JP2013080039A - Virtual image display device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a virtual image display device including a light guide device protected by a hard coat layer which has air bubbles hardly formed in a joining part with a prism-like member and has excellent adhesion, and a method for manufacturing the same.SOLUTION: Roughening of at least a part of a coated ground surface SF in a light guide member 21 hardly generates liquid dripping of an adhesive even by, for example, lowering viscosity of the adhesive for coating the ground surface SF to prevent air bubbles from being generated when the light guide member 21 is joined to a light transmissive member 23. According to a virtual image display device 100, roughening of at least a part of the coated ground surface SF in the light guide member 21 allows adhesion of a hard coat layer 27 to be secured regardless of a material of a ground body part 21s, for example, when there is formed the hard coat layer 27 for forming an appearance exposed surface such as a first and second reflective surfaces 21a and 21b and coating the ground surface SF.

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, and a method for manufacturing the same.

  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 in order to superimpose image light and external light (see Patent Document 1, etc.).

  However, in the apparatus described in Patent Document 1, since see-through is realized by a pupil division method using a light guide optical system having an exit aperture smaller than the pupil size, 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.

  In addition, there is an optical system for a head-mounted display that includes a light guide that can advance a plurality of light modes having different light guide angles (see Patent Document 2). In such an optical system, the third optical surface on the emission side is a half mirror, and a prism-like member is attached to the light guide so as to embed the half mirror inside, thereby flattening the whole. It is conceivable to use a see-through type light guide device that enables observation of external light through a half mirror. Furthermore, the light guide and the main body of the prism-like member are formed of a lightweight resin to reduce the weight of the virtual image display device, and the surface of the light guide is covered with a hard coat layer. It is also conceivable to improve the scratch resistance of the surface of the prism-like member.

  However, when the light guide and the prism-like member are joined, bubbles are generated due to uneven application of the adhesive. For example, when the viscosity of the adhesive is high, the escape route of bubbles disappears and the bubbles remain at the joint, and when the viscosity of the adhesive is low, an insufficient amount of coating occurs due to liquid dripping of the adhesive, causing bubbles to be formed.

  Moreover, when providing a hard-coat layer on the surface of a light guide or a prism-shaped member, it is necessary to ensure the adhesiveness of this hard-coat layer and the lower surface of a main-body part.

JP 2010-224473 A Special table 2008-535001 gazette

  The present invention is a light guide device that guides image light of a virtual image, and a virtual image display device in which bubbles are hardly formed at a joint portion with a prism-like member and a manufacturing method thereof, or a hard coat layer having good adhesion It is an object of the present invention to provide a virtual image display device including a protected light guide device and a manufacturing method thereof.

  In order to achieve the above object, a virtual image display device according to the present invention includes (a) an image display device that forms image light, and (b) a projection optical system that forms a virtual image by image light emitted from the image display device. (C) A light incident part that takes in the image light that has passed through the projection optical system, and a light guide that guides the image light taken from the light incident part by total reflection at the first and second reflection surfaces that extend opposite to each other. And a light emitting member that takes out image light that has passed through the light guide portion to the outside, and (d) at least a portion of the ground surface covered with the light guide member is rough It is faced.

  In the virtual image display device, since at least a part of the ground surface covered with the light guide member is roughened, for example, when the light guide member and another optical member are joined, the ground surface is covered. Even if the viscosity of the adhesive is lowered to make it difficult for bubbles to be generated, dripping of the adhesive is less likely to occur. Further, in the virtual image display device, since at least a part of the base surface covered with the light guide member is roughened, for example, an external appearance exposed surface such as the first and second reflecting surfaces is formed to form the base surface. When forming the hard coat layer covering the film, the adhesion of the hard coat layer can be ensured regardless of the material of the base body portion.

  In a specific aspect of the present invention, a light transmission member that enables observation of external light by being bonded to the light guide member is further provided, and the light guide member and the light transmission member are bonded as a base surface covered with the light transmission member. At least a part of the surface is roughened. In this case, it is possible to provide a see-through unit that allows easy observation of external light by joining the light guide member and the light transmitting member.

  In another aspect of the present invention, the base surface that is in contact with the hard coat layer exposed in the light guide member and the light transmission member and the adhesive layer between the light guide member and the light transmission member is roughened. Thereby, the adhesiveness of the hard-coat layer in a light guide member and a light transmissive member can be improved, and it can prevent that a bubble remains in the junction part of a light guide member and a light transmissive member.

  In still another aspect of the present invention, the light guide member has a transflective film that folds the image light and transmits the external light on the partial region of the first joint surface joined to the light transmissive member, The transmission member has a second bonding surface that is bonded to the first bonding surface via the bonding layer, and the bonding layer disposed between at least one of the first bonding surface and the second bonding surface. The contacting portion is roughened as a base surface. In this case, the light guide member and the light transmissive member are bonded around the semi-transmissive reflective film via the adhesive layer, but bubbles are less likely to remain in the bonding adhesive layer.

  In yet another aspect of the present invention, the light incident portion has a third reflection surface that forms a predetermined angle with respect to the first reflection surface, and the light emission portion has a predetermined angle with respect to the first reflection surface. A fourth reflecting surface formed, a first joining surface in contact with the adhesive layer, and a light transmitting member extending a first transmitting surface disposed at a position extending from the first reflecting surface; and a second reflecting surface extending A second transmission surface disposed at the position and a second bonding surface facing the first bonding surface with an adhesive layer interposed therebetween, and a transflective film is formed on the fourth reflection surface, and the second bonding surface Is roughened. In this case, 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 a virtual image. As incident on the eyes of the observer. Here, by making the light incident portion, the light guide portion, and the light emitting portion into an integral block-like member, the light guide device can be formed with high accuracy by using an injection molding technique. Also, by roughening the second joint surface of the first and second joint surfaces and joining the light guide member and the light transmission member, bubbles are formed at the joint between the light guide member and the light transmission member. Can be suppressed.

  In still another aspect of the present invention, the main body side in contact with the hard coat layer formed on the first and second reflection surfaces and the first and second transmission surfaces is roughened as a base surface. The first and second reflecting surfaces and the first and second transmitting surfaces have improved scratch resistance due to the overcoat layer provided on them.

  In still another aspect of the present invention, the main body part constituting the light guide member is formed of an ultraviolet curable resin and has a ground surface roughened at least partially. In this case, there is no need to process at a high temperature as in the case where the main body portion constituting the light guide member is formed of a thermoplastic resin, and the shape accuracy of the light guide member can be increased.

  In still another aspect of the present invention, the light guide member, the light transmission member, the hard coat layer, and the adhesive layer are formed of a material having the same refractive index. In this case, it is possible to suppress the disturbance of the light flux on the first and second reflecting surfaces of the light guide member and to accurately observe the external light.

  In still another aspect of the present invention, the main body portion of the light guide member and the main body portion of the light transmitting member are formed of methacryl styrene. In this case, high-precision injection molding of the light guide member is facilitated, water absorption of the light guide member can be kept low, adhesiveness with sufficient strength with the light transmissive member can be ensured, and the light guide member The transparency of can be increased.

  In still another aspect of the invention, the surface roughness of at least a part of the base surface is larger than the surface roughness of the first and second reflecting surfaces.

  A method of manufacturing a virtual image display device according to the present invention includes an image display device that forms image light, a projection optical system that forms a virtual image by image light emitted from the image display device, and image light that has passed through the projection optical system. A light incident part that takes in the light, a light guide part that guides image light taken from the light incident part by total reflection at the first and second reflecting surfaces that extend opposite to each other, and image light that has passed through the light guide part to the outside A light-emitting member including a light guide member and a virtual image display device comprising: a first step of roughening at least a part of a lower ground of the light guide member; And a second step of covering the underlying surface.

  The manufacturing method includes the first step of roughening at least a part of the lower ground of the light guide member and the second step of covering the roughened base surface. When bonding the adhesive to another optical member, even if the viscosity of the adhesive covering the base surface is lowered to make it difficult for bubbles to be generated, dripping of the adhesive is less likely to occur. For example, the first and second reflecting surfaces When forming a hard coat layer that covers a base surface on which an external appearance exposed surface is formed, the adhesion of the hard coat layer can be ensured regardless of the material of the base body portion.

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) explains the structure of the 1st and 2nd reflective surface in the light guide part of a light guide member. (C) is a figure explaining the structure of the junction part of a light guide member and a light transmissive member, (D) is a figure explaining the structure of the 1st and 2nd surface of a light transmissive member. It is. (A) is a front view of the light guide member, (B) is a bottom view of the light guide member, (C) is a left side view of the light guide member, and (D) is a left side view of the light guide member. FIG. (A) is a rear view of the light transmitting member, (B) is a BB cross-sectional view of the light transmitting member, (C) is a left side view of the light transmitting member, and (D) is a right side of the light transmitting member. FIG. It is an expanded sectional view which illustrates notionally the junction part of a light guide member and a light transmission member. It is an expanded sectional view explaining the hard-coat layer of a light guide member. It is an expanded sectional view explaining the hard-coat layer of a light transmissive member. (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) And (B) is a figure explaining a part of virtual image display device of a modification. It is an expanded sectional view which explains the light guide device of a 2nd embodiment notionally. (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 a figure explaining the modification of the virtual image display apparatus of 3rd Embodiment. It is a figure explaining the modification of the virtual image display apparatus of 1st Embodiment.

[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)
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 is added to an optical panel 110 that covers the eyes of the observer, a frame 121 that supports the optical panel 110, and a portion of the frame 121 that extends from a front cover portion to a rear vine portion (temple). First and second driving units 131 and 132 are provided. 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. 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 illumination device 31 of the image display device 11 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. Have 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.

  In the image display device 11 or the liquid crystal display device 32 described above, the first direction D1 corresponds to the vertical Y direction, and the second direction D2 corresponds to the horizontal X direction. The first direction D1 and the second direction D2 are orthogonal to the first optical axis AX1 passing through the projection optical system 12, and are orthogonal to each other.

  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 includes a light guide member 21 and a light transmission member 23. The light guide member 21 is joined and fixed so as to be fitted into the frame-like light transmission member 23, and constitutes a flat plate-like optical member extending in parallel to the XY plane as a whole.

  Of the light guide device 20, the light guide member 21 is a trapezoidal prism-like member in plan view, and includes a first reflecting surface 21 a, a second reflecting surface 21 b, a third reflecting surface 21 c, and a first surface as side surfaces. And a joining surface 21j. The light guide member 21 includes a first side surface 21e and a second side surface 21f that are adjacent to the first, second, and third reflecting surfaces 21a, 21b, and 21c and the first joint surface 21j 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 with an acute angle α of 45 ° or less with respect to the XY plane, and the first joint surface 21j is inclined with an acute angle β of 45 ° or less with respect to the XY surface, for example. . In other words, the third reflecting surface 21c has an obtuse angle η with respect to the second reflecting surface 21b, and the first joint surface 21j has an obtuse angle ε with respect to the second reflecting surface 21b. The first optical axis AX1 passing through the third reflecting surface 21c and the second optical axis AX2 passing through the first joining surface 21j 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 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 folded back by a plurality of reflections during light guide, that is, the confinement direction DW2, is perpendicular to the first and second reflecting surfaces 21a and 21b (parallel to the Z axis). ) Corresponds to the second direction D2 of the liquid crystal display device 32 when the optical path is expanded to the light source side as will be described later. On the other hand, the longitudinal direction, that is, the non-confining direction DW1 that propagates without being folded back by reflection during light guide is parallel to the first and second reflecting surfaces 21a, 21b and the third reflecting surface 21c (parallel to the Y axis), which will be described later. Thus, when the optical path is developed to the light source side, it corresponds to the first direction D1 of the liquid crystal display device 32. In the light guide member 21, the main light direction in which the propagated light beam travels as a whole is the -X direction.

  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 has a block-shaped member integrally molded by injection molding as a main body portion 21s, and the main body portion (block-shaped member) 21s is made of, for example, a heat or photopolymerization type resin material in a molding die. It is formed by injecting and thermosetting or photocuring. In a specific example, the light guide member 21 is formed of an ultraviolet curable resin. As described above, the light guide member 21 has the main body portion 21s as an integrally formed product, but can be functionally 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 is a reflecting 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 substantially the entire rectangular area. A mirror layer 25 is provided. The mirror layer 25 is formed by forming a film on the slope RS of the light guide member 21 by vapor deposition of aluminum or the like.

  FIG. 3A is a conceptual diagram in which the cross section of the surface portion SP1 in the light incident portion B1 is partially enlarged in order to explain the structure of the third reflecting surface 21c. 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 Al (aluminum) or the like on the slope RS of the main body portion 21 s constituting the light guide member 21.

  2A and the like, the third reflecting surface 21c is inclined at an acute angle α = 25 ° to 27 °, for example, with respect to the first optical axis AX1 or the XY plane of the projection optical system 12, and the light incident The image light GL that enters from the surface IS and travels in the + Z direction as a whole is bent so as to travel 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 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 surface portion of the first reflecting surface 21a is common to the light incident surface IS and a light exit surface OS described later. The first and second reflection surfaces 21a and 21b are total reflection surfaces using a difference in refractive index, and the surface is not provided with a non-transmissive reflection coat such as a mirror layer.

  3B partially enlarges the cross section of the surface portions SP2 and SP3 in the light guide portion B2 of the light guide member 21 in order to explain the structure of the first reflective surface 21a and the structure of the second reflective surface 21b. FIG. The first and second reflecting surfaces 21a and 21b are formed by covering with a hard coat layer 27 in order to prevent damage to the surface and to prevent a reduction in image resolution. The hard coat layer 27 is formed by forming a coating agent made of a resin or the like on the lower ground SF of the main body portion 21s of the light guide member 21 by dipping or spray coating.

  Returning to FIG. 2A and the like, the image light GL reflected by the third reflecting surface 21c of the light incident portion B1 first enters the first reflecting surface 21a of the light guide portion B2 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 leading light direction on the back side of the light guide device 20 as a whole, that is, to the −X side provided with the light emitting part B3. Since the first and second reflecting surfaces 21a and 21b are not provided with a non-transmissive or semi-transmissive reflective coating, the external light or the external light incident on the second reflective surface 21b from the outside is high. It passes through the light guide B2 with transmittance. 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 first bonding surface 21j 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 first joint surface 21j is a substantially rectangular inclined surface (inclined surface RS), and reflects the image light GL incident thereon via the first and second reflecting surfaces 21a and 21b to emit light. It has the 4th reflective surface 21d for making it inject | emitted out of B3.

  The fourth reflecting surface 21 d has a half mirror layer 28. The half mirror layer 28 is a light-transmissive reflective film (that is, a semi-transmissive reflective film). The half mirror layer (semi-transmissive reflective film) 28 is formed not on the entire first bonding surface 21j but on the partial area PA0. That is, the fourth reflecting surface 21d is formed on the partial region PA0 corresponding to a part of the first bonding surface 21j. Of the first joint surface 21j, the partial region PA0 where the half mirror layer 28 is to be formed is disposed on the center side in the non-confinement direction DW1 that is the vertical direction, and a pair of peripheral regions PA1, It is sandwiched between PA2. The remaining area (other area) PA obtained by combining these peripheral areas PA1 and PA2 is an area where the half mirror layer 28 as the fourth reflecting surface 21d does not exist, and transmits the image light GL or the like almost as it is. The half mirror layer 28 is formed by forming a metal reflective film or a dielectric multilayer film on the partial area PA0 of the first joint surface 21j that is one side surface of the main body portion 21s constituting 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.

  FIG. 3C is a conceptual diagram in which the cross section of the joint portion SP4 is partially enlarged in order to explain the structure of the fourth reflecting surface 21d and the like. Here, a light guide is provided between the fourth reflecting surface 21d of the light guide member 21 and the second joint surface 23c of the light transmission member 23, more precisely between the half mirror layer 28 and the second joint surface 23c. The adhesive layer CC is formed by an adhesive for joining the member 21 and the light transmitting member 23. That is, the second joint surface 23c of the light transmitting member 23 is covered with the adhesive layer CC, and is a base surface covered with the joint portion SP4. The adhesive layer CC has a refractive index substantially equal to that of the main body portion 21 s of the light guide member 21 and the main body portion 23 s of the light transmission member 23, and these and the adhesive layer CC extend from the light guide member 21 to the light transmission member 23. Light passing through the interface is prevented from unnecessary reflection at the interface.

  Returning to FIG. 2A and the like, the fourth reflecting surface 21d or the first bonding surface 21j is, for example, an acute angle α = 25 ° to 27 with respect to the second optical axis AX2 or XY plane perpendicular to the first reflecting surface 21a. The image light GL incident through the first and second reflecting surfaces 21a and 21b of the light guide B2 is partially reflected by the half mirror layer 28 in the −Z direction as a whole. The light exit surface OS is allowed to pass by being bent so as to face. The component of the image light transmitted through the fourth reflecting surface 21d is incident on the light transmitting member 23 and is not used for forming an image.

  As shown in FIG. 2B, the effective region EA through which the image light GL passes in the light guide member 21 is relatively vertically long on the light incident part B1 side, and is relatively horizontally long on the light emitting part B3 side. It has become. The fourth reflecting surface 21d or the half mirror layer 28 is a part of the first joint surface 21j, and is formed so as to cover the effective area EA of the image light GL. The image light GL guided to the light passes through the light incident part B1 without waste and enters the eye EY of the observer. As described above, the half mirror layer 28 has a horizontally long outline, but corresponds to the horizontally long outline of the image forming area AD of the liquid crystal display device 32.

  The light transmissive member 23 is made of a resin material that exhibits high light transmittance in the visible region and has substantially the same refractive index as the main body portion 21 s of the light guide member 21. The light transmitting member 23 has a block-like member integrally molded by injection molding as the main body portion 23s. The main body portion (block-shaped member) 23s is formed by, for example, injecting a heat or photopolymerization type resin material into a molding die and thermosetting or photocuring the same as the light guide member 21.

  The light transmitting member 23 is a see-through optical part adjacent to the light emitting part B3 of the light guide member 21, and has a first surface 23a, a second surface 23b, and a second bonding surface 23c. The first and second surfaces 23a and 23b extend along the XY plane. The second bonding surface 23c is inclined with respect to the XY plane, and is disposed in parallel to face the first bonding surface 21j or the fourth reflecting surface 21d of the light guide member 21. That is, the light transmission member 23 has a wedge-shaped member WP sandwiched between the second surface 23b and the second bonding surface 23c. The light transmission member 23 includes an upper support member 24b and a lower support member 24c, which will be described later, as support portions that extend from the wedge-shaped member WP and support the light guide member 21 from above and below.

  In the light transmissive member 23, the first surface 23 a is a first transmissive surface disposed on an extended plane of the first reflective surface 21 a provided on the light guide member 21, and is on the back side near the observer's eye EY, The second surface 23b is a second transmission surface arranged on an extended plane of the second reflection surface 21b provided on the light guide member 21, and is on the front side far from the eye EY of the observer. The second bonding surface 23c is a rectangular light transmission surface bonded to the first bonding surface 21j of the light guide member 21 with an adhesive. The angle formed between the first surface (first transmission surface) 23a and the second bonding surface 23c is equal to the angle ε formed between the second reflection surface 21b of the light guide member 21 and the first bonding surface 21j. The angle formed by the second surface (second transmission surface) 23b and the second bonding surface 23c is equal to the angle β formed by the first reflection surface 21a and the third reflection 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 second joint surface 23c can also transmit the external light GL ′ with high transmittance. However, since the half mirror layer 28 exists in the region corresponding to the fourth reflection surface 21d of the light guide member 21, the second joint surface 23c The external light GL ′ passing through the joint surface 23c 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%.

  FIG. 3D is a cross-sectional view of the surface portions SP5 and SP6 in order to explain the structure of the first surface (first transmission surface) 23a and the structure of the second surface (second transmission surface) 23b of the light transmission member 23. It is the conceptual diagram which expanded partially. The first and second surfaces 23a and 23b are formed by covering 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 forming a coating agent made of resin or the like on the lower ground SF of the main body portion 23s of the light transmitting member 23 by dipping or spray coating.

[C. (Each shape of the light guide member and the light transmitting member)
As shown in FIGS. 4A to 4D, the light guide member 21 constituting the light guide device 20 in FIG. 2A is a trapezoidal prism-like member in plan view. As shown in -5 (D), the pair of left and right light transmitting members 23, 23 constituting the light guide device 20 constitutes an H-shaped support frame 123 in a front view. The pair of left and right light transmissive members 23 and 23 correspond to the light guide member 21 for the left eye and the light guide member 21 for the right eye, respectively, and each light transmissive member 23 has a U-shaped appearance, The light guide member 21 is supported by being fixed so as to be fitted.

  A light guide member 21 shown in FIG. 4 (A) or the like is fitted to the support frame 123 shown in FIG. 5 (A) or the like so as to fill the cut-out portion SP, and a central member 24a provided on the support frame 123 is provided. The upper support member 24b and the lower support member 24c are fixed so as to be sandwiched between them. Thereby, for example, the state shown in FIG. 2B is obtained, and the optical panel 110 of FIG. 1 is manufactured as a whole. The central member 24a of the support frame 123 is formed with a cutout 24x for fitting a nose pad. Further, connecting portions 24e and 24f provided with fixing holes and the like for connecting the projection optical system 12 and the like of the image forming apparatus 10 are formed at the tips of the support members 24b and 24c provided on the support frame 123.

  Of the main body portion 23s of the support frame 123 or the light transmitting member 23 shown in FIG. 5A and the like, the second joint surface 23c and the fitting surfaces 24j and 24k will be described in detail later, but bubbles are removed from the joint portion. From this point of view, the base surface is roughened. Of the main body portion 21s of the light guide member 21 shown in FIG. 4A and the like, the first joint surface 21j, the first side surface 21e, the second side surface 21f, and the support surfaces 21q and 21r are also roughly combined. It can be a surface.

  Of the main body portion 21 s of the light guide member 21, the base surface corresponding to the first reflecting surface 21 a and the second reflecting surface 21 b will be described in detail later. From the viewpoint of ensuring the adhesion of the hard coat layer 27, the rough surface is used. It has become a simplified surface. Of the main body portion 23 s of the light transmitting member 23, the ground surface corresponding to the first surface 23 a and the second surface 23 b is also a roughened surface from the viewpoint of ensuring the adhesion of the hard coat layer 27. Yes.

  In the above, whether or not the surface is a roughened surface is determined based on the surface roughness, and the surface roughness is higher than the surface roughness of the completed first reflecting surface 21a, second reflecting surface 21b, and the like. Is getting bigger.

[D. Production of light guide device]
In order to manufacture the light guide device 20, the two light guide members 21 and the support frame 123 constituting the light guide device 20 are prepared in advance. When the main body portion 21s of the light guide member 21 is formed, the lower ground (the surface of the main body portion 21s) of the first reflecting surface 21a and the second reflecting surface 21b is roughened for a later hard coat process. . Further, when the support frame 123 is formed, the second bonding surface 23c is roughened for the subsequent bonding process, and the lower ground (the main body portion) for the first surface 23a and the second surface 23b for the subsequent hard coating process. 23s surface) is roughened.

  Next, the two light guide members 21 are sequentially joined to the support frame 123. In addition, before joining the two light guide members 21 to the support frame 123, the half mirror layer 28 is formed in advance on the partial region PA0 of the first joint surface 21j of each light guide member 21 (FIG. 4 ( A)).

  First, the first light guide member 21 is joined to one light transmission member 23 of the support frame 123. Specifically, an adhesive made of an ultraviolet curable resin is applied and spread on the second joint surface 23c and the fitting surfaces 24j and 24k of one (for example, the right half) of the light transmitting member 23. That is, a certain amount of adhesive is applied by the dispenser so as to spread over the second bonding surface 23c and the like. Then, the first light guide member 21 is fitted into the cut-out portion SP of the light transmission member 23. Thereby, the 1st light guide member 21 is arrange | positioned so that the 1st junction surface 21j may oppose the half mirror layer 28 and remaining area (other area | region) PA of the light transmissive member 23. FIG. At this time, the fitting surface 24j of the upper support member 24b provided on one light transmission member 23 and the first side surface 21e and the support surface 21q of the light guide member 21 are arranged to face each other, and the lower support member 24c is fitted. The mating surface 24k, the second side surface 21f of the light guide member 21, and the support surface 21r are disposed to face each other. Thereafter, the first joint surface 21j of the first light guide member 21 and the second joint surface 23c of the one light transmission member 23 are pressed against the second joint surface 23c and the like, and are slid together, thereby mainly the first joint surface 21j and the second joint surface 23c. Expel bubbles associated with the adhesive in between. Finally, curing light that is ultraviolet rays is applied to the adhesive that is spread thinly between the first and second bonding surfaces 21j and 23c. Thereby, the adhesive between the first and second bonding surfaces 21j and 23c is cured, and the bonding between the first light guide member 21 and the one light transmitting member 23 is completed. Since the curing light, which is ultraviolet light, is also applied to the support members 24b and 24c, the fitting surface 24j of the upper support member 24b provided on the light transmission member 23, the first side surface 21e and the support surface 21q of the light guide member 21. Are joined, and the fitting surface 24k of the lower support member 24c is joined to the second side surface 21f and the support surface 21r of the light guide member 21. At this time, the adhesive is filled not only between the half mirror layer 28 and the second bonding surface 23c but also between the remaining area PA and the second bonding surface 23c, and the adhesive layer CC is formed by curing of the adhesive. Therefore (see FIG. 3D), the bonding strength between the first bonding surface 21j of the first light guide member 21 and the second bonding surface 23c of the one light transmission member 23 is increased. Further, as described above, the first light guide member 21 is fixed so as to be sandwiched from above and below by the support members 24b and 24c, and the support strength by the one light transmission member 23 is enhanced.

  The process of joining the second light guide member 21 to the other light transmitting member 23 of the support frame 123 is the same, and the second joining surface 23c and the fitting surface 24j of the other (for example, the left half) light transmitting member 23 are the same. An ultraviolet curable adhesive is applied onto 24k, the first joining surface 21j, the half mirror layer 28, and the remaining area PA face each other, and the fitting surfaces 24j, 24k of the support members 24b, 24c and the light guide member The two side surfaces 21e and 21f and the two support surfaces 21q and 21r are arranged so as to face each other. Thereafter, the second light guide member 21 is rubbed against the other light transmitting member 23 side with an appropriate force to drive out bubbles in the adhesive. Finally, the curing light which is ultraviolet rays is irradiated to the adhesive spread thinly. Thereby, the adhesive between the first joint surface 21j and the second joint surface 23c, and between the fitting surfaces 24j and 24k, both side surfaces 21e and 21f of the light guide member 21, and both support surfaces 21q and 21r. The adhesive is cured, and the joining of the second light guide member 21 and the other light transmission member 23 is completed.

  FIG. 6 is an enlarged cross-sectional view for explaining a joint portion between the light transmission member 23 and the light guide member 21, and is a more detailed view of FIG. As illustrated, the main body portion 21s of the light guide member 21 and the main body portion 23s of the light transmitting member 23 are connected by the adhesive layer CC formed between the first and second bonding surfaces 21j and 23c. Here, with respect to the remaining residual area PA, the first and second joining surfaces 21j and 23c that are substantially mirror surfaces are directly connected via the adhesive layer CC, and it is relatively easy to ensure the joining strength. On the other hand, in the central partial area PA0, the half mirror layer 28 exists between the first bonding surface 21j and the adhesive layer CC, and the half mirror layer 28 is formed by vapor deposition or the like and has a relatively weak adhesive force. Therefore, it is not easy to ensure the bonding strength. As a result, the light guide member 21 and the light transmission member 23 are firmly bonded mainly in the remaining residual area PA, and the strength of the light guide device 20 combining the light guide member 21 and the light transmission member 23 is sufficient. It will be expensive.

  In the case of the present embodiment, a rough surface SR having fine irregularities (undulations) 41 is formed as a non-smooth surface on the second joint surface 23c, which is the lower ground on the light transmitting member 23 side. The rough surface (non-smooth surface) SR is formed, for example, by performing a roughening process on the transfer surface of the molding die of the main body portion 23s in advance. The rough surface SR is also formed by, for example, subjecting the main body portion 23s to a roughening process such as sand blasting, chemical etching, or the like, or a surface modification process.

  The depth of the fine irregularities (undulations) 41 constituting the rough surface SR is, for example, about several μm to several tens of μm (specifically, 20 μm or more). Although exaggerated in the drawings, the thickness of the half mirror layer (semi-transmissive reflective film) 28 is, for example, about several tens of μm, and the thickness of the adhesive layer CC is, for example, about 50 to 100 μm. In a specific example, the refractive index of the main body portion 23s of the light transmitting member 23 and the refractive index of the adhesive layer CC are substantially equal, and the difference between them is, for example, 0.02 or less. Thereby, it is possible to prevent the external light GL ′ from being disturbed by the presence of the rough surface SR.

  As described above, when the second bonding surface (base surface) 23c is the rough surface SR, the adhesiveness and wettability of the adhesive are improved, and the adhesive is spread on the second bonding surface 23c. In addition, even if the viscosity of the adhesive is lowered, the adhesive can be spread relatively uniformly. In other words, the second bonding surface 23c is inclined with respect to the first surface 23a and the like, and when an adhesive is applied on the second bonding surface 23c, liquid dripping is likely to occur when the viscosity is lowered, and thickness is increased when the viscosity is increased. Becomes non-uniform and bubbles tend to remain on the joint surface. On the other hand, when the second bonding surface 23c is a rough surface SR, even if an adhesive having a relatively low viscosity is applied, liquid dripping hardly occurs and the spread adhesive is kept relatively uniform. It is difficult for air bubbles to accumulate between the joint surface 21j and the second joint surface 23c, and it is possible to easily suppress bubbles remaining in the adhesive layer CC after the joint surfaces 21j and 23c are joined. In addition, as a resin used as the adhesive layer CC, an ultraviolet curable resin or the like can be used.

  Although a specific description is omitted, the fitting surfaces 24j and 24k of the light transmitting member 23 are also rough surfaces SR having fine irregularities 41 as a base surface. By making the mating surfaces (base surfaces) 24j and 24k into the rough surface SR, the adhesiveness and wettability of the adhesive are improved. When the adhesive is spread on the mating surfaces 24j and 24k, the adhesive surface is bonded. Even if the viscosity of the agent is lowered, it is possible to spread the adhesive relatively uniformly, and it is possible to easily suppress the bubbles remaining at the joint.

[E. Hard coat layer coating)
FIG. 7 is an enlarged cross-sectional view for explaining the surface of the light guide member 21 and is a more detailed view of FIG. As illustrated, the first reflecting surface 21 a and the second reflecting surface 21 b are formed by covering the lower ground SF of the main body portion 21 s with a hard coat layer 27. Here, a rough surface SR having fine unevenness (undulations) 141 is formed as a non-smooth surface on the lower ground SF of the main body portion 21 s of the light guide member 21. The rough surface (non-smooth surface) SR is formed, for example, by performing a roughening process on the transfer surface of the molding die of the main body portion 21s in advance. The rough surface SR is also formed by, for example, subjecting the main body portion 21s to a roughening process such as sandblasting, etching with chemicals, or the like, or a surface modification process.

  The depth of the fine unevenness (undulations) 141 constituting the rough surface SR of the main body portion 21s is, for example, about several μm (specifically, 2 to 3 μm). In addition, although exaggerated in drawing, the thickness of the hard-coat layer 27 is about 5-10 micrometers, for example, and can fully fill an unevenness | corrugation. In a specific example, the refractive index of the main body portion 21s of the light guide member 21 and the refractive index of the hard coat layer 27 are substantially equal, and the difference between them is, for example, 0.02 or less. Thereby, it is possible to prevent the image light GL or the like propagating in the light guide member 21 from being disturbed by the presence of the rough surface SR.

  As described above, the adhesiveness of the hard coat layer 27 can be increased and the scratch resistance of the hard coat layer 27 can be improved by making the lower surface SF of the main body portion 21 s of the light guide member 21 as the rough surface SR. In particular, when the main body portion 21s of the light guide member 21 is shaped with an ultraviolet curable resin, the adherence of the hard coat layer 27 may be reduced. However, by making the base surface SF a rough surface SR, the main body portion Regardless of the material of 21s, the adhesion of the hard coat layer 27 can be enhanced.

  In addition, if the main body portion 21s of the light guide member 21 is formed of a material having extremely high adhesion to the hard coat layer 27, a certain degree of adhesion can be secured even if the base surface SF is not the rough surface SR. However, in the virtual image display device 100 as in the present embodiment, it is necessary to form the main body portion 21s of the light guide member 21 by injection molding, achieve low flatness with high water absorption, and the hard coat layer 27. It is not easy to secure the adhesion to. For this reason, the adhesiveness of the hard-coat layer 27 can be improved regardless of the material of the main-body part 21s by roughening the main-body part 21s base surface SF.

  As a material of the hard coat layer 27, for example, a thermosetting silicone resin is used. The material of the hard coat layer 27 may be a composite of fine particles of an inorganic material having scratch resistance such as silica and a binder resin. In addition, as a material of the main body portion 21s of the light guide member 21, in consideration of the convenience of injection molding and low water absorption, adhesion or joining with the light transmission member 23 with sufficient strength, and high transparency, For example, a (meth) acrylate compound obtained by copolymerizing a (meth) acrylate monomer with another polymerizable monomer is used. Specific examples of the (meth) acrylate monomer-based monomer include 2,2-bis (3,5-dibromo-4- (meth) acryloyloxyethoxyphenyl) propane, 2,2-bis (4- (meth) acryloyloxy Ethoxyphenyl) propane, 2,2-bis [4- (β-hydroxy-γ- (meth) acryloyloxy) propoxyphenyl] propane and the like. Specific examples of other polymerizable monomers copolymerized with the (meth) acrylate compound include aromatic monofunctional vinyl monomers such as styrene, chlorostyrene, bromostyrene, and α-methylstyrene. In a specific example, a plastic based on polymethacrylstyrene was used. For example, polycarbonate is inferior in terms of transparency, acrylic is inferior in terms of hygroscopicity, and cycloolefin is inferior in terms of adhesiveness.

  FIG. 8 is an enlarged cross-sectional view for explaining the surface of the light transmission member 23, which is a more detailed view of FIG. As illustrated, the first surface 23 a and the second surface 23 b are formed by covering the lower ground SF of the main body portion 23 s with a hard coat layer 27. Here, a rough surface SR having fine irregularities (undulations) 141 is formed as a non-smooth surface on the lower ground SF of the main body portion 23s of the light transmitting member 23. The rough surface (non-smooth surface) SR is formed, for example, by performing a roughening process on the transfer surface of the molding die of the main body portion 23s in advance. The rough surface SR is also formed by, for example, subjecting the main body portion 23s to a roughening process such as sand blasting, chemical etching, or the like, or a surface modification process.

  The depth of the fine irregularities (undulations) 141 constituting the rough surface SR of the main body portion 23s is, for example, about several μm (specifically, 2 to 3 μm). The hard coat layer 27 has a thickness of, for example, about 5 to 10 μm, and can sufficiently fill the unevenness. In a specific embodiment, the difference between the refractive index of the main body portion 21s of the light guide member 21 and the refractive index of the adhesive layer CC is set to 0.02 or less, for example. Thereby, it is possible to prevent the external light GL ′ passing through the light transmission member 23 from being disturbed by the presence of the rough surface SR.

  As described above, by setting the lower surface SF of the main body portion 21s of the light transmitting member 23 to the rough surface SR, the adhesion of the hard coat layer 27 is enhanced, and the scratch resistance of the hard coat layer 27 can be enhanced. In addition, as the material of the main body portion 21 s of the light transmitting member 23, as in the case of the light guide member 21, the convenience of injection molding and low water absorption, and adhesion or bonding with the light transmitting member 23 with sufficient strength are possible. Considering that the transparency is high, for example, a (meth) acrylate compound obtained by copolymerizing a (meth) acrylate monomer with another polymerizable monomer is used. In a specific example, a plastic based on polymethacrylstyrene was used.

[F. Overview of optical path of image light)
Hereinafter, an outline of an optical path of image light in the virtual image display device 100 will be described.

  FIG. 9A illustrates the 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 incident on the observer's eye EY in a parallel light flux state with an angle φ ₁ tilted from above. 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 beam passes through B3 and is incident on the observer's eye EY with an angle φ ₂ (| φ ₂ | = | φ ₁ |) tilted from below in a parallel light flux state. 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. 9B is a diagram illustrating an optical path in the second direction D2 corresponding to the cross section CS2 of the liquid crystal display device 32. FIG. 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 at an angle 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 beam passes through B2 and the light emitting portion B3, and enters the observer's eye EY with an angle θ ₂ (| θ ₂ | = | θ ₁ |) inclined from the left direction in a parallel light flux state. 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 lateral direction of the second direction D2 or the confinement direction DW2, 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 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.

[G. (The optical path of image light in the horizontal direction)
FIG. 10 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 are totally reflected 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. It is emitted as a parallel light beam by theta ₁ slope.

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. 10, when the light guide member 21 is developed, the virtual first surface 121a corresponding to the first reflection surface 21a and when the light guide member 21 is deployed, the virtual surface corresponding to the second reflection 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 that is present in the vicinity of the incident equivalent surfaces IS ′ and IS ″ at two different positions.

  FIG. 11A is a diagram conceptually illustrating a display surface of the liquid crystal display device 32, and FIG. 11B is a diagram conceptually illustrating a virtual image of the liquid crystal display device 32 that can be seen by an observer. 11 (C) and 11 (D) are diagrams illustrating partial images constituting a virtual image. A rectangular image forming area AD provided in the liquid crystal display device 32 shown in FIG. 11A 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 forming 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 projection image (virtual image) IM1 in the liquid crystal display device 32 illustrated in FIG. 11A includes the first display point P1 at the right end of the liquid crystal display device 32, for example. 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. The 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 SI shown in FIG. 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 SI is prevented from being displaced or blurred due to the superimposition of the two projection images IM1 and IM2. be able to.

  According to the virtual image display device 100 of the above-described embodiment, at least a part of the base surface SF covered with the light guide member 21 is roughened, and thus, for example, the light guide member 21 and other optical members. When the light transmitting member 23 is joined, even if the viscosity of the adhesive covering the base surface SF is lowered to make it difficult for bubbles to be generated, dripping of the adhesive is less likely to occur. Further, according to the virtual image display device 100 of the present embodiment, since at least a part of the base surface SF covered with the light guide member 21 is roughened, for example, the first and second reflecting surfaces 21a, When forming the hard coat layer 27 that forms the exposed external surface 21b or the like and covers the base surface SF, the adhesion of the hard coat layer 27 can be ensured regardless of the material of the base body portion 21s. In addition, since at least a part of the base surface SF covered with the light transmitting member 23 is roughened, for example, externally exposed surfaces such as the first and second surfaces 23a and 23b are formed to form the base surface SF. When the hard coat layer 27 to be coated is formed, the adhesion of the hard coat layer 27 can be ensured regardless of the material of the base body portion 23s.

  In the above description, the total number of reflections of the image light GL11 and GL12 emitted from the first area 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 3 in total. The total number of reflections of the image light GL21 and GL22 emitted from the second area A20 including the second display point P2 on the left side of the liquid crystal display device 32 by the first and second reflecting surfaces 21a and 21b is 5 times 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 is 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.

  FIG. 12A is a diagram illustrating a light guide member 221 obtained by modifying 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 two reflection angles with respect to the first and second reflecting surfaces 21a and 21b and propagates in two modes. As shown in the light guide member 221 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, synthesized at the position of the observer's eye EY, and recognized as a virtual image. In this case, as shown in FIG. 12B, a total reflection projection image IM21 is formed on the left side of the effective display area A0, for example, and the total reflection projection is performed on the left side of the effective display area A0. An image IM22 is formed, and a total reflection projected image IM23 is formed, for example, seven times in total on the right side of the effective display area A0.

  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 curved and can be replaced with a hologram sheet covered with a protective layer. When replacing the half mirror layer 28 with a hologram sheet, a multi-layered diffraction that uses a highly coherent illumination device 31 and individually processes, for example, three color images formed by the liquid crystal display device 32 as the hologram sheet. Use a sheet.

  According to the virtual image display device 100 of the above embodiment, since the second bonding surface 23c covered with the adhesive layer CC in the light transmitting member 23 is roughened, for example, the light guide member 21 and the light transmitting member 23 When bonding the adhesive, even if the viscosity of the adhesive covering the second bonding surface 23c is lowered to make it difficult for bubbles to be generated, dripping of the adhesive is less likely to occur. Further, according to the virtual image display device 100 of the present embodiment, since at least a part of the base surface SF covered with the light guide member 21 is roughened, for example, the first and second reflecting surfaces 21a, When forming the hard coat layer 27 that forms the exposed external surface 21b or the like and covers the base surface SF, the adhesion of the hard coat layer 27 can be ensured regardless of the material of the base body portion 21s. In addition, since at least a part of the base surface SF covered with the light transmitting member 23 is roughened, for example, externally exposed surfaces such as the first and second surfaces 23a and 23b are formed to form the base surface SF. When the hard coat layer 27 to be coated is formed, the adhesion of the hard coat layer 27 can be ensured regardless of the material of the base body portion 23s.

[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.

  As shown in FIG. 13, in the case of the second embodiment, the half mirror layer 28 is formed not on the light guide member 21 but on the light transmitting member 23 side. For this reason, instead of the second joint surface 23 c of the light transmission member 23, the first joint surface 21 j of the light guide member 21 is a rough surface SR having fine irregularities 41. In this case, even if an adhesive having a relatively low viscosity is applied to the first joint surface 21j, dripping does not easily occur, and the spread adhesive is kept relatively uniform. Therefore, the first joint surface 21j and the second joint It becomes easy to expel air bubbles from the joint surface 23c, and it is possible to easily suppress the air bubbles from remaining in the adhesive layer CC after the joint surfaces 21j and 23c are joined.

[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. 14A to 14C includes the image forming apparatus 10 and a light guide device 520 as a set. The light guide device 520 includes a light guide member 521 and a support member 529. The light guide member 521 includes a light guide body member 20a and an angle conversion unit 523 which is an image extraction unit. 14A corresponds to the AA cross section of the light guide member 521 shown in FIG.

  The overall appearance of the light guide member 521 is formed by a light guide body member 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 a first side surface 21e and a second side surface 21f that are adjacent to the first, second, and third reflection surfaces 21a, 21b, and 21c and that face each other. Further, the light guide member 521 has a prism portion PS formed so as to extend the light guide body member 20a at one end in the longitudinal direction and a third reflecting surface 21c associated therewith, and is guided at the other end in the longitudinal direction. It has a structure having an angle conversion section 523 constituted by a large number of micromirrors embedded in the light main body member 20a. 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. 14 ( 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 light guide main body member 20a is formed of a light transmissive resin material or the like, and takes in the image light from the image forming apparatus 10 on a back side or an observer side plane that is parallel to the XY plane and faces the image forming apparatus 10. It has a light incident surface IS and a light emitting surface OS that emits image light toward the observer's eye EY. The light guide body member 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 the inclined surface RS. . 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 guides the image light by bending 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. The main body member 20a is securely coupled. The light guide main body member 20a extends from the third reflecting 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 light guide main body member 20a and are two planes facing each other and extending in parallel to the XY plane. Each of the image lights bent at the incident part 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 provided with the angle conversion unit 523.

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

  As shown in FIG. 14B, the support member 529 is a part of a support frame (not shown) for supporting the light guide member 521, and includes an upper support member 24b and a lower support member 24c extending in the X direction. The light guide member 521 is sandwiched and fixed.

  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. Note that the light guide device 520 in the third 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. 14A, 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 is 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 reflecting surface 21a of the light guide member 521 at the maximum 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. 15).

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. 15).

  As shown in FIG. 15, 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. 16, the angle conversion unit 523 joins a relatively thick plate-like joining member 521n extending from the entrance side and a relatively thin plate-like joining member 523n extending from the back side in the light guide main body member 20a. It has the structure. The bonding member 521n has a first bonding surface 21j on the front side or the outside, and the bonding member 523n has a second bonding surface 523c on the back side or the observer side. On the first bonding surface 21j of the bonding member 521n, a half mirror layer 28 that is a semi-transmissive reflection film is formed on a local partial region. Here, the region where the half mirror layer 28 is formed is the same as the partial region PA0 shown in FIG. In the light guide member 521, the joining member 521n and the joining member 523n are joined to each other by the adhesive layer CC in the partial area PA0 and the periphery thereof, like the light guide member 21 and the light transmitting member 23 in FIG. In this case, the second bonding surface (base surface) 523c of the bonding member 523n is a rough surface SR having fine irregularities 41. By setting the second bonding surface 523c to the rough surface SR, when the adhesive is applied and spread on the second bonding surface 523c, the adhesive having a low viscosity can be spread relatively uniformly, and bubbles are generated in the bonding portion. It can be easily suppressed from remaining.

  The surfaces of the bonding member 521n and the bonding member 523n (specifically, the reflection surfaces 21a and 21b) cover the lower ground SF of the main body portions 21s and 23s with the hard coat layer 27 as in FIGS. It is formed by. Here, a rough surface SR having fine irregularities 141 is formed as a non-smooth surface on the lower ground SF of the main body portion 21s of the light guide member 521. Thus, by making the lower surface SF of the main body portions 21s and 23s of the bonding member 521n and the bonding member 523n into the rough surface SR, the adhesion of the hard coat layer 27 is increased, and the scratch resistance of the hard coat layer 27 is improved. be able to. As the material of the main body portions 21s and 23s, for example, methacryl styrene or the like can be used as in the case of the first embodiment.

[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. 17A to 17C includes the image forming device 10 and a light guide device 620 as a set. The light guide device 620 includes a light guide member 621 and a support member 629. The light guide member 621 includes a light guide body member 20a and an angle conversion unit 623 that is an image extraction unit. Note that FIG. 17A corresponds to the AA cross section of the light guide device 620 illustrated in FIG.

  The overall appearance of the light guide member 621 is formed by a light guide main body member 20a which is a flat plate extending parallel to the XY plane in the drawing. In addition, the light guide member 621 includes, as side surfaces, a first reflecting surface 21a, a second reflecting surface 21b, a third reflecting surface 21c, and a first bonding surface 21j. The light guide member 621 includes a first side surface 21e and a second side surface 21f that are adjacent to the first, second, and third reflecting surfaces 21a, 21b, and 21c and that face each other. Further, the light guide member 621 has a prism portion PS formed so as to extend the light guide main body member 20a at one end in the longitudinal direction, and a third reflecting surface 21c associated therewith, and a large number at the other end in the longitudinal direction. It is the structure connected to the angle conversion part 623 comprised by this mirror.

  The light guide main body member 20a is formed of a light-transmitting resin material or the like, and is a light incident surface IS that takes in image light from the image forming apparatus 10 on a back plane parallel to the XY plane and facing the image forming apparatus 10. have. The light guide body member 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 the inclined surface RS. . 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 guides the image light by bending 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. The main body member 20a is securely coupled.

  The first and second reflecting surfaces 21a and 21b of the light guide member 621 are the main surfaces of the flat light guide body member 20a, and are bent at the prism portion PS as two planes facing each other and extending in parallel to the XY plane. Each of the received 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. Thereafter, by repeating this operation, the image light is guided to the back side of the light guide member 621, that is, to the −X side where the angle conversion unit 623 is provided.

  As shown in FIG. 17C, in the light guide member 621, the third reflecting surface 21c and a light incident surface IS described later function as a light incident portion B1. Further, the light guide main body member 20a sandwiched between the first and second reflecting surfaces 21a and 21b of the light guide member 621 and an angle conversion unit 623 described later function as the light guide unit B2. The angle conversion unit 623 functions as the light emission unit B3.

  The angle conversion unit 623 is formed on the back side (−X side) of the light guide member 621 along extension planes of the first and second reflection surfaces 21 a and 21 b. Here, the back end portion of the light guide body member 20 a is a part of the angle conversion unit 623. The angle conversion unit 623 includes a plurality of half mirror layers 28 that are inclined with respect to the first and second reflecting surfaces 21a and 21b and are arranged in parallel with each other at equal intervals. The angle conversion unit 623 reflects the image light incident through the first and second reflecting surfaces 21a and 21b of the light guide main body member 20a at a predetermined angle and passes through the light exit surface OS to the observer's eye EY side. Bend to. That is, the angle conversion unit 623 converts the angle of the image light.

  The light transmission member 323 is a portion obtained by extending the angle conversion unit 623 to the back side (−X side), and is a flat plate member like the light guide main body member 20 a of the light guide member 621.

  In the above, the whole angle conversion part 623 or a part on the entrance side also functions as a part of the light guide part B2 by combining with the light guide main body member 20a. In addition, the entire angle conversion unit 623 or a part on the back side functions as a see-through unit when combined with the light transmission member 323.

  As shown in FIG. 17B, the support member 629 is a part of a support frame (not shown) for supporting the light guide member 621, and includes an upper support member 24b and a lower support member 24c extending in the X direction. The light guide member 621 is sandwiched and fixed.

  The image light emitted from the image forming apparatus 10 and incident on the light guide member 621 from the light incident surface IS is uniformly reflected and bent by the third reflecting surface 21c, and the first and second reflecting surfaces of the light guide member 621 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 623 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 623. 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 620 will be described. In addition, the light guide device 620 in the second 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 620 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. 17A, 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 GL61 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 GL62. Is image light GL63.

The main components of the image lights GL61, GL62, and GL63 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 GL61, GL62, and GL63, the image light GL61 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 GL61 is, while maintaining the standard reflection angle gamma _0, the first and second reflecting surfaces 21a, repeating total reflection at 21b. The image light GL61 is totally reflected N times (N is a natural number) on the first and second reflecting surfaces 21a and 21b, and reaches the central portion 23k of the angle conversion unit 623. The image light GL61 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 GL62 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 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 reflecting surface 21a of the light guide member 21 at the maximum reflection angle γ ₊ and is totally reflected. The image light GL62 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 623. The image light GL62 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 with} respect to the optical axis AX (in the light guide device 620). Injected in a direction inclined by θ ₁₂ ′) (see FIG. 18).

The image light GL63 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 beam 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 GL63 is totally reflected, for example, N + M times on the first and second reflecting surfaces 21a and 21b, and enters the innermost peripheral portion 23h of the angle converting portion 623 (−X side). The image light GL63 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 an angle θ _{13 with} respect to the optical axis AX (in the light guide device 620, θ Injected in a direction inclined by ₁₃ ′) (see FIG. 18).

  As shown in FIG. 19, the angle conversion unit 623 has a structure in which a plurality of prisms 624 are arranged in the X direction at a predetermined pitch. Each prism 624 has a first joint surface 624j on the light exit side and a second joint surface 624c on the light incident side. On the first joint surface 21j of the light guide body member 20a or the first joint surface 624j of each prism 624, a half mirror layer 28 that is a semi-transmissive reflective film is formed on a local partial region. Here, the region where the half mirror layer 28 is formed is the same as the partial region PA0 shown in FIG. In the light guide member 621, the light guide main body member 20a and the angle conversion unit 623 are joined to each other by the adhesive layer CC. Further, the pair of adjacent prisms 624 in the angle conversion unit 623 are joined to each other by the adhesive layer CC. Furthermore, the light transmission member 323 and the angle conversion part 623 are joined to each other by the adhesive layer CC. The second joint surface (base surface) 624 c of each prism 624 and the second joint surface (base surface) 623 c of the light transmission member 323 are rough surfaces SR having fine irregularities 41. As described above, when the second bonding surfaces (base surfaces) 624c and 623c are rough surfaces SR, when the adhesive is applied and spread on the second bonding surfaces 624c and 623c, an adhesive having a low viscosity is compared. Can be spread evenly, and it is possible to easily prevent bubbles from remaining in the joint.

  The surfaces of the light guide body member 20a, the angle conversion unit 623, and the light transmission member 323 (specifically, the reflection surfaces 21a, 21b, etc.) are the same as those of the body portions 21s, 24s, 23s as in FIGS. It is formed by covering the lower ground SF with a hard coat layer 27. Here, a rough surface SR having fine irregularities 141 is formed as a non-smooth surface on the lower ground SF of the main body portion 21 s of the light guide member 21. Thus, by making the lower surface SF of the main body portions 21s and 23s of the bonding member 521n and the bonding member 523n into the rough surface SR, the adhesion of the hard coat layer 27 is increased, and the scratch resistance of the hard coat layer 27 is improved. be able to.

[Others]
Although the present invention has been described with reference to each embodiment, the present invention is not limited to the above-described embodiment, and can be implemented in various modes without departing from the spirit of the present invention. The following modifications are possible.

  In the above description, the first bonding surface 21j and the second bonding surface 23c are bonded to each other by the partial region PA0 and the remaining region PA. However, the first bonding surface 21j and the second bonding surface 23c are bonded only to the remaining region PA. It can also be glued with. In this case, it is possible to bond the entire remaining area PA, but it is also possible to bond at a plurality of bonding areas provided in the remaining area PA. In addition, it is desirable that the second bonding surface 23c is not roughened from the viewpoint of permeability at a portion that is not bonded.

  In the above description, the half mirror layer (semi-transmissive reflective film) 28 is formed in a horizontally long rectangular region. However, the contour of the half mirror layer 28 can be changed as appropriate according to applications and other uses. However, it is desirable that the half mirror layer 28 sufficiently covers the effective area EA.

  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 embodiment, the display brightness of the liquid crystal display device 32 is not particularly adjusted, but the display brightness may be adjusted according to the range and overlap of the projection images IM1 and IM2 as shown in FIG. it can.

  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 light guide devices 20, 520, and 620 including the light incident part B1, the light guide part B2, and the light emitting part B3 are used. However, in the light incident part B1 and the light emitting part B3, the half mirror layer 28 is used. For example, it is not necessary to use a flat half mirror or a flat mirror, and a spherical or aspherical curved mirror can be used to provide a lens function. Further, a hologram element as a virtual semi-transmissive mirror can be arranged instead of the half mirror layer 28 and the like. In this case, the hologram element is also a transflective surface in a broad sense. In addition, an optical function such as condensing can be added to the hologram element.

  FIG. 20 illustrates a modification of the third embodiment shown in FIG. In this modified example, a hologram element is used, and the angle conversion unit 523 is not an array of a large number of reflection units 2c but an element including a hologram layer 902c in which a plurality of hologram elements are stacked.

  Furthermore, as shown in FIG. 21, a prism or block-shaped relay member 1025 separated from the light guide B2 can be used as the light incident part B1, and the incident and outgoing surfaces and the reflective inner surface of the relay member 1025 are lens-like. It can also have a special function. The light guide body 26 constituting the light guide section B2 is provided with first and second reflection surfaces 21a and 21b for propagating the image light GL by reflection. The reflection surfaces 21a and 21b are They do not have to be parallel to each other and can be curved surfaces. The light guide 26 shown in FIG. 21 is joined to the light transmission member 23, and a half mirror layer 28 is provided at the joint of both. Also in this case, as in the case of the first embodiment, a rough surface SR (see FIG. 6) having fine irregularities (undulations) is formed on the second joint surface 23c, which is the lower ground on the light transmitting member 23 side, for example. Thus, when the light guide 26 and the light transmitting member 23 are joined, the adhesive dripping is less likely to occur. Further, since the base surface covered with the hard coat layer 27 in the light guide 26 is roughened, the adhesion of the hard coat layer 27 is performed regardless of the material of the main body portion 21 s which is the base of the light guide 26. Sex can be secured. The relay member 1025 can also be covered with the hard coat layer 27. In this case, the adhesion of the hard coat layer 27 can be improved by roughening the ground surface of the relay member 1025.

  In the above description, the half mirror layer 28 as the anti-transmission reflection film is formed of a metal reflection film or a dielectric multilayer film, and can be replaced with a hologram element. It can also be replaced with a translucent sheet.

  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.

  AX1, AX2 ... Optical axis, B1 ... Light incident part B2 ... Light guide part, B3 ... Light emission part, B4 ... Transparent part, CC ... Adhesive layer, EY ... Eye, GL ... Image light, GL '... External light, GL1 , GL2 ... image light, IM1, IM2 ... projected image, IS ... light incident surface, OS ... light exit surface, PA ... remaining region, PA0 ... partial region, PA1, PA2 ... peripheral region, PS ... prism part, RS ... slope SF ... Rough surface, SR ... Rough surface, 10 ... Image forming device, 11 ... Image display device, 12 ... Projection optical system, 20 ... Light guide device, 20a ... Light guide body member, 21 ... Light guide member, 21a ... First reflective surface, 21b ... second reflective surface, 21c ... third reflective surface, 21d ... fourth reflective surface, 21j ... first joint surface, 21s, 24s, 23s ... main body portion, 23 ... light transmitting member, 23a ... A first surface (first transmission surface), 3b: Second surface (second transmission surface), 23c: Second bonding surface (base surface), 25: Mirror layer, 27 ... Hard coat layer, 28 ... Half mirror layer, 31 ... Illumination device, 31a ... Light source, 34 DESCRIPTION OF SYMBOLS ... Drive control part, 41, 141 ... Concavity and convexity, 100 ... Virtual image display apparatus, 100A, 100B ... Display apparatus, 110 ... Optical panel, 123 ... Support frame

Claims (11)

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 and a light guide that guides the image light taken from the light incident part by total reflection at first and second reflection surfaces that extend opposite to each other. A light guide member, and a light emitting part that takes out the image light that has passed through the light guide part to the outside,
A virtual image display device in which at least a part of a base surface covered with the light guide member is roughened. A light transmission member that enables observation of external light by being joined to the light guide member;
2. The virtual image display device according to claim 1, wherein at least a part of a joint surface as the base surface covered with the light guide member and the light transmission member is roughened.   The ground surface which contacts the hard-coat layer exposed in the said light guide member and the said light transmissive member, and the contact bonding layer between the said light guide member and the said light transmissive member is roughened of Claim 2. Virtual image display device. The light guide member has a transflective film that bends the image light and transmits the external light on a partial region of the first joint surface joined to the light transmissive member,
The light transmitting member has a second bonding surface bonded to the first bonding surface via an adhesive layer,
The virtual image display device according to claim 3, wherein a portion of at least one of the first bonding surface and the second bonding surface that is in contact with the adhesive layer disposed between the first bonding surface and the second bonding surface is roughened as the base surface. . The light incident portion has a third reflecting surface that forms a predetermined angle with respect to the first reflecting surface;
The light emitting part has a first joint surface that is provided with a fourth reflective surface that forms a predetermined angle with respect to the first reflective surface and is in contact with the adhesive layer,
The light transmission member includes a first transmission surface disposed at a position extending the first reflection surface, a second transmission surface disposed at a position extending the second emission surface, and the adhesive layer. A second bonding surface facing the first bonding surface;
The transflective film is formed on the fourth reflective surface;
The virtual image display device according to claim 4, wherein the second bonding surface is roughened.   The virtual image display according to claim 5, wherein a main body side in contact with the hard coat layer formed on the first and second reflection surfaces and the first and second transmission surfaces is roughened as the base surface. apparatus.   The virtual image display device according to claim 5, wherein a main body part constituting the light guide member is formed of an ultraviolet curable resin and has the base surface roughened at least partially.   The said light guide member, the said light transmissive member, the said hard-coat layer, and the said contact bonding layer are formed from the material which has the same refractive index, It is any one of Claim 3-7 Virtual image display device.   The virtual image display device according to any one of claims 3 to 8, wherein the main body portion of the light guide member and the main body portion of the light transmission member are formed of methacryl styrene.   10. The virtual image display device according to claim 1, wherein a surface roughness of at least a part of the base surface is larger than a surface roughness of the first and second reflecting surfaces. 11. An image display device that forms image light, a projection optical system that forms a virtual image by the image light emitted from the image display device, a light incident unit that takes in the image light that has passed through the projection optical system, and A light guide part that guides the image light taken in from the light incident part by total reflection on the first and second reflection surfaces extending opposite to each other, and a light emission part that takes out the image light that has passed through the light guide part to the outside And a method of manufacturing a virtual image display device comprising a light guide member having:
A first step of roughening at least part of the lower ground of the light guide member;
A virtual image display device manufacturing method, comprising: a second step of covering the roughened base surface.

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