Head-mounted display

Abstract

To provide a head-mounted display with the high display quality.SOLUTION: A head-mounted display 100 according to an embodiment comprises: a reflection member which is arranged on the front side of a user and reflects at least a portion of display light forming a display image in the direction of the user; and beam splitters 122L, 122R which are arranged between the reflection member and the eyes of the user, reflect the display light toward the reflection member and transmit the display light reflected by the reflection member. The transmittance of the beam splitter 122L in a direction heading toward the eyes from a first position Y1 on the upper side relative to the eyes of the user matches the transmittance of the beam splitter 122L in a direction heading toward the eyes from a second position Y2 from the lower side relative to the eyes of the user.SELECTED DRAWING: Figure 4

Description

Technical Field

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[0001] The present disclosure relates to a head-mounted display.

Background Art

[0002] Patent Document 1 discloses a head-mounted display including a display element, a beam splitter, and a combiner. The beam splitter and the combiner are half mirrors to form a virtual image in front of the user. The combiner is a concave mirror disposed in front of the beam splitter.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The incident angle of light with respect to the beam splitter changes according to the position of the beam splitter. Therefore, there is a possibility that a luminance difference appears in the display image in the vertical direction. This point will be described using FIG. 10. FIG. 10 is a diagram schematically showing the optical system of the head-mounted display.

[0005] The display element unit 101 is disposed above the beam splitter 122. The beam splitter 122 reflects the display light P11 from the display element unit 101 forward. The display light P11 reflected by the beam splitter 122 enters the combiner 121. The combiner 121 reflects the display light P11 backward. The display light reflected backward by the combiner 121 is defined as display light P12. The display light P12 passes through the beam splitter 122 and enters the user's eye E. Therefore, the user can visually recognize the virtual image I of the display image directly in front.

[0006] The combiner 121 is a concave half-mirror. The combiner 121 transmits ambient light P21 from the front of the combiner 121. The ambient light P21 and the display light P12 pass through the beam splitter 122 and enter the user's eye E. The user can see a superimposed image in which the display image is superimposed on the scenery in front of them.

[0007] The beam splitter 122 is a planar half-mirror. The reflectivity of the beam splitter 122 changes depending on the angle of incidence of light to the plane. Also, the angle of incidence of light to the beam splitter 122 differs depending on the vertical position.

[0008] For example, in the beam splitter 122, the position above eye E is designated as the first position Y1, and the position below eye E is designated as the second position Y2. The angle of incidence of light at the first position Y1 is designated as the angle of incidence θ1, and the angle of incidence of light at the second position Y2 is designated as the angle of incidence θ2. The angles of incidence θ1 and θ2 are the angles formed between the normal to the plane of the beam splitter 122 and the direction of propagation of light toward eye E.

[0009] The incident angle θ1 is smaller than the incident angle θ2. Therefore, the transmittance at the first position Y1 is greater than the transmittance at the second position Y2. Consequently, the upper part of the virtual image I seen by the user becomes brighter, and the lower part becomes darker. Because a difference in brightness occurs between the upper and lower parts of the virtual image I, there is a risk that the display quality will deteriorate.

[0010] This disclosure is made in view of the above points and aims to provide a head-mounted display with high display quality. [Means for solving the problem]

[0011] The head-mounted display according to this embodiment includes a reflective member positioned in front of the user and reflecting at least a portion of the display light that forms the display image toward the user, and a beam splitter positioned between the reflective member and the user's eye and reflecting the display light toward the reflective member and transmitting the display light reflected by the reflective member, wherein the transmittance of the beam splitter in the direction toward the eye from a first position above the user's eye is the same as the transmittance of the beam splitter in the direction toward the eye from a second position below the user's eye. [Effects of the Invention]

[0012] According to this disclosure, it is possible to provide a head-mounted display with high display quality. [Brief explanation of the drawing]

[0013] [Figure 1] This figure shows a partial configuration of the head-mounted display according to this embodiment. [Figure 2] This figure shows the functional block of the head-mounted display according to this embodiment. [Figure 3] This is a diagram illustrating the optical system of a head-mounted display. [Figure 4] This is a schematic diagram showing the configuration of a beam splitter for a head-mounted display according to Embodiment 1. [Figure 5] This graph illustrates the transmittance of the beam splitter at the first and second positions. [Figure 6] This figure shows the configuration of the optical system of the head-mounted display according to Embodiment 2. [Figure 7] This is a schematic diagram showing the configuration of a beam splitter for a head-mounted display according to Embodiment 2. [Figure 8] This is a schematic diagram showing the configuration of a beam splitter for a head-mounted display according to Embodiment 3. [Figure 9]It is a schematic diagram showing the configuration of a beam splitter of a head-mounted display according to Embodiment 4. [Figure 10] It is a diagram for explaining the incident angle according to the incident position of the beam splitter.

Embodiments for Carrying out the Invention

[0014] Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings. However, the present disclosure is not limited to the following embodiments. Also, for clarity of explanation, the following description and drawings are simplified as appropriate.

[0015] Embodiment 1 The head-mounted display according to this embodiment and its display method will be described with reference to the drawings. FIG. 1 is a perspective view schematically showing a partial configuration of the head-mounted display 100. FIG. 2 is a diagram showing a partial functional block of the head-mounted display 100. In FIGS. 1 and 2, mainly, the configuration related to the image display of the head-mounted display 100 is shown. In FIG. 1, the internal configuration of the head-mounted display 100 is shown, and actually, each component shown in FIG. 1 may be covered with a cover or the like.

[0016] The head-mounted display 100 can be applied to various uses such as for games, entertainment, industry, medical, flight simulators, etc. The head-mounted display 100 is, for example, a VR (Virtual Reality) head-mounted display, an AR (Augmented Reality) head-mounted display, or an MR (Mixed Reality) head-mounted display. In this embodiment, the head-mounted display 100 is an optical see-through type head-mounted display used for AR or MR, but a non-transmissive type head-mounted display may also be used.

[0017] Hereinafter, for the sake of clarity of explanation, the explanation will be given using the XYZ three-dimensional orthogonal coordinate system. Based on the user, the front-back direction (depth direction) is the Z direction, the left-right direction (horizontal direction) is the X direction, and the up-down direction (vertical direction) is the Y direction. The front direction is the +Z direction, the back direction is the -Z direction, the right direction is the +X direction, the left direction is the -X direction, the up direction is the +Y direction, and the down direction is the -Y direction.

[0018] A user (not shown) is wearing the head-mounted display 100. The head-mounted display 100 includes a display element unit 101, a frame 102, a left-eye optical system 103L, a right-eye optical system 103R, and a control unit 105. The control unit 105 includes a control unit 105L and a control unit 105R.

[0019] The frame 102 has a goggle shape or a glasses shape and is worn on the user's head by a headband (not shown) or the like. The display element unit 101, the left-eye optical system 103L, the right-eye optical system 103R, the control unit 105L, and the control unit 105R are attached to the frame 102. In FIG. 1, a binocular head-mounted display 100 is shown, but a non-immersive head-mounted display having a glasses shape may also be used.

[0020] The display element unit 101 includes a left-eye display element 101L and a right-eye display element 101R. The left-eye display element 101L generates a display image for the left eye. The right-eye display element 101R generates a display image for the right eye. The left-eye display element 101L and the right-eye display element 101R each include a flat panel display element such as a liquid crystal element or an organic EL (Electro-Luminescence) element. The left-eye display element 101L and the right-eye display element 101R may be displays having a curved surface shape. The left-eye display element 101L and the right-eye display element 101R each include a plurality of pixels arranged in an array. Here, the array arrangement may be not only a two-dimensional arrangement but also a pentile arrangement or the like. The left-eye display element 101L is arranged on the left side (-X side) of the right-eye display element 101R.

[0021] A control unit 105 is provided above (+Y side of) the display element unit 101. The control unit 105 is supplied with video signals, control signals, and power from an external source. For example, video signals, etc., are input to the control unit 105 via a wired connection such as HDMI®, or a wireless connection such as Wi-Fi® or Bluetooth®. The head-mounted display 100 may also include a video generation unit (not shown) that generates video signals, and the video signals, etc., generated by the video generation unit may be input to the control unit 105.

[0022] The control units 105L and 105R are equipped with hardware resources such as a CPU (Central Processing Unit) and memory, and operate according to computer programs stored in memory. Furthermore, each control unit 105L and 105R is equipped with a display drive circuit, etc. The control unit 105L generates a display signal for the left eye image based on video signals, control signals, etc., and outputs it to the left eye display element 101L. As a result, the left eye display element 101L outputs display light for displaying the left eye image. The control unit 105R generates a display signal for the right eye image based on video signals, control signals, etc., and outputs it to the right eye display element 101R. As a result, the right eye display element 101R outputs display light for displaying the right eye image. In other words, the control unit 105 outputs a display signal to the display element unit 101.

[0023] Furthermore, the display element unit 101 is not limited to a configuration in which the left eye display element 101L and the right eye display element 101R are separate display elements; it may also be configured as a single display element. A single display element may generate both the display image for the left eye and the display image for the right eye. In this case, the display element unit 101 generates the left eye image using a portion of one side of the display area of ​​the display, and generates the right eye image using a portion of the opposite side.

[0024] The display element unit 101, the control unit 105, etc., are not limited to being fixed to the frame 102, but may be detachably attached to the frame 102. For example, the display element unit 101, the control unit 105, etc., may be realized by attaching a smartphone or tablet computer, etc., to the frame 102. In this case, an application program (app) that generates display images for the head-mounted display should be pre-installed on the smartphone, etc.

[0025] The left-eye optical system 103L guides the display light output by the left-eye display element 101L as a left-eye image to the user's left eye EL. The right-eye optical system 103R guides the display light output by the right-eye display element 101R as a right-eye image to the user's right eye ER. The left-eye optical system 103L is located to the left (-X side) of the right-eye optical system 103R. The left-eye optical system 103L is located in front of the user's left eye EL (+Z direction). The right-eye optical system 103R is located in front of the user's right eye ER (+Z direction). The user can view the virtual image of the display image generated by the display element unit 101 directly in front of them (+Z direction).

[0026] As described above, the head-mounted display 100 according to this embodiment can be either a semi-transparent or opaque head-mounted display. Here, however, the head-mounted display 100 will be described as a semi-transparent head-mounted display. Accordingly, the left-eye optical system 103L and the right-eye optical system 103R are equipped with a combiner, which will be described later. In the semi-transparent head-mounted display 100, the display light from the display element unit 101 and ambient light are incident on the left eye EL and the right eye ER. Therefore, the user can view a superimposed image in which the displayed image is superimposed on the scenery in front (+Z direction).

[0027] The following describes examples of the left-eye optical system 103L and the right-eye optical system 103R (hereinafter collectively referred to simply as the optical system). Figure 3 is a schematic side view of the optical system. Since the left-eye optical system 103L and the right-eye optical system 103R have the same configuration, only the left-eye optical system 103L will be described in Figure 3.

[0028] The left eye optical system 103L includes a combiner 121L and a beam splitter 122L. The combiner 121L and beam splitter 122L are fixed to the frame 102 shown in Figure 1.

[0029] The combiner 121L is a concave mirror, and the beam splitter 122L is a plane mirror. Both the combiner 121L and the beam splitter 122L are beam splitters such as half-mirrors, reflecting a portion of the incident light and transmitting a portion. If the ratio of reflection to transmission of the combiner 121L is equal, the combiner 121L transmits approximately half of the incident light and reflects the other half. Similarly, if the ratio of reflection to transmission of the beam splitter 122L is equal, the beam splitter 122L transmits approximately half of the incident light and reflects the other half. The combiner 121L and the beam splitter 122L may increase the ratio of reflection and decrease the ratio of transmission, or decrease the ratio of reflection and increase the ratio of transmission.

[0030] The combiner 121L and the beam splitter 122L are positioned directly in front of the user's left eye EL (+Z direction). The combiner 121L is also positioned in front of the beam splitter 122L (+Z direction).

[0031] The left eye display element 101L is positioned above the beam splitter 122L (+Y direction). The left eye display element 101L emits display light PL11 for forming the display image. In other words, the left eye display element 101L is positioned diagonally above and in front of the left eye EL.

[0032] The display light PL11 from the left eye display element 101L will now be described. The display surface of the left eye display element 101L faces downward (-Y direction). Therefore, the display light PL11 from the left eye display element 101L is emitted downward (-Y direction). Below the left eye display element 101L (-Y direction), a beam splitter 122L is positioned at an angle. The display light PL11 from the left eye display element 101L enters the beam splitter 122L. The beam splitter 122L reflects a portion of the display light PL11.

[0033] Furthermore, a light-shielding section may be provided on the lower side of the beam splitter 122L. The light-shielding section blocks the remaining display light PL11 that has passed through the beam splitter 122L. This allows the beam splitter 122 L Because it can block the display light that has passed through it, it is possible to prevent the area below the beam splitter 122L from becoming brighter.

[0034] The beam splitter 122L reflects the display light PL11 from the left eye display element 101L forward (+Z direction). The display light PL11 then enters the combiner 121L. The combiner 121L reflects a portion of the display light PL11 backward (-Z direction). The display light PL11 reflected by the combiner 121L becomes the display light PL12. Furthermore, the combiner 121L is a concave mirror and reflects the display light PL11 so as to focus the display light PL12 toward the left eye EL. The display light PL12 reflected by the combiner 121L enters the beam splitter 122L. The beam splitter 122L transmits a portion of the display light PL12.

[0035] The display light PL12, transmitted through the beam splitter 122L, enters the left eye EL. In this way, the left eye optical system 103L guides the display light PL11 from the left eye display element 101L to the user's left eye EL. This optical system allows a virtual image I to be displayed in front of the user (+Z direction). Furthermore, because a concave mirror is used as the combiner 121L, the displayed image is magnified.

[0036] Next, we will describe the ambient light PL21 coming from the front of the user (+Z direction). A portion of the ambient light PL21 passes through the combiner 121L. The ambient light PL21 that has passed through the combiner 121L is incident on the beam splitter 122L. The beam splitter 122L passes a portion of the ambient light PL21. The ambient light PL21 that has passed through the beam splitter 122L is incident on the left eye EL.

[0037] Since the head-mounted display 100 is semi-transmissive, the combiner 121L combines ambient light PL21 from the front (+Z direction) with display light PL11 from the left-eye display element 101L. The right-eye optical system 103R is the same as the left-eye optical system 103L. The combiner 121R combines ambient light PR21 from the front (+Z direction) with display light PR11 from the right-eye display element 101R. By placing combiners 121L and 121R in front of the user (+Z direction), the head-mounted display 100 can be made into an optical see-through type. The displayed image is superimposed on the scenery in front of the user (+Z direction). In other words, the user can see the scenery with the displayed image superimposed.

[0038] The beam splitter 122L is tilted from the Z direction. That is, the surface of the beam splitter 122 is tilted from the XY plane. Depending on the vertical position (Y position) of the beam splitter 122L, the display light P L The incidence angle of 12 changes. Note that in Figure 3, the tilt angle of the beam splitter 122L with respect to the Z direction is 45°.

[0039] For example, in the beam splitter 122L, the position above the left eye EL is defined as the first position Y1, and the position below the left eye EL is defined as the second position Y2. The angle of incidence of light at the first position Y1 is defined as the angle of incidence θ1, and the angle of incidence of light at the second position Y2 is defined as the angle of incidence θ2. The angles of incidence θ1 and θ2 are the angles between the normal to the plane of the beam splitter 122 and the direction of light propagation. Here, the light defining the angles of incidence θ1 and θ2 can be either the indicator light PL12 reflected by the combiner 121L and directed toward the left eye EL, or the external light PL21 transmitted through the combiner 121L and directed toward the left eye EL.

[0040] As shown in Figure 3, the beam splitter 122L is tilted so that the lower side (-Y side) is closer to the front (+Z side). Therefore, the incident angle θ1 is smaller than the incident angle θ2. For example, the transmittance of the beam splitter 122L increases as the incident angle decreases. Therefore, the upper side of the beam splitter 122L becomes brighter and the lower side becomes darker, which may cause a difference in brightness in the virtual image I.

[0041] Therefore, in this embodiment, the spatial distribution of the transmittance of the beam splitter 122L is adjusted in order to reduce the brightness difference of the virtual image caused by the difference in the angle of incidence. The detailed configuration of the beam splitter 122L will be described below with reference to Figure 4. This is a schematic side cross-sectional view showing the configuration of the beam splitter 122L.

[0042] The beam splitter 122L comprises a substrate 1221 and a half-mirror film 1222. The substrate 1221 is a transparent substrate that transmits light. For example, the substrate 1221 may be a glass substrate or a resin substrate. The half-mirror film 1222 is a thin film formed on the surface of the substrate 1221 that faces the combiner 121L. The half-mirror film 1222 transmits a portion of the incident light. The light transmittance of the half-mirror film 1222 changes depending on its thickness. The thicker the film, the lower the transmittance of the half-mirror film 1222. For example, there is an inverse relationship between film thickness and transmittance.

[0043] As shown in Figure 4, the thickness of the half-mirror film 1222 decreases towards the lower side (-Y side). In the Z direction, the thickness of the half-mirror film 1222 decreases as it moves away from the left eye EL. This reduces the brightness difference of the virtual image caused by the difference in the angle of incidence, thereby improving the display quality of the head-mounted display 100.

[0044] Specifically, the film thickness at the first position Y1 is thicker than the film thickness at the second position Y2. The transmittance of the beam splitter 122L in the direction from the first position Y1 toward the left eye EL is the same as the transmittance of the beam splitter 122L in the direction from the second position Y2 toward the left eye EL. In other words, when light traveling parallel to the Z direction is incident on the beam splitter 122L, the transmittance at the first position Y1 is lower than the transmittance at the second position Y2.

[0045] Thus, the beam splitter 122L has a half-mirror film 1222 whose transmittance changes according to its thickness. And the thickness of the half-mirror film 1222 increases from the top to the bottom. therefore ...and gradually becomes thinner. In this way, the transmittance of the beam splitter 122L in the direction from the first position Y1 toward the left eye EL becomes equal to the transmittance of the beam splitter 122L in the direction from the second position Y2 toward the left eye EL. Therefore, the brightness difference of the virtual image in the vertical direction can be reduced. The display quality of the head-mounted display 100 can be improved.

[0046] For example, a vapor-deposited film can be used as the half-mirror film 1222. The half-mirror film 1222 is a wedge coat that is obliquely vapor-deposited on the substrate 1221 so that the film thickness varies within the plane of the substrate 1221. The half-mirror film 1222 can be deposited on the substrate 1221 with the substrate 1221 tilted relative to the vapor deposition source. In other words, by positioning the substrate 1221 at an angle to the vapor deposition source, the distance from the vapor deposition source to one end of the substrate 1221 becomes greater than the distance from the vapor deposition source to the other end of the substrate 1221. This makes it possible to form a vapor-deposited film such that the film thickness of the half-mirror film 1222 gradually increases from one end of the substrate 1221 to the other end. In Figure 4, the thickness of the half-mirror film 1222 changes continuously, but the thickness of the half-mirror film 1222 may change in steps. For example, the half-mirror film 1222 can be formed with two or more different film thicknesses. The half-mirror film 1222 may be a single layer film or a multilayer film.

[0047] Figure 5 is a graph showing the light transmittance characteristics at a first position Y1 and a second position Y2. In Figure 5, the horizontal axis represents the wavelength of light, and the vertical axis represents the transmittance. Figure 5 shows the transmittance when the incident angle is 40°, 45°, and 50°. Let T1 be the transmittance at the first position Y1, and T2 be the transmittance at the second position Y2. For example, the transmittance T1 when the incident angle θ1 is 40° is shown as T1(40°).

[0048] As shown in Figure 5, the beam splitter 122L has a transmittance distribution such that T1 (40°) and T2 (50°) coincide. Specifically, in Figure 4, the indicator light PL12 at the first position Y1 is tilted -5° with respect to the Z axis, and the indicator light PL12 at the second position Y2 is tilted +5° with respect to the Z axis. In such a case, the thickness distribution of the half-mirror film 1222 is adjusted so that the beam splitter 122L has a transmittance distribution such that T1 (40°) and T2 (50°) coincide. At the first position Y1, the transmittance of light traveling in the direction tilted -5° from the Z direction is the same as the transmittance of light traveling in the direction tilted +5° from the Z direction at the second position Y2.

[0049] In other words, the half-mirror film 1222 has a film thickness distribution such that, at the same incident angle, T1 is lower than T2. ​​For example, T1 (45°) is smaller than T2 (45°). By doing so, the difference in brightness in the vertical direction can be reduced, thereby improving display quality.

[0050] Embodiment 2 In Embodiment 2, the configuration of the beam splitters 122L and 122R differs from that of Embodiment 1. Figure 6 shows ,light This is a schematic diagram showing the academic system. Figure 7 is a schematic side cross-sectional view showing the configuration of beam splitter 122L. The configuration other than beam splitters 122L and 122R is the same as in Embodiment 1, so the explanation is omitted. Also, since beam splitter 122R is the same as beam splitter 122L, the explanation is omitted as appropriate.

[0051] As shown in Figure 6, the beam splitter 122L is divided into a first region S1 and a second region S2. The first region S1 is the region containing the first position Y1. The second region S2 is the region containing the second position Y2. As shown in Figure 6, the upper half of the beam splitter 122L is the first region S1, and the lower half is the second region S2. The second region S2 is located in front of the first region S1.

[0052] As shown in Figure 7, the beam splitter 122L is divided into a first region S1 and a second region S2. Specifically, the beam splitter 122L in the first region S1 is designated as the upper beam splitter 1224, and the beam splitter 122L in the second region S2 is designated as the lower beam splitter 1225. Ta Therefore, the beam splitter 122L is equipped with an upper beam splitter 1224 and a lower beam splitter 1225.

[0053] The upper beam splitter 1224 comprises a substrate 1221a and a half-mirror film 1222a. The lower beam splitter 1225 comprises a substrate 1221b and a half-mirror film 1222b. Substrates 1221a and 1221b are transparent substrates or the like and have the same thickness.

[0054] The half-mirror films 1222a and 1222b are formed on the combiner 121L side of the substrates 1221a and 1221b. The half-mirror films 1222a and 1222b are thin films whose light transmittance changes depending on the film thickness. The thicker the film, the lower the transmittance of the half-mirror film 1222. For example, there is an inverse relationship between film thickness and transmittance. The half-mirror films 1222a and 1222b are thin films formed from the same material. The half-mirror films 1222a and 1222b may be single-layer films or multilayer films.

[0055] The half-mirror films 1222a and 1222b have different thicknesses. Half-mirror film 1222a is formed to be thicker than half-mirror film 1222b. For example, the upper beam splitter 1224 is formed by forming a thin film that will become half-mirror film 1222a on substrate 1221a. The lower beam splitter 1225 is formed by forming a thin film that will become half-mirror film 1222b on substrate 1221b.

[0056] In this way, the transmittance of the upper beam splitter 1224 in the direction from the first position Y1 toward the left eye EL matches the transmittance of the lower beam splitter 1225 in the direction from the second position Y2 toward the left eye EL. Therefore, the brightness difference of the virtual image I in the vertical direction can be suppressed. The display quality of the head-mounted display 100 can be improved. Furthermore, the dividing line between the upper beam splitter 1224 and the lower beam splitter 1225 is near the left eye EL and is therefore blurred and not visible. Thus, the user is less affected by the degradation of display quality due to the dividing line.

[0057] Embodiment 3 The configuration of the head-mounted display according to Embodiment 3 will be explained with reference to Figure 8. Figure 8 is a schematic front view showing the configuration of the beam splitter 122L of the head-mounted display. Note that the configuration other than beam splitters 122L and 122R is the same as in Embodiments 1 and 2, so the explanation will be omitted. Also, beam splitter 122R is beam splitter 122 L Since it is similar to the previous example, the explanation will be omitted.

[0058] In Embodiment 3, the beam splitter 122L is, for example, a polka-dot beam splitter. Specifically, the beam splitter 122L comprises a substrate 1221 and a reflective film pattern 1228. The substrate 1221 is a transparent substrate. A fine reflective film pattern 1228 is formed on the substrate 1221. The reflective film pattern 1228 is formed by coating the substrate 1221 with a metal film such as aluminum.

[0059] Therefore, light incident on areas where the reflective film pattern 1228 is formed is reflected by the beam splitter 122L. Light incident on areas where the pattern 1228 is not formed is transmitted through the beam splitter 122L. In areas where the pattern 1228 is not formed, light is transmitted through the transparent substrate 1221. The reflectivity can be adjusted by adjusting the area occupancy rate of the pattern 1228, i.e., the aperture ratio. The area occupancy rate is the proportion of the reflective film pattern 1228 that is occupied per unit area. By increasing the proportion occupied by the pattern 1228, the transmittance can be lowered. By decreasing the proportion occupied by the pattern 1228, the transmittance can be increased.

[0060] The reflective film pattern 1228 is located near the left eye EL and is too small for the user to see. Pattern 1228 is a fine pattern that is not visible to the naked eye. Therefore, the user does not see pattern 1228 in the virtual image. Pattern 1228 contains multiple circular dots. In other words, the reflective film pattern 1228 is formed as a pattern of multiple dots. Pattern 1228 may have a shape other than circular. The reflective film pattern 1228 may be a single layer or a multilayer film.

[0061] The first region S1, which includes the first position Y1, is located above the user's left eye. The second region S2, which includes the second position Y2, is located below the user's left eye. The area occupancy rate of pattern 1228 differs between the first region S1 and the second region S2.

[0062] Specifically, the area occupancy rate of pattern 1228 in the first region S1 is greater than the area occupancy rate of pattern 1228 in the second region S2. In this way, when the angle of incidence is the same, the transmittance of the first region S1 can be made smaller than the transmittance of the second region S2. In other words, when the angle of incidence is the same, the first region S1 reflects more light than the second region S2. The transmittance of the beam splitter 122L in the direction from the first position Y1 toward the left eye EL matches the transmittance of the beam splitter 122L in the direction from the second position Y2 toward the left eye EL. Since the brightness difference in the vertical direction can be reduced, the display quality of the head-mounted display 100 can be improved.

[0063] In Figure 8, pattern 1228 in the first region S1 is larger in size than pattern 1228 in the second region S2. In other words, the dot size of pattern 1228 in the first region S1 is larger than the dot size of pattern 1228 in the second region S2. The pitch of pattern 1228 is the same in the first region S1 and the second region S2. This allows the transmittance in the direction toward the left eye EL to be matched at each location.

[0064] Of course, the pattern 1228 in the first region S1 and the pattern 1228 in the second region S2 may be the same size. In this case, the pattern 1228 in the first region S1 and the pattern 1228 in the second region S2 are formed with different pitches. In other words, by changing at least one of the following: size, pitch, shape, number, etc., the area occupancy can be changed. By providing an in-plane distribution in the pattern 1228, the transmittance at each position can be made to match. This can suppress brightness unevenness in the vertical direction, thereby improving display quality. Furthermore, the regions with different transmittances in the beam splitter 122L may be further subdivided so that the transmittance in the direction from a point in each region toward the left eye EL matches.

[0065] Embodiment 4 The head-mounted display 100 according to Embodiment 4 will be described with reference to Figure 9. Figure 9 is a schematic side view showing the configuration of the beam splitter 122L of the head-mounted display 100. Note that the configuration other than the beam splitter 122L is the same as in Embodiments 1 to 3, so its description will be omitted. For example, the beam splitter 122L is shown in Figure 9 As shown, it is divided into a first region S1 and a second region S2. The first region S1 is the region that includes a first position Y1 which is above the left eye, and the second region S2 is the region that includes a second position Y2 which is below the left eye EL.

[0066] The beam splitter 122L comprises a substrate 1221, a half-mirror film 1222, and an absorption filter 1229. The half-mirror film 1222 is formed on the side of the substrate 1221 facing the combiner 121L. The absorption filter 1229 is formed on the side of the substrate 1221 facing the left eye EL. In other words, the components are arranged from rear to front in the order of absorption filter 1229, substrate 1221, and half-mirror film 1222. The absorption filter 1229 absorbs a portion of the light and transmits the rest.

[0067] The half-mirror film 1222 is formed with a uniform thickness across the entire plane. Therefore, the reflectance and transmittance of the half-mirror film 1222 are uniform across the plane. On the other hand, the absorption rate of the absorbance filter 1229 is not uniform across the plane. The absorption rate of the absorbance filter 1229 differs between the first region S1 and the second region S2. The absorption rate of the absorbance filter 1229 in the first region S1 is higher than that of the absorbance filter 1229 in the second region S2.

[0068] Therefore, the transmittance of the beam splitter 122L in the direction from the first position Y1 toward the left eye EL matches the transmittance of the beam splitter 122L in the direction from the second position Y2 toward the left eye EL. This reduces the brightness difference in the vertical direction. By attaching such an absorbance filter 1229 to the substrate 1221, the display quality can be improved.

[0069] The absorption rate of the light-absorbing filter 1229 can be adjusted by the concentration of the light-absorbing material contained in the transparent material. For example, the higher the concentration of the light-absorbing material, the higher the absorption rate. In the first region S1, the concentration of the light-absorbing material is high, and in the second region S2, the concentration of the light-absorbing material is low. In this way, by making the concentration of the light-absorbing material in the first region S1 higher than that in the second region S2, the brightness uniformity in the vertical direction can be improved. The light-absorbing filter 1229 in the first region S1 and the light-absorbing filter 1229 in the second region S2 may be formed integrally or as separate components.

[0070] Although the head-mounted display 100 has been described as an optical see-through type head-mounted display, the head-mounted display 100 may also be an opaque type head-mounted display. In the case of an opaque type head-mounted display, a reflective mirror may be provided instead of the combiners 121L and 121R. In other words, the reflective member positioned in front of the beam splitter 122 may be a beam splitter such as a half-mirror, or it may be a reflective mirror. The reflective member reflects the display light towards the user.

[0071] The present inventors have described the invention in detail based on embodiments above, but it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways without departing from its essence. It is also possible to combine two or more of the above embodiments as appropriate. [Explanation of Symbols]

[0072] EL left eye ER right eye 100 Head-Mounted Displays 101 Display element 101L Display element for left eye 101R Display element for right eye 102 frames 103L Optical system for left eye 103R Optical system for right eye 121L, 121R, 121 Combiner 122L, 122R, 122 Beam Splitter PL11, PL12 display light PL21 Outdoor Light 1221 circuit board 1222 Half-mirror film 1224 Upper Beam Splitter 1225 Lower Beam Splitter 1228 patterns 1229 Absorbance filter S1 First Domain S2 Second area Y1 First position Y2 2nd Pokémon

Claims

1. A reflective member positioned in front of the user and reflecting at least a portion of the display light that forms the display image toward the user, A beam splitter is positioned between the reflective member and the user's eye, reflecting the display light toward the reflective member and transmitting the display light reflected by the reflective member, the beam splitter having a thin film whose transmittance changes with thickness, wherein the upper thickness of the thin film is relatively larger than the lower thickness of the thin film. A head-mounted display in which the transmittance of the beam splitter in the direction toward the eye from a first position above the user's eye matches the transmittance of the beam splitter in the direction toward the eye from a second position below the user's eye.

2. The beam splitter includes a thin film whose transmittance changes depending on its thickness. The head-mounted display according to claim 1, wherein the thickness of the thin film gradually decreases from the top to the bottom.

3. A reflective member positioned in front of the user and reflecting at least a portion of the display light that forms the display image toward the user, A beam splitter is positioned between the reflective member and the user's eye, reflecting the display light toward the reflective member and transmitting the display light reflected by the reflective member, and having a thin film whose transmittance changes according to its thickness, and is divided into a first region including a first position above the user's eye and a second region including a second position below the user's eye. The beam splitter comprises a beam splitter in which the thickness of the thin film in the first region is greater than the thickness of the thin film in the second region, A head-mounted display in which the transmittance of the beam splitter in the direction toward the eye from a first position above the user's eye matches the transmittance of the beam splitter in the direction toward the eye from a second position below the user's eye.

4. A reflective member positioned in front of the user and reflecting at least a portion of the display light that forms the display image toward the user, A beam splitter is positioned between the reflective member and the user's eye, reflecting the display light toward the reflective member and transmitting the display light reflected by the reflective member, wherein a fine pattern of light-reflecting film is formed on the beam splitter. The beam splitter comprises a first region including a first position above the user's eye and a second region including a second position below the user's eye, wherein the area occupancy rate of the reflective film of the fine pattern differs between these two regions. A head-mounted display wherein the transmittance of the beam splitter in the direction toward the eye from the first position matches the transmittance of the beam splitter in the direction toward the eye from the second position.

5. A reflective member positioned in front of the user and reflecting at least a portion of the display light that forms the display image toward the user, A beam splitter is positioned between the reflective member and the user's eye, reflecting the display light toward the reflective member and transmitting the display light reflected by the reflective member, the beam splitter having a light-absorbing filter formed thereon, wherein the absorption rate of the light-absorbing filter differs between a first position including a first position above the user's eye and a second position below the user's eye. A head-mounted display wherein the transmittance of the beam splitter in the direction toward the eye from the first position matches the transmittance of the beam splitter in the direction toward the eye from the second position.

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