Diffractive optical component and virtual image display device

Abstract

A diffractive optical component and a virtual image display device can avoid or suppress the intrusion of moisture into the interior caused by, for example, a capillary phenomenon. The diffractive optical component (300) comprises: a hologram element (310); a supporting substrate (SS) which contacts the hologram element (310) from one side and supports the hologram element (310); and a covering film component (BFa) as a first film component which contacts the hologram element (310) from the opposite side of the one side and covers the hologram element (310), the covering film component (BFa) having a connecting portion (CN) in contact with the supporting substrate (SS), and the connecting portion (CN) is separated from the hologram element (310).

Description

Technical Field

[0001] The present invention relates to a diffractive optical component for guiding light that can be used in a virtual image display device for presenting a virtual image to an observer, and a virtual image display device having the diffractive optical component. Background Art

[0002] As a diffractive optical component applicable to a virtual image display device, there is disclosed a diffractive optical component in which a dielectric film is disposed around a hologram element to prevent intrusion of moisture from the outside (Patent Document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2019-148738

[0004] However, in the above-mentioned technique, depending on the materials used, manufacturing conditions, etc., there is a possibility that moisture may penetrate into the hologram element due to, for example, a capillary phenomenon, at the interface of a member covering the hologram element formed of a dielectric film or the like. Summary of the invention

[0005] A diffractive optical component according to one aspect of the present invention comprises: a hologram element; a supporting substrate which contacts the hologram element from one side and supports the hologram element; and a first film component which contacts the hologram element from the side opposite to the one side and covers the hologram element, the first film component having a connecting portion which contacts the supporting substrate and is separated from the hologram element. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1 It is a perspective view for explaining the appearance of a head mounted display including the diffractive optical component according to the first embodiment.

[0007] Figure 2 is the ray diagram of the optical system in the head mounted display.

[0008] Figure 3 This is a schematic diagram of a diffractive optical component.

[0009] Figure 4 This is a schematic longitudinal sectional view of an example of a diffractive optical component.

[0010] Figure 5 It is a schematic longitudinal sectional view of a diffractive optical component according to a modified example.

[0011] Figure 6 It is a schematic longitudinal sectional view of a diffractive optical component according to the second embodiment.

[0012] Figure 7 It is a schematic longitudinal sectional view of a diffractive optical component according to the third embodiment.

[0013] Figure 8This is another example of a ray diagram of an optical system in a head-mounted display.

[0014] Description of symbols

[0015] 10: optical system; 31: image light generating device; 32: projection optical system; 32a: lens; 32b: lens; 40: first reflector; 40s: reflecting surface; 50: first diffractive optical component; 60: second reflector; 60s: reflecting surface; 70: second diffractive optical component; 100, 100A, 100B: display device; 201: frame; 300: diffractive optical component; 310: hologram element; 310c: central part (central area); 310p: peripheral part (edge ​​area); 321: first substrate; 322: second substrate; 331: supporting side dielectric film; 332: covering side dielectric film; 335: outer surface dielectric film; 340: adhesive layer (adhesive component); 610: optical system; 632: projection optical system; 632a: lens; 660: light guide system; 661: lens system; 661a: lens; 662: reflector; 662s: reflecting surface; AP: gas part; BFa: covering film part; BFb: supporting side film part; BM1: first substrate part; BM2: second substrate part; CC: covering substrate; CN: connecting part; CS: connecting surface; DF: dielectric film; EY: eye; IL: image light; L10, L20, L30, L40: optical part; MD: outermost dielectric film; P1, P2: intermediate image; PU, R0, R1: exit pupil; SB: substrate; SS: supporting substrate; T, T1: thickness; US: wearer (user); W: width; α, β: state. DETAILED DESCRIPTION

[0016] [First embodiment]

[0017] Below, refer to Figure 1 A configuration example of a diffractive optical component according to the present embodiment and a head mounted display as an example of a virtual image display device including the diffractive optical component will be described.

[0018] Figure 1 1 is a perspective view showing an appearance of a head mounted display (hereinafter, also referred to as HMD) 200 including a display device 100 as a virtual image display device of the present embodiment, that is, an appearance of a head mounted display device. Figure 2 is a light diagram of the optical system 10 in the display device 100. And, Figure 3 The present invention is about the diffractive optical components 50 and 70 (see Figure 2 ) and a schematic longitudinal sectional view and a front view of the structure of the diffractive optical component 300 used. In addition, for example, Figure 3 In order to make each layer and each component of each part constituting the diffractive optical component 300 have a size that can be recognized, the thickness and thickness ratio of each layer and each component are shown in a state different from the actual state. Figure 3 In the example shown in FIG. 1 , the diffractive optical component 300 is shown as a flat plate, but it is also possible to consider Figure 2 In the case of a curved surface shape like the second diffractive optical member 70 (see Figure 5 ).

[0019] like Figure 1 As shown, the HMD 200 includes a display device 100A for the right eye, a display device 100B for the left eye, and a frame 201 supporting them. Each display device 100A, 100B generates image light IL and guides the generated image light IL to the eyes of the left and right eyes EY of the observer or wearer, so that the image light IL can be observed in a state of overlapping with the external image. Thus, it is possible to perform AR (Augmented Reality) display of virtual visual information such as adding images and data overlapping with external images or objects.

[0020] In addition, the structure of the second diffractive optical member 70 as the fourth optical portion L40 disposed in front of the eye EY in order to extract the image light IL in the HMD 200 will be described in detail later.

[0021] exist Figure 1 In the above, X, Y, and Z are orthogonal coordinate systems, the +X direction corresponds to the horizontal direction of the binocular EY arrangement of the observer or wearer wearing the HMD 200 including the display device 100, the +Y direction corresponds to the upper direction orthogonal to the horizontal direction of the binocular EY arrangement for the wearer US, and the +Z direction corresponds to the front or front direction for the wearer US. Figure 1 In the embodiment, not only the display device 100A for the right eye but also the display device 100B for the left eye are described, but the display device 100A for the right eye and the display device 100B for the left eye are optically reversed left and right, and the display device 100A for the right eye is described as a representative display device 100. For example, in Figure 2 , a light diagram of the optical system 10 is shown for the display device 100A for the right eye.

[0022] Below, refer to Figure 2 The light diagram shown in FIG. 1 illustrates a configuration example of the optical system 10 in the display device 100 .

[0023] exist Figure 2In one example, the optical system 10 of the display device 100 includes, from the light source side, an image light generating device 31, a projection optical system 32, a first reflector 40, a first diffraction optical component 50 as a reflective diffraction element, a second reflector 60, and a second diffraction optical component 70 as a reflective diffraction element.

[0024] The image light generating device 31 in the optical system 10 includes a light source and generates image light IL. As the image light generating device 31, for example, a display panel such as an organic EL display element can be used. In this case, a display device 100 that is compact and capable of displaying images with high image quality can be provided. In addition, the image light generating device 31 can also be a display panel having an illumination light source (not shown) and a liquid crystal display element that modulates the illumination light emitted from the illumination light source. In addition, as the image light generating device 31, a method of modulating laser light using a micromirror device can also be used. In addition, in the example shown in the figure, the image light generating device 31 is set to have a single display panel that can display in color, but the image light generating device 31 can also be composed of a plurality of display panels corresponding to each color and a synthetic optical system that synthesizes the image light of each color from them.

[0025] The projection optical system 32 in the optical system 10 includes a rotationally symmetric lens 32 a and a free-form surface lens 32 b , and projects the image light IL emitted from the image light generating device 31 toward the subsequent stage of the optical path.

[0026] The first reflector 40 has a concave reflective surface 40s and has a positive refractive power. The first reflector 40 is arranged at a midway position of the optical path from the projection optical system 32 to the first diffractive optical component 50. The projection optical system 32 forms a first intermediate image P1 on the reflective surface of the first reflector 40 or in the vicinity thereof. In addition, the first reflector 40 can also be understood as a component of the projection optical system 32.

[0027] The second reflector 60 has a concave reflective surface 60s, which has a positive refractive power. The reflective surface 60s can be a spherical surface, an aspherical surface, or a free-form surface. Here, the reflective surface 60s is a free-form surface. The second reflector 60 reflects the image light IL diffracted by the first diffractive optical component 50 toward the second diffractive optical component 70. In addition, a second intermediate image P2 of the image light IL is formed between the second reflector 60 and the second diffractive optical component 70.

[0028] The first diffractive optical component 50 and the second diffractive optical component 70 are composed of reflective volume hologram elements. The second diffractive optical component 70 has a concave surface and has a positive refractive power. In this embodiment, by providing a structure for sealing the hologram element in the first diffractive optical component 50 and the second diffractive optical component 70, the diffraction state is maintained in a desired state, and the image formation in the display device 100 is well maintained. In addition, for the structure related to the first diffractive optical component 50 or the second diffractive optical component 70, refer to Figure 3 The details will be described later.

[0029] In addition, in the above-mentioned embodiment, the portion other than the image light generating device 31 in the optical system 10 can also be understood to include the first optical portion L10 composed of the projection optical system 32 and the first reflector 40, the second optical portion L20 composed of the reflective first diffractive optical component 50, the third optical portion L30 composed of the second reflector 60, and the fourth optical portion L40 composed of the reflective second diffractive optical component 70. In one example here, the second intermediate image P2 of the image light IL is formed between the third optical portion L30 and the fourth optical portion L40, that is, between the second reflector 60 and the second diffractive optical component 70, and further, the fourth optical portion L40 (second diffractive optical component 70) collimates the image light to form an exit pupil PU. The exit pupil PU is a position assumed to be the position of the observer's eye EY.

[0030] According to the structure of the optical system 10 as described above, the optical path of the image light IL is more specifically as follows. First, the image light generating device 31 emits the image light IL toward the first optical part L10 composed of the projection optical system 32 and the like. Then, the first optical part L10 emits the image light IL incident on the projection optical system 32 toward the second optical part L20 composed of the first diffractive optical component 50. In addition, an emission pupil R0 is formed between the rotationally symmetrical lens 32a and the free-form lens 32b constituting the projection optical system 32, and a first intermediate image P1 is formed before and after the reflection surface 40s of the first reflector 40. Furthermore, the reflective first diffractive optical component 50 emits the incident image light IL toward the third optical part L30, which is a light guide system and is composed of the second reflector 60. That is, the first diffractive optical component 50 bends the optical path of the image light IL by the diffraction effect. The second reflector 60 emits the incident image light IL toward the fourth optical part L40 formed by the second diffractive optical component 70 at the reflecting surface 60s. The second diffractive optical component 70 collimates the incident image light IL and emits it toward the eye EY of the observer, forming an emission pupil PU. That is, the eye EY of the observer is located at the position of the emission pupil PU in the above structure, and thus each light ray constituting the image light IL is imaged as a single point on the retina of the eye EY, so that a virtual image based on the image light IL can be seen. In addition, an emission pupil R1 is formed between the second reflector 60 and the second diffractive optical component 70.

[0031] Below, refer to Figure 3 An example of the structure of the first diffractive optical component 50 or the second diffractive optical component 70 is described. Figure 3 , the longitudinal sectional view schematically shown as state α and the front view schematically shown as state β conceptually show an example of a diffractive optical component 300 having a structure that can be applied as the first diffractive optical component 50 or the second diffractive optical component 70. Figure 3 In other words, the state α in the cross section is a state observed from the normal direction of the cross section of each part that is formed in layers and constitutes the diffractive optical component 300. In addition, as shown in the figure below, the lateral direction in which each layer extends when viewed in section is set as the ±x direction, the longitudinal direction in which each layer is arranged is set as the ±y direction, and the normal direction is set as the ±z direction. Among them, the -y side is set as the lower side, and the +y side is set as the upper side. In addition, in order to facilitate the understanding of the structure, the size (such as thickness) of each part is exaggerated than the actual size.

[0032] As shown in the state α, the diffractive optical component 300 of this embodiment is composed of a plurality of components stacked in layers in the +y direction, and specifically includes: a hologram element 310; a supporting substrate SS supporting the hologram element 310; a cover film component BFa covering the hologram element 310; a cover substrate CC covering the cover film component BFa; and an adhesive layer 340 composed of an adhesive component for bonding the supporting substrate SS, the cover film component BFa, and the cover substrate CC. Here, the cover film component BFa is also set as the first film component.

[0033] The hologram element 310 is a plate-shaped component having a thickness T of about 80 μm, for example. In the central portion (central area) 310c, interference fringes are formed by exposing the holographic photosensitive layer having a sensitivity corresponding to a predetermined wavelength to interference light and reference light, thereby providing a volume hologram element. That is, the hologram element 310 functions as a diffraction hologram element by deflecting the light incident on the central portion 310c. Figure 3 In the figure, the central part 310c is indicated by hatching, and a peripheral part (edge ​​area) 310p is formed around the central part 310c not marked with hatching. The peripheral part 310p does not have the diffraction effect like the central part 310c, for example, it has high light transmittance, allowing visible light such as image light and external light to pass through. That is, the peripheral part (edge ​​area) 310p does not form interference fringes. Here, the central part (center area) 310c is also set as the first area. In addition, the peripheral part 310p is also set as the second area.

[0034] The supporting substrate SS contacts the hologram element 310 from one side (-y side) and supports the hologram element 310. The supporting substrate SS is composed of a transparent substrate (translucent substrate) and the like, and transmits visible light such as image light and external light. Here, the supporting substrate SS is composed of a first substrate member BM1 and a supporting side film member BFb provided on the first substrate member BM1. For a more specific structural example of the first substrate member BM1, refer to Figure 4 This will be described later. Here, the support-side film member BFb is also used as the second film member.

[0035] The supporting-side film member BFb (second film member) is a member forming the outermost layer in contact with the hologram element 310 in the supporting base material SS, supports the hologram element 310, and is in contact with the covering film member BFa (first film member) at a portion separated from the hologram element 310. The supporting-side film member BFb may be composed of the same member as the covering film member BFa, for example.

[0036] The cover film member BFa has a thickness of, for example, about 25 μm, is composed of a transparent and adhesive belt-shaped member, and contacts with the hologram element 310 from the opposite side (+y side) of the support substrate SS to cover the hologram element 310. As shown in the state β, when the diffractive optical component 300 is observed with respect to the xz plane, it can be seen that the cover film member BFa has a connection portion CN in contact with the support substrate SS at a position separated from the hologram element 310. In the case of the illustrated embodiment, as described above, the outermost layer of the support substrate SS is formed by the support side film member BFb, so the cover film member BFa contacts with the support side film member BFb to form the connection portion CN. In other words, the range of the cover film member BFa in contact with the support side film member BFb becomes the connection portion CN. In this case, for example, as shown in state β, the connection part CN is formed at the end side separated from the hologram element 310 so as to surround the hologram element 310, whereby the hologram element 310 is sandwiched by the cover film member BFa and the support base material SS including the support side film member BFb to be in a sealed state. In order to ensure the desired sealed state, the cover film member BFa and the support side film member BFb are composed of members having a certain thickness T1 (for example, about 25 μm). As the cover film member BFa and the support side film member BFb, for example, a resin tape is used to ensure the barrier property against moisture, and it is considered that the thickness T1 is preferably at least about 10 μm or more. Here, as an example, it is considered that a TESA (registered trademark) tape, which is a tape-shaped member (double-sided tape) with a thickness of 25 μm and sufficient transparency (for example, a light transmittance of more than 90%), is used as the cover film member BFa and the support side film member BFb to ensure sufficient water resistance and adhesion. Furthermore, by adopting such a structure, even when moisture is generated from the adhesive layer (adhesive member) 340, water infiltration caused by the moisture can be avoided or suppressed.

[0037] In the above embodiment, the connection part CN in the cover film member BFa forms a connection surface CS having a width W of 2 mm or more and in contact with the support substrate SS or the support side film member BFb. By having a width W of 2 mm or more as the connection surface CS, the above-mentioned sealed state of the connection part CN can be reliably maintained.

[0038] In addition, in the above-mentioned structure, the gas portion AP is formed between the hologram element 310 and the connection portion CN as the connection portion CN is formed separately. That is, as shown in a partial enlargement, the gas portion AP is formed between the cover film member BFa, the hologram element 310 and the supporting substrate SS through the connection at the connection portion CN. In this case, the hologram element 310 has a certain thickness T (for example, a thickness of about 80 μm), and the connection portion CN is appropriately separated from the hologram element 310, thereby ensuring that the space of the gas portion AP is of sufficient size. As a result, for example, the following situation can be avoided: at the interface between the cover film member BFa and the supporting substrate SS, water intrudes due to the capillary state. In addition, it is conceivable to set the gas portion AP to a state filled with an inert gas. For example, when manufacturing the diffractive optical component 300, the above-mentioned method can be achieved by performing the sealing operation of the hologram element 310, that is, forming the gas portion AP, in a nitrogen environment.

[0039] On the other hand, for example, as shown in state α, when observing from the normal direction of the cross section including the hologram element 310, the supporting substrate SS and the covering film component BFa (the first film component), the peripheral portion 310p (the second region) is provided between the connecting portion CN and the central portion 310c (the first region). In this case, as shown in state β, in the hologram element 310, by providing the peripheral portion 310p (the second region) with an appropriate size, it is possible to separate the gas portion AP from the central portion 310c (the first region) through which the component light that contributes to the image passes. Thus, for example, when the diffractive optical component 300 is used as the second diffractive optical component 70, that is, as a component arranged in front of the eye, by providing the peripheral portion 310p, it is possible to keep the gas portion AP away from the visual confirmation range and maintain the perspective well. In more detail, in this case, first, when the diffractive optical component 300 is used as the second diffractive optical component 70, it is arranged in front of the user ( Figure 1 In front of the eyes of the wearer US), a peripheral portion (edge ​​region) 310p without a holographic function is provided outside the central portion (center region) 310c in the holographic element 310, which is a virtual image display region having a holographic function and contributing to the virtual image display. In addition, the connecting portion CN is formed further outside the peripheral portion (edge ​​region) 310p. In this case, by providing the peripheral portion (edge ​​region) 310p, for example, the gas portion AP formed while maintaining a state of being separated from the connecting portion CN is removed from the user ( Figure 1 The lens is kept away from the eyes of the wearer (US), thereby maintaining (ensuring) the perspective in a good state.

[0040] In the above-described embodiment, no air layer is provided at locations other than the gas portion AP, i.e., between the covering film component BFa and the hologram element 310 and between the supporting side film component BFb and the hologram element. Thus, unexpected refraction due to the difference in refractive index between the air layer and the hologram element 310 will not occur, thereby ensuring good transparency.

[0041] The covering substrate CC is a component that covers the hologram element 310 from the opposite side (+y side) of the supporting substrate SS. As shown in the figure, the covering substrate CC covers the covering film component BFa. That is, the covering substrate CC covers the hologram element 310 together with the covering film component BFa by covering the covering film component BFa. In addition, the covering substrate CC can also be regarded as covering the hologram element 310 and the covering film component BFa in cooperation with the supporting substrate SS. In addition, the covering substrate CC is composed of a transparent substrate (translucent substrate) and the like, and is a component that allows visible light such as image light and external light to pass through. Here, it is composed of the second substrate component BM2. For a more specific structural example of the second substrate component BM2, refer to Figure 4 This will be described later.

[0042] The adhesive layer (adhesive member) 340 is made of a transparent material (adhesive), and is formed between the supporting substrate SS and the covering substrate CC. It adheres and fixes the hologram element 310 and the covering film member BFa together, so that the whole of the diffractive optical member 300 is integrated. In addition, when the adhesive layer 340 is formed, that is, when it is adhered, it absorbs the convex step generated by the stacking from the supporting side film member BFb to the covering film member BFa, and the gap difference between the supporting substrate SS and the covering substrate CC. As the material of the adhesive layer 340, for example, epoxy resin and a material having a certain degree of water resistance can be used. In addition, as the above material, it is considered that the hologram element 310 will not be exposed to high temperature for a long time and the holographic performance will not be deteriorated by using, for example, ultraviolet curing materials. In addition, if there is no problem in performance, in addition to the above, as the material of the adhesive layer 340, for example, acrylic resin, silicone resin, polyester resin, polyurethane resin, or polyvinyl acetate resin can be used. In addition, for example, it is also conceivable to use a thermosetting resin in addition to the ultraviolet curing resin.

[0043] Below, refer to Figure 4 As a more specific structural example of the diffractive optical component 300, an example showing the first substrate component BM1 and the second substrate component BM2 will be described. Figure 4 In order to make the structure easier to understand, the size of each part (such as thickness) is also exaggerated than the actual size. Figure 4In one example, the first substrate member BM1 constituting the supporting base material SS is constituted by a substrate SB (first substrate 321) and a supporting side dielectric film 331 (dielectric film DF) formed on the first substrate 321. The second substrate member BM2 constituting the covering base material CC is constituted by a substrate SB (second substrate 322) and a covering side dielectric film 332 (dielectric film DF) formed on the second substrate 322. Therefore, as shown in one example in the figure, when viewed from the normal direction of the cross section including the hologram element 310, the first substrate 321 and the second substrate 322 (covering film member BFa), that is, the cross section cutting across the portions formed in layers, the supporting side film member BFb is provided between the hologram element 310 and the supporting side dielectric film 331. In addition, when viewed from the normal direction of the cross section including the hologram element 310, the first substrate 321, and the second substrate 322 (cover film member BFa), that is, the cross section across the respective portions formed in a layered form, the adhesive layer (adhesive member) 340 is provided between the cover film member BFa and the cover-side dielectric film 332. Here, the support-side dielectric film 331 (dielectric film DF) is also provided as the first dielectric film. The cover-side dielectric film 332 (dielectric film DF) is also provided as the second dielectric film.

[0044] Here, in the case of the diffractive optical component 300 having the above-mentioned structure, in addition to the water resistance of the above-mentioned cover film component BFa and the support side film component BFb, it is necessary to sufficiently improve the adhesion (joining) between the cover film component BFa, the support side film component BFb and other components when protecting the hologram element 310. More specifically, it is necessary to ensure the adhesion between the first substrate component BM1 and the support side film component BFb, and the adhesion between the first substrate component BM1 and the second substrate component BM2 and the adhesive layer 340. Therefore, in the above example, in the first substrate component BM1 and the second substrate component BM2, a dielectric film DF as an inorganic material film, that is, a supporting side dielectric film 331 (first dielectric film) and a covering side dielectric film 332 (second dielectric film) are provided in the outermost layer which becomes the contact part with other components, so that even if a material that cannot ensure tight adhesion is used in each substrate SB, that is, the first substrate 321 and the second substrate 322, the tight adhesion required for manufacturing the diffraction optical component 300 can be ensured.

[0045] Each substrate SB, i.e., the first substrate 321 and the second substrate 322, is a transparent substrate made of resin that allows visible light such as image light and external light to pass through. As the constituent material of the first substrate 321 and the second substrate 322, for example, resin materials such as polyethylene terephthalate, polyethylene naphthalate, polypropylene, cycloolefin polymer, polyamide, polyether sulfone, polymethyl methacrylate, polycarbonate, polyarylate, glass materials such as quartz glass, soda glass, etc. can be considered to be applied, and one of them or a combination of two or more can be used. The average thickness of such the first substrate 321 and the second substrate 322 is not particularly limited, but is preferably about 0.5 mm or more and about 5 mm or less, and more preferably about 0.7 mm or more and about 2 mm or less.

[0046] Each dielectric film DF, that is, the support-side dielectric film 331 and the cover-side dielectric film 332 is formed by, for example, forming aluminum oxide (Al2O3) with a thickness of about 60 nm. 2 O 3 ) is formed on the substrate SB. In this case, the support side dielectric film 331 forms the outermost layer of the first substrate component BM1, and the cover side dielectric film 332 forms the outermost layer of the second substrate component BM2. Therefore, the support side dielectric film 331 is a surface-forming film that contacts with the adhesive layer (adhesive component) 340 and the support side film component BFb to form an interface, and the cover side dielectric film 332 is a surface-forming film that contacts with the adhesive layer (adhesive component) 340 to form an interface. The support side dielectric film 331 and the cover side dielectric film 332 composed of the above-mentioned materials have appropriate adhesion to the first substrate component BM1 and the second substrate component BM2 and the adhesive layer 340.

[0047] In addition, as the constituent material of each dielectric film DF, i.e., the supporting side dielectric film 331 and the covering side dielectric film 332, as long as it satisfies various requirements such as having dielectric properties and being able to impart water resistance (water vapor barrier properties) and transparency to the supporting side dielectric film 331, etc., in addition to the above-mentioned example, it is also possible to consider constituting it with various materials, thicknesses, etc. Specifically, for example, in addition to inorganic materials such as ceramic materials and glass materials, it is also possible to consider applying resin materials, etc. As ceramic materials, for example, aluminum oxide, zirconium oxide, magnesium oxide, silicon dioxide, silicon monoxide, titanium dioxide, hafnium oxide, aluminum nitride, silicon nitride, silicon carbide, barium titanate, etc. can be applied, and one of them or a combination of two or more of them can be used. Among them, silicon monoxide (SiO), silicon dioxide (SiO 2 ), hafnium oxide (HfO 2 )、ZrO 2 ) and titanium dioxide (TiO 2). In addition, if it is a ceramic material, the support side dielectric film 331 and the covering side dielectric film 332 can be formed relatively easily using a vapor deposition method such as vacuum evaporation, sputtering, ion plating, and plasma chemical vapor deposition. In addition, as a glass material, for example, quartz glass, borosilicate glass, etc. can be used. In addition, as a resin material, for example, polyvinyl chloride, polyethylene, polypropylene, polytetrafluoroethylene, polyethylene terephthalate, polyvinyl fluoride, epoxy resin, phenolic resin, etc. can be used. In addition, the support side dielectric film 331 and the covering side dielectric film 332 can be a single layer body composed of the above-mentioned constituent materials, or a multilayer body, but preferably a multilayer body. In the case of a multilayer body, for example, as the support side dielectric film 331, it can be set to have a layer composed of silicon monoxide (SiO) and a layer composed of aluminum oxide (Al 2 O 3 ) and having a layer composed of silicon monoxide (SiO) as the first substrate 321 side, or having a layer composed of silicon monoxide (SiO) and a layer composed of hafnium oxide (HfO 2 ) and a multilayer body with silicon monoxide (SiO) as the first substrate 321 side. The average thickness of the support-side dielectric film 331 and the cover-side dielectric film 332 is not particularly limited, but in order to maintain sufficient water vapor barrier properties and avoid film cracks, it is preferably about 50nm to 1μm, and more preferably about 100nm to 300nm.

[0048] In addition, as an example of the manufacturing process of the diffractive optical component 300, the following process can be considered. First, the first substrate component BM1 and the second substrate component BM2 having the above-mentioned structure are respectively produced, and then, the supporting side film component BFb is provided on the first substrate component BM1 by attaching a tape component or the like. Thus, the supporting substrate SS and the covering substrate CC (the second substrate component BM2) are prepared. Next, the hologram element 310 is provided on the supporting substrate SS, that is, on the supporting side film component BFb, and the hologram element 310 is covered by the covering film component BFa composed of a tape component or the like, and the hologram element 310 is sealed (sealed) by the covering film component BFa and the supporting side film component BFb. At this time, the gas portion AP and the connecting portion CN (connecting surface CS) are formed at the same time. Finally, an adhesive to be the adhesive layer 340 is applied to the covering film component BFa, and the covering substrate CC covers the adhesive, and the adhesive is cured by ultraviolet irradiation or the like, thereby manufacturing the diffractive optical component 300.

[0049] In addition, regarding the structure of the diffractive optical component 300, as described above, or as Figure 5 As shown in a modified example in a schematic longitudinal sectional view, it can also be applied to a curved surface shape such as a spectacle lens. Figure 2The diffractive optical component 300 can be applied to the second diffractive optical component 70 shown in FIG.

[0050] As described above, the diffractive optical component 300 of the present embodiment comprises: the hologram element 310, the supporting substrate SS which is in contact with the hologram element 310 from one side and supports the hologram element 310, and the covering film member BFa as the first film member which is in contact with the hologram element 310 from the opposite side to the one side and covers the hologram element 310, the covering film member BFa having the connecting portion CN in contact with the supporting substrate SS, and the connecting portion CN being separated from the hologram element 310. In the above-described diffractive optical component 300, the hologram element 310 is sealed (sealed) by the supporting substrate SS in contact with the hologram element 310 from one side and the covering film member BFa in contact with the hologram element 310 from the opposite side, thereby suppressing or preventing moisture from entering the hologram element 310. In this case, the covering film member BFa is configured to have the connecting portion CN which is separated from the hologram element 310 and in contact with the supporting substrate SS. Thus, for example, at the connection portion CN, that is, the portion (interface) where the cover film member BFa contacts the support substrate SS, it is possible to avoid or suppress the intrusion of moisture into the hologram element 310 due to a capillary phenomenon or the like. Therefore, if the diffractive optical member 300 is applied to, for example, the HMD 200 as a virtual image display device, a good image can be formed in the HMD 200.

[0051] [Second embodiment]

[0052] Below, refer to Figure 6 An example of a diffractive optical component of the second embodiment is described. In this embodiment, the points other than the structure of the supporting substrate SS in the diffractive optical component 300 are the same as those of the first embodiment, and the application to the virtual image display device is also the same, so the same reference numerals as those of the first embodiment are applied, and the matters described in the first embodiment are referred to as needed. In addition, Figure 6 is with Figure 4 Corresponding longitudinal section view.

[0053] In the diffractive optical component 300 of the present embodiment, the supporting base material SS is composed of the first substrate member BM1 and does not have the supporting side film member BFb (see Figure 4 ) structure, which is different from the case of the first embodiment. That is, in this embodiment, the outermost layer of the first substrate member BM1 is in contact with the hologram element 310, the adhesive layer 340, and the cover film member BFa. Here, the support side dielectric film 331 (first dielectric film) as the outermost layer of the first substrate member BM1 is set as the dielectric film MD that becomes the outermost layer in contact with the hologram element 310 in the supporting base material SS. In this case, the cover film member BFa is in contact with the support side dielectric film 331 as the first dielectric film to form a connection portion CN.

[0054] In this case, it is necessary to ensure the close contact between the support-side dielectric film 331 and the cover film member BFa. In this embodiment, for example, the support-side dielectric film 331 and the support-side film member BFb (see Figure 4 ) Similarly, by selecting materials, etc., necessary and sufficient adhesion can be ensured between the support-side dielectric film 331 serving as the outermost layer and the covering film member BFa.

[0055] In this embodiment, the hologram element 310 is sealed (enclosed) by the support-side dielectric film 331 and the cover film member BFa, and the intrusion of moisture into the hologram element 310 is suppressed or prevented. In this case, the cover film member BFa has the connection portion CN separated from the hologram element 310 and in contact with the support-side dielectric film 331, thereby being able to avoid or suppress the intrusion of moisture into the hologram element 310 due to the capillary phenomenon, etc. Therefore, if the diffractive optical component 300 is applied to, for example, a virtual image display device, good image formation can be performed.

[0056] [Third embodiment]

[0057] Below, refer to Figure 7 An example of a diffractive optical component of the third embodiment is described. In this embodiment, the diffractive optical component 300 is different from the other embodiments described above in that it has an outer surface dielectric film 335 provided on the adhesive layer (adhesive member) 340, the supporting substrate SS, and the outer surface of the covering substrate CC (i.e., the outer surface of the adhesive layer 340, the first substrate 321, and the second substrate 322). Other points are the same as those of the first embodiment, and the application to the virtual image display device is also the same. Therefore, the same reference numerals as those of the first embodiment are applied, and as needed, reference is made to the matters described in the first embodiment. In addition, Figure 7 is with Figure 4 Here, the outer surface dielectric film 335 is also referred to as a third dielectric film.

[0058] The diffractive optical component 300 of this embodiment is different from the first embodiment etc. in that an outer surface dielectric film 335 (third dielectric film) is provided on the outer surfaces of the first substrate 321 and the second substrate 322. In particular, in the example shown in the figure, not only the first substrate 321 and the second substrate 322 are covered with the outer surface dielectric film 335, but also the entire stacked body sandwiched therebetween is covered with the outer surface dielectric film 335.

[0059] As for the outer surface dielectric film 335, for example, various films having light transmittance and water resistance (barrier property) can be considered, similarly to the covering film component BFa, the dielectric film DF, etc. That is, it is considered that a strip-shaped component, various inorganic materials, etc. can be used as the outer surface dielectric film 335. However, in the manufacturing process of the diffraction optical component 300, it is considered to provide the installation of the outer surface dielectric film 335 in a process after the process of clamping the hologram element 310 by the supporting substrate SS and the covering substrate CC. Therefore, it is considered that the following requirements may arise in manufacturing, for example: in order to avoid the degradation of the hologram element 310, it is possible to prevent it from being exposed to high temperature for a long time. Therefore, for example, it is considered to use a film formed by the method shown in Table 1 below or a laminated film as the outer surface dielectric film 335. In addition, in Figure 7 In the example shown, Figure 4 The illustrated structure is an example of applying an outer surface dielectric film 335, but is not limited to this. Figure 5 In the example shown, an outer surface dielectric film 335 or the like may be applied.

[0060]

Table 1

[0061]

[0062] In addition, the outer surface dielectric film 335 may also be given a function as an anti-reflection film (AR coating). From a different perspective, the anti-reflection film may also have a water resistance (water vapor barrier) function.

[0063] In this embodiment, the hologram element 310 is sealed (enclosed) by the supporting substrate SS and the cover film member BFa, and the intrusion of water into the hologram element 310 is suppressed or prevented. In this case, the cover film member BFa has a connection portion CN separated from the hologram element 310 and in contact with the supporting substrate SS, thereby avoiding or suppressing the intrusion of water into the hologram element 310 caused by the capillary phenomenon, etc. Therefore, if the diffractive optical component 300 is applied to a virtual image display device, for example, a good image formation can be performed. In addition, in the case of this embodiment, the intrusion of water into the inside of the diffractive optical component 300 can be further suppressed by the outer surface dielectric film 335.

[0064] 〔Modifications and other matters〕

[0065] The specific structures of the diffractive optical component 300 and the display device 100 and HMD 200 to which the diffractive optical component is applied described above are merely examples, and various modifications can be made within the scope of achieving the same function.

[0066] Figure 8 is another example of a ray diagram of an optical system in an HMD, which is similar to Figure 2In the illustrated optical system 610, Figure 2 Similarly, the illustrated optical system 10 includes, in addition to the image light generating device 31, a first optical section L10 having a positive refractive power, a second optical section L20 having a positive refractive power, a third optical section L30 having a positive refractive power, and a fourth optical section L40 having a positive refractive power. The first optical section L10 is composed of a projection optical system 632, the second optical section L20 is composed of a first diffractive optical component 650 which is a reflective diffractive element, the third optical section L30 is composed of a light guide system 660, and the fourth optical section L40 is composed of a second diffractive optical component 670 which is a reflective diffractive element. In addition, the light incident surfaces of the first diffractive optical component 650 and the second diffractive optical component 670 are shaped to be curved with the central portion being concave relative to the peripheral portion, and can be efficiently deflected toward the light guide system 660.

[0067] The projection optical system 632 is an optical system for projecting the image light IL generated by the image light generating device 31, and is composed of a plurality of lenses 632a. In addition, in the figure, the case where the lenses 632a in the projection optical system 32 are set to three pieces is listed, but the number of lenses 632a is not limited to this, and the projection optical system 632 may also have more than four lenses 632a. In addition, the lenses 632a may also be bonded together to form the projection optical system 632. In addition, the lenses 632a may also be composed of lenses with free-form surfaces.

[0068] The light guide system 660 includes a lens system 661 for incident image light IL emitted from the first diffractive optical component 650, and a reflector 662 for causing the image light IL emitted from the lens system 661 to be emitted in an inclined direction. The lens system 661 is composed of a plurality of lenses 661a. The reflector 662 has a reflective surface 662s inclined in the front-rear direction. The reflector 662 may be a total reflector, but the range in which external light can be seen may be expanded by making the reflector 662 a semi-transparent semi-reflective mirror.

[0069] In the above-described configuration, by using the diffractive optical member 300 having the above-described structure as the first diffractive optical member 650 and the second diffractive optical member 670 , a good image can be formed.

[0070] Although detailed illustrations are omitted, Figure 2 or Figure 8The optical system in another example of HMD that is partially modified from the optical system illustrated above may include a structure having an image light generating device 31, a scanning mirror, and a diffractive optical component 300. In this case, the light emitted by the image light generating device 31 is a semiconductor laser, which is a laser obtained by combining the lasers output from a red laser light source, a blue laser light source, and a green laser light source. Furthermore, by appropriately modulating the output from the laser light sources of each color, lasers of any color are output. Furthermore, by performing modulation in conjunction with the scanning mirror described later, etc., an image can be displayed on the retina of the user's eye.

[0071] The scanning mirror is a structure that reflects the laser light emitted from the image light generating device toward the diffractive optical component 300. In addition, the scanning mirror includes a mirror and a vibration control unit that controls the vibration of the mirror at a certain frequency, and the vibration control unit is composed of, for example, MEMS. In this way, by forming the vibration control unit with MEMS, the scanning mirror can be miniaturized.

[0072] The diffractive optical component 300 is used to display an image on the retina of the user's eye by deflecting (reflecting) the light emitted from the image light generating device 31 via the scanning mirror. By adopting such a configuration, the structure of the optical system in the HMD can be simplified.

[0073] In addition, various combinations of the above-described embodiments are possible. For example, when a plurality of diffractive optical components are provided in the HMD, diffractive optical components having different structures may be used in combination.

[0074] In addition, Figure 1 In the display device 100 shown, the horizontal direction (direction parallel to the XZ plane) is used as the main direction to guide the image light IL, but it is not limited to this. For example, this embodiment can also be applied when the vertical direction (direction parallel to the YZ plane) is used as the main direction to guide the image light IL.

[0075] Furthermore, for example, in each of the above-described embodiments, the display device 100 is incorporated in the HMD 200 , but the display device 100 may be incorporated in a head-up display.

[0076] Furthermore, the diffractive optical component 300 described as an example in the above-mentioned embodiments can be applied to various optical components or products using diffractive optical components other than HMDs and the like.

[0077] In addition, the display device 100 or the HMD 200 is not limited to a see-through type device that can observe an external image, and can also be applied to a closed type HMD that blocks an external image. In this case, for example Figure 3Of the supporting substrate SS and the cover substrate CC shown in the figure, the one through which the image light IL does not pass may be made of a non-transparent (opaque) material.

[0078] As described above, a diffractive optical component in a specific embodiment includes: a hologram element; a supporting substrate that contacts the hologram element from one side and supports the hologram element; and a first film component that contacts the hologram element from the side opposite to the one side and covers the hologram element, the first film component having a connecting portion that contacts the supporting substrate, and the connecting portion is separated from the hologram element.

[0079] In the above-mentioned diffractive optical component, the hologram element is sealed (enclosed) by the supporting substrate in contact with the hologram element from one side and the first film member in contact with the hologram element from the opposite side, thereby suppressing or preventing moisture from entering the hologram element. In this case, the covering film member is configured to have a connecting portion separated from the hologram element and in contact with the supporting substrate. Thus, for example, at the connecting portion, i.e., the portion (interface) where the first film member contacts the supporting substrate, it is possible to avoid or suppress the intrusion of moisture into the hologram element due to a capillary phenomenon, etc., and when the above-mentioned diffractive optical component is applied to, for example, a virtual image display device, a good image can be formed.

[0080] In a specific aspect, the supporting base has a first dielectric film in contact with the hologram element, and the first film member is in contact with the first dielectric film to form a connection portion. In this case, the hologram element can be sealed (enclosed) while being separated from the connection portion by the first film member and the first dielectric film.

[0081] In another aspect, the supporting base has a second film member in contact with the hologram element, and the first film member and the second film member are in contact with each other to form a connecting portion. In this case, the hologram element can be sealed (enclosed) while being separated from the connecting portion by the first film member and the second film member.

[0082] In another aspect, the supporting base material has a first dielectric film formed on a substrate, and the second film member is provided between the hologram element and the first dielectric film when viewed in the normal direction of a cross section including the hologram element, the supporting base material, and the first film member. In this case, close contact between the second film member and the hologram element and close contact between the second film member and the first dielectric film can be ensured, and intrusion of moisture into the hologram element can be avoided or suppressed.

[0083] In another aspect, the gas portion formed between the first film member, the holographic optical element, and the supporting substrate is filled with an inert gas by the connection at the connection portion. In this case, for example, generation of moisture in the gas portion due to an unexpected reaction can be avoided or suppressed.

[0084] In another aspect, a cover substrate is provided to cover the hologram element and the first film member. In this case, the cover substrate can protect the first film member and the hologram element.

[0085] In another aspect, there is an adhesive component for bonding the supporting substrate, the first film component and the covering substrate. In this case, the various parts can be bonded and fixed by the adhesive component. In addition, in this case, the convex step and gap difference caused by the stacking of the various parts can be absorbed in the adhesive component.

[0086] In another aspect, the cover substrate has a second dielectric film in contact with the adhesive member, and the adhesive member is provided between the first film member and the second dielectric film when viewed in the normal direction of a cross section including the holographic element, the supporting substrate, and the first film member. In this case, the first film member and the cover substrate can be reliably bonded and fixed.

[0087] In another aspect, a third dielectric film is provided which is in contact with the adhesive member and covers the supporting substrate and the covering substrate. In this case, the third dielectric film can further suppress or prevent moisture from entering the hologram element.

[0088] In another aspect, the first film member is a resin tape having a thickness of 10 μm or more. In this case, for example, when manufacturing a diffractive optical component, the first film member having sufficient water resistance and a desired shape at a desired position can be easily and reliably mounted.

[0089] In another aspect, the first film member is a light-transmitting tape. In this case, for example, it can be applied to a virtual image display device that needs to ensure the transparency of the diffractive optical member.

[0090] In another aspect, the connection portion forms a connection surface having a width of 2 mm or more and in contact with the supporting substrate. In this case, the sealed state of the connection portion can be reliably maintained.

[0091] As described above, a virtual image display device in a specific embodiment includes any of the above-mentioned diffractive optical components. In this case, by using the above-mentioned diffractive optical component, it is possible to avoid or suppress the infiltration of moisture into the hologram element used for image formation, and to perform good image formation.

[0092] In a specific aspect, the diffractive optical component is arranged in front of the eyes of the user when in use, the hologram element includes a first region including interference fringes and a second region not including interference fringes, and the second region is provided between the connecting portion and the first region when viewed in the normal direction of a cross section including the hologram element, the supporting substrate, and the first film member. In this case, by providing the second region, for example, the gas portion formed by maintaining a state of being separated from the connecting portion can be kept away from the eyes of the user, and the perspective can be maintained (secured) in a good state.

Claims

1. A diffractive optical component, wherein: The diffractive optical component has: Holographic elements; a supporting substrate which contacts the holographic element from one side and supports the holographic element; as well as a first film member which contacts the hologram element from the side opposite to the one side and covers the hologram element, The first film member has a connection portion in contact with the supporting substrate, The connecting portion is separated from the hologram element via a gas portion formed between the first film member, the hologram element, and the supporting substrate.

2. The diffractive optical component according to claim 1, wherein: The supporting substrate has a first dielectric film in contact with the holographic optical element. The first film member is in contact with the first dielectric film to form the connection portion.

3. The diffractive optical component according to claim 1, wherein: The supporting substrate has a second film member in contact with the holographic optical element. The first film member and the second film member are in contact with each other to form the connection portion.

4. The diffractive optical component according to claim 3, wherein: The supporting base material has a first dielectric film formed on a substrate. The second film member is provided between the hologram element and the first dielectric film when viewed in the normal direction of a cross section including the hologram element, the supporting substrate, and the first film member.

5. The diffractive optical component according to any one of claims 1 to 4, wherein: The gas portion is filled with an inert gas through the connection at the connection portion.

6. The diffractive optical component according to any one of claims 1 to 4, wherein: The diffractive optical member includes a cover substrate covering the hologram element and the first film member.

7. The diffractive optical component according to claim 6, wherein: The diffractive optical member includes an adhesive member for bonding the supporting substrate, the first film member, and the cover substrate.

8. The diffractive optical component according to claim 7, wherein: The cover substrate has a second dielectric film in contact with the adhesive member, The adhesive member is provided between the first film member and the second dielectric film when viewed in a normal direction of a cross section including the holographic optical element, the supporting substrate, and the first film member.

9. The diffractive optical component according to claim 7 or 8, wherein: The diffractive optical component includes a third dielectric film that is in contact with the adhesive member and covers the supporting substrate and the cover substrate.

10. The diffractive optical component according to any one of claims 1 to 4, wherein: The first film member is a resin tape having a thickness of 10 μm or more.

11. The diffractive optical component according to any one of claims 1 to 4, wherein: The first film member is a light-transmitting tape.

12. The diffractive optical component according to any one of claims 1 to 4, wherein: The connection portion forms a connection surface having a width of 2 mm or more and in contact with the support substrate.

13. A virtual image display device, wherein: This virtual image display device comprises the diffractive optical component according to any one of claims 1 to 12.

14. The virtual image display device according to claim 13, wherein: The diffractive optical component is arranged in front of the user's eyes when in use. The hologram element has a first region including interference fringes and a second region not including the interference fringes. When viewed in the normal direction of a cross section including the holographic optical element, the supporting substrate, and the first film member, the second region is provided between the connecting portion and the first region.

Images