Image display device

Abstract

To provide an image display device with which, when displaying an image having different field angles for the left and right eyes, it is possible to display a natural image in which the boundary between a single-eye region and a binocular region does not stand out.SOLUTION: An image display device (101) comprises: a first and a second display element (107, 106); a first and a second optical system (105, 104) for guiding a first and a second image display on the first and second display elements to the left and right eyes of a user, respectively; and adjustment means (120) for adjusting the luminance of each of the first and second images. The first image has a first and a second region, and the second image has a third and a fourth region, with the second and third regions being binocular regions, the first and fourth regions being single-eye regions. The adjustment means reduces the luminance of the first image in the rightward direction from the first position (P1) of the second region, reduces the luminance of the second image in the leftward direction from the second position (P2) of the third region, and changes at least one of the first and second positions in accordance with the brightness of at least one of the first and second images.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an image display device. [Background technology]

[0002] Conventionally, there are known image display devices such as head-mounted displays (HMDs) that can display images with a wide angle of view by displaying images with different angles of view (monocular regions) to the left and right eyes of a user and displaying a part of the angle of view (binocular regions) so that the two eyes overlap. In such image display devices, the boundary between the monocular region and the binocular region can be conspicuous in some cases.

[0003] Patent Document 1 discloses a technique for making the boundary between the monocular region and the binocular region less noticeable by reducing the brightness of the image toward the boundary in the binocular region using a neutral density filter or image processing. Patent Document 2 discloses a technique for varying the start position when reducing the brightness of the image toward the boundary in the binocular region using a neutral density filter or image processing. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-337299 [Patent Document 2] Japanese Patent Application Publication No. 2017-212720 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if the eyepiece optical system has a nose recess or a forehead recess to prevent the lens from hitting the user's nose or forehead, the effective optical diameter becomes narrower, reducing the amount of light. The technologies disclosed in Patent Documents 1 and 2 do not take into consideration the loss of light caused by the lens in the eyepiece optical system. As a result, the loss of image brightness is compounded by the loss of light caused by the lens, which can make the image darker than necessary and prevent natural viewing.

[0006] Therefore, an object of the present invention is to provide an image display device that can display natural images in which the boundary between the monocular area and the binocular area is not noticeable when displaying images with different angles of view to the left and right eyes. [Means for solving the problem]

[0007] An image display device according to one aspect of the present invention includes a first display element and a second display element, a first optical system and a second optical system that guide a first image displayed on the first display element and a second image displayed on the second display element to a first exit pupil and a second exit pupil corresponding to the left and right eyes of a user, respectively, and an adjustment unit that adjusts the brightness of each of the first image and the second image, wherein the first image has a first region and a second region in order from the left to the right of the user, and the second image has a third region and a fourth region in order from the left to the right of the user, The second area of ​​the first image and the third area of ​​the second image are binocular areas that can be observed with both eyes of the user, and the first area of ​​the first image and the fourth area of ​​the second image are monocular areas that can be observed with one eye of the user, and the adjustment means decreases the brightness of the first image from a first position in the second area of ​​the first image to the right, and decreases the brightness of the second image from a second position in the third area of ​​the second image to the left, and changes at least one of the first position and the second position depending on the brightness of at least one of the first image and the second image.

[0008] Other objects and features of the present invention will be described in the following embodiments. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an image display device that can display natural images in which the boundary between the monocular area and the binocular area is not noticeable when displaying images with different angles of view to the left and right eyes. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of an image display device according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram of an eyepiece optical system according to the first embodiment. [Figure 3] 1 is an external view of an image display device according to a first embodiment. [Figure 4] FIG. 2 is an explanatory diagram of how an image is viewed with both eyes in the first embodiment. [Figure 5] FIG. 3 is an explanatory diagram of a luminance gradient in the first embodiment. [Figure 6] FIG. 3 is an explanatory diagram of inverse gamma correction of a luminance gradient in the first embodiment. [Figure 7] FIG. 2 is an explanatory diagram of an eyepiece optical system according to the first embodiment. [Figure 8] FIG. 4 is an explanatory diagram of a reduction in the amount of light in an image due to the eyepiece optical system in the first embodiment. [Figure 9] FIG. 3 is an explanatory diagram of gradation processing in the first embodiment. [Figure 10] FIG. 10 is an explanatory diagram of an image display device according to a second embodiment. [Figure 11] FIG. 10 is an explanatory diagram of an eyepiece optical system according to a second embodiment. [Figure 12] FIG. 10 is an explanatory diagram of an eyepiece optical system according to a second embodiment. [Figure 13] FIG. 10 is an explanatory diagram of gradation processing in the second embodiment. [Figure 14] FIG. 10 is an explanatory diagram of gradation processing in the second embodiment. [Figure 15] FIG. 10 is an explanatory diagram of an image display device according to a third embodiment. [Figure 16] FIG. 10 is an explanatory diagram of an eyepiece optical system according to a third embodiment. [Figure 17] FIG. 10 is an explanatory diagram of an eyepiece optical system according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0012] (First embodiment) First, an image display device (image observation device) 101 according to a first embodiment of the present invention will be described with reference to Figs. 1 to 3. Fig. 1 is an explanatory diagram of the image display device 101. Fig. 2 is an explanatory diagram of the eyepiece optical system of the image display device 101. Fig. 3 is an external view of the image display device 101. In this embodiment, the image display device 101 is an HMD (Head Mounted Display), but is not limited to this.

[0013] In FIG. 1, reference numeral 102 denotes the right eye (second exit pupil) of a user (observer), and 103 denotes the left eye (first exit pupil) of the user. The image display device 101 has a lens 104 constituting an eyepiece optical system for the right eye (second optical system), and a lens 105 constituting an eyepiece optical system for the left eye (first optical system). The image display device 101 also has a display element (second display element) 106 that displays an image for the right eye, and a display element (first display element) 107 that displays an image for the left eye. In this embodiment, the display elements 106 and 107 are each an organic EL display, but the present invention is not limited to this.

[0014] Lens 104 enlarges an image (second image) displayed on display element 106 and guides it to the user's right eye (second exit pupil corresponding to the right eyeball) 102. Lens 105 enlarges an image (first image) displayed on display element 107 and guides it to the user's left eye (first exit pupil corresponding to the left eyeball) 103. The display angle of view of lens 104 is 35° to the right and 25° to the left, and the display angle of view of lens 105 is 25° to the right and 35° to the left, and the angles of view displayed by lenses 104 and 105 are different from each other. In addition, the vertical display angle of view is 60°. The distance (eye relief E1) from image display device 101 (the final surface of the ocular optical system (lens surfaces of lenses 104 and 105)) to the pupil of the user's eyeball (eyepoint) is 18 mm.

[0015] Therefore, when a user observes with both eyes, the image from 35° to the right to 25° to the right is observed with only the right eye, the image from 25° to 25° to the left is observed with both eyes, and the image from 25° to 35° to the left is observed with only the left eye, resulting in an overall horizontal angle of view of 70°. In this way, by displaying images with different angles of view to the left and right eyes so that only a portion of the angles of view overlaps between the left and right eyes, it is possible to observe an image with a wider angle of view than when images with the same angle of view are displayed to the left and right eyes when the display elements are the same size.

[0016] When widening the angle of view by displaying images with different angles of view to the left and right eyes and overlapping only a portion of the angle of view between the left and right eyes as in this embodiment, it is preferable that the angle of view (horizontal angle of view) of the binocular region is 40° or more. If the binocular region is smaller than 40°, the range that can be observed stereoscopically becomes narrow, making it impossible to observe naturally.

[0017] In this embodiment, the binocular region in the right eye observation image has a field angle of 50° and the right eye region has a field angle of 10°, and the ratio of the area of ​​the right eye observation image to the area of ​​the binocular region observation image is 25% according to the following formula (1).

[0018] (tan(35°)-tan(25°)) / (2×tan(25°))=0.25 …(1) This ratio is preferably 45% or less. If this ratio is greater than 45%, the boundary between the binocular region and the monocular region will be located near the center of the observed image, making the boundary more noticeable. In this case, the proportion of the binocular region is small, so the area available for stereoscopic viewing is narrow, and natural stereoscopic observation may not be possible. Furthermore, this ratio is preferably 10% or more. If this ratio is less than 10%, the monocular region is narrow, so the effect of widening the angle of view is small. That is, in this embodiment, the horizontal angle of view of the binocular region is 40° or more, and it is preferable to satisfy the condition 0.10≦A / B≦0.45, where A is the area of ​​the right eye region (monocular region) and B is the area of ​​the binocular region. The above also applies to the observed image of the left eye.

[0019] As shown in FIG. 2, the exit pupil EP of the eyepiece optical system of this embodiment is located at a distance of 28 mm, which is the sum of the eyeball rotation radius R of 10 mm and the eye relief E1 of 18 mm, and the exit pupil diameter D is 6 mm. This setting ensures that even when the eyeball rotates to observe up, down, left, or right, light from that direction is incident on the eyeball. The HMD is a head-mounted image display device (image observation device), and the eye relief E1 is preferably 15 mm or more so that users wearing eyeglasses can wear it. Furthermore, since a longer eye relief E1 would increase the outer dimensions of the lenses 104 and 105 and result in a larger image display device 101, the eye relief E1 is preferably 25 mm or less.

[0020] 3, the image display device 101 has an adjustment means (gradation correction means) 120. The adjustment means 120 has an adjustment means (120) that adjusts the brightness of an image (first image) displayed on the display element 107 and an image (second image) displayed on the display element 106.

[0021] Next, how an image is viewed by both eyes will be described with reference to Figures 4(a) and (b). Figure 4(a) is an explanatory diagram of how an image is viewed when images (observation images) with different angles of view are displayed to the left and right eyes and only a portion of the angle of view overlaps the left and right eyes. The image (second image) displayed on the display element 106 and the image (first image) displayed on the display element 107 are synthesized, and images in the left eye region, both eye region, and right eye region are observed.

[0022] In this embodiment, the first image has a first region and a second region, from the left to the right of the user. The second image has a third region and a fourth region, from the left to the right of the user. The second region of the first image and the third region of the second image are binocular regions that can be observed with both eyes of the user. The first region of the first image and the fourth region of the second image are monocular regions that can be observed with one eye of the user (first region: left eye region, fourth region: right eye region).

[0023] At this time, the boundary 401 between the left eye region (monocular region) and the binocular region, and the boundary 402 between the right eye region (monocular region) and the binocular region are observed as shown in Figure 4(b). This is thought to be caused by binocular rivalry between the left and right eyes, where an image is displayed in one eye but not in the other eye, and black areas such as the frame of the display element panel are seen.

[0024] For this reason, as shown in FIG. 5, in the binocular region of the display element 106, a luminance gradient (luminance change rate, gain change rate) is applied so that the luminance of the right eye display image decreases toward the boundary between the left eye region and the binocular region at the left end.

[0025] 5 is an explanatory diagram of a luminance gradient. As shown in FIG. 5, the adjustment means 120 decreases the luminance of the first image from a first position P1 in the second region of the first image to the right, and decreases the luminance of the second image from a second position P2 in the third region of the second image to the left. By applying such a luminance gradient to the image (second image), the adjustment means 120 can reduce the change in image brightness at the boundary between the left eye region and the binocular region, which is not displayed on the right eye display element 106, making the boundary difficult to observe, as shown in FIG. 4(b).

[0026] Similarly, a luminance gradient (luminance change rate, gain change rate) is applied so that the luminance of the left eye display image decreases toward the boundary between the right eye region and the binocular region at the right end within the binocular region of the display element 107. By applying such a luminance gradient to the image (first image), the adjustment means 120 can reduce the change in brightness of the image at the boundary between the right eye region and the binocular region, which is not displayed on the display element 107 for the left eye, making the boundary difficult to observe as shown in Figure 4(b).

[0027] Next, the shapes (effective optical diameters) of the lenses 104 and 105 that are the eyepiece optical system and the reduction in the amount of light in the displayed image will be described with reference to Figs. 7 to 9. Fig. 7 is an explanatory diagram of the lenses 104 and 105 in this embodiment. Fig. 8 is an explanatory diagram of the reduction in the amount of light in the displayed image due to the lenses 104 and 105 in this embodiment. Fig. 9 is an explanatory diagram of the gradation processing in this embodiment.

[0028] The image display device 101 of this embodiment has a nose relief portion and a forehead relief portion to prevent interference with the nose and forehead when worn by a user. Therefore, as shown in FIG. 7 , the lenses 104 and 105 have regions 1041, 1042, 1051, and 1052, each of which has an optical effective diameter (second effective diameter) smaller than the optical effective diameter (first effective diameter) of the other regions due to the nose relief portion and the forehead relief portion (part of the region is missing). The regions 1041 and 1042 (regions 1051 and 1052) have two second effective diameters that are asymmetrical in the horizontal direction. Because the effective diameters of the lenses 104 and 105 are small, the display image (right eye display image, second image) of the display element 106 and the display image (left eye display image, first image) of the display element 107 appear darker in the nose relief portion and the forehead relief portion, respectively, as shown in FIG. 8 .

[0029] In this case, if gradation correction such as that shown in Fig. 5 is performed on the display elements 106 and 107, the displayed image will be darker in the nose recess and forehead recess of the lenses 104 and 105, as shown in Fig. 8. This results in the displayed image being darker than the desired gradation. As a result, the darkness of the displayed image in the nose recess and forehead recess will be noticeable, which may prevent natural viewing.

[0030] Therefore, in this embodiment, the gradation area is adjusted taking into consideration that the displayed image becomes darker at the nose recess and forehead recess of the lenses 104 and 105. For example, as shown in Fig. 9, the gradation area, such as the start position (first position P1, second position P2) or width of the gradation at the nose recess and forehead recess of the lenses 104 and 105 and the gradation at other parts, is changed.

[0031] That is, the adjustment means 120 changes at least one of the first position P1 and the second position P2 according to the brightness of at least one of the first image and the second image. Preferably, when the brightness is darker than a predetermined brightness, the adjustment means 120 moves the first position P1 to the right and moves the second position P2 to the left.

[0032] In other words, the adjustment means 120 changes at least one of the first position P1 and the second position P2 in accordance with the optical effective diameter of at least one of the left eyepiece optical system and the right eyepiece optical system. Preferably, the optical effective diameter includes a first effective diameter and a second effective diameter smaller than the first effective diameter, and the adjustment means 120 moves the first position P1 rightward and moves the second position P2 leftward in the second effective diameter region with respect to the first effective diameter region.

[0033] The gradation on the display elements 106 and 107, combined with the reduction in light intensity due to the narrow effective diameter of the lenses 104 and 105, allows the image shown in Fig. 5 to be observed. As a result, the displayed image does not become too dark at the nose and forehead recesses of the lenses 104 and 105, allowing for natural viewing.

[0034] Because the HMD is a head-mounted image observation device, it is preferable that it be lightweight. For this reason, the lenses that make up the eyepiece optical system are preferably manufactured from a material such as resin, which has a lower specific gravity than glass. In this embodiment, the lenses 104 and 105 are both resin lenses. Furthermore, the lenses 104 and 105 are both aspherical lenses, which enhance the aberration correction effect.

[0035] The nose relief and forehead relief portions of the lenses 104 and 105 can be formed by cutting lenses molded in a circular shape. However, this embodiment is not limited to this, and the lenses 104 and 105 may each be molded with a notched shape as the nose relief and forehead relief portions. Molding the lenses in a shape that reflects the nose relief and forehead relief portions eliminates the need for post-cutting processing.

[0036] In this embodiment, the left-side display angle of view of the eyepiece optical system for the left eye is 35° horizontally, and the outer diameter of the left side of the lens 104 is 22 mm from the optical axis. If the lens 104 is circular and has a diameter of 22 mm, it will interfere with the user's nose and forehead, requiring nose relief and forehead relief sections, which means that the effective range of the lens must be narrowed by approximately 4 mm.

[0037] In this case, because the effective range of the lens is narrowed by the nose recess and forehead recess, the angle of view in those areas is 22°, which is inside the horizontal angle of view of the binocular area of ​​±25°. In that case, because the boundary between the binocular area and the monocular area is outside the angle of view of the nose recess and forehead recess, it is necessary to take into consideration that the displayed image will be dark in the nose recess and forehead recess, as in this embodiment.

[0038] The gradient of the light intensity reduction in the nose and forehead recesses of the lens is determined by the shape of the nose and forehead recesses and the exit pupil diameter of the eyepiece optical system, so it is preferable to change the gradation region, such as the start position or width of the gradation, accordingly.

[0039] In this case, to minimize the change in image brightness at the start of the gradation, it is preferable that the brightness gradient of the gradation at the start of the gradation be smaller than the brightness gradient at the center of the gradation width. In this embodiment, in areas other than the nose recess and forehead recess of the lens, the brightness gradient at the start of the gradation is 7% per 1° of display angle of view, and the brightness gradient at the center of the gradation width is 26% per 1° of display angle of view. It is preferable that the brightness gradient at the start of the gradation be 10% or less. By setting it in this way, the change in image brightness at the start of the gradation is minimized, resulting in a natural gradation.

[0040] Furthermore, to minimize changes in image brightness in the gradation near the boundary, it is preferable that the luminance gradient of the gradation near the boundary be smaller than the luminance gradient at the center of the gradation width. In this embodiment, with respect to the gradation in areas other than the nose recess and forehead recess of the lens, the luminance gradient near the boundary is 7% per 1° of display angle of view, and the luminance gradient at the center of the width is 26% per 1° of display angle of view. It is preferable that the luminance gradient of the gradation near the boundary be 15% or less. By setting it in this way, changes in image brightness in the gradation near the boundary are minimized, resulting in a natural gradation.

[0041] In this embodiment, the angle of view of the binocular region is 50° horizontally, and the region of the right eye observation image where the brightness of the displayed image is reduced is 20% of the area of ​​the binocular region. This ratio is preferably 40% or less. If this ratio is greater than 40%, the position where the brightness starts to decrease is near the center of the observation image, which may prevent natural observation. Furthermore, this ratio is preferably 5% or more. If this ratio is less than 5%, the brightness change becomes large and noticeable, which may prevent natural observation. The same applies to the left eye observation image.

[0042] In an ocular optical system having a binocular region and a monocular region as in this embodiment, the monocular region may be displayed in black to allow all displayed images to be viewed with both eyes, and the monocular region may be switched to be present or absent. In this case, the boundary between the binocular region and the monocular region disappears, making gradation processing unnecessary. The width of the monocular region may also be variable. The gradation region, such as the starting position or width of the gradation processing, may also be changed depending on the width of the monocular region.

[0043] Preferably, the rate of change in luminance per degree of horizontal display angle of view at the first position P1 or the second position P2 is smaller than the rate of change in luminance at the center of the luminance gradient region. Also preferably, the rate of change in luminance per degree of horizontal display angle of view at the first position P1 or the second position P2 is 10% or less. Also preferably, the rate of change in luminance per degree of horizontal display angle of view at the boundary between the binocular region and the monocular region is smaller than the rate of change in luminance at the center of the luminance gradient region. Also preferably, the rate of change in luminance per degree of horizontal display angle of view at the boundary between the binocular region and the monocular region is 15% or less.

[0044] Next, the inverse gamma correction of the luminance gradient will be described with reference to Figures 6(a) and 6(b), which are explanatory diagrams of the inverse gamma correction of the luminance gradient.

[0045] Generally, display elements have their own gamma values. Therefore, when a user is to view an image with a luminance gradient such as that shown in FIG. 5, the image displayed on the display element must be an image that has been subjected to inverse gamma correction in advance. A typical display element has a gamma value greater than 1. Therefore, when attempting to display an image with a luminance gradient such as that shown in FIG. 6(a), inverse gamma correction is performed to generate an image with a luminance gradient such as that shown in FIG. 6(b), which is used as the input image for the display element. As a result, the luminance gradient of the image displayed on the display element will be as shown in FIG. 6(a).

[0046] Furthermore, the eyepiece optical system has various aberrations, such as distortion and chromatic aberration of magnification. Therefore, the area where the luminance of the displayed image is reduced changes depending on the amount of aberration, such as distortion or chromatic aberration of magnification. Therefore, when the amount of distortion or chromatic aberration of magnification is large, it is necessary to correct the area where the luminance is reduced or the luminance gradient, taking into account the distortion or chromatic aberration of magnification, so that the image observed by the user has the desired luminance gradient.

[0047] The eyepiece optical system of this embodiment is composed of a single spherical lens (lenses 104 and 105), but an aspherical lens may also be used. Alternatively, an eyepiece optical system with higher optical performance may be constructed by using multiple lenses instead of a single lens. Furthermore, the display element of this embodiment is a self-luminous organic EL, but it may also be a transmissive liquid crystal element, a reflective liquid crystal element, or a DMD (Digital Micromirror Device). In this case, a light source and an illumination optical system are required.

[0048] In this embodiment, the display element is shifted outward to display images with different angles of view to the left and right eyes, and only a portion of the angle of view overlaps between the left and right eyes, but the eyepiece optical system and the display element may also be tilted as a unit. Even in this case, the same measures are taken to address the visibility of the boundary.

[0049] (Second embodiment) Next, an image display device (image observation device) 201 according to a second embodiment of the present invention will be described with reference to Fig. 10 to Fig. 12. Fig. 10 is an explanatory diagram of the image display device 201. Figs. 11 and 12 are explanatory diagrams of the eyepiece optical system of the image display device 201. In this embodiment, the image display device 201 is an HMD, but is not limited to this.

[0050] In FIG. 10, 201 is an image display device (HMD), 202 is the user's right eye, and 203 is the user's left eye. Lenses 204 and 205 constitute an eyepiece optical system for the right eye (second optical system). Lenses 206 and 207 constitute an eyepiece optical system for the left eye (first optical system). 208 is a display element (right eye display element, second display element), and 209 is a display element (left eye display element, first display element). Display elements 208 and 209 are each organic EL displays that emit unpolarized light.

[0051] The eyepiece optical system for the right eye enlarges and projects the original image displayed on the display element (display element for the right eye) 208 as a virtual image and directs it to the user's right eye 202. The eyepiece optical system for the left eye enlarges and projects the original image displayed on the display element (display element for the left eye) 209 as a virtual image and directs it to the user's left eye 203. The eye relief E2 of the image display device 201 is 15 mm.

[0052] The center of the display element 208 is shifted to the right with respect to a vertical cross section including the optical axis of the eyepiece optical system for the right eye, and the horizontal display angle of view of the eyepiece optical system for the right eye is 40° to the right and 24° to the left. The center of the display element 209 is shifted to the left with respect to a vertical cross section including the optical axis of the eyepiece optical system for the left eye, and the horizontal display angle of view of the eyepiece optical system for the left eye is 24° to the right and 40° to the left. The angles of view displayed by the eyepiece optical system for the right eye and the eyepiece optical system for the left eye are different from each other. The vertical display angle of view is 60°.

[0053] Therefore, when a user observes with both eyes, the image from 40° to 24° to the right is observed with only the right eye, the image from 24° to 24° to the left is observed with both eyes, and the image from 24° to 40° to the left is observed with only the left eye. The overall horizontal angle of view is 80°. In this way, images with different angles of view are displayed to the left and right eyes, and only a portion of the angles of view overlap. As a result, when the display elements are the same size, a wider angle of view can be observed than when images with the same angle of view are displayed to the left and right eyes.

[0054] When widening the angle of view by displaying images with different angles of view to the left and right eyes and overlapping only a portion of the angle of view between the left and right eyes as in this embodiment, it is preferable that the angle of view (horizontal angle of view) of the binocular region is 40° or more. If the binocular region is smaller than 40°, the range that can be observed stereoscopically becomes narrow, which may result in a loss of natural observation.

[0055] In this embodiment, the binocular region in the right eye observation image has a field angle of 48° and the right eye region has a field angle of 16°, and the ratio of the area of ​​the right eye observation image to the area of ​​the binocular region observation image is 35% according to the following formula (2).

[0056] (tan(40°)-tan(24°)) / (2×tan(24°))=0.44 …(2) This ratio is preferably 45% or less. If this ratio is greater than 45%, the boundary between the binocular region and the monocular region will be located near the center of the observed image, making the boundary more noticeable. Furthermore, since the ratio of the binocular region is small, the area available for stereoscopic viewing will be narrow, and natural stereoscopic observation may not be possible. Furthermore, this ratio is preferably 10% or more. If this ratio is less than 10%, the monocular region will be narrow and the effect of widening the angle of view will be small. This also applies to the image observed by the left eye.

[0057] The eyepiece optical system of this embodiment is an optical system that folds an optical path using polarized light, and this optical path will be described using an eyepiece optical system for the right eye. First, as shown in FIG. 11 , a polarizing plate 210 and a phase plate (first phase plate) 211 are arranged between a display element 208 and a lens 205, in that order from the display element 208 side, and a half mirror 212 is vapor-deposited on the surface of the lens 204 facing the lens 205. The surface on which the half mirror 212 is vapor-deposited functions as a transmissive / reflective surface. Furthermore, a phase plate (second phase plate) 213 and a PBS (polarization separation element) 214 are formed between the lens 204 and the user's right eye 202, in that order from the display element 208 side. The phase plate 213 and the PBS 214 each have a planar shape. The phase plates 211 and 213 are each a wave plate with a phase difference of λ / 4.

[0058] At this time, the slow axis of phase plate 211 is inclined at 45° with respect to the polarization direction of light transmitted through polarizing plate 210, and the slow axis of phase plate 213 is inclined at −45° with respect to the polarization direction of light transmitted through polarizing plate 210. The polarization direction of the first linearly polarized light transmitted through polarizing plate 210 and the polarization direction of the second linearly polarized light transmitted through PBS 214 are perpendicular to each other.

[0059] In this configuration, light emitted from the display element 208 passes through the polarizing plate 210 to become linearly polarized light, passes through the phase plate 211 to become circularly polarized light, passes through the half mirror 212 and the phase plate 213 to become linearly polarized light (first linearly polarized light). The polarization direction of this linearly polarized light is perpendicular to the polarization direction of the linearly polarized light (second linearly polarized light) passing through the PBS 214, so the light is reflected by the PBS 214 and passes through the phase plate 213 to become circularly polarized light. The light is then reflected by the half mirror 212 and passes through the phase plate 213 to become linearly polarized light. Unlike the above, the polarization direction of this linearly polarized light is the same as the polarization direction of the light passing through the PBS 214, so the light passes through the PBS 214 and is guided to the user's right eye 202. The above optical path is the same for the eyepiece optical system for the left eye.

[0060] By using polarized light to fold the optical path as in this embodiment, it is possible to make the optical system thin and shorten the focal length of the eyepiece optical system, thereby realizing image observation with a wide angle of view.

[0061] As shown in FIG. 12, the exit pupil EP of the eyepiece optical system of this embodiment is located at a distance of 25 mm, which is the sum of the eyeball rotation radius R of 10 mm and the eye relief E2 of 15 mm, and has an exit pupil diameter D of 6 mm. This setting ensures that even when the eyeball rotates to observe up, down, left, or right, light from that direction is incident on the eyeball. Since the HMD is a head-mounted image observation device, it is preferable that the eye relief E2 be 15 mm or greater so that users wearing eyeglasses can wear them. Furthermore, since a longer eye relief E1 increases the outer diameter of the lens and the size of the HMD, it is preferable that the eye relief E2 be 25 mm or less.

[0062] In this embodiment, as in Example 1, when observation images with different angles of view are displayed to the left and right eyes so that only a portion of the angles of view overlaps between the left and right eyes, the boundary between the left eye region and the both eye region, and the boundary between the right eye region and the both eye region are observed as shown in Figure 4(b).

[0063] For this reason, as shown in Fig. 5, in the binocular region of the display element 208, a luminance gradient is applied so that the luminance of the display image for the right eye decreases toward the boundary between the left eye region and the binocular region at the left end. By applying such a luminance gradient to the image (second image), the adjustment means 120 can reduce the change in brightness of the image at the boundary between the left eye region and the binocular region that is not displayed on the display element 208. As a result, the boundary becomes difficult to observe, as shown in Fig. 4(b).

[0064] Similarly, in the binocular region of the display element 209, a luminance gradient is applied so that the luminance of the left eye display image decreases toward the boundary between the right eye region and the binocular region at the right end. By applying such a luminance gradient to the image (first image), the adjustment means 120 can reduce the change in brightness of the image at the boundary between the right eye region and the binocular region, which is not displayed on the display element 209. As a result, the boundary becomes difficult to observe, as shown in FIG. 4(b).

[0065] The image display device 201 of this embodiment has a nose relief portion and a forehead relief portion so that the user does not get in the way of the nose or forehead when wearing the device. As shown in Fig. 7, the lenses 204, 205, 206, and 207 have regions with narrow effective diameters due to the nose relief portion and the forehead relief portion.

[0066] Because the HMD is a head-mounted image observation device, it is preferable that it be lightweight. For this reason, the lenses that make up the eyepiece optical system are preferably manufactured from resin, which has a lower specific gravity than glass. In this embodiment, the lenses 204 and 206 are both resin lenses. Furthermore, the lenses 204 and 206 are plano-convex aspherical lenses, which can enhance the aberration correction effect. Furthermore, the lenses 205 and 207 are both resin aspherical lenses.

[0067] The nose relief and forehead relief of the lenses 204 to 207 can be formed by cutting a circularly molded lens. However, this embodiment is not limited to this, and each of the lenses 204 to 207 may be molded with a notched shape as the nose relief and forehead relief. By molding the lenses in a shape that reflects the nose relief and forehead relief, post-cutting processing is not required.

[0068] In this embodiment, the angle of view of the binocular region is 48° horizontally, and the gradation region in which the brightness of the displayed image is reduced in the image observed by the right eye is 40% of the area of ​​the binocular region. This ratio is preferably 40% or less. If this ratio is greater than 40%, the position where the brightness starts to decrease is near the center of the observed image, which may prevent natural observation. Furthermore, this ratio is preferably 5% or more. If this ratio is less than 5%, the brightness change becomes large and noticeable, which may prevent natural observation. The above also applies to the image observed by the left eye.

[0069] Next, the gradation processing in this embodiment will be described with reference to Figures 13 and 14. Figures 13 and 14 are explanatory diagrams of the gradation processing.

[0070] This embodiment has a function to change the gradation area depending on the brightness of the displayed image. When the displayed image is bright, the gradation area is, for example, 40% of the area of ​​the binocular area, as shown in Fig. 13. On the other hand, when the displayed image is dark, the gradation area is, for example, 10% of the area of ​​the binocular area, as shown in Fig. 14, which is narrower than when the displayed image is bright.

[0071] When the displayed image is dark, the difference in brightness between the area where there is no displayed image is small. Therefore, the boundary between the binocular area and the monocular area is less noticeable than when the displayed image is bright. Therefore, when the displayed image is dark, the gradation area can be narrow. By narrowing the gradation area, the area where the light intensity decreases is narrowed, allowing for a more natural viewing experience.

[0072] In this embodiment, when the average brightness of the display image is 50% or more, the gradation area is 40% of the binocular area. On the other hand, when the average brightness is less than 50%, the gradation area is 10% of the binocular area. The brightness of the display image can be determined using the average grayscale value of the display image, or the maximum grayscale value may be used. Furthermore, the brightness may be calculated from the grayscale value of the display image near the boundary between the binocular area and the monocular area, rather than the grayscale value of the entire display image.

[0073] The gradation area may be changed in two or more stages depending on the brightness of the displayed image. For example, the gradation area may be set to 40% of the binocular area when the brightness is 75% or higher, 30% when the brightness is 50% or higher, 20% when the brightness is 25% or higher, and 10% when the brightness is less than 25%.

[0074] In this embodiment, the surface on which the half mirror 212 is vapor-deposited has a convex shape facing the display element 208. By vapor-depositing the half mirror on this convex surface, it is possible to achieve a wide angle of view while reducing the thickness of the optical system. In addition, by making the convex surface on which the half mirror 212 is vapor-deposited aspherical, it is possible to improve the aberration correction effect.

[0075] The surface of the lens 204 on which the phase plate 213 and the PBS 214 are formed, facing the user's eyeball, is flat. This is to achieve both a long eye relief and a slim optical system. For this reason, the lens 204 is a plano-convex lens.

[0076] In this embodiment, the phase plates 211 and 213 are each a wave plate with a phase difference of λ / 4, but the phase difference may be shifted from λ / 4 to cancel the birefringence of the lenses 204 and 205. In this case, it is preferable that the sum of the phase differences between the lens 204 and the phase plate 213 is 3λ / 20 or more and 7λ / 20 or less. It is also preferable that the sum of the phase differences between the lens 205 and the phase plate 211 is 3λ / 20 or more and 7λ / 20 or less. Outside this range, the intensity of ghost light increases, which may prevent natural observation.

[0077] In this embodiment, the display element is an organic EL element that emits unpolarized light, but a liquid crystal display may be used to emit linearly polarized light. This configuration eliminates the need for a polarizing plate 210 on the display element side, making it possible to reduce thickness and costs.

[0078] (Third embodiment) Next, an image display device (image observation device) 301 according to a third embodiment of the present invention will be described with reference to Fig. 15 to Fig. 17. Fig. 15 is an explanatory diagram of the image display device 301. Figs. 16 and 17 are explanatory diagrams of the eyepiece optical system of the image display device 301. In this embodiment, the image display device 301 is an HMD, but is not limited to this.

[0079] In FIG. 15, 301 is an image display device (HMD), 302 is the user's right eye, and 303 is the user's left eye. A cemented lens formed by cementing lenses 304 and 305 together constitutes an eyepiece optical system for the right eye (second optical system). A cemented lens formed by cementing lenses 306 and 307 constitutes an eyepiece optical system for the left eye (first optical system). 308 is a display element (right eye display element, second display element), and 309 is a display element (left eye display element, first display element). Each of the display elements 308 and 309 is an organic EL display.

[0080] The eyepiece optical system for the right eye enlarges and projects the original image displayed on the display element 308 as a virtual image and directs it to the user's right eye 302. The eyepiece optical system for the left eye enlarges and projects the original image displayed on the display element 309 as a virtual image and directs it to the user's left eye 303.

[0081] The eye relief E3 of the image display device 301 is 20 mm. The exit pupil EP of the eyepiece optical system of this embodiment is located at a position of 30 mm, which is the sum of the eye relief E3 = 20 mm and the radius of rotation R = 10 mm of the eyeball, as shown in Fig. 17, and the exit pupil diameter D = 6 mm. With this setting, even when the eyeball rotates to observe up, down, left, or right, light in that direction enters the eyeball.

[0082] The center of the display element 308 is shifted to the right with respect to a vertical cross section including the optical axis of the eyepiece optical system for the right eye, and the horizontal display angle of view of the eyepiece optical system for the right eye is 40° to the right and 30° to the left. The center of the display element 309 is shifted to the left with respect to a vertical cross section including the optical axis of the eyepiece optical system for the left eye, and the horizontal display angle of view of the eyepiece optical system for the left eye is 30° to the right and 40° to the left. The angles of view displayed by the eyepiece optical system for the right eye and the eyepiece optical system for the left eye are different from each other. The vertical display angle of view is 60°.

[0083] Therefore, when a user observes with both eyes, the image from 40° to the right to 30° to the right is observed with only the right eye, the image from 30° to the right to 30° to the left is observed with both eyes, and the image from 30° to 40° to the left is observed with only the left eye, resulting in an overall horizontal angle of view of 80°. In this way, images with different angles of view are displayed to the left and right eyes, and only a portion of the angles of view overlap between the left and right eyes. This allows a wider angle of view to be observed than when images with the same angle of view are displayed to the left and right eyes, assuming that the display elements are the same size.

[0084] When widening the angle of view by displaying images with different angles of view to the left and right eyes and overlapping only a portion of the angle of view between the left and right eyes as in this embodiment, it is preferable that the angle of view (horizontal angle of view) of the binocular region is 40° or more. If the binocular region is smaller than 40°, the range that can be observed stereoscopically becomes narrow, and natural observation may not be possible.

[0085] In this embodiment, in the right eye observation image, the binocular region has a field angle of 60° and the right eye region has a field angle of 10°. The ratio of the area of ​​the right eye observation image to the area of ​​the binocular region observation image is 23% according to the following formula (3).

[0086] (tan(40°)-tan(30°)) / (2×tan(30°))=0.23 …(3) This ratio is preferably 45% or less. If this ratio is greater than 45%, the boundary between the binocular region and the monocular region will be located near the center of the observed image, making the boundary more noticeable. Furthermore, since the ratio of the binocular region is small, the region available for stereoscopic viewing will be narrow, and natural stereoscopic observation may not be possible. Furthermore, this ratio is preferably 10% or more. If this ratio is less than 10%, the monocular region will be narrow, and the effect of widening the angle of view will be small. The same applies to the image observed by the left eye.

[0087] The eyepiece optical system of this embodiment is an optical system that folds the optical path using polarized light, and this optical path will be described using an eyepiece optical system for the right eye. First, as shown in FIG. 16 , a polarizing plate 310 and a phase plate (first phase plate) 311 are arranged, in that order from the display element 308 side, between the display element 308 and the lens 305, and a half mirror 312 is vapor-deposited on the surface of the lens 304 facing the lens 305. The surface on which the half mirror 312 is vapor-deposited functions as a transmissive / reflective surface. Furthermore, a phase plate (second phase plate) 313 and a polarization splitter PBS 314 are formed, in that order from the display element 308 side, between the lens 304 and the user's right eye 302. The phase plate 313 and the polarization splitter PBS 314 are planar. The phase plate 311 and the phase plate 313 are wave plates with a phase difference of λ / 4.

[0088] At this time, the slow axis of phase plate 311 is inclined at 45° with respect to the polarization direction of light transmitted through polarizing plate 310, and the slow axis of phase plate 313 is inclined at −45° with respect to the polarization direction of light transmitted through polarizing plate 310. The polarization direction of the first linearly polarized light transmitted through polarizing plate 310 and the polarization direction of the second linearly polarized light transmitted through PBS 314 are perpendicular to each other.

[0089] In this configuration, light emitted from the display element 308 passes through the polarizing plate 310 to become linearly polarized light, passes through the phase plate 311 to become circularly polarized light, passes through the half mirror 312 and the phase plate 313 to become linearly polarized light (first linearly polarized light). The polarization direction of this linearly polarized light is perpendicular to the polarization direction of the linearly polarized light (second linearly polarized light) that passes through the PBS 314. Therefore, the linearly polarized light is reflected by the PBS 314 and passes through the phase plate 313 to become circularly polarized light. The circularly polarized light is reflected by the half mirror 312 and passes through the phase plate 313 to become linearly polarized light. Unlike the above, the polarization direction of this linearly polarized light matches the polarization direction that passes through the PBS 314. Therefore, the linearly polarized light passes through the PBS 314 and is guided to the user's right eye 302. The above optical path is similar for the eyepiece optical system for the left eye.

[0090] In this embodiment, a polarizing plate may be placed between the PBS 314 and the user's eyeball in order to reduce ghost light from external light and increase the contrast of the observed image.

[0091] By using polarized light to fold the optical path as in this embodiment, it is possible to make the optical system thin and shorten the focal length of the eyepiece optical system, thereby realizing image observation with a wide angle of view.

[0092] In this embodiment, as in Example 1, when observation images with different angles of view are displayed to the left and right eyes and only a portion of the angles of view overlaps between the left and right eyes, the boundaries between the left eye region and the both eye region and the right eye region are observed as shown in Figure 4(b).

[0093] For this reason, as shown in Fig. 5, in the binocular region of the display element 308, a luminance gradient is applied so that the luminance of the display image for the right eye decreases toward the boundary between the left eye region and the binocular region at the left end. By applying such a luminance gradient to the image (second image), the adjustment means 120 can reduce the change in brightness of the image at the boundary between the left eye region and the binocular region, which is not displayed on the display element 308. For this reason, the boundary becomes difficult to observe, as shown in Fig. 4(b).

[0094] Similarly, in the binocular region of the display element 309, a luminance gradient is applied so that the luminance of the display image for the left eye decreases toward the boundary between the right eye region and the binocular region at the right end. By applying such a luminance gradient to the image (first image), the adjustment means 120 can reduce the change in brightness of the image at the boundary between the right eye region and the binocular region, which is not displayed on the display element 309, making the boundary difficult to observe as shown in Figure 4(b).

[0095] The image display device 301 of this embodiment has a nose recess and a forehead recess so that the user's nose and forehead do not interfere with the display when wearing the device. Therefore, the lenses 304 and 305 have areas where the effective diameter is narrow due to the nose recess and forehead recess, as shown in Fig. 7. Because the effective diameter of the lenses is narrow, the displayed image becomes dark in the nose recess and forehead recess, as shown in Fig. 8.

[0096] In this case, if gradation correction as shown in Figure 5 is performed on the display element, the displayed image will be darker at the nose and forehead recesses of the lens, making the displayed image darker than the desired gradation. As a result, the darkness of the displayed image at the nose and forehead recesses will be noticeable, and natural viewing may not be possible.

[0097] Therefore, in this embodiment, as in Example 1, taking into consideration that the displayed image becomes dark in the nose recess and forehead recess of the lens, the start position and width of the gradation in the nose recess and forehead recess of the lens and the gradation in other parts are changed as shown in Fig. 9. As a result, the gradation on the display element and the reduction in light amount due to the narrow effective area of ​​the lens overlap, making it possible to observe an image such as that shown in Fig. 5, and the displayed image can be viewed naturally without becoming too dark in the nose recess and forehead recess of the lens.

[0098] Because the HMD is a head-mounted image observation device, it is preferable that it be lightweight. Therefore, it is preferable that the lenses that make up the eyepiece optical system are manufactured from resin, which has a lower specific gravity than glass. In this embodiment, the lenses 304, 305, 306, and 307 are resin lenses. Furthermore, the lenses 304, 305, 306, and 307 are aspherical lenses, which can improve the aberration correction effect.

[0099] In this embodiment, the lenses 304 and 305 are cemented lenses, and the lenses 306 and 307 are also cemented lenses. Using cemented lenses makes it easier to hold the lenses. For this reason, the surface of the lens 305 on which the half mirror 312 is vapor-deposited may be the surface facing the user's right eye 302. Even in this case, the surface on which the half mirror is vapor-deposited has a convex shape facing the display element 308.

[0100] The nose relief and forehead relief of the lenses 304 to 307 can be formed by cutting a circularly molded lens. However, this embodiment is not limited to this, and each of the lenses 304 to 307 may be molded with a notched shape as the nose relief and forehead relief. By molding the lenses in a shape that reflects the nose relief and forehead relief, post-cutting processing is not required.

[0101] In this embodiment, the left-side display angle of view of the eyepiece optical system for the left eye is 40° horizontally, and the outer diameter of the left side of the lens 304 is 25 mm from the optical axis. If the lens 304 were circular and had a diameter of 25 mm, it would interfere with the user's nose and forehead, requiring nose relief and forehead relief sections, which means that the effective range of the lens needs to be narrowed by about 6 mm.

[0102] In this case, because the effective range of the lens is narrow in the nasal recess and forehead recess, the angle of view in those areas is 24°, which is inside the horizontal angle of view of the binocular area of ​​±30°. In that case, because the boundary between the binocular area and the monocular area is outside the angle of view of the nasal recess and forehead recess, it is necessary to take into account that the displayed image will be dark in the nasal recess and forehead recess, as in this embodiment.

[0103] At this time, in order to minimize the change in image brightness at the start position of the gradation, it is preferable that the brightness gradient of the gradation at the start position is smaller than the brightness gradient at the center of the gradation width. In this embodiment, for the gradation in areas other than the nose recess and forehead recess of the lens, the brightness gradient at the start position is 5% per 1° of display angle of view, and the brightness gradient at the center of the width is 30% per 1° of display angle of view. It is preferable that the brightness gradient at the gradation start position is 10% or less. By doing so, the change in image brightness at the gradation start position is minimized, resulting in a natural gradation.

[0104] Furthermore, to minimize changes in image brightness in the gradation near the boundary, it is preferable that the luminance gradient of the gradation near the boundary be smaller than the luminance gradient at the center of the gradation width. In this embodiment, the gradation in areas other than the nose recess and forehead recess of the lens has a luminance gradient near the boundary of 13% per 1° of display angle of view, and a luminance gradient at the center of the width of 30% per 1° of display angle of view. It is preferable that the luminance gradient of the gradation near the boundary be 15% or less. This minimizes changes in image brightness in the gradation near the boundary, resulting in a natural gradation.

[0105] In this embodiment, the horizontal field angle of the binocular region is 60°, and the gradation region in the image observed by the right eye, which reduces the brightness of the displayed image, is 10% of the area of ​​the binocular region. This ratio is preferably 15% or less when the field angle of the binocular region is greater than 55°. When the field angle of the binocular region is greater than 55°, the boundary between the binocular region and the monocular region is outside the displayed image, making the boundary less noticeable. Therefore, narrowing the gradation region can reduce the area where the displayed image becomes dark. Furthermore, this ratio is preferably 5% or more. When this ratio is less than 5%, the luminance change becomes large and noticeable, which may prevent natural viewing. That is, when the area of ​​the luminance gradient region leading to the first or second exit pupil is C, preferably, the conditional expression 0.05≦C / B≦0.40 is satisfied. More preferably, the horizontal field angle of the binocular region is 55° or greater, and the conditional expression 0.05≦C / B≦0.15 is satisfied. The same applies to the image observed by the left eye.

[0106] In this embodiment, as in Example 2, there is a function to change the gradation area depending on the brightness of the displayed image. When the displayed image is bright, the gradation area is, for example, 10% of the area of ​​the binocular area. On the other hand, when the displayed image is dark, the gradation area is, for example, 5% of the binocular area, which is narrower than when the displayed image is bright.

[0107] In each embodiment, the adjustment unit 120 may be configured to be able to change the binocular region or the monocular region. In this case, the adjustment unit 120 may be configured to change at least one of the first position P1 or the second position P2 depending on the horizontal angle of view of the binocular region or the horizontal angle of view of the monocular region.

[0108] According to each embodiment, an image display device can be provided that can display natural images in which the boundary between the monocular area and the binocular area is not noticeable when displaying images with different angles of view to the left and right eyes.

[0109] The disclosure of each embodiment includes the following configuration. (Configuration 1) a first display element and a second display element; a first optical system and a second optical system that respectively guide a first image displayed on the first display element and a second image displayed on the second display element to a first exit pupil and a second exit pupil corresponding to the left and right eyes of a user; an adjusting means for adjusting the brightness of each of the first image and the second image, the first image has a first region and a second region in order from the left to the right of the user; the second image has, in order from the left to the right of the user, a third region and a fourth region; the second region of the first image and the third region of the second image are binocular regions observable with both eyes of a user, the first region of the first image and the fourth region of the second image are monocular regions observable with one eye of a user, The adjusting means is Decreasing the brightness of the first image from a first position in the second region of the first image to a right direction, and decreasing the brightness of the second image from a second position in the third region of the second image to a left direction; 1. An image display device, comprising: an image display device that changes at least one of the first position and the second position in accordance with brightness of at least one of the first image and the second image. (Configuration 2) The image display device according to configuration 1, wherein the adjustment means moves the first position to the right and moves the second position to the left when the brightness is darker than a predetermined brightness. (Configuration 3) a first display element and a second display element; a first optical system and a second optical system that respectively guide a first image displayed on the first display element and a second image displayed on the second display element to a first exit pupil and a second exit pupil corresponding to the left and right eyes of a user; an adjusting means for adjusting the brightness of each of the first image and the second image, the first image has a first region and a second region in order from the left to the right of the user; the second image has, in order from the left to the right of the user, a third region and a fourth region; the second region of the first image and the third region of the second image are binocular regions observable with both eyes of a user, the first region of the first image and the fourth region of the second image are monocular regions observable with one eye of a user, The adjusting means is Decreasing the brightness of the first image from a first position in the second region of the first image to a right direction, and decreasing the brightness of the second image from a second position in the third region of the second image to a left direction; 1. An image display device, wherein at least one of the first position and the second position is changed according to an optical effective diameter of at least one of the first optical system and the second optical system. (Configuration 4) the optical effective diameter includes a first effective diameter and a second effective diameter smaller than the first effective diameter, The image display device described in configuration 3, wherein the adjustment means moves the first position to the right and the second position to the left in the second effective diameter region with respect to the first effective diameter region. (Configuration 5) 5. The image display device according to configuration 4, wherein the second effective diameter is located at a field angle inside a boundary between the binocular area and the monocular area. (Configuration 6) 6. The image display device according to configuration 4 or 5, wherein the first optical system and the second optical system each have two second effective diameters asymmetric with respect to the horizontal direction. (Configuration 7) 7. The image display device according to any one of configurations 4 to 6, wherein the adjusting means changes the gradient of the luminance in accordance with a decrease in the amount of light in the region of the second effective diameter. (Configuration 8) 8. The image display device according to any one of configurations 3 to 7, wherein the adjustment means changes at least one of the first position and the second position depending on the brightness of at least one of the first image and the second image. (Configuration 9) The horizontal angle of view of the binocular region is 40° or more, When the area of ​​the first area or the fourth area of ​​the monocular area is A and the area of ​​the binocular area is B, 0.10≦A / B≦0.45 9. The image display device according to any one of configurations 1 to 8, wherein the following condition is satisfied: (Configuration 10) 10. The image display device according to any one of configurations 1 to 9, wherein the rate of change in luminance per degree of horizontal display angle of view at the first position or the second position is smaller than the rate of change in luminance at the center position of the luminance gradient area. (Configuration 11) 11. The image display device according to any one of configurations 1 to 10, wherein a rate of change in luminance per degree of horizontal display angle of view at the first position or the second position is 10% or less. (Configuration 12) An image display device according to any one of configurations 1 to 11, characterized in that the luminance change rate per 1° of horizontal display angle of view at the boundary between the binocular area and the monocular area is smaller than the luminance change rate at the center position of the luminance gradient area. (Configuration 13) 13. The image display device according to any one of configurations 1 to 12, wherein a rate of change in luminance per degree of horizontal display angle of view at a boundary between the binocular area and the monocular area is 15% or less. (Configuration 14) When the area of ​​the binocular region is B and the area of ​​the luminance gradient region guided to the first exit pupil or the second exit pupil is C, 0.05≦C / B≦0.40 14. The image display device according to any one of configurations 1 to 13, wherein the following condition is satisfied: (Configuration 15) The horizontal angle of view of the binocular region is 55° or more, 0.05≦C / B≦0.15 15. The image display device according to configuration 14, wherein the following condition is satisfied: (Configuration 16) The adjusting means is The binocular region or the monocular region is changeable; 16. The image display device according to any one of configurations 1 to 15, wherein at least one of the first position and the second position is changed depending on the horizontal angle of view of the binocular region or the horizontal angle of view of the monocular region. (Configuration 17) The image display device described in any one of configurations 1 to 16, characterized in that the first optical system and the second optical system each have, in order from the display element toward the first exit pupil and the second exit pupil, a first phase plate, a transmissive-reflective surface, a second phase plate, and a polarization separation element that reflects first linearly polarized light and transmits second linearly polarized light having a polarization direction perpendicular to the polarization direction of the first linearly polarized light.

[0110] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. [Explanation of symbols]

[0111] 101, 201, 301 Image display device 102, 202, 302 Right eye (second exit pupil) 103, 203, 303 Left eye (1st exit pupil) 104, 204, 205, 304, 305 Lens (Second optical system) 105, 206, 207, 306, 307 Lenses (first optical system) 106, 208, 308 Display element (second display element) 107, 209, 309 Display element (first display element) 120 Adjustment means

Claims

1. a first display element and a second display element; a first optical system and a second optical system that respectively guide a first image displayed on the first display element and a second image displayed on the second display element to a first exit pupil and a second exit pupil corresponding to the left and right eyes of a user; an adjusting unit for adjusting the brightness of each of the first image and the second image; the first image has a first region and a second region in order from the left to the right of the user; the second image has, in order from the left to the right of the user, a third region and a fourth region; the second region of the first image and the third region of the second image are binocular regions observable with both eyes of a user, the first region of the first image and the fourth region of the second image are monocular regions observable with one eye of a user, The adjusting means is Decreasing the brightness of the first image from a first position in the second region of the first image to a right direction, and decreasing the brightness of the second image from a second position in the third region of the second image to a left direction; An image display device, characterized in that at least one of the first position and the second position is changed in accordance with brightness of at least one of the first image and the second image.

2. 2. The image display device according to claim 1, wherein the adjustment means moves the first position rightward and the second position leftward when the brightness is lower than a predetermined brightness.

3. a first display element and a second display element; a first optical system and a second optical system that respectively guide a first image displayed on the first display element and a second image displayed on the second display element to a first exit pupil and a second exit pupil corresponding to the left and right eyes of a user; an adjusting unit for adjusting the brightness of each of the first image and the second image; the first image has a first region and a second region in order from the left to the right of the user; the second image has, in order from the left to the right of the user, a third region and a fourth region; the second region of the first image and the third region of the second image are binocular regions observable with both eyes of a user, the first region of the first image and the fourth region of the second image are monocular regions observable with one eye of a user, The adjusting means is Decreasing the brightness of the first image from a first position in the second region of the first image to a right direction, and decreasing the brightness of the second image from a second position in the third region of the second image to a left direction; 10. An image display device, comprising: an image display device that changes at least one of the first position and the second position in accordance with an effective optical diameter of at least one of the first optical system and the second optical system.

4. the optical effective diameter includes a first effective diameter and a second effective diameter smaller than the first effective diameter, 4. The image display device according to claim 3, wherein the adjustment means moves the first position rightward and the second position leftward in the second effective diameter region with respect to the first effective diameter region.

5. 5. The image display device according to claim 4, wherein the second effective diameter is located at a field angle inside a boundary between the binocular area and the monocular area.

6. 5. The image display device according to claim 4, wherein the first optical system and the second optical system each have two second effective diameters asymmetric with respect to the horizontal direction.

7. 5. The image display device according to claim 4, wherein the adjusting means changes the gradient of the luminance in accordance with a decrease in the amount of light in the region of the second effective diameter.

8. 4. The image display device according to claim 3, wherein the adjustment means changes at least one of the first position and the second position in accordance with brightness of at least one of the first image and the second image.

9. the horizontal angle of view of the binocular region is 40° or more; When the area of ​​the first area or the fourth area of ​​the monocular area is A and the area of ​​the binocular area is B, 0.10≦A / B≦0.45 9. The image display device according to claim 1, wherein the following condition is satisfied:

10. 9. The image display device according to claim 1, wherein a luminance change rate per degree of horizontal display angle of view at the first position or the second position is smaller than a luminance change rate at a center position of a luminance gradient area.

11. 9. The image display device according to claim 1, wherein a rate of change in luminance per degree of horizontal display angle of view at the first position or the second position is 10% or less.

12. The image display device according to any one of claims 1 to 8, characterized in that the luminance change rate per 1° of horizontal display angle of view at the boundary between the binocular area and the monocular area is smaller than the luminance change rate at the center position of the luminance gradient area.

13. 9. The image display device according to claim 1, wherein a luminance change rate per degree of horizontal display angle of view at a boundary between the binocular area and the monocular area is 15% or less.

14. When the area of ​​the binocular region is B and the area of ​​the luminance gradient region guided to the first exit pupil or the second exit pupil is C, 0.05≦C / B≦0.40 9. The image display device according to claim 1, wherein the following condition is satisfied:

15. the horizontal angle of view of the binocular region is 55° or more; 0.05≦C / B≦0.15 15. The image display device according to claim 14, wherein the following condition is satisfied:

16. The adjusting means is The binocular region or the monocular region is changeable; 9. The image display device according to claim 1, wherein at least one of the first position and the second position is changed depending on a horizontal angle of view of the binocular region or a horizontal angle of view of the monocular region.

17. 9. An image display device as claimed in any one of claims 1 to 8, characterized in that the first optical system and the second optical system each have, in order from the display element towards the first exit pupil and the second exit pupil, a first phase plate, a transmissive / reflective surface, a second phase plate, and a polarization separation element that reflects first linearly polarized light and transmits second linearly polarized light having a polarization direction perpendicular to the polarization direction of the first linearly polarized light.

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