JP6010889B2 - Virtual image display device - Google Patents

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.

  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 in which image light from a display element is guided to an observer's pupil by a light guide plate. In order to superimpose light and external light, one using a see-through optical system has been proposed (see Patent Document 1).

  However, particularly in the case of a see-through optical system such as Patent Document 1, the optical member constituting the head-mounted display receives ultraviolet rays contained in external light, so that the transmittance of light having a short wavelength gradually decreases in the optical member. The phenomenon of yellowing may occur. If such yellowing occurs in the part that guides the image light like the inside of the optical member, not only the external light but also the image light that passes through the optical member is colored, and the color balance of the projected image may be lost. As a result, the transmittance of the image light is lowered.

  In order to prevent the yellowing as described above from occurring inside the optical member, a material that absorbs ultraviolet light is mixed, and a plastic lens material (see Patent Documents 2 to 4 etc.) that hardly yellows is used. It is also conceivable to form a hard coat layer which is a base material or a surface coat layer of the light guide plate. However, in this case, even if it is possible to prevent ultraviolet rays from entering the inside of the base material, if the surface side of the base material or the surface coat itself that receives a relatively large amount of ultraviolet light turns yellow, the yellowed surface When the image light passes through the portion on the side, there is a possibility that the deterioration over time such as coloring of the image light and a decrease in transmittance may become remarkable.

JP 2010-224473 A JP 2002-182001 A JP 2004-345123 A JP 2008-90327 A

  An object of this invention is to provide the virtual image display apparatus which can suppress aged deterioration by the influence of an ultraviolet-ray and can form a favorable image.

  In order to achieve the above object, a virtual image display device of the present invention includes (a) an image display device that forms image light, (b) a projection optical system that forms a virtual image by image light emitted from the image display device, and (C1) a light incident part that captures image light that has passed through the projection optical system, (c2) a light guide part that guides image light captured from the light incident part, and (c3) image light that has passed through the light guide part. (C) a light guide device having an external light extraction unit, and (d) an ultraviolet light that is disposed so as to cover the surface of the light guide device and is included in the light traveling from the outside to the light guide device It further has an ultraviolet light absorber that absorbs these components.

  In the virtual image display device, the light guide device is covered with an ultraviolet light absorbing material, and the ultraviolet light absorbing material absorbs an ultraviolet light component in advance from outside light toward the light guide device, thereby guiding the light. The influence of the ultraviolet light component on the apparatus can be suppressed. That is, the virtual image display device can form a good image while suppressing deterioration over time such as coloring due to the influence of ultraviolet rays and a decrease in transparency. Here, as for the ultraviolet absorber, in addition to the case where it is included in a material provided separately from the light guide device, for example, when it is mixed with a film member attached to the surface of the light guide device, Various modes are possible, such as when included in a coating material that coats the surface of the light guide.

  In a specific aspect of the present invention, the light emitting unit includes a transflective film that reflects the image light that has passed through the light guide unit and extracts the light to the outside, and allows the external light to pass through and allows observation of the external light. . In this case, see-through observation in which the image light and the external light are superimposed can be performed by having the semi-transmissive reflective film.

  In another aspect of the present invention, the light guide section includes first and second total reflection surfaces that extend opposite to each other and guide image light by total reflection, and the light guide device includes at least first and second total reflection surfaces. It has a hard coat layer provided along with the light guide surface that contributes to the light guide of the image light including the reflective surface. In this case, the hard coat layer can prevent the light guide surface from being damaged and facilitate the removal of dirt, thereby preventing a reduction in the resolution of the image. Further, the hard coat layer is protected by the ultraviolet light absorbing material, and deterioration is suppressed.

  In yet another aspect of the present invention, the light guide device is covered from the surface side, and the amount of transmitted external light incident thereon is adjusted, and a shade member including an ultraviolet light absorbing material is further included. Here, the shade member only needs to be blocked by absorbing the ultraviolet light component, and is not limited to one having a relatively high transmittance of the visible light component, but various members that are appropriately determined as necessary. For example, the transmittance of the visible light component may be approximately 100%. In this case, the ultraviolet light component contained in the external light toward the light guide device can be absorbed by the shade member so as not to reach the light guide device. The shade member can be detachable from the light guide device.

  In still another aspect of the present invention, the light guide device includes an ultraviolet curing member that is cured by absorbing ultraviolet light. In this case, the optically transparent optical member constituting the light guide device can be formed with high accuracy at a relatively low temperature by photopolymerization or the like. Moreover, these optical members are protected by the ultraviolet light absorbing material and can suppress deterioration.

  In still another aspect of the present invention, the ultraviolet light absorbing material transmits visible light belonging to a wavelength band longer than the ultraviolet light out of the passing light with a substantially constant transmittance. In this case, the viewer can be made to recognize the ultraviolet light absorbing material without destroying the color balance of the visible light component of the external light.

  In still another aspect of the present invention, the ultraviolet light absorbing material makes the transmittance of ultraviolet light smaller than the transmittance of light in the visible light wavelength region band. In this case, not only the ultraviolet light is removed to protect the light guide device and the eyes of the observer, but also the observer can easily recognize visible light.

  In still another aspect of the present invention, the light guide device includes a light incident part, a light guide part, and a light emission part, and a see-through part that enables observation of external light by joining the light guide member. And a light transmitting member whose surface side is covered with an ultraviolet light absorbing material. In this case, with respect to the light transmitting member that constitutes the see-through portion for see-through together with the light guide member, it is possible to suppress deterioration over time such as coloring due to the influence of ultraviolet rays and a decrease in transparency, thereby forming a good image.

  In still another aspect of the present invention, 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, and the light incident unit is the first reflection surface. A third reflective surface having a predetermined angle with respect to the surface is provided, and the light emitting portion has a fourth reflective surface having a predetermined angle with respect to the first reflective surface. 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 to be an observer as a virtual image. Incident on the eyes. In addition, by making the light incident part, the light guide part, and the light emitting part into an integral block-like member, the light guide device can be formed with high accuracy using the injection molding technique. Can be protected from ultraviolet light components by the ultraviolet light absorbing 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 which shows the structure and attachment of a shade member, (B) is a figure for demonstrating the ultraviolet absorption by a shade member. (C) is a figure which shows the attachment of the shade member of a modification, (D) is a figure for demonstrating the ultraviolet absorption by the shade member of a modification. It is a graph which shows the transmittance | permeability characteristic of an ultraviolet light absorber. (A) is a figure which shows the structure and attachment of the shade member of the virtual image display apparatus of 2nd Embodiment, (B) is a figure for demonstrating the ultraviolet absorption by the shade member of a modification. (A) is sectional drawing which shows the virtual image display apparatus which concerns on 3rd Embodiment, (B) and (C) are the front views and top views of a light guide device. It is a schematic diagram explaining the optical path of image light. It is sectional drawing explaining the junction part containing a half mirror layer. (A) is sectional drawing which shows the virtual image display apparatus which concerns on 4th Embodiment, (B) and (C) are the front views and top views of a light guide device. It is a schematic diagram explaining the optical path of image light. It is sectional drawing explaining the junction part containing a half mirror layer. It is sectional drawing explaining the other example of the junction part containing a half mirror layer. (A) is a figure which shows the modification of the 1st display apparatus which comprises a virtual image display apparatus, (B) is a figure which shows another modification of a 1st display apparatus. It is a figure which shows another modification of the 1st display apparatus which comprises a virtual image display apparatus.

  Hereinafter, a virtual image display device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[A. Appearance of virtual image display device)
A virtual image display device 100 according to the 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. It is possible to make the observer observe the external image with see-through. The virtual image display device 100 includes an optical panel 110 that covers the eyes of an observer, a frame 121 that supports the optical panel 110, a shade member 29 that is a protective member that detachably covers the optical panel 110 from the front side, and a frame 121. Of these, first and second drive portions 131 and 132 are provided that are added to a portion from the front cover portion adjacent to the shade member 29 to the rear vine portion (temple). 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. The shade member 29 is a member that adjusts the amount of transmitted external light, and is detachable. The virtual image display device 100 can be used even when the shade member 29 is detached.

[B. Display device structure]
As shown in FIG. 2A and the like, the first display device 100A includes an image forming device 10 and a light guide device 20. 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.

  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 reflective surface 21 a, a second reflective surface 21 b, a third reflective surface 21 c, and a fourth. 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, and third reflecting surfaces 21a, 21b, and 21c and the fourth reflecting surface 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. 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 is formed of a resin material that exhibits high light transmittance in the visible range. The light guide member 21 uses a block-shaped member integrally molded by injection molding as a main body portion 20a, and the main body portion (block-shaped member) 20a, for example, injects a heat or photopolymerization type resin material into a molding die. It is formed by heat curing or photocuring. As described above, the light guide member 21 has the main body portion 20a as a base material integrally formed, but functionally, the light guide member 21 can be divided into the light incident part B1, the light guide part B2, and the light emission 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 has a rectangular outline, and a mirror layer that is a 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 over the entire rectangular area. 25. The mirror layer 25 is formed by forming a film on the slope RS of the main body portion 20a of the light guide member 21 by vapor deposition of aluminum or the like. 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.

  The light guide B2 has first and second reflecting surfaces 21a and 21b that totally reflect the image light bent by the light incident portion B1 as two planes that face each other and extend parallel to the XY plane. Yes. 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. It is formed by forming a hard coat layer 27 which is a surface coat layer. The hard coat layer 27 is formed on the exposed portion of the virtual image display device 100. The hard coat layer 27 forms the first and second reflecting surfaces 21a and 21b, and prevents the exposed portion from being damaged and facilitates removal of dirt. To prevent a decrease in the resolution of the video. The hard coat layer 27 can be formed by, for example, applying an ultraviolet curable coating agent on the flat surface of the main body portion 20a on the surface by dipping or the like, and then curing the coating material by ultraviolet irradiation. That is, the hard coat layer 27 can be composed of an ultraviolet curing member obtained by curing the coating material.

  Here, as shown in a partially enlarged view in FIG. 2A, for example, when total reflection on the first and second reflecting surfaces 21a and 21b is caused on the surface side of the hard coat layer 27, one time In total reflection, the component of the image light GL passes through the hard coat layer 27 twice. Therefore, in the case of such a configuration, it is particularly important to suppress yellowing of the hard coat layer 27 in order to prevent deterioration of image light.

  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. By repeating this operation thereafter, the image light is guided to the leading light direction on the back side of the light guide device 20 as a whole, that is, to the + Z side where the light emitting part B3 is provided. 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 light emission part B3 is a triangular prism-shaped part, and has a light emission surface OS that is a part of the first reflection surface 21a and a fourth reflection surface 21d that faces the light emission surface OS. 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, reflects the image light GL that has entered through the first and second reflecting surfaces 21a and 21b, emits the light to the outside of the light emitting part B3, and emits external light GL ′. A half mirror layer 28 for transmission is provided in a rectangular partial region disposed in the center of the fourth reflecting surface 21d. The half mirror layer 28 is a transflective film having light transmittance. The half mirror layer (semi-transmissive reflective film) 28 is formed by forming a metal reflective film or a dielectric multilayer film of, for example, silver on the inclined surface RR constituting the fourth reflective surface 21d of the light guide member 21. The The reflectance of the half mirror layer 28 with respect to the image light GL is set to 10% or more and 50% or less 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. The component of the image light GLx that has passed through the fourth reflecting surface 21d is incident on the light transmitting member 23 and is not used to form an image.

  The light transmissive member 23 includes a main body portion 23s having the same refractive index as the main body portion 20a 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 are formed by forming a hard coat layer 27, which is a surface coat layer, on the surface of the main body portion 23s, like the first and second reflection surfaces 21a and 21b. , Extending 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 has a wedge-shaped member 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-shaped member integrally formed by injection molding as a main body portion 23s. The main body portion 23s is formed by, for example, injecting heat or a photopolymerization type resin material into a molding die. It is formed by thermosetting or photocuring.

  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 light 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 by the surface 23c is equal to the angle β formed by the first reflecting surface 21a and the third reflecting surface 21c of the light guide member 21.

  The light transmission member 23 and the light guide member 21 constitute a see-through portion B4 at the joint portion between them and the vicinity thereof. That is, 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 part B2 of the light guide member 21. . The third surface 23c can also transmit the external light GL ′ with high transmittance. However, since the fourth reflecting surface 21d of the light guide member 21 includes the half mirror layer 28, the center of the third surface 23c. The external light GL ′ passing through the region is attenuated 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%. In the state where the shade member 29 is mounted, the external light GL ′ is dimmed in advance before passing through the light transmission member 23 and the light guide member 21, and the observer is, for example, 80%. The external light GL ′ dimmed to a fraction is observed.

[C. Overview of optical path of image light)
FIG. 3A is a diagram illustrating an optical path in the first direction D1 or the unconfined direction DW1 corresponding to the longitudinal section CS1 of the liquid crystal display device 32. 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 incident on the observer's eye EY in a state of a parallel light beam, tilted 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 parallel light flux with an inclination 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. 3B is a diagram illustrating an optical path in the second direction D2 or the confinement direction DW2 corresponding to the cross section CS2 of the liquid crystal display device 32. In the cross section CS2 along the second direction D2, that is, the XZ plane (the unfolded X′Z ′ plane), of the image light emitted from the liquid crystal display device 32, toward the display region 32b indicated by the alternate long and short dash line in the figure. The component emitted from the first display point P1 on the right end side (+ X side) is the image light GL1, and from the second display point P2 on the left end side (−X side) toward the display region 32b indicated by the two-dot chain line in the drawing. Let the emitted component be image light GL2.

The image light GL1 from the first display point P1 on the right side is converted into a parallel beam by the projection optical system 12, and along the developed optical axis AX ′, the light incident part B1, the light guide part B2, and through the light exit portion B3, a parallel light beam state with respect to the observer's eye EY, incident inclined from right angles theta _1. On the other hand, the image light GL2 from the second display point P2 on the left side is converted into a parallel light flux 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 emitting part B3 and enters the observer's eye EY in a state of a parallel light beam with an angle θ ₂ (| θ ₂ | = | θ ₁ |) inclined from the left direction. 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.

In the second direction D2 or the confinement direction DW2, that is, in the lateral direction, the image light GL1 and GL2 are folded back by reflection in the light guide member 21, and the number of reflections is different. It is expressed discontinuously in the optical member 21. 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. Incidentally, considering that the number of reflections light guide member within 21 of both the image light GL1, GL2 are different from each other, the exit angle theta ₁ of the right side of the image light GL1 _'the exit angle theta ₂ of the left side of the image light GL2' Is set to something different.

  As described above, the image lights GLa, GLb, GL1, and GL2 incident on the observer's eye EY are virtual images from infinity, and the liquid crystal display device 32 has the vertical first direction D1 or the unconfined direction DW1. The formed image is upright, and the image formed on the liquid crystal display device 32 is reversed with respect to the second horizontal direction D2 or the confinement direction DW2.

  In the virtual image display device 100 having the see-through configuration as described above, the exposed portion through which external light is transmitted increases, so that the light guide member 21 and other light-transmitting optical members constituting the virtual image display device 100 are external. By passing the ultraviolet light component contained in the light GL ′, there is a possibility that the light transmittance will be lowered due to yellowing with age. For example, the hard coat layer 27 constituting the virtual image display device 100 is an important optical member for keeping the see-through in a good state on the surface of the light guide member 21 or the light transmission member 23. It is formed by depositing the agent by dipping. Therefore, it is conceivable to use an ultraviolet curable material formed of an ultraviolet curable material as a coating agent for these members 21 and 23. Further, the main body portion 20a of the light guide member 21 and the main body portion 23s of the light transmission member 23 may also be formed of an ultraviolet curing member formed by curing an ultraviolet curing material as a raw material. Since the ultraviolet curing member has a property of curing when the ultraviolet curing material as a raw material absorbs ultraviolet rays, there is a possibility that yellowing may progress over time. From the above, it is a very important issue to protect the light-transmitting optical members constituting the virtual image display device 100 such as the hard coat layer 27 and the main body portion 20a from ultraviolet light components. In this embodiment, when the shade member 29 shown in FIG. 1 includes an ultraviolet light absorbing material that absorbs an ultraviolet light component, the light-transmitting optical material that constitutes the virtual image display device 100 such as the hard coat layer 27 and the main body portion 20a. The member is accurately protected from ultraviolet light.

[D. (Shade member structure and attachment to light guide member)
Hereinafter, the structure of the shade member 29 and attachment to the light guide member 21, that is, the optical panel 110 will be described with reference to FIG. As shown in the side cross-sectional views of FIGS. 3A and 3B, the shade member 29 has a U-shape when viewed in cross section. As described above, the shade member 29 covers the optical panel 110 in FIG. 1, that is, the light guide device 20 in FIG. 3A from the second reflecting surface 21b side, and adjusts the amount of transmitted external light. It has a certain degree of light transparency and is detachable. The virtual image display device 100 can be used with the shade member 29 attached or removed. As a specific usage mode of the shade member 29, for example, when the shade member 29 has a certain degree of light shielding property, the usage environment of the virtual image display device 100 is bright and dark, or the image by the image light and the external environment It can be attached or removed according to the request of the observer as to which of these should be emphasized. In the present embodiment, in particular, the shade member 29 is composed of an ultraviolet light absorbing member UA formed of an ultraviolet light absorbing material or a material (ultraviolet light absorbing material) mixed with the material. Further, the shade member 29 can be replaced. When the shade member 29 is deteriorated, the shade member 29 can be replaced with a new one. The shade member 29 can be replaced with a member having a different transmittance according to the application.

  Here, various materials can be considered as the ultraviolet light absorbing material used for the ultraviolet light absorbing member UA of the shade member 29, that is, the ultraviolet light absorbing material as the raw material of the ultraviolet light absorbing member UA. Specifically, for example, a resin composition disclosed in JP-A-2002-182001 (Patent Document 2), that is, an epoxy (meth) acrylate, a specific polybutylene glycol di (meth) acrylate, a specific having an aromatic ring Containing a raw material monomer composed mainly of a mono (meth) acrylate having a structure and other polymerizable monomers, a benzotriazole-based ultraviolet absorber having a specific structure, and a photopolymerization initiator having absorption characteristics in the visible light region Can be used as the material of the ultraviolet light absorbing member UA. Further, for example, for a raw material composition disclosed in JP-A-2004-345123 (Patent Document 3), that is, a monomer composition containing a polymerizable monomer containing a compound such as an episulfide or a polyisocyanate compound as a main component. A resin composition obtained by dissolving a benzotriazole ultraviolet absorber having a particle diameter of 500 μm or less as an ultraviolet absorber and then polymerizing can also be used as the material of the ultraviolet light absorbing member UA. By using such a material, the ultraviolet light absorbing member UA can have sufficient ultraviolet absorptivity and relatively hardly yellow.

  FIG. 4 shows the transmittance when an ultraviolet absorber is mixed in the shade member 29. In this example, in the visible light wavelength range (400 nm to 650 nm), in order to reduce the intensity of the external light GL ′ and make the image light, that is, the image light GL easy to see, the transmittance is about 10%. In this example, the thickness of the shade member 29 in the transmission direction of the external light GL ′ is 2 mm. Curve C1 does not contain an ultraviolet absorber, and the transmittance in the ultraviolet region (350 nm to 400 nm) is higher than the transmittance in the visible light region. By introducing an ultraviolet absorber into this material, as shown by curve C2, the transmittance in the visible light region is not changed, and the transmittance in the ultraviolet region is reduced to 20% or less. In comparison, it can be about 3/4.

  Hereinafter, returning to FIG. 3A and the like, the attachment structure of the shade member 29 will be described. As shown in FIG. 3A, the shade member 29 covers the second reflecting surface 21b side of the light guide member 21, and functions as a main part 29x that functions as a cover, and the upper and lower parts of the main part 29x. A pair of wall portions 29y, 29y extending from the ends and covering the upper surface 21e and the lower surface 21f side of the light guide member 21, a pair of claw portions 29a, 29a formed at the tips of the wall portions 29y, 29y, and the wall portions 29y, And a pair of convex portions 29b and 29b formed on the root side of 29y.

  As shown in FIG. 3A, the shade member 29 is pressed from the direction of the arrow AW on the opposite side of the light guide member 21 from the observer's eye EY side, that is, the second reflecting surface 21b side. The claw portion 29 a provided at the tip of the wall portion 29 y is locked so as to be hooked on the light guide member 21, so that it can be attached to the light guide member 21. That is, as shown in FIG. 3B, the shade member 29 has nail on the peripheral portion SS that is not optically used on the first reflecting surface 21 a located on the observer's eye EY side of the light guide member 21. The part 29a is hooked and locked. Accordingly, the shade member 29 is in a state of covering the entire second reflection surface 21b located on the opposite side of the eye EY in the light guide member 21, and the outside world facing the light guide member 21 from the side opposite to the eye EY of the observer. Among the light GL ′, a certain proportion of the visible light component VR is allowed to pass while the ultraviolet light component UV is absorbed. That is, the shade member 29 absorbs the ultraviolet light component UV before reaching the light guide member 21, and protects the main body portion 20a and the hard coat layer 27 constituting the light guide member 21 from the ultraviolet light component UV. It has become.

  Moreover, the shade member 29 shown in FIG. 3A can be returned to the state where it is removed from the light guide member 21 by releasing the locking by the claw portion 29a provided at the tip of the flexible wall portion 29y. . That is, the shade member 29 is detachable from the light guide member 21 and is attached to the optical panel 110 including the light guide member 21 to protect the optical panel 110. For example, the shade member 29 is yellowed over time. However, only the shade member 29 can be replaced.

  The pair of convex portions 29b and 29b are positioning portions for providing a space GP between the main portion 29x of the shade member 29 and the hard coat layer 27 on the second reflecting surface 21b side. The projections 29b and 29b can ensure that the main portion 29x is not in direct contact with the hard coat layer 27 of the light guide member 21 and prevent the surface of the light guide member 21 from being damaged. It can be something that has no effect.

  Further, the transmittance or shading rate of the visible light component VR by the shade member 29 is appropriately determined as necessary, and the shading member 29 may have almost no shading property with a transmittance of approximately 100%. That is, the shade member 29 only needs to be blocked by absorbing the ultraviolet light component UV, and it does not matter whether the transmittance of the visible light component VR is high or low.

  As described above, in the present embodiment, the light guide device 20 is covered with the shade member 29 including the ultraviolet light absorbing member UA on the second reflecting surface 21b side which is the surface side, and the shade member 29 is the light guide device 20. The influence of the ultraviolet light component UV on the light guide device 20 can be suppressed by preliminarily absorbing the ultraviolet light component UV in the external light that travels toward the light source. That is, the virtual image display device 100 can form a good image by suppressing deterioration over time due to the influence of ultraviolet rays in the optical panel 110 including the light guide member 21 and the like. In the above case, the shade member 29 absorbs the ultraviolet light component UV, and as a result, the observer's eye EY is also protected from the ultraviolet light component UV.

  FIG. 3C and FIG. 3D are diagrams illustrating another example of the virtual image display device according to the present embodiment. In this example, the shade member 29 does not have the ultraviolet light absorbing member UA inside, but the ultraviolet light absorbing member UA is provided on the surface 29n located on the opposite side of the light guide device 20 in the shade member main body 29m. Yes. Also in this case, yellowing of each optical component of the light guide device 20 can be prevented by absorbing the ultraviolet light component UV by the ultraviolet light absorbing member UA. In addition, for example, when the ultraviolet light absorbing member UA is a film-like member that can be attached and detached, the ultraviolet light absorbing member UA may be replaced with a new one when it deteriorates over time. Moreover, as long as it can prevent yellowing of each optical component of the light guide apparatus 20, you may provide the ultraviolet light absorption member UA in places other than the above, for example, FIG.3 (C) and FIG.3 (D) ), The ultraviolet light absorbing member UA may be provided on the side facing the second reflecting surface 21b of the light guide device 20 in the shade member main body 29m, that is, on the back side of the shade member 29. In addition, the ultraviolet light absorbing member UA is provided only in the portion of the light guide device 20 that is largely involved in yellowing, and the ultraviolet light absorbing member UA is not provided in a place where there is little or no influence of yellowing. Also good.

  Further, the ultraviolet light absorbing member UA can be constituted by a laminated film or the like. That is, for example, by forming the surface of the shade member 29 with a multilayer film, this can be made the ultraviolet light absorbing member UA. In this case, the material constituting each layer of the laminated film is an ultraviolet light absorbing material that is a raw material of the ultraviolet light absorbing member UA.

  Further, instead of the configuration having the flexible wall portion 29y and the claw portion 29a provided at the tip thereof as in the shade member 29, a protective sheet made of a thin plastic sheet containing an ultraviolet absorber is used. It is good also as a structure which affixes or mounts | wears. That is, for example, ultraviolet light may be absorbed by providing a plastic sheet that is fixed by disposing screws, grooves, claws, and the like on the side surface of the light guide device 20 and covers the front surface of the light guide device 20.

[Second Embodiment]
The virtual image display device according to the second embodiment will be described below. The virtual image display device according to the present embodiment is a modification of the virtual image display device 100 according to the first embodiment, and is the same as the first virtual image display device 100 unless otherwise described.

  5A and 5B are diagrams illustrating an example of the virtual image display device according to the second embodiment, and the side corresponding to FIGS. 3A and 3B of the first embodiment. It is sectional drawing. In this example, the shade member 29 does not include the ultraviolet light absorbing member UA, and the ultraviolet light absorbing member UA is separately provided so as to cover the entire second reflecting surface 21b.

  In this case, regardless of the presence or absence of the detachable shade member 29, the ultraviolet light component UV contained in the external light GL ′ is absorbed by the ultraviolet light absorbing member UA, so that each optical component of the light guide device 20 is yellowed. Can be prevented. On the other hand, the visible light component VR of the external light GL ′ reaches the observer's eye EY by passing a certain amount.

  As for the configuration of the ultraviolet light absorbing member UA as described above, for example, an ultraviolet absorbing film member mixed with a raw material ultraviolet absorbing material is attached to the surface of the light guide device 20 as the ultraviolet light absorbing member UA. Can be considered. Further, the surface of the light guide device 20 may be directly coated with an ultraviolet light absorbing material as a raw material to form the ultraviolet light absorbing member UA, and various modes are possible. Moreover, it is good also as a structure which does not have the shade member 29 by providing the above ultraviolet light absorption members UA.

[Third Embodiment]
The virtual image display device according to the third embodiment will be described below. The virtual image display device according to the present embodiment is a modification of the virtual image display device 100 according to the first embodiment, and is the same as the first virtual image display device 100 unless otherwise described.

  A virtual image display device 100 illustrated in FIGS. 6A to 6C includes the image forming apparatus 10 and a light guide device 420 as a set. The light guide device 420 includes the light guide member 21, the angle conversion unit 423, and the light transmission member 23. Note that FIG. 6A corresponds to the AA cross section of the light guide device 420 illustrated in FIG.

  The overall appearance of the light guide member 21 is formed by a main body portion 20a which is a flat plate extending parallel to the XY plane in the drawing. Moreover, the light guide member 21 has the 1st reflective surface 21a, the 2nd reflective surface 21b, and the 3rd reflective surface 21c as a side surface. The light guide member 21 has an upper surface 21e and a lower surface 21f that are adjacent to the first, second, and third reflecting surfaces 21a, 21b, and 21c and that face each other. Furthermore, the light guide member 21 has a prism portion PS formed so as to expand the main body portion 20a at one end in the longitudinal direction and a third reflecting surface 21c associated therewith, and a plurality of mirrors at the other end in the longitudinal direction. It is the structure connected to the angle conversion part 423 comprised by these.

  The main body portion 20a is formed of a light-transmitting resin material or the like, and has a light incident surface IS that takes in image light from the image forming apparatus 10 on a back surface parallel to the XY plane and facing the image forming apparatus 10. doing. The main body portion 20a has a rectangular inclined surface RS in addition to the light incident surface IS as a side surface of the prism portion PS, and a mirror layer 25 is formed on the inclined surface RS so as to cover it. Here, the mirror layer 25 functions as the third reflecting surface 21c arranged in an inclined state with respect to the light incident surface IS by cooperating with the inclined surface RS. The third reflecting surface 21c folds the image light that is incident from the light incident surface IS and travels in the + Z direction as a whole so as to be directed in the −X direction that is biased in the −Z direction as a whole. Securely bond within 20a.

  The first and second reflecting surfaces 21a and 21b of the light guide member 21 are the main surfaces of the flat plate-like main body portion 20a and are bent by the prism portion PS as two planes facing each other and extending parallel to the XY plane. Each image light is totally reflected. The image light reflected by the third reflecting surface 21c first enters the first reflecting surface 21a and is totally reflected. Next, the image light enters the second reflecting surface 21b and is totally reflected. Hereinafter, by repeating this operation, the image light is guided to the back side of the light guide member 21, that is, the −X side where the angle conversion unit 423 is provided.

  As shown in FIG. 6C, in the light guide member 21, the third reflecting surface 21c and a light incident surface IS described later function as a light incident part B1. Further, the main body portion 20a sandwiched between the first and second reflecting surfaces 21a and 21b of the light guide member 21 and an angle conversion unit 423 described later function as the light guide unit B2. The angle conversion unit 423 functions as the light emission unit B3.

  The angle conversion part 423 is formed along the extended plane of the first and second reflecting surfaces 21a and 21b on the back side (−X side) of the light guide member 21. Here, the back end of the main body portion 20 a is a part of the angle conversion unit 423. The angle conversion unit 423 includes a large number of half mirror layers 28 that are inclined with respect to the first and second reflecting surfaces 21a and 21b and arranged in parallel to each other at equal intervals. The angle conversion unit 423 reflects the image light that has entered through the first and second reflecting surfaces 21a and 21b of the light guide member 421 at a predetermined angle, and passes through the light exit surface OS to the observer's eye EY side. Bend it. That is, the angle conversion unit 423 converts the angle of the image light.

  The light transmission member 23 is a portion obtained by extending the angle conversion portion 423 to the back side (−X side), and is a flat plate-like member like the main body portion 20 a of the light guide member 421.

  In the above, the whole angle conversion part 423 or a part on the entrance side also functions as a part of the light guide part B2 by being combined with the light guide member 21. Further, all or a part of the back side of the angle conversion unit 423 functions as a see-through part B4 when combined with the light transmission member 23.

  The image light emitted from the image forming apparatus 10 and incident on the light guide member 21 from the light incident surface IS is uniformly reflected and bent by the third reflection surface 21c, and the first and second reflection surfaces of the light guide member 21 are reflected. 21a and 21b are repeatedly totally reflected and proceed in a state of having a certain spread substantially along the optical axis AX. Further, the angle conversion unit 423 is bent at an appropriate angle so that it can be taken out. The light exits from the light exit surface OS attached to the conversion unit 423. The image light emitted to the outside from the light exit surface OS enters the observer's eye EY as virtual image light.

  Hereinafter, the optical path of the image light in the light guide device 420 will be described. In addition, the light guide apparatus 420 in 3rd Embodiment functions similarly to the light guide apparatus 20 of FIG. 1 (A) regarding the vertical 1st direction D1 (Y direction). On the other hand, the light guide device 420 guides a plurality of propagation mode image lights in the second horizontal direction D2 (X direction), and guides the two propagation mode image lights. This is different from the light guide device 20 in FIG.

  As shown in FIG. 6A, among the image light emitted from the liquid crystal display device (image light forming unit) 32 of the image display device 11, the component indicated by the dotted line emitted from the central portion of the emission surface 32a is an image. A component indicated by a one-dot chain line emitted from the right side (+ X side) of the emission surface 32a as the light GL41 is a component indicated by a two-dot chain line emitted from the left side (−X side) of the emission surface 32a as the image light GL42. Is image light GL43.

The main components of the image lights GL41, GL42, and GL43 that have passed through the projection optical system 12 are all incident at different angles on the first and second reflecting surfaces 21a and 21b after entering from the light incident surface IS of the light guide member 21, respectively. Repeat reflection. Specifically, among the image lights GL41, GL42, and GL43, the image light GL41 emitted from the central portion of the emission surface 32a of the liquid crystal display device (image light forming unit) 32 passes through the projection optical system 12 and then becomes a parallel beam. after being reflected by the incident third reflecting surface 21c on the light incident surface iS as, incident on the first reflecting surface 21a of the light guide member 21 with a standard reflection angle gamma _0, is totally reflected. Thereafter, the image light GL41 is, while maintaining the standard reflection angle gamma _0, the first and second reflecting surfaces 21a, repeating total reflection at 21b. The image light GL41 is totally reflected N times (N is a natural number) on the first and second reflection surfaces 21a and 21b, and reaches the central portion 23k of the angle conversion unit 423. The image light GL41 reflected by the central portion 23k is emitted as a parallel light flux in the optical axis AX direction perpendicular to the light emission surface OS or the XY plane from the light emission surface OS.

The image light GL42 emitted from one end side (+ X side) of the emission surface 32a of the liquid crystal display device 32 is incident on the light incident surface IS as a parallel beam after passing through the projection optical system 12, and is reflected by the third reflecting surface 21c. Thereafter, the light enters the first reflecting surface 21a of the light guide member 21 at the maximum reflection angle γ ₊ and is totally reflected. The image light GL42 is totally reflected, for example, NM times (M is a natural number) on the first and second reflecting surfaces 21a and 21b, and reaches the peripheral portion 23m on the most entrance side (+ X side) of the angle conversion portion 423. The image light GL42 reflected by the peripheral portion 23m forms an obtuse angle with respect to the + X axis so as to be away from the entrance third reflecting surface 21c side, and an angle θ ₁₂ (within the light guide device 420) with respect to the optical axis AX. Injected in a direction inclined by θ ₁₂ ′) (see FIG. 7).

The image light GL43 emitted from the other end side (−X side) of the emission surface 32a of the liquid crystal display device 32 is incident on the light incident surface IS as a parallel light flux after passing through the projection optical system 12, and is reflected by the third reflecting surface 21c. After that, the light enters the first reflecting surface 21a of the light guide member 21 at the minimum reflection angle γ ₋ and is totally reflected. The image light GL43 is totally reflected, for example, N + M times on the first and second reflecting surfaces 21a and 21b, and enters the peripheral portion 23h on the farthest side (−X side) of the angle conversion portion 423. The image light GL43 reflected by the peripheral portion 23h makes an acute angle with respect to the + X axis so as to be returned to the third reflecting surface 21c side, and has an angle θ ₁₃ (θ within the light guide device 420) with respect to the optical axis AX. It is injected in a direction inclined by ₁₃ ′) (see FIG. 7).

  As shown in FIG. 8, the angle conversion unit 423 has a structure in which a plurality of prisms 424 are arranged in the X direction at a predetermined pitch. Each prism 424 has a first joint surface 424j on the light exit side and a second joint surface 424c on the light incident side. On the first joint surface 21j of the main body portion 20a or the first joint surface 424j of each prism 424, a half mirror layer 28 that is a semi-transmissive reflective film is formed.

  Also in this embodiment, as in the case of the first and second embodiments, the surface side of the light guide device 20 is provided by providing the ultraviolet light absorbing member UA (see FIG. 3A, FIG. 5A, etc.). By covering the second reflection surface 21b side, the ultraviolet light component UV of the external light traveling toward the light guide device 20 can be absorbed in advance, and the influence of the ultraviolet light component on the light guide device 20 can be suppressed. The observer's eye EY is also protected from the ultraviolet light component UV. Thereby, for example, each light-transmitting optical member such as the half mirror layer 28 constituting the angle conversion unit 423 and the adhesive layer CC to which the angle mirror unit 423 is bonded can be protected.

[Fourth Embodiment]
The virtual image display device according to the fourth embodiment will be described below. The virtual image display device according to the present embodiment is a modification of the virtual image display device 100 according to the first embodiment, and is the same as the first virtual image display device 100 unless otherwise described.

  A virtual image display device 100 illustrated in FIGS. 9A to 9C includes the image forming device 10 and a light guide device 520 as a set. The light guide device 520 has a light guide member 521 as a part thereof. The light guide member 521 includes a main body portion 20a and an angle conversion unit 523 which is an image extraction unit. 9A corresponds to the AA cross section of the light guide member 521 shown in FIG. 9B.

  The overall appearance of the light guide member 521 is formed by a main body portion 20a which is a flat plate extending parallel to the XY plane in the drawing. Moreover, the light guide member 521 has the 1st reflective surface 21a, the 2nd reflective surface 21b, and the 3rd reflective surface 21c as a side surface. The light guide member 521 has an upper surface 21e and a lower surface 21f that are adjacent to the first, second, and third reflecting surfaces 21a, 21b, and 21c and that face each other. Furthermore, the light guide member 521 has a prism portion PS formed so as to expand the main body portion 20a at one end in the longitudinal direction and a third reflecting surface 21c associated therewith, and the main body portion 20a at the other end in the longitudinal direction. It has the structure which has the angle conversion part 523 comprised by many micromirrors embedded in. Although the light guide member 521 is an integral part, it can be divided into the light incident part B1, the light guide part B2, and the light emission part B3 as in the case of the first embodiment (FIG. 9 ( Among them, the light incident part B1 is a part having a third reflecting surface 21c and a light incident surface IS described later, and the light incident part B1 has first and second reflecting surfaces 21a, 21b. The light guide part B2 is a part having an angle conversion part 523 and a light exit surface OS described later.

  The main body portion 20a is formed of a light-transmitting resin material or the like, and light incident to capture image light from the image forming apparatus 10 on a back side or an observer side plane parallel to the XY plane and facing the image forming apparatus 10 It has a surface IS and a light emission surface OS that emits image light toward the eye EY of the observer. The main body portion 20a has a rectangular inclined surface RS in addition to the light incident surface IS as a side surface of the prism portion PS, and a mirror layer 25 is formed on the inclined surface RS so as to cover it. Here, the mirror layer 25 functions as the third reflection surface 21c which is an incident light bending portion arranged in an inclined state with respect to the light incident surface IS by cooperating with the inclined surface RS. The third reflecting surface 21c folds the image light that is incident from the light incident surface IS and travels in the + Z direction as a whole so that the image light is directed in the −XZ direction that is biased in the −Z direction as a whole. Securely bond within 20a. Further, in the main body portion 20a, an angle conversion portion 523 having a fine structure is formed along the plane on the back side of the light emission surface OS. The main body portion 20a extends from the third reflection surface 21c on the entrance side to the angle conversion unit 523 on the back side, and guides the image light incident inside through the prism unit PS to the angle conversion unit 523.

  The first and second reflecting surfaces 21a and 21b of the light guide member 521 are the main surfaces of the flat plate-like main body portion 20a and are two planes facing each other and extending in parallel to the XY plane. Each of the image lights bent at B1 is totally reflected. The image light reflected by the third reflecting surface 21c first enters the first reflecting surface 21a and is totally reflected. Next, the image light enters the second reflecting surface 21b and is totally reflected. Hereinafter, by repeating this operation, the image light is guided to the back side of the light guide device 520, that is, the −X side where the angle conversion unit 523 is provided.

  The angle conversion unit 523 arranged to face the light emission surface OS of the main body portion 20a is on the extended plane along the extended plane of the second reflecting surface 21b on the back side (−X side) of the light guide member 521. It is formed in close proximity. The angle conversion unit 523 reflects the image light incident through the first and second reflection surfaces 21a and 21b of the light guide member 521 at a predetermined angle and bends the light toward the light exit surface OS. That is, the angle conversion unit 523 converts the angle of the image light.

  The image light emitted from the image forming apparatus 10 and incident on the light guide member 521 from the light incident surface IS is uniformly reflected and bent by the third reflection surface 21c, and the first and second reflection surfaces of the light guide member 521 are bent. 21a and 21b are repeatedly totally reflected and proceed in a state of having a certain spread substantially along the optical axis AX. Further, the angle conversion unit 523 is bent at an appropriate angle so that it can be taken out. Injected outside from the exit surface OS. The image light emitted to the outside from the light exit surface OS enters the observer's eye EY as virtual image light. By forming the virtual image light on the retina of the observer, the observer can recognize image light such as video light by the virtual image.

  Hereinafter, the optical path of the image light in the light guide device 520 will be described. In addition, the light guide device 520 in the fourth embodiment functions in the same manner as the light guide device 20 in FIG. 1A with respect to the vertical first direction D1 (Y direction). On the other hand, the light guide device 520 guides a large number of propagation mode image lights in the second horizontal direction D2 (X direction), and guides the two propagation mode image lights. This is different from the light guide device 20 in FIG.

  As shown in FIG. 9A, among the image light emitted from the liquid crystal display device (image light forming unit) 32 of the image display device 11, the component indicated by the dotted line emitted from the central portion of the emission surface 32a is an image. A component indicated by a one-dot chain line emitted from the right side (+ X side) of the emission surface 32a as the light GL51 is defined as an image light GL52, and a component indicated by a two-dot chain line emitted from the left side (−X side) of the emission surface 32a. Is image light GL53.

The main components of the image lights GL51, GL52, and GL53 that have passed through the projection optical system 12 are all incident at different angles on the first and second reflecting surfaces 21a and 21b after entering from the light incident surface IS of the light guide member 521, respectively. Repeat reflection. Specifically, among the image lights GL51, GL52, and GL53, the image light GL51 emitted from the central portion of the emission surface 32a of the liquid crystal display device (image light forming unit) 32 passes through the projection optical system 12 and then becomes a parallel beam. After being incident on the light incident surface IS and reflected by the third reflecting surface 21c, the light is incident on the first reflecting surface 21a of the light guide member 521 at the standard reflection angle γ ₀ and totally reflected. Thereafter, the image light GL51 is, while maintaining the standard reflection angle gamma _0, the first and second reflecting surfaces 21a, repeating total reflection at 21b. The image light GL51 is totally reflected N times (N is a natural number) on the first and second reflection surfaces 21a and 21b, and reaches the central portion 23k of the angle conversion unit 523. The image light GL51 reflected by the central portion 23k is emitted from the light exit surface OS as a parallel light flux in the optical axis AX direction perpendicular to the light exit surface OS or the XY plane.

The image light GL52 emitted from one end side (+ X side) of the emission surface 32a of the liquid crystal display device 32 enters the light incident surface IS as a parallel light flux after passing through the projection optical system 12, and is reflected by the third reflecting surface 21c. Thereafter, the light enters the first reflection surface 21a of the light guide member 521 at the minimum reflection angle γ ₊ and is totally reflected. The image light GL52 is totally reflected, for example, NM times (M is a natural number) on the first and second reflection surfaces 21a and 21b, and reaches the peripheral portion 23h on the farthest side (−X side) of the angle conversion portion 523. . The image light GL52 reflected by the peripheral portion 23h forms an acute angle with respect to the + X axis so as to return to the third reflecting surface 21c side of the entrance, and an angle θ ₁₂ (within the light guide device 520 with respect to the optical axis AX). Then, it is ejected in a direction inclined by θ ₁₂ ′) (see FIG. 10).

The image light GL53 emitted from the other end side (−X side) of the emission surface 32a of the liquid crystal display device 32 enters the light incident surface IS as a parallel light flux after passing through the projection optical system 12, and is reflected by the third reflecting surface 21c. After that, the light enters the first reflecting surface 21a of the light guide member 521 at the minimum reflection angle γ ₋ and is totally reflected. The image light GL53 is totally reflected, for example, N + M times on the first and second reflecting surfaces 21a and 21b, and enters the peripheral portion 23m on the most entrance side (+ X side) of the angle conversion unit 523. Image light GL53 was a reflection at the peripheral portion 23m, a third obtuse angle with respect to As + X-axis away from the reflecting surface 21c side, the angle theta ₁₃ (light guide device within 520 with respect to the optical axis AX theta ₁₃ Injected in a direction inclined by ') (see FIG. 10).

  As shown in FIG. 10, the angle conversion unit 523 includes a large number of linear reflection units 2c arranged in a stripe shape. In other words, the angle conversion unit 523 is configured by arranging a number of elongated reflection units 2c extending in the Y direction along the main light direction, that is, the −X direction, in which the angle conversion unit 523 extends at a predetermined pitch PT. Each reflection unit 2c is a first reflection surface 2a that is one reflection surface portion disposed on the back side, that is, the optical path downstream side, and another one reflection surface portion that is disposed on the entrance side, that is, the optical path upstream side. The second reflecting surface 2b is provided as a set, and both reflecting surfaces 2a and 2b form a constant wedge angle δ. Among these, at least the second reflecting surface 2b is a partially reflecting surface that can transmit a part of light, and allows an observer to observe an external image in a see-through manner. In the reflection unit 2c, the image lights GL52 and 53 are first reflected by the first reflection surface 2a on the back side, that is, the −X side, and then reflected by the second reflection surface 2b on the entrance side, that is, the + X side. The The image light GLs 52 and 53 that have passed through the reflection unit 2c are bent to a desired angle and taken out to the viewer side by passing through the angle conversion unit 523 only once without passing through the other reflection unit 2c.

  As shown in FIG. 11, the angle conversion unit 523 has a structure in which a relatively thick plate-like joining member 521 n extending from the light guide member 521 and a relatively thin plate-like joining member 523 n extending from the light transmitting member 23 are joined. Have A half mirror layer 28 is formed on the first bonding surface 21j of the bonding member 521n.

  As another example, as shown in FIG. 12, the angle conversion unit 623 is provided with a concavo-convex part 621 n having a fine structure for forming the reflection unit 2 c on a part of the light guide member 621, and After the half mirror layer 28 is formed, the half mirror layer 28 may be formed by filling the uneven portion 621n with the resin material 623n. In this case, as the resin material 623n, for example, an ultraviolet curable material is used, and the uneven portion 621n having a fine structure is filled with no gap, and then cured by ultraviolet irradiation to produce the angle conversion unit 623. be able to. That is, the angle conversion part 623 can be comprised with an ultraviolet curing member. The angle conversion unit 623 made of an ultraviolet curing member is protected from the ultraviolet light component UV included in the external light GL ′ by the ultraviolet light absorbing member UA (see FIG. 3A and the like).

  Also in this embodiment, as in the case of the first and second embodiments, the surface side of the light guide device 20 is provided by providing the ultraviolet light absorbing member UA (see FIG. 3A, FIG. 5A, etc.). By covering the second reflection surface 21b side, the ultraviolet light component UV of the external light traveling toward the light guide device 20 can be absorbed in advance, and the influence of the ultraviolet light component on the light guide device 20 can be suppressed. The observer's eye EY is also protected from the ultraviolet light component UV. Thereby, for example, it is possible to protect the light transmissive optical members such as the half mirror layer 28 constituting the angle conversion units 523 and 623 and the adhesive layer CC to which the angle mirrors are bonded.

[Others]
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.

  In the above description, the light guide device 20 has the hard coat layer 27, but may not have the hard coat layer 27. Further, although the shade member 29 is detachable, it may be fixed so that the shade member 29 is always attached. For example, when the shade member 29 is fixed, it is conceivable that the hard coat layer 27 is not provided on at least the shade member 29 side of the light guide device 20.

  In the above embodiment, the half mirror layer 28 that is a transflective portion is a transflective film formed by depositing a metal reflective film or a dielectric multilayer film made of silver or the like, but is not limited thereto. The transflective portion may be configured by a transflective member having transflective properties, a translucent sheet, or the like. Further, for example, as shown in FIG. 13A, a third reflecting surface 21c and a fourth reflecting surface are replaced by hologram elements HE1 and HE2 instead of the mirror layer 25 and the half mirror layer 28 (see FIG. 2A). 21d may be formed. That is, the transflective portion that bends the image light and transmits the external light may be configured by the hologram element HE2. In this case, the image display device 11 has, for example, an LED light source that generates light beams of three colors as a light source, and the hologram elements HE1 and HE2 have a hologram layer having a three-layer structure corresponding to the three colors. . Accordingly, the hologram elements HE1 and HE2 have a function of reflecting each color light from the image display device 11 in a desired direction as virtual mirrors formed in the vicinity of the third reflecting surface 21c and the fourth reflecting surface 21d. It will have. That is, the hologram elements HE1 and HE2 can adjust the reflection direction of the image light. Further, when the hologram elements HE1 and HE2 are used, each color light can be reflected in a desired direction. Therefore, for example, as shown in FIG. 13B, the first and second reflecting surfaces 21a are formed by extending the second reflecting surface 21b without inclining the third and fourth reflecting surfaces 21c and 21d with respect to the first reflecting surface 21a. The hologram elements HE1 and HE2 may be formed on a plane parallel to. In addition, since the hologram element HE2 acts only on light in a specific wavelength band and transmits light in other wavelength bands, see-through observation is possible by allowing external light to pass through.

  In the above description, the light guide device 20 including the light incident part B1, the light guide part B2, and the light emitting part B3 is used. However, in the light incident part B1 and the light emitting part B3, it is not necessary to use a plane mirror. A lens-like function can be provided by a spherical or aspherical curved mirror. Furthermore, as shown in FIG. 14, a prism or block-shaped relay member 1125 separated from the light guide B <b> 2 can be used as the light incident part B <b> 1. It can also have a special function. In addition, although the light guide 26 which comprises the light guide part B2 is provided with the 1st and 2nd reflective surfaces 21a and 21b which are the 1st and 2nd surfaces which propagate image light GL by reflection, These reflecting surfaces 21a and 21b do not need to be parallel to each other, and may be curved surfaces.

  In the above description, the transmissive liquid crystal display device 32 or the like is used as the image light forming unit. However, the image light forming unit is not limited to the transmissive liquid crystal display device, and various types 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, a self-luminous display device such as an organic EL can be used in place of the liquid crystal display device 32.

  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. As a result, the liquid crystal display device 32 can be efficiently illuminated, and luminance unevenness due to the position of the image light GL can be reduced.

  In the above description, the light incident surface IS and the light exit surface OS are arranged on the same plane. However, the present invention is not limited to this. For example, the light incident surface IS is on the same plane as the first reflecting surface 21a. The light emission surface OS may be arranged on the same plane as the second reflection surface 21b. In this case, the first reflecting surface 21a and the fourth reflecting surface 21d form an obtuse angle.

  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 panel 110 of FIG. 1, that is, the light guide members 21, 421, and 521 are arranged in parallel, not in series.

  In the above description, the light guide device 20 including the light incident part B1, the light guide part B2, and the light emitting part B3 is used. However, in the light incident part B1 and the light emitting part B3, it is not necessary to use a plane mirror. A lens-like function can be provided by a spherical or aspherical curved mirror. Furthermore, a prism or a block-like relay member separated from the light guide B2 can be used as the light incident part B1, and the incident and exit surfaces and the reflective inner surface of the relay member can also have a lens function.

  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 virtual image display device 100 according to the above-described embodiment, the display devices 100A and 100B (specifically, the image forming device 10, the light guide device 20, and the like) are provided for each of the right eye and the left eye. However, for example, the image forming apparatus 10 and the light guide device 20 may be provided only for either the right eye or the left eye so that the image is viewed with one eye.

  In addition, a lens or other optical element can be disposed so as to face the light exit surface OS of the light guide member 21 shown in FIG. Alternatively, the half mirror layer 28 can be replaced with a hologram sheet covered with a protective layer. In this case, a highly coherent one is used as the illuminating device 31, and a laminated diffraction sheet for individually processing, for example, three color images formed by the liquid crystal display device 32 is used as the hologram sheet.

  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 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. .

  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.

  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.

  2c ... reflection unit 10 ... image forming device 11 ... image display device 12 ... projection optical system 20, 420, 520 ... light guide device, 20a ... main body part 21, 421, 521 ... light guide member, 21a, 21b, 21c, 21d ... 1st-4th reflective surface, 23 ... Light transmission member, 23s ... Main part, 23a ... 1st surface, 23b ... 2nd surface, 25 ... Mirror layer, 27 ... Hard coat layer (UV curing) Member), 28 ... half mirror layer (semi-transmissive reflective film), 31 ... illumination device, 29 ... shade member, 32 ... liquid crystal display device, 34 ... drive control unit, 100 ... virtual image display device, 100A, 100B ... display device, DESCRIPTION OF SYMBOLS 110 ... Optical panel, 423, 523, 623 ... Angle conversion part, 424 ... Prism, UA ... Ultraviolet light absorption member, AX, AX1, AX2 ... Optical axis, B1 ... Incident part, B2 ... light guide part, B3 ... light emitting part, B4 ... transparent part, CC ... adhesive layer, EY ... eye, GL ... image light, GL '... external light, GL1, GL2 ... image light, IM1, IM2 ... Projected image (virtual image), IS ... light incident surface, OS ... light exit surface, SL ... illumination light, UV ... ultraviolet light component, VR ... visible light component

Claims (15)

An image display device for forming image light;
A projection optical system for forming a virtual image by the image light emitted from the image display device;
A light incident part that takes in the image light that has passed through the projection optical system, a light guide part that guides the image light taken from the light incident part, and the image light that has passed through the light guide part is taken out to the outside. A light guide unit having a light emitting part;
With
An ultraviolet light absorbing material that is disposed so as to cover the surface of the light guide device and absorbs a component of ultraviolet light contained in light directed from the outside toward the light guide device;
The light guide device has a hard coat layer provided along with a light guide surface that contributes to the light guide of the image light,
The said ultraviolet light absorber is a virtual image display apparatus arrange | positioned so that the said hard-coat layer of the external field side may be covered at least among the said light guide surfaces. The light guide portion includes first and second total reflection surfaces that extend opposite to each other and guide the image light by total reflection;
The virtual image display device according to claim 1, wherein the hard coat layer is provided on at least the first and second total reflection surfaces.   The light emitting unit includes a transflective film that reflects the image light that has passed through the light guide unit and extracts the image light to the outside, and allows the external light to pass through and allows observation of the external light. Item 3. The virtual image display device according to any one of Items 2 to 3. The virtual image display device according to claim 2 , further comprising a shade member that covers the light guide device from outside and adjusts an amount of incident external light that is incident and that includes the ultraviolet light absorber.   The virtual image display device according to claim 4, wherein the shade member is detachable and is disposed with a space provided on a surface of the light guide device.   The virtual image display device according to claim 5, wherein the shade member has a positioning portion for providing a surface and a space of the light guide device. The said shade member has an area larger than the area of the said 2nd total reflection surface provided in the external field side, and covers the said light guide device, The any one of Claim 4-6 characterized by the above-mentioned. Virtual image display device. The light guide device has an upper surface and a lower surface adjacent to the first and second total reflection surfaces,
The virtual image display device according to any one of claims 4 to 6, wherein the shade member covers the light guide device from the outside and covers the upper surface and the lower surface. The said ultraviolet light absorber is the said shade member formed with the material which mixed the ultraviolet light absorptive material or the said ultraviolet light absorptive material, It is any one of Claim 4-8. The virtual image display device described. The virtual image display device according to any one of claims 4 to 9, wherein the ultraviolet light absorbing material is a detachable film-like member or a laminated film provided on a surface of the shade member. The light guide device includes a UV curable member which is cured by absorbing ultraviolet light, the virtual image display device according to any one of claims 1 to 10. The ultraviolet light absorbers, of the light passing through the substantially transmits at a certain transmittance to visible light belonging to a long wavelength band than ultraviolet light, according to any one of claims 1 to 11 Virtual image display device. The ultraviolet light absorbing material, wherein the transmittance of a predetermined wavelength band among the wavelength band of ultraviolet light, is smaller than the transmittance of light in the visible light wavelength region bands, the virtual image according to claim 12 Display device. The light guide device constitutes a light guide member including the light incident part, the light guide part, and the light emitting part, and a see-through part that enables observation of external light by joining the light guide member. A virtual image display device according to any one of claims 1 to 13, further comprising: a light transmission member whose outside is covered with the ultraviolet light absorbing material. 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;
15. The virtual image display device according to claim 1, wherein the light emitting unit includes a fourth reflecting surface that forms a predetermined angle with respect to the first reflecting surface.

Images