JP5811747B2 - Head mounted display - Google Patents

Description

  The present invention relates to a head-mounted display that presents a content image to a user who wears it in a visually recognizable manner.

  2. Description of the Related Art Conventionally, there is known a head mounted display that allows a user to recognize a content image by presenting the content image so as to be visible to the user's eyes. For example, Patent Document 1 discloses a virtual image display type information display system. The virtual image display type information display system includes an image display unit and a transflective optical element. The transflective optical element reflects part of the light from the image display unit and transmits the remaining image light. Part of the light from the image display unit is reflected by the transflective optical element and enters the user's eyes. The user visually recognizes image information formed by the reflected light.

  The transflective optical element transmits external light from the outside in the viewing direction of the user. As a result, the user can also visually recognize the view direction through the transflective optical element. Due to this transmission configuration, the transflective optical element also transmits light emitted from the image display unit. In this case, when there is another user in the emission direction, there is a possibility that the other user can recognize the image information formed by the transmitted light transmitted through the transflective optical element. As a result, for example, when the image information is confidential information, the confidential information may be known to other users.

JP 2006-201611 A

  In order to prevent leakage of image information to other users, Patent Document 1 discloses the following technique. A first polarizing filter that transmits light in the first polarization state is attached to the image display unit, and a second polarizing filter that transmits light in a second polarization state different from the first polarization state is a transflective optical Affixed to the element. Since the second polarization filter transmits light in the second polarization state out of external light from the outside, the reduced external light enters the user's eyes. Therefore, the user may recognize that the outside world is darker than it actually is.

  Patent Document 1 discloses a technique in which a display unit side louver optical element is provided in an image display unit. In this technique, the display unit side louver optical element limits the viewing angle of the image display unit. Therefore, the user may not be able to clearly recognize the image information formed by the reflected light from the transflective optical element.

  Patent Document 1 discloses a technique in which the second louver-like optical element is provided on the surface opposite to the image display unit of the transflective optical element. The second louver-like optical element has a louver whose lateral direction is substantially parallel to the user's line-of-sight direction. This louver substantially parallel to the user's line-of-sight direction blocks outside light from the different direction when the user changes the line-of-sight direction. As a result, the user's field of view may be narrowed.

  The present invention is a head capable of reducing external light and dimming of light forming image information while reducing the possibility that image information formed by light from an image display unit leaks to other users. To provide a mount display.

の条件を満たす下限角θｍ以上、かつ９０度未満であることを特徴とするものである。
In order to achieve this object, the head mounted display according to claim 1 is attached to a frame to be worn on a user's head, and image light based on image information is incident on the user's eyes, thereby Is a head-mounted display that is recognized by a user, and includes a generation unit that generates image light in which the image becomes a virtual image, and a half mirror disposed in the field of view of the user, A first surface that reflects part of the image light generated by the generation unit in the direction of the user's eyes, and an incident angle of transmitted light that is the other part of the image light that has passed through the first surface is near a critical angle. And the second surface is inclined at a predetermined angle with respect to the first surface so as to totally reflect the transmitted light, and the material of the half mirror has a refractive index n. The first surface is Is image light is disposed at a position where the incident angle alpha, the second surface, the first surface with respect to, inclined at an inclination angle theta, the angle of inclination theta is

The lower limit angle θm that satisfies the above condition is less than 90 degrees and less than 90 degrees .

In order to achieve this object, the head mounted display according to claim 2 is attached to a frame to be worn on a user's head, and image light based on image information is incident on the user's eyes, thereby Is a head-mounted display that is recognized by a user, and includes a generation unit that generates image light in which the image becomes a virtual image, and a half mirror that is disposed in the field of view of the user, and the half mirror includes the generation A first surface that reflects a part of the image light generated by the unit in the direction of the user's eye, and the image light that is inclined at a predetermined angle with respect to the first surface and transmitted through the first surface. And a second surface having an incident angle of transmitted light that is the other part near the critical angle, and the second surface is inclined at a predetermined angle with respect to the first surface so as to totally reflect the transmitted light. The half mirror is Disposed within the field of view of the user's eye, the second surface, is characterized in that the total reflected light reflected at the second surface are disposed such that between the eyes of the user .

In order to achieve this object, the head mounted display according to claim 3 is attached to a frame to be worn on a user's head, and image light based on image information is incident on the user's eyes, thereby Is a head-mounted display that is recognized by a user, and includes a generation unit that generates image light in which the image becomes a virtual image, and a half mirror disposed in the field of view of the user, A first surface that reflects a part of the image light generated by the generation unit in the direction of the eyes of the user, and the image light that is inclined at a predetermined angle with respect to the first surface and transmitted through the first surface And a second surface having an incident angle of transmitted light in the vicinity of a critical angle, which is the other part, and the second surface intersects the first surface on the generation unit side .

  According to the head mounted display of the first aspect, the incident angle of the transmitted light is close to the critical angle. As a result, the transmitted light transmitted through the first surface and incident on the second surface is refracted or totally reflected on the second surface. The traveling direction of the transmitted light that is refracted or totally reflected on the second surface is closer to the user side than the traveling direction of the image light generated by the generating unit. Thereby, the possibility that the transmitted light refracted or totally reflected on the second surface is incident on the eyes of other users positioned in the traveling direction of the image light generated by the generation unit is reduced. Further, the half mirror does not include a configuration such as a louver or a polarizing filter that blocks the image light generated by the generation unit and the external light incident from the second surface side. As a result, dimming of image light and external light generated by the generator that enters the eyes of the user wearing the head-mounted display can be suppressed. Therefore, it is possible to suppress external light and dimming of the image light forming the image while reducing the possibility of the image leaking to other users in the traveling direction of the image light generated in the generation unit.

Also, the second surface is inclined at a predetermined angle with respect to the first surface transmitted light to the total reflection. The reflected light totally reflected on the second surface is directed to the user wearing the head mounted display. As a result, a part of the transmitted light transmitted through the first surface is totally reflected on the second surface, and the image light is incident on the region where the face of the user wearing the head mounted display is located. Therefore, when the image light is incident on a region where the user's face is partly transmitted through the first surface, the risk of the image leaking to other users is reduced, and the external light and the image are reduced. Dimming of image light to be formed can be suppressed.

Further, the second surface is inclined with respect to the first surface at an inclination angle θ that is not less than the lower limit angle θm and less than 90 °. The lower limit angle θm is the minimum angle at which the light incident on the second surface is totally reflected. Thereby, the light transmitted through the first surface at the incident angle α is totally reflected on the second surface. On the second surface, the totally reflected reflected light travels toward the user wearing the head mounted display. As a result, a part of the transmitted light transmitted through the first surface is totally reflected on the second surface, and the image light is incident on the face of the user wearing the head mounted display. Therefore, when the image light is incident on a region where the user's face is partly transmitted through the first surface, the risk of the image leaking to other users is reduced, and the external light and the image are reduced. Dimming of image light to be formed can be suppressed.

Also, the second surface being arranged such that all the reflected light reflected at the second surface faces between the user's eyes. As a result, part of the transmitted light that has passed through the first surface is totally reflected on the second surface, and the formation of an image on the other eye can be reduced. Therefore, since the image is not formed on the other eye, the user can easily visually recognize the outside world with the other eye.

In addition, the second surface intersects the first surface on the generation unit side. Thereby, the thickness of a half mirror becomes thinner than the half mirror which has a 2nd surface which does not cross | intersect a 1st surface. As the thickness of the half mirror increases, the optical path of external light from the outside in the half mirror becomes longer. Light passing through the second surface from the outside is refracted on the second surface. Since the optical path becomes longer in the refracted direction, the external environment recognized by the user by the external light incident on the user's eyes is displaced from the actual external environment by the thickness of the half mirror. Since the thickness of the half mirror having the second surface intersecting with the first surface on the generation side becomes thin, the user recognizes the outside world close to the actual outside world. Therefore, when the second surface intersects with the first surface, the user can recognize the outside world in which positional deviation is suppressed as compared with the half mirror in which the second surface does not intersect with the first surface.

It is a perspective view which shows the external appearance of HMD1 in one Embodiment of this invention. FIG. 3 is an enlarged perspective view of a generation unit 10. It is sectional drawing of the generation | occurrence | production part 10 which follows the AA line of the arrow shown in FIG. FIG. 3 is a diagram showing the shape of the half mirror 20 and the optical path of image light generated from the generation unit 10. FIG. 6 is an optical path diagram when light totally reflected on the second surface 22 enters the right eye RE. It is the enlarged view to which the half mirror 20 vicinity in FIG. 5 was expanded. It is an optical path diagram which shows the optical path which external light permeate | transmits the inside of the half mirror 20, and injects into the user's one eye wearing HMD1.

  An embodiment of the present invention will be described with reference to FIGS. In the following description, the head-mounted display is described as HMD (Head Mounted Display).

[Overview of HMD1]
The HMD 1 will be described with reference to FIG. FIG. 1 is a perspective view showing the appearance of the HMD 1. The HMD 1 includes a head mounting unit 2 and a generation unit 10. The head mounting part 2 is mounted on the user's head. In the present embodiment, the user wears the HMD 1 in the atmosphere. The head mounting part 2 is an example of the frame of the present invention.

  The head mounting part 2 is demonstrated using FIG. The skeleton of the head mounting unit 2 serves as a mounting unit that is mounted on the user's head. The skeleton of the head mounting portion 2 includes temples 3A and 3B, armor 4A and 4B, and a front frame 5. Modern 6A, 6B which hits a user's ear is attached to one end of temples 3A, 3B. The other ends of the temples 3A and 3B are connected to the arms 4A and 4B via hinges 7A and 7B. The armatures 4A and 4B are connected to the left and right ends of the front frame 5. A nose pad 8 that contacts the user's nose is provided in the center of the front frame 5. The temples 3A and 3B can be folded with respect to the front frame 5 by hinges 7A and 7B formed on the arms 4A and 4B. The structure of the skeleton of the head mounting part 2 is the same as that of normal glasses, for example. The head mounting portion 2 is held on the user's head by the modern 6A, 6B and the nose pad 8 when the head is mounted on the user. In FIG. 1, illustration of the armor 4B and the hinge 7B is omitted.

  The generation unit 10 presents the image to the user's one eye so as to be visible. The generation unit 10 is held by the skeleton of the head mounting unit 2 via the attachment unit 9 disposed in the vicinity of the armor 4B. The generation unit 10 is disposed at a position that is substantially the same height as the left eye LE of the user wearing the head mounting unit 2 when attached to the skeleton of the head mounting unit 2.

  The generator 10 will be described with reference to FIGS. 2 and 3. FIG. 2 is an enlarged perspective view of the generator 10. FIG. 3 is a cross-sectional view of the generator 10 taken along the line AA of the arrow shown in FIG. The generation unit 10 emits image light based on various signals transmitted from a control box (not shown) via a cable toward the half mirror 20. Various signals are signals based on image information. Specifically, as illustrated in FIG. 3, the generation unit 10 includes an LCD (Liquid Crystal Display) 11 and a lens system 12. The half mirror 20 is fixed to the generation unit 10 at the end of the generation unit 10 opposite to the LCD 11. In this fixed state, the half mirror 20 is disposed within the field of view of the user wearing the HMD 1. The LCD 11 generates image light. The generated image light passes through the lens system 12 and enters the half mirror 20. The half mirror 20 reflects a part of the image light generated in the generation unit 10 and guides it to the left eye LE of the user. Thereby, the user recognizes the content image. The generation unit 10 generates image light so that the content image recognized by the user wearing the HMD 1 becomes the virtual image VI. The half mirror 20 transmits a part of the external light representing the external image and guides it to the left eye LE of the user. That is, the user visually recognizes the image light superimposed on the external light. The LCD 11 may be composed of other two-dimensional image display elements such as an organic EL (Organic Electro-Luminescence) display. Alternatively, a well-known retinal scanning method that scans light in a two-dimensional direction, guides the scanned image light to the user's left eye LE, and forms a content image on the retina may be used instead of the LCD 11.

  The shape of the half mirror 20 will be described with reference to FIG. FIG. 4 is a diagram illustrating the shape of the half mirror 20 and the optical path of the image light generated from the generation unit 10. Although FIG. 4 shows the shape of the half mirror 20, it does not show the relative size relationship and the distance relationship between the generator 10 and the half mirror 20. The half mirror 20 includes a first surface 21 and a second surface 22. The first surface 21 is a surface on the generation unit 10 side. That is, the first surface 21 is the first surface that reflects the image light generated from the generator 10. The second surface 22 is inclined with respect to the first surface 21 at an inclination angle θ. A plane PL parallel to the first surface 21 is indicated by a two-dot chain line shown in FIG. 4. The normal line NL1 at the position where the image light of the first surface 21 is incident and the position where the image light of the second surface 22 is incident Normal lines NL2 at are indicated by broken lines, respectively. A solid line shown in FIG. 4 indicates collimated image light that passes through the center 13 of the lens system 12 among image light generated from the LCD 11. In the following description, the shape of the half mirror 20 will be described using an angle with respect to the collimated image light. The second surface 22 is inclined at an inclination angle θ with respect to the parallel surface PL. In a state where the second surface 22 is inclined, the distance between the first surface 21 and the second surface 22 becomes shorter on the generation unit 10 side. That is, the distance between the first surface 21 and the second surface 22 in the direction of the normal line NL1 of the first surface 21 becomes shorter as the generation unit 10 is approached. The inclination angle θ is an example of the predetermined angle of the present invention.

  The half mirror 20 is formed from a transparent resin material such as polycarbonate or acrylic resin. The refractive index n of polycarbonate is 1.585. The refractive index of the acrylic resin is 1.490. This refractive index is the absolute refractive index of each material. A reflective layer is formed on the first surface 21 of the half mirror 20 to reflect a part of the incident image light. Specifically, a metal such as aluminum is deposited on the first surface 21 so as to have a predetermined reflectance. The first surface 21 of the half mirror 20 on which the reflective layer is formed transmits the image light generated in the generation unit 10 through the first surface 21 and the reflected light incident on the left eye LE of the user wearing the HMD 1. It is divided into transmitted light.

  With reference to FIG. 4, the optical path of the image light generated from the generator 10 will be described. Image light generated from the LCD 11 fixed to the generation unit 10 passes through the lens system 12. The light that has passed through the center 13 of the lens system 12 is incident on the first surface 21 at the first incident angle α. The image light generated from the LCD 11 is divided into reflected light that is reflected by the first surface 21 and transmitted light that is transmitted through the first surface 21. The first incident angle α is an example of the incident angle α of the present invention.

  The reflected light reflected by the first surface 21 enters the user's left eye LE. With this incident light, the user recognizes the image.

In the first surface 21, the transmitted light that passes through the first surface 21 is refracted. Before and after transmitting through the first surface 21, the first incident angle α, the refraction angle β, and the refractive index n of the polycarbonate forming the half mirror 20, Snell's law is used (Equation 1-1). .

第２面２２は、第１面２１に対し、傾斜角θを有する。すなわち、第２入射角γ、屈折角β、および傾斜角θは（数１−３）の関係を有する。

第２入射角γが、本発明の透過光の入射角の一例である。 The transmitted light that passes through the inside of the half mirror 20 is totally reflected at the second surface 22. That is, the second incident angle γ when the transmitted light that has been transmitted through the first surface 21 and transmitted through the half mirror 20 is incident on the second surface 22 is equal to or greater than the critical angle. On the second surface 22, (Equation 1-2) is shown by the second incident angle γ and the refractive index n of the polycarbonate forming the half mirror.

The second surface 22 has an inclination angle θ with respect to the first surface 21. That is, the second incident angle γ, the refraction angle β, and the tilt angle θ have a relationship of (Equation 1-3).

The second incident angle γ is an example of the incident angle of the transmitted light according to the present invention.

ハーフミラー２０の第２面２２の傾斜角θは、（数１−４）の関係を満たす。（数１−４）の等号が成立する傾斜角θが、本発明の下限角θｍである。すなわち、第２面２２の傾斜角θは、（数１）の条件を満たす下限角θｍ以上である。

第２面２２が傾斜している状態において、第１面２１と第２面２２と距離が、発生部１０側において短くなることから、傾斜角θは、下限角θｍ以上、９０°未満である。 (Equation 1-4) is derived from (Equation 1-1), (Equation 1-2), and (Equation 1-3).

The inclination angle θ of the second surface 22 of the half mirror 20 satisfies the relationship of (Equation 1-4). The inclination angle θ at which the equal sign of (Equation 1-4) is established is the lower limit angle θm of the present invention. That is, the inclination angle θ of the second surface 22 is not less than the lower limit angle θm that satisfies the condition of (Equation 1).

In the state where the second surface 22 is inclined, the distance between the first surface 21 and the second surface 22 becomes shorter on the generation unit 10 side, so the inclination angle θ is not less than the lower limit angle θm and less than 90 °. .

  When the half mirror 20 is made of polycarbonate and the first incident angle α is 45 °, the lower limit θm is 13.1 °.

The reflected light totally reflected on the second surface 22 will be described. On the second surface 22, the totally reflected light is directed between the eyes of the user wearing the HMD 1. As a result, the reflected light totally reflected on the second surface 22 is incident on the eyes of another user, and the other users are less likely to recognize the image. Specifically, the tilt angle θc in the case where the totally reflected image light is incident on the right eye RE that is the other eye of the user wearing the HMD 1 will be described with reference to FIGS. 5 and 6. FIG. 5 is an optical path diagram when the light totally reflected on the second surface 22 enters the right eye RE. FIG. 6 is an enlarged view of the vicinity of the half mirror in FIG. 5 and 6 show the shape of the half mirror, but do not show the relative size relationship and the distance relationship between the generation unit 10 and the half mirror 20. The inclination angle θ when the reflected light totally reflected on the second surface 22 is directed between both eyes of the user wearing the HMD 1 is expressed by (Equation 2-1).

  The optical path of image light will be described using distance L1, distance L2, and distance L3. As shown in FIG. 5, the distance from the transmission point PA where the image light generated from the LCD 11 and passed through the center of the lens system 12 passes through the first mirror 21 to the inside of the half mirror 20 is the distance from the user's left eye LE. Distance L1. As shown in FIG. 6, the length in the direction of the normal line NL1 of the first surface 21 from the transmission point PA to the point PB of the second surface 22 is a distance L2. That is, the distance L2 is the thickness of the half mirror 20. As shown in FIG. 5, the distance between both eyes of the user wearing the HMD 1 is a distance L3. The transmitted light that has passed through and refracted the transmission point PA on the first surface 21 is totally reflected at the total reflection point PC of the second surface 22. The reflected light totally reflected at the total reflection point PC enters the right eye RE, which is the other eye of the user wearing the HMD 1.

As shown in FIG. 6, the distance Z1 connecting the transmission point PA and the total reflection point PC is formed by a line segment connecting the point PB and the transmission point PA and a line segment connecting the point PB and the total reflection point PC. The sine theorem was used from the angle and the angle formed by the line connecting the total reflection point PC and the transmission point PA and the line connecting the total reflection point PC and the point PB (Equation 2-2). It is.

5 and 6 show a straight line passing through the center 13 of the lens system 12 and the transmission point PA, and an intersection PD between the straight line and a perpendicular passing through the total reflection point PC. As shown in FIG. 6, the length X1 of the line connecting the transmission point PA and the intersection PD, the length Y1 of the line connecting the total reflection point PC and the intersection PD, the transmission point PA and the total reflection point PC. (Equation 2-3) is shown by the angle formed by the line segment connecting the transmission point PA and the total reflection point PC and the line segment connecting the transmission point PA and the intersection PD.

An angle δ formed by a line segment connecting total reflection point PC and right eye RE and a line segment connecting total reflection point PC and intersection PD shown in FIG. 6 connects total reflection point PC and transmission point PA. An angle formed by a line segment, a line segment connecting total reflection point PC and intersection PD, a line segment connecting total reflection point PC and transmission point PA, and a line segment connecting total reflection point and right eye RE (Equation 2-4) is shown by the angle formed by The derivation of (Equation 2-4) satisfies the relationship of (Equation 1-3).

As shown in FIG. 5, the distance L4 between the intersection PE between the line connecting the total reflection point PC and the intersection PD and the line segment connecting both eyes of the user and the other one eye RE of the user is an angle δ, From the length of the line segment connecting the total reflection point PC and the intersection PE, the three-square theorem is used (Expression 2-5). In the derivation of (Equation 2-5), the length of the line segment connecting the total reflection point PC and the intersection PE satisfies the relationship that is the sum of the distance Y1 and the distance L1.

As shown in (Expression 2-6), the distance L3 is the sum of the length of the line segment connecting the intersection PE and the user's left eye LE and the distance L4. The length of the line segment connecting the intersection PE and the user's one eye LE is X1 represented by (Equation 2-3).

From (Equation 2-1) to (Equation 2-6) described above, the inclination angle θc when the image light totally reflected on the second surface 22 is incident on the one eye RE of the user wearing the HMD 1 is (Equation 2). ).

  With reference to FIG. 7, the optical path from which the external light from the front direction of HMD1 permeate | transmits the inside of the half mirror 20, and injects into the left eye LE of the user who wears HMD1 is demonstrated. As shown in FIG. 7, the external light is incident on the second surface 22 at the third incident angle α1. In the following description, the optical path of external light that passes through the second surface 22 will be described.

The transmitted light that passes through the second surface 22 is refracted. Before and after transmitting through the second surface 22, (Equation 3-1) is expressed by the third incident angle α 1, the second refraction angle β 1, and the refractive index n of the polycarbonate forming the half mirror 20.

これは、図４に示すように、第１面２１と第２面２２との間における第１面２１の法線ＮＬ１の方向の長さが、発生部１０に近づくにつれて短くなるように第２面２２が第１面２１に対し傾斜角θで傾斜するからである。すなわち、第３入射角α１は、図４に示す第１入射角αよりも小さい角であることにより、第２屈折角β１が屈折角βよりも小さくなる。この大小関係により、第４入射角γ１が第２入射角γよりも小さくなる。この結果、ＨＭＤ１の正面方向からの外光が第１面２１において全反射しない。また、ハーフミラー２０は、特許文献１に開示された偏向フィルタ、およびルーバーなどの外光を遮る構成を備えない。すなわち、外光がユーザの眼に入射することにより視認される外界の明るさは、低減しない。 External light transmitted through the inside of the half mirror 20 is not totally reflected at the first surface 21. On the second surface 22, (Equation 3-2) is shown by the fourth incident angle γ 1 and the refractive index n of the polycarbonate forming the half mirror.

As shown in FIG. 4, the second length is such that the length in the direction of the normal line NL1 of the first surface 21 between the first surface 21 and the second surface 22 becomes shorter as the generation unit 10 is approached. This is because the surface 22 is inclined with respect to the first surface 21 at an inclination angle θ. That is, the third incident angle α1 is smaller than the first incident angle α shown in FIG. 4, so that the second refraction angle β1 is smaller than the refraction angle β. Due to this magnitude relationship, the fourth incident angle γ1 becomes smaller than the second incident angle γ. As a result, external light from the front direction of the HMD 1 is not totally reflected at the first surface 21. Further, the half mirror 20 does not have a configuration that blocks outside light such as a deflection filter and a louver disclosed in Patent Document 1. That is, the brightness of the external environment visually recognized when external light enters the user's eyes is not reduced.

[effect]
According to the present embodiment, the second incident angle γ of the transmitted light on the second surface 22 is equal to or greater than the critical angle. As a result, the transmitted light transmitted through the first surface 21 is totally reflected at the second surface 22. On the second surface 22, the traveling direction of the totally reflected transmitted light is directed to the user side with respect to the traveling direction of the image light generated by the generation unit 10. Thereby, the transmitted light totally reflected on the second surface 22 is reduced from entering the eyes ES of other users positioned in the traveling direction of the image light generated by the generation unit 10. Further, unlike the technique disclosed in Patent Document 1, the HMD 1 of the present invention does not include the display unit side louver optical element in the generation unit 10. As a result, limiting the viewing angle of the generator is reduced. Therefore, it is reduced that the user wearing the HMD 1 cannot clearly recognize the image formed by the reflected light from the first surface 21 of the half mirror 20. On the other hand, external light incident from the second surface 22 side can be totally reflected on the first surface 21 by the second surface 22 in which the second incident angle γ of the transmitted light transmitted through the first surface 21 is greater than or equal to the critical angle. Low. Further, the half mirror 20 does not have a configuration such as a louver or a polarizing filter that blocks the image light generated by the generation unit 10 and external light incident from the second surface 22 side. As a result, it is reduced that external light does not enter the eyes of the user wearing the HMD 1. Therefore, in the traveling direction of the image light generated by the generation unit 10, it is possible to reduce the external light and the dimming of the image light forming the image while reducing the risk of the image leaking to other users.

  According to the present embodiment, the second surface 22 totally reflects the transmitted light. On the second surface 22, the totally reflected reflected light travels toward the user wearing the HMD 1. As a result, a part of the transmitted light transmitted through the first surface 21 is totally reflected on the second surface 22 and forms an image on the face of the user wearing the HMD 1. Accordingly, a part of the transmitted light that has passed through the first surface 21 forms an image, thereby reducing the risk of leakage of the image to other users while reducing the external light and the image light that forms the image. It can be suppressed.

  According to the present embodiment, the second surface 22 is inclined with respect to the first surface 21 at an inclination angle θ that is not less than the lower limit angle θm and less than 90 °. As a result, the light transmitted through the first surface 21 at the first incident angle α is totally reflected at the second surface 22. On the second surface 22, the totally reflected reflected light travels toward the user wearing the HMD 1. As a result, a part of the transmitted light transmitted through the first surface 21 is totally reflected on the second surface 22 and forms an image on the face of the user wearing the HMD 1. Therefore, by forming an image in a region where the user's face is located with a part of the transmitted light that has passed through the first surface 21, the external light and the image are reduced while reducing the risk of the image leaking to other users. Dimming of image light to be formed can be suppressed.

  According to this embodiment, the 2nd surface 22 is arrange | positioned so that the reflected light totally reflected in the 2nd surface 22 may face between a user's both eyes. Specifically, the tilt angle θ is smaller than the tilt angle θc when the totally reflected image light is incident on the right eye RE of the user wearing the HMD 1. As a result, part of the transmitted light that has passed through the first surface 21 is totally reflected on the second surface 22, and the formation of an image on the right eye RE that is the other eye can be suppressed. Accordingly, since the user does not form an image on the right eye RE that is the other eye, the user can easily visually recognize the outside world with the left eye LE that is the one eye.

[Modification 1]
In the present embodiment, as shown in FIG. 7, the third surface 23 that intersects the first surface 21 and the second surface 22 is formed on the half mirror 20, but the third surface 23 is formed on the half mirror 20. It is not necessary. That is, the first surface 21 and the second surface 22 may intersect. When the first surface 21 and the second surface 22 intersect, the thickness of the half mirror 20 becomes thin. When the thickness of the half mirror 20 is reduced, the optical path of outside light inside the half mirror 20 is shortened. When the optical path of the external light inside the half mirror 20 is shortened, the external image formed by the external light transmitted through the half mirror 20 entering the user's eyes may be shifted from the actual external image position. Reduced. As a result, the user wearing the HMD 1 recognizes the outside world close to the actual outside world. Therefore, when the second surface 22 intersects with the first surface 21, the user can recognize the outside world in which the positional deviation is suppressed as compared with the half mirror 20 in which the second surface 22 does not intersect with the first surface 21.

[Modification 2]
In the present embodiment, as shown in FIG. 4, the reflected light totally reflected on the second surface 22 travels in the direction of the user wearing the HMD 1. Not limited to this, even if the second incident angle γ on the second surface 22 is smaller than the critical angle, the refracted light refracted on the second surface 22 is directed toward the user wearing the HMD 1, that is, the user's It suffices to proceed to the area where the face is located and the area around the area where the face is located, where other users cannot approach. That is, the second incident angle γ of the transmitted light transmitted through the first surface 21 may be in the vicinity of the critical angle.

[Modification 3]
In the present embodiment, the first surface 21 and the second surface of the half mirror 20 are flat surfaces, but may be curved surfaces. Moreover, in above-described embodiment, the head mounting part 2 was demonstrated as an example of a flame | frame. However, other mounting portions may be used as the frame. For example, the HMD 1 may be a mounting unit that mounts the generating unit 10 on the head using a headband like goggles. Or the mounting part attached with respect to a user's ear | edge may be sufficient. In addition, when the generation unit 10 can be attached to the eyesight correction glasses used by the user, the eyesight correction glasses themselves become the mounting portion.

DESCRIPTION OF SYMBOLS 1 Head mounted display 2 Head mounting part 10 Generating part 11 LCD
12 Lens system 20 Half mirror 21 First surface 22 Second surface

Claims (3)

A head-mounted display that is attached to a frame that is mounted on the user's head and that recognizes an image by the user by image light based on image information being incident on the user's eyes,
A generator for generating image light in which the image is a virtual image;
A half mirror disposed in the user's field of view;
With
The half mirror is
A first surface that reflects a part of the image light generated by the generation unit in the direction of the eyes of the user;
A second surface that is inclined at a predetermined angle with respect to the first surface, and an incident angle of transmitted light that is the other part of the image light transmitted through the first surface is close to a critical angle;
With
The second surface is inclined at a predetermined angle with respect to the first surface so as to totally reflect the transmitted light,
The material of the half mirror has a refractive index n,
The first surface is disposed at a position where the image light has an incident angle α,
The second surface is inclined at an inclination angle θ with respect to the first surface,
The inclination angle θ is

A head-mounted display having a lower limit angle θm satisfying the above condition and less than 90 degrees. A head-mounted display that is attached to a frame that is mounted on the user's head and that recognizes an image by the user by image light based on image information being incident on the user's eyes,
A generator for generating image light in which the image is a virtual image;
A half mirror disposed in the user's field of view;
With
The half mirror is
A first surface that reflects a part of the image light generated by the generation unit in the direction of the eyes of the user;
A second surface that is inclined at a predetermined angle with respect to the first surface, and an incident angle of transmitted light that is the other part of the image light transmitted through the first surface is close to a critical angle;
With
The second surface is inclined at a predetermined angle with respect to the first surface so as to totally reflect the transmitted light,
The half mirror is arranged in the visual field of one eye of the user,
The head-mounted display, wherein the second surface is arranged so that the reflected light totally reflected on the second surface is directed between the eyes of the user. A head-mounted display that is attached to a frame that is mounted on the user's head and that recognizes an image by the user by image light based on image information being incident on the user's eyes,
A generator for generating image light in which the image is a virtual image;
A half mirror disposed in the user's field of view;
With
The half mirror is
A first surface that reflects a part of the image light generated by the generation unit in the direction of the eyes of the user;
A second surface that is inclined at a predetermined angle with respect to the first surface, and an incident angle of transmitted light that is the other part of the image light transmitted through the first surface is close to a critical angle;
With
The head-mounted display, wherein the second surface intersects the first surface on the generation unit side.

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