WO2023042798A1 - Plaque de diffuseur, dispositif d'affichage, dispositif de projection et dispositif d'éclairage - Google Patents

Plaque de diffuseur, dispositif d'affichage, dispositif de projection et dispositif d'éclairage Download PDF

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Publication number
WO2023042798A1
WO2023042798A1 PCT/JP2022/034068 JP2022034068W WO2023042798A1 WO 2023042798 A1 WO2023042798 A1 WO 2023042798A1 JP 2022034068 W JP2022034068 W JP 2022034068W WO 2023042798 A1 WO2023042798 A1 WO 2023042798A1
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Prior art keywords
microlens
microlenses
shape
diffusion plate
optical axis
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PCT/JP2022/034068
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English (en)
Japanese (ja)
Inventor
光雄 有馬
正之 石渡
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デクセリアルズ株式会社
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Publication of WO2023042798A1 publication Critical patent/WO2023042798A1/fr

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F21V5/04—Refractors for light sources of lens shape
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F21—LIGHTING
    • F21V—FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
    • F21V5/00—Refractors for light sources
    • F21V5/08—Refractors for light sources producing an asymmetric light distribution
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B3/00—Simple or compound lenses
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor

Definitions

  • the present invention relates to a diffusion plate, a display device, a projection device and a lighting device.
  • a diffusion plate that diffuses incident light in a desired direction is used to change the diffusion characteristics of light.
  • Diffusion plates are widely used in various devices such as display devices such as displays, projection devices such as projectors, and various lighting devices.
  • a microlens array type diffuser plate in which a plurality of microlenses each having a size of about several tens of micrometers is arranged is known.
  • Patent Document 1 discloses randomly arranging a plurality of microlenses using a honeycomb structure as a basic pattern.
  • a plurality of microlenses are randomly arranged on the surface of a diffusion plate so that the surface vertex position of each microlens is positioned within a predetermined circle centering on the surface vertex position in the basic pattern. ing.
  • the optical axis of the individual microlenses all extend in a direction (normal direction: Z direction) perpendicular to the surface of the diffuser plate. Therefore, the direction of the principal ray of the emitted light (diffused light) diffused by the diffusion plate is parallel to the direction of the principal ray of the incident light. , could not be deflected in the desired direction.
  • the luminous flux of emitted light is normal direction (that is, microlens light axial direction) was symmetrically diffused and emitted. Therefore, since the direction of the principal ray of the emitted light (diffused light) is always the normal direction, the emitted light flux can be tilted in a desired direction with respect to the normal direction to deflect the incident light flux. I could't do it.
  • the macroscopic output direction of the emitted light (diffused light) that passes through the diffuser plate and is diffused cannot be tilted in a direction different from that of the incident light due to the refraction effect of the diffuser plate. be.
  • the optical axis of the conventional microlens is parallel to the normal direction (Z direction) of the diffuser plate as described above, the emitted light beam is deflected in a desired direction, which is different from the normal refraction action of the diffuser plate. i could't let it go.
  • a diffusion plate with a microlens array capable of
  • the present invention has been made in view of the above problems, and an object of the present invention is to provide a diffusion plate capable of deflecting emitted light in a desired direction, and a display device having the same. , to provide a projection device and a lighting device.
  • a microlens array type diffusion plate a substrate; a microlens array composed of a plurality of microlenses randomly arranged on the XY plane on at least one surface of the substrate; with The surface shape of the microlens has an aspherical shape, A diffusion plate is provided in which the optical axes of the microlenses are inclined at an inclination angle ⁇ of 1° or more with respect to the Z direction, which is the normal direction to the surface of the base material.
  • the principal ray of the emitted light emitted from the diffusion plate is deflected with respect to the principal ray of the incident light incident on the diffusion plate. You may do so.
  • the direction in which the principal ray of the emitted light is deflected is opposite to the tilt direction of the optical axis of the microlens. good too.
  • the surface shape of the microlens may have a rotationally symmetrical aspheric shape about the optical axis tilted at the tilt angle ⁇ .
  • the surface shape of the microlens may have a tilted aspherical shape obtained by rotating the reference aspherical shape having the optical axis in the Z direction by the tilt angle ⁇ in the tilting direction of the optical axis.
  • the apex of the microlens is the apex of the inclined aspheric surface, and may be arranged at a position shifted from the optical axis inclined by the inclination angle ⁇ .
  • the conic coefficient K may be greater than zero.
  • the The aspect ratio k may be 0.1 or more and 1.1 or less.
  • the inclination angle ⁇ may be 60° or less.
  • the inclination angle ⁇ may be 45° or less.
  • the optical axes of the plurality of microlenses may be tilted at substantially the same tilt angle ⁇ and in substantially the same tilt direction.
  • the optical axes of the plurality of microlenses may be tilted in mutually different tilting directions at mutually different tilting angles ⁇ .
  • the tilt angle ⁇ may vary randomly within a predetermined variation range with reference to a predetermined reference tilt angle ⁇ k.
  • the azimuth angles ⁇ of the optical axes of the plurality of microlenses are different from each other,
  • the azimuth angle ⁇ may vary randomly within a predetermined variation range with reference to a predetermined reference azimuth angle ⁇ k.
  • the aperture width D of the microlens varies randomly based on a predetermined reference aperture width Dk
  • the radius of curvature R of the microlens may vary randomly based on a predetermined reference radius of curvature Rk.
  • the plurality of microlenses may be randomly arranged so that the overlapping amount Ov between the microlenses adjacent to each other on the XY plane is within a preset allowable range.
  • the outline of the planar shape of the microlens may be composed of a plurality of curves having different curvatures.
  • another aspect of the present invention provides a display device including the diffusion plate.
  • another aspect of the present invention provides a projection device including the diffusion plate.
  • a lighting device including the diffusion plate described above.
  • the luminous flux of emitted light can be deflected in a desired direction.
  • FIG. 1A and 1B are a plan view and an enlarged view schematically showing a diffusion plate according to an embodiment of the present invention
  • FIG. 3A and 3B are an enlarged plan view and an enlarged cross-sectional view schematically showing the configuration of a diffuser plate according to the same embodiment
  • FIG. 4 is an enlarged cross-sectional view schematically showing the vicinity of the boundary of microlenses according to the same embodiment.
  • FIG. FIG. 4 is a plan view schematically showing the planar shape (outer shape) of the microlens according to the embodiment; It is a schematic diagram which shows the aspect which inclines the optical axis of the micro lens which concerns on the same embodiment. It is a schematic diagram which shows the deflection function of the microlens based on the same embodiment.
  • FIG. 4 is an explanatory diagram showing a planar shape of an anamorphic microlens according to the same embodiment;
  • FIG. 4 is a perspective view showing a three-dimensional shape of an anamorphic microlens according to the embodiment; It is an explanatory view showing a planar shape of a torus-shaped microlens according to the same embodiment.
  • FIG. 4 is a perspective view showing a three-dimensional shape of a torus-shaped microlens according to the embodiment; It is a perspective view which shows the torus-shaped curved surface which concerns on the same embodiment.
  • FIG. 4 is a perspective view showing a three-dimensional shape of a torus-shaped microlens according to the embodiment; It is a perspective view which shows the torus-shaped curved surface which concerns on the same embodiment.
  • FIG. 4A is a cross-sectional view and a plan view schematically showing a specific example of a microlens array in which a plurality of microlenses are arranged according to the same embodiment.
  • FIG. 4A is a cross-sectional view and a plan view schematically showing a specific example of a microlens array in which a plurality of microlenses are arranged according to the same embodiment.
  • FIG. 4A is a cross-sectional view and a plan view schematically showing a specific example of a microlens array in which a plurality of microlenses are arranged according to the same embodiment.
  • FIG. 4A is a cross-sectional view and a plan view schematically showing a specific example of a microlens array in which a plurality of microlenses are arranged according to the same embodiment.
  • 4A is a cross-sectional view and a plan view schematically showing a specific example of a microlens array in which a plurality of microlenses are arranged according to the same embodiment.
  • 4 is a flow chart showing a microlens design method according to the same embodiment.
  • 4 is a plan view showing the arrangement of lens center coordinates of microlenses according to the same embodiment.
  • FIG. FIG. 4 is a plan view showing the arrangement of microlenses having rotationally symmetric aspherical shapes according to the same embodiment.
  • 3A and 3B are a plan view and a perspective view showing the arrangement of microlenses having a rotationally asymmetric aspherical shape according to the same embodiment.
  • FIG. 4 is a perspective view showing a method of determining a reference aspheric surface shape of a microlens according to the same embodiment;
  • FIG. 4 is a perspective view showing a method of inclining a reference aspheric surface shape of a microlens according to the same embodiment;
  • 4 is a flow chart showing a method for manufacturing a diffuser plate according to the same embodiment.
  • FIG. 10 is an explanatory diagram of a diffusion plate according to Comparative Example 1;
  • FIG. 11 is an explanatory diagram of a diffusion plate according to Comparative Example 2;
  • FIG. 4 is an explanatory diagram of a diffusion plate according to Example 1;
  • FIG. 4 is a confocal laser microscope image showing surface shape patterns of a plurality of types of microlens arrays according to an example.
  • 4 is a confocal laser microscope image showing surface shape patterns of a plurality of types of microlens arrays according to an example.
  • the diffuser plate according to this embodiment is a microlens array type diffuser plate that has a function of uniformly diffusing light.
  • a diffusion plate has a base material and a microlens array formed on the XY plane on at least one surface (principal surface) of the base material.
  • the microlens array is composed of a plurality of microlenses randomly arranged and developed on the XY plane.
  • the microlens has a convex structure (convex lens) or concave structure (concave lens) having a light diffusion function, and has, for example, an aperture width D (lens diameter) of about several tens of ⁇ m and a curvature radius R of about several tens of ⁇ m. .
  • each microlens has an aspherical shape
  • each microlens is an aspherical lens.
  • the optical axis of each microlens is inclined at an inclination angle ⁇ of, for example, more than 0° and 60° or less with respect to the normal direction (Z direction) to the surface (XY surface) of the flat base material of the diffuser plate. are doing.
  • the aspherical microlens is rotated in an arbitrary direction to tilt the optical axis itself at the tilt angle ⁇ .
  • emitted light diffused light
  • the emitted light beam can be bent in a desired direction. Therefore, the degree of freedom of the incident direction (incident angle ⁇ in) of the incident light with respect to the diffusion plate and the degree of freedom of the output direction (output angle ⁇ out) of the emitted light can be improved. Therefore, it is possible to expand the degree of freedom in designing the light incident on the diffusion plate and the light emitted from the diffusion plate in the optical axis direction, and to downsize the optical equipment system in which the diffusion plate is mounted.
  • a plurality of microlenses are arranged at random positions on the XY plane of the base material of the diffuser plate.
  • multiple microlenses may be arranged at random positions while overlapping each other so that the amount of overlap Ov between multiple microlenses adjacent to each other is within a predetermined allowable range. good.
  • the aperture width D (lens diameter) and curvature radius R of each microlens may vary randomly such that the aperture width D (lens diameter) and curvature radius R of the microlenses are different from each other.
  • the tilt angle ⁇ is the tilt angle (0 to 90°) of the optical axis of the microlens with respect to the normal direction (Z direction) of the surface of the diffusion plate.
  • the azimuth angle ⁇ is an angle representing the tilt direction of the optical axis of the microlens on the XY plane, and is represented, for example, by an angle (0° to 360°) of the tilt direction with respect to the X-axis direction.
  • the tilt angle ⁇ and the azimuth angle ⁇ may be substantially the same fixed values among the plurality of microlenses.
  • the tilt angle ⁇ and the azimuth angle ⁇ may have mutually different variation values among the plurality of microlenses, or may vary randomly.
  • the arrangement of a plurality of microlenses, the aperture width D, the radius of curvature R, the tilt angle ⁇ , the azimuth angle ⁇ , etc. may be changed at random.
  • the surface shapes of the plurality of microlenses that are developed and arranged on the XY plane vary randomly and have mutually different shapes.
  • a three-dimensional surface structure of the microlens array with high randomness can be realized, so that it is possible to control the overlapping state of the phases of the diffused light emitted from each microlens. Therefore, it is possible to reduce unevenness in the intensity distribution of the diffused light due to interference and diffraction of the diffused light emitted from the plurality of microlenses, and to uniformly distribute the diffused light. As a result, it is possible to control the cut-off property of the intensity distribution of the diffused light while having high transmittance luminance characteristics and satisfying the homogeneity of the light distribution of the diffused light.
  • FIG. 1 is a plan view and an enlarged view schematically showing a diffusion plate 1 according to this embodiment.
  • the diffusion plate 1 is a microlens array type diffusion plate in which a microlens array composed of a plurality of microlenses (single lenses) is arranged on a substrate.
  • the microlens array of the diffusion plate 1 is composed of a plurality of unit cells 3, as shown in FIG.
  • a unit cell 3 is a basic arrangement pattern of microlenses.
  • a plurality of microlenses are arranged in a predetermined layout pattern (arrangement pattern) on the surface of each unit cell 3 .
  • FIG. 1 shows an example in which the shape of the unit cells 3 constituting the microlens array of the diffusion plate 1 is rectangular, particularly square.
  • the shape of the unit cell 3 is not limited to the example shown in FIG. Any shape may be used as long as it can be filled.
  • the unit cells 3 correspond to individual unit areas.
  • a plurality of square unit cells 3 are repeatedly arranged vertically and horizontally on the surface of the diffusion plate 1 .
  • the number of unit cells 3 constituting the diffusion plate 1 is not particularly limited, and the diffusion plate 1 may be composed of one unit cell 3, or may be composed of a plurality of unit cells 3.
  • the unit cells 3 having different surface structures may be arranged repeatedly, or the unit cells 3 having the same surface structure may be arranged repeatedly.
  • a microlens array is configured by arranging the unit cells 3 without gaps while maintaining the continuity of the microlenses at the boundaries between a plurality of unit cells 3 adjacent to each other.
  • the continuity of the microlenses means that the microlenses positioned at the outer edge of one unit cell 3 and the microlenses positioned at the outer edge of the other unit cell 3 among the two unit cells 3, 3 adjacent to each other. It means that the lens is continuously connected without deviation of the planar shape or step in the height direction.
  • the microlens array is configured by arranging the unit cells 3 (basic structure) of the microlens array without gaps while maintaining the continuity of the boundaries. .
  • unintended problems such as diffraction, reflection, and scattering of light are prevented from occurring at the boundaries between the unit cells 3, 3 adjacent to each other, and the desired light distribution characteristics of the diffusion plate 1 can be obtained.
  • the microlens array into a repeating structure of the unit cells 3, the design efficiency and productivity of the microlens array can be improved.
  • FIG. 2A and 2B are an enlarged plan view and an enlarged cross-sectional view schematically showing the configuration of the diffusion plate 1 according to this embodiment.
  • FIG. 3 is an enlarged sectional view schematically showing the vicinity of the boundary of the microlens 21 according to this embodiment.
  • FIG. 4 is a plan view schematically showing the planar shape (outer shape) of the microlens 21 when the microlens 21 is viewed from a direction perpendicular to the surface of the substrate 10 according to this embodiment.
  • the diffuser plate 1 includes a substrate 10 and a microlens array 20 formed on the surface of the substrate 10 .
  • the base material 10 is a substrate for supporting the microlens array 20 .
  • a substrate 10 may be film-like or plate-like.
  • the base material 10 may be flat plate-like or curved plate-like.
  • the substrate 10 shown in FIG. 2 has, for example, a rectangular flat plate shape, but is not limited to such an example.
  • the shape and thickness of the base material 10 may be any shape and thickness depending on the shape, configuration, etc. of the device in which the diffusion plate 1 is mounted.
  • the base material 10 is a transparent base material capable of transmitting light.
  • the base material 10 is made of a material that can be regarded as transparent in the wavelength band of light incident on the diffuser plate 1 .
  • the base material 10 may be made of a material having a light transmittance of 70% or more in the visible light wavelength band.
  • the substrate 10 is made of, for example, polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), cyclic olefin copolymer (COC), cyclic olefin polymer (Cyclo It may be made of a known resin such as Olefin Polymer (COP), triacetylcellulose (TAC), or the like.
  • the base material 10 may be made of known optical glass such as quartz glass, borosilicate glass, and white plate glass.
  • the microlens array 20 is provided on at least one surface (principal surface) of the substrate 10 .
  • the microlens array 20 is an assembly of a plurality of microlenses 21 (single lenses) arranged on the surface of the substrate 10 .
  • the microlens array 20 is formed on one surface (principal surface) of the base material 10 .
  • the invention is not limited to such an example, and the microlens arrays 20 may be formed on both main surfaces (front surface and back surface) of the substrate 10 .
  • the surface of the substrate 10 on which the microlens array 20 is provided may be, for example, a flat surface.
  • the flat surface of the said base material 10 may be called XY plane.
  • the X direction and Y direction on the XY plane are directions parallel to the surface of the base material 10 .
  • the X and Y directions are perpendicular to each other.
  • the Z direction is a direction perpendicular to the surface of the base material 10 (that is, the normal direction) and corresponds to the thickness direction of the diffusion plate 1 .
  • the Z direction is perpendicular to the XY plane, the X direction and the Y direction.
  • the microlens 21 is, for example, a fine optical lens on the order of several tens of ⁇ m.
  • the microlens 21 constitutes a single lens of the microlens array 20 .
  • the microlenses 21 may be concave structures (concave lenses) that are recessed in the thickness direction of the diffuser plate 1 , or convex structures (convex lenses) that are formed to protrude in the thickness direction of the diffuser plate 1 . may be In this embodiment, an example in which the microlenses 21 have a convex structure (convex lenses) as shown in FIG. 2 will be described, but the present invention is not limited to such an example.
  • the microlenses 21 may be concave structures (concave lenses).
  • the surface shape of the microlens 21 has an aspherical shape.
  • the surface shape of the microlens 21 is not particularly limited as long as it is a curved surface shape including at least a portion of an aspheric component.
  • the surface shape of the microlens 21 may be an aspherical shape containing only an aspherical surface component, or a curved surface shape containing an aspherical surface component and a spherical component or other curved surface component.
  • the surface shape of the portion on the lens surface vertex side of the microlens 21 may be an aspherical shape, and the surface shape of the other portion may be a spherical shape.
  • Such a surface shape is also included in the aspheric shape of the microlens 21 according to this embodiment.
  • the plurality of microlenses 21 are preferably densely arranged so as to be adjacent to each other without gaps. In other words, it is preferable that the plurality of microlenses 21 be arranged continuously so that there is no gap (flat portion) at the boundary between the adjacent microlenses 21 . It is preferable that the microlenses 21 are arranged on the substrate 10 without gaps. In other words, it is preferable that the microlenses 21 are arranged so that the filling factor is 100%. This makes it possible to suppress a component of the incident light that is not scattered on the surface of the diffuser plate 1 and is transmitted as it is (hereinafter also referred to as a "zero-order transmitted light component"). As a result, the diffusion performance can be further improved by the microlens array 20 in which a plurality of microlenses 21 are arranged adjacent to each other without gaps.
  • the filling rate of the microlenses 21 on the substrate 10 is preferably 90% or more, more preferably 100%.
  • the filling rate is the ratio of the area occupied by the plurality of microlenses 21 on the surface of the substrate 10 (on the XY plane). If the filling rate is 100%, the surface of the microlens array 20 is formed of curved surface components and contains substantially no flat surface components.
  • the vicinity of the inflection point on the boundary between the mutually adjacent microlenses 21 should be substantially flat.
  • the width of the region near the inflection point that is substantially flat is 1 ⁇ m. The following are preferable. Thereby, the 0th-order transmitted light component can be sufficiently suppressed.
  • the plurality of microlenses 21 are randomly (irregularly) arranged on the XY plane.
  • “random” means that there is no substantial regularity in the arrangement of the microlenses 21 in any given area of the microlens array 20 .
  • it is included in the "irregularity”.
  • a method of randomly arranging the microlenses 21 in the microlens array 20 according to this embodiment will be described later.
  • the lens parameters such as the aperture width D and the radius of curvature R that determine the surface shape of each microlens 21 may vary randomly for each microlens 21 . That is, the aperture width D and the radius of curvature R of each microlens 21 may be variable values that vary randomly instead of predetermined fixed values.
  • the aperture width D is the width of the aperture 27 of the microlens 21 in the X direction or the Y direction (see FIG. 5), and corresponds to the lens diameter of the microlens 21 .
  • the curvature radius R is the curvature radius of the curved surface shape of the microlens 21 in the X direction or the Y direction.
  • the aperture width D and the curvature radius R can be varied appropriately around the predetermined reference aperture width Dk and the reference curvature radius Rk, so that the desired optical characteristics (diffusion performance) of the diffusion plate 1 can be maintained.
  • the radius of curvature R and the aperture width D of each microlens 21 vary randomly within a predetermined range around the reference radius of curvature Rk and the reference aperture width Dk. , has scatter.
  • the phase distribution of the optical aperture of each microlens 21 differs depending on the orientation.
  • the plurality of microlenses 21 are densely and continuously arranged so as to overlap each other, and the individual microlenses 21 are randomly positioned on the XY plane. are placed in
  • each microlens 21 randomly fluctuate based on a predetermined reference shape.
  • the surface shape and planar shape of each microlens 21 are different from each other. Therefore, as schematically shown in FIG. 2, the plurality of microlenses 21 come to have various planar shapes, and many of them do not have symmetry.
  • the microlens 21A has a radius of curvature RA
  • the microlens 21B adjacent to the microlens 21A has a radius of curvature RB ( ⁇ RA ) .
  • the boundary line 24 between the microlenses 21A and 21B does not consist only of a straight line, but at least partially includes a curve. become configured.
  • the outline of the planar shape of the microlens 21 (boundary line 24 between the microlens 21 and other adjacent microlenses 21) is composed of a plurality of curves having mutually different curvatures. become.
  • the boundary line 24 between the microlenses 21, 21 adjacent to each other includes a plurality of curves with different curvatures, the regularity of the boundary between the microlenses 21, 21 is further broken, so that the diffused light can be further reduced.
  • FIG. 5 is a schematic diagram showing a mode of tilting the optical axis 25 of the microlens 21 according to this embodiment.
  • the upper diagram (FIG. 5A) in FIG. 5 shows the surface shape (reference aspheric surface shape) of the microlens 21 before the optical axis 25 is tilted.
  • the lower diagram in FIG. 5 shows the surface shape (tilted aspherical shape) of the microlens 21 after the optical axis 25 is tilted.
  • the surface 26 of the microlens 21 may be referred to as the "lens surface 26", and the surface shape of the microlens 21 (that is, the curved surface shape of the lens surface 26) may be referred to as the "lens surface shape”.
  • the curved surface shape (lens surface shape) of the lens surface 26 of the microlens 21 has, for example, an aspheric shape such as an ellipsoid, a paraboloid, or a hyperboloid.
  • FIG. 5 shows an example in which the aspherical shape of the lens surface 26 is an elliptical surface elongated in the direction of the optical axis 25 (conic coefficient K>0).
  • the ellipsoid means an ellipsoid of revolution, which is the surface of a spheroid.
  • a spheroid is a body of revolution obtained by rotating an ellipse with its major or minor axis as the axis of rotation.
  • An ellipsoid for K>0 is the surface of a spheroid (that is, a long ellipsoid) whose axis of rotation is the major axis of the ellipse.
  • the ellipsoid in the case of ⁇ 1 ⁇ K ⁇ 0 is the surface of a spheroid (that is, oblate ellipsoid) obtained with the minor axis of the ellipse as the axis of rotation. In either case, the axis of rotation of the spheroid coincides with the optical axis 25 of the microlens 21 .
  • the optical axis 25 of the microlens 21 when the optical axis 25 of the microlens 21 is not tilted, the optical axis 25 of the microlens 21 is in the normal direction (Z direction) to the surface (XY plane) of the substrate 10 of the diffusion plate 1. ). That is, the optical axis 25 overlaps the Z axis.
  • the surface shape of the microlens 21 also becomes a reference aspheric surface shape (FIG. 5A) that is not inclined with respect to the Z direction.
  • the reference aspherical shape according to the present embodiment is, for example, a rotationally symmetrical aspherical shape about the normal direction (Z direction) to the XY plane.
  • the reference aspherical shape may be, for example, an aspherical shape rotationally asymmetric about the Z direction as long as the optical axis 25 is parallel to the Z direction. If the lens surface shape is a reference aspheric shape, the vertex 28 of the microlens 21 is located on the optical axis 25 and the Z axis.
  • the reference aspheric shape (FIG. 5A) is a lens surface shape that serves as a reference when designing the inclined aspheric shape (FIG. 5B).
  • the aperture width D of the microlens 21 is the width (lens diameter) of the aperture 27 of the microlens 21 on the XY plane.
  • the opening width D is represented by an opening width Dx in the X direction and an opening width Dx in the X direction.
  • the radius of curvature R of the microlens 21 is the radius of curvature at the top of the lens surface shape.
  • the radius of curvature R is represented by the radius of curvature Rx in the X direction and the radius of curvature Ry in the Y direction. As shown in FIG.
  • the optical axis 25 of the microlens 21 according to the present embodiment is arranged in a predetermined It is tilted at the tilt angle ⁇ .
  • the tilt angle ⁇ is the angle between the optical axis 25 and the normal direction (Z direction).
  • the tilt direction of the optical axis 25 is represented by the azimuth angle ⁇ .
  • the azimuth angle ⁇ is the angle between the optical axis 25 projected onto the XY plane and the X direction when the inclined optical axis 25 is projected onto the XY plane.
  • the lens surface 26 of the microlens 21 is also inclined at the inclination angle ⁇ in the inclination direction represented by the azimuth angle ⁇ .
  • the lens surface shape of the tilted microlens 21 becomes an aspherical shape obtained by tilting the reference aspherical shape (FIG. 5A), that is, an inclined aspherical shape (FIG. 5B).
  • the surface shape of the microlens 21 also changes in the tilt direction represented by the azimuth angle ⁇ . It becomes an oblique aspherical shape that is inclined at an inclination angle ⁇ with respect to the Z direction.
  • This inclined aspherical shape (FIG. 5B) is a shape obtained by rotating the reference aspherical shape (FIG. 5A) by the inclination angle ⁇ about the center point 30 of the reference aspherical shape.
  • Such a tilted aspherical shape is a rotationally symmetrical aspherical shape about the optical axis 25 tilted at the tilt angle ⁇ .
  • the center point 30 is the origin (x, y, z) when designing the reference aspheric shape of the microlens 21 .
  • the opening surface of the reference aspherical shape of the microlens 21 is designed to be a circle, an ellipse, or the like.
  • FIG. 5 shows the center point 30 on the surface (XY plane) of the substrate 10, the center point 30 does not have to be on the XY plane.
  • the vertex 28 of the microlens 21 is located on the optical axis 25 and the Z axis.
  • the vertex 29 of the lens surface 26 of the tilted microlens 21 is different from the vertex 28 of the lens surface 26 shown in FIG. 5A. Move to different positions.
  • This vertex 29 is the highest point in the Z direction of the inclined aspherical shape (FIG. 5B), and is located at a position shifted from the optical axis 25 inclined by the inclination angle ⁇ .
  • the optical axis 25 of the microlens 21 and the lens surface shape are tilted, and the apex 29 of the microlens 21 is shifted from the optical axis 25 .
  • the emitted light (diffused light) that is emitted after passing through the microlens 21 can be deflected with respect to the incident light.
  • Deflection means bending the direction of the principal ray of the emitted light in a desired direction with respect to the direction of the principal ray of the incident light, thereby deflecting the main traveling direction of the emitted light (diffused light) in the desired direction. do.
  • FIG. 6 is a schematic diagram showing the deflection function of the microlens 21 according to this embodiment.
  • the upper diagram (FIG. 6A) in FIG. 6 shows the diffusion function of transmitted light by the microlenses 21 whose optical axes 25 are not inclined.
  • the lower diagram in FIG. 6 (FIG. 6B) shows the function of diffusing and deflecting the transmitted light by the microlens 21 with the optical axis 25 inclined.
  • the incident angle ⁇ in of the incident light 40 is 0°
  • the direction of the chief ray 41 of the incident light 40 is parallel to the Z direction.
  • the optical axis 25 of the microlens 21 when the optical axis 25 of the microlens 21 is not tilted, the light passing through the microlens 21 is symmetrical about the direction of the optical axis 25 of the microlens 21 (the Z direction). spread to Therefore, the emitted light 50 becomes diffused light that diffuses symmetrically about the Z direction. As a result, the output angle ⁇ out of the principal ray 51 of the output light 50 becomes 0°, and the direction of the principal ray 51 of the output light 50 becomes parallel to the Z direction.
  • the principal ray 51 of the emitted light 50 emitted from the diffuser plate 1 becomes the principal ray 41 of the incident light 40. bias against.
  • the light passing through the diffuser plate 1 is diffused substantially symmetrically around a deflection direction different from the Z direction.
  • This deflection direction is the direction in which the principal ray 51 of the output light 50 is bent with respect to the principal ray 41 of the incident light 40, and is represented by the deflection angle ⁇ .
  • the deflection direction of the principal ray 51 of the emitted light 50 is the optical axis 25 of the microlens 21. It is the opposite direction (left direction in FIG. 6B) to the tilt direction (right direction in FIG. 6B).
  • the deflection angle ⁇ representing this deflection direction is determined by the tilt angle ⁇ of the optical axis 25, the tilted aspheric shape of the microlens 21, the position of the vertex 29, and the like.
  • the deflection angle ⁇ changes according to the tilt angle ⁇ . If the lens surface shape is the same, the greater the tilt angle ⁇ , the greater the deflection angle ⁇ .
  • the optical axis 25 of the microlens 21 is tilted at the tilt angle ⁇
  • the light flux of the emitted light 50 is deflected in the direction of deflection (the direction represented by the deflection angle ⁇ ) with respect to the light flux of the incident light 40.
  • the diffused light is deflected and diffuses substantially symmetrically with respect to the deflection direction.
  • the output angle ⁇ out of the principal ray 51 of the output light 50 becomes ⁇ °
  • the direction of the principal ray 51 of the output light 50 is a direction inclined by the deflection angle ⁇ with respect to the Z direction
  • the optical axis 25 is the direction opposite to the direction of inclination of .
  • the optical axis 25 of each microlens 21 constituting the microlens array 20 is aligned in the normal direction (Z direction) of the surface (XY plane) of the substrate 10 of the diffusion plate 1. ).
  • the lens surface shape of each microlens 21 is a tilted aspherical shape (FIGS. 5B, 6B) obtained by rotating the reference aspherical shape (FIGS. 5A, 6A) in the same direction at the tilt angle ⁇ .
  • the lens surface shape is also inclined following the inclination of the optical axis 25 .
  • the direction of the emitted light 50 can be bent in the direction opposite to the tilt direction of the optical axis 25 with respect to the direction of the incident light 40, and the emitted light 50 can be deflected in a desired direction. Therefore, according to this embodiment, the emitted light 50 can be deflected in a direction different from the direction of refraction by the normal refraction action of the diffusion plate 1 .
  • the incident light incident on the diffusion plate 1 according to the present embodiment may be, for example, collimated light collimated by an optical system, or may be diffused light incident from one point light source. However, diffused light or collimated light that is incident from a plurality of light sources arranged in the same direction with respect to the diffusion plate 1 may also be used.
  • the microlens array 20 according to this embodiment can suitably deflect these incident lights.
  • the tilt angle ⁇ of the optical axis 25 of the microlens 21 is preferably 60° or less. If the tilt angle ⁇ exceeds 60°, the surface shape of the microlens 21 will be destroyed, and the microlens 21 will have extreme anisotropy. For this reason, it becomes difficult to mold the microlenses 21 that are excessively inclined, and the feasibility of the microlens array structure may decrease. In addition, it may become difficult to clearly manifest the deflection function of the emitted light, and the optical characteristics of the microlenses 21 may also deteriorate.
  • the inclination angle ⁇ should be 60. ° or less.
  • the inclination angle ⁇ is more preferably 45° or less. If the tilt angle ⁇ is more than 45°, diffused light noise may easily occur depending on the shape of the tilted microlens 21 .
  • This lens shape-dependent noise includes, for example, zero-order diffracted light noise or spectral noise.
  • Spectral noise is noise composed of extraordinary light that has been refracted and scattered, and relatively periodic peak-shaped diffracted light, and is generated by a diffraction phenomenon caused by discontinuity in the shape of the microlens array 20 . Therefore, in order to reduce the noise of the diffused light caused by the microlenses 21, the tilt angle ⁇ is preferably 45° or less.
  • the inclination angle ⁇ is preferably 1° or more. If the tilt angle ⁇ is less than 1°, the realization of the deflection function becomes uncertain due to the formation error of the microlenses 21 and the limit of the detection accuracy of the deflection angle, and the deflection function of the emitted light becomes insufficient. Sometimes. Therefore, in order to suitably realize the deflection function, the inclination angle ⁇ is preferably 1° or more, more preferably 2° or more.
  • the surface shape (lens surface shape) of the microlens 21 according to the present embodiment is preferably a rotationally symmetrical aspherical shape around the optical axis 25 inclined at the inclination angle ⁇ , as shown in FIG. .
  • K is a conic coefficient, which is used in the formula that defines the shape of the aspherical surface.
  • the lens surface shape according to the present embodiment is preferably a tilted aspheric surface shape rotationally symmetrical about the tilted optical axis 25 .
  • the microlens 21 with the tilted optical axis 25 can be relatively easily designed and manufactured.
  • the microlens 21 can suitably deflect the emitted light 50 in a desired direction, and the accuracy and uniformity of the deflection function can be enhanced.
  • the conic coefficient K in the aspherical lens formula is more than 0. Preferred (K>0). If K>0, the lens surface shape is an ellipsoid elongated in the direction of the optical axis 25 . As a result, there is an effect that it is easy to achieve both the deflection function and the diffusion control.
  • each parameter is as follows.
  • K conic coefficient
  • A4 , A6 4th and 6th order aspheric coefficients
  • the aspect ratio k of the surface shape of the microlens 21 (that is, the aspheric shape) is preferably 0.1 or more and 1.1 or less, and is 0.2 or more and 0.6 or less. is more preferred. As a result, the controllability of the diffusion angle and the feasibility of forming the structure of the microlens 21 can be easily obtained.
  • the maximum lens apex height h1 is the apex height of the microlens 21 having the highest apex height among the plurality of microlenses 21 included in one unit cell 3 shown in FIG.
  • the minimum boundary point height h2 is the lowest height of the boundary line around the microlens 21 .
  • the microlens 21 according to the present embodiment preferably has a tilted aspheric shape rotationally symmetrical about the tilted optical axis 25 .
  • This rotationally symmetric tilted aspherical shape is an aspherical shape having isotropy about the optical axis 25 .
  • the surface shape of the microlens 21 is not limited to this example. It may be spherical.
  • the lens surface shape is a rotationally asymmetric aspherical shape or an anisotropic aspherical shape, if the optical axis 25 of the microlens 21 is tilted, the tilted optical axis 25 will It is possible to deflect the emitted light in a desired direction.
  • FIG. 7 An example in which the surface shape of the microlens 21 is rotationally asymmetric with respect to the optical axis 25 and has an anisotropic aspherical shape will be described below with reference to FIGS. 7 to 11.
  • FIG. 7 For example, an anamorphic shape, a torus shape, or the like can be used as the aspheric shape having anisotropy extending in a predetermined direction.
  • FIG. 7 is an explanatory diagram showing the planar shape of the anamorphic microlens 21.
  • FIG. 8 is a perspective view showing the three-dimensional shape of the anamorphic microlens 21. As shown in FIG.
  • the microlens 21 shown in FIGS. 7 and 8 is a so-called anamorphic lens, and its surface shape is an aspherical shape including an anamorphic curved surface.
  • the planar shape of the microlens 21 is an anisotropic elliptical shape.
  • the major axis in the Y-axis direction of the elliptical shape is Dy
  • the minor axis in the X-axis direction is Dx.
  • the surface shape of the microlens 21 is an aspherical curved surface having predetermined curvature radii Rx and Ry in the long axis direction and the short axis direction of the ellipse.
  • Such a microlens 21 has an aspherical shape having anisotropy in the Y-axis direction.
  • the anamorphic curved surface (aspherical surface) shown in FIG. 8 is represented by the following formula (1).
  • the following formula (1) is an example of a formula representing an anamorphic curved surface (aspherical surface).
  • each parameter is as follows.
  • Ry Radius of curvature in the Y direction
  • Kx Conic coefficient in the X direction
  • Ky Conic coefficient in the Y direction
  • a x4 Third and sixth aspheric coefficients in the X direction
  • a y6 Fourth and sixth aspheric coefficients in the Y direction
  • the short axis in the X direction of the elliptical shape on the XY plane is Dx
  • the long axis in the Y direction is Dy.
  • the curved surface shape of the cut part is set as the surface shape (anamorphic shape) of the microlens 21 .
  • the major axis Dy of the elliptical shape, the minor axis Dx, the radius of curvature Ry in the Y direction (major axis direction), and the radius of curvature Rx in the X direction (minor axis direction) are set to a predetermined variation rate ⁇ Randomly fluctuate within the range of .
  • the surface shapes of the plurality of microlenses 21 having different anamorphic shapes can be set.
  • FIG. 9 is an explanatory diagram showing the planar shape of the torus-shaped microlens 21 .
  • FIG. 10 is a perspective view showing the three-dimensional shape of the torus-shaped microlens 21.
  • FIG. 11 is a perspective view showing a torus-shaped curved surface.
  • the surface shape of the microlens 21 is an aspheric shape including a curved surface of a torus shape.
  • a torus is a surface of revolution obtained by rotating a circle. Specifically, as shown in FIG. 11, the small circle (radius: R) is rotated along the circumference of the large circle (radius: R) around the rotation axis (X-axis) arranged outside the small circle (radius: r). By rotating the circle, a so-called donut-shaped torus is obtained. The curved shape of the surface of this torus (torus surface) is the torus shape. By cutting out the outer portion of the torus shape, a three-dimensional shape of the torus-shaped microlens 21 as shown in FIG. 10 is obtained.
  • the planar shape of the torus-shaped microlens 21 is an anisotropic elliptical shape.
  • the major axis of the elliptical shape in the Y-axis direction is R
  • the minor axis in the X-axis direction is r.
  • These r and R correspond to the aperture widths Dx and Dy of the microlens 21 in the X direction and the Y direction.
  • the three-dimensional shape of the microlens 21 is composed of an aspherical curved surface having predetermined curvature radii R and r in the major axis direction and the minor axis direction of the ellipse.
  • Such a microlens 21 has an aspherical shape having anisotropy in the Y-axis direction.
  • FIG. 11 is a perspective view showing an aspheric curved surface represented by the following formula (2). Note that in equation (2), R is the radius of the great circle and r is the radius of the small circle.
  • the curved surface is formed so that the short axis in the X direction of the elliptical shape on the XY plane is r and the long axis in the Y direction is R. cut out.
  • the curved surface shape of the cut part is set as the curved surface shape (torus shape) of the microlens 21 .
  • the major axis Dy of the elliptical shape, the minor axis Dx, the radius of curvature R in the Y direction (major axis direction) (equivalent to the radius of curvature Ry of the lens), and the radius of curvature r in the X direction (minor axis direction) (of the lens equivalent to the radius of curvature Rx) is randomly varied within a range of a predetermined variation rate ⁇ for each microlens 21 to vary.
  • the surface shapes of the plurality of microlenses 21 having mutually different torus shapes can be set.
  • Aspherical shapes such as the anamorphic shape and the torus shape described above are not rotationally symmetrical shapes about the optical axis 25 of the microlens 21 .
  • the aspherical shape is symmetrical in the Y direction with respect to the XZ plane including the optical axis 25 and symmetrical in the X direction with respect to the YZ plane including the optical axis 25 .
  • the surface shape of the microlens 21 may be an aspheric shape (for example, an anamorphic shape, a torus shape) having such symmetry and anisotropy.
  • the optical axis 25 of the microlens 21 having the aspherical shape is tilted and the lens surface shape is rotated and tilted in the tilting direction, the effect of the tilted optical axis 25 and the lens surface shape , the emitted light can be deflected in a desired direction. Furthermore, mutually different diffusion characteristics can be obtained in the X direction and the Y direction.
  • an aspherical shape cut out from an elliptical sphere for example, can be used.
  • FIGS. 12 to 15 are sectional views and plan views schematically showing specific examples of a microlens array 20 in which a plurality of microlenses 21 are randomly arranged according to this embodiment.
  • the tilt angle ⁇ of the optical axis 25 with respect to the Z direction is substantially the same, and the azimuth angle representing the tilt direction of the optical axis 25 is The angles ⁇ are also substantially identical.
  • the tilt angle ⁇ of all the microlenses 21 is substantially the same as the predetermined reference tilt angle ⁇ k, and the azimuth angle of all the microlenses 21 is ⁇ is substantially the same as the reference azimuth angle ⁇ k.
  • the reference tilt angle ⁇ k is a fixed value that serves as a reference for the tilt angle ⁇ , and is set to an angle corresponding to a desired degree of tilt in the deflection direction.
  • the reference azimuth angle ⁇ k is a fixed value that serves as a reference for the azimuth angle ⁇ , and is set to an angle corresponding to the azimuth of the desired deflection direction.
  • ⁇ ⁇ k (10)
  • ⁇ ⁇ k (11)
  • the surface shape of the plurality of microlenses 21 is a paraboloid (optical axis: Z-axis) represented by the following formula (12).
  • the radius of curvature R of each microlens 21 can also be set to a predetermined value based on a predetermined reference radius of curvature Rk, as shown in the following equation (14). will vary randomly within the range of the variation rate ⁇ R. As a result, the curvature radii R of the plurality of microlenses 21 have mutually different values.
  • R Rk [ ⁇ m] ⁇ R [%] (14)
  • the opening width D of each microlens 21 varies randomly within a predetermined variation rate ⁇ D with reference to a predetermined reference opening width Dk.
  • ⁇ D a predetermined variation rate
  • Dk 20 [ ⁇ m]
  • ⁇ D 5 [%]
  • the optical axes 25 of all the microlenses 21 forming the microlens array 20 have substantially the same tilt angle ⁇ and substantially the same tilt direction (azimuth angle ⁇ ).
  • the surface shape of all the microlenses 21 is parabolic and rotationally symmetrical about the optical axis 25 .
  • the coefficient p and the aperture width D vary randomly around the reference values pk and Dk, the surface shape of each microlens 21 varies from the shape of the reference paraboloid. Therefore, the surface shapes of the plurality of microlenses 21 are different paraboloids.
  • each microlens 21 is deflected at substantially the same deflection angle ⁇ corresponding to the predetermined tilt angle ⁇ and substantially at the predetermined azimuth angle ⁇ . can be deflected in the same deflection direction. Therefore, the entire microlens array 20 can deflect emitted light in substantially the same deflection angle ⁇ and in substantially the same deflection direction, so that the emitted light can be favorably deflected in a desired direction.
  • the surface shape of each microlens 21 is varied by randomly varying the opening width D and the coefficient p of each microlens 21 within a predetermined range. As a result, it is possible to reduce unevenness in the intensity distribution of the diffused light due to interference and diffraction of the light emitted from the plurality of microlenses 21 .
  • the optical axis 25 tilted in the direction of the azimuth angle ⁇ is indicated by a solid arrow
  • the optical axis 25 tilted in the direction of the reference azimuth angle ⁇ k is indicated by a two-dot chain arrow.
  • the tilt angle ⁇ of the optical axis 25 with respect to the Z direction slightly fluctuates based on a predetermined reference tilt angle ⁇ k
  • the azimuth angle ⁇ representing the tilt direction of the optical axis 25 also slightly fluctuates with a predetermined reference azimuth angle ⁇ k as a reference.
  • the tilt angles ⁇ of all the microlenses 21 randomly fluctuate within a predetermined minute fluctuation width ⁇ with reference to the reference tilt angle ⁇ k.
  • the azimuth angles ⁇ of all the microlenses 21 randomly fluctuate within a predetermined minute fluctuation width ⁇ with reference to the reference azimuth angle ⁇ k.
  • the surface shape of the plurality of microlenses 21 is a hyperboloid represented by the following formula (22).
  • the radius of curvature R of each microlens 21 can also be set to a predetermined reference radius of curvature Rk, as shown in the following equation (24). It fluctuates randomly within the range of the fluctuation rate ⁇ R. As a result, the curvature radii R of the plurality of microlenses 21 have mutually different values.
  • R Rk [ ⁇ m] ⁇ R [%] (24)
  • the opening width D of each microlens 21 varies randomly within a predetermined variation rate ⁇ D with reference to a predetermined reference opening width Dk.
  • ⁇ D a predetermined variation rate
  • Dk 20 [ ⁇ m]
  • ⁇ D 5 [%]
  • the optical axes 25 of the plurality of microlenses 21 forming the microlens array 20 are tilted in mutually different directions (azimuth angles ⁇ ) at mutually different tilt angles ⁇ . ing.
  • the tilt angle ⁇ of the optical axis 25 of the plurality of microlenses 21 randomly fluctuates within a predetermined minute variation range (for example, within a minute variation width ⁇ ) with reference to a predetermined reference tilt angle ⁇ k. are doing.
  • the azimuth angle ⁇ of the optical axis 25 of the plurality of microlenses 21 also varies randomly within a predetermined minute variation range (for example, within a predetermined variation width ⁇ ) with reference to a predetermined reference azimuth angle ⁇ k. are doing.
  • the surface shapes of all the microlenses 21 are hyperboloids and rotationally symmetrical about the optical axis 25 .
  • the coefficient p and the aperture width D vary randomly around the reference values pk and Dk, the surface shape of each microlens 21 varies from the shape of the reference hyperboloid. Therefore, the surface shapes of the plurality of microlenses 21 are hyperboloids different from each other.
  • the light emitted from the plurality of microlenses 21 is deflected at substantially the same deflection angle ⁇ corresponding to the predetermined reference tilt angle ⁇ k and substantially the same corresponding to the predetermined reference azimuth angle ⁇ k. can be deflected in any deflection direction. Therefore, the entire microlens array 20 can deflect emitted light in generally the same deflection angle ⁇ and in generally the same deflection direction, so that the emitted light can be favorably deflected in a desired direction. Furthermore, not only the aperture width D and the coefficient p of each microlens 21 but also the tilt angle ⁇ and the azimuth angle ⁇ fluctuate within a predetermined fluctuation range. It is also possible to further reduce unevenness in the intensity distribution of the diffused light due to .
  • the tilt angle ⁇ of the optical axis 25 with respect to the Z direction varies randomly based on a predetermined reference tilt angle ⁇ k, and , the azimuth angle ⁇ representing the tilt direction of the optical axis 25 varies randomly.
  • the tilt angles ⁇ of all the microlenses 21 randomly fluctuate within a predetermined fluctuation width ⁇ with reference to the reference tilt angle ⁇ k.
  • the azimuth angles ⁇ of all the microlenses 21 randomly fluctuate within a relatively wide fluctuation range. In the example of FIG.
  • the surface shape of the plurality of microlenses 21 is an elliptical surface represented by the following formula (32).
  • the radius of curvature R of the microlens 21 can also be set to a predetermined reference radius of curvature Rk as shown in the following equation (34). It fluctuates randomly within the range of the fluctuation rate ⁇ R. As a result, the curvature radii R of the plurality of microlenses 21 have mutually different values.
  • R Rk [ ⁇ m] ⁇ R [%] (34)
  • the opening width D of each microlens 21 varies randomly within a predetermined variation rate ⁇ D with reference to a predetermined reference opening width Dk.
  • ⁇ D a predetermined variation rate
  • Dk 10 [ ⁇ m]
  • ⁇ D 5 [%]
  • the opening width D of each microlens 21 is represented by the following equation (35).
  • the optical axes 25 of the plurality of microlenses 21 forming the microlens array 20 are tilted in mutually different directions (azimuth angles ⁇ ) at mutually different tilt angles ⁇ . ing.
  • the tilt angle ⁇ of the optical axis 25 of the plurality of microlenses 21 randomly fluctuates within a predetermined fluctuation range (for example, within a relatively wide fluctuation width ⁇ ) with reference to a predetermined reference tilt angle ⁇ k. ing.
  • the azimuth angles ⁇ of the optical axes 25 of the plurality of microlenses 21 are also different from each other, and the azimuth angles ⁇ vary randomly within a predetermined variation range (for example, within a relatively wide variation range ⁇ ). ing.
  • the surface shape of all the microlenses 21 is an elliptical surface and rotationally symmetrical about the optical axis 25 .
  • the coefficient p and the aperture width D vary randomly around the reference values pk and Dk, the surface shape of each microlens 21 varies from the shape of the reference ellipsoid. Therefore, the surface shapes of the plurality of microlenses 21 are ellipsoidal surfaces different from each other.
  • the microlens array 20 having such a configuration, the light emitted from each microlens 21 is deflected at a deflection angle ⁇ corresponding to the tilt angle ⁇ of each optical axis 25 and azimuth angle ⁇ of each optical axis 25 . It can be deflected in the deflection direction. Therefore, the microlens array 20 as a whole can deflect emitted light in random directions at random deflection angles ⁇ around a desired angle. Therefore, since the deflection direction and the deflection angle ⁇ of the emitted light can be varied, the homogeneity of the emitted light can be improved.
  • each microlens 21 fluctuate within a predetermined fluctuation range, but also the tilt angle ⁇ and the azimuth angle ⁇ fluctuate greatly within a relatively wide fluctuation range. It is also possible to further reduce unevenness in the intensity distribution of diffused light due to interference and diffraction of light emitted from the microlens 21 .
  • the tilt angle ⁇ of the optical axis 25 with respect to the Z direction varies randomly based on a predetermined reference tilt angle ⁇ k, and , the azimuth angle ⁇ representing the tilt direction of the optical axis 25 varies randomly.
  • the tilt angles ⁇ of all the microlenses 21 randomly fluctuate within a predetermined fluctuation width ⁇ with reference to the reference tilt angle ⁇ k.
  • the azimuth angles ⁇ of all the microlenses 21 randomly fluctuate within a relatively wide fluctuation range. In the example of FIG.
  • the surface shape of the plurality of microlenses 21 is an aspherical surface represented by the following formula (42).
  • each parameter is as follows.
  • C: Curvature (C 1/R)
  • K: conic coefficient (for example, K -2)
  • a 4 : 4th order aspheric coefficient (eg A 4 2E ⁇ 5)
  • a 6 : 6th order aspheric coefficient (for example, A 6 2E ⁇ 7)
  • the radius of curvature R of each microlens 21 varies randomly within a predetermined variation rate ⁇ R with reference to a predetermined reference radius of curvature Rk.
  • ⁇ R a predetermined variation rate
  • Rk 15 [ ⁇ m]
  • ⁇ R 5 [%]
  • the curvature radius R of each microlens 21 is represented by the following equation (44).
  • the opening width D of each microlens 21 varies randomly within a predetermined variation rate ⁇ D with reference to a predetermined reference opening width Dk.
  • ⁇ D the aperture width D of each microlens 21 is represented by the following equation (45).
  • the optical axes 25 of the plurality of microlenses 21 forming the microlens array 20 are tilted in mutually different directions (azimuth angles ⁇ ) at mutually different tilt angles ⁇ . ing.
  • the surface shape of all the microlenses 21 is an aspherical surface represented by the above formula (42), and is rotationally symmetrical about the optical axis 25 .
  • the radius of curvature R and the aperture width D described above vary randomly around the reference radius of curvature Rk and the reference aperture width Dk, respectively, the surface shape of each microlens 21 fluctuates from the reference aspheric shape. are doing. Therefore, the surface shapes of the plurality of microlenses 21 are aspherical shapes different from each other.
  • each microlens 21 With the microlens array 20 having such a configuration, the light emitted from each microlens 21 is deflected at a deflection angle ⁇ corresponding to the tilt angle ⁇ of each optical axis 25 and azimuth angle ⁇ of each optical axis 25 . It can be deflected in the deflection direction. Therefore, as shown in FIG. 15, when light is received from the light source 60 to the diffuser plate 1, the reflection azimuth of the reflected light on the diffuser plate 1 is the tilt angle ⁇ and the azimuth angle ⁇ of the optical axis 25 of each microlens 21. It varies accordingly. Therefore, there is an effect that reflected diffused light with even higher uniformity can be realized.
  • FIG. 16 is a flowchart showing a microlens design method according to this embodiment.
  • the lens center coordinates pn of each microlens 21 are set on the surface of the microlens array 20 (on the XY plane).
  • the lens center coordinates pn are the coordinates of the center point 30 (see FIG. 5) of each microlens 21 on the XY plane.
  • the plurality of lens center coordinates pn are set at random positions so that the intervals between the plurality of lens center coordinates pn on the XY plane are distributed within a preset range. is preferred.
  • a plurality of lens center coordinates pn (xpn, ypn) are set on the XY plane of the unit cell 3 of the microlens array 20 whose size is set in advance.
  • a plurality of lens center coordinates pn (xpn, ypn) are arranged on the XY plane such that the intervals between the plurality of lens center coordinates pn are within a preset range.
  • the overlapping amount Ov between the microlenses 21 adjacent to each other may be adjusted.
  • the amount of overlap Ov between the microlenses 21 adjacent to each other on the XY plane falls within a predetermined allowable range (for example, a predetermined value or less).
  • a predetermined allowable range for example, a predetermined value or less.
  • the x-coordinate and y-coordinate of the lens center coordinate pn of the microlens 21 to be newly arranged, and the lens radius r are determined by random numbers.
  • the amount of overlap Ov between the planar shape of each microlens 21 already arranged and the planar shape of the newly arranged microlens 21 is calculated.
  • the overlapping amount Ov is the overlapping width of the planar shapes of the two microlenses 21, 21 adjacent to each other, and can be calculated by the following formula (50).
  • each parameter is as follows.
  • Ov amount of overlap between adjacent microlenses 21, 21 xi, yi: lens center coordinates pi of one microlens 21 ri: radius of one microlens 21 xj, yj: lens center coordinates pj of the other microlens 21 rj: radius of the other microlens 21
  • the amount of overlap Ov with the already placed microlens 21 is calculated, and if the amount of overlap Ov is within a preset allowable range, For example, a new microlens 21 is arranged. Conversely, if the calculated amount of overlap Ov is outside the allowable range (for example, if it exceeds the upper limit of the allowable range or is less than the lower limit of the allowable range), no new microlens 21 is placed. make it The permissible range is preferably obtained in advance according to the optical characteristics required for the microlens array 20 and the like.
  • the overlapping amount Ov may be adjusted within the allowable range while randomly arranging the lens center coordinates pn of the microlenses 21 on the XY plane.
  • the microlenses 21 can be arranged at random positions while overlapping each other with an appropriate overlapping amount Ov. Therefore, since it is possible to suppress the generation of flat portions that do not form lens surfaces between the adjacent microlenses 21, 21, it is possible to suppress the generation of 0th-order diffracted light that passes through the flat portions of the diffuser plate 1.
  • microlenses 21, 21 do not overlap each other excessively, the moldability and feasibility of the microlens array structure are not impaired.
  • a lens parameter is a parameter that determines the surface shape of the microlens 21 (lens surface shape).
  • the lens parameters are preferably set randomly within a preset variation range.
  • the lens surface shape is a reference aspheric surface shape rotationally symmetric about the optical axis 25, such as an ellipsoid (the surface of a spheroid whose rotation axis is in the direction of the optical axis 25), a paraboloid, a hyperboloid, or the like.
  • the lens parameters include, for example, the aperture width D (lens diameter) of the microlens 21, the radius of curvature R of the top of the microlens 21, the tilt angle ⁇ , the azimuth angle ⁇ , and the like.
  • the aperture width D and curvature radius R of each microlens 21 may be set to values that vary randomly so that the aperture width D and curvature radius R of the plurality of microlenses 21 differ from each other.
  • the lens surface shape (rotationally symmetrical reference aspheric surface shape) of the plurality of microlenses 21 is varied to obtain different aspheric surface shapes. can be set.
  • the distance d may include the distance dx in the X direction from the lens center coordinate pn on the XY plane and the distance dy in the Y direction.
  • the lens surface shape (rotationally asymmetric aspherical shape) of the plurality of microlenses 21 can be varied. , can be set to mutually different aspheric shapes.
  • the planar shape of the microlens 21 is, for example, as shown in FIG. becomes a circle as shown in .
  • the planar shape of the microlens 21 is, for example, as shown in FIG. It becomes an ellipse or a shape approximating an ellipse.
  • the set size of the lens surface shape on the XY plane for example, the aperture width D
  • the optical axis 25 of each microlens 21 is tilted at the tilt angle ⁇ with respect to the Z direction.
  • the tilt direction of the optical axis 25 is the direction defined by the azimuth angle ⁇ (see FIG. 5).
  • the lens surface shape (reference aspheric surface shape) determined in S14 is rotated about the center point 30 of each microlens 21 as the center of rotation.
  • the rotation angle at this time is the same as the inclination angle ⁇ , and the rotation direction is the direction of the azimuth angle ⁇ (see FIG. 5).
  • the center point 30, which is the center of rotation, is the origin (x, y, z) when designing the reference aspheric shape of the microlens 21 in S12 and S14.
  • the lens surface shape is tilted at the tilt angle ⁇ with respect to the Z direction and changed from the reference aspherical shape to the tilted aspherical shape.
  • the vertex of the microlens 21 moves from the vertex 28 before rotation to a new vertex 29 .
  • This new vertex 29 is the vertex of the tilted aspherical shape obtained by rotating the reference aspherical shape by the tilt angle ⁇ , and is arranged at a position shifted from the optical axis 25 tilted by the tilt angle ⁇ .
  • the optical axis 25 of the microlens 21 is tilted and the lens surface shape is rotated.
  • the principal ray 51 of the emitted light 50 is bent in a desired direction with respect to the principal ray 41 of the incident light 40 incident on the microlens 21, and the principal ray 51 of the incident light 40 is The luminous flux of the emitted light 50 can be deflected in a desired direction.
  • the parameters that define the lens surface shape are varied randomly. Furthermore, it is preferable that the plurality of microlenses 21 are arranged so as to overlap each other without gaps, and that there is no flat portion at the boundaries between adjacent microlenses 21 . As a result, it is possible to continuously arrange a plurality of microlens arrays 20 on the XY plane without gaps, and to give each microlens 21 different diffusion characteristics.
  • the microlens array 20 having such a configuration has a variety of light distribution controllability with high homogeneity, with small variations in macro light amount depending on the lens surface structure and changes in light amount due to diffracted light.
  • FIG. 22 is a flow chart showing a method for manufacturing the diffusion plate 1 according to this embodiment.
  • the base material (the base material of the master disc or the base material 10 of the diffuser plate 1) is washed (step S101).
  • the substrate may be, for example, a roll-shaped substrate such as a glass roll, or a flat substrate such as a glass wafer or a silicon wafer.
  • a resist is formed on the surface of the substrate after cleaning (step S103).
  • a resist layer can be formed using a resist using a metal oxide.
  • a resist layer can be formed on a roll-shaped substrate by spray coating or dipping a resist.
  • a resist layer can be formed on a plate-like substrate by applying various coating treatments with a resist.
  • a positive photoreactive resist may be used, or a negative photoreactive resist may be used.
  • a coupling agent may be used in order to increase the adhesion between the substrate and the resist.
  • the resist layer is exposed using a pattern corresponding to the shape of the microlens array 20 (step S105).
  • Such exposure processing includes, for example, exposure using a grayscale mask, multiple exposure by superimposing a plurality of grayscale masks, or laser exposure using a picosecond pulse laser, femtosecond pulse laser, or the like, and other known exposure methods. should be applied as appropriate.
  • the exposed resist layer is developed (S107).
  • a pattern is formed in the resist layer by such development processing.
  • a development process can be performed by using an appropriate developer according to the material of the resist layer.
  • the resist layer can be alkali-developed using an inorganic or organic alkaline solution.
  • a glass master can be manufactured by subjecting a glass substrate to glass etching using a patterned resist layer as a mask.
  • a metal master can be manufactured by performing Ni sputtering or nickel plating (NED treatment) on a patterned resist layer, forming a pattern-transferred nickel layer, and then peeling off the base material. .
  • Ni sputtering with a film thickness of about 50 nm, or nickel plating with a film thickness of 100 ⁇ m to 200 ⁇ m (for example, Ni sulfamate bath) is used to form a nickel layer onto which a resist pattern has been transferred, thereby manufacturing a metal master master disc. can do.
  • the inverted shape of the microlens array 20 is formed on the surface.
  • a soft mold is created (S113).
  • the pattern of the microlens array 20 is transferred to a glass base material, a film base material, or the like (S115).
  • the diffusion plate 1 according to the present embodiment is manufactured.
  • the diffusion plate 1 is manufactured (S115) by transfer using the soft mold after manufacturing the soft mold (S113) using the master master (S111).
  • a master master disc for example, an inorganic glass master disc
  • the diffusion plate 1 may be manufactured by imprinting using the master master disc.
  • a base material made of PET (PolyEthylene Terephthalate) or PC (PolyCarbonate) is coated with an acrylic light-curing resin, the pattern of the master is transferred to the applied acrylic light-curing resin, and the acrylic light-curing resin is exposed to UV light. By curing, the diffusion plate 1 can be manufactured.
  • the diffusion plate 1 is manufactured by directly processing the glass substrate itself, the substrate 10 is dried using a known compound such as CF 4 following the development treatment in step S107. An etching process is performed (S119), and then a protective film, an antireflection film, etc. are formed as necessary (S121), thereby manufacturing the diffuser plate 1 according to the present embodiment.
  • a known compound such as CF 4 following the development treatment in step S107.
  • An etching process is performed (S119), and then a protective film, an antireflection film, etc. are formed as necessary (S121), thereby manufacturing the diffuser plate 1 according to the present embodiment.
  • the manufacturing method shown in FIG. 22 is merely an example, and the manufacturing method of the diffusion plate is not limited to the above example.
  • the diffuser plate 1 as described above can be appropriately mounted on various devices that need to diffuse light in order to realize its function.
  • Examples of such devices include display devices such as various displays (for example, LED and organic EL displays), projection devices such as projectors, and various lighting devices.
  • the diffuser plate 1 can be applied to a backlight of a liquid crystal display device, a lens integrated with a diffuser plate, and the like, and can also be used for light shaping.
  • the diffusion plate 1 can also be applied to transmission screens, Fresnel lenses, reflection screens, etc. of projection devices.
  • the diffusion plate 1 can also be applied to various lighting devices used for spot lighting, base lighting, etc., various special lighting, various screens such as intermediate screens and final screens, and the like.
  • the diffusion plate 1 can also be applied to applications such as diffusion control of light source light in optical devices, such as light distribution control of LED light source devices, light distribution control of laser light source devices, and incident light distribution to various light valve systems. It can also be applied to control and the like.
  • the device to which the diffusion plate 1 is applied is not limited to the above application examples, and can be applied to any known device as long as it utilizes light diffusion.
  • the diffusion plate 1 according to the present embodiment can be mounted in optical equipment such as various illumination optical systems, image projection optical systems, or measurement detection sensing optical systems.
  • the diffusion plate 1 having the microlens array 20 has been described above.
  • the optical axis 25 of the microlens 21 having an aspherical shape is inclined at an inclination angle ⁇ of more than 0° with respect to the normal direction (Z direction) of the substrate 10 of the diffusion plate 1. ing.
  • the aspherical shape of the microlens 21 is also rotated about the center point 30 of the microlens 21 by the tilt angle ⁇ , forming a tilted aspherical shape.
  • each microlens 21 is arranged at random positions on the surface (XY plane) of the substrate 10 .
  • the lens parameters (eg, aperture width D, radius of curvature R) that determine the aspherical shape of each microlens 21 are determined based on predetermined reference values (eg, reference aperture width Dk, reference radius of curvature Rk). (for example, fluctuation rates ⁇ D and ⁇ R).
  • predetermined reference values eg, reference aperture width Dk, reference radius of curvature Rk.
  • fluctuation rates ⁇ D and ⁇ R fluctuation rates
  • the microlens array 20 uses the microlenses 21 having the tilted aspheric shape with the optical axis 25 tilted as described above as the minimum structural unit.
  • a plurality of microlenses 21 having mutually different inclined aspherical shapes are densely and randomly arranged in the plane of the microlens array 20 .
  • the microlens array 20 having such a configuration bends the principal ray 51 of the emitted light 50 (diffused light) transmitted through the diffusion plate 1 in a desired direction, and converts the emitted light 50 (diffused light) into the incident light. 40 can be deflected in any desired direction.
  • the macroscopic overall transmission optical axis was determined by the effect of transmission refraction of the diffuser plate.
  • the optical axis 25 itself of the microlens 21 is tilted at the tilt angle ⁇ to rotate the aspherical shape, so that the luminous flux of the emitted light 50 is normally It is possible to deflect in a direction different from the effect of transmissive refraction.
  • the degree of freedom in designing the optical axis direction of the incident light 40 and the emitted light 50 with respect to the diffuser plate 1 can be expanded, and at the same time, the size of the optical equipment system in which the diffuser plate 1 is mounted can be reduced, and the optical functions such as visibility can be improved. can be optimized.
  • the microlens 21 according to the present embodiment may have a rotationally symmetrical shape about the optical axis 25 , that is, an isotropic aspherical shape around the optical axis 25 .
  • a rotationally symmetrical shape about the optical axis 25
  • the microlens 21 may have a rotationally asymmetrical shape about its optical axis 25, that is, an aspherical shape having anisotropy in a specific direction. It may be an aspherical shape that changes shape.
  • each microlens 21 may vary randomly within predetermined fluctuation ranges ⁇ and ⁇ with reference to a predetermined reference tilt angle ⁇ k and reference azimuth angle ⁇ k.
  • the tilt angles ⁇ and the azimuth angles ⁇ of the plurality of microlenses 21 may not be the same, and may vary randomly within predetermined small variation widths ⁇ and ⁇ .
  • noise caused by the diffracted light can be suppressed in the beam of the output light 50 that has been deflected, and unevenness in the intensity distribution of the beam of the output light 50 can be suppressed, and the homogeneity of the beam of the output light 50 can be improved.
  • the direction of deflection of the emitted light 50 by the plurality of microlenses 21 may be the same for the entire microlens array 20 or may be different for each region of the microlenses 21 .
  • the deflection angle ⁇ of the emitted light 50 by the plurality of microlenses 21 may be the same angle for the entire microlens array 20 or may be different for each region of the microlenses 21 .
  • the microlens array 20 as a whole can deflect the luminous flux of the emitted light 50 in the same deflection direction and at the same deflection angle ⁇ .
  • the deflection direction and the deflection angle ⁇ are different for each region of the microlens array 20
  • each region of the microlens array 20 can deflect the luminous flux of the emitted light 50 with a different deflection direction and deflection angle ⁇ . can be done.
  • the same plane of the microlens array 20 includes a plurality of regions with different deflection directions and deflection angles ⁇ .
  • a single microlens array 20 can deflect emitted light in various deflection modes. As a result, for example, it is possible to efficiently utilize a luminous flux of diffused light over a wide range, and to improve the visibility of the projected image by controlling the principal ray in the optical projection system.
  • the diffuser plate 1 having the microlenses 21 having the inclined aspherical surface shape according to the present embodiment can be manufactured by, for example, imprint processing using a master plate having the concave-convex structure of the microlenses 21 .
  • the master can be manufactured by high-precision drawing exposure or stepper exposure using laser light or a controlled light source, and photolithography techniques such as etching.
  • the master can be manufactured by transferring a structural surface molded by lithography by electroforming, or can be manufactured as an inorganic device by glass etching.
  • the master can be manufactured by precision machining technology.
  • a product of the diffuser plate 1 according to the present embodiment may be provided, for example, as an inorganic device by glass etching.
  • the diffuser plate 1 may be provided as an organic imprint film replicated from a master, for example.
  • the product of the diffusion plate 1 can be provided as a transfer film product or a member surface transfer product.
  • the surface of each microlens had an aspherical shape expressed by an aspherical formula using the conic coefficient K.
  • the conic coefficient K was set to a positive value (K>0)
  • the aspherical shape of each microlens was set to a longitudinally elongated elliptical surface convex in the Z direction.
  • the aperture width D of each microlens was randomly varied within a predetermined variation rate ⁇ D with reference to a predetermined reference aperture width Dk.
  • the radius of curvature R of each microlens was varied randomly within a range of a predetermined variation rate ⁇ R with a predetermined reference radius of curvature Rk as a reference.
  • Microlens arrays according to Examples and Comparative Examples were designed by densely and randomly arranging a plurality of microlenses having such aspherical shapes on the XY plane of the substrate. A simulation was performed on the state of diffused light distribution by the microlens array when collimated light in the normal direction (Z direction) was incident on the microlens array as the incident light.
  • diffusion plates according to Examples and Comparative Examples were actually manufactured by the manufacturing method described below.
  • a photoreactive resist was applied to one surface (principal surface) of the glass base material with a resist thickness of 5 ⁇ m to 20 ⁇ m.
  • a positive photoreactive resist such as PMER-LA900 (manufactured by Tokyo Ohka Kogyo Co., Ltd.) or AZ4620 (registered trademark) (manufactured by AZ Electronic Materials) was used.
  • a pattern was drawn on the resist on the glass substrate with a laser drawing device using a laser with a wavelength of 405 nm, and the resist layer was exposed.
  • the resist layer may be exposed by subjecting the resist on the glass substrate to mask exposure using a stepper exposure apparatus using g-line.
  • a pattern was formed in the resist by developing the resist layer.
  • a tetramethylammonium hydroxide (TMAH) solution such as NMD-W (manufactured by Tokyo Ohka Kogyo Co., Ltd.) or PMER P7G (manufactured by Tokyo Ohka Kogyo Co., Ltd.) was used.
  • TMAH tetramethylammonium hydroxide
  • a diffusion plate was manufactured by etching the glass substrate using the patterned resist. Specifically, the diffusion plate was manufactured by forming a resist pattern on the glass substrate by glass etching using Ar gas and CF 4 gas.
  • Table 1 shows the design conditions of the surface structure of the microlens array and the deflection function of the emitted light by the diffuser plates of Examples 1 and 2 and Comparative Examples 1 and 2 designed and manufactured as described above. Evaluation results are shown.
  • a plurality of microlenses having D and R set in this manner were densely and randomly arranged on the surface (on the XY plane) of the substrate of the microlens array to design the microlenses.
  • the overlapping amount Ov between the microlenses was set to 30 ⁇ m.
  • the height Zmax of the vertex of the microlens was 11 ⁇ m.
  • Comparative Example 1 the tilt angle ⁇ of the optical axis of the microlens was 0°, and the optical axis of the microlens and the lens surface shape were not tilted with respect to the normal direction (Z direction) of the microlens array. That is, in Comparative Example 1, the optical axes of all the microlenses were parallel to the Z direction, and the lens surface shape was a non-inclined reference aspherical shape.
  • Comparative Example 2 a microlens was designed and manufactured in the same manner as in Comparative Example 1, except that the conic coefficient K of the reference aspheric surface shape of the microlens was +1.0. Zmax was 12.4 ⁇ m.
  • the tilt angle ⁇ of the optical axis of the microlens was also 0°, and the optical axis of the microlens and the lens surface shape were not tilted with respect to the normal direction (Z direction) of the microlens array.
  • the azimuth angle ⁇ representing the tilt direction was set to 0°, and the optical axes of all the microlenses were tilted in the positive direction of the X axis.
  • Example 2 microlenses were designed and manufactured in the same manner as in Comparative Example 2, except that the optical axes of the microlenses and the lens surface shape were inclined with respect to the normal direction (Z direction) of the microlens array. . Zmax was 16.4 ⁇ m.
  • the azimuth angle ⁇ representing the tilt direction was set to 0°, and the optical axes of all the microlenses were tilted in the positive direction of the X axis.
  • “A” represents the surface shape of the microlens array of the entire computer generated region (unit cell 3 in FIG. 1). is a bitmap data image showing "B” is a graph showing the simulation results of the illuminance distribution of diffused light projected onto the screen at a distance of 100 mm from the diffusion plate (horizontal axis: horizontal coordinate position [mm] of the screen, vertical axis: illuminance). be.
  • "C” is an image showing the simulation result of the luminance distribution of diffused light on the surface of the screen (horizontal axis: horizontal coordinate position of the screen [mm], vertical axis: vertical coordinate position of the screen [mm] ).
  • “D” indicates the diffusion angle (full width at half maximum: FWHM) in the illuminance distribution of "B".
  • 24 and 25 according to Examples 1 and 2 show the deflection angle (Shift1) of the peak region in the luminance distribution of "B” and the deflection angle (Shift2) of the FWHM (full width at half maximum). is also shown.
  • the microlens arrays according to Examples 1 and 2 diffused light is deflected in a specific direction (X-axis positive direction) with respect to the normal direction.
  • the deflection angles ⁇ of Examples 1 and 2 are about 3° and about 4°, respectively, and the microlens array has a clear deflection function.
  • the direction of the principal ray of the emitted light is the same as the direction of the principal ray of the incident collimated light. , both of which are normal directions.
  • the light distribution of the emitted light (diffused light) is isotropic with respect to the normal direction, and has rotationally symmetrical characteristics with the normal direction as the central axis.
  • the direction of the principal ray of the emitted light (diffused light) is not bent with respect to the normal direction, and the luminous flux of the emitted light (diffused light) is directed in a specific direction. not biased.
  • the direction of the principal ray of the emitted light is the direction of the principal ray of the incident collimated light (that is, normal line direction). That is, the luminous flux of emitted light (diffused light) is bent in a deflection direction (a direction represented by the deflection angle ⁇ ) corresponding to the tilt direction of the optical axis of the microlens, and is deflected in the deflection direction.
  • the light distribution of the emitted light (diffused light) is anisotropic in the polarization direction and has rotationally asymmetric characteristics with respect to the normal direction.
  • the emitted light can be favorably deflected by the microlens array including a plurality of microlenses with tilted optical axes. It was confirmed that the deflection angle ⁇ of the emitted light (diffused light) at this time was about 3° and about 4°.
  • Example 3 an imprint film according to Example 3 will be described.
  • an imprint film was manufactured using the diffusion plate according to Example 1 as a master.
  • a diffuser plate made of an inorganic material made of a substrate glass was manufactured by dry-etching the exposed resist pattern formed on the substrate glass.
  • This diffuser plate corresponds to the diffuser plate of the first embodiment, and is a diffusion light distribution device having a function of deflecting emitted light.
  • the surface structure of the microlens array of the master is transferred to an organic resin to form an imprint film according to Example 3, that is, an organic diffusion plate. manufactured.
  • FIG. 27 is a graph (horizontal axis: diffusion angle (deg), vertical axis: relative luminance (a.u.)) showing the light distribution characteristics of diffused light by the imprint film according to Example 3.
  • FIG. The light distribution characteristics of the graph of "0deg" shown in FIG. It represents the light distribution characteristics of the azimuth perpendicular to the azimuth where there is no
  • the diffused light is deflected in a specific direction, and the deflection angle ⁇ is about 4°.
  • the imprint film (organic diffuser plate) according to Example 3 was used, the emitted light (diffused light) can be properly deflected.
  • ⁇ Preferred range of tilt angle ⁇ > a computer changes the tilt angle ⁇ of the optical axis of the microlenses in the range of 30° to 90° to generate a plurality of types of microlens arrays, The result of evaluating the preferable range of ⁇ will be described.
  • 28 and 29 are bitmap data images showing the surface shape of the microlens array over one generation area (unit cell 3 in FIG. 1) generated by the computer under the following design conditions.
  • a computer generated a plurality of types of microlens arrays under the following design conditions.
  • the tilt angle ⁇ of the optical axis of the microlens was varied in the range of 30° to 90°. , all under the same conditions.
  • Dk 60 ⁇ m
  • Rk 50 ⁇ m
  • ⁇ D ⁇ 10%
  • the tilt angle ⁇ is 70° or more
  • the lens surface shape is excessively tilted, resulting in significant anisotropy in the tilt direction.
  • the lens surface shape collapsed, and the moldability and feasibility of the microlens array structure decreased. Therefore, in order to ensure moldability of the microlenses, feasibility of the microlens array structure, clear manifestation of the deflection function by the microlens array, optical characteristics, etc., the tilt angle ⁇ should be 60° or less. was confirmed to be preferable.
  • the tilt angle ⁇ exceeds 45°, diffused light noise is likely to occur depending on the shape of the tilted microlens. Therefore, it was confirmed that the tilt angle ⁇ is preferably 45° or less in order to reduce the noise of the diffused light caused by the microlenses.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Optical Elements Other Than Lenses (AREA)
  • Projection Apparatus (AREA)

Abstract

Le problème décrit par la présente invention est de dévier un faisceau lumineux de lumière émise vers une direction souhaitée. La solution selon l'invention porte sur une plaque de diffuseur de type à réseau de microlentilles, ladite plaque de diffuseur comprenant un substrat et un réseau de microlentilles configuré à partir d'une pluralité de microlentilles qui sont disposées de manière aléatoire dans un plan XY sur au moins une surface du substrat, les surfaces des microlentilles ayant une forme asphérique, et les axes optiques des microlentilles étant inclinés d'un angle d'inclinaison α supérieur ou égal à 1° par rapport à la direction Z, qui est la direction normale par rapport à ladite surface du substrat.
PCT/JP2022/034068 2021-09-17 2022-09-12 Plaque de diffuseur, dispositif d'affichage, dispositif de projection et dispositif d'éclairage WO2023042798A1 (fr)

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JP2011215464A (ja) * 2010-04-01 2011-10-27 Toppan Printing Co Ltd レンズシート、バックライトユニット、及び画像表示装置
JP2015169804A (ja) * 2014-03-07 2015-09-28 株式会社リコー レンズアレイ、画像表示装置、及び移動体
WO2016052359A1 (fr) * 2014-09-30 2016-04-07 旭硝子株式会社 Écran pour projection de lumière d'image et système d'affichage
JP2016517038A (ja) * 2013-03-25 2016-06-09 スリーエム イノベイティブ プロパティズ カンパニー 複合プリズムを備えた両面フィルム
JP2016191839A (ja) * 2015-03-31 2016-11-10 旭硝子株式会社 光学素子、投影装置および計測装置
JP2017026662A (ja) * 2015-07-16 2017-02-02 デクセリアルズ株式会社 拡散板、表示装置、投影装置及び照明装置
WO2017188225A1 (fr) * 2016-04-27 2017-11-02 株式会社クラレ Plaque de diffusion et dispositif de projecteur de type à projection
JP2021071721A (ja) * 2019-10-25 2021-05-06 デクセリアルズ株式会社 拡散板、表示装置、投影装置及び照明装置

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Publication number Priority date Publication date Assignee Title
JP2011215464A (ja) * 2010-04-01 2011-10-27 Toppan Printing Co Ltd レンズシート、バックライトユニット、及び画像表示装置
JP2016517038A (ja) * 2013-03-25 2016-06-09 スリーエム イノベイティブ プロパティズ カンパニー 複合プリズムを備えた両面フィルム
JP2015169804A (ja) * 2014-03-07 2015-09-28 株式会社リコー レンズアレイ、画像表示装置、及び移動体
WO2016052359A1 (fr) * 2014-09-30 2016-04-07 旭硝子株式会社 Écran pour projection de lumière d'image et système d'affichage
JP2016191839A (ja) * 2015-03-31 2016-11-10 旭硝子株式会社 光学素子、投影装置および計測装置
JP2017026662A (ja) * 2015-07-16 2017-02-02 デクセリアルズ株式会社 拡散板、表示装置、投影装置及び照明装置
WO2017188225A1 (fr) * 2016-04-27 2017-11-02 株式会社クラレ Plaque de diffusion et dispositif de projecteur de type à projection
JP2021071721A (ja) * 2019-10-25 2021-05-06 デクセリアルズ株式会社 拡散板、表示装置、投影装置及び照明装置

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