Optical element, beam control device and manufacturing method thereof, and display

Abstract

To provide an optical element excellent in beam controllability and allowing high integration, a beam control device including the optical element and a manufacturing method of the same, and a display including the beam control device.SOLUTION: An optical element 101 comprises a first transparent substrate 102 including a protrusion 102b on one surface 102a, and a droplet 103 arranged at a tip 102c of the protrusion 102b.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an optical element, a light beam control device and a manufacturing method thereof, and a display. [Background technology]

[0002] Flat panel displays that produce images that can be viewed in 3D with the naked eye are expected to be used in fields such as entertainment and medicine. One technology that has attracted particular attention for use in flat panel displays is light beam control technology, which controls the focus (width) and direction of light beams to create binocular parallax for humans and form 3D images (see, for example, Patent Document 1). Light beam control technology is also used in mirror arrays using microelectromechanical systems, spatial light modulators made of liquid crystal, optical phased arrays, and other devices. Newly developed devices tend to be required to be compact, and as a result, there is a demand for technologies that improve light beam controllability (focus resolution, angular resolution, response speed) and enable even higher integration. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-003688 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention has been made in consideration of the above circumstances, and aims to provide an optical element that has excellent light controllability and enables high integration, a light beam control device equipped with the optical element and a method for manufacturing the same, and a display equipped with the light beam control device. [Means for solving the problem]

[0005] In order to solve the above problems, the present invention employs the following means.

[0006] (1) An optical element according to one aspect of the present invention includes a transparent first substrate having convex portions on one surface thereof, and droplets disposed on the tips of the convex portions.

[0007] (2) In the optical element described in (1) above, the droplets are preferably an ionic liquid or glycerol.

[0008] (3) A light beam control device according to one embodiment of the present invention comprises an optical element described in either (1) or (2), a first electrode arranged around the convex portion on one surface of the first substrate, a transparent second substrate arranged on the opposite side of the first substrate across the droplet and having a surface facing the surface of the first substrate, a second electrode arranged on one surface of the second substrate, and a spacer having one end in contact with the surface of the first substrate and the other end in contact with the surface of the second substrate.

[0009] (4) In the light beam control device described in (3), the first substrate may have a plurality of convex portions on one surface thereof, and the plurality of convex portions may be arranged on the one surface of the first substrate according to a predetermined purpose.

[0010] (5) In the light beam control device described in either (3) or (4), the first electrode may be composed of a single first conductive portion on one surface of the first substrate that surrounds the entire circumference of the convex portion.

[0011] (6) In the light beam control device described in either (3) or (4), the first electrode may be composed of a plurality of first conductive portions arranged at equal intervals along the outer periphery of the convex portion on one surface of the first substrate.

[0012] (7) In the light beam control device described in any one of (3) to (6), the second electrode may be composed of a plurality of second conductive portions arranged at equal intervals on one surface of the second substrate along the periphery of an area facing the convex portion of the first substrate.

[0013] (8) In the light beam control device described in either (6) or (7), when viewed in a plane from the normal direction of one surface of the first substrate or one surface of the second substrate, a plurality of the first conductive parts and a plurality of the second conductive parts are arranged so as to overlap one by one.

[0014] (9) A display according to one aspect of the present invention includes the light beam control device according to any one of (3) to (8) above, and a light source disposed on the other surface side of the first substrate.

[0015] (10) A method for manufacturing a light beam control device according to one embodiment of the present invention is a method for manufacturing a light beam control device described in any one of (3) to (8), and includes the steps of forming a surface on the first substrate having a convex portion, forming the first electrode around the convex portion on the surface of the first substrate, placing the droplet on the tip of the convex portion, forming the second electrode on one surface of the second substrate, and fixing the first substrate and the second substrate via the spacer so that the surface of the first substrate and the surface of the second substrate face each other while being spaced apart. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide an optical element that has excellent light controllability and enables high integration, a light beam control device equipped with the optical element and a method for manufacturing the same, and a display equipped with the light beam control device. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a cross-sectional view of an optical element according to a first embodiment of the present invention. [Figure 2] 1 is a cross-sectional view of a light beam control device according to a first embodiment. [Figure 3] 3(a) to 3(d) are diagrams illustrating a method for manufacturing the light beam control device of the first embodiment. [Figure 4] 3(a) to 3(c) are diagrams illustrating a method for manufacturing the light beam control device of the first embodiment. [Figure 5]3A to 3C are diagrams illustrating a method for arranging droplets that constitute the light beam control device of the first embodiment. [Figure 6] 3A to 3C are diagrams illustrating control of the width of a light beam by the light beam control device of the first embodiment. [Figure 7] 5A and 5B are cross-sectional views of a light beam control device according to a second embodiment of the present invention. [Figure 8] 6(a) to 6(d) are diagrams illustrating a method for manufacturing a light beam control device according to the second embodiment. [Figure 9] 5(a) to 5(c) are diagrams illustrating a method for manufacturing a light beam control device according to a second embodiment. [Figure 10] 10A and 10B are diagrams illustrating control of the direction and width of a light beam by a light beam control device according to a second embodiment. [Figure 11] 10A to 10C are diagrams illustrating control of the direction and width of a light beam by a light beam control device according to Modification 1 of the second embodiment. [Figure 12] 10(a) and 10(b) are a plan view and a cross-sectional view of a light beam control device according to a second modification of the second embodiment. [Figure 13] FIG. 10 is a perspective view of a light beam control device according to a third modified example of the second embodiment. [Figure 14] 10A to 10C are diagrams illustrating the operation of a display including a light beam control device according to a second embodiment. [Figure 15] 1 is an image of a droplet produced as an example. [Figure 16] 10 is an image of a spot of a transmitted light beam obtained using the light beam control device of the embodiment. [Figure 17] 1A is a diagram showing a change in the shape of a droplet, and FIG. 1B is an image showing the electric field distribution around the droplet. [Figure 18] 10A is a diagram showing a change in the shape of a droplet, and FIG. 10B is an image showing the electric field distribution around the droplet, showing the results of a simulation of the light beam control device according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an optical element, a light beam control device and a manufacturing method thereof, and a display according to embodiments of the present invention will be described in detail with reference to the drawings. Note that the drawings used in the following description may show characteristic parts enlarged for the sake of clarity, and the dimensional ratios of each component may not necessarily be the same as in reality. Furthermore, the materials, dimensions, etc. exemplified in the following description are merely examples, and the present invention is not limited thereto. Appropriate modifications can be made within the scope of the present invention.

[0019] First Embodiment [Optical elements] 1 is a cross-sectional view of an optical element 101 according to a first embodiment of the present invention. The optical element 101 mainly comprises a first substrate 102 and a droplet 103.

[0020] The first substrate 102 has protruding portions 102b on one substantially flat surface (one main surface) 102a. A protruding direction P of the protruding portions 102b is substantially perpendicular to the surface 102a. A droplet 103 is disposed on a tip (tip surface) 102c of the protruding portion 102b. The protruding portion 102b functions as a base that supports the droplet 103 without deforming it. To enhance the support function for the droplet 103, the tip (tip surface) 102c of the protruding portion 102b may be fluorinated with a fluorine-based process gas (C4F8) or the like.

[0021] The shape of the convex portion 102b is not particularly limited, but may be, for example, a columnar shape such as a cylinder or a rectangular pillar. From the viewpoint of stably supporting the droplet 103, it is preferable that the tip 102c of the convex portion that comes into contact with the droplet 103 is a flat surface. It is preferable that the ratio of the width W of this flat surface to the diameter (maximum diameter) D of the droplet 103 to be supported is 5% or more and 100% or less. If this ratio is less than 5%, the droplet 103 may break. Also, if this ratio is less than 100%, % If it is larger, the droplet 103 may spread along the tip surface and may not be able to maintain its shape.

[0022] The height H of the convex portion 102b (the length of protrusion from the surface 102a) is preferably 100 nm or more and 10,000 nm or less. If the height H is less than 100 nm, the difference in level with the surface 102a becomes small, which makes it easier for the droplet 103 to spread outside the tip surface and may prevent it from maintaining its spherical shape. If the height H is made greater than 10,000 nm, the convex portion 102b will be larger, which will require more work to process and will require a larger space to be secured.

[0023] The first substrate 102 is a transparent substrate that transmits at least visible light (electromagnetic waves with a wavelength of about 380 to 770 nm). Examples of materials that can be used for the first substrate 102 include glass such as quartz, a transparent conductive substrate, and a transparent resin.

[0024] The droplets 103 are not particularly limited as long as they are non-volatile liquids that do not volatilize at temperatures below 25°C and can form spherical structures by surface tension when dropped onto the tip surface 102c of the convex portion of the first substrate 102. Examples of non-volatile liquids include liquids with a surface tension of 30 mJ / m 2 Ionic liquids with a surface tension of 30 mJ / m or more, ionic liquids containing any of imidazolium, pyrrolidinium, pyridinium, piperidinium, ammonium, and phosphonium as cations, or ionic liquids containing any of fluoride, chloride, bromide, iodide, tetrafluoroborate, hexafluorophosphate, hexafluoroantimonate, bistrifluoromethylsulfonylimide, trifluoromethanesulfonate, methyl sulfate, acetate, dicyandiamide, and dimethyl phosphate, or glycerol are preferably used. 2 As an ionic liquid exceeding this limit, for example, imidazolium tetrafluoroborate represented by the following formula (1) or glycerol is preferably used.

[0025] [ka] [wherein R1 is an alkyl group having 1 to 6 carbon atoms, and R2 is an alkyl group having 2 to 10 carbon atoms.]

[0026] Among imidazolium tetrafluoroborates, 1-ethyl-3-methylimidazolium tetrafluoroborate represented by the following formula (2) is preferred.

[0027] [ka]

[0028] [Beam control device] 2 is a cross-sectional view of a light beam control device 100 according to a first embodiment of the present invention. The light beam control device 100 mainly includes the above-described optical element 101, a first electrode 104, a second substrate 105, a second electrode 106, and a spacer 107.

[0029] The first electrode 104 is a transparent conductor (transparent conductive film) disposed around the convex portion 102b on the first surface 102a of the first substrate. The material of the first electrode 104 is not particularly limited, but examples thereof include ITO (indium tin oxide) and PEDOT:PSS. The first electrode 104 of this embodiment is disposed on the first surface 102a of the first substrate and is composed of a single first conductive portion (transparent conductive film) 104A that surrounds the entire periphery of the convex portion 102b. The thickness of the first electrode 104 is preferably uniform throughout, and is preferably 1 nm or more and 1000 nm or less. The first electrode 104 is connected to a first power source 104B, and the potential V1 of the first electrode 104 can be controlled using the first power source 104B.

[0030] The second substrate 105 is disposed on the opposite side of the first substrate 102 across the droplet 103 so as to cover the droplet 103, and has a surface 105a facing the surface 102a of the first substrate. That is, the surface 105a of the second substrate faces the surface 102a of the first substrate across the droplet 103. The second substrate 105 is a transparent substrate that transmits at least visible light. Examples of materials that can be used for the second substrate 105 include glass such as quartz, a transparent conductive substrate, and a transparent resin.

[0031] The second electrode 106 is a transparent conductor (transparent conductive film) disposed on one surface (one main surface) 105a of the second substrate. The constituent material of the second electrode 106 is not particularly limited, but examples thereof include ITO and PEDOT:PSS. The second electrode 106 of this embodiment is composed of one second conductive portion 106A disposed on the one surface 105a of the second substrate. The thickness of the second electrode 106 is preferably uniform throughout, and is preferably 1 nm or more and 1000 nm or less. The second electrode 106 is connected to a second power source 106B, and is configured so that the potential V2 of the second electrode 106 can be controlled using the second power source 106B.

[0032] Spacer 107 is a member that ensures a space between first substrate 102 and second substrate 105, and is arranged so that one end 107a contacts one surface 102a of the first substrate and the other end 107b contacts one surface 105a of the second substrate. Spacers 107 are not particularly limited in number, shape, or size as long as they are arranged so that the distance between first substrate 102 and second substrate 105 is uniform. The material that makes up spacer 107 is not particularly limited, but examples include insulating resin, glass beads, etc.

[0033] [Method of manufacturing the light beam control device] 3(a) to 3(d) and 4(a) to 4(c) are diagrams illustrating a method for manufacturing a light beam control device according to this embodiment. The method for manufacturing a light beam control device mainly includes the following five steps.

[0034] (Protrusion forming process) 3(a), only the region R where the convex portion 102b is to be formed (the region where the droplet 103 is to be disposed) of one surface 102d of the first substrate 102 is covered with a resist 108 by photolithography. The width (diameter) of the region R is set to, for example, 20 μm.

[0035] 3(b), the area of ​​the first surface 102d of the first substrate 102 that is not covered with the resist 108 is removed by etching. After etching, the first substrate 102 is left with a convex portion 102b formed on the newly formed first surface 102a. The height H of the convex portion can be adjusted by the amount of etching.

[0036] (First electrode formation process) 3(c), a transparent conductive material is sputtered from the side facing the surface 102a including the protrusions 102b (here, the upper side), to form a transparent conductive film 104A all around the surface 102a around the protrusions 102b and on the resist 108. The amount of sputtering (voltage, time) is adjusted so that the transparent conductive film 104A has a thickness suitable for the first electrode 104, for example, about 200 nm.

[0037] 3(d), the resist 108 and the transparent conductive film 104A formed thereon are lifted off by cleaning with acetone or the like. The transparent conductive film 104A remaining around the convex portion 102b corresponds to the first electrode 104. The tip surface 102c of the convex portion exposed after lift-off is preferably fluorinated with a fluorine-based process gas (C4F8).

[0038] (Droplet placement process) As shown in FIG. 4(a), spherical droplets 103 are placed on the tip surface 102c of the convex portion. The droplets 103 can be placed using, for example, an inkjet method. FIG. 5 is a diagram illustrating a method for placing droplets using the inkjet method. The droplets can be placed using an inkjet device 10 shown in FIG. 5.

[0039] The inkjet device 10 is a device that utilizes (applies) the principles of a so-called inkjet printer and is configured to eject droplets 103 of this embodiment instead of printing ink. The inkjet device 10 mainly comprises a liquid storage unit 11, a liquid flow path 12, a droplet ejection unit 13, a piezoelectric element 14, a substrate holding unit 15, and a housing 16. The droplet ejection unit 13 ejects highly viscous droplets and is therefore configured to have a higher ejection pressure than the ink ejection unit of a typical inkjet printer. The substrate holding unit 15 is a holder (such as an XYZ motorized stage) for the first substrate 102 after the first electrode formation process, onto which the droplets 103 are dropped. While the configuration of each unit is shown in a simplified form in FIG. 5, various design modifications are possible depending on the application.

[0040] In the inkjet device 10 of Fig. 5, the non-volatile liquid 103A described above is stored in the liquid storage unit 11. Furthermore, the first substrate 102 after the first electrode formation step is held on the substrate holding unit 15 so that the tip surfaces 102c of the convex portions face the droplet discharge unit 13. Furthermore, the position of the substrate holding unit 15 relative to the droplet discharge unit 13 is adjusted. Then, the non-volatile liquid 103A that has reached the droplet discharge unit 13 from the liquid storage unit 11 via the liquid flow path 12 is discharged in the form of droplets 103 onto the tip surfaces 102c of the convex portions of the first substrate 102 using the piezoelectric element 14.

[0041] (Second electrode formation process) 4(b), a transparent conductive material is sputtered from the side facing one surface 105a of the second substrate 105 (here, the lower side) to form a transparent conductive film 106A on one surface 105a. This transparent conductive film 106A corresponds to the second electrode 106. The amount of sputtering (voltage, time) is adjusted so that the transparent conductive film 106A has a thickness suitable for the second electrode, for example, about 200 nm.

[0042] (Substrate fixing process) 4(c), the positional relationship between the first substrate 102 and the second substrate 105 is fixed via the spacer 107 so that one surface 102a of the first substrate and one surface 105a of the second substrate face each other while being spaced apart from each other, thereby obtaining the light beam control device 100. The shape of the spacer 107 is not particularly limited, but may be, for example, a columnar shape such as a cylindrical or rectangular columnar shape.

[0043] The spacer 107 has a size that separates the first substrate 102 and the second substrate 106 to such an extent that the droplet 103 arranged on the tip surface 102c of the convex portion does not come into contact with the second electrode 106. One end 107a of the spacer and the first substrate 102 (first electrode 104), and the other end 107b of the spacer and the second substrate 105 (first electrode 105), may be bonded using an adhesive or the like. Examples of materials that can be used to form the spacer 107 include insulating resins and glass beads.

[0044] The optical element 101 itself is obtained by carrying out the above-described convex portion forming step and droplet disposing step in this order.

[0045] [Method for controlling light beams using a light beam control device] 6(a) and 6(b) are diagrams illustrating the control of the width of a light beam by the light beam control device 100. Here, the spacer 107, the first power source 104B, and the second power source 106B are not shown.

[0046] 6(a) shows a state in which a light ray L is emitted from the light source 108 from the outside of the first substrate 102 (here, the lower side) toward the outside of the second substrate 105 (here, the upper side) with no voltage applied between the first electrode 104 and the second electrode 106 (V2=V1). The light source 108 is disposed so that the traveling direction of the light ray L overlaps with the protruding direction P of the convex portion 102b of the first substrate 105. Here, a case is illustrated in which the light ray is directly incident on the first substrate 102 from the light source 108, but a predetermined optical device (lens, mirror, etc.) may be interposed between the light source 108 and the first substrate 102 as needed.

[0047] In this state, the droplet 103 maintains its spherical shape because no electric field is generated between the first electrode 104 and the second electrode 106. Therefore, the light ray L incident from the first electrode 104 passes through the spherical droplet 103 and exits from the second electrode 105 with a width slightly wider than before passing through.

[0048] 6(b) shows a state in which a voltage is applied between the first electrode 104 and the second electrode 106 (V2>V1), and a light beam L is irradiated from the outside of the first substrate 102 toward the outside of the second substrate 105 using the light source 108. In this state, an electric field E is generated between the first electrode 104 and the second electrode 106, which causes the interface of the droplet 103 to deform.

[0049] The first electrode 104 is disposed symmetrically in all directions from the outer periphery of the convex portion 102b. Similarly to the first electrode 104, the second electrode 106 is disposed symmetrically in all directions from the outer periphery of the region R3 that overlaps with the convex portion 102b, i.e., the region R3 directly above the convex portion 102b. Therefore, the direction of the electric field E generated between the first electrode 104 and the second electrode 106 is almost straight and is substantially parallel to the protruding direction of the convex portion 102b (here, the up-and-down direction).

[0050] Therefore, droplet 103, affected by this electric field E, expands overall in the protruding direction of convex portion 102b and contracts in a direction perpendicular to the protruding direction. As a result, light ray L incident from first electrode 104 passes through droplet 103 whose interface has been deformed, and is emitted from second electrode 106 with a wider width than before passing through. The width of light ray L here is wider than when no voltage is applied.

[0051] The interfacial deformation of the droplet 103 increases in proportion to the magnitude of the applied electric field E. Therefore, the magnitude of the interfacial deformation of the droplet 103 can be controlled by the voltage applied between the first electrode 104 and the second electrode 106, and therefore the width of the light beam L passing through the droplet 103 can be controlled.

[0052] As described above, the light beam control device of this embodiment utilizes the property of droplets that their interface regularly deforms when a voltage is applied. When a droplet is spherical, the increase in the width of the light beam passing through the droplet is very small compared to before transmission. However, when the droplet's interface deforms due to the application of a voltage, the width of the light beam passing through the droplet significantly increases compared to before transmission. The greater the deformation of the droplet's interface, the wider the width of the transmitted light beam.

[0053] The light beam control device of this embodiment is equipped with droplets of such properties and a means for applying a voltage to the droplets, thereby deforming the droplets with the voltage and changing the width of the light beam passing through the droplets, thereby making it possible to control the light beam with high precision. Furthermore, because the light beam control device of this embodiment uses minute droplets as a means for controlling the light beam, it does not require a large space and can be highly integrated.

[0054] Second Embodiment [Beam control device] Fig. 7 is a cross-sectional view of a light beam control device 200 according to a second embodiment of the present invention. Fig. 7(a) is a cross-sectional view parallel to the stacking direction of the first substrate 102 and the second substrate 105. Fig. 7(b) is a cross-sectional view excluding the second substrate 105, the second electrode 106, and the spacer 107.

[0055] The light beam control device 200 differs from the light beam control device 100 of the first embodiment mainly in that the first electrode 104 is composed of a plurality of first conductive portions 104A. That is, the first electrode 104 is composed of a plurality of first conductive portions 104A arranged at equal intervals along the outer periphery of the convex portion 102b on one surface 102a of the first substrate. The other configurations are similar to those of the light beam control device 100, and the light beam control device 200 can achieve at least the same effects as the light beam control device 100. The same reference numerals as in the first embodiment are used for components similar to or corresponding to those in the first embodiment.

[0056] 7(a) and (b) illustrate an example in which the first electrode 104 is composed of two first conductive portions 104A arranged at equal intervals along the outer periphery of the convex portion 102b on one surface 102a of the first substrate. In addition to the convex portion 102b, the first substrate 102 of this embodiment has two convex portions 102e on one surface. The two convex portions 102e are formed spaced apart from the convex portion 102b, with the convex portion 102b sandwiched between them. The first conductive portions 104A are formed at the tips of the two convex portions 102e. A first conductive portion 104A is also formed at the tip of the convex portion 102b, but this is electrically insulated from the first conductive portion 104A formed at the tip of the convex portion 102e.

[0057] [Method of manufacturing the light beam control device] 8(a) to 8(d) and 9(a) to 9(c) are diagrams illustrating a method for manufacturing a light beam control device according to this embodiment. The method for manufacturing a light beam control device mainly includes the following five steps.

[0058] (First electrode formation process) As shown in Fig. 8(a), photolithography is used to cover only two regions R1 and R2 around a region R (region where droplets 103 are disposed) where convex portions 102b are to be formed on one surface 102d of the first substrate 102 with resist 108. As shown in Fig. 7(b), regions R1 and R2 are located on opposite sides of convex portions 102b and are aligned with region R on a straight line S. The width (diameter) of regions R1 and R2 is, for example, 20 µm.

[0059] 8(b), sputtering of a transparent conductive material and sputtering of gold (Au) are performed in this order from the side facing one surface 102d (here, the upper side), to form a transparent conductive film 104A and a gold film 109 on one surface 102d and the upper surface of the resist 108. The amount of sputtering (voltage, time) is adjusted so that the transparent conductive film 104A and the gold film 109 have predetermined thicknesses.

[0060] 8(c), cleaning with acetone or the like is performed to lift off the resist 108, the transparent conductive film 104A formed thereon, and the gold film 109. The transparent conductive film 104A remaining around regions R1 and R2 corresponds to the first electrode 104.

[0061] (Protrusion forming process) As shown in Fig. 8(d), regions R1 and R2 of one surface 102d of the first substrate 102 that are not covered with the gold film 109 are removed by etching. After etching, the first substrate 102 is left with a convex portion 102b formed on the newly formed one surface 102a. The height H of the convex portion can be adjusted by the amount of etching.

[0062] (Droplet placement process) 9(a), a spherical droplet 103 is placed on the tip surface 102c of the convex portion. The droplet 103 can be placed by using, for example, the inkjet method described above.

[0063] (Second electrode formation process) 9(b), a transparent conductive material is sputtered from the side facing one surface 105a of the second substrate 105 (here, the lower side) to form a transparent conductive film 106A on one surface 105a. This transparent conductive film 106A corresponds to the second electrode 106. The amount of sputtering (voltage, time) is adjusted so that the transparent conductive film 106A has a thickness suitable for the second electrode 106, for example, about 200 nm.

[0064] (Substrate fixing process) As shown in Figure 9(c), the positional relationship between the first substrate 102 and the second substrate 105 is fixed via the above-mentioned spacer 107 so that one surface 102a of the first substrate and one surface 105a of the second substrate face each other while being spaced apart, thereby obtaining the light beam control device 200.

[0065] [Method for controlling light beams using a light beam control device] 10(a) and 10(b) are diagrams illustrating the control of the direction and width of the light beam L by the light beam control device 200. Here, the spacer 107, the first power source 104B, and the second power source 106B are not shown.

[0066] 10(a) shows a state in which a light ray L is emitted from the light source 108 from the outside of the first substrate 102 (here, the lower side) toward the outside of the second substrate 105 (here, the upper side) with no voltage applied between the first electrode 104 and the second electrode 106 (V2=V1). The light source 108 is disposed so that the traveling direction of the light ray L overlaps with the protruding direction P of the convex portion 102b of the first substrate 105. Here, a case is illustrated in which the light ray is directly incident on the first substrate 102 from the light source 108, but a predetermined optical device (lens, mirror, etc.) may be interposed between the light source 108 and the first substrate 102 as necessary.

[0067] In this state, the droplet 103 maintains its spherical shape because no electric field is generated between the first electrode 104 and the second electrode 106. Therefore, the light ray L incident from the first electrode 104 passes through the spherical droplet 103 and exits from the second electrode 106 with a width slightly wider than before passing through.

[0068] 10(b) shows a state in which a light beam L is irradiated from the outside of the first substrate 102 toward the outside of the second substrate 105 using the light source 108, with a voltage (V2>V1) being applied between only one (here, the right side) of the two first conductive portions 104A constituting the first electrode 104 and the second electrode 106. In this state, an electric field E is generated between the first electrode 104 and the second electrode 106, which in turn deforms the interface of the droplet 103.

[0069] The arrangement of first electrode 104 to which a voltage is applied is not symmetrical in all directions from the outer periphery of convex portion 102b, and therefore the direction of electric field E generated between first electrode 104 and second electrode 106 is oblique, and includes a component in a direction inclined from the protruding direction of convex portion 102b (here, the vertical direction).

[0070] Therefore, droplet 103, affected by this electric field E, stretches overall in a direction tilted from the protruding direction P of convex portion 102b, and shrinks in a direction perpendicular to this tilt. As a result, light ray L incident from first electrode 104 passes through droplet 103 with its interface deformed, and its direction of travel changes compared to before passing through, and it is emitted from second electrode 106 with an increased width. The increase in the width of light ray L here is greater than when no voltage is applied.

[0071] The direction of the interfacial deformation of the droplet 103 changes depending on the direction of the electric field E acting on the droplet 103, and therefore can be controlled by the arrangement and selection of the first electrode 104 to which the voltage is applied, and thus the direction of the light beam L can be controlled. Also in this case, the interfacial deformation of the droplet 103 increases in proportion to the magnitude of the acting electric field E. Therefore, the magnitude of the interfacial deformation of the droplet 103 can be controlled by the voltage applied between the first electrode 104 and the second electrode 106, and thus the width of the light beam passing through the droplet 103 can be controlled.

[0072] Note that, by applying the same voltage to all of the first conductive portions 104A constituting the first electrode 104, an electric field E can be generated in a straight direction along the protruding direction of the convex portions 102b. Therefore, the light beam control device 200 according to this embodiment can also control only the width of the light beam L, similar to the light beam control device 100 according to the first embodiment.

[0073] 11 is a diagram illustrating control of the direction and width of the light beam L by the light beam control device 210 of the first modified example of the second embodiment. Here, the spacer 107, the first power source 104B, and the second power source 106B are not shown.

[0074] The light beam control device 210 differs from the light beam control device 200 only in that the second electrode 106 is made up of a plurality of second conductive portions 106A arranged at equal intervals on one surface of the second substrate along the periphery of a region R3 that faces the convex portion of the first substrate. Here, an example is shown in which the second electrode 106 is made up of two second conductive portions 106A arranged at equal intervals on one surface 105a of the second substrate along the periphery of a region R3 that overlaps with the convex portion 102b. The two second conductive portions 106A are formed on either side of the region R3 that overlaps with the convex portion 102b, and are spaced apart from this region R3.

[0075] By selecting the conductive portion to which a voltage is applied in each of the first electrode 104 and the second electrode 106, the direction of the generated electric field E can be narrowed to a specific direction. Here, a voltage is applied between only one (here, the right side) of the two first conductive portions 104A constituting the first electrode 104 and only one (here, the left side) of the two second conductive portions 106A constituting the second electrode 106 (V2>V1). In this state, light source 108 is used to irradiate light beam L from outside first substrate 102 toward outside second substrate 105.

[0076] In this case, an electric field E is generated in one direction along the diagonal line across the droplet 103, causing the interface of the droplet 103 to deform so as to tilt in that direction. Since the light beam control device 210 can narrow the direction of the generated electric field E, it is possible to precisely control the deformation of the droplet 103 so that it deforms in a specific direction, and ultimately to improve the controllability of the direction of the light beam L.

[0077] When both the first electrode 104 and the second electrode 106 are made up of multiple conductive parts, as in the light beam control device 210, it is preferable to arrange the respective conductive parts so that they overlap one-to-one. That is, it is preferable to arrange the multiple first conductive parts 104A and the multiple second conductive parts 106A so that they overlap one-to-one in a plan view from the normal direction N (the vertical direction in FIG. 11 ) of the one surface 102a of the first substrate or the one surface 105a of the second substrate. By arranging them in this manner, it becomes easier to understand how to control the voltage required to deform the droplet 103 in the desired direction, and as a result, the controllability of the light beam L can be improved.

[0078] 12 is a plan view and a cross-sectional view of a light beam control device 220 according to Modification 2 of the second embodiment. In the light beam control device 220, the first electrode 104 is made up of three first conductive portions 104A arranged at equal intervals along the outer periphery of the protrusion 102b on one surface 102a of the first substrate. The rest of the configuration is the same as that of the light beam control device 200 shown in FIGS. 7(a) and 7(b).

[0079] In the light beam control device 200, by applying a voltage to one of the two first conductive portions 104A, the direction in which the droplet 103 deforms can be tilted, thereby changing the direction of travel of the light beam L passing through the droplet 103. However, the direction in which the deformation direction of the droplet 103 can be tilted is limited to one plane including the two first conductive portions 104A. In contrast, in the light beam control device 220, by applying a voltage to one or two of the three first conductive portions 104A, the deformation direction of the droplet 103 can be tilted in multiple planes. Furthermore, by adjusting the magnitude of the voltage applied to each first conductive portion 104A, an electric field can be generated in any direction, so the deformation direction of the droplet 103 can be tilted in any direction.

[0080] 13 is a perspective view of a light beam control device 230 according to Modification 3 of the second embodiment. In the light beam control device 230, the first electrode 104 is made up of four first conductive portions 104A arranged at equal intervals along the outer periphery of the convex portion 102b on one surface 102a of the first substrate. The rest of the configuration is the same as that of the light beam control device 200 shown in FIGS. 7(a) and 7(b).

[0081] In the light beam control device 230, by adjusting which of the four first conductive parts 104A to apply voltage to or how much voltage to apply, the deformation direction of the droplet 103 can be tilted in any direction, just like the light beam control device 220 of variant example 2.

[0082] By applying a configuration in which the second electrode 106 is made up of multiple second conductive parts as in variant 1 to the light beam control devices 220 and 230 of variants 2 and 3, the direction of the generated electric field E can be narrowed, and the deformation direction of the droplet 103 can be finely controlled, thereby improving the controllability of the direction of the light beam L.

[0083] [display] FIG. 14 is a diagram illustrating the operation of a display 300 including the light beam control device 200 of the second embodiment. Here, the spacer 107, the first power source 104B, and the second power source 106B are not shown. The display 300 mainly includes the light beam control device 200 and a light source 108 disposed on the other surface 102f (other main surface) of the first substrate 102. In this case, the light beam control device 200 has a plurality of convex portions 102b on the one surface 102a of the first substrate. The plurality of convex portions 102b are arranged on the one surface 102a of the first substrate according to a predetermined purpose. A droplet 103 is disposed on the tip 102c of each convex portion. By individually controlling the width and direction of the light beam L emitted from the light source L for each droplet 103 as described above, a desired three-dimensional image can be projected.

[0084] As described above, the light beam control device of this embodiment utilizes the properties of a droplet, which undergoes regular interfacial deformation when a voltage is applied, and the properties of a droplet, which deforms in the direction of the electric field generated by the applied voltage. By applying a voltage between a first electrode and a second electrode facing each other across the droplet, an electric field is generated in the direction connecting the first and second electrodes. At this time, the droplet stretches in the direction of the electric field and contracts in the direction perpendicular to the electric field, resulting in a shape tilted in the direction of the electric field. Light rays transmitted through the droplet then travel in the direction of the electric field, and the width of the transmitted light beam is larger than when no voltage is applied.

[0085] The light beam control device of this embodiment is equipped with droplets having these properties and a means for applying a voltage to the droplets, and by applying the voltage to deform the droplets so that they tilt in a specific direction, and by changing the width and direction of the light beam passing through the droplets, it is possible to control the light beam with high precision. Furthermore, because the light beam control device of this embodiment also uses minute droplets as the light beam control means, it does not require a large space and can be highly integrated. [Example]

[0086] The effects of the present invention will be made clearer by the following examples. Note that the present invention is not limited to the following examples and can be practiced with appropriate modifications within the scope of the present invention.

[0087] Example 1 A light beam control device was manufactured according to the first embodiment under the following conditions: The first and second substrates were made of quartz glass. The convex portion of the first substrate was cylindrical, with a tip area of ​​400 μm 2 The height was 1.2 μm. ITO films were used as the first electrode and the second electrode. 1-ethyl-3-methylimidazolium tetrafluoroborate represented by the above formula (2) was used as the droplets, and they were placed on the convex portions using an inkjet device so that the diameter was 30 μm.

[0088] Figure 15 is an SEM image of the droplets that make up the manufactured light beam control device. It can be seen that spherical droplets are arranged on the tips of multiple convex portions formed on the first substrate.

[0089] The light beam transmitted through the droplet was photographed with a camera when the voltage V applied between the first and second electrodes was 0 V and when it was 200 V. Figure 16 shows the spot of the transmitted light beam obtained in each case. Comparing the two spots, it can be seen that the spot when voltage was applied was larger. The divergence angles of the light beam transmitted through the droplet were 0.588 degrees and 0.611 degrees when the applied voltage was 0 V and 200 V, respectively. These results indicate that the droplet was deformed by applying a voltage between the first and second electrodes, and therefore the width of the light beam transmitted through the droplet became wider.

[0090] Example 2 A simulation was performed on the light beam control device of the first embodiment. The convex portion of the first substrate was columnar, with the width of the tip of the convex portion being 30 μm and the height being 1.2 μm. The initial shape of the droplet was spherical, with a diameter of 35 μm. The distance between the first electrode and the second electrode was 100 μm. The density of the droplet was 1.290×10 3 kg / m 3 The viscosity of the droplet is 3.746 × 10 -2 The relative permittivity of the droplet was set to 12.9 Pa·s, and the conductivity of the droplet was set to 1.411 S / m. The contact angle of the droplet with the convex portion was set to 121 degrees. The density and viscosity of the gas surrounding the droplet were set to 1.180 kg / m 3 , 1.822×10 -5 The applied voltage was 0V to 1000V.

[0091] FIG. 17(a) shows the results of a simulation of the change in droplet shape due to the application of voltage. It can be seen that a spherical droplet is deformed by the application of voltage. It expands in the direction in which the convex portion protrudes (here, the up-and-down direction) and contracts in the direction perpendicular to the direction in which the convex portion protrudes (here, the left-and-right direction). The amount of deformation increases as the applied voltage increases. From this result, it can be seen that in the light beam control device of the first embodiment, by applying a voltage between the first electrode and the second electrode, the droplet can be deformed in the direction in which the convex portion protrudes.

[0092] Figure 17(b) is an image showing the simulated electric field distribution around the droplet. It can be seen that the electric field at the droplet location is in the same direction (vertical in this case) as the electric field on the first electrode. From the results obtained from Figures 17(a) and (b), it can be seen that the droplet stretches in the direction of the electric field and shrinks in the direction perpendicular to the electric field.

[0093] Example 3 A simulation was performed on the light beam control device of the second embodiment. The convex portion of the first substrate was made columnar, with the width of its tip set to 30 μm and the height set to 1.2 μm. The initial shape of the droplet was set to a sphere, with a diameter set to 30 μm. The first electrode at the lower right of the droplet and the second electrode at the upper left of the droplet were selected as the electrodes to which a voltage was applied. The distance between the first electrode and the second electrode to which a voltage was applied was set to 50 μm. The density of the droplets was set to 1.290×10 3 kg / m 3 The viscosity of the droplet is 3.746 × 10 -2 The relative permittivity of the droplet was set to 12.9 Pa·s, and the conductivity of the droplet was set to 1.411 S / m. The contact angle of the droplet with the convex portion was set to 121 degrees. The density and viscosity of the gas surrounding the droplet were set to 1.180 kg / m 3 , 1.822×10 -5 The applied voltage was 0 V and 1000 V.

[0094] FIG. 18(a) is a diagram showing the results of a simulation of the change in droplet shape due to the application of voltage. It can be seen that a spherical droplet is deformed by the application of voltage. It shrinks in the direction in which the convex portions protrude (here, the up-and-down direction) and extends in a direction perpendicular to the direction in which the convex portions protrude (here, the left-and-right direction). From this result, it can be seen that in the light beam control device of the second embodiment, by applying a voltage between the first electrode and the second electrode, it is possible to deform the droplet in a direction intersecting the direction in which the convex portions protrude. It is thought that if the applied voltage is reduced, the droplet can be deformed in an oblique direction.

[0095] Figure 18(b) is an image showing the simulation results of the electric field distribution around the droplet. It can be seen that the electric field at the droplet location is applied from the first electrode side (here, the right side) to the second electrode side (here, the left side). From the results obtained from Figures 18(a) and (b), it can be seen that the droplet expands in the direction of the electric field and contracts in the direction perpendicular to the electric field. [Industrial Applicability]

[0096] The present invention can be used in devices such as light emitting elements and optical modulators of flat displays for projection of autostereoscopic images. [Explanation of symbols]

[0097] 100, 200, 210, 220, 230.... Light control device 101 Optical elements 102...First board 102a: One surface of the first substrate after processing 102b, 102e: Convex portions of the first substrate 102c: Tip of convex part (tip surface) 102d: One side of the first substrate before processing 102f: Other side of first substrate 103...droplet 104...first electrode 104A...First conductive part (transparent conductive film) 104B...First power supply 105...Second board 105a: One surface of second substrate 106...Second electrode 106A...Second conductive part (transparent conductive film) 106B...Second power supply 107 Spacer 108···Resist 109...gold film 10. Inkjet device 11 Liquid storage section 12. Liquid flow path 13...Droplet discharge part 14. Piezoelectric element 15... Board holding part 16....Enclosure D...Droplet diameter E...Electric field H: Height of the convex part L...rays L1, L2: Width of the light beam P... Projection direction of the convex part R, R1, R2, R3...area W: Width of the tip of the convex part

Claims

1. a transparent first substrate having a convex portion on one surface; a droplet disposed at the tip of the convex portion.

2. 2. The optical element according to claim 1, wherein the droplets are an ionic liquid or glycerol.

3. The optical element according to claim 1 or 2; a first electrode disposed around the protrusion on one surface of the first substrate; a transparent second substrate disposed on the opposite side of the first substrate with the droplet interposed therebetween, the second substrate having a surface facing the surface of the first substrate; a second electrode disposed on one surface of the second substrate; a spacer having one end in contact with one surface of the first substrate and the other end in contact with one surface of the second substrate.

4. The first substrate has a plurality of the protrusions on one surface thereof, 4. The light beam control device according to claim 3, wherein a plurality of the protrusions are arranged on one surface of the first substrate according to a predetermined purpose.

5. 4. The light beam control device according to claim 3, wherein the first electrode is formed of a single first conductive portion that surrounds the entire periphery of the convex portion on one surface of the first substrate.

6. 4. The light beam control device according to claim 3, wherein the first electrode is made up of a plurality of first conductive portions arranged at equal intervals along the outer periphery of the convex portion on one surface of the first substrate.

7. The light beam control device according to claim 6, characterized in that the second electrode consists of a plurality of second conductive portions arranged at equal intervals along the periphery of an area on one surface of the second substrate that faces the convex portion of the first substrate.

8. The light beam control device according to claim 7, characterized in that, when viewed in a planar view from the normal direction of one surface of the first substrate or one surface of the second substrate, a plurality of the first conductive parts and a plurality of the second conductive parts are arranged so as to overlap one by one.

9. The light beam control device according to claim 3; a light source disposed on the other surface side of the first substrate.

10. A method for manufacturing a light beam control device according to claim 3, forming a surface of the first substrate having a convex portion; forming the first electrode around the protrusion on one surface of the first substrate; placing the droplet on the tip of the convex portion; forming the second electrode on one surface of the second substrate; and a step of fixing the first substrate and the second substrate via the spacer so that one surface of the first substrate and one surface of the second substrate face each other while being spaced apart.

Images