Display device and display method

Abstract

To provide a display device that can switch a display between a three-dimensional display and a second-dimensional display with a simple configuration.SOLUTION: A display device includes: a panel; a first micro lens array arranged on a display surface side of the panel, the first micro lens array having a first electrode with a plurality of openings, a transparent electrode facing the first electrode, and a dielectric and transparent high-polymer material located between the first electrode and the transparent electrode; a second micro lens array arranged on a light emission side of the first micro lens array, the second micro lens array having a plurality of convex lenses; and a controller for controlling application of voltages on the first micro lens array, the first micro lens array generating a concave lens in the openings by application of a voltage, and the controller controlling the voltage applied on the first micro lens array and controlling the state of generation of the concave lens to switch a display between a three-dimensional display and a two-dimensional display.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a display device and a display method, and more particularly to a display device and a display method that are capable of switching between three-dimensional display and two-dimensional display. [Background technology]

[0002] In recent years, three-dimensional (hereafter referred to as "3D") image display has been adopted in games, movies, television broadcasts, and more. A 3D image is an image in which objects appear three-dimensional to the viewer, or in which objects appear to pop out or have a sense of depth. In addition to traditional glasses-based 3D displays, head-mounted displays (HMDs) that display virtual reality content in three dimensions are also becoming popular.

[0003] Meanwhile, naked-eye 3D displays that give viewers a three-dimensional effect without wearing glasses or an HMD have also been proposed. Known 3D displays include a microlens array that changes the curvature of a liquid lens by placing droplets on the surface of a self-assembled monolayer (SAM) (see, for example, Patent Document 1), and a display panel with directional light-emitting elements as pixels (see, for example, Patent Document 2). A microlens array is also known that changes the optical properties of optical scatterers formed within an aperture by adjusting the voltage applied to an electrode with an aperture (see, for example, Patent Document 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 11-513129 [Patent Document 2] Patent No. 5767531 [Patent Document 3] Japanese Patent Application Publication No. 2019-120947 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 suggests a configuration in which 3D observation can be switched to two-dimensional (hereinafter referred to as "2D") observation by removing the lenses of the lens array, but does not disclose any specific means for removing the lenses of the lens array. Patent Document 2 eliminates the need for a lens array by using directional light-emitting elements for the pixels, but light-emitting elements with directivity in a predetermined direction are incorporated as pixels of the display panel, and switching between 3D and 2D display is not planned.

[0006] An object of the present invention is to provide a display device that can switch between 3D display and 2D display with a simple configuration. [Means for solving the problem]

[0007] In one aspect of the present invention, the display device comprises: The panel and a first microlens array disposed on the display surface side of the panel, the first microlens array having a first electrode in which a plurality of openings are formed, a transparent electrode facing the first electrode, and a dielectric transparent polymer material disposed between the first electrode and the transparent electrode; a second microlens array arranged on the light output side of the first microlens array and having an arrangement of a plurality of convex lenses; a control device for controlling application of a voltage to the first microlens array; Equipped with the first microlens array generates a concave lens at the aperture when a voltage is applied; The control device controls the voltage applied to the first microlens array to control the state of generation of the concave lenses, thereby switching between 3D display and 2D display. [Effects of the Invention]

[0008] A simple configuration allows you to switch between 3D and 2D display. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a display device according to an embodiment; [Figure 2] 10A and 10B are diagrams illustrating switching between 2D display and 3D display by controlling the applied voltage. [Figure 3] FIG. 10 is a diagram showing how the curvature of a concave lens is changed by controlling the applied voltage. [Figure 4] FIG. 2 is a diagram showing an example of the arrangement relationship between pixels of a panel and microlenses. [Figure 5] 5A and 5B are diagrams showing an example of an opening pattern formed in a first electrode. [Figure 6] FIG. 1 is a diagram illustrating a compound lens system of a concave lens and a convex lens. DETAILED DESCRIPTION OF THE INVENTION

[0010] 1 is a schematic diagram of a display device 1 according to an embodiment. The display device 1 includes a display 10 and an information processing device 50 connected to the display and configured to control switching between 3D display and 2D display.

[0011] The display 10 includes a panel 11, a first microlens array 20 arranged on the display surface 103 side of the panel 11, and a second microlens array 30 arranged on the light exit surface 203 side of the first microlens array 20. The first microlens array 20 is a variable-focus lens array with a variable focal length. The second microlens array 30 is a lens array in which the shape of each microlens, i.e., the focal length, is fixed, but the position of the second microlens array 30 is adjustable as needed.

[0012] The panel 11 is any medium for displaying images, such as electronic paper or signage (digital billboard), and may display either still images or moving images.

[0013] A plurality of openings 24 are formed in the first microlens array 20, and depending on whether the applied voltage is on or off, an array of concave lenses (described later) appears in the openings 24 on the light exit surface 203 side. The curvature of the formed concave lenses changes depending on the level of the applied voltage, thereby changing the focal length.

[0014] The second microlens array 30 has an array of multiple convex lenses 35 on the surface opposite to the first microlens array 20. Unlike the concave lenses of the first microlens array 20, the convex lenses 35 of the second microlens array 30 are fixed and designed to have a predetermined curvature and pitch.

[0015] The arrangement of the openings 24 of the first microlens array 20 corresponds to the arrangement of the convex lenses 35 of the second microlens array 30, and the opening diameters, numbers, arrangement positions, etc. are the same.

[0016] The position of at least one of the panel 11, the first microlens array 20, and the second microlens array may be controlled so that at least one of the distance between the panel 11 and the first microlens array 20 and the distance between the first microlens array 20 and the second microlens array is variable.

[0017] The information processing device 50 includes a user interface 51 and a control device 52. If the display 10 is incorporated into the display screen of the information processing device, the information processing device 50 may include a drive device 53.

[0018] The information processing device 50 incorporating the display 10 is any electronic device having a display screen and information processing functions, such as a personal computer (PC), a smartphone, a tablet terminal, an electronic book reader, an ATM, or a ticket machine.

[0019] The information processing device 50 does not necessarily have to be configured integrally with the display 10. For example, the information processing device 50 may be a remote controller that remotely operates the display 10. In this case, the drive device 53 may be incorporated into the display 10, and the information processing device 50 and the display 10 may have a wireless communication function.

[0020] The user interface 51 accepts command inputs from the user, including an instruction to switch between 2D display and 3D display, or an instruction to change the pop-out amount of a 3D image perceived by the viewer.

[0021] The control device 52 controls the on / off of the voltage applied to the first microlens array 20 to control the formation of the concave lenses in the openings 24, thereby switching between 3D and 2D display. It also controls the level of the voltage applied to the first microlens array 20 to control the formation state of the concave lenses and the amount of protrusion of the 3D image. The control device 52 is realized by a microprocessor with built-in memory, a logic device such as an FPGA (Field Programmable Gate Array), or the like. The drive device 53 may be, for example, a piezoelectric actuator.

[0022] 2 is a diagram illustrating switching between 2D display and 3D display by controlling the voltage applied to the first microlens array 20. (A) of FIG. 2 shows a state in which no voltage is applied (V=0), and (B) of FIG. 2 shows a state in which a voltage V1 is applied (V=V1).

[0023] The first microlens array 20 has a three-layer structure consisting of a first electrode 23 having an array of openings 24, a transparent electrode 21 facing the first electrode 23, and a dielectric polymer material 22 disposed between the first electrode 23 and the transparent electrode 21. The first microlens array 20 is disposed so that the transparent electrode 21 faces the panel 11 and the first electrode 23 faces the second microlens array 30.

[0024] The first electrode 23 and the transparent electrode 21 are connected to a variable voltage source 26. By controlling the on / off state of the voltage applied between the first electrode 23 and the transparent electrode 21 or the level of the applied voltage, it is possible to form light scatterers in the openings 24 by utilizing the electrostrictive properties of the dielectric polymer material 22. Each light scatterer formed in the openings 24 functions as a concave lens 25.

[0025] The concave lens 25 may be formed inside the opening 24, or a part of the concave lens 25 may protrude outside the opening 24. For example, the outer periphery of the lens may protrude from the opening 24, and the center of the lens may have a concave shape recessed below the outer periphery.

[0026] The polymer material 22 can be appropriately selected from materials that are transparent to visible light and have good voltage responsiveness, such as polyvinyl chloride (PVC), polymethylmethacrylate (PMMA), polyurethane, polystyrene, polyvinylacetate, polyvinylalchol, polycarbonate (PC), polyethylene terephthalate (PET), polyacrylonitrile (PAN), silicone elastomer, etc. In this embodiment, PVC is used because it deforms greatly under the action of an electric field and is easy to handle.

[0027] A plasticizer and / or an ionic liquid or an ionic surfactant may be added to the polymer material 22. The plasticizer provides flexibility to the polymer material 22. The ionic liquid or ionic surfactant promotes deformation of the polymer material 22 and can reduce the applied voltage.

[0028] The thickness of the polymer material 22 is determined appropriately depending on the size of the openings 24, the shape of the concave lenses to be formed, the thicknesses of the first electrode 23 and the transparent electrode 21, etc., but is, for example, 1 mm or less, preferably 0.1 mm to 0.5 mm. When producing a first microlens array 20 having a large number of minute concave lenses 25, the thickness of the polymer material 22 may be 0.1 mm or less.

[0029] The first electrode 23 is formed of an insulating material coated with a metal material or a conductive material. The openings 24 formed in the first electrode 23 have a size and shape that allows concave lenses 25 to be formed in the openings 24 when a voltage is applied. The planar shape of the openings 24 can be designed depending on the application of the lenses, such as circular, elliptical, oval, or rectangular. The size of the openings 24 allows the polymer material 22 to deform within the openings 24. When the planar shape of the openings 24 is circular, the diameter is 1 mm or less. When the planar shape of the openings 24 is elliptical or oval, the minor axis is 1 mm or less. When the planar shape of the openings 24 is rectangular, the width is 1 mm or less. The planar arrangement of the openings 24 can be freely set, such as a lattice arrangement or honeycomb arrangement. The quality of the displayed image depends on the amount of light entering through the lenses 25 formed in the openings 24. High image quality can be achieved by arranging the openings so that the aperture ratio, which represents the area occupied by the openings, is high. An aperture ratio of 50% or more is preferable.

[0030] The thickness of the second microlens array is not limited as long as the positions of all the convex lenses coincide with the positions of the apertures of the first microlens array. Also, as long as the convex lenses themselves are transparent, the other non-lens parts may be transparent or opaque.

[0031] The transparent electrode 21 may be formed from a transparent oxide semiconductor material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), or ZnO (Zinc Oxide), or a transparent conductive polymer may be used.

[0032] 2A, when no voltage is applied, the polymer material 22 of the first microlens array 20 does not deform, and light rays emitted from each pixel on the panel 11 pass through the first microlens array 20 as they are and enter the second microlens array 30. The incident light rays form a light spot via the convex lens 35 of the second microlens array 30 and enter the viewer's eye. The viewer perceives this as a 3D image. Note that a light spot is a point where multiple light rays converge and are recognized as a virtual light source, or in a broad sense, an image.

[0033] On the display 10, 3D display is performed when the voltage applied to the first microlens array 20 is turned off. The image displayed on the panel 11 is, for example, an image captured by a stereoscopic camera using a microlens array similar to the second microlens array 30.

[0034] 2B, when a voltage V1 is applied to the first microlens array 20, the polymer material 22 is deformed, and concave lenses 25 are formed in the openings 24 of the first electrode 23. The concave lenses 25 diffuse the light beams emitted from each pixel on the panel 11. The diffused light beams enter the second microlens array 30 and are refracted by the convex lenses 35 to be converted into parallel light. The viewer perceives the image displayed on the panel 11 as a 2D image.

[0035] 3 shows how the curvature of the concave lens 25 can be changed by controlling the applied voltage level. In FIG. 3A, when the voltage V applied to the first microlens array 20 is V1 (V=V1), the polymer material 22 deforms in response to the applied voltage, and a concave lens 25 is formed in the opening 24.

[0036] As an example, the transparent electrode 21 is the cathode, and the first electrode 23 having the opening 24 is the anode. Electrons are injected from the transparent electrode 21 into the polymer material 22, forming negatively charged species. The polymer material 22 containing the charged species bulges out of the opening 24 along the inner wall of the opening 24 in the first electrode 23, which is the anode, due to electrical creep deformation, and light scatterers are formed on the surface of the first electrode 23. On the other hand, the electric field distribution is lower in the center of the opening 24 than in the inner wall of the opening 24, so deformation of the polymer material 22 is small. As a result, a concave lens 25 with a relatively large curvature is formed in the opening 24.

[0037] The point where the light diffused by the concave lens 25 intersects with the optical axis OA when traced toward the light incident side is the focal point f1 of the concave lens 25 on the light incident side.

[0038] In Figure 3B, when a voltage V2 greater than V1 is applied, the deformation of the polymer material 22 becomes greater than in Figure 3A. Due to the elasticity of the polymer material 22, the polymer material 22 rises not only on the sides of the opening 24 but also near the center of the opening 24. The depression in the center of the opening 24 becomes shallower, the curvature becomes smaller, and the focal length becomes longer than in Figure 3A.

[0039] 3C, when a voltage V3 smaller than V1 is applied, the deformation of the polymer material 22 is smaller than that in FIG. 3A. Because the applied voltage is small, the deformation of the polymer material 22 is also small. The polymer material 22 is slightly pulled up along the sides of the opening 24, but the displacement of the polymer material 22 in the central region within the opening 24 is very small.

[0040] In this case, the curvature of the concave lens 25 is also reduced, and the focal length is longer than that in Fig. 3A. From the viewpoint of reducing power consumption, it is desirable to increase the focal length by reducing the applied voltage, as in Fig. 3C. The applied voltage, although depending on the thickness of the polymer material 22, is in the range of 100 to 1,000 V, and preferably 100 to 800 V.

[0041] The deformation of the polymer material 22 is reversible, and by applying a voltage, a concave lens 25 is formed that converts the light emitted from the convex lens 35 into nearly parallel light. Then, by turning off the voltage, the display can be restored to the 3D display shown in Figure 2(A).

[0042] 4 shows an example of the positional relationship between the pixels P of the panel 11 and the concave lenses 25. FIG. 4(A) shows an example in which a concave lens 25A having a circular planar shape is used. One concave lens 25A covers multiple pixels P. Each pixel P includes a color filter or a light-emitting element, such as red (R), green (G), or blue (B).

[0043] The number of pixels P covered by concave lens 25A is not limited to four, and aperture 24 can be designed to cover any number of pixels P. The color filter arrangement is not limited to the example in FIG. 3 and may be, for example, a Bayer array of RGGB.

[0044] 4B shows an example in which a concave lens 25B having a rectangular planar shape is used. One concave lens 25A covers four pixels P, but this is not limiting, and the aperture 24 can be designed to cover four pixels P.

[0045] The embodiment has the following specifications. (Display 10) -Type: LCD display Resolution: 750 x 1300 Pixel density: 330dpi (First microlens array 20) (1) First electrode 23 Aperture size: 150μm x 500μm Pitch: 50μm ·Opening ratio: 50% Thickness: 30μm (2) Polymer materials 22 Composition: PVC with 83% by weight of plasticizer dibutyl adipate Thickness: 0.3mm (3) Transparent electrode 21 Material: ITO film Thickness: 0.1mm ·Surface resistance: 30Ω / sq or less ·Light transmittance (wavelength 550nm): 85% or more (4) Lens characteristics Applied voltage: 300V ·Focal length (f1): 1.0mm (Second microlens array 30) Lens size: 150μm x 500μm Pitch: 50μm ·Focal length (f2): 0.5mm Distance from the first microlens array (d): 0.8 mm

[0046] 5 is an image of the opening pattern formed in the first electrode 23. The short sides of the openings 24 can be in the range of 10 to 500 μm, the long sides can be in the range of 500 to 2000 μm, and the pitch of the short sides can be in the range of 50 to 550 μm. The first electrode 23 is made of a metal such as stainless steel or aluminum, and has a thickness of 10 to 100 μm.

[0047] 6 is a diagram illustrating a compound lens system consisting of a concave lens 25 and a convex lens 35. The concave lens 25 is a variable-focus lens formed in the first microlens array 20 in response to a voltage. The convex lens 35 is a second-focus lens formed in the second microlens array 30. The distance between the centers of the concave lens 25 and the convex lens 35 is d.

[0048] On the optical axis OA, f1 is the focal point of the concave lens 25, f2 is the focal point of the convex lens 35, and S1 and S2 are the principal surfaces of the compound lens. The principal points S1 and S2 are the points where the principal surfaces P1 and P2 of the compound lens intersect perpendicularly with the optical axis OA.

[0049] The distance from an object (e.g., an image) A1B1 on panel 11 to concave lens 25 is a1, and the distance from concave lens 25 to imaginary light source A2B2 is b1. The distance from imaginary light source A2B2 to convex lens 35 is a2, and the distance from convex lens 35 to real image A3B3 formed by the compound lens is b2.

[0050] Among the light rays emitted from object A1B1, ray (i) parallel to the optical axis OA is refracted by concave lens 25 and travels in a direction with the focus f1 in front of the lens as a virtual light source, and is then refracted by convex lens 35 in a direction toward the optical axis OA.

[0051] The light ray (ii) passing through the center of the concave lens 25 travels straight ahead and is refracted by the convex lens 35 in a direction toward the optical axis OA.

[0052] A ray (iii) heading toward a focal point f1 behind the lens passes through the concave lens 25, travels parallel to the optical axis OA, is refracted by the convex lens 35, and passes through a focal point f2 behind the convex lens 35.

[0053] A ray (iv) that is incident on the convex lens 35 at the same position as the ray that passes through the front focal point f2 of the convex lens 35 passes through the convex lens 35 and then travels parallel to the optical axis OA.

[0054] The compound lens forms a real image A3B3 at the intersection of rays (i) to (iv). The point where ray (iv) intersects with the optical axis OA in front of the compound lens is the front focus of the compound lens (labeled "left focal position" in the figure). The distance from the principal point S1 of the compound lens to the front focus is the focal length f of the compound lens.

[0055] The point where ray (i) intersects with the optical axis OA behind the compound lens is the back focus of the compound lens (labeled "right focus position" in the diagram). Similarly, the distance from the principal point S2 of the compound lens to the back focus is the focal length f of the compound lens.

[0056] The distance σ1 from the concave lens 25 to the principal point S1 of the compound lens is (f×d) / f2. The distance σ2 from the convex lens 35 to the principal point S2 of the compound lens is (f×d) / f1. When f1 is infinite, it corresponds to the initial state of Figure 2(A).

[0057] 5, the display can be changed to 2D by combining the first microlens array 20 and the second microlens array 30 and determining the voltage conditions to be applied to the first microlens array 20. When performing 2D display, the original image data supplied to the panel 11 may be controlled to be upside down.

[0058] In this way, it is possible to switch between 2D and 3D display by controlling the on / off of the voltage applied to the first microlens array 20. In addition, it is possible to change the amount of protrusion of the 3D image perceived by the viewer by controlling the level of the applied voltage. [Explanation of symbols]

[0059] 1 Display device 10 Display 11 Panels 20 First microlens array 21 Transparent electrode 22 Polymer materials 23 1st electrode 24 Aperture 25, 25A, 25B concave lenses 30 Second microlens array 35 Convex Lens 50 Information processing equipment 51 User Interface 52 Control device 53 Drive unit 103 Display surface 203 Light exit surface P pixel

Claims

1. The panel and a first microlens array disposed on the display surface side of the panel, the first microlens array having a first electrode having a plurality of openings formed therein, a transparent electrode facing the first electrode, and a dielectric transparent polymer material disposed between the first electrode and the transparent electrode; a second microlens array disposed on the light exit side of the first microlens array and having an arrangement of a plurality of convex lenses; a control device for controlling application of a voltage to the first microlens array; a driving device connected to the first microlens array and the second microlens array; Equipped with the first microlens array generates a concave lens at the aperture when a voltage is applied; the control device controls the voltage applied to the first microlens array to control a generation state of the concave lenses, thereby switching between a three-dimensional display and a two-dimensional display; The display device is characterized in that the driving device drives at least one of the first microlens array and the second microlens array in accordance with the voltage applied to the first microlens array under the control of the control device, thereby adjusting the positional relationship between the first microlens array and the second microlens array.

2. 2. The display device according to claim 1, wherein the control device performs three-dimensional display by turning off the application of the voltage to the first microlens array, and performs two-dimensional display by turning on the application of the voltage.

3. 3. The display device according to claim 1, wherein the control device adjusts the voltage applied to the first microlens array to change the focal length of the first microlens array and thereby change the amount of protrusion of the three-dimensional display.

4. 4. The display device according to claim 3, wherein the control device increases the focal length of the concave lens by increasing the level of the voltage applied to the first microlens array, and decreases the focal length of the concave lens by decreasing the level of the voltage applied to the first microlens array.

5. a first microlens array and a second microlens array are arranged in this order on the display surface side of the panel, the first microlens array being formed of a first electrode having a plurality of openings formed therein, a transparent electrode facing the first electrode, and a dielectric transparent polymer material being arranged between the first electrode and the transparent electrode, and the second microlens array has an arrangement of a plurality of convex lenses; controlling a voltage applied to the first microlens array to control generation of a concave lens in the aperture, thereby switching between a three-dimensional display and a two-dimensional display; driving at least one of the first microlens array and the second microlens array in accordance with the voltage applied to the first microlens array, thereby adjusting the positional relationship between the first microlens array and the second microlens array; A display method characterized by:

6. By turning on the application of the voltage, an image on the panel is displayed in two dimensions; 6. The display method according to claim 5, wherein an image is displayed three-dimensionally in a space on the exit side of the second microlens array by turning off the application of the voltage.

7. The display method according to claim 5 or 6, characterized in that the level of the voltage applied to the first microlens array is adjusted to change the focal length of the concave lens and thereby change the amount of protrusion of the three-dimensional display from the second microlens array.

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