JP2018084741A - Display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a display device capable of suppressing visual recognition of a non-image region caused by a non-pixel region existing between pixel regions of an image source. SOLUTION: A display device 1 includes a video source 11 in which a plurality of pixel regions are arranged and emits video light, a lens 12 that magnifies the video light and emits the video light to an observer side, and a video source 11 and a lens 12. The optical sheet 20 includes an optical sheet 20 arranged between the lenses or on the observer side of the lens 12, and the optical sheet 20 has two or more optical layers laminated and has a convex or concave shape at the interface between adjacent optical layers. When the distance between the optical sheet and the display layer of the image source is L, and the pixel arrangement pitch in which the pixel regions are arranged is P, the average diffusion of the optical sheet is formed. The angle θave satisfies 20 ≦ θave × L / P ≦ 40. [Selection diagram] Fig. 1

Description

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

2. Description of the Related Art Conventionally, there has been proposed a head-mounted display device, so-called head mounted display (HMD), that allows an observer to observe an image from an image source such as an LCD (Liquid Crystal Display) or an organic EL display through an optical system. (For example, patent document 1). Such a head-mounted display device enlarges image light projected from an image source by an optical system such as a lens and displays a clear image to an observer.
A video source used in such a display device is provided with a plurality of pixel regions constituting a video and non-pixel regions that are provided between the pixel regions and do not contribute to video display. When the image light emitted from such an image source is enlarged by a lens, not only the image constituted by the pixel area, but also the non-image area caused by the non-pixel area is enlarged, and only the image is obtained. In some cases, the non-video area may be visually recognized by the observer, which may hinder the display of a clear video.

Special table 2011-509417 gazette

  The subject of this invention is providing the display apparatus which can suppress that the non-video area | region resulting from the non-pixel area | region which exists between the pixel areas of a video source becomes visible.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

と定義し、前記光学シートと前記映像源の表示層との間の距離をＬとし、前記画素領域が配列されている画素配列ピッチをＰとしたとき、２０≦θａｖｅ×Ｌ／Ｐ≦４０を満たす表示装置（１）である。 According to a first aspect of the present invention, there is provided an image source (11) in which a plurality of pixel regions are arranged to emit image light (V);
A lens (12) that magnifies and emits the image light (V) to the observer side, between the image source (11) and the lens (12), or on the observer side of the lens (12). An optical sheet (20) to be disposed, wherein the optical sheet (20) is formed by laminating two or more optical layers (21, 22, 23), and adjacent optical layers (21, 22, 23). A plurality of convex or concave unit shapes (21a, 23a) are formed at the interface between the lens (12) and the optical sheet (20), where the luminance at the diffusion angle θ is I (θ). When the distance between them is K and the effective radius of the lens (12) is R, the average diffusion angle θave of the optical sheet (20) is

When the distance between the optical sheet and the display layer of the video source is L and the pixel arrangement pitch in which the pixel regions are arranged is P, 20 ≦ θave × L / P ≦ 40 It is the display device (1) that satisfies.

  A second invention is the display device (1) according to the first invention, wherein the display device (1) satisfies 23 ≦ θave × L / P ≦ 35.

  According to a third aspect of the present invention, in the display device (1) according to the first or second aspect, the unit shape (21a, 23a) is a convex shape, and the thickness direction of the optical sheet (20) Extending in a first direction in the sheet surface orthogonal to the first surface, arranged in a second direction orthogonal to the first direction in the sheet surface, and parallel to the thickness direction of the optical sheet (20). The display device (1) is characterized in that a cross-sectional shape in a cross section parallel to the second direction is formed in a substantially arc shape.

  According to a fourth invention, in the display device (1) according to any one of the first to third inventions, the unit shape (21a, 23a) is orthogonal to the thickness direction of the optical sheet (20). Extending in a first direction in the sheet surface, arranged in a second direction orthogonal to the first direction in the sheet surface, parallel to the thickness direction of the optical sheet (20), and The display device (1) is characterized in that a cross-sectional shape in a cross section parallel to the second direction is formed in a substantially triangular shape.

  According to a fifth invention, in the display device (1) according to any one of the first to fourth inventions, the unit shape (21a) is a convex shape, and the optical sheet (20) The display device (1) is characterized by being formed in a substantially quadrangular pyramid shape arranged along a sheet surface orthogonal to the thickness direction.

  According to a sixth invention, in the display device (1) according to any one of the first to fifth inventions, the optical sheet (20) includes three or more optical layers (21, 22, 23). The unit shape (21a, 23a) provided at each interface between the adjacent optical layers (21, 22, 23) has an extending direction in the sheet surface direction of the optical sheet (20). It is the display apparatus (1) characterized by crossing seeing from the thickness direction.

  According to the present invention, the display device can suppress the non-video area caused by the non-pixel area existing between the pixel areas of the video source from being visually recognized.

It is a figure explaining the head mounting type display apparatus 1 of this embodiment. It is a figure explaining the detail of the optical sheet 20 used for the display apparatus 1 of this embodiment. It is a figure which shows the example of the image displayed by the display apparatus 1 of this embodiment. It is a figure explaining the display apparatus 5 of a comparative example. It is a figure which shows an example of the relationship between the brightness | luminance and diffusion angle of the optical sheet 20 used for the display apparatus 1 of this embodiment. It is a figure which shows the distance K, the distance L, and the effective radius R of the lens 12. It is a figure which shows the relationship between the appearance of the optical sheet 20, and (theta) ave * L / P. It is a figure explaining the detail of the other form of the optical sheet 20 used for the display apparatus 1 of this embodiment. It is a figure explaining the detail of the other form of the optical sheet 20 used for the display apparatus 1 of this embodiment. It is a figure which shows the relationship between the brightness | luminance and diffusion angle of the optical sheet 20 of the other form shown in FIG.8 and FIG.9. It is a figure which shows another form of the unit shape 21a provided in the optical sheet 20 shown in FIG.8 and FIG.9. It is a figure explaining another form of the optical sheet 20 shown in FIG.8 and FIG.9. It is a figure explaining another form of the optical sheet 20 shown in FIG.8 and FIG.9. It is a figure explaining the other form of the optical sheet 20 used for the display apparatus 1 of this embodiment. It is a figure explaining another form of the optical sheet 20 shown in FIG. It is a figure explaining another form of the optical sheet 20 shown in FIG. It is a figure explaining another form of the optical sheet 20 shown in FIG. It is a figure explaining the other form of the head-mounted display apparatus 1 of this embodiment. It is a figure explaining the optical sheet 120 of a deformation | transformation form.

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

(Embodiment)
FIG. 1 is a diagram illustrating a head-mounted display device 1 according to this embodiment. FIG. 1 is a view of the display device 1 as viewed from above in the vertical direction.
FIG. 2 is a diagram illustrating details of the optical sheet 20 used in the display device 1 of the present embodiment. 2A is a cross-sectional view in a cross section parallel to the horizontal plane (XY plane) of the optical sheet 20, and FIG. 2B is a cross-sectional view of a portion b in FIG. 2A. FIG. 2C is a diagram showing details of the portion c in FIG. 2A, and FIG. 2D is a diagram showing details of the portion d in FIG. 2B.
FIG. 3 is a diagram illustrating an example of an image displayed by the display device 1 of the present embodiment.
FIG. 4 is a diagram illustrating a display device 5 of a comparative example. FIG. 4A is a diagram for explaining the configuration of the display device 5 of the comparative example, and corresponds to FIG. 4A shows only the video source 51 and the lens 52 as the display device 5 for easy understanding. FIG. 4B is a diagram illustrating an example of an image displayed by the display device 5 of the comparative example.

  In the drawings shown below including FIG. 1 and the following description, the vertical direction (vertical direction) is set to the Z direction in a state where the viewer wears the display device 1 on the head for easy understanding. Let the horizontal direction be the X direction and the Y direction. Moreover, among this horizontal direction, let the thickness direction of the optical sheet 20 be Y direction, and let the left-right direction orthogonal to the thickness direction be X direction. The −Y side in the Y direction is the observer side, and the + Y side is the video source side (back side).

The display device 1 is a so-called head mounted display (HMD) that is attached to the head of an observer and displays an image in front of the eyes of the observer. As shown in FIG. 1, the head-mounted display device 1 according to the present embodiment includes an image source 11, a lens 12, and an optical sheet 20 inside a housing 30. By wearing the head 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 through the optical sheet 20 and the lens 12.
In FIG. 1, the display device 1 will be described with reference to an example in which an image is displayed on the observer's eyes E1 and E2. However, the display device 1 is not limited to this example. It is good also as a form arrange | positioned with respect to the eye E1, and displaying an image | video with respect to the eye E1.

The housing 30 is a rectangular box-shaped housing that is horizontally long in the left-right direction, and a holding unit 31 that holds the image source 11, a holding unit 32 that holds the optical sheet 20 (20 </ b> A, 20 </ b> B), and a lens inside thereof. 12 (12A, 12B) is provided. The housing 30 can be attached to the observer's head with, for example, a belt (not shown).
The holding unit 31 is a member that holds the image source 11, and a position corresponding to the eye E (E 1, E 2) and the lens 12 (12 A, 12 B) of the observer on the display surface 11 a side of the image source 11. Have openings 311 (311A, 311B). In the present embodiment, the video source 11 is detachably held by the holding unit 31 (that is, the display device 1). The video light V emitted from the video source 11 enters the lens 12 (12A, 12B) through the opening 311 (311A, 311B).

The holding unit 32 is a member that is positioned closer to the observer side (−Y side) than the holding unit 31 and the image source 11 and holds the optical sheet 20. In the holding part 32, the optical sheet 20 (20A, 20B) is fitted and held in the opening part 321 (321A, 321B) provided at a position corresponding to the opening part 311 (311A, 311B).
The holding unit 32 and the above-described holding unit 31 are integrally movable 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 adjustment is possible) according to the visual acuity of the observer. In addition, not only this but the holding | maintenance part 31 and the holding | maintenance part 32 are good also as a form by which the position of the Y direction was fixed.
The holding unit 33 is a member that is positioned closer to the observer side (−Y side) than the holding unit 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 located in the opening 331 (331A, 331B). It is fitted and held.

The video source 11 is a micro display that emits video light V 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 may be used. it can. As the video source 11 of this embodiment, for example, an organic EL display having a diagonal of 5 inches is used.
The video source 11 is held by the holding unit 31 such that the display surface 11a is on the viewer side (−Y side).
In the present embodiment, the display device 1 has an example in which one video source 11 is provided. It is good also as a form provided with two video sources which do.

The lenses 12 (12A, 12B) are convex lenses that magnify the image light V emitted from the image source 11 and emit it to the viewer side. In the present embodiment, the image source 11 and the optical sheet 20 (20A, 20B) are arranged closer to the viewer (−Y side). The lens 12 is made of glass or resin with high translucency.
A reflection suppression layer 12 a is formed on the surface of the lens 12 on the image source side (back side, + Y side). The antireflection layer 12a is coated with a material having a general antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), fluorine optical coating agent, etc.) with a predetermined film thickness. The image source of the lens 12 may be provided with a layer exhibiting a reflection suppressing function by having a moth-eye structure having a minute concavo-convex shape formed at a pitch smaller than the wavelength of light on the surface on the light incident side. Alternatively, they may be integrally laminated on the side.

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

As shown in FIG. 1, the optical sheet 20 is disposed between the video source 11 and the lens 12. The lens 12 is a light-transmitting sheet having a diffusion function for slightly diffusing the image light V emitted from the image source 11.
In the present embodiment, lenses 12A and 12B and optical sheets 20A and 20B are provided corresponding to the observer's eyes E1 and E2, respectively. However, the present invention is not limited to this. For example, one optical sheet 20 that is large enough to cover the area of the lenses 12A and 12B may be arranged on the image source side (back side, -Y side) from the lens 12. Good.

Conventionally, the head-mounted display device 5 (hereinafter referred to as the comparative display device 5) that is mainly used is not provided with the optical sheet 20 as shown in FIG. 4A. Yes, the image light V emitted from the image source 51 is magnified by the lens 52 and the image is displayed to the observer.
A display such as an organic EL used for the video source 51 and the video source 11 has a plurality of pixel areas G1 that form an image on the display portion thereof, and does not contribute to the formation of an image between the pixel areas G1. A non-pixel region G2 is provided. Therefore, in the display device 5 of the comparative example, when the video displayed by the video light V emitted from the video source 51 is enlarged through the lens 52, as shown in FIG. In addition to the image F1 caused by the above, the non-image region F2 caused by the non-pixel region G2 is also enlarged. In addition, the non-video area F2 is also clearly visible to the observer, which may hinder clear video display.

  On the other hand, in the display device 1 of the present embodiment, by providing the optical sheet 20 described above, the image light emitted from the image source 11 is slightly diffused, and the diffused image is displayed as shown in FIG. It is possible to suppress the non-image area F2 caused by the non-pixel area G2 from being visually recognized by the observer.

As shown in FIG. 2, the optical sheet 20 of the present embodiment has a reflection suppression layer 24, a first optical layer 21, a second optical layer 22, and a third optical layer in order from the image source side (back side, + Y side). 23 are stacked. In the optical sheet 20, a plurality of unit shapes 21a and unit shapes 23a are formed on the interface between the first optical layer 21 and the second optical layer 22 and on the interface between the second optical layer 22 and the third optical layer 23, respectively. Yes.
The first optical layer 21 is a layer that is located on the image source side (+ Y side) with respect to the second optical layer 22 and the third optical layer 23 in the thickness direction (Y direction) of the optical sheet 20 and has optical transparency. is there. The image source side surface of the first optical layer 21 is formed substantially flat. A plurality of convex unit shapes 21 a are formed on the surface of the first optical layer 21 on the viewer side (−Y side) as shown in FIG. The unit shape 21a is convex on the observer side (−Y side).
The unit shapes 21a extend in the up-down direction (Z direction) and are arranged in the left-right direction (X direction) orthogonal to the extending direction so as to follow the surface on the viewer side of the first optical layer 21. ing. The unit shape 21a is a lenticular lens shape in which a cross-sectional shape on a plane (XY plane) parallel to the left-right direction and the thickness direction is formed in a substantially arc shape. 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 third optical layer 23 is a layer having optical transparency located on the most observer side (−Y side) of the optical sheet 20. The surface on the observer side of the third optical layer 23 is a surface from which image light transmitted through the optical sheet 20 is emitted, and is formed to be substantially flat. On the image source side (+ Y side) surface of the third optical layer 23, as shown in FIG. 2B, a plurality of convex unit shapes 23a are formed. The unit shape 23a is convex toward the video source side (+ Y side).
A plurality of unit shapes 23 a are arranged in the vertical direction (Z direction) perpendicular to the extending direction, extending in the left-right direction (X direction) along the image source side surface of the third optical layer 23. The cross-sectional shape of the surface (YZ plane) parallel to the vertical direction and the thickness direction is a lenticular lens shape formed in a substantially arc shape.

When viewed from the thickness direction of the optical sheet 20 (the normal direction of the sheet surface, the Y direction), the extending direction (X direction) of the unit shape 23a provided in the third optical layer 23 and the first optical layer 21 are provided. The unit shape 21a intersects (orthogonal) with the extending direction (Z direction).
Further, when viewed from the thickness direction of the optical sheet 20 (the normal direction of the sheet surface, the Y direction), the arrangement direction (X direction) of the unit shapes 21a and the arrangement direction (Z direction) of the unit shapes 23a intersect (orthogonal). )doing.

  The second optical layer 22 is a light transmissive layer provided between the first optical layer 21 and the third optical layer 23. Both surfaces of the second optical layer 22 are arranged such that the surface on the unit shape 21a side of the first optical layer 21 and the surface on the unit shape 23a side of the third optical layer 23 face each other.

As described above, the optical sheet 20 suppresses the observer from visually recognizing the non-image area F2 caused by the non-pixel area G2 due to the action of diffusing the image light V. If the diffusing action by the optical sheet 20 is too strong, the image light V is diffused more than necessary, and the quality of the image is deteriorated. On the other hand, if the diffusion action by the optical sheet 20 is too weak, the non-image area F2 is visually recognized by the observer. Therefore, the optical sheet 20 must have an appropriate diffusing action.
Since the optical sheet 20 diffuses the image light V from the image source 11 and observes it by magnifying it with the lens 12, the component of the light diffused in the range actually observed by the lens 12 is important.

FIG. 5 is a diagram illustrating an example of the relationship between the luminance and the diffusion angle of the optical sheet 20 used in the display device 1 of the present embodiment.
Even if the relationship between the brightness of the light passing through the optical sheet 20 and the diffusion angle is as shown in FIG. 5, for example, the components that reach the observer through the lens 12 are −φ to + φ in the figure. Suppose that it is a component of the range. If it does so, if the component of the light diffused in this range is used as a parameter | index of the diffusion degree of the optical sheet 20, an appropriate diffusion effect as the optical sheet 20 can be evaluated. In addition, if the pixel arrangement pitch in which the pixel regions of the video source 11 are arranged changes, the degree of necessary diffusion action also changes, so this pixel arrangement pitch is also an important parameter. Furthermore, if the distance between the lens 12 and the optical sheet 20 changes, the effect of the optical sheet 20 diffusing the image light V also changes.
Therefore, when the luminance at the diffusion angle θ is I (θ), the distance between the lens 12 and the optical sheet 20 is K, and the effective radius of the lens 12 is R, the range of −φ to + φ in FIG. The average diffusion angle θave of the optical sheet 20 with respect to the components,

  , L is the distance between the optical sheet and the display layer of the video source, P is the pixel arrangement pitch in which the pixel regions G1 are arranged, and θave × L / P is the video light from the optical sheet 20 This is set as an index indicating the degree of suppressing the non-image area F2 caused by the non-pixel area G2 from being visually recognized by the observer by the action of diffusing V, that is, an index of the blurring degree.

FIG. 6 is a diagram illustrating the distance K, the distance L, and the effective radius R of the lens 12.
The optical sheet 20 is configured by stacking a plurality of layers, and a plurality of lenses can also be used for the lens 12. Therefore, for the distance K between the lens 12 and the optical sheet 20, from the center position between the unit shape 21 a and the unit shape 23 a to the center of the lens 12 (the main point in the case of a single lens). Let K be the distance.
Further, when the image source 11 is an organic EL display, for example, as illustrated in FIG. 6, the transparent substrate 11 b, the transparent electrode 11 c, the organic hole transport layer 11 d, and the organic light emitting layer ( A plurality of layers are laminated such as a display layer 11e, an organic electron transport layer 11f, and a metal electrode 11g. The distance L mentioned above is good to use the distance from the display layer 11e among these layers. This is because the non-pixel region G2 is formed at the position of the display layer 11e. Moreover, the optical sheet 20 is configured by stacking a plurality of layers. Therefore, the position used as the reference for the distance L is preferably a central position between the unit shape 21a and the unit shape 23a.
In the present embodiment, since the optical sheet 20 has a three-layer structure, there are two refractive index interfaces, and two types of unit shapes are arranged, the reference positions of the distance K and the distance L are as described above. The central position between the unit shape 21a and the unit shape 23a was set. However, this reference position should be changed and applied according to the configuration of the unit shape. For example, when the optical sheet has a two-layer structure, the refractive index interface is one, and there is only one type of unit shape, the position may be the average height of the unit shape. Also, when the refractive index interface is further increased, it is preferable to set the refractive index or the average position of the interfaces.

Next, the result of having created various types of optical sheets 20 by changing various parameters and evaluating the actual appearance is shown in FIG. 7 together with the index: θave × L / P defined as described above.
The pixel arrangement pitch P of the pixel region G1 of the video source 11 used in the display device 1 is 400 to 500 ppi (pixel per inch). In the present embodiment, the pixel arrangement pitch P of the pixel region G1 of the video source 11 is d = 0.0508 mm (500 ppi).
FIG. 7 is a diagram illustrating the relationship between the appearance of the optical sheet 20 and θave × L / P.
In the table of FIG. 7, the optical sheets 20 are shown arranged in the order of θave × L / P. As is clear from FIG. 7, there is a good correlation between the degree of suppressing the non-image area F2 from being visually recognized by the observer and θave × L / P.
And if it is the range of 20 <= thetaave * L / P <= 40, it can be said that it is possible to observe a good image in which the pixels are not seen independently and the video is not excessively blurred.
Further, an optimal image can be observed under more severe conditions, that is, within a range of 23 ≦ θave × L / P ≦ 35.

  Further, the optical sheet 20 of the present embodiment has a refractive index difference between adjacent optical layers, that is, a refractive index difference Δn1 between the first optical layer 21 and the second optical layer 22, and the second optical layer 22 and the third optical layer. The refractive index difference Δn2 of the layer 23 is formed so as to satisfy 0.005 ≦ Δn1 ≦ 0.1 and 0.005 ≦ Δn2 ≦ 0.1, respectively.

  In this way, the range of the value of θave × L / P of the optical sheet 20 and the range of the refractive index differences Δn1 and Δn2 of the layers adjacent to each other with the surface on which the unit shapes 21a and 23a are formed as an interface are defined. Thus, the display device 1 of the present embodiment can slightly diffuse the video light V emitted from the video source 11 in the vertical direction and the left-right 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 being noticeable due to the minute diffusion of the image light V. can do.

  When the refractive index differences Δn1 and Δn2 are less than 0.005, the refractive index difference between the optical layers becomes too small, and it is difficult for the image light to be refracted between the optical layers, so that a sufficient diffusing action cannot be exhibited. Therefore, it is not desirable. On the other hand, when the refractive index differences Δn1 and Δn2 are larger than 0.1, the refraction of light between the optical layers becomes too large, and the image light transmitted through the optical sheet becomes unclear, which is not desirable.

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

When the cross-sectional shape of the unit shape 21a in the XY cross section is formed in an arc shape, as shown in FIG. 2C, the left-right direction (X direction) of the unit shape 21a formed in the first optical layer 21 The unit shape 21a is formed in the range of 0.05 ≦ P1 / R1 ≦ 1.0, where P1 is the arrangement pitch in R and the radius of curvature of the arc-shaped cross-sectional shape in the XY cross section of the unit shape 21a is R1. Is desirable.
Similarly, when the cross-sectional shape in the YZ cross section of the unit shape 23a is formed in an arc shape, as shown in FIG. 2D, the vertical direction of the unit shape 23a formed in the third optical layer 23 (Z Direction), the unit shape 23a is in the range of 0.05 ≦ P2 / R2 ≦ 1.0, where R2 is the radius of curvature of the arc-shaped cross-sectional shape in the YZ cross section of the unit shape 23a. It is desirable to be formed.

Thus, by forming the arrangement pitches P1 and P2 and the curvature radii R1 and R2 of the unit shapes 21a and the unit shapes 23a in the above-described range, the display device 1 efficiently and uniformly distributes the image light emitted from the image source 11. Can be slightly diffused vertically and horizontally.
In the optical sheet 20 of the present embodiment, the unit shape 21a and the unit shape 23a have the same cross-sectional shape, and are formed such that P1 = P2 and R1 = R2.

  In the present embodiment, the arrangement pitch P1 of the unit shapes 21a and the arrangement pitch P2 of the unit shapes 23a preferably satisfy 0.1 mm ≦ P1 ≦ 0.5 mm and 0.1 ≦ P1 ≦ 0.5 mm, respectively. . If the arrangement pitches P1 and P2 are less than 0.1 mm, it is difficult to manufacture the unit shapes 21a and 23a having such dimensions, and a light diffraction phenomenon is likely to occur. This is not preferable because the image becomes unclear. Moreover, when arrangement pitch P1, P2 is larger than 0.5 mm, the line between adjacent unit shapes may be visually recognized, and it is not preferable.

Furthermore, the optical sheet 20 of the present embodiment is provided with a reflection suppressing layer 24 on the image source side (back side, + Y side) of the first optical layer 21.
The reflection suppression layer 24 is, for example, a material having a general antireflection function (for example, magnesium fluoride (MgF ₂ ), silicon dioxide (SiO ₂ ), in the same manner as the reflection suppression layer 12 a provided on the image source side of the lens 12. ₂ ), a fluorine-based optical coating agent, etc.) may be provided by coating with a predetermined film thickness. In addition, when the image source 11 is fixed to the display device and cannot be removed, the moth-eye structure having a minute uneven shape formed at a pitch smaller than the wavelength of the light is provided on the light incident side surface. Thus, a layer exhibiting 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 brightness of the image due to the light incident on the optical sheet 20 being reflected by the image source side surface of the optical sheet 20 toward the image source 11 side. Can be suppressed.
Further, by providing the reflection suppressing 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 travels toward the image source 11 side. It is possible to prevent stray light from being reflected again on the display surface 11a and improve the contrast of the image.

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

Further, as described above, the display device 1 according to the present embodiment has the optical sheet 20 positioned closer to the image source side (+ Y side) than the lens 12, so that the image source 11 can be attached to and detached from the housing 30. 1, the lens 12 is not damaged or soiled by foreign matter such as dust or dust that has entered the housing when the video source 11 is removed from the housing 30. Further, even when the image source side of the optical sheet 20 is contaminated with foreign matter or the like, it is possible to wipe off the unit shape without damaging it.
In particular, the antireflection layer having a moth-eye structure has a high antireflection effect, but it is important that the antireflection layer is provided at a position where an observer's finger or the like cannot be touched because it easily breaks. In the display device 1 of the present embodiment, since the optical sheet 20 is positioned closer to the image source side (+ Y side) than the lens 12, such an antireflection layer is provided on the observer side of the optical sheet 20 or the image source side of the lens 12. And the like, and a higher reflection suppression effect can be obtained, and the contrast and brightness of the image can be improved.

Next, an operation until the video light V emitted from the video source 11 reaches the observer's eyes E (E1, E2) will be described.
As shown in FIG. 1, the image light V emitted from the image source 11 is incident on the image source side (+ Y side) surface of the optical sheet 20 (20A, 20B). Then, the image light V incident on the optical sheet 20 is transmitted through the first optical layer 21, and in the left-right direction (X direction) by the unit shape 21 a at the interface between the first optical layer 21 and the second optical layer 22. It diffuses slightly and passes through the second optical layer 22.
The video light V transmitted through the second optical layer 22 is slightly diffused in the vertical direction (Z direction) by the unit shape 23a formed at the interface between the second optical layer 22 and the third optical layer 23, and the third The light passes through the optical layer 23 and is emitted from the surface on the viewer side (−Y side) of the optical sheet 20.
The video light V transmitted through the optical sheet 20 enters the lens 12 (12A, 12B). Then, the image light V is enlarged by the lens 12 and is emitted to the observer side (−Y side).

  The image light V is slightly diffused in the left-right direction and the vertical direction by the optical sheet 20. Therefore, even if the image is magnified by the lens 12, the image visually recognized by the observer's eye E is, as shown in FIG. 3, compared to the display device 5 of the comparative example (FIG. 4B). Reference), the non-image area F2 caused by the non-pixel area G2 of the image source 11 can be suppressed as much as possible, and a clear image can be displayed.

  In addition, when the range is 20 ≦ θave × L / P ≦ 40, it is possible to observe a good image in which the pixels are not seen independently and the video is not excessively blurred. Further, an optimal image can be observed under more severe conditions, that is, within a range of 23 ≦ θave × L / P ≦ 35.

Next, the manufacturing method of the optical sheet 20 used for the display apparatus 1 of this embodiment is demonstrated.
As described above, the unit shapes 21a and the unit shapes 23a provided in the first optical layer 21 and the third optical layer 23 of the optical sheet 20 are formed in the same shape. Using a mold provided with a concave shape corresponding to the unit shape, a sheet-like member on which the unit shape is formed is formed by an extrusion molding method, an injection molding method, or the like.
Then, the sheet-like member on which the unit shape is formed is cut into a predetermined dimension, and the first optical layer 21 and the third optical layer 23 are obtained.
Thus, when the unit shape 21a and the unit shape 23a are formed in the same shape, the first optical layer 21 and the third optical layer 23 can be cut out simultaneously from one sheet-like member, and the optical sheet 20 Manufacturing efficiency can be improved.

Subsequently, a resin for forming the second optical layer 22 is filled on the surface of the first optical layer 21 on the unit shape 21a side, and the resin and the surface of the third optical layer 23 on the unit shape 23a side are pasted. In addition, the resin is cured in a state where a predetermined distance is provided between the first optical layer 21 and the third optical layer 23. At this time, the first optical layer 21 and the third optical layer 23 are arranged such that the extending direction of the unit shape 21a and the extending direction of the unit shape 23a intersect (orthogonal) each other.
Accordingly, the first optical layer 21, the second optical layer 22, and the third optical layer 23 are sequentially stacked. Furthermore, the optical sheet 20 is completed by providing the antireflection layer 24 on the surface of the first optical layer 21 (the surface opposite to the second optical layer 22 side).

  As described above, the display device 1 of the present embodiment has at least two or more optical layers between the video source 11 and the lens 12, and a plurality of unit shapes 21a and 23a are formed at the interface between the optical layers. Refractive index differences Δn1 and Δn2 of the adjacent optical layers provided with the optical sheet 20 and having unit shapes 21a and 23a formed at the interfaces are 0.005 ≦ Δn1 ≦ 0.1 and 0.005 ≦ Δn2 ≦ 0.1, respectively. And 20 ≦ θave × L / P ≦ 40 is satisfied, or 23 ≦ θave × L / P ≦ 35 is satisfied. Accordingly, the display device 1 can slightly diffuse the video light V emitted from the video source 11, displays a clear video to the observer, and causes non-pixel regions G <b> 2 of the video source 11. It is possible to suppress the video region F2 from being visually recognized by the observer.

Further, as described above, since the optical sheet 20 is positioned on the video source side (+ Y side) of the lens 12 in the display device 1 according to the present embodiment, the video source 11 is removed from the display device 1 (housing 30). Even in such a state, the lens 12 can be protected from foreign matter such as dust and dirt that has entered, and the lens 12 is not damaged or soiled by the foreign matter. Even when it becomes dirty or cloudy, it can be wiped off without damaging the unit shape.
In addition, the display device 1 of the present embodiment includes the reflection suppression layer 24 on the image source side (incident side, + Y side) surface of the optical sheet 20, and the reflection suppression layer 12 a on the image source side surface of the lens 12. Since it is provided, stray light can be suppressed and the brightness and contrast of the image can be improved.

  In the display device 1 of the present embodiment, the unit shape 21a is convex, and the Z direction (first direction) in the sheet surface (XZ surface) orthogonal to the thickness direction (Y direction) of the optical sheet 20 is used. ) And arranged in the X direction (second direction) orthogonal to the Z direction in the sheet plane, and the cross-sectional shape in the cross section (XY plane) parallel to the thickness direction and the arrangement direction of the optical sheet 20 is substantially circular. It is formed in an arc shape. Similarly, the unit shape 23a is convex, extends in the X direction in the sheet surface (XZ surface) orthogonal to the thickness direction (Y direction) of the optical sheet 20, and is orthogonal to the X direction in the sheet surface. The cross-sectional shape in the cross section (YZ plane) arranged in the Z direction and parallel to the thickness direction and the arrangement direction of the optical sheet 20 is formed in an arc shape. Thereby, the display device 1 can efficiently and evenly diffuse the image light passing through the unit shapes 21a and 23a.

  Further, in the display device 1 of the present embodiment, the optical sheet 20 has three or more optical layers, and the unit shape 21a and the unit shape 23a provided at each interface between adjacent optical layers in the sheet surface. The extending direction (Z direction, X direction) is orthogonal (intersect) when viewed from the thickness direction of the optical sheet 20. Thereby, the display apparatus 1 can diffuse the image light emitted from the image source 11 in a plurality of directions (left and right directions and vertical directions), and more non-image areas caused by the non-pixel areas of the image source 11 can be obtained. It can be effectively inconspicuous.

The cross sections of the unit shapes 21 a and 23 a in the arrangement direction of the unit shapes 21 a of the first optical layer 21 and the unit shapes 23 a of the third optical layer 23, and in the cross sections along the arrangement directions and the thickness direction of the optical sheet 20. The shape is not limited to the above example, and may be changed as appropriate.
Below, the other form of the optical sheet 20 used for the display apparatus 1 of this embodiment is demonstrated.

  For example, in the optical sheet 20, the extending direction of the unit shape 21a is the vertical direction (Z direction), the extending direction of the unit shape 23a is the left-right direction (X direction), and an example in which these are orthogonal to each other has been described. The extending direction of the unit shape 21a of the optical sheet 20 is a direction inclined by 45 ° with respect to the horizontal direction (inclined by 45 ° with respect to the vertical direction), and the extending direction of the unit shape 23a is with respect to the horizontal direction. The extending direction of the unit shape 21a and the extending direction of the unit shape 23a may intersect (in this case, orthogonal) when viewed from the Y direction.

The angle at which the extending direction of the unit shape 21a of the optical sheet 20 is inclined with respect to the vertical direction (Z direction) and the angle at which the extending direction of the unit shape 23a is inclined with respect to the left and right direction (X direction) are However, the angle is not limited to 45 °, and may be, for example, 15 ° or 30 °. The extending direction of each unit shape is appropriately set according to the pixel arrangement of the video source 11 or the desired optical performance. Good. Thereby, the effect of making the non-video region F2 caused by the non-pixel region G2 inconspicuous can be further enhanced.
Further, the extending direction of one unit shape may intersect with the extending direction of the other unit shape at an angle other than orthogonal. Even in such a form, it is possible to further enhance the effect of making the non-video region F2 caused by the non-pixel region G2 inconspicuous.

8 and 9 are diagrams illustrating details of another form of the optical sheet 20 used in the display device 1 of the present embodiment.
Fig.8 (a) is a perspective view of the optical sheet 20 of another form. FIG. 8B is a bb cross-sectional view of FIG. FIG.8 (c) is cc sectional drawing of Fig.8 (a). FIG. 9A is a diagram showing details of a part of FIG. 8B, and FIG. 9B is a diagram showing details of part b of FIG. 8C.
Regarding other forms of the optical sheet 20 shown below including the optical sheets 20 of other forms shown in FIG. 8 and FIG. A duplicate description is omitted. Further, for the sake of facilitating understanding, the drawings showing other forms of the optical sheet 20 shown below including FIGS. 8 and 9 show a form without the antireflection layer 24. The reflection suppression layer 24 as described above may be provided on the image source side (back side, + Y side) of the optical layer 21.
The x direction, y direction, and z direction shown in FIGS. 8 and 9 are orthogonal to each other, and the y direction is parallel to the Y direction. The x direction is 45 ° with respect to the X direction, and the z direction is 45 ° with respect to the Z direction.

In the optical sheet 20 shown in FIGS. 8 and 9, the unit shape 21a formed on the surface on the viewer side (−y side, −Y side) of the first optical layer 21 is shown in FIGS. 8 (a) and 8 (b). As shown in FIG. 3, the first optical layer 21 extends along the x direction inclined by 45 ° with respect to the left-right direction (X direction) and extends along the viewer side of the first optical layer 21 with respect to the vertical direction (Z direction). Are arranged in the z direction inclined by 45 °. As shown in FIGS. 8A and 8C, the unit shape 23a formed on the image source side (+ y side, + Y side) surface of the third optical layer 23 is the image source side of the third optical layer 23. Are extended in the z direction inclined by 45 ° with respect to the vertical direction (Z direction), and are arranged in a plurality of x directions inclined by 45 ° with respect to the left and right direction (X direction).
The extension direction (x direction) of the unit shapes 21a and the extension direction (z direction) of the unit shapes 23a intersect (orthogonal), and the arrangement direction (z direction) of the unit shapes 21a and the arrangement of the unit shapes 23a The direction (x direction) intersects (perpendicular).

In addition, the unit shape 21a is formed in a so-called prism shape in which a cross-sectional shape on a plane (yz plane) parallel to the z direction and the y direction is substantially triangular. Similarly, the unit shape 23a is formed in a so-called prism shape in cross section in a plane parallel to the x direction and the y direction (xy plane).
Here, the substantially triangular shape is not only a triangular shape including an isosceles triangle and an equilateral triangle, but also a shape in which the top of the triangular shape is chamfered to a curved surface or a plane, or a triangular slope is slightly curved. It also includes the shape.

8 and 9, each of the unit shapes 21a and 23a is parallel to the thickness direction of the optical sheet 20, and the cross-sectional shape in the cross section parallel to the arrangement direction is an isosceles triangle. ing. Further, the unit shapes 21a and 23a are formed in a state in which their isosceles triangles are continuous in each arrangement direction.
As shown in FIG. 9A, the arrangement pitch of the unit shapes 21a in the z direction is P1, the apex angle of the unit shapes 21a is θ1, and as shown in FIG. 9B, the unit shapes 23a in the x direction. The arrangement pitch is P2, and the apex angle of the unit shape 23a is θ2. The arrangement pitches P1 and P2 and the apex angles θ1 and θ2 are, for example, P1 = P2 = 0.2 mm and θ1 = θ2 = 175 °.

  In the optical sheet 20 shown in FIGS. 8 and 9, it is desirable that the arrangement pitches P1 and P2 of the unit shapes 21a and 23a satisfy 0.1 mm ≦ P1 ≦ 0.5 mm and 0.1 mm ≦ P2 ≦ 0.5 mm, respectively. . If the arrangement pitches P1 and P2 are less than 0.1 mm, it is difficult to manufacture the unit shapes 21a and 23a having such dimensions, and a light diffraction phenomenon is likely to occur. This is not preferable because the image becomes unclear. Moreover, when arrangement pitch P1, P2 is larger than 0.5 mm, the line between adjacent unit shapes may be visually recognized, and it is not preferable.

For human eyes, a line extending in the left-right direction (X direction) tends to be more visible than a direction inclined with respect to the left-right direction, a line extending in the vertical direction (Z direction), or the like. .
Therefore, as described above, by tilting the extending direction of each unit shape with respect to the left-right direction, the display device 1 of the present embodiment can visually recognize the line caused by the unit shape to the observer. It is possible to make it difficult for the observer to visually recognize the displayed image.

The optical sheet 20 shown in FIGS. 8 and 9 has a refractive index difference Δn1 between the first optical layer 21 and the second optical layer 22, and a refractive index difference Δn2 between the second optical layer 22 and the third refractive index layer. The range is preferably the same as in the above-described embodiment.
Further, the optical sheet 20 shown in FIGS. 8 and 9 needs to satisfy 20 ≦ θave × L / P ≦ 40, and more preferably satisfies 23 ≦ θave × L / P ≦ 35.

FIG. 10 is a diagram illustrating the relationship between the luminance and the diffusion angle of the optical sheet 20 according to another embodiment illustrated in FIGS. 8 and 9.
The relationship between the brightness and the diffusion angle of the optical sheet 20 shown in FIGS. 8 and 9 has two peaks corresponding to the unit-shaped slope formed in a substantially triangular shape, as shown in FIG. Or a waveform having a wide peak width as shown in FIG. In these cases, similarly to the case of FIG. 5, the light diffused in the range of −φ to + φ shown in FIG. 10 is a component that reaches the observer.

  As for the light diffused in the range of −φ to + φ, 20 ≦ θave × L / P ≦ 40 is satisfied or 23 ≦ θave × L / P ≦ 35 is satisfied as in the previous example. is necessary.

If the refractive index difference Δn1 between the first optical layer 21 and the second optical layer 22 and the refractive index difference Δn2 between the second optical layer 22 and the third optical layer 23 are larger than 0.1, It is not desirable because it is necessary to form each unit shape in a flat shape so as to satisfy the above formulas (1) and (2), and it becomes difficult to manufacture an optical sheet having such a unit shape. .
In addition, in the optical sheet 20 of the other form shown in FIGS. 8 and 9, it is refracted from the viewpoint of facilitating manufacture and refracting light to a degree sufficient to make the non-image area F2 inconspicuous. The rate differences Δn1 and Δn2 are more preferably 0.05.

  In the above description and FIGS. 8 and 9, the unit shapes 21 a and 23 a are parallel to the thickness direction of the optical sheet 20, and the cross-sectional shape in a cross section parallel to the arrangement direction of the unit shapes is an isosceles triangle shape. However, the present invention is not limited to this, and the unit shapes 21a and 23a may have the following forms.

FIG. 11 is a diagram showing another form of the unit shape 21 a provided in the optical sheet 20 shown in FIGS. 8 and 9. Each diagram in FIG. 11 corresponds to FIG. 9A. 11 illustrates another form of the unit shape 21 a of the first optical layer 21, the same applies to the unit shape 23 a of the third optical layer 23.
For example, as shown in FIG. 11A, a triangular top in the same cross section may be formed by a curved surface S1, or as shown in FIG. 11B, the triangular top is a flat surface S2. It is good also as a form formed by.
Further, as shown in FIG. 11C, a triangular slope in the same cross section may be formed by curved surfaces S3 and S4 that are slightly curved instead of a flat surface.
The optical sheet in which each unit shape is in the form as described above can achieve the same effects as the optical sheet shown in FIG.

FIG. 12 is a view for explaining another form of the optical sheet 20 shown in FIGS. 8 and 9. 12A is a cross-sectional view in a cross section (XY cross section) parallel to the thickness direction (Y direction) and parallel to the left-right direction (X direction), and FIG. Is a cross-sectional view in a cross section (YZ cross section) parallel to the vertical direction (Z direction).
8 and 9, the unit shapes 21a and 23a are substantially triangular (prism shape) in cross section, and the unit shape 21a is in the x direction inclined by 45 ° with respect to the left-right direction (X direction). A plurality of unit shapes 23a are arranged in the z direction inclined 45 ° with respect to the vertical direction (Z direction), and the unit shape 23a extends in the z direction inclined 45 ° with respect to the vertical direction (Z direction). Although a plurality of optical sheets arranged in the x direction inclined by 45 ° with respect to the left and right direction (X direction) are shown, the present invention is not limited to this.

For example, in the optical sheet 20 shown in FIGS. 8 and 9, the unit shape 21a extends in the vertical direction (X direction) as shown in FIG. 12A, and a plurality of unit shapes 21a are arranged in the left-right direction (X direction). As shown in FIG. 12B, the unit shape 23a may extend in the left-right direction (X direction) and be arranged in a plurality in the vertical direction (Z direction).
In the optical sheet 20 shown in FIG. 12, the refractive index difference Δn1 between the first optical layer 21 and the second optical layer 22, and the refractive index difference Δn2 between the second optical layer 22 and the third optical layer 23 are as described above. It is preferable that it is the same range as a form.
Even if the optical sheet 20 is in such a form, the image source 11 is satisfied by satisfying 20 ≦ θave × L / P ≦ 40 or satisfying 23 ≦ θave × L / P ≦ 35 as in the above-described embodiment. As shown in FIG. 3, the image light emitted from the light source is suppressed from being visually recognized by the observer due to the diffused image light, as shown in FIG. be able to.

FIG. 13 is a diagram illustrating another form of the optical sheet 20 shown in FIGS. 8 and 9. 13A is a cross-sectional view in a cross section (XY cross section) parallel to the thickness direction (Y direction) and parallel to the left-right direction (X direction). FIG. 13B is a cross section in the thickness direction (Y direction). Is a cross-sectional view in a cross section (YZ cross section) parallel to the vertical direction (Z direction). FIG. 13C is a perspective view of the first optical layer 21 as viewed from the surface on the viewer side (−Y side).
As shown in FIG. 13, the optical sheet 20 is configured by two layers of a first optical layer 21 and a second optical layer 22, and is on the viewer side (−Y side) surface of the first optical layer 21. The substantially quadrangular pyramid shaped unit shapes 21a may be arranged without a plurality of gaps in the vertical direction and the left-right direction. Here, the substantially quadrangular pyramid shape is not only a complete quadrangular pyramid shape, but also a shape in which the top of the quadrangular pyramid is chamfered to a curved surface or a plane, or a shape in which each triangular slope of the quadrangular pyramid is slightly curved Etc. are also included. In addition, the substantially quadrangular pyramid-shaped unit shapes 21a shown in FIG. 13 may be arranged in a direction inclined (for example, inclined by 45 °) with respect to the vertical direction (Z direction) and the horizontal direction (X direction). .

  Even if the optical sheet 20 has the form shown in FIG. 13, the image light emitted from the image source 11 is slightly reduced by satisfying 20 ≦ θave × L / P ≦ 40 or satisfying 23 ≦ θave × L / P ≦ 35. As shown in FIG. 3, it is possible to suppress the non-image area F2 caused by the non-pixel area G2 from being visually recognized by the observer due to the diffused image light. Further, the layer configuration can be reduced as compared with the optical sheet 20 shown in FIG. 2 and the optical sheet 20 shown in FIGS. 8 and 9, and the optical sheet 20 can be made thinner and lighter. It becomes. Furthermore, it becomes possible to manufacture the optical sheet 20 more easily and inexpensively.

FIG. 14 is a diagram illustrating another form of the optical sheet 20 used in the display device 1 of the present embodiment. FIG. 14A is a cross-sectional view in a cross section parallel to the horizontal plane (XY plane) of the optical sheet 20, and FIG. 14B is a cross-sectional view of part b in FIG. 14A. FIG. 14C is a diagram showing details of the portion c in FIG. 14A, and FIG. 14D is a diagram showing details of the portion d in FIG. 14B.
The optical sheet 20 shown in FIG. 14 has a plurality of convex unit shapes 21 a formed at the interface between the first optical layer 21 and the second optical layer 22, and is convex at the interface between the second optical layer 22 and the third optical layer 23. A plurality of unit shapes 23a are formed.

On the viewer side (−Y side) surface of the first optical layer 21, as shown in FIG. 14A, unit shapes 21a and flat portions 21b are alternately provided. The unit shapes 21a and flat portions 21b extend in the vertical direction (Z direction) and are arranged in the left-right direction (X direction) so as to be along the surface of the first optical layer 21 on the viewer side. .
Further, on the image source side (+ Y side) surface of the third optical layer 23, as shown in FIG. 14B, a plurality of unit shapes 23a and flat portions 23b are alternately formed. The unit shapes 23a and flat portions 23b extend in the left-right direction (X direction) and are arranged in the vertical direction (Z direction) along the surface of the third optical layer 23 on the image source side. .
The unit shape 23a and the flat portion 23b provided in the third optical layer 23 are extended in the extending direction (X direction) of the unit shape 21a and the flat portion 21b provided in the first optical layer 21 described above. (Z direction) and intersect (orthogonal).

In the optical sheet 20 of another form shown in FIG. 14, the unit shape 21 a is convex from the viewer side surface (the −Y side surface) of the first optical layer 21, as shown in FIG. It is formed so that the cross-sectional shape in the XY cross-section becomes a substantially arc shape. 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.
In the optical sheet 20 shown in FIG. 14, the unit shape 21a is formed in an arc shape, the radius of curvature is R1, and the width dimension in the left-right direction (X direction) is W1. The arrangement pitch in the left-right direction of the unit shapes 21a (flat portions 21b) is P1.

Similarly, as shown in FIG. 14D, the unit shape 23a is convex from the image source side surface (+ Y side surface) of the third optical layer 23, and the cross-sectional shape in the YZ cross section is formed in a substantially arc shape. Has been. In the optical sheet 20 shown in FIG. 14, the unit shape 23a is formed in an arc shape, the radius of curvature is R2, and the width dimension in the vertical direction (Z direction) is W2. The arrangement pitch in the vertical direction of the unit shapes 23a (flat portions 23b) is P2.
Furthermore, each unit shape and each flat portion provided in the first optical layer 21 and the third optical layer 23 are formed to have the same dimensions, for example, W1 = W2 = 0.1 mm, P1 = P2 = 0.24 mm and R1 = R2 = 0.5 mm.

In the optical sheet 20 shown in FIG. 14, the arrangement pitch P1 of the unit shapes 21a and the arrangement pitch P2 of the unit shapes 23a preferably satisfy 0.1 mm ≦ P1 ≦ 0.5 mm and 0.1 mm ≦ P2 ≦ 0.5 mm. .
If the arrangement pitches P1 and P2 are less than 0.1 mm, the arrangement interval of the unit shapes becomes too fine, and the influence of the diffracted light becomes large and the image becomes unclear. In addition, it is difficult to manufacture unit shapes.
Further, if P1 and P2 are larger than 0.5 mm, the arrangement interval of the unit shapes 21a and 23a becomes too coarse, which is not desirable because the non-image area F2 is easily visible to the observer.
In the optical sheet 20 shown in FIG. 14, the refractive index difference Δn1 between the first optical layer 21 and the second optical layer 22, and the refractive index difference Δn2 between the second optical layer 22 and the third optical layer 23 are as described above. It is preferable that it is the same range as embodiment.
Further, the optical sheet 20 shown in FIG. 14 needs to satisfy 20 ≦ θave × L / P ≦ 40, and more preferably satisfies 23 ≦ θave × L / P ≦ 35.

The optical sheet 20 shown in FIG. 14 is emitted from the image source 11, and out of the light incident from the image source side surface of the optical sheet 20, the light transmitted through the flat portion 21b and the flat portion 23b is directly emitted to the observer side. In addition, the light incident on the unit shape 21a can be diffused in the left-right direction, and the light incident on the unit shape 23a can be diffused in the vertical direction and emitted to the lens 12 side.
As a result, the display device 1 displays a clear image to the observer and suppresses the non-image region F2 caused by the non-pixel region G2 of the image source 11 from being noticeable due to the minute diffusion of the image light. can do. In particular, since the light transmitted through the flat portion 21b and the flat portion 23b is hardly diffused, the image light reaching the observer can be displayed more clearly by adopting such a form.

  In other words, the display device 1 can slightly diffuse the image light emitted from the image source 11 in the vertical direction and the left-right direction, displays a clear image with less blur to the observer, and non-pixels of the image source 11. It is possible to suppress the non-video region F2 caused by the region G2 from being visually recognized by the observer. In addition, a specific diffusion angle range can be appropriately defined in accordance with the specifications of the display device 1 (pixel arrangement pitch d and distance between the eye E of the observer and the display surface 11a). It is possible to realize display of a well-defined video and suppression of visual recognition of the non-video area F2.

FIGS. 15, 16, and 17 are diagrams illustrating another form of the optical sheet 20 shown in FIG. FIGS. 15 (a), 16 (a), and 17 (a) correspond to FIG. 14 (a), respectively, and FIGS. 15 (b), 16 (b), and 17 (b). ) Are diagrams corresponding to FIG. 14B, respectively.
In the optical sheet 20 of another form shown in FIG. 14, the unit shape 21a is convex from the surface on the observer side (−Y side) of the first optical layer 21, as shown in FIG. The cross-sectional shape may be triangular, the unit shape 23a may be convex from the image source side (+ Y side) surface of the third optical layer 23, and the cross-sectional shape in the YZ cross section may be triangular.

Further, the unit shapes 21a and 23a may be concave instead of convex.
For example, as shown in FIG. 16, the unit shape 21a is a concave shape that is recessed from the surface on the observer side (−Y side) of the first optical layer 21, and the cross-sectional shape in the XY cross section is formed in an arc shape. Alternatively, the two convex surfaces may be opposed to each other in the left-right direction.
Similarly, the unit shape 23a is a concave shape recessed from the image source side (+ Y side) surface of the third optical layer 23, and the cross-sectional shape in the XY section is two convex surfaces formed in an arc shape in the vertical direction. It is good also as a form which mutually opposes.

Further, as shown in FIG. 17, the unit shape 21 a is a concave shape recessed from the viewer side surface (the surface on the −Y side) of the first optical layer 21 in which the cross-sectional shape in the XY cross section is triangular. The cross-sectional shape in the YZ cross section may be a triangular shape, and may include a unit shape 23a that is a concave shape recessed from the image source side surface (+ Y side surface) of the third optical layer 23.
Even in the convex or concave form as described above, the display device 1 is not diffusing the light transmitted through the flat part 21b and the flat part 23b out of the light emitted from the video source 11 on the viewer side. In addition to being emitted, the light incident on the unit shape 21a can be slightly diffused in the left-right direction, and the light incident on the unit shape 23a can be slightly diffused in the vertical direction and emitted to the viewer side.

The optical sheet 20 shown in FIGS. 15, 16, and 17 also needs to satisfy 20 ≦ θave × L / P ≦ 40, and more preferably satisfies 23 ≦ θave × L / P ≦ 35. Good.
As a result, the display device 1 displays a clear image with less blur to the observer, and the non-image region F2 caused by the non-pixel region G2 of the image source 11 is conspicuously observed by minute diffusion of the image light. This can be suppressed.

FIG. 18 is a diagram for explaining another form of the head-mounted display device 1 of the present embodiment.
As shown in FIG. 18, the optical sheet 20 may be disposed closer to the observer side (−Y side) than the lens 12. Even if such an arrangement is adopted, the display device 1 displays a clear image with less blur to the observer and a non-image region caused by the non-pixel region G2 of the image source 11 due to a slight diffusion of the image light. It can suppress that F2 is observed conspicuously.
As shown in FIG. 18, even when the optical sheet 20 is arranged closer to the observer side (−Y side) than the lens 12, it is necessary to satisfy 20 ≦ θave × L / P ≦ 40. More preferably, 23 ≦ θave × L / P ≦ 35 may be satisfied.

(Deformation)
The present invention is not limited to the above-described embodiments and the like, and various modifications and changes are possible, and these are also within the scope of the present invention.

(1) In the embodiment, the optical sheet 20 has an example in which the three optical layers of the first optical layer 21, the second optical layer 22, and the third optical layer 23 are sequentially stacked. It is not limited to this.
For example, the optical sheet 20 may have a configuration in which two layers of the first optical layer 21 and the second optical layer 22 are laminated according to desired optical performance and the like, and a configuration including four or more optical layers. It is good.

(2) In the embodiment, the example in which the unit shapes 21a and 23a are formed at the interface between adjacent optical layers of the optical sheet 20 is shown, but the present invention is not limited to this.
FIG. 19 is a diagram for explaining a modified optical sheet 120.
For example, as shown in FIG. 19, the optical sheet 120 has a two-layer structure of a first optical layer 121 and a second optical layer 122, and a fine unit shape is randomly formed between the first optical layer 121 and the second optical layer 122. It is good also as a form which is provided and an interface becomes rough surface and forms unit shape 121a.
Even in such a configuration, if 20 ≦ θave × L / P ≦ 40 is satisfied or 23 ≦ θave × L / P ≦ 35 is satisfied, the image light emitted from the image source 11 is slightly reduced by the optical sheet 120. In the display device 1, the non-video area F2 caused by the non-pixel area G2 of the video source 11 can be made inconspicuous. In this case, the layer configuration can be reduced as compared with the optical sheet 20 shown in FIG. 2 or the like used in the display device 1 of the above-described embodiment, and the optical sheet can be made thinner or lighter. It becomes possible.

(3) In the embodiment, the optical sheet 20 has been shown to be held by the holding unit 32, but is not limited to this. It is good also as a form etc. which are joined so that the opening part 311 may be block | closed, and it is good also as a form stuck so that the opening part 331 may be blocked | closed to the image source side of the opening part 331 of the holding | maintenance part 33 holding the lens 12. FIG.

(4) In the embodiment, the optical sheet 20 shows an example in which the first optical layer 21 is arranged on the image source side (+ Y side) and the third optical layer 23 is arranged on the observer side (−Y side). However, the present invention is not limited to this, and the first optical layer 21 may be disposed on the viewer side and the third optical layer 23 may be disposed on the image source side.

(5) In the embodiment, the optical sheet 20 has been described as an example in which the refractive index of the first optical layer 21 and the third optical layer 23 is higher than the refractive index of the second optical layer 22, but is not limited thereto. For example, the refractive index of the first optical layer 21 and the third optical layer 23 may be lower than the refractive index of the second optical layer 22.

(6) In the embodiment, the example in which the second optical layer 22 is a layer made of an ultraviolet curable resin has been shown. However, the present invention is not limited to this. For example, the second optical layer 22 is made of a permeable adhesive. In addition, the first optical layer 21 and the third optical layer 23 may be bonded. In this case, the refractive index of the pressure-sensitive adhesive constituting the second optical layer 22 has a refractive index difference of 0.005 or more and 0.1 or less with respect to the refractive indexes of the first optical layer 21 and the third optical layer 23. Must be set in range.

(7) In the embodiment, the video source 11 may be fixed in advance to the display device 1 and not attachable / detachable.

  In addition, although embodiment and a deformation | transformation form can also be used in combination as appropriate, detailed description is abbreviate | omitted. Further, the present invention is not limited by the above-described embodiments and the like.

1 Display device 5 Display device (conventional)
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 Antireflection layer 20 Optical sheet 20A Optical sheet 20B Optical sheet 21 First 1 optical layer 21a unit shape 21b flat part 22 second optical layer 23 third optical layer 23a unit shape 23b flat part 24 antireflection layer 30 housing 31 holding part 32 holding part 33 holding part 51 image source (conventional)
52 Lens (Conventional)
120 optical sheet 121 first optical layer 121a unit shape 122 second optical layer 311 opening 321 opening 331 opening

Claims (6)

A video source in which a plurality of pixel regions are arranged to emit video light;
A lens that magnifies and emits the image light to the viewer side;
An optical sheet disposed between the image source and the lens or on the viewer side of the lens;
With
In the optical sheet, two or more optical layers are laminated, and a plurality of convex or concave unit shapes are formed at an interface between the adjacent optical layers,
When the luminance at the diffusion angle θ is I (θ), the distance between the lens and the optical sheet is K, and the effective radius of the lens is R, the average diffusion angle θave of the optical sheet is

When the distance between the optical sheet and the display layer of the video source is defined as L, and the pixel arrangement pitch where the pixel regions are arranged is defined as P,
20 ≦ θave × L / P ≦ 40
A display device that meets the requirements. The display device according to claim 1,
23 ≦ θave × L / P ≦ 35
A display device that meets the requirements. The display device according to claim 1 or 2,
The unit shape is convex and extends in a first direction in the sheet surface orthogonal to the thickness direction of the optical sheet, and in a second direction orthogonal to the first direction in the sheet surface. The cross-sectional shape in a cross section parallel to the thickness direction of the optical sheet and parallel to the second direction is formed in a substantially arc shape,
A display device. In the display device according to any one of claims 1 to 3,
The unit shapes extend in a first direction in a sheet surface orthogonal to the thickness direction of the optical sheet, and are arranged in a second direction orthogonal to the first direction in the sheet surface, The cross-sectional shape in a cross section parallel to the thickness direction of the sheet and parallel to the second direction is formed in a substantially triangular shape,
A display device. In the display device according to any one of claims 1 to 4,
The unit shape is convex and is formed in a substantially quadrangular pyramid shape arranged along a sheet surface orthogonal to the thickness direction of the optical sheet,
A display device. In the display device according to any one of claims 1 to 5,
The optical sheet has three or more optical layers, and the extending direction in the sheet surface direction of the unit shape provided at each interface between the adjacent optical layers is from the thickness direction of the optical sheet. Seeing and crossing,
A display device.

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