WO2019131933A1 - Optical element, and method for producing optical element - Google Patents

Optical element, and method for producing optical element Download PDF

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Publication number
WO2019131933A1
WO2019131933A1 PCT/JP2018/048301 JP2018048301W WO2019131933A1 WO 2019131933 A1 WO2019131933 A1 WO 2019131933A1 JP 2018048301 W JP2018048301 W JP 2018048301W WO 2019131933 A1 WO2019131933 A1 WO 2019131933A1
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WIPO (PCT)
Prior art keywords
layer
electrode layer
polymer material
material layer
optical element
Prior art date
Application number
PCT/JP2018/048301
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French (fr)
Japanese (ja)
Inventor
山田　泰美
利博 平井
Original Assignee
日東電工株式会社
国立大学法人信州大学
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.)
Filing date
Publication date
Priority claimed from JP2018243599A external-priority patent/JP7246068B2/en
Application filed by 日東電工株式会社, 国立大学法人信州大学 filed Critical 日東電工株式会社
Priority to CN201880081666.0A priority Critical patent/CN111492297A/en
Priority to EP18895859.9A priority patent/EP3734348A4/en
Priority to US16/957,910 priority patent/US20210055544A1/en
Priority to KR1020207017637A priority patent/KR20200100649A/en
Publication of WO2019131933A1 publication Critical patent/WO2019131933A1/en

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    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
    • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
    • 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
    • G02B3/12—Fluid-filled or evacuated lenses
    • G02B3/14—Fluid-filled or evacuated lenses of variable focal length
    • 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
    • G03B15/00—Special procedures for taking photographs; Apparatus therefor

Definitions

  • the present invention relates to an optical element and a method of manufacturing the optical element.
  • a focusing mechanism see, for example, Patent Document 1
  • a lens driving mechanism see, for example, Patent Document 2
  • a polymer material is used for a lens holder for holding a lens, and the position of the lens is moved along the optical axis by using expansion and contraction of the polymer material by applying a voltage.
  • an organic material can be obtained by sandwiching an organic material that expands and contracts in the application direction of the electric field with a pair of electrodes, and providing an electrostrictive strain amount per unit electric field in a plane perpendicular to the application direction of the organic material layer.
  • a method of forming a convex lens, a concave lens and the like by deforming a layer and an electrode has been proposed (see, for example, Patent Document 3).
  • a gel material containing 1 to 30 parts by weight of an ionic liquid to 1 to 50 parts by weight of polyvinyl chloride is known (see, for example, Patent Document 4).
  • the configuration in which the lens is moved along the optical axis changes the position of a single lens by expanding and contracting the polymer material disposed in the lens holder.
  • the holder is first deformed, and the lens position is changed by the deformation of the holder, so it is difficult to sufficiently improve the responsiveness and accuracy of the lens drive.
  • the present invention has an object to provide an optical element capable of adjusting optical characteristics with a simple configuration and a method of manufacturing the same.
  • the present invention provides an optical element capable of controlling light collection and diffusion by using expansion and contraction or deformation of a polymer material by voltage application.
  • the optical element A first electrode layer, A second electrode layer, A polymer material layer disposed between the first electrode layer and the second electrode layer; An insulating spacer layer disposed between the polymer material layer and the second electrode layer to form a predetermined space between the polymer material layer and the second electrode layer; The polymer material layer deforms under voltage application to form one or more light scatterers in the predetermined space.
  • a method of manufacturing an optical element is Forming a polymer material layer on the first electrode layer; An insulating spacer layer and a second electrode layer are disposed on the polymer material layer to form a predetermined space between the polymer material layer and the second electrode layer, A voltage is applied between the first electrode layer and the second electrode layer to deform the polymer material layer to form one or more light scatterers in the space. Including the steps.
  • FIG. 4 is a cross-sectional view taken along line X-X ′ of FIG. 3; It is a manufacturing-process figure of the optical element which has several light-scattering bodies. It is a manufacturing-process figure of the optical element which has several light-scattering bodies. It is a manufacturing-process figure of the optical element which has several light-scattering bodies. It is a manufacturing-process figure of the optical element which has several light-scattering bodies. It is a 3D image which shows the deformation process of the optical element of embodiment.
  • FIG. 6 It is a figure which shows the cross-sectional profile of the optical element (micro lens array) of FIG. 6 as a function of voltage. It is a figure which shows the modification of an optical element, and operation
  • FIG. 1 shows a basic configuration of an optical element 10A as one configuration example of the optical element 10 according to the embodiment.
  • the optical element 10A includes a first electrode layer 12, a second electrode layer 14A, a polymer material layer 11 disposed between the first electrode layer 12 and the second electrode layer 14A, and a polymer material.
  • a spacer layer 13A is disposed between the layer 11 and the second electrode layer 14A.
  • the spacer layer 13A has an opening 16 of a predetermined pattern, and a space 17 is formed between the polymer material layer 11 and the second electrode layer 14A at the position of the opening 16.
  • the polymeric material layer 11 elastically deforms under voltage application to form the light scatterer 15 in the space 17.
  • the light scatterer 15 has a convex shape as described later.
  • the spacer layer 13A may be of any material as long as it is electrically insulating. It may be either an inorganic insulating film or an organic insulating film. In the example of FIG. 1, the spacer layer 13A is an insulating resin film having a predetermined pattern of the openings 16. The planar shape and dimensions of the opening 16 are appropriately designed according to the volume of the space 17 and the shape of the light scatterer 15 generated in the space 17, and are, for example, a circle, an ellipse, a polygon or the like.
  • the diameter of the opening 16 of the spacer layer 13A is set to, for example, less than 1 mm, preferably 300 ⁇ m or less.
  • the diameter of the opening 16 is 1 mm or more, it becomes difficult to project the polymer material layer 11 into the opening 16 by application of a voltage.
  • the diameter of the opening 16 is 300 ⁇ m or less, the deformation efficiency of the polymer material layer 11 with respect to voltage application is improved, and a convex shape can be formed.
  • the polymer material layer 11 and the light scattering body 15 are formed of a gel-like polymer material (hereinafter, appropriately referred to as “polymer gel”).
  • the light scatterer 15 is formed by using expansion and contraction or deformation of the polymer gel by application of a voltage.
  • the polymer gel is polyvinyl chloride (PVC), polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber, etc., and is transparent to the used wavelength.
  • Polymer (or resin) material can be selected appropriately.
  • PVC which is easily modified due to the action of the electric field
  • a suitable plasticizer may be added to PVC, or PVC may be dissolved in a solvent.
  • a plasticizer dibutyl adipate (DBA: dibutyl adipate), diethyl adipate (DEA: diethyl adipate), diethyl sebacate (DES: diethyl sebacate), dioctyl phthalate (DOP: dioctyl phthalate), diethyl phthalate (DEP: diethyl phthalate) etc.
  • DBA dibutyl adipate
  • DEA diethyl adipate
  • DES diethyl sebacate
  • DOP dioctyl phthalate
  • DEP diethyl phthalate
  • Tetrahydrofuran (THF) etc. can be used as a solvent.
  • the mixing ratio of the plasticizer is 50 wt% or more, preferably 75 wt% or more. If the mixing ratio is less than 50 wt%, it becomes difficult to deform the polymer material layer 11 even if a voltage is applied. When the mixing ratio is 50 wt% or more and less than 75 wt%, the polymer material layer 11 can be deformed by voltage application, but the voltage level to be applied may be high. By setting the mixing ratio to 75 wt% or more, the polymer material layer 11 can be deformed at an appropriate voltage level.
  • the first electrode layer 12 is not particularly limited as long as it is a conductive material.
  • the first electrode layer 12 is formed of a metal, platinum, gold, silver, nickel, chromium, copper, titanium, tantalum, indium, palladium, lithium, niobium, an alloy of these, or the like can be used.
  • the first electrode layer 12 may be formed of a transparent oxide semiconductor material such as ITO (Indium Tin Oxide: indium tin oxide), or a conductive polymer, conductive carbon, or the like may be used.
  • the second electrode layer 14A is preferably a transparent electrode layer. By using the second electrode layer 14A as a transparent electrode layer, light collected or diffused by the light scatterer 15 can be transmitted.
  • the polarities of the first electrode layer 12 and the second electrode layer 14A can be set according to the direction in which the shape of the polymer material layer 11 is changed.
  • the polymer material layer 11 is made of a material that is easily negatively charged
  • the first electrode layer 12 is a cathode
  • the second electrode layer 14A is an anode.
  • a part of the surface on the anode side of the polymer material layer 11 is in surface contact with the spacer layer 13A.
  • the polymer material layer 11 is deformed in a region not in surface contact with the spacer layer 13A (ie, a region exposed in the opening 16) by application of a voltage, and is pulled toward the second electrode layer 14A.
  • the optical element 10A can be manufactured, for example, by the following procedure.
  • a solution of PVC to which a plasticizer is added is applied by a cast method or the like to form a polymer material layer 11.
  • the spacer layer 13A in which the pattern of the openings 16 is formed in advance and the second electrode layer 14A are disposed.
  • the arrangement of the spacer layer 13A and the arrangement of the second electrode layer 14A may be simultaneous or sequentially.
  • a predetermined voltage is applied between the first electrode layer 12 and the second electrode layer 14 A to form the light scatterer 15 in the space 17 formed by the opening 16.
  • the thickness of the polymer material layer 11 is appropriately determined in accordance with the diameter and depth of the opening 16, the height of the light scatterer 15 to be formed, the thickness of the first electrode layer 12 and the thickness of the second electrode layer 14A, etc. Be done.
  • the thickness of the polymer material layer 11 is 1 mm or less, preferably 0.1 mm to 0.5 mm.
  • the thickness of the polymer material layer 11 may be 0.1 mm or less.
  • the thickness of the spacer layer 13A is 1 mm or less, preferably 0.1 mm or less.
  • FIG. 2 is a diagram for explaining the operation principle of the optical element 10A of the embodiment.
  • (A) of FIG. 2 shows the state to which the voltage is not applied.
  • (B) of FIG. 2 shows the state when a voltage is applied.
  • the polymer material layer 11 is positioned between the first electrode layer 12 and the second electrode layer 14A in a state where the surface is flat. Since the spacer layer 13A is provided between the polymer material layer 11 and the second electrode layer 14A, a part of the polymer material layer 11 is in surface contact with the spacer layer 13A. At the position of the opening 16 formed in the spacer layer 13A, a space 17 is formed between the polymer material layer 11 and the second electrode layer 14A.
  • a gel polymer material layer is formed from the first electrode layer 12 which is a cathode. Electrons are injected into 11. The polymer gel containing electrons is pulled toward the surface of the second electrode layer 14A which is an anode.
  • the spacer layer 13A is insulating, and the polymer gel is pulled toward the second electrode layer 14A preferentially at the center rather than the side surface of the opening 16, and the light scatterer 15 is formed.
  • the polymer material layer 11 is deformed by the elasticity and voltage response of the polymer gel itself, and a convex light scatterer 15 is formed around the central axis of the opening 16. If the composition of the polymer material layer 11 and the shape of the opening 16 are uniform, by applying the same level of voltage, it is possible to form a light scatterer 15 having a convex shape with less variation in the opening 16.
  • the thickness of the polymer material layer 11 is slightly reduced by the amount of pulling up of the polymer gel in the opening 16.
  • the positions of the spacer layer 13A in surface contact with the polymer material layer 11 and the positions of the second electrode layer 14A supported by the spacer layer 13A are also lowered slightly. .
  • the deformation of the polymer material layer 11 is reversible, and can be returned to the initial state of FIG. 2 (B) by stopping the application of the voltage. Further, as described later, the height of the light scatterer 15 can be adjusted according to the level of the voltage to be applied.
  • the number of openings 16 formed in the spacer layer 13A is not limited to one.
  • the polymer material layer 11 can be deformed by voltage application, and the plurality of light scatterers 15 can be formed. Also in this case, if the composition of the polymer material layer 11 and the shape of the plurality of openings 16 are uniform, it is possible to simultaneously form the plurality of light scatterers 15 of uniform shape by voltage application.
  • FIG. 3 is a schematic view of a microlens array 100 obtained by forming a plurality of light scatterers 15 in the optical element 10A.
  • the microlens array 100 includes a first electrode layer 12A, a second electrode layer 14A, a polymer material layer 11 disposed between the first electrode layer 12A and the second electrode layer 14A, and a polymer.
  • a spacer layer 13A is inserted between the material layer 11 and the second electrode layer 14A.
  • both the first electrode layer 12A and the second electrode layer 14A are transparent electrodes.
  • a plurality of openings 16 are formed in the spacer layer 13A.
  • the polymer material layer 11 is deformed, and the light scatterers 15 are formed in the respective openings 16.
  • the first electrode layer 12A is a cathode layer
  • the second electrode layer 14A is an anode layer
  • an array of light scatterers 15 is formed on the surface of the polymer material layer 11 on the anode side.
  • the thickness of the polymer material layer 11 is 500 ⁇ m
  • the diameter of the bottom of the light scatterer 15 is 150 ⁇ m
  • the height is 50 ⁇ m
  • the pitch between the centers is 200 ⁇ m.
  • the polymer material layer 11 is, as described with reference to FIG. 1, polymer gel such as PC, polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber and the like. It is.
  • a plasticizer such as DBA, DEA, DES, DOP, DEP may be added to the polymer gel.
  • the mixing ratio of the plasticizer is 50 wt% or more, more preferably 75 wt% or more.
  • the light scattering body 15 of the microlens array 100 is formed by the polymer material layer 11 being electrically attracted to and deformed by the second electrode layer 14A in the internal space of the plurality of openings 16, On the surface of the material layer 11, the light scatterers 15 having a uniform convex shape are arranged.
  • the arrangement of the light scatterers 15 appears and / or light
  • the height of the scatterer 15 can be changed.
  • FIG. 4 is a cross-sectional view taken along the line X-X 'of FIG. 3 when no voltage is applied.
  • the surface of the polymer material layer 11 is flat between the first electrode layer 12A and the second electrode layer 14A. A part of the surface of the polymer material layer 11 is in surface contact with the spacer layer 13A, and the other part is exposed in the space 17 in the opening 16 formed in the spacer layer 13A.
  • the diameter ⁇ of the opening 16 is 150 ⁇ m, and the thickness of the spacer layer 13A is 30 ⁇ m.
  • FIG. 5A to 5C are manufacturing process diagrams of a microlens array 100 which is an example of an optical element having a plurality of light scatterers 15.
  • FIG. 5A the first electrode layer 12A is formed on the base material 21, and the polymer material layer 11 is formed on the first electrode layer 12A.
  • the first electrode layer 12A is, for example, a 100 ⁇ m thick ITO film.
  • the polymer material layer 11 is prepared by adding dibutyl adipate (DBA) to PVC so that the mixing ratio is 80 wt% and completely dissolving in a solvent of THF to form a gel solution, and then the gel solution is used as the first electrode It is cast at a thickness of 500 ⁇ m on the layer 12A.
  • DBA which is a plasticizer, tends to have negative ions, and application of a voltage causes the polymer gel to be attracted to the anode.
  • the spacer layer 13A in which the plurality of openings 16 are formed, and the second electrode layer 14A are disposed.
  • a polyimide film having a thickness of 30 ⁇ m is used as the spacer layer 13A.
  • the second electrode layer 14A is an ITO film having a thickness of 100 ⁇ m.
  • the spacer layer 13A and the second electrode layer 14A are bonded in advance to form an electrode assembly 19A.
  • the electrode assembly 19A may be supported on a substrate (not shown).
  • the openings 16 with a diameter of 150 ⁇ m are arranged in a 30 ⁇ 30 matrix.
  • the pitch P of the openings 16 is 200 ⁇ m, and the distance between the adjacent openings 16 and the openings 16 is 50 ⁇ m.
  • the substrate 21 is peeled off to complete the thin film of the microlens array 100. Thereafter, a voltage of a desired level is applied between the first electrode layer 12A and the second electrode layer 14A to generate the light scatterer 15 in the opening 16.
  • FIG. 6 is a 3D image observed while changing the level of the voltage applied to the optical element 10 having the plurality of light scatterers 15. 3D observation is performed using a digital microscope VHX1000 manufactured by Keyence Corporation.
  • FIG. 6A shows an image when the applied voltage is 600V
  • FIG. 6B shows an image when the applied voltage is 700V
  • FIG. 6C shows an image when the applied voltage is 800V. It can be seen that the application of voltage causes the polymer gel to be pulled up from the center.
  • FIG. 7 is a plot of the height of three consecutive light scatterers 15 as a function of voltage application from the 3D image of FIG.
  • the ordinate represents the height from the surface position of the polymer material layer 11 in the initial state (state without application of voltage), the abscissa represents the in-plane position of the opening 16 of the spacer layer 13A, and one grid is 150 ⁇ m. .
  • the height position of the polymer material layer 11 inside the opening 16 is in the vicinity of ⁇ 20 ⁇ m. This is the effect of an error (about ⁇ 20 ⁇ m) in the depth direction where light does not easily enter in optical measurement, and the profile of the polymer material layer 11 in the opening 16 is flat.
  • the polymer gel When the voltage application is 500 V, the polymer gel is largely deformed to form a protrusion with the center of the opening 16 as a central axis. At voltage levels of 600 V and 700 V, the height position of the peak is further increased, and a vertically long convex profile is obtained. The height of the light scatterer 15 at this time reaches 50 ⁇ m. When the voltage application is 800 V, the height position of the peak is slightly reduced, but the width is also reduced and the steepness is further increased. The radius of curvature near the peak is smaller.
  • the optical element 10 (or the microlens array 100) having a desired lens shape can be obtained.
  • the current flowing through the polymer gel is as low as 10 ⁇ A or less, the calorific value is suppressed, and it can withstand long-term use.
  • FIG. 8 is a schematic view of an optical element 10B according to a modification.
  • the insulating spacer layer 13A having the opening 16 is used by being bonded to the flat second electrode layer 14A.
  • an opening 143 is provided in the main surface 141 opposite to the polymer material layer 11 of the second electrode layer 14B, and the sidewall in the main surface 141 and the opening 143 is covered with the insulating spacer layer 13B.
  • the bottom surface 145 of the opening 143 is exposed without being covered by the spacer layer 13B.
  • the second electrode layer 14B having the opening 143 and the spacer layer 13B may be integrally formed as the electrode assembly 19B.
  • the opening 143 can be formed into a desired shape by wet etching or dry etching.
  • the planar shape of the opening 143 is a circle, an ellipse, a polygon or the like having a predetermined diameter.
  • the insulating spacer layer 13B is formed on the entire main surface 141 of the second electrode layer 14B in which the opening 143 is formed, and the spacer layer 13B on the bottom surface 145 of the opening 143 is removed by photolithography and etching.
  • the second electrode layer 14 B is exposed in 143.
  • a predetermined space 17 is formed between the second electrode layer 14 B and the polymer material layer 11 by the spacer layer 13 covering the side wall of the opening 143.
  • the surface of the polymer material layer 11 is flat inside the space 17 when no voltage is applied.
  • the polymer material layer 11 is in surface contact with the spacer layer 13 B in the region other than the opening 143.
  • the optical element 10B of FIG. 8 can also be used as a microlens array by forming a plurality of light scatterers 15.
  • the bottom surface of the opening 143 may be exposed.
  • FIG. 9 is a schematic view of an imaging device 150 using the microlens array 100 of the embodiment.
  • the microlens array 100 any of the optical element 10A of the embodiment and the optical element 10B of the modification may be used.
  • the optical element 10A in which the first electrode layer 12, the polymer material layer 11, the spacer layer 13, and the second electrode layer 14 are stacked in this order is used as the microlens array 100.
  • the imaging device 150 has a microlens array 100 having an array of a plurality of light scatterers 15, and an imaging element array 130 in which a plurality of imaging elements are arrayed.
  • the imaging device is formed of a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS) sensor, or the like.
  • CMOS complementary metal oxide semiconductor
  • Three color filters 131 may be arranged corresponding to the arrangement of the imaging elements. In this example, red (R), green (G) and blue (B) color filters 131R, 131G and 131B are alternately arranged.
  • FIG. 10 is a schematic view of a lighting device 250 using the microlens array 100 of the embodiment.
  • the lighting device 250 includes a light source 230 such as an LED lamp, and a microlens array 100 disposed on the front side of the light source 230 on the output side.
  • a microlens array 100 any of the optical element 10A of the embodiment and the optical element 10B of the modification may be used.
  • the optical element 10A in which the first electrode layer 12, the polymer material layer 11, the spacer layer 13, and the second electrode layer 14 are stacked in this order is used as the microlens array 100.
  • a light scatterer 15 having a desired shape is formed in the space formed by the spacer layer 13 to control the light diffusion, and the diffused light becomes parallel light in a state where the luminance is kept high. It can be converted.
  • optical elements 10A and 10B can be applied to an optical microscope, a lighting device for industrial use, and the like other than the application examples of FIGS. 9 and 10.
  • the microlens array 100 is formed to be 1 mm or less in thickness, and both the anode and the cathode can be made transparent, so application to an ultra-thin camera, head mounted display (HMD), microlens array (MLA) sheet, etc.
  • HMD head mounted display
  • MLA microlens array
  • the present invention can be effectively applied to the medical field such as an endoscope system.
  • the optical element 10 in which the number of the light scatterers 15 is single can also be applied to a light diffusion sheet, a lens sheet, and the like in the field of medicine and image formation.
  • the optical element 10 and the microlens array 100 are light scatterers having various orientation distributions by on / off control of the voltage or adjusting the voltage level without using a complicated mechanism. 15 can be generated.
  • the applied voltage it is desirable that the applied voltage be low. Therefore, the applied voltage is reduced by devising the composition of the polymer material used for the optical element and the microlens array.
  • the driving voltage of the optical element 10 or the microlens array 100 can be obtained by adding an ionic liquid satisfying a predetermined condition to the gel-like polymer material (polymer gel) used in the polymer material layer 11. Reduce.
  • the addition of the ionic liquid can enhance the deformation efficiency of the polymer material.
  • the ionic liquid is a salt composed of a cation (positively charged ion) and an anion (negatively charged ion), and is a liquid at 25 ° C.
  • One of the predetermined conditions is that the ionic liquid has an anion (negative ion) transport number of a certain value or more at 25 ° C. Details of this condition will be described later.
  • the polymer material is, as described above, polyvinyl chloride (PVC), polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber and the like.
  • PVC polyvinyl chloride
  • polymethyl methacrylate polyurethane
  • polystyrene polyvinyl acetate
  • polyvinyl alcohol polycarbonate
  • polyethylene terephthalate polyacrylonitrile
  • silicone rubber polyacrylonitrile
  • the weight ratio of the ionic liquid to such a polymer material is 0.2 wt% or more and 1.5 wt% or less, more preferably 0.3 wt% or more and 1.0 wt% or less.
  • the drive voltage of the optical element or the microlens array can be reduced by mixing this weight ratio of the ionic liquid. This basis will also be described later.
  • a suitable plasticizer may be added to the polymer gel or it may be dissolved in a solvent.
  • a plasticizer dibutyl adipate (DBA: dibutyl adipate), diethyl adipate (DEA: diethyl adipate), diethyl sebacate (DES: diethyl sebacate), dioctyl phthalate (DOP: dioctyl phthalate), diethyl phthalate (DEP: diethyl phthalate) etc.
  • DBA dibutyl adipate
  • DEA diethyl adipate
  • DES diethyl sebacate
  • DOP dioctyl phthalate
  • DEP diethyl phthalate
  • solvent ether solvents such as tetrahydrofuran (THF) can be used.
  • the polymer material to which the ionic liquid is added is applicable to any of the optical element 10A of FIGS. 1 and 2, the optical element 10B of FIG. 8, and the microlens array 100 of FIG.
  • the drive voltage of the polymer material layer 11 can be reduced to 200 V or less, more preferably 150 V or less, by adding an ionic liquid under predetermined conditions to the polymer material.
  • FIG. 11 is a schematic view of a sample 110 for measuring the characteristics of the polymer material to which the ionic liquid is added.
  • FIG. 11 (a) shows a state in which no voltage is applied
  • FIG. 11 (b) shows a state in which a voltage is applied.
  • a sample is prepared in which the polymer material layer 111 is sandwiched between the electrode 112 and the electrode 113.
  • a polymer gel in which PVC having a weight average molecular weight of 230,000 is dissolved in a solvent of tetrahydrofuran (THF) is prepared, and various ionic liquids are added to prepare multiple types of samples.
  • THF tetrahydrofuran
  • the polymer gel of the sample and the comparative example is applied to a thickness of 300 ⁇ m on the electrode 112 serving as the lower electrode.
  • a metal thin film with a thickness of 20 ⁇ m in which a hole with a diameter of 100 ⁇ m is formed is disposed as the upper electrode 113.
  • the voltage applied between the electrode 112 and the electrode 113 is changed between 0 V and 400 V, and the height h of the peak (peak) of the light scatterer 115 protruding from the electrode 113 is measured.
  • the height h is the height from the surface 113 s of the electrode 113.
  • the electrode 112 is a cathode
  • the electrode 113 is an anode.
  • the optical element 10 of the embodiment attracts the polymer gel to the electrode to form the light scatterer 15 in the space using elastic deformation of the polymer gel by voltage application, but the sample 110 in FIG. The same applies in that the light scatterer 115 is formed utilizing elastic deformation by application.
  • the results of the property measurement of the polymer gel obtained for the sample of FIG. 11 can be applied to the configurations of FIGS. 1 to 3 and FIG.
  • FIG. 12 shows the voltage response characteristics of the polymer gel when various ionic liquids are added.
  • the voltage dependency of the peak height h is measured by changing the voltage value applied to the polymer material layer 111.
  • the voltage dependence of peak height is also measured using a polymer gel to which no ionic liquid is added.
  • the weight ratio of EMI-BF 4 to PVC is 0.5 wt%.
  • EMI is a cation and BF 4 is an anion.
  • the weight ratio of OMI-BF 4 to PVC is 0.5 wt%.
  • OMI is a cation and BF 4 is an anion.
  • Line C shows the voltage dependence of the peak height of sample C to which 1-ethyl-3-methylimidazolium dicyanamide (EMI-DCA) is added as an ionic liquid.
  • EMI-DCA 1-ethyl-3-methylimidazolium dicyanamide
  • the weight ratio of EMI-DCA to PVC is 0.5 wt%.
  • EMI is a cation
  • DCA C 2 N 3
  • the weight ratio of TBP-BF 4 to PVC is 0.1 wt%.
  • TBP is a cation, and BF 4 is an anion.
  • Type of ionic liquids are the same as sample D, but the weight ratio of TBP-BF 4 for PVC is 0.5 wt%.
  • TBP is a cation, and BF 4 is an anion.
  • the weight ratio of EMI-TFSI to PVC is 0.5 wt%.
  • EMI is a cation and TFSI is an anion.
  • the weight ratio of TBP-MES to PVC is 0.5 wt%.
  • TBP is a cation and MES is an anion.
  • Line W shows the voltage dependence of the peak height of the PVC polymer gel of sample W to which the ionic liquid is not added as a comparative example.
  • Sample A to which 0.5 wt% of EMI-BF 4 was added as an ionic liquid and Sample B to which 0.5 wt% of OMI-BF 4 was added were polymer material layers when a voltage of 100 V or less was applied.
  • 11 can be driven to a height of 20 ⁇ m or more.
  • the sample A is displaced to a height of less than 40 ⁇ m by application of a voltage of 50 V and a height of 20 ⁇ m and application of a voltage of 200 V.
  • the sample B is also displaced to a height of 25 ⁇ m at a voltage application of 100 V and a height of 30 ⁇ m at a voltage application of 200 V.
  • Sample C added with 0.5 wt% of EMI-DCA can obtain the same 20 ⁇ m peak height with about half applied voltage (210 to 220 V) as compared with sample W to which no ionic liquid is added. The deformation efficiency has been greatly improved.
  • Sample D to which 0.1 wt% of TBP-BF 4 is added, can cause the light scatterer 115 to project from the surface 113 s of the electrode 113 by applying a voltage of 50 V, but the peak height is It remains less than 10 ⁇ m and the change in peak height is small in the range of 50V to 400V. In the sample D, it is difficult to accurately adjust the height of the light scatterer 115 by voltage control.
  • FIG. 13 is a view showing the relationship between the displacement of the polymer gel and the physical properties of the ionic liquid.
  • the samples A to H to which various ionic liquids are added, in which the displacement is positive, indicate that the polymer gel protrudes from the surface 113 s of the electrode 113 by application of a voltage and the light scatterer 115 is formed.
  • the negative displacement is one in which the polymer gel does not protrude from the surface 113s of the electrode 113 even when a voltage is applied.
  • each ionic liquid As physical properties of each ionic liquid, conductivity, size of potential window, diffusion coefficient and transport number of negative ions at 25 ° C. are measured. Since some of the used ionic liquids are solid at 25 ° C., the diffusion coefficient and transport number of negative ions at 80 ° C. are measured for those melted by heating to 80 ° C.
  • the conductivity of sample C is smaller by two orders of magnitude compared with samples A and B, the polymer gel to which sample C is added is positively displaced.
  • sample H is much more conductive than sample C, but the polymer gel is not positively displaced. It is believed that the conductivity of the ionic liquid is not directly related to the deformation efficiency of the polymer gel.
  • the potential window is a potential region where the electrochemical stability is maintained in the system of FIG.
  • the wider the voltage window (the larger the value), the wider the range in which the system is electrochemically stable.
  • the potential windows of the sample A and the sample F are the same width, the polymer gel of the sample A is displaced to the plus, and the polymer gel of the sample F does not obtain the plus displacement.
  • the width of the potential window of the ionic liquid is also considered not to be directly related to the deformation efficiency of the polymer gel.
  • the diffusion coefficient and transport number of anions (negative ions) at 25 ° C. are examined.
  • the diffusion coefficient of positive and negative ions contained in the ionic liquid is measured using solid-state NMR (VNMR System manufactured by Varian) as a measurement instrument.
  • VNMR System manufactured by Varian
  • an ionic liquid is injected into the capillary and set in the apparatus.
  • the signal intensity with respect to the change of the magnetic field is measured at a predetermined temperature (in this case, 25 ° C. and 80 ° C.), and the diffusion coefficients of positive and negative ions are calculated from the Stokes-Einstein equation.
  • the transport number of negative ions represents the ratio of the current carried by the anion to the total current when a current is applied to the ionic liquid.
  • the transport number of the negative ion is calculated as the ratio of the diffusion coefficient of the negative ion to the sum of the diffusion coefficient of the negative ion and the diffusion coefficient of the positive ion determined above (D anion / (D cation + D anion )).
  • the ionic liquids used for the samples A, B, C, F, and H were liquids at 25 ° C., and the diffusion coefficient and transport number of negative ions of each ionic liquid were calculated from the measurement results by liquid chromatography.
  • the transport number of negative ions of the ionic liquid at 25 ° C. is 0.4 or more.
  • the transport number of negative ions at 25 ° C. of the ionic liquid used in samples F and H which can not obtain positive displacement is smaller than 0.4. From this, it is considered that the transport number of negative ions at room temperature influences the deformation efficiency of the polymer gel.
  • the diffusion coefficient can not be measured.
  • this ionic liquid was heated to 80 ° C. and melted, the diffusion coefficient and transport number of negative ions were calculated, and the transport number was 0.6.
  • the anion size and the cation size of the ionic liquid used in sample G are also moderate, the ionic liquid is solid at 25 ° C. Therefore, even if the ionic liquid is dispersed in the polymer gel by stirring, the deformation efficiency of the gel is Is considered to have contributed less.
  • ionic liquids can be used by selecting the thing which does not influence deterioration of a cathode as a cation.
  • Li-BF 4 - may be used as ionic liquids.
  • FIG. 14 is a graph showing the relationship between the amount of ionic liquid added and the displacement of the polymer gel.
  • the abscissa represents the content (wt%) of the ionic liquid relative to the polymer material of the polymer gel, and the ordinate represents the peak height of the displacement.
  • EMI-BF 4 of sample A is used as the ionic liquid.
  • the amount of EMI-BF 4 added is varied in the range of 0 wt% to 5.0 wt%. Further, the applied voltage is changed to 0V, 50V, 100V, 200V, and 400V.
  • positive displacement can be obtained when the amount of ionic liquid added is in the range of 0.2 wt% to 1.5 wt%. In addition, the displacement is maximized in the range of 0.3 wt% to 1.0 wt%.
  • the light scatterer 115 can be formed on the surface 113 s of the electrode 113 by applying a voltage of 100 V or less.
  • the addition amount of the ionic liquid is 5.0 wt%, a memory phenomenon occurs in which the deformation does not return even when the voltage is turned off.
  • the weight ratio of the ionic liquid to the polymer is preferably 0.2 wt% to 1.5 wt%, more preferably 0.3 wt% to 1.0 wt%. This is also in agreement with the result of FIG.
  • FIG. 15 is a view showing the evaluation results of the light diffusion distribution of the light scatterer 115 formed by applying a voltage to the polymer material layer 111 for each addition amount of the ionic liquid.
  • the sample 110 of FIG. 11 is manufactured using the polymer material layer 111 in which EMI-BF 4 is used as the ionic liquid and the addition amount of EMI-BF 4 is changed.
  • the polymer material layer 111 contains PVC as a polymer gel and dibutyl adipate (DBA) as a plasticizer.
  • DBA dibutyl adipate
  • An electrode 112 to be a cathode is formed of ITO with a thickness of 150 ⁇ m, and a voltage is applied to the polymer material layer 111 sandwiched between the electrode 112 and the electrode 113 to form a light scatterer 115.
  • the laser is disposed on the side of the electrode 112 formed of ITO, and the screen is disposed on the side on which the light scatterer 115 is formed. Laser light of red parallel light is incident on the sample 110 from the back surface side of the electrode 112, and the light diffusion state on the screen is observed.
  • the screen is disposed on the light exit side of the light scatterer 115 at a position farther than the focal point of the light scatterer 115.
  • the light diffusion once focused at the focal point of the light scatterer 115 is observed on the screen.
  • the diameter of the light scatterer 115 of the sample 110 is as small as 100 ⁇ m and the height is as small as about 0 to 40 ⁇ m, and the focal position thereof is very close to the light scatterer 115 and observation with the naked eye is difficult. By observing light diffusion at a position beyond the focus of the light scatterer 115, it is possible to evaluate the light collection state.
  • the light scatterer 115 protruding from the surface of the electrode 113 is not formed even when a voltage of 200 V is applied.
  • the red collimated light incident from the back surface of the sample 110 passes through the sample 110 as collimated light without being collected. In the range of 0 V to 400 V, spots of the same size are formed on the screen regardless of the level of applied voltage.
  • a voltage of 100 V causes a slight swelling of the polymer gel on the surface of the electrode 113, but the light collecting function is insufficient and almost parallel light at the screen position The spot of is maintained.
  • a voltage of 200 V By applying a voltage of 200 V, a light scatterer 115 (having a gentle curvature) having a peak height of about 10 ⁇ m is formed. The light once collected at the focal position of the light scatterer 115 diffuses and spreads, and no spot appears on the screen.
  • a light scatterer 115 is formed on the surface of the electrode 113 by applying a voltage of 50 V, and light which has started to be diffused after being collected is observed at the screen position .
  • the light scatterer 115 having a peak height larger than that at the time of 50 V application, ie, a sharp curvature, is formed on the surface of the electrode 113.
  • the light incident from the back side of the sample 110 is greatly diffused after being collected, and no spot is observed at the screen position.
  • the focal length of the light scatterer 115 can be made variable by adjusting the applied voltage.
  • the light scatterer 115 can be formed with a lower voltage, and as a variable focus lens or a variable shape lens with good deformation efficiency. It can be used.
  • FIG. 16 is a view showing the influence of the ionic liquid on the cathode degradation.
  • a PVC gel to which various ionic liquids are added is applied on a metal substrate, and an ITO electrode is disposed on the PVC gel as a counter electrode.
  • the types of PVC gel to be applied are Sample A (containing 0.5 wt% EMI-BF 4 ), Sample B (containing 0.5 wt% OMI-BF 4 ), Sample C (0.5 wt% EMI-DCA), Sample D (with 0.1 wt% TBP-BF 4 ), Sample H (with 0.5 wt% EMI-FSI), and Sample G (0.5 wt%) (Including TBP-MES).
  • Sample A to D have obtained positive displacement in FIG.
  • Sample D is a sample in which the added amount is reduced to 0.1 wt% because displacement is not obtained when the weight ratio of the ionic liquid is set to 0.5 wt% the same as the other samples.
  • the surface condition of the electrode is observed from the ITO side while changing the voltage level applied to the PVC gel by using a metal substrate as a positive electrode and ITO as a negative electrode.
  • the polymeric material to which the ionic liquid is added is applicable to the microlens array 100 of FIG. 3 as described above.
  • an array of light scatterers 15 can be formed in the space 17 by applying a voltage of 200 V or less between the electrodes 12A and 14A.
  • an array of light scatterers 15 having a height of 20 ⁇ m or more can be formed by applying a voltage of 100 V or less.
  • the present invention has been described above based on the specific embodiments, the present invention is not limited to the above-described configuration examples.
  • the arrangement of the light scatterers 15 is not limited to the matrix arrangement, and may be alternately arranged.
  • the shape of the openings 16 (or 143) of the spacer layer 13A may be hexagonal and finely arranged.

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Abstract

Provided are: an optical element having a simple structure and with which the optical properties thereof can be adjusted; and a method for producing same. This optical element (10A) comprises: a first electrode layer (12A); a second electrode layer (14A); a polymer material layer (11) positioned in between the first electrode layer (12A) and the second electrode layer (14A); and an insulating spacer layer (13A) positioned between the polymer material layer (11) and the second electrode layer (14A), to form a predetermined space (17) between the polymer material layer (11) and the second electrode layer (14A). The polymer material layer (11) deforms when a voltage is applied, to form one or more light-scattering bodies (15) in the predetermined space.

Description

光学素子、及び光学素子の作製方法Optical element and method of manufacturing optical element
　本発明は、光学素子、及び光学素子の作製方法に関する。 The present invention relates to an optical element and a method of manufacturing the optical element.
　従来から、電圧の印加によって変形する高分子材料を用いて、レンズを光軸方向に移動させる焦点調節機構（たとえば、特許文献１参照）、レンズ駆動機構（たとえば、特許文献２参照）等が知られている。高分子材料はレンズを保持するレンズホルダに用いられており、電圧印加による高分子材料の伸縮を利用して、レンズの位置を光軸に沿って動かしている。 Conventionally, a focusing mechanism (see, for example, Patent Document 1), a lens driving mechanism (see, for example, Patent Document 2), and the like that move a lens in the optical axis direction using a polymeric material that deforms by application of a voltage It is done. A polymer material is used for a lens holder for holding a lens, and the position of the lens is moved along the optical axis by using expansion and contraction of the polymer material by applying a voltage.
　また、電界の印加方向に伸縮する有機材料を一対の電極で挟み、有機材料層の電界印加方向と垂直な面内で単位電場当たりの電歪性歪量に分布を持たせることで、有機材料層と電極を変形させて凸レンズ、凹レンズ等を形成する方法が提案されている（たとえば、特許文献３参照）。 In addition, an organic material can be obtained by sandwiching an organic material that expands and contracts in the application direction of the electric field with a pair of electrodes, and providing an electrostrictive strain amount per unit electric field in a plane perpendicular to the application direction of the organic material layer. A method of forming a convex lens, a concave lens and the like by deforming a layer and an electrode has been proposed (see, for example, Patent Document 3).
　人工筋肉アクチュエータに適用される高分子柔軟アクチュエータとして、ポリ塩化ビニル１～５０重量部に対してイオン液体を１～３０重量部含むゲル材料が知られている（たとえば、特許文献４参照）。 As a polymer flexible actuator applied to an artificial muscle actuator, a gel material containing 1 to 30 parts by weight of an ionic liquid to 1 to 50 parts by weight of polyvinyl chloride is known (see, for example, Patent Document 4).
特許第４５３０１６３号Patent No. 4530163 特許第５１８０１１７号Patent No. 5180117 特許第５０２９１４０号Patent No. 5029140 特許第５３９２６６０号Patent No. 5392660
　レンズを光軸に沿って移動させる構成は、レンズホルダに配置された高分子材料を伸縮させることで、単一のレンズの位置を変化させている。この構成は、まずホルダを変形させ、ホルダの変形によってレンズ位置を変えるので、レンズ駆動の応答性と精度を十分に高めることが難しい。 The configuration in which the lens is moved along the optical axis changes the position of a single lens by expanding and contracting the polymer material disposed in the lens holder. In this configuration, the holder is first deformed, and the lens position is changed by the deformation of the holder, so it is difficult to sufficiently improve the responsiveness and accuracy of the lens drive.
　有機材料層の面内方向に電歪性歪量の分布を持たせる構成は、インクジェットやマイクロコンタクトプリンティングなどで、特性の異なる材料を微小量ずつ所望の位置に塗布するため、レンズ作製の工程が複雑であり時間がかかる。 In the configuration in which the distribution of the electrostrictive strain amount is given in the in-plane direction of the organic material layer, a minute amount of material having different characteristics is applied to a desired position by ink jet or micro contact printing. Complex and time consuming.
　また、上述した従来構成はいずれも単一のレンズの調整を目的としているが、イメージングや映像関連製品では、多数の微細なレンズを用いたマイクロレンズアレイに対する需要が高まっている。マイクロレンズアレイに焦点調整機能を付与することができれば、付加価値を高めることができる。 In addition, although all the conventional configurations described above aim at adjusting a single lens, in imaging and image related products, the demand for a microlens array using a large number of fine lenses is increasing. If the microlens array can be provided with a focusing function, added value can be increased.
　上記の課題に鑑みて、本発明は、簡単な構成で光学特性を調整することのできる光学素子とその作製方法を提供することを目的とする。 In view of the above problems, the present invention has an object to provide an optical element capable of adjusting optical characteristics with a simple configuration and a method of manufacturing the same.
　本発明では、電圧印加による高分子材料の伸縮または変形を利用して、光の集光・拡散を制御することのできる光学素子を提供する。 The present invention provides an optical element capable of controlling light collection and diffusion by using expansion and contraction or deformation of a polymer material by voltage application.
　第１の態様では、光学素子は、
　第１の電極層と、
　第２の電極層と、
　前記第１の電極層と前記第２の電極層の間に配置される高分子材料層と、
　前記高分子材料層と前記第２の電極層の間に配置され、前記高分子材料層と前記第２の電極層の間に所定の空間を形成する絶縁性のスペーサ層と、
を有し、前記高分子材料層は、電圧印加の下で変形して、前記所定の空間に１以上の光散乱体を形成する。 In a first aspect, the optical element
A first electrode layer,
A second electrode layer,
A polymer material layer disposed between the first electrode layer and the second electrode layer;
An insulating spacer layer disposed between the polymer material layer and the second electrode layer to form a predetermined space between the polymer material layer and the second electrode layer;
The polymer material layer deforms under voltage application to form one or more light scatterers in the predetermined space.
　第２の態様では、光学素子の作製方法は、
　第１の電極層の上に高分子材料層を形成し、
　前記高分子材料層の上に、絶縁性のスペーサ層と第２の電極層とを配置して、前記高分子材料層と前記第２の電極層の間に所定の空間を形成し、
　前記第１の電極層と前記第２の電極層の間に電圧を印加して前記高分子材料層を変形させて、前記空間に１以上の光散乱体を形成する、
工程を含む。 In a second aspect, a method of manufacturing an optical element is
Forming a polymer material layer on the first electrode layer;
An insulating spacer layer and a second electrode layer are disposed on the polymer material layer to form a predetermined space between the polymer material layer and the second electrode layer,
A voltage is applied between the first electrode layer and the second electrode layer to deform the polymer material layer to form one or more light scatterers in the space.
Including the steps.
　上記の構成と手法により、簡単な構成で光学特性を調整することのできる光学素子とその作製方法が実現される。 With the above-described configuration and method, an optical element capable of adjusting optical characteristics with a simple configuration and a method of manufacturing the same can be realized.
実施形態の光学素子の基本構成を示す概略模式図である。It is a schematic diagram which shows the basic composition of the optical element of embodiment. 実施形態の光学素子の動作原理を説明する図である。It is a figure explaining the operation principle of the optical element of an embodiment. 実施形態の光学素子に複数の光散乱体を形成して得られるマイクロレンズアレイの概略図である。It is the schematic of the microlens array obtained by forming several light-scattering bodies in the optical element of embodiment. 図３のＸ－Ｘ’断面図である。FIG. 4 is a cross-sectional view taken along line X-X ′ of FIG. 3; 複数の光散乱体を有する光学素子の作製工程図である。It is a manufacturing-process figure of the optical element which has several light-scattering bodies. 複数の光散乱体を有する光学素子の作製工程図である。It is a manufacturing-process figure of the optical element which has several light-scattering bodies. 複数の光散乱体を有する光学素子の作製工程図である。It is a manufacturing-process figure of the optical element which has several light-scattering bodies. 実施形態の光学素子の変形過程を示す３Ｄ画像である。It is a 3D image which shows the deformation process of the optical element of embodiment. 図６の光学素子（マイクロレンズアレイ）の断面プロファイルを電圧の関数として示す図である。It is a figure which shows the cross-sectional profile of the optical element (micro lens array) of FIG. 6 as a function of voltage. 光学素子の変形例と動作を示す図である。It is a figure which shows the modification of an optical element, and operation | movement. 実施形態の光学素子を用いた撮像装置の模式図である。It is a schematic diagram of an imaging device using an optical element of an embodiment. 実施形態の光学素子を用いた照明装置の模式図である。It is a schematic diagram of the illuminating device using the optical element of embodiment. イオン液体を添加した高分子材料の特性を測定するためのサンプルの模式図である。It is a schematic diagram of the sample for measuring the characteristic of the polymeric material which added the ionic liquid. 図１１のサンプルで高分子材料に種々のイオン液体を添加したときの高分子材料層の応答特性を示す図である。It is a figure which shows the response characteristic of a polymeric material layer when various ionic liquids are added to a polymeric material by the sample of FIG. イオン液体の物性とポリマーゲルの変位状態を示す図である。It is a figure which shows the physical property of an ionic liquid, and the displacement state of a polymer gel. イオン液体の添加量とポリマーゲルの変位の関係を示す図である。It is a figure which shows the relationship between the addition amount of an ionic liquid, and the displacement of a polymer gel. 電圧印加により形成された光散乱体の評価結果をイオン液体の添加量ごとに示す図である。It is a figure which shows the evaluation result of the light-scattering body formed by voltage application for every addition amount of an ionic liquid. イオン液体の電極劣化への影響を示す図である。It is a figure which shows the influence on the electrode degradation of an ionic liquid.
　図１は、実施形態の光学素子１０の一つの構成例として、光学素子１０Ａの基本構成を示す。光学素子１０Ａは、第１の電極層１２と、第２の電極層１４Ａと、第１の電極層１２と第２の電極層１４Ａの間に配置される高分子材料層１１と、高分子材料層１１と第２の電極層１４Ａの間に配置されるスペーサ層１３Ａを有する。スペーサ層１３Ａは、所定のパターンの開口１６を有し、開口１６の位置で、高分子材料層１１と第２の電極層１４Ａの間に、空間１７が形成されている。 FIG. 1 shows a basic configuration of an optical element 10A as one configuration example of the optical element 10 according to the embodiment. The optical element 10A includes a first electrode layer 12, a second electrode layer 14A, a polymer material layer 11 disposed between the first electrode layer 12 and the second electrode layer 14A, and a polymer material. A spacer layer 13A is disposed between the layer 11 and the second electrode layer 14A. The spacer layer 13A has an opening 16 of a predetermined pattern, and a space 17 is formed between the polymer material layer 11 and the second electrode layer 14A at the position of the opening 16.
　高分子材料層１１は、電圧印加の下で弾性変形して、空間１７の中に光散乱体１５を形成する。光散乱体１５は、後述するように凸形状を有している。 The polymeric material layer 11 elastically deforms under voltage application to form the light scatterer 15 in the space 17. The light scatterer 15 has a convex shape as described later.
　スペーサ層１３Ａは、電気的に絶縁性であれば、材料の種類を問わない。無機絶縁膜、有機絶縁膜のいずれであってもよい。図１の例では、スペーサ層１３Ａは、所定の開口１６のパターンを有する絶縁性の樹脂膜である。開口１６の平面形状と寸法は、空間１７の体積と、空間１７の中に発生させる光散乱体１５の形状によって適宜設計され、一例として、円、楕円、多角形等である。 The spacer layer 13A may be of any material as long as it is electrically insulating. It may be either an inorganic insulating film or an organic insulating film. In the example of FIG. 1, the spacer layer 13A is an insulating resin film having a predetermined pattern of the openings 16. The planar shape and dimensions of the opening 16 are appropriately designed according to the volume of the space 17 and the shape of the light scatterer 15 generated in the space 17, and are, for example, a circle, an ellipse, a polygon or the like.
　スペーサ層１３Ａの開口１６の径は、たとえば１ｍｍ未満、好ましくは３００μｍ以下に設定される。開口１６の径が１ｍｍ以上になると、電圧の印加によって、開口１６内に高分子材料層１１を突出させることが困難になる。開口１６の径を３００μｍ以下にする場合は、電圧印加に対する高分子材料層１１の変形効率が向上し、凸形状を形成することができる。 The diameter of the opening 16 of the spacer layer 13A is set to, for example, less than 1 mm, preferably 300 μm or less. When the diameter of the opening 16 is 1 mm or more, it becomes difficult to project the polymer material layer 11 into the opening 16 by application of a voltage. When the diameter of the opening 16 is 300 μm or less, the deformation efficiency of the polymer material layer 11 with respect to voltage application is improved, and a convex shape can be formed.
　高分子材料層１１と光散乱体１５は、ゲル状のポリマー材料（以下、適宜「ポリマーゲル」と呼ぶ）で形成されている。光散乱体１５は、電圧の印加によるポリマーゲルの伸縮または変形を利用して形成されている。 The polymer material layer 11 and the light scattering body 15 are formed of a gel-like polymer material (hereinafter, appropriately referred to as “polymer gel”). The light scatterer 15 is formed by using expansion and contraction or deformation of the polymer gel by application of a voltage.
　ポリマーゲルは、ポリ塩化ビニル（ＰＶＣ：polyvinyl chloride）、ポリメタクリル酸メチル、ポリウレタン、ポリスチレン、ポリ酢酸ビニル、ポリビニルアルコール、ポリカーボネート、ポリエチレンテレフタレート、ポリアクリロニトリル、シリコーンゴム等であり、使用波長に対して透明な高分子（または樹脂）材料を適宜選択することができる。 The polymer gel is polyvinyl chloride (PVC), polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber, etc., and is transparent to the used wavelength. Polymer (or resin) material can be selected appropriately.
　実施形態では、電場の作用による変形例が大きく、取扱いが容易なＰＶＣを用いる。ＰＶＣに適切な可塑剤を添加してもよいし、ＰＶＣを溶媒に溶解させてもよい。可塑剤を用いる場合は、アジピン酸ジブチル（ＤＢＡ：dibutyl adipate）、アジピン酸ジエチル（ＤＥＡ：diethyl adipate）、セバシン酸ジエチル（ＤＥＳ：diethyl sebacate）、フタル酸ジオクチル（ＤＯＰ：dioctyl phthalate）、フタル酸ジエチル（ＤＥＰ：diethyl phthalate）等を用いることができる。溶媒として、テトラヒドロフラン（ＴＨＦ）等を用いることができる。 In the embodiment, PVC which is easily modified due to the action of the electric field is used. A suitable plasticizer may be added to PVC, or PVC may be dissolved in a solvent. When a plasticizer is used, dibutyl adipate (DBA: dibutyl adipate), diethyl adipate (DEA: diethyl adipate), diethyl sebacate (DES: diethyl sebacate), dioctyl phthalate (DOP: dioctyl phthalate), diethyl phthalate (DEP: diethyl phthalate) etc. can be used. Tetrahydrofuran (THF) etc. can be used as a solvent.
　可塑剤の混合比率は５０ｗｔ％以上、好ましくは７５ｗｔ％以上である。混合比率が５０ｗｔ％未満だと、電圧を印加しても高分子材料層１１を変形させることが困難になる。混合比率が５０ｗｔ％以上７５ｗｔ％未満のときは、電圧印加により高分子材料層１１を変形させることができるが、印加する電圧レベルが高くなるおそれがある。混合比率を７５ｗｔ％以上とすることで、適切な電圧レベルで高分子材料層１１を変形させることができる。 The mixing ratio of the plasticizer is 50 wt% or more, preferably 75 wt% or more. If the mixing ratio is less than 50 wt%, it becomes difficult to deform the polymer material layer 11 even if a voltage is applied. When the mixing ratio is 50 wt% or more and less than 75 wt%, the polymer material layer 11 can be deformed by voltage application, but the voltage level to be applied may be high. By setting the mixing ratio to 75 wt% or more, the polymer material layer 11 can be deformed at an appropriate voltage level.
　第１の電極層１２は、導電性を有する材料であれば、特に制限はない。第１の電極層１２を金属で形成する場合は、白金、金、銀、ニッケル、クロム、銅、チタン、タンタル、インジウム、パラジウム、リチウム、ニオブ、これらの合金などを用いることができる。第１の電極層１２をＩＴＯ（Indium Tin Oxide：酸化インジウムスズ）等の透明な酸化物半導体材料で形成してもよいし、導電性ポリマー、導電性カーボン等を用いてもよい。 The first electrode layer 12 is not particularly limited as long as it is a conductive material. When the first electrode layer 12 is formed of a metal, platinum, gold, silver, nickel, chromium, copper, titanium, tantalum, indium, palladium, lithium, niobium, an alloy of these, or the like can be used. The first electrode layer 12 may be formed of a transparent oxide semiconductor material such as ITO (Indium Tin Oxide: indium tin oxide), or a conductive polymer, conductive carbon, or the like may be used.
　第２の電極層１４Ａは、透明電極層であるのが望ましい。第２の電極層１４Ａを透明電極層とすることで、光散乱体１５で集光または拡散される光を透過させることができる。 The second electrode layer 14A is preferably a transparent electrode layer. By using the second electrode layer 14A as a transparent electrode layer, light collected or diffused by the light scatterer 15 can be transmitted.
　第１の電極層１２と第２の電極層１４Ａの極性は、高分子材料層１１の形状を変化させる方向に応じて設定することができる。図１の例では、高分子材料層１１は、マイナスに帯電しやすい材料を用い、第１の電極層１２を陰極、第２の電極層１４Ａを陽極としている。 The polarities of the first electrode layer 12 and the second electrode layer 14A can be set according to the direction in which the shape of the polymer material layer 11 is changed. In the example of FIG. 1, the polymer material layer 11 is made of a material that is easily negatively charged, the first electrode layer 12 is a cathode, and the second electrode layer 14A is an anode.
　高分子材料層１１の陽極側の表面の一部は、スペーサ層１３Ａと面接触している。高分子材料層１１は、電圧印加により、スペーサ層１３Ａと面接触していない領域（すなわち開口１６内に露出している領域）で変形し、第２の電極層１４Ａに向かって引き上げられる。 A part of the surface on the anode side of the polymer material layer 11 is in surface contact with the spacer layer 13A. The polymer material layer 11 is deformed in a region not in surface contact with the spacer layer 13A (ie, a region exposed in the opening 16) by application of a voltage, and is pulled toward the second electrode layer 14A.
　光学素子１０Ａは、たとえば以下の手順で作製することができる。所定の寸法に形成された第１の電極層１２の上に、可塑剤が添加されたＰＶＣの溶液をキャスト法等で塗布して、高分子材料層１１を形成する。高分子材料層１１の上に、あらかじめ開口１６のパターンを形成したスペーサ層１３Ａと、第２の電極層１４Ａを配置する。スペーサ層１３Ａの配置と、第２の電極層１４Ａの配置は、同時でも、順次でもよい。 The optical element 10A can be manufactured, for example, by the following procedure. On the first electrode layer 12 formed to a predetermined size, a solution of PVC to which a plasticizer is added is applied by a cast method or the like to form a polymer material layer 11. On the polymer material layer 11, the spacer layer 13A in which the pattern of the openings 16 is formed in advance and the second electrode layer 14A are disposed. The arrangement of the spacer layer 13A and the arrangement of the second electrode layer 14A may be simultaneous or sequentially.
　第１の電極層１２と第２の電極層１４Ａの間に所定の電圧を印加して、開口１６によって形成される空間１７内に光散乱体１５を形成する。 A predetermined voltage is applied between the first electrode layer 12 and the second electrode layer 14 A to form the light scatterer 15 in the space 17 formed by the opening 16.
　高分子材料層１１の厚さは、開口１６の径と深さ、形成したい光散乱体１５の高さ、第１の電極層１２及び第２の電極層１４Ａの厚さ等に応じて適宜決定される。一例として、高分子材料層１１の厚さは１ｍｍ以下、好ましくは０．１ｍｍ～０．５ｍｍである。高分子材料層１１の厚さが０．１ｍｍ以下のときは、多少、ハンドリングしにくくなるが、あくまでも開口１６のサイズとの兼ね合いで設計される。したがって、微細な多数のレンズを有するマイクロレンズアレイシートを作製する場合は、高分子材料層１１の厚さが０．１ｍｍ以下になる場合もあり得る。スペーサ層１３Ａの厚さは１ｍｍ以下、好ましくは０．１ｍｍ以下である。 The thickness of the polymer material layer 11 is appropriately determined in accordance with the diameter and depth of the opening 16, the height of the light scatterer 15 to be formed, the thickness of the first electrode layer 12 and the thickness of the second electrode layer 14A, etc. Be done. As an example, the thickness of the polymer material layer 11 is 1 mm or less, preferably 0.1 mm to 0.5 mm. When the thickness of the polymer material layer 11 is 0.1 mm or less, it becomes somewhat difficult to handle, but it is designed in consideration of the size of the opening 16 to the last. Therefore, in the case of producing a microlens array sheet having a large number of fine lenses, the thickness of the polymer material layer 11 may be 0.1 mm or less. The thickness of the spacer layer 13A is 1 mm or less, preferably 0.1 mm or less.
　図２は、実施形態の光学素子１０Ａの動作原理を説明する図である。図２の（ａ）は電圧が印加されていない状態を示す。図２の（ｂ）は電圧が印加されたときの状態を示す。 FIG. 2 is a diagram for explaining the operation principle of the optical element 10A of the embodiment. (A) of FIG. 2 shows the state to which the voltage is not applied. (B) of FIG. 2 shows the state when a voltage is applied.
　図２の（ａ）の状態では、高分子材料層１１は表面が平坦な状態で第１の電極層１２と第２の電極層１４Ａの間に位置する。高分子材料層１１と第２の電極層１４Ａの間にスペーサ層１３Ａが設けられているので、高分子材料層１１の一部は、スペーサ層１３Ａと面接触している。スペーサ層１３Ａに形成された開口１６の位置では、高分子材料層１１と第２の電極層１４Ａの間に空間１７が形成されている。 In the state of FIG. 2A, the polymer material layer 11 is positioned between the first electrode layer 12 and the second electrode layer 14A in a state where the surface is flat. Since the spacer layer 13A is provided between the polymer material layer 11 and the second electrode layer 14A, a part of the polymer material layer 11 is in surface contact with the spacer layer 13A. At the position of the opening 16 formed in the spacer layer 13A, a space 17 is formed between the polymer material layer 11 and the second electrode layer 14A.
　図２の（ｂ）のように、第１の電極層１２と第２の電極層１４Ａの間に電圧が印加されると、陰極である第１の電極層１２からゲル状の高分子材料層１１に電子が注入される。電子を含むポリマーゲルは、陽極である第２の電極層１４Ａの表面に向かって引き上げられる。一方、スペーサ層１３Ａは絶縁性であり、ポリマーゲルは、開口１６の側面よりも中心部で優先的に、第２の電極層１４Ａに向かって引っ張られ、光散乱体１５が形成される。 As shown in FIG. 2B, when a voltage is applied between the first electrode layer 12 and the second electrode layer 14A, a gel polymer material layer is formed from the first electrode layer 12 which is a cathode. Electrons are injected into 11. The polymer gel containing electrons is pulled toward the surface of the second electrode layer 14A which is an anode. On the other hand, the spacer layer 13A is insulating, and the polymer gel is pulled toward the second electrode layer 14A preferentially at the center rather than the side surface of the opening 16, and the light scatterer 15 is formed.
　高分子材料層１１は、ポリマーゲル自体が持つ弾性と電圧応答性によって変形し、開口１６の中心軸のまわりに、凸形状の光散乱体１５が形成される。高分子材料層１１の組成と開口１６の形状が均一であれば、同じレベルの電圧を印加することで、開口１６内に、ばらつきの少ない凸形状の光散乱体１５を形成することができる。 The polymer material layer 11 is deformed by the elasticity and voltage response of the polymer gel itself, and a convex light scatterer 15 is formed around the central axis of the opening 16. If the composition of the polymer material layer 11 and the shape of the opening 16 are uniform, by applying the same level of voltage, it is possible to form a light scatterer 15 having a convex shape with less variation in the opening 16.
　トータルのポリマーゲルの体積は同じであるから、開口１６内でポリマーゲルが引き上げられた分だけ、高分子材料層１１の厚さが若干、低減する。高分子材料層１１の厚さが低減すると、高分子材料層１１と面接触しているスペーサ層１３Ａと、スペーサ層１３Ａに支持されている第２の電極層１４Ａの位置も若干、下方に下がる。 Since the total volume of the polymer gel is the same, the thickness of the polymer material layer 11 is slightly reduced by the amount of pulling up of the polymer gel in the opening 16. When the thickness of the polymer material layer 11 is reduced, the positions of the spacer layer 13A in surface contact with the polymer material layer 11 and the positions of the second electrode layer 14A supported by the spacer layer 13A are also lowered slightly. .
　高分子材料層１１の変形は可逆的であり、電圧の印加を停止することで、図２（Ｂ）の初期状態に戻すことができる。また、後述するように、印加する電圧のレベルに応じて、光散乱体１５の高さを調整することができる。 The deformation of the polymer material layer 11 is reversible, and can be returned to the initial state of FIG. 2 (B) by stopping the application of the voltage. Further, as described later, the height of the light scatterer 15 can be adjusted according to the level of the voltage to be applied.
　スペーサ層１３Ａに形成される開口１６の数は１つに限定されない。スペーサ層１３Ａに複数の開口１６を形成することで、電圧印加により高分子材料層１１を変形させて、複数の光散乱体１５を形成することができる。この場合も、高分子材料層１１の組成と複数の開口１６の形状が均一であれば、電圧印加により、均一な形状の複数の光散乱体１５を同時に形成することができる。 The number of openings 16 formed in the spacer layer 13A is not limited to one. By forming the plurality of openings 16 in the spacer layer 13A, the polymer material layer 11 can be deformed by voltage application, and the plurality of light scatterers 15 can be formed. Also in this case, if the composition of the polymer material layer 11 and the shape of the plurality of openings 16 are uniform, it is possible to simultaneously form the plurality of light scatterers 15 of uniform shape by voltage application.
　図３は、光学素子１０Ａに複数の光散乱体１５を形成して得られるマイクロレンズアレイ１００の概略図である。マイクロレンズアレイ１００は、第１の電極層１２Ａと、第２の電極層１４Ａと、第１の電極層１２Ａと第２の電極層１４Ａの間に配置される高分子材料層１１と、高分子材料層１１と第２の電極層１４Ａの間に挿入されるスペーサ層１３Ａを有する。図３の例では、第１の電極層１２Ａと、第２の電極層１４Ａは、ともに透明電極である。 FIG. 3 is a schematic view of a microlens array 100 obtained by forming a plurality of light scatterers 15 in the optical element 10A. The microlens array 100 includes a first electrode layer 12A, a second electrode layer 14A, a polymer material layer 11 disposed between the first electrode layer 12A and the second electrode layer 14A, and a polymer. A spacer layer 13A is inserted between the material layer 11 and the second electrode layer 14A. In the example of FIG. 3, both the first electrode layer 12A and the second electrode layer 14A are transparent electrodes.
　スペーサ層１３Ａには、複数の開口１６が形成されている。第１の電極層１２Ａと第２の電極層１４Ａの間に電圧が印加されると、高分子材料層１１が変形し、各開口１６内に光散乱体１５が形成される。 A plurality of openings 16 are formed in the spacer layer 13A. When a voltage is applied between the first electrode layer 12A and the second electrode layer 14A, the polymer material layer 11 is deformed, and the light scatterers 15 are formed in the respective openings 16.
　第１の電極層１２Ａは陰極層、第２の電極層１４Ａは陽極層であり、高分子材料層１１の陽極側の表面に、光散乱体１５の配列が形成されている。一例として、高分子材料層１１の厚さは５００μｍ、光散乱体１５の底面の径は１５０μｍ、高さは５０μｍ、中心心間のピッチは２００μｍである。 The first electrode layer 12A is a cathode layer, and the second electrode layer 14A is an anode layer. On the surface of the polymer material layer 11 on the anode side, an array of light scatterers 15 is formed. As an example, the thickness of the polymer material layer 11 is 500 μm, the diameter of the bottom of the light scatterer 15 is 150 μm, the height is 50 μm, and the pitch between the centers is 200 μm.
　高分子材料層１１は、図１を参照して説明したように、ＰＣ、ポリメタクリル酸メチル、ポリウレタン、ポリスチレン、ポリ酢酸ビニル、ポリビニルアルコール、ポリカーボネート、ポリエチレンテレフタレート、ポリアクリロニトリル、シリコーンゴム等のポリマーゲルである。ポリマーゲルに、ＤＢＡ、ＤＥＡ、ＤＥＳ、ＤＯＰ、ＤＥＰ等の可塑剤を添加してもよい。可塑剤の混合比は、５０ｗｔ％以上、より好ましくは７５ｗｔ％以上である。 The polymer material layer 11 is, as described with reference to FIG. 1, polymer gel such as PC, polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber and the like. It is. A plasticizer such as DBA, DEA, DES, DOP, DEP may be added to the polymer gel. The mixing ratio of the plasticizer is 50 wt% or more, more preferably 75 wt% or more.
　マイクロレンズアレイ１００の光散乱体１５は、複数の開口１６の内部空間で、高分子材料層１１が第２の電極層１４Ａに電気的に引きつけられて変形することで形成されており、高分子材料層１１の表面に、均一な凸形状の光散乱体１５が並んでいる。 The light scattering body 15 of the microlens array 100 is formed by the polymer material layer 11 being electrically attracted to and deformed by the second electrode layer 14A in the internal space of the plurality of openings 16, On the surface of the material layer 11, the light scatterers 15 having a uniform convex shape are arranged.
　図２を参照して説明したように、第１の電極層１２Ａと第２の電極層１４Ａの間に印加する電圧のレベルに応じて、光散乱体１５の配列を出現させ、及び／または光散乱体１５の高さを変更することができる。 As described with reference to FIG. 2, depending on the level of the voltage applied between the first electrode layer 12A and the second electrode layer 14A, the arrangement of the light scatterers 15 appears and / or light The height of the scatterer 15 can be changed.
　図４は、電圧が印加されていないときの図３のＸ－Ｘ’断面図である。第１の電極層１２Ａと第２の電極層１４Ａの間で、高分子材料層１１の表面は平坦である。高分子材料層１１の表面の一部はスペーサ層１３Ａと面接触し、その他の部分は、スペーサ層１３Ａに形成された開口１６内の空間１７に露出している。開口１６の径φは１５０μｍ、スペーサ層１３Ａの厚さは３０μｍである。 FIG. 4 is a cross-sectional view taken along the line X-X 'of FIG. 3 when no voltage is applied. The surface of the polymer material layer 11 is flat between the first electrode layer 12A and the second electrode layer 14A. A part of the surface of the polymer material layer 11 is in surface contact with the spacer layer 13A, and the other part is exposed in the space 17 in the opening 16 formed in the spacer layer 13A. The diameter φ of the opening 16 is 150 μm, and the thickness of the spacer layer 13A is 30 μm.
　図５Ａ～図５Ｃは、複数の光散乱体１５を有する光学素子の一例であるマイクロレンズアレイ１００の作製工程図である。図５Ａで、基材２１の上に第１の電極層１２Ａを形成し、第１の電極層１２Ａの上に高分子材料層１１を形成する。第１の電極層１２Ａは、たとえば厚さ１００μｍＩＴＯフィルムである。高分子材料層１１は、ＰＶＣにアジピン酸ジブチル（ＤＢＡ）を混合比率が８０ｗｔ％となるように添加し、ＴＨＦの溶媒に完全に溶解させてゲル溶液とした後、ゲル溶液を第１の電極層１２Ａの上に厚さ５００μｍでキャストしたものである。可塑剤であるＤＢＡはマイナスイオンを帯びやすく、電圧の印加によりポリマーゲルが陽極に引き付けられる。 5A to 5C are manufacturing process diagrams of a microlens array 100 which is an example of an optical element having a plurality of light scatterers 15. FIG. In FIG. 5A, the first electrode layer 12A is formed on the base material 21, and the polymer material layer 11 is formed on the first electrode layer 12A. The first electrode layer 12A is, for example, a 100 μm thick ITO film. The polymer material layer 11 is prepared by adding dibutyl adipate (DBA) to PVC so that the mixing ratio is 80 wt% and completely dissolving in a solvent of THF to form a gel solution, and then the gel solution is used as the first electrode It is cast at a thickness of 500 μm on the layer 12A. DBA, which is a plasticizer, tends to have negative ions, and application of a voltage causes the polymer gel to be attracted to the anode.
　図５Ｂで、高分子材料層１１の上に、複数の開口１６が形成されたスペーサ層１３Ａと、第２の電極層１４Ａを配置する。スペーサ層１３Ａとして、たとえば厚さ３０μｍのポリイミドフィルムを用いる。第２の電極層１４Ａは、厚さ１００μｍのＩＴＯフィルムである。この例では、スペーサ層１３Ａと第２の電極層１４Ａはあらかじめ貼り合わせられて、電極アセンブリ１９Ａが形成されている。電極アセンブリ１９Ａは、図示しない基材の上に支持されていてもよい。 In FIG. 5B, on the polymer material layer 11, the spacer layer 13A in which the plurality of openings 16 are formed, and the second electrode layer 14A are disposed. For example, a polyimide film having a thickness of 30 μm is used as the spacer layer 13A. The second electrode layer 14A is an ITO film having a thickness of 100 μm. In this example, the spacer layer 13A and the second electrode layer 14A are bonded in advance to form an electrode assembly 19A. The electrode assembly 19A may be supported on a substrate (not shown).
　スペーサ層１３Ａでは、直径が１５０μｍの開口１６が、３０×３０のマトリクスに配置されている。開口１６のピッチＰは２００μｍ、隣接する開口１６と開口１６の間隔は５０μｍである。 In the spacer layer 13A, the openings 16 with a diameter of 150 μm are arranged in a 30 × 30 matrix. The pitch P of the openings 16 is 200 μm, and the distance between the adjacent openings 16 and the openings 16 is 50 μm.
　図５Ｃで、基材２１を剥離して、マイクロレンズアレイ１００の薄膜が完成する。その後、第１の電極層１２Ａと第２の電極層１４Ａの間に所望のレベルの電圧を印加することで、開口１６内に光散乱体１５を発生させる。 In FIG. 5C, the substrate 21 is peeled off to complete the thin film of the microlens array 100. Thereafter, a voltage of a desired level is applied between the first electrode layer 12A and the second electrode layer 14A to generate the light scatterer 15 in the opening 16.
　図６は、複数の光散乱体１５を有する光学素子１０に印加する電圧のレベルを変えながら観察した３Ｄ画像である。３Ｄ観測は、キーエンス社製のデジタルマイクロスコープＶＨＸ１０００を用いて行う。 FIG. 6 is a 3D image observed while changing the level of the voltage applied to the optical element 10 having the plurality of light scatterers 15. 3D observation is performed using a digital microscope VHX1000 manufactured by Keyence Corporation.
　図６の（ａ）は印加電圧が６００Ｖのときの画像、図６の（ｂ）は印加電圧が７００Ｖのときの画像、図６の（ｃ）は印加電圧が８００Ｖのときの画像である。電圧の印加により、ポリマーゲルが中心部から引き上げられる様子がわかる。 6A shows an image when the applied voltage is 600V, FIG. 6B shows an image when the applied voltage is 700V, and FIG. 6C shows an image when the applied voltage is 800V. It can be seen that the application of voltage causes the polymer gel to be pulled up from the center.
　図７は、図６の３Ｄ画像から、３つの連続する光散乱体１５の高さを電圧印加の関数としてプロットしたものである。縦軸が初期状態（電圧の印加なしの状態）での高分子材料層１１の表面位置からの高さ、横軸がスペーサ層１３Ａの開口１６の面内位置であり、１グリッドを１５０μｍとしている。 FIG. 7 is a plot of the height of three consecutive light scatterers 15 as a function of voltage application from the 3D image of FIG. The ordinate represents the height from the surface position of the polymer material layer 11 in the initial state (state without application of voltage), the abscissa represents the in-plane position of the opening 16 of the spacer layer 13A, and one grid is 150 μm. .
　電圧の印加がないとき（０Ｖ）、開口１６の内部での高分子材料層１１の高さ位置は、－２０μｍの近傍にある。これは、光学的な測定で光が入りづらい深さ方向での誤差（±２０μｍ程度）の影響であり、開口１６内での高分子材料層１１のプロファイルは平坦になっている。 When no voltage is applied (0 V), the height position of the polymer material layer 11 inside the opening 16 is in the vicinity of −20 μm. This is the effect of an error (about ± 20 μm) in the depth direction where light does not easily enter in optical measurement, and the profile of the polymer material layer 11 in the opening 16 is flat.
　電圧の印加が５００Ｖのとき、ポリマーゲルが大きく変形して、開口１６の中心を中心軸として突起が形成される。電圧レベルが６００Ｖと７００Ｖでは、ピークの高さ位置がさらに増大し、縦に長い凸形状のプロファイルが得られる。このときの光散乱体１５の高さは５０μｍに達する。電圧の印加が８００Ｖのときはピークの高さ位置はやや低減するが、幅も小さくなり、急峻度はより大きくなる。ピーク近傍での曲率半径は、より小さくなる。 When the voltage application is 500 V, the polymer gel is largely deformed to form a protrusion with the center of the opening 16 as a central axis. At voltage levels of 600 V and 700 V, the height position of the peak is further increased, and a vertically long convex profile is obtained. The height of the light scatterer 15 at this time reaches 50 μm. When the voltage application is 800 V, the height position of the peak is slightly reduced, but the width is also reduced and the steepness is further increased. The radius of curvature near the peak is smaller.
　図７のプロファイルから分かるように、光学素子１０（またはマイクロレンズアレイ１００）に印加される電圧レベルを制御することで、所望のレンズ形状の光学素子１０（またはマイクロレンズアレイ１００）が得られる。 As can be seen from the profile of FIG. 7, by controlling the voltage level applied to the optical element 10 (or the microlens array 100), the optical element 10 (or the microlens array 100) having a desired lens shape can be obtained.
　なお８００Ｖを印加してもポリマーゲルに流れる電流は１０μＡ以下と非常に低く、発熱量が抑制され、長期間の使用に耐えられる。 Even when 800 V is applied, the current flowing through the polymer gel is as low as 10 μA or less, the calorific value is suppressed, and it can withstand long-term use.
　図８は、変形例の光学素子１０Ｂの概略図である。上述した実施形態では、平坦な第２の電極層１４Ａに、開口１６を有する絶縁性のスペーサ層１３Ａを張り合わせて用いていた。変形例では、第２の電極層１４Ｂの高分子材料層１１と対向する主面１４１に開口１４３を設け、主面１４１と開口１４３内の側壁を、絶縁性のスペーサ層１３Ｂで覆う。開口１４３の底面１４５はスペーサ層１３Ｂで覆われずに、露出している。 FIG. 8 is a schematic view of an optical element 10B according to a modification. In the embodiment described above, the insulating spacer layer 13A having the opening 16 is used by being bonded to the flat second electrode layer 14A. In the modified example, an opening 143 is provided in the main surface 141 opposite to the polymer material layer 11 of the second electrode layer 14B, and the sidewall in the main surface 141 and the opening 143 is covered with the insulating spacer layer 13B. The bottom surface 145 of the opening 143 is exposed without being covered by the spacer layer 13B.
　開口１４３を有する第２の電極層１４Ｂとスペーサ層１３Ｂは、電極アセンブリ１９Ｂとして一体的に形成されていてもよい。開口１４３は、ウェットエッチングまたはドライエッチングで所望の形状に形成することができる。たとえば、開口１４３の平面形状は、所定の径を有する円、楕円、多角形等である。 The second electrode layer 14B having the opening 143 and the spacer layer 13B may be integrally formed as the electrode assembly 19B. The opening 143 can be formed into a desired shape by wet etching or dry etching. For example, the planar shape of the opening 143 is a circle, an ellipse, a polygon or the like having a predetermined diameter.
　開口１４３が形成された第２の電極層１４Ｂの主面１４１の全面に絶縁性のスペーサ層１３Ｂを形成し、フォトリソグラフィとエッチングにより、開口１４３の底面１４５のスペーサ層１３Ｂを除去して、開口１４３内に第２の電極層１４Ｂを露出する。開口１４３の側壁を覆うスペーサ層１３によって、第２の電極層１４Ｂと高分子材料層１１の間に、所定の空間１７が形成される。 The insulating spacer layer 13B is formed on the entire main surface 141 of the second electrode layer 14B in which the opening 143 is formed, and the spacer layer 13B on the bottom surface 145 of the opening 143 is removed by photolithography and etching. The second electrode layer 14 B is exposed in 143. A predetermined space 17 is formed between the second electrode layer 14 B and the polymer material layer 11 by the spacer layer 13 covering the side wall of the opening 143.
　図８の（ａ）に示すように、電圧を印加しない状態では、空間１７の内部で、高分子材料層１１の表面は平坦になっている。開口１４３以外の領域で、高分子材料層１１はスペーサ層１３Ｂと面接触している。 As shown in (a) of FIG. 8, the surface of the polymer material layer 11 is flat inside the space 17 when no voltage is applied. The polymer material layer 11 is in surface contact with the spacer layer 13 B in the region other than the opening 143.
　図８の（ｂ）に示すように、第１の電極層１２Ｂと第２の電極層１４Ｂの間に電圧が印加されると、高分子材料層１１が変形し、開口１４３の内部で中心部から優先的に第２の電極層１４Ｂに向かって引っ張られる。これにより、空間１７の中に凸形状の光散乱体１５が形成される。 As shown in (b) of FIG. 8, when a voltage is applied between the first electrode layer 12B and the second electrode layer 14B, the polymer material layer 11 is deformed, and the central portion in the opening 143 is formed. Are preferentially pulled toward the second electrode layer 14B. Thus, the light scatterer 15 having a convex shape is formed in the space 17.
　図８の光学素子１０Ｂも、複数の光散乱体１５を形成することで、マイクロレンズアレイとして用いることができる。この場合は、第２の電極層１４Ｂに複数の開口１４３を形成し、全面にスペーサ層１３Ｂを形成した後に、開口１４３の底面を露出すればよい。電圧を印加することで、複数の開口１４３の内部に、均一な形状の光散乱体１５を形成することができる。 The optical element 10B of FIG. 8 can also be used as a microlens array by forming a plurality of light scatterers 15. In this case, after the plurality of openings 143 are formed in the second electrode layer 14B and the spacer layer 13B is formed on the entire surface, the bottom surface of the opening 143 may be exposed. By applying a voltage, it is possible to form the light scatterer 15 having a uniform shape inside the plurality of openings 143.
　図９は、実施形態のマイクロレンズアレイ１００を用いた撮像装置１５０の模式図である。マイクロレンズアレイ１００として、実施形態の光学素子１０Ａと、変形例の光学素子１０Ｂのいずれを用いてもよい。図９の例では、第１の電極層１２、高分子材料層１１、スペーサ層１３、及び第２の電極層１４がこの順で積層された光学素子１０Ａをマイクロレンズアレイ１００として用いている。 FIG. 9 is a schematic view of an imaging device 150 using the microlens array 100 of the embodiment. As the microlens array 100, any of the optical element 10A of the embodiment and the optical element 10B of the modification may be used. In the example of FIG. 9, the optical element 10A in which the first electrode layer 12, the polymer material layer 11, the spacer layer 13, and the second electrode layer 14 are stacked in this order is used as the microlens array 100.
　撮像装置１５０は、複数の光散乱体１５の配列を有するマイクロレンズアレイ１００と、複数の撮像素子が配列された撮像素子アレイ１３０を有する。撮像素子は、ＣＣＤ（charge coupled device）、ＣＭＯＳ（complementary metal oxide semiconductor）センサなどで形成されている。撮像素子の配列に対応して、三色のカラーフィルタ１３１が配置されていてもよい。この例では、赤（Ｒ）、緑（Ｇ）、青（Ｂ）のカラーフィルタ１３１Ｒ、１３１Ｇ、１３１Ｂが交互に配置されている。 The imaging device 150 has a microlens array 100 having an array of a plurality of light scatterers 15, and an imaging element array 130 in which a plurality of imaging elements are arrayed. The imaging device is formed of a charge coupled device (CCD), a complementary metal oxide semiconductor (CMOS) sensor, or the like. Three color filters 131 may be arranged corresponding to the arrangement of the imaging elements. In this example, red (R), green (G) and blue (B) color filters 131R, 131G and 131B are alternately arranged.
　図１０は、実施形態のマイクロレンズアレイ１００を用いた照明装置２５０の模式図である。照明装置２５０は、たとえばＬＥＤランプ等の光源２３０と、光源２３０の出力側の前面に配置されたマイクロレンズアレイ１００を有する。マイクロレンズアレイ１００として、実施形態の光学素子１０Ａと変形例の光学素子１０Ｂのいずれを用いてもよい。図１０の例では、第１の電極層１２、高分子材料層１１、スペーサ層１３、及び第２の電極層１４がこの順で積層された光学素子１０Ａをマイクロレンズアレイ１００として用いる。 FIG. 10 is a schematic view of a lighting device 250 using the microlens array 100 of the embodiment. The lighting device 250 includes a light source 230 such as an LED lamp, and a microlens array 100 disposed on the front side of the light source 230 on the output side. As the microlens array 100, any of the optical element 10A of the embodiment and the optical element 10B of the modification may be used. In the example of FIG. 10, the optical element 10A in which the first electrode layer 12, the polymer material layer 11, the spacer layer 13, and the second electrode layer 14 are stacked in this order is used as the microlens array 100.
　電圧を印加することで、スペーサ層１３によって形成される空間内に、所望の形状の光散乱体１５を形成して、光拡散を制御し、輝度を高く保った状態で拡散光を平行光に変換することができる。 By applying a voltage, a light scatterer 15 having a desired shape is formed in the space formed by the spacer layer 13 to control the light diffusion, and the diffused light becomes parallel light in a state where the luminance is kept high. It can be converted.
　図９及び図１０の適用例以外にも、光学素子１０Ａ、１０Ｂは光学顕微鏡、産業用等の照明装置等に適用することができる。 The optical elements 10A and 10B can be applied to an optical microscope, a lighting device for industrial use, and the like other than the application examples of FIGS. 9 and 10.
　マイクロレンズアレイ１００は、１ｍｍ以下の薄型に形成され、陽極、陰極ともに透明化することができるので、超薄型カメラ、ヘッドマウントディスプレイ（ＨＭＤ）、マイクロレンズアレイ（ＭＬＡ）シート、等への適用のほか、内視鏡システム等の医療の分野にも有効に適用できる。光散乱体１５の数が単一の光学素子１０も、医療、画像形成の分野で光拡散シート、レンズシート等に適用することができる。 The microlens array 100 is formed to be 1 mm or less in thickness, and both the anode and the cathode can be made transparent, so application to an ultra-thin camera, head mounted display (HMD), microlens array (MLA) sheet, etc. In addition to the above, the present invention can be effectively applied to the medical field such as an endoscope system. The optical element 10 in which the number of the light scatterers 15 is single can also be applied to a light diffusion sheet, a lens sheet, and the like in the field of medicine and image formation.
　＜高分子材料の構成＞
　上述のように、実施形態の光学素子１０とマイクロレンズアレイ１００は、複雑な機構を用いずに電圧をオン／オフ制御、あるいは電圧レベルを調整することで、様々な配向分布をもつ光散乱体１５を発生させることができる。ここで、印加される電圧は低い方が望ましい。そこで、光学素子及びマイクロレンズアレイに用いられる高分子材料の組成を工夫して、印加電圧を低減する。 <Configuration of high molecular weight material>
As described above, the optical element 10 and the microlens array 100 according to the embodiment are light scatterers having various orientation distributions by on / off control of the voltage or adjusting the voltage level without using a complicated mechanism. 15 can be generated. Here, it is desirable that the applied voltage be low. Therefore, the applied voltage is reduced by devising the composition of the polymer material used for the optical element and the microlens array.
　具体的には、高分子材料層１１で用いられるゲル状の高分子材料（ポリマーゲル）に、所定の条件を満たすイオン液体を添加することで、光学素子１０またはマイクロレンズアレイ１００の駆動電圧を低減する。イオン液体の添加により、高分子材料の変形効率を高めることができる。 Specifically, the driving voltage of the optical element 10 or the microlens array 100 can be obtained by adding an ionic liquid satisfying a predetermined condition to the gel-like polymer material (polymer gel) used in the polymer material layer 11. Reduce. The addition of the ionic liquid can enhance the deformation efficiency of the polymer material.
　イオン液体は、カチオン（正の電荷を帯びたイオン）とアニオン（負の電荷を帯びたイオン）で構成される塩であり、２５℃で液体のものをいう。所定の条件のひとつは、イオン液体が、２５℃で一定値以上のアニオン（負イオン）輸率をもつことである。この条件の詳細については、後述する。 The ionic liquid is a salt composed of a cation (positively charged ion) and an anion (negatively charged ion), and is a liquid at 25 ° C. One of the predetermined conditions is that the ionic liquid has an anion (negative ion) transport number of a certain value or more at 25 ° C. Details of this condition will be described later.
　高分子材料は、上述したように、ポリ塩化ビニル（ＰＶＣ：polyvinyl chloride）、ポリメタクリル酸メチル、ポリウレタン、ポリスチレン、ポリ酢酸ビニル、ポリビニルアルコール、ポリカーボネート、ポリエチレンテレフタレート、ポリアクリロニトリル、シリコーンゴム等である。好ましい構成例では、使用波長に対して透明な高分子または樹脂材料が用いられる。 The polymer material is, as described above, polyvinyl chloride (PVC), polymethyl methacrylate, polyurethane, polystyrene, polyvinyl acetate, polyvinyl alcohol, polycarbonate, polyethylene terephthalate, polyacrylonitrile, silicone rubber and the like. In a preferred embodiment, a polymer or resin material transparent to the used wavelength is used.
　このような高分子材料に対するイオン液体の重量割合は、０．２ wt%以上、１．５ wt%以下であり、より好ましくは、０．３ wt%以上、１．０ wt%以下である。高分子材料の重量を１（または１００％）としたときに、この重量割合のイオン液体を混合することで、光学素子またはマイクロレンズアレイの駆動電圧を低減することができる。この根拠についても後述する。 The weight ratio of the ionic liquid to such a polymer material is 0.2 wt% or more and 1.5 wt% or less, more preferably 0.3 wt% or more and 1.0 wt% or less. When the weight of the polymer material is 1 (or 100%), the drive voltage of the optical element or the microlens array can be reduced by mixing this weight ratio of the ionic liquid. This basis will also be described later.
　ポリマーゲルに適切な可塑剤を添加してもよいし、溶媒に溶解させてもよい。可塑剤を用いる場合は、アジピン酸ジブチル（ＤＢＡ：dibutyl adipate）、アジピン酸ジエチル（ＤＥＡ：diethyl adipate）、セバシン酸ジエチル（ＤＥＳ：diethyl sebacate）、フタル酸ジオクチル（ＤＯＰ：dioctyl phthalate）、フタル酸ジエチル（ＤＥＰ：diethyl phthalate）等を用いることができる。溶媒としては、テトラヒドロフラン（ＴＨＦ）等のエーテル系の溶媒を用いることができる。 A suitable plasticizer may be added to the polymer gel or it may be dissolved in a solvent. When a plasticizer is used, dibutyl adipate (DBA: dibutyl adipate), diethyl adipate (DEA: diethyl adipate), diethyl sebacate (DES: diethyl sebacate), dioctyl phthalate (DOP: dioctyl phthalate), diethyl phthalate (DEP: diethyl phthalate) etc. can be used. As the solvent, ether solvents such as tetrahydrofuran (THF) can be used.
　イオン液体が添加された高分子材料は、図１及び図２の光学素子１０Ａ、図８の光学素子１０Ｂ、及び図３のマイクロレンズアレイ１００のいずれにも適用可能である。以下で詳細に述べるように、高分子材料に所定の条件のイオン液体を添加することで、高分子材料層１１の駆動電圧を２００Ｖ以下、より好ましくは、１５０Ｖ以下に低減することができる。 The polymer material to which the ionic liquid is added is applicable to any of the optical element 10A of FIGS. 1 and 2, the optical element 10B of FIG. 8, and the microlens array 100 of FIG. As described in detail below, the drive voltage of the polymer material layer 11 can be reduced to 200 V or less, more preferably 150 V or less, by adding an ionic liquid under predetermined conditions to the polymer material.
　図１１は、イオン液体を添加した高分子材料の特性を測定するためのサンプル１１０の模式図である。図１１の（ａ）は電圧の印加がない状態、図１１の（ｂ）は電圧が印加されている状態である。 FIG. 11 is a schematic view of a sample 110 for measuring the characteristics of the polymer material to which the ionic liquid is added. FIG. 11 (a) shows a state in which no voltage is applied, and FIG. 11 (b) shows a state in which a voltage is applied.
　高分子材料の様々な特性を調べるために、電極１１２と電極１１３の間に高分子材料層１１１を挟んだサンプルを作製する。重量平均分子量が２３００００のＰＶＣをテトラヒドロフラン（ＴＨＦ）の溶媒に溶解させたポリマーゲルを準備し、種々のイオン液体を添加して複数種類のサンプルを作製する。比較例として、イオン液体が添加されていないポリマーゲルを用いたときの特性も測定する。 In order to investigate various characteristics of the polymer material, a sample is prepared in which the polymer material layer 111 is sandwiched between the electrode 112 and the electrode 113. A polymer gel in which PVC having a weight average molecular weight of 230,000 is dissolved in a solvent of tetrahydrofuran (THF) is prepared, and various ionic liquids are added to prepare multiple types of samples. As a comparative example, the characteristics when using a polymer gel to which no ionic liquid is added are also measured.
　下部電極となる電極１１２の上に、サンプルと比較例のポリマーゲルを厚さ３００μｍに塗布する。ポリマーゲルの上に、上部の電極１１３として、直径１００μｍのホールが形成された厚さ２０μｍの金属薄膜を配置する。電極１１２と電極１１３の間に印加する電圧を０Ｖから４００Ｖの間で変化させて、電極１１３から突出する光散乱体１１５の頂点（ピーク）の高さｈを測定する。高さｈは、電極１１３の表面１１３ｓからの高さである。電極１１２は陰極、電極１１３を陽極とする。 The polymer gel of the sample and the comparative example is applied to a thickness of 300 μm on the electrode 112 serving as the lower electrode. On the polymer gel, a metal thin film with a thickness of 20 μm in which a hole with a diameter of 100 μm is formed is disposed as the upper electrode 113. The voltage applied between the electrode 112 and the electrode 113 is changed between 0 V and 400 V, and the height h of the peak (peak) of the light scatterer 115 protruding from the electrode 113 is measured. The height h is the height from the surface 113 s of the electrode 113. The electrode 112 is a cathode, and the electrode 113 is an anode.
　実施形態の光学素子１０は、電圧印加によるポリマーゲルの弾性変形を利用して、ポリマーゲルを電極に引き付けて空間内に光散乱体１５を形成しているが、図１１のサンプル１１０も、電圧印加による弾性変形を利用して光散乱体１１５を形成する点では同じである。図１１のサンプルで得られたポリマーゲルの特性測定の結果は、図１～図３、及び図８の構成に当てはめることができる。 The optical element 10 of the embodiment attracts the polymer gel to the electrode to form the light scatterer 15 in the space using elastic deformation of the polymer gel by voltage application, but the sample 110 in FIG. The same applies in that the light scatterer 115 is formed utilizing elastic deformation by application. The results of the property measurement of the polymer gel obtained for the sample of FIG. 11 can be applied to the configurations of FIGS. 1 to 3 and FIG.
　図１２は、種々のイオン液体を添加したときのポリマーゲルの電圧応答特性を示す。高分子材料層１１１に印加される電圧値を変えて、ピーク高さｈの電圧依存性を測定する。比較例として、イオン液体が添加されていないポリマーゲルを用いて、同じくピーク高さの電圧依存性を測定する。 FIG. 12 shows the voltage response characteristics of the polymer gel when various ionic liquids are added. The voltage dependency of the peak height h is measured by changing the voltage value applied to the polymer material layer 111. As a comparative example, the voltage dependence of peak height is also measured using a polymer gel to which no ionic liquid is added.
　ラインＡは、イオン液体として１－エチル－３－メチルイミダゾリウム＝テトラフルオロボラート（ＥＭＩ-ＢＦ4）を添加したサンプルＡのピーク高さの電圧依存性を示す。ＰＶＣに対するＥＭＩ－ＢＦ4の重量割合は０．５ wt%である。ＥＭＩはカチオン、ＢＦ4はアニオンである。 Line A shows the voltage dependence of the peak height of sample A to which 1-ethyl-3-methylimidazolium = tetrafluoroborate (EMI-BF 4 ) is added as an ionic liquid. The weight ratio of EMI-BF 4 to PVC is 0.5 wt%. EMI is a cation and BF 4 is an anion.
　ラインＢは、イオン液体として１－オクチル－３－メチルイミダゾリウム＝テトラフルオロボラート（ＯＭＩ-ＢＦ4）を添加したサンプルＢのピーク高さの電圧依存性を示す。ＰＶＣに対するＯＭＩ－ＢＦ4の重量割合は０．５ wt%である。ＯＭＩはカチオン、ＢＦ4はアニオンである。 Line B shows the voltage dependence of the peak height of sample B to which 1-octyl-3-methylimidazolium = tetrafluoroborate (OMI-BF 4 ) is added as an ionic liquid. The weight ratio of OMI-BF 4 to PVC is 0.5 wt%. OMI is a cation and BF 4 is an anion.
　ラインＣは、イオン液体として１－エチル－３－メチルイミダゾリウム＝ジシアナミド（ＥＭＩ-ＤＣＡ）を添加したサンプルＣのピーク高さの電圧依存性を示す。ＰＶＣに対するＥＭＩ－ＤＣＡの重量割合は、０．５ wt%である。ＥＭＩはカチオン、ＤＣＡ（Ｃ2Ｎ3）はアニオンである。 Line C shows the voltage dependence of the peak height of sample C to which 1-ethyl-3-methylimidazolium dicyanamide (EMI-DCA) is added as an ionic liquid. The weight ratio of EMI-DCA to PVC is 0.5 wt%. EMI is a cation, and DCA (C 2 N 3 ) is an anion.
　ラインＤは、イオン液体としてテトラブチルホスホニウム=テトラフルオロボラート（ＴＢＰ－ＢＦ4）を添加したサンプルＤのピーク高さの電圧依存性を示す。ＰＶＣに対するＴＢＰ－ＢＦ4の重量割合は、０．１ wt%である。ＴＢＰはカチオン、ＢＦ4はアニオンである。 The line D shows the voltage dependence of the peak height of the sample D to which tetrabutylphosphonium = tetrafluoroborate (TBP-BF 4 ) is added as the ionic liquid. The weight ratio of TBP-BF 4 to PVC is 0.1 wt%. TBP is a cation, and BF 4 is an anion.
　ラインＥは、イオン液体としてテトラブチルホスホニウム=テトラフルオロボラート（ＴＢＰ－ＢＦ4）を添加したサンプルＥのピーク高さの電圧依存性を示す。イオン液体の種類はサンプルＤと同じであるが、ＰＶＣに対するＴＢＰ－ＢＦ4の重量割合は０．５ wt%である。ＴＢＰはカチオン、ＢＦ4はアニオンである。 The line E shows the voltage dependence of the peak height of the sample E to which tetrabutylphosphonium = tetrafluoroborate (TBP-BF 4 ) is added as the ionic liquid. Type of ionic liquids are the same as sample D, but the weight ratio of TBP-BF 4 for PVC is 0.5 wt%. TBP is a cation, and BF 4 is an anion.
　ラインＦは、イオン液体として１－エチル－３－メチルイミダゾリウム＝トリフルオロメタンスルフォンイミド（ＥＭＩ－ＴＦＳＩ）を添加したサンプルＦのピーク高さの電圧依存性を示す。ＰＶＣに対するＥＭＩ－ＴＦＳＩの重量割合は０．５ wt%である。ＥＭＩはカチオン、ＴＦＳＩはアニオンである。 Line F shows the voltage dependence of the peak height of sample F to which 1-ethyl-3-methylimidazolium = trifluoromethanesulfonimide (EMI-TFSI) is added as an ionic liquid. The weight ratio of EMI-TFSI to PVC is 0.5 wt%. EMI is a cation and TFSI is an anion.
　ラインＧは、イオン液体としてテトラブチルホスホニウム＝メタンスルホン酸（ＴＢＰ－ＭＥＳ）を添加したサンプルＧのピーク高さの電圧依存性を示す。ＰＶＣに対するＴＢＰ－ＭＥＳの重量割合は、０．５ wt%である。ＴＢＰはカチオン、ＭＥＳはアニオンである。 Line G shows the voltage dependency of the peak height of sample G to which tetrabutylphosphonium = methanesulfonic acid (TBP-MES) is added as an ionic liquid. The weight ratio of TBP-MES to PVC is 0.5 wt%. TBP is a cation and MES is an anion.
　ラインＷは、比較例としてイオン液体が添加されていないサンプルＷのＰＶＣポリマーゲルのピーク高さの電圧依存性を示す。 Line W shows the voltage dependence of the peak height of the PVC polymer gel of sample W to which the ionic liquid is not added as a comparative example.
　図１２の測定結果から、イオン液体を添加しない場合でも、誘電分極が生じるポリマーゲルを用いることで、電圧印加によりポリマーゲルが変形する。イオン液体を添加していない比較例のポリマーゲルＷでは、印加電圧に対してほぼリニアに光散乱体１１５の高さが増大している。しかし、サンプルＷを電極１１３の表面１３ｓから２０μｍの高さに突出させるには、４００Ｖの電圧が必要である。 From the measurement results of FIG. 12, even when the ionic liquid is not added, the polymer gel is deformed by the voltage application by using the polymer gel in which dielectric polarization occurs. In the polymer gel W of the comparative example in which the ionic liquid is not added, the height of the light scatterer 115 increases substantially linearly with the applied voltage. However, in order to cause the sample W to project from the surface 13s of the electrode 113 to a height of 20 μm, a voltage of 400 V is required.
　これに対し、イオン液体としてＥＭＩ－ＢＦ4を０．５ wt%添加したサンプルＡと、ＯＭＩ－ＢＦ4を０．５ wt%添加したサンプルＢは、１００Ｖ以下の電圧印加で、高分子材料層１１を２０μｍ以上の高さに駆動することができる。特に、サンプルＡは、５０Ｖの電圧印加で２０μｍの高さ、２００Ｖの電圧印加で、４０μｍ弱の高さに変位する。サンプルＢも、１００Ｖの電圧印加で２５μｍの高さ、２００Ｖの電圧印加で３０μｍの高さに変位する。 On the other hand, Sample A to which 0.5 wt% of EMI-BF 4 was added as an ionic liquid and Sample B to which 0.5 wt% of OMI-BF 4 was added were polymer material layers when a voltage of 100 V or less was applied. 11 can be driven to a height of 20 μm or more. In particular, the sample A is displaced to a height of less than 40 μm by application of a voltage of 50 V and a height of 20 μm and application of a voltage of 200 V. The sample B is also displaced to a height of 25 μm at a voltage application of 100 V and a height of 30 μm at a voltage application of 200 V.
　ＥＭＩ－ＤＣＡを０．５ wt%添加したサンプルＣは、イオン液体を添加しないサンプルＷと比較して、約半分の印加電圧（２１０～２２０Ｖ）で同じ２０μｍのピーク高さを得ることができ、変形効率を大きく向上している。 Sample C added with 0.5 wt% of EMI-DCA can obtain the same 20 μm peak height with about half applied voltage (210 to 220 V) as compared with sample W to which no ionic liquid is added. The deformation efficiency has been greatly improved.
　ＴＢＰ－ＢＦ4を０．１ wt%添加したサンプルＤは、５０Ｖの電圧印加で電極１１３の表面１１３ｓから光散乱体１１５を突出させることができるが、電圧を高くしても、ピーク高さは１０μｍ未満のままであり、５０Ｖから４００Ｖの範囲でピーク高さの変化が小さい。サンプルＤでは、電圧制御により光散乱体１１５の高さを精度良く調整することが難しい。 Sample D, to which 0.1 wt% of TBP-BF 4 is added, can cause the light scatterer 115 to project from the surface 113 s of the electrode 113 by applying a voltage of 50 V, but the peak height is It remains less than 10 μm and the change in peak height is small in the range of 50V to 400V. In the sample D, it is difficult to accurately adjust the height of the light scatterer 115 by voltage control.
　ＴＢＰ－ＢＦ4を０．５ wt%添加したサンプルＥ、ＥＭＩ－ＴＦＳＩを０．５ wt%添加したサンプルＦ、及びＴＢＰ－ＭＥＳを０．５ wt%添加したサンプルＧは、４００Ｖの電圧を印加しても、電極１１３の表面１１３ｓから光散乱体１１５を突出させることができない。 Sample E with 0.5 wt% TBP-BF 4 added, Sample F with 0.5 wt% EMI-TFSI added, and Sample G with 0.5 wt% TBP-MES applied a voltage of 400 V However, the light scatterer 115 can not protrude from the surface 113 s of the electrode 113.
　図１２の測定結果から、イオン液体の種類（すなわち物性）と添加量の少なくとも一方が高分子材料層１１１の駆動電圧の低減に関与していると考えられる。 From the measurement results of FIG. 12, it is considered that at least one of the type (ie, physical properties) and the addition amount of the ionic liquid is involved in the reduction of the drive voltage of the polymer material layer 111.
　＜ポリマーゲルの変位とイオン液体の物性の関係＞
　図１３は、ポリマーゲルの変位とイオン液体の物性の関係を示す図である。イオン液体として、図１２のサンプルＡ～Ｇに加えて、１－エチル－３－メチルイミダゾリウム＝フルオロスルホニルイミド（ＥＭＩ－ＦＳＩ）を添加したサンプルＨの物性も併せて測定する。 <Relationship between displacement of polymer gel and physical properties of ionic liquid>
FIG. 13 is a view showing the relationship between the displacement of the polymer gel and the physical properties of the ionic liquid. The physical properties of Sample H to which 1-ethyl-3-methylimidazolium = fluorosulfonylimide (EMI-FSI) is added as an ionic liquid in addition to Samples A to G in FIG. 12 are also measured.
　各種のイオン液体を添加したサンプルＡ～Ｈで、変位がプラスのものは、電圧の印加によりポリマーゲルが電極１１３の表面１１３ｓから突出して光散乱体１１５が形成されたものを示す。変位がマイナスのものは、電圧を印加しても電極１１３の表面１１３ｓからポリマーゲルが突出しないものである。 The samples A to H to which various ionic liquids are added, in which the displacement is positive, indicate that the polymer gel protrudes from the surface 113 s of the electrode 113 by application of a voltage and the light scatterer 115 is formed. The negative displacement is one in which the polymer gel does not protrude from the surface 113s of the electrode 113 even when a voltage is applied.
　各イオン液体の物性として、導電率、電位窓のサイズ、２５℃での負イオンの拡散係数と輸率を測定する。用いたイオン液体の中には、２５℃で固体のものもあるため、８０℃に加熱して溶融したものについては、８０℃での負イオンの拡散係数と輸率を測定する。 As physical properties of each ionic liquid, conductivity, size of potential window, diffusion coefficient and transport number of negative ions at 25 ° C. are measured. Since some of the used ionic liquids are solid at 25 ° C., the diffusion coefficient and transport number of negative ions at 80 ° C. are measured for those melted by heating to 80 ° C.
　上述のパラメータのうち、まず導電率について検討する。サンプルＣは、サンプルＡ，Ｂと比較して導電率が２桁小さいが、サンプルＣを添加したポリマーゲルはプラスに変位している。これに対し、サンプルＨは、サンプルＣよりもはるかに導電率が大きいが、ポリマーゲルはプラスに変位していない。イオン液体の導電率は、ポリマーゲルの変形効率に直接関係しないと考えられる。 Among the above-mentioned parameters, the conductivity will be examined first. Although the conductivity of sample C is smaller by two orders of magnitude compared with samples A and B, the polymer gel to which sample C is added is positively displaced. In contrast, sample H is much more conductive than sample C, but the polymer gel is not positively displaced. It is believed that the conductivity of the ionic liquid is not directly related to the deformation efficiency of the polymer gel.
　電位窓は、図１１の系で電気化学的に安定性が保たれる電位領域のことである。電位窓が広いほど（数値が大きいほど）、系が電気化学的に安定する範囲が広い。サンプルＡとサンプルＦの電位窓は同じ広さであるにもかかわらず、サンプルＡのポリマーゲルはプラスに変位し、サンプルＦのポリマーゲルは、プラスの変位が得られていない。イオン液体の電位窓の広さも、ポリマーゲルの変形効率に直接関係しないと考えられる。 The potential window is a potential region where the electrochemical stability is maintained in the system of FIG. The wider the voltage window (the larger the value), the wider the range in which the system is electrochemically stable. Although the potential windows of the sample A and the sample F are the same width, the polymer gel of the sample A is displaced to the plus, and the polymer gel of the sample F does not obtain the plus displacement. The width of the potential window of the ionic liquid is also considered not to be directly related to the deformation efficiency of the polymer gel.
　次に、２５℃でのアニオン（負イオン）の拡散係数と輸率について検討する。イオン液体に含まれる正負イオンの拡散係数は、測定機器として、固体ＮＭＲ（Varian社製のVNMR System）を用いて測定する。測定手順は、キャピラリーにイオン液体を注入し、装置にセットする。所定温度（この場合は２５℃と８０℃）で磁場の変化に対するシグナル強度を計測し、Stokes-Einsteinの式から正負イオンの拡散係数を算出する。 Next, the diffusion coefficient and transport number of anions (negative ions) at 25 ° C. are examined. The diffusion coefficient of positive and negative ions contained in the ionic liquid is measured using solid-state NMR (VNMR System manufactured by Varian) as a measurement instrument. In the measurement procedure, an ionic liquid is injected into the capillary and set in the apparatus. The signal intensity with respect to the change of the magnetic field is measured at a predetermined temperature (in this case, 25 ° C. and 80 ° C.), and the diffusion coefficients of positive and negative ions are calculated from the Stokes-Einstein equation.
　負イオンの輸率は、イオン液体に電流を流した際に、全電流に対するアニオンが担う電流の割合を表わす。負イオンの輸率は、上記で求めた負イオンの拡散係数と正イオンの拡散係数の総和に対する負イオンの拡散係数の比（Ｄanion／（Ｄcation＋Ｄanion））として計算される。 The transport number of negative ions represents the ratio of the current carried by the anion to the total current when a current is applied to the ionic liquid. The transport number of the negative ion is calculated as the ratio of the diffusion coefficient of the negative ion to the sum of the diffusion coefficient of the negative ion and the diffusion coefficient of the positive ion determined above (D anion / (D cation + D anion )).
　サンプルＡ、Ｂ、Ｃ、Ｆ、Ｈに用いられたイオン液体は、２５℃で液体であり、液体クロマトグラフィーによる測定結果から、各イオン液体の負イオンの拡散係数と輸率を算出した。プラスの変位が得られたサンプルＡ、Ｂ，Ｃで、２５℃でのイオン液体の負イオンの輸率は、いずれも０．４以上である。これに対し、プラスの変位が得られないサンプルＦとＨで用いられたイオン液体の２５℃での負イオンの輸率は０．４よりも小さい。ここから、室温での負イオンの輸率がポリマーゲルの変形効率に影響していると考えられる。 The ionic liquids used for the samples A, B, C, F, and H were liquids at 25 ° C., and the diffusion coefficient and transport number of negative ions of each ionic liquid were calculated from the measurement results by liquid chromatography. In samples A, B, and C where positive displacements were obtained, the transport number of negative ions of the ionic liquid at 25 ° C. is 0.4 or more. On the other hand, the transport number of negative ions at 25 ° C. of the ionic liquid used in samples F and H which can not obtain positive displacement is smaller than 0.4. From this, it is considered that the transport number of negative ions at room temperature influences the deformation efficiency of the polymer gel.
　なお、プラスの変位が得られたサンプルＤに添加されたイオン液体ＴＢＰ－ＢＦ4は、用いた液体クロマトグラフの加熱可能温度（８０℃）では溶融しないため、拡散係数を測定することができなかった。 In addition, since the ionic liquid TBP-BF 4 added to the sample D from which positive displacement was obtained is not melted at the heatable temperature (80 ° C.) of the liquid chromatograph used, the diffusion coefficient can not be measured. The
　プラスの変位が得られないサンプルＧに添加されたイオン液体ＴＢＰ－ＭＥＳも２５℃で固体であるため、拡散係数を測定することができない。このイオン液体を８０℃に加熱したところ、溶融したので負イオンの拡散係数と輸率を計算したところ、輸率は０．６であった。 Since the ionic liquid TBP-MES added to the sample G which can not obtain positive displacement is also solid at 25 ° C., the diffusion coefficient can not be measured. When this ionic liquid was heated to 80 ° C. and melted, the diffusion coefficient and transport number of negative ions were calculated, and the transport number was 0.6.
　図１３の結果から、高分子材料層１１に添加されるイオン液体の特性として、２５℃での負イオンの輸率が０．４以上のものが望ましいとわかる。 From the results of FIG. 13, it is understood that, as a characteristic of the ionic liquid to be added to the polymer material layer 11, one having a transport number of negative ions of at least 0.4 at 25 ° C. is desirable.
　図１２及び図１３から、イオン液体のアニオンのサイズ（分子量）が小さいほうが、ポリマーゲルの変形効率に寄与することが推定される。一方、イオン液体のカチオンのサイズは、変形効率にはそれほど寄与していないと考えられる。しかし、サンプルＤの変形効率が十分でないことから、カチオンの種類によって、陰極の劣化に影響している可能性がある。これについては、図１６を参照して後述する。 From FIGS. 12 and 13, it is estimated that the smaller the size (molecular weight) of the anion of the ionic liquid, the more it contributes to the deformation efficiency of the polymer gel. On the other hand, it is considered that the size of the cation of the ionic liquid does not contribute so much to the deformation efficiency. However, since the deformation efficiency of the sample D is not sufficient, the type of cation may affect the deterioration of the cathode. This will be described later with reference to FIG.
　なお、サンプルＧで用いられたイオン液体のアニオンサイズもカチオンサイズも中程度であるが、イオン液体が２５℃で固体であるため、攪拌によってポリマーゲル中に分散されても、ゲルの変形効率にはそれほど寄与していないものと考えられる。 Although the anion size and the cation size of the ionic liquid used in sample G are also moderate, the ionic liquid is solid at 25 ° C. Therefore, even if the ionic liquid is dispersed in the polymer gel by stirring, the deformation efficiency of the gel is Is considered to have contributed less.
　以上から、ＢＦ4 ―及びＤＣＡ以外にも、アニオンとしてイオンサイズが比較的小さいＣｌ－やＢｒ―を用いることができる。また、カチオンとして、陰極の劣化に影響しないものを選択することで、種々のイオン液体を用いることができる。たとえば、Ｌｉ－ＢＦ4 ―をイオン液体として用い得る。 From the above, other than BF 4 − and DCA, Cl − or Br − having a relatively small ion size can be used as an anion. Moreover, various ionic liquids can be used by selecting the thing which does not influence deterioration of a cathode as a cation. For example, Li-BF 4 - may be used as ionic liquids.
　＜イオン液体の添加量とポリマーゲルの変位の関係＞
　図１４は、イオン液体の添加量とポリマーゲルの変位の関係を示す図である。横軸は、ポリマーゲルの高分子材料に対するイオン液体の含有量（wt%）、縦軸が変位のピーク高さである。 <Relationship between the amount of ionic liquid added and displacement of polymer gel>
FIG. 14 is a graph showing the relationship between the amount of ionic liquid added and the displacement of the polymer gel. The abscissa represents the content (wt%) of the ionic liquid relative to the polymer material of the polymer gel, and the ordinate represents the peak height of the displacement.
　高分子材料として、分子量が２３００００のＰＶＣを用い、イオン液体としてサンプルＡのＥＭＩ－ＢＦ4を用いる。ＥＭＩ－ＢＦ4の添加量を０ wt%から５．０ wt%の範囲で変化させる。また、印加電圧を０Ｖ、５０Ｖ、１００Ｖ、２００Ｖ、４００Ｖと変える。 As the polymer material, PVC having a molecular weight of 230,000 is used, and EMI-BF 4 of sample A is used as the ionic liquid. The amount of EMI-BF 4 added is varied in the range of 0 wt% to 5.0 wt%. Further, the applied voltage is changed to 0V, 50V, 100V, 200V, and 400V.
　印加する電圧のレベルに拠らず、イオン液体の添加量が、０．２ wt%～１．５ wt%の範囲でプラスの変位が得られる。また、０．３ wt%～１．０ wt%の範囲で、変位が最大になる。この範囲のイオン液体の添加により、１００Ｖ以下の電圧印加で、電極１１３の表面１１３ｓに光散乱体１１５を形成することができる。イオン液体の添加量が５．０ wt%のときは、電圧をオフにしても変形が戻らないメモリー現象が発生する。 Regardless of the level of applied voltage, positive displacement can be obtained when the amount of ionic liquid added is in the range of 0.2 wt% to 1.5 wt%. In addition, the displacement is maximized in the range of 0.3 wt% to 1.0 wt%. By the addition of the ionic liquid in this range, the light scatterer 115 can be formed on the surface 113 s of the electrode 113 by applying a voltage of 100 V or less. When the addition amount of the ionic liquid is 5.0 wt%, a memory phenomenon occurs in which the deformation does not return even when the voltage is turned off.
　図１４から、高分子に対するイオン液体の重量比率は、０．２ wt%～１．５ wt%が望ましく、より好ましくは、０．３ wt%～１．０ wt%であることがわかる。これは、図１２の結果とも一致する。 It can be seen from FIG. 14 that the weight ratio of the ionic liquid to the polymer is preferably 0.2 wt% to 1.5 wt%, more preferably 0.3 wt% to 1.0 wt%. This is also in agreement with the result of FIG.
　図１５は、高分子材料層１１１への電圧印加により形成される光散乱体１１５の光拡散分布の評価結果を、イオン液体の添加量ごとに示す図である。イオン液体としてＥＭＩ－ＢＦ4を用い、ＥＭＩ－ＢＦ4の添加量を変えた高分子材料層１１１で、図１１のサンプル１１０を作製する。高分子材料層１１１は、ポリマーゲルとしてＰＶＣを含み、可塑剤としてアジピン酸ジブチル（ＤＢＡ）を含む。ＰＶＣとＤＢＡの総量に対するＤＢＡの含有割合は８３ wt%である。 FIG. 15 is a view showing the evaluation results of the light diffusion distribution of the light scatterer 115 formed by applying a voltage to the polymer material layer 111 for each addition amount of the ionic liquid. The sample 110 of FIG. 11 is manufactured using the polymer material layer 111 in which EMI-BF 4 is used as the ionic liquid and the addition amount of EMI-BF 4 is changed. The polymer material layer 111 contains PVC as a polymer gel and dibutyl adipate (DBA) as a plasticizer. The content ratio of DBA to the total amount of PVC and DBA is 83 wt%.
　陰極となる電極１１２を、厚さ１５０μｍのＩＴＯで形成し、電極１１２と電極１１３の間に挟んだ高分子材料層１１１に電圧を印加して光散乱体１１５を形成する。ＩＴＯで形成される電極１１２の側にレーザを配置し、光散乱体１１５が形成される側にスクリーンを配置する。電極１１２の裏面側から、赤色平行光のレーザ光をサンプル１１０に入射して、スクリーンでの光拡散状態を観察する。 An electrode 112 to be a cathode is formed of ITO with a thickness of 150 μm, and a voltage is applied to the polymer material layer 111 sandwiched between the electrode 112 and the electrode 113 to form a light scatterer 115. The laser is disposed on the side of the electrode 112 formed of ITO, and the screen is disposed on the side on which the light scatterer 115 is formed. Laser light of red parallel light is incident on the sample 110 from the back surface side of the electrode 112, and the light diffusion state on the screen is observed.
　スクリーンは、光散乱体１１５の光出射側で、光散乱体１１５の焦点よりも遠い位置に配置されている。光散乱体１１５の焦点で一度集光された後の光拡散を、スクリーン上で観察する。サンプル１１０の光散乱体１１５の径は１００μｍ、高さは０～４０μｍ程度と小さく、その焦点位置は光散乱体１１５のきわめて近傍にあり、肉眼での観察が困難だからである。光散乱体１１５の焦点を超えた位置での光拡散を観察することで、集光状態を評価することができる。 The screen is disposed on the light exit side of the light scatterer 115 at a position farther than the focal point of the light scatterer 115. The light diffusion once focused at the focal point of the light scatterer 115 is observed on the screen. The diameter of the light scatterer 115 of the sample 110 is as small as 100 μm and the height is as small as about 0 to 40 μm, and the focal position thereof is very close to the light scatterer 115 and observation with the naked eye is difficult. By observing light diffusion at a position beyond the focus of the light scatterer 115, it is possible to evaluate the light collection state.
　イオン液体が添加されていないサンプル（「w/o IL」と表記）では、２００Ｖの電圧を印加しても電極１１３の表面から突出する光散乱体１１５が形成されない。サンプル１１０の裏面から入射された赤色平行光は、集光されずに平行光のままサンプル１１０を透過する。０Ｖ～４００Ｖの範囲では、印加電圧のレベルにかかわらず、スクリーン上に同じサイズのスポットが形成されている。 In the sample to which the ionic liquid is not added (denoted as “w / o IL”), the light scatterer 115 protruding from the surface of the electrode 113 is not formed even when a voltage of 200 V is applied. The red collimated light incident from the back surface of the sample 110 passes through the sample 110 as collimated light without being collected. In the range of 0 V to 400 V, spots of the same size are formed on the screen regardless of the level of applied voltage.
　ＥＭＩ－ＢＦ4が０．０５ wt%添加されたサンプルでは、１００Ｖの電圧印加により、電極１１３の表面でポリマーゲルがわずかに膨らむが、集光機能が不十分であり、スクリーン位置でほぼ平行光のスポットが維持されている。２００Ｖの電圧印加で、ピーク高さが１０μｍ程度の（曲率の緩やかな）光散乱体１１５が形成される。いったん光散乱体１１５の焦点位置で集光された光は、拡散して広がり、スクリーン上にスポットは現れない。 In the sample to which 0.05 wt% of EMI-BF 4 is added, the application of a voltage of 100 V causes a slight swelling of the polymer gel on the surface of the electrode 113, but the light collecting function is insufficient and almost parallel light at the screen position The spot of is maintained. By applying a voltage of 200 V, a light scatterer 115 (having a gentle curvature) having a peak height of about 10 μm is formed. The light once collected at the focal position of the light scatterer 115 diffuses and spreads, and no spot appears on the screen.
　ＥＭＩ－ＢＦ4が０．５ wt%添加されたサンプルでは、５０Ｖの電圧印加により、電極１１３の表面に光散乱体１１５が形成され、集光後に拡散し始めた光がスクリーン位置で観察される。１００Ｖの電圧と２００Ｖの電圧印加では、５０Ｖ印加時よりもピーク高さが大きい、すなわち曲率が急な光散乱体１１５が電極１１３の表面に形成される。サンプル１１０の裏側から入射した光は、集光された後に大きく拡散し、スクリーン位置でスポットは観察されない。これらの評価結果は、図１４の測定結果と一致する。 In the sample to which 0.5 wt% of EMI-BF 4 is added, a light scatterer 115 is formed on the surface of the electrode 113 by applying a voltage of 50 V, and light which has started to be diffused after being collected is observed at the screen position . At the voltage of 100 V and the voltage application of 200 V, the light scatterer 115 having a peak height larger than that at the time of 50 V application, ie, a sharp curvature, is formed on the surface of the electrode 113. The light incident from the back side of the sample 110 is greatly diffused after being collected, and no spot is observed at the screen position. These evaluation results agree with the measurement results of FIG.
　図１５の光拡散分布から、印加電圧を調整することにより、光散乱体１１５の焦点距離を可変にできることが確認される。この測定結果を実施形態の光学素子１０Ａ，１０Ｂ及びマイクロレンズアレイ１００に適用すると、より低い電圧で光散乱体１１５を形成することができ、変形効率が良好な可変焦点レンズ、または可変形状レンズとして用いることができる。 From the light diffusion distribution of FIG. 15, it is confirmed that the focal length of the light scatterer 115 can be made variable by adjusting the applied voltage. When the measurement results are applied to the optical elements 10A and 10B and the microlens array 100 according to the embodiment, the light scatterer 115 can be formed with a lower voltage, and as a variable focus lens or a variable shape lens with good deformation efficiency. It can be used.
　＜イオン液体（カチオン）の陰極劣化への影響＞
　図１６は、イオン液体の陰極劣化への影響を示す図である。試験用のサンプルとして、金属基板上に、種々のイオン液体を添加したＰＶＣゲルを塗布し、ＰＶＣゲルの上に対向電極としてＩＴＯ電極を配置する。 <Effect of ionic liquid (cation) on cathode deterioration>
FIG. 16 is a view showing the influence of the ionic liquid on the cathode degradation. As a test sample, a PVC gel to which various ionic liquids are added is applied on a metal substrate, and an ITO electrode is disposed on the PVC gel as a counter electrode.
　塗布するＰＶＣゲルの種類は、サンプルＡ（０．５ wt%のＥＭＩ－ＢＦ4を含む）、サンプルＢ（０．５ wt%のＯＭＩ－ＢＦ4を含む）、サンプルＣ（０．５ wt%のＥＭＩ－ＤＣＡを含む）、サンプルＤ（０．１ wt%のＴＢＰ－ＢＦ4を含む）、サンプルＨ（０．５ wt%のＥＭＩ－ＦＳＩを含む）、及びサンプルＧ（０．５ wt%のＴＢＰ－ＭＥＳを含む）の６種類である。このうち、図１３でプラスの変位が得られたのは、サンプルＡ～Ｄである。サンプルＤは、イオン液体の重量割合を他のサンプルと同じ０．５wt%にした場合、変位が得られないので、添加量を０．１ wt%に減らしたサンプルである。 The types of PVC gel to be applied are Sample A (containing 0.5 wt% EMI-BF 4 ), Sample B (containing 0.5 wt% OMI-BF 4 ), Sample C (0.5 wt% EMI-DCA), Sample D (with 0.1 wt% TBP-BF 4 ), Sample H (with 0.5 wt% EMI-FSI), and Sample G (0.5 wt%) (Including TBP-MES). Among these, the samples A to D have obtained positive displacement in FIG. Sample D is a sample in which the added amount is reduced to 0.1 wt% because displacement is not obtained when the weight ratio of the ionic liquid is set to 0.5 wt% the same as the other samples.
　金属基板を正極、ＩＴＯを負極として、ＰＶＣゲルに印加する電圧レベルを変えながらＩＴＯ側から電極の表面状態を観察する。 The surface condition of the electrode is observed from the ITO side while changing the voltage level applied to the PVC gel by using a metal substrate as a positive electrode and ITO as a negative electrode.
　変位効果がなかったサンプルＧは、５０Ｖという低い印加電圧でＩＴＯ（陰極）の劣化が観察される。また、サンプルＤでも電圧印加によるＩＴＯ電極の劣化が観察される。これは、カチオンがＩＴＯ電極の劣化に影響しているためと考えられる。これに対し、変位効果の高いサンプルＡ～Ｃでは、印加電圧を上げてもＩＴＯ電極の劣化は観察されていない。 In the sample G which did not have the displacement effect, deterioration of the ITO (cathode) was observed at a low applied voltage of 50 V. Also in the sample D, deterioration of the ITO electrode due to voltage application is observed. It is considered that this is because the cation affects the deterioration of the ITO electrode. On the other hand, in the samples A to C having a high displacement effect, deterioration of the ITO electrode was not observed even if the applied voltage was increased.
　図１１～図１６の考察から、２５℃で負イオンの輸率が０．４以上のイオン液体を添加することで、イオン液体を添加しないポリマーゲルと比較して、低い印加電圧で大きな変形を得ることができる。特に、サンプルＡとサンプルＢのように、アニオンサイズが小さいイオン液体を用いると、１００Ｖ以下の電圧範囲で、ピーク高さを大きく変えることができ、実施形態の光学素子１０において光散乱体１５の制御が容易である。すなわち、印加電圧のレベルに応じて、空間１７内に光散乱体１５を出現させ、その高さを調整することができる。これらのサンプルを用いる場合は、光学素子１０Ａ，１０Ｂの駆動時に、陰極に対する悪影響も少ない。 From the consideration of FIGS. 11 to 16, by adding an ionic liquid having a transport number of negative ions of 0.4 or more at 25 ° C., large deformation is obtained at a low applied voltage as compared with a polymer gel to which no ionic liquid is added. You can get it. In particular, when an ionic liquid having a small anion size is used as in sample A and sample B, the peak height can be largely changed in the voltage range of 100 V or less. It is easy to control. That is, the light scatterer 15 can be made to appear in the space 17 and its height can be adjusted according to the level of the applied voltage. In the case of using these samples, when the optical elements 10A and 10B are driven, the negative effect on the cathode is also small.
　イオン液体を添加した高分子材料は、上述のように、図３のマイクロレンズアレイ１００に適用可能である。この場合、電極１２Ａと電極１４Ａの間に２００Ｖ以下の電圧を印加することで、空間１７内に光散乱体１５の配列を形成することができる。添加するイオン液体の種類によっては、１００Ｖ以下の電圧印加で２０μｍ以上の高さの光散乱体１５の配列を形成することができる。 The polymeric material to which the ionic liquid is added is applicable to the microlens array 100 of FIG. 3 as described above. In this case, an array of light scatterers 15 can be formed in the space 17 by applying a voltage of 200 V or less between the electrodes 12A and 14A. Depending on the type of ionic liquid to be added, an array of light scatterers 15 having a height of 20 μm or more can be formed by applying a voltage of 100 V or less.
　以上、特定の実施例に基づいて本発明を説明したが、本発明は上述した構成例に限定されない。光学素子１０に複数の光散乱体１５を形成する場合に、光散乱体１５の配列はマトリクス状の配列に限定されず、互い違いに配列してもよい。あるいは、スペーサ層１３Ａの開口１６（または１４３）の形状を六角形にして細密配置にしてもよい。 Although the present invention has been described above based on the specific embodiments, the present invention is not limited to the above-described configuration examples. In the case of forming a plurality of light scatterers 15 in the optical element 10, the arrangement of the light scatterers 15 is not limited to the matrix arrangement, and may be alternately arranged. Alternatively, the shape of the openings 16 (or 143) of the spacer layer 13A may be hexagonal and finely arranged.
　この出願は、２０１７年１２月２８日に日本国特許庁に出願された特許出願第２０１７－２５４３５２号と、２０１８年１２月２６日に日本国特許庁に出願された特許出願第２０１８－２４３５９９号に基づき、その全内容を含むものである。 This application is related to Patent Application No. 2017-254352 filed with the Japanese Patent Office on December 28, 2017, and Patent Application No. 2018-243599 filed with the Japanese Patent Office on December 26, 2018. Based on the entire content.
１０Ａ、１０Ｂ　光学素子
１１、１１１　高分子材料層
１２、１２Ａ、１２Ｂ　第１の電極層
１３、１３Ａ、１３Ｂ　スペーサ層
１４、１４Ａ、１４Ｂ　第２の電極層
１４１　主面
１４３　開口
１４５　底面
１５、１１５　光散乱体
１６　開口
１７　空間
１９Ａ，１９Ｂ　電極アセンブリ
２１　基材
１００　マイクロレンズアレイ
１１０　サンプル
１１２、１１３　電極
１３０　撮像素子アレイ
１３１Ｒ、１３１Ｇ、１３１Ｂ　カラーフィルタ
１５０　撮像装置
２５０　照明装置 10A, 10B Optical element 11, 111 Polymer material layer 12, 12A, 12B First electrode layer 13, 13A, 13B Spacer layer 14, 14A, 14B Second electrode layer 141 Main surface 143 Opening 145 Bottom surface 15, 115 Light Scatterer 16 opening 17 space 19A, 19B electrode assembly 21 base material 100 micro lens array 110 sample 112, 113 electrode 130 imaging element array 131R, 131G, 131B color filter 150 imaging device 250 illumination device

Claims (15)

  1. 　第１の電極層と、
    　第２の電極層と、
    　前記第１の電極層と前記第２の電極層の間に配置される高分子材料層と、
    　前記高分子材料層と前記第２の電極層の間に配置され、前記高分子材料層と前記第２の電極層の間に所定の空間を形成する絶縁性のスペーサ層と、
    を有し、前記高分子材料層は、電圧印加の下で変形して、前記所定の空間に１以上の光散乱体を形成することを特徴とする光学素子。     A first electrode layer,
    A second electrode layer,
    A polymer material layer disposed between the first electrode layer and the second electrode layer;
    An insulating spacer layer disposed between the polymer material layer and the second electrode layer to form a predetermined space between the polymer material layer and the second electrode layer;
    An optical element characterized in that the polymer material layer is deformed under voltage application to form one or more light scatterers in the predetermined space.
  2. 　前記スペーサ層は、１以上の開口を有する絶縁膜であり、
    　前記電圧印加の下で、前記１以上の光散乱体の各々は、対応する前記１以上の開口の中に形成されることを特徴とする請求項１に記載の光学素子。     The spacer layer is an insulating film having one or more openings,
    The optical element according to claim 1, wherein under the application of the voltage, each of the one or more light scatterers is formed in the corresponding one or more apertures.
  3. 　前記第２の電極層は、前記高分子材料層と対向する主面に１以上の開口を有し、
    　前記スペーサ層は、前記主面において、前記１以上の開口の底面を除く領域を覆って設けられ、
    　前記電圧印加の下で、前記１以上の光散乱体の各々は、対応する前記１以上の開口の中に形成されることを特徴とする請求項１に記載の光学素子。     The second electrode layer has one or more openings on the main surface facing the polymer material layer,
    The spacer layer is provided on the main surface so as to cover an area excluding the bottom surface of the one or more openings,
    The optical element according to claim 1, wherein under the application of the voltage, each of the one or more light scatterers is formed in the corresponding one or more apertures.
  4. 　前記光散乱体は、凸形状であることを特徴とする請求項１～３のいずれか１項に記載の光学素子。 The optical element according to any one of claims 1 to 3, wherein the light scattering body has a convex shape.
  5. 　前記第２の電極層は陽極層であり、前記第１の電極層は陰極層であることを特徴とする請求項１～４のいずれか１項に記載の光学素子。 The optical element according to any one of claims 1 to 4, wherein the second electrode layer is an anode layer, and the first electrode layer is a cathode layer.
  6. 　前記第２の電極層は、透明電極層であることを特徴とする請求項１～５のいずれか１項に記載の光学素子。 The optical element according to any one of claims 1 to 5, wherein the second electrode layer is a transparent electrode layer.
  7. 　前記高分子材料層は、ゲル状の高分子材料に２５℃での負イオンの輸率が０．４以上であるイオン液体が添加されていることを特徴とする請求項１～６のいずれか１項に記載の光学素子。 7. The polymer material layer according to claim 1, wherein an ionic liquid having a transport number of negative ions at 25 ° C. of 0.4 or more is added to the gel polymer material. The optical element according to item 1.
  8. 　第１の電極層と、
    　第２の電極層と、
    　前記第１の電極層と前記第２の電極層の間に配置される高分子材料層と、
    　前記高分子材料層と前記第２の電極層の間に配置され、前記高分子材料層と前記第２の電極層の間に所定の空間を形成する絶縁性のスペーサ層と、
    を有し、電圧印加の下で前記第２の電極層の表面に複数の光散乱体の配列を有することを特徴とするマイクロレンズアレイ。     A first electrode layer,
    A second electrode layer,
    A polymer material layer disposed between the first electrode layer and the second electrode layer;
    An insulating spacer layer disposed between the polymer material layer and the second electrode layer to form a predetermined space between the polymer material layer and the second electrode layer;
    A microlens array comprising: an array of a plurality of light scatterers on a surface of the second electrode layer under voltage application.
  9. 　前記高分子材料層は、ゲル状の高分子材料に、２５℃での負イオンの輸率が０．４以上であるイオン液体が添加されていることを特徴とする請求項８に記載のマイクロレンズアレイ。 9. The micro-computer according to claim 8, wherein the polymer material layer comprises an ionic liquid having a transport number of negative ions of at least 0.4 at 25 ° C. added to the gel-like polymer material. Lens array.
  10. 　請求項８または９に記載のマイクロレンズアレイと、
    　前記マイクロレンズアレイに対向して配置される撮像素子アレイと、
    を有することを特徴とする撮像装置。     A microlens array according to claim 8 or 9,
    An imaging element array disposed to face the micro lens array;
    An imaging apparatus characterized by having:
  11. 　請求項８または９に記載のマイクロレンズアレイと、
    　光源と、
    を有することを特徴とする照明装置。     A microlens array according to claim 8 or 9,
    Light source,
    An illuminating device characterized by having.
  12. 　第１の電極層の上に高分子材料層を形成し、
    　前記高分子材料層の上に、絶縁性のスペーサ層と第２の電極層とを配置して、前記高分子材料層と前記第２の電極層の間に所定の空間を形成し、
    　前記第１の電極層と前記第２の電極層の間に電圧を印加して前記高分子材料層を変形させて、前記空間に１以上の光散乱体を形成する、
    工程を含む光学素子の作製方法。     Forming a polymer material layer on the first electrode layer;
    An insulating spacer layer and a second electrode layer are disposed on the polymer material layer to form a predetermined space between the polymer material layer and the second electrode layer,
    A voltage is applied between the first electrode layer and the second electrode layer to deform the polymer material layer to form one or more light scatterers in the space.
    A method of producing an optical element comprising a step.
  13. 　１以上の開口を有する前記スペーサ層を前記第２の電極層に貼り合わせた電極アセンブリを形成し、
    　前記高分子材料層の上に、前記電極アセンブリを配置する、
    ことを特徴とする請求項１２に記載の光学素子の作製方法。     Forming an electrode assembly in which the spacer layer having one or more openings is bonded to the second electrode layer;
    Placing the electrode assembly on the polymeric material layer,
    A method of producing an optical element according to claim 12, characterized in that.
  14. 　前記第２の電極層の主面に１以上の開口を形成し、
    　前記主面において、前記開口の底面を除く領域を覆う前記スペーサ層を形成して電極アセンブリを形成し、
    　前記高分子材料層と前記主面が対向するように、前記高分子材料層の上に前記電極アセンブリを配置する、
    ことを特徴とする請求項１２に記載の光学素子の作製方法。     One or more openings are formed in the main surface of the second electrode layer,
    Forming an electrode assembly by forming the spacer layer covering an area excluding the bottom surface of the opening on the main surface;
    Disposing the electrode assembly on the polymeric material layer such that the polymeric material layer and the major surface face each other;
    A method of producing an optical element according to claim 12, characterized in that.
  15. 　前記高分子材料層は、ゲル状の高分子材料に２５℃での負イオンの輸率が０．４以上であるイオン液体が添加されていることを特徴とする請求項１２～１４のいずれか１項に記載の光学素子の作製方法。 15. The polymer material layer according to any one of claims 12 to 14, wherein an ionic liquid having a transport number of negative ions at 25 ° C of 0.4 or more is added to the gel polymer material. The manufacturing method of the optical element of 1 item.
PCT/JP2018/048301 2017-12-28 2018-12-27 Optical element, and method for producing optical element WO2019131933A1 (en)

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