JP2022070877A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device with which it is possible to suppress a non-video region from being visually recognized due to a non-pixel region existing between the pixels of a vide source.

SOLUTION: A display device 1 is a head-mount type display device mounted to the head of an observer for displaying a video in front of the eyes of the observer, the display device 1 comprising: a vide source 11 for emitting video light; two convex lenses 12A, 12B corresponding to the left and right eyes of the observer, respectively, for emitting video light to the observer side; and an optical sheet 20 arranged between the video source 11 and the lenses 12A, 12B, for diffusing the video light. The optical sheet 20 has directivity with respect to the diffusion of light, and has a direction in which the diffusion of the video light is largest in a direction in plane of the sheet. The video source 11 has two regions for displaying videos corresponding to the left and right eyes of the observer, and the lenses 12A, 12B are arranged so as to correspond to the two regions, respectively, thereby independently displaying videos corresponding to the left and right eyes of the observer, respectively.

SELECTED DRAWING: Figure 1

COPYRIGHT: (C)2022,JPO&INPIT

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, which allows an observer to observe 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, and only the image is used. 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-mentioned problems by the following solution means. 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 a head-mounted display device that is mounted on the observer's head and displays an image in front of the observer's eyes, and comprises an image source (11) that emits image light. Two convex lenses (12A, 12B) corresponding to each of the left and right eyes of the observer and emitting the image light to the observer side, and the image light arranged between the image source and the convex lens. The optical sheet (20) is provided with an optical sheet (20) for diffusing the light, and the optical sheet has directionality with respect to the diffusion of light. The image source has two regions for displaying images corresponding to the left and right eyes of the observer, and the convex lens is arranged so as to correspond to the two regions. The display device is a display device (1) characterized in that images corresponding to the left and right eyes of the observer are independently displayed.

According to the second invention, in the display device of the first invention, the image source (11) is configured by arranging a plurality of pixels side by side, and the direction in which the center distance between the pixels is closest to each other. Is defined as the first proximity arrangement direction, and the direction different from the first proximity arrangement direction and the center distance between the pixels is close to the pixel after the first proximity arrangement direction is the second proximity. It is defined as an arrangement direction, and the direction in which the diffusion of the image light is the largest is characterized in that it is arranged at an angle of 5 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction. Display device (1).

According to the third aspect of the present invention, in the display device of the second invention, either the first proximity arrangement direction or the second proximity arrangement direction is 45 degrees with respect to the vertical direction or the horizontal direction of the screen of the image source. It is a display device (1) characterized by the direction of forming.

The fourth invention is different from the first proximity arrangement direction and the second proximity arrangement direction for the pixels arranged in the image source (11) in the display device of the second invention or the third invention. The direction in which the center distance between the pixels is close to each other next to the second proximity arrangement direction is defined as the third proximity arrangement direction, and an integer of 3 or more is defined as N, and hereinafter, the first The direction different from the Nth proximity arrangement direction from the proximity arrangement direction and the direction in which the center distance between the pixels is close to the Nth proximity arrangement direction is defined as the (N + 1) proximity arrangement direction. The direction in which the diffusion of the video light is maximum is arranged at an angle of 2 degrees or less with respect to the Nth proximity arrangement direction, and is out of the center distance between the pixels in the Nth proximity arrangement direction. The display device (1), characterized in that the center distance in the direction corresponding to the direction in which the diffusion of the image light is maximum is within 7 times the center distance between the pixels in the first proximity arrangement direction. Is.

A fifth aspect of the present invention is the display device (1) of the fourth aspect of the present invention, wherein the direction in which the diffusion of the image light is maximum is the same as the direction in which the Nth proximity arrangement is performed. ..

According to the sixth aspect of the present invention, in any of the display devices from the second invention to the fifth invention, the direction in which the diffusion of the image light is the largest is an angle of 10 degrees or more with respect to the first proximity arrangement direction. The display device (1) is characterized in that it is arranged by holding it and is arranged at an angle of 5 degrees or more with respect to the second proximity arrangement direction.

The seventh invention is a straight line drawn in a direction along the direction in which the diffusion of the image light is maximum in any of the display devices from the second invention to the sixth invention, and is the most of the pixels. When the image source (11) is virtually divided into a region including the pixels and a region not including the pixels by drawing a straight line passing through the outer diameter portion, the area ratio of the region including the pixels is 80. % Or more, the display device (1) is characterized in that the direction in which the diffusion of the image light is the largest is provided.

The eighth aspect of the invention is characterized in that, in the display device of the seventh invention, the direction in which the diffusion of the image light is the largest is provided so that the area ratio of the region including the pixels is 100%. It is a display device (1).

According to a ninth aspect of the present invention, in any of the display devices from the second invention to the eighth invention, the image source (11) is configured by arranging the pixels of a plurality of colors side by side, and the image light. The display device (1) is characterized in that pixels of different colors are included and arranged in the direction along the direction in which the diffusion of light is maximum.

According to a tenth aspect of the present invention, in any of the display devices from the first invention to the ninth invention, the optical sheet (20) has a unit shape (21a) formed in a convex or concave shape. The unit shape is arranged at least in a specific arrangement direction in the sheet plane orthogonal to the thickness direction of the optical sheet, and the optical sheet diffuses light in the arrangement direction of the unit shape, and the unit shape is , The second direction extending in the first direction in the sheet surface orthogonal to the thickness direction of the optical sheet and orthogonal to the first direction in the sheet surface is arranged as the specific arrangement direction. The display device (1) is characterized in that the direction in which the diffusion of the image light is the largest is the specific arrangement direction.

The eleventh invention is characterized in that, in the display device of the tenth invention, the angle δ formed by the specific arrangement direction with respect to the vertical direction of the screen of the image source is 8 ° or more and 25 ° or less. Display device (1).

According to the twelfth invention, in the display device of the tenth invention or the eleventh invention, the optical sheet (20) is composed of two or more different layers, and the unit shape (21a) is different. It is a display device (1) characterized by being configured at the interface of layers.

According to the thirteenth invention, in any of the display devices from the first invention to the twelfth invention, the optical sheets (20) are arranged in two sheets (20A, 20B) so as to correspond to the two regions, respectively. It is a display device (1) characterized by the fact that it is done.

According to the fourteenth invention, in any of the display devices from the first invention to the thirteenth invention, the optical sheet (20) has a diffusion angle in the direction in which the diffusion of the image light is the largest. The display device (1) is characterized in that the diffusion is 10 times or more the diffusion angle in the direction of the smallest diffusion.

A fifteenth invention is a filler that reduces a difference in refractive index between the optical sheet (20) and the image source (11) in any of the display devices from the first invention to the fourteenth invention. The display device (1) is characterized in that the gap is filled with.

A sixteenth aspect of the present invention is the display device according to any one of the first to fifteenth inventions, wherein the optical sheet (20) has a reflection suppression layer, a hard coat layer, an antistatic layer, and an antifouling layer. The display device (1) is characterized by having at least one layer of the above.

According to the seventeenth invention, in any of the display devices from the first invention to the sixteenth invention, the video source (11) occupies 50% or less of the light emitting region in the video display region. This is a characteristic display device (1).

The eighteenth invention is a display device according to any one of the first to seventeenth inventions, wherein the pixel arrangement of the image source (11) is a diamond pen tile arrangement (the display device). 1).

INDUSTRIAL APPLICABILITY 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 luminance 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 a figure which shows the distance K1, the distance L1, and the effective radius R3 of a lens 12. It is a figure explaining the specific arrangement direction of an optical sheet 20 together with an example of the pixel arrangement of the image source 11. It is a figure schematically showing how the optical sheet 20 diffuses the image light L when the optical sheet 20 is arranged by aligning the specific arrangement direction (SZ direction) of the optical sheet 20 with the third proximity arrangement direction DL3. be. It is a figure schematically showing how the optical sheet 20 diffuses the image light L when the optical sheet 20 is arranged by aligning the specific arrangement direction (SZ direction) of the optical sheet 20 with the first proximity arrangement direction DL1. be. It is a figure which shows the result of having visually evaluated the appearance of the observed image by gradually changing and arranging the angle δ which shows the specific arrangement direction (SZ direction) of an optical sheet 20. It is a figure explaining another fixed form of an optical sheet 20. It is a figure explaining the light emitting area of one pixel. It is a figure explaining the spread width W of a light emitting area EA.

Hereinafter, embodiments of the present invention will be described with reference to the drawings and the like. In addition, each figure 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-shaped 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 with the display device 1 attached to the head of the observer. 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 δ (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 (tilt) 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. 1. 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 the 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 a video 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 of displaying an image on 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 is used. It may be arranged with respect to the eye E1 and display an image 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 the 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 it is used. 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 the positions corresponding to the openings 311 (311A, 311B).

The optical sheet 20 has a unit shape as described later. Then, in the optical sheet 20, the arrangement direction of the unit shape (direction orthogonal to the extending direction in the sheet surface) is a specific pixel direction (first proximity arrangement direction, second proximity arrangement direction) of the pixel arrangement in the image source 11. , 3rd proximity arrangement direction, 4th proximity arrangement direction, 5th proximity arrangement direction, 6th proximity arrangement direction, 7th proximity arrangement direction). Although the specific pixel direction will be described later, the optical sheet 20 can be arranged so as to face the holding portion 32 in a specific arrangement direction (direction having a specific angle with respect to the above-mentioned specific pixel direction). As described above, 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 extending direction and the arrangement 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 δ.
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 XZ 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 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 the lens 12 (12A, 12B) is placed in the opening 331 (331A, 331B). It is fitted and held.

The image source 11 is a display element 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. 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 portion 31 so that the display surface 11a is on the observer side (−Y side).
In the present embodiment, the display device 1 is provided with 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 this 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 an antireflection 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 diffusing function of slightly diffusing 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 (back 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) 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 forming an image arranged in the display unit 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 interfere with 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.
Note that FIGS. 5 and 6 show a form in which rectangular pixel regions G1 are arranged side by side in the X direction and the Z direction for ease of understanding.

In the optical sheet 20 of the present embodiment, as shown in FIG. 3, the reflection suppression layer 24, the first optical layer 21, and the second optical layer 22 are laminated in this order from the image source side (back surface side, + Y (SY) side). Has been done. The optical sheet 20 has a plurality of unit shapes 21a formed at the interface between the first optical layer 21 and the second optical layer 22.
The first optical layer 21 is a layer having light transmittance and is located on the image source side (+ Y (SY) side) of the second optical layer 22 in the thickness direction (Y (SY) direction) of the optical sheet 20. be. The surface of the first optical layer 21 on the image source side is formed substantially flat. As shown in FIG. 3B, a plurality of convex unit shapes 21a are formed on the surface of the first optical layer 21 on the observer side (−Y (SY) side). The unit shape 21a is convex toward the observer side (−Y (SY) side).

The unit shape 21a extends in the SX direction along the surface of the first optical layer 21 on the image source side, and has an SZ direction orthogonal to the extending direction (SX direction) (hereinafter, a specific arrangement as appropriate). It is a lenticular lens shape that is arranged in a plurality of directions (referred to as directions) and has a substantially arcuate cross-sectional shape on a plane (SY-SZ plane) parallel to the SZ direction and the thickness direction. Here, the substantially arc shape means not only a perfect circular arc but also a curved shape including a part such as an ellipse or an ellipse.

The second optical layer 22 is a layer having light transmittance located on the most observer side (—Y (SY) side) of the optical sheet 20. The surface 22a on the observer side of the second optical layer 22 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, the surface of the second optical layer 22 on the image source side (+ Y (SY) side) has a shape that follows the unit shape 21a.

When viewed from the thickness direction of the optical sheet 20 (normal direction of the sheet surface, Y (SY) direction), the SZ direction (specific arrangement direction) is arranged so as to form a specific angle with respect to the Z direction. There is. The optical sheet 20 has a light diffusing effect in the SZ direction (specific arrangement direction), but has almost no light diffusing effect in the SX direction orthogonal to the SZ direction. Therefore, the SZ direction (specific arrangement direction) is the direction in which the diffusion is the largest. In the application of the present embodiment, the diffusion of the light diffused by the optical sheet 20 is such that the diffusion angle in the direction with the largest diffusion (SZ direction) is 10 times or more the diffusion angle in the direction with the smallest diffusion (SX direction). Is desirable. As a result, directivity is generated in the diffused light, and by appropriately arranging the relationship between the pixel arrangement and the specific arrangement direction of the optical sheet 20, it is possible to obtain the effect peculiar to the present application. The details regarding the specific arrangement direction (SZ direction) of the optical sheet 20 will be described later.

Assuming that the relationship between the brightness of light passing through an interface in which a plurality of unit shapes of the optical sheet 20 are arranged and the diffusion angle is as shown in FIG. 4, for example, the component that reaches the observer through the lens 12 is It is assumed that the diffusion angle θ is a component in the range of −φ to +φ. If the component of light diffused in this range is used as an index of the degree of diffusion of the interface, an appropriate diffusion action can be evaluated as an interface in which a plurality of unit shapes are arranged.
Further, when the pixel arrangement pitch PP in which the pixel region G1 of the image source 11 is arranged changes, the degree of the required diffusion action also changes, so this pixel arrangement pitch PP is also an important parameter.
Further, if the distance between the lens 12 and the interface on which the plurality of unit shapes of the optical sheet 20 are formed changes, the effect of the interface on which the plurality of unit shapes are formed diffuses the image light L also changes.

Therefore, the brightness at the diffusion angle θ due to the interface on which the unit shape 21a is formed is set to I ₁ (θ), and the distance between the lens 12 and the interface on which the unit shape 21a is formed is set to K1. When the radius is R3, the average diffusion angle θave1 of the interface on which the unit shape 21a is formed with respect to the components in the range of −φ to +φ is defined by the following equation.

The distance between the interface on which the unit shape 21a is formed and the display layer 11e of the image source 11 is L1, the pixel arrangement pitch in which the pixel regions G1 are arranged is PP, and θave1 × L1 / PP is the unit shape 21a. It is set as an index indicating the degree to which the non-image region F2, which is the cause of the non-pixel region G2, is suppressed from being visually recognized by the observer due to the action of diffusing the image light L, that is, an index of the degree of blurring.
The pixel arrangement pitch PP of the pixel region G1 of the image source 11 used in the display device 1 is 400 to 500 ppi (pixel per inch), and in this embodiment, PP = 0.0508 mm (500 ppi).

FIG. 7 is a diagram showing a distance K1, a distance L1, and an effective radius R3 of the lens 12.
The unit shape 21a is a shape that is convex in the thickness direction (Y direction, SY direction) of the optical sheet 20. Further, as for the lens 12, it is possible to use a plurality of lenses. Therefore, the distance K1 between the lens 12 and the interface on which a plurality of unit shapes 21a are formed is from the position of the average height of the unit shape 21a to the center of the lens 12 (the principal point in the case of a single lens). The distance is.

Further, when the image source 11 is, for example, an organic EL display, as illustrated in FIG. 7, the transparent substrate 11b, the transparent electrode 11c, the organic hole transport layer 11d, and the organic light emitting layer (from the observer side). A plurality of layers are laminated, such as the display layer) 11e, the organic electron transport layer 11f, and the metal electrode 11g. The non-pixel region G2 is formed on the display layer 11e.
Therefore, the above-mentioned distance L1 may be set from the display layer 11e to a position where the average height of the unit shape 21a is reached.

When a plurality of types of optical sheets 20 were created by changing various parameters and the actual appearance was evaluated, the degree of suppressing the non-image area F2 from being visually recognized by the observer and θave1 × L1 / PP. There is a good correlation between them.
5 ≦ θave1 × L1 / PP ≦ 60 ・ ・ ・ (Equation 1)
When the above formula is satisfied, it is possible to observe a good image in which the non-image area F2 is difficult to be visually recognized by the observer, the pixel area G1 (pixels) cannot be seen independently, and the image is not too blurred. rice field.
In addition, it was possible to observe the optimum image when the following stricter conditions were satisfied.
23 ≦ θave1 × L1 / PP ≦ 35 ・ ・ ・ (Equation 2)

When θave1 × L1 / PP is less than 5, the pixel region G1 (pixel) is seen independently by the observer, and the non-video region F2 is conspicuously visible. When θave1 × L1 / PP is 5 or more, the pixel region G1 cannot be seen independently due to the diffusion action, and the non-video region F2 is difficult to see. When θave1 × L1 / PP is 23 or more, the pixel region G1 (pixel) is optimally blurred, and the observer can hardly confirm the non-video region F2.
Further, when θave1 × L1 / PP exceeds 35, the pixel region G1 cannot be seen independently, but the sharpness of the image is slightly lowered as compared with the case where 23 or more and 35 or less are satisfied. When θave1 × L1 / PP is larger than 60, the pixel region G1 is not conspicuously visible to the observer, but the resolution of the image is lowered, the sharpness is significantly impaired, and the details cannot be confirmed. Become.
Therefore, it is preferable to satisfy the above (Equation 1), and it is more preferable to satisfy (Equation 2).

Further, by considering the relative positional relationship between the optical sheet 20, the image source 11, and the lens 12, the non-image area F2 caused by the non-pixel area G2 due to the action of diffusing the image light L by the optical sheet 20. It is possible to set an index indicating the degree to which the observer is prevented from being visually recognized by the observer.

Here, the refractive index of the region adjacent to each other via the interface on which the unit shape 21a is formed (the first optical layer 21 (unit shape 21a) and the second optical layer 22), whichever has the higher refractive index, is selected. Let it be na, and let nb be the refractive index whose refractive index is lower than na. At this time, the degree of diffusion D1 as an index indicating the degree to which the image light L is diffused by the unit shape 21a is set.
D1 = (P1 / R1) x (1- (nb / na)) x L1
Can be defined as.

The degree of diffusion D1 represents the degree to which light is diffused at the interface where the unit shape 21a is formed. If the ratio of the pixel array pitch PP in which the pixel region G1 is arranged and the diffusion degree D1, that is, D1 / PP is obtained, the interface on which the unit shape 21a is formed is caused by the non-pixel region G2 and is a non-video region. It can be used as an index showing the degree of suppressing F2 from being visually recognized by the observer.

Next, when a plurality of types of optical sheets 20 were created by changing various parameters and the actual appearance was evaluated, the degree of suppressing the non-image region F2 from being visually recognized by the observer and D1 / PP. There is a good correlation between them, and when the following equation is satisfied, the non-image area F2 is difficult for the observer to see, the pixel area G1 (pixels) cannot be seen independently, and the image is not too blurred. No, it turned out that a good image can be observed.
1.0 ≤ D1 / PP ≤ 3.0 ... (Equation 3)
If D1 / PP is less than 1.0, the pixel region G1 (pixel) is seen independently by the observer, and the non-video region F2 is also visually recognized by the observer. Further, when D1 / PP is larger than 3.0, the image is blurred and visually recognized by the observer. Therefore, it is preferable to satisfy the above (Equation 3).

Further, if the stricter conditions, that is, the following equations are satisfied, the non-video region F2 is hardly visible, the pixel region G1 (pixels) cannot be seen independently, and the video is not too blurred, which is an optimum image. Was able to be observed.
1.2 ≤ D1 / PP ≤ 2.0 ... (Equation 4)

As described above, by defining the range of the value of D1 / PP at the interface with respect to the optical sheet 20, the display device 1 of the present embodiment uses the image light L emitted from the image source 11 in the arrangement direction of the unit shape 21a. It can be slightly diffused in the (SZ direction). As a result, the display device 1 can display a clear image to the observer and prevent the non-image area F2 of the image source 11 from being visually recognized due to the slight diffusion of the image light L.

If the cross-sectional shape of the unit shape 21a is an elliptical shape or a partial oval shape and is not a perfect arc, approximate the shape with an arc and calculate the radius of the arc shape as R1. Just do it.

Next, at the interface where the unit shape 21a is formed, the relationship between the arrangement pitch P1 of the unit shape and the distance L1 between the interface and the display layer 11e will be described.
The optical sheet 20 has a different preferred array pitch P1 of the unit shape 21a depending on the distance L1 from the display layer 11e of the image source 11. This is because when the optical sheet 20 is close to the display layer 11e, moire is likely to occur between the pixel (pixel region G1) and the unit shape, and when the optical sheet 20 is far from the display layer 11e, diffraction is likely to occur. be.
It is preferable that the arrangement pitch P1 and the distance L1 of the unit shape 21a satisfy the following equations.
0.005 ≤ P1 / L1 ≤ 0.05 ... (Equation 5)
Further, it is more preferable to satisfy the following formula.
0.01 ≤ P1 / L1 ≤ 0.03 ... (Equation 6)
In the present embodiment, P1 / L1 = 0.02, which satisfies the above-mentioned preferable range and more preferable range.

When P1 / L1 is smaller than 0.005, the distance between the unit shape 21a and the pixel (display layer 11e) is too large, and the parallelism of the light entering the optical sheet 20 becomes high, or the pitch of the unit shape 21a. May become too small, and the influence of diffraction becomes large in the unit shape 21a, so that the required characteristics may not be obtained.
Further, when P1 / L1 is larger than 0.05, the distance between the unit shape 21a and the pixel (display layer 11e) is too close, and moire is likely to occur between the pixel and the unit shape 21a.
Therefore, it is preferable that P1 / L1 satisfy the above range.

Further, in the optical sheet 20 of the present embodiment, the half-value angle 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 is set to α in a specific arrangement direction, and the luminance of the transmitted light is set to α. When the diffusion angle at which is 1/20 of the maximum brightness is β, it is preferably formed so as to satisfy β ≦ 5 × α.
Here, the half-value angle α of the optical sheet 20 means that the brightness of the light is the maximum value in the arrangement direction and the extending direction of the unit shape from the observation position of the sheet surface of the optical sheet 20 where the brightness of the light is the maximum value. The angle with the largest absolute value among the observation angles that are half the value. Further, the diffusion angle β is set to a value of 1/20 of the maximum value of the light brightness in the arrangement direction and the extending direction of the unit shape from the observation position of the sheet surface of the optical sheet 20 where the light brightness is the maximum value. The angle with the largest absolute value among the observation angles.

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, from the viewpoint of more effectively exerting the effect of making the non-video region F2 caused by the non-pixel region G2 inconspicuous, the diffusion angle β is more likely to be substantially equal to or close to the half-value angle α. desirable.

Further, in the optical sheet 20 of the present embodiment, the refractive index difference between the optical layers adjacent to each other, that is, the first refractive index difference Δn1, which is the refractive index difference between the first optical layer 21 and the second optical layer 22, is 0. It is formed so as to satisfy .005 ≦ Δn1 ≦ 0.2.

If the first refractive index difference Δn1 is 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, so that a sufficient diffusion effect is exhibited. It is not desirable because it disappears. Further, when the first refractive index difference Δn1 is larger than 0.2, the refraction of light between the optical layers becomes too large, and the image light transmitted through the optical sheet becomes unclear, which is not desirable.

In this way, the range of the values of the half-value angle α and the diffusion angle β of the optical sheet 20 and the range of the first refractive index difference Δn1 of the layers adjacent to each other with the surface on which the unit shape 21a is formed as an interface are defined. Thereby, the display device 1 of the present embodiment can slightly diffuse the image light L emitted from the image source 11 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 region F2 caused by the non-pixel region G2 of the image source 11 from becoming conspicuous due to the minute diffusion of the image light L. can do.

The first optical layer 21 is made of a highly light-transmitting PC (polycarbonate) resin, MS (methylmethacrylate / styrene) resin, acrylic resin, or the like.
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, and in the present embodiment, it is higher than the refractive index of the first optical layer 21. It is formed with a low refractive index.

When the cross-sectional shape of the unit shape 21a in the SY-SZ cross section is formed in an arc shape, the arrangement pitch of the unit shape 21a in the SZ direction is set to P1 as shown in FIG. 3D, and the unit shape 21a has an arrangement pitch of P1. When the radius of curvature of the arcuate cross-sectional shape in the SY-SZ cross section is R1, the unit shape 21a is preferably formed in the range of 0.05 ≦ P1 / R1 ≦ 1.9.

By forming the array pitch P1 and the radius of curvature R1 of the unit shape 21a in the above range in this way, the display device 1 efficiently and evenly diffuses the image light emitted from the image source 11 slightly in the SZ direction. be able to.

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.
The antireflection layer 24 is, like the reflection suppression layer 12a provided on the image source side of the lens 12, 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 having a reflection suppressing 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 side. 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 side, so that 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 is possible to suppress the reflection at the interface between the optical sheet 20 and the air and cause stray light in the optical sheet 20. The contrast of the image can be improved.
Further, a layer having a hard coat function, an antistatic 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 obstruction of visual recognition of the image.

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 suppressing layer having a moth-eye structure has a high reflection suppressing 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 passes through the first optical layer 21 and is slightly diffused by the unit shape 21a of the interface between the first optical layer 21 and the second optical layer 22. It transmits through the second optical layer 22.
The image light L transmitted through the second optical layer 22 is emitted 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 lens 12 (12A, 12B). Then, the image light L is enlarged by the lens 12 and emitted to the observer side (−Y (SY) side).

Next, the point that the specific arrangement direction (SZ direction) of the optical sheet 20 is inclined with respect to the image source 11 by the angle δ will be described.
FIG. 8 is a diagram illustrating a specific arrangement direction of the optical sheet 20 together with an example of the pixel arrangement of the image source 11.
As described above, the main purpose of providing the optical sheet 20 is to prevent the non-pixel region G2 (see FIG. 6) between pixels from being conspicuously visible due to the magnified observation of the image source 11. That is. This phenomenon tends to appear particularly prominently in organic EL displays. This is because in the organic EL display, the ratio of the light emitting region (pixel region) to the video display region tends to be low. In particular, when the ratio of the light emitting region (pixel region) in the video display region of the video source 11 is 50% or less, particularly 30% or less, the effect of the optical sheet 20 is more exhibited. In the case of the present embodiment shown in FIG. 8, the ratio of the light emitting region (pixel region) in the video display region of the video source 11 is about 20%.

As the pixel arrangement in the organic EL display, the diamond pen tile arrangement shown in FIG. 8 is known. In this diamond pen tile arrangement, the pixels are arranged in a square grid in a direction inclined by 45 degrees with respect to the vertical and horizontal directions of the rectangular display area. Further, in the diamond pen tile arrangement, the number of greens (G) is twice the number of reds (R) and blues (B). In FIG. 8, the pixels of each color of red (R), green (G), and blue (B) are shown by imitating the shape and size of the actual shape and size, and some of the pixels are included. , The letters R, G, and B indicating the color are added. Pixels having the same shape and size indicate pixels of the same color. That is, the smaller of the square pixels is the red (R) pixel, the larger of the square pixels is the blue (B) pixel, and the round one is the green (G) pixel. be.
In the present specification, a diamond pen tile array configured in a square array (same vertical and horizontal spacing) in the 45-degree direction will be described as an example, but for example, a pixel array having slightly different vertical and horizontal spacing will be described. The present invention can be similarly used for the element of. Therefore, the claims and the inventions disclosed in the present specification are not limited to those applicable to the square diamond pen tile arrangement.

In such a pixel arrangement, attention is paid to the distance between the center positions of each pixel regardless of the difference in emission color (R, G, B). In the diamond pen tile arrangement, each pixel is arranged at equal intervals as long as the difference in color is excluded, so any pixel may be used as a reference. In the example of FIG. 8, the red (R) pixel at the lower part in the figure is used as a reference. Then, the following nine directions are defined by the distance between the center of the pixel (center distance) (hereinafter, the distance between the pixels is referred to as the distance between the centers).

(1st proximity arrangement direction DL1)
The direction in which the distance between the pixel centers is closest to the reference pixel selected as appropriate is defined as the first proximity arrangement direction DL1. The angle formed by the first proximity arrangement direction DL1 with the Z direction is 45 degrees.
It should be noted that the reference pixel is set in the explanation for facilitating understanding, and it is not necessary to determine one pixel as a reference.

(Second proximity array direction DL2)
The direction different from the first proximity arrangement direction and the direction in which the center distance between the pixels is close to each other next to the first proximity arrangement direction is defined as the second proximity arrangement direction. The angle formed by the second proximity arrangement direction DL2 with respect to the Z direction is 0 degrees.

(3rd proximity arrangement direction DL3)
The direction different from the first proximity arrangement direction and the second proximity arrangement direction, and the direction in which the center distance between the pixels is close to each other next to the second proximity arrangement direction is defined as the third proximity arrangement direction. The angle formed by the third proximity arrangement direction DL3 with respect to the Z direction is 18.4 degrees.

(4th proximity arrangement direction DL4)
The direction different from the first proximity arrangement direction to the third proximity arrangement direction, and the direction in which the center distance between the pixels is close to each other next to the third proximity arrangement direction is defined as the fourth proximity arrangement direction. The angle formed by the fourth proximity arrangement direction DL4 with the Z direction is 26.6 degrees.

(Fifth proximity arrangement direction DL5)
The direction different from the first proximity arrangement direction to the fourth proximity arrangement direction, and the direction in which the center distance between the pixels is close to each other next to the fourth proximity arrangement direction is defined as the fifth proximity arrangement direction. The angle formed by the fifth proximity arrangement direction DL5 with the Z direction is 11.3 degrees.

(6th proximity arrangement direction DL6)
The direction different from the first proximity arrangement direction to the fifth proximity arrangement direction and the direction in which the center distance between the pixels is close to each other next to the fifth proximity arrangement direction is defined as the sixth proximity arrangement direction. The angle formed by the sixth proximity arrangement direction DL6 with the Z direction is 31.0 degrees.

(7th proximity arrangement direction DL7)
The direction different from the 6th proximity arrangement direction from the 1st proximity arrangement direction and the direction in which the center distance between the pixels is close to the 6th proximity arrangement direction is defined as the 7th proximity arrangement direction. The angle formed by the 7th proximity arrangement direction DL7 with the Z direction is 8.1 degrees.

(8th proximity arrangement direction DL8)
The direction different from the 7th proximity arrangement direction from the 1st proximity arrangement direction and the direction in which the center distance between the pixels is close to the 7th proximity arrangement direction is defined as the 8th proximity arrangement direction. The angle formed by the 7th proximity arrangement direction DL7 with the Z direction is 33.7 degrees.

(9th proximity arrangement direction DL9)
The direction different from the 8th proximity arrangement direction from the 1st proximity arrangement direction and the direction in which the center distance between the pixels is close to the 8th proximity arrangement direction is defined as the 9th proximity arrangement direction. The angle formed by the eighth proximity arrangement direction DL8 with respect to the Z direction is 23.2 degrees.

(Nth proximity array direction)
In FIG. 8, only the 9th proximity array direction DL9 is illustrated, but the direction is different from the 1st proximity array direction to the Nth proximity array direction, where N is an integer of 3 or more, and is the Nth proximity array direction. Next, the direction in which the center distances between the pixels are close to each other can be generalized and defined as the (N + 1) proximity arrangement direction. And even in this Nth proximity arrangement direction, if the condition is satisfied, it can be effectively used in relation to a specific arrangement direction. However, in the following description, in order to facilitate understanding, the description will be made using the first proximity arrangement direction DL1 to the ninth proximity arrangement direction DL9 shown in FIG.

Here, in order to facilitate understanding, the nine directions from the first proximity arrangement direction to the ninth proximity arrangement direction will be described from the Z direction to the counterclockwise direction as shown in FIG. However, these directions also exist in a direction that is line-symmetrical with the straight line in the Z direction as the axis of symmetry and a direction that is line-symmetrical with the straight line in the X direction as the axis of symmetry. Therefore, the nine directions from the first proximity arrangement direction to the ninth proximity arrangement direction can be set in four directions for each. The same applies to the Nth proximity arrangement direction.

By arranging the specific arrangement direction (SZ direction) of the optical sheet 20 in an appropriate angular relationship with respect to the nine directions from the first proximity arrangement direction to the ninth proximity arrangement direction, a clear image can be seen by the observer. It was found that the non-image region F2 of the image source 11 can be suppressed from being visually recognized by the slight diffusion of the image light L.

FIG. 9 schematically shows how the optical sheet 20 diffuses the image light L when the optical sheet 20 is arranged so that the specific arrangement direction (SZ direction) of the optical sheet 20 coincides with the third proximity arrangement direction DL3. It is a figure shown.
As described above, the optical sheet 20 diffuses the image light L in the arrangement direction (SZ direction) of the unit shape 21a, but has almost no diffusion action in the direction orthogonal to the arrangement direction (SX direction). .. Therefore, the diffusion of light diffused by the optical sheet 20 as in the diffusion ranges DR, DG, and DB shown in FIG. 9 has directivity with respect to the direction in the sheet surface of the optical sheet 20. If the direction of this directivity, that is, the arrangement direction (SZ direction) of the unit shape 21a is an appropriate direction as in the example of FIG. 9, as shown in FIG. 9, in the non-image region F2 of the image source 11. It is possible to prevent the non-video region F2 of the video source 11 from being visually recognized due to the spread of the video light diffused in the corresponding region.

FIG. 10 schematically shows how the optical sheet 20 diffuses the image light L when the optical sheet 20 is arranged so that the specific arrangement direction (SZ direction) of the optical sheet 20 coincides with the first proximity arrangement direction DL1. It is a figure shown.
Compared with the case of FIG. 9, in the case of FIG. 10, since the range in which the video light L is diffused is not properly arranged, the non-video region F2 of the video source 11 is visually recognized. It is large, and the beneficial effect of providing the optical sheet 20 has not been sufficiently obtained.

As described above, it is very important what kind of orientation the optical sheet 20 is oriented in a specific arrangement direction (SZ direction). Therefore, the appearance of the observed image was visually evaluated by arranging the optical sheet 20 by gradually changing the angle δ indicating a specific arrangement direction (SZ direction). The evaluation criteria for this visual evaluation are whether or not the non-image region F2 of the image source 11 can be suppressed from being visually recognized, and whether or not the image can be clearly observed.

FIG. 11 is a diagram showing the results of visually evaluating the appearance of the observed image by arranging the optical sheets 20 by gradually changing the angle δ indicating a specific arrangement direction (SZ direction). The circles in FIG. 11 indicate that the non-image region F2 of the image source 11 could be suppressed from being visually recognized, and that a clear image could be observed. The △ mark indicates that it can be used, although it is inferior to the ○ mark. The x mark indicates that the non-image area F2 of the image source 11 cannot be suppressed from being visually recognized, or the image is unclear.
From FIG. 11, it can be said that the optical sheet 20 is preferably arranged in the range of the angle δ from 8 degrees to 25 degrees, and more preferably arranged in the range of the angle δ in the range of 8 degrees to 18 degrees. However, this numerical range is premised on using the image source 11 of the diamond pen tile arrangement. From the viewpoint of suppressing the non-visual area F2 from being visually recognized, it is desirable to define a specific arrangement direction (SZ direction) of the optical sheet 20 from the arrangement of pixels.

That is, the orientation of the optical sheet 20 determines whether or not the effectiveness of the optical sheet 20 is exhibited in relation to the arrangement of pixels. Therefore, based on the results of FIG. 11, how the specific arrangement direction (SZ direction) of the optical sheet 20 is set with respect to the above-mentioned seven directions from the first proximity arrangement direction to the seventh proximity arrangement direction. It is specified as follows specifically whether it should be arranged.

The optical sheet 20 has a specific arrangement direction of the third proximity arrangement direction DL3, the fourth proximity arrangement direction DL4, the fifth proximity arrangement direction DL5, or the sixth proximity arrangement direction DL6, or the seventh. It is desirable that the DL7 is arranged at an angle of 2 degrees or less with respect to the DL7 in the proximity arrangement direction, the DL8 in the eighth proximity arrangement direction, and the DL9 in the ninth proximity arrangement direction.
By arranging the optical sheet 20 in this way, a clear image can be displayed to the observer, and the non-image area F2 of the image source 11 is suppressed from being visually recognized by the minute diffusion of the image light L. be able to.

Further, it is desirable that the optical sheet 20 is arranged so that its specific arrangement direction is at an angle of 5 degrees or more with respect to the first proximity arrangement direction DL1 and the second proximity arrangement direction DL2.
More preferably, the optical sheet 20 is arranged with its specific arrangement direction at an angle of 10 degrees or more with respect to the first proximity arrangement direction DL1 and 5 with respect to the second proximity arrangement direction DL2. It is preferable that they are arranged at an angle of degrees or more.
By arranging the optical sheet 20 in this way, it is possible to avoid an improper arrangement as shown in FIG. 10, a clear image can be displayed to the observer, and the image light L can be displayed. It is possible to prevent the non-image region F2 of the image source 11 from being visually recognized due to the slight diffusion.

Further, the optical sheet 20 has a specific arrangement direction of the third proximity arrangement direction DL3, the fourth proximity arrangement direction DL4, the fifth proximity arrangement direction DL5, the sixth proximity arrangement direction DL6, and the seventh proximity arrangement. It is desirable that it is in the same direction as any of the directions DL7.
By arranging the optical sheet 20 in this way, a clear image can be displayed to the observer, and the non-image area F2 of the image source 11 is suppressed from being visually recognized by the minute diffusion of the image light L. be able to.

The optical sheet 20 is a straight line drawn in a direction along the specific arrangement direction, and a straight line passing through the outermost diameter portion of the pixel is drawn to virtualize a region containing pixels and a region not containing pixels. When the image source 11 is divided, it is desirable that a specific arrangement direction is provided so that the area ratio of the region including the pixels is 80% or more, more preferably 100%. The area ratio of the region including the pixels will be described with reference to FIG. 10 shown above. FIG. 10 shows a case where the optical sheet 20 is arranged so that the specific arrangement direction (SZ direction) of the optical sheet 20 coincides with the first proximity arrangement direction DL1. In this case, the regions PB1, PB2, PB3, and PB4 shown in FIG. 10 can be virtually divided by a straight line drawn in a direction along a specific arrangement direction. In the figure, the portion other than the regions shown as regions PB1, PB2, PB3, and PB4 is a repetition of regions PB1, PB2, PB3, and PB4. The ratio of the widths of these regions is PB1: PB2: PB3: PB4 = 15: 15: 13: 15. Therefore, in the example of FIG. 10, the area ratio of the region including the pixels = (13 + 15) / (15 + 13 + 15 + 15) = 48%.
Similarly, when the area ratio of the region including the pixels is obtained in other directions, it is 64% in the second proximity arrangement direction DL2 and 100% in the third proximity arrangement direction DL3 to the seventh proximity arrangement direction DL7. Become.
By arranging the optical sheet 20 so that the area ratio of the area including the pixels is 80% or more or 100% in this way, a clear image can be displayed to the observer and the image light can be displayed. It is possible to prevent the non-image area F2 of the image source 11 from being visually recognized due to the slight diffusion of L.

Further, it is desirable that the optical sheet 20 is arranged so as to include pixels of different colors in the direction along the specific arrangement direction. This is because if the directions are only the pixels of the same color, the lines of the same color will be diffused and the appearance will not be good.

Furthermore, among the center distances between pixels in any direction from the third proximity arrangement direction to the seventh proximity arrangement direction, the center distance in the direction corresponding to the specific arrangement direction is the pixel in the first proximity arrangement direction. It is desirable that it is within 7 times the center distance between the pixel and the pixel. In FIG. 8, the distance between the pixel centers is also indicated by a reference numeral. Explaining by the example in FIG. 8, it is as follows.
1st proximity arrangement direction DL1: CD1 / CD1 = 1.0
Second proximity arrangement direction DL2: CD2 / CD1 = 1.4
Third proximity arrangement direction DL3: CD3 / CD1 = 2.2
4th proximity arrangement direction DL4: CD4 / CD1 = 3.2
Fifth proximity arrangement direction DL5: CD5 / CD1 = 3.6
6th proximity arrangement direction DL6: CD6 / CD1 = 4.1
7th proximity arrangement direction DL7: CD7 / CD1 = 5.0
Eighth proximity arrangement direction DL8: CD8 / CD1 = 5.1
9th proximity arrangement direction DL9: CD9 / CD1 = 5.4
As described above, in the present embodiment, the condition that the above-mentioned direction is within 7 times is satisfied in any direction.
When the center distance in the direction corresponding to the specific arrangement direction exceeds 7 times the center distance between the pixels in the first proximity arrangement direction, the diffusion action of the optical sheet 20 becomes insufficient and the adjacent pixels are reached. This is because the non-image area F2 between the two areas may be visually recognized, and on the other hand, if the diffusion action is enhanced, a clear image cannot be obtained.

Next, the light diffusing action of the optical sheet 20 will be described from the viewpoint of the spreading of the light emitted by the pixels.
The light emitted by one pixel provided in the image source 11 is expanded in the range of the light (hereinafter referred to as a light emitting area) mainly by the diffusing action of the optical sheet 20. As described above, since the direction in which the optical sheet 20 diffuses light has directivity, the direction in which the light emitting area expands due to the diffusion action of the optical sheet 20 also has directivity.
FIG. 13 is a diagram illustrating a light emitting area of one pixel. FIG. 13A is an observation image obtained by magnifying the image displayed by the image source 11 with a digital microscope or the like without using the lens 12 and the optical sheet 20, and shows the state of the light emitted by one pixel. .. The figures shown in FIGS. 13 (b) and 13 (c) are observation images obtained by magnifying an image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination without using the lens 12 with a digital microscope or the like. Yes, it shows the state of the light emitted by one pixel.

When the light emitted from the pixel does not pass through the optical sheet 20 or the like, as shown in FIG. 13A, the light emitting area EA0 is observed as a shape close to the shape of the light emitting portion of the pixel (for example, a circular shape). Will be done. Then, due to the diffusing action of the optical sheet 20, the light emitted from the pixels is most widely spread in a specific arrangement direction (SZ direction, arrangement direction of the unit shape 21a), as shown in FIG. 13 (b). In addition, the light emitting area EA is observed as the most widespread shape in one direction along a specific arrangement direction. The direction in which the light emitting area EA is widened is equal to the above-mentioned direction in which the diffusion is the largest.

Further, as the distance between the optical sheet 20 and the pixels (display layer 11e) of the image source 11 is shorter, it is preferable that the arrangement pitch P1 of the unit shape 21a of the optical sheet 20 is smaller from the viewpoint of obtaining an appropriate diffusion action. Therefore, when the optical sheet 20 is arranged close to the pixels, such as by stacking the optical sheet 20 on the display surface 11a of the image source 11, the optical sheet 20 is separated from the optical sheet 20 as compared with the case where the optical sheet 20 is arranged away from the image source 11. In the emitted light of, the ratio of the amount of light emitted by being diffused by diffraction in the unit shape 21a becomes large.
In this case, as shown in FIG. 13 (c), the light emitting area EA is in a state of being most widened in one direction along a specific arrangement direction (SZ direction), and is a region (bright) in which the amount of light generated by diffraction is large. Regions) are observed in multiple granules.

FIG. 14 is a diagram illustrating the spread width W of the light emitting area EA. Each graph shown in FIG. 14 shows the distribution of the amount of light in the direction (SZ direction) in which the light emitting area EA is most widened, the vertical axis shows the amount of light, and the horizontal axis shows the position in the SZ direction.
The graph shown in FIG. 14A is an example of the distribution of the amount of light in one light emitting area EA0 in an observation image obtained by magnifying the image displayed by the image source 11 with a digital microscope or the like without using the lens 12 and the optical sheet 20. Shows. Each graph shown in FIGS. 14 (b) and 14 (c) is an observation image obtained by magnifying an image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination without using the lens 12 with a digital microscope or the like. An example of the distribution of the amount of light in one light emitting area EA is shown. The graph shown in FIG. 14B is an example in which the ratio of the diffusing action due to refraction at the interface of the unit shape 21a is high in the light emitted from the optical sheet 20 and is shown in FIG. 14C. Is an example of a case where the ratio of the diffusing action due to diffraction by the unit shape 21a is high in the light emitted from the optical sheet 20.

As shown in FIGS. 14 (b) and 14 (c), the spread width W of the light emitting area EA of one pixel is an optical sheet in an image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination. It is defined as the interval between the two most distant points t1 and t2, which is 1/5 of the maximum value of the amount of light in the direction (SZ direction) in which the light emitting area EA is most greatly expanded by 20.
Further, the spread width W is 0.5 times or more and 5 times the center distance between the pixels closest to each other (that is, the center distance between the pixels in the first proximity arrangement direction DL1) in the above-mentioned video. The following is preferable.

In the image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination, a value that is 1/5 of the maximum value or the maximum value of the light emission area EA, the positions of the two points t1 and t2, and the like. The distance between the two points t1 and t2 is the video signal (coordinate information and signal intensity in the image) in the observation image of the light emitting area EA taken by magnifying the image with a digital microscope or the like and magnifying it with a CCD camera or the like. Therefore, it is possible to detect and calculate the correlation between the position and the brightness in the light emitting area EA.
Further, the center distance between the pixels in the first proximity arrangement direction DL1 in the image displayed in the state where the image source 11 and the optical sheet 20 are arranged in combination is the image in a state where the lens 12 and the optical sheet 20 are not used. It can be calculated from the observation image obtained by magnifying the image displayed by the source 11 in the same manner. The center distance between the pixels in the first proximity arrangement direction DL1 is also obtained from an observation image obtained by similarly magnifying an image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination. Although it can be calculated, in order to ensure accuracy, it is desirable to calculate from the observation image obtained by similarly magnifying and capturing the image displayed by the image source 11.

When the spread width W is less than the above range, the non-image area becomes large between the light emitting areas of adjacent pixels, and the non-image area is easily visible in the use state of the display device 1, which is not preferable. Further, when the spread width W is larger than the above range, the light emitting areas of adjacent pixels are greatly overlapped, the image is blurred, and the sharpness of the image is significantly lowered, which is not preferable. Therefore, it is desirable that the spread width W is in the above range.

Further, the spread width W is the direction in which the light emitting area EA has the largest spread (of the optical sheet 20) in the image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination while satisfying the above range. It is preferably equal to or less than the center distance between the pixels arranged closest to each other in the specific arrangement direction (SZ direction).
When the spread width W is larger than the center distance between the pixels arranged closest to each other in the direction in which the spread of the light emitting area EA is the largest (the specific arrangement direction of the optical sheet 20, the SZ direction), the adjacent pixels are adjacent to each other. The light emitting areas of the matching pixels (the range in which the light emitted by the adjacent pixels spreads) overlap, which may cause blurring of the image. Therefore, it is preferable that the spread width W further satisfies the above range.

Further, the direction in which the light emitting area EA spreads most is equal to the specific arrangement direction (SZ direction) of the optical sheet 20, and as described above, 5 with respect to the first proximity arrangement direction DL1 and the second proximity arrangement direction DL2. It is desirable that the optical sheet 20 is arranged so as to form an angle of degrees or more.
By arranging the optical sheet 20 in this way, it is possible to avoid an inappropriate arrangement in which the non-image area F2 is visually recognized in a streak pattern as in FIG. 10 described above, and a clear image is displayed to the observer. It is possible to prevent the non-image region F2 of the image source 11 from being visually recognized due to the slight diffusion of the image light L.

Further, the direction in which the light emitting area EA spreads most is equal to the specific arrangement direction (SZ direction) of the optical sheet 20, and as described above, the third proximity arrangement direction DL3 or the fourth proximity arrangement direction DL4, or , 5th proximity arrangement direction DL5, 6th proximity arrangement direction DL6, 7th proximity arrangement direction DL7, 8th proximity arrangement direction DL8, 9th proximity arrangement direction DL9 within 2 degrees. It is desirable to have and be placed.
By arranging the optical sheet 20 in this way, a clear image can be displayed to the observer, and the non-image area F2 of the image source 11 is suppressed from being visually recognized by the minute diffusion of the image light L. be able to.

In the display device 1 including the image source 11 in which the pixel arrangement is a diamond pentile arrangement, the optical sheet 20 is arranged by changing the angle δ indicating a specific arrangement direction (arrangement direction of the unit shape 21a, SZ direction). When the appearance of the observed image is visually evaluated, it is preferable to arrange the optical sheet 20 in the range of the angle δ of 8 degrees to 25 degrees, and the angle δ is 8 degrees to 18 degrees, as shown in FIG. It is more desirable to arrange in the range of degrees.

Then, the display device 1 arranges the optical sheet 20 so that the angle δ satisfies the above range, and further, in the image displayed in a state where the image source 11 and the optical sheet 20 are arranged in combination, the light emitting area. By setting the spread width W of the EA to 0.5 times or more and 5 times or less the center distance between the pixels in the first proximity arrangement direction DL1, the non-video area F2 is visually recognized and the pixel area G1 (pixel) becomes independent. It is possible to suppress the appearance of the image and display a good image.
Further, in the above image, the spread width W is set to be equal to or less than the center distance between the pixels closest to each other in the direction in which the spread of the light emitting area EA is the largest (the specific arrangement direction of the optical sheet 20, the SZ direction). As a result, the display device 1 can further enhance the above-mentioned effect and can display a good image with less blur.

Here, as an example, the direction (SZ direction) in which the spread width W due to the diffusion action of the optical sheet 20 satisfies the above-mentioned preferable range and the light emitting area EA is most widened by the optical sheet 20 is the fifth proximity arrangement direction DL5. When the display device 1 was prepared and observed at the observation position (the position of the observer's eye E when the display device 1 was used and the focal point of the image light L by the lens 12), a non-image area was observed. It was possible to suppress the visibility of F2, suppress the appearance of the pixel region G1 (pixels) independently, and visually recognize a good image.
Further, in this display device 1, when the spread width W due to the diffusion action of the optical sheet 20 is less than the preferable range and the spread width W is larger than the preferable range and observed at the observation position, the non-image region F2 is visually recognized. The pixel region G1 (pixel) was observed independently, or the image was blurred and the sharpness was significantly reduced, so that a good image could not be visually recognized.

Next, the spread width W satisfies the preferable range as described above, and the direction in which the light is most spread by the third proximity arrangement direction DL3, the seventh proximity arrangement direction DL7, and the optical sheet 20 (the arrangement direction (SZ direction) of the unit shape 21a). )) Was prepared, and when the image was visually recognized at the observation position, a similarly good image was visually recognized.
Further, in these display devices 1, those in which the spread width W due to the diffusion action of the optical sheet 20 is less than the preferable range and those in which the spread width W is larger than the preferable range are prepared, and the image displayed at the observation position is visually recognized as described above. However, the non-image area F2 is visually recognized, and the pixel area G1 (pixel) is observed independently, or the image is blurred and the sharpness is significantly reduced, so that a good image is visually recognized. Couldn't.

FIG. 12 is a diagram illustrating another fixed form of the optical sheet 20. FIG. 12 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, and may have, for example, an irregular shape connecting between the left and right regions as shown in FIG. 12 (a). Further, the optical sheet 20 may have a rectangular shape as shown in FIG. 12 (b). With such a shape, it becomes easy to arrange the optical sheet 20 at an inclination of a predetermined angle δ 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. 12, since the shape is symmetrical, an index indicating the direction of the optical sheet 20 may be provided or the shape may be asymmetrical in order to prevent mistakes during assembly.

As described above, according to the present embodiment, 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 display the pixel region G1. Can not be seen independently, and the non-image region F2 caused by the non-pixel region G2 of the image source 11 can be prevented from being visually recognized by the observer.

(Deformed form)
Not limited to the embodiments described above, various modifications and changes are possible, and these are also within the scope of the present invention.

(1) In the embodiment, the unit shape 21a has been described with reference to an example in which the cross-sectional shape is an arc-shaped lenticular lens shape. Not limited to this, for example, the unit shape may have a triangular cross-sectional shape, a polygonal shape, or a shape composed of a curve other than an arc shape.

(2) In the embodiment, an example in which the optical sheet 20 is arranged with a gap between the optical sheet 20 and the image source 11 has been described. Not limited to this, for example, the optical sheet 20 may be arranged without providing a gap between the optical sheet 20 and the image source 11. In this case, for example, the gap may be filled with a filler that reduces the difference in refractive index.

(3) In the embodiment, the optical sheet 20 has been described with reference to an example in which the second optical layer 22 is laminated on the first optical layer 21 provided with the unit shape 21a. Not limited to this, for example, the second optical layer 22 may be omitted.

(4) In the embodiment, the image source 11 may be fixed to the display device 1 in advance and may be non-detachable.

(5) In the embodiment, an example in which the optical sheet 20 has only a unit shape of a lenticular lens shape extending in one direction has been described. Not limited to this, for example, two different unit shapes that are orthogonal to each other may be provided in the same optical sheet, or may be separately used in an overlapping manner.

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 each of the embodiments described above.

1 Display device 11 Image source 11a Display surface 11b Transparent substrate 11c Transparent electrode 11d Organic hole transport layer 11e Display layer 11f Organic electron transport layer 11g Metal electrode 12 Lens 12A Lens 12B Lens 12a Reflection suppression layer 20 Optical sheet 20A Optical sheet 20B Optical Sheet 20a Convex part 21 First optical layer 21a Unit shape 22 Second optical layer 22a Observer side surface 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 Recess 331 Opening EA Luminous area

Claims (18)

A head-mounted display device that is attached to the observer's head and displays an image in front of the observer's eyes.
An image source that emits image light and
Two convex lenses corresponding to the left and right eyes of the observer and emitting the image light to the observer side, and
An optical sheet arranged between the image source and the convex lens and diffusing the image light,
Equipped with
The optical sheet has directivity with respect to the diffusion of light, and has the direction in which the diffusion of the image light is the largest in the direction in the sheet surface of the optical sheet.
The image source has two regions for displaying images corresponding to the left and right eyes of the observer, and the convex lens is arranged so as to correspond to the two regions, whereby the display device can be used. , Displaying images corresponding to each of the observer's left and right eyes independently,
A display device characterized by. In the display device according to claim 1,
The image source is configured by arranging a plurality of pixels side by side.
The direction in which the center distance between the pixels is closest is defined as the first proximity arrangement direction.
The direction different from the first proximity arrangement direction and the direction in which the center distance between the pixels is close to each other next to the first proximity arrangement direction is defined as the second proximity arrangement direction.
The direction in which the diffusion of the image light is the largest is that the images are arranged at an angle of 5 degrees or more with respect to the first proximity arrangement direction and the second proximity arrangement direction.
A display device characterized by. In the display device according to claim 2,
Either one of the first proximity arrangement direction and the second proximity arrangement direction is a direction forming 45 degrees with respect to the vertical direction or the horizontal direction of the screen of the image source.
A display device characterized by. In the display device according to claim 2 or claim 3.
For the pixels arranged in the video source
The direction different from the first proximity arrangement direction and the second proximity arrangement direction, and the direction in which the center distance between the pixels is close to each other next to the second proximity arrangement direction is defined as the third proximity arrangement direction. Prescribe and
Let N be an integer of 3 or more, and hereinafter, the direction is different from the first proximity arrangement direction to the Nth proximity arrangement direction, and the center distance between the pixels is close to each other next to the Nth proximity arrangement direction. The direction in which it is present is defined as the first (N + 1) proximity arrangement direction.
The direction in which the diffusion of the image light is the largest is arranged at an angle within 2 degrees with respect to the Nth proximity arrangement direction.
Of the center distances between pixels in the Nth proximity arrangement direction, the center distance in the direction corresponding to the direction in which the diffusion of video light is maximum is the center distance between pixels in the first proximity arrangement direction. Must be within 7 times
A display device characterized by. In the display device according to claim 4,
The direction in which the diffusion of the image light is the largest is the same direction as the Nth proximity arrangement direction.
A display device characterized by. In the display device according to any one of claims 2 to 5.
The direction in which the diffusion of the image light is the largest is arranged at an angle of 10 degrees or more with respect to the first proximity arrangement direction, and an angle of 5 degrees or more with respect to the second proximity arrangement direction. Being placed with
A display device characterized by. The display device according to any one of claims 2 to 6.
A straight line drawn in the direction along the direction in which the diffusion of the image light is maximum, and a straight line passing through the outermost diameter portion of the pixel is drawn to form a region including the pixel and a region not including the pixel. When the video source is virtually divided, the direction in which the video light is diffused to the maximum is provided so that the area ratio of the region including the pixels is 80% or more.
A display device characterized by. In the display device according to claim 7,
The direction in which the diffusion of the image light is the largest is provided so that the area ratio of the area including the pixels is 100%.
A display device characterized by. The display device according to any one of claims 2 to 8.
The image source is configured by arranging the pixels of a plurality of colors side by side.
Pixels of different colors are included and arranged in the direction along the direction in which the diffusion of the image light is maximum.
A display device characterized by. In the display device according to any one of claims 1 to 9.
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 optical sheet diffuses light in the arrangement direction of the unit shape.
The unit shape extends in a first direction in the sheet surface orthogonal to the thickness direction of the optical sheet, and the second direction orthogonal to the first direction in the sheet surface is the specific arrangement direction. Arranged as,
The direction in which the diffusion of the image light is the largest is the specific arrangement direction.
A display device characterized by. In the display device according to claim 10,
The angle δ formed by the specific arrangement direction with respect to the vertical direction of the screen of the image source is 8 ° or more and 25 ° or less.
A display device characterized by. In the display device according to claim 10 or 11.
The optical sheet is composed of two or more different layers, and the unit shape is configured at the interface of the different layers.
A display device characterized by. The display device according to any one of claims 1 to 12.
Two optical sheets are arranged so as to correspond to the two regions.
A display device characterized by. In the display device according to any one of claims 1 to 13.
In the optical sheet, the diffusion angle in the direction in which the diffusion of the image light is the largest is 10 times or more the diffusion angle in the direction in which the diffusion of the image light is the smallest.
A display device characterized by. The display device according to any one of claims 1 to 14.
The gap between the optical sheet and the image source shall be filled with a filler that reduces the difference in refractive index.
A display device characterized by. The display device according to any one of claims 1 to 15.
The optical sheet includes at least one layer of a reflection suppression layer, a hard coat layer, an antistatic layer, and an antifouling layer.
A display device characterized by. The display device according to any one of claims 1 to 16.
The image source has a ratio of the light emitting area in the image display area of 50% or less.
A display device characterized by. The display device according to any one of claims 1 to 17.
The pixel arrangement of the image source is a diamond pen tile arrangement.
A display device characterized by.

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