Head-mounted display

Abstract

To provide a head-mounted display having a wide viewing angle and a good wearing feeling.SOLUTION: A head-mounted display (1) includes: a display light output portion (61) that outputs display light (Lt8) forming a display image; a reflecting mirror (63) that reflects the display light (Lt8); a half mirror (64) that reflects the display light (Lt8) incident from the reflecting mirror (63) and directs the display light forward; and a concave screen (65) that is disposed in front of the half mirror (64) and on which the display light (Lt8) reflected by the half mirror (64) is projected and the display image is formed. The display light output portion (61) is closer to a rear side of the half mirror (64).SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a head-mounted display. [Background technology]

[0002] In recent years, head-mounted displays have been able to provide effects that exceed those obtained with a user's actual vision in terms of the sense of immersion in virtual reality, etc. Such head-mounted displays are shown in, for example, Patent Document 1. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-92746 Summary of the Invention [Problem to be solved by the invention]

[0004] Generally, a head-mounted display is an image display device that allows a user to view a magnified virtual image by using a group of precision optical components to focus display light generated very close to the user's eyes to create a large virtual screen in the distance. Head-mounted displays are classified into closed-type head-mounted displays, which allow the user to see only the display light output from a display light output unit, but not the surrounding environment, and transmissive head-mounted displays, which allow the user to see both the surrounding environment and the display light output from the display light output unit through a concave screen. Conventional transmissive head-mounted displays, such as those described in Patent Document 1, generally include a liquid crystal display (LCD), a half mirror, and a screen. In the following description, the up, down, left, right, front, and rear directions are defined as the up, down, left, right, front, and rear directions of a user wearing a head-mounted display in a standing position. The LCD display is positioned above and in front of the user wearing the head-mounted display, and the display light from the LCD display is reflected forward by a half mirror installed in front of the user's eyes. The display light reflected by the half mirror is then reflected backward by a concave screen installed in front of the half mirror. The display light reflected by the concave screen is superimposed on the external light that has passed through the concave screen, passes through the half mirror, and enters the user's eyes together with the external light.

[0005] It is desirable for such head-mounted displays to have as wide a viewing angle as possible in order to obtain a greater amount of visual information and a higher sense of realism.

[0006] In conventional transmissive head-mounted displays, the liquid crystal display is positioned above and in front of the user's eyes. Therefore, if the viewing angle of the displayed image in the vertical direction is to be widened, not only the liquid crystal display and concave screen but also the tilted half mirror must be enlarged, resulting in a large forward protrusion. In other words, if the concave screen is made longer vertically, the front-to-back length of the liquid crystal display must be increased, and the vertical and front-to-back widths of the half mirror, which is tilted so that it intersects the visual axis (the axis along which light passes when the line of sight is directed toward an object) at an angle of, for example, 45 degrees, must also be increased. This not only increases the mass of the head-mounted display compared to conventional displays, but also moves the center of gravity further forward from the user's head, increasing the feeling of pressure from the contact area that comes into contact with the face, potentially making it less comfortable to wear for long periods of time.

[0007] An object of the present invention is to provide a head-mounted display that has a wide viewing angle and is comfortable to wear. [Means for solving the problem]

[0008] In order to solve the above-mentioned problems, one embodiment of the head-mounted display of the present invention comprises a display light output unit that outputs display light that forms a display image, a reflective mirror that reflects the display light, a half mirror that reflects the display light incident from the reflective mirror and directs it forward, and a concave screen that is arranged in front of the half mirror and onto which the display light reflected by the half mirror is projected to form the display image, and is characterized in that the display light output unit is located behind the half mirror. [Effects of the Invention]

[0009] The head mounted display of the present invention has the advantages of a wide viewing angle and a comfortable fit. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a perspective view showing a state in which a user 2 wears a head-mounted display 1 according to an embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view of FIG. 1 in which the outer cover 3 and the attachment belt 4 are not shown. [Figure 3] FIG. 3 is a perspective view showing the optical system of the head mounted display 1 in a worn state. [Figure 4] FIG. 4 is a front view of FIG. [Figure 5] FIG. 5 is a schematic right side view showing the optical path of the head mounted display 1. As shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0011] The present embodiment will be described below with reference to the drawings. In the drawings, identical or similar parts are designated by identical or similar reference numerals. However, it should be noted that the drawings are schematic and may differ from the actual product. Furthermore, the embodiments shown below are intended to exemplify devices and methods for embodying technical ideas, and do not specify the material, shape, structure, arrangement, etc. of each component. Various modifications can be made to the present embodiment within the scope of the claims.

[0012] FIG. 1 is a perspective view showing a state in which a user 2 wears a head-mounted display 1 according to an embodiment of the present invention. FIG. 2 is a perspective view of FIG. 1 with an outer cover 3 and a wearing belt 4 not shown. FIG. 3 is a perspective view showing the optical system of the head-mounted display 1 in a worn state. FIG. 4 is a front view of FIG. 2. In the following description, up, down, left, right, front, and rear directions are defined by arrows in FIG. 1. The head-mounted display 1 includes an interpupillary adjustment mechanism 7 (see FIGS. 2 and 4) and optical units PL and PR that are symmetrically configured for the left and right eyes 21 and 22 (see FIG. 3) of the user 2, respectively. Therefore, for ease of description, the left and right optical units PL and PR are denoted by the same reference numerals. In the following description, up, down, left, right, front, and rear directions are defined by arrows in FIG. 1. As described above, these directions are the up, down, left, right, front, and rear directions of the user 2 when the head-mounted display 1 is worn on the head 20 of the user 2 in an upright position.

[0013] As shown in FIG. 1, the head-mounted display 1 is worn on the head 20 of a user 2 using a wearing belt 4. The wearing belt 4 is configured to include side belts 41 that surround the temples 23 of the user 2 and a top belt 42 that is routed around the top 24 of the head. The side belts 41 include pads 411 that come into contact with the back of the head 25 of the user 2, and the top belt 42 includes a pad 421 that comes into contact with the top 24. Most of the mass of the head-mounted display 1 is supported on the top belt 42. The form of the wearing belt 4 is not limited to that shown in FIG. 1 and may be determined appropriately depending on the shape of the head-mounted display 1, etc. In this embodiment, the wearing belt 4 is attached to the outer cover 3 of the head-mounted display 1, and the outer cover 3 and the wearing belt 4 are not shown in FIGS. 2 to 4.

[0014] FIG. 5 is a right side view schematically showing the optical path 8 of the head mounted display 1 of the embodiment. The optical path 8 shown here is an optical axis. The head mounted display 1 has a pair of optical units PL and PR arranged symmetrically on the left and right inside. Each of the optical units PL and PR has an optical component group 6 and an inner cover 5 (see FIGS. 2 and 4), which will be described next. The inner cover 5 covers the optical component group 6 to block light, and holds each optical component in a predetermined position and posture. The outer cover 3 shown in FIG. 1 is attached to cover the inner cover 5 of the optical units PL and PR. A wearing belt 4 is attached to the outer cover 3.

[0015] The head-mounted display 1 has an optical component group 6 that is held in a light-shielded state by the inner cover 5. As shown in FIGS. 3 and 5 , the optical component group 6 includes a display light output unit 61, a magnifying optical system 62, a reflecting mirror 63, a half mirror 64, and a concave screen 65. As shown in FIG. 5 , an optical path 8 of the optical component group 6 includes an optical path 81 between the display light output unit 61 and the magnifying optical system 62, an optical path 82 between the magnifying optical system 62 and the reflecting mirror 63, an optical path 83 between the reflecting mirror 63 and the half mirror 64, an optical path 84 between the half mirror 64 and the concave screen 65, and an optical path 85 between the concave screen 65 and the user's eyes 21 and 22. The head-mounted display 1 includes an optical component group 6 that configures the optical paths 8 for each of the left and right eyes 21 and 22 of the user 2. As shown in FIG. 3 , a pair of optical component groups 6 are arranged symmetrically with respect to the nose 28 of the user 2. 2 and 4 is configured as an assembled rectangular tube, covers the optical component group 6 and the optical path 8 to block light, and holds the optical component group 6 in a predetermined position. The inner cover 5 holds at least the display light output unit 61 and the reflecting mirror 63. The half mirror 64 and the concave screen 65 may be held by a cover separate from the inner cover 5. The magnifying optical system 62 is held by the inner cover 5 when it is placed on the optical path 8 between the display light output unit 61 and the reflecting mirror 63.

[0016] 5, the head mounted display 1 has a display signal generating device 9 together with an optical component group 6. The display signal generating device 9 generates a signal of a display image to be superimposed on external light and visually recognized, and outputs the signal to a display light output unit 61.

[0017] The display light output unit 61 is, for example, a display element such as a liquid crystal display with a diagonal of 3.2 inches (57 mm × 57 mm) on one side (eye). The display light output unit 61 outputs display light Lt8, which is a display image, based on a signal from the display signal generating device 9. The display light Lt8 (optical path 81) output from the display light output unit 61 is magnified by approximately four times by the magnifying optical system 62 (optical path 82), reflected by the reflecting mirror 63, and incident on the half mirror 64 (optical path 83). The half mirror 64 is disposed in front of the eyes 21, 22 of the user 2, and reflects the display light Lt8 (optical path 83) from the reflecting mirror 63 so as to be directed forward (optical path 84) and projected onto the concave screen 65. The concave screen 65 is formed to have a diagonal size of, for example, 5.5 inches (100 mm x 120 mm), and reflects the display light Lt8 (optical path 84) from the half mirror 64 backward (optical path 85), superimposing it on external light Lt1 of the scenery that has entered from the front and passed through, and causes it to enter the eyes 21, 22 of the user 2. This allows the user 2 to view an image in which the display image and the scenery in front are superimposed.

[0018] 5, the half mirror 64 and the concave screen 65 reflect a portion of the display light Lt8 (optical path 83) from the reflecting mirror 63 and transmit a portion of the display light Lt8. If the reflection rate and transmission rate of the half mirror 64 are equal, the half mirror 64 transmits approximately half of the amount of the display light Lt8 (optical path 83) from the reflecting mirror 63 and reflects the remaining half. Similarly, if the reflection rate and transmission rate of the concave screen 65 are equal, the concave screen 65 transmits approximately half of the amount of the external light Lt1 and reflects the remaining half. The half mirror 64 and the concave screen 65 may increase the reflection rate and decrease the transmission rate, or may decrease the reflection rate and increase the transmission rate.

[0019] 5 is a schematic diagram, and as shown in Fig. 3, the display light output unit 61 and the magnifying optical system 62 are arranged so as to extend outward in the left and right directions rather than directly above the forehead 26 of the user 2, with the display light output unit 61 at the farthest position. The reflecting mirror 63 is arranged near the left and right center of the forehead and face 27 of the head 20, and the half mirror 64 is arranged diagonally downward and forward and outward to the left and right from the reflecting mirror 63. Therefore, the half mirror 64 is arranged in front of the eyes of the user 2 at an angle so as to reflect light from the display light output unit 61 and the magnifying optical system 62, which are arranged on the left and right outer sides above the head 20, towards the reflecting mirror 63 diagonally downward and forward and outward to the left and right.

[0020] In the head mounted display 1 configured as described above, a reflecting mirror 63 is interposed between the display light output unit 61 and the half mirror 64 on the optical path 8. Conventionally, when projecting the display light Lt8 from the display light output unit onto a concave screen at the same magnification, the light from the display light output unit 61 needs to be directly incident on the half mirror 64. To simply apply this to FIG. 5 , the display light output unit 61 needs to be disposed as shown by the two-dot chain line so that the light of the optical path 80 incident on the half mirror 64 is perpendicular to the display light output unit 61.

[0021] In contrast, in the head mounted display 1, a reflecting mirror 63 is interposed between the display light output unit 61 and the half mirror 64. This increases the degree of freedom in the arrangement position of the display light output unit 61. In this embodiment, one side of the display light output unit 61 is located behind the half mirror 64. For example, the center position of the surface of the display light output unit 61 that outputs the display light Lt8 is located behind the center position of the half mirror 64.

[0022] Therefore, when the concave screen 65 is made longer in the vertical direction in order to widen the viewing angle W (see FIG. 5) in the vertical direction, the display light output unit 61 can be positioned behind the concave screen 65 rather than directly above it. For example, the display light output unit 61 can be positioned directly above the forehead 26 of the user 2 (so that at least a part of the display light output unit 61 covers the head when viewed from above) rather than above the space in front of the eyes 21, 22 of the user 2.

[0023] The head mounted display 1 is disposed so that the display light output unit 61 is located behind the half mirror 64 when worn by a user in an upright position. Specifically, as shown in Fig. 5 , a first position, which is the center of the surface from which the display light output unit 61 outputs the display light Lt8, is located behind a second position, which is the center of the surface onto which the display light Lt8 reflected by the reflecting mirror 63 of the half mirror 64 is incident. It is also preferable that the first position is located higher than the second position. In other words, it is sufficient that the display light output unit 61 is located behind the half mirror 64, and the positions of the display light output unit 61 and the half mirror 64 are disposed so that the center of gravity of the head mounted display 1 is closer to the rear.

[0024] In this case, with the head mounted display 1 attached to the head 20 using the attachment belt 4, part of the mass of the head mounted display 1 can be applied directly from above to the head 20 of the user 2. This reduces the degree to which the head mounted display 1 will tip forward due to its weight when attached to the head, and reduces the moment applied to the face 27 (see FIG. 3), thereby suppressing the feeling of pressure when worn. As a result, the head mounted display 1 can be worn comfortably for long periods of time even when the viewing angle W in the vertical direction is widened.

[0025] Furthermore, the half mirror 64 of the head mounted display 1 is disposed in a position such that the intersection angle θ, which is the minor angle with the horizontal line, which is a straight line that intersects at a right angle with the up-down (vertical) direction of the head mounted display 1, is larger than 45°, unlike the 45° of the conventional structure. For example, as shown in Fig. 5, when the head mounted display 1 is worn by a user 2 in an upright position, the horizontal line Ea passes through approximately the center 651 of the concave screen 65 in the up-down direction, and the intersection angle θ, which is the minor angle between the horizontal line Ea and the half mirror 64, is larger than 45°, unlike the 45° of the conventional structure. The interposition of the reflecting mirror 63 enables such a free layout, so that the shape, arrangement position, arrangement angle, etc. of the reflecting mirror 63, the half mirror 64, and the concave screen 65 can be freely set.

[0026] In this way, the head mounted display 1 can keep the depth L (see FIG. 5) short even if the concave screen 65 and half mirror 64 are enlarged to widen the viewing angle W in the vertical direction. This makes it possible to keep the center of gravity of the head mounted display 1 as far forward as possible, preventing it from tipping forward when worn and reducing pressure on the face 27. The viewing angle W was previously around 45°, but with the head mounted display 1, it can be expanded beyond 45° to around 60°.

[0027] 3 and 5, the head mounted display 1 is provided with a magnifying optical system 62 between the display light output unit 61 and the reflecting mirror 63. The magnifying optical system 62 is composed of any combination of convex lenses, concave lenses, spherical lenses, aspherical lenses, etc. In the example shown in FIG. 5, the magnifying optical system 62 is composed of, from the display light output unit 61 side, a convex lens 621, a convex lens 622, a concave lens 623, and a convex-concave lens 624. A concave surface 6241 of the convex-concave lens 624 is aspherical. By including the magnifying optical system 62, the head mounted display 1 can suppress distortion of the displayed image and control the angle of view, and by combining the left and right optical systems independently with the interpupillary adjustment mechanism 7, it can realize a clear displayed image with a wide viewing angle.

[0028] 2 and 4 connects the inner covers 5 of the pair of left and right optical units PL and PR, and has the function of moving the optical units PL and PR closer to or farther apart and maintaining (locking) them in an appropriate position using a screw mechanism (not shown). In other words, the user of the head mounted display 1 can manually adjust and lock the distance between the optical units PL and PR so that it matches the distance between their own eyes in the left-right direction.

[0029] In the head mounted display 1, when the concave screen 65 is enlarged to widen the viewing angle W, the magnifying optical system 62 is used, and the brightness and resolution of the display light output unit 61 are increased, so that the same image quality as before the viewing angle W was widened can be maintained. Therefore, the display light output unit 61 can be made smaller than the concave screen 65, and although the provision of the magnifying optical system 62 increases the number of parts and weight, the configuration up to the half mirror 64 can be made smaller, which prevents the forward tilt and reduces the feeling of pressure on the face 27.

[0030] Additionally, in the head mounted display 1, the magnifying optical system 62 may be configured to include a correction lens that corrects the arc shape of the concave screen 65. The correction lens is used to correct and optimize image distortion that occurs because the concave screen 65 is formed in an arc shape obtained by cutting out a part of a sphere, while the display light output unit 61, which is realized by a liquid crystal display or the like, is a flat plate.

[0031] Furthermore, in the head mounted display 1, the display signal generating device 9 may generate a display signal that has been corrected for the curved shape of the concave screen 65 and the distortion of the magnifying optical system 62. The magnifying optical system 62 itself can correct the curved shape of the concave screen 65, magnify the display light, and correct distortion and the like that occurs in the magnifying optical system 62 itself due to the presence of the magnifying optical system 62. However, by correcting and adjusting the display signal itself, for example by increasing the brightness of pixels in the peripheral area, a good display image with less distortion and brightness unevenness can be projected.

[0032] The magnifying optical system 62 is not limited to being provided between the display light output unit 61 and the reflecting mirror 63 on the optical path 8 as in the present embodiment, but may also be provided between the reflecting mirror 63 and the half mirror 64. Furthermore, the magnifying optical system 62 may be functionally divided, with a portion that realizes some of the functions being provided between the display light output unit 61 and the reflecting mirror 63 and a portion that realizes the remaining functions being provided between the reflecting mirror 63 and the half mirror 64. That is, the magnifying optical system 62 may be provided at least either in front of or behind the reflecting mirror 63 on the optical path 8 from the display light output unit 61 to the concave screen 65 for the display light Lt8. Furthermore, for example, a diopter adjustment device, an eyepiece, or the like may be provided as appropriate between the half mirror 64 and the eyes 21, 22 of the user 2. [Explanation of symbols]

[0033] 1. Head-mounted display 2 User 20 heads 21,22 eyes 23 Temporal head 24 Top of the head 25 Back of head 26 Frontal region 27 Face 28 Nose 3 Outer cover 4. Wearing belt 41 Side Belt 411,421 pads 42 Top Belt 5 Inner cover 6 Optical Components 61 Display light output unit 62 Magnifying Optical System 621,622 Convex lens 623 Concave Lens 624 Convex and concave lenses 6241 Concave 63 Reflective mirror 64 Half Mirror 65 Concave Screen 651 Central part 7 Interpupillary adjustment mechanism 8,81,82,83,84,85 Optical path 9 Display signal generation device Ea horizontal line L Depth Lt1 External light Lt8 display light PL, PR optical unit W viewing angle θ intersection angle

Claims

1. a display light output unit that outputs display light that forms a display image; a reflecting mirror that reflects the display light; a half mirror that reflects the display light incident from the reflecting mirror and directs it forward; a concave screen disposed in front of the half mirror, onto which the display light reflected by the half mirror is projected to form the display image; Equipped with The display light output unit is a head-mounted display located behind the half mirror.

2. 2. The head mounted display according to claim 1, wherein a first position, which is the center of the display light output unit, is located higher than a second position, which is the center of the half mirror.

3. 3. The head-mounted display according to claim 1, wherein a minor angle between the half mirror and the horizontal line is greater than 45 degrees.

4. 3. The head-mounted display according to claim 1, further comprising a magnifying optical system for magnifying the display light, at least on one side in front of and on the other side behind the reflecting mirror, in an optical path from the display light output unit to the concave screen.

Images