JP2015069111A - Image display device, screen and image display method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image display device, a screen and an image display method that improve visibility of images to be displayed in a display part, and suppress fall-off of visibility in a forward viewing field to a minimum level.SOLUTION: An image display device comprises: a screen comprising a first transparent film having a first transparent electrode, a second transparent film having a second transparent electrode, and a light adjustment layer arranged between the first transparent film and the second transparent film, in which transmittance is changed in accordance with a drive voltage to be applied between the first transparent electrode and the second transparent electrode; a projection part that causes an image to be displayed with the image projected on the screen; and a light adjustment control part that controls the drive voltage to be applied between the first transparent electrode and the second transparent electrode corresponding to a light adjustment area serving as a part of the light adjustment layer in a peripheral part of a display element contained in at least the image displayed on the screen, and executes light adjustment control that causes transmittance of the light adjustment area to be made lower than that of a part outside the light adjustment area.

Description

  The present invention relates to an image display device, a screen, and an image display method.

  2. Description of the Related Art In recent years, an image display device (head-up display (HUD)) that is mounted on a vehicle or the like and reflected on a display unit (screen) such as a combiner or a windshield to display the image projected from a projection device or the like so that the driver can visually recognize it. : Head-Up Display) device) has been proposed. Among such image display apparatuses, an apparatus has been proposed that improves the visibility of an image displayed on the display unit by controlling the transmittance with respect to external light in a display unit that displays (projects) the image.

  Of such an image display device that controls the transmittance of the display unit, a portion that becomes the display unit of the windshield is divided into a plurality of regions, and each region transmits external light and does not transmit light There is an apparatus that can switch between (see Patent Document 1). When displaying an image projected from the projection apparatus, the image display apparatus switches the display area to an opaque state.

  Further, among image display devices that control the transmittance of the display unit, a device that adjusts the contrast of the image projected on the screen by controlling the transmittance of the screen serving as the display unit, thereby improving the visibility of the image. (See Patent Document 2).

JP-A-8-175225 JP 2002-104017 A

  However, when displaying an image, the image display device described in Patent Document 1 sets the portion of the display unit on which the image is projected to an opaque state that blocks outside light. The portion of the display unit that is in a transmissive state blocks the front field of view, which has the problem of hindering driving.

  Moreover, since the image display apparatus described in patent document 2 is reducing the transmittance | permeability of the whole screen in order to improve the visibility of the image displayed on the screen used as a display part, it is equivalent to that during operation. As a result, the front field of view is darkened, and as in the case described above, there is a problem that hinders driving.

  The present invention has been made in view of the above, and provides an image display device, a screen, and an image display method that improve the visibility of an image displayed on a display unit and suppress a decrease in the visibility of a front field of view. The purpose is to provide.

  In order to solve the above-described problems and achieve the object, the present invention includes a screen including a light control layer whose transmittance can be controlled for each region, a projection unit that projects and displays an image on the screen, and at least The transmittance of the light control region, which is the region of the light control layer corresponding to the peripheral portion of the display element included in the image displayed on the screen, is lower than the transmittance of the outer portion of the light control region. A dimming control unit that performs light control.

  ADVANTAGE OF THE INVENTION According to this invention, the fall of the visibility of a forward visual field can be suppressed to the minimum, improving the visibility of the image displayed on a display part.

FIG. 1 is a diagram illustrating an example of a state in which the image display device according to the first embodiment is mounted on a vehicle. FIG. 2 is a diagram illustrating a configuration example of functional blocks of the image display apparatus according to the first embodiment. FIG. 3 is a diagram illustrating a structure example of the light control film and the combiner according to the first embodiment. FIG. 4 is a diagram for explaining a change in transmittance of the liquid crystal layer according to the first embodiment. FIG. 5 is a diagram illustrating a display example of an image at night of the entire combiner according to the first embodiment. FIG. 6 is a diagram illustrating a display example of display elements on the combiner according to the first embodiment. FIG. 7 is a diagram illustrating a display example of an image in the daytime of the entire combiner according to the first embodiment. FIG. 8 is a diagram illustrating an example of a state in which the image display device according to the modified example of the first embodiment is mounted on a vehicle. FIG. 9 is a diagram illustrating a structure example of a light control film according to the second embodiment. FIG. 10 is a diagram for explaining a change in reflectance of the light control layer according to the second embodiment. FIG. 11: is a structural example of the light control area | region in the light control film of the combiner which concerns on 3rd Embodiment. FIG. 12 is a diagram illustrating a display example of an image of the entire combiner according to the third embodiment.

  Hereinafter, embodiments of an image display device, a screen, and an image display method according to the present invention will be described in detail with reference to the drawings. Further, the present invention is not limited by the following embodiments, and components in the following embodiments can be easily conceived by those skilled in the art, are substantially the same, and have a so-called equivalent range. Is included. Furthermore, various omissions, substitutions, and changes of the constituent elements can be made without departing from the scope of the following embodiments.

(First embodiment)
<Configuration of image display device>
FIG. 1 is a diagram illustrating an example of a state in which the image display device according to the first embodiment is mounted on a vehicle. FIG. 2 is a diagram illustrating a configuration example of functional blocks of the image display apparatus according to the first embodiment. The configuration of the image display apparatus 300 according to the present embodiment will be described with reference to FIGS.

  As shown in FIGS. 1 and 2, an image display device 300 that is a head-up display device includes a projection device 10 and a combiner 30.

  As shown in FIG. 1, the projection device 10 is a device that projects an image onto the combiner 30. The projection device 10 is installed above the driver 5 of the passenger compartment 3, which is the room space of the vehicle body 2 of the vehicle 1.

  The combiner 30 is a member that serves as a screen that reflects the image projected from the projection device 10 and allows the driver 5 to visually recognize the reflected image. The combiner 30 is installed above the windshield 2a of the vehicle body 2, and is installed at a position that covers a part of the field of view of the driver 5 over the windshield 2a.

  The projection light 201 including the image projected from the projection device 10 is reflected by the combiner 30, and the reflected light 202 enters the eyes of the driver 5. As a result, the driver 5 visually recognizes that the image (virtual image 221) is displayed ahead of the predetermined distance (for example, 2 to 4 [m], etc.) in the visual field 211 through the combiner 30.

  Next, functional blocks of the image display device 300 will be described with reference to FIG. As shown in FIG. 2, the projection device 10 of the image display device 300 includes a radio wave reception unit 11, a positioning unit 12, an operation input unit 13, a data input unit 14, a wireless communication unit 15, and a storage unit 16. , A control unit 17, an image generation unit 18, a projection unit 19, a dimming control unit 20, a first electrode drive unit 21a, and a second electrode drive unit 21b.

  The radio wave receiving unit 11 has an antenna shape and receives radio waves from a plurality of GPS (Global Positioning System) satellites. The positioning unit 12 specifies the current location of the image display device 300 based on the plurality of radio waves received by the radio wave receiving unit 11, and passes the position information to the control unit 17. For example, when the radio wave reception unit 11 receives radio waves from three GPS satellites, the positioning unit 12 can specify the latitude and longitude where the image display device 300 exists.

  The operation input unit 13 is input by the user such as the driver 5 such as system setting, destination designation and registration, and passes the operation information to the control unit 17. The operation input unit 13 is realized by a switch, a touch panel, a voice recognition input device, or the like.

  The data input unit 14 receives data related to the vehicle and passes the data to the control unit 17. The data input unit 14 is connected to an illuminance sensor 22 (illuminance detection unit) that detects illuminance (brightness) outside the vehicle 1, and passes the illuminance information received from the illuminance sensor 22 to the control unit 17. Here, the illuminance information is used to control the transmittance of the light control film 32 by controlling the projection light amount of the projection unit 19 and controlling the first electrode drive unit 21a and the second electrode drive unit 21b by the light control unit 20. It is done. Further, the data input unit 14 receives vehicle data such as a vehicle speed and a steering angle detected from a vehicle speed sensor (not shown), and passes them to the control unit 17. The illuminance sensor 22 detects the illuminance outside the vehicle 1, but is not limited to this, as long as the illuminance around the combiner 30 can be detected.

  Regarding the visibility of the display image in the HUD device, the illuminance (brightness) of light from the outside of the vehicle (hereinafter referred to as ambient light) that passes through the combiner and the light of the image projected on the combiner are reflected by the combiner. Various experiments and studies have been conducted on the relationship between the illuminance (brightness) of the emitted light (hereinafter referred to as image light). For example, referring to the document “Human Factors Aspects of Using Head Up Displays in Automobiles: A Review of the Literate”, in the case of a conventional HUD device, the visibility changes depending on various conditions such as the brightness of the outside of the vehicle. It seems that the ratio of ambient light to image light is generally suitable in the range of 1: 1.2 to 1: 2. Here, it is assumed that 1: 1.5 is suitable as an example, but the present invention is not limited to this.

  The wireless communication unit 15 receives in real time traffic information such as road traffic congestion or traffic regulation edited by the VICS (registered trademark) (Vehicle Information and Communication System) center, and passes the traffic information to the control unit 17. .

  The storage unit 16 stores map information and the like for executing processing such as map mapping based on the position information received from the positioning unit 12 in the control unit 17. The storage unit 16 is realized by a storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

  The control unit 17 controls the entire image display device 300. For example, when there is an error in the position information received from the positioning unit 12, the control unit 17 determines the map information from the map information stored in the storage unit 16 and the moving direction of the image display device 300 based on the position information. Map mapping is performed to find the corresponding road, identify the correct current location, and correct the position information. In addition, the control unit 17 passes information necessary for the image generation unit 18 to generate image data indicating the traveling direction and distance of the next turn, to the image generation unit 18. The information necessary for generating image data includes, for example, position information received from the positioning unit 12, map information read from the storage unit 16, vehicle speed information received from the data input unit 14, and the like.

  The image generation unit 18 receives position information, map information, vehicle speed information, and the like from the control unit 17, generates image data for causing the projection unit 19 to display an image for assisting the driver 5 in driving, and generates the image data. The obtained image data is transferred to the projection unit 19. The image for assisting the driving of the driver 5 is, for example, as shown in FIGS. 5 and 7 to be described later, the direction of travel of the next turn, the distance to the turn, the lane indication at the turn, and the purpose It is an image including the estimated arrival time to the point.

  The projection unit 19 projects and projects an image toward the combiner 30 based on the image data received from the image generation unit 18.

  The dimming control unit 20 transmits a driving signal for controlling the transmittance of the dimming film 32 of the combiner 30 described later to the first electrode driving unit 21a and the second electrode driving unit 21b. Thereby, the light control unit 20 controls the transmittance in each part of the light control film 32 so that the visibility of the image projected on the combiner 30 is increased. The control of the transmittance of the light control film 32 for increasing the visibility of the image projected on the combiner 30 will be described later.

  The first electrode driving unit 21a and the second electrode driving unit 21b are driven between the first transparent electrode 42b and the second transparent electrode 43b of the light control film 32 described later according to the drive signal received from the light control unit 20. A voltage is applied to change the transmittance of the light control film 32.

  The combiner 30 is a member that reflects the image projected from the projection unit 19 so as to be visible to the driver 5. As will be described later, the light control film 32 is attached to the combiner 30. As described above, the transmittance of the light control film 32 varies depending on the drive voltage applied by the first electrode driver 21a and the second electrode driver 21b.

<Combiner and light control film structure>
FIG. 3 is a diagram illustrating a structure example of the light control film and the combiner according to the first embodiment. The structure of the combiner 30 and the light control film 32 is demonstrated referring FIG.

  As shown in FIG. 3A, the combiner 30 has a structure in which a surface of one side of a transparent plate 31 such as glass or transparent resin that transmits light is covered with a light control film 32.

  As shown in FIG.3 (b), the light control film 32 is the 1st film 41a, the 1st transparent conductive film 42 (1st transparent film), the liquid crystal layer 44 (light control layer), the 2nd transparent conductive film 43 ( The second transparent film) and the second film 41b are stacked in this order.

  The first film 41a and the second film 41b are made of a material such as PET (polyethylene terephthalate), for example, and transmit incident light, and the first transparent conductive film 42, the liquid crystal layer 44, and the second transparent conductive film. It has a function of protecting the film 43.

  As shown in FIG. 3C, the first transparent conductive film 42 and the second transparent conductive film 43 have a first transparent electrode 42b and a second transparent electrode 43b having conductivity, respectively. An electric field is formed in the liquid crystal layer 44 by applying a driving voltage to the first transparent electrode 42b and the second transparent electrode 43b.

  The liquid crystal layer 44 is formed by dispersing a large number of liquid crystals 44a encapsulated in a polymer with a size of about several microns. When a driving voltage is applied between the first transparent electrode 42b and the second transparent electrode 43b, the liquid crystal 44a is aligned so that the major axis direction is parallel to the electric field direction. When the major axis direction of the liquid crystal 44a is aligned along the electric field direction, light incident on the light control film 32, that is, light incident on the liquid crystal layer 44 is transmitted. Further, the degree of orientation of the liquid crystal 44a in the liquid crystal layer 44 changes depending on the magnitude of the driving voltage applied between the first glass substrate 42a and the second transparent electrode 43b, and the light transmittance to the liquid crystal layer 44 is changed. Also changes. Therefore, the dimming control unit 20 controls the light transmittance of the dimming film 32 by controlling the magnitude of the driving voltage via the first electrode driving unit 21a and the second electrode driving unit 21b. Can do. Although depending on the structure of the liquid crystal layer 44, the type of the liquid crystal 44a, and the like, here, as the drive voltage applied between the first glass substrate 42a and the second transparent electrode 43b increases, the transmittance of the liquid crystal layer 44, That is, the description will be made assuming that the transmittance of the light control film 32 is increased. In addition, there is nothing which is not limited to the thing which the transmittance | permeability of the light control film 32 becomes large, so that the drive voltage stamped between the 1st glass substrate 42a and the 2nd transparent electrode 43b is large, and so that drive voltage is large. It goes without saying that the transmittance of the light control film 32 may be small.

  FIG. 3C is a diagram schematically showing a laminated structure of the first transparent conductive film 42, the second transparent conductive film 43, and the liquid crystal layer 44. As shown in FIG. 3C, the liquid crystal layer 44 is disposed between the first transparent conductive film 42 and the second transparent conductive film 43.

  The first transparent conductive film 42 is configured by arranging a plurality of first transparent electrodes 42b in a stripe shape on the first glass substrate 42a. The plurality of first transparent electrodes 42b are respectively connected to the first electrode driving unit 21a, and a driving voltage is independently applied by the first electrode driving unit 21a.

  The second transparent conductive film 43 is configured by arranging a plurality of second transparent electrodes 43b in parallel in a stripe shape in a direction intersecting with the first transparent electrode 42b on the second glass substrate 43a. The plurality of second transparent electrodes 43b are respectively connected to the second electrode drive unit 21b, and a drive voltage is independently applied by the second electrode drive unit 21b.

  With the above configuration, the points (intersections) where the plurality of first transparent electrodes 42b and the plurality of second transparent electrodes 43b intersect are arranged in a matrix. This matrix intersection is determined by a specific electrode among the plurality of first transparent electrodes 42b and the second transparent electrodes 43b. Therefore, by applying a driving voltage to specific electrodes of the first transparent electrode 42b and the second transparent electrode 43b, an electric field can be formed in the portion of the liquid crystal layer 44 corresponding to the intersection of the specific electrodes. Therefore, the portion of the liquid crystal layer 44 corresponding to each of the intersections in the matrix can control the light transmittance independently.

  As described above, the matrix formed by the plurality of first transparent electrodes 42b and the second transparent electrodes 43b is in the form of a so-called passive matrix, but is not limited thereto, and is not limited to TFT (Thin Film). It may be formed by an active matrix including a switching element such as a transistor (thin film transistor).

<Light transmission operation in liquid crystal layer>
FIG. 4 is a diagram for explaining a change in transmittance of the liquid crystal layer according to the first embodiment. With reference to FIG. 4, the light transmission operation with and without an electric field formed in the liquid crystal layer 44 will be described.

  FIG. 4A is a diagram illustrating the behavior of the incident light 61 when a predetermined driving voltage is applied between the first transparent conductive film 42 and the second transparent conductive film 43. Since a driving voltage having a predetermined magnitude is applied between the first transparent conductive film 42 and the second transparent conductive film 43, an electric field proportional to the driving voltage is formed in the liquid crystal layer 44. The liquid crystal layer 44 has a high light transmittance. In this state, incident light 61 incident on the liquid crystal layer 44 is emitted from a surface opposite to the surface of the liquid crystal layer 44 on which the incident light 61 is incident, as most of the transmitted light 62 transmitted through the liquid crystal layer 44. Part of the incident light 61 is reflected by the liquid crystal layer 44 as reflected light 63 on the same side as the surface of the liquid crystal layer 44 on which the incident light 61 is incident.

  FIG. 4B shows the behavior of the incident light 61 when a driving voltage smaller than that in FIG. 4A is applied between the first transparent conductive film 42 and the second transparent conductive film 43. FIG. Since a driving voltage smaller than that in the case of FIG. 4A is applied between the first transparent conductive film 42 and the second transparent conductive film 43, an electric field proportional to the driving voltage is applied to the liquid crystal layer 44. The liquid crystal layer 44 has a light transmittance lower than that in the case of FIG. In this state, among the incident light 61 incident on the liquid crystal layer 44, transmitted light 64 having a light amount smaller than the transmitted light 62 is emitted from a surface opposite to the surface of the liquid crystal layer 44 on which the incident light 61 is incident. Further, part of the incident light 61 is reflected by the liquid crystal layer 44 as reflected light 65 having a larger light quantity than the reflected light 63 on the same side as the surface of the liquid crystal layer 44 on which the incident light 61 is incident.

  In FIG. 4, the behavior of the transmitted light and the reflected light of the incident light 61 is schematically described according to the magnitude of the electric field formed in the liquid crystal layer 44. The amount of transmitted light and reflected light in the incident light can be controlled.

<Image to be projected onto combiner>
FIG. 5 is a diagram illustrating a display example of an image at night of the entire combiner according to the first embodiment. A display example of an image projected (displayed) on the combiner 30 at night will be described with reference to FIG.

  FIG. 5 shows a display example of an image projected on the combiner 30 at night. The combiner 30 displays, for example, a direction display element 51, a spot display element 52, a scheduled time display element 53, and a lane display element 54 according to the image projected from the projection device 10.

  The amount of external light (ambient light) incident on the combiner 30 from the outside on the windshield 2a side is small at night compared to daytime. Therefore, as shown in FIG. 5, at night, various symbols such as the direction display element 51 and the lane display element 54 included in the image projected on the combiner 30, and various points such as the point display element 52 and the scheduled time display element 53 are displayed. Even if the character is projected onto the combiner 30 in a state that is 1.5 times brighter than the ambient light, the amount of image light can be suppressed. Therefore, the image light from the projection device 10 does not give glare to the driver 5, and sufficient visibility can be ensured.

  The direction display element 51 is a display element that indicates the traveling direction of the next corner. The point display element 52 is a display element indicating the distance to the next corner. The scheduled time display element 53 is a display element indicating the arrival time to the destination point. The lane display element 54 is a display element that indicates a lane at the next corner.

  FIG. 6 is a diagram illustrating a display example of display elements on the combiner according to the first embodiment. With reference to FIG. 6, in the present embodiment, the light control operation of the light control film 32 of the combiner 30 and the display operation of the display element when the illuminance of outside light is high will be described.

  FIG. 6A shows a state where the display element 71 is displayed as it is on the combiner 30. When the illuminance outside the vehicle 1 is low compared to the daytime (the amount of external light is small), such as at night, the driver 5 even if the image light is set to 1.5 times the ambient light as described above. On the other hand, the visibility can be sufficiently secured without giving glare. However, when the illuminance outside the vehicle 1 is higher than at night (the amount of external light is large) as in the daytime, the driver must display the display element 71 with a light amount larger than the amount of ambient light. 5 is difficult to visually recognize the display element 71. Therefore, even in this case, if the display element 71 is displayed 1.5 times brighter than the ambient light, even if the ambient light has a brightness that does not give glare to the driver 5, the display element 71 This may give glare to the driver 5 and hinder the driving of the driver 5.

  Therefore, in the daytime, that is, when the illuminance outside the vehicle 1 detected by the illuminance sensor 22 is higher than a predetermined value, the dimming control unit 20, as shown in FIG. , The transmittance of the light control region 72 having a larger area than the region of the display element 71 is reduced below the transmittance of the portion around the light control region 72 (light control). Specifically, the dimming control unit 20 applies the first electrode driving unit 21a to the first transparent electrode 42b and the second transparent electrode 43b corresponding to the matrix intersections included in the dimming region 72 of the dimming film 32. And the drive voltage applied via the 2nd electrode drive part 21b is adjusted, and the transmittance | permeability of the light control area | region 72 is reduced. Since the area of the dimming area 72 is larger than the area of the area of the display element 71, the display element 71 is displayed as if it is bordered by the dimming area 72 having reduced transmittance as shown in FIG. Is done.

  As described above, the display element 71 is projected on the light control region 72 after the transmittance of the light control region 72 having a larger area than the area of the display element 71 is lowered. It is displayed as outlined by the dimming area 72. As a result, the display element 71 is displayed on the dimming area 72, which has a reduced transmittance and appears dark to the driver 5, and the display element 71 is displayed as bordered by the dimming area 72. And the visibility with respect to the display element 71 of the driver | operator 5 improves. However, when the transmittance is reduced in the light control region 72, the external light is not completely blocked, but the external light is transmitted only to some extent, so that the field of view through the light control region 72 is secured. It is preferable. As a result, external light is completely blocked in the light control area 72, and it is possible to suppress troubles to the driving of the driver 5 due to the visual field being blocked by the light control area 72.

  Further, since the display element 71 is displayed in the light control area 72 that appears to be dark for the driver 5 due to a decrease in the transmittance, there is no need to display the display element 71 with a light amount 1.5 times that of the ambient light. Although it is also affected by the color of the display element 71, sufficient visibility can be obtained even with a light amount of about 1 to 1.2 times. Accordingly, the light amounts of the ambient light and the image light do not greatly differ, and the display element 71 does not give the driver 5 glare. In addition, since the display element 71 can be projected with lower brightness than in the prior art, the power consumption of the image display device 300 can be suppressed.

  Next, a case is assumed where the outside of the vehicle 1 is brighter (the illuminance is higher) than in the case of FIG. In this case, even if the area of the light control region 72 for reducing the transmittance is made somewhat larger than the area of the region of the display element 71, the visibility of the driver 5 with respect to the display element 71 may still be poor. In this case, as shown in FIG. 6C, the transmittance of the light control region 72a having an area larger than the area of the light control region 72 shown in FIG. ), The width of the light control region that borders the display element 71 can be increased. Thereby, the fall of the visibility with respect to the display element 71 of the driver | operator 5 can be suppressed.

  As described above, as the illuminance outside the vehicle 1 detected by the illuminance sensor 22 increases, the border width of the dimming area in the display element 71 increases, that is, the area of the dimming area in which the transmittance is reduced. It is preferable to make it large. Thereby, even if the brightness outside the vehicle 1 changes, it is possible to ensure the visibility of the display element 71 of the driver 5.

  Note that, as described above, reducing the transmittance of the light control region 72, as shown in FIG. 3, the liquid crystal layer 44, and the first transparent conductive film 42 laminated so as to sandwich the liquid crystal layer 44, and Although it is realized by the second transparent conductive film 43, the present invention is not limited to this. That is, any structure may be adopted as long as the transmittance of the light control region 72 in the combiner 30 is reduced.

  FIG. 7 is a diagram illustrating a display example of an image in the daytime of the entire combiner according to the first embodiment. A display example of an image projected (displayed) on the combiner 30 of the present embodiment in the daytime will be described with reference to FIG.

  The amount of external light incident on the combiner 30 from the outside of the windshield 2a is larger in the daytime than in the nighttime. Therefore, as described above, the dimming control unit 20 reduces the transmittance of the dimming area having a larger area than the area of the display element in the dimming film 32 than the transmittance of the portion around the dimming area. . Specifically, the dimming control unit 20 includes the first electrode driving unit 21a and the first transparent electrode 42b and the second transparent electrode 43b corresponding to the matrix-shaped intersections included in the dimming region of the dimming film 32. The drive voltage applied via the second electrode drive unit 21b is adjusted to reduce the transmittance of the dimming region. Whether or not the dimming control unit 20 decreases the transmittance of the dimming region depends on whether the illuminance detected by the illuminance sensor 22 received by the control unit 17 via the data input unit 14 is a predetermined threshold value or more. It may be determined based on whether or not.

  As shown in FIG. 7, the combiner 30 displays a direction display element 51, a spot display element 52, a scheduled time display element 53, and a lane display element 54 by the image projected from the projection device 10, as in FIG. 5. ing. Furthermore, the dimming control unit 20 lowers the transmittance of the dimming area having a larger area than the area of each display element in the dimming film 32 of the combiner 30 than the transmittance of the portion around the dimming area. . Specifically, the dimming control unit 20 lowers the transmittance of the direction display dimming area 101 having a larger area than the area of the direction display element 51 than the transmittance of the portion around the direction display dimming area 101. I am letting. As a result, the direction display element 51 is displayed as if it is bordered by the direction display dimming region 101 with reduced transmittance.

  Similarly, the dimming control unit 20 has a point display dimming area 102, a time display dimming area 103, and a lane display that are wider than the areas of the point display element 52, the scheduled time display element 53, and the lane display element 54. The transmittance of the light control region 104 is made lower than the transmittance of the portion around each light control region. As a result, the point display element 52, the scheduled time display element 53, and the lane display element 54 are bordered by the point display dimming area 102, the time display dimming area 103, and the lane display dimming area 104 that have reduced transmittance, respectively. Is displayed.

  As described above, the image display apparatus 300 according to the present embodiment projects the display element on the light control region after reducing the transmittance of the light control region having an area larger than the area of the display element displayed on the combiner. Therefore, the display area is displayed as if it is bordered by the dimming area having reduced transmittance. As a result, the display element is displayed on the dimming area that appears to be dark for the driver due to a decrease in transmittance, and the display element is displayed as bordered by the dimming area. The visibility with respect to an element can be improved. However, when reducing the transmittance in the dimming area, it is not necessary to completely block the external light, but only to a certain extent that the external light is transmitted, so that the field of view through the dimming area is secured. preferable. Thereby, outside light is completely blocked in the dimming area, and it is possible to suppress troubles in driving by the driver due to the view being blocked by the dimming area.

  In addition, since the image display device 300 displays the display element on the light control region where the transmittance is lowered and looks dark to the driver, it is not necessary to display the display element with a light amount larger than the light amount of the external light. Thereby, since it is not necessary to display the display element brighter than the external light, the power consumption of the image display device 300 can be suppressed.

  In addition, as the illuminance outside the vehicle detected by the illuminance sensor increases, it is preferable to increase the border width of the dimming area on the display element, that is, to increase the area of the dimming area with reduced transmittance. is there. Thereby, even if the brightness outside the vehicle changes, it becomes possible to ensure the visibility of the display elements of the driver.

  Note that the transmittance of the dimming area having a larger area than the area of the display element displayed on the combiner is lowered, the display element is projected onto the dimming area, and the display element is trimmed by the dimming area having a reduced transmittance. However, the display is not limited to this. That is, in the light control film 32, it is good also as what does not reduce the transmittance | permeability of the area | region of an area larger than the area of a display element, but reduces the transmittance | permeability of the area | region of the part which borders a display element. Thereby, as described above, it is possible to display the display element as if it is outlined by the light control area, and it is possible to improve the visibility of the display element of the driver and to correspond to the display area of the light control film. Since the transmittance | permeability has not fallen in the part, the trouble to a driver | operator's driving | operation can be suppressed. As described above, when the area of the portion bordering the display element is a dimming area, the transmittance is gradually decreased from the outer peripheral edge of the dimming area toward the inner peripheral edge. Good. In addition, it is preferable that the peripheral edge of the display element is projected so as to coincide with the inner peripheral edge of the dimming area, but the peripheral edge of the display element slightly deviates from the inner peripheral edge of the dimming area. Cases are also envisaged. However, even in such a case, the function of displaying the display element as if it was outlined as described above is not erased, and the driver's visibility with respect to the display element can be ensured.

  For example, when the display element is small, or when the display element is a character or symbol, etc., the transmittance of the dimming area with a larger area than the area of the display element displayed on the combiner is reduced, and the display element is large Alternatively, when the display element is a graphic or the like, the transmittance of the area that borders the display element displayed on the combiner may be reduced. In this case, the determination of whether the display element is small or large may be made by determining the area of the display element using a predetermined threshold value, or may be determined in advance. As a result, when the display element is small, even if the transmittance of the dimming area including the display element portion is reduced, there is almost no hindrance to the driving of the driver, and the dimming control is not performed. It becomes simple. Further, when the display element is a character or a symbol, the visibility of the display element can be further improved by reducing the transmittance of the dimming region including the display element portion, and the driver's Recognition of the display element can be facilitated. Furthermore, when the display element is large, or when the display element is a graphic or the like, as described above, the driver's visibility with respect to the display element can be improved, and the portion corresponding to the display area of the light control film has a transmittance. Since it does not decrease, it is possible to suppress troubles for the driver.

  Moreover, although the light control film 32 which can control the transmittance | permeability was stuck on the transparent plate 31, and it was set as the separate body from the windshield 2a as the combiner 30, it is not limited to this. For example, the light control film 32 may be attached to the windshield 2a instead of the transparent plate 31. Further, the light control film 32 may be embedded in the windshield 2a.

<Modification>
FIG. 8 is a diagram illustrating an example of a state in which the image display device according to the modified example of the first embodiment is mounted on a vehicle. With reference to FIG. 8, an example of mounting the image display device according to the present modification on a vehicle will be described.

  As shown in FIG. 8, the image display apparatus according to this modification includes a projection apparatus 10a, a combiner 30a, and a reflection plate 80.

  In FIG. 1, the projection device 10 is assumed to be installed above the driver 5 in the passenger compartment 3, which is the room space of the vehicle body 2 of the vehicle 1. The head-up display device, like a conventional car navigation device, reduces obstacles to driving by removing the line of sight from the field of view of the driver 5 through the windshield 2a and moving the line of sight to the screen of the car navigation device. It is. Therefore, if the combiner of the image display device is installed at a position that covers a part of the field of view of the vehicle body 2 through the windshield 2a, the driver 5 will not take his line of sight out of the field of view through the windshield 2a. .

  As shown in FIG. 8, the combiner 30a of this modification is installed below the windshield 2a of the vehicle body 2 (dashboard 4 side), and covers a part of the field of view of the driver 5 over the windshield 2a. is set up. The projection device 10 a is installed in the dashboard 4.

  Projection light 201 a including an image projected from the projection device 10 a is reflected as primary reflected light 202 a by the reflector 80 installed in the dashboard 4. The primary reflected light 202a is reflected by the combiner 30a, and the secondary reflected light 202b enters the eyes of the driver 5. As a result, the driver 5 visually recognizes that the image (virtual image 221a) is displayed at a predetermined distance (for example, 2 to 4 [m] or the like) first in the visual field 211a through the combiner 30a.

  The operations of the projection apparatus 10a and the combiner 30a according to this modification are the same as those of the projection apparatus 10 and the combiner 30 according to the first embodiment.

(Second Embodiment)
The image display apparatus according to the second embodiment will be described focusing on differences from the configuration and operation of the image display apparatus 300 according to the first embodiment. In this embodiment, instead of sticking the light control film 32 having the liquid crystal layer 44 to the transparent plate 31 like the combiner 30 of the first embodiment, the light control having the light control layer 94 described later on the transparent plate. A film 32a is affixed to form a combiner. The image display device according to the present embodiment is the same as the configuration of the image display device 300 according to the first embodiment except for the configuration of the light control film 32 a having the light control layer 94.

<Structure of light control film>
FIG. 9 is a diagram illustrating a structure example of a light control film according to the second embodiment. The structure of the light control film 32a will be described with reference to FIG.

  The combiner according to the present embodiment has a structure in which the surface of one side of a transparent plate (not shown) of glass or transparent resin that transmits light is covered with a light control film 32a.

  As shown in FIG. 9, the light control film 32a includes a first film 91a, a first transparent conductive film 92 (first transparent film), a light control layer 94, a second transparent conductive film 93 (second transparent film), a first film. Two films 91b are stacked in this order.

  The first film 91a and the second film 91b correspond to the first film 41a and the second film 41b of the first embodiment, respectively, and may have the same configuration.

  The first transparent conductive film 92 and the second transparent conductive film 93 correspond to the first transparent conductive film 42 and the second transparent conductive film 43 of the first embodiment, respectively, and may have the same configuration. . That is, the first transparent conductive film 92 has a plurality of first transparent electrodes (not shown) arranged in parallel in a stripe shape. The second transparent conductive film 93 has a plurality of second transparent electrodes (not shown) arranged in a stripe shape in a direction crossing the first transparent electrode.

  The light control layer 94 has a structure in which a light control mirror layer 95, a catalyst layer 96, an electrolyte layer 97, and an ion layer 98 are stacked from the first transparent conductive film 92 toward the second transparent conductive film 93.

  The ion layer 98 is a layer that stores, for example, hydrogen ions. The dimming mirror layer 95 is formed of a metal material, and is a mirror state layer having high light reflectance (low transmittance) in a normal state. The catalyst layer 96 is a layer that promotes a chemical reaction that occurs when hydrogen ions stored in the ion layer 98 move to the dimming mirror layer 95 via the electrolyte layer 97.

  When a drive voltage is applied between the first transparent conductive film 92 and the second transparent conductive film 93 such that hydrogen ions move toward the dimming mirror layer 95, the dimming mirror layer 95 is moved from the ion layer 98. The hydrogen ions that have migrated to cause a chemical reaction and turn into metal hydrides. The produced metal hydride is a transparent material having high light transmittance (low reflectance). Since this state change is a reversible change, when the drive voltage applied between the first transparent conductive film 92 and the second transparent conductive film 93 is applied with the polarity reversed, the metal in the light control mirror layer 95 is applied. Hydrogen ions are desorbed from the hydride. As a result, the dimming mirror layer 95 returns to the original metallic material and becomes a mirror state with high light reflectance (low transmittance).

  In this way, the dimming control unit 20 (not shown) is driven by the polarity of the drive voltage via the first electrode drive unit 21a and the second electrode drive unit 21b (each not shown) according to the principle of electrochromism. By controlling the size, the light reflectance (transmittance) of the light control film 32a can be controlled.

<Light transmission operation in the light control layer>
FIG. 10 is a diagram for explaining a change in reflectance of the light control layer according to the second embodiment. With reference to FIG. 10, the light reflecting operation in the case where an electric field is formed in the light control layer 94 and in the case where an electric field is not formed will be described.

  FIG. 10A shows a case where a predetermined drive voltage is applied between the first transparent conductive film 92 and the second transparent conductive film 93 so that hydrogen ions move toward the dimming mirror layer 95. It is a figure which shows the behavior of the incident light 61a. A drive voltage having a predetermined magnitude is applied between the first transparent conductive film 92 and the second transparent conductive film 93, and an electric field proportional to the drive voltage is formed in the light control layer 94. Metal hydride is generated in the mirror layer 95, and has low light reflectance (high transmittance). In this state, the incident light 61a incident on the dimming layer 94 is mostly transmitted light 62a that is transmitted through the dimming layer 94 from a surface opposite to the surface of the dimming layer 94 on which the incident light 61a is incident. Exit. Further, a part of the incident light 61a is reflected by the light control layer 94 as reflected light 63a on the same side as the surface of the light control layer 94 on which the incident light 61a is incident.

  FIG. 10B shows incident light when a predetermined voltage is applied between the first transparent conductive film 92 and the second transparent conductive film 93 so that hydrogen ions are desorbed from the dimming mirror layer 95. It is a figure which shows the behavior of 61a. Between the first transparent conductive film 92 and the second transparent conductive film 93, a driving voltage having a polarity reversed from that in the case of FIG. 10A is applied, and an electric field proportional to the driving voltage is applied to the light control layer 94. Since hydrogen ions are desorbed in the light control mirror layer 95, the light reflectance (lower transmittance) is higher than in the case of FIG. In this state, among the incident light 61a incident on the light control layer 94, the transmitted light 64a having a light amount smaller than the transmitted light 62a is emitted from the surface opposite to the surface of the light control layer 94 on which the incident light 61a is incident. To do. Further, a part of the incident light 61a is reflected by the dimming layer 94 as reflected light 65a having a larger light quantity than the reflected light 63a on the same side as the surface of the dimming layer 94 on which the incident light 61a is incident.

  In FIG. 10, the behavior of the transmitted light and the reflected light of the incident light 61 a by the electric field formed in the light control layer 94 is schematically described. The amount of transmitted light and reflected light can be controlled.

  Even by using the light control layer 94 having the structure and properties as described above, the projection operation of the image onto the combiner and the control of the transmittance of the light control region in the light control layer 94 as described in the first embodiment. Is possible. Therefore, the effect of the first embodiment can be obtained also by using the light control layer 94 of the present embodiment instead of the liquid crystal layer 44 in the first embodiment.

(Third embodiment)
The image display apparatus according to the third embodiment will be described focusing on differences from the configuration and operation of the image display apparatus 300 according to the first embodiment. In the present embodiment, as in the combiner 30 of the first embodiment, the portions of the light control film 32 corresponding to the matrix-like intersections can be controlled independently of the light transmittance in advance. The light transmittance can be controlled in the specified region. The image display device according to the present embodiment is the same as the configuration of the image display device 300 according to the first embodiment except for the configuration of the light control film.

<Configuration of light control film>
FIG. 11: is a structural example of the light control area | region in the light control film of the combiner which concerns on 3rd Embodiment. The configuration of the light control film 32b of the combiner 30b will be described with reference to FIG.

  In the first embodiment, as described above, the first transparent conductive film 42 is configured by arranging a plurality of first transparent electrodes 42b in parallel on the first glass substrate 42a. The second transparent conductive film 43 is configured by arranging a plurality of second transparent electrodes 43b in a stripe shape in parallel with the first transparent electrode 42b on the second glass substrate 43a. By adopting such a configuration of the first transparent electrode 42b and the second transparent electrode 43b, the points (intersections) at which the electrodes intersect can be arranged in a matrix, and adjustments corresponding to the respective intersections in the matrix are possible. The portions of the optical film 32 can control the light transmittance independently of each other.

  On the other hand, the light control film 32b of the combiner 30b of this embodiment arrange | positions a transparent electrode only in the specific area | region in the 1st transparent conductive film 42 and the 2nd transparent conductive film 43 (not shown). . The transparent electrodes arranged in these specific regions are electrically connected to the first electrode driving unit 21a and the second electrode driving unit 21b (not shown) for each transparent electrode. That is, the light transmittance can be controlled for each specific region of the light control film 32b.

  As specific areas (light control areas) in the light control film 32b, specifically, as shown in FIG. 11, direction display light control areas 111a to 111f, a first light control area 112, a second light control area 113, and A third light control region 114 is configured. That is, the light control film 32b is preliminarily configured with a light control region pattern. In each of the light control regions, a transparent electrode is disposed on both the first transparent conductive film 42 and the second transparent conductive film 43 in accordance with the shape of the region. The dimming control unit 20 (not shown) is applied to the transparent electrode of the first transparent conductive film 42 and the transparent electrode of the second transparent conductive film 43 via the first electrode driving unit 21a and the second electrode driving unit 21b. The transmittance of each dimming region is controlled by adjusting the driving voltage.

<Image to be projected onto combiner>
FIG. 12 is a diagram illustrating a display example of an image of the entire combiner according to the third embodiment. A display example of an image projected (displayed) on the combiner 30b of the present embodiment will be described with reference to FIG.

  The amount of external light that enters the combiner 30b from the outside of the windshield 2a (not shown) is larger in the daytime than in the nighttime. Therefore, the dimming control unit 20 determines the transmittance of the above dimming area having a larger area than the area of the display element at a specific position where the display element is displayed on the dimming film 32b. The transmittance of the portion is reduced.

  As shown in FIG. 12, the combiner 30b includes a direction display element 51 indicating a left direction, a point display element 52, a scheduled time display element 53, and a lane display element 54 based on an image projected from the projection device 10 (not shown). Is displayed. And the light control part 20 has the area wider than the area | region of each display element in the light control film 32b of the combiner 30b, and also has the transmittance | permeability of the light control area comprised in the specific area | region as a light control area. Lower than the transmittance of the surrounding area. Specifically, the dimming control unit 20 reduces the transmittance of the dimming region in which the direction display dimming regions 111b, 111d, and 111f having a larger area than the region of the direction display element 51 are combined. As a result, the direction display element 51 is displayed as bordered by the dimming area that combines the direction display dimming areas 111b, 111d, and 111f with reduced transmittance.

  Although the direction display element 51 has been described as a display element indicating the left direction, when the direction display element 51 is a display element indicating the right direction, the dimming control unit 20 includes the direction display dimming region 111c, What is necessary is just to reduce the transmittance | permeability of the light control area | region which combined 111e and 111f. Further, when the direction display element 51 is a display element indicating a straight traveling direction, the dimming control unit 20 may reduce the transmittance of the dimming area including the direction display dimming areas 111a, 111d, 111e, and 111f. Good. In any case, the direction display element 51 is displayed as if it is bordered by the dimming region having a reduced transmittance.

  Similarly, the dimming control unit 20 includes a first dimming area 112, a second dimming area 113, and a third dimming area that are wider than the areas of the point display element 52, the scheduled time display element 53, and the lane display element 54, respectively. The transmittance of the dimming area 114 is lowered to the transmittance of each dimming area. As a result, the spot display element 52, the scheduled time display element 53, and the lane display element 54 are bordered by the first dimming area 112, the second dimming area 113, and the third dimming area 114, which have reduced transmittance, respectively. Is displayed.

  As in the above configuration, unlike the first embodiment, the transparent electrode is arranged only in the light control region configured in advance with a specific pattern of the light control film 32b according to the shape of the light control region. It is said. Thus, unlike the first embodiment, it is not necessary to dispose a transparent electrode on the entire light control film, and it is only necessary to provide a specific light control region, thereby reducing the cost of manufacturing the light control film. can do. In addition, the light control operation in each light control region of the light control film 32b can be easily controlled.

  In addition, the display element is projected onto the dimming area after reducing the transmittance of the dimming area that is larger than the area of the display element displayed on the combiner. Display as if bordered by region. As a result, the display element is displayed on the dimming area that appears to be dark for the driver due to a decrease in transmittance, and the display element is displayed as bordered by the dimming area. The visibility with respect to an element can be improved. However, when reducing the transmittance in the dimming area, it is not necessary to completely block the external light, but only to a certain extent that the external light is transmitted, so that the field of view through the dimming area is secured. preferable. Thereby, outside light is completely blocked in the dimming area, and it is possible to suppress troubles in driving by the driver due to the view being blocked by the dimming area.

  Further, since the image display device 300 displays the display element in the light control region where the transmittance decreases and the driver looks dark, it is necessary to display the display element with a light amount 1.5 times larger than the amount of ambient light. However, even if the amount of light is about 1 to 1.2 times, sufficient visibility can be obtained. As a result, the amounts of ambient light and image light do not differ greatly, and the display element does not give glare to the driver. In addition, since the display element can be projected with lower brightness than in the prior art, the power consumption of the image display device can be suppressed.

  In addition, it is also possible to apply the light control film 32b of this embodiment to the image display apparatus which concerns on the above-mentioned 2nd Embodiment.

  Moreover, although the image display apparatus according to the above-described embodiment has been described as being mounted on a vehicle, the present invention is not limited to this, and can be mounted on a train, an aircraft, and the like.

DESCRIPTION OF SYMBOLS 1 Vehicle 2 Car body 2a Windshield 3 Cabin 4 Dashboard 5 Driver 10, 10a Projector 11 Radio wave receiving part 12 Positioning part 13 Operation input part 14 Data input part 15 Wireless communication part 16 Storage part 17 Control part 18 Image generation part DESCRIPTION OF SYMBOLS 19 Projection part 20 Light control part 21a 1st electrode drive part 21b 2nd electrode drive part 22 Illuminance sensor 30, 30a, 30b Combiner 31 Transparent board 32, 32a, 32b Light control film 41a 1st film 41b 2nd film 42 2nd 1 transparent conductive film 42a first glass substrate 42b first transparent electrode 43 second transparent conductive film 43a second glass substrate 43b second transparent electrode 44 liquid crystal layer 44a liquid crystal 51 direction display element 52 point display element 53 scheduled time display element 54 lane Display element 61, 61a Incident light 62, 62a Transmitted light 63, 6 a Reflected light 64, 64a Transmitted light 65, 65a Reflected light 71 Display element 72, 72a Light control area 80 Reflector 91a First film 91b Second film 92 First transparent conductive film 93 Second transparent conductive film 94 Light control layer 95 Light control mirror layer 96 Catalyst layer 97 Electrolyte layer 98 Ion layer 101 Direction display light control region 102 Point display light control region 103 Time display light control region 104 Lane display light control region 111a to 111f Direction display light control region 112 First light control Area 113 Second dimming area 114 Third dimming area 201, 201a Projected light 202 Reflected light 202a Primary reflected light 202b Secondary reflected light 211, 211a Field of view 221, 221a Virtual image 300 Image display device

Claims (13)

A screen including a light control layer capable of controlling the transmittance for each region;
A projection unit that projects and displays an image on the screen;
At least the transmittance of the light control region, which is the region of the light control layer corresponding to the peripheral portion of the display element included in the image displayed on the screen, is lower than the transmittance of the outer portion of the light control region A dimming control unit for performing dimming control;
An image display device comprising:   The image display device according to claim 1, wherein the dimming control unit lowers the transmittance of the dimming region having an area larger than the area of the display element from the transmittance of an outer portion of the dimming region.   The image display device according to claim 1, wherein the dimming control unit reduces the transmittance of the dimming region in the peripheral portion of the display element to be lower than the transmittance of an outer portion of the dimming region. The dimming controller is
When the area of the display element is smaller than a predetermined threshold, the transmittance of the dimming region having a larger area than the area of the display element is reduced from the transmittance of the outer portion of the dimming region,
2. The image according to claim 1, wherein when the area of the display element is larger than the predetermined threshold, the transmittance of the light control region in the peripheral portion of the display element is lowered than the transmittance of an outer portion of the light control region. Display device. The dimming controller is
When the display element is a character, the transmittance of the dimming region having a larger area than the area of the display element is reduced from the transmittance of the outer portion of the dimming region,
2. The image display device according to claim 1, wherein when the display element is a graphic, the transmittance of the dimming region in the peripheral portion of the display element is made lower than the transmittance of the outer portion of the dimming region.   6. The light control unit according to claim 1, wherein, in the light control region, the light control unit gradually decreases the transmittance from a peripheral portion outside the light control region toward a peripheral portion outside the display element. The image display device according to item. The light control layer can control the transmittance for each region divided in a matrix,
When the image including the display element is projected on the screen, the dimming control unit determines the transmittance of the region divided into the matrix corresponding to the dimming region as an outer portion of the dimming region. The image display device according to any one of claims 1 to 6, wherein the image display device is made lower than the transmittance. The light control layer can control the transmittance with the light control region as a region corresponding to a specific display element displayed on the screen,
When the image including the specific display element is projected on the screen, the dimming control unit determines the transmittance of the dimming area corresponding to the specific display element in the outer portion of the dimming area. The image display device according to claim 1, wherein the image display device is made lower than the transmittance. An illuminance detector that detects the illuminance around the screen;
The image display device according to claim 1, wherein the dimming control unit performs the dimming control when the illuminance is equal to or greater than a predetermined threshold.   The image display device according to claim 9, wherein the dimming control unit expands the dimming region toward the outside of the display element as the illuminance increases.   The image display device according to claim 9, wherein the dimming control unit does not execute the dimming control when the illuminance is less than the predetermined threshold. A first transparent film having a first transparent electrode;
A second transparent film having a second transparent electrode;
A light control layer that is disposed between the first transparent film and the second transparent film, and whose transmittance varies according to a driving voltage applied between the first transparent electrode and the second transparent electrode. When,
With
The first transparent electrode and the second transparent electrode are at least a screen disposed in a light control region that is a part of a light control layer around a specific display element of an image projected by a projection device. Projecting and displaying an image on a screen including a light control layer whose transmittance can be controlled for each region; and
At least the transmittance of the light control region, which is the region of the light control layer corresponding to the peripheral portion of the display element included in the image displayed on the screen, is lower than the transmittance of the outer portion of the light control region Steps,
An image display method comprising: