WO2019044501A1

WO2019044501A1 - Head-mounted display

Info

Publication number: WO2019044501A1
Application number: PCT/JP2018/030314
Authority: WO
Inventors: 朋一梅澤; 隆薬師寺
Original assignee: 富士フイルム株式会社
Priority date: 2017-09-04
Filing date: 2018-08-14
Publication date: 2019-03-07
Also published as: JPWO2019044501A1

Abstract

Provided is a head-mounted display in which sharp image display is realized while visibility of a black matrix is reduced. The head-mounted display according to the present invention is provided with a display panel, an enlarging optical system for enlarging an image displayed in the display panel, and a microlens array disposed in an optical path between the display panel and the enlarging optical system. In the microlens array, a plurality of concave lenses are arranged, and concave surfaces of the concave lenses are disposed facing toward the enlarging optical system.

Description

Head mounted display

The present invention relates to a head mounted display.

The head mounted display is a display that displays an image at a close distance to the eye of the user. As the head mounted display, there are a goggle type as disclosed in Patent Document 1, a glasses type as disclosed in Patent Document 2, and the like. In any case, in the head mounted display, an optical lens with high curvature is employed to display an image with a wide viewing angle in front of the user's eye.

As described above, in a head mounted display using an optical lens with a high curvature to display an image with a wide viewing angle in front of the eyes, the pixels of the display panel appear to be enlarged, so the black matrix (pixel grid) between the pixels is noticeable As a result, there is a problem that pixels are visually recognized as a line of dots and the image quality is degraded.

As a method of suppressing the deterioration of the image quality, Patent Document 3 proposes that an optical element such as a microlens array is provided between the display panel and the eyepiece to act as an optical low pass filter.

JP 2011-145607 A Japanese Patent Laid-Open No. 11-346336 JP, 2016-139112, A

FIG. 8 is a view showing an internal configuration of the head mounted display of Patent Document 3, and is provided with a microlens array 230 in an optical path from the display panel 200 to the eyepiece lens 210. Patent Document 3 discloses that the low-pass filter effect of the microlens array 230, that is, the effect of diffusing light blurs the image, so that the black matrix of the display panel can be made inconspicuous.

As shown in FIG. 9, in the display panel 200, a red pixel 212R, a green pixel 212G, and a blue pixel 212B (referred to collectively as “pixel 212” when these are collectively referred to) are arranged. There is a black matrix 214. When a general convex microlens array 230 as shown in FIG. 8 is arranged such that the convex surface is on the eyepiece side, in order to obtain the diffusion effect, as shown in FIG. It is necessary to use a light beam which spreads once it is made to converge. However, such rays are likely to be diffused to adjacent pixels and even diffused beyond the adjacent pixels. Specifically, the light ray 240 which is incident on the microlens array 230 from the red pixel 212R and is output and refracted from the convex surface 232 thereof travels to the adjacent green pixel 212G side. In addition, the green pixel 212G enters the microlens array 230, and the light ray 242 output and refracted from the convex surface 232 travels to the adjacent red pixel 212R side. In this manner, the light output from each pixel 212 is largely refracted by the convex surface 232 and travels beyond the black matrix 214 and leaks to the adjacent pixel side, so that the effect of making the black matrix inconspicuous can be obtained. There is a problem that the sharpness of the image is reduced and the entire image is blurred.

An object of the present invention is to provide a head mounted display which realizes sharp image display while reducing the visibility of the black matrix.

The head mounted display of the present invention comprises a display panel;
Magnifying optical system that magnifies the image displayed on the display panel,
And a microlens array disposed in the optical path between the display panel and the magnifying optical system;
A plurality of microlens arrays are arranged such that a plurality of concave lenses are arranged, and the concave surface of the concave lens is directed to the magnifying optical system.

Preferably, in the head mounted display of the present invention, the microlens array is disposed in contact with the image display surface of the display panel.

It is preferable that the head mounted display of the present invention has an anti-reflection function on the concave surface.

The anti-reflection function can be realized by a moth-eye structure or a dielectric multilayer film provided on a concave surface.

The head mount display of the present invention comprises a microlens array in the optical path between the display panel and the magnifying optical system for magnifying the image displayed on the display panel, and the microlens array is arranged with a plurality of concave lenses. And the concave surface of the concave lens is directed to the magnifying optical system. According to such a configuration, the visibility of the black matrix can be reduced and sharp image display can be realized.

It is the figure which looked at the structure of the head mounted display of 1st Embodiment from upper direction. It is a figure for demonstrating the internal structure of the head mounted display of FIG. It is a figure for demonstrating the effect by a concave micro lens array. It is a sectional view of a concave micro lens array. It is a sectional view of a concave micro lens array. It is a perspective view which shows schematic structure of the head mounted display of 2nd Embodiment. It is a figure for demonstrating the internal structure of the head mounted display of FIG. It is a figure for demonstrating the internal structure of the head mounted display of a prior art. It is a figure for demonstrating the light diffusion by the micro lens array which consists of convex lenses.

Hereinafter, embodiments of the head mounted display of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration view of the head mount display (HMD) 1 of the first embodiment as viewed from above. FIG. 1 shows the goggle-like main body 2 and its internal configuration, but in addition, various contacts such as a front contact portion and a temporal contact portion (not shown) for enhancing the mountability to be worn by the wearer on the head. It has a department.

The HMD 1 includes a display panel 10 provided in front of the eye, an eyepiece lens 20 disposed at an assumed position of the left and right pupils, and a microlens array disposed in the light path from the display panel 10 to the eyepiece lens 20 (MLA: Micro Lens Allay) and 30 are provided. In the present embodiment, the eyepiece 20 constitutes a magnifying optical system that magnifies the image of the display panel 10. The MLA 30 is formed by arranging a plurality of concave lenses. In the following, it is referred to as a concave MLA 30. The concave MLA 30 is disposed such that the concave surface 32 of the concave lens is on the eyepiece 20 side.

FIG. 2 is a diagram for explaining an internal configuration of the HMD 1.
The display panel 10 is preferably a lightweight and high-definition display panel such as a liquid crystal panel or an organic EL panel. The concave MLA 30 is disposed such that the concave surface 32 is on the eyepiece 20 side, and the light from the display panel 10 passes through the concave MLA 30 and is emitted from the concave surface 32 to the eyepiece 20 side.

The concave MLA 30 may be provided in the light path between the display panel 10 and the magnifying optical system (here, the eyepiece lens 20), but from the viewpoint of suppressing color mixing with adjacent pixels, the concave MLA 30 is close to the display panel 10 or It is preferable to arrange | position in contact. Here, the image display surface of the display panel 10 is preferably disposed on the eyepiece 20 side of the display panel 10, and the concave MLA 30 is preferably disposed in contact with the image display surface of the display panel 10. In the configuration in which the concave MLA 30 is disposed in contact with the image display surface of the display panel 10, the concave MLA 30 may be attached to the image display surface via the adhesive layer, or the adhesive layer is not provided in a state of contact. It may be held. In addition, the concave MLA 30 may be incorporated into the display panel at the manufacturing stage of the display panel, and the display panel and the microlens array may be integrated.

The HMD 1 is configured to observe an image displayed on the display panel 10 through the eyepiece lens 20 and the concave MLA 30 of the user's eye 220. Although the display panel 10 of the HMD is compact, since it is magnified and observed by the eyepiece lens 20, it looks to the user as if there is a large display in front of the eyes. In the state where the concave MLA 30 is not provided, the black matrix between the pixels of the display panel 10 becomes noticeable by the magnifying action by the eyepiece lens 20, and the arrangement of dots is emphasized and visually recognized. However, the HMD 1 of the present embodiment includes the concave MLA 30, and the black matrix of the display panel 10 becomes inconspicuous due to the light diffusion effect of the concave MLA 30.

FIG. 3 is a figure for demonstrating the light-diffusion effect by concave MLA30.
As shown in FIG. 3, the display panel 10 is provided with a red pixel 12R, a green pixel 12G, and a blue pixel 12B. In the following, when the pixels are generically referred to without distinction of color, they are simply referred to as "pixels 12". A black matrix 14 exists between the pixels 12 of the display panel 10. As described above, in the state where the concave MLA 30 is not provided, when the line of the pixels 12 is observed by enlarging the eyepiece lens 20, the black matrix 14 is noticeable, so the pixels 12 are visually recognized as a line of dots.

On the other hand, when the concave MLA 30 is provided, the light beam 40 from each pixel 12 spreads by the action of the concave lens (see FIG. 3), and light between adjacent pixels is mixed between the boundaries of the pixels, and black matrix Blur and become unnoticeable. Further, since the bending in the diffusion direction is gentler than that of a convex lens, the color mixture with adjacent pixels can be reduced. Thereby, the sharpness of the image can be maintained. In addition, since the concave lens essentially has a light diffusing function, the function for reducing the black matrix between the pixels can be easily obtained. Therefore, if it is concave MLA, even if it is a curved surface with a small concave surface, the effect of reducing a black matrix can fully be acquired. When the curvature is small (that is, the curvature radius is large), the height of the unevenness of the lens surface, that is, the height difference between the concave and the convex becomes small. The concave MLA is manufactured by transferring the shape from the mold, but when the height of the concavo-convex is small, it is easy to transfer and the merit that the lens accuracy can be improved is obtained.
Further, in the case of diffusing a light beam using a convex lens, as described above, the light beam has to take an optical path which once diffused and then diffused, which tends to restrict the optical design. On the other hand, in the case of a concave lens, light is inherently diffused, so that limitation in optical design is less likely to occur. Therefore, concave MLA is more advantageous in design freedom than convex MLA when manufacturing MLA, and when designing an optical path in an HMD combined with other optical members.

Although FIG. 3 shows the concave MLA 30 in which the pitch of the pixels 12 and the pitch of the concave surface 32 are approximately 1: 1, the pitch of the concave surface 32 in the concave MLA 30 does not necessarily coincide with the pixel 12 pitch. It is also good. The pitch of the concave surfaces 32 may be smaller than the pixel pitch so that the plurality of concave surfaces 32 correspond to one pixel. The pitch, size, etc. of the concave surface may be appropriately determined in accordance with the pixel pitch.
The pitch and curvature of the concave surface may be appropriately set so that the effects of black matrix removal and color mixture suppression (realization of a sharp image) by the concave MLA 30 become optimal.

As for the shape of the concave surface of the concave lens in the concave MLA 30, the curvature radius of the concave lens is preferably 1.5 times or more of the lens pitch, more preferably 2 times or more, and 2.5 times or more. More preferable. For example, in the case of one pixel 60 μm × 60 μm (in the case of R / G / B pitch 20 μm), the lens pitch of the concave MLA is preferably about 20 μm, and the curvature radius of the concave surface of the concave lens is preferably 50 μm or more. Here, the R / G / B pitch is the pitch of the pixel 12 described above.

In addition, it is preferable that the concave surface 32 of the concave MLA 30 be provided with a reflection preventing function (reflection preventing layer). By providing the concave surface 32 with the anti-reflection function (antireflection layer), it is possible to suppress the reflection on the concave surface 32 of the light entering the concave MLA 30 from the display panel, and as a result, the multiple reflection in the concave MLA 30. The output light from a certain pixel may be emitted from an adjacent pixel or an area of a pixel separated from the adjacent pixel by repeating multiple reflection in the concave MLA 30, and color mixing may occur. That is, by suppressing multiple reflection, it is possible to effectively suppress the occurrence of color mixing, and it is possible to display a sharper image.

FIGS. 4 and 5 are cross-sectional views of a concave MLA 30 provided with a reflection preventing function (reflection preventing layer) on the concave surface 32. FIG.
In the concave MLA 30 shown in FIG. 4, a moth-eye structure 34 is formed on the concave surface 32. The moth-eye structure 34 is a fine uneven structure as shown in FIG. 4 and is a structure having an antireflection function. The moth-eye structure 34 may be formed by processing the concave surface 32 itself, or may be made of a separate material on the surface of the concave surface 32. By forming a thin film containing aluminum such as aluminum, alumina or aluminum nitride on the surface of the concave surface 32 and immersing it in warm water (for example, 80 ° C. or more), a fine uneven structure made of boehmite can be formed. The fine concavo-convex structure made of this boehmite can be provided on the concave surface 32 as the moth-eye structure 34. Alternatively, using the boehmite as an etching mask, the surface of the concave surface 32 is etched by performing reactive ion etching from the surface of the boehmite to form a fine concavo-convex structure corresponding to the fine concavo-convex structure of the boehmite. Can. As described above, by processing the concave surface 32 by fine asperity, it is possible to obtain a fine asperity structure having higher durability than boehmite.

In the concave MLA 30 shown in FIG. 5, the anti-reflection film 36 is formed on the concave surface 32. The antireflective film 36 can be composed of a low refractive index layer having a refractive index smaller than that of the concave MLA 30. The antireflection film 36 is formed by alternately laminating a plurality of low refractive index layers having a relatively low refractive index and high refractive index layers having a relatively high refractive index, each having a higher antireflection function. Preferably, a dielectric multilayer film is provided.

As described above, the configuration provided with the anti-reflection function provided on the concave surface 32 of the MLA 30 may be either a moth-eye structure or an anti-reflection film. The use of the method of producing boehmite as described above is preferable because it can be very simply configured to provide uniform antireflection performance.

The head mounted display of the present invention is not limited to the goggle type as shown in FIG. 1, but may be a glasses type. FIG. 6 is a perspective view showing the appearance of a head mounted display according to a second embodiment of the present invention. FIG. 7 is a view showing an internal configuration of the head mounted display shown in FIG.

The head mounted display 101 of the second embodiment shown in FIG. 6 is a glasses-type head mounted display. The HMD 101 of the present embodiment has the display image 140 superimposed on the image of the outside world on a part of the field of view on the eyeglasses provided with the eyeglass frame 102 and the eyelid 104 of eyeglasses connected to the eyeglass frame 102 Display unit 108 is incorporated. In the head mounted display 101 of the present embodiment, a control signal of a moving image or a still image taken out as the display image 140 is separately provided image information through an optical fiber 109 drawn to the outside from the rear end of the eyelid 104 of the glasses. It is supplied from the transmitting means.

As shown in FIG. 7, the display unit 108 includes a display panel 110, a refractive lens 120, and a flat half mirror 122.
The display panel 110 displays an image (original image) sent via the optical fiber 109. The refractive lens 120 has a function of enlarging the original image on the screen of the display panel 110 and throwing it to the eye 220 of the wearer. The refractive lens 120 constitutes a magnifying optical system. The flat plate half mirror 122 has a function of reflecting the image light from the refractive lens 120 toward the eye 220 and transmitting the light from the image of the external world in the middle of the optical path from the refractive lens 120 to the eye. .

A concave MLA 30 is provided between the display panel 110 of the display unit 108 and the refractive lens 120 which is a magnifying optical system.

The image of the outside world is displayed as if the virtual image (display image) 140 of the original image displayed on the display panel 110 enlarged by the dioptric lens 120 is part of the field of view from the glasses in the wearer's eye 220 It will be projected again. By providing the concave MLA 30, the visibility of the black matrix of the display panel 110 can be reduced, and the wearer can visually recognize a sharp image as the virtual image 140 with almost no visual recognition of the black matrix. The effects and advantages of the concave MLA 30 are the same as those of the HMD 1 of the first embodiment. The concave MLA 30 is the same as that of the first embodiment in that it is more preferable to use one having the concave surface 32 with the radiation preventing function, as shown and described in FIG. 4 or FIG. 5.

As described above, in any of the head mounted displays of the first and second embodiments, it is possible to realize sharp image display while reducing the visibility of the black matrix of the display panel.
In the head mounted display of the present invention, the configuration and arrangement of the display panel and the magnifying optical system are not limited to the configurations of the above embodiments. As an expansion optical system, for example, a configuration provided with a reflecting mirror such as a concave mirror may be used. In addition, although the magnifying optical system may be configured of one component, it may be configured by combining a plurality of optical components.

1,101 head mounted display 2 main body 7 refractive lens 10 display panel 12 pixel 12B blue pixel 12G green pixel 12R red pixel 14 black matrix 20 eyepiece lens 30 concave lens microlens array 32 concave 34 moth eye structure 36 antireflective film 40 light ray 102 Eyeglass frame 104 106 106 Eyeglass lens 108 Display unit 109 Optical fiber 110 Display panel 120 Refractive lens 122 Flat plate half mirror 140 Displayed image (virtual image)
Reference Signs List 200 display panel 210 eyepiece 212 pixel 212B blue pixel 212G green pixel 212R red pixel 214 black matrix 220 eye 230 convex lens micro lens array 232

convex surface

240, 242 rays

Claims

Display panel,
An enlargement optical system for enlarging an image displayed on the display panel;
A microlens array disposed in a light path between the display panel and the magnifying optical system;
A head mount display, wherein the microlens array is formed by arranging a plurality of concave lenses, and the concave surface of the concave lens is directed to the magnifying optical system.
The head mounted display according to claim 1, wherein the microlens array is disposed in contact with an image display surface of the display panel.
The head mounted display according to claim 1, wherein the concave surface is provided with an anti-reflection function.
The head mounted display according to claim 3, wherein a moth-eye structure is provided on the concave surface.
The head mounted display according to claim 3, wherein an antireflective film is provided on the concave surface.