Head-mounted display, shutter, optical device, and manufacturing method of shutter

Abstract

The present disclosure relates to a head-mounted display, a shutter, an optical device, and a manufacturing method of a shutter. The shutter includes a light-blocking portion made of a light-blocking material. The light-blocking portion is disposed inside a plate-shaped base made of a light-transmitting material. In a plan view of a main surface of the plate-shaped base, the light-blocking portions are arranged at a predetermined interval to sandwich a light-transmitting portion. A width of each light-blocking portion is 9% or less of the predetermined interval between the light-blocking portions.

Description

TECHNICAL FIELD

[0001] The present application relates to a head-mounted display, a louver for an optical device such as a head-mounted display, and a manufacturing method of the louver, and the like. BACKGROUND

[0002] In recent years, head-mounted displays have been used in various fields including virtual reality. The head-mounted display is superior to a direct-view type flat panel display or a projection type projection display because an image can be displayed from an arbitrary direction, or an image can be superimposed and displayed on an external image viewed from the user's position.

[0003] As Figure 9 schematically illustrated in FIG. 1, a head-mounted display includes a display panel 21 that displays an image, and an optical element 22 that forms an image of display light IMG displayed on the display panel 21 in the vicinity of the user's eye 24. Note that, Figure 9 is merely a conceptual diagram, and an optical path changing element such as a mirror or a PBS can be provided between the display panel 21 and the user's eye 24, and the display panel 21 and the optical element 22 can be arranged at different positions. Furthermore, the optical element 22 can be a transmissive optical element such as a convex lens, a reflective optical element such as a concave mirror, or a plurality of combinations thereof.

[0004] Between the user's eye 24 and the optical element 22 or the above-described optical path changing element, an optical path space for securing the optical path length of the display light IMG is required. When external light 25 enters the optical path space from the surroundings, a part of the external light is reflected by the optical element 22 (for example, a lens interface) and superimposed on the display light IMG, and thus reaches the user's eye 24. Because such external light 25 causes degradation of the image quality of the display image due to so-called external light ghosting, it is preferable to prevent the external light from entering the optical path space in the head-mounted display as much as possible.

[0005] Japanese Patent Publication No. 2020-160424 discloses a head-mounted display including a combiner that combines display light of a display image with external light from the front, in which a louver having a light-shielding property is provided below an optical path space of the display light directed to the user's eye by being reflected by the combiner. It is also disclosed that the head-mounted display can be covered with a cover.

[0006] A head-mounted display is provided with circuitry such as a display unit and communication circuitry (i.e., heat generating elements). However, in a case where the entire periphery of an optical path space is surrounded by a light shielding member and a user's face, heat from the heat generating elements and moisture from the user remain in the optical path space. If the optical path space becomes high in temperature and high in humidity, the user can feel uncomfortable for a long time. In addition, an optical element can temporarily fog and degrade image quality, or characteristics of the optical element can degrade.

[0007] Therefore, in a head-mounted display, there is a need for a technology capable of suppressing degradation of display image quality due to external light and capable of suppressing high temperature and high humidity inside the head-mounted display. SUMMARY

[0008] According to a first aspect of the present application, a head-mounted display includes an optical unit configured to direct display light emitted from a display panel to a user's eye, and a louver disposed in an optical path of the display light from the optical unit toward the user's eye. The louver includes light-transmissive portions having a predetermined width and light-shielding portions disposed to sandwich the light-transmissive portions when viewed in a direction of an optical axis of the optical unit.

[0009] According to a second aspect of the present application, the louver includes light-shielding portions made of a light-shielding material. The light-shielding portions are provided inside a plate-shaped base made of a light-transmissive material. In a plan view of a main surface of the plate-shaped base, the light-shielding portions are arranged at a predetermined interval to sandwich the light-transmissive portions. A width of each of the light-shielding portions is 9% or less of the predetermined interval between the light-shielding portions.

[0010] According to a third aspect of the present application, a method for manufacturing a louver includes applying a resin material to a substrate, molding the resin material applied to the substrate into a concave-convex shape having portions provided at a predetermined pitch, curing the resin material after the molding to form a first base, forming light-shielding portions by applying a light-absorbing material or a light-reflecting material along the concave-convex shape of the first base, applying a resin material to the first base on which the light-shielding portions are formed, molding the resin material applied to the first base, and curing the resin material after the molding to form a second base.

[0011] Other features of the present application will become apparent from the following description of exemplary embodiments with reference to the drawings. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1 is a schematic view illustrating a configuration of an optical system of a head-mounted display according to a first embodiment.

[0013] Figure 2 is a schematic view illustrating a configuration of an optical system of a head-mounted display according to a modification of the first embodiment.

[0014] Figure 3A is a schematic cross-sectional view illustrating a cross section cut in a direction perpendicular to the main surface of the shutter according to the first embodiment.

[0015] Figure 3B is an enlarged view in which a portion of the schematic cross-sectional view is enlarged.

[0016] Figure 3C is a plan view of the main surface of the shutter according to the first embodiment.

[0017] Figure 4 is a plan view of the head-mounted display according to the first embodiment viewed from the user side.

[0018] Figure 5A is a view illustrating a state in which a resin material is applied to a substrate in the manufacturing method of the shutter according to the embodiment.

[0019] Figure 5B is a view illustrating an intermediate state in which the resin material is molded on the substrate using a mold.

[0020] Figure 5C is a view illustrating a state in which the resin material is cured by irradiation with ultraviolet rays.

[0021] Figure 5D is a view illustrating a state of demolding.

[0022] Figure 6A is a view illustrating a state in which a material for the light-shielding portion is applied using a dispenser in the manufacturing method of the shutter according to the present embodiment.

[0023] Figure 6B is a view illustrating a state in which a resin material for forming a second base is applied, and then ultraviolet rays are irradiated through a template to cure the resin material.

[0024] Figure 6C is a view illustrating a state of demolding.

[0025] Figure 7A is a schematic cross-sectional view illustrating a cross section cut in a direction perpendicular to the main surface of the shutter according to the second embodiment.

[0026] Figure 7B is a plan view of the main surface of the shutter according to the second embodiment.

[0027] Figure 8A is a plan view of the main surface of the shutter according to the third embodiment.

[0028] Figure 8B is a plan view of the main surface of the shutter according to the fourth embodiment.

[0029] Figure 8C is a plan view of a main surface of a shutter according to the fifth embodiment.

[0030] Figure 8D is a plan view of a main surface of a shutter according to the sixth embodiment.

[0031] Figure 9 is a schematic view illustrating a configuration of an optical system of a conventional head-mounted display. DETAILED DESCRIPTION

[0032] A head-mounted display, a shutter for a head-mounted display, and the like according to an embodiment of the present application will be described with reference to the accompanying drawings.

[0033] In the drawings referred to in the following description of embodiments and examples, elements denoted by the same reference numerals have the same function unless otherwise specified.

[0034] First Embodiment

[0035] Optical System of Head-Mounted Display

[0036] Figure 1 is a schematic view illustrating a configuration of an optical system of a head-mounted display 100 according to the first embodiment. Note that, since the head-mounted display 100 is a head-mounted display for both right and left eyes, the optical system for the right eye and the optical system for the left eye are illustrated. Figure 1 is a schematic view for explaining the arrangement of the optical system, and thus mounting tools to be mounted on the head of the user, a communication unit for transmitting video information, a power supply unit, and the like are omitted.

[0037] Reference numeral 21 denotes a display panel that is a display unit, reference numeral 22 denotes an optical element, reference numeral 23 denotes a shutter, and reference numeral 24 denotes an eye of the user. The head-mounted display 100 is provided with one optical system for each unit of the right eye and the left eye, and a video for the right eye is displayed on the display panel of the right eye unit, and a video for the left eye is displayed on the display panel of the left eye unit. Figure 1 One unit of the optical system for the right eye or the left eye is illustrated. Specifically, the display panel 21 is, for example, an organic EL panel or a liquid crystal panel.

[0038] The optical element 22, serving as the image-forming optical unit, is an optical element that guides the display light IMG emitted from the display panel 21 toward the user's eye, focuses the display light IMG near the user's eye position, and enables the user to recognize the image displayed on the display panel 21 as a magnified image with a clear visual distance. The optical element 22 is positioned in the middle of the optical path of the display light IMG from the display panel 21 to the user's eye 24, and its optical axis OX is arranged to connect the center of the display panel 21 screen and the user's eye. The optical element 22 is typically a convex single lens, but it can also be a lens system combining multiple lenses to achieve positive optical power as a whole. The optical element 22 constituting the lens system may include optical elements that do not have the function of forming an image; for example, it may include optical elements that efficiently allow light from the entire display panel 21 to enter the user's eye.

[0039] The venetian blind 23 is a plate-like component arranged in the optical path space occupied by the light path of the display light IMG from the optical element 22 toward the user's eye, and includes multiple light-blocking parts inside. (See reference later.) Figure 3C As described, when viewed from the optical axis OX of the optical element 22, multiple light-blocking portions of the venetian blind 23 are arranged along multiple concentric circles of different diameters. The venetian blind 23 is arranged such that the center of the concentric circles is located on the optical axis OX of the optical element 22. In other words, the venetian blind 23 is deployed in the optical path of the display light IMG from the optical unit, which guides the display light output from the display panel to the user's eye toward the user's eye.

[0040] Here, when viewed along the optical axis OX, the length of the venetian blind 23 is L1. When viewed along the optical axis OX, the distance from the user's eye position to the center of the venetian blind 23 is L2, and the distance from the center of the venetian blind 23 to the center of the optical element 22 is L3. Note that the center of the venetian blind 23 refers to the center of the light-blocking portion 5 when viewed along the optical axis OX. L1 is set in the range of 1 mm to 3 mm, L2 is set in the range of 30 mm to 30 mm, and L3 is set in the range of 5 mm to 25 mm.

[0041] The light-blocking portion 5 of the venetian blind 23 is positioned and oriented such that most of the display light IMG from the optical element 22 toward the user's eye 24 is transmitted, while blocking external light 25 toward the optical element 22. Figure 1 The external light 25, indicated by the solid line, reaches the light-blocking portion 5 of the veil 23, but is blocked there. Therefore, the external light does not pass through the light path indicated by the dotted line and is largely suppressed to reach the user's eye 24 as an external light ghosting.

[0042] Note that the head-mounted display 100 can further include another optical element. For example, as shown in Figure 2 A polarizing beam splitter PBS can be provided between the optical element 22 and the louvre 23. Alternatively, a window material EW (which is a transparent plate member) for protecting the inside of the device from dust and the like can also be provided between the louvre 23 and the user's eye 24. Even in such a case, the louvre 23 according to the present embodiment is arranged in a light path space occupied by a light path of the display light IMG directed toward the user's eye from the optical element 22.

[0043] Figure 4 is a plan view of the head-mounted display 100 according to the first embodiment as viewed from the user side. Note that, since the head-mounted display 100 is worn on the head of the user, the nose pad NF is not shown in the drawing. Figure 4 is a schematic view for explaining the arrangement of the optical system, and thus mounting tools for mounting the head-mounted display 100 on the head of the user, a communication unit for transmitting video information, a power supply unit, and the like are omitted.

[0044] The PF is a frame (i.e., a frame portion) made of a light-shielding member, functions as a housing that supports the display panel and the optical member, and is also a cover that shields external light from the front direction. The frame PF is provided with a nose pad NF for positioning on the face of the user. The window material EWR, the louvre 23R, the optical system 22R, and the display panel 21R are arranged in this order as elements for the right eye from the face side of the user, and the window material EWL, the louvre 23L, the optical system 22L, and the display panel 21L are arranged in this order as elements for the left eye from the face side of the user. As the example shown in Figure 1 If the louvre 23 also functions as a window material for protecting the inside of the device from dust and the like, the window material EWR and the window material EWL can not be provided, as the example shown in

[0045] As the display panel 21R and the display panel 21L, those having a screen aspect ratio of, for example, 4:3 or 16:9 are suitably used, but the present application is not limited thereto. The screen center of each display panel, the optical axis OX of each imaging optical system, and the center C of each louvre are arranged so as to overlap with each other when viewed from the user side. However, in order to adjust the congestion, the screen center of each display panel, the optical axis OX of each imaging optical system, and the center C of each louvre can be slightly shifted.

[0046] Further, as shown in Figure 4 By making the outer shape of the louvre substantially the same as the outer shape (e.g., the outer diameter of a convex lens or a concave mirror) of the imaging optical system, the utilization efficiency of the display light and the shielding of the external light can be balanced at a high level.

[0047] The louvre

[0048] Next, the head-mounted display 100 according to the second embodiment will be described with reference to Figures 3A to 3CThe structure of the louvers 23 is described in detail. Figure 3A is a schematic cross-sectional view illustrating a cross section of the plate-shaped louvers 23 cut in a direction perpendicular to the main surface, and Figure 3B is Figure 3A is a partial enlarged view of Figure 3C is a plan view of the main surface of the plate-shaped louvers 23 when viewed from the direction of the optical axis OX of Figure 1 , and Figure 3A is a cross-sectional view of Figure 3C illustrates a cross section taken along the line A-A' in Figure 1 In order to illustrate the mounting posture when the louvers 23 are mounted in a head-mounted display, an XYZ coordinate system corresponding to

[0049] The louvers 23 as a whole, which are plate-shaped optical elements, are optical elements in which a substrate 1 made of a light-transmitting material, a first base 2 made of a light-transmitting resin material, a second base 3 made of a light-transmitting resin material, and a light-blocking portion 5 made of a light-blocking material are integrated. In the following description, the first base 2, the second base 3, and the light-blocking portion 5 can be collectively referred to as a louver body.

[0050] In the embodiment shown in Figure 3A , the louvers 23 include the substrate 1. However, if sufficient mechanical strength is ensured by the louver body alone without the substrate 1 being provided, the substrate 1 can be omitted, and the louvers 23 can be constituted only by the first base 2, the second base 3, and the light-blocking portion 5. Conversely, when it is desired to firmly protect the first base 2, the second base 3, and the light-blocking portion 5, a substrate can be provided not only on the first base 2 side but also on the second base 3 side, and the louver body can be sandwiched between the two substrates.

[0051] The substrate

[0052] As substrate 1, either glass or optical resin materials can be used, as long as the desired optical characteristics (such as transparency) are met. Glass materials are suitable when considering that the characteristics remain largely unchanged (i.e., in terms of reliability). For example, various types of glass can be used, such as general optical glasses represented by silicate glass, borosilicate glass, and phosphate glass, quartz glass, and glass ceramics. On the other hand, when considering cost and weight reduction, resins are preferred, and examples include resins such as thermoplastic resins, thermosetting resins, UV-curable resins, and two-component curable resins. Examples of thermoplastic resins include polymethyl methacrylate (PMMA), polycarbonate, polystyrene, MS resin, AS resin, polyolefins (such as polyethylene and polypropylene), polyesters (such as polyethylene terephthalate and polybutylene terephthalate), polyvinyl chloride, cellulose acylates, thermoplastic elastomers, and cyclic olefin polymers. Examples of thermosetting resins include phenolic resins. These resins can be used alone or in combination of two or more. Note that substrate 1 can be manufactured by methods such as hot stamping, optical stamping, extrusion molding, and injection molding. The shape of the main surface of substrate 1 in a cross-sectional view is not necessarily limited to, for example, [specific method / method]. Figure 3A The flat surface shown can be selected from, for example, a concave spherical surface, a convex spherical surface, an axisymmetric aspherical surface, etc. Furthermore, the shape of the substrate 1 can be various shapes when viewed from a direction perpendicular to the main surface, and can be selected from circles, quadrilaterals, etc.

[0053] Venetian blinds

[0054] The venetian blind assembly includes a first base 2, a second base 3, and a light-blocking portion 5. The first base 2 and the second base 3 can be collectively referred to as the base. For example... Figure 3A As shown, regarding the first base 2, when assembled to a head-mounted display, the main surface of the emitting side of the display light IMG is a flat surface, and the main surface of the incident side of the display light IMG (i.e., the surface facing the second base 3) has uneven portions. Furthermore, regarding the second base 3, when assembled to a head-mounted display, the main surface of the incident side of the display light IMG is a flat surface, and the main surface of the emitting side of the display light IMG (i.e., the surface facing the first base 2) has uneven portions. Note that when using a substrate 1 whose main surface shape in a cross-sectional view is not flat, the flat surfaces of the first base 2 and the second base 3 will have a shape according to the main surface shape of the substrate 1 (i.e., a non-flat surface).

[0055] The uneven portions of the first base 2 and the uneven portions of the second base 3 mate with each other, and the first base 2 and the second base 3 are integrated. The first base 2 and the second base 3 are made of materials having substantially the same refractive index, and preferably of the same type of resin material. There are no particular limitations on the resin material used to form the first base 2 and the second base 3, as long as it meets the optical characteristics (such as transmittance and reliability), but photosensitive resin materials are preferred because they are easy to manufacture. Specifically, acrylate-based resins, polycarbonate resins, etc., are suitable. To achieve the desired optical characteristics, inorganic fine particles may also be added inside the optical resin material. The inorganic fine particles to be added are selected according to the desired optical characteristics. Specific examples include zirconium oxide, titanium oxide, zinc oxide, indium oxide, tin oxide, antimony oxide, indium tin oxide (ITO), antimony-doped tin oxide (ATO), and zinc-doped indium oxide (IZO).

[0056] The protruding and recessed portions included in the first base 2 and the second base 3 can have any shape that allows them to fit together and form a light-shielding portion 5 at a predetermined position and in a predetermined direction, as will be described later. Figure 3A and Figure 3B As shown, the zigzag shape with triangles arranged in it is suitable as a cross-sectional shape for concave and convex portions, but other shapes can be used. Examples include cross-sectional shapes in which triangles (such as isosceles triangles and right triangles), quadrilaterals, trapezoids, semicircles, etc., are arranged continuously. When from Figure 1 When viewed from above along the optical axis OX, the concave and convex portions are formed along multiple concentric circles with different diameters.

[0057] When viewing the mating part of the first base 2 and the second base 3 along the Z direction (i.e., the direction orthogonal to the main surface), the parts where the first base 2 and the first base 3 contact each other and the parts 4 where the first base 2 and the second base 3 sandwich the light-shielding part 5 are arranged alternately.

[0058] Since the interface between the surface 2a of the first base 2 and the surface 3a of the second base 3 is made of the same material, this interface has no optical function, and this portion serves as a window for transmitting the display light IMG. As described above, the venetian blind of this embodiment includes a light-transmitting portion having a predetermined width when viewed along the optical axis and a light-blocking portion arranged to sandwich each light-transmitting portion.

[0059] On the other hand, each light-shielding portion 5 is sandwiched between the 2b surface of the first base 2 and the 3b surface of the second base 3. When from Figure 1 When viewed from above along the direction of the optical axis OX, as shown... Figure 3C As shown, the light-shielding portion 5 is formed along multiple concentric circles with different diameters. Figure 1As shown in FIG. 1, the light-shielding portions 5 of the louvers 23 are arranged in such a position and posture that most of the display light IMG from the optical element 22 toward the user's eye 24 is transmitted while effectively shielding the external light 25 toward the outside of the optical element 22.

[0060] When the louvers 23 are mounted on the head-mounted display, the centers C of the plurality of concentric circles constituting the light-shielding portions 5 are arranged on the optical axis of the image-forming optical unit (i.e., the optical axis OX of the optical element 22 shown in FIG. 1). In other words, the centers C of the plurality of concentric circles constituting the light-shielding portions 5 are arranged on a line connecting the center of the screen of the display panel 21 and the position of the user's eye 24. By adopting the light-shielding portions each having a concentric circular shape, there is an advantage that the luminance uniformity of the display image becomes excellent. If the louvers are manufactured by molding or using a dispenser, there is also an advantage that the manufacturing is facilitated. For example, since stress acts isotropically, the deformation is small, and the light-shielding material can be easily applied by rotating the substrate. Figure 1 As shown in FIG. 1, when the interval between the light-shielding portions or the difference between the radii of the adjacent concentric circles is P, and the thickness of the light-shielding portions (i.e., the width of each light-shielding portion when viewed from the direction of the optical axis OX) is t, t / P is preferably 9% or less (t / P≤9%). At this time, P is preferably set in a range of 500 μm or more and 2000 μm or less, and t is preferably set in a range of 0.1 μm or more and 45 μm or less. When the length of each light-shielding portion 5 in the optical axis direction is LI, LI is preferably set in a range of 1 mm or more and 3 mm or less.

[0061] Figure 3B Therefore, in order to ensure a sufficient light-shielding effect on the external light, t is preferably 0.1 μm or more, P is preferably 2000 μm or less, and LI is preferably 1 mm or more. However, if t is set to be greater than 45 μm, P is set to be less than 500 μm, or LI is set to be greater than 3 mm, the ratio of the light-shielding portion 5 shielding the display light IMG increases, whereby the display image becomes dark. Therefore, it is preferable to set t, P, and LI in the above-described ranges, and in particular, by setting t / P≤9%, ghosting due to the external light is prevented and the luminance and uniformity of the display image can be realized with a high balance.

[0062] Since the light-shielding portion 5 only needs to shield the visible light component of the external light 25 from advancing toward the optical element 22, the light-shielding portion 5 can be formed using a light-absorbing material that absorbs visible light or a light-reflecting material that reflects visible light, and in some cases, a multilayer structure in which these materials are stacked can be adopted. Here, in the case of using a material that reflects visible light, the position and shape of the light-shielding portion 5 are set so that the reflected external light does not become stray light.

[0063] Since the light-shielding portion 5 only needs to shield the visible light component of the external light 25 from advancing toward the optical element 22, the light-shielding portion 5 can be formed using a light-absorbing material that absorbs visible light or a light-reflecting material that reflects visible light, and in some cases, a multilayer structure in which these materials are stacked can be adopted. Here, in the case of using a material that reflects visible light, the position and shape of the light-shielding portion 5 are set so that the reflected external light does not become stray light.​

[0064] As materials for absorbing visible light, coating materials comprising pigments or dyes can be suitably used, but black coating materials are preferred where enhanced light absorption properties are particularly needed, and pigment-containing materials are preferred for durability. Examples of pigments include ivory black, peach black, lampblack, pitch black, carbon black, and black aniline. Carbon black and black aniline are particularly preferred. Coloring materials can be suitably used for various purposes, such as obtaining different effects depending on the wavelength of the incident external light.

[0065] When a reflective layer is formed in the light-shielding portion, either a specular reflection type or a diffuse reflection type can be used. When using a specular reflection type, external light ghosting can be suppressed by reflecting external light in a direction that does not affect the observation of the displayed light IMG. For specular reflection type light-reflecting layers, metallic pigmented materials such as aluminum, silver, nickel, stainless steel, copper, zinc, or iron are preferably used. If fine particles of aluminum, silver, nickel, or stainless steel are used alone or in combination, a silver specular reflection type light-reflecting layer can be obtained. If fine particles of copper, zinc, or iron are used alone or in combination, a gold or copper specular reflection type light-reflecting layer can be obtained. When using a diffuse reflection type, it is easy to even out the light distribution, suppress external light ghosting, and suppress brightness unevenness. As a diffuse reflection type light-reflecting layer, pigmented materials such as silver-white, titanium-white, zinc-white, and aluminum powder are preferably used.

[0066] Furthermore, there are no particular limitations on the method used to form the light-shielding portion, and suitable manufacturing methods can be employed. For example, a coating method can be used to apply a coating material containing a coloring material to a predetermined surface of the uneven shape of the first base 2 and / or the second base 3, or a method of vacuum depositing a metallic material (such as aluminum) can be used. When the light-shielding portion 5 is formed by a coating method, a contact type or a non-contact type can be used. As a contact type, for example, there is a method of applying the coloring material using a brush, sponge, etc., which is also used for lens ink coating. As a non-contact type, for example, there is a method of applying the coloring material using a sprayer or dispenser. As will be described later, when the coating material is applied by a dispenser, an annular light-shielding portion can be formed by applying the coating material from an inclined direction toward a predetermined surface of the uneven portion of the first base 2 and / or the second base 3.

[0067] Methods of manufacturing Venetian blinds

[0068] Next, we will refer to Figures 5A to 5D and Figures 6A to 6C A method for manufacturing a venetian blind according to this embodiment is described. First, as... Figure 5AAs shown, an appropriate amount of UV-curable resin material 11 for forming the first base 2 is applied to the substrate 1. Next, as... Figure 5B As shown, resin material 11 is pressed by mold 12 to replicate the shape of the first base 2, and resin material 11 fills the space between substrate 1 and mold 12 to prevent gaps from forming. In mold 12, a pattern is formed for molding multiple concave and convex portions, each having a concentric circle shape and different diameters, onto the main surface of the first base 2.

[0069] When the filling of resin material 11 is completed, such as Figure 5C As shown, ultraviolet light is irradiated from ultraviolet light source 13 to cure the ultraviolet-cured resin material 11. When the irradiation with ultraviolet light is completed, as shown... Figure 5D As shown, the first base 2, which is formed in close contact with the substrate 1, is demolded from the mold 12. Furthermore, in order to fully cure the resin material, the resin material can be placed in an oven and subjected to heat treatment.

[0070] Next, a light-shielding portion is formed on a predetermined surface of the first base 2. That is, the light-shielding portion 5 is formed on the reference surface. Figure 3B The surface described in 2b. Specifically, as Figure 6A As shown, substrate 1 rotates around the center C of a plurality of concentric circles with different diameters as a rotation axis, and a material for the light-shielding portion 5 is applied along the surface 2b of each concentric circle using a dispenser 14. By appropriately tilting and applying the dispenser 14, the coating material containing the light-shielding material can be applied only to the surface 2b without contaminating the surface 2a. After application is completed, the light-shielding portion 5 is formed on the first base 2 by heating and firing in an oven to dry and cure the coating material.

[0071] Next, an appropriate amount of UV-curable resin material 16 for forming the second base 3 is applied to the first base 2 on which the various light-shielding portions 5 are formed. Furthermore, the resin material 16 is used to press against a template 15 that replicates the shape of the molded second base 3, and the resin material 16 fills the space between the first base 2 on which the light-shielding portions 5 are formed and the template 15 to prevent gaps from forming. The template 15 is made of a transparent material that transmits ultraviolet light, and the molding surface in contact with the resin material 16 is a flat surface.

[0072] When the filling of resin material 16 is completed, such as Figure 6B As shown, ultraviolet light is irradiated from ultraviolet light source 13 to cure the ultraviolet-cured resin material 16. When the ultraviolet irradiation is complete, the mold is demolded from the template 15, as shown. Figure 6C As shown in the diagram. Furthermore, to ensure complete curing of the resin material, it can be placed in an oven and subjected to heat treatment. Using the above manufacturing method, the close-contact double-layer louver 23 of this embodiment can be manufactured.

[0073] In the head-mounted display of the present embodiment, since the periphery of the light path space of the display light does not need to be surrounded with a light shielding member by providing the louvers 23, deterioration of the display image quality due to external light can be suppressed and high temperature and high humidity inside the head-mounted display can be suppressed. Note that in the present embodiment, the light shielding portions 5 are provided along a plurality of concentric circles, but as long as the positional deviation is within 10% of the width of the light shielding portions 5, the effects of the embodiment can be exerted.

[0074] Second Embodiment

[0075] A second embodiment, which is a modification of the first embodiment, will be described with reference to the drawings. The description of matters common to the first embodiment will be omitted or simplified. As Figure 3C The head-mounted display according to the first embodiment uses the louvers 23 having a plurality of light shielding portions 5 having different diameters formed concentrically as shown in FIG. 1. On the other hand, in the present embodiment, a louver 73 including a plurality of light shielding portions provided along a plurality of concentric circular arcs having different diameters is used.

[0076] Figure 7A is a schematic cross-sectional view of a cross section cut out in a direction perpendicular to the main surface of the plate-shaped louver 73, and Figure 7B is a plan view of the main surface of the plate-shaped louver 73 viewed from the direction of the optical axis OX of Figure 1 . Figure 7A The cross-sectional view of Figure 7B illustrates a cross section taken along the line E-E' in Figure 1 . In order to illustrate the mounting posture when the louver 73 is mounted in a head-mounted display, an XYZ coordinate system corresponding to is illustrated in each drawing.

[0077] As shown in Figure 7B , in the present embodiment, in the louver 73, the light shielding portions 5 are provided along a plurality of concentric circular arcs having different diameters. In this example, the light shielding portions 5 are formed along circular arcs having a central angle of 270 degrees, but the magnitude of the central angle is not limited to this example. Further, the number of circular arcs provided for the light shielding portions 5 is not limited to one circular arc per diameter, for example, the light shielding portions 5 can be provided along three circular arcs having the same diameter, for example, concentric circular arcs having a central angle of 90 degrees, arranged with gaps so as not to overlap each other.

[0078] The shutter 73 according to the present embodiment can have a configuration in which the light-shielding portions are not disposed in a direction in which external light does not enter due to, for example, mounting of components of the head-mounted display or a direction in which it is desired to reduce loss of display light as much as possible. Alternatively, gaps for releasing stress during manufacturing or use can be formed in the light-shielding portions having the same diameter. In the sector-shaped regions in which the light-shielding portions 5 are not provided, the first base 2 and the second base 3 formed of materials having substantially the same refractive index abut each other, and thus, the arc-shaped regions optically function as windows.

[0079] The shutter of the present embodiment can be manufactured by a manufacturing method substantially similar to that of the first embodiment. However, referring to Figure 6A The control of the described process is different from that of the first embodiment. That is, in the present embodiment, when applying the material of the light-shielding portions 5 using the dispenser 14, the timing of the ejection of the dispenser 14 is controlled so that the material is applied only to the circular arc having a central angle of 270 degrees while the substrate 1 is rotated around the center C of the concentric circular arc.

[0080] In the head-mounted display of the present embodiment, since the surrounding of the optical path space of the display light does not need to be surrounded with a light-shielding member by providing the shutter 73, it is possible to suppress the deterioration of the display image quality due to external light and suppress the high temperature and high humidity inside the head-mounted display. Note that, in the present embodiment, the light-shielding portions 5 are provided along the plurality of concentric circular arcs, but as long as the positional deviation is within 10% of the width of the light-shielding portions 5, the effects of the embodiments are exerted.

[0081] Third Embodiment

[0082] A third embodiment which is another modification of the first embodiment will be described with reference to the drawings. The description of matters common to the first embodiment will be omitted or simplified. In the present embodiment, a shutter 231 having light-shielding portions 5 formed in a plurality of elliptical shapes having different diameters is used. Figure 8A is a plan view of a main surface of the plate-shaped shutter 231 viewed from the direction of the optical axis OX in Figure 1 As shown in Figure 8A In the present embodiment, the light-shielding portions 5 are formed in a plurality of elliptical shapes having different diameters in the shutter 231.

[0083] In the shutter 231 according to the present embodiment, the pitch of the light-shielding portions (that is, the interval of the light-shielding portions arranged with the light-transmitting portions interposed therebetween) differs depending on the radial direction. For example, the pitch can be made narrow in a direction in which the incident angle of external light is large and it is desired to enhance the shielding effect of external light, and the pitch can be made wide in a direction in which the incident angle of external light is small and it is desired to reduce loss of display light as much as possible. By adopting such a configuration, it is possible to enhance the degree of design of the mounting of components of the head-mounted display.

[0084] The shutter of the present embodiment can be manufactured by a manufacturing method substantially similar to that of the first embodiment. However, referring to Figure 6A The control of the process described differs from that of the first embodiment. That is, in the present embodiment, when applying the material of the light-shielding portion 5 using the dispenser 14, the dispenser 14 is subjected to scanning control in synchronization with the rotation, so that the substrate 1 is rotated around the center C of the ellipse while the application position is changed to apply the coating material.

[0085] Fourth Embodiment

[0086] A fourth embodiment, which is another modification of the first embodiment, will be described with reference to the drawings. The description of matters common to the first embodiment will be omitted or simplified.

[0087] In the present embodiment, a shutter 232 is used, which is provided along a plurality of concentric circular arcs having different diameters and includes a plurality of light-shielding portions having different pitches depending on the direction. Figure 8B is a plan view of the main surface of the plate-like shutter 232 viewed from the direction of the optical axis OX in Figure 1 In the present embodiment, as shown in Figure 8B In the present embodiment, the light-shielding portions 5 are formed in the shutter 232 along a plurality of concentric circular arcs having different diameters.

[0088] In the shutter 232 according to the present embodiment, the pitch of the light-shielding portions (i.e., the interval of the light-shielding portions arranged across the light-transmitting portions) differs depending on the radial direction. For example, the pitch can be made narrower in a direction in which the incident angle of external light is large and in which it is desired to enhance the masking effect of external light, and the pitch can be made wider in a direction in which the incident angle of external light is small and in which it is desired to reduce the loss of display light as much as possible. By adopting such a configuration, the degree of design of the assembly mounting of the head-mounted display can be enhanced. The shutter of the present embodiment can be manufactured by a manufacturing method substantially similar to that of the second embodiment.

[0089] Fifth Embodiment

[0090] A fifth embodiment, which is another modification of the first embodiment, will be described with reference to the drawings. The description of matters common to the first embodiment will be omitted or simplified. In the present embodiment, a shutter 233 is used, which has light-shielding portions 5 formed as a plurality of circles having different centers and different diameters. Figure 8C is a plan view of the main surface of the plate-like shutter 233 viewed from the direction of the optical axis OX in Figure 1 In the present embodiment, as shown in Figure 8C In the present embodiment, the light-shielding portions 5 are formed in the shutter 233 as a plurality of circles having different centers and different diameters.

[0091] In the louvre 233 according to the present embodiment, the pitch of the light-shielding portions (i.e., the interval of the light-shielding portions arranged with the light-transmitting portions in between) differs depending on the radial direction. For example, the pitch can be made narrower in a direction in which the incident angle of external light is large and in which it is desired to enhance the masking effect of external light, and the pitch can be made wider in a direction in which the incident angle of external light is small and in which it is desired to reduce the loss of display light as much as possible. By adopting such a configuration, the design degree of the assembly mounting of the head-mounted display can be enhanced.

[0092] The louvre of the present embodiment can be manufactured by a manufacturing method substantially similar to that of the first embodiment. However, reference will be made to Figure 6A The control of the process described differs from that of the first embodiment. That is, in the present embodiment, when applying the material of the light-shielding portion 5 using the dispenser 14, the material is applied while the center of rotation of the substrate 1 is aligned with the center C of the circle to be applied.

[0093] Sixth Embodiment

[0094] A sixth embodiment, which is another modification of the first embodiment, will be described with reference to the drawings. The description of matters common to the first embodiment will be omitted or simplified. In the present embodiment, a louvre 234 having light-shielding portions 5 formed in a spiral shape is used.

[0095] Figure 8D is a plan view of the main surface of the plate-shaped louvre 234 viewed from the direction of the optical axis OX in Figure 1 As shown in Figure 8D In the present embodiment, the light-shielding portions 5 are connected in a spiral shape within the louvre 234. It can be said that a plurality of light-shielding portions arranged to sandwich a light-transmitting portion are assembled and configured as one member. The louvre of the present embodiment also includes light-shielding portions disposed to sandwich a light-transmitting portion having a predetermined width in a cross section taken along a direction orthogonal to the direction of the optical axis of the optical unit.

[0096] The louvre 234 according to the present embodiment can be mass-produced by a simple manufacturing method. In the louvre of the present embodiment, for example, a flexible transparent plate-shaped sheet is prepared, and a light-shielding material is uniformly applied to one surface of the sheet. As the application method, a simple method such as spraying, squeegee, spin coating, or the like can be adopted. Thereafter, the louvre 234 can be produced by winding the sheet into a roll shape and cutting the sheet. When the optical performance is deteriorated due to the flatness of the surface, voids, or the like, the optical performance can be improved by a method such as covering the surface with a transparent sheet or filling the voids with a transparent resin.

[0097] Examples

[0098] A specific example will be described below.

[0099] Examples 1 to 3

[0100] By referring to Figures 5A to 5D and Figures 6A to 6C The manufacturing method described above, a close contact two-layer type shutter according to the first embodiment having the structure described above is manufactured. Figures 3A to 3C

[0101] The material of the substrate 1 having a flat plate and a circular shape is prepared as an optical glass containing boron and silicon, for example, "S-BSL7" manufactured by Ohara Corporation, and the size is As a mold for forming the concave-convex portion on the first base 2, a NiP layer plated on a metal base material is cut by a precision machining machine to form a desired inverted shape of the concave-convex portion.

[0102] The first base 2 and the second base 3 are sequentially formed on one main surface of the substrate 1. The first base 2 is formed of an ultraviolet-cured acrylic resin composition. The light-shielding portion is formed by applying a coating material as a raw material of the light-shielding portion from an oblique direction using a dispenser while rotating the substrate 1 with the center of the concentric circle around the first base 2 as a rotation center. The dispenser is used because a discharge amount suitable for forming a film thickness of about 10 μm can be supplied, and the number of the concentric circles to be applied per substrate is as small as about 40, and the dispenser is compatible with the preceding and subsequent processes.

[0103] In Examples 1 to 3, the pitch P between the light-shielding portions (i.e., the interval between the adjacent light-shielding portions or the radius difference between the adjacent concentric circles) is set to different sizes. That is, P = 500 μm in Example 1, P = 1000 μm in Example 2, and P = 2000 μm in Example 3.

[0104] The thickness t of the light-shielding portion (i.e., the width of the light-shielding portion when viewed from the direction of the optical axis OX) is t = 45 μm in Example 1, t = 10 μm in Example 2, and t = 0.1 μm in Example 3. Subsequently, the second base 3 is formed of the same ultraviolet-cured acrylic resin composition as the first base 2 to produce a close contact two-layer type shutter.

[0105] In each of the examples, t / P (which is the ratio of the radial width t of the light-shielding portion to the radial pitch P of the light-shielding portion or the interval between the light-shielding portions) is t / P = 9% in Example 1, t / P = 1% in Example 2, and t / P = 0.005% in Example 3.

[0106] ​The shutters of Examples 1 to 3 were incorporated into each of the head-mounted displays, respectively, for evaluation of external light ghosting and brightness unevenness, and visual evaluation of the external light ghosting and brightness unevenness was performed under an illumination space arranged for evaluation. As a result of the evaluation, in the shutters of Examples 1 to 3, it was confirmed that the external light ghosting was reduced to a level at which the external light ghosting could not be visually recognized, and the brightness unevenness could hardly be visually recognized. That is, the display image was more easily seen compared to the case where the shutter was not provided.

[0107] Examples 4 to 6

[0108] By referring to Figures 5A to 5D and Figures 6A to 6C manufacturing method described, a close contact two-layer type shutter according to the second embodiment having a structure described with reference to Figures 7A to 7B was manufactured.

[0109] In Examples 4 to 6, the pitch P between the light shielding portions (i.e., the interval between adjacent light shielding portions or the difference in radius between adjacent concentric circular arcs) was set to different sizes. That is, P = 500 pm in Example 4, P = 1000 pm in Example 5, and P = 2000 pm in Example 6. The thickness t of the light shielding portion (i.e., the width of the light shielding portion when viewed from the direction of the optical axis OX) was t = 45 pm in Example 4, t = 10 pm in Example 5, and t = 0.1 pm in Example 6.

[0110] The light shielding portion was formed by rotating the substrate 1 by 270 degrees while using a dispenser to apply a coating material as a raw material of the light shielding portion from an oblique direction with the center of the concentric circle around the first base portion 2 as a rotation center.

[0111] The shutters of Examples 4 to 6 were incorporated into each of the head-mounted displays, respectively, for evaluation of external light ghosting and brightness unevenness, and visual evaluation of the external light ghosting and brightness unevenness was performed under an illumination space arranged for evaluation. As a result of the evaluation, in the shutters of Examples 4 to 6, it was confirmed that the external light ghosting was reduced to a level at which the external light ghosting could not be visually recognized, and the brightness unevenness could hardly be visually recognized. That is, the display image was more easily seen compared to the case where the shutter was not provided.

[0112] Examples 7 to 8

[0113] In Examples 7 to 8, the pitch P between the light shielding portions (i.e., the interval between adjacent light shielding portions or the difference in radius between adjacent concentric circles) and the radial width t of the light shielding portion were different from those in Examples 1 to 3. The other configurations were the same as in Examples 1 to 3. That is, the pitch P between the light shielding portions was P = 100 pm in Example 7, and P = 3000 pm in Example 8.

[0114] The thickness t of the light-shielding portion (i.e., the width of the light-shielding portion when viewed from the direction of the optical axis OX) was t = 50 μm in Example 7 and t = 0.01 μm in Example 8.

[0115] The shutters of Examples 7 to 8 were incorporated into each of the head-mounted displays for evaluation of external light ghosting and luminance unevenness, and visual evaluation of the external light ghosting and the luminance unevenness was performed in the same manner as in the other examples.

[0116] In the shutter of Example 7, the external light ghosting was reduced to a level that could not be visually recognized compared to the case where the shutter was not provided, and the display image was very easy to see. However, the evaluation regarding the luminance unevenness of the display image was low compared to the case where the shutter of Examples 1 to 3 was incorporated.

[0117] In the shutter of Example 8, the external light ghosting was significantly reduced compared to the case where the shutter was not provided, and the display image was easy to see. However, the evaluation regarding the effect of reducing the external light ghosting was low compared to the case where the shutter of Examples 1 to 3 was incorporated, and the evaluation regarding the luminance unevenness was equivalent.

[0118] According to Examples 7 to 8, because the external light ghosting can be reduced compared to the case where the shutter is not provided, the image quality of the display image can be significantly improved. As described above, if any of the shutters of Examples 1 to 8 is incorporated into the head-mounted display, the periphery of the space of the optical path of the display light does not need to be surrounded with the light-shielding member, so the degradation of the display image quality due to external light can be suppressed, and the high temperature and high humidity inside the head-mounted display can be suppressed. However, it can be said that Examples 1 to 3 and Examples 4 to 6 are preferable examples because both the reduction of the external light ghosting and the suppression of the luminance unevenness can be achieved at a higher level compared to Examples 7 and 8.

[0119] Other Embodiments

[0120] Note that the present application is not limited to the above-described embodiments and examples, and many modifications can be made within the technical concept of the present application. For example, a light-shielding portion having a concentric circular shape and a light-shielding portion having a concentric circular arc shape can coexist in one shutter. Until a certain radius, the light-shielding portion can be formed along a concentric circle, and for a radius exceeding the radius, the light-shielding portion can be formed along a concentric circular arc. Conversely, until a certain radius, the light-shielding portion can be formed along a concentric circular arc, and for a radius exceeding the radius, the light-shielding portion can be formed along a concentric circle.

[0121] Further, the light-shielding portions do not necessarily have to be formed along a perfectly concentric circle or a perfectly concentric circular arc, and deformations to the extent that substantially equivalent effects can be obtained can be allowed. That is, as long as substantially equivalent brightness uniformity of a display image can be obtained, or substantially equivalent ease of manufacture can be achieved when the louvers are manufactured by molding with a die, it is acceptable.

[0122] For example, the light-shielding portions can be provided along a plurality of ellipses or portions of ellipses having a common focus and different lengths of diameters. Alternatively, the light-shielding portions can also be provided along a plurality of annular shapes having different areas of enclosed portions, the same center of gravity positions, and outer edges that do not intersect each other.

[0123] The louvers according to the present application can be provided in optical devices other than head-mounted displays, and can be mounted on, for example, a hand-held display, a camera that captures still images or moving images, a microscope, or an endoscope.

[0124] Other Embodiments

[0125] While the present application has been described with reference to exemplary embodiments, it is to be understood that the application is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1.A head-mounted display comprising: an optical unit configured to direct display light emitted from a display panel to a user's eye; and a louver disposed in a light path of the display light from the optical unit toward the user's eye, wherein the louver includes light-transmissive portions having a predetermined width and light-blocking portions disposed to sandwich the light-transmissive portions when viewed in a direction of an optical axis of the optical unit, wherein, in a case where the louver is viewed from the direction of the optical axis of the optical unit, each of the light-blocking portions is arranged at a predetermined interval from each other along a plurality of circles having different diameters or a plurality of circular arcs having different diameters. 2.The head-mounted display according to claim 1, wherein the plurality of circles are a plurality of concentric circles having different diameters, and the plurality of circular arcs are a plurality of concentric circular arcs having different diameters. 3.The head-mounted display according to claim 2, wherein centers of the plurality of concentric circles having different diameters or centers of the plurality of concentric circular arcs having different diameters are located on the optical axis of the optical unit. 4.The head-mounted display according to any one of claims 1 to 3, wherein the light-blocking portions are made of a light-blocking material and are provided inside a plate-shaped base made of a light-transmissive material. 5.The head-mounted display according to any one of claims 1 to 3, wherein in a cross section of the louver taken along the direction of the optical axis of the optical unit, the louver includes a first base having a concave-convex shape and a second base having a concave-convex shape that cooperates with the concave-convex shape of the first base, and the light-blocking portions are sandwiched between the first base and the second base. 6.The head-mounted display according to any one of claims 1 to 3, wherein in a cross section of the louver taken along a direction orthogonal to the direction of the optical axis of the optical unit, a width of each of the light-blocking portions is 9% or less of an interval between the light-blocking portions arranged across the light-transmissive portions. 7.The head-mounted display according to claim 6, wherein the interval between the light-blocking portions is 500 µm or more and 2000 µm or less. 8.The head-mounted display according to claim 6, wherein the width of each of the light-blocking portions is 0.1 µm or more and 45 µm or less. 9.The head-mounted display according to any one of claims 1 to 3, wherein the light-blocking portions are formed of a light-absorbing material or a light-reflecting material. ​

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