary mirror 20 provides positive optical power in the height direction and negative optical power in the width direction to the image light.
  • FIG. 13 is a schematic diagram showing an example of the configuration of the image projection unit 10.
  • the image projection unit 10 includes a light source unit 11, an image display unit 12, a first plane mirror 13, and a second plane mirror 14.
  • the image display unit 12 includes a far display area 12a and a near display area 12b.
  • the dashed arrows in FIG. 13 typically indicate the path (reference ray) of the center position of the far image light L1, and the dashed arrows typically indicate the path (reference ray) of the center position of the near image light L2.
  • the light source unit 11 is a part that irradiates the image display unit 12 with irradiation light.
  • the light source unit 11 is disposed on the rear side of the transmissive image display unit 12, and the irradiation light passes through the image display unit 12; however, a reflective image display unit 12 may be used to irradiate the irradiation light from the display surface side.
  • the specific configuration of the light source unit 11 is not limited, and a light-emitting diode or a laser light source may be used.
  • an organic EL display device is used as the image display unit 12, the light source unit 11 and the image display unit 12 are integrally configured.
  • the image display unit 12 is a part that displays a projected image based on image information from the control unit.
  • the specific configuration of the image display unit 12 is not limited, and for example, a liquid crystal display device, an organic EL display device, a light modulation element, or other conventionally known device can be used.
  • a liquid crystal display device is used as the image display unit 12.
  • the image display unit 12 is configured to include a far display area 12a and a near display area 12b that display a near image and a far image, respectively.
  • the far image displayed in the far display area 12a is irradiated as far image light L1
  • the near image displayed in the near display area 12b is irradiated as near image light L2.
  • the far display area 12a and the near display area 12b may each be configured with a separate display device, but it is preferable to use one display device divided into two areas.
  • the first plane mirror 13 is an optical member having a flat reflective surface.
  • the reflective surface of the first plane mirror 13 is disposed at a position where the distant image light L1 irradiated from the distant display area 12a is incident.
  • the reflective surface of the first plane mirror 13 is also disposed at a predetermined angle with respect to the distant display area 12a, and reflects the incident distant image light L1 in the direction of the second plane mirror 14.
  • the second plane mirror 14 is an optical member having a flat reflecting surface.
  • the reflecting surface of the second plane mirror 14 is disposed at a position where the distant image light L1 reflected by the first plane mirror 13 is incident.
  • the reflecting surface of the second plane mirror 14 is also disposed at a predetermined angle with respect to the image display unit 12, and reflects the incident distant image light L1 in the direction of the primary mirror 20.
  • the first plane mirror 13 and the second plane mirror 14 are not disposed on the path of the near image light L2 emitted from the near display area 12b. Therefore, the near image light L2 emitted from the near display area 12b travels through the space between the first plane mirror 13 and the second plane mirror 14 toward the primary mirror 20. While the near image light L2 is directly irradiated onto the primary mirror 20, the far image light L1 is reflected by the first plane mirror 13 and the second plane mirror 14 and irradiated onto the primary mirror 20. This creates an optical path difference between the near image light L2 and the far image light L1 until they reach the primary mirror 20, resulting in different imaging positions for the virtual images P1 and P2.
  • the first plane mirror 13 and the second plane mirror 14 are used to generate an optical path difference between the near image light L2 and the far image light L1, but the specific configuration for generating the optical path difference is not limited.
  • One example is a configuration in which a prism is used to branch the optical paths of the far image light L1 and the near image light L2 and the optical path length after branching is changed, or a configuration in which a reflecting prism is used to reflect the far image light L1 twice and transmit the near image light L2.
  • FIG. 14A is a side view explaining the positional relationship between the image irradiation unit 10, the primary mirror 20, and the secondary mirror 30, and the path of the image light
  • FIG. 14B is a top view explaining the positional relationship between the image irradiation unit 10, the primary mirror 20, and the secondary mirror 30, and the path of the image light.
  • the dashed lines shown in FIG. 14A and FIG. 14B are schematic diagrams showing the path of light irradiated from the end of the image irradiation unit 10.
  • the double-headed arrows shown in FIG. 14A indicate the distance d1 between the image irradiation unit 10 and the center of the reflective surface of the primary mirror 20, and the distance d2 between the center of the reflective surface of the primary mirror 20 and the center of the reflective surface of the secondary mirror 30.
  • the y-axis component of the image light is reflected by the primary mirror 20, condensed with positive optical power, and intermediately imaged at intermediate imaging position f, and then reaches the secondary mirror 30 while expanding.
  • the x-axis component of the image light is reflected by the primary mirror 20, expanded with negative optical power, and reaches the secondary mirror 30.
  • FIG. 15A is a schematic diagram illustrating the parallax caused by difference, showing left-right parallax
  • FIG. 15B is a schematic diagram illustrating the parallax caused by difference, showing up-down parallax.
  • the virtual image seen by the left eye when aberration occurs is drawn in solid lines as triangle PL
  • the virtual image seen by the right eye is drawn in dashed lines as triangle PR.
  • the virtual image in the ideal case where no aberration occurs and both eyes can see it in the same position is drawn in dashed lines as triangle PI.
  • the reflective surface of the primary mirror 20 has a saddle shape that is convex in the width direction and concave in the height direction, so that aberration in the width direction is reduced, improving the design freedom of the secondary mirror 30.
  • aberration correction in the height direction can be prioritized, improving the accuracy of aberration correction in the height direction.
  • the primary mirror 20 has a saddle shape and the accuracy of aberration correction in the height direction is improved, aberration can be corrected well even if the distance d1 from the image projection unit 10 to the primary mirror 20 is made small. Therefore, by making the distance d1 smaller than the distance d2 and satisfying the relationship d1 ⁇ d2, the image projection device 100 can be made smaller and thinner.
  • distance d1 from image projection unit 10 to primary mirror 20 be in the range of 30 mm to 100 mm, and more preferably in the range of 50 mm to 70 mm. If distance d1 is smaller than these ranges, the angle at which image light irradiated from image projection unit 10 expands over the entire reflective surface of primary mirror 20 becomes large, making aberration correction difficult. If distance d1 is larger than these ranges, it becomes difficult to make image projection device 100 smaller and thinner.
  • the far-distance image light is emitted from the far-distance display area 12a
  • the near-distance image light is emitted from the near-distance display area 12b.
  • the far-distance image light and the near-distance image light are incident on the reflecting surface of the primary mirror 20 at different positions in the height direction. Therefore, at least one of the positions at which the far-distance image light and the near-distance image light are reflected is deviated from the center position of the primary mirror 20 and the secondary mirror 30, and aberration in the height direction tends to be large.
  • the primary mirror 20 saddle-shaped and improving the accuracy of aberration correction in the height direction, the parallax occurring in the virtual images P1 and P2 can be reduced, and visibility can be improved.
  • the reflective surface of the primary mirror 20 is saddle-shaped, concave in the first direction and convex in the second direction, and the image light reflected by the primary mirror 20 is reflected by the secondary mirror 30, thereby improving the accuracy of aberration correction and improving the visibility of the formed virtual images P1 and P2.
  • the image irradiation unit 10 irradiates image light for far distances and image light for near distances to form two virtual images P1 and P2 at different imaging positions, but it is also possible to irradiate only one image light to form one virtual image.
  • the reflective surface of the primary mirror 20 is also saddle-shaped, concave in the first direction and convex in the second direction, and the image light reflected by the primary mirror 20 is reflected by the secondary mirror 30, which improves the accuracy of aberration correction and improves the visibility of the virtual image that is formed.
  • FIG. 16 is a schematic diagram showing an example configuration of the image irradiation unit 10.
  • the image irradiation unit 10 includes a light source unit 11, an image display unit 12, a first plane mirror 13, and a second plane mirror 14.
  • the image display unit 12 also includes a far display area 12a and a near display area 12b. Note that the configuration of the image irradiation unit 10 shown in FIG. 16 is the same as the configuration of the image irradiation unit 10 shown in FIG. 13, and therefore a description of the overlapping content will be omitted.
  • FIG. 17 is a schematic perspective view illustrating the paths of the far-distance image light L1 and near-distance image light L2 irradiated from the image irradiating unit 10.
  • the far-distance display area 12a and the near-distance display area 12b are arranged in a parallel direction in the image display unit 12. If the direction perpendicular to the parallel direction of the image display unit 12 is defined as the width direction, the far-distance image light L1 and near-distance image light L2 are irradiated at a predetermined angle in the width direction relative to the display surface of the image display unit 12. Therefore, the first plane mirror 13 and the second plane mirror 14 are arranged at positions shifted in the width direction relative to the image display unit 12.
  • the far-distance image light L1 irradiated from the far-distance display area 12a is incident on the first plane mirror 13, reflected, and travels toward the second plane mirror 14.
  • the far-distance image light L1 that reaches the second plane mirror 14 is reflected again and reaches the primary mirror 20.
  • the first plane mirror 13 and the second plane mirror 14 are not disposed on the path of the near-distance image light L2 irradiated from the near-distance display area 12b. Therefore, the near-distance image light L2 irradiated from the near-distance display area 12b travels through the space between the first plane mirror 13 and the second plane mirror 14 to reach the primary mirror 20.
  • the near image light L2 is directly irradiated onto the primary mirror 20, whereas the far image light L1 is reflected by the first plane mirror 13 and the second plane mirror 14 and irradiated onto the primary mirror 20.
  • This causes a difference in optical distance between the near image light L2 and the far image light L1 until they reach the primary mirror 20, which is the distance W in the parallel direction of the image display unit 12.
  • the areas reached by the far image light L1 and the near image light L2 are different, and the paths of the far image light L1 and the near image light L2 reflected by the primary mirror 20 are also different. This difference in optical distance and path causes the distance and imaging position of the virtual images P1, P2 from the windshield WS to differ.
  • the difference in optical distance between the far-distance image light L1 and the near-distance image light L2 is nW, which is the product of the distance W and the refractive index n. Because the refractive index of the material that makes up the prism is greater than 1, it is difficult to make the difference in optical distance between the far-distance image light L1 and the near-distance image light L2 smaller than nW.
  • the far-field image light L1 propagates between the first plane mirror 13 and the second plane mirror 14 through air with a refractive index of 1. Therefore, the difference in optical distance between the far-field image light L1 and the near-field image light L2 is W, which is the product of the distance W in the parallel direction of the image display unit 12 and the refractive index 1. Therefore, when the first plane mirror 13 and the second plane mirror 14 are used, the difference in optical distance between the far-field image light L1 and the near-field image light L2 can be reduced to approximately W. In addition, by arranging the second plane mirror 14 at a position away from the image display unit 12 in the parallel direction, the difference in optical distance can be made larger than W.
  • FIG. 18 is a schematic diagram explaining the angles of the first plane mirror 13 and the second plane mirror 14 in the image projection unit 10.
  • the projection angle of the image light from the image display unit 12 differs for each region, and the far-distance image light L1 projected from the far-distance display region 12a is projected at a projection angle ⁇ 1, and the near-distance image light L2 projected from the near-distance display region 12b is projected at a projection angle ⁇ 2. Therefore, the main projection direction of the near-distance image light L2 from the image display unit 12 is different from the main projection direction of the far-distance image light L1.
  • a virtual plane perpendicular to the reference ray of the far-distance image light heading toward the windshield WS is assumed, with the clockwise direction in the figure being the positive angular direction and the counterclockwise direction being the negative angular direction.
  • the first plane mirror 13 is disposed at a first angle ⁇ 1 with respect to the virtual plane
  • the second plane mirror 14 is disposed at a second angle ⁇ 2 with respect to the virtual plane.
  • the first plane mirror 13 and the second plane mirror 14 are used to create a difference in optical distance between the far-distance image light L1 and the near-distance image light L2, and there is no need to reduce the first angle ⁇ 1 and bring the first plane mirror 13 closer to the far-distance display area 12a. Therefore, the irradiation angle ⁇ 1 of the far-distance image light L1 irradiated from the far-distance display area 12a can be brought closer to 90 degrees.
  • the first angle ⁇ 1 of the first plane mirror 13 is in the range of -60 degrees or more and -45 degrees or less.
  • ⁇ which is the difference between the first angle ⁇ 1 and the second angle ⁇ 2 is preferably in the range of -10 degrees or more and +10 degrees or less, and more preferably in the range of -5 degrees or more and +5 degrees or less.
  • the distant image light L1 irradiated from the distant display area 12a is reflected by the first plane mirror 13 and the second plane mirror 14, thereby appropriately branching into multiple image lights, thereby making it possible to reduce weight and improve design freedom.
  • FIG. 19 is a schematic diagram illustrating an example of the configuration of the image projection unit 10 in this embodiment and the angles between the first plane mirror 13 and the second plane mirror 14. This embodiment differs from the ninth embodiment in that a polarizing reflection unit 15 is provided on the reflective surface of the second plane mirror 14.
  • the image projection unit 10 in the image projection device 100 of this embodiment includes an image display unit 12, a first plane mirror 13, a second plane mirror 14, and a polarizing reflection unit 15.
  • the image display unit 12 includes a far display area 12a and a near display area 12b.
  • the second plane mirror 14 may be made of a material that transmits light, or may be made of a material that blocks light.
  • the polarizing reflector 15 is an optical member that reflects polarized light in a predetermined direction and transmits polarized light in a direction intersecting the predetermined direction.
  • the polarizing reflector 15 is attached to the reflecting surface of the second plane mirror 14, but the second plane mirror 14 itself may be configured as a freestanding plate-shaped polarizing reflector 15.
  • the polarization direction reflected by the polarizing reflector 15 is set to the polarization direction of the image light irradiated from the image display unit 12.
  • the distant image light L1 irradiated from the distant display area 12a is reflected by the first plane mirror 13 and the polarizing reflector 15, and reaches the primary mirror 20.
  • the solid arrows in FIG. 19 show a schematic representation of external light LO reaching the image projection device 100 from outside.
  • the image projection device 100 is mounted on a vehicle or the like as shown in FIG. 1, and irradiates image light toward the windshield WS.
  • external light LO such as sunlight
  • incident from above the vehicle is partially reflected by the secondary mirror 30 and the primary mirror 20 and reaches the image irradiation unit 10.
  • Such external light LO can increase the surface temperature of the image display unit 12, causing deterioration.
  • external light LO that reaches the distant display area 12a is concentrated by the secondary mirror 30 and the primary mirror 20, and is therefore prone to causing an increase in temperature and deterioration.
  • the external light LO is unpolarized and contains polarized light reflected by the polarized reflector 15 and polarized light that is transmitted through it. Therefore, of the external light LO that reaches the polarized reflector 15, the polarized component in the above-mentioned specified direction is reflected toward the first plane mirror 13, while the polarized component perpendicular to the specified direction is transmitted through the polarized reflector 15. If the second plane mirror 14 is made of a material that blocks light, the external light LO that is transmitted through the polarized reflector 15 is absorbed by the second plane mirror 14. If the second plane mirror 14 is made of a material that transmits light, the external light LO that is transmitted through the polarized reflector 15 is absorbed by other components of the image projection device 100.
  • the energy of the external light LO that reaches the distant display area 12a is half of the energy of the external light LO that is incident on the polarizing reflector 15, and the temperature rise and deterioration of the distant display area 12a can be suppressed.
  • FIG. 20 is a schematic diagram for explaining the projection of virtual images P1 and P2 using the image projection device 100 according to this embodiment.
  • the dashed line in FIG. 20 indicates the optical path of the far-field image light (first image light) L1, which will be described later, and the dashed line indicates the optical path of the near-field image light (second image light) L2.
  • the far-field image light L1 and the near-field image light L2 projected from the image projection device 100 are reflected by the windshield (display unit) WS and irradiated to the driver's viewpoint.
  • the driver visually recognizes the virtual images P1 and P2 formed on the extension of the optical path along which the far-field image light L1 and the near-field image light L2 are incident.
  • the image projection device 100 projects the far-field image light L1 and the near-field image light L2 to form two images P1 and P2, but the number of virtual images is not limited.
  • the trajectory of light reaching the viewpoint from the direction in which the virtual images P1 and P2 are viewed is taken as the reference ray.
  • this reference ray can be considered to be approximately the same as the trajectory of light irradiated from the center of the effective area from which the light is emitted in the image irradiation unit 10 when it reaches the viewpoint.
  • Actual image light is irradiated from the image irradiation unit 10 over a specified area, and the light beam spreads from each position on the display surface, and is focused or expanded by the optical power of the reflective surfaces of the primary mirror 20 and the secondary mirror 30. Therefore, the reference ray shown in FIG. 20 does not indicate the path along which the irradiated light travels in the entire area of the image irradiation unit 10.
  • the windshield WS is a part that is provided in front of the driver's seat of the vehicle and transmits visible light.
  • the windshield WS reflects the far image light L1 and near image light L2 incident from the image projection device 100 toward the viewpoint and transmits light from outside the vehicle toward the viewpoint, and therefore corresponds to the display unit in this disclosure.
  • a combiner may be provided as a display unit separate from the windshield WS and reflect light from the image projection device 100 toward the viewpoint.
  • the display unit is not limited to being located at the front of the vehicle, and may be located to the side or rear as long as it projects an image toward the viewpoint of the passenger.
  • the virtual images P1 and P2 are images that are displayed as if they were formed in space when the far image light L1 and the near image light L2 reflected by the windshield WS reach the passenger's viewpoint (eyebox).
  • the positions at which the virtual images P1 and P2 are formed are determined by the composite focal length of the projection optical unit included in the image projection device 100 and the windshield WS.
  • the viewpoint is the eye (eyebox) of the driver or passenger of the vehicle, and the driver or passenger visually recognizes the formed virtual images P1 and P2 as the image light enters the eyebox and reaches the retina.
  • the distant image displayed in the distant display area of the image irradiation unit 10 is irradiated as distant image light L1
  • the near image displayed in the near display area is irradiated as near image light L2.
  • Distant images displayed in the distant display area include auxiliary information related to driving, such as images calling attention and emergency information.
  • Near images displayed in the near display area include speed and volume indicators, driving direction guides, etc.
  • the image projection device 100 includes an image projection unit 10, a primary mirror 20, a secondary mirror 30, a housing 60, and an optical member 70.
  • each part is controlled using a control unit (not shown) connected to each part so that information can be communicated.
  • the configuration of the control unit is not limited, but one example includes a CPU (Central Processing Unit) for performing information processing, a memory device, a recording medium, an information communication device, and the like.
  • the control unit controls the operation of each part according to a predetermined program, and sends information including an image (image information) to the image projection unit 10.
  • the image irradiation unit 10 is a part that irradiates the primary mirror 20 with light containing an image as image light based on image information from the control unit.
  • image information from the control unit In this embodiment, an example is shown in which two image lights displayed in two image display areas are irradiated onto the primary mirror 20 as far-distance image light L1 and near-distance image light L2.
  • the primary mirror 20 is an optical component that reflects the far-distance image light L1 and the near-distance image light L2 arriving from the image irradiation unit 10 toward the secondary mirror 30.
  • the primary mirror 20 is a flat reflecting mirror, but a concave or convex reflecting mirror may also be used.
  • the primary mirror 20 is made up of a curved surface, it is not limited to a surface with a constant curvature, and a paraboloid of revolution, an ellipsoid, a free-form surface mirror, etc. may be used.
  • the secondary mirror 30 is an optical component that reflects the far-distance image light L1 and near-distance image light L2 arriving from the primary mirror 20 in the direction of the windshield WS.
  • the secondary mirror 30 is a free-form mirror with an optically designed concave shape required for projecting the far-distance image light L1 and near-distance image light L2 as virtual images P1 and P2.
  • the reflective surfaces of the primary mirror 20 and the secondary mirror 30 are designed to expand the light diameter in the driver's viewpoint direction in order to project the far image light L1 and the near image light L2 as virtual images P1, P2 through the windshield WS.
  • the expansion of the light diameter in the viewpoint direction includes not only the case where the light diameter expands consistently after reflection, but also the case where the light diameter shrinks and expands after forming an image at an intermediate point.
  • the combination of the primary mirror 20 and the secondary mirror 30 has the function of projecting the far image light L1 and the near image light L2 through the windshield WS, and corresponds to the projection optical unit in this disclosure.
  • the housing 60 constitutes the outer shape of the image projection device 100 and is a container that houses each part.
  • the housing 60 is provided with a light exit port for emitting the far image light L1 and the near image light L2.
  • An angle adjustment unit for adjusting the angle of the secondary mirror 30 may also be provided within the housing 60 to adjust the irradiation angle of the far image light L1 and the near image light L2 projected onto the windshield WS and change the imaging height of the virtual images P1, P2.
  • the housing 60 may also be provided with an optical filter that cuts out ultraviolet light and infrared light contained in light (external light) arriving from the outside.
  • the optical member 70 is made of a material that transmits light, and is disposed on the light output side of the image irradiation unit 10. It is a part that repeatedly reflects the far image light L1 and transmits the near image light L2, thereby adjusting the optical path difference between the two.
  • the configuration of the optical member 70 will be described later.
  • the material that constitutes the optical member 70 it is preferable to use a resin material or glass material that has a high refractive index and high light transmittance.
  • the optical paths of the far-distance image light L1 and the near-distance image light L2 are depicted as a single straight arrow.
  • the actual far-distance image light L1 and near-distance image light L2 are displayed in a predetermined area in the image projection unit 10, and have a predetermined area in a direction perpendicular to the traveling direction, as indicated by the range shown by the dashed line in the figure.
  • the far-distance image light L1 and near-distance image light L2 are reflected by the primary mirror 20, and travel with their light diameters reduced, and may be intermediately imaged at an intermediate imaging position F (not shown) between the primary mirror 20 and the secondary mirror 30.
  • FIG. 22 is a schematic cross-sectional view showing an example of the configuration of the optical member 70 in this embodiment.
  • FIG. 22 shows only the image display section 12 on which the optical member 70 is arranged overlying, and the other parts are not shown.
  • FIG. 23 is a schematic perspective view showing an example of the configuration of the optical member 70 in this embodiment.
  • the image display unit 12 is a part that displays a projected image based on image information from the control unit.
  • the specific configuration of the image display unit 12 is not limited, and conventionally known devices such as a liquid crystal display device, an organic EL display device, or a light modulation element can be used.
  • the image display unit 12 is configured to include a far display area 12a and a near display area 12b that display a near image and a far image, respectively.
  • the far image light L1 irradiated from the far display area 12a is indicated by a solid arrow
  • the near image light L2 irradiated from the near display area 12b is indicated by a dashed arrow.
  • the light source unit (not shown in FIG. 22) irradiates the image display unit 12 with irradiation light.
  • the light source unit is disposed on the rear side of the transmissive image display unit 12, and the irradiation light passes through the image display unit 12; however, a reflective image display unit 12 may be used to irradiate the irradiation light from the display surface side.
  • the specific configuration of the light source unit is not limited, and a light-emitting diode or a laser light source may be used.
  • the light source unit and the image display unit 12 are configured as one unit.
  • the optical member 70 of this embodiment includes a first portion 71a, a second portion 71b, a light incident surface 71c, a refractive surface 71d, an inclined surface 71e, an inclined surface 71f, a connecting portion 71g, and an opening 71h.
  • a reflecting surface 72 is provided on the inclined surface 71f, and a reflecting surface 73 is provided on the inclined surface 71e.
  • a gap portion 74 is provided between the first portion 71a and the second portion 71b.
  • the first portion 71a is a part of the optical member 70 made of a light-transmitting material, and is the part where the distant image light L1 is incident.
  • the first portion 71a is formed integrally with the second portion 71b and the connecting portion 71g.
  • the first portion 71a is disposed so as to overlap the distant display area 12a of the image display unit 12, and the surface facing the distant display area 12a is the light incident surface 71c.
  • Part of the surface of the first portion 71a forms a refractive surface 71d and an inclined surface 71f.
  • the second portion 71b is a part of the optical member 70 made of a light-transmitting material, and is the part from which the distant image light L1 is emitted.
  • the second portion 71b is disposed opposite the first portion 71a, and part of its surface forms an inclined surface 71e.
  • the second portion 71b is formed in an approximately plate-like shape.
  • the light incident surface 71c is a flat surface that constitutes part of the surface of the first portion 71a, and is disposed opposite the far-display area 12a of the image display unit 12.
  • FIG. 22 shows an example in which the light incident surface 71c is disposed parallel to the far-display area 12a, but when the light incident surface 71c refracts the far-display image light L1, it may be inclined at a predetermined angle relative to the far-display area 12a.
  • the refractive surface 71d is a surface that constitutes part of the surface of the first portion 71a, and faces the gap portion 74.
  • the refractive surface 71d is formed perpendicular to the image display section 12, but it may be inclined at a predetermined angle relative to the image display section 12.
  • FIG. 22 shows an example in which the refractive surface 71d is provided near the boundary between the far display area 12a and the near display area 12b, the position is not limited as long as it is provided within a range that does not adversely affect the near image light L2.
  • the inclined surface 71e constitutes part of the surface of the second portion 71b, and is a surface on which the reflective surface 73 is provided, and is provided at a predetermined angle with respect to the image display unit 12.
  • the surface of the second portion 71b opposite the gap 74 is provided as the inclined surface 71e, but the surface facing the gap 74 may be provided as the inclined surface 71e and the reflective surface 73 may be provided.
  • the inclined surface 71f constitutes part of the surface of the first portion 71a, is a surface on which the reflective surface 72 is provided, and is inclined at a predetermined angle with respect to the image display unit 12. Since the inclined surface 71f is inclined with respect to the image display unit 12, the first portion 71a between the refracting surface 71d and the inclined surface 71f has a tapered shape with a different thickness in the horizontal direction in the figure.
  • the connecting portion 71g is made of a light-transmitting material and is formed integrally with the first portion 71a and the second portion 71b.
  • the connecting portion 71g is shown as a plate-shaped portion provided on the entire side of the gap portion 74, but the position and shape are not limited as long as the relative positional relationship between the first portion 71a and the second portion 71b can be maintained by forming the connecting portion 71g integrally with the first portion 71a and the second portion 71b.
  • the opening 71h is an opening formed in the optical member 70, and is provided opposite the near display region 12b.
  • the opening 71h is surrounded by the first portion 71a, the second portion 71b, and the connecting portion 71g, and an area without the material that constitutes the optical member 70 is formed from the opening 71h toward the inside of the optical member 70, forming a void portion 74.
  • Reflective surface 72 is a portion provided on inclined surface 71f that reflects light.
  • the configuration of reflective surface 72 is not limited, and a sheet-like member that reflects light may be attached to inclined surface 71f, or a metal material that reflects light may be vapor-deposited onto the surface of inclined surface 71f.
  • inclined surface 71f may be inclined at a greater angle than the critical angle, and light may be totally reflected at the interface between inclined surface 71f and air due to the difference between the refractive index of the material that constitutes first portion 71a and the refractive index of air. Reflective surface 72 corresponds to the first reflecting surface in this disclosure.
  • the reflective surface 73 is a portion provided on the inclined surface 71e that reflects light.
  • the configuration of the reflective surface 73 is not limited, and a sheet-like member that reflects light may be attached to the inclined surface 71e, or a metal material that reflects light may be vapor-deposited on the surface of the inclined surface 71e.
  • the inclined surface 71e may be inclined at a greater angle than the critical angle, and the light may be totally reflected at the interface between the inclined surface 71e and the air due to the difference in refractive index between the material that constitutes the first portion 71a and the refractive index of the air.
  • the reflective surface 73 corresponds to the second reflective surface in this disclosure.
  • the gap 74 is provided between the first portion 71a and the second portion 71b, and is an area that is free of the material that constitutes the optical member 70.
  • the gap 74 is also provided at a position that overlaps the near display area 12b.
  • Figs. 22 and 23 show an example in which the gap 74 is provided penetrating the optical member 70 from the image display unit 12 side (light entrance side) to the primary mirror 20 side (light exit side), the material that constitutes the optical member 70 may be present on either the light entrance side or the light exit side.
  • the image light L1 for distance irradiated from the far display area 12a enters the first portion 71a from the light incident surface 71c and reaches the reflecting surface 72 provided on the inclined surface 71f.
  • the image light L1 for distance is reflected by the reflecting surface 72 and turned back at the first portion 71a, and travels from the refraction surface 71d across the gap 74 to reach the second portion 71b.
  • the image light L1 for distance is refracted at the interface between the refraction surface 71d and the gap 74 depending on the incident angle of the image light L1 for distance to the refraction surface 71d.
  • the image light L1 for distance that reaches the second portion 71b is reflected again by the reflecting surface 73 provided on the inclined surface 71e and reaches the primary mirror 20.
  • the image light L2 for near irradiated from the near display area 12b travels through the gap 74 to reach the primary mirror 20.
  • the far image light L1 is reflected by the reflecting surfaces 72, 73 and irradiated onto the primary mirror 20.
  • This causes a difference in optical distance between the near image light L2 and the far image light L1 until they reach the primary mirror 20, which is the distance W in the longitudinal direction of the image display unit 12.
  • the far image light L1 and the near image light L2 reach different areas, and the paths of the far image light L1 and the near image light L2 reflected by the primary mirror 20 are also different. This difference in optical distance and path results in different distances and imaging positions of the virtual images P1, P2 from the windshield WS.
  • the first portion 71a, the second portion 71b, and the connecting portion 71g are integrally formed from a light-transmitting material, and the gap portion 74 is provided between the first portion 71a and the second portion 71b, which makes it possible to reduce weight and improve design freedom.
  • the gap portion 74 allows the thickness of the optical member 70 to be reduced, which suppresses deformation due to sink marks when molding the optical member 70 and improves molding accuracy.
  • the first portion 71a has a light incident surface 71c and a refraction surface 71d
  • the inclination angles of the light incident surface 71c and the refraction surface 71d with respect to the traveling direction of the distant image light L1 can be appropriately set to refract the distant image light L1. This improves the degree of freedom when designing the path of the distant image light L1 that travels from the first portion 71a to the second portion 71b.
  • the opening 71h and the gap 74 at a position overlapping the near display area 12b, even if the far image light L1 is refracted by the refracting surface 71d and enters the image display unit 12 side in the second portion 71b, it is possible to prevent a portion of the light from being reflected or scattered by the material that constitutes the optical member 70 and becoming stray light.
  • the connecting portion 71g on the side of the gap portion 74, the first portion 71a and the second portion 71b can be firmly integrated and their relative positional relationship can be maintained without optically affecting the far-distance image light L1 and the near-distance image light L2 traveling through the gap portion 74.
  • FIG. 24 is a schematic cross-sectional view showing a configuration example of an optical member 70 in this embodiment. This embodiment differs from the eleventh embodiment in that the image display unit 12 irradiates only one image light. As shown in FIG. 24, in this embodiment, a first portion 71a of the optical member 70 is arranged to overlap the image display unit 12, and the image display unit 12 is not provided in the gap portion 74.
  • image light irradiated from the image display unit 12 is incident on the first portion 71a from the light incident surface 71c and reaches the reflecting surface 72 provided on the inclined surface 71f.
  • the image light is reflected by the reflecting surface 72 and turned back at the first portion 71a, and reaches the second portion 71b through the refracting surface 71d, crossing the gap 74.
  • the image light is refracted at the interface between the refracting surface 71d and the gap 74, depending on the incident angle of the image light with respect to the refracting surface 71d.
  • the image light that reaches the second portion 71b is reflected again by the reflecting surface 73 provided on the inclined surface 71e, and reaches the primary mirror 20.
  • the first portion 71a, the second portion 71b, and the connecting portion 71g are integrally formed from a light-transmitting material, and a gap portion 74 is provided between the first portion 71a and the second portion 71b, making it possible to reduce weight and improve design freedom.
  • FIG. 25 is a schematic cross-sectional view showing a configuration example of an optical member 70 in this embodiment. This embodiment differs from the twelfth embodiment in that a connecting portion 71i is provided on the light emission side of a void portion 74.
  • the connecting portion 71i is made of a material that transmits light, and is formed integrally with the first portion 71a and the second portion 71b.
  • FIG. 25 shows only an example in which the connecting portion 71i is provided on the light-emitting side of the void portion 74, it may be used together with the connecting portion 71g provided on the side of the void portion 74 shown in the eleventh embodiment.
  • image light emitted from the image display unit 12 enters the first portion 71a from the light incident surface 71c and reaches the reflecting surface 72 provided on the inclined surface 71f.
  • the image light is reflected by the reflecting surface 72 and turned back at the first portion 71a, and reaches the second portion 71b by crossing the gap portion 74 from the refracting surface 71d.
  • the image light is refracted at the interface between the refracting surface 71d and the gap portion 74 depending on the incident angle of the image light with respect to the refracting surface 71d.
  • the image light that reaches the second portion 71b is reflected again by the reflecting surface 73 provided on the inclined surface 71e, and reaches the primary mirror 20 after passing through the connecting portion 71i.
  • the first portion 71a, the second portion 71b, and the connecting portion 71i are integrally formed from a material that transmits light, and a gap portion 74 is provided between the first portion 71a and the second portion 71b, which allows for weight reduction and improved design freedom. Furthermore, since the connecting portion 71i is provided on the light exit side of the gap portion 74, even if the image light is refracted at the refracting surface 71d and enters the image display unit 12 side of the second portion 71b, it is possible to prevent a portion of the light from being reflected or scattered by the material that constitutes the optical member 70 and becoming stray light.
  • FIG. 26 is a schematic cross-sectional view showing a configuration example of an optical member 70 in this embodiment. This embodiment differs from the twelfth embodiment in that a connecting portion 71j is provided on the light incident side of a gap portion 74.
  • the connecting portion 71j is made of a material that transmits light, and is formed integrally with the first portion 71a and the second portion 71b.
  • FIG. 26 shows only an example in which the connecting portion 71j is provided on the light incident side of the gap portion 74, it may be used together with the connecting portion 71g provided on the side of the gap portion 74 shown in the eleventh embodiment.
  • image light emitted from the image display unit 12 enters the first portion 71a from the light incident surface 71c and reaches the reflecting surface 72 provided on the inclined surface 71f.
  • the image light is reflected by the reflecting surface 72 and turned back at the first portion 71a, and reaches the second portion 71b by crossing the void portion 74 from the refracting surface 71d.
  • the image light is refracted at the interface between the refracting surface 71d and the void portion 74 depending on the incident angle of the image light with respect to the refracting surface 71d.
  • the image light that reaches the second portion 71b is reflected again by the reflecting surface 73 provided on the inclined surface 71e and reaches the primary mirror 20.
  • the first portion 71a, the second portion 71b, and the connecting portion 71j are integrally formed from a light-transmitting material, and a gap portion 74 is provided between the first portion 71a and the second portion 71b, making it possible to reduce weight and improve design freedom.
  • Fig. 27 is a schematic cross-sectional view showing a configuration example of an optical member 70 in this embodiment. This embodiment differs from the twelfth embodiment in that a refractive surface 71d is provided on the second portion 71b.
  • the refraction surface 71d is provided on the second portion 71b, and the second portion 71b between the refraction surface 71d and the inclined surface 71e has a tapered shape with a different thickness in the horizontal direction in the figure.
  • the first portion 71a is formed in an approximately plate shape.
  • a connecting portion 71g is provided on the side of the gap portion 74, but as in the thirteenth embodiment, a connecting portion 71i may be provided on the light exit side, and as in the fourteenth embodiment, a connecting portion 71j may be provided on the light entrance side.
  • the image light emitted from the image display unit 12 enters the first portion 71a and reaches the reflecting surface 72 provided on the inclined surface 71f.
  • the image light is reflected by the reflecting surface 72, turns back at the first portion 71a, crosses the gap 74, and enters the second portion 71b from the refracting surface 71d.
  • the image light is refracted at the interface between the refracting surface 71d and the gap 74.
  • the image light that reaches the second portion 71b is reflected again by the reflecting surface 73 provided on the inclined surface 71e, and is emitted from the light emitting surface 71k to reach the primary mirror 20.
  • the first portion 71a, the second portion 71b, and the connecting portion 71g are integrally formed from a light-transmitting material, and a gap portion 74 is provided between the first portion 71a and the second portion 71b, making it possible to reduce weight and improve design freedom.
  • Item 9 An image projection device that projects image light onto a display unit for displaying a virtual image, an image irradiating unit that irradiates the image light; a primary mirror that reflects the image light incident from the image irradiation unit; a secondary mirror that reflects the image light incident from the primary mirror; Equipped with An image projection device, wherein the reflective surface of the primary mirror is saddle-shaped, concave in a first direction and convex in a second direction.
  • Item 10 10. The image projection device according to item 9, wherein the image light reflected by the primary mirror is intermediately imaged in the first direction between the primary mirror and the secondary mirror.
  • Item 11 11.
  • Item 12 Item 12. The image projection device according to item 11, wherein a distance from the image irradiation unit to the primary mirror is in a range of 30 mm to 100 mm.
  • Item 13 the image irradiating unit irradiates near image light from a near display region and irradiates far image light from a far display region; a first plane mirror that reflects the far-field image light; a second plane mirror that reflects the far-distance image light reflected by the first plane mirror, 13.
  • the image projection device according to any one of items 9 to 12, wherein the near image light is incident on the primary mirror from the near display area, and the far image light is incident on the second plane mirror.
  • Item 14 An image projection device that projects image light onto a display unit for displaying a virtual image, an image display unit that irradiates near image light from a near display region and far image light from a far display region; a first plane mirror that reflects the far-field image light; a second plane mirror that reflects the far-distance image light reflected by the first plane mirror; a projection optical unit that irradiates the near image light incident from the near display area and the far image light incident from the second plane mirror onto the image display unit;
  • An image projection device comprising: Item 15: the first plane mirror is provided so as to be inclined at a first angle ⁇ 1 with respect to a virtual plane perpendicular to a reference ray of the far-distance image light directed toward the display unit, the second plane mirror is inclined at a second angle ⁇
  • the image projection device wherein a difference between the first angle ⁇ 1 and the second angle ⁇ 2 is in a range of ⁇ 5 degrees or more and +5 degrees or less.
  • Item 16 Item 16.
  • Item 17 the far-field image light includes polarized light in a predetermined direction, 17.
  • the second plane mirror includes a polarizing reflector that reflects polarized light in the predetermined direction and transmits polarized light in a direction intersecting the predetermined direction.
  • Item 18 18.
  • the image projection device according to any one of items 14 to 17, wherein a main irradiation direction of the near image light and a main irradiation direction of the far image light are different from each other.
  • the projection optical unit includes a primary mirror that reflects the near image light and the far image light.
  • Item 20 a first portion made of a light-transmitting material and having a first reflective surface; a second portion disposed opposite the first portion, the second portion being made of a material that transmits the light, and having a second reflecting surface; a connecting portion formed integrally with the first portion and the second portion to connect the first portion and the second portion; a gap portion provided between the first portion and the second portion, through which at least a portion of the light passes;
  • An optical member comprising: Item 21: 21. The optical member according to item 20, wherein at least a portion of the void portion is formed penetrating from the light incident side to the light exit side.
  • Item 23 23.
  • Item 26 26.
  • Item 27 An image projection device that projects image light onto a display unit for displaying a virtual image, An optical member according to any one of items 20 to 26, an image irradiating unit that irradiates the image light; a projection optical unit that irradiates the image light onto the display unit; Equipped with the image irradiating unit irradiates near image light from a near display region and irradiates far image light from a far display region; the distant image light is reflected by the first reflecting surface and the second reflecting surface to reach the projection optical unit, The near image light passes through the gap and reaches the projection optical unit.

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Abstract

Cet élément optique comprend : une première surface de réflexion (13) ; une seconde surface de réflexion (14) disposée de manière à faire face à la première surface de réflexion (13) ; une partie d'écartement (56) disposée entre la première surface de réflexion (13) et la seconde surface de réflexion (14); une première partie de maintien (53) pour maintenir la première surface de réflexion (13); une seconde partie de maintien (54) pour maintenir la seconde surface de réflexion (14); et une partie de liaison (51) formée d'un seul tenant avec la première partie de maintien (53) et la seconde partie de maintien (54) et reliant les deux.
PCT/JP2024/033277 2023-10-02 2024-09-18 Élément optique et dispositif de projection d'image Pending WO2025074861A1 (fr)

Applications Claiming Priority (8)

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JP2023-171710 2023-10-02
JP2023171710A JP2025062543A (ja) 2023-10-02 2023-10-02 光学部材および画像投影装置
JP2023-188973 2023-11-03
JP2023188973A JP2025077059A (ja) 2023-11-03 2023-11-03 画像投影装置
JP2023188972A JP2025077058A (ja) 2023-11-03 2023-11-03 画像投影装置
JP2023-188972 2023-11-03
JP2023199454A JP2025085522A (ja) 2023-11-24 2023-11-24 光学部材および画像投影装置
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JP2021173812A (ja) * 2020-04-22 2021-11-01 セイコーエプソン株式会社 投写光学装置およびプロジェクター
CN113296266A (zh) * 2021-06-07 2021-08-24 合肥疆程技术有限公司 一种显示系统、车载抬头显示器和车辆
JP2023076353A (ja) * 2021-11-22 2023-06-01 株式会社小糸製作所 画像照射装置

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