JP2016142838A - Translucent reflection sheet and display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a translucent reflection sheet and a display device capable of suppressing blur in environmental light.SOLUTION: A translucent reflection sheet 20 transmits environmental light through the back surface thereof and reflects image light to allow the image light and the environmental light to exit from a light-exiting surface; and the sheet includes a first optical shape layer 22 where a plurality of unit optical shapes 30 is arrayed and a second optical shape layer 23 having a light-exiting surface and layered on the unit optical shape 30 side of the first optical shape layer 22. The unit optical shape 30 is constituted by a first inclined surface 30a inclined with respect to the light-exiting surface and a second inclined surface 30b opposing to the first inclined surface 30a and inclined with respect to the light-exiting surface. A translucent reflection layer 25 that reflects a part of the image light and transmits other light is formed on the first inclined surface 30a; and a fine concavo-convex shape is formed on the second inclined surface 30b.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a transflective reflection sheet and a display device that transmit external light such as a background and reflect video light.

Conventionally, there has been proposed a head-mounted display device that allows an observer to observe an image source such as an LCD (Liquid Crystal Display) via an optical system (for example, Patent Document 1).
In such a head-mounted display device, for example, a light guide plate is arranged at a position facing the image source, and the image light displayed by the image source is positioned at the position corresponding to the eyes of the observer by the light guide plate. To the viewer side through the reflective layer. In such a display device, the viewer's field of view is blocked by the displayed image, so a magic mirror is used for the reflective layer, etc., so that the image light and the external light can be seen so as to overlap each other. There is a case.

Here, the light guide plate is provided with a plurality of unit optical shapes arranged in the light guide direction. The unit optical shape is formed in a substantially triangular shape in cross section parallel to the arrangement direction and parallel to the thickness direction of the light guide plate. It consists of a surface.
The light guide plate having such a unit optical shape is manufactured, for example, by forming another layer on the surface of the layer having the unit optical shape so as to cover the unit optical shape. Therefore, the light guide plate is composed of a layer on the back side and a layer on the viewer side (light output side) with each surface of the unit optical shape as a boundary. The back side layer and the viewer side layer are formed with the same refractive index in order to avoid refraction of transmitted light, etc., but even if the same material is used, the refractive index is very small. Differences can occur. In addition, depending on the configuration of the light guide plate, the same resin cannot be used or it cannot be molded under the same conditions, so the refractive index may not be completely the same.

  Here, external light incident from the back surface of the light guide plate may be incident on the facing surface facing the reflecting surface of the unit optical shape, and a minute amount is formed between the back surface layer and the viewer side layer. When there is a large difference in refractive index, the external light is totally reflected on the surface and reaches the observer side in a state inclined with respect to the normal direction of the light exit surface, resulting in a double image, that is, a ghost. In some cases, however, the light from the outside world becomes unclear.

Special table 2011-509417 gazette

  An object of the present invention is to provide a transflective reflection sheet and a display device that can prevent the external light from becoming unclear.

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is a transflective reflection sheet (20) that transmits external light from the back, reflects video light, and emits the video light and external light from a light exit surface. A first optical shape layer (22) in which a plurality of optical shapes (30) are arranged, and a second optical shape layer having the light exit surface and stacked on the unit optical shape side surface of the first optical shape layer (23), and the unit optical shape is a first inclined surface (30a) inclined with respect to the light exit surface, and a second slope inclined with respect to the light exit surface, facing the first inclined surface. A cross-sectional shape in a section parallel to the direction in which the image light is emitted and parallel to the arrangement direction of the unit optical shapes is formed in a substantially triangular shape, and the first inclined surface Includes a semi-transmissive type that reflects part of the image light and transmits the other part. Picolinimidate (25) is formed, on the second inclined surface, the fine irregularities are formed, a semi-transmission type reflection sheet according to claim.
According to a second aspect of the present invention, in the transflective reflection sheet (20) according to the first aspect, the concave-convex shape is such that the unit shape (31) is along the second inclined surface (30b). When the arrangement pitch of the unit shapes is P2, the distance between the bottom and the top of the unit shapes is h2, and A = h2 / P2, 0.05 ≦ A It is a transflective reflection sheet characterized by satisfying ≦ 0.5.
A third aspect of the present invention is a display device comprising: the transflective reflection sheet (20) according to the first or second aspect; and an image source (11) that emits image light to the transflective reflection sheet. (1).

  According to the present invention, it is possible to prevent external light from becoming unclear.

It is a figure explaining the head mounting type display device of an embodiment. It is a figure explaining the detail of the light-guide plate of embodiment. It is a figure which shows an example of the locus | trajectory of the external light in the 2nd inclined surface of a unit optical shape. It is a figure explaining the locus | trajectory of the external light which permeate | transmits the 2nd inclined surface of embodiment. It is a figure which shows an example of the manufacturing method of the light-guide plate of embodiment. It is a figure which shows the shape of the 2nd inclined surface of a deformation | transformation form. It is a figure explaining the transflective reflection sheet of a deformation | transformation form.

Embodiments of the present invention will be described below with reference to the drawings. In addition, each figure shown below including FIG. 1 is the figure shown typically, and the magnitude | size and shape of each part are exaggerated suitably for easy understanding.
Numerical values such as dimensions and material names of the respective members described in the present specification are examples of the embodiment, and the present invention is not limited thereto, and may be appropriately selected and used.
In this specification, terms that specify shape and geometric conditions, for example, terms such as parallel and orthogonal, are strictly meanings, have similar optical functions, and can be regarded as parallel and orthogonal It also includes a state having an error of.

(Embodiment)
FIG. 1 is a diagram illustrating a head-mounted display device 1 according to this embodiment. FIG. 1 is a view of the display device 1 as viewed from above in the vertical direction.
In addition, in the figure shown below including FIG. 1 and the following description, in order to make an understanding easy, in a state where the viewer wears the display device 1 on the head, the vertical direction is the Z direction, and the horizontal direction is Let it be X direction and Y direction. Of these horizontal directions, the direction in which the video light entering the light guide plate is guided (the left-right direction of the light guide plate) is the X direction, and the direction orthogonal to the direction (the thickness direction of the light guide plate, the front direction) is Y. The direction. The −Y side in the Y direction is the observer side, and the + Y side is the back side.

The display device 1 is a so-called head mounted display that an observer wears on the head and displays an image in front of the eyes of the observer. As shown in FIG. 1, the head-mounted display device 1 of the present embodiment includes a video source 11, a projection optical system 12, and a light guide plate 20 inside a glasses frame (not shown). When the observer wears the glasses frame on the head, the image of the image source 11 can be visually recognized by the observer via the light guide plate 20 or the like. Specifically, the display device 1 enters video light displayed on the video source 11 into the light guide plate 20 through the projection optical system 12 and guides it in the + X direction within the light guide plate 20. The image information is displayed in front of the eyes E of the observer who wears the display device 1 on the head by reflecting in the -Y direction orthogonal to the light direction.
In addition, the display device 1 has a so-called see-through function in which a part of light from the outside world is transmitted through the light guide plate 20 to reach the observer side, and the image and the light from the outside world are superimposed. In the present embodiment, an example in which a transflective reflection sheet is applied to the light guide plate 20 will be described.

The video source 11 is a micro display that displays video light. For example, a transmissive liquid crystal display device, a reflective liquid crystal display device, an organic EL, or the like can be used. For example, a micro display having a diagonal of 1 inch or less is used as the video source 11.
The projection optical system 12 is an optical system composed of a plurality of lens groups that project image light emitted from the image source 11 as parallel light.
The light guide plate 20 is a substantially flat transparent member that guides light. In this embodiment, the light guide plate 20 is formed in a trapezoidal column shape in which the shape viewed from the vertical direction (Z direction) is formed in a substantially trapezoidal shape. . As shown in FIG. 1, the light guide plate 20 is parallel to each other and faces the first total reflection surface 20 b and the second total reflection surface 20 c facing each other, and the first total reflection surface 20 b and A reflecting surface 20a inclined with respect to the second total reflection surface 20c is provided.

The reflection surface 20a is inclined at a predetermined angle with respect to the first total reflection surface 20b and the second total reflection surface 20c, and a reflection film 27 is formed on the entire surface. The reflection surface 20a reflects the image light incident on the light guide plate 20 to the first total reflection surface 20b side by the reflection film 27. Here, the reflection film 27 is formed of a metal having high light reflectivity, for example, aluminum, silver, nickel, or the like. In the present embodiment, the reflective film 27 is formed by evaporating aluminum. The reflective film 27 is not limited to this, and may be formed by sputtering a metal having high light reflectivity, transferring a metal foil, or applying a paint containing a metal thin film.
The reflection surface 20a is inclined in the range of 25 ° to 40 ° with respect to the first total reflection surface 20b in order to cause the first total reflection surface 20b to totally reflect the image light reflected by the reflection film 27.

The first total reflection surface 20 b is a surface that is parallel to the XZ plane and that is located on the viewer side (−Y side) among the surfaces that form the light guide plate 20, and the image light reflected by the reflection film 27 is the first. 2 Total reflection is performed toward the total reflection surface 20c side. Further, the first total reflection surface 20b totally reflects the image light totally reflected on the second total reflection surface 20c toward the second total reflection surface 20c side.
As for the 1st total reflection surface 20b, the edge part of the -X side becomes a light-incidence surface which injects the image light projected from the image source 11, and the edge part of + X side is unit optical shape. It is a light exit surface that emits the image light reflected by the unit 30 (described later) to the outside of the light guide plate 20.
The second total reflection surface 20c is a surface (surface on the side away from the observer side) that is parallel to the XZ plane and located on the back side (+ Y side) among the surfaces that form the light guide plate 20. The image light totally reflected on the first total reflection surface 20b is totally reflected toward the first total reflection surface 20b side.
As described above, the image light reflected by the reflection film 27 is guided in the + X direction (light guide direction) in the light guide plate 20 by repeating total reflection between the first total reflection surface 20b and the second total reflection surface 20c. It will be illuminated.

Next, the layer configuration of the light guide plate 20 will be described.
FIG. 2 is a diagram illustrating details of the light guide plate 20 of the present embodiment. FIG. 2A is a detailed view of part a in FIG. 1 and shows the layer structure of the light guide plate 20. FIG. 2B is a diagram showing details of the part b in FIG.
As shown in FIG. 2A, the light guide plate 20 includes a base material portion 21, a bonding layer 24, a second optical shape layer 23, and a first optical shape layer 22 in order from the observer side (−Y side). Has been.
The base material portion 21 is a flat member that is the basis of the light guide plate 20, and is formed of, for example, an acrylic resin, a styrene resin, an acrylic styrene resin, a polycarbonate resin, an alicyclic polyolefin resin, or the like with high light transmittance. Has been. The first total reflection surface 20b described above is a surface on the viewer side (−Y side) of the base material portion 21.

The first optical shape layer 22 is a layer located on the side of the light guide plate 20 that is farthest from the viewer side. The first optical shape layer 22 is made of a highly light transmissive urethane acrylate resin, epoxy acrylate resin, or the like, and has a refractive index equivalent to that of the base material portion 21 described above. The first optical shape layer 22 is a surface on the viewer side (−Y side), and a plurality of unit optical shape portions 30 are provided in the vicinity of the end portion on the + X side.
The unit optical shape sections 30 extend in the vertical direction (Z direction) and are arranged in a plurality along the light guide direction (X direction) of the image light. The unit optical shape section 30 is convex toward the observer side (−Y side), is parallel to the direction in which the image light is emitted (the thickness direction of the light guide plate 20, the Y direction), and has a unit optical shape. The cross-sectional shape (XY plane) parallel to the arrangement direction (X direction) of the parts 30 is formed in a substantially triangular shape, so-called prism shape. Accordingly, the unit optical shape portion 30 is provided on the first inclined surface 30a and the second inclined surface 30a provided on the side (+ X side) on which the image light travels from the first inclined surface 30a, facing the first inclined surface 30a. It is comprised from the inclined surface 30b.
The second total reflection surface 20c described above is a surface on the back side (+ Y side) of the first optical shape layer 22.

In the present embodiment, the unit optical shape portion 30 will be described as an example in which the unit optical shape portion 30 is formed in a linear prism shape extending in the vertical direction (Z direction). Alternatively, it may be formed in a circular Fresnel lens shape in which a plurality of unit optical shape portions 30 are arranged concentrically.
The first inclined surface 30a is a surface on which the image light totally reflected from the first total reflection surface 20b is directly incident, and its + X side end is closer to the observer (light emission) side than the −X side end ( -Y side). A reflective layer (semi-transmissive reflective layer) 25 is provided on the first inclined surface 30a.
The second inclined surface 30b is a surface on which the image light totally reflected by the first total reflection surface 20b does not directly enter, and the + X side end portion is closer to the back side (+ Y side) than the −X side end portion. positioned.

The second optical shape layer 23 is a layer provided on the surface of the first optical shape layer 22 on the viewer side so as to cover the unit optical shape portion 30, and the viewer side of the first optical shape layer 22 ( -Y side) is provided to flatten the surface. The second optical shape layer 23 is formed of a highly light transmissive urethane acrylate resin, epoxy acrylate resin, or the like. The surface on the observer side of the second optical shape layer 23 is a surface bonded to the base material portion 21 via the bonding layer 24, and light passing from the second optical shape layer 23 to the base material portion 21. The light exit surface. The light output surface of the second optical shape layer 23 is parallel to the first total reflection surface 20 b (light output surface) of the light guide plate 20.
The base 21 provided on the observer side of the second optical shape layer 23 may be omitted, and the surface on the observer side of the second optical shape layer 23 may be used as the light exit surface of the light guide plate 20.

Here, an angle formed by the first inclined surface 30a of the unit optical shape portion 30 and a surface (XZ plane) parallel to the first total reflection surface 20b (light-emitting surface) is α. The angle formed by the second inclined surface 30b and the surface parallel to the first total reflection surface 20b is β (β> α).
Further, the arrangement pitch of the unit optical shape portions 30 is P, and the height of the unit optical shape portions 30 (between the top t of the unit optical shape portions 30 in the thickness direction (Y direction) of the light guide plate and the unit optical shape portions 30). H) is a dimension up to a portion v that becomes the bottom of the valley. The arrangement pitch P is equivalent to the width dimension of the unit optical shape portions 30 in the arrangement direction (X direction).
In the unit optical shape section 30 of the present embodiment, the arrangement pitch P is constant, and the angle β is constant at 90 °, but gradually increases as the angle α moves toward the image light traveling side (+ X side). In addition, although an example in which the height h is increased along with this will be described, the present invention is not limited to this. For example, the arrangement pitch P, the angle α, the angle β, and the height h may be formed constant.

FIG. 3 is a diagram illustrating an example of a trajectory of external light on the second inclined surface having a unit optical shape.
Here, the first optical shape layer 22 and the second optical shape layer 23 are basically formed of the same material or the like so that the refractive indexes of both layers are equal. In some cases, a minute refractive index difference (for example, 1/1000 or less) may occur. For example, when the refractive index of the first optical shape layer is larger than the refractive index of the second optical shape layer, as shown in FIG. 3A, a part of the external light G10 transmitted through the first optical shape layer is Then, the light is totally reflected on the second inclined surface and reaches the observer side in a state slightly inclined with respect to the normal direction of the light exit surface. In addition, when the refractive index of the first optical shape layer is smaller than the refractive index of the second optical shape layer, as shown in FIG. 3B, the external environment transmitted through the first optical shape layer and the second optical shape layer A part of the light G11 is totally reflected on the second inclined surface and reaches the observer side in a state slightly inclined with respect to the normal direction of the light exit surface. In this way, when the external light reaches the observer side with a slight inclination with respect to the normal direction of the light exit surface, the slightly inclined state in the vicinity of the external light G0 emitted in the front direction. The external light G10 and the light G11 are emitted, and a double image, a so-called ghost is generated, and the external light visually recognized by the observer becomes unclear.

Therefore, the light guide plate 20 of the present embodiment is provided with a fine concavo-convex shape on the second inclined surface 30b as shown in FIG. 2B in order to solve the above-described problem of ghost generation. As described above, by providing the fine uneven shape on the second inclined surface 30b, the light incident on the second inclined surface 30b out of the external light incident from the back side of the light guide plate 20 is reflected on the second inclined surface 30b. It is possible to suppress total reflection. Thereby, the light guide plate 20 can suppress the occurrence of the above-described ghost and blurring of external light visually recognized by the observer.
As shown in FIG. 2 (b), the fine uneven shape is formed by a unit shape 31 that protrudes from the second inclined surface 30b and extends in the vertical direction (Z direction) along the second inclined surface 30b. A plurality of light guide plates 20 are arranged in the thickness direction (Y direction).

  The unit shapes 31 of the present embodiment are parallel to the arrangement direction (thickness direction of the light guide plate 20, Y direction) and in a cross section (XY plane) parallel to the arrangement direction (X direction) of the unit optical shape portions 30. The cross-sectional shape is formed in a substantially triangular shape, and includes a slope 31a and a slope 31b facing the slope 31a. In order to avoid the above-described ghost generation more efficiently, the fine uneven shape has an arrangement pitch of the unit shapes 31 as P2, a distance (height) from the bottom b to the top p of the unit shapes 31 as h2, When the aspect ratio between the height h2 and the pitch P2 is A = h2 / P2, it is desirable to satisfy the following formula (1).

  Formula (1) 0.05 <= A <= 0.5

Thus, by forming the unit optical shape part 30 so as to satisfy the above formula (1), one of the light incident on the second inclined surface 30b out of the external light incident from the back side of the light guide plate 20 is obtained. The part is diffused by the fine uneven shape, and the other part is emitted to a position away from the front of the observer without being totally reflected at the second inclined surface 30b (G2 in FIG. 4). reference). Thereby, the light guide plate 20 of the present embodiment can suppress the occurrence of the above-mentioned ghost, and can clear the outside light reaching the observer side.
If the aspect ratio A is smaller than 0.05, it is not desirable because the light from the outside is easily totally reflected on the second inclined surface 30b, and the effect of suppressing ghost generation is reduced. On the other hand, when the aspect ratio A is larger than 0.5, a part of the image light may enter the slope 31b, which is not desirable.
In addition, from the viewpoint of sufficiently suppressing the total reflection that causes the above-described ghost occurrence, the ratio of the slopes 31a and 31b of the unit shape 31 in the second slope 30b is desirably 30% or more.
Further, in the present embodiment, an example is shown in which the arrangement pitch P2 and the height h2 of the unit shapes 31 are constant. However, the present invention is not limited to this, and the arrangement pitch P2 and the height h2 are the same as those of the second inclined surface 30b. You may make it change according to a position.

Here, an angle formed by the inclined surface 31a and the normal direction of the light exit surface (XZ surface) of the light guide plate 20 is θ1, and an angle formed by the inclined surface 31b and the normal direction of the light output surface (XZ surface) of the light guide plate 20 is defined. When θ2 is set and the refractive index of the first optical shape layer 22 or the second optical shape layer 23 is n, the angle θ1 and the angle θ2 are each preferably {arcsin (1 / n)} / 2 or more. Moreover, it is more desirable that it is arcsin (1 / n) or more.
As described above, when the angle θ1 and the angle θ2 satisfy the above ranges, it is possible to more reliably suppress the external light from being totally reflected on the inclined surfaces 31a and 31b. Thereby, it is possible to suppress the external light incident from the left and right end sides (−X side end portion and + X side end portion) of the observer from reaching the front side of the observer, thereby further improving the generation of the ghost. Can be suppressed.
The unit shapes 31 of the present embodiment are formed so that the arrangement pitch P2 is 1 μm and the height h2 is 0.18 μm, that is, the aspect ratio is A = 0.18, and θ1 = θ2 = about 19.8 °. ing.

  The bonding layer 24 is an adhesive that bonds the base material portion 21 and the second optical shape layer 23 together. The bonding layer 24 is made of a material having a refractive index equivalent to those of these layers so as not to refract the image light transmitted between the base portion 21 and the second optical shape layer 23, for example, a highly light-transmitting urethane acrylate resin, It is formed of an epoxy acrylate resin, an acrylic adhesive, a silicone adhesive, or the like.

The reflective layer 25 is a so-called magic mirror (half mirror) that reflects part of incident light and transmits the other part. The ratio between the reflectance and the transmittance of the reflective layer 25 can be set as appropriate, but the transmittance is in the range of 40 to 60% from the viewpoint of favorably reflecting the image light and favorably transmitting the external light. It is desirable that The reflective layer 25 of the present embodiment is formed in a half mirror shape with both reflectance and transmittance of 50%.
The reflection layer 25 is formed on the surface of the first inclined surface 30a of the unit optical shape portion 30 with a metal having high light reflectivity, for example, aluminum, silver, nickel, or the like. In the present embodiment, the reflective layer 25 is formed by evaporating aluminum. The reflective layer 25 is not limited to this, and may be formed by sputtering a metal having high light reflectivity, transferring a metal foil, or applying a paint containing a metal thin film.

The reflective layer 25 of the present embodiment is formed to a thickness of about 100 mm by vapor deposition of aluminum. However, if the light reflectance and transmittance can be set within the above-mentioned preferable ranges, the thickness depends on the material and the like. Can be set freely.
Here, from the viewpoint of efficiently reflecting the image light and emitting the light from the light guide plate 20, the angle α of the first inclined surface 30a is within the range of 20 ° ≦ α ≦ 35 °, and the height of the unit optical shape portion 30. h is preferably formed within the range of 20 μm ≦ h ≦ 700 μm. Further, it is desirable that the arrangement pitch P of the unit optical shape portions 30 is formed within a range of 50 μm ≦ P ≦ 1000 μm.

Next, the operation of the image light L and the external light G incident on the light guide plate 20 of the present embodiment will be described.
FIG. 4 is a diagram for explaining the trajectory of external light that passes through the second inclined surface, and corresponds to FIG.
As shown in FIG. 1, the video light L emitted from the video source 11 enters the first total reflection surface 20 b of the light guide plate 20 through the projection optical system 12. The image light L that has entered the light guide plate 20 enters the reflection film 27 of the reflection surface 20a and is reflected toward the first total reflection surface 20b. Then, the image light L enters the first total reflection surface 20b and is totally reflected toward the second total reflection surface 20c, and then enters the second total reflection surface 20c and enters the first total reflection surface 20b. And totally reflected. Thus, by repeating total reflection between the first total reflection surface 20b and the second total reflection surface 20c, the video light L is guided from the −X side to the + X side of the light guide plate 20, and the first optical The light enters the unit optical shape portion 30 provided in the shape layer 22.
In the light guide plate 20 of the present embodiment, as shown in FIG. 1, the video light L is totally reflected twice on the first total reflection surface 20b and is totally reflected once on the second total reflection surface 20c. However, the present invention is not limited to this, and the total reflection may be repeated more or less on each surface.

  Of the image light incident on the unit optical shape portion 30, a part of the image light L1 is incident on the reflection layer 25 of the first inclined surface 30a as shown in FIG. 2A, and the first total reflection surface 20b. The light is reflected in a direction substantially perpendicular to (−Y direction) and emitted from the first total reflection surface 20b toward the eye E of the observer. Other image light passes through the reflection layer 25 formed in a half mirror shape and enters the unit optical shape portion 30, most of which is on the back side (+ Y of the first optical shape layer 22). To the side).

As shown in FIG. 1, the external light G enters the light guide plate 20 from the second total reflection surface 20 c on the back side (+ Y side) of the light guide plate 20. A part of the external light G that has entered the light guide plate 20 is incident on the reflective layer 25 of the first inclined surface 30 a, and a part of the light is reflected by the reflective layer 25 toward the back side of the light guide plate 20. However, as shown in FIG. 2A, the other part G1 is transmitted through the reflective layer 25 formed in a half mirror shape, and is observed from the first total reflection surface 20b (light exit surface). The light is emitted toward the eye E (front).
Further, a part of the external light incident on the second inclined surface 30b is diffused by the fine uneven shape, and most of the light does not reach the observer side. In addition, as shown in FIG. 4, the other part G2 is transmitted through the second inclined surface 30b without being totally reflected, and is located away from the front of the observer from the first total reflection surface 20b (light-emitting surface). The light is emitted toward and is not visually recognized by the observer. Further, when the refractive index of the first optical shape layer 22 is larger than that of the second optical shape layer 23, the outside world is incident on the back surface of the first optical shape layer 22 with a large incident angle with respect to the (+ Y side surface). The light G3 is totally reflected on the second inclined surface 30b (the inclined surface 31b), but it is also emitted from the first total reflecting surface 20b (the light emitting surface) toward a position away from the front of the observer, It is not visually recognized.

Next, a method for manufacturing the light guide plate 20 of the present embodiment will be described.
FIG. 5 is a diagram illustrating a method for manufacturing the light guide plate 20 of the present embodiment. Each drawing in FIG. 4 is a diagram illustrating a process until the light guide plate 20 is manufactured.
First, as shown in FIG. 5A, using a mold provided with a shape corresponding to the unit optical shape portion 30, the first optical shape layer 22 constituting the light guide plate 20 is formed by an extrusion molding method, It is formed by an injection molding method or the like.
Next, as shown in FIG. 5B, the reflective layer 25 is formed by vapor-depositing aluminum on the first inclined surface 30 a of the unit optical shape portion 30 by a vacuum vapor deposition method. The reflective layer 25 may be formed by applying a paint containing a light reflecting material.

Subsequently, as shown in FIG. 5C, the surface of the first optical shape layer 22 on the side where the unit optical shape portion 30 is formed is filled with the resin constituting the second optical shape layer 23, and the flat surface The second optical shape layer 23 is formed by, for example, releasing the mold after pressing it with a mold on which is formed.
Next, as shown in FIG. 5 (d), the second optical shape layer 23 formed on the unit optical shape portion 30 and the flat substrate portion 21 are bonded together via the bonding layer 24. Then, a laminated body in which the base material portion 21, the bonding layer 24, the second optical shape layer 23, and the first optical shape layer 22 are sequentially laminated is completed.
Finally, after cutting this laminate into a predetermined shape, the corner on the back side (−Y side) on the + X side (the side opposite to the side where the unit optical shape portion is formed) is processed. The reflective surface 20a is formed, and the reflective film 27 is formed on the reflective surface 20a by, for example, depositing aluminum by a vacuum deposition method or the like. Thus, the light guide plate 20 is completed.

As described above, since the light guide plate 20 of the present embodiment has a fine uneven shape formed on the second inclined surface 30b, it is incident on the second inclined surface 30b out of the external light incident from the back side of the light guide plate 20. It is possible to suppress the reflected light from being totally reflected at the second inclined surface 30b and to emit the light to a position away from the front of the observer. Thereby, the light guide plate 20 of the present embodiment can suppress the occurrence of a ghost in the transmitted external light, and the external light visually recognized by the observer from being blurred.
In the light guide plate 20 of the present embodiment, the arrangement pitch of the unit shapes 31 constituting the fine uneven shape is P2, the distance between the bottom b and the top p of the unit shape 31 is h2, and the aspect ratio thereof is A. = H2 / P2, 0.05 ≦ A ≦ 0.5 is satisfied. Thereby, it can suppress more efficiently that much light which injected into the 2nd inclined surface 30b will totally reflect in the 2nd inclined surface 30b, and can be made to radiate | emit to the position away from the observer's front.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made as in the modifications described later, and these are also included in the present invention. Within the technical scope. In addition, the effects described in the embodiments are merely a list of the most preferable effects resulting from the present invention, and the effects of the present invention are not limited to those described in the embodiments. It should be noted that the above-described embodiment and modifications described later can be used in appropriate combination, but detailed description thereof is omitted.

(Deformation)
FIG. 6 is a diagram illustrating a shape of a second inclined surface according to a modified embodiment. Each diagram in FIG. 6 corresponds to FIG.
FIG. 7 is a diagram for explaining a modified transflective sheet.
(1) In the above-described embodiment, the unit shape 31 constituting the fine uneven shape of the second inclined surface 30b has been described as an example in which the cross-sectional shape in a cross section parallel to the XY plane is formed in a substantially triangular shape. However, the present invention is not limited to this. For example, as shown in FIG. 6A, the unit shape 31 may be formed so that the cross-sectional shape is a wave shape (sinusoidal shape). In this case, the unit shape 31 includes a curved surface 31a and a curved surface 31b. The average angle formed by the curved surface 31a and the normal direction of the light exit surface (XZ plane) of the light guide plate 20 is θ1, and the curved surface 31b and the light guide plate 20 are formed. The average angle formed by the normal direction of the light exit surface (XZ plane) is θ2.
Further, as shown in FIG. 6B, the unit shape 31 may be formed such that the same cross-sectional shape is trapezoidal. In this case, the unit shape 31 includes a slope 31a, a slope 31b, and a flat surface 31c formed between the slopes, and the normal direction of the slope 31a and the light exit surface (XZ plane) of the light guide plate 20 is Is the angle θ1, and the angle between the inclined surface 31b and the normal direction of the light exit surface (XZ surface) of the light guide plate 20 is θ2. Even if the fine uneven unit shape 31 is formed as described above, the same effects as those of the light guide plate 20 described above can be obtained.

(2) In the above-described embodiment, the example in which the transflective reflection sheet is applied to the light guide plate 20 has been described. However, the present invention is not limited to this. For example, as shown in FIG. 7, the transflective reflection sheet is a reflection sheet 20 that directly reflects the image light from the image source 11 of the display device 1 to the viewer side on the first inclined surface 30a. It can also be applied. In this case, the angle α of the first inclined surface 30a is in the range of 5 ° ≦ α ≦ 35 °, and the height h of the unit optical shape portion 30 is in the range of 5 μm ≦ h ≦ 700 μm. The arrangement pitch P is preferably formed within a range of 50 μm ≦ P ≦ 1000 μm.
Further, it can be applied to a head-up display mounted on a front window of an automobile or the like, a screen that transmits light from the outside such as a background, and the like.
Further, when the transflective reflection sheet is applied to a large virtual image projection such as a combiner, the unit optical shape portion may be formed in a Fresnel lens shape.

(3) The angle β of the second inclined surface 30b is not limited to be perpendicular to the light exit surface (β = 90 °), but may be inclined at a predetermined angle (for example, within 2 × α). Good. By doing in this way, it can suppress that a ghost arises more efficiently, without preventing the incident light of the image light to the 1st inclined surface 30a.

(4) In the above-described embodiment, the light guide plate 20 has an example in which the first total reflection surface 20b and the surface on which the image light enters are formed in the same plane. However, the present invention is not limited to this. The first total reflection surface and the surface on which the image light enters may be formed as different surfaces.
In the above-described embodiment, the light guide plate 20 has an example in which the first total reflection surface 20b and the light exit surface from which the image light exits are formed in the same plane. However, the present invention is not limited to this. The first total reflection surface and the surface from which the image light exits may be formed as different surfaces.

DESCRIPTION OF SYMBOLS 1 Display apparatus 11 Image source 12 Projection optical system 20 Light guide plate 20a Reflective surface 20b 1st total reflection surface 20c 2nd total reflection surface 21 Base material part 22 1st optical shape layer 23 2nd optical shape layer 24 Bonding layer 25 Reflection layer 27 Reflective film 30 Unit optical shape part 30a First inclined surface 30b Second inclined surface 31 Unit shape 31a, 31b Slope E Eye of the observer

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is a transflective reflection sheet (20) that transmits external light from the back, reflects video light, and emits the video light and external light from a light exit surface. A first optical shape layer (22) in which a plurality of optical shapes (30) are arranged, and a second optical shape layer having the light exit surface and stacked on the unit optical shape side surface of the first optical shape layer (23), and the unit optical shape is a first inclined surface (30a) inclined with respect to the light exit surface, and a second slope inclined with respect to the light exit surface, facing the first inclined surface. A cross-sectional shape in a section parallel to the direction in which the image light is emitted and parallel to the arrangement direction of the unit optical shapes is formed in a substantially triangular shape, and the first inclined surface to a portion of the incident light specularly reflected, among the incident light Of which others transmitted transflective type reflective layer (25) is formed on the second inclined surface, the fine irregularities are formed, a semi-transmission type reflection sheet according to claim.
According to a second aspect of the present invention, in the transflective reflection sheet (20) according to the first aspect, the concave-convex shape is such that the unit shape (31) is along the second inclined surface (30b). When the arrangement pitch of the unit shapes is P2, the distance between the bottom and the top of the unit shapes is h2, and A = h2 / P2, 0.05 ≦ A It is a transflective reflection sheet characterized by satisfying ≦ 0.5.
A third aspect of the present invention is a display device comprising: the transflective reflection sheet (20) according to the first or second aspect; and an image source (11) that emits image light to the transflective reflection sheet. (1).

The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
The invention of claim 1 is a transflective reflection sheet (20) that transmits external light from the back, reflects video light, and emits the video light and external light from a light exit surface. A first optical shape layer (22) in which a plurality of optical shapes (30) are arranged, and a second optical shape layer having the light exit surface and stacked on the unit optical shape side surface of the first optical shape layer (23), and the unit optical shape is a first inclined surface (30a) inclined with respect to the light exit surface, and a second slope inclined with respect to the light exit surface, facing the first inclined surface. A cross-sectional shape in a section parallel to the direction in which the image light is emitted and parallel to the arrangement direction of the unit optical shapes is formed in a substantially triangular shape, and the first inclined surface only a portion of the incident light specularly reflected, light incident Other and semi-transmissive reflective layer (25) is formed for transmitting, wherein the second inclined surface is formed with fine irregularities, said irregularities, the unit shape (31) of the second A plurality of the transflective reflective sheets are arranged in the thickness direction along the inclined surface (30b), the arrangement pitch of the unit shapes is P2, the distance between the bottom and top of the unit shapes is h2, and A = A transflective reflection sheet satisfying 0.05 ≦ A ≦ 0.5 when h2 / P2 .
Invention of Claim 2 is a display apparatus (1) provided with the transflective sheet | seat (20) of Claim 1, and the image source (11) which radiate | emits image light to the said transflective sheet. is there.

Claims (3)

A transflective reflective sheet that transmits external light from the back surface and reflects video light to emit the video light and external light from a light exit surface,
A first optical shape layer in which a plurality of unit optical shapes are arranged;
A second optical shape layer having the light exit surface and laminated on the unit optical shape side surface of the first optical shape layer;
The unit optical shape includes a first inclined surface that is inclined with respect to the light exit surface, and a second inclined surface that is opposed to the first inclined surface and is inclined with respect to the light exit surface, and the image light is A cross-sectional shape in a cross section parallel to the direction of light emission and parallel to the arrangement direction of the unit optical shapes is formed in a substantially triangular shape,
The first inclined surface is formed with a transflective reflection layer that reflects a part of the image light and transmits the other part,
A fine uneven shape is formed on the second inclined surface,
A transflective reflective sheet characterized by The transflective sheet according to claim 1,
As for the uneven shape, a plurality of unit shapes are arranged in the thickness direction of the transflective sheet along the second inclined surface,
When the arrangement pitch of the unit shapes is P2, the distance between the bottom and the top of the unit shapes is h2, and A = h2 / P2,
Satisfy 0.05 ≦ A ≦ 0.5,
A transflective reflective sheet characterized by The transflective reflection sheet according to claim 1 or 2,
An image source for emitting image light to the transflective reflection sheet;
A display device comprising:

Images