JP2015127828A - Virtual image display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device in which luminance spot is suppressed.SOLUTION: A filter 50 is arranged between a projection optical system 12 and a light guide device 20, and changes a spatial distribution of a transmitted light volume. Consequently, an image with suppressed luminance spot is displayed to an observer, even when the image as the virtual image formed by the projection optical system and a light guide device 20 has a comparatively large luminance spot. Thus, the virtual image displayed by a virtual image display device 100 is made high quality while enlarging the size of the displayed image.

Description

  The present invention relates to a virtual image display device such as a head mounted display that is used by being mounted on a head.

  2. Description of the Related Art In recent years, various types of virtual image display devices capable of forming and observing virtual images such as a head-mounted display have been proposed that guide image light from a display element to an observer's pupil using a light guide plate.

  In such a virtual image display device, a see-through optical system has been proposed to superimpose image light and external light (see Patent Documents 1 and 2).

  However, in the apparatus described in Patent Document 1 and the like, see-through is realized by a pupil division method using a light guide optical system smaller than the pupil size, so it is difficult to increase the display size of the virtual image. In addition, since a light guide optical system smaller than the pupil size is used, an effective pupil diameter (a light-collecting diameter that enables capturing of a virtual image, also referred to as an eye ring diameter) is increased in order to cope with human individual eye widths. Difficult to do. In addition, since the exit opening and the housing of the light guide optical system are physically disposed near the pupil, a blind spot is generated and it cannot be said that the see-through is complete.

  There is an optical system for a head-mounted display that includes a light guide pipe that can advance a plurality of light modes having different light guide angles (see Patent Document 3). In such an optical system, it is conceivable to make a see-through display device by devising such that the third optical surface on the emission side is a half mirror and the transmitted light of the third optical surface goes straight.

  However, in the optical system of Patent Document 3, the liquid crystal panel is illuminated with collimated light set at different incident angles for each light mode on the premise that images in a plurality of light modes are displaced from each other. Then, the display contents are changed in each light mode and the display in each light mode is executed sequentially, so that images in the respective light modes are connected to obtain an entire image. In this case, the central image and the left and right images constituting the entire image must be displayed while being changed with a time difference by one liquid crystal panel, which complicates the virtual image display device and darkens the observation image.

  Apart from the above, a virtual image display device that enables observation of a virtual image superimposed on external light by a light guide member having a light emitting part that covers the front of the eye, which does not need to join images with a time difference However, it is not easy to display a large image, and luminance spots are easily generated in the image.

JP 2006-3879 A JP 2010-224473 A JP 2008-535001 A

  The present invention has been made in view of the above problems of the background art, and an object thereof is to provide a virtual image display device in which luminance spots are suppressed.

  In order to solve the above problems, a virtual image display device according to the present invention includes (a) an image display device that forms image light, (b) a projection optical system that makes the image light emitted from the image display device enter, c) a light guide unit, a light incident unit that causes the image light to enter the light guide unit, and a light emission unit that emits the image light guided by the light guide unit to the outside. And (d) the light guide unit includes a first reflection surface and a second reflection surface that are arranged in parallel to each other and enable light guide by total reflection. (E) The light incident part has a third reflection surface that forms a predetermined angle with respect to the first reflection surface, and (f) the light emission part has a predetermined value with respect to the first reflection surface. Having a fourth reflecting surface forming an angle, and (g) having a light transmitting surface bonded to the fourth reflecting surface of the light emitting part via the reflecting surface, A light transmitting member that constitutes a see-through unit by being combined with the light guiding device, and (h) a filter that is disposed between the projection optical system and the light guiding device and changes a spatial distribution of the passing light amount. Prepare.

  In the virtual image display device, the image light reflected by the third reflecting surface of the light incident portion is propagated while being totally reflected by the first and second reflecting surfaces of the light guide portion, and is reflected by the fourth reflecting surface of the light emitting portion. And enters the observer's eyes as a virtual image. In this case, the effective pupil diameter can be increased, and the displayed virtual image can be made large in size with high quality. Further, by combining the light guide device and the light transmitting member, see-through observation is possible through the fluoroscopic part, and a virtual image can be superimposed on the external image and observed. Furthermore, in the virtual image display device, the filter is disposed between the projection optical system and the light guide device, and changes the spatial distribution of the amount of light passing through, so as a virtual image formed by the projection optical system and the light guide device. Even if the image has a relatively large luminance spot, an image in which the luminance spot is suppressed can be displayed to the observer.

  In a specific aspect of the present invention, in the virtual image display device, the filter is an ND filter that attenuates light by absorption. In this case, luminance spots can be directly compensated by the absorption rate pattern.

  In another aspect of the present invention, the filter is a filter in which a metal reflective film is formed on a light-transmitting substrate. In this case, the luminance unevenness can be compensated by the reflectance pattern.

  In still another aspect of the present invention, the filter is a micro-pattern type filter in which a transmission part and a light-shielding part are formed in a predetermined pattern. In this case, adjustment of the absorption rate of the absorption film itself and the reflection rate of the reflection film itself becomes unnecessary, and the adjustment of the transmittance in each region where the transmission part and the light shielding part are combined becomes simple and precise.

  In still another aspect of the present invention, the transmission parts of the filter forming the predetermined pattern each have a size of 0.2 mm or more. In this case, diffraction by the fine pattern type filter can be suppressed.

  In still another aspect of the present invention, the filter is provided between the projection optical system and the light incident surface of the light incident portion. In this case, it is easy to secure space and protect the filter.

  In still another aspect of the present invention, the light guide device is a block-shaped member in which the light guide unit, the light incident unit, and the light emitting unit are integrated, and the filter guides the light incident surface of the light guide device. It is adhered to the light incident surface through a light transmission layer having a refractive index lower than that of the device by a predetermined value or more. In this case, it is easy to fix the filter, and it is easy to ensure total reflection at the light guide section.

  In still another aspect of the present invention, the filter is formed on the surface of a lens constituting the projection optical system.

  In still another aspect of the present invention, the filter is disposed on the light exit surface of the light exit section. In this case, luminance unevenness can be compensated by a pattern that directly corresponds to the distribution of transmitted light amount.

  In still another aspect of the present invention, a filter is provided along with at least one of the second reflecting surface and the third reflecting surface. In this case, at the time of reflection on the second reflection surface or the third reflection surface, the transmittance or the distribution of the reflectance is adjusted, and the luminance unevenness can be compensated.

  In yet another aspect of the present invention, the filter has a transmittance distribution that varies depending on the position. In this case, compensation for the optical path difference is also possible.

  In still another aspect of the present invention, the first portion regarding the number of reflections of the first image light emitted from the first partial region in the image display device in the light guide and the confinement direction in which the optical path is turned back by the reflection during the light guide. The number of reflections of the second image light emitted from the second partial region different from the region is different from each other. In this case, by using image light having a different number of reflections, it is possible to increase the angle width of the emission angle of the image light emitted from the light emitting unit. That is, image light from different display areas in the image display device can be captured with a relatively wide viewing angle, and a large display size of a virtual image observed through the light emitting unit can be secured. By adopting a structure for extracting image light with different number of reflections in this way, the light emission part can be enlarged so as to cover the pupil without making the light guide part too thick, so that good see-through observation is possible. .

  In still another aspect of the invention, the confinement direction is a direction parallel to a cross section including the first optical axis passing through the projection optical system and the normal line of the third reflecting surface. The image light from different positions with respect to the confinement direction can be made to have a different number of reflections in the light guide portion by making the emission angle, that is, the incident angle to the light incident portion, different from each other.

  In still another aspect of the present invention, the light guide device is molded by injection molding, and the light guide device is molded by a heat polymerization type resin material.

It is a perspective view which shows the virtual image display apparatus of 1st Embodiment. (A) is a top view of the main-body part of the 1st display apparatus which comprises a virtual image display apparatus, (B) is a front view of a main-body part. (A) is a figure explaining the structure of the 3rd reflective surface in the light-incidence part of a light guide member, (B) is a figure explaining the structure of the 1st reflective surface in the light guide part of a light guide member. (C) is a figure explaining the structure of the 2nd reflective surface in the light guide part of a light guide member, (D) demonstrates the structure of the 4th reflective surface in the light emission part of a light guide member. FIG. (A) is the conceptual diagram which expand | deployed the optical path regarding the vertical 1st direction, (B) is the conceptual diagram which expand | deployed the optical path regarding the horizontal 2nd direction. It is a top view explaining the optical path in the optical system of a virtual image display apparatus concretely. (A) shows the display surface of a liquid crystal display device, (B) is a figure explaining notionally the virtual image of the liquid crystal display device which an observer can see, (C) and (D) comprise a virtual image It is a figure explaining the partial image to do. (A) is a chart explaining the light distribution pattern of the image light inject | emitted from an image display apparatus, (B) is a notional enlarged view explaining the pixel structure of a liquid crystal display device. (A) is a front view of a filter, (B) is a figure which illustrates the absorptivity pattern of a filter notionally. (A) shows the luminance distribution of the image seen by the observer in the specific example, (B) is a graph of the luminance distribution, and (C) shows the luminance distribution of the image seen by the observer in the comparative example. (D) is a graph showing the luminance distribution. It is a figure explaining the reason which has provided the end surface which removes a ridge in a light guide member. (A) is a figure explaining the light guide state of the image light in a modification, (B) is a figure explaining notionally the virtual image of the liquid crystal display device in a modification. It is a top view of the principal part which comprises the virtual image display apparatus of 2nd Embodiment. (A) is a perspective view of a filter, (B) is an expanded section of a filter. (A) And (B) is a figure explaining the fine pattern of a metal reflective film. It is a top view of the principal part which comprises the virtual image display apparatus of 3rd Embodiment. It is a figure explaining the low transmittance | permeability distribution of a filter. It is a top view of the principal part which comprises the virtual image display apparatus of 4th Embodiment. (A) is a top view of the principal part which comprises the virtual image display apparatus of 5th Embodiment, (B) is a conceptual diagram explaining the cross-sectional structure of a filter periphery. (A) is a top view of the principal part which comprises the virtual image display apparatus of 6th Embodiment, (B) is a conceptual diagram explaining the cross-sectional structure of a filter periphery. It is a figure which illustrates notionally the image of the liquid crystal display device in a modification.

[First Embodiment]
Hereinafter, a virtual image display device according to a first embodiment of the present invention will be described in detail with reference to the drawings.

[A. Appearance of virtual image display device)
The virtual image display device 100 according to the first embodiment shown in FIG. 1 is a head-mounted display having an appearance like glasses, and allows an observer wearing the virtual image display device 100 to recognize image light due to a virtual image. In addition, it is possible to make the observer observe the outside world image with see-through. The virtual image display device 100 includes an optical panel 110 that covers the viewer's eyes, a frame 121 that supports the optical panel 110, and first and second drive units 131 and 132 that are added to a portion of the frame 121 from the end to the temple. With. Here, the optical panel 110 has a first panel portion 111 and a second panel portion 112, and both the panel portions 111 and 112 are plate-like parts integrally connected at the center. The first display device 100A in which the first panel portion 111 on the left side and the first drive unit 131 are combined in the drawing is a portion that forms a virtual image for the left eye, and functions alone as a virtual image display device. Further, the second display device 100B in which the second panel portion 112 on the right side and the second driving unit 132 in the drawing are combined is a portion that forms a virtual image for the right eye, and functions alone as a virtual image display device.

[B. (Structure of display device on one side)
As shown in FIG. 2A and the like, the first display device 100A includes an image forming device 10, a light guide device 20, and a filter 50. Here, the image forming apparatus 10 corresponds to the first driving unit 131 in FIG. 1, and the light guide device 20 corresponds to the first panel portion 111 in FIG. Note that the second display device 100B shown in FIG. 1 has the same structure as the first display device 100A and is simply flipped left and right, and thus detailed description of the second display device 100B is omitted.

  The image forming apparatus 10 includes an image display device 11 and a projection optical system 12. Among these, the image display device 11 operates the illumination device 31 that emits the two-dimensional illumination light SL, the liquid crystal display device 32 that is a transmissive spatial light modulation device, and the operations of the illumination device 31 and the liquid crystal display device 32. And a drive control unit 34 for controlling.

  The illuminating device 31 includes a light source 31a that generates light including three colors of red, green, and blue, and a backlight light guide unit 31b that diffuses light from the light source 31a into a light beam having a rectangular cross section. The liquid crystal display device 32 spatially modulates the illumination light SL from the illumination device 31 to form image light to be a display target such as a moving image. The drive control unit 34 includes a light source drive circuit 34a and a liquid crystal drive circuit 34b. The light source driving circuit 34a supplies electric power to the light source 31a of the lighting device 31 to emit the illumination light SL having a stable luminance. The liquid crystal driving circuit 34b outputs an image signal or a driving signal to the liquid crystal display device 32, thereby forming color image light that is a source of a moving image or a still image as a transmittance pattern. The liquid crystal driving circuit 34b can have an image processing function, but an external control circuit can also have an image processing function. The projection optical system 12 is a collimating lens that converts image light emitted from each point on the liquid crystal display device 32 into light beams in a parallel state.

In the liquid crystal display device 32, the first direction D1 is a direction in which a longitudinal section including a first optical axis AX1 passing through the projection optical system 12 and a specific line parallel to a third reflecting surface 21c of the light guide member 21 described later extends. The second direction D2 corresponds to a direction in which a transverse section including the first optical axis AX1 and the normal line of the third reflecting surface 21c extends. In other words, the first direction D1 is a direction parallel to an intersection line CL between a first reflecting surface 21a and a third reflecting surface 21c of the light guide member 21 described later, and the second direction D2 is the first reflecting surface. The direction is parallel to the plane of 21a and perpendicular to the line of intersection CL between the first reflecting surface 21a and the third reflecting surface 21c.
Note that the effective size of the liquid crystal display device 32 is longer in the second direction D2 than in the first direction D1. On the other hand, the exit aperture width of the projection optical system 12 is longer in the first direction D1 than in the second direction D2.

  The light guide device 20 is formed by joining a light guide member 21 and a light transmission member 23, and constitutes a flat plate-like optical member that extends parallel to the XY plane as a whole.

  In the light guide device 20, the light guide member 21 is a trapezoidal prism-like member in plan view, and includes, as side surfaces, a first reflection surface 21 a, a second reflection surface 21 b, a third reflection surface 21 c, and a fourth reflection surface. A reflective surface 21d. The light guide member 21 includes an upper surface 21e and a lower surface 21f that are adjacent to the first, second, third, and fourth reflecting surfaces 21a, 21b, 21c, and 21d and that face each other. Here, the first and second reflecting surfaces 21 a and 21 b extend along the XY plane and are separated by the thickness t of the light guide member 21. The third reflecting surface 21c is inclined at an acute angle α of 45 ° or less with respect to the XY plane, and the fourth reflecting surface 21d is inclined at an acute angle β of 45 ° or less with respect to the XY surface, for example. . The first optical axis AX1 passing through the third reflecting surface 21c and the second optical axis AX2 passing through the fourth reflecting surface 21d are arranged in parallel and separated by a distance D. As will be described in detail below, an end surface 21h is provided between the first reflecting surface 21a and the third reflecting surface 21c so as to remove a ridge. The light guide member 21 has a polyhedral outer shape with seven surfaces including the end surface 21h.

  The light guide member 21 performs light guide using total reflection by the first and second reflection surfaces 21a and 21b, and is a direction that is folded by reflection when light is guided and a direction that is not folded by reflection when light is guided. There is. When an image guided by the light guide member 21 is considered, the lateral direction that is turned back by a plurality of reflections during light guide, that is, the confinement direction, is perpendicular to the first and second reflecting surfaces 21a and 21b (parallel to the Z axis) Thus, when the optical path is expanded to the light source side as will be described later, it corresponds to the second direction D2 of the liquid crystal display device 32, and the longitudinal direction that is not turned back by reflection during light guide, that is, the free propagation direction is When the optical path is expanded to the light source side as will be described later in parallel to the second reflecting surfaces 21a and 21b and the third reflecting surface 21c (parallel to the Y axis), it corresponds to the first direction D1 of the liquid crystal display device 32.

  The light guide member 21 is formed of a resin material that exhibits high light transmittance in the visible range. The light guide member 21 is a block-like member integrally molded by injection molding, and is formed by, for example, injecting a thermopolymerization resin material into a molding die and thermosetting it. Thus, although the light guide member 21 is an integrally formed product, it can be functionally divided into the light incident part B1, the light guide part B2, and the light emitting part B3.

  The light incident part B1 is a triangular prism-shaped part, and includes a light incident surface IS that is a part of the first reflective surface 21a and a third reflective surface 21c that faces the light incident surface IS. The light incident surface IS is a flat surface on the back side or the viewer side for taking in the image light GL from the image forming apparatus 10 and extends perpendicularly to the first optical axis AX1 facing the projection optical system 12. The third reflecting surface 21c is a rectangular total reflection mirror for reflecting the image light GL that has passed through the light incident surface IS and guiding it into the light guide B2.

  FIG. 3A is a diagram illustrating the third reflecting surface 21c, and is a partial enlarged cross-sectional view of the surface portion P1 in the light incident portion B1. The third reflecting surface 21 c has a mirror layer 25 and is covered with a protective layer 26. The mirror layer 25 is a total reflection coating, and is formed by depositing aluminum on the inclined surface RS of the light guide member 21 by vapor deposition. The third reflecting surface 21c is inclined with respect to the first optical axis AX1 or the XY plane of the projection optical system 12, for example, at an acute angle α = 25 ° to 27 °, and is incident from the light incident surface IS in the + Z direction as a whole. The image light GL that is directed is bent so as to be directed in the −X direction that is closer to the −Z direction as a whole, so that the image light GL is reliably coupled into the light guide portion B2.

  Referring back to FIG. 2A and the like, the light guide B2 is formed as two planes facing each other and extending in parallel to the XY plane, and a first reflecting surface 21a that totally reflects the image light bent at the light incident portion B1. And a second reflecting surface 21b. The distance between the first and second reflecting surfaces 21a and 21b, that is, the thickness t of the light guide member 21 is, for example, about 9 mm. Here, it is assumed that the first reflecting surface 21a is on the back side or the viewer side close to the image forming apparatus 10, and the second reflecting surface 21b is on the front side or the outside side far from the image forming apparatus 10. In this case, the first reflecting surface 21a is a surface portion common to the above-described light incident surface IS and a light emitting surface OS described later. The first and second reflection surfaces 21a and 21b are total reflection surfaces using a difference in refractive index, and are not provided with a reflection coating such as a mirror layer.

  FIG. 3B is a diagram illustrating the first reflecting surface 21 a and is a partial enlarged cross-sectional view of the surface portion P <b> 1 in the light guide portion B <b> 2 of the light guide member 21. FIG. 3C is a diagram for explaining the first reflecting surface 21 a and is a partial enlarged cross-sectional view of the surface portion P <b> 1 in the light guide portion B <b> 2 of the light guide member 21. However, the first and second reflecting surfaces 21a and 21b are covered with a hard coat layer 27 in order to prevent the surface from being damaged and the resolution of the image from being lowered. The hard coat layer 27 is formed by depositing a UV curable resin, a thermosetting resin, or the like on the flat surface FS of the light guide member 21 by dipping or spray coating. The image light GL reflected by the third reflecting surface 21c of the light incident part B1 first enters the first reflecting surface 21a and is totally reflected. Next, the image light GL enters the second reflecting surface 21b and is totally reflected. Thereafter, by repeating this operation, the image light is guided to the back side of the light guide device 20, that is, the -X side provided with the light emitting part B3. In addition, since the 1st and 2nd reflective surfaces 21a and 21b are not provided with the reflective coating, the external light or the external light incident on the second reflective surface 21b from the external side passes through the light guide B2 with high transmittance. pass. In other words, the light guide B2 is a see-through type that allows the external image to be seen through.

  The total reflection on the first and second reflecting surfaces 21a and 21b described above depends on the setting of the refractive index of the hard coat layer 27 and can be generated inside the surface SS of the hard coat layer 27, but the flat surface FS. It can also occur inside.

  Returning to FIG. 2A and the like, the light emission part B3 is a triangular prism-like part, and a light emission surface OS that is a part of the first reflection surface 21a and a fourth reflection that faces the light emission surface OS. 21d. The light exit surface OS is a flat surface on the back side for emitting the image light GL toward the observer's eye EY. The light exit surface OS is a part of the first reflecting surface 21a like the light incident surface IS. It extends perpendicular to the optical axis AX2. The distance D between the second optical axis AX2 passing through the light emitting part B3 and the first optical axis AX1 passing through the light incident part B1 is set to, for example, 50 mm in consideration of the width of the observer's head. The fourth reflecting surface 21d is a rectangular flat surface for reflecting the image light GL incident through the first and second reflecting surfaces 21a and 21b and emitting it outside the light emitting portion B3. have. The half mirror layer 28 is a light-transmissive reflective film (that is, a semi-transmissive reflective film), and the surface thereof is a semi-transmissive reflective surface.

  FIG. 3D is a diagram illustrating the fourth reflecting surface 21d, and is a partial enlarged cross-sectional view of the surface portion P4 in the light emitting portion B3. The fourth reflecting surface 21d is accompanied by a half mirror layer (light-transmitting reflecting film or semi-transmitting reflecting film) 28. The half mirror layer 28 is formed of a metal reflecting film or the like on the slope RS of the light guide member 21. It is formed by forming a dielectric multilayer film. The reflectance of the half mirror layer 28 with respect to the image light GL is set to 10% to 50% in the assumed incident angle range of the image light GL from the viewpoint of facilitating observation of the external light GL ′ by see-through. The reflectance of the half mirror layer 28 of the specific embodiment with respect to the image light GL is set to 20%, for example, and the transmittance with respect to the image light GL is set to 80%, for example.

  The fourth reflecting surface 21d is inclined with respect to the second optical axis AX2 or XY plane perpendicular to the first reflecting surface 21a, for example, at an acute angle α = 25 ° to 27 °, and is guided by the half mirror layer 28. The image light GL incident through the first and second reflecting surfaces 21a and 21b of the portion B2 is partially reflected and bent so as to be directed in the −Z direction as a whole, thereby allowing the light exit surface OS to pass therethrough. Note that the image light GL transmitted through the fourth reflecting surface 21d is incident on the light transmitting member 23 and is not used to form an image.

  The light transmission member 23 has the same refractive index as that of the main body of the light guide member 21, and includes a first surface 23a, a second surface 23b, and a third surface 23c. The first and second surfaces 23a and 23b extend along the XY plane. The third surface 23 c is inclined with respect to the XY plane, and is disposed in parallel to face the fourth reflecting surface 21 d of the light guide member 21. That is, the light transmission member 23 is a member having a wedge-shaped portion sandwiched between the second surface 23b and the third surface 23c. Similar to the light guide member 21, the light transmissive member 23 is formed of a resin material exhibiting high light transmittance in the visible region. The light transmitting member 23 is a block-like member that is integrally molded by injection molding, and is formed, for example, by injecting a thermopolymerization resin material into a molding die and thermosetting it.

  In the light transmission member 23, the first surface 23 a is disposed on the extended plane of the first reflecting surface 21 a provided on the light guide member 21, is on the back side close to the observer's eye EY, and the second surface 23 b is guided. It is arranged on the extended plane of the second reflecting surface 21b provided on the optical member 21, and is on the front side far from the observer's eye EY. The third surface 23c is a rectangular transmission surface joined to the fourth reflection surface 21d of the light guide member 21 by an adhesive. The angle formed by the first surface 23a and the third surface 23c is equal to the angle ε formed by the second reflective surface 21b and the fourth reflective surface 21d of the light guide member 21, and the second surface 23b and the third surface 23c are the same. The angle formed with the surface 23 c is equal to the angle β formed between the first reflecting surface 21 a and the third reflecting surface 21 c of the light guide member 21.

  The light transmitting member 23 and the light guide member 21 constitute a see-through portion B4 in front of the eyes EY of the observer at the joint portion between them and in the vicinity thereof. Of the light transmitting member 23, a wedge-shaped member 23m that is sandwiched between the second surface 23b and the third surface 23c that form an acute angle and expands in the −X direction is similarly joined to the wedge-shaped light emitting portion B3. The central portion in the X direction of the flat see-through portion B4 as a whole is configured. Since the first and second surfaces 23a and 23b are not provided with a reflective coating such as a mirror layer, the external light GL ′ is transmitted with a high transmittance similarly to the light guide portion B2 of the light guide member 21. The third surface 23c can also transmit the external light GL ′ with high transmittance, but since the fourth reflecting surface 21d of the light guide member 21 has the half mirror layer 28, the third surface 23c passes through the third surface 23c. The ambient light GL ′ to be reduced is reduced by 20%, for example. That is, the observer observes the image light GL that has been reduced to 20% and the external light GL ′ that has been reduced to 80%.

  The filter 50 is disposed so as to be inserted into a gap portion between the projection optical system 12 and the light guide member 21. The filter 50 is a sheet-like member, and is fixed in the case of the first drive unit 131 shown in FIG. 1 and extends parallel to the XY plane. The filter 50 is, for example, an ND filter, and has a role of changing the spatial distribution of the transmitted light amount.

[C. Overview of optical path of image light)
4A is a diagram illustrating an optical path in the first direction D1 corresponding to the longitudinal section CS1 of the liquid crystal display device 32. FIG. In the longitudinal section along the first direction D1, that is, the YZ plane (the unfolded Y′Z ′ plane), among the image light emitted from the liquid crystal display device 32, the upper end side of the display area 32b indicated by the alternate long and short dash line in FIG. The component emitted from the (+ Y side) is referred to as image light GLa, and the component emitted from the lower end side (−Y side) of the display area 32b indicated by the two-dot chain line in the drawing is referred to as image light GLb.

The upper image light GLa is converted into a parallel light flux by the projection optical system 12 and passes through the light incident part B1, the light guide part B2, and the light emission part B3 of the light guide member 21 along the developed optical axis AX ′. The incident light is inclined with respect to the eye EY of the observer in a parallel light flux state from above the angle φ ₁ . On the other hand, the lower image light GLb is converted into a parallel light flux by the projection optical system 12, and along the developed optical axis AX ′, the light incident part B <b> 1, the light guide part B <b> 2, and the light emission part of the light guide member 21. The light passes through B3 and is incident on the observer's eye EY in a state of a parallel light beam, tilted from below the angle φ ₂ (| φ ₂ | = | φ ₁ |). The above angles φ ₁ and φ ₂ correspond to the upper and lower half angles of view, and are set to, for example, 6.5 °.

  FIG. 4B is a diagram illustrating an optical path in the second direction (confinement direction or synthesis direction) D2 corresponding to the cross section CS2 of the liquid crystal display device 32. In the cross section along the second direction (confinement direction or synthesis direction) D2, that is, the XZ plane (X′Z ′ plane after development), the image light emitted from the liquid crystal display device 32 is indicated by a one-dot chain line in the figure. The component emitted from the first display point P1 on the right end side (+ X side) toward the display area 32b is the image light GLc, and the component on the left end side (−X side) toward the display area 32b indicated by the two-dot difference line in the figure. A component emitted from the second display point P2 is defined as image light GLd. In FIG. 6B, image light GLe emitted from the inner right side and image light GLf emitted from the inner left side are added for reference.

The image light GLc from the first display point P1 on the right side is converted into a parallel light beam by the projection optical system 12, and along the developed optical axis AX ′, the light incident part B1, the light guide part B2, Then, it passes through the light emitting part B3 and is incident on the observer's eye EY in a state of a parallel light beam inclined from the left direction of the angle θ ₁ . On the other hand, the image light GLd from the second display point P2 on the left side is converted into a parallel light beam by the projection optical system 12, and along the developed optical axis AX ′, the light incident part B1 and the light guide part of the light guide member 21. The light passes through B2 and the light emission part B3, and enters the observer's eye EY in a state of a parallel light beam, tilted from the right direction at an angle θ ₂ (| θ ₂ | = | θ ₁ |). The above angles θ ₁ and θ ₂ correspond to the left and right half angles of view, and are set to 10 °, for example.

Note that, in the horizontal direction of the second direction D2, the image lights GLc and GLd are folded back by reflection in the light guide member 21 and the number of reflections is different, so that each image light GLc and GLd is in the light guide member 21. It is expressed discontinuously. In addition, regarding the observer's eye EY, the viewing direction is upside down compared to the case of FIG. As a result, the screen is horizontally reversed as a whole in the horizontal direction, but the right half image of the liquid crystal display device 32 and the liquid crystal display device can be obtained by processing the light guide member 21 with high accuracy as will be described in detail later. The images on the left half of 32 are continuously joined without any gap. In consideration of the fact that the number of reflections of the two image lights GLc and GLd in the light guide member 21 is different from each other, the emission angle θ ₁ ′ of the right image light GLc and the emission angle θ ₂ ′ of the left image light GLd. Is set to something different.

  As described above, the image lights GLa, GLb, GLc, and GLd incident on the observer's eye EY are virtual images from infinity, and the image formed on the liquid crystal display device 32 is correct in the first vertical direction D1. The image formed on the liquid crystal display device 32 is reversed with respect to the second horizontal direction D2.

[D. (The optical path of image light in the horizontal direction)
FIG. 5 is a cross-sectional view illustrating a specific optical path in the first display device 100A. The projection optical system 12 has three lenses L1, L2, and L3.

The image lights GL11 and GL12 from the first display point P1 on the right side of the liquid crystal display device 32 pass through the lenses L1, L2 and L3 of the projection optical system 12 to be converted into parallel light beams, and the light incident surface of the light guide member 21 Incident on IS. The image lights GL11 and GL12 guided into the light guide member 21 repeat total reflection at the same angle on the first and second reflection surfaces 21a and 21b, and are finally emitted as a parallel light flux from the light exit surface OS. . Specifically, the image lights GL11 and GL12 are reflected by the third reflection surface 21c of the light guide member 21 as parallel light beams, and then enter the first reflection surface 21a of the light guide member 21 at the first reflection angle γ1. , Total reflection (first total reflection). Thereafter, the image lights GL11 and GL12 are incident on the second reflecting surface 21b and totally reflected (second total reflection) while maintaining the first reflection angle γ1, and then incident on the first reflecting surface 21a again. And is totally reflected (third total reflection). As a result, the image lights GL11 and GL12 repeat total reflection on the first and second reflection surfaces 21a and 21b while maintaining the first reflection angle γ1. The image lights GL11 and GL12 are totally reflected a total of three times on the first and second reflecting surfaces 21a and 21b, and enter the fourth reflecting surface 21d. The image lights GL11 and GL12 are reflected by the fourth reflection surface 21d at the same angle as the third reflection surface 21c, and are angled from the light emission surface OS to the second optical axis AX2 direction perpendicular to the light emission surface OS. The light is emitted as a parallel light beam with an inclination of θ ₁ .

The image lights GL21 and GL22 from the second display point P2 on the left side of the liquid crystal display device 32 pass through the lenses L1, L2, and L3 of the projection optical system 12 to be converted into parallel light beams, and the light incident surface of the light guide member 21 Incident on IS. The image lights GL21 and GL22 guided into the light guide member 21 repeat total reflection at equal angles on the first and second reflection surfaces 21a and 21b, and are finally emitted from the light exit surface OS as parallel light beams. . Specifically, the image lights GL21 and GL22 are reflected by the third reflecting surface 21c of the light guide member 21 as a parallel light beam, and then the first reflection of the light guide member 21 at the second reflection angle γ2 (γ2 <γ1). The light enters the surface 21a and is totally reflected (first total reflection). Thereafter, the image lights GL21 and GL22 enter the second reflection surface 21b and are totally reflected (second total reflection) while maintaining the second reflection angle γ2, and then enter the first reflection surface 21a again. Are totally reflected (third total reflection), are incident again on the second reflecting surface 21b and totally reflected (fourth total reflection), and are again incident on the first reflecting surface 21a and totally reflected. (5th total reflection). As a result, the image lights GL21 and GL22 are totally reflected five times on the first and second reflecting surfaces 21a and 21b and enter the fourth reflecting surface 21d. The image lights GL21 and GL22 are reflected by the fourth reflecting surface 21d at the same angle as the third reflecting surface 21c, and are angled from the light emitting surface OS to the second optical axis AX2 direction perpendicular to the light emitting surface OS. It is emitted as a parallel light beam by theta ₂ gradient.

  In FIG. 5, when the light guide member 21 is developed, a virtual first surface 121a corresponding to the first reflective surface 21a, and when the light guide member 21 is deployed, a virtual corresponding to the second reflective surface 21b. The 2nd surface 121b is drawn. By developing in this way, the image lights GL11 and GL12 from the first display point P1 pass through the first surface 121a twice after passing through the incident equivalent surface IS ′ corresponding to the light incident surface IS. It can be seen that the light passes through the surface 121b once, is emitted from the light exit surface OS, and enters the observer's eye EY, and the image lights GL21 and GL22 from the second display point P2 are incident corresponding to the light entrance surface IS. After passing through the equivalent surface IS ", it can be seen that it passes through the first surface 121a three times, passes through the second surface 121b twice, is emitted from the light exit surface OS, and enters the observer's eye EY. In other words, the observer observes the lens L3 of the projection optical system 12 existing in the vicinity of the two incident equivalent planes IS ′ and IS ″ at two different positions.

  6A is a diagram for conceptually explaining the display surface of the liquid crystal display device 32, and FIG. 6B is a diagram for conceptually explaining a virtual image of the liquid crystal display device 32 visible to an observer. FIGS. 6C and 6D are diagrams for explaining partial images constituting a virtual image. A rectangular image forming area AD provided in the liquid crystal display device 32 shown in FIG. 6A is observed as a virtual image display area AI shown in FIG. On the left side of the virtual image display area AI, a first projection image IM1 corresponding to a portion from the center to the right side of the image formation area AD of the liquid crystal display device 32 is formed. This first projection image IM1 is shown in FIG. ) As shown in FIG. Further, on the right side of the virtual image display area AI, a projection image IM2 corresponding to a portion from the center to the left side of the image formation area AD of the liquid crystal display device 32 is formed as a virtual image. This second projection image IM2 is shown in FIG. As shown in (D), the left half is a partial image.

  The first partial region A10 that forms only the first projected image (virtual image) IM1 in the liquid crystal display device 32 illustrated in FIG. 6A includes, for example, the first display point P1 at the right end of the liquid crystal display device 32. The image lights GL11 and GL12 that are totally reflected three times in total in the light guide portion B2 of the light guide member 21 are emitted. The second partial area A20 that forms only the second projection image (virtual image) IM2 in the liquid crystal display device 32 includes, for example, the second display point P2 at the left end of the liquid crystal display device 32, and the light guide member 21 guides the light. The image light GL21 and GL22 that are totally reflected five times in the portion B2 are emitted. Image light from the band SA extending vertically and sandwiched between the first and second partial areas A10 and A20 near the center of the image forming area AD of the liquid crystal display device 32 forms an overlapping image IS shown in FIG. 6B. doing. That is, the image light from the band SA of the liquid crystal display device 32 is a total of 5 in the first projection image IM1 formed by the image light GL11 and GL12 totally reflected three times in the light guide B2, and in the light guide B2. The second projected image IM2 formed by the image lights GL11 and GL12 that are totally reflected once is superimposed on the virtual image display area AI. If the light guide member 21 is precisely processed and a light beam accurately collimated by the projection optical system 12 is formed, the overlapping image IS is prevented from being displaced or blurred due to the superimposition of the two projection images IM1 and IM2. be able to.

[E. (Filter function)
Hereinafter, the function of the filter 50 disposed between the projection optical system 12 and the light guide device 20 will be described in detail.

  FIG. 7A is a chart for explaining a light distribution pattern of image light emitted from the image display device 11. The horizontal axis indicates the horizontal X-direction injection angle, and the vertical axis indicates the vertical Y-direction injection angle. As is apparent from the figure, the luminous flux emitted from the liquid crystal display device 32 of the image display device 11 has high brightness on the center side along the first optical axis AX1, but is inclined with respect to the first optical axis AX1. On the peripheral side, it can be seen that the brightness decreases rapidly as the emission angle increases. Note that the higher luminance in the vertical Y direction up to the periphery having a relatively large inclination is due to the fact that the sub-pixels of the liquid crystal display device 32 are vertically long.

  FIG. 7B is a diagram for explaining an example of a pixel array of the liquid crystal display device 32. In the illustrated example, pixels 23g having a substantially square outline are repeatedly arranged in a matrix on the liquid crystal display device 32. Each pixel 23g is composed of RGB sub-pixels 23s, and each sub-pixel 23s has a thin vertical profile. The image light GL emitted from such a liquid crystal display device 32 passes through the elongated opening of the sub-pixel 23s, and has relatively high luminance even when the emission angle increases in the vertical Y direction.

  The above situation applies not only to the light beam from the center of the liquid crystal display device 32 but also to the light beam from the periphery, and the image light GL emitted from the projection optical system 12 becomes darker as the periphery is away from the first optical axis AX1. Tend.

  Further, the image light GL propagated by the light guide member 21 of the light guide device 20 includes image light GL11 and GL12 totally reflected three times in the light guide B2, and total reflection five times in the light guide B2. Image light GL21 and GL22 to be present. Any of the image lights GL11, GL12, GL21, and GL22 have a propagation condition limit due to the shape limitation of the light guide member 21, and vignetting (periphery of the image light GL11, GL12 around the image) Dimming occurs due to (partial shading), and dimming occurs due to vignetting (partial shading) around the image by the image light GL21 and GL22 propagating in a mode with a large number of total reflections. Therefore, if the filter 50 does not exist, the periphery of the first projection image IM1 shown in FIG. 6C is considerably darker than the center, and the second projection shown in FIG. The periphery of the image IM2 is also considerably darker than the center.

  The filter 50 shown in FIG. 8A is an ND filter having a two-dimensional absorption distribution along the main surface 50a. For example, the filter 50 is centered in a pattern like a contour line CL shown in FIG. 8B. The absorption rate of the part is high and the absorption rate of the peripheral part is low. Such a filter 50 can compensate for the light distribution pattern of FIG. 7 and the spatial distribution of dimming during propagation through the light guide member 21, and the effective display area or virtual image display area AI shown in FIG. 6B. The luminance of the image displayed on the screen can be set substantially uniformly.

  FIG. 9A corresponds to the effective display area or the virtual image display area AI in FIG. 6B, and shows the luminance distribution of the image seen by the observer as a specific gray-scale distribution. FIG. 9B is a graph showing the luminance distribution in the AA cross section of FIG. As is clear from FIGS. 9A and 9B, by providing the filter 50, the luminance distribution in the effective display area or the virtual image display area AI is relatively uniform.

  FIG. 9C shows the luminance distribution of the comparative example as a specific light and shade distribution, and FIG. 9D is a graph showing the luminance distribution in the AA cross section of FIG. 9C. In this comparative example, the filter 50 is removed from the first display device 100A shown in FIG. As is clear from FIGS. 9C and 9D, when the filter 50 is not provided, the luminance distribution in the effective display area or the virtual image display area AI is the area of the pair of projection images IM1 and IM2 shown in FIG. Corresponding to the above.

[F. Others]
FIG. 10 is an enlarged view for explaining the reason why the light guide member 21 shown in FIG. The image light GL incident on a position near the ridge 121h of the light guide member 21 is reflected by the first reflecting surface 21a after being reflected by the third reflecting surface 21c, but the third after the reflection by the first reflecting surface 21a. It is reflected again by the reflecting surface 21c. Such unnecessary light HL as re-reflected light is not parallel to the original image light GL due to reflection on the third reflecting surface 21c, and is guided to an unexpected optical path, but a part of the unnecessary light HL is light emitting part B3. May be emitted from the light exit surface OS. That is, the unnecessary light HL generated at the ridge 121h becomes an unwanted ghost light GG, so it is desirable to remove it in advance. For this reason, the edge 121h is removed to provide a stray light blocking end surface 21h, thereby limiting the optical path of the unnecessary light HL.

  FIG. 11 is an enlarged view for explaining a modification of the light guide member 21 shown in FIG. In this case, an end surface 21 i that removes the ridge 121 i is provided on the fourth reflecting surface 21 d side of the light guide member 21. That is, the light guide member 21 has an 8-sided polyhedral outer shape. For example, a relatively high reflectance coat or rough surface is applied to the end surface 21i, and the light transmitting member 23 is also provided with a step that fits the end surface 21i. By providing such an end surface 21i, the regular image light GL propagating through the light guide member 21 is reflected twice or more by the fourth reflecting surface 21d and enters the observer's eye EY as unnecessary light HL, or 3 It is possible to prevent unnecessary light HL that is image light or the like passing through the light guide portion B2 with less than the number of reflections from being emitted to the outside through the light emission surface OS. That is, the end face 21i prevents unwanted light HL that is inclined with respect to the original image light GL through an unexpected path from becoming unwanted ghost light GG.

  In the above description, the total number of reflections of the image light GL11 and GL12 emitted from the first partial region A10 including the first display point P1 on the right side of the liquid crystal display device 32 by the first and second reflection surfaces 21a and 21b is calculated. The total number of reflections of the image light GL21 and GL22 emitted from the second partial area A20 including the second display point P2 on the left side of the liquid crystal display device 32 by the first and second reflection surfaces 21a and 21b is 5 in total. However, the total number of reflections can be changed as appropriate. That is, by adjusting the outer shape (that is, thickness t, distance D, acute angles α, β) of the light guide member 21, the total number of reflections of the image light GL11, GL12 is set to five times, and the total reflection number of the image light GL21, GL22 A total of seven times can be used. In the above description, the total number of reflections of the image lights GL11, GL12, GL21, and GL22 is an odd number. However, if the light incident surface IS and the light exit surface OS are arranged on the opposite side, that is, the light guide member 21. Is a parallelogram type in plan view, the total number of reflections of the image lights GL11, GL12, GL21, and GL22 is an even number.

[G. (Summary)
In the virtual image display device 100 according to the first embodiment described above, the image light GL reflected by the third reflecting surface 21c of the light incident portion B1 is totally reflected by the first and second reflecting surfaces 21a and 21b of the light guide portion. And is reflected by the fourth reflecting surface 21d of the light emitting part B3 and enters the observer's eye EY as a virtual image. At this time, the number of reflections of the first image light GL11 and GL12 emitted from the first partial region A10 including the first display point P1 of the image display device 11 in the light guide portion and the second display point P2 of the image display device 11 are displayed. Since the number of reflections of the second image light GL21 and GL22 emitted from the second partial region A20 including the light guide portion B2 is different, the angle width of the emission angle of the image light GL emitted from the light emission portion B3 is widened. Can take. That is, the image light GL from the different partial areas A10 and A20 in the image display device 11 can be taken in with a relatively wide viewing angle, and a large display size of the virtual image observed through the light emitting part B3 is ensured. be able to. In this way, by adopting a structure that takes out the image light GL with different number of reflections, the light emission part B3 can be enlarged so as to cover the pupil without making the light guide part B2 too thick, so the light emission part B3 It is no longer necessary to divide the pupil close to the pupil, a large eye ring diameter can be secured, and good see-through observation is also possible.

  In the virtual image display device 100 according to the first embodiment, the filter 50 is disposed between the projection optical system 12 and the light guide device 20 and changes the spatial distribution of the transmitted light amount. Even if an image as a virtual image formed by the optical device 20 has relatively large luminance spots, an image in which the luminance spots are suppressed can be displayed to an observer. Thereby, the virtual image displayed while enlarging the size of the virtual image displayed by the virtual image display apparatus 100 can be made into a high quality thing.

[Second Embodiment]
Hereinafter, the virtual image display device according to the second embodiment of the present invention will be described in detail with reference to the drawings. The virtual image display device according to the second embodiment is a partial modification of the virtual image display device 100 according to the first embodiment, and parts not specifically described are the same as those of the virtual image display device 100 according to the first embodiment. And

  As shown in FIG. 12, the filter 150 is bonded to the light incident surface IS of the light guide member 21.

  As shown in FIGS. 13A and 13B, the filter 150 is obtained by forming a metal reflective film 52 on a light-transmitting substrate 51, and the light of the light guide member 21 through an adhesive layer 61. Bonded to the injection surface OS. The adhesive layer 61 is a light transmission layer having a moderately lower refractive index than the light guide member 21. Specifically, when the refractive index of the light guide member 21 is 1.5, the refractive index of the adhesive layer 61 is set to 1.3 or less. Thereby, it is possible to prevent the image light GL propagated in the light guide member 21 from being attenuated without being totally reflected by the light exit surface OS or the inner surface of the first reflection surface 21a.

  As shown in FIG. 14A, the filter 150 is a micro-pattern type in which a light shielding part 50d having a light shielding property of approximately 100% is formed in a predetermined pattern with respect to a light transmitting part 50c having a light transmittance of approximately 100%. It is a filter. The light shielding part 50d is composed of a large number of circular areas AM arranged at random on the substrate 51, and corresponds to the metal reflection film 52 shown in FIG. By adjusting the density of the circular area AM on the substrate 51, the macroscopic transmittance at that position can be adjusted within a range of, for example, 50% to 90%, and the two-dimensional distribution or pattern of the transmittance can be adjusted. Can be formed. That is, the uneven brightness of the image light can be compensated by the two-dimensional transmittance distribution formed on the filter 150.

  FIG. 14B shows a modification of the filter 150 shown in FIG. In this case, the filter 250 is a micro-pattern type filter in which a transmissive portion 50f having substantially 100% transmittance is formed in a predetermined pattern with respect to the light shielding portion 50e having approximately 100% light shielding properties. The transmissive part 50f is composed of a large number of circular areas AM randomly arranged on the substrate 51, and the area excluding the circular area AM corresponds to the metal reflection film 52 shown in FIG. By adjusting the density of the circular area AM on the substrate 51, the macroscopic transmittance at the position can be adjusted, and a two-dimensional distribution or pattern of the transmittance can be formed. That is, the luminance unevenness of the image light GL can be compensated by the two-dimensional transmittance distribution formed on the filter 250. In addition, the size of the transmission part 50f provided in the filter 250 is 0.2 mm or more in order to suppress diffraction.

  In the case of the second embodiment, it is not necessary to adjust the absorptance and reflectance of the metal reflective film 52 constituting the filters 150 and 250, and the adjustment of the transmittance distribution of the filters 150 and 250 is simple and precise.

  In the second embodiment described above, it is not necessary to make the size of the circular area AM uniform. For example, the size of the circular area AM can be changed according to the position.

  In the second embodiment described above, the circular area AM formed by the metal reflective film 52 is merely an example, and the image light GL can be blocked or transmitted by an elliptical area, a rectangular area, or the like.

  Instead of forming the partial transmission portions 50c and 50f in the metal reflection film 52, the thickness of the metal reflection film 52 is locally changed, so that the metal reflection film 52 itself has a two-dimensional transmittance. A distribution can also be formed.

[Third Embodiment]
Hereinafter, a virtual image display device according to a third embodiment of the present invention will be described in detail with reference to the drawings. Note that the virtual image display device of the third embodiment is a partial modification of the virtual image display device 100 of the first or second embodiment, and the portions that are not particularly described are the same as the virtual image display device 100 of the first embodiment or the like. It shall be the same.

  As shown in FIG. 15, the filter 350 is bonded to the light exit surface OS of the light guide member 21. The filter 350 is an ND filter having a two-dimensional absorption rate distribution like the filter 50 in the first embodiment, but the absorption rate distribution is different from that of the filter 50 shown in FIG.

  The filter 350 has two low-transmittance regions as indicated by the contour line CL in FIG. Thereby, the luminance distribution as shown in FIGS. 9C and 9D can be substantially canceled. That is, the luminance unevenness of the image light GL can be compensated by the two-dimensional transmittance distribution formed on the filter 350.

  The filter 350 can be bonded to the light guide member 21 through a light transmission layer having a refractive index that is moderately lower than that of the light guide member 21. In addition, the filter 350 is not limited to the ND filter, and may be one in which a metal reflective film 52 is formed on a light-transmitting substrate 51 as shown in FIG. 13B of the second embodiment.

[Fourth Embodiment]
Hereinafter, a virtual image display device according to a fourth embodiment of the present invention will be described in detail with reference to the drawings. Note that the virtual image display device of the fourth embodiment is a partial modification of the virtual image display device 100 of the first or second embodiment, and the parts not specifically described are the same as those of the virtual image display device 100 of the first embodiment. Suppose that

  As shown in FIG. 17, a filter 450 is formed on the surface of the lens L3 closest to the light emission side of the projection optical system 12. The filter 450 can be an ND filter having a two-dimensional absorption distribution similar to the filter 50 in the first embodiment. Further, the filter 450 can be formed by forming the metal reflective film 52 on the surface of the lens L3, similarly to the filters 150 and 250 shown in FIG. 13B of the second embodiment. In this case, the lens L3 functions as the substrate 51 that supports the metal reflective film 52.

[Fifth Embodiment]
Hereinafter, a virtual image display device according to a fifth embodiment of the present invention will be described in detail with reference to the drawings. Note that the virtual image display device of the fifth embodiment is a partial modification of the virtual image display device 100 of the first or second embodiment, and the portions that are not particularly described are the same as the virtual image display device 100 of the first embodiment or the like. It shall be the same.

As shown in FIG. 18A, in the case of this embodiment, a filter 550 is provided on the third reflecting surface 21c of the light incident portion B1. As shown in FIG. 18B, the filter 550 is inserted inside the mirror layer 25 provided on the third reflecting surface 21c of the light incident part B1, and is sandwiched between the slope RS and the mirror layer 25. ing. The filter 550 can be an ND filter having a two-dimensional absorption distribution similar to the filter 50 in the first embodiment, and is bonded to the slope RS, for example. The filter 550 can also be an attenuation type reflection film.
In the case of the present embodiment, the image light GL reflected by the mirror layer 25 is corrected for luminance unevenness by reciprocating the filter 550 in the light incident part B1. It should be noted that the same luminance unevenness correction can be achieved by providing the reflectance distribution of the mirror layer 25 itself, and in this case, the mirror layer 25 functions as a filter.

[Sixth Embodiment]
Hereinafter, a virtual image display device according to a sixth embodiment of the present invention will be described in detail with reference to the drawings. Note that the virtual image display device of the sixth embodiment is a partial modification of the virtual image display device 100 of the first or second embodiment, and portions not specifically described are the same as those of the virtual image display device 100 of the first embodiment or the like. It shall be the same.

As shown in FIG. 19A, in the case of the present embodiment, a filter 650 is provided on the fourth reflecting surface 21d of the light emitting portion B3. As shown in FIG. 19 (B), the filter 650 is inserted inside the half mirror layer 28 attached to the fourth reflecting surface 21d of the light emitting portion B3, and between the inclined surface RS and the half mirror layer 28. The half mirror layer 28 is bonded to the light transmission member 23 via the adhesive layer 29. The filter 650 can be an ND filter having a two-dimensional absorption distribution similar to the filter 50 in the first embodiment, and is bonded to the slope RS, for example. The filter 650 can also be an attenuation type reflection film.
In the case of the present embodiment, the image light GL reflected by the half mirror layer 28 is corrected for luminance unevenness by reciprocating the filter 650 in the light emitting part B3. It should be noted that by providing the reflectance distribution of the half mirror layer 28 itself, the same luminance unevenness correction can be performed. In this case, the half mirror layer 28 functions as a filter.

[Modifications, etc.]
Although the present invention has been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the gist thereof. Such modifications are also possible.

  FIG. 20A is a diagram illustrating a modification of the light guide member 21 illustrated in FIG. In the above description, the image light propagating through the light guide member 21 is totally reflected at only the two reflection angles γ1 and γ2 with respect to the first and second reflection surfaces 21a and 21b. As shown in the light guide member 21 of the modification shown in FIG. 3, the image light GL31, GL32, and GL33 of the three components are allowed to be totally reflected at the reflection angles γ1, γ2, and γ3 (γ1> γ2> γ3). You can also. In this case, the image light GL emitted from the liquid crystal display device 32 is propagated in three modes and is synthesized at the position of the eye EY of the observer to become a virtual image. In this case, as shown in FIG. 20B, a total reflection projection image IM21 is formed, for example, three times on the left side of the virtual image display area or effective display area A0, and is closer to the center of the virtual image display area or effective display area A0. For example, a total reflection projection image IM22 is formed five times in total, and a total reflection projection image IM23 is formed seven times in total on the right side of the virtual image display area or effective display area A0.

  In the above embodiment, the see-through is given priority by setting the reflectance of the half mirror layer 28 provided on the fourth reflecting surface 21d of the light guide member 21 to 20%. However, the reflectance of the half mirror layer 28 is set to 50% or more. Priority can be given to light. Note that the half mirror layer 28 does not have to be formed on the entire surface of the fourth reflecting surface 21d, and can be formed only in a part of the necessary region. The half mirror layer 28 can also be formed on the third surface 23 c of the light transmission member 23.

  The shape of the light transmissive member 23 is not limited to the shape in which the light guide member 21 extends laterally, that is, in the X direction, and may include a portion that is extended so as to sandwich the light guide member 21 from above and below.

  In the above embodiment, the illumination light SL from the illumination device 31 is not particularly directed, but the illumination light SL can be provided with directivity corresponding to the position of the liquid crystal display device 32. Thereby, the liquid crystal display device 32 can be efficiently illuminated, luminance unevenness due to the position of the image light GL can be reduced, and the burden on the filters 50, 150, 250, 350, 450, 550, and 650 can be reduced.

  In the above embodiment, the display brightness of the liquid crystal display device 32 is not particularly adjusted, but the display brightness can be adjusted according to the range and overlap of the projection images IM1 and IM2 as shown in FIG. . Also by this, the excessive burden of the filters 50, 150, 250, 350, 450, 550, 650 can be reduced.

  In the above-described embodiment, the transmissive liquid crystal display device 32 or the like is used as the image display device 11. However, the image display device 11 is not limited to the transmissive liquid crystal display device 32, and various devices can be used. . For example, a configuration using a reflective liquid crystal display device is possible, and a digital micromirror device or the like can be used instead of the liquid crystal display device 32. Further, as the image display device 11, a self-luminous element represented by an LED array, an OLED (organic EL), or the like can be used.

  In the virtual image display device 100 of the above-described embodiment, the image forming device 10 and the light guide device 20 are provided one by one corresponding to both the right eye and the left eye, but either the right eye or the left eye. Only the image forming apparatus 10 and the light guide device 20 may be provided for only one eye.

  In the above embodiment, the first optical axis AX1 passing through the light incident surface IS and the second optical axis AX2 passing through the light incident surface IS are parallel, but these optical axes AX1 and AX2 are made non-parallel. You can also.

  In the above description, the virtual image display device 100 has been specifically described as being a head-mounted display, but the virtual image display device 100 can be modified to a head-up display.

  In the above description, in the first and second reflecting surfaces 21a and 21b, image light is totally reflected and guided by the interface with air without applying a mirror, a half mirror, or the like on the surface. The total reflection includes reflection formed by forming a mirror coat or a half mirror film on the whole or a part of the first and second reflection surfaces 21a and 21b. For example, after the incident angle of the image light satisfies the total reflection condition, the first and second reflection surfaces 21a and 21b are subjected to mirror coating or the like to reflect substantially all the image light. Cases are also included. In addition, as long as image light with sufficient brightness can be obtained, the first and second reflecting surfaces 21a and 21b may be entirely or partially coated with a somewhat transmissive mirror.

  In the above description, the light guide member 21 extends in the horizontal direction in which the eyes EY are arranged. However, the light guide member 21 can be extended in the vertical direction. In this case, the optical panels 110 are arranged in parallel, not in series.

  DESCRIPTION OF SYMBOLS 10 ... Image forming apparatus, 11 ... Image display apparatus, 12 ... Projection optical system, 20 ... Light guide apparatus, 21 ... Light guide member, 21a, 21b, 21c, 21d ... 1st-4th reflective surface, 21e ... Upper surface, 21f ... lower surface, 21h, 21i ... end face, 23 ... light transmitting member, 23a, 23b, 23c ... surface, 25 ... mirror layer, 27 ... hard coat layer, 28 ... half mirror layer, 31 ... lighting device, 32 ... liquid crystal display Device 32b ... Display area 34 Drive controller 50, 150, 250, 350, 450 ... Filter 51 On substrate 52 Metal reflective film 100 Virtual image display device 100A 100B Display device 110 ... Optical panel, 121 ... Frame, 131, 132 ... Drive part, AX1 ... First optical axis, AX2 ... Second optical axis, B1 ... Light incident part, B2 ... Lead Light part, B3: Light emitting part, B4: Transparent part, EY ... Eye, FS ... Flat surface, GL ... Image light, GL '... External light, GL11, GL12, GL21, GL22 ... Image light, IM1, IM2 ... Projection Image: IS: Light incident surface, L1, L2, L3: Lens, OS: Light exit surface, P1: Display point, P2: Display point, SL: Illumination light.

In order to solve the above problems, a virtual image display device according to the present invention includes (a) an image display device that forms image light, (b) a projection optical system that makes the image light emitted from the image display device enter, c) a light guide part, a light incident part for causing image light to enter the light guide part, and image light guided by the light guide part by a reflective film having light transmittance including a metal reflective film or a dielectric multilayer film. And a light guide device that enables observation of image light through the light emission portion and observation of external light , and (d) the light guide portion , Having a first reflection surface and a second reflection surface that are arranged in parallel to each other and enable light guide by total reflection; (e) arranged between the projection optical system and the light incident portion , and a central portion and a periphery The image emitted from the image display device has a two-dimensional transmittance distribution that differs in transmittance from part to part. And a filter for compensating the luminance distribution of the image light .

In the virtual image display device, the image light incident on the light incident portion is propagated while being totally reflected by the first and second reflection surfaces of the light guide portion, and includes a light reflecting portion including a metal reflective film or a dielectric multilayer film. Is reflected by the reflective film having the property and enters the observer's eye as a virtual image. In this case, the effective pupil diameter can be increased, and the displayed virtual image can be made large in size with high quality. In addition, since the light emitting portion has a light-transmissive reflective film including a metal reflective film or a dielectric multilayer film, see-through observation is possible through the reflective film , and a virtual image is superimposed on the external image. Can be observed. Further, in the virtual image display device, the filter is disposed between the projection optical system and the light incident portion , and has a two-dimensional transmittance distribution in which the transmittance is different between the central portion and the peripheral portion. Since the brightness distribution of the emitted image light is compensated, the image as a virtual image formed by the projection optical system and the light guide device has a relatively large brightness spot without affecting see-through observation. In addition, an image in which the luminance unevenness is suppressed can be displayed to the observer.

Claims (11)

An image display device for forming image light;
A projection optical system for making the image light emitted from the image display device incident;
A light guide unit; a light incident unit that causes the image light to enter the light guide unit; and a light emission unit that emits the image light guided by the light guide unit to the outside. A light guide device that enables observation of the image light through,
The light guide unit has a first reflection surface and a second reflection surface that are arranged in parallel to each other and enable light guide by total reflection,
The light incident portion has a third reflecting surface that forms a predetermined angle with respect to the first reflecting surface;
The light emitting portion has a fourth reflecting surface that forms a predetermined angle with respect to the first reflecting surface,
A light transmission surface that has a light transmission surface bonded to the fourth reflection surface of the light emitting portion via the reflection surface, and further comprises a light transmission member that constitutes a fluoroscopic portion in combination with the light guide device;
A virtual image display device comprising: a filter that is disposed between the projection optical system and the light guide device and that changes a spatial distribution of a passing light amount.   The virtual image display device according to claim 1, wherein the filter is an ND filter that reduces light by absorption.   The virtual image display device according to claim 1, wherein the filter is a filter in which a metal reflective film is formed on a light-transmitting substrate.   4. The virtual image display device according to claim 1, wherein the filter is a micro-pattern type filter in which a transmission part and a light-shielding part are formed in a predetermined pattern. 5.   The virtual image display device according to claim 4, wherein each of the transmissive portions forming the predetermined pattern of the filter has a size of 0.2 mm or more.   The virtual image display device according to any one of claims 1 to 5, wherein the filter is provided between the projection optical system and a light incident surface of the light incident portion. The light guide device is a block-shaped member in which the light guide unit, the light incident unit, and the light emitting unit are integrated,
The virtual image display according to claim 6, wherein the filter is bonded to the light incident surface of the light guide device via a light transmission layer having a refractive index lower than the light guide device by a predetermined refractive index or more. apparatus.   The virtual image display device according to claim 6, wherein the filter is formed on a surface of a lens constituting the projection optical system.   The virtual image display device according to claim 1, wherein the filter is disposed on a light emission surface of the light emission unit.   6. The virtual image display device according to claim 1, wherein the filter is attached to at least one of the second reflecting surface and the third reflecting surface. 7.   The virtual image display device according to claim 1, wherein the filter has a transmittance distribution that varies depending on a position.

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