Electrochromic element and display device

Abstract

To provide an electrochromic element which can reduce the time required to switch a light shielding state to a light transmission state, and a display device using the electrochromic element.SOLUTION: The electrochromic element includes: a first electrode having a first conductive region and a first non-conductive region and connected to a first potential; a second electrode facing the first electrode, the second electrode having a second conductive region in a ratio higher than the ratio of the first conductive region in the first electrode; and an electrolyte layer between the first electrode and the second electrode, the electrolyte layer including an electrochromic material.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electrochromic element and a display device having the same. [Background technology]

[0002] An electrochromic element has, for example, an electrolyte layer containing an electrochromic material such as silver (Ag) between a pair of electrodes (for example, Patent Documents 1 and 2). In this electrochromic element, a light-shielding state and a light-transmitting state can be switched by controlling the voltage applied between the pair of electrodes.

[0003] For example, when switching from a light-transmitting state to a light-blocking state, silver ions in the electrolyte layer are reduced and silver precipitates on the electrode surface, and when switching from a light-blocking state to a light-transmitting state, the silver precipitated on the electrode surface dissolves in the electrolyte layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-148825 A [Patent Document 2] JP 2018-72490 A Summary of the Invention [Problem to be solved by the invention]

[0005] In such an electrochromic element, the time required to switch from a light-shielding state to a light-transmitting state tends to be longer than the time required to switch from a light-transmitting state to a light-shielding state.

[0006] The present invention has been made in consideration of the above circumstances, and has an object to provide an electrochromic element capable of shortening the time required to switch from a light-shielding state to a light-transmitting state, and a display device using the same. That is, an object of the present invention is to provide an electrochromic element capable of shortening the time required to switch from a light-shielding state to a light-transmitting state, and a display device using the same. [Means for solving the problem]

[0007] The above object can be achieved by the following means.

[0008] (1) An electrochromic element comprising: a first electrode having a first conductive region and a first non-conductive region and connected to a first potential; a second electrode facing the first electrode and having a second conductive region with a proportion of the second conductive region greater than the proportion of the first conductive region in the first electrode; and an electrolyte layer provided between the first electrode and the second electrode and containing an electrochromic material.

[0009] (2) The electrochromic element according to (1) above, wherein the second electrode further has a second non-conductive region and is connected to a second potential.

[0010] (3) The electrochromic element according to (1) above, wherein the first electrode has a plurality of the first non-conductive regions.

[0011] (4) The electrochromic element according to (3) above, wherein the first non-conductive regions are arranged in a predetermined pattern.

[0012] (5) The electrochromic element according to (4) above, wherein the plurality of first non-conductive regions each have a rectangular planar shape.

[0013] (6) The electrochromic element according to (1) above, wherein the first electrode includes a first transparent conductive film, and the second electrode includes a second transparent conductive film.

[0014] (7) An electrochromic element according to (6) above, wherein the first electrode further includes an insulating film provided between the first transparent conductive film and the electrolyte layer and selectively disposed in the first non-conductive region.

[0015] (8) The electrochromic element according to (6) above, wherein the first transparent conductive film has an opening selectively provided in the first non-conductive region.

[0016] (9) The electrochromic element according to (6) above, wherein the first electrode is laminated on the first transparent conductive film and further includes a first low resistance conductive film having a lower resistivity than the first transparent conductive film.

[0017] (10) The electrochromic element according to (9) above, wherein the first low-resistance conductive film is provided on at least a portion of the first conductive region.

[0018] (11) An electrochromic element as described in (9) above, wherein the second electrode is laminated on the second transparent conductive film and further includes a second low resistance conductive film having a lower resistivity than the second transparent conductive film, and at least a portion of the second low resistance conductive film is disposed in a position facing the first low resistance conductive film.

[0019] (12) The electrochromic element according to (6) above, wherein at least one of the first transparent conductive film and the second transparent conductive film is a solid film.

[0020] (13) The electrochromic element according to (1) above, which can be in a light-shielding state in which the electrochromic material is deposited on the surface of the second electrode, and in a light-transmitting state in which the electrochromic material is dissolved in the electrolyte layer.

[0021] (14) The electrochromic element according to (13) above, further comprising a voltage application section that applies a voltage between the first electrode and the second electrode to switch between the light blocking state and the light transmitting state.

[0022] (15) The electrochromic element according to (14) above, wherein the voltage application unit applies, when switching from the light-shielding state to the transmitting state, a voltage that is substantially the same magnitude as the voltage applied when switching from the transmitting state to the light-shielding state.

[0023] (16) An electrochromic element according to (1) above; and a transparent display laminated on the electrochromic element and having a light-transmitting region and a light-opaque region. A display device comprising:

[0024] (17) The display device according to (16), wherein at least a portion of the first conductive region is disposed in a position overlapping the light-opaque region. Effect of the Invention

[0025] In the electrochromic element and display device according to the present invention, the first electrode has a first non-conductive region. This allows the first non-conductive region to maintain light transparency even if a relatively large voltage is applied between the first and second electrodes when switching from a light-blocking state to a light-transmitting state. This makes it possible to shorten the time required to switch from the light-blocking state to the light-transmitting state. [Brief description of the drawings]

[0026] [Figure 1] 1 is a cross-sectional view illustrating a schematic configuration of a display device according to an embodiment of the present invention. [Diagram 2] 2 is a diagram illustrating an example of a planar configuration of a first electrode illustrated in FIG. 1. [Diagram 3] 3 is a diagram illustrating another example of the planar configuration of the first electrode illustrated in FIG. 2. [Figure 4] 2 is a diagram illustrating an example of a planar configuration of the transparent display illustrated in FIG. 1. [Figure 5A] 2 is a cross-sectional view illustrating an example of the electrochromic element illustrated in FIG. 1 in a non-voltage-applied state. [Figure 5B] 2 is a cross-sectional view illustrating an example of the electrochromic element illustrated in FIG. 1 in a light-shielded state. [Figure 5C] 2 is a cross-sectional view illustrating an example of a light transmitting state of the electrochromic element illustrated in FIG. 1. [Figure 6] FIG. 2 is a diagram illustrating an example of a voltage applied to the electrochromic element shown in FIG. [Figure 7] 2 is a diagram illustrating an example of a change in light transmittance of the electrochromic element shown in FIG. [Figure 8] FIG. 1 is a cross-sectional view illustrating an example of the configuration of an electrochromic element according to a comparative example. [Figure 9] FIG. 9 is a diagram illustrating an example of a voltage applied to the electrochromic element shown in FIG. [Figure 10] 1 is a cross-sectional view illustrating an example of the configuration of an electrochromic element according to Modification 1. FIG. [Figure 11] 11 is a diagram illustrating an example of a planar configuration of a second electrode illustrated in FIG. 10. FIG. [Figure 12] 12 is a diagram illustrating another example of the planar configuration of the second electrode illustrated in FIG. 11. [Figure 13] FIG. 11 is a cross-sectional view illustrating an example of the configuration of an electrochromic element according to Modification 2. [Figure 14] 14 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 13. [Figure 15] 14 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 13. [Figure 16] FIG. 11 is a cross-sectional view illustrating an example of the configuration of an electrochromic element according to Modification 3. [Figure 17] 17 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 16. [Figure 18] 17 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 16. [Figure 19] 17 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 16. [Figure 20] 17 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 16. [Figure 21]17 is a cross-sectional view illustrating another example of the configuration of the electrochromic element shown in FIG. 16. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, the embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following drawings, the same reference numerals refer to the same components, and the size of each component in the drawings may be exaggerated for clarity and convenience of description. Meanwhile, the embodiments described below are merely examples, and various modifications are possible from such embodiments.

[0028] In the following description, the terms "upper" and "above" may include not only something that is directly above in contact with something, but also something that is above without contacting something.

[0029] The singular expression includes the plural expression unless the context clearly indicates otherwise. In addition, when a part is described as "comprising" or "having" a certain element, it does not mean excluding other elements, but means that other elements may be further included, unless otherwise specified to the contrary.

[0030] Additionally, use of the terms "said" and similar referents refers to both the singular and the plural.

[0031] Unless the steps constituting the method are explicitly described in order or described to the contrary, the steps may be performed in any suitable order, and the order of the steps described is not necessarily limited to the order of the steps described. The use of any examples or exemplary terms (such as, for example, etc.) is merely for the purpose of illustrating the technical idea, and the scope of the invention is not limited by the examples or exemplary terms, except as limited by the scope of the claims.

[0032] <Embodiment> (Configuration of display device 100) Fig. 1 shows an example of the configuration of a display device (display device 100) according to one embodiment of the present invention. Fig. 1 shows a cross-sectional configuration of the display device 100. This display device 100 has an electrochromic element 1 and a transparent display 2. The transparent display 2 is laminated on the electrochromic element 1.

[0033] The electrochromic element 1 has, for example, a first substrate 10, a first electrode 20, an electrolyte layer 30, a second electrode 40, and a second substrate 50 in this order from the transparent display 2 side. The electrolyte layer 30 contains an electrochromic material. The electrochromic element 1 further has a sealant 60 and a voltage application unit 70. The sealant 60 serves to seal the electrolyte layer 30 between the first substrate 10 and the second substrate 50. The voltage application unit 70 applies a voltage between the first electrode 20 and the second electrode 40.

[0034] This electrochromic element 1 can take a light-shielding state and a light-transmitting state (for example, a light-shielding state S1 in FIG. 5B and a light-transmitting state S2 in FIG. 5C described below) by controlling the voltage applied between the first electrode 20 and the second electrode 40. The light-shielding state and the light-transmitting state are configured to be mutually switchable. For example, when switching from the light-transmitting state to the light-shielding state, the electrochromic material dissolved in the electrolyte layer 30 precipitates on the surface of the second electrode 40. For example, when switching from the light-shielding state to the light-transmitting state, the electrochromic material precipitated on the surface of the second electrode 40 dissolves in the electrolyte layer 30.

[0035] The transparent display 2 has, for example, a transparent substrate 80, a driving substrate 91, and a light-emitting element 92 in this order from the electrochromic element 1 side. The transparent display 2 has a plurality of driving substrates 91 and a plurality of light-emitting elements 92. The light-emitting elements 92 include, for example, a red light-emitting element 92R, a green light-emitting element 92G, and a blue light-emitting element 92B, and the red light-emitting element 92R, the green light-emitting element 92G, and the blue light-emitting element 92B are provided on each of the plurality of driving substrates 91. For example, the red light-emitting element 92R, the green light-emitting element 92G, and the blue light-emitting element 92B are arranged in this order along a predetermined direction. In the display device 100, an image is displayed on the transparent display 2 side.

[0036] In the following description, the stacking direction of the electrochromic element 1 and the transparent display 2 is sometimes referred to as the Z direction, the arrangement direction of the red light-emitting element 92R, the green light-emitting element 92G, and the blue light-emitting element 92B is sometimes referred to as the X direction, and the direction perpendicular to the X direction and the Z direction is sometimes referred to as the Y direction.

[0037] (Configuration of electrochromic element 1) The first substrate 10 and the second substrate 50 are provided, for example, facing each other in the Z direction. The first substrate 10 and the second substrate 50 are, for example, transparent substrates having translucency. The first substrate 10 and the second substrate 50 are, for example, made of glass or resin. The materials constituting the first substrate 10 and the second substrate 50 may be different from each other. The first substrate 10 and the second substrate 50 have, for example, a quadrangular planar (XY plane) shape. The sizes of the XY plane of the first substrate 10 and the second substrate 50 are, for example, approximately the same.

[0038] A first electrode 20 is provided on the surface of the first substrate 10 that faces the second substrate 50. Hereinafter, the surface of the first substrate 10 that faces the second substrate 50 may also be referred to as the lower surface of the first substrate 10. The first electrode 20 is provided, for example, in contact with the lower surface of the first substrate 10. The electrochromic element 1 has a single first electrode 20 that is connected to a first potential. The first electrode 20 has, for example, a transparent conductive film 21 (first transparent conductive film) that is translucent. The transparent conductive film 21 may be made of, for example, ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), SnO 2 and ZnO. The first electrode 20 includes a single transparent conductive film 21 that is not electrically divided. The transparent conductive film 21 may have a laminated structure.

[0039] In this embodiment, the first electrode 20 has a non-conductive region 20N (first non-conductive region). The non-conductive region 20N is a region that does not have substantial conductivity. Although the details will be described later, this suppresses deposition of the electrochromic material in the non-conductive region 20N even if a relatively large voltage is applied between the first electrode 20 and the second electrode 40 when switching the electrochromic element 1 from a light-shielding state to a light-transmitting state. Therefore, at least the non-conductive region 20N maintains light transparency. The region of the first electrode 20 other than the non-conductive region 20N is a conductive region 20C (first conductive region).

[0040] The non-conductive region 20N is formed of, for example, an opening 21M provided in the transparent conductive film 21. In other words, the opening 21M is selectively provided in the non-conductive region 20N. The first electrode 20 has, for example, a plurality of non-conductive regions 20N (openings 21M), and the plurality of non-conductive regions 20N are arranged in a dispersed manner. For example, in the electrochromic element 1, a plurality of openings 21M are formed in a predetermined pattern in a single transparent conductive film 21 provided on the lower surface of the first substrate 10. This allows the plurality of non-conductive regions 20N to be arranged in a dispersed manner.

[0041] 2 shows an example of the arrangement of a plurality of openings 21M provided in the transparent conductive film 21. The openings 21M have, for example, a rectangular planar shape (XY plane) extending in the Y direction. The plurality of openings 21M are arranged side by side in the X direction. That is, the plurality of openings 21M are arranged in a stripe pattern. The openings 21M may have other planar shapes, such as an ellipse. The openings 21M may have a rectangular planar shape extending in the X direction, and the plurality of openings 21M may be arranged side by side in the Y direction.

[0042] 3 shows another example of the arrangement of the multiple openings 21M. The openings 21M may be arranged in a matrix, for example. The openings 21M have, for example, a rectangular planar shape (XY plane) and are arranged in a matrix in the X and Y directions. The openings 21M may have other planar shapes, such as a circle or a polygon.

[0043] The electrolyte layer 30 provided between the first electrode 20 and the second electrode 40 includes, for example, an electrolyte, an electrochromic material, a mediator, and a solvent. The electrolyte layer 30 may further include additives such as a thickener and a gelling polymer.

[0044] The electrolyte contained in the electrolyte layer 30 has a function of promoting the oxidation-reduction of the electrochromic material. The electrolyte is preferably a supporting electrolyte. For example, a lithium salt, a potassium salt, or a sodium salt can be used as the electrolyte. For example, the lithium salt can be lithium chloride (LiCl), lithium bromide (LiBr), lithium iodide (LiI), lithium tetrafluoroborate (LiBF 4 ) and lithium perchlorate (LiClO 4 ), etc. Potassium salts include potassium chloride (KCl), potassium bromide (KBr), and potassium iodide (KI). Sodium salts include sodium chloride (NaCl), sodium bromide (NaBr), and sodium iodide (NaI), etc. The electrolyte may include bromine, for example, tetrabutylammonium bromide (TBABr), etc.

[0045] An electrochromic material is a substance that causes an electrochemical oxidation-reduction reaction. In an electrochromic material, deposition on the electrode surface and dissolution into the electrolyte layer 30 occur due to electrochemical oxidation and reduction reactions. The electrochromic material contains, for example, a metal element. Specifically, the electrochromic material contains one or more metal elements selected from the group consisting of silver (Ag), bismuth (Bi), chromium (Cr), iron (Fe), cadmium (Cd), cobalt (Co), nickel (Ni), tin (Sn), lead (Pb), and copper (Cu). The electrochromic material contains, for example, silver, and is preferably silver nitrate (AgNO 3 ), silver perchlorate (AgClO 4 ) or silver bromide (AgBr), etc.

[0046] The mediator is a material that can perform oxidation and reduction with electrochemically lower energy than the electrochromic material. For example, the oxidized form of the mediator can provide and receive electrons from an electrochromic material such as silver as needed, thereby accelerating the dissolution of the electrochromic material into the electrolyte layer 30. For example, a salt of copper (II) ions can be used as the mediator, and specifically, copper chloride (CuCl 2 ), copper sulfate (CuSO 4 ) or copper bromide (CuBr 2 ) etc. can be used.

[0047] The solvent dissolves the electrolyte, the electrochromic material, and the mediator, and stably holds them. For example, a polar solvent, an organic solvent, an ionic liquid, an ion-conductive polymer, or a polymer electrolyte can be used as the solvent. For example, DMSO (Dimethyl Sulfoxide), propylene carbonate, N,N-dimethylformamide, tetrahydrofuran, acetonitrile, polyvinyl sulfuric acid, polystyrene sulfonic acid, or polyacrylic acid can be used as the solvent.

[0048] The second electrode 40 faces the first electrode 20 with the electrolyte layer 30 therebetween. The second electrode 40 is provided on the surface of the second substrate 50 that faces the first substrate 10. Hereinafter, the surface of the second substrate 50 that faces the first substrate 10 may also be referred to as the upper surface of the second substrate 50. The second electrode 40 is provided, for example, in contact with the upper surface of the second substrate 50.

[0049] The electrochromic element 1 has a single second electrode 40 connected to a second potential. The second electrode 40 has, for example, a transparent conductive film 41 (second transparent conductive film) having light transmitting properties. The transparent conductive film 41 is, for example, ITO, IZO, SnO 2 and ZnO. The transparent conductive film 41 may be made of the same material as the transparent conductive film 21, or may be made of a material different from that of the transparent conductive film 21. The second electrode 40 includes a single transparent conductive film 41 that is not electrically divided. The transparent conductive film 41 may have a laminated structure. The transparent conductive film 41 is provided, for example, over the entire surface of the second substrate 50. That is, the transparent conductive film 41 is formed of a so-called solid film. Here, the entire region of the second electrode 40 is made of a conductive region. In other words, the second electrode 40 has a conductive region at a rate higher than the rate of the conductive region 20C in the first electrode 20. The surface of the second electrode 40 (the surface facing the first electrode 20) is, for example, a flat surface.

[0050] The sealant 60 is provided between the first substrate 10 and the second substrate 50. The sealant 60 is arranged in a frame shape along the periphery of the first substrate 10 and the second substrate 50. The electrolyte layer 30 is filled in the space surrounded by the first substrate 10, the second substrate 50, and the sealant 60. The sealant 60 is made of, for example, an ultraviolet curing resin or a thermosetting resin.

[0051] The voltage application unit 70 applies a voltage between the first electrode 20 and the second electrode 40. The voltage application unit 70 includes, for example, a power source electrically connected to each of the transparent conductive film 21 and the transparent conductive film 41. When the voltage application unit 70 applies a voltage between the first electrode 20 and the second electrode 40, the electrochromic element 1 is switched between a light blocking state and a light transmitting state.

[0052] (Configuration of Transparent Display 2) FIG. 4 shows a planar (XY) configuration of a portion of the transparent display 2.

[0053] The transparent substrate 80 is a substrate having light transmitting properties. The transparent substrate 80 is made of, for example, glass, quartz, resin, etc. The transparent substrate 80 has, for example, a rectangular planar shape.

[0054] The driving substrate 91 is a substrate for driving the red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B. A plurality of driving substrates 91 are arranged in a matrix on the transparent substrate 80. The driving substrate 91 is arranged, for example, for each pixel. The driving substrate 91 includes, for example, a base material and a wiring layer provided on the base material. The base material is made of, for example, glass or resin. The wiring layer has, for example, a circuit pattern connected to the red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B, and a TFT (Thin Film Transistor) and wiring connected to the circuit pattern. The wiring layer may have other driving elements instead of the TFT. Alternatively, the transparent display 2 may be passive matrix driven.

[0055] The red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B provided on the driving substrate 91 are, for example, configured by micro LEDs (Micro Light Emitting Diodes), and have electrodes and semiconductor layers in this order from the driving substrate 91 side. The electrodes of the red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B are, for example, bonded to the circuit pattern of the driving substrate 91. The red light emitting element 92R emits light in the red wavelength region, the green light emitting element 92G emits light in the green wavelength region, and the blue light emitting element 92B emits light in the blue wavelength region. The semiconductor layers of the red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B may contain different semiconductor materials, or may contain the same semiconductor material in part or in whole.

[0056] The red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B have, for example, a quadrangular planar (XY plane) shape. The size of one side of the quadrangle is, for example, 1 μm or more and 100 μm or less. The red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B have, for example, a three-dimensional shape such as a substantially rectangular parallelepiped or a substantially cube. The red light emitting element 92R, the green light emitting element 92G, and the blue light emitting element 92B may have other planar shapes such as a circle. The transparent display 2 may further have a color filter, a sealing substrate, and the like.

[0057] The transparent display 2 is provided with a light-transmitting region 2a and a plurality of light-non-transmitting regions 2b. In the light-transmitting region 2a, light from the electrochromic element 1 side is transmitted through the transparent substrate 80 and is extracted to the display surface of the display device 100. In the light-non-transmitting region 2b, the transmission of light from the electrochromic element 1 side is blocked by the driving substrate 91 and the light-emitting element 92. In other words, the region in which the driving substrate 91 and the light-emitting element 92 are provided corresponds to the light-non-transmitting region 2b. The light-non-transmitting regions 2b are arranged, for example, in a matrix (FIG. 4).

[0058] The light-non-transmitting region 2b is preferably disposed at a position overlapping at least a part of the conductive region 20C of the first electrode 20 in a planar (XY) view. The light-transmitting region 2a is preferably disposed at a position overlapping at least a part of the non-conductive region 20N of the first electrode 20 in a planar view. Thereby, when the electrochromic element 1 is in a light-transmitting state, light from the electrochromic element 1 side is extracted to the display surface of the display device 100 through the non-conductive region 20N and the light-transmitting region 2a. Therefore, high light transmittance of the display device 100 is maintained.

[0059] (Method of Driving Electrochromic Element 1) Next, a method of driving the electrochromic element 1 will be described with reference to Figs. 5A to 5C, 6 and 7. Figs. 5A, 5B and 5C respectively show the no-voltage state S0, the light-shielding state S1 and the light-transmitting state S2 of the electrochromic element 1. Fig. 6 shows an example of the voltage applied between the first electrode 20 and the second electrode 40 by the voltage application unit 70. Fig. 7 shows the light transmittance of the electrochromic element 1 when the voltage shown in Fig. 6 is applied.

[0060] When no voltage is applied between the first electrode 20 and the second electrode 40, that is, when no voltage is applied, the electrochromic element 1 is in a no-voltage state S0 (FIG. 5A). At this time, for example, metal ions m such as silver ions + The electrochromic material, including is dissolved in the electrolyte layer 30.

[0061] Next, when a voltage V1 (FIG. 6) is applied between the first electrode 20 and the second electrode 40 so that the second electrode 40 serves as a cathode, the metal ions m + is reduced, and a metal m such as silver is deposited on the surface of the second electrode 40 (FIG. 5B). At this time, the light transmittance of the electrochromic element 1 decreases to about 1% (FIG. 7). That is, the electrochromic element 1 is in a light-shielding state S1. In this light-shielding state S1, for example, the deposited metal m reflects visible light, forming a mirror surface on the surface of the second electrode 40.

[0062] Next, when a voltage V1 and a reverse bias voltage V2 (FIG. 6) are applied between the first electrode 20 and the second electrode 40, the metal m deposited on the surface of the second electrode 40 is oxidized, and metal ions m + (FIG. 5C). At this time, the light transmittance of the electrochromic element 1 increases to about 75% (FIG. 7). That is, the electrochromic element 1 enters the light transmitting state S2. For example, the absolute value of the voltage V2 is substantially the same as the absolute value of the voltage V1 (|V1|=|V2| or |V1|≒|V2|). The time from when the voltage V2 is applied between the first electrode 20 and the second electrode 40 until the light transmittance of the electrochromic element 1 reaches about 75% is, for example, time t1.

[0063] When a voltage V2 is applied between the first electrode 20 and the second electrode 40, metal ions m + A part of the metal ions m+ is reduced on the surface of the first electrode 20, and the metal m is precipitated in the conductive region 20C of the first electrode 20. In this embodiment, the first electrode 20 has a non-conductive region 20N. In this non-conductive region 20N, the reduction reaction of the metal ions m+ does not proceed, and the metal m is not precipitated. Therefore, the light transmittance is maintained in the non-conductive region 20N.

[0064] When a voltage V1 (FIG. 6) is applied again to the electrochromic element 1 in the light transmitting state S2, the metal ions m + is reduced, and metal m is deposited on the surface of the second electrode 40 (FIG. 5B). That is, the electrochromic element 1 is again in the light-blocking state S1. The time from when the voltage V1 is applied between the first electrode 20 and the second electrode 40 until the light transmittance of the electrochromic element 1 becomes about 1% is, for example, time t2. For example, time t1 and time t2 are substantially the same length (t1=t2 or t1≈t2).

[0065] (Functions and Effects of the Electrochromic Element 1 and the Display Device 100) In the electrochromic element 1 and the display device 100 of this embodiment, the first electrode 20 has a non-conductive region 20N. As a result, even if a relatively large voltage V2 is applied between the first electrode 20 and the second electrode 40 when switching from the light-shielding state S1 to the light-transmitting state S2, the non-conductive region 20N maintains light transmittance. This makes it possible to shorten the time t1 required to switch from the light-shielding state S1 to the light-transmitting state S2. Hereinafter, this effect will be described using a comparative example.

[0066] FIG. 8 shows an example of a cross-sectional configuration of an electrochromic element 1000 according to a comparative example. The first electrode 20 of this electrochromic element 1000 does not have a non-conductive region (for example, the non-conductive region 20N in FIG. 1). In other words, the entire region of the first electrode 20 is composed of a conductive region. When a voltage V2 is applied between the first electrode 20 and the second electrode 40 of this electrochromic element 1000, the electrochromic element 1000 enters a light-transmitting state S2. However, when a relatively large voltage V2 is applied, metal m is likely to precipitate on the surface of the first electrode 20. Therefore, the metal m precipitated over the entire surface of the first electrode 20 may impair the light transmittance of the light-transmitting state S2.

[0067] 9 shows an example of a voltage applied between the first electrode 20 and the second electrode 40 of the electrochromic element 1000. In the electrochromic element 1000, by applying a voltage V3 smaller than the voltage V2, deposition of the metal m on the surface of the first electrode 20 in the light-transmitting state S2 is suppressed. That is, light transparency in the light-transmitting state S2 can be maintained. However, the smaller voltage V3 slows down the progress of the oxidation-reduction reaction compared to the larger voltage V2. Therefore, the time t1000 required to switch from the light-shielding state S1 to the light-transmitting state S2 is longer than the time t2 required to switch from the light-transmitting state S2 to the light-shielding state S1.

[0068] In contrast, in the electrochromic element 1 and the display device 100, the first electrode 20 has a non-conductive region 20N. As a result, even if a voltage V2 larger than the voltage V3 is applied when switching from the light-shielding state S1 to the light-transmitting state S2, the non-conductive region 20N maintains light transparency. For example, the magnitude of the voltage V2 is substantially the same as the magnitude of the voltage V1 applied when switching from the light-transmitting state S2 to the light-shielding state S1. Therefore, it is possible to shorten the time t1 required to switch from the light-shielding state S1 to the light-transmitting state S2 compared to the time t1000. For example, the time t1 is substantially the same length as the time t2 required to switch from the light-transmitting state S2 to the light-shielding state S1.

[0069] Furthermore, in the first electrode 20, a plurality of non-conductive regions 20N are arranged in a predetermined pattern. This relaxes the film stress of the metal m deposited in the conductive region 20C when the electrochromic element 1 is in the light-transmitting state S2. This makes it difficult for the film of the metal m to peel off from the surface of the first electrode 20, and allows the light transmittance to be maintained more stably.

[0070] When the electrochromic element 1 is set in the light-transmitting state S2 and an image is displayed on the transparent display 2, it is possible to display an image using high light transmittance. On the other hand, when the electrochromic element 1 is set in the light-shielding state S1 and an image is displayed on the transparent display 2, it is possible to display an image with high contrast. In the display device 100 having the electrochromic element 1 and the transparent display 2, it is possible to display images with a high degree of freedom by controlling the light transmittance of the electrochromic element 1.

[0071] In the following, a modified example of the electrochromic element 1 according to the above embodiment will be described. In order to avoid duplication of explanation, detailed explanation of the same configuration as that of the electrochromic element 1 according to the above embodiment will be omitted.

[0072] <Variation 1> Fig. 10 shows an example of a cross-sectional (XZ cross-sectional) configuration of an electrochromic element (electrochromic element 1A) according to Modification 1. Fig. 10 corresponds to Fig. 1 showing the electrochromic element 1 of the above embodiment. In this electrochromic element 1A, the first electrode 20 has a non-conductive region 20N, and the second electrode 40 also has a non-conductive region 40N (second non-conductive region). Except for this point, the electrochromic element 1A according to Modification 1 has the same configuration as the electrochromic element 1 described in the above embodiment.

[0073] The non-conductive region 40N is, for example, an opening 41M provided in the transparent conductive film 41. In other words, the opening 41M is selectively provided in the non-conductive region 40N. The second electrode 40 has, for example, a plurality of non-conductive regions 40N, which are arranged in a dispersed manner. For example, in the electrochromic element 1, a plurality of openings 41M are formed in a predetermined pattern in a single transparent conductive film 41 provided on the upper surface of the second substrate 50. This allows the plurality of non-conductive regions 40N to be arranged in a dispersed manner. The region of the second electrode 40 other than the non-conductive region 40N is a conductive region 40C (second conductive region). The proportion of the conductive region 40C in the second electrode 40 is higher than the proportion of the conductive region 20C in the first electrode 20. This maintains the light-shielding property of the electrochromic element 1A in the light-shielding state S1.

[0074] 11 shows an example of the arrangement of a plurality of openings 41M provided in the transparent conductive film 41. The openings 41M have, for example, a rectangular planar shape (XY plane) extending in the Y direction. The plurality of openings 41M are arranged side by side in the X direction. That is, the plurality of openings 41M are arranged in a stripe pattern. The openings 41M may have another planar shape, such as an ellipse.

[0075] 12 shows another example of the arrangement of the multiple openings 41M. The openings 41M may be arranged in a matrix, for example. The openings 41M have, for example, a rectangular planar shape (XY plane) and are arranged in a matrix in the X and Y directions. The openings 41M may have other planar shapes, such as a circle or a polygon.

[0076] In the electrochromic element 1A according to the first modification, the first electrode 20 also has a non-conductive region 20N. This makes it possible to apply a larger voltage V2 when switching from the light-shielding state S1 to the light-transmitting state S2, thereby shortening the time t1 required for switching from the light-shielding state S1 to the light-transmitting state S2. The second electrode 40 also has a non-conductive region 40N. This alleviates the film stress of the metal m deposited on the surface of the second electrode 40. This makes it difficult for the metal m to peel off from the surface of the second electrode 40, and the light-shielding properties can be maintained more stably. In particular, since the metal m is less likely to peel off from the surface of the second electrode 40, which has a larger area than the first electrode 20, peeling of the metal m can be more effectively suppressed.

[0077] <Variation 2> Fig. 13 shows an example of a cross-sectional (XZ cross-sectional) configuration of an electrochromic element (electrochromic element 1B) according to Modification 2. Fig. 13 corresponds to Fig. 1 showing the electrochromic element 1 of the above embodiment. The first electrode 20 of this electrochromic element 1B has an insulating film 22 provided between the transparent conductive film 21 and the electrolyte layer 30. The second electrode 40 has an insulating film 42 provided between the transparent conductive film 41 and the electrolyte layer 30. Except for this point, the electrochromic element 1B according to Modification 2 has the same configuration as the electrochromic element 1 described in the above embodiment.

[0078] The insulating film 22 is selectively disposed in the non-conductive region 20N of the first electrode 20. In other words, the non-conductive region 20N is constituted by the insulating film 22. The first electrode 20 has, for example, a plurality of insulating films 22 disposed separately from each other. The insulating film 22 is, for example, made of silicon nitride (SiN), silicon oxide (SiO 2 ), an oxynitride film (SiON), an acrylic resin, an epoxy resin, a polyimide resin, etc. The transparent conductive film 21 is provided, for example, over the entire lower surface of the first substrate 10. That is, the transparent conductive film 21 is formed of a so-called solid film.

[0079] The insulating film 42 is selectively disposed in the non-conductive region 40N of the second electrode 40. In other words, the non-conductive region 40N is constituted by the insulating film 42. The second electrode 40 has, for example, a plurality of insulating films 42 arranged in an island shape. The insulating film 42 is made of, for example, silicon nitride, silicon oxide (SiO 2 ), an oxynitride film (SiON), an acrylic resin, an epoxy resin, a polyimide resin, etc. The transparent conductive film 41 is provided, for example, over the entire upper surface of the second substrate 50. That is, the transparent conductive film 41 is formed of a so-called solid film.

[0080] In the electrochromic element 1B according to the second modification, the first electrode 20 also has a non-conductive region 20N. This makes it possible to apply a larger voltage V2 when switching from the light-shielding state S1 to the light-transmitting state S2, thereby shortening the time t1 required for switching from the light-shielding state S1 to the light-transmitting state S2. In addition, the non-conductive region 20N of the first electrode 20 is made of an insulating film 22, and the non-conductive region 40N of the second electrode 40 is made of an insulating film 42. This makes it possible to form the transparent conductive film 21 and the transparent conductive film 41 with a solid film. Therefore, the resistance of the first electrode 20 and the second electrode 40 is prevented from increasing, and the IR drop is reduced. This makes it possible to further shorten the time required for switching between the light-shielding state S1 and the light-transmitting state S2.

[0081] 14 and 15 show another example of the electrochromic element 1B. In the electrochromic element 1B, the first electrode 20 may not have an insulating film 22. In this case, the non-conductive region 20N of the first electrode 20 is formed, for example, by an opening 21M of the transparent conductive film 21 (FIG. 14). Alternatively, in the electrochromic element 1B, the second electrode 40 may not have an insulating film 42. In this case, the non-conductive region 40N of the second electrode 40 is formed, for example, by an opening 41M of the transparent conductive film 41 (not shown). The second electrode 40 may not have a non-conductive region 40N (FIG. 15).

[0082] <Variation 3> FIG. 16 shows an example of a cross-sectional (XZ cross-sectional) configuration of an electrochromic element (electrochromic element 1C) according to Modification 3. FIG. 16 corresponds to FIG. 1 showing the electrochromic element 1 of the above embodiment. The first electrode 20 of this electrochromic element 1C has a low-resistance conductive film 23 (first low-resistance conductive film) laminated on a transparent conductive film 21. The second electrode 40 has a low-resistance conductive film 43 (second low-resistance conductive film) laminated on a transparent conductive film 41. Except for this point, the electrochromic element 1C according to Modification 3 has the same configuration as the electrochromic element 1A described in Modification 1 above.

[0083] The low-resistance conductive film 23 has a resistivity lower than that of the transparent conductive film 21. The low-resistance conductive film 23 is, for example, a conductive film having a light transmittance lower than that of the transparent conductive film 21. The low-resistance conductive film 23 contains, for example, at least one of aluminum (Al), aluminum alloy, silver (Ag), silver alloy, molybdenum (Mo), molybdenum alloy, copper (Cu), copper oxide (CuO), copper alloy, chromium (Cr), and nickel (Ni). The first electrode 20 may have a low-resistance conductive film 23 having a laminated structure. For example, the low-resistance conductive film 23 having a laminated structure has two blackened layers and a wiring layer provided between the blackened layers. The blackened layer contains, for example, chromium, nickel plating, or copper oxide. The wiring layer contains copper or a copper alloy. By having the first electrode 20 have the low-resistance conductive film 23 including a blackening layer, external light reflection caused by the low-resistance conductive film 23 is suppressed, and the visibility of the display device 100 can be improved.

[0084] The low-resistance conductive film 23 is disposed, for example, in at least a part of the conductive region 20C. In other words, it is preferable that the low-resistance conductive film 23 is disposed excluding the non-conductive region 20N. This makes it possible to suppress a decrease in light transmittance caused by the low-resistance conductive film 23.

[0085] The first electrode 20 has, for example, a low-resistance conductive film 23 and a transparent conductive film 21 in this order from the first substrate 10 side. The first electrode 20 may have, for example, a transparent conductive film 21 and a low-resistance conductive film 23 in this order from the first substrate 10 side. However, in this structure, the low-resistance conductive film 23 is in direct contact with the electrolyte layer, so that the low-resistance conductive film 23 does not dissolve in the electrolyte layer, a material having a smaller ionization tendency than the metal m or the mediator, such as Au or Pt, is used. Alternatively, even if the low-resistance conductive film 23 has a larger ionization tendency than the metal m or the mediator, a material such as silicon nitride or silicon oxide (SiO 2 ), an oxynitride film (SiON), an acrylic resin, an epoxy resin, a polyimide resin, or the like may be formed.

[0086] The low-resistance conductive film 43 has a resistivity lower than that of the transparent conductive film 41. The low-resistance conductive film 43 is, for example, a conductive film having a light transmittance lower than that of the transparent conductive film 41. The low-resistance conductive film 43 contains, for example, at least one of aluminum (Al), aluminum alloy, silver (Ag), silver alloy, molybdenum (Mo), molybdenum alloy, copper (Cu), copper oxide (CuO), copper alloy, chromium (Cr), and nickel (Ni). The second electrode 40 may have a low-resistance conductive film 43 having a laminated structure. For example, the low-resistance conductive film 43 having a laminated structure has two blackening layers and a wiring layer provided between the blackening layers. The blackening layer contains, for example, chromium, nickel plating, or copper oxide. The wiring layer contains copper or a copper alloy. By having the second electrode 40 have the low-resistance conductive film 43 including a blackening layer, external light reflection caused by the low-resistance conductive film 43 is suppressed, and the visibility of the display device 100 can be improved.

[0087] At least a part of the low-resistance conductive film 43 is preferably disposed in a position facing the low-resistance conductive film 23, and more preferably disposed in a position overlapping the conductive region 20C in a planar (XY) view. The low-resistance conductive film 43 is further preferably disposed in a position not overlapping the non-conductive region 20N in a planar view. This suppresses a decrease in light transmittance caused by the low-resistance conductive film 43.

[0088] The second electrode 40 has, for example, a low-resistance conductive film 43 and a transparent conductive film 41 in this order from the second substrate 50 side. The second electrode 40 may have, for example, a transparent conductive film 41 and a low-resistance conductive film 43 in this order from the second substrate 50 side. However, in this structure, the low-resistance conductive film 23 is in direct contact with the electrolyte layer, so that the low-resistance conductive film 23 does not dissolve in the electrolyte layer, a material having a smaller ionization tendency than the metal m or the mediator, such as Au or Pt, is used. Alternatively, even if the low-resistance conductive film 23 has a larger ionization tendency than the metal m or the mediator, a material such as silicon nitride or silicon oxide (SiO 2), an oxynitride film (SiON), an acrylic resin, an epoxy resin, a polyimide resin, or the like may be formed.

[0089] In the electrochromic element 1C according to the third modification, the first electrode 20 also has a non-conductive region 20N. This makes it possible to apply a larger voltage V2 when switching from the light-shielding state S1 to the light-transmitting state S2, thereby shortening the time t1 required for switching from the light-shielding state S1 to the light-transmitting state S2. In addition, the first electrode 20 has a low-resistance conductive film 23 having a lower resistivity than the transparent conductive film 21, and the second electrode 40 has a low-resistance conductive film 43 having a lower resistivity than the transparent conductive film 41. This prevents the first electrode 20 and the second electrode 40 from becoming high-resistance, thereby reducing the IR drop. This makes it possible to further shorten the time required for switching between the light-shielding state S1 and the light-transmitting state S2.

[0090] 17 to 21 show another example of the electrochromic element 1C. In the electrochromic element 1C, the non-conductive region 20N of the first electrode 20 may be formed by the insulating film 22, and the non-conductive region 40N of the second electrode 40 may be formed by the insulating film 42 (FIG. 17). The second electrode 40 may not have the non-conductive region 40N (FIGS. 18 and 19). The non-conductive region 20N of the first electrode 20 may be formed by the opening 21M of the transparent conductive film 21, and the non-conductive region 40N of the second electrode 40 may be formed by the insulating film 42 (FIG. 20). The non-conductive region 20N of the first electrode 20 may be formed by the insulating film 22, and the non-conductive region 40N of the second electrode 40 may be formed by the opening 41M of the transparent conductive film 41 (not shown). The low-resistance conductive film 43 may be disposed at a position shifted from the insulating film 42 (FIG. 17), or may be disposed at a position overlapping the insulating film 42 (FIG. 21).

[0091] The configuration of the display device 100 having the electrochromic elements 1, 1A, 1B, and 1C described above is a main configuration for explaining the features of the above embodiment, but is not limited to the above configuration and can be modified in various ways within the scope of the claims. Furthermore, the configuration of a general display device is not excluded.

[0092] For example, in the above embodiment, an example has been described in which the surface of the second electrode 40 is flat, but the surface of the second electrode 40 may be uneven. This uneven surface can be formed, for example, by fine particles of ITO or ATO (antimony-doped tin oxide). When the surface of the second electrode 40 is uneven, in the light-shielding state S1 of the electrochromic element 1, plasmon absorption and scattering of visible light occurs due to the deposited metal m, and a black surface is formed on the surface of the second electrode 40.

[0093] In the above embodiment, an example has been described in which the voltage V2 is applied between the first electrode 20 and the second electrode 40 when switching from the light-blocking state S1 to the light-transmitting state S2. However, the voltage application unit 70 may apply a voltage smaller than the voltage V2 between the first electrode 20 and the second electrode 40 when switching from the light-blocking state S1 to the light-transmitting state S2.

[0094] In the above-described embodiment, the electrochromic elements 1, 1A, 1B, and 1C have a single first electrode 20 connected to a first potential and a single second electrode 40 connected to a second potential. However, the electrochromic elements 1, 1A, 1B, and 1C may have a plurality of first electrodes 20 and a plurality of second electrodes 40, each having a non-conductive region. In other words, the first electrode 20 may be electrically divided, and the second electrode 40 may be electrically divided. This allows the electrochromic elements 1, 1A, 1B, and 1C to be partially switched between a light-shielding state S1 and a light-transmitting state S2.

[0095] In the above embodiment, the light-emitting element 92 is configured by a micro LED, but the light-emitting element 92 may be configured by an LED larger than a micro LED, for example, a mini LED or a general LED having a diameter of 100 μm or more. Furthermore, the light-emitting element 92 may be configured by other light-emitting elements such as an OLED (Organic Light Emitting Diode) and an inorganic EL element. The transparent display 2 may have a display element other than the light-emitting element, and the transparent display 2 may be a liquid crystal display using a liquid crystal layer or the like.

[0096] In addition, in the above-described embodiment, a case has been described in which light in the red wavelength range, light in the green wavelength range, and light in the blue wavelength range are extracted from the transparent display 2, but the wavelength range of the light extracted from the transparent display 2 is not limited to this. [Explanation of symbols]

[0097] 100 display devices, 1, 1A, 1B, 1C Electrochromic element, 10 first substrate, 20 first electrode, 21,41 Transparent conductive film, 21M, 41M opening, 22,42 Insulating film, 23,43 Conductive film, 30 electrolyte layer, 40 second electrode, 50 second substrate, 60 Sealing materials, 70 Voltage application unit, 80 transparent substrate, 91 Drive board, 92 Light emitting element, m metal.

Claims

1. a first electrode having a first conductive region and a first non-conductive region and connected to a first potential; a second electrode provided opposite the first electrode and having a second conductive region at a ratio higher than a ratio of the first conductive region to the first electrode; an electrolyte layer including an electrochromic material and disposed between the first electrode and the second electrode; An electrochromic element comprising:

2. 10. The electrochromic device of claim 1, wherein the second electrode further comprises a second non-conductive region and is connected to a second potential.

3. The electrochromic device of claim 1 , wherein the first electrode comprises a plurality of the first non-conductive regions.

4. 4. The electrochromic device of claim 3, wherein the first non-conductive regions are arranged in a predetermined pattern.

5. The electrochromic device according to claim 4 , wherein each of the plurality of first non-conductive regions has a rectangular planar shape.

6. the first electrode includes a first transparent conductive film; The electrochromic device of claim 1 , wherein the second electrode comprises a second transparent conductive film.

7. The electrochromic device according to claim 6 , wherein the first electrode further includes an insulating film provided between the first transparent conductive film and the electrolyte layer and selectively disposed in the first non-conductive region.

8. The electrochromic device according to claim 6 , wherein the first transparent conductive film has an opening selectively provided in the first non-conductive region.

9. The electrochromic element according to claim 6 , wherein the first electrode is provided by being laminated on the first transparent conductive film, and further includes a first low-resistance conductive film having a specific resistance lower than that of the first transparent conductive film.

10. The electrochromic element according to claim 9 , wherein the first low-resistance conductive film is provided on at least a portion of the first conductive region.

11. the second electrode is provided by being laminated on the second transparent conductive film, and further includes a second low-resistance conductive film having a specific resistance lower than that of the second transparent conductive film; 10. The electrochromic element according to claim 9, wherein at least a portion of the second low-resistance conductive film is disposed in a position facing the first low-resistance conductive film.

12. The electrochromic device according to claim 6 , wherein at least one of the first transparent conductive film and the second transparent conductive film is a solid film.

13. 2. The electrochromic element according to claim 1, which can take a light-shielding state in which the electrochromic material is precipitated on the surface of the second electrode, and a light-transmitting state in which the electrochromic material is dissolved in the electrolyte layer.

14. The electrochromic element according to claim 13 , further comprising a voltage application section that applies a voltage between the first electrode and the second electrode to switch between the light blocking state and the light transmitting state.

15. The electrochromic element according to claim 14 , wherein the voltage application unit applies, when switching from the light-shielding state to the transmitting state, a voltage having substantially the same magnitude as a voltage applied when switching from the light-transmitting state to the light-shielding state.

16. The electrochromic device according to claim 1 ; a transparent display laminated to the electrochromic element and having a light-transmitting region and a light-opaque region; A display device comprising:

17. The display device according to claim 16 , wherein at least a portion of the first conductive region is disposed in a position overlapping the light-opaque region.

Images