Image display device

Abstract

To provide an image display apparatus which reduces a sense of discomfort due to a frame in the time of observation by a user while securing the strength of the frame holding an optical component and a display device.SOLUTION: An image display apparatus which superimposes an image on a first light flux passing through a display optical system includes a frame which holds the periphery of the display optical system on a plane intersecting an optical axis that guides the first light flux of the display optical system. The frame has such a shape that, in at least a portion thereof, the side on which the first light flux in the direction in parallel to the optical axis is emitted from the display optical system is arranged at a position closer to the optical axis with respect to the side on which the first light flux is incident on the display optical system, and the width in the direction orthogonal to the optical axis is narrow.SELECTED DRAWING: Figure 5

Description

Technical Field

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

Background Art

[0002] Among image display devices that cover a user's (observer's) head or face and display an image in front of the user's eyes, there are some that realize AR (augmented reality) or MR (mixed reality) experiences by displaying a subject image and superimposing a CG video at the same time. Such image display devices are utilized in fields such as entertainment, work support, and training.

[0003] In recent years, due to the demand for higher performance and more functions in such image display devices, the required level of the optical performance of lenses and prisms mounted on the image display devices has increased, and the number of lens components and the lens weight have been increasing. Also, the required level of the pixel count of the display device has increased, and the size and weight of the display device have been increasing. Therefore, the frame that holds the optical components and the display device has been increasing in size to improve its strength.

[0004] Therefore, in Patent Document 1, a shape that is excellent in design is proposed by arranging a specific part of the frame close to the nose, thereby reducing the weight of the frame and suppressing the visual volume.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] On the other hand, as the frame size increases, the frame becomes more noticeable between the subject viewed through the display device and the subject visible outside the display device, creating a sense of unease for the user during observation. However, Patent Document 1 does not address the sense of unease that users experience when looking outside the display device.

[0007] The objective of the present invention is to provide an image display device that ensures the strength of the frame that holds optical components and display devices, while reducing the discomfort caused by the frame during user observation. [Means for solving the problem]

[0008] To achieve the above objective, the present invention provides an image display device that superimposes an image onto a first light beam passing through a display optical system, the image display device having a frame that holds the display optical system in a plane intersecting the optical axis that guides the first light beam of the display optical system, the image display device being wearable by a user, the display optical system being positioned in front of the user's eyes when the image display device is worn, and the frame being within the user's field of view when the image display device is worn. The display optical system does not transmit light. The frame is provided such that it includes an area in which a light beam passing outside the frame is visible, and the frame is characterized in that at least a portion of it is positioned closer to the optical axis on the side where the first light beam exits the display optical system in a direction parallel to the optical axis than on the side where the first light beam enters the display optical system, and has a narrower width in the direction perpendicular to the optical axis. [Effects of the Invention]

[0009] According to the present invention, it is possible to provide an image display device that ensures the strength of the frame that holds optical components and display devices while reducing the discomfort caused by the frame during user observation. [Brief explanation of the drawing]

[0010] [Figure 1] This is an external perspective view of an AR device according to an embodiment of the present invention. [Figure 2] This figure shows details of the display optical system 103 and its peripheral components of an AR device 100 according to an embodiment of the present invention. [Figure 3] This is a schematic diagram showing the field of view of an object image viewed through an AR device that does not implement the present invention, as a comparative example. [Figure 4] This is a horizontal cross-sectional view showing the display optical system 1003 and its peripheral components of an AR device that does not implement the present invention, as a comparative example. [Figure 5] This is a horizontal cross-sectional view of the display optical system 103 and frame 104 of an AR device 100 according to an embodiment of the present invention. [Figure 6] This is a schematic diagram showing the field of view of a subject image viewed through an AR device 100 according to an embodiment of the present invention. [Modes for carrying out the invention]

[0011] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0012] Figure 1 is an external perspective view of a glasses-type AR (augmented reality) device 100, which is an image display device according to an embodiment of the present invention. In Figure 1, 101 is the front cover and 102 is the rear cover, and various components are housed in these members. 103 is a display optical system capable of displaying a CG image superimposed on a subject image, and 104 is a frame that holds the display optical system 103. In this embodiment, the frame 104 is rectangular in shape and holds the display optical system 130 in a plane that intersects with the optical path 203, which will be described later, but it may also be circular or a shape that combines straight lines and curves, or a shape that does not hold a part of the display optical system 103.

[0013] The front cover 101 is provided with ear loops 105 on both the left and right sides for attaching the AR device 100 to the user's head or face. The rear cover 102 is provided with a nose rest 106 for supporting the AR device 100 on the user's nose.

[0014] Figure 2 shows details of the display optical system 103 and its peripheral components of an AR device 100 according to an embodiment of the present invention. Figure 2(a) is a vertical cross-sectional view of the display optical system 103 and its peripheral components of the AR device 100, and Figure 2(b) is a horizontal cross-sectional view of the display optical system 103 and its peripheral components of the AR device 100. 201 is a CG display device for projecting CG images and is composed of an organic EL display or the like. 1031, 1032, and 1034 are lenses that constitute the display optical system, and 1033 is a half-mirror surface provided on the display optical system lens 1032. 202 is a CG optical path for displaying the projected image from the display device 201 to the eye. 203 is the optical path when viewing the subject image through the display optical system. The CG optical path 202 takes the path of light reflected by the half-mirror surface 1033, and the subject optical path 203 takes the path of light transmitted through this half-mirror surface 1033, so that the subject image and the CG image are superimposed and enter the user's eye via the display optical system 103. Specifically, the surface of lens 1031 facing the subject is the first incident part into which the first light beam is incident, and the surface of lens 1032 facing the CG display device 201 is the second incident part into which the second light beam from the CG display device 201 is incident. The surface of lens 1034 facing the user is the output part that emits the first and second light beams. The half-mirror surface 1033 transmits the first light beam incident from the first incident part and reflects the second light beam incident from the second incident part toward the output part. The optical path 203 is the optical axis that guides the first light beam of the display optical system 103.

[0015] The lenses 1031, 1032, 1034 and the CG display device 201 that constitute the display optical system 103 are held in the frame 104. For example, the CG display device 201 is held inside the frame 14, and the CG image displayed on the CG display device 201 is guided to the lenses 1031, 1032, and 1034 through an opening provided in the frame 104. The frame 104 is also held in the rear cover 102. The frame 104 may be configured to be movable relative to the rear cover 102 in a known manner for interpupillary distance adjustment.

[0016] Also, as shown in FIG. 2(b), the lenses 1031, 1032, 1034 and the frame 14 become wider as they go from the observer side toward the subject side. The description of the structures of the lenses 1031, 1032, 1034 and the frame 14 will be given later.

[0017] FIG. 3 is a schematic view showing a visual field of seeing a subject image through an AR device not implementing the present invention as a comparative example. The frame 104 of the AR device 100 according to the embodiment of the present invention and the frame 1004 shown in FIG. 3 have different shapes.

[0018] 301 shows the visual field when seeing the subject and corresponds to the entire visual field of the user. 302 shows the superimposed CG image. In FIG. 3, the frame 1004 can be seen in the visual field, and inside the frame 1004, the subject image seen through the AR device and the CG image 302 are displayed, and outside the frame 1004, the subject seen without passing through the AR device can be seen. Compared with general glasses, as the AR device is accompanied by high performance and large size of the display device for displaying the CG image and large size of the display optical system for ensuring optical performance, improvement in the strength of the frame for holding components is desired.

[0019] FIG. 4 is a horizontal cross-sectional view showing the display optical system 1003 of an AR device not implementing the present invention as a comparative example and its peripheral components. The display optical system 103 of the AR device 100 according to the embodiment of the present invention and the display optical system 1003 shown in FIG. 4 have different shapes.

[0020] 4010 indicates the inner wall of the frame 1004, and 4020 indicates the outer wall of the frame 1004. 501 indicates the pupil of the user's eye. In an AR device that displays transmitted light from a subject or an MR device that displays an image of an angular field corresponding to the transmitted light, the display optical system 103 generally has a viewing angle α in a direction spreading from the pupil 501. The viewing angle α is an area where the transmitted light from the subject in the AR device or the image of the angular field corresponding to the transmitted light in the MR device and the projected image from the CG display device are superimposed and displayed. Between the frame inner angle β determined as the minimum angle among the straight lines connecting the eye pupil 501 and the inner wall 4010, and the frame outer angle γ determined as the maximum angle among the straight lines connecting the eye pupil 501 and the outer wall 4020, there is an area blocked by the frame 1004 where the subject cannot be visually recognized.

[0021] Therefore, in this embodiment, with the following structure, the area blocked by the frame 104 where the subject cannot be visually recognized is reduced.

[0022] Figure 5(a) shows a horizontal cross-sectional view of the display optical system 103 and frame 104 of an AR device 100 according to an embodiment of the present invention. Here, the distance from the pupil 501 to the user side of the frame 104 is denoted as di on the inner wall side and do on the outer wall side. Furthermore, the distance from the pupil 501 to the subject side of the frame 104 is denoted as Di on the inner wall side and Do on the outer wall side. In this embodiment, the tangent to the inner wall 401 has an angle that approaches the optical axis of the display optical system 103 from the subject side to the user side. This angle is along the inner angle β of the frame and is approximately the same as the field of view angle α. That is, the edge of the inner wall 401 at a distance di in the optical axis direction from the pupil 501 is at a distance of di × tan(β) from the optical axis, and the edge of the inner wall 401 at a distance Di in the optical axis direction from the pupil 501 is at a distance of Di × tan(β) from the optical axis. This makes it possible to widen the frame 104 without reducing the field of view, thereby reducing discomfort during observation and increasing the strength of the frame 104. In this embodiment, the tangent to the outer wall 402 has an outer frame angle γ, which is the angle at which it approaches the optical axis of the display optical system 103 from the subject side to the user side. That is, the edge of the outer wall 402 at a distance of do in the optical axis direction from the pupil 501 is at a distance of do × tan(γ) from the optical axis, and the edge of the outer wall 402 at a distance of Do in the optical axis direction from the pupil 501 is at a distance of Do × tan(γ) from the optical axis. In addition, the tangent to the inner wall 401 and the tangent to the outer wall 402 intersect at the position of the pupil 501 on the optical path 203 (on the optical axis). This makes it possible to widen the frame while reducing the visibility of the boundary with the field of view inside the AR device when the subject is visible in the user's field of view without passing through the AR device.

[0023] As described above, at least a portion of the frame 104 is positioned so that the side on which the first light beam exits the display optical system 103 in a direction parallel to the optical path 203 is closer to the optical path 203 than the side on which the first light beam enters the display optical system 103. Furthermore, at least a portion of the frame 104 has a shape in which the width in the direction perpendicular to the optical path 203 is narrower on the side on which the first light beam exits the display optical system 103 in a direction parallel to the optical path 203 than on the side on which the first light beam enters the display optical system 103.

[0024] This configuration ensures the strength of the frame that holds the optical components and display device, while reducing the discomfort caused by the frame during user observation.

[0025] Generally, the position of the pupil 501 is not fixed relative to the AR device, but is considered to be somewhere within a predetermined range due to eye rotation and displacement when the device is attached. This predetermined range in which optical performance is ensured is generally called the eye box. Figure 5(b) shows a horizontal cross-sectional view of the display optical system 103 and frame 104 of the AR device 100 when only the range e is secured as the eye box. As shown in Figure 5(b), for cases where the eyeball is not on the optical axis of the display optical system 103, it is also possible to set the inner frame angle β and outer frame angle γ as extensions from the edge of the eye box, rather than as extensions from the pupil 501 position on the optical axis of the display optical system 103. That is, the edge of the inner wall 401 at a distance di in the optical axis direction from the edge of the eye box is at a distance of di × tan(β) + e from the optical axis, and the edge of the inner wall 401 at a distance Di in the optical axis direction from the pupil 501 is at a distance of Di × tan(β) + e from the optical axis. Furthermore, the edge of the outer wall 402 at a distance of do in the optical axis direction from the eye box end is at a distance of do × tan(γ) + e from the optical axis, and the edge of the outer wall 402 at a distance of Do in the optical axis direction from the pupil 501 is at a distance of Do × tan(γ) + e from the optical axis. In other words, the inner wall 401 and the outer wall 402 are configured so that their tangents intersect within the eye box of the display optical system 103. This makes it possible to create a frame configuration with a shape that reduces discomfort during observation and improves strength, even when the user's eyeballs are rotated or when misalignment occurs during installation.

[0026] Generally, the frame size is larger than the eye box range, which is the range in which the pupil 501 can be positioned. Therefore, the frame 104 has a wedge-shaped frame configuration that is thinner on the user side and thicker on the subject side. This makes it possible to improve the frame's strength while ensuring visibility without reducing the field of view, and while reducing the visibility of the boundary with the device's inner field of view.

[0027] If the priority is to reduce the discomfort caused by the frame during user observation, it is desirable to adopt this wedge-shaped frame configuration around the entire circumference of frame 104. However, due to reasons such as strength considerations and the arrangement of other internal components, it may not be possible to adopt this wedge-shaped frame configuration around the entire circumference. In such cases, the frame configuration shown in Figure 6 may be used.

[0028] Figure 6 is a schematic diagram showing the field of view of an object image seen through a device consisting of a frame 104 that does not have a wedge-shaped frame configuration at the diagonal portion 1041, according to an embodiment of the present invention. As shown in Figure 6, the portion of frame 104 that has a wedge-shaped frame configuration is narrower in width than frame 1004 in Figure 3. If the entire circumference is configured with a wedge-shaped frame, the width will be narrower in the entire circumference compared to frame 1004 in Figure 3.

[0029] As shown in Figure 6, even if the frame configuration does not have this wedge-shaped frame configuration in the diagonal portion 1041 of the field of view (the wedge-shaped frame configuration is used in the portion excluding the diagonal portion 1041), the diagonal portion is the furthest from the eye in the field of view, so the presence of a frame within the field of view is unlikely to cause discomfort. Furthermore, even within the eye box, the likelihood of the pupil being positioned in the diagonal portion during normal use is low, so the impact is limited.

[0030] Furthermore, as a modification of the embodiment relating to the present invention, a configuration may be used in which a transparent member is fixed to a part of the wedge-shaped frame structure to improve the strength of the frame 104. For example, a frame may be formed of a non-transparent member and a transparent member, in which the transparent member is placed around the narrow part of the wedge-shaped non-transparent member for reinforcement, so that the width of the frame as a whole is substantially uniform. With such a configuration, compared to the case in which a frame with substantially uniform width is formed from the transparent member, the area that is obscured by the frame and cannot be seen can be reduced without significantly reducing the strength.

[0031] However, when the subject is viewed through the transparent material, the optical performance may decrease, resulting in reduced resolution and a blurred appearance. Therefore, instead of placing the transparent material around the entire circumference of the frame, placing it in areas where the resolution is low in the human field of vision and the impact on the image is limited, such as the diagonal section 1041, makes it possible to improve the frame's strength while minimizing the impact on the image.

[0032] While 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 its essence. In the embodiments described above, an example of applying the present invention to an AR device that displays a CG image superimposed on transmitted light from a subject was explained, but the present invention is also applicable to other image display devices. For example, the present invention is also applicable to an image display device that displays an image from a second display device superimposed on an image captured by a camera and displayed on a first display device. Furthermore, the superimposed image is not limited to a CG image, but may be an image captured by a camera, text, etc. In other words, the present invention can be applied to any image display device that superimposes an image on a light beam transmitted through a display optical system and has a frame that holds the display optical system. [Explanation of Symbols]

[0033] 100 AR devices 101 Front Cover 102 Rear cover 103 Display optical system 104 frames 105 Ear hook part 106 Nose pad 201 CG Display Devices 401 Interior wall 402 Exterior Wall 501 Pupil

Claims

1. An image display device that superimposes an image onto a first light beam passing through a display optical system, The display optical system has a frame that holds the display optical system around it in a plane that intersects with the optical axis that guides the first light beam of the display optical system, The aforementioned image display device is wearable by the user, The display optical system is positioned in front of the user's eyes when the image display device is attached. The frame is provided such that, when the image display device is attached, the user's field of view includes an area in which a light beam passing outside the frame that does not pass through the display optical system is visible. The image display device is characterized in that at least a portion of the frame is positioned closer to the optical axis on the side where the first light beam exits the display optical system in a direction parallel to the optical axis than on the side where the first light beam enters the display optical system, and has a narrower width in the direction perpendicular to the optical axis.

2. The image display device according to claim 1, wherein the frame has a rectangular shape in a plane intersecting the optical axis, and the side on which the first light beam in the direction parallel to the optical axis exits the display optical system is positioned closer to the optical axis than the side on which the first light beam enters the display optical system, and the width in the direction perpendicular to the optical axis is narrower around the entire circumference of the rectangular shape.

3. The image display device according to claim 1, wherein the frame has a rectangular shape in a plane intersecting the optical axis, and in the portion of the rectangular shape excluding the diagonal, the side on which the first light beam in the direction parallel to the optical axis exits the display optical system is positioned closer to the optical axis than the side on which the first light beam enters the display optical system, and the width in the direction perpendicular to the optical axis is narrower.

4. The image display device according to any one of claims 1 to 3, wherein the frame is positioned such that the side on which the first light beam exits the display optical system in a direction parallel to the optical axis is closer to the optical axis than the side on which the first light beam enters the display optical system, and in a portion of the frame that is narrower in a direction perpendicular to the optical axis, the tangent to the inner wall of the frame and the tangent to the outer wall of the frame intersect on the optical axis.

5. The image display device according to any one of claims 1 to 3, characterized in that the frame is positioned such that the side on which the first light beam exits the display optical system in a direction parallel to the optical axis is closer to the optical axis than the side on which the first light beam enters the display optical system, and in a portion of the frame that is narrower in a direction perpendicular to the optical axis, the tangent to the inner wall of the frame and the tangent to the outer wall of the frame intersect within the eye box of the display optical system.

6. The frame is held and has display means for displaying an image, The display optical system is characterized in that it has a first incident section into which the first light beam is incident, a second incident section into which the second light beam from the display means is incident, an outgoing section from which the first light beam and the second light beam are emitted, and a half-mirror surface that transmits the first light beam incident from the first incident section and reflects the second light beam incident from the second incident section toward the outgoing section.

7. The image display device according to any one of claims 1 to 6, characterized in that it is an AR device or an MR device.

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