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 having a plurality of arrangements of pixels and displaying an image; a micro lens array arranged on a display surface side of the panel, the micro lens array having a first electrode with a plurality of openings, a transparent electrode facing the first electrode, and a dielectric high-polymer material located between the first electrode and the transparent electrode; and a controller for controlling application of voltages on the micro lens array. The controller controls generation of a micro lens in the openings by controlling a voltage applied on the micro lens array, and thus switches a display between a three-dimensional display and a second-dimensional display.SELECTED DRAWING: Figure 1

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 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, etc. A 3D image is an image in which an object appears three-dimensional to the observer, or an image in which an object appears to pop out or has a sense of depth. In addition to the traditional glasses-based 3D display, head-mounted displays (HMDs) that display virtual reality content in three dimensions are also becoming widespread.

[0003] On the other hand, naked-eye 3D display has also been proposed, which gives a three-dimensional effect to the viewer with the naked eye without wearing glasses or an HMD. 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 configuration that displays 3D images without the need for a lens array by forming a display panel with directional light-emitting elements as pixels (see, for example, Patent Document 2). A microlens array that adjusts the optical properties of an optical scatterer formed in an aperture by adjusting the voltage applied to an electrode having an aperture is known (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] JP 2019-120947 A 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 a specific means for removing the lenses of the lens array. Patent Document 2 incorporates light-emitting elements having directivity in a predetermined direction as pixels of a display panel, and does not anticipate switching between 3D and 2D display.

[0006] An object of the present invention is to provide a display device capable of switching 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: A panel having an array of a plurality of pixels and displaying an image; a microlens array disposed on a display surface side of the panel, the microlens array having a first electrode having a plurality of openings formed therein, a transparent electrode facing the first electrode, and a dielectric polymer material disposed between the first electrode and the transparent electrode; A control device for controlling application of a voltage to the microlens array; Equipped with The controller controls the voltage applied to the microlens array to control the generation of microlenses at the aperture, thereby switching between 3D and 2D display. Effect of the Invention

[0008] It is possible to switch between 3D and 2D display with a simple configuration. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a display according to an embodiment and a display device using the display; [Diagram 2]1A to 1C are diagrams illustrating switching between 2D display and 3D display by controlling an applied voltage. [Diagram 3] FIG. 11 is another diagram illustrating switching between 2D display and 3D display by controlling the applied voltage. [Figure 4] FIG. 1 is a diagram illustrating the principle of 3D image generation. [Diagram 5] 1 is a diagram showing an example of the arrangement relationship between pixels of a panel and microlenses; [Figure 6] 11A and 11B are diagrams illustrating changes in a periodic pattern caused by a microlens. [Figure 7] 1 shows a pattern of openings formed in a first electrode. [Figure 8] FIG. 13 is a diagram showing a moire fluctuation caused by turning on a voltage. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Fig. 1(A) is a schematic diagram of a display 10 according to an embodiment, and Fig. 1(B) is a schematic diagram of a display device 1 using the display 10. The display 10 has a panel 11 and a variable-focus microlens array 20 arranged on the display surface 103 side of the panel 11. The distance d between the panel 11 and the microlens array 20 may be fixed, but is desirably variable as described below.

[0011] Panel 11 is any medium for displaying images, such as electronic paper or signage, and the displayed image may be a still image or a moving image. Microlens array 20 has a three-layer structure including a first electrode 23 having an array of openings 24, a transparent electrode 21 facing first electrode 23, and a dielectric polymer material 22 disposed between first electrode 23 and transparent electrode 21. Microlens array 20 is disposed such that transparent electrode 21 faces panel 11.

[0012] The first electrode 23 and the transparent electrode 21 are connected to a variable voltage source 26. By controlling the on / off of the voltage applied between the first electrode 23 and the transparent electrode 21, or the level of the applied voltage, a light scatterer can be formed inside the opening 24 by utilizing the voltage responsiveness or elasticity of the dielectric polymer material 22. Each light scatterer formed in the opening 24 functions as a microlens 25.

[0013] 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), polyethylenetelephtalate (PET), polyacrylonitrile (PAN), silicone elastomer, etc. In the embodiment, PVC is used, which is easily handled and deforms greatly under the action of an electric field.

[0014] 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 the ionic surfactant promotes deformation of the polymer material 22 and can reduce the applied voltage. The polymer material 22 may be dissolved in a suitable solvent.

[0015] The thickness of the polymer material 22 is determined appropriately depending on the size of the opening 24, the height of the microlens 25 to be formed, the thickness of the first electrode 23 and the transparent electrode 21, etc., and is, for example, 1 mm or less, preferably 0.1 mm to 0.5 mm. However, when producing a microlens array 20 having a large number of fine microlenses 25, the thickness of the polymer material 22 may be 0.1 mm or less.

[0016] The first electrode 23 is an insulator coated with a conductive metal or conductive material. The opening 24 formed in the first electrode 23 has a size and shape that allows a microlens 25 to be formed in the opening 24 when a voltage is applied. The planar shape of the opening 24 can be designed according to the use of the lens, such as a circle, an ellipse, an oval, or a rectangle. The size of the opening 24 is a size that allows the polymer material 22 to deform within the opening 24 and is an integer multiple of the pixel size of the panel 11. When the planar shape of the opening 24 is a circle, the diameter is 1 mm or less. When the planar shape of the opening 24 is an ellipse or an oval, the short diameter is 1 mm or less, and when the planar shape of the opening 24 is a rectangle, the width is 1 mm or less. The planar arrangement of the openings 24 can be freely set, such as a lattice arrangement or a honeycomb arrangement. The brightness of the displayed image depends on the amount of light entering through the lens 25 formed in the opening 24, and high image quality can be obtained by arranging the openings so that the aperture ratio, which represents the area occupied by the openings, is high. The aperture ratio is preferably 50% or more.

[0017] The transparent electrode 21 may be formed of a transparent oxide semiconductor material such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), ZnO (Zinc Oxide), or the like, or a transparent conductive polymer may be used.

[0018] In (B) of Fig. 1, the display device 1 has a display 10 and a control device 52 that controls a voltage applied to the microlens array 20 of the display 10. In the example of (B) of Fig. 1, the display 10 is applied to a display screen of an information processing device 50. The information processing device 50 may be an electronic device having a display screen and an information processing function, such as a personal computer (PC), a smartphone, a tablet terminal, an e-book reader, an ATM, or a ticket machine, or may be a remote controller that remotely operates the display 10.

[0019] The information processing device 50 may have a user interface 51 and a driving device 53 in addition to the control device 52. The driving device 53 is connected to the display 10 and changes the distance d between the panel 11 and the microlens array 20 under the control of the control device 52. As the driving device, for example, a piezoelectric actuator may be used.

[0020] The user interface 51 accepts command inputs from a user. Command inputs include an instruction to switch between 2D display and 3D display, change the pop-out amount of a 3D image, etc. When the information processing device 50 is configured as a remote controller, the driving device 53 may be incorporated in the display 10, and the information processing device 50 and the display 10 may have a wireless communication function.

[0021] In (B) of Fig. 1, light rays output from the entire microlens array 20 form a light spot at position 30, which enters the observer's eye and allows the observer to view a 3D image. Note that a light spot is a point that is recognized as a virtual light source or, in a broad sense, an image, formed by the convergence of multiple light rays.

[0022] Figure 2 is a diagram explaining the switching between 2D display and 3D display by controlling the applied voltage. Figure 2(A) shows the state when the applied voltage V is zero (V=0), Figure 2(B) shows the state when the applied voltage V is V1 (V=V1), and Figure 2(C) shows the state when the applied voltage V is V2, which is greater than V1 (V=V2, V2>V1).

[0023] An image is displayed on the panel 11. There are no particular limitations on the image displayed on the panel 11, and it may be a normal 2D image, a 3D image captured by a stereoscopic camera using a microlens array, or the like.

[0024] In FIG. 2A, when no voltage is applied, the polymer material 22 of the microlens array 20 does not deform, the image on the panel 11 passes through the microlens array 20 as is, and the viewer sees a 2D image on the display 10.

[0025] 2B, when a voltage V1 is applied to the microlens array 20, the polymer material 22 deforms to form microlenses 25 within the openings 24 of the first electrode 23. Each microlens 25 projects the image on the panel 11 into a 3D image in a space including the display 10.

[0026] 2C, when a voltage V2 greater than V1 is applied to the microlens array 20, the amount of deformation of the polymer material 22 increases, and the curvature of each microlens 25 increases. Since the focal length changes due to the change in the curvature of the microlens 25, it is possible to change the projection distance of the 3D image from the display 10, thereby expressing a sense of depth.

[0027] The voltage applied to the microlens array 20 is equal to or less than 1,000 V. The focal length of the microlens 25 depends on the lens diameter, that is, the diameter of the opening 24, but is in the range of 0.1 mm to 10 mm.

[0028] As an example, when 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 protrudes from the opening 24 of the first electrode 23. With the addition of the elasticity of the polymer material 22, the polymer material 22 protrudes from the minute opening 24 to the outside of the opening via the inner wall of the opening 24, and a microlens 25 is formed on the surface of the first electrode 23. If the composition of the polymer material 22 is uniform, microlenses 25 with little variation can be formed by applying the same level of voltage.

[0029] The deformation of the polymer material 22 is reversible, and it can be returned to the initial state (image) of Fig. 2(A) by reducing the applied voltage. In addition, the focal length can be increased as shown in Fig. 2(B).

[0030] The microlenses 25 have a small diameter and are transparent, so that the display quality is high. In addition, the focal length can be adjusted over a wide range, particularly up to a short focal length, so that the viewing angle is wide.

[0031] Fig. 3 is a diagram for explaining another example of switching between 2D display and 3D display by controlling the applied voltage. In Fig. 3, the distance d between the panel 11 and the microlens array 20 is changed according to the formation state of the microlens 25. The distance d represents the focal length of the formed microlens array 20, and is defined as the distance between the principal point, which is determined by the refractive index of the polymer and the radius of curvature of the lens, and the focal point of the microlens 25.

[0032] 3A, in a state where no voltage is applied (V=0), the panel 11 and the microlens array 20 may be close to each other, or may be in contact with each other. As described with reference to FIG. 2A, the image on the panel 11 passes through the microlens array 20 as is, and the viewer sees the image on the display 10.

[0033] 3B, when a voltage V1 is applied to the microlens array 20 and a microlens 25 is formed in the opening 24 of the first electrode 23, the distance d between the panel 11 and the microlens array 20 is set to d1. d1 indicates the focal length of the microlens array 20. A light ray output from each microlens 25 forms a light spot at a position 30 in the space of the display 10, and the observer views a 3D image.

[0034] In FIG. 3C, when a voltage V2 larger than V1 is applied to the microlens array 20, the deformation of the polymer material 22 increases, and the curvature of each microlens 25 increases. The change in the curvature of the microlens 25 shortens the focal length. In this case, the distance d between the panel 11 and the microlens array 20 is reduced. The position 30 of the light spot is closer to the display 10 than in FIG. 3B.

[0035] Even if the distance d between the panel 11 and the microlens array 20 is fixed, the observer can see a 3D image by forming the microlenses 25 on the surface of the first electrode 23, but the 3D image may become blurred depending on the projection distance. In this case, it is desirable to change the distance d in accordance with the focal length of the microlenses 25. At least one of the panel 11 and the microlens array 20 may be driven in response to an applied voltage by a driving device 53 incorporated in the information processing device 50 or the display 10.

[0036] Fig. 4 is a diagram for explaining the principle of 3D image generation. Fig. 4(A) shows a state in which the microlenses 25 formed in the microlens array 20 have a large curvature and a short focal length. Fig. 4(B) shows a state in which the microlenses 25 formed in the microlens array 20 have a small curvature and a long focal length. As described above, the polymer material 22 is reversibly deformed, and can transition from state (A) to state (B) by reducing the voltage applied to the microlens array 20.

[0037] A 3D image is formed at a position 30 where light rays from pixels 101 of panel 11 intersect by microlens array 20. The focal length f of microlens 25 changes in response to a change in the applied voltage.

[0038] A change in focal length f changes the position of the plane and the observer perceives the 3D image position 30 as having changed in space.

[0039] FIG. 5 shows an example of the arrangement relationship between the pixels 101 of the panel 11 and the microlenses 25. FIG. 5A shows an example in which a circular microlens 25A is used. One microlens 25A covers a plurality of pixels 101. For example, each pixel 101 includes a color filter or a light-emitting element in a three-color arrangement of red (R), green (G), and blue (B). The number of pixels 101 covered by the microlens 25A is not limited to four, and the microlens 25A can be designed to cover the pixels 101. The color filter arrangement is not limited to the example of FIG. 5, and may be, for example, a Bayer arrangement of RGGB.

[0040] 5B shows an example in which a rectangular microlens 25B is used. One microlens 25A covers four pixels 101, but this is not limiting and the microlens 25B can be designed to cover all four pixels 101.

[0041] The embodiment has the following specifications. (Display 10) -Type: LCD display Resolution: 750 x 1300 -Pixel density: 330dpi (Microlens Array 20) (1) First electrode 23 Aperture size: 150μm×500μm Pitch: 50μm ·Opening ratio: 50% Thickness: 30μm (2) Polymer materials 22 Composition: PVC with 83wt% dibutyl adipate plasticizer Thickness: 0.2mm (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: 500V ·Focal length: 0.4mm

[0042] 6 is a diagram showing the change in the periodic pattern (width 500 μm) caused by rectangular microlenses 25B. In the lens area, rectangular microlenses 25B formed by applying a voltage are regularly arranged. The microlens array is installed at a position 0.4 mm away from the display device.

[0043] In the area without lenses, the pixel arrangement passes directly through the laminate of the transparent electrode 21, the polymer material 22, and the first electrode 23, generating moire, which is clearly different from the periodic pattern in the lens area. Figure 6 confirms the manifestation of the lens function in the microlens array 20.

[0044] 7 is an image of the pattern of the openings 24 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 2,000 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.

[0045] As shown in Fig. 8, it was confirmed that the moire fluctuates when the voltage is turned on, and a periodic arrangement of the microlenses 25 is formed. This indicates that the microlenses function as lenses and that an image of the display device can be formed on the microlenses.

[0046] The display device 1 of the embodiment does not require any wearing accessories such as glasses or HMD, and enables the user to observe 3D images with the naked eye without putting a burden on the user. In addition, it is possible to switch between displaying 3D images and 2D images, and it is possible to control the pop-out amount of the 3D image.

[0047] The microlens array 20 is made of two electrode layers and a transparent dielectric polymer material placed between these electrode layers, and can switch between 3D and 2D display simply by turning on and off the application of voltage. Also, the amount of protrusion of the 3D image can be changed simply by changing the level of the applied voltage.

[0048] In the microlens array 20 of the embodiment, the lens diameter of each microlens 25 is small and the microlens array 20 has high transparency, so that high image quality is achieved whether a 2D image or a 3D image is displayed. [Explanation of symbols]

[0049] 1 Display device 10. Display Panel 11 20 Microlens Array 21 Transparent electrode 22 Polymer materials 23 1st electrode 24 Aperture 25, 25A, 25B Micro Lenses 50 Information processing device 51 User Interface 52 Control device 53 Drive unit 101 pixels 103 Display surface

Claims

1. A panel having an array of a plurality of pixels and displaying an image; a microlens array disposed on a display surface side of the panel, the microlens array having a first electrode having a plurality of openings formed therein, a transparent electrode facing the first electrode, and a dielectric polymer material disposed between the first electrode and the transparent electrode; A control device for controlling application of a voltage to the microlens array; a driving device connected to at least one of the panel and the microlens array; Equipped with the control device controls a voltage applied to the microlens array to control generation of the microlenses at the aperture, 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 panel and the microlens array in accordance with the voltage applied to the microlens array under the control of the control device, so that when the focal length of the microlens array is a first distance, the distance between the panel and the microlens array is changed to be shorter than when the focal length of the microlens array is a second distance longer than the first distance.

2. The display device according to claim 1, characterized in that the control device displays the image in two dimensions by turning off the application of the voltage, and displays the image in three dimensions in the space on the exit side of the microlens array by turning on the application of the voltage.

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

4. The display device described in claim 3, characterized in that the control device reduces the amount of protrusion of the three-dimensional display by increasing the voltage applied to the microlens array, and increases the amount of protrusion of the three-dimensional display by decreasing the voltage applied to the microlens array.

5. a first electrode having a plurality of openings formed therein, a transparent electrode facing the first electrode, and a microlens array made of a dielectric transparent polymer material and disposed between the first electrode and the transparent electrode, on a display surface side of a panel having a pixel array and displaying an image; switching between a three-dimensional display and a two-dimensional display by controlling a voltage applied to the microlens array to control generation of the microlenses at the aperture; at least one of the panel and the microlens array is driven in response to the voltage applied to the microlens array, and when the focal length of the microlens array is a first distance, the distance between the panel and the microlens array is changed to be shorter than when the focal length of the microlens array is a second distance longer than the first distance; A display method comprising:

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

7. The display method according to claim 5 or 6, characterized in that the focal length of the microlens array is changed by adjusting the level of the voltage applied to the microlens array, thereby changing the amount by which the three-dimensional display protrudes from the microlens array.

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