Flexible wiring substrate, light control device, and light control system

Abstract

This light control device comprises: a pair of transparent electrode layers configured from a first transparent electrode layer and a second transparent electrode layer; a light control layer disposed between the first transparent electrode layer and the second transparent electrode layer; and a first flexible wiring substrate connected to the first transparent electrode layer. The first transparent electrode layer comprises a plurality of first divided electrodes electrically separated by a first insulation part. The first flexible wiring substrate comprises a first electrode connection part that is connected to the first divided electrode; and a plurality of first terminals that are each connected in parallel to the first electrode connection part and are for connecting the first electrode connection part to a drive part.

Description

Flexible Wiring Substrate, Dimming Device, and Dimming System

[0001] The present disclosure relates to a flexible wiring substrate joined to a transparent electrode layer of a dimming device, a dimming device including the flexible wiring substrate, and a dimming system.

[0002] A dimming device applied to windows of buildings or vehicles includes a liquid crystal composition between a first transparent electrode layer and a second transparent electrode layer. The orientation of the liquid crystal composition changes according to a driving voltage applied to the transparent electrode layer. In a dimming device enabling divided driving, the first transparent electrode layer is divided into a plurality of transparent electrode portions. Divided driving for driving the liquid crystal composition for each transparent electrode portion gives high design quality to the dimming range (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2020-126153

[0004] The improvement in design quality by divided driving has expanded the application targets of dimming devices. On the other hand, the arrangement of wiring connecting the driving unit to the dimming device varies depending on the application target on which each dimming device is mounted. Therefore, it is desired to reduce the mounting load of the wiring so that the arrangement of the wiring conforms to the specifications of the dimming device.

[0005] One aspect of the dimming device includes a pair of transparent electrode layers composed of a first transparent electrode layer and a second transparent electrode layer, a dimming layer disposed between the first transparent electrode layer and the second transparent electrode layer, and a flexible wiring substrate connected to the first transparent electrode layer. Each of the transparent electrode layers includes a plurality of divided electrodes electrically divided by insulating portions, and the flexible wiring substrate includes an electrode connection portion connected to the divided electrodes of the first transparent electrode layer, and a plurality of terminals connected in parallel to the electrode connection portion and for connecting the electrode connection portion to a driving unit that drives the dimming layer.

[0006] One embodiment of a dimming system comprises a pair of transparent electrode layers consisting of a first transparent electrode layer and a second transparent electrode layer; a dimming layer disposed between the first transparent electrode layer and the second transparent electrode layer; a flexible wiring board electrically connected to the first transparent electrode layer; a drive unit for driving the dimming layer; and wiring electrically connecting the flexible wiring board to the drive unit. Each transparent electrode layer comprises a plurality of divided electrodes electrically separated by an insulating portion; the flexible wiring board comprises an electrode connection portion electrically connected to the first transparent electrode layer; a plurality of parallel wirings connected in parallel to the electrode connection portion and extending from the electrode connection portion; and an insulating film supporting the electrode connection portion and the parallel wirings, wherein a portion of the plurality of parallel wirings is connected to a terminal for connecting the electrode connection portion to the drive unit; and the other portion of the plurality of parallel wirings forms a cut mark, which is cut together with the insulating film to be shorter than the portion of the plurality of parallel wirings.

[0007] One embodiment of a flexible wiring board is a flexible wiring board connected to a dimming sheet, wherein the dimming sheet comprises a pair of transparent electrode layers composed of a first transparent electrode layer and a second transparent electrode layer, and a dimming layer disposed between the first transparent electrode layer and the second transparent electrode layer, each of the transparent electrode layers comprises a plurality of divided electrodes electrically separated by an insulating portion, the flexible wiring board comprises a single electrode connection portion extending in the direction in which the divided electrodes of the first transparent electrode layer are aligned and having comb teeth aligned in that direction, with the plurality of divided electrodes connected in parallel, and a plurality of terminals connected in parallel to the electrode connection portion and arranged at a constant interval along that direction.

[0008] Figure 1 is a configuration diagram showing the dimming system. Figure 2 is a cross-sectional view showing a part of the dimming sheet. Figure 3 is a plan view showing the surface structure of the flexible wiring board. Figure 4 is a plan view showing the back structure of the flexible wiring board. Figure 5 is a cross-sectional view showing the connection structure of the flexible wiring board. Figure 6 is a cross-sectional view showing the connection structure of the flexible wiring board. Figure 7 is a configuration diagram showing the dimming system.

[0009] [Dimming System 10] As shown in Figure 1, the dimming system 10 comprises a dimming device 20, a drive unit 60, a first wiring 61, and a second wiring 62. The dimming device 20 is connected to the drive unit 60 via the first wiring 61. The dimming device 20 is connected to the drive unit 60 via the second wiring 62. The drive unit 60 applies a common voltage to the dimming device 20 through the first wiring 61. The drive unit 60 applies a control voltage to the dimming device 20 through the second wiring 62.

[0010] There may be two or more first wires 61 connecting the drive unit 60 to the dimming device 20. If there are two or more first wires 61, the drive unit 60 applies a common voltage to all of the first wires 61. There are two or more second wires 62 connecting the drive unit 60 to the dimming device 20. The drive unit 60 has a mode in which it applies a different control voltage to each of the second wires 62, and a mode in which it applies the same control voltage to all of the second wires 62.

[0011] [Dimming device 20] The dimming device 20 comprises a dimming sheet 30, a first flexible wiring board 40, and a second flexible wiring board 50. The first wiring 61 electrically connects the first flexible wiring board 40 to the drive unit 60. The second wiring 62 electrically connects the second flexible wiring board 50 to the drive unit 60. The dimming sheet 30 may be attached to a transparent substrate such as a transparent glass substrate or a transparent resin substrate, or it may be sandwiched between transparent substrates.

[0012] As shown in Figure 2, the dimming sheet 30 comprises a second transparent support layer 31, a second transparent electrode layer 32, a first transparent support layer 35, a first transparent electrode layer 34, and a dimming layer 33. The first transparent support layer 35 and the second transparent support layer 31 are transparent substrates that transmit light in the visible region. The first transparent support layer 35 supports the first transparent electrode layer 34 on its upper surface as shown in Figure 2. The second transparent support layer 31 supports the second transparent electrode layer 32 on its lower surface as shown in Figure 2. The side of the first transparent support layer 35 opposite to the first transparent electrode layer 34 is the back surface of the dimming sheet 30. The side of the second transparent support layer 31 opposite to the second transparent electrode layer 32 is the front surface of the dimming sheet 30.

[0013] The constituent materials of the first transparent support layer 35 and the second transparent support layer 31 may be synthetic resins or inorganic compounds, respectively. The constituent materials of the first transparent support layer 35 and the second transparent support layer 31 may be the same as or different from each other. The synthetic resin may be at least one selected from the group consisting of polyester, polycarbonate, polypropylene, polystyrene, acrylic resin, nylon resin, polyurethane, polyethylene, polyvinyl alcohol, polyvinyl chloride, polyimide, polysulfone, cycloolefin polymer, and triacetylcellulose. The inorganic compound may be at least one selected from the group consisting of silicon dioxide, silicon oxynitride, and silicon nitride.

[0014] The first transparent electrode layer 34 and the second transparent electrode layer 32 each have transparent conductivity that transmits light in the visible region. The first transparent electrode layer 34 may be laminated on the upper surface of the first transparent support layer 35. The second transparent electrode layer 32 may be laminated on the lower surface of the second transparent support layer 31. The first transparent electrode layer 34 comprises one or more first insulating portions 34A and a plurality of first divided electrodes 34B. The second transparent electrode layer 32 comprises one or more second insulating portions 32A and a plurality of second divided electrodes 32B.

[0015] Returning to Figure 1, the first insulating portion 34A has a linear shape extending in the second direction D2. The first insulating portion 34A may have a straight line extending in the second direction D2, or it may have a curved shape such as a bent line or an arc. When the first transparent electrode layer 34 comprises a plurality of first insulating portions 34A, the plurality of first insulating portions 34A are arranged at intervals in the first direction D1 which is perpendicular to the second direction D2. The first transparent electrode layer 34 shown in Figure 1 comprises four first insulating portions 34A, each having a straight line extending in the second direction D2 and at a certain interval in the first direction D1.

[0016] The first insulating portion 34A insulates adjacent first divided electrodes 34B in the first direction D1 from each other. The first insulating portion 34A is integral with the first divided electrodes 34B that are insulated by the first insulating portion 34A. The first transparent support layer 35 is continuous between adjacent first divided electrodes 34B.

[0017] The second insulating portion 32A has a linear shape extending in the second direction D2. The second insulating portion 32A has the same shape as the first insulating portion 34A. When the second transparent electrode layer 32 comprises a plurality of second insulating portions 32A, the plurality of second insulating portions 32A are arranged in the first direction D1 at intervals equal to the intervals of the first insulating portions 34A. The second transparent electrode layer 32 shown in Figure 1 comprises four second insulating portions 32A, each having a linear shape extending in the second direction D2 and spaced at a constant interval in the first direction D1.

[0018] The second insulating portion 32A insulates adjacent second divided electrodes 32B in the first direction D1. The second insulating portion 32A is integral with the second divided electrodes 32B insulated by the second insulating portion 32A. The second transparent support layer 31 is continuous between adjacent second divided electrodes 32B. The second insulating portion 32A overlaps with the first insulating portion 34A in the thickness direction of the dimming layer 33 (see Figure 2). The first insulating portion 34A and the second insulating portion 32A may be formed by the same laser irradiation of the first transparent electrode layer 34 and the second transparent electrode layer 32. The same laser irradiation means a single laser irradiation in which the first insulating portion 34A is formed on the first transparent electrode layer 34 and the second insulating portion 32A is formed on the second transparent electrode layer 32.

[0019] Multiple first divided electrodes 34B are arranged along a first direction D1. Two first divided electrodes 34B adjacent to each other in the first direction D1 are insulated by a first insulating portion 34A. Multiple second divided electrodes 32B are arranged along the first direction D1. Two second divided electrodes 32B adjacent to each other in the first direction D1 are insulated by a second insulating portion 32A. The first divided electrodes 34B and the second divided electrodes 32B each extend along a second direction D2 from a second end to a first end. One first flexible wiring board 40 is connected to the first end 34BE of the multiple first divided electrodes 34B. One second flexible wiring board 50 is connected to each second end 32BE of the multiple second divided electrodes 32B.

[0020] The constituent materials of the first transparent electrode layer 34 and the second transparent electrode layer 32 may each be at least one selected from the group consisting of polymers containing indium tin oxide (ITO), fluorine-doped tin oxide (FTO), tin oxide, zinc oxide, carbon nanotubes (CNTs), poly(3,4-ethylenedioxythiophene) (PEDOT), and multilayer films containing Ag alloy thin films.

[0021] [Dimming layer 33] The dimming layer 33 changes its optical state from transparent to opaque, or from opaque to transparent, by the power supplied between the first divided electrode 34B and the second divided electrode 32B. The dimming layer 33 may be a polymer dispersed liquid crystal element, a polymer network liquid crystal element, or a guest-host liquid crystal element. The dimming layer 33 may be a suspended particle device, a photochromic element, an electrochromic element, or an electrokinetic element.

[0022] An example of a light-adjusting layer 33 comprises a transparent polymer layer and a liquid crystal composition. The transparent polymer layer partitions the voids into which the liquid crystal composition is filled. The shape of the voids may be spherical, ellipsoidal, or irregular. The structure of the light-adjusting layer 33 may be a polymer network type, a polymer dispersion type, or a capsule type. A polymer network type light-adjusting layer 33 comprises a polymer network having a three-dimensional mesh structure. The polymer network is an example of a transparent polymer layer, and the liquid crystal composition is held in the interconnected mesh voids of the polymer network. A polymer dispersion type light-adjusting layer 33 comprises a transparent polymer layer partitioning a number of isolated voids, and the liquid crystal composition is held in the voids dispersed in the transparent polymer layer. A capsule type light-adjusting layer 33 holds the liquid crystal composition in the voids within capsules dispersed in the transparent polymer layer.

[0023] The transparent polymer layer is a polymer of a photopolymerizable compound. Photopolymerizable compounds are, for example, UV polymerizable compounds. UV polymerizable compounds include, for example, acrylate compounds, methacrylate compounds, stilbene compounds, diacrylate compounds, dimethacrylate compounds, triacrylate compounds, trimethacrylate compounds, tetraacrylate compounds, tetramethacrylate compounds, and oligomers of these compounds. Examples of acrylate compounds include butyl ethyl acrylate and cyclohexyl acrylate. Examples of methacrylate compounds include N,N-dimethylaminoethyl methacrylate and phenoxyethyl methacrylate.

[0024] The liquid crystal composition comprises a liquid crystal compound and a dichroic dye. The liquid crystal composition may also contain viscosity reducers, defoamers, antioxidants, weather-resistant agents, etc. Examples of liquid crystal compounds include Schiff base compounds, azo compounds, azoxy compounds, biphenyl compounds, terphenyl compounds, benzoic acid ester compounds, tran compounds, pyrimidine compounds, pyridazine compounds, cyclohexanecarboxylic acid ester compounds, phenylcyclohexane compounds, biphenylcyclohexane compounds, dicyanobenzene compounds, naphthalene compounds, and dioxane compounds.

[0025] Dichroic dyes are driven by a guest-host mechanism using liquid crystal compounds as the host, thereby exhibiting color. Dichroic dyes include polyiodine, azo compounds, anthraquinone compounds, naphthoquinone compounds, azomethine compounds, tetrazine compounds, quinophthalone compounds, merocyanine compounds, perylene compounds, and dioxazine compounds.

[0026] In addition to the first transparent support layer 35, the first transparent electrode layer 34, the second transparent support layer 31, the second transparent electrode layer 32, and the photochromic layer 33, the photochromic sheet 30 may also have a functional layer. An example of a functional layer is one that protects the photochromic layer 33, the first transparent electrode layer 34, and the second transparent electrode layer 32. The functional layer with protective function may be a gas barrier layer or an ultraviolet barrier layer. The gas barrier layer may be placed between the first transparent support layer 35 and the first transparent electrode layer 34, or between the second transparent support layer 31 and the second transparent electrode layer 32. An example of a functional layer is one that contributes to the control of light transmittance. The functional layer that contributes to the control of light transmittance may be an alignment layer or a polarizing layer. The alignment layer may be placed between the first transparent electrode layer 34 and the photochromic layer 33, or between the second transparent electrode layer 32 and the photochromic layer 33. The polarizing layer may be placed between the first transparent support layer 35 and the first transparent electrode layer 34, or between the second transparent support layer 31 and the second transparent electrode layer 32. An example of a functional layer is one that enhances the strength and heat resistance of the photochromic sheet 30. The functional layer that enhances strength and heat resistance may be a hard coat layer. The hard coat layer may be placed on the lower surface of the first transparent support layer 35, or on the upper surface of the second transparent support layer 31. An example of a functional layer may be one that enhances the adhesion between layers within the photochromic sheet 30.

[0027] [First Flexible Wiring Board 40] The first flexible wiring board 40 electrically connects the first transparent electrode layer 34 to the drive unit 60. The first flexible wiring board 40 is an FPC (Flexible Printed Circuit) that applies a common voltage from the drive unit 60 to the first transparent electrode layer 34.

[0028] The first flexible printed circuit board 40 may be a double-sided FPC, a double-sided exposed FPC, a single-sided FPC, or a multilayer FPC. A double-sided FPC has wiring layers on both sides of an insulating base film, and a portion of each wiring layer is separately covered with a covering insulating film. A double-sided exposed FPC has a portion of both sides of a single wiring layer separately covered with a covering insulating film. A single-sided FPC has a wiring layer on one side of an insulating base film, and a portion of the wiring layer is covered with a single covering insulating film. A multilayer FPC has three or more wiring layers laminated with insulating films in between.

[0029] The following example shows a first flexible printed circuit board 40 that is a double-sided exposed FPC and has first terminals 43 on both the front and back surfaces of the first flexible printed circuit board 40. Alternatively, the first flexible printed circuit board 40 may be a single-sided FPC and have first terminals 43 on either the front or back surface of the first flexible printed circuit board 40.

[0030] As shown in Figure 3, the first flexible wiring board 40 has a strip shape extending in one direction. The first flexible wiring board 40 is bonded to the dimming sheet 30 such that the direction in which the first flexible wiring board 40 extends coincides with the first direction D1 in the dimming device 20.

[0031] The first flexible wiring board 40 is provided with a plurality of lead-outs that protrude in a direction intersecting the direction in which the first flexible wiring board 40 extends. The surface of the first flexible wiring board 40, i.e., the surface on the near side of the paper in Figure 1, is provided with one front-side first terminal 43 for each lead-out. The lead-outs may be arranged at a constant interval in the extending direction of the first flexible wiring board 40, or they may be arranged at different intervals from each other. The lead-outs may be unevenly distributed between the ends and the center in the extending direction of the first flexible wiring board 40. The number of lead-outs on the first flexible wiring board 40 is greater than the number of first wirings 61.

[0032] The surface of the first flexible wiring board 40 is covered by the first insulating film 41 on the front side, except for the first terminal 43 on the front side and one connecting portion 45, i.e., the connecting portion 45 on the upper side of the paper in Figure 1. The connecting portion 45 located on the upper side of the paper in Figure 1 is not covered by the first insulating film 41 on the front side and is therefore exposed to the outside. The first terminal 43 on the front side is supported around the periphery by the first insulating film 41 on the front side. As shown in Figure 1, in the dimming system 10, the first wiring 61 is connected to only one of the multiple first terminals 43. In the dimming system 10, among the multiple first terminals 43, the first terminal 43 located at the lower end of the first direction D1 may be connected to the first wiring 61. In the dimming system 10, among the multiple first terminals 43, the first terminal 43 located at the upper end may be connected to the first wiring 61, or the first terminal 43 located in the center may be connected to the first wiring 61. The position of the first terminal 43 connected to the first wiring 61 can be appropriately selected in the first direction D1 depending on the arrangement of the drive unit 60, the arrangement of the first wiring 61, the shape of the surrounding structure on which the dimming device 20 is mounted, and so on.

[0033] If the dimming system 10 includes a plurality of first wirings 61, the plurality of first terminals 43 include at least one first terminal 43 to which the first wiring 61 is not connected. In the dimming system 10, among the plurality of first terminals 43, two first terminals 43 located at the lower end and upper end of the first direction D1 may be connected to the first wiring 61, or two first terminals 43 located at the upper end and center may be connected to the first wiring 61. The positions of two or more first terminals 43 connected to the first wiring 61 are appropriately selected in the first direction D1 according to the arrangement of the drive unit 60, the arrangement of the first wiring 61, the shape of the surrounding structure on which the dimming device 20 is mounted, the magnitude of the potential gradient that may occur in the first direction D1, etc.

[0034] The first insulating film 41 on the front side may be a single-layer polyimide film, a multilayer polyimide film joined via an adhesive, a liquid crystal polymer film, a polyethylene terephthalate film, or an aramid cellulose ester film.

[0035] As shown in Figure 4, the first flexible wiring board 40 comprises a first insulating film 41 on the back side, i.e., the back side of the paper in Figure 1, one first electrode connection part 42, a plurality of parallel wirings 44, a first terminal 43 on the back side, and two connecting parts 45.

[0036] The first electrode connection portion 42 is exposed on the back surface of the first flexible wiring board 40, that is, on the back surface in Figure 1. The first electrode connection portion 42 has a strip shape that extends in the extending direction of the first flexible wiring board 40. The first electrode connection portion 42 has a comb-like shape that is repeated in the extending direction of the first flexible wiring board 40. The first electrode connection portion 42 is supported by the first insulating film 41 on the front side. The length of the first electrode connection portion 42 in the extending direction of the first flexible wiring board 40 is equal to the length of the first transparent electrode layer 34 in the first direction D1.

[0037] As shown in Figures 1 and 5, the first electrode connection portion 42 is electrically connected to the first end portion 34BE of the plurality of first divided electrodes 34B in the first transparent electrode layer 34 via the first conductive adhesive layer 47. The first conductive adhesive layer 47 is made of an anisotropic or isotropic conductive material.

[0038] Multiple parallel wirings 44 extend in a direction intersecting the direction in which the first flexible wiring board 40 extends from one first electrode connection part 42. Multiple parallel wirings 44 are connected in parallel to one first electrode connection part 42. Each parallel wiring 44 is located one at each lead-out part. Each parallel wiring 44 is sandwiched between a first insulating film 41 on the front side and a first insulating film 41 on the back side. The back surface of the first flexible wiring board 40 is provided with one first terminal 43 on the back side at each lead-out part. The first terminal 43 on the front side and the first terminal 43 on the back side are connected one to each parallel wiring 44. The first flexible wiring board 40 is provided with first terminals 43 as double-sided pads on both the front and back surfaces of the first flexible wiring board 40. In the dimming system 10, the first terminal 43 located on the front surface may be connected to the first wiring 61, or the first terminal 43 located on the back surface may be connected to the first wiring 61. Whether the first terminal 43 connected to the first wiring 61 is the first terminal 43 on the front surface or the first terminal 43 on the back surface can be appropriately selected in the first direction D1 depending on the arrangement of the drive unit 60, the arrangement of the first wiring 61, the shape of the surrounding structure on which the dimming device 20 is mounted, etc.

[0039] Returning to Figure 4, the connecting portion 45 is located at both ends in the extending direction of the first flexible wiring board 40. The connecting portion 45 is connected to the first electrode connection portion 42. The connecting portion 45 is a comb-tooth electrode connected to both ends of the first electrode connection portion 42. One of the connecting portion 45 is exposed on the back surface of the first flexible wiring board 40 and supported by the first insulating film 41 on the front side. The other connecting portion 45 is exposed on the front surface of the first flexible wiring board 40 and supported by the first insulating film 41 on the back side.

[0040] One connecting portion 45 of the first flexible wiring board 40 is configured to be electrically connected to the other connecting portion 45 of the other first flexible wiring board 40. In the two first flexible wiring boards 40 connected by their connecting portions 45, the first electrode connection portions 42 are electrically connected to each other.

[0041] The back surface of the first flexible wiring board 40 is covered with a first covering insulating film 41 on the back side, except for the first terminal 43, the first electrode connection portion 42, and one continuous portion 45 on the back side. The first covering insulating film 41 on the back side may cover the portion other than the first electrode connection portion 42 with an adhesive layer 41B on the back surface of the first flexible wiring board 40. The adhesive layer 41B attaches the first flexible wiring board 40 to the first transparent electrode layer 34.

[0042] The first covering insulating film 41 on the back side may be a single-layer polyimide film, a multi-layer polyimide film joined via an adhesive, a liquid crystal polymer film, a polyethylene terephthalate film, or an aramid cellulose ester film.

[0043] The first electrode connection portion 42, the first terminal 43, and the parallel wiring 44 may be formed from one copper foil or one aluminum foil. The copper foil may be a rolled copper foil or an electrolytic copper foil. The aluminum foil may be a rolled aluminum foil or an electrolytic aluminum foil.

[0044] The first flexible wiring board 40 may include a vulnerable portion 47B at the lead-out portion. The vulnerable portion 47B may be disposed at the base end portion of the lead-out portion. The vulnerable portion 47B is located between the first electrode connection portion 42 and the first terminal 43 and is configured to disconnect the first terminal 43 from the first electrode connection portion 42. The vulnerable portion 47B may be a notch disposed in at least one of the first covering insulating film 41 on the front side and the first covering insulating film 41 on the back side. The vulnerable portion 47B may be a perforated line disposed in at least one of the first covering insulating film 41 on the front side and the first covering insulating film 41 on the back side.

[0045] As shown in FIG. 5, the dimming device 20 may include a first sealing portion 46 so as to cover the first transparent electrode layer 34 and the first flexible wiring board 40 at a portion where the first flexible wiring board 40 is connected to the first transparent electrode layer 34. The first sealing portion 46 covers the end face of the dimming layer 33. The first sealing portion 46 reinforces the connection between the first transparent electrode layer 34 and the first flexible wiring board 40.

[0046] [Second Flexible Wiring Substrate 50] Returning to FIG. 1, the second flexible wiring substrate 50 electrically connects the second divided electrode 32B to the drive unit 60. The second flexible wiring substrate 50 is an FPC that applies a control voltage from the drive unit 60 to the second divided electrode 32B.

[0047] The second flexible wiring substrate 50 may be a double-sided FPC, a double-sided exposed FPC, a single-sided FPC, or a multilayer FPC. Hereinafter, an example in which the second flexible wiring substrate 50 is a single-sided FPC and includes a second terminal 53 on the surface of the second flexible wiring substrate 50 will be shown. Note that the second flexible wiring substrate 50 may be a double-sided FPC or a double-sided exposed FPC and may include the second terminal 53 on the front and back surfaces of the second flexible wiring substrate 50.

[0048] The second flexible wiring substrate 50 includes one second electrode connection portion 52 and one second terminal 53. The second electrode connection portion 52 has a comb shape arranged in the first direction D1. The second electrode connection portion 52 is electrically connected to the second terminal 53. The surface of the second flexible wiring substrate 50, that is, the front side of the paper surface of FIG. 1, exposes one second terminal 53. The second flexible wiring substrate 50 includes one second terminal 53 in one second electrode connection portion 52. In the direction in which the teeth of the second electrode connection portion 52 are arranged, the length of the second electrode connection portion 52 may be equal to the length of the second divided electrode 32B. In the direction in which the teeth of the second electrode connection portion 52 are arranged, the length of the second electrode connection portion 52 may be less than the length of the second divided electrode 32B.

[0049] As shown in FIGS. 1 and 6, the second flexible wiring substrate 50 includes a front-side, that is, a second covering insulating film 51 on the front side of the paper surface of FIG. 1, a back-side, that is, a second covering insulating film 51 on the back side of the paper surface of FIG. 1, one second electrode connection portion 52, and a second terminal 53. The second electrode connection portion 52 is electrically connected to the second terminal 53.

[0050] The second electrode connection portion 52 is supported by the back-side second covering insulating film 51. The second electrode connection portion 52 is connected to a second end portion 32BE of one second divided electrode 32B in the second transparent electrode layer 32 via a second conductive adhesive layer 57. The second conductive adhesive layer 57 is made of an anisotropic or isotropic conductive material.

[0051] The second electrode connection portion 52 and the second terminal 53 are supported on the front side of the second flexible wiring board 50 by the second insulating film 51 on the front side. The second electrode connection portion 52 is also supported on the back side of the second insulating film 51 on the back side of the second flexible wiring board 50.

[0052] The second electrode connection portion 52 and the second terminal 53 may be formed from a single copper foil or from a single aluminum foil. The copper foil may be rolled copper foil or electrolytic copper foil. The aluminum foil may be rolled aluminum foil or electrolytic aluminum foil.

[0053] The dimming device 20 may be provided with a second sealing portion 56 that covers the second transparent electrode layer 32 and the second flexible wiring board 50 at the portion where the second transparent electrode layer 32 connects to the second flexible wiring board 50. The second sealing portion 56 covers the end face of the dimming layer 33. The second sealing portion 56 reinforces the connection between the first divided electrode 34B and the second flexible wiring board 50.

[0054] [Operation] As described above, the first wiring 61 connected to the drive unit 60 of the dimming layer 33 supplies power to the first transparent electrode layer 34 through the first terminal 43 of the first flexible wiring board 40. The first wiring 61 is connected to one of the first terminals 43 connected in parallel to the first electrode connection unit 42. The common voltage applied to the multiple first terminals 43 is applied to all the first divided electrodes 34B through the first electrode connection unit 42. Then, according to the control voltage applied to each second terminal 53, the dimming layer 33 sandwiched between the first divided electrode 34B and the second divided electrode 32B is driven for each second divided electrode 32B.

[0055] As shown in Figure 7, in the dimming system 10, some of the parallel wirings 44 among the plurality of parallel wirings 44 are electrically connected to the first wiring 61. Here, the other parallel wirings 44 among the plurality of parallel wirings 44 may be cut at the weak point 47B together with the first insulating film 41 so that they are shorter than the parallel wirings 44 to which the first wiring 61 is connected. In this case, the parallel wirings 44 not connected to the first wiring 61, and the first insulating film 41 covering the parallel wirings 44, constitute a cut mark 49 where the lead portion is separated from the first flexible wiring board 40. The cut mark 49 may be covered with a sealing material to protect the parallel wirings 44 from the outside air. Note that the separation of the lead portion may be performed on the first flexible wiring board 40 after it has been connected to the first transparent electrode layer 34, or on the first flexible wiring board 40 before it has been connected to the first transparent electrode layer 34.

[0056] [Effects] As explained above, the following effects can be obtained: (1) The degree of freedom in the first direction D1 is increased by the number of first terminals 43 regarding the arrangement of the first wiring 61. As a result, the mounting burden of the first wiring 61 to adapt the wiring arrangement to the specifications of the dimming device 20 is reduced.

[0057] (2) Multiple first divided electrodes 34B are connected in parallel to the first electrode connection part 42. One second electrode connection part 52 is connected to each second divided electrode 32B. Therefore, even if the first wiring 61 is connected to only some of the multiple first terminals 43, a common voltage can be applied to the multiple first divided electrodes 34B. Then, the dimming layer 33 sandwiched between the first divided electrode 34B and the second divided electrode 32B is driven for each second divided electrode 32B.

[0058] (3) It is possible to superimpose the second insulating portion 32A onto the first insulating portion 34A in the thickness direction of the dimming layer 33. The process of superimposing the second insulating portion 32A onto the first insulating portion 34A is performed, for example, by irradiating the second transparent electrode layer 32 through the first transparent electrode layer 34 and the dimming layer 33 with a laser that insulates the first transparent electrode layer 34. When the thickness of the dimming layer 33 is a thin film of 100 μm or less, the process of irradiating the first transparent electrode layer 34 and the second transparent electrode layer 32 with a laser makes it easy to superimpose the second insulating portion 32A onto the first insulating portion 34A. For this reason, in a dimming device 20 in which the processing load of the first divided electrode 34B and the second divided electrode 32B is reduced, the mounting load of the first wiring 61 that adapts the wiring arrangement to the specifications of the dimming device 20 is reduced.

[0059] (4) Since multiple first terminals 43 are arranged along the first direction D1, a group of first terminals 43 for applying a common voltage is easily identified by sight. For this reason, it is easy to understand during wiring installation work that a common voltage can be applied to multiple first divided electrodes 34B by connecting the first wiring 61 to any of the group of first terminals 43.

[0060] (5) A common voltage is applied from the first end 34BE of the first divided electrode 34B. A control voltage is applied from the second end 32BE of the second divided electrode 32B. As a result, the voltage applied between the first divided electrode 34B and the second divided electrode 32B is made uniform in the second direction D2.

[0061] (6) The first flexible wiring board 40 is equipped with double-sided pads including the first terminals 43 on the front side and the first terminals 43 on the back side. In this case, the degree of freedom in arranging the first wiring 61 is increased on the front and back sides of the first flexible wiring board 40.

[0062] (7) When the end of the first flexible wiring board 40 is provided with a connecting portion 45, the two first flexible wiring boards 40 are electrically connected at their ends. This allows the length of the first flexible wiring board 40, and consequently the length of the dimming device 20 driven by the drive unit 60, to be increased. (8) Among the plurality of first terminals 43, the first terminals 43 that are not connected to the first wiring 61 are disconnected by the fragile portion 47B. This reduces the wiring mounting load required to adapt the wiring arrangement to the specifications of the dimming device 20, while also reducing the size of the first flexible wiring board 40.

[0063] The above-described embodiment can be implemented with the following modifications: • Parallel wiring 44 not connected to the first wiring 61 may remain in the dimming system 10 without being disconnected from the first flexible wiring board 40. The vulnerable portion 47B for disconnecting the parallel wiring 44 may be omitted from the first flexible wiring board 40. The first terminal 43 not connected to the first wiring 61 may be covered with a sealing material to prevent contact with the outside.

[0064] - The connecting portion 45 may be omitted from the first flexible wiring board 40. The first flexible wiring board 40 may be longer than the length of the dimming sheet 30 in the first direction D1. In this case, the first flexible wiring board 40 may be cut in the middle of the first direction D1 so as to assign one or more first terminals 43 to the dimming sheet 30.

[0065] - The first flexible wiring board 40 may have a single-sided pad on at least one of the plurality of first terminals 43. - The second flexible wiring board 50 may have two or more second terminals 53 connected in parallel to one second electrode connection portion 52. The second terminals 53 may have double-sided pads. In this configuration as well, the effects similar to those described in (1) to (7) above can be obtained.

[0066] The first insulating portion 34A and the second insulating portion 32A may be composed of multiple line segments extending in mutually different directions. An example of a shape composed of multiple line segments extending in mutually different directions is an L-shape. In this case, the direction in which the first divided electrode 34B and the second divided electrode 32B are aligned may be in a direction that intersects with each line segment constituting the first insulating portion 34A and the second insulating portion 32A, or it may be parallel to the direction in which one line segment extends. The direction in which the first terminals 43 are aligned may be parallel to the direction in which the first divided electrode 34B and the second divided electrode 32B are aligned, or it may be in a direction that intersects with it. The direction in which the first terminals 43 are aligned may be in multiple directions that include the direction in which each line segment extends.

Claims

1. A dimming device comprising: a pair of transparent electrode layers composed of a first transparent electrode layer and a second transparent electrode layer; a dimming layer disposed between the first transparent electrode layer and the second transparent electrode layer; and a flexible wiring board connected to the first transparent electrode layer, wherein each transparent electrode layer is provided with a plurality of divided electrodes electrically separated by an insulating portion; and the flexible wiring board is provided with an electrode connection portion connected to the divided electrodes of the first transparent electrode layer; and a plurality of terminals connected in parallel to the electrode connection portion for connecting the electrode connection portion to a drive portion that drives the dimming layer.

2. The dimming device according to claim 1, wherein the plurality of divided electrodes are arranged along a first direction, the electrode connection portion is a first electrode connection portion extending in the first direction, and the plurality of divided electrodes constituting the first transparent electrode layer are connected in parallel to the first electrode connection portion, and further comprises a plurality of second electrode connection portions, one each connected to the divided electrodes constituting the second transparent electrode layer.

3. The dimming device according to claim 2, wherein the first transparent electrode layer comprises a first insulating portion and a plurality of first divided electrodes insulated from each other by the first insulating portion, and the second transparent electrode layer comprises a second insulating portion that overlaps the first insulating portion in the thickness direction of the dimming layer and a plurality of second divided electrodes insulated from each other by the second insulating portion.

4. The dimming device according to any one of claims 1 to 3, wherein the plurality of divided electrodes are arranged along a first direction, the electrode connection portion extends in the first direction, and the plurality of divided electrodes constituting the first transparent electrode layer are connected in parallel to the electrode connection portion, and the plurality of terminals are arranged along the first direction.

5. The dimming device according to claim 2, wherein the divided electrode extends in a second direction intersecting the first direction from the second end to the first end, the first ends of a plurality of the divided electrodes in the first transparent electrode layer are connected in parallel to the first electrode connection portion, and the second electrode connection portion is connected one by one to the second ends of the divided electrodes in the second transparent electrode layer.

6. The dimming device according to claim 4, wherein the plurality of terminals are arranged at regular intervals along the first direction.

7. The dimming device according to any one of claims 1 to 3, wherein the terminal is a double-sided pad.

8. The dimming device according to any one of claims 1 to 3, wherein the end of the flexible wiring board is connected to the electrode connection portion and has a connecting portion that is exposed to the outside, and the connecting portion is configured to be electrically connected to the connecting portion of another flexible wiring board.

9. A dimming device according to any one of claims 1 to 3, comprising an insulating film supporting the electrode connection portion and the terminal, wherein the insulating film has a weak portion between the electrode connection portion and the terminal for separating the terminal from the electrode connection portion.

10. A dimming system comprising: a pair of transparent electrode layers comprising a first transparent electrode layer and a second transparent electrode layer; a dimming layer disposed between the first transparent electrode layer and the second transparent electrode layer; a flexible wiring board electrically connected to the first transparent electrode layer; a drive unit for driving the dimming layer; and wiring electrically connecting the flexible wiring board to the drive unit, wherein each transparent electrode layer comprises a plurality of divided electrodes electrically separated by an insulating portion; the flexible wiring board comprises: an electrode connection portion electrically connected to the first transparent electrode layer; a plurality of parallel wirings connected in parallel to the electrode connection portion and extending from the electrode connection portion; and an insulating film supporting the electrode connection portion and the parallel wiring, wherein a portion of the plurality of parallel wirings is connected to a terminal for connecting the electrode connection portion to the drive unit; and the other portion of the plurality of parallel wirings forms a cut mark, which is cut together with the insulating film to be shorter than the portion.

11. A flexible wiring board connected to a dimming sheet, wherein the dimming sheet comprises a pair of transparent electrode layers composed of a first transparent electrode layer and a second transparent electrode layer, and a dimming layer disposed between the first transparent electrode layer and the second transparent electrode layer, each of the transparent electrode layers comprises a plurality of divided electrodes electrically separated by an insulating portion, and the flexible wiring board comprises a single electrode connection portion extending in the direction in which the divided electrodes of the first transparent electrode layer are aligned and having comb teeth aligned in that direction, thereby connecting the plurality of divided electrodes in parallel, and a plurality of terminals connected in parallel to the electrode connection portion and arranged at a constant interval along that direction, characterized in that the flexible wiring board.

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