Optical member, and ar glass and head-mounted display using the same

Abstract

To provide an optical member for AR (Augmented Reality) that is thin and lightweight, bright, and suppressible in light leakage.SOLUTION: An optical member according to an embodiment of the present invention comprises: an optical waveguide with first and second main surfaces; optical elements each that have a rugged structure provided on the at least one main surface of the first and second main surfaces of the optical waveguide; a porous layer that is provided on the main surface of the optical waveguide on which the optical elements are at least provided; and an adhesive layer that is provided on an opposite side surface of the porous layer to the optical waveguide and has a thickness of 3 μm or more.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical element and AR glasses and a head-mounted display using the optical element. [Background technology]

[0002] In recent years, so-called AR (Augmented Reality) technology has attracted attention. Typically, AR "virtually extends" the world before our eyes by overlaying virtual visual information onto real-world scenery. Along with the development of AR, the development of AR glasses and head-mounted displays (HMDs) used in AR is progressing. Typically, AR glasses and HMDs use optical components including waveguides. However, such optical components have problems such as being thick, heavy, and dark, as well as being prone to light leakage due to water or dirt, and various issues remain to be considered before practical application. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] U.S. Patent Application Publication No. 2017 / 0131545 [Patent Document 2] U.S. Patent Application Publication No. 2020 / 0379184 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] The present invention was made to solve the above-mentioned conventional problems, and its main objective is to provide an optical component for AR that is thin, lightweight, bright, and has suppressed light leakage. [Means for solving the problem]

[0005] An optical member according to an embodiment of the present invention comprises: an optical waveguide having a first main surface and a second main surface; an optical element having an uneven structure provided on at least one of the first main surface and the second main surface; a porous layer provided on at least the main surface of the optical waveguide on which the optical element is provided; and an adhesive layer having a thickness of 3 μm or more provided on the side of the porous layer opposite to the optical waveguide. In one embodiment, the refractive index of the porous layer is 1.20 or less. In one embodiment, the thickness of the porous layer is 5 μm or less. In one embodiment, the haze of the porous layer is less than 5%. In one embodiment, the storage modulus of the adhesive layer is 0.2 × 10⁻⁶. 5 (Pa) or higher. In one embodiment, the optical member further comprises a protective layer made of a resin film having a thickness of 20 μm or more on the outside of the adhesive layer. In one embodiment, the Young's modulus of the protective layer is 2 GPa or greater. In one embodiment, the optical member further has a hard coat layer on the outside of the protective layer. In one embodiment, the optical member further has an anti-reflective layer on the outside of the hard coat layer. According to another aspect of the present invention, AR glasses are provided, which include the optical elements described above. According to yet another aspect of the present invention, a head-mounted display is provided, which includes the optical elements described above. [Effects of the Invention]

[0006] According to embodiments of the present invention, it is possible to realize an optical component for augmented reality that is thin, lightweight, bright, and has suppressed light leakage. [Brief explanation of the drawing]

[0007] [Figure 1] This is a schematic cross-sectional view of an optical member according to one embodiment of the present invention. [Figure 2] This is a schematic cross-sectional view of an optical member according to another embodiment of the present invention. [Figure 3] This is a schematic cross-sectional view of an optical member according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0008] The embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. For clarity, the drawings are schematic representations, and the thickness, size, and relative ratios of the optical components shown in the drawings differ from those of actual components.

[0009] A. Overall configuration of optical components FIG. 1 is a schematic cross-sectional view of an optical member according to one embodiment of the present invention. The optical member 100 in the illustrated example includes an optical waveguide 10, optical elements 20a and 20b, a porous layer 30, and an adhesive layer 40. The optical waveguide 10 has a first main surface 10a and a second main surface 10b. The optical elements 20a and 20b each have a concavo-convex structure (hereinafter, the optical elements 20a and 20b may be referred to as concavo-convex optical elements, respectively). The concavo-convex optical element 20a typically functions as an incident optical element of the optical waveguide; the concavo-convex optical element 20b typically functions as an output optical element of the optical waveguide. The concavo-convex optical elements 20a and 20b are provided on at least one of the first main surface 10a and the second main surface 10b of the optical waveguide 10. The concavo-convex optical elements 20a and 20b may be provided on the same main surface of the optical waveguide, or may be provided on different main surfaces. In the illustrated example, the concavo-convex optical elements 20a and 20b are provided on the first main surface 10a of the optical waveguide 10. The porous layer 30 is provided on at least the main surface (the first main surface 10a in the illustrated example) of the optical waveguide 10 where the concavo-convex optical elements 20a and 20b are provided. The porous layer 30 is typically provided so as to cover the concavo-convex optical elements 20a and 20b, and in one embodiment, is provided substantially over the entire surface of the main surface (the first main surface 10a in the illustrated example) of the optical waveguide 10 where the concavo-convex optical elements 20a and 20b are provided. The adhesive layer 40 is provided on the side opposite to the optical waveguide 10 of the porous layer 30 (that is, the outer surface of the porous layer). The thickness of the adhesive layer is 3 μm or more. With such a configuration, it is possible to realize an AR optical member that is thin, lightweight, bright, and has suppressed light leakage.

[0010] If necessary, a protective layer 50, a hard coat layer 60, and / or an antireflection layer 70 may be provided on the outer side of the adhesive layer 40 (the side opposite to the porous layer 30). In the illustrated example, the protective layer 50, the hard coat layer 60, and the antireflection layer 70 are provided in this order from the adhesive layer 40 side. Depending on the purpose and desired configuration, at least one of the protective layer 50, the hard coat layer 60, and the antireflection layer 70 may be omitted. When the protective layer, the hard coat layer, and the antireflection layer are not provided, it is preferable that a release liner (not shown) is temporarily attached to the surface of the adhesive layer 40 until the optical member is used. By temporarily attaching the release liner, the adhesive layer is protected and the optical film can be formed into a roll.

[0011] FIG. 2 is a schematic cross-sectional view of an optical member according to another embodiment of the present invention. In the optical member 101 of the illustrated example, in addition to the main surface (the first main surface 10a in the illustrated example) provided with the concavo-convex optical elements 20a and 20b of the optical waveguide 10, the porous layer 30 and the adhesive layer 40 are also provided on the main surface (the second main surface 10b in the illustrated example) where no concavo-convex optical element is provided. In the illustrated example, protective layers 50, 50, hard coat layers 60, 60, and antireflection layers 70, 70 are provided in this order from the adhesive layer side outside the adhesive layers 40, 40. However, as in the embodiment of FIG. 1, some or all of these may be omitted.

[0012] FIG. 3 is a schematic cross-sectional view of an optical member according to yet another embodiment of the present invention. In the optical member 102 of the illustrated example, in addition to the first main surface 10a of the optical waveguide 10, the concavo-convex optical element 20b is also provided on the second main surface 10b. Otherwise, it is the same as the embodiment of FIG. 2.

[0013] The total light transmittance of the optical element is preferably 60% to 99%, more preferably 70% to 98%, and even more preferably 80% to 97%. The haze of the optical element is preferably 0.1% to 3%, more preferably 0.2% to 2.5%, and even more preferably 0.3% to 2%. According to the embodiments of the present invention, excellent transparency can be achieved for the optical element as a whole. As a result, the optical element can be suitably used in AR glasses and HMDs (hereinafter, AR glasses and HMDs may be collectively referred to as "AR glasses, etc.").

[0014] The thickness of the optical element is preferably 0.35 mm to 4.8 mm, more preferably 0.55 mm to 3.8 mm, and even more preferably 0.75 mm to 2.8 mm. According to embodiments of the present invention, since the optical element can be constructed without using a thick cover glass, the thickness can be reduced to about one-fifth compared to conventional optical elements for AR glasses that use a cover glass, and as a result, the weight can be reduced to about one-third. As a result, the optical element can be suitably used in AR glasses and the like. In this specification, "thickness of the optical element" means the total thickness from the outermost layer of one optical element to the outermost layer of the other. For example, in the embodiment of Figure 1, the thickness of the optical element is the thickness from the outer surface of the anti-reflective layer to the second main surface of the optical waveguide; and for example, in the embodiments of Figures 2 and 3, the thickness of the optical element is the thickness from the outer surface of one anti-reflective layer to the outer surface of the other anti-reflective layer.

[0015] The above embodiments may be combined or modified as appropriate. For example, in the embodiments shown in Figures 1 and 2, either the surface-relieving optical element 20a or 20b may be provided on the second main surface 10b of the optical waveguide; in the embodiment shown in Figure 3, the surface-relieving optical element 20a may be provided on the second main surface 10b of the optical waveguide; and in the embodiments shown in Figures 1 to 3, the surface-relieving optical element 20a may be provided on both the first main surface 10a and the second main surface 10b of the optical waveguide.

[0016] The components of the optical element will be described in detail below.

[0017] B. Optical waveguide The optical waveguide 10 is typically configured such that light incident on the optical waveguide propagates through the waveguide using total internal reflection and exits in a predetermined direction at a predetermined position. The optical waveguide 10 has a first main surface 10a and a second main surface 10b as described above. When the optical element is used in AR glasses or the like, light from an image source (not shown) (typically, projected image light) is incident on the optical waveguide through an incident optical element (a textured optical element 20a in the illustrated example) provided on the first main surface and / or the second main surface. The incident light propagates through the optical waveguide by total internal reflection and exits through an exit optical element (a textured optical element 20b in the illustrated example) provided on the first main surface and / or the second main surface, and is visible to the user of the AR glasses or the like. By appropriately configuring the textured optical elements 20a and 20b, light from the image source is emitted while maintaining image information. As a result, images from the image source can be seen by users of AR glasses or similar devices.

[0018] The optical waveguide may be made of glass or plastic. The refractive index of the optical waveguide is preferably 1.4 to 2.5, more preferably 1.6 to 2.4, and even more preferably 2.0 to 2.3. With a refractive index within this range, good external light incidence, good external light emission, and good total internal reflection within the optical waveguide can be achieved. The Abbe number of the optical waveguide is preferably 10 to 80, more preferably 15 to 70.

[0019] The total thickness variation (TTV) of the optical waveguide (first and second main surfaces) is preferably 5 μm or less, more preferably 3 μm or less, and even more preferably 1 μm or less. The smaller the thickness variation, the better, and it may even be zero. If the thickness variation of the optical waveguide is within this range, the distortion of the optical path within the optical waveguide can be reduced.

[0020] The surface roughness Ra of the optical waveguide (first and second main surfaces) is preferably 10 nm or less, more preferably 5 nm or less, and even more preferably 1 nm or less. A surface roughness Ra within this range allows for reduced haze. Such a surface roughness Ra can be achieved, for example, by polishing the first and second main surfaces of the optical waveguide. Alternatively, the surface roughness Ra may be, for example, 0.1 nm or more. Note that Ra refers to the arithmetic mean roughness based on JIS B 0601.

[0021] Optical waveguides may be used individually or in stacks of two or more (for example, two, three, or four). The thickness of the optical waveguide may be, for example, 0.3 mm to 4.0 mm. The thickness of the optical waveguide may also be, for example, 0.3 mm to 1.3 mm, or 0.4 mm to 1.2 mm, or 0.5 mm to 1.1 mm. Alternatively, the thickness of the optical waveguide may be, for example, 1.3 mm to 2.0 mm, or 1.4 mm to 1.9 mm, or 1.5 mm to 1.8 mm. Alternatively, the thickness of the optical waveguide may be, for example, 2.0 mm to 4.0 mm, or 2.2 mm to 3.8 mm, or 2.4 mm to 3.6 mm.

[0022] C. Optical elements The surface-concave optical element 20a is configured to guide light incident on the optical waveguide from the image source in the direction of the waveguide; the surface-concave optical element 20b is configured to emit light that has propagated within the optical waveguide in a direction that is visible. Hereinafter, surface-concave optical elements 20a and 20b may be collectively referred to simply as the surface-concave optical element. When it is necessary to distinguish between surface-concave optical element 20a and surface-concave optical element 20b, their respective symbols will be specified. However, even when surface-concave optical elements 20a and 20b are collectively referred to as the surface-concave optical element, surface-concave optical elements 20a and 20b may have the same configuration or may have different configurations.

[0023] The surface structure of a surface-concave optical element can employ any appropriate fine surface shape that can exhibit light direction conversion functions such as light diffusion, light scattering, light reflection, and light diffraction. Typical examples of surface-concave optical elements include diffraction gratings, holographic elements, and metasurfaces. Below, a diffraction grating will be described as an example.

[0024] Diffraction gratings typically have a diffraction pattern formed by grooves or slits. The diffraction pattern can be appropriately set according to the purpose. The diffraction pattern may be a one-dimensional diffraction pattern in the shape of stripes in a plan view, or a two-dimensional diffraction pattern in the shape of a grid in a plan view. In a one-dimensional diffraction pattern, typically, convex portions and slits extending in one direction are alternately formed. The cross-sectional shape of the convex portions, as viewed from the direction in which they extend, may be rectangular, parallelogram (inclined), or trapezoidal. The one-dimensional diffraction pattern may have a corrugated cross-sectional shape with convex and concave shapes extending in one direction. In a one-dimensional diffraction pattern, the direction in which the stripes extend may be parallel to the direction of optical guidance, perpendicular to the direction of optical guidance, or oblique to the direction of optical guidance at a predetermined angle. In a two-dimensional diffraction pattern, slits may be provided to form rectangular convex portions in a plan view, or slits may be provided to form parallelogram-shaped convex portions in a plan view. The above diffraction patterns may be combined as appropriate. For example, two one-dimensional diffraction patterns with stripes extending in different directions (for example, stripes extending in mutually orthogonal directions) may be combined, or three diffraction patterns such as these two one-dimensional diffraction patterns and a two-dimensional diffraction pattern may be combined.

[0025] The pitch Λ of the irregularities is preferably 30 nm to 700 nm, more preferably 40 nm to 600 nm, and even more preferably 50 nm to 500 nm. The width of the protrusions and slits (recesses) may be half the pitch, or they may not be half the pitch (each may have any appropriate width depending on the purpose). The height h of the irregularities is preferably 10 nm to 800 nm, more preferably 20 nm to 700 nm, even more preferably 30 nm to 600 nm, and particularly preferably 40 nm to 500 nm.

[0026] The surface-relieving optical element may be integrated with the optical waveguide or formed separately on the optical waveguide. When the surface-relieving optical element is integrated with the optical waveguide, it may be formed, for example, by cutting the optical waveguide; or, for example, in the case of a plastic optical waveguide, by nanoimprinting. When the surface-relieving optical element is formed separately on the optical waveguide, it may typically be composed of a dielectric or a resin. Specific examples of dielectrics include alumina, titania, and silicon. The refractive index of the dielectric is preferably 1.6 to 4.0, and more preferably 2.0 to 3.5. When the surface-relieving optical element is composed of a dielectric, it may be formed, for example, by sputtering. Specific examples of resins include thermosetting resins and UV-curable resins. The refractive index of such resins is preferably 1.5 to 1.9. When the surface-relieving optical element is composed of a resin, it may be formed, for example, by coating the resin as a thin film on the optical waveguide and then nanoimprinting. If the surface-convex optical element is a metasurface, it can be formed, for example, by the method described in the following document: "Supplementary Section 2. Details of experiments" in the Supplementary Information of "A broadband achromatic metalens in the visible" (Nature Nanotechnology volume 13, pages 227-232 (2018)).

[0027] D. Porous layer The porous layer 30 typically has voids inside. The porosity of the porous layer is preferably 35 volume% or more, more preferably 38 volume% or more, and particularly preferably 40 volume% or more. If the porosity is within this range, a porous layer with a particularly low refractive index can be formed. The upper limit of the porosity of the low refractive index layer is, for example, 90 volume% or less, and preferably 75 volume% or less. If the porosity is within this range, a porous layer with excellent strength can be formed. The porosity is a value calculated from the refractive index value measured with an ellipsometer using the Lorentz-Lorenz formula.

[0028] The refractive index of the porous layer is preferably 1.20 or less, more preferably 1.18 or less, even more preferably 1.16 or less, and particularly preferably 1.14 or less. On the other hand, the refractive index of the porous layer is preferably 1.05 or more, more preferably 1.08 or more, and even more preferably 1.10 or more. By providing a porous layer having such a refractive index on the main surface of the optical waveguide on which the uneven optical element is provided, light leakage can be suppressed without substantially affecting the optical properties of the optical waveguide and the uneven optical element. Furthermore, as described later, the porous layer can be made very thin, which can contribute to the thinning and weight reduction of the optical component (and consequently, the AR glasses). Also, if the refractive index of the porous layer is within the above range, a predetermined mechanical strength can be ensured, and breakage can be suppressed. Unless otherwise specified, the refractive index refers to the refractive index measured at a wavelength of 550 nm. The refractive index is the value measured by the method described in "(1) Refractive Index of Porous Layer" in the Examples described later.

[0029] The total light transmittance of the porous layer is preferably 85% to 99%, more preferably 87% to 98%, and even more preferably 89% to 97%. By providing a porous layer having such a refractive index on the main surface of the optical waveguide where the uneven optical element is provided, it is possible to achieve the above-mentioned effects of the refractive index while ensuring excellent transparency. As a result, the optical component can be suitably used in AR glasses and the like.

[0030] The haze of the porous layer is, for example, less than 5%, preferably less than 3%. On the other hand, the haze is, for example, 0.1% or more, preferably 0.2% or more. By providing a porous layer having such haze on the main surface of the optical waveguide where the uneven optical element is provided, it is possible to achieve the above-mentioned effect due to the refractive index while ensuring excellent transparency. As a result, the optical component can be suitably used in AR glasses and the like. The haze can be measured, for example, by the following method. The void layer (porous layer) is cut to a size of 50 mm x 50 mm and set in a haze meter (Murakami Color Technology Research Institute: HM-150) to measure the haze. The haze value is calculated using the following formula. Haze (%) = [Diffuse transmittance (%) / Total light transmittance (%)] × 100 (%)

[0031] The thickness of the porous layer is preferably 5 μm or less, more preferably 4 μm or less, even more preferably 3 μm or less, particularly preferably 2 μm or less, and especially preferably 1.5 μm or less. On the other hand, the thickness of the porous layer is preferably 300 nm or more, more preferably 400 nm or more, and even more preferably 500 nm or more. When the thickness of the porous layer is within this range, excellent transparency can be ensured while effectively suppressing light leakage.

[0032] Any suitable configuration can be adopted for the porous layer, as long as it has the desired properties described above. The porous layer can preferably be formed by coating or printing. As materials constituting the porous layer, for example, materials described in International Publication No. 2004 / 113966, Japanese Patent Publication No. 2013-254183, and Japanese Patent Publication No. 2012-189802 can be used. Representative examples include silicon compounds. Examples of silicon compounds include silica compounds; hydrolyzable silanes, and their partial hydrolysates and dehydration condensates; silicon compounds containing silanol groups; and activated silica obtained by contacting silicates with acids or ion exchange resins. Organic polymers; polymerizable monomers (e.g., (meth)acrylic monomers and styrene monomers); and curable resins (e.g., (meth)acrylic resins, fluorine-containing resins, and urethane resins) can also be used. These materials may be used individually or in combination. The porous layer can be formed by coating or printing a solution or dispersion of such materials.

[0033] In a porous layer, the size of the voids (pores) refers to the diameter of the major axis of the void (pore) compared to the diameter of the major axis. The size of the voids (pores) is, for example, 2 nm to 500 nm. The size of the voids (pores) is, for example, 2 nm or more, preferably 5 nm or more, more preferably 10 nm or more, and even more preferably 20 nm or more. On the other hand, the size of the voids (pores) is, for example, 500 nm or less, preferably 200 nm or less, and even more preferably 100 nm or less. The range of the void (pore) size is, for example, 2 nm to 500 nm, preferably 5 nm to 500 nm, more preferably 10 nm to 200 nm, and even more preferably 20 nm to 100 nm. The size of the voids (pores) can be adjusted to a desired size depending on the purpose and application. The size of the voids (pores) can be quantified by the BET test method.

[0034] The size of the voids (pores) can be quantified using the BET test method. Specifically, 0.1 g of the sample (formed void layer) is placed in the capillary of a specific surface area measuring device (Micromeritic: ASAP2020), and then dried under reduced pressure at room temperature for 24 hours to remove gas from within the void structure. Then, nitrogen gas is adsorbed onto the sample to create an adsorption isotherm, and the pore distribution is determined. This allows for the evaluation of the void size.

[0035] Examples of porous layers having voids inside include porous layers and / or porous layers having at least a portion of an air layer. The porous layer typically includes aerogel and / or particles (e.g., hollow fine particles and / or porous particles). The porous layer is preferably a nanoporous layer (specifically, with a diameter of 10 or more fine pores of 90% or more). -1 nm~10 3 It may be a porous layer within the range of nm.

[0036] Any suitable particles can be used as the above-mentioned particles. Typically, the particles consist of silica-based compounds. Examples of particle shapes include spherical, plate-shaped, needle-shaped, string-shaped, and grape cluster-shaped. Examples of string-shaped particles include particles in which multiple spherical, plate-shaped, or needle-shaped particles are linked together in a chain-like manner, short fibrous particles (for example, short fibrous particles described in Japanese Patent Publication No. 2001-188104), and combinations thereof. String-shaped particles may be linear or branched. Examples of grape cluster-shaped particles include those formed by the aggregation of multiple spherical, plate-shaped, and needle-shaped particles to form a grape cluster. The shape of the particles can be confirmed, for example, by observation with a transmission electron microscope.

[0037] The following describes an example of the specific structure of a porous layer. The porous layer in this embodiment consists of one or more types of constituent units that form a fine void structure, and these constituent units are chemically bonded to each other via catalytic action. Examples of the shapes of the constituent units include particulate, fibrous, rod-shaped, and plate-shaped. The constituent units may have only one shape, or they may have a combination of two or more shapes. In the following, we will mainly describe the case in which the porous layer is a void layer of a porous material in which the fine pore particles are chemically bonded to each other.

[0038] Such void layers can be formed in the void layer formation process, for example, by chemically bonding microporous particles together. In embodiments of the present invention, the shape of the "particles" (e.g., the above-mentioned microporous particles) is not particularly limited and may be spherical or of other shapes. In embodiments of the present invention, the above-mentioned microporous particles may be, for example, sol-gel bead-like particles, nanoparticles (hollow nanosilica / nanoballoon particles), nanofibers, etc. Microporous particles typically include inorganic substances. Specific examples of inorganic substances include silicon (Si), magnesium (Mg), aluminum (Al), titanium (Ti), zinc (Zn), and zirconium (Zr). These may be used individually or in combination of two or more. In one embodiment, the above-mentioned microporous particles are, for example, microporous particles of a silicon compound, and the above-mentioned porous body is, for example, a silicone porous body. The above-mentioned microporous particles of a silicon compound include, for example, a pulverized gel-like silica compound. Furthermore, another form of a porous layer having at least a porous layer and / or an air layer is a void layer made of fibrous material such as nanofibers, in which the fibrous material is intertwined to form voids and create a layer. The method for manufacturing such a void layer is not particularly limited and is similar to that of a void layer of a porous material in which the fine porous particles are chemically bonded together. Further other forms include void layers using hollow nanoparticles or nanoclay, and void layers formed using hollow nanoballoons or magnesium fluoride. The void layer may be made of a single constituent material or of multiple constituent materials. The void layer may consist of a single of the above forms or may include multiple of the above forms.

[0039] In this embodiment, the porous structure of the porous body may be, for example, a continuous cell structure in which the pore structure is continuous. A continuous cell structure means, for example, in the above-mentioned porous silicone body, that the pore structure is connected in three dimensions, and can also be described as a state in which the internal voids of the pore structure are continuous. By having a continuous cell structure in the porous body, it is possible to increase the porosity. However, when using closed-cell particles (particles that each have a pore structure) such as hollow silica, a continuous cell structure cannot be formed. On the other hand, when using silica sol particles (pulverized gel-like silicon compounds that form a sol), for example, because the particles have a three-dimensional dendritic structure, it is possible to easily form a continuous cell structure by the sedimentation and accumulation of the dendritic particles in the coating film (a coating film of a sol containing the pulverized gel-like silicon compounds). The porous layer more preferably has a monolithic structure in which the continuous cell structure includes a plurality of pore distributions. A monolithic structure means, for example, a hierarchical structure that includes a structure in which nano-sized fine voids exist and a continuous cell structure in which these nano-voids are aggregated. When forming a monolithic structure, for example, it is possible to achieve both film strength and high porosity by providing fine voids while simultaneously providing high porosity with coarse, interconnected voids. Such a monolithic structure can preferably be formed by controlling the pore distribution of the resulting void structure in the gel (gel-like silicon compound) prior to grinding it into silica sol particles. Alternatively, for example, when grinding a gel-like silicon compound, a monolithic structure can be formed by controlling the particle size distribution of the resulting silica sol particles to a desired size.

[0040] The porous layer contains, for example, pulverized gel-like compounds as described above, and these pulverized particles are chemically bonded to each other. The form of chemical bonding between the pulverized particles in the porous layer is not particularly limited and includes, for example, cross-linking, covalent bonding, and hydrogen bonding.

[0041] The volume-average particle diameter of the pulverized material in the porous layer is, for example, 0.10 μm or more, preferably 0.20 μm or more, and more preferably 0.40 μm or more. On the other hand, the volume-average particle diameter is, for example, 2.00 μm or less, preferably 1.50 μm or less, and more preferably 1.00 μm or less. The range of the volume-average particle diameter is, for example, 0.10 μm to 2.00 μm, preferably 0.20 μm to 1.50 μm, and more preferably 0.40 μm to 1.00 μm. The particle size distribution can be measured, for example, by particle size distribution evaluation devices such as dynamic light scattering and laser diffraction, and by electron microscopes such as scanning electron microscopes (SEM) and transmission electron microscopes (TEM). Note that the volume-average particle diameter is an indicator of the variation in particle size of the pulverized material.

[0042] The type of gel-like compound is not particularly limited. Examples of gel-like compounds include gel-like silicon compounds.

[0043] Furthermore, in the porous layer (void layer), it is preferable that the silicon atoms contained are bonded together by siloxane bonds. Specifically, the proportion of unbonded silicon atoms (i.e., residual silanols) among the total silicon atoms contained in the void layer is, for example, less than 50%, preferably 30% or less, and more preferably 15% or less.

[0044] The following describes an example of a method for forming such a porous layer.

[0045] The method typically includes a precursor formation step of forming a void structure, which is a precursor of a porous layer (void layer), on an optical waveguide, and a crosslinking reaction step of causing a crosslinking reaction within the precursor after the precursor formation step. The method further includes a containing liquid preparation step of preparing a containing liquid containing microporous particles (hereinafter sometimes referred to as "microporous particle containing liquid" or simply "containing liquid"), and a drying step of drying the containing liquid, wherein the precursor formation step chemically bonds the microporous particles in the dried body to form the precursor. The containing liquid is not particularly limited and is, for example, a suspension containing microporous particles. In the following, the case in which the microporous particles are pulverized gel-like compounds and the void layer is a porous body (preferably a silicone porous body) containing pulverized gel-like compounds will be mainly described. However, the porous layer can be formed similarly even when the microporous particles are not pulverized gel-like compounds.

[0046] According to the method described above, for example, a porous layer (void layer) with a very low refractive index is formed. The reason for this is presumed to be as follows. However, this presumption does not limit the method of forming the porous layer.

[0047] Since the above-mentioned pulverized material is obtained by pulverizing a gel-like silicon compound, the three-dimensional structure of the gel-like silicon compound before pulverization is dispersed within the three-dimensional basic structure. Furthermore, in the above method, by coating the crushed gel-like silicon compound onto a resin film, a precursor of a porous structure based on the three-dimensional basic structure is formed. In other words, according to the above method, a new porous structure (three-dimensional basic structure) is formed by coating with the pulverized material, which is different from the three-dimensional structure of the gel-like silicon compound. Therefore, in the void layer obtained in the end, a low refractive index that functions to the same extent as, for example, an air layer can be achieved. Moreover, in the above method, the three-dimensional basic structure is fixed because the pulverized materials are chemically bonded together. Therefore, the void layer obtained in the end can maintain sufficient strength and flexibility despite having a void structure.

[0048] Details of the specific configuration and formation method of the porous layer are described, for example, in International Publication No. 2019 / 151073. The description of this publication is incorporated herein by reference.

[0049] E. Adhesive Layer The adhesive layer 40 has a hardness such that the adhesive constituting the adhesive layer does not penetrate into the voids of the porous layer in a normal state. Therefore, the storage elastic modulus of the adhesive layer at 23°C is preferably 0.2×10 5 (Pa) or more, more preferably 0.4×10 5 (Pa) or more, still more preferably 0.6×10 5 (Pa) or more, particularly preferably 0.8×10 5 (Pa) or more, especially preferably 1.0×10 5 (Pa) or more. On the other hand, considering the durability of the adhesive layer, the storage elastic modulus of the adhesive layer at 23°C is preferably 5.0×10 7 (Pa) or less, more preferably 4.0×10 7 (Pa) or less, still more preferably 3.0×10 7 (Pa) or less, particularly preferably 2.0×10 7 (Pa) or less, especially preferably 1.0×10 7 (Pa) or less. Also, for example, the storage elastic modulus of the adhesive layer at 23°C may be 1.0×10 6 (Pa) or less. Such an adhesive layer has a buffering function (cushion function) against external forces and has a softness that can suppress damage to the porous layer. The storage elastic modulus is determined by reading the value at 23°C when measured in accordance with the method described in JIS K 7244-1 "Plastics - Test Methods for Dynamic Mechanical Properties" under the condition of a frequency of 1 Hz and a temperature increase rate of 5°C / min in the range of -50°C to 150°C.

[0050] Any suitable adhesive can be used as the adhesive constituting the adhesive layer, as long as it has the characteristics described above. Typical adhesives include acrylic adhesives (acrylic adhesive compositions). Typical acrylic adhesive compositions contain (meth)acrylic polymers as the main component (base polymer). (Meth)acrylic polymers may be contained in the adhesive composition in a proportion of, for example, 50% or more by weight, preferably 70% or more by weight, and more preferably 90% or more by weight, of the solid content of the adhesive composition. (Meth)acrylic polymers contain alkyl (meth)acrylate as the main component as monomer units. (Meth)acrylate refers to acrylate and / or methacrylate. Examples of alkyl groups in alkyl (meth)acrylate include linear or branched alkyl groups having 1 to 18 carbon atoms. The average number of carbon atoms in the alkyl group is preferably 3 to 9. Examples of monomers constituting (meth)acrylic polymers include alkyl (meth)acrylates, as well as comonomers such as carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, aromatic ring-containing (meth)acrylates, and heterocyclic (meth)acrylates. The comonomers are preferably hydroxyl group-containing monomers and / or heterocyclic (meth)acrylates, and more preferably N-acryloylmorpholine. The acrylic adhesive composition may preferably contain a silane coupling agent and / or a crosslinking agent. Examples of silane coupling agents include epoxy group-containing silane coupling agents. Examples of crosslinking agents include isocyanate-based crosslinking agents and peroxide-based crosslinking agents. Details of such adhesive layers or acrylic adhesive compositions are described, for example, in Japanese Patent No. 4140736, and the contents of said patent publication are incorporated herein by reference.

[0051] The thickness of the adhesive layer is 3 μm or more, preferably 10 μm or more, more preferably 25 μm or more, even more preferably 30 μm or more, and particularly preferably 40 μm or more. If the thickness of the adhesive layer is within this range, damage to the porous layer can be well suppressed, and as a result, the optical properties of the optical waveguide and the uneven optical element can be well maintained, and light leakage can be well suppressed. The above effect can be obtained if the thickness of the adhesive layer is 15 μm or more, so there is no upper limit on the thickness. However, from the viewpoint of thinning and weight reduction and cost, the thickness of the adhesive layer may be, for example, 200 μm or less, for example, 150 μm or less, or for example, 120 μm or less.

[0052] F. Protective layer The thickness of the protective layer 50 is preferably 20 μm or more, more preferably 25 μm or more, and even more preferably 30 μm or more. On the other hand, the thickness of the protective layer is preferably 200 μm or less, more preferably 150 μm or less, and even more preferably 120 μm or less. When the thickness of the protective layer is within this range, when the optical component is applied to AR glasses or the like, it is possible to provide excellent surface protection performance and suppress damage to the porous layer.

[0053] The Young's modulus of the protective layer 50 is preferably 2 GPa or more, more preferably 2.5 GPa or more, and even more preferably 3 GPa or more. On the other hand, the Young's modulus of the protective layer is preferably 10 GPa or less, more preferably 9 GPa or less, and even more preferably 8 GPa or less. When the Young's modulus of the protective layer is within this range, when the optical component is applied to AR glasses or the like, it is possible to provide excellent surface protection performance and suppress damage to the porous layer.

[0054] The protective layer 50 is composed of any suitable resin film. Examples of resin film forming materials include (meth)acrylic resins, cellulose resins such as diacetylcellulose and triacetylcellulose, cycloolefin resins such as norbornene resins, olefin resins such as polypropylene, ester resins such as polyethylene terephthalate resins, polyamide resins, polycarbonate resins, and copolymer resins thereof. Note that "(meth)acrylic resin" refers to acrylic resins and / or methacrylic resins.

[0055] The moisture permeability of the protective layer 50 is preferably 0.1 g / m². 2 / 24hr~1000g / m 2 It is / 24hr, and more preferably 0.5g / m² 2 / 24hr~800g / m 2 It is / 24hr, and more preferably 1g / m³ 2 / 24hr~500g / m 2 This is / 24hr. If the moisture permeability of the protective layer is within this range, damage to the porous layer can be further suppressed.

[0056] G. Hard coat layer The hard coat layer 60 preferably has a pencil hardness of H or higher, more preferably 2H or higher, and even more preferably 3H or higher. On the other hand, the pencil hardness of the hard coat layer is preferably 6H or lower, and more preferably 5H or lower. If the pencil hardness of the hard coat layer is within this range, when the optical component is applied to AR glasses or the like, it can provide excellent surface protection performance and suppress damage to the porous layer. The pencil hardness can be measured based on the "pencil hardness test" of JIS K 5400.

[0057] The thickness of the hard coat layer may be, for example, 0.5 μm to 30 μm, or for example, 1 μm to 20 μm, or for example, 2 μm to 15 μm. When the thickness of the hard coat layer is within this range, when the optical component is applied to AR glasses or the like, it is possible to provide excellent surface protection performance and suppress damage to the porous layer.

[0058] The hard coat layer can be composed of any suitable material, as long as it satisfies the above-mentioned properties. The hard coat layer is, for example, a cured layer of a thermosetting resin or an ionizing radiation (e.g., visible light, ultraviolet) curable resin. The hard coat layer may be, for example, a cured layer of a thermosetting resin or an ionizing radiation (e.g., visible light, ultraviolet) curable resin. Ultraviolet curable resins are preferred because they allow for easy and highly efficient formation of the hard coat layer. Specific examples of ultraviolet curable resins include polyester-based, (meth)acrylic-based, urethane-based, amide-based, silicone-based, epoxy-based, and unsaturated polyester-based ultraviolet curable resins. (Meth)acrylic ultraviolet curable resins include urethane (meth)acrylate, polyester (meth)acrylate, and epoxy (meth)acrylate. Ultraviolet curable resins may include ultraviolet curable monomers, oligomers, and polymers. Preferred ultraviolet curable resins include resin compositions containing acrylic monomer components or oligomer components having preferably two or more, more preferably three to six, ultraviolet polymerizable functional groups. Typically, UV-curing resins contain photopolymerization initiators.

[0059] The hard coat layer can be formed by any suitable method. Preferably, the hard coat layer can be formed by applying a hard coat layer forming resin composition onto the protective layer, drying it, and curing the dried coating film by irradiating it with ultraviolet light.

[0060] Details of the hard coat layer are described, for example, in Japanese Patent Publication No. 2011-237789 and Japanese Patent Publication No. 2016-224443. The descriptions in those publications are incorporated herein by reference.

[0061] H.Anti-reflection layer Any suitable configuration can be adopted for the anti-reflective layer 70. Typical configurations of the anti-reflective layer include: (1) a single layer of low refractive index layer with an optical film thickness of 120 nm to 140 nm and a refractive index of about 1.35 to 1.55; (2) a laminate having a medium refractive index layer, a high refractive index layer, and a low refractive index layer in order from the optical waveguide side; and (3) an alternating multilayer laminate of high refractive index layers and low refractive index layers.

[0062] Examples of materials that can form a low refractive index layer include silicon dioxide (SiO2) and magnesium fluoride (MgF2). The refractive index of the low refractive index layer is typically around 1.35 to 1.55. Examples of materials that can form a high refractive index layer include titanium dioxide (TiO2), niobium oxide (Nb2O3 or Nb2O5), tin-doped indium oxide (ITO), antimond-doped tin oxide (ATO), and ZrO2-TiO2. The refractive index of the high refractive index layer is typically around 1.60 to 2.20. Examples of materials that can form a medium refractive index layer include titanium dioxide (TiO2) and mixtures of materials that can form a low refractive index layer and materials that can form a high refractive index layer (for example, a mixture of titanium dioxide and silicon dioxide). The refractive index of the medium refractive index layer is typically around 1.50 to 1.85. The thicknesses of the low refractive index layer, the medium refractive index layer, and the high refractive index layer can be set to achieve an appropriate optical film thickness according to the layer structure of the anti-reflective layer, the desired anti-reflective performance, etc.

[0063] The anti-reflective layer described above is typically formed by a dry process. Specific examples of dry processes include PVD (Physical Vapor Deposition) and CVD (Chemical Vapor Deposition). PVD methods include vacuum deposition, reactive deposition, ion beam assisted deposition, sputtering, and ion plating. CVD methods include plasma CVD. Sputtering is preferred because it allows for more uniform film formation with less film thickness variation.

[0064] The thickness of the anti-reflective layer mentioned above is, for example, about 20 nm to 300 nm.

[0065] The anti-reflective layer 70 may be a cured layer of an ionizing radiation-curable resin composition. The ionizing radiation-curable resin composition includes an ionizing radiation-curable resin. Typical examples of ionizing radiation-curable resins include thermosetting resins, ultraviolet-curable resins, photocurable (visible light) resins, and electron beam-curable resins. For example, examples of ionizing radiation-curable resins include silicone resins, polyester resins, polyether resins, epoxy resins, urethane resins, alkyd resins, spiroacetal resins, polybutadiene resins, and polythiol polyene resins. For example, an ionizing radiation-curable resin may be a curable compound having acrylate groups and / or methacrylate groups that harden by heat, light (ultraviolet rays, etc.) or electron beams, etc. Specific examples include oligomers or prepolymers such as acrylates and / or methacrylates of polyfunctional compounds such as polyhydric alcohols. The ionizing radiation-curable resin may be used alone or in combination of two or more types. The ionizing radiation-curable resin composition may further contain a reactive diluent, a fluorine-containing additive, hollow particles, and / or solid particles, depending on the purpose. The anti-reflective layer of this embodiment can typically be formed by the following manufacturing method: applying an anti-reflective layer forming coating solution obtained by diluting the ionizing radiation-curable resin composition with a diluent; drying the coating film; and curing the dried coating film. The thickness of the anti-reflective layer of this embodiment may be, for example, 0.1 μm to 50 μm, or for example, 0.3 μm to 40 μm, or for example, 0.5 μm to 30 μm, or for example, 1.0 μm to 20 μm, or for example, 2.0 μm to 10 μm. [Examples]

[0066] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. The measurement methods for each characteristic are as follows. Unless otherwise specified, "%" and "parts" in the examples are based on weight.

[0067] (1) Refractive index of porous layer After forming a porous layer on the optical waveguide, it was cut to a size of 50 mm x 50 mm and bonded to the surface of a glass plate (thickness: 3 mm) via an adhesive layer. The center of the back surface of the glass plate (approximately 20 mm in diameter) was colored black with a marker to create a sample that did not reflect light from the back surface of the glass plate. The sample was set in an ellipsometer (JAWoollam Japan: VASE) and the refractive index was measured under conditions of a wavelength of 550 nm and an incident angle of 50 to 80 degrees.

[0068] (2) Optical waveguide protection (2-1) Pencil hardness Aside from setting the applied weight to 500g, the measurements were based on the "pencil hardness test" of JIS K 5400. (2-2) Image blur A predetermined image was incident on and emitted through the optical components obtained in the examples and comparative examples, and the emitted image was observed visually. The observed image was compared with the emitted image from the optical waveguide alone in Reference Example 1 and evaluated according to the following criteria. ○(Good): No whitishness was observed. × (Defective): A whitish appearance was observed. (2-3) Surface contamination resistance With 0.1 ml of water droplets placed on the surface of the optical components obtained in the examples and comparative examples, the emitted images were visually observed in the same manner as in (2-2) and evaluated according to the following criteria. ○ (Good): No image distortion or light leakage was observed. × (Defective): Image distortion and / or light leakage were observed.

[0069] [Manufacturing Example 1] Preparation of coating liquid for forming a porous layer (1) Gelation of silicon compounds Mixture A was prepared by dissolving 0.95 g of methyltrimethoxysilane (MTMS), a precursor of silicon compounds, in 2.2 g of dimethyl sulfoxide (DMSO). To this mixture A, 0.5 g of 0.01 mol / L aqueous oxalic acid solution was added, and the mixture was stirred at room temperature for 30 minutes to hydrolyze the MTMS and produce mixture B containing tris(hydroxy)methylsilane. To 5.5 g of DMSO, 0.38 g of 28% by weight aqueous ammonia and 0.2 g of pure water were added. Then, the above mixture B was added, and the mixture was stirred at room temperature for 15 minutes to gel tris(hydroxy)methylsilane, obtaining mixture C containing a gel-like silicon compound. (2) Aging process The mixed solution C containing the gel-like silicon compound prepared as described above was incubated at 40°C for 20 hours to perform the maturation process. (3) Grinding Next, the gel-like silicon compound, which had been aged as described above, was crushed into granules of several mm to several cm in size using a spatula. Then, 40 g of isopropyl alcohol (IPA) was added to mixture C, and after light stirring, it was left to stand at room temperature for 6 hours to decantate the solvent and catalyst in the gel. By performing the same decantation treatment three times, the solvent was replaced to obtain mixture D. Next, the gel-like silicon compound in mixture D was subjected to pulverization (high-pressure medialess pulverization). For the pulverization (high-pressure medialess pulverization), a homogenizer (manufactured by SMT Co., Ltd., product name "UH-50") was used, and 1.85 g of the gel-like compound and 1.15 g of IPA from mixture D were weighed into a 5 cc screw bottle, and pulverization was performed at 50 W, 20 kHz for 2 minutes. This grinding process pulverized the gel-like silicon compound in the above-mentioned mixture D, resulting in the mixture D becoming a sol E of the pulverized material. The volume-average particle size, which indicates the particle size variation of the pulverized material contained in sol E, was confirmed using a dynamic light scattering nanotrack particle size analyzer (Nikkiso Co., Ltd., UPA-EX150 model) and was found to be between 0.50 and 0.70. Furthermore, to 0.75 g of sol E, 0.062 g of a 1.5 wt% MEK (methyl ethyl ketone) solution of a photobase generator (Wako Pure Chemical Industries, Ltd.: product name WPBG266) and 0.036 g of a 5% MEK solution of bis(trimethoxysilyl)ethane were added in a ratio to obtain a coating liquid for forming a porous layer.

[0070] [Manufacturing Example 2] Preparation of the adhesive constituting the adhesive layer In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 90.7 parts butyl acrylate, 6 parts N-acryloylmorpholine, 3 parts acrylic acid, 0.3 parts 2-hydroxybutyl acrylate, and 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were charged together with 100 g of ethyl acetate. After introducing nitrogen gas and purging the mixture with nitrogen while gently stirring, the polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55°C to prepare an acrylic polymer solution. An acrylic adhesive solution was prepared by adding 0.2 parts isocyanate crosslinking agent (Coronate L, manufactured by Nippon Polyurethane Industries, Ltd., an adduct of trimethylolpropane tolylene diisocyanate), 0.3 parts benzoyl peroxide (Nippon Oil & Fats Co., Ltd., Niper BMT), and 0.2 parts γ-glycidoxypropyl methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: KBM-403) to 100 parts of the solids of the obtained acrylic polymer solution. Next, the above acrylic adhesive solution was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Films Co., Ltd., thickness: 38 μm) so that the thickness of the adhesive layer after drying would be 20 μm. The film was then dried at 150°C for 3 minutes to form the adhesive layer. The storage modulus of the obtained adhesive was 1.0 × 10⁻⁶. 5 It was (Pa).

[0071] [Example 1] An optical waveguide was extracted from commercially available AR glasses (Vuzix, product name "M4000"). The thickness of the optical waveguide was 1.05 mm. Furthermore, a diffraction grating (concave and convex optical element) was formed on the optical waveguide. The porous layer forming coating liquid prepared in Manufacturing Example 1 was applied to both sides of this optical waveguide. The coating film was dried by treating it at a temperature of 100°C for 1 minute to form a porous layer (thickness 1.2 μm). The porosity of the obtained porous layer was 60 volume%, and the refractive index was 1.18. Next, an adhesive layer (thickness 10 μm, storage modulus 1.3 × 10⁻⁶) formed in Manufacturing Example 2 was applied to the surface of each porous layer. 5The Pa) was transferred. Furthermore, a PET film (manufactured by Mitsubishi Chemical Polyester Films, 50 μm thick, elastic modulus 4.0 GPa) was laminated as a protective layer on the surface of each adhesive layer. Optical components were fabricated in this manner. The obtained optical components were subjected to the above evaluation. The results are shown in Table 1.

[0072] [Example 2] Optical components were fabricated in the same manner as in Example 1, except that triacetylcellulose (TAC) film (80 μm thick, elastic modulus 3.0 GPa) was used instead of PET film as the protective layer for each component. The obtained optical components were subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0073] [Comparative Example 1] An optical component was fabricated in the same manner as in Example 1, except that an adhesive layer and a protective layer were not formed. The obtained optical component was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0074] [Comparative Example 2] An optical component was fabricated in the same manner as in Example 1, except that a porous layer was not formed. The obtained optical component was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0075] [Reference example 1] The optical waveguide itself was subjected to the same evaluation as in Example 1 as an optical component. The results are shown in Table 1.

[0076] [Examples 3-7] An optical component was fabricated in the same manner as in Example 1, except that the thickness of the adhesive layer, the thickness of the protective layer, and the Young's modulus of the protective layer were changed as shown in Table 1. The obtained optical component was subjected to the same evaluation as in Example 1. The results are shown in Table 1.

[0077] [Table 1]

[0078] As is clear from Table 1, according to the embodiments of the present invention, an optical component can be obtained that suppresses surface contamination and produces an output image with reduced white blur and light leakage. Furthermore, the optical component of the embodiments has a total thickness of approximately 1.2 mm, achieving remarkable thinning (and consequently, remarkable weight reduction). [Industrial applicability]

[0079] Optical components according to embodiments of the present invention can be suitably used in AR glasses and HMDs. [Explanation of Symbols]

[0080] 10 Optical waveguide 10a First main surface 10b Second main surface 20a Concave and Convex Optical Element 20b Concave-convex optical elements 30 Porous layer 40 Adhesive layer 50 protective layer 60 Hard court layer 70 Anti-reflection layer 100 Optical components 101 Optical components 102 Optical components

Claims

1. an optical waveguide having a first major surface and a second major surface; an optical element having a concave-convex structure provided on at least one of the first main surface and the second main surface; a porous layer provided on at least the main surface of the optical waveguide on which the optical element is provided; a pressure-sensitive adhesive layer having a thickness of 3 μm or more provided on the porous layer on the side opposite to the optical waveguide; An optical member comprising:

2. 2. The optical member according to claim 1, wherein the porous layer has a refractive index of 1.20 or less.

3. The optical member according to claim 2 , wherein the porous layer has a thickness of 5 μm or less.

4. The optical member according to claim 3 , wherein the haze of the porous layer is less than 5%.

5. The pressure-sensitive adhesive layer has a storage modulus of 0.2×10 ５ The optical element according to claim 1 , wherein the surface roughness is 100% or more.

6. The optical member according to claim 1 , further comprising a protective layer formed on the outer side of the pressure-sensitive adhesive layer and made of a resin film having a thickness of 20 μm or more.

7. The optical member according to claim 6 , wherein the protective layer has a Young's modulus of 2 GPa or more.

8. The optical member according to claim 7 , further comprising a hard coat layer on the outer side of the protective layer.

9. The optical member according to claim 8 , further comprising an anti-reflection layer on the outside of the hard coat layer.

10. 10. AR glasses comprising the optical element according to claim 1.

11. A head-mounted display comprising the optical member according to claim 1 .

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