JP6859655B2 - Display device - Google Patents

Description

The present invention relates to a display device that displays an image to an observer.

Conventionally, a head-mounted display device (HMD) has been proposed in which an observer observes an image from an image source such as an LCD (Liquid Crystal Display) or an organic EL display via an optical system. (For example, Patent Document 1). Such a head-mounted display device magnifies the image light projected from the image source by an optical system such as a lens and displays a clear image to the observer.
The image source used in such a display device is provided with a plurality of pixel areas constituting the image and a non-pixel area provided between the pixel areas and not contributing to the display of the image. When the image light emitted from such an image source is magnified by a lens, not only the image composed of the pixel area but also the non-image area caused by the non-pixel area is enlarged. In some cases, the non-image area may be visually recognized by the observer, which may hinder the display of a clear image.

Japanese Patent Publication No. 2011-509417

An object of the present invention is to provide a display device capable of suppressing visual recognition of a non-image region caused by a non-pixel region existing between pixels of an image source.

The present invention solves the above problems by the following solutions. In addition, in order to facilitate understanding, the description will be given with reference numerals corresponding to the embodiments of the present invention, but the present invention is not limited thereto.

The first invention is between an image source (11) that emits image light, a lens (12) that magnifies the image light and emits it to the observer side, and the image source (11) and the lens (12). , Or an optical sheet (20) arranged on the observer side of the lens (12), and the optical sheet (20) has a unit shape (21a, 23a) formed in a convex or concave shape. The unit shapes (21a, 23a) are arranged in a specific arrangement direction in the sheet surface orthogonal to at least the thickness direction of the optical sheet (20), and the image source (11) has a plurality of colors. The pixels of the same color are arranged side by side, and the direction in which the distances between the pixels of the same color are closest to each other is defined as the first proximity arrangement direction, which is a direction different from the first proximity arrangement direction. When the direction in which the pixels of the same color are close to each other next to the first proximity arrangement direction is defined as the second proximity arrangement direction, the specific arrangement direction is the first proximity arrangement direction and the second proximity arrangement direction. The display device (1) is arranged at an angle of 5 degrees or more with respect to the arrangement direction.

According to the second invention, in the display device (1) according to claim 1, the directions are different from the first proximity arrangement direction and the second proximity arrangement direction, and are the same next to the second proximity arrangement direction. The direction in which the distances between the color pixels are closest to each other is defined as the third proximity arrangement direction, which is different from the first proximity arrangement direction, the second proximity arrangement direction, and the third proximity arrangement direction. When the direction in which the distance between pixels of the same color is closest to each other next to the third proximity arrangement direction is defined as the fourth proximity arrangement direction, the specific arrangement direction is the first proximity arrangement direction and the first proximity arrangement direction. It is arranged at an angle of 6 degrees or more with respect to the two proximity arrangement directions, and the specific arrangement direction has an angle of 3 degrees or more with respect to the third proximity arrangement direction and the fourth proximity arrangement direction. It is a display device (1) characterized by being arranged.

The third invention is the display device (1) according to the first invention or the second invention, in which the optical sheet (20) is convex or concave at the first interface, which is the interface between the two layers. The first unit shape (21a) formed and the second unit shape (23a) formed convexly or concavely at the second interface, which is an interface between two layers different from the first interface. ), And the first unit shape (21a) extends in the first direction in the sheet surface orthogonal to the thickness direction of the optical sheet (20), and the first direction. The second unit shape (23a) is arranged in a second direction orthogonal to the above, and extends in a third direction in the sheet surface orthogonal to the thickness direction of the optical sheet (20). The display device (1) is arranged in a fourth direction orthogonal to the third direction, and the specific arrangement direction is the second direction and the fourth direction. ..

In the fourth invention, in the display device (1) according to the third invention, the first refractive index difference Δn1, which is the difference in the refractive indexes of adjacent layers at the first interface, is 0.005 ≦ Δn1. The fact that the second refractive index difference Δn2, which satisfies ≦ 0.1 and is the difference in the refractive indexes of the adjacent layers at the second interface, satisfies 0.005 ≦ Δn2 ≦ 0.1. This is a characteristic display device (1).

The fifth invention is the display device (1) according to any one of the first to fourth inventions, wherein the display device (1) includes a holding portion (32) for holding the optical sheet (20), and the optical At least one of the optical sheet (20) and the holding portion (32) has a positioning shape or a positioning index for defining the position of the sheet (20) in the sheet surface in the rotation direction with respect to the image source (11). It is a display device (1) characterized by being prepared for.

In the sixth invention, in the display device (1) according to any one of claims 1 to 5, the distance between the optical sheet (20) and the image source (11) is the same. The display device (1) is characterized in that it is 100 times or more the array pitch of pixels.

According to the present invention, it is possible to provide a display device capable of suppressing visual recognition of a non-image region caused by a non-pixel region existing between pixels of an image source.

It is a figure explaining the head-mounted display device 1 of this embodiment. FIG. 1 is a view of the display device 1 as viewed from above in the vertical direction. It is a figure which looked at the optical sheet 20, the holding part 32, and the image source 11 used for the display device 1 of this embodiment from the observer side (−Y side). It is a figure explaining the detail of the optical sheet 20 used for the display device 1 of this embodiment. It is a figure which shows the relationship between the brightness and the diffusion angle of the optical sheet 20 used for the display device 1 of this embodiment. It is a figure which shows the example of the image displayed by the display device 1 of this embodiment. It is a figure explaining the display device 5 of the comparative example. It is the figure which summarized the result of having evaluated the relationship between the angle θ and the color bleeding. It is a figure which shows the example of the pixel arrangement of the image source 11, and is the figure explaining the spacing of the green (G) pixel. It is a figure which shows the example of the pixel arrangement of the image source 11, and is the figure explaining the spacing of the blue (B) pixel. It is a figure explaining what kind of angle is desirable to make an angle θ. It is a figure explaining another form of an optical sheet 20. It is a figure which shows another form of the 1st unit shape 21a provided in the optical sheet 20. It is a figure explaining another embodiment of the optical sheet 20 used for the display device 1 of this embodiment. It is a figure which shows the relationship between the brightness and the diffusion angle of the optical sheet 20 of another form shown in FIG. It is a figure explaining another form of the optical sheet 20 shown in FIG. It is a figure explaining another form of the optical sheet 20 shown in FIG. It is a figure explaining another form of the optical sheet 20 shown in FIG. It is a figure explaining another form of an optical sheet 20. It is a figure explaining another form of an optical sheet 20. It is a figure explaining another embodiment of the head-mounted display device 1 of this embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. It should be noted that each of the figures shown below, including FIG. 1, is a diagram schematically shown, and the size and shape of each part are exaggerated as appropriate for easy understanding.
In the present specification, numerical values such as dimensions of each member and material names described are examples of embodiments, and the present invention is not limited to these, and may be appropriately selected and used.
In the present specification, terms that specify a shape or a geometric condition, for example, terms such as parallel and orthogonal, have the same optical function in addition to their strict meanings, and can be regarded as parallel or orthogonal. It shall also include the state having the error of.
In the present specification, the sheet surface refers to a surface of a sheet-like member that is in the plane direction of the sheet when viewed as a whole.

(Embodiment)
FIG. 1 is a diagram illustrating a head-mounted display device 1 of the present 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 in the following description, in order to facilitate understanding, the vertical direction (vertical direction) is the Z direction when the observer wears the display device 1 on the head. The horizontal direction is the X direction and the Y direction. Further, of the horizontal directions, the thickness direction of the optical sheet 20 is the Y direction, and the left-right direction orthogonal to the thickness direction is the X direction. The −Y side in the Y direction is the observer side, and the + Y side is the image source side (rear side).

FIG. 2 is a view of the optical sheet 20, the holding portion 32, and the image source 11 used in the display device 1 of the present embodiment as viewed from the observer side (−Y side).
In FIG. 2, in addition to the above-mentioned XYZ directions, SX is used as a symbol indicating a second direction rotated (tilted) by an angle θ (in the XY plane) around the Y axis. -SY (Y) -SZ is shown. The SY direction coincides with the above-mentioned Y direction. The direction of the SX-SY-SZ is provided to indicate the direction of the optical sheet 20.

FIG. 3 is a diagram illustrating details of the optical sheet 20 used in the display device 1 of the present embodiment. FIG. 3A is a cross-sectional view taken along the horizontal plane (SX-SY plane) of the optical sheet 20, and FIG. 3B is a cross-sectional view taken along the line b of FIG. 3A. 3 (c) is a diagram showing the details of the c portion of FIG. 3 (a), and FIG. 3 (d) is a diagram showing the details of the d portion of FIG. 3 (b).
FIG. 4 is a diagram showing the relationship between the brightness and the diffusion angle of the optical sheet 20 used in the display device 1 of the present embodiment.
FIG. 5 is a diagram showing an example of an image displayed by the display device 1 of the present embodiment.
FIG. 6 is a diagram illustrating a display device 5 of a comparative example. FIG. 6A is a diagram for explaining the configuration of the display device 5 of the comparative example, and is a diagram corresponding to FIG. In FIG. 6A, only the image source 51 and the lens 52 are shown as the display device 5 for easy understanding. FIG. 6B is a diagram showing an example of an image displayed by the display device 5 of the comparative example.

The display device 1 is a so-called head-mounted display (HMD) that the observer wears on his / her head and displays an image in front of the observer's eyes. As shown in FIG. 1, the head-mounted display device 1 of the present embodiment includes an image source 11, a lens 12, and an optical sheet 20 inside the housing 30, and the housing 30 is provided. By attaching the image to the head of the observer so as to be in front of the observer's eyes, the image displayed on the image source 11 can be visually recognized by the observer's eye E via the optical sheet 20 and the lens 12.
In FIG. 1, the display device 1 will be described with reference to an example in which an image is displayed to both eyes E1 and E2 of the observer, but the present invention is not limited to this, and for example, one side of the observer. It may be arranged with respect to the eye E1 and display an image with respect to the eye E1.

The housing 30 is a rectangular box-shaped housing that is horizontally long in the left-right direction, and inside the housing 30, a holding portion 31 that holds the image source 11, a holding portion 32 that holds the optical sheets 20 (20A, 20B), and a lens. A holding portion 33 for holding 12 (12A, 12B) is provided. The housing 30 can be attached to the observer's head by, for example, a belt (not shown).
The holding portion 31 is a member that holds the image source 11, is on the surface of the image source 11 on the display surface 11a side, and corresponds to the observer's eyes E (E1, E2) and lenses 12 (12A, 12B). It has an opening 311 (311A, 311B) at the position where the lens is formed. In the present embodiment, the image source 11 is detachably held by the holding unit 31 (that is, the display device 1). The image light L emitted from the image source 11 enters the lens 12 (12A, 12B) through the openings 311 (311A, 311B).

The holding portion 32 is a member that is located on the observer side (−Y side) of the holding portion 31 and the image source 11 and holds the optical sheet 20. The holding portion 32 is held by fitting the optical sheet 20 (20A, 20B) into the openings 321 (321A, 321B) provided at positions corresponding to the openings 311 (311A, 311B).

The optical sheet 20 has two orthogonal unit shapes as described later. Then, in the optical sheet 20, the arrangement direction (in other words, the extending direction) of the unit shape is the specific pixel direction (first proximity arrangement direction, second proximity arrangement direction, third proximity arrangement direction) of the pixel arrangement in the image source 11. , 4th proximity arrangement direction), arranged at an angle. The specific pixel direction will be described later, but the optical sheet 20 can be arranged so as to face the holding portion 32 in a specific arrangement direction (direction having an angle with respect to the above-mentioned specific pixel direction). The convex portion 20a as a positioning shape is fitted into the concave portion 321a as a positioning shape provided in the opening 321 of the holding portion 32.
In FIG. 2, the SX direction and the SZ direction are shown together, and this direction coincides with the arrangement direction and the extension direction of the unit shape of the optical sheet 20. In the example of FIG. 2, the optical sheet 20 is tilted (rotated) with respect to the X direction and the Y direction by an angle θ.
In the present embodiment, the outer shape of the optical sheet 20 is basically a circle as shown in FIG. 2, but for example, the shape of the optical sheet 20 is a polygonal shape, and the direction in which the optical sheet 20 is mounted (rotation in the XY plane). The position of the direction) may be specified.

The holding portion 32 and the above-mentioned holding portion 31 can be integrally moved in the Y direction, and can be fixed at a desired position in the Y direction. Therefore, the distance (position in the Y direction with respect to the lens 12) between the image source 11 and the optical sheet 20 and the lens 12 can be adjusted (focus can be adjusted) according to the visual acuity of the observer and the like. Not limited to this, the holding portion 31 and the holding portion 32 may be in a form in which the positions in the Y direction are fixed.

The holding portion 33 is a member that is located on the observer side (−Y side) of the holding portion 32 and the optical sheet 20 and holds the lens 12 (12A, 12B). The holding portion 33 has an opening 331 (331A, 331B) at a position corresponding to the optical sheet 20 (20A, 20B), and a lens 12 (12A, 12B) is placed in the opening 331 (331A, 331B). It is fitted and held.

The image source 11 is a microdisplay that emits image light L and displays an image on the display surface 11a. For example, a transmissive liquid crystal display device, a reflective liquid crystal display device, an organic EL, or the like can be used. it can. As the image source 11 of the present embodiment, for example, an organic EL display having a diagonal of 5 inches is used.
The image source 11 is held by the holding unit 31 so that the display surface 11a is on the observer side (−Y side).
In the present embodiment, the display device 1 includes one image source 11, but the display device 1 is not limited to this, and corresponds to, for example, the lenses 12A and 12B described later and the observer's eyes E1 and E2, respectively. It may be in the form of having two video sources.

The lens 12 (12A, 12B) is a convex lens that magnifies the image light L emitted from the image source 11 and emits it to the observer side. In the present embodiment, the image source 11 and the optical sheet 20 (20A, 20B) are arranged on the observer side (-Y side). The lens 12 is made of highly translucent glass or resin.
A reflection suppression layer 12a is formed on the surface of the lens 12 on the image source side (back surface side, + Y side). The antireflection layer 12a is coated with, for example, a material having a general-purpose antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), a fluorine-based optical coating agent, etc.) with a predetermined film thickness. A layer that exerts a reflection suppression function by having a moth-eye structure having a minute uneven shape formed at a pitch smaller than the wavelength of light on the surface on the incident side of light is provided as an image source of the lens 12. It may be integrally laminated on the side.

By providing such a reflection suppression layer 12a, the light incident on the lens 12 is reflected on the image source side of the lens 12 toward the optical sheet 20 side, and is reflected again on the surface of the optical sheet 20 to become stray light. This can be suppressed and the contrast and brightness of the image can be improved.
Further, the reflection suppression layer 12a may be further provided on the surface of the lens 12 on the observer side (−Y side). By further providing the reflection suppression layer 12a at this position, when the image light is emitted from the lens 12, it can be suppressed from being reflected at the interface between the lens 12 and the air and becoming stray light in the lens 12, and the contrast of the image can be suppressed. Etc. can be improved.

As shown in FIG. 1, the optical sheet 20 is arranged between the image source 11 and the lens 12. The optical sheet 20 is a light-transmitting sheet having a diffusion function that slightly diffuses the image light L emitted from the image source 11.
In this embodiment, lenses 12A and 12B and optical sheets 20A and 20B are provided corresponding to the observer's binoculars E1 and E2, respectively. However, the present invention is not limited to this, and for example, one optical sheet 20 large enough to cover the regions of the lenses 12A and 12B may be arranged on the image source side (rear side, −Y side) of the lens 12. Good. However, even when the optical sheet 20 is composed of one sheet, the optical sheet 20 can be arranged so as to face a predetermined direction (a direction having an angle with respect to the above-mentioned specific pixel direction) with respect to the holding portion 32. It is configured as follows.

As shown in FIG. 6A, the head-mounted display device 5 (hereinafter referred to as the display device 5 of the comparative example), which is mainly used conventionally, is in a form not provided with the above-mentioned optical sheet 20. There, the image light L emitted from the image source 51 was magnified by the lens 52, and the image was displayed to the observer.
A display such as an organic EL used for the image source 51 and the image source 11 has a plurality of pixel regions G1 for forming an image arranged in the display portion thereof, and does not contribute to the formation of an image between the pixel regions G1. A non-pixel region G2 is provided. Therefore, in the display device 5 of the comparative example, when the image displayed by the image light L emitted from the image source 51 is magnified through the lens 52, as shown in FIG. 6B, the pixel region G1 Not only the image F1 due to the above, but also the non-image area F2 caused by the non-pixel area G2 is enlarged. Then, the non-image area F2 is also clearly visible to the observer, which may hinder a clear image display.

On the other hand, in the display device 1 of the present embodiment, by providing the above-mentioned optical sheet 20, the image light emitted from the image source 11 is slightly diffused, and as shown in FIG. 5, the diffused image is diffused. It is possible to prevent the observer from visually recognizing the non-image region F2 caused by the non-pixel region G2 due to the light.

As shown in FIG. 3, the optical sheet 20 of the present embodiment has the reflection suppression layer 24, the first optical layer 21, the second optical layer 22, and the first optical sheet 20 in this order from the image source side (rear side, + Y (SY) side). The three optical layers 23 are laminated. The optical sheet 20 has a first interface between the first optical layer 21 and the second optical layer 22 and a second interface between the second optical layer 22 and the third optical layer 23, respectively. 21a and a plurality of second unit shapes 23a are formed.
The first optical layer 21 is located on the image source side (+ Y (SY) side) of the second optical layer 22 and the third optical layer 23 in the thickness direction (Y (SY) direction) of the optical sheet 20 and is light. It is a transparent layer. The surface of the first optical layer 21 on the image source side is formed to be substantially flat. As shown in FIG. 3A, a plurality of convex first unit shapes 21a are formed on the surface of the first optical layer 21 on the observer side (−Y (SY) side). The first unit shape 21a is convex toward the observer side (−Y (SY) side).
The first unit shape 21a extends in the first direction (SZ direction) along the surface of the first optical layer 21 on the observer side, and extends in a second direction (orthogonal to the extending direction). A plurality of them are arranged in the SX direction). The first unit shape 21a is a lenticular lens shape in which the cross-sectional shape on a plane (SX-SY plane) parallel to the SX direction and the thickness direction is formed in a substantially arc shape. Here, the substantially arcuate shape means not only a perfect circular arc but also a curved shape including a part such as an ellipse or an oval.

The third optical layer 23 is a light-transmitting layer located on the most observer side (−Y (SY) side) of the optical sheet 20. The surface of the third optical layer 23 on the observer side is a surface on which the image light transmitted through the optical sheet 20 is emitted, and is formed substantially flat. As shown in FIG. 3B, a plurality of convex second unit shapes 23a are formed on the surface of the third optical layer 23 on the image source side (+ Y (SY) side). The second unit shape 23a is convex toward the image source side (+ Y (SY) side).
The second unit shape 23a extends in the third direction (SX direction) along the surface of the third optical layer 23 on the image source side, and extends in the fourth direction (the fourth direction orthogonal to the extending direction). It is a lenticular lens shape that is arranged in a plurality of SZ directions) and has a substantially arcuate cross-sectional shape on a plane (SY-SZ plane) parallel to the SZ direction and the thickness direction.

When viewed from the thickness direction of the optical sheet 20 (normal direction of the sheet surface, Y (SY) direction), the extending direction (SX direction) of the second unit shape 23a provided on the third optical layer 23 and the first It intersects (orthogonally) the extending direction (SZ direction) of the first unit shape 21a provided on the optical layer 21.
Further, when viewed from the thickness direction of the optical sheet 20 (normal direction of the sheet surface, Y (SY) direction), the arrangement direction of the first unit shape 21a (SX direction) and the arrangement direction of the second unit shape 23a (the arrangement direction of the second unit shape 23a). (SZ direction) intersects (orthogonally).
Therefore, the first direction and the fourth direction are the same direction, and the second direction and the third direction are the same direction. However, the extending direction of the first unit shape 21a and the extending direction of the second unit shape 23a do not have to be orthogonal to each other.

The second optical layer 22 is a light-transmitting layer provided between the first optical layer 21 and the third optical layer 23. Both sides of the second optical layer 22 are arranged so that the surface of the first optical layer 21 on the first unit shape 21a side and the surface of the third optical layer 23 on the second unit shape 23a side face each other. Has been done.

In the optical sheet 20 of the present embodiment, the half-value angle α of the transmitted light incident from the surface on the image source side at an incident angle of 0 ° and emitted to the observer side satisfies 0.05 ° ≤ α ≤ 0.2 °. The diffusion angle β at which the maximum brightness of the transmitted light is 1/20 is formed so as to satisfy β ≦ 5 × α.
Here, as shown in FIG. 4, the half-value angle α of the optical sheet 20 refers to the light in the left-right direction of the screen and the top-bottom direction of the screen from the observation position of the sheet surface of the optical sheet 20 at which the brightness of light becomes the maximum value. The angle with the largest absolute value among the observation angles at which the brightness is half the maximum value. Further, the diffusion angle β is an observation in which the light brightness becomes 1/20 of the maximum value in the left-right direction of the screen and the top-down direction of the screen from the observation position of the sheet surface of the optical sheet 20 where the light brightness becomes the maximum value. The angle with the largest absolute value.
Further, the optical sheet 20 of the present embodiment has a first refractive index difference Δn1 which is a difference in refractive index between the optical layers adjacent to each other, that is, a difference in refractive index between the first optical layer 21 and the second optical layer 22. The second refractive index difference Δn2, which is the difference in refractive index between the two optical layers 22 and the third optical layer 23, satisfies 0.005 ≦ Δn1 ≦ 0.1 and 0.005 ≦ Δn2 ≦ 0.1, respectively. Is formed.

As described above, the first layer of the layers adjacent to each other with the range of the values of the half-value angle α and the diffusion angle β of the optical sheet 20 and the surface on which the first unit shape 21a and the second unit shape 23a are formed as an interface. By defining the range of the refractive index difference Δn1 and the second refractive index difference Δn2, the display device 1 of the present embodiment slightly diffuses the image light L emitted from the image source 11 in the SZ direction and the SX direction. be able to. As a result, the display device 1 displays a clear image to the observer and suppresses the non-image area F2 caused by the non-pixel area G2 of the image source 11 from becoming conspicuous due to the minute diffusion of the image light L. can do.
From the viewpoint of more effectively achieving the above-mentioned effects, it is more desirable that the diffusion angle β of the optical sheet 20 is substantially equal to or close to the half-value angle α.

If the half-value angle α is less than 0.05 °, the range in which light is diffused by the optical sheet becomes too narrow, and the effect of making the non-image region F2 caused by the non-pixel region G2 inconspicuous is weakened. This is not desirable because the non-image area F2 is easily visible to the observer. Further, when the half-value angle α is larger than 0.2 °, the diffusion range of the image light becomes too wide and the sharpness of the image is lowered, which is not desirable.
Further, if the diffusion angle β is larger than 5 × α, the diffusion range of the low-luminance video light becomes too wide, and the sharpness of the video is lowered, which is not desirable.
Further, when the first refractive index difference Δn1 and the second refractive index difference Δn2 are less than 0.005, the refractive index difference between the optical layers becomes too small, and it becomes difficult for the refraction of the image light between the optical layers to occur. This is not desirable because it does not exert a sufficient diffusion effect. Further, when the first refractive index difference Δn1 and the second refractive index difference Δn2 are larger than 0.1, the refraction of light between the optical layers becomes too large, and the image light transmitted through the optical sheet becomes unclear. It is not desirable because it will end up.

The first optical layer 21 and the third optical layer 23 are each made of a highly light-transmitting PC (polycarbonate) resin, MS (methylmethacrylate / styrene) resin, acrylic resin, or the like. Both the first optical layer 21 and the third optical layer 23 are made of the same material and have the same refractive index.
Further, the second optical layer 22 is formed of a urethane acrylate resin having high light transmittance, an ultraviolet curable resin such as an epoxy acrylate resin, or the like. In the present embodiment, the first optical layer 21 and the third optical layer are formed. It is formed with a refractive index lower than the refractive index of 23.

Further, when the cross-sectional shape of the first unit shape 21a in the SX-SY cross section is formed in an arc shape, as shown in FIG. 3C, the first unit shape formed on the first optical layer 21. When the arrangement pitch of the 21a in the second direction (SX direction) is P1 and the radius of curvature of the arcuate cross-sectional shape in the SX-SY cross section of the first unit shape 21a is R1, the first unit shape 21a Is preferably formed in the range of 0.05 ≦ P1 / R1 ≦ 1.0.
Similarly, when the cross-sectional shape of the second unit shape 23a in the SY-SZ cross section is formed in an arc shape, as shown in FIG. 3D, the second unit shape 23a is formed on the third optical layer 23. When the arrangement pitch of the unit shape 23a in the fourth direction (SZ direction) is P2 and the radius of curvature of the arcuate cross-sectional shape in the SY-SZ cross section of the second unit shape 23a is R2, the second unit The shape 23a is preferably formed in the range of 0.05 ≦ P2 / R2 ≦ 1.0.

By forming the arrangement pitches P1 and P2 and the radii of curvature R1 and R2 of the first unit shape 21a and the second unit shape 23a in the above range in this way, the display device 1 is emitted from the image source 11. The image light can be efficiently and evenly diffused slightly in the vertical direction and the SX direction.
The optical sheet 20 of the present embodiment has the same cross-sectional shape as the first unit shape 21a and the second unit shape 23a, and is formed so that P1 = P2 and R1 = R2. There is.

Further, in the present embodiment, the arrangement pitch P1 of the first unit shape 21a and the arrangement pitch P2 of the second unit shape 23a are 0.1 mm ≦ P1 ≦ 0.5 mm and 0.1 ≦ P1 ≦ 0, respectively. It is preferable to satisfy 5 mm. If the array pitches P1 and P2 are less than 0.1 mm, it becomes difficult to manufacture the first unit shape 21a and the second unit shape 23a having such dimensions, and a light diffraction phenomenon occurs. This is not preferable because the image becomes unclear due to the influence of diffracted light. Further, when the arrangement pitches P1 and P2 are larger than 0.5 mm, lines between adjacent unit shapes may be visually recognized, which is not preferable.

Further, the optical sheet 20 of the present embodiment is provided with a reflection suppression layer 24 on the image source side (back surface side, + SY side) of the first optical layer 21.
Similar to the reflection suppression layer 12a provided on the image source side of the lens 12, the reflection suppression layer 24 is, for example, a material having a general-purpose antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO)). ₂ ), a fluorine-based optical coating agent, etc.) may be provided by coating with a predetermined film thickness. Further, when the image source 11 is fixed to the display device and cannot be attached or detached, a moth-eye structure having a minute uneven shape formed at a pitch smaller than the wavelength of the light is provided on the surface on the incident side of the light. A layer that exhibits a reflection suppression function may be integrally laminated on the image source side of the optical sheet 20.

By providing the reflection suppression layer 24 on the image source side of the optical sheet 20, the light incident on the optical sheet 20 is reflected by the surface of the optical sheet 20 on the image source side and directed toward the image source 11, resulting in the brightness of the image. Can be suppressed.
Further, by providing the reflection suppression layer 24 on the image source side of the optical sheet 20, the light incident on the optical sheet 20 is reflected by the surface of the optical sheet 20 on the image source side and heads toward the image source 11, and the image source 11 It is possible to suppress stray light due to reflection on the display surface 11a of the above and improve the contrast of the image.

The reflection suppression layer 24 may be further provided on the surface of the optical sheet 20 on the observer side (−Y (SY) side). By further providing the reflection suppression layer 24 at this position, when the image light is emitted from the optical sheet 20, it can be suppressed that the image light is reflected at the interface between the optical sheet 20 and the air and becomes stray light in the optical sheet 20. The contrast of the image can be improved.
Further, a layer having a hard coat function, an antifouling function, or the like may be provided on the surface of the optical sheet 20 on the image source side (+ Y (SY) side). By providing such a layer, when the image source 11 is detachable from the housing 30, the optical sheet 20 may be damaged or dirty when the image source 11 is removed from the housing 30. Therefore, it is possible to suppress the hindrance to the visual recognition of the image.

In the display device 1 of the present embodiment, the distance D1 from the display surface 11a of the image source 11 in the Y (SY) direction to the image source side (−Y (SY) side) surface of the optical sheet 20 is the image source 11. It is 100 times or more the dimension d of the pixel arrangement pitch (when the arrangement pitch is different in a plurality of arrangement directions of the pixel area G1, the smaller arrangement pitch is used). If the distance D1 is less than 100 times the dimension d, moire due to the pixel region G1 can be visually recognized, and the non-image region due to the non-pixel region G2 can be easily observed, which is not preferable.
Generally, the arrangement pitch d of the pixels of the image source 11 used in the display device 1 is 400 to 500 ppi (pixel per inch). In the present embodiment, for example, the pixel arrangement pitch d of the image source 11 is d = 0.0508 mm (500 ppi), and the image source side (−Y (SY)) of the optical sheet 20 is from the display surface 11a of the image source 11. The distance D1 in the Y (SY) direction to the side) surface is 5.08 mm.
Therefore, in the display device 1 of the present embodiment, since the optical sheets 20 are arranged at a sufficient distance from the image source 11, moire regardless of the arrangement direction of the optical sheets 20 (regardless of the value of θ). The occurrence of is suppressed.

Further, in the display device 1 of the present embodiment, as described above, since the optical sheet 20 is located on the image source side (+ Y (SY) side) of the lens 12, the image source 11 can be attached to and detached from the housing 30. When the image source 11 is removed from the housing 30 in a certain display device 1, the lens 12 is not damaged or soiled by foreign matter such as dust or dirt that has entered the housing. Further, even when the image source side of the optical sheet 20 is contaminated with foreign matter or the like, it can be wiped off without damaging the unit shape.
Further, in particular, the reflection suppression layer having a moth-eye structure has a high reflection suppression effect, but it is easily damaged, so it is important to provide it at a position where the observer's finger or the like does not touch. In the display device 1 of the present embodiment, since the optical sheet 20 is located on the image source side (+ Y (SY) side) of the lens 12, such a reflection suppression layer is provided on the observer side of the optical sheet 20 or on the lens 12. It can be provided on the image source side or the like, a higher reflection suppression effect can be obtained, and the contrast and brightness of the image can be improved.

Next, the operation until the image light L emitted from the image source 11 reaches the observer's eyes E (E1, E2) will be described.
As shown in FIG. 1, the image light L emitted from the image source 11 is incident on the surface of the optical sheet 20 (20A, 20B) on the image source side (+ Y (SY) side). Then, the image light L incident on the optical sheet 20 is transmitted through the first optical layer 21 and is formed by the first unit shape 21a of the first interface between the first optical layer 21 and the second optical layer 22. , It diffuses slightly in the second direction (SX direction) and transmits through the second optical layer 22.
The image light L transmitted through the second optical layer 22 has a fourth direction (SZ) due to the second unit shape 23a formed at the second interface between the second optical layer 22 and the third optical layer 23. It diffuses slightly in the direction), passes through the third optical layer 23, and exits from the surface of the optical sheet 20 on the observer side (−Y (SY) side).
The image light L transmitted through the optical sheet 20 is incident on the lenses 12 (12A, 12B). Then, the image light L is magnified by the lens 12 and emitted to the observer side (−Y (SY) side).

The image light L is slightly diffused by the optical sheet 20 in the second direction (SX direction) and the fourth direction (SZ direction). Therefore, even if the image is magnified by the lens 12, the image visually recognized by the observer's eye E is as shown in FIG. 5 as compared with the case of the display device 5 of the comparative example (see FIG. 6B). ), The non-image region F2 caused by the non-pixel region G2 of the image source 11 can be suppressed as much as possible, and a clear image can be displayed.
Moreover, as described above, since a sufficient distance D1 is provided between the image source 11 and the optical sheet 20, the non-image area F2 is conspicuously observed by appropriately diffusing the image light. And the occurrence of moire and the like due to the pixel region G1 and the non-pixel region G2 can be sufficiently suppressed.

Here, the arrangement of the optical sheet 20 with respect to the image source 11 in the rotation direction in the SX-SZ plane will be described.
As described above, the pixels are arranged at intervals, and the optical sheet 20 diffuses the image light so as to make the spaced portions inconspicuous. As shown in FIG. 2, in the present embodiment, the SX-SZ direction of the optical sheet 20 is tilted by an angle θ with respect to the X-Z direction of the image source 11. In many cases, this angle θ is 0 degrees, that is, a good image can be observed without tilting the optical sheet 20 with respect to the image source 11. However, many types of image sources 11 are assumed, and many types of specific shapes of the optical sheet 20 can be produced. Further, the design of the arrangement position of the optical sheet 20 can be changed as appropriate. In many of these combinations, the optical sheet 20 may cause slight color bleeding in the magnified image. As a result of research, it was found that this is mainly due to the fact that the light from pixels of different emission colors adjacent to each other is mixed and observed as another color.

As a result of various studies on techniques for eliminating this color bleeding, it was concluded that it is effective to arrange the optical sheet 20 at an angle with respect to the image source 11 as shown in FIG. By arranging the optical sheet 20 at an angle with respect to the image source 11, the diffusion direction of the optical sheet 20 does not match the arrangement direction of each pixel of the image source 11, color mixing is suppressed, and color bleeding can be eliminated. ..

FIG. 7 is a diagram summarizing the results of evaluating the relationship between the angle θ and the color bleeding.
The result of FIG. 7 is a result of actually observing the color bleeding by arranging the optical sheet 20 by gradually changing the angle θ shown in FIG. 2 of the present embodiment. The evaluation was carried out by actually visually observing the image source 11 in a state where the image source 11 was made to emit light so as to be originally white. From this result, it can be seen that it is desirable to arrange the optical sheet 20 so that θ is in the range of 5 to 40 degrees. Further, it can be seen that it is more desirable to arrange the optical sheet 20 so that θ is in the range of 10 degrees to 15 degrees and 30 degrees to 35 degrees.

Then, as a result of further study on which direction the optical sheet 20 should be arranged effectively, the distance between pixels of the same color and the direction thereof are one of the important parameters in the pixel arrangement. There was found. Specifically, the closer the distance between the pixels of the same color is, the more the color bleeding is affected. Therefore, the orientations are specified in the order of the closer distance between the pixels of the same color.

FIG. 8 is a diagram showing an example of the pixel arrangement of the image source 11, and is a diagram for explaining the spacing between the green (G) pixels.
A liquid crystal display or an organic EL display usually has a display area in which a large number of pixels of each color of red (R), green (G), and blue (B) are arranged. The example of this embodiment shown in FIG. 8 is the case of an organic EL display having a Pentile arrangement. In FIG. 8, the pixels of each color of red (R), green (G), and blue (B) are represented by circles with the letters R, G, and B, respectively. In the Pentile array, the number of greens (G) is twice the number of reds (R) and blues (B).

In the present embodiment, since more green (G) is arranged than other colors, the distance between the green (G) pixels is the closest.
In FIG. 8, a two-dot chain line shows a circle centered on a certain green (G) pixel and having a radius from that point to another green (G) pixel. In addition, the angle formed by the straight line extending from the centered pixel to the other green (G) pixel in the X direction is also shown.
Referring to FIG. 8, the closest distance between pixels of the same color is in the direction of the distance Q1, and the angle formed by the X direction is the direction of 0 degrees. This direction is defined as the first proximity arrangement direction. The direction of this distance Q1 also exists in the direction rotated by 90 degrees.
Further, when the direction different from the first proximity arrangement direction and the distance between the pixels of the same color is close to each other next to the first proximity arrangement direction is defined as the second proximity arrangement direction, this is defined as the second proximity arrangement direction. It is the direction of the distance Q2, and the angle formed by the X direction is the direction of 45 degrees.
Further, a direction different from the first proximity arrangement direction and the second proximity arrangement direction, and the direction in which the distance between pixels of the same color is closest to each other next to the second proximity arrangement direction is defined as the third proximity arrangement direction. When specified, this is the direction of Q3, and the angle formed by the X direction is the direction of 26.6 degrees.

Further, a direction different from the first proximity arrangement direction, the second proximity arrangement direction, and the third proximity arrangement direction, and the direction in which the pixels of the same color are closest to each other next to the third proximity arrangement direction. When defined as the fourth proximity arrangement direction, this relates to the red (R) and blue (B) pixels.
FIG. 9 is a diagram showing an example of the pixel arrangement of the image source 11, and is a diagram for explaining the spacing between the blue (B) pixels.
The fourth proximity arrangement direction is the direction of Q4 shown in FIG. 9, and the angle formed with the X direction is the direction of 18.4 degrees.
The second proximity arrangement direction (Q2), the third proximity arrangement direction (Q3), and the fourth proximity arrangement direction (Q4) are the same in the direction rotated by 90 degrees as in the first proximity arrangement direction. Exists in.

The above-mentioned first proximity arrangement direction (angle from X direction = 0 degrees), second proximity arrangement direction (angle from X direction = 45 degrees), third proximity arrangement direction (angle from X direction = 18.4 degrees). ), The second direction of the first unit shape 21a and the fourth direction of the second unit shape 23a with respect to each of the directions of the fourth proximity arrangement direction (angle from the X direction = 26.6 degrees). Is arranged at an angle, which is desirable to prevent color bleeding.
FIG. 10 is a diagram for explaining what kind of angle is desirable for the angle θ.
The upper part of FIG. 10 shows the evaluation result of FIG. 7 above corresponding to the angle scale below it. Further, in the lower part of FIG. 10, the above-mentioned first to fourth proximity arrangement directions are shown corresponding to the above angle scales.

(Condition 1)
First, the result of visual evaluation is not very good in the vicinity of the first proximity arrangement direction and the second proximity arrangement direction. Then, at the angular positions separated from the first proximity arrangement direction and the second proximity arrangement direction by 5 degrees, the evaluation result is Δ, and a reasonable result is obtained. Therefore, it can be said that it is desirable to set θ at an angle separated from the first proximity arrangement direction and the second proximity arrangement direction by 5 degrees or more. Therefore, θ is preferably in the range of 5 to 40 degrees.
This can be rewritten in relation to the first proximity arrangement direction and the second proximity arrangement direction as follows.
The second direction (SX direction) of the first unit shape 21a and the fourth direction (SZ direction) of the second unit shape 23a are 5 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction. It is preferable to arrange them at an angle of.

(Condition 2)
Further, in the angle range close to the third proximity arrangement direction and the fourth proximity arrangement direction, the result of visual evaluation is unfavorable, and it can be seen that it is not good to set θ at an angle close to these. Further, under the above condition 1, even at the allowable angle positions of 5 degrees and 40 degrees, some color bleeding occurs, so it is considered desirable to have a little more margin in this part as well.
Therefore, as a more preferable range from FIG. 10, a range of 6 degrees to 15.4 degrees and a range of 29.6 degrees to 39 degrees can be set.
This can be rewritten in relation to the first to fourth proximity array directions as follows.
The second direction (SX direction) of the first unit shape 21a and the fourth direction (SZ direction) of the second unit shape 23a are 6 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction. The second direction (SX direction) of the first unit shape 21a and the fourth direction (SZ direction) of the second unit shape 23a are arranged in the third proximity arrangement direction. And, it is preferable that they are arranged at an angle of 3 degrees or more with respect to the fourth proximity arrangement direction.

With such an arrangement, the display device 1 of the present embodiment can display a better image with less color bleeding or no color bleeding.

Next, a method of manufacturing the optical sheet 20 used in the display device 1 of the present embodiment will be described.
As described above, since the first unit shape 21a and the second unit shape 23a provided on the first optical layer 21 and the third optical layer 23 of the optical sheet 20 are formed in the same shape, first, first. Using a mold provided with a concave shape corresponding to this convex unit shape, a sheet-shaped member having a unit shape formed is formed by an extrusion molding method, an injection molding method, or the like.
Then, the sheet-shaped member having the unit shape formed is cut into predetermined dimensions to obtain the first optical layer 21 and the third optical layer 23.
In this way, when the first unit shape 21a and the second unit shape 23a are formed in the same shape, the first optical layer 21 and the third optical layer 23 can be simultaneously cut out from one sheet-shaped member. It is possible to improve the manufacturing efficiency of the optical sheet 20.

Subsequently, the surface of the first optical layer 21 on the side of the first unit shape 21a is filled with the resin forming the second optical layer 22, and the resin and the second unit shape 23a of the third optical layer 23 are filled. The side surface is bonded to each other, and the resin is cured with a predetermined distance between the first optical layer 21 and the third optical layer 23. At this time, the first optical layer 21 and the third optical layer 23 are arranged so that the extending direction of the first unit shape 21a and the extending direction of the second unit shape 23a intersect (orthogonally) with each other. Orthogonal.
As a result, the first optical layer 21, the second optical layer 22, and the third optical layer 23 are sequentially laminated. Further, the optical sheet 20 is completed by providing the reflection suppression layer 24 on the surface of the first optical layer 21 (the surface opposite to the second optical layer 22 side).

From the above, the display device 1 of the present embodiment has at least two or more optical layers between the image source 11 and the lens 12, and has a first unit shape 21a and a second unit shape 21a at the interface between the optical layers. The optical sheet 20 in which a plurality of unit shapes 23a are formed is provided. Further, the first refractive index difference Δn1 and the second refractive index difference Δn2 of the adjacent optical layers in which the first unit shape 21a and the second unit shape 23a are formed at the interface are 0.005 ≦ Δn1 ≦, respectively. 0.1, 0.005 ≦ Δn2 ≦ 0.1 is satisfied. Further, the distance D1 from the display surface 11a of the image source 11 to the image source side (+ Y (SY) side) surface of the optical sheet 20 is 100 times or more the arrangement pitch d of the pixel region G1. As a result, the display device 1 can slightly diffuse the image light L emitted from the image source 11, display a clear image to the observer, and the non-pixel region G2 of the image source 11 is the cause. It is possible to prevent the image area F2 from being visually recognized by the observer.

Further, in the display device 1 of the present embodiment, as described above, the optical sheet 20 is located on the image source side (+ Y (SY) side) of the lens 12. Therefore, even if the image source 11 is removed from the display device 1 (housing 30), the lens 12 can be protected from foreign matter such as invading dust and dirt, and the lens 12 is damaged by the foreign matter. It does not get dirty or dirty. Further, even when the surface of the optical sheet 20 on the image source side becomes dirty or cloudy, it can be wiped off without damaging the unit shape.
Further, in the display device 1 of the present embodiment, the image source 11 and the optical sheet 20 can be integrally moved in the Y (SY) direction, and the image source can be adjusted in the Y (SY) direction for focusing adjustment and the like. Even when the 11 is moved, it can be moved in the Y (SY) direction while keeping the distance D1 between the image source 11 and the optical sheet 20 constant. Therefore, the focus adjustment work can be performed while maintaining the diffusion effect of the optical sheet 20 that suppresses the non-image region F2 caused by the non-pixel region G2 from being visually recognized by the observer.
Further, the display device 1 of the present embodiment is provided with a reflection suppression layer 24 on the image source side (light entry side, + Y (SY) side) of the optical sheet 20, and reflection suppression is performed on the image source side surface of the lens 12. Since the layer 12a is provided, stray light can be suppressed and the brightness and contrast of the image can be improved.

Further, in the display device 1 of the present embodiment, the first unit shape 21a is convex and is inside the sheet surface (SX-SZ surface) orthogonal to the thickness direction (Y (SY) direction) of the optical sheet 20. Extends in the SZ direction (first direction), is arranged in the SX direction (second direction) orthogonal to the SZ direction in the sheet surface, and has a cross section (SX) parallel to the thickness direction and the arrangement direction of the optical sheet 20. The cross-sectional shape on the −SY surface) is formed in a substantially arc shape. Similarly, the second unit shape 23a is convex and extends in the SX direction in the sheet plane (SX-SZ plane) orthogonal to the thickness direction (Y (SY) direction) of the optical sheet 20. The optical sheet 20 is arranged in the SZ direction orthogonal to the SX direction in the sheet surface, and the cross-sectional shape in the cross section (SY-SZ surface) parallel to the thickness direction and the arrangement direction of the optical sheet 20 is formed in an arc shape. As a result, the display device 1 can efficiently and evenly diffuse the image light passing through the first unit shape 21a and the second unit shape 23a.

Further, in the display device 1 of the present embodiment, the half-value angle α of the transmitted light incident on the optical sheet 20 at an incident angle of 0 satisfies 0.05 ° ≦ α ≦ 0.2 °, and the maximum brightness becomes 1/20. The diffusion angle β of the optical sheet 20 is formed so as to satisfy β ≦ 5 × α. As a result, the image light L emitted from the image source 11 can be slightly diffused to display a clear image to the observer, and the non-image area F2 caused by the non-pixel area G2 of the image source 11 is observed. It is possible to enhance the effect of suppressing being visually recognized by a person.

Further, in the display device 1 of the present embodiment, the optical sheet 20 has three or more optical layers, and the first unit shape 21a and the second unit shape provided at each interface between adjacent optical layers are provided. The extending directions (Z direction, X direction) in the sheet surface of 23a are orthogonal (intersect) when viewed from the thickness direction of the optical sheet 20. As a result, the display device 1 can diffuse the video light emitted from the video source 11 in a plurality of directions, and more effectively make the non-video region caused by the non-pixel region of the video source 11 inconspicuous. Can be done.

Further, in the display device 1 of the present embodiment, with respect to the optical sheet 20, the second direction (SX direction) of the first unit shape 21a and the fourth direction (SZ direction) of the second unit shape 23a are the first. They are arranged at an angle of 5 degrees or more with respect to the 1-proximity arrangement direction and the 2nd proximity arrangement direction.
Further, in the display device 1 of the present embodiment, with respect to the optical sheet 20, the second direction (SX direction) of the first unit shape 21a and the fourth direction (SZ direction) of the second unit shape 23a are the first. It is arranged at an angle of 6 degrees or more with respect to the 1 proximity arrangement direction and the 2nd proximity arrangement direction, and is arranged in the second direction (SX direction) of the first unit shape 21a and the second unit shape 23a. The fourth direction (SZ direction) is arranged at an angle of 3 degrees or more with respect to the third proximity arrangement direction and the fourth proximity arrangement direction.
With such an arrangement, the display device 1 of the present embodiment suppresses that the non-image area caused by the non-pixel area existing between the pixels of the image source is visually recognized, and also causes color bleeding. It is possible to display a better image without.

It should be noted that the first unit shape 21a of the first optical layer 21 and the second unit shape 23a of the third optical layer 23 are arranged in each arrangement direction, each arrangement direction, and a cross section along the thickness direction of the optical sheet 20. The cross-sectional shapes of the unit shape 21a of 1 and the second unit shape 23a are not limited to the above examples, and may be changed as appropriate.
Hereinafter, other embodiments of the optical sheet 20 used in the display device 1 of the present embodiment will be described.

FIG. 11 is a diagram illustrating another form of the optical sheet 20. FIG. 11 (a) is a cross-sectional view in a cross section (SX-SY cross section) parallel to the thickness direction (Y (SY) direction) and parallel to the SX direction, and FIG. 11 (b) is a cross-sectional view in the thickness direction (Y (SY) direction). It is sectional drawing in the cross section (SY-SZ cross section) parallel to the Y (SY) direction) and parallel to the SZ direction.
The optical sheet 20 shown in FIG. 3 has a first unit shape 21a and a second unit shape 23a having a substantially arcuate cross-sectional shape, but the optical sheet 20 is not limited thereto.

For example, the first unit shape 21a and the second unit shape 23a are formed so that the cross-sectional shape is substantially triangular, that is, a so-called prism shape, as shown in FIG. Here, the substantially triangular shape is not only a triangular shape including an isosceles triangle or an equilateral triangle, but also a shape in which the top of the triangular shape is chamfered to a curved surface or a plane, or a triangular slope is slightly curved. It also includes the shape and the like.

Even if the optical sheet 20 is in such a form, the image light emitted from the image source 11 is slightly diffused as in the above-described embodiment, and as shown in FIG. 4, the diffused image light causes non-pixels. It is possible to prevent the non-video region F2 caused by the region G2 from being visually recognized by the observer.
Further, by setting the orientation in which the optical sheet 20 is arranged so that the value of the angle θ described above is within an appropriate range, color bleeding can be prevented.

FIG. 12 is a diagram showing another form of the first unit shape 21a provided on the optical sheet 20. Each figure of FIG. 12 corresponds to an enlarged view of part a of FIG. 11A, but the shape of the first unit shape 21a is different from that of FIG. FIG. 12 illustrates another form of the first unit shape 21a of the first optical layer 21, but the same applies to the second unit shape 23a of the third optical layer 23.
For example, as shown in FIG. 12 (a), the triangular top in the same cross section may be formed by the curved surface S1, or as shown in FIG. 12 (b), the triangular top may be a flat surface S2. It may be a form formed by.
Further, as shown in FIG. 12 (c), the triangular slope in the same cross section may be formed by curved surfaces S3 and S4 that are slightly curved instead of a flat surface.
An optical sheet having each unit shape as described above can have the same effect as the optical sheet shown in FIG.

FIG. 13 is a diagram illustrating another embodiment of the optical sheet 20 used in the display device 1 of the present embodiment. 13 (a) is a cross-sectional view taken along the horizontal plane (SX-SY plane) of the optical sheet 20, and FIG. 13 (b) is a cross-sectional view taken along the line b of FIG. 13 (a). 13 (c) is a diagram showing the details of the c portion of FIG. 13 (a), and FIG. 13 (d) is a diagram showing the details of the d portion of FIG. 13 (b).
In the optical sheet 20 shown in FIG. 13, a plurality of convex first unit shapes 21a are formed at the interface between the first optical layer 21 and the second optical layer 22, and the interface between the second optical layer 22 and the third optical layer 23 is formed. A plurality of convex second unit shapes 23a are formed on the surface.

As shown in FIG. 13A, the first unit shape 21a and the flat portion 21b are alternately provided on the surface of the first optical layer 21 on the observer side (−Y (SY) side). .. The first unit shape 21a and the flat portion 21b extend in the SZ direction along the surface of the first optical layer 21 on the observer side, and are arranged in a plurality in the SX direction.
Further, as shown in FIG. 13B, a plurality of second unit shapes 23a and flat portions 23b are alternately formed on the surface of the third optical layer 23 on the image source side (+ Y (SY) side). There is. The second unit shape 23a and the flat portion 23b extend in the SX direction along the surface of the third optical layer 23 on the image source side, and are arranged in a plurality in the SZ direction.
The second unit shape 23a and the flat portion 23b provided on the third optical layer 23 have their extending direction (SX direction) flat as the first unit shape 21a provided on the first optical layer 21 described above. It intersects (orthogonally) the extending direction (SZ direction) of the portion 21b.

In the optical sheet 20 of the other form shown in FIG. 13, the first unit shape 21a is, as shown in FIG. 13 (c), the surface (−Y (SY) side) of the first optical layer 21 on the observer side. It is formed so as to be convex from the surface) and have a substantially arcuate cross-sectional shape in the SX-SY cross section. Here, the substantially arcuate shape means not only a perfect circular arc but also a curved shape including a part such as an ellipse or an oval.
In the optical sheet 20 shown in FIG. 13, the first unit shape 21a is formed in an arc shape, the radius of curvature thereof is R1, and the width dimension in the SX direction is W1. The arrangement pitch of the first unit shape 21a (flat portion 21b) in the SX direction is P1.

Similarly, as shown in FIG. 13D, the second unit shape 23a is convex from the image source side surface (+ Y (SY) side surface) of the third optical layer 23, and is in the SY-SZ cross section. The cross-sectional shape is formed in a substantially arc shape. In the optical sheet 20 shown in FIG. 13, the second unit shape 23a is formed in an arc shape, the radius of curvature thereof is R2, and the width dimension in the SZ direction is W2. The arrangement pitch of the second unit shape 23a (flat portion 23b) in the SZ direction is P2.
Further, each unit shape and each flat portion provided on the first optical layer 21 and the third optical layer 23 are formed to have the same dimensions, for example, W1 = W2 = 0.1 mm, P1 = P2 =. It is 0.24 mm and R1 = R2 = 0.5 mm.

In the optical sheet 20 shown in FIG. 13, the arrangement pitch P1 of the first unit shape 21a and the arrangement pitch P2 of the second unit shape 23a are 0.1 mm ≦ P1 ≦ 0.5 mm and 0.1 mm ≦ P2 ≦ 0. It is preferable to satisfy 5 mm.
If the arrangement pitches P1 and P2 are less than 0.1 mm, the arrangement intervals of the unit shapes become too fine, the influence of the diffracted light becomes large, and the image becomes unclear, which is not desirable. In addition, it becomes difficult to manufacture a unit shape.
Further, if P1 and P2 are larger than 0.5 mm, the arrangement interval of the first unit shape 21a and the second unit shape 23a becomes too coarse, and the non-image area F2 is easily visible to the observer. Therefore, it is not desirable.
Further, in the optical sheet 20 shown in FIG. 13, the first refractive index difference Δn1 between the first optical layer 21 and the second optical layer 22 and the second refractive index between the second optical layer 22 and the third optical layer 23 The difference Δn2 is preferably in the same range as in the above-described embodiment.

The optical sheet 20 shown in FIG. 12 is emitted from the image source 11, and among the light incident from the surface of the optical sheet 20 on the image source side, the light transmitted through the flat portion 21b and the flat portion 23b is directly emitted to the observer side. At the same time, the light incident on the first unit shape 21a can be diffused in the SX direction, and the light incident on the second unit shape 23a can be diffused in the SZ direction and emitted to the lens 12 side.
As a result, the display device 1 displays a clear image to the observer and suppresses the non-image area F2 caused by the non-pixel area G2 of the image source 11 from becoming conspicuous due to the minute diffusion of the image light. can do. In particular, since the light transmitted through the flat portion 21b and the flat portion 23b is hardly diffused, the image light reaching the observer can be displayed more clearly by adopting such a form.
Further, by setting the orientation in which the optical sheet 20 is arranged so that the value of the angle θ described above is within an appropriate range, color bleeding can be prevented.

FIG. 14 is a diagram showing the relationship between the brightness and the diffusion angle of the optical sheet 20 of another form shown in FIG.
In order to effectively achieve the above-mentioned effect, as shown in FIG. 14A, the optical sheet 20 shown in FIG. 13 is a transmitted light incident from the image source side at an incident angle of 0 ° and emitted from the observer side. In the range where the diffusion angle in the SX direction and the SZ direction is −0.1 ° or more and 0.1 ° or less, the brightness of the light is close to the maximum brightness and the diffusion angle is 0.1 ° or more and 0.3. It is formed so as to maintain a predetermined brightness even in the range of ° or less and −0.3 ° or more and −0.1 ° or less.
Specifically, the amount of transmitted light in the range where the diffusion angles in the SX direction and the SZ direction are −0.1 ° or more and 0.1 ° or less is 30% or more of the total amount of transmitted light transmitted through the optical sheet 20, respectively. The amount of transmitted light in the range where the diffusion angles in the SX direction and the SZ direction are −0.3 ° or more and 0.3 ° or less is formed so as to be 95% or more of the total amount of transmitted light transmitted through the optical sheet 20, respectively.

Further, the amount of transmitted light in the range where the diffusion angles of the optical sheet 20 shown in FIG. 13 in the SX direction and the SZ direction are 0.1 ° or more and 0.3 ° or less is 20% or more of the total amount of transmitted light transmitted through the optical sheet 20. The amount of transmitted light in the range of the diffusion angle of −0.3 ° or more and −0.1 ° or less is formed so as to be 20% or more of the total amount of transmitted light transmitted through the optical sheet 20.
Here, the diffusion angle of the optical sheet 20 means an observation angle in the SX direction and the SZ direction from the observation position of the sheet surface of the optical sheet 20 at which the brightness of light is the maximum value.

In this way, by defining the amount of transmitted light in the range of the specific diffusion angle of the optical sheet 20 shown in FIG. 13, the display device 1 of the present embodiment has the flat portion 21b of the image light emitted from the image source 11. , The light incident on the 23b can be transmitted with almost no diffusion, and the light incident on the first unit shape 21a and the second unit shape 23a can be slightly diffused in the SZ direction and the SX direction.
As a result, the display device 1 displays a clear image to the observer and suppresses the non-image area F2 caused by the non-pixel area G2 of the image source 11 from becoming conspicuous due to the minute diffusion of the image light. be able to. In particular, since the light transmitted through the flat portions 21b and 23b is hardly diffused, by using such an optical sheet 20, a clearer image can be delivered to the observer, and the image is blurred. It can be suppressed as much as possible.

If the amount of transmitted light when the diffusion angle is −0.1 ° or more and 0.1 ° or less is less than 30% of the total amount of transmitted light transmitted through the optical sheet 20 shown in FIG. 13, the amount of light reaching the observer side is small. It is not desirable because it becomes too sharp, the image becomes unclear, and it becomes blurry.
Further, when the amount of transmitted light when the diffusion angle is −0.3 ° or more and 0.3 ° or less is less than 95% of the total amount of transmitted light transmitted through the optical sheet 20 shown in FIG. 13, the amount of light of the image reaching the observer side. It is not desirable because the number of images becomes too small and the image becomes dark.
Further, the amount of transmitted light when the diffusion angle is 0.1 ° or more and 0.3 ° or less and the amount of transmitted light when the diffusion angle is −0.3 ° or more and −0.1 ° or less are the optical sheet 20 shown in FIG. When it is less than 20% of the total amount of transmitted light transmitted, the minute diffusion of the image light by the first unit shape 21a and the second unit shape 23a becomes too small, which is caused by the non-pixel region G2 of the image source 11. This is not desirable because the non-image area F2 becomes conspicuous.

Further, in the optical sheet 20 of another form shown in FIG. 13, the amount of transmitted light in the range where the diffusion angle of the optical sheet 20 in the SX direction and the SZ direction is −0.1 ° or more and 0.1 ° or less is different from that of the optical sheet 20. The amount of transmitted light in the range of 30% or more of the total amount of transmitted light and the diffusion angle of 0.5 × sin ^-1 (d / D2) or more and 5 × sin ^-1 (d / D2) or less is the total amount of transmitted light. The amount of transmitted light in the range of -5 x sin ^-1 (d / D2) or more and -0.5 x sin ^-1 (d / D2) or less is 20% of the total transmitted light amount. Even in the above cases, the same effect as described above can be obtained.
That is, the display device 1 can slightly diffuse the image light emitted from the image source 11 in the SZ direction and the SX direction, display a clear image with less blurring to the observer, and the non-pixels of the image source 11. It is possible to prevent the non-video region F2 caused by the region G2 from being visually recognized by the observer. Further, the range of a specific diffusion angle can be appropriately defined according to the specifications of the display device 1 (the pixel arrangement pitch d and the distance D2 between the observer's eye E and the display surface 11a). It is possible to efficiently display a clear image and suppress the visual recognition of the non-image area F2.
Further, by setting the orientation in which the optical sheet 20 is arranged so that the value of the angle θ described above is within an appropriate range, color bleeding can be prevented.

15, 16 and 17 are views for explaining another form of the optical sheet 20 shown in FIG. 15 (a), 16 (a), and 17 (a) are views corresponding to FIG. 13 (a), respectively, and FIGS. 15 (b), 16 (b), and 17 (b), respectively. ) Are diagrams corresponding to FIG. 13 (b), respectively.
In the optical sheet 20 of the other form shown in FIG. 13, the first unit shape 21a is, for example, from the surface of the first optical layer 21 on the observer side (−Y (SY) side) as shown in FIG. It becomes convex, the cross-sectional shape in the SX-SY cross section is formed into a triangular shape, and the second unit shape 23a becomes convex from the image source side (+ Y (SY) side) surface of the third optical layer 23, and becomes SY-SYZ. The cross-sectional shape of the cross section may be triangular.

Further, the first unit shape 21a and the second unit shape 23a may be concave instead of convex.
For example, as shown in FIG. 16, the first unit shape 21a is a concave shape recessed from the observer side (-Y (SY) side) surface of the first optical layer 21, and is a cross section thereof in the SX-SY cross section. The shape may be such that two convex surfaces formed in an arc shape face each other in the SX direction.
Similarly, the second unit shape 23a is a concave shape recessed from the image source side (+ Y (SY) side) surface of the third optical layer 23, and the cross-sectional shape in the SX-SY cross section is formed in an arc shape. The two convex surfaces may face each other in the SZ direction.

Further, as shown in FIG. 17, the cross-sectional shape in the SX-SY cross section is triangular, and is concave from the observer side surface (-Y (SY) side surface) of the first optical layer 21. The first unit shape 21a and the cross-sectional shape in the SY-SZ cross section are triangular and concave from the image source side surface (+ Y (SY) side surface) of the third optical layer 23. The unit shape 23a may be provided.
Even in the convex or concave form as described above, the display device 1 displays the light emitted from the image source 11 to the observer side without diffusing the light transmitted through the flat portion 21b and the flat portion 23b. At the same time, the light incident on the first unit shape 21a is slightly diffused in the SX direction, and the light incident on the second unit shape 23a is slightly diffused in the SZ direction and emitted to the observer side. be able to.
As a result, the display device 1 displays a clear image with less blurring to the observer, and the non-image area F2 caused by the non-pixel area G2 of the image source 11 is conspicuously observed due to the minute diffusion of the image light. Can be suppressed.
Further, by setting the orientation in which the optical sheet 20 is arranged so that the value of the angle θ described above is within an appropriate range, color bleeding can be prevented.

FIG. 18 is a diagram illustrating another form of the optical sheet 20. FIG. 18A is a cross-sectional view in a cross section (SX-SY cross section) parallel to the thickness direction (Y (SY) direction) and parallel to the left-right direction (SX direction), and FIG. 18B is a cross-sectional view. , Is a cross-sectional view in a cross section (SY-SZ cross section) parallel to the thickness direction (SY direction) and parallel to the vertical direction (SZ direction). FIG. 18C is a perspective view of the first optical layer 21 as viewed from the observer side (−Y (SY) side).
As shown in FIG. 18, the optical sheet 20 has a form composed of two layers, a first optical layer 21 and a second optical layer 22, and is an observer side (−Y (SY) side) of the first optical layer 21. A plurality of unit shapes 21a having a substantially quadrangular pyramid shape may be arranged in the vertical direction and the left-right direction without any gaps. Here, the substantially quadrangular pyramid shape is not only a perfect quadrangular pyramid shape, but also a shape in which the top of the quadrangular pyramid is chamfered to a curved surface or a plane, or a shape in which each triangular slope of the quadrangular pyramid is slightly curved. Etc. are also included.

Even in the form shown in FIG. 18, the optical sheet 20 is slightly diffused from the image light emitted from the image source 11, and the diffused image light causes the observer to see the non-image area F2 caused by the non-pixel area G2. It is possible to prevent it from being visually recognized. Further, the layer structure can be reduced as compared with the optical sheet 20 shown in FIG. 3 and the optical sheet 20 shown in FIG. 13, and the optical sheet 20 can be made thinner or lighter. Further, the optical sheet 20 can be manufactured more easily and inexpensively.
Further, by setting the orientation in which the optical sheet 20 is arranged so that the value of the angle θ described above is within an appropriate range, color bleeding can be prevented.

FIG. 19 is a diagram illustrating another form of the optical sheet 20. FIG. 19 is a view seen from the same direction as in FIG.
The optical sheet 20 does not need to be provided independently for each of the left and right eyes. For example, as shown in FIG. 19A, the optical sheet 20 may have an irregular shape connecting the left and right regions. Further, the optical sheet 20 may have a rectangular shape as shown in FIG. 19 (b). With such a shape, it becomes easy to arrange the optical sheet 20 at an angle θ with respect to the X direction and the Z direction in the SX direction and the SZ direction. Even in the form shown in FIG. 19, since the shape is symmetrical, an index indicating the direction of the optical sheet 20 may be provided or the shape may be asymmetric.

FIG. 20 is a diagram illustrating another embodiment of the head-mounted display device 1 of the present embodiment.
As shown in FIG. 20, the optical sheet 20 may be arranged on the observer side (−Y side) of the lens 12. Even if such an arrangement is adopted, the display device 1 displays a clear image with less blurring to the observer, and the non-image area caused by the non-pixel area G2 of the image source 11 due to the minute diffusion of the image light. It is possible to prevent F2 from being noticeably observed.
Further, by setting the orientation in which the optical sheet 20 is arranged so that the value of the angle θ described above is within an appropriate range, color bleeding can be prevented.

(Transformed form)
Various modifications and changes are possible without being limited to the embodiments described above, and these are also within the scope of the present invention.

(1) In the present embodiment, both the second direction in which the first unit shape 21a is arranged and the fourth direction in which the second unit shape 23a is arranged are set in the first proximity arrangement direction. And an example of arranging at an angle with respect to the second proximity arrangement direction and the like has been described. Not limited to this, for example, only the second direction is arranged at an angle with respect to the first proximity arrangement direction, the second proximity arrangement direction, and the like, and the fourth direction is the first proximity arrangement direction or the second proximity arrangement direction. It may be the same direction as the proximity arrangement direction. Even in such a case, it is possible to obtain the effect of preventing color bleeding.

(2) In the present embodiment or the like, an example in which the first direction in which the first unit shape 21a extends and the third direction in which the second unit shape 23a extends are orthogonal to each other is given. explained. Not limited to this, for example, a configuration in which the first direction in which the first unit shape 21a extends and the third direction in which the second unit shape 23a extends intersect at an angle other than 90 degrees. May be. Even in that case, the second direction in which the first unit shape 21a is arranged and the fourth direction in which the second unit shape 23a is arranged are defined as the first proximity arrangement direction and the second proximity arrangement direction. Color bleeding can be suppressed by arranging at an angle of 5 degrees or more with respect to the arrangement direction.
Further, the second direction and the fourth direction are arranged at an angle of 6 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction, and the second direction and the fourth direction are arranged at an angle of 6 degrees or more. If the arrangement is performed at an angle of 3 degrees or more with respect to the three proximity arrangement directions and the fourth proximity arrangement direction, the effect of suppressing color bleeding can be further enhanced.

(3) In the present embodiment and the like, an example having a positioning shape (20a, 321a) for defining the position of the optical sheet 20 in the rotation direction in the sheet surface with respect to the image source 11 has been described. Not limited to this, for example, a positioning index may be provided on the optical sheet and the holding portion.

(4) In the present embodiment, the optical sheet 20 has two types of unit optical shapes and has been described with an example of performing diffusion in two directions. Not limited to this, for example, it may be a form in which diffusion is performed in only one type, that is, in only one direction, or a form in which diffusion is performed in three or more types (three or more directions).

The embodiments and modifications can be used in combination as appropriate, but detailed description thereof will be omitted. Further, the present invention is not limited to the embodiments described above.

1 Display device 5 Display device (conventional)
11 Image source 11a Display surface 12 Lens 12A Lens 12B Lens 12a Reflection suppression layer 20 Optical sheet 20A Optical sheet 20B Optical sheet 20a Convex portion 21 First optical layer 21a First unit shape 21b Flat portion 22 Second optical layer 23 Third Optical layer 23a Second unit shape 23b Flat part 24 Reflection suppression layer 30 Housing 31 Holding part 32 Holding part 33 Holding part 51 Image source 52 Lens 311 Opening 321 Opening 321a Recessed 331 Opening

Claims (6)

An image source that emits image light and
A lens that magnifies the image light and emits it to the observer side.
Between the video source and the lens, or is placed on the viewer side of the lens, an optical sheet Ru to diffuse the image light,
With
The optical sheet has a unit shape formed in a convex or concave shape, and has a unit shape.
The unit shapes are arranged at least in a specific arrangement direction in the sheet plane orthogonal to the thickness direction of the optical sheet.
The image source is configured by arranging pixels of a plurality of colors side by side.
The direction in which the distance between pixels of the same color is closest is defined as the first proximity arrangement direction.
When a direction different from the first proximity arrangement direction and the direction in which the pixels of the same color are close to each other next to the first proximity arrangement direction is defined as the second proximity arrangement direction,
The specific arrangement direction is arranged at an angle of 5 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction, and is a display device worn on the observer's head. In the display device according to claim 1,
The direction different from the first proximity arrangement direction and the second proximity arrangement direction, and the direction in which the distance between pixels of the same color is closest to each other next to the second proximity arrangement direction is the third proximity arrangement direction. As defined as
The directions are different from the first proximity arrangement direction, the second proximity arrangement direction, and the third proximity arrangement direction, and the distance between the pixels of the same color next to the third proximity arrangement direction is the closest. When the direction is specified as the 4th proximity array direction,
The specific arrangement direction is arranged at an angle of 6 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction.
The specific arrangement direction is arranged at an angle of 3 degrees or more with respect to the third proximity arrangement direction and the fourth proximity arrangement direction.
A display device characterized by. In the display device according to claim 1 or 2.
The optical sheet is
The first unit shape formed in a convex or concave shape at the first interface, which is the interface between the two layers,
A second unit shape formed in a convex or concave shape at a second interface, which is an interface between two layers different from the first interface,
Have and
The first unit shape extends in the first direction in the sheet surface orthogonal to the thickness direction of the optical sheet, and is arranged in the second direction orthogonal to the first direction.
The second unit shape extends in a third direction within the sheet surface that is orthogonal to the thickness direction of the optical sheet and intersects the first direction, and is orthogonal to the third direction. Arranged in 4 directions,
The specific arrangement direction is the second direction and the fourth direction.
A display device characterized by. In the display device according to claim 3,
The first refractive index difference Δn1, which is the difference in the refractive indexes of adjacent layers at the first interface, satisfies 0.005 ≦ Δn1 ≦ 0.1.
The second refractive index difference Δn2, which is the difference in the refractive indexes of adjacent layers at the second interface, satisfies 0.005 ≦ Δn2 ≦ 0.1.
A display device characterized by. In the display device according to any one of claims 1 to 4.
It is provided with a holding portion for holding the optical sheet.
At least one of the optical sheet and the holding portion is provided with a positioning shape or a positioning index for defining the position of the optical sheet in the sheet surface in the rotational direction with respect to the image source.
A display device characterized by. In the display device according to any one of claims 1 to 5.
The distance between the optical sheet and the image source shall be 100 times or more the array pitch of the pixels.
A display device characterized by.

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