WO2021079923A1 - Plaque de diffusion, dispositif d'affichage, dispositif de projection et dispositif d'éclairage - Google Patents

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

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Publication number
WO2021079923A1
WO2021079923A1 PCT/JP2020/039657 JP2020039657W WO2021079923A1 WO 2021079923 A1 WO2021079923 A1 WO 2021079923A1 JP 2020039657 W JP2020039657 W JP 2020039657W WO 2021079923 A1 WO2021079923 A1 WO 2021079923A1
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WIPO (PCT)
Prior art keywords
microlens
microlenses
shape
curvature
grid
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PCT/JP2020/039657
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English (en)
Japanese (ja)
Inventor
有馬　光雄
正之 石渡
駿介 金杉
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デクセリアルズ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Priority claimed from JP2020175853A external-priority patent/JP2021071721A/ja
Application filed by デクセリアルズ株式会社 filed Critical デクセリアルズ株式会社
Priority to EP20878757.2A priority Critical patent/EP4027177A4/fr
Priority to US17/766,950 priority patent/US20240077658A1/en
Priority to CN202080072883.0A priority patent/CN114556168A/zh
Publication of WO2021079923A1 publication Critical patent/WO2021079923A1/fr

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    • 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
    • G02B3/00—Simple or compound lenses
    • G02B3/02—Simple or compound lenses with non-spherical faces
    • G02B3/06—Simple or compound lenses with non-spherical faces with cylindrical or toric faces
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/02—Diffusing elements; Afocal elements

Definitions

  • the present invention relates to a diffuser, a display device, a projection device and a lighting device.
  • a diffuser plate that diffuses incident light in a desired direction is used.
  • the diffuser plate is widely used in various devices such as a display device such as a display, a projection device such as a projector, and various lighting devices.
  • a microlens array type diffuser in which a plurality of microlenses having a size of about several tens of ⁇ m are arranged is known.
  • Patent Document 1 in a diffusion plate in which a plurality of microlenses are regularly arranged in a rectangular lattice pattern on a main surface, a plurality of microlenses having different cross-sectional shapes and having no axis of symmetry. Is described to be used. Further, Patent Document 2 describes that the lens apex positions of a plurality of microlenses arranged in a rectangular grid pattern are arranged so as to be offset from the grid points of the reference grid.
  • Patent Document 1 in an array structure in which a plurality of microlenses having no target axis and having different cross-sectional shapes are regularly arranged in a rectangular lattice pattern, between microlenses adjacent to each other.
  • the unevenness of the intensity distribution of the diffused light is reduced only by the phase change of the light. Therefore, the effect of uniformly distributing the diffused light in the two directions orthogonal to each other of the rectangular lattice is limited.
  • Patent Document 2 in an array structure regularly arranged in a rectangular lattice shape, a arrangement having high homogeneity in two directions of the rectangular lattice can be obtained only by shifting the apex positions of each microlens. Optical control could not be realized.
  • an object of the present invention is to suppress unevenness of luminance distribution in two directions of microlenses arranged in a rectangular lattice pattern and to distribute light.
  • the purpose is to improve the homogeneity of the lens.
  • the grid spacing Wx in the X direction randomly fluctuates at a volatility ⁇ Wx within ⁇ 10% to ⁇ 50% with reference to the reference grid spacing Wx_k.
  • the grid spacing Wy in the Y direction may be randomly changed at a volatility ⁇ Wy within ⁇ 10% to ⁇ 50% with reference to the reference grid spacing Wy_k.
  • the radius of curvature Rx of the microlenses arranged in the X direction in the X direction varies from each other.
  • the radius of curvature Ry of the microlenses arranged in the Y direction in the Y direction may be made to fluctuate with each other.
  • the radius of curvature Rx in the X direction randomly fluctuates at a volatility ⁇ Rx within ⁇ 10% to ⁇ 50% with reference to the reference radius of curvature Rx_k.
  • the radius of curvature Ry in the Y direction may be randomly changed at a volatility ⁇ Ry within ⁇ 10% to ⁇ 50% with reference to the reference radius of curvature Ry_k.
  • the grid spacing Wx in the X direction randomly fluctuates at a volatility ⁇ Wx within ⁇ 10% to ⁇ 50% with reference to the reference grid spacing Wx_k.
  • the grid spacing Wy in the Y direction randomly fluctuates at a volatility ⁇ Wy within ⁇ 10% to ⁇ 50% with reference to the reference grid spacing Wy_k.
  • the reference grid spacing Wx_k, Wy_k and the reference curvature radii Rx_k, Ry_k satisfy the following relational expressions (A) and (B).
  • the diffusion angle (full width at half maximum) by the diffusion plate may be 20 ° or less.
  • the plane positions of the vertices of the microlenses arranged in the X direction and the Y direction may be eccentric from the center point of the rectangular lattice.
  • the distances in the X and Y directions from the center point of the rectangular lattice to the plane position of the apex of the eccentric microlens are defined as the eccentric amount Ecx and the eccentric amount Ecy, respectively, and the lattice intervals Wx and Wy of the rectangular lattice.
  • the ratios of the eccentricity Ecx and Ecy to the eccentricity are the eccentricity ⁇ Ecx and the eccentricity ⁇ Ecy, respectively.
  • the plane position of the apex of the microlens may be randomly eccentric with eccentricity ratios ⁇ Ecx and ⁇ Ecy within ⁇ 10% to ⁇ 50%.
  • the height positions of the vertices of the plurality of microlenses arranged in the X direction and the Y direction may be different from each other.
  • microlenses arranged in the X direction and the Y direction may be arranged continuously without any gaps between them.
  • the boundary lines of the microlenses adjacent to each other may include straight lines and curved lines.
  • the microlens array is composed of a plurality of unit cells, which is a basic arrangement pattern of the microlens.
  • the microlens array may be configured by arranging the plurality of unit cells without gaps while maintaining the continuity of the microlenses at the boundary portion between the plurality of unit cells.
  • the surface shape of the microlens may be a spherical shape or an aspherical shape having anisotropy in the X direction or the Y direction.
  • a display device including the above diffusion plate is provided.
  • a projection device including the above diffusion plate is provided.
  • a lighting device including the above diffusion plate is provided.
  • the present invention it is possible to suppress unevenness of the luminance distribution and improve the homogeneity of the light distribution in the two directions of the microlenses arranged in a rectangular grid pattern.
  • FIG. 1 It is a perspective view which shows the curved surface of the torus shape which concerns on this embodiment. It is a flowchart which shows the design method of the microlens which concerns on this embodiment. It is explanatory drawing which shows the rectangular grid generated in the grid generation step which concerns on the same embodiment. It is explanatory drawing which shows the rectangular grid generated in the grid eccentricity step which concerns on the same embodiment. It is explanatory drawing which shows the plurality of microlenses generated in the lens generation step which concerns on this embodiment. It is an image showing a lens pattern designed by the design method which concerns on the same embodiment. It is a flowchart which shows the manufacturing method of the diffusion plate which concerns on this embodiment. It is explanatory drawing about the diffusion plate which concerns on Comparative Example 1.
  • FIG. 1 shows the manufacturing method of the diffusion plate which concerns on this embodiment.
  • the diffusing plate according to the present embodiment described in detail below is a microlens array type diffusing plate having a homogeneous light diffusing function.
  • a diffuser has a microlens array formed on an XY plane on at least one surface (main surface) of the substrate.
  • the microlens array is composed of a plurality of microlenses arranged and expanded in a rectangular grid pattern.
  • the microlens has a convex structure (convex lens) or a concave structure (concave lens) having a light diffusing function, and has a lens diameter of about several tens of ⁇ m.
  • a plurality of microlenses are arranged in a rectangular grid shape (matrix shape) with reference to a rectangular grid having irregularities.
  • a rectangular grid having this irregularity a plurality of grid spacing Wx in the X direction (row direction) randomly fluctuates and differ from each other, and a plurality of grid spacing Wy in the Y direction (column direction) also randomly fluctuates. It fluctuates and is different from each other.
  • the radii of curvature Rx and Ry of the plurality of microlenses arranged in the X and Y directions fluctuate randomly (irregularly) so as to be different from each other.
  • the plane position of the apex of each microlens randomly fluctuates (eccentricity) so as to deviate from the center point of the rectangular lattice.
  • the height positions of the vertices of the plurality of microlenses in the Z direction also fluctuate randomly and are different from each other.
  • the surface shape of the plurality of microlenses developed in a rectangular grid shape can be changed. It fluctuates randomly and has different shapes.
  • the three-dimensional surface structure of the microlens array with high randomness is realized by randomly changing each variable element of the plurality of microlenses.
  • it is possible to control the phase superposition state of the light emitted from each microlens.
  • a surface structure of a diffuser plate capable of controlling the cutoff property of the intensity distribution.
  • a plurality of microlenses are arranged on the XY plane with reference to an irregular rectangular grid having different grid spacings Wx and Wy.
  • a plurality of microlens arrays can be continuously arranged on the surface of the diffuser without any gaps while ensuring the randomness of the surface shape of each microlens. Therefore, since the flat portion can be eliminated as much as possible at the boundary portion of the adjacent microlenses, the unevenness of the intensity distribution of the diffused light can be further reduced, and the homogeneity of the light distribution in the two directions (X and Y directions) can be further improved. Can be improved.
  • FIG. 1 is an explanatory diagram schematically showing the diffusion plate 1 according to the present embodiment.
  • the diffuser plate 1 is a microlens array type diffuser plate in which a microlens array composed of a plurality of microlenses (single lenses) is arranged on a substrate.
  • the microlens array of the diffuser plate 1 is composed of a plurality of unit cells 3.
  • the unit cell 3 is a basic arrangement pattern of the microlens.
  • a plurality of microlenses are arranged on the surface of each unit cell 3 in a predetermined layout pattern (arrangement pattern).
  • FIG. 1 shows an example in which the shape of the unit cell 3 constituting the diffusion plate 1 is rectangular, particularly square.
  • the shape of the unit cell 3 is not limited to the example shown in FIG. 1, and 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.
  • 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 according to the present embodiment is not particularly limited, and the diffusion plate 1 may be composed of one unit cell 3 or from a plurality of unit cells 3. It may be configured.
  • the unit cells 3 having different surface structures may be repeatedly arranged, or the unit cells 3 having the same surface structure may be repeatedly arranged.
  • the layout pattern (arrangement pattern) of the plurality of microlenses provided in the unit cell 3 is the unit cell 3. It is continuous in the array direction (in other words, the array array direction).
  • the microlens array is configured by arranging the unit cells 3 without gaps while maintaining the continuity of the microlenses at the boundary portion between the plurality of unit cells 3.
  • the continuity of the microlens means the microlens located on the outer edge of one unit cell 3 and the microlens located on the outer edge of the other unit cell 3 among the two adjacent unit cells 3.
  • the lenses are continuously connected without any deviation of the plane shape or steps in the height direction.
  • the unit cells 3 (basic structure) of the microlens array are arranged without gaps while maintaining the continuity of the boundaries, thereby forming the microlens array. ..
  • the unit cells 3 basic structure of the microlens array
  • FIG. 2 is an enlarged plan view and an enlarged cross-sectional view schematically showing the configuration of the diffusion plate 1 according to the present embodiment.
  • FIG. 3 is an enlarged cross-sectional view schematically showing the vicinity of the boundary of the microlens 21 according to the present embodiment.
  • FIG. 4 is a plan view schematically showing the planar shape (outer shape) of the microlens 21 when the microlens 21 is viewed in a plan view from a direction perpendicular to the surface of the base material 10.
  • the diffuser plate 1 includes a base material 10 and a microlens array 20 formed on the surface of the base material 10.
  • the base material 10 is a substrate for supporting the microlens array 20.
  • the base material 10 may be in the form of a film or in the form of a plate.
  • the base material 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 of the device on 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 formed 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 a wavelength band corresponding to visible light.
  • the base material 10 is, for example, polymethylmethacrylate (PMMA), polyethylene terephthalate (PET), polycarbonate (PC), cyclic olefin copolymer (Cyclo Olefin Polymer: COC), cyclic olefin. It may be formed of a known resin such as Olefin Polymer (COP) and Triacetyl cellulose (TAC). Alternatively, the base material 10 may be formed of known optical glass such as quartz glass, borosilicate glass, and white plate glass.
  • PMMA polymethylmethacrylate
  • PET polyethylene terephthalate
  • PC polycarbonate
  • COC cyclic olefin copolymer
  • COC cyclic olefin
  • It may be formed of a known resin such as Olefin Polymer (COP) and Triacetyl cellulose (TAC).
  • the base material 10 may be formed 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 (main surface) of the base material 10.
  • the microlens array 20 is an aggregate of a plurality of microlenses 21 (single lenses) arranged on the surface of the base material 10.
  • the microlens array 20 is formed on one surface of the base material 10.
  • the present invention is not limited to this, and the microlens array 20 may be formed on both main surfaces (front surface and back surface) of the base material 10.
  • 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 microlens 21 may have a concave structure (concave lens) formed so as to be depressed in the thickness direction of the diffuser plate 1, or a convex structure (convex lens) formed so as to project in the thickness direction of the diffuser plate 1. It may be.
  • the microlens 21 has a concave structure (concave lens) as shown in FIG. 2 will be described, but the present invention is not limited to such an example.
  • the microlens 21 may have a convex structure (convex lens) depending on the desired optical characteristics of the diffuser plate 1.
  • each microlens 21 is not particularly limited as long as it is a curved surface shape including a curved surface component.
  • the surface shape of the microlens 21 may be, for example, a spherical shape containing only a spherical component, an aspherical shape containing only a spherical component and an aspherical component, or a spherical shape containing only an aspherical component. It may have an aspherical shape.
  • the plurality of microlenses 21 are densely arranged so as to be adjacent to each other without a gap. In other words, it is preferable that the plurality of microlenses 21 are continuously arranged so that there is no gap (flat portion) at the boundary portion between the microlenses 21 adjacent to each other.
  • the incident light is not scattered on the surface of the diffuser plate 1. It is possible to suppress a component that is transmitted as it is (hereinafter, also referred to as a "0th-order transmitted light component"). As a result, the diffusion performance can be further improved by the microlens array 20 in which the plurality of microlenses 21 are arranged so as to be adjacent to each other without a gap.
  • the filling rate of the microlens 21 on the base material 10 is preferably 90% or more, and more preferably 100%.
  • the filling rate is the ratio of the area of the portion occupied by the plurality of microlenses 21 on the surface of the base material 10.
  • the surface of the microlens array 20 is formed of curved surface components and contains almost no flat surface components.
  • the vicinity of the inflection point at the boundary between adjacent microlenses 21 may become substantially flat. obtain.
  • the width of the region near the inflection point (the width of the boundary line between the microlenses 21) that becomes substantially flat at the boundary between the microlenses 21 is preferably 1 ⁇ m or less.
  • the plurality of microlenses 21 are not randomly (irregularly) arranged, but as shown in FIG. 2, the grid spacing is in the X direction and the Y direction. It is arranged in a somewhat regular manner (hereinafter referred to as "quasi-regular") with reference to an irregular rectangular lattice (see FIG. 5) in which Wx and Wy are fluctuated.
  • quadsi-regular means that there is no substantial regularity in the arrangement of microlenses in any region of the microlens array. However, even if there is some regularity in the arrangement of the microlenses in the minute region, the one in which the arrangement of the microlenses does not have regularity in the entire arbitrary region is included in "irregularity".
  • the plurality of microlenses 21 are arranged semi-regularly with reference to a rectangular grid having irregularities.
  • the surface shape and the planar shape of the microlens 21 are randomly changed.
  • the planar shape (outer shape) of the microlens 21 has a shape close to a substantially rectangular shape as a whole, but has a perfect rectangular shape (square shape or rectangular shape) corresponding to a rectangular grid. )is not it.
  • the planar shape of the microlens 21 has a shape close to a substantially polygon having four or more vertices, such as a substantially quadrangle, a substantially pentagon, and a substantially hexagon.
  • the surface shape (three-dimensional curved surface shape) and the planar shape (shape projected onto the XY plane of the base material 10) of the plurality of microlenses 21 are different from each other.
  • the reason why each microlens 21 has a shape that is irregularly collapsed from a rectangular shape is that the radius of curvature Rx, Ry, the aperture diameter Dx, Dy, and the plane position of the lens apex of each microlens 21. This is because the height position and the like fluctuate randomly within a range of a predetermined fluctuation rate.
  • the details of the semi-regular arrangement method of the microlens 21 based on the rectangular grid according to the present embodiment will be described later (see FIGS. 5 to 7).
  • the radii of curvature Rx and Ry and the aperture diameters Dx and Dy of each microlens 21 vary randomly and have variations.
  • the aperture diameters Dx and Dy of the microlens 21 correspond to the lens diameter of a single lens.
  • the phase distribution of the optical aperture of each microlens 21 differs depending on the orientation.
  • a plurality of microlenses 21 are continuously arranged on the surface of the base material 10 so as to overlap each other, and the radii of curvature Rx and Ry and the aperture diameters Dx and Dy (lens diameter) of the respective microlenses 21 vary.
  • the shapes (surface shape and planar shape) of the plurality of microlenses 21 are not the same as each other. Therefore, the plurality of microlenses 21 come to have various shapes as shown in FIG. 2, and many of them do not have symmetry.
  • the curvature radius of the microlens 21A is R A
  • the curvature radius of the microlens 21B adjacent to the microlenses 21A is a state that it is R B ( ⁇ R A) resulting Will be.
  • the radius of curvature R A of the microlenses 21 which are adjacent to each other, if the R B are different from each other, the boundary between the microlenses 21 which are adjacent to each other is not composed of only straight lines, configured to include a curve in at least a part Will be.
  • the outline of the planar shape of the microlens 21 (the microlens 21 and the microlens 21).
  • the boundary line between the plurality of adjacent microlenses 21) includes a plurality of curves having different curvatures from each other and a straight line.
  • the boundary line of the microlens 21 includes a plurality of curves having different curvatures from each other, the regularity of the boundary between the microlenses 21 is further broken, so that the diffraction component of the diffused light can be further reduced.
  • FIG. 5 is a plan view schematically showing the arrangement of the irregular rectangular lattice-shaped microlenses 21 according to the present embodiment.
  • FIG. 6 is an explanatory view showing an example in which the surface shape of the microlens 21 is changed from the state of FIG.
  • FIG. 7 is an explanatory view showing an example in which the plane position of the apex 22 of the microlens 21 is eccentric from the state of FIG.
  • microlens array 20 in which a plurality of microlenses 21 having the above-mentioned characteristics are arranged can be realized by the arrangement method according to the present embodiment described below.
  • a reference state (hereinafter, also referred to as "initial arrangement state") in which a plurality of microlenses 21 having a reference shape are arranged semi-regularly in a rectangular grid pattern is set for the time being.
  • the shape of the microlens 21 that is, the radius of curvature Rx, Ry, the aperture diameter Dx, Dy, etc.
  • the position of the apex 22 of the microlens 21 are determined. It is changed to a randomly changed state (hereinafter, also referred to as "variable array state”).
  • a method of arranging the microlens 21 will be referred to as a "reference arrangement method”.
  • Initial arrangement state of the microlens 21 based on an irregular rectangular lattice (FIG. 5)
  • the initial arrangement state that serves as the reference for the arrangement of the microlens 21 is set.
  • a plurality of microlenses 21 are somewhat regular (quasi-regular) on the XY plane of the reference plane with reference to a rectangular grid having irregularities. ).
  • the rectangular grid according to the present embodiment may be a rectangular grid or a square grid.
  • the rectangular grid includes a plurality of grid lines 32 extending in the first direction (X direction) and a plurality of grid lines 31 extending in the second direction (Y direction).
  • the first direction (X direction) and the second direction (Y direction) are orthogonal to each other.
  • the grid spacing Wx in the X direction is the spacing between a plurality of grid lines 31 extending in the second direction (Y direction).
  • the grid spacing Wy in the Y direction is the spacing between the plurality of grid lines 32 extending in the first direction (X direction).
  • the grid spacing Wx in the X direction fluctuates randomly and differs from each other, and the grid spacing Wy in the Y direction fluctuates randomly. It is a rectangular grid that is different from each other.
  • the three grid spacings Wx 1 , Wx 2 , and Wx 3 in the X direction are different from each other, and the three grid spacings Wy 1 , Wy 2 , and Wy 3 in the Y direction are also different from each other.
  • the grid spacing Wx and the grid spacing Wy may fluctuate independently and randomly without any correlation with each other.
  • the grid spacings Wx 1 , Wx 2 , Wx 3 , Wy 1 , Wy 2 , and Wy 3 in the X and Y directions may be different from each other.
  • the volatility ⁇ Wx and ⁇ Wy are preferably in the range of ⁇ 10% to ⁇ 50%.
  • the volatility ⁇ Wx and ⁇ Wy are set to less than ⁇ 10%, the fluctuations of the lattice spacing Wx and Wy become insufficient, and it becomes difficult to impart sufficient aperiodicity to the microlens array 20. The homogeneity of diffused light may decrease.
  • the volatility ⁇ Wx and ⁇ Wy are set to more than ⁇ 50%, the fluctuation of the lattice spacing W becomes excessively large, and it may be difficult to continuously arrange a plurality of microlenses 21 on the XY plane without gaps. There is.
  • the grid spacing Wx and Wy are within the range of “ ⁇ 10%” or less based on the reference grid spacing Wx_k and Wy_k (that is, Wx_k and Wy_k). 90% or more and 110% or less), and the values are set to randomly deviate from the reference grid spacings Wx_k and Wy_k.
  • the plurality of lattice spacings Wx 1 , Wx 2 , Wx 3 , ..., Wy 1 , Wy 2 , Wy 3 , ... In the X and Y directions are different from each other. Randomly set the value. Then, using the grid spacing Wx 1 , Wx 2 , Wx 3 , ..., Wy 1 , Wy 2 , Wy 3 , ..., Irregular rectangular grids with different grid spacing Wx, Wy (Fig.) 5) is set.
  • This state is the initial arrangement state that serves as a reference for the arrangement of the microlens 21.
  • the planar shape of each microlens 21 is a rectangular shape corresponding to a rectangular grid, and the outline of the planar shape of the microlens 21 coincides with the grid lines 31 and 32 in the X and Y directions. .. Further, the position of the apex 22 of each microlens 21 coincides with the center point 23 of each rectangular grid surrounded by the grid lines 31 and 32.
  • the aperture diameters Dx and Dy of each microlens 21 in the X direction and the Y direction correspond to the lattice spacings Wx and Wy in the X direction and the Y direction, respectively.
  • the aperture diameters Dx and Dy also fluctuate to different values.
  • each microlens 21 in the initial arrangement state is a shape obtained by cutting out a predetermined reference shape (for example, a reference shape having an aspherical shape) set in advance by a rectangular lattice corresponding to each microlens 21. ing.
  • a predetermined reference shape for example, a reference shape having an aspherical shape
  • the aperture diameters Dx and Dy and the surface shape of the plurality of microlenses 21 are different from each other.
  • the plurality of microlenses 21 by arranging the plurality of microlenses 21 with reference to the irregular rectangular lattice, in the initial arrangement state, the plurality of microlenses so that the aperture diameters Dx, Dy and the surface shape of the microlenses 21 are different from each other. 21 can be arranged.
  • FIG. 6 First variable arrangement state of the microlens 21 in which the radius of curvature Rx and Ry are varied.
  • FIG. 6 shows an example in which the radius of curvature Rx and Ry of the aspherical shape are changed when the surface shape of the microlens 21 is an aspherical shape having anisotropy in the X direction.
  • the radius of curvature R includes the radius of curvature Rx of the cross-sectional shape of the microlens 21 cut in the cross section in the X direction and the radius of curvature Ry of the cross-sectional shape of the microlens 21 cut in the cross section in the Y direction.
  • Rx and Ry have the same value.
  • Rx and Ry can have different values.
  • the method of randomly changing the radii of curvature Rx and Ry of the microlens 21 in the initial arrangement state is as follows, for example.
  • constant reference values Rx_k and Ry_k (hereinafter referred to as reference curvature radii Rx_k and Ry_k) that serve as a reference for fluctuations in the radius of curvature Rx and Ry in the X and Y directions are set.
  • the volatility ⁇ Rx and ⁇ Ry are preferably in the range of ⁇ 10% to ⁇ 50%.
  • the volatility ⁇ Rx and ⁇ Ry are set to less than ⁇ 10%, the fluctuations of the radius of curvature Rx and Ry become insufficient, and it becomes difficult to impart sufficient aperiodicity to the microlens array 20. The homogeneity of diffused light may decrease.
  • the volatility ⁇ Rx and ⁇ Ry are set to more than ⁇ 50%, the fluctuations of the radius of curvature Rx and Ry become excessively large, and it becomes difficult to continuously arrange a plurality of microlenses 21 on the XY plane without gaps. There is a risk of becoming.
  • the radius of curvature Rx and Ry of each microlens 21 in the initial arrangement state are randomly changed (first variation arrangement state).
  • the radius of curvature Rx of the microlenses 21 arranged in the X direction in the X direction has different values from each other.
  • the radius of curvature Ry of the microlenses 21 arranged in the Y direction in the Y direction have different values.
  • the radius of curvature Rx randomly fluctuates with a volatility ⁇ Rx within ⁇ 10% to ⁇ 50% with reference to the reference radius of curvature Rx_k.
  • the radius of curvature Ry randomly fluctuates at a volatility ⁇ Ry within ⁇ 10% to ⁇ 50% with reference to the reference radius of curvature Ry_k.
  • each microlens 21 In the first variable arrangement state, as shown in FIG. 6, the planar shape of each microlens 21 is deviated from the rectangular lattice, and the outline of the planar shape of the microlens 21 is a lattice in the X direction and the Y direction. It may not match the lines 31 and 32. However, the positions of the vertices 22 of each microlens 21 coincide with the center point 23 of each rectangular grid. Further, in the first variable arrangement state, the aperture diameters Dx and Dy of each microlens 21 in the X direction and the Y direction deviate from the lattice spacing Wx and Wy in the X direction and the Y direction.
  • the aperture diameters Dx and Dy and the surface shape of the microlens 21 are further different from each other than in the initial arrangement state.
  • a plurality of microlenses 21 can be arranged.
  • the second variable arrangement state of the microlens 21 in which the lens apex position is changed (FIG. 7).
  • the plane position of the apex 22 of the microlens 21 is randomly eccentric from the center point 23 of the rectangular lattice.
  • the eccentricity means that the plane position of the apex 22 of the microlens 21 is changed so as to deviate from the center point 23 of the rectangular lattice on the XY plane.
  • the center point 23 of the rectangular grid is an intersection of two diagonal lines of the rectangular grid (see FIG. 4).
  • the method of randomly eccentricizing the plane position of the apex 22 of the microlens 21 in the first variable arrangement state is as follows.
  • the eccentricity Ec of the plane position of the apex 22 of the microlens 21 (hereinafter, may be referred to as the lens apex position 22) is set.
  • the eccentricity Ec is the amount of deviation (distance) of the lens apex position 22 from the center point 23 of the rectangular lattice.
  • the eccentricity Ec is represented by the eccentricity Ecx in the X direction and the eccentricity Ecy in the Y direction.
  • the eccentricity Ecx is the amount of deviation of the lens apex position 22 from the center point 23 of the rectangular lattice in the X direction
  • the eccentricity Ecy is the amount of deviation of the lens apex position 22 from the center point 23 of the rectangular lattice in the Y direction. is there.
  • the eccentricities ⁇ Ecx and ⁇ Ecy in the X and Y directions are set.
  • the eccentricity ⁇ Ecx in the X direction is the ratio (percentage) of the eccentricity Ecx to the lattice spacing Wx of the rectangular lattice.
  • the eccentricity ⁇ Ecy in the Y direction is the ratio (percentage) of the eccentricity Ecy to the lattice spacing Wy of the rectangular lattice.
  • the eccentricity ⁇ Ecx and ⁇ Ecy are expressed by the following equations.
  • ⁇ Ecx [%] Ecx / Wx ⁇ 100
  • ⁇ Ecy [%] Ecy / Wy ⁇ 100
  • the lens apex position is eccentric based on the eccentricity ⁇ Ecx and ⁇ Ecy set above. Specifically, the lens apex position 22 of each microlens 21 is randomly eccentric with eccentricity ratios ⁇ Ecx and ⁇ Ecy within ⁇ 10% to ⁇ 50%.
  • the eccentricity ⁇ Ecx and ⁇ Ecy are preferably in the range of ⁇ 10% to ⁇ 50%.
  • the eccentricity ratios ⁇ Ecx and ⁇ Ecy are set to less than ⁇ 10%, the eccentricity amounts Ecx and Ecy at the lens apex position 22 become insufficient, and it becomes difficult to impart sufficient aperiodicity to the microlens array 20. There is a risk that the homogeneity of the diffused light in the X and Y directions due to the array 20 will decrease.
  • the plane position of the apex 22 of each microlens 21 in the first variable arrangement state is randomly changed from the center point 23 of the rectangular lattice (second variable arrangement state).
  • the plane positions of the vertices 22 of each microlens 21 are shifted in random directions on the XY plane by random eccentricities Ecx and Ecy.
  • each microlens 21 corresponds to a rectangular lattice more than in the first variable arrangement state (see FIG. 6). The shape deviates from the rectangular shape. Further, in the second variable arrangement state, the aperture diameters Dx and Dy of each microlens 21 in the X and Y directions are further deviated from the lattice spacings Wx and Wy in the X and Y directions.
  • the surface shape, opening diameters Dx, and Dy of the microlens 21 are further higher than those in the first variable arrangement state.
  • a plurality of microlenses 21 can be arranged so as to be different from each other.
  • the height positions of the vertices 22 of the plurality of microlenses 21 are mutually variable. Specifically, as shown in FIG. 2, the height positions of the apex 22 (the deepest point of the concave lens) of the plurality of microlenses 21 arranged in the X direction are different from each other, and the plurality of microlenses arranged in the Y direction are arranged. The height positions of the apex 22 (the deepest point of the concave lens) of the microlens 21 are also different from each other. As a result, the randomness of the shapes and arrangements of the plurality of microlenses 21 can be further enhanced, and sufficient aperiodicity can be imparted to the microlens array 20.
  • a plurality of microlenses 21 are quasi-regularly based on an irregular rectangular grid having different grid spacings Wx and Wy. (Initial arrangement state: Fig. 5).
  • the microlenses 21 are arranged semi-regularly in the XY plane so that the outer line of the planar shape of each microlens 21 is along the grid lines 31 and 32 of the irregular rectangular lattice.
  • the radius of curvature Rx, Ry, the surface shape, and the lens apex position 22 of the plurality of arranged microlenses 21 are randomly changed (first and second variable arrangement states: FIGS. 6 and 7).
  • the surface shape (three-dimensional shape), aperture shape (planar shape), aperture diameters Dx, Dy, arrangement, and the like of the semi-regularly arranged microlenses 21 can be randomly dispersed. Therefore, it is possible to realize a three-dimensional surface structure of the microlens array 20 with high randomness while realizing a semi-regular arrangement of the microlens 21.
  • the microlens array 20 it is possible to suitably control the phase superposition state of the light emitted from each microlens 21. Therefore, interference of diffused light from each microlens 21 and diffraction due to the periodic structure of the microlens arrangement can be suitably suppressed. Therefore, the unevenness of the intensity distribution of the diffused light can be reduced, and the homogeneity of the light distribution in the X and Y directions orthogonal to each other can be improved. Further, it is possible to control the anisotropy of the light distribution in the X and Y directions and the cutoff property of the intensity distribution of the diffused light.
  • the cutoff property means that the diffused light from the microlens array 20 has a so-called top hat type diffusion characteristic.
  • the top hat type diffusion characteristic is the homogeneity of the energy distribution within the angular component in a certain region with respect to collimated light in the visible light region and telecentric light having a collimating main ray and a constant aperture. Is very high, and refers to an optical function in which the energy can be rapidly reduced when a certain region of this angular component is exceeded.
  • the luminance distribution of the diffused light of the light incident on the microlens array 20 becomes substantially uniform within a predetermined diffusion angle range, and the diffused light is within a predetermined diffusion angle range. A state in which the brightness value of is within the range of, for example, ⁇ 20% with respect to the average value of the peak level is realized.
  • a plurality of microlenses 21 are arranged in a rectangular grid by the above arrangement method, and the radius of curvature Rx, Ry, lens apex position 22 and the like of each microlens 21 are appropriately set. It is controlled or an aspherical shape is introduced into the surface shape of the microlens 21. As a result, the desired diffusion characteristics of the microlens array 20 can be realized, so that the top hat type diffusion characteristics can be more reliably realized.
  • a plurality of microlenses 21 are arranged semi-regularly on the XY plane with reference to an irregular rectangular lattice having different lattice intervals Wx and Wy (initial arrangement state). ), The radius of curvature Rx, Ry, and the lens apex position 22 are changed (first and second variable arrangement states).
  • a plurality of microlenses 21 can be continuously arranged on the surface of the diffuser plate 1 without gaps while ensuring the randomness of the surface shape of each microlens 21.
  • the flat portion can be prevented from existing at the boundary portion of the adjacent microlens 21 as much as possible, the component (0th-order transmitted light component) of the incident light that is transmitted as it is without being scattered on the surface of the diffuser plate is suppressed. It becomes possible. As a result, the homogeneity of the light distribution in the X and Y directions orthogonal to each other and the diffusion performance can be further improved.
  • a plurality of microlenses 21 having anisotropy in a common direction may be arranged in a rectangular grid pattern over the entire microlens array 20.
  • the anisotropy microlens 21 is, for example, a microlens having a planar shape in which the length in one direction (longitudinal direction) is longer than the length in the other direction (short direction) orthogonal to the one direction.
  • a plurality of anisotropic microlenses 21 are arranged on the XY plane of the base material 10 so that the longitudinal directions of the microlenses 21 face the same direction.
  • the diffusion width of light in the longitudinal direction of the microlens 21 is reduced, and the diffusion width of light in the lateral direction is increased.
  • the anisotropic shape of the light diffused by the diffuser plate 1 can be controlled according to the shape of the projection surface.
  • each microlens 21 has an aspherical shape having anisotropy extending in a predetermined direction.
  • aspherical shape for example, a first aspherical shape example (anamorphic shape) and a second aspherical shape example (torus shape) described below can be used.
  • FIG. 8 is an explanatory view showing a planar shape of the anamorphic-shaped microlens 21.
  • FIG. 9 is a perspective view showing the three-dimensional shape of the anamorphic-shaped microlens 21.
  • FIG. 10 is a perspective view showing a curved surface having an anamorphic shape.
  • the microlens 21 shown in FIGS. 8 and 9 is a so-called anamorphic lens, and its surface shape is an aspherical shape including a curved surface of the anamorphic shape.
  • the planar shape of the microlens 21 is an anisotropy elliptical shape.
  • the major axis of the elliptical shape in the Y-axis direction is Dy
  • the minor axis in the X-axis direction is Dx.
  • the three-dimensional shape of the microlens 21 is an aspherical curved surface having predetermined radius of curvature Rx and Ry in each of the major axis direction and the minor axis direction of the elliptical shape.
  • the microlens 21 has an aspherical shape having anisotropy in the Y-axis direction.
  • FIG. 10 is a perspective view showing an anamorphic curved surface (aspherical surface) represented by the following mathematical formula (1).
  • the following formula (1) is an example of a formula representing a curved surface (aspherical surface) having an anamorphic shape.
  • 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 y6 4th and 6th aspherical coefficients in the Y direction
  • the minor axis of the elliptical shape on the XY plane in the X direction is Dx
  • the major axis in the Y direction is Dy.
  • Cut out a curved surface A part of the curved surface shape cut out is set to the curved surface shape (anamorphic shape) of the microlens 21.
  • the elliptical major axis Dy, 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 fluctuation rate ⁇ for each microlens 21. Randomly fluctuate within the range of to make it vary. Thereby, the surface shapes of a plurality of microlenses 21 having different anamorphic shapes can be set.
  • FIG. 11 is an explanatory view showing a planar shape of the torus-shaped microlens 21.
  • FIG. 12 is a perspective view showing the three-dimensional shape of the torus-shaped microlens 21.
  • FIG. 13 is a perspective view showing a torus-shaped curved surface.
  • the surface shape of the microlens 21 according to the second aspherical shape example is an aspherical shape including a part of the curved surface of the torus shape.
  • a torus is a surface of revolution obtained by rotating a circle. Specifically, as shown in FIG. 13, the small circle (radius: r) is centered on the rotation axis (X-axis) arranged outside the small circle (radius: r) along the circumference of the large circle (radius: R). By rotating the circle, a so-called donut-shaped torus is obtained.
  • the curved surface shape of the surface (torus surface) of this annular body is a torus shape. By cutting out the outer portion of the torus shape, the three-dimensional shape of the torus-shaped microlens 21 as shown in FIG. 12 can be obtained.
  • the planar shape of the torus-shaped microlens 21 is an elliptical shape having anisotropy.
  • 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 diameters Dx and Dy of the microlens 21 in the X and Y directions.
  • the three-dimensional shape of the microlens 21 is an aspherical curved surface having predetermined radius of curvature R and r in each of the major axis direction and the minor axis direction of the elliptical shape.
  • the microlens 21 has an aspherical shape having anisotropy in the Y-axis direction.
  • FIG. 13 is a perspective view showing an aspherical curved surface represented by the following mathematical formula (2).
  • R is the radius of the great circle and r is the radius of the small circle.
  • the curved surface is such that the minor axis of the elliptical shape on the XY plane in the X direction is r and the major axis in the Y direction is R. Cut out. A part of the curved surface shape cut out is set to the curved surface shape (torus shape) of the microlens 21.
  • the radius of curvature Rx) is randomly varied within a predetermined fluctuation rate ⁇ for each microlens 21 to be dispersed. Thereby, the surface shapes of a plurality of microlenses 21 having different torus shapes can be set.
  • the surface shape (aspherical shape having anisotropy) of the microlens 21 according to the present embodiment in addition to the examples of the first and second aspherical shapes, for example, an aspherical surface cut out from an elliptical sphere. Shapes can be used.
  • FIG. 14 is a flowchart showing a method of designing a microlens according to the present embodiment.
  • (S10) Setting of grid parameters As shown in FIG. 14, first, various parameters (grid parameters) relating to a rectangular grid (grid) as a reference for arranging a plurality of microlenses 21 on an XY plane are set (S10). ..
  • the grid parameters include, for example, the following parameters.
  • Wy_k [ ⁇ m] Reference value of grid spacing Wy in the Y direction (grid size in the Y direction)
  • ⁇ Wy [ ⁇ %] Fluctuation rate of grid spacing Wy in the Y direction (allowable fluctuation range of Wy in the Y direction)
  • the setting value of the grid parameter can be set to the following numerical values, for example.
  • Wx_k 120 ⁇ m
  • Wy_k 90 ⁇ m ⁇ Wx: ⁇ 20%
  • ⁇ Wy ⁇ 10%
  • ⁇ Ecx ⁇ 10%
  • ⁇ Ecy ⁇ 10%
  • FIG. 15 is an explanatory diagram showing a rectangular grid generated in this step S12. As shown in FIG. 15, an irregular rectangular grid in which the grid spacing Wx and Wy in the X and Y directions fluctuate randomly is set.
  • the grid spacing Wx in the X direction is the spacing between grid lines 31 adjacent to the X direction.
  • the grid spacing Wy in the Y direction is the spacing between grid lines 32 adjacent to the Y direction.
  • the grid spacing Wx in the X direction is set to a value obtained by randomly varying the reference grid spacing Wx_k [ ⁇ m] at the volatility ⁇ Wx [ ⁇ %].
  • the grid spacing Wy in the Y direction is set to a value obtained by randomly varying the reference grid spacing Wy_k [ ⁇ m] at a volatility ⁇ Wy [ ⁇ %].
  • the grid spacing Wx is 96 ⁇ m to 144 ⁇ m (80% of 120 ⁇ m) centered on 120 ⁇ m (Wx_k). It is set to a random value within the range of 120%).
  • the grid spacing Wy is also set in the same manner. As a result, as shown in FIG. 15, the lattice spacings Wx and Wy of the plurality of rectangular lattices arranged in the X and Y directions are set to different values.
  • FIG. 16 is an explanatory diagram showing a rectangular grid whose grid center is eccentric in this step S14.
  • the grid center before the eccentric processing is arranged at the coordinate position of the intersection of the two diagonal lines of each rectangular grid (the center point 23 of the rectangular grid described above).
  • the center of the grid moves to the X and Y coordinate positions corresponding to the eccentricities Ecx and Ecy randomly calculated using the eccentricity ⁇ Ecx and the eccentricity ⁇ Ecy.
  • the eccentricity Ecx and Ecy are 90% to 110% of the lattice spacing Wx and Wy. Set to a value within the range.
  • the center of the grid is moved in the X and Y directions by a distance corresponding to the eccentricities Ecx and Ecy.
  • the position of the center of the grid after movement corresponds to the plane position (lens apex position 22) of the apex 22 of the microlens 21 described above.
  • the microlenses 21 corresponding to each rectangular grid are arranged based on the rectangular grid generated in S12 and the grid center eccentric in S14. Specifically, first, the basic shape of the surface shape (lens surface) of the microlens 21 is selected (S16). Next, parameters (lens parameters) related to the selected basic shape are set (S18, S20). After that, the shape of the microlens 21 in each rectangular lattice is determined based on the set lens parameters, and the Z coordinate position representing the shape of the microlens 21 is calculated to generate the microlens 21 (S22, S24). ..
  • an anamorphic shape or a torus shape is selected as the basic shape of the microlens 21 (hereinafter referred to as a lens shape) (S16).
  • a lens shape S16
  • the present invention is not limited to this, and other types of aspherical shapes or spherical shapes may be selected as the lens shape.
  • the anamorphic shape lens parameters include, for example, the following parameters.
  • ⁇ Ry [ ⁇ %] Volatility of radius of curvature Ry in the Y direction (allowable fluctuation range of Ry in the Y direction)
  • the set value of the lens parameter of the anamorphic shape can be set to the following numerical values, for example.
  • Rx_k 240 ⁇ m
  • Ry_k 200 ⁇ m
  • Rx ⁇ 10%
  • ⁇ Ry ⁇ 10%
  • the surface shape of the anamorphic microlens 21 is generated based on the lens parameters set in S18 (S22). Specifically, the surface shape of each microlens 21 is determined based on the lens parameters, and each microlens 21 is arranged on each rectangular lattice. That is, the Z coordinate value of each point on the anamorphic lens surface is calculated.
  • FIG. 17 is an explanatory diagram showing a plurality of microlenses 21 generated in this step S22.
  • each microlens 21 is arranged on each rectangular grid so that the lens apex position 22 coincides with the grid center position eccentric in S14. Further, the radius of curvature Rx and Ry of each microlens 21 in the X and Y directions fluctuate randomly. Therefore, a plurality of microlenses 21 having different surface shapes (anamorphic shapes) are arranged so as to overlap each other on the XY plane.
  • the radius of curvature Rx in the X direction is set to a value obtained by randomly varying the reference radius of curvature Rx_k [ ⁇ m] at the volatility ⁇ Rx [ ⁇ %].
  • the radius of curvature Ry in the Y direction is set to a value obtained by randomly varying the reference radius of curvature Ry_k [ ⁇ m] with a volatility ⁇ Ry [ ⁇ %].
  • the radius of curvature Rx is 216 ⁇ m to 264 ⁇ m (90% of 240 ⁇ m) centered on 240 ⁇ m (Rx_k).
  • the radius of curvature Ry is also set in the same manner. As a result, as shown in FIG. 17, the surface shapes (anamorphic shapes) of the plurality of microlenses 21 arranged in the X and Y directions are different from each other.
  • the torus-shaped lens parameters include, for example, the following parameters.
  • the small circle radius r and the great circle radius R are radii of curvature that define the torus shape shown in FIGS. 11 to 13.
  • r_k [ ⁇ m] Reference value of small circle radius (radius of curvature Rx in X direction)
  • R_k [ ⁇ m] Reference value of great circle radius (radius of curvature Ry in Y direction)
  • ⁇ Rx [ ⁇ %] Small circle radius (X direction) Rate of fluctuation of radius of curvature Rx) (allowable fluctuation range of r in the X direction)
  • ⁇ Ry [ ⁇ %] Volatility of great circle radius (radius of curvature Ry in Y direction) (allowable fluctuation range of R in Y direction)
  • the set value of the lens parameter of the torus shape can be set to the following numerical values, for example.
  • Rx_k 240 ⁇ m
  • Ry_k 200 ⁇ m
  • Rx ⁇ 10%
  • ⁇ Ry ⁇ 10%
  • the surface shape of the torus-shaped microlens 21 is generated based on the lens parameters set in S20 (S24). Specifically, the surface shape of each microlens 21 is determined based on the lens parameters, and each microlens 21 is arranged on each rectangular lattice. That is, the Z coordinate value of each point on the torus-shaped lens surface is calculated. Since the torus-shaped lens generation process in step S24 is the same as the anamorphic-shaped lens generation process in S22, detailed description thereof will be omitted.
  • a lens pattern representing the shape and arrangement of the microlens 21 generated in S20 or S24 is output (S26). For example, a file of XYZ coordinate values representing the lens pattern and an image file expressing the Z coordinate values of the lens pattern in shade gradation are output.
  • FIG. 18 is an image showing a lens pattern designed by the design method according to the present embodiment. As shown in FIG. 18, a plurality of microlenses 21 are arranged in an irregular rectangular lattice pattern on the XY plane. The lens apex position 22 of each microlens 21 is randomly eccentric, and the radii of curvature Rx and Ry of each microlens 21 also randomly fluctuate.
  • the plurality of microlenses 21 have different aspherical shapes (for example, anamorphic shape or torus shape). Further, the plurality of microlenses 21 have different planar shapes from each other.
  • the planar shape of each microlens 21 generally has a substantially rectangular shape along the rectangular lattice, but has a shape that varies from one to another.
  • the four side portions are generally composed of straight lines, but the four corner portions are composed of curved lines.
  • the plurality of microlenses 21 are arranged so as to overlap each other without a gap, and there is no flat portion at the boundary portion between the microlenses 21 adjacent to each other.
  • a plurality of microlenses 21 are arranged semi-regularly with reference to the above-mentioned irregular rectangular lattice, and each of the microlenses 21 is arranged.
  • the variable elements (lattice spacing Wx, Wy, radius of curvature Rx, Ry, lens apex position 22, etc.) are randomly changed.
  • the microlens array 20 having such a configuration has a variety of highly homogeneous light distribution controllability, with small macro light amount fluctuations depending on the lens surface structure and light amount changes due to diffracted light.
  • FIG. 19 is a flowchart showing a manufacturing method of the diffusion plate 1 according to the present embodiment.
  • the base material (the base material of the master master or the base material 10 of the diffusion plate 1) is washed (step S101).
  • the base material may be, for example, a roll-shaped base material such as a glass roll, or a flat plate-shaped base material such as a glass wafer or a silicon wafer.
  • a resist is formed on the surface of the base material after cleaning (step S103).
  • a resist layer can be formed by a resist using a metal oxide.
  • a resist layer can be formed on a roll-shaped substrate by spray-coating or dipping the resist.
  • a resist layer can be formed on a flat substrate by applying various coating treatments to the resist.
  • a positive type photoreactive resist may be used, or a negative type photoreactive resist may be used.
  • a coupling agent may be used in order to improve the adhesion between the base material and the resist.
  • the resist layer is exposed using a pattern corresponding to the shape of the microlens array 20 (step S105).
  • Such an exposure process is a known exposure method such as exposure using a gray scale mask, multiple exposure by superimposing a plurality of gray scale masks, or laser exposure using a picosecond pulse laser, a femtosecond pulse laser, or the like. May be applied as appropriate.
  • the exposed resist layer is developed (S107).
  • a developing process By such a developing process, a pattern is formed on the resist layer.
  • the developing process can be executed by using an appropriate developer depending on the material of the resist layer.
  • the resist layer when the resist layer is formed of a resist using a metal oxide, the resist layer can be alkaline-developed by using an inorganic or organic alkaline solution.
  • a master master with the shape of the microlens array 20 formed on the surface is completed (S111).
  • a glass master can be manufactured by glass-etching a glass base material using a resist layer on which a pattern is formed as a mask.
  • a metal master can be manufactured by performing Ni sputtering or nickel plating (NED treatment) on the resist layer on which the pattern is formed to form a nickel layer on which the pattern is transferred, and then peeling off the base material. ..
  • a metal master master is manufactured by forming a nickel layer to which a resist pattern is transferred by Ni sputtering having a film thickness of about 50 nm or nickel plating having a film thickness of 100 ⁇ m to 200 ⁇ m (for example, a Ni bath with sulfamic acid). can do.
  • the master master for example, glass master master, metal master master
  • S111 an inverted shape of the microlens array 20 is formed on the surface.
  • the soft mold is created (S113).
  • the pattern of the microlens array 20 is transferred to a glass substrate, a film substrate, or the like (S115), and a protective film, an antireflection film, or the like is further formed as necessary. (S117), the diffuser plate 1 according to the present embodiment is manufactured.
  • a soft mold is manufactured (S113) using the master master (S111) and then the diffusion plate 1 is manufactured (S115) by transfer using the soft mold
  • a master master for example, an inorganic glass master
  • the diffusion plate 1 may be manufactured by imprinting using the master master.
  • an acrylic photo-curing resin is applied to a base material made of PET (PolyEthylene Terephthalate) or PC (PolyCarbonate), the pattern of the master master is transferred to the applied acrylic photo-curing resin, and the acrylic photo-curing resin is UV. By curing, the diffuser plate 1 can be manufactured.
  • the diffusion plate 1 when the diffusion plate 1 is manufactured by directly processing the glass base material itself, the base material 10 is dried using a known compound such as CF 4 following the development treatment in step S107.
  • the diffusion plate 1 according to the present embodiment is manufactured by performing an etching process (S119) and then forming a protective film, an antireflection film, or the like as needed (S121).
  • the manufacturing method shown in FIG. 19 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 a device that needs to diffuse light in order to realize its function.
  • a device that needs to diffuse light in order to realize its function.
  • Examples of such a device include display devices such as various displays (for example, LEDs 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 diffuser plate integrated lens, and the like, and can also be applied to an application of optical shaping.
  • the diffuser plate 1 can also be applied to a transmission screen, a Fresnel lens, a reflection screen, and the like of a projection device.
  • the diffuser plate 1 can be applied to various lighting devices used for spot lighting, base lighting and the like, various special lightings, various screens such as an intermediate screen and a final screen, and the like.
  • the diffuser plate 1 can also be applied to applications such as diffusion control of light source light in an optical device, such as light distribution control of an LED light source device, light distribution control of a laser light source device, 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 example, and can be applied to any known device as long as it is a device that utilizes light diffusion.
  • the diffuser plates according to Examples and Comparative Examples were manufactured by the manufacturing method described below.
  • a photoreactive resist was applied to one surface (main surface) of the glass base material with a resist thickness of 2 ⁇ m to 15 ⁇ 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 Co., Ltd.) was used.
  • a pattern was drawn on the resist on the glass substrate with a laser drawing apparatus using a laser having a wavelength of 405 nm, and the resist layer was exposed.
  • the resist layer may be exposed by performing mask exposure on the resist on the glass substrate with a stepper exposure apparatus using g-rays.
  • a pattern was formed on 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 diffuser plate was manufactured by etching the glass substrate with the resist on which the pattern was formed. Specifically, a diffusion plate was manufactured by forming a resist pattern on a glass substrate by glass etching using Ar gas or CF 4 gas.
  • Table 1 shows the design conditions of the surface structure of the microlens array and the evaluation result of the homogeneity of the light distribution by the diffuser plate with respect to the diffuser plates according to the examples and comparative examples manufactured as described above.
  • the microlens array was designed by the design method shown in FIGS. 14 to 18 described above.
  • various parameters such as grid parameters (Wx_k, Wy_k, ⁇ Wx, ⁇ Wy, ⁇ Ecx, ⁇ Ecy) and lens parameters (Rx_k, Ry_k, ⁇ Rx, ⁇ Ry) shown in Table 1 are appropriately changed to surface different microlenses.
  • a shape pattern was generated.
  • a lens pattern representing the shape and arrangement of the microlenses according to each Example and Comparative Example was output. Using this lens pattern, the diffuser plates according to each Example and Comparative Example were manufactured by the above manufacturing method.
  • the radius of curvature Rx and the radius of curvature Ry were set to fixed values or randomly fluctuating values for each Example and Comparative Example.
  • the surface shape of the microlens was a spherical shape in Examples 1 to 4, 8 and 9 and Comparative Examples 1 to 3, and an aspherical shape (for example, an anamorphic shape) in Examples 5 to 7.
  • the planar shape of the microlens array was square in Examples 1 to 7 and Comparative Examples 1 to 3, and rectangular (long in the X direction) in Examples 8 and 9 and Comparative Example 4.
  • the surface shape of the microlens array of the diffuser according to Examples 1 to 9 and Comparative Examples 1 to 4 manufactured as described above was observed with a laser microscope. Further, the light distribution pattern of each diffuser is simulated by Virtual-Lab (manufactured by LightTrans), and the light distribution characteristics of each diffuser are measured by the light distribution characteristic measuring instrument Mini-Diff (manufactured by Light Tech). Was measured. Further, in order to measure the light distribution characteristics of the diffuser plate, the intensity distribution of the diffused light was measured from the captured image of the laser light intensity (farfield pattern measurement described later).
  • Simulation results and actual measurement results such as the surface shape pattern of the microlens array of the diffuser plate according to Examples 1 to 9 and Comparative Examples 1 to 4, the light distribution characteristics of the diffused light, the brightness distribution, etc. are shown in FIGS. 20 to 33, respectively. Shown.
  • (a) is an image (BMP) showing a pattern of the surface shape of the microlens array or a confocal laser scanning microscope image (magnification 50 times).
  • B is an image showing the simulation result of light distribution by electromagnetic field analysis.
  • C is a graph (horizontal axis: coordinate position, vertical axis: brightness) showing a simulation result of the brightness distribution of diffused light.
  • (e) is a graph showing the actual measurement result of measuring the far field pattern (FFP) of the diffused light of the laser light source using the actually manufactured diffuser plate (horizontal).
  • Axis Diffuse angle
  • Vertical axis Brightness
  • (F) indicates the diffusion angle (full width at half maximum (FWHM)) in the X and Y directions in the FFP of the (e).
  • (G) is an FFP image showing the actual measurement result of (e).
  • (e) is a graph showing the simulation results of the light distribution characteristics of the diffused light in the X and Y directions (horizontal axis: diffusion angle, vertical axis: vertical axis: Luminance) and (f) indicate the diffusion angles (half-value full width (FWHM)) in the X and Y directions in the luminance distribution of (c) above.
  • the light distribution characteristics (light distribution homogeneity, etc.) of the diffuser plates according to Examples 1 to 9 and Comparative Examples 1 to 3 as described above are evaluated in three stages (evaluation A, B, C) according to the following evaluation criteria. Evaluated in.
  • the evaluation results are shown in Table 1.
  • Evaluation A The homogeneity of the diffused light in the X and Y directions was sufficiently high, and uneven brightness distribution along the rectangular grid was not observed.
  • the brightness distribution of the diffused light is substantially uniform in a predetermined diffusion angle range, and the brightness value of the diffused light is within ⁇ 20% of the average value of the peak levels within the predetermined diffusion angle range. It was.
  • Evaluation B The homogeneity of the diffused light in the X and Y directions was high, and there was some unevenness in the luminance distribution along the rectangular grid, but no large unevenness was observed.
  • the brightness distribution of the diffused light is substantially uniform in a predetermined diffusion angle range, and the brightness value of the diffused light is within ⁇ 40% of the average value of the peak levels within the predetermined diffusion angle range. It was.
  • Evaluation C The homogeneity of the diffused light in the X and Y directions was insufficient, and a large unevenness of the luminance distribution was observed along the rectangular grid.
  • the brightness distribution of the diffused light varied within a predetermined diffusion angle range, and the brightness value of the diffused light did not fall within the range of ⁇ 40% centered on the average value of the peak level within the predetermined diffusion angle range.
  • the homogeneity of the luminance distribution can be improved to some extent by eccentricizing the lens apex position as in Comparative Example 2 or randomly varying the curvature radii Rx and Ry as in Comparative Example 3. it can.
  • the lattice spacings Wx and Wy are constant as in Comparative Examples 1 to 4, the brightness unevenness due to diffraction due to the periodicity of the lattice spacing is homogeneous due to fluctuations in the lens apex position and the radius of curvature Rx and Ry. It is considered that the homogeneity of the light distribution was hindered because the effect of improving the light distribution was exceeded.
  • the microlenses are arranged on the XY plane with reference to the rectangular grid.
  • the rectangular lattices of Examples 1 to 9 are not regular rectangular lattices as in the comparative example, but quasi-regular rectangular lattices having irregularity of lattice intervals Wx and Wy. That is, as shown in FIG. 15, the lattice spacings Wx and Wy of the rectangular lattices of Examples 1 to 9 randomly fluctuate so as to have different values from each other, and the volatility ⁇ Wx and ⁇ Wy are ⁇ 10. % Or more.
  • the aperture diameters Dx, Dy and the planar shape of the microlenses are randomly scattered, and the position of the boundary line between adjacent microlenses is also located. It can be shifted randomly.
  • the outer line of the planar shape of the microlens (the boundary line between the microlenses) is a combination of a curve having an arbitrary radius of curvature and a straight line. It will be composed. As a result, the regularity of arrangement at the boundary between the microlenses is further broken, and the diffraction component can be further reduced. Therefore, it is possible to suppress the diffusion of diffused light between the plurality of microlenses and improve the homogeneity of the diffused light distribution of the entire microlens array.
  • Example 1 Comparison between Example 1 and Examples 2 to 9 (effect of fluctuation of radius of curvature and eccentricity of lens apex) As shown in Table 1, in Example 1, only the lattice spacing Wx and Wy are changed. On the other hand, in Examples 2 to 9, in addition to the lattice spacing Wx and Wy, the radius of curvature Rx and Ry are changed and the lens apex position is eccentric.
  • Examples 2 to 9 were able to suppress unevenness of the luminance distribution more effectively than Example 1 (Evaluation B), and were able to improve the homogeneity of the light distribution of diffused light. From this, it can be seen that from the viewpoint of improving the homogeneity of the light distribution, it is effective to change the radius of curvature Rx and Ry and to eccentric the lens apex position in addition to the lattice spacing Wx and Wy.
  • Examples 2, 3 and 5 the radius of curvature Rx and Ry are changed or the lens apex position is eccentric.
  • the radius of curvature Rx and Ry are varied, and the lens apex position is also eccentric.
  • FIGS. 24 to 29, 32, and 33 As a result, as shown in (b) electromagnetic field analysis image and (c) luminance distribution graph of FIGS. 24 to 29, 32, and 33, in Examples 4, 6 to 9, unevenness of the luminance distribution is further suppressed. It was possible to further improve the homogeneity of the diffused light distribution.
  • Examples 1 to 4 and Examples 5 to 7 Effect of aspherical lens shape
  • a spherical lens was used in Examples 1 to 4 as the basic shape of the microlens.
  • aspherical lenses for example, anamorphic-shaped lenses shown in FIGS. 8 to 10.
  • non-spherical lenses of Examples 5-7 by correcting the aspherical coefficients A 4 of 4 order term of the right side of equation (1) which defines the curved surface of the anamorphic shape described above, defining the lens shape.
  • the aspherical lenses of Examples 5 to 7 are more than the spherical lenses of Examples 1 to 4.
  • the unevenness of the brightness distribution could be suppressed, and a finer light distribution homogeneity could be realized. From this, it can be seen that it is more effective to use an aspherical lens than a spherical lens from the viewpoint of improving the homogeneity of the light distribution.
  • an aspherical lens having anisotropy is used, the anisotropy of the diffused light projected from the diffuser plate can be controlled. Therefore, it is possible to control the light distribution angle to have anisotropy between the X direction and the Y direction while achieving high homogeneity of the diffused light.
  • the surface shape of the microlens of Example 7 satisfies the following relational expressions (A) and (B) in terms of the ratio of the reference radius of curvature Rx_k, Ry_k [ ⁇ m] and the reference lattice spacing Wx_k, Wy_k [ ⁇ m]. It has an aspherical shape.
  • the surface shape of the microlens according to the seventh embodiment is an aspherical shape having the above-mentioned anisotropy, and the lattice spacing Wx, Wy, radius of curvature Rx, and Ry are changed under the conditions shown in Table 1, and the lens.
  • the apex positions are eccentric, and the reference radius of curvature Rx_k, Ry_k [ ⁇ m] and the reference lattice spacing Wx_k, Wy_k [ ⁇ m] are adjusted so as to satisfy the above relational expressions (A) and (B).
  • the diffusion angle (full width at half maximum (FWHM)) of the diffused light emitted from the diffuser plate is within the range of 20 ° or less. This makes it possible to more reliably realize the so-called top hat type diffusion characteristics.
  • the diffusion characteristic of Example 7 realizes the top hat type diffusion characteristic. That is, the brightness distribution of the diffused light of the light incident on the microlens array becomes substantially uniform within a predetermined diffusion angle range (a range of 20 ° or less in the full width at half maximum. In the example of FIG. 10, ⁇ 5 to + 5 °). Within the diffusion angle range, a state in which the brightness value of the diffused light is within ⁇ 20% of the average value of the peak level is realized.
  • Microlens array 21 Microlens 22 Microlens apex 23 Center point of rectangular lattice Wx, Wy lattice spacing Rx, Ry radius of curvature Ecx, Ecy Eccentricity Wx_k, Wy_k Reference lattice spacing Rx_k, Ry_k Reference radius of curvature ⁇ Wx, ⁇ Wy Fluctuation rate ⁇ Rx, ⁇ Ry Fluctuation rate ⁇ Ecx, ⁇ Ecy Eccentricity R Great circle radius r Small circle radius

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  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Optical Elements Other Than Lenses (AREA)

Abstract

La présente invention vise à supprimer une irrégularité de distribution de luminance dans deux directions de microlentilles agencées selon un réseau de grille rectangulaire et à améliorer l'homogénéité dans la distribution de lumière. À cet effet, l'invention concerne une plaque de diffusion de type réseau de microlentilles qui est munie d'un substrat et d'un réseau de microlentilles comprenant une pluralité de microlentilles qui sont agencées en réseau en conformité avec une grille rectangulaire sur un plan X-Y d'au moins une surface du substrat, où : des intervalles Wx de grille dans la direction X des microlentilles agencées en réseau dans la direction X de la grille rectangulaire sont mutuellement différents les uns par rapport aux autres ; des intervalles Wy de grille dans la direction Y des microlentilles agencées en réseau dans la direction Y de la grille rectangulaire sont mutuellement différents les uns par rapport aux autres ; et les microlentilles respectives présentent des formes de surface qui sont différentes les unes par rapport aux autres.
PCT/JP2020/039657 2019-10-25 2020-10-22 Plaque de diffusion, dispositif d'affichage, dispositif de projection et dispositif d'éclairage WO2021079923A1 (fr)

Priority Applications (3)

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EP20878757.2A EP4027177A4 (fr) 2019-10-25 2020-10-22 Plaque de diffusion, dispositif d'affichage, dispositif de projection et dispositif d'éclairage
US17/766,950 US20240077658A1 (en) 2019-10-25 2020-10-22 Diffuser plate, display device, projecting device, and lighting device
CN202080072883.0A CN114556168A (zh) 2019-10-25 2020-10-22 扩散板、显示装置、投影装置以及照明装置

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JP2020175853A JP2021071721A (ja) 2019-10-25 2020-10-20 拡散板、表示装置、投影装置及び照明装置

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
WO2015182619A1 (fr) 2014-05-27 2015-12-03 ナルックス株式会社 Réseau de microlentilles et optique contenant un réseau de microlentilles
WO2016051785A1 (fr) 2014-09-30 2016-04-07 株式会社クラレ Plaque de diffusion, et procédé de conception d'une plaque de diffusion
WO2017043063A1 (fr) * 2015-09-10 2017-03-16 パナソニックＩｐマネジメント株式会社 Plaque de diffusion, et dispositif d'imagerie muni de cette plaque
JP2017068216A (ja) * 2015-10-02 2017-04-06 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
WO2018061816A1 (fr) * 2016-09-28 2018-04-05 パナソニックＩｐマネジメント株式会社 Dispositif d'imagerie
WO2018151097A1 (fr) * 2017-02-15 2018-08-23 ナルックス株式会社 Élément de diffusion

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
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
WO2015182619A1 (fr) 2014-05-27 2015-12-03 ナルックス株式会社 Réseau de microlentilles et optique contenant un réseau de microlentilles
WO2016051785A1 (fr) 2014-09-30 2016-04-07 株式会社クラレ Plaque de diffusion, et procédé de conception d'une plaque de diffusion
WO2017043063A1 (fr) * 2015-09-10 2017-03-16 パナソニックＩｐマネジメント株式会社 Plaque de diffusion, et dispositif d'imagerie muni de cette plaque
JP2017068216A (ja) * 2015-10-02 2017-04-06 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
WO2018061816A1 (fr) * 2016-09-28 2018-04-05 パナソニックＩｐマネジメント株式会社 Dispositif d'imagerie
WO2018151097A1 (fr) * 2017-02-15 2018-08-23 ナルックス株式会社 Élément de diffusion

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