Dimming device

Abstract

To make a dimming device thinner.SOLUTION: A dimming device D includes a pair of movable rollers 20 arranged in a spaced-apart fashion from each other in a direction orthogonal to the front and back direction, and a loop-shaped polarizing film 22 stretched over both the movable rollers 20. The polarizing film 22 has a first polarizing section 23 and a second polarizing section 24, which respectively have polarizing axes and face each other in the front and back direction, between both the movable rollers 20. The first polarizing section 23 is positioned in front of the second polarizing section 24. A transparent sheet 31 having higher rigidity than the polarizing film 22 is arranged between both the movable rollers 20 and in front of the first polarizing section 23. The first polarizing section 23 has a portion adjacent to the second polarizing section 24 and the sheet 31. A tension roller 36, which applies tension by pressing the polarizing film 22 toward the side where the first polarizing section 23 approaches the second polarizing section 24, is arranged between the movable rollers 20 and the sheet 31 and in front of the first polarizing section 23.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light control device. [Background technology]

[0002] A light control device is known that adjusts the degree of light transmission by utilizing the optical properties of polarized light. Here, the direction in which the light control device faces the user is referred to as the front-rear direction. In the front-rear direction, the side closer to the user is referred to as the front side, and the side farther from the user is referred to as the rear side.

[0003] Patent Document 1, for example, describes a dimming device that includes a pair of movable rollers spaced apart from each other in a direction perpendicular to the front-to-rear direction, and a loop-shaped polarizing film stretched across the pair of movable rollers.

[0004] The polarizing film has a first polarizing section and a second polarizing section, each having a polarization axis and facing each other in the front-rear direction, between a pair of movable rollers. In the light control device, the first and second polarization sections move in opposite directions along the direction in which the pair of movable rollers are arranged, as the pair of movable rollers rotate, adjusting the degree of light transmission through the first and second polarization sections.

[0005] The light control device further includes two pairs of pressure rollers (tension rollers). The pressure rollers are provided at two locations between the movable rollers in the arrangement direction, close to each movable roller. The two pressure rollers in each pair are arranged on both sides of the first polarizing unit and the second polarizing unit in the front-to-back direction. The two pressure rollers in each pair press the first polarizing unit and the second polarizing unit inward in the front-to-back direction, thereby applying tension to the polarizing film and narrowing the distance between the first polarizing unit and the second polarizing unit in the front-to-back direction. This is because if the distance is too large, it becomes difficult for the light control device to effectively exhibit its light control function. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 10-61351 Summary of the Invention [Problem to be solved by the invention]

[0007] However, as described above, the light control device described in Patent Document 1 uses a pair of pressure rollers. The two pressure rollers in each pair are arranged side by side in the front-to-rear direction. This increases the dimensions of the light control device in the front-to-rear direction. As a result, for example, when the light control device is installed next to a window indoors, the amount of protrusion of the light control device from the window toward the interior of the room increases. This makes it difficult to install the light control device. [Means for solving the problem]

[0008] Various aspects of the light control device for solving the above problems will be described below. [Aspect 1] When the direction facing the user is defined as the front-to-rear direction, and the side closer to the user in the front-to-rear direction is defined as the front side, and the side farther from the user in the front-to-rear direction is defined as the rear side, the device comprises a pair of movable rollers arranged parallel to and spaced apart from each other in a direction perpendicular to the front-to-rear direction, and a loop-shaped polarizing film stretched across the pair of movable rollers, the polarizing film having a first polarizing section and a second polarizing section each having a polarization axis and facing each other in the front-to-rear direction, between the pair of movable rollers, the first polarizing section being located in front of the second polarizing section, and the first polarizing section and the second polarizing section moving in a direction parallel to and spaced from each other in a direction perpendicular to the front-to-rear direction, the polarizing film having a first polarizing axis and a second polarizing section facing each other in the front-to-rear direction, the first polarizing section being located in front of the second polarizing section, and the first polarizing section and the second polarizing section being moved in a direction parallel to and spaced from each other in a direction perpendicular to the front-to-rear direction, the polarizing film having a first polarizing axis and a second polarizing section facing each other in the front-to-rear direction, the first polarizing section being located in front of the second polarizing section, and the first polarizing section being moved in a direction parallel to and spaced from the pair of movable rollers as the pair of movable rollers rotate. a light control device that adjusts the degree of light transmission in the first polarization unit and the second polarization unit by moving in opposite directions along a placement direction, wherein a transparent sheet having higher rigidity than the polarizing film is disposed between the pair of movable rollers and in front of the first polarization unit, the first polarization unit having a portion adjacent to the second polarization unit and the sheet, and a tension roller that applies tension to the polarizing film by pressing the polarizing film toward a side that brings the first polarization unit closer to the second polarization unit is disposed between at least one of the movable rollers and the sheet and in front of the first polarization unit.

[0009] According to the above configuration, the second polarization unit is located between the pair of movable rollers, and the first polarization unit is located in front of the second polarization unit between the pair of movable rollers. The tension roller presses the polarizing film toward the side that brings the first polarizing unit closer to the second polarizing unit. This pressing narrows the distance between the first polarizing unit and the second polarizing unit in the front-to-rear direction. The tension roller also applies tension to the polarizing film by pressing the polarizing film. This tension maintains the narrow distance between the first polarizing unit and the second polarizing unit.

[0010] Furthermore, when the first polarization unit comes into contact with the rear surface of the sheet, the sheet restricts the forward movement of the first polarization unit and the second polarization unit. The sheet also performs this restriction with its own wide rear surface. Therefore, a significant effect can be obtained in restricting the movement.

[0011] As a result, the narrow gap between the first polarization unit and the second polarization unit is more easily maintained. To maintain this narrow gap, it is no longer necessary to use a tension roller that presses the second polarization unit forward. The reduced number of tension rollers reduces the dimensions of the light control device in the front-to-back direction. Furthermore, the light control device is lighter.

[0012] Polarizing films are prone to wrinkling due to environmental changes, such as shrinkage caused by drying and expansion caused by water absorption. However, as described above, tension is applied to the polarizing film by the tension roller. Therefore, even if the environment changes, the polarizing film is less likely to wrinkle. This prevents deterioration of display quality due to wrinkles.

[0013] [Aspect 2] A light control device according to [Aspect 1], wherein the rear surface of the sheet is located at the same location or an adjacent location in the front-to-rear direction relative to the rear ends of the outer peripheral surfaces of each of the pair of movable rollers.

[0014] According to the above configuration, the second polarization unit is located between the pair of movable rollers and between the rear ends of the outer peripheral surfaces. The second polarization unit is parallel or nearly parallel to the rear surface of the sheet. The first polarization unit is between the sheet and the second polarization unit and is parallel or nearly parallel to the second polarization unit and the sheet. The distance between the first polarization unit and the second polarization unit in the front-to-rear direction is maintained at a small value.

[0015] [Aspect 3] The tension roller applies tension to the polarizing film by pressing the portion of the polarizing film between the movable roller and the sheet toward the movable roller, and the rear end of the outer surface of the tension roller is located at the same location or an adjacent location in the front-to-back direction relative to the rear surface of the sheet. This is a light control device described in [Aspect 2].

[0016] If a tension roller is not provided or if the rear end of the tension roller's outer circumferential surface is located forward of the rear surface of the sheet, the following concern arises: If a tension roller is not provided, the portion of the polarizing film between the movable roller and the sheet will be inclined with respect to the rear surface of the sheet. Furthermore, if the rear end of the tension roller's outer circumferential surface is located forward of the rear surface of the sheet, the portion of the polarizing film between the tension roller and the sheet will be inclined with respect to the rear surface of the sheet. In either case, this portion of the polarizing film moves while being pressed against the corner between the rear surface and the edge of the sheet in the arrangement direction. Friction between the corner and the polarizing film may wear out, reducing its durability.

[0017] In this regard, the above configuration provides a tension roller. Furthermore, the rear end of the outer peripheral surface of the tension roller and the rear surface of the sheet are located at the same or adjacent positions in the front-to-rear direction. Therefore, the portion of the polarizing film between the tension roller and the sheet is parallel or nearly parallel to the rear surface of the sheet. This portion of the polarizing film is less likely to move while being pressed against the corner of the sheet. As a result, the deterioration of the durability of the polarizing film due to the friction is suppressed.

[0018] [Embodiment 4] A light control device according to any one of [Embodiment 1] to [Embodiment 3], further comprising a frame having a pair of main frame portions, wherein the movable roller is rotatably supported within each main frame portion and an end of the sheet in the arrangement direction is inserted within the main frame portion, and a portion of the polarizing film is located behind the end of the sheet within each main frame portion, and at least one of the main frame portions is provided behind the portion of the polarizing film that is located behind the end of the sheet within the main frame portion and has a protrusion that protrudes forward.

[0019] According to the above configuration, when the second polarizing unit comes into contact with the protrusion, the protrusion restricts the rearward movement of the first polarizing unit and the second polarizing unit. The first polarizing unit and the second polarizing unit are sandwiched from both sides in the front-to-rear direction by the end of the sheet and the protrusion within the main frame, and movement in the same direction is restricted within the main frame. This further improves the accuracy of the spacing between the first polarizing unit and the second polarizing unit in the front-to-rear direction.

[0020] [Embodiment 5] A dimming device that uses a polarizing film having a pair of polarizing sections, each with a polarization axis and facing each other in the front-to-back direction when the direction facing the user is the front-to-back direction, and that adjusts the degree of light transmission through the pair of polarizing sections by moving the pair of polarizing sections in opposite directions along a direction perpendicular to the front-to-back direction, wherein a frame is provided around the periphery of the pair of polarizing sections, and outside the frame the spacing between the pair of polarizing sections is 1 mm or less.

[0021] According to the above configuration, the distance between the pair of polarizing sections of the polarizing film outside the frame affects the front-to-rear dimension of the light control device, particularly the front-to-rear dimension outside the frame. The smaller the distance outside the frame, the smaller the effect. In this regard, by setting the distance between the pair of polarizing sections to 1 mm or less outside the frame as in the above configuration, the effect is reduced. This makes it possible to reduce the thickness of the light control device outside the frame, and ultimately the entire light control device. [Effects of the Invention]

[0022] According to the present invention, it is possible to reduce the thickness of the light control device. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 1 is a diagram showing a light control device according to one embodiment, and is a partial cross-sectional view taken along line 1-1 in FIG. [Figure 2] FIG. 2 is a perspective view of the light control device according to the embodiment. [Figure 3]FIG. 3 is an exploded perspective view showing the layer structure of the first polarizing unit in the same embodiment. [Figure 4] FIG. 4 is an exploded perspective view showing the layer structure of the second polarizing unit in the same embodiment. [Figure 5] FIG. 5 is a partial cross-sectional view showing the layer structure of the polarizing region in the same embodiment. [Figure 6] FIG. 6 is an explanatory diagram showing a pattern of polarization axes in the polarization region of the embodiment. [Figure 7] Figure 7(A) is an explanatory diagram showing the effect of a first polarizing layer with a narrow gap between it and the second polarizing layer when viewed from diagonally above the front, and Figure 7(B) is an explanatory diagram showing the effect of a first polarizing layer with a wide gap between it and the second polarizing layer when viewed from diagonally above the front. [Figure 8] FIG. 8 is a diagram corresponding to FIG. 6, and is an explanatory diagram showing an example of a modified pattern of the polarization axes in the polarization region portion. [Figure 9] FIG. 9 is an explanatory diagram showing a modified example of the pattern of the polarization axes in the polarization region portion, which is different from that shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0024] An embodiment of the light control device D will be described below with reference to FIGS. In the following description, the direction of the dimming device D facing the user U is referred to as the front-to-rear direction. In the front-to-rear direction, the side closer to the user U is referred to as the front side, and the side farther from the user U is referred to as the rear side. The vertical direction is referred to as the up-down direction. The direction perpendicular to the front-to-rear direction and the up-down direction is referred to as the left-to-right direction.

[0025] 1 and 2, the light control device D includes a frame 9, a movable roller 20, a polarizing film 22, a sheet 31, and a tension roller 36. Next, each part constituting the light control device D will be described.

[0026] <Frame 9> The frame 9 is provided on the periphery of both the first polarization section 23 and the second polarization section 24, which will be described later. The frame 9 includes a front frame component 11 and a rear frame component 13, each of which has a rectangular frame shape. The rear frame component 13 is disposed on the rear side of the front frame component 11, and is connected to the front frame component 11 by a fastening member (not shown) or the like.

[0027] The frame 9 comprises a pair of main frame portions 16 extending parallel to the left and right directions and spaced apart from each other in the vertical direction, and a pair of connecting frame portions 19 extending parallel to the up and down directions and spaced apart from each other in the horizontal direction.

[0028] The pair of main frame portions 16 have shapes that are line-symmetrical to each other in the up-down direction, and the pair of connecting frame portions 19 have shapes that are line-symmetrical to each other in the left-right direction. Here, in the vertical and horizontal directions, the center of the space S surrounded by the frame 9 is used as the reference, and the side closer to this center is sometimes referred to as the "inside" or "inner side," and the side away from the center is sometimes referred to as the "outside" or "outer side."

[0029] As shown in Figure 1, a main storage section 17 extending in the left-right direction is formed inside each main frame section 16. The outer end of each main storage section 17 in the up-down direction is closed, and the inner end is open. If this open portion is referred to as an inner end open section 18, each main storage section 17 communicates with the space S through the inner end open section 18. Each main storage section 17 is made up of front recesses 12 formed in the upper and lower parts of the front frame component 11, respectively, and rear recesses 14 formed in the upper and lower parts of the rear frame component 13, respectively, and located rearward of each front recess 12.

[0030] 2, a connecting housing portion (not shown) extending in the up-down direction is formed in the inner portion in the left-right direction of each connecting frame portion 19. The outer end of each connecting housing portion in the left-right direction is closed, and the inner end is open. Each connecting frame portion 19 communicates with the space S through the open portion of the inner end.

[0031] The front surface 10 of the frame 9 configured as above constitutes a part of the design surface of the light control device D. <Movable roller 20> 1, a pair of cylindrical movable rollers are used as the movable rollers 20. Each movable roller 20 has a shaft (not shown) having an axis L1 extending in the left-right direction.

[0032] Each movable roller 20 is disposed at the outer side of each main housing section 17 in the vertical direction. Therefore, the movable rollers 20 are disposed spaced apart from each other in the vertical direction, which is one aspect of a direction perpendicular to the front-to-rear direction. Each movable roller 20 is rotatably supported by a shaft on the corresponding main frame section 16.

[0033] <Polarizing film 22> The polarizing film 22 is flexible and loop-shaped (endless). The polarizing film 22 is stretched across a pair of movable rollers 20. The polarizing film 22 has a first polarizing section 23 and a second polarizing section 24, which face each other in the thickness direction of the polarizing film 22, between the pair of movable rollers 20. The first polarizing section 23 is located in front of the second polarizing section 24. Here, the thickness directions of the first polarizing section 23 and the second polarizing section 24 coincide with the front-rear direction.

[0034] The polarizing film 22 further includes a connecting portion 25 that connects the upper ends of the first polarizing portion 23 and the second polarizing portion 24, and a connecting portion 25 that connects the lower ends of the first polarizing portion 23 and the second polarizing portion 24. The polarizing film 22 is stretched across a pair of movable rollers 20 at both connecting portions 25.

[0035] The second polarization sections 24 are located at the same position or adjacent positions in the front-rear direction on the rear ends 21a of the outer circumferential surfaces 21 of the pair of movable rollers 20, respectively. As shown in FIGS. 3 and 4, the first polarizing section 23, the second polarizing section 24, and the connecting section 25 of the polarizing film 22 have a loop-shaped film substrate 27 as a common component.

[0036] The film substrate 27 is made of a transparent thermoplastic resin and has flexibility, such as PET (polyethylene terephthalate) resin, PE (polyethylene) resin, PP (polypropylene) resin, ABS (acrylonitrile-butadiene-styrene copolymer) resin, PVA (polyvinyl alcohol) resin, and TAC (triacetyl cellulose) resin.

[0037] Each of the first polarization unit 23 and the second polarization unit 24 includes two types of strip-shaped polarization regions in addition to the film substrate 27. Both polarization regions are bonded to one surface of the film substrate 27 in the front-to-rear direction. The polarization regions are formed on the inner peripheral surface of the loop-shaped film substrate 27. In the first polarization unit 23, the polarization region is formed on the rear surface of the film substrate 27. In the second polarization unit 24, the polarization region is formed on the front surface of the film substrate 27.

[0038] Herein, when it is necessary to distinguish between the two types of polarizing regions, one will be referred to as a first polarizing region A1 and the other as a second polarizing region A2. In Figures 3 and 4, to distinguish between the first polarizing region A1 and the second polarizing region A2 and make them easier to see, only the former is dotted. Each of the first polarizing section 23 and the second polarizing section 24 is provided with a plurality of first polarizing region A1 and a plurality of second polarizing region A2.

[0039] In contrast, both connecting sections 25 are configured only by the film substrate 27. However, like the first polarizing section 23 and the second polarizing section 24, both connecting sections 25 may have a layer structure including the film substrate 27 and the first polarizing region A1 and the second polarizing region A2 formed thereon.

[0040] 5, each of the first polarizing region A1 and the second polarizing region A2 includes a film body 28 and a pair of transparent protective films 29 that sandwich the film body 28 from both sides in the front-to-rear direction. Like the film substrate 27, the first polarizing region A1 and the second polarizing region A2 are flexible.

[0041] The film body 28 is formed, for example, from PVA resin dyed with an iodine solution. The film body 28 is produced, for example, as follows: A PVA resin film is dyed with iodine. The PVA resin molecules that make up the film are bonded together with boric acid and stabilized. The film is stretched in one direction while still wet. The PVA resin molecules and iodine molecules align in the stretched direction. When this film is dried, the film body 28 is obtained, which has a polarization axis and exhibits polarization properties.

[0042] Each protective film 29 is intended to protect the film main body 28 from external impact, heat, humidity, etc. Each protective film 29 is made of an optically isotropic material, such as TAC resin. Each protective film 29 is attached to the film main body 28.

[0043] 3, 4, and 6, each of the first polarizing regions A1 and each of the second polarizing regions A2 is strip-shaped and has a longer horizontal dimension than its vertical dimension. The vertical dimensions of the first polarizing region A1 and the second polarizing region A2 are set to be the same. The first polarizing region A1 and the second polarizing region A2 are alternately arranged in the vertical direction and are bonded to the film substrate 27 by adhesive.

[0044] In addition, when it is necessary to distinguish between the layer consisting of the polarizing area portions A1 and A2 in the first polarizing section 23 and the layer consisting of the polarizing area portions A1 and A2 in the second polarizing section 24, the former may be referred to as the first polarizing layer 23a and the latter as the second polarizing layer 24a.

[0045] As described above, the first polarizing section 23 and the second polarizing section 24 have a configuration in which the first polarizing region A1 and the second polarizing region A2 are bonded to the film substrate 27. This may cause undulations or unevenness in the first polarizing section 23 and the second polarizing section 24. Therefore, when we talk about the spacing between the first polarizing section 23 and the second polarizing section 24, we mean the average spacing between the surface of the first polarizing section 23 facing the second polarizing section 24 (the rear surface of the first polarizing layer 23a) and the surface of the second polarizing section 24 facing the first polarizing section 23 (the front surface of the second polarizing layer 24a).

[0046] Each first polarizing region A1 has a first polarization axis PA1, and each second polarizing region A2 has a second polarization axis PA2 extending in a direction different from the first polarization axis PA1. In this embodiment, the first polarizing region A1 has the first polarization axis PA1 extending in a direction parallel to its length direction (the horizontal direction in FIG. 6). The second polarizing region A2 has the second polarization axis PA2 extending in a direction (the vertical direction) perpendicular to its length direction (the horizontal direction in FIG. 6).

[0047] Note that a layer for adding functionality may be added to the polarizing film 22. For example, a low-friction layer may be formed on the inner peripheral surface of the loop-shaped polarizing film 22. The low-friction layer is provided for the purpose of increasing slipperiness, for example, increasing the sliding ability of one of the first polarizing section 23 and the second polarizing section 24 relative to the other, increasing water repellency, etc. The low-friction layer is formed by subjecting the inner peripheral surface of the loop-shaped polarizing film 22 to a lubricant treatment, such as a water-repellent coating treatment or a silicone coating treatment.

[0048] Furthermore, a hard coat layer may be formed on the outer peripheral surface of the loop-shaped polarizing film 22. The hard coat layer provides useful effects to the layer that constitutes the polarizing film 22 on which the hard coat layer is formed, such as preventing scratches, making the layer less susceptible to dirt, improving light resistance and weather resistance by blocking ultraviolet rays, and providing water repellency.

[0049] <Sheet 31> 1, the sheet 31 is formed in a rectangular flat plate shape from a transparent material that is more rigid than the polarizing film 22. Examples of such materials include inorganic glass and resin glass (organic glass). As the resin glass, commonly known resin materials such as polycarbonate (PC) resin and polymethyl methacrylate (PMMA) resin can be used.

[0050] In the front-rear direction, the sheet 31 is disposed adjacent to the front side of the first polarization unit 23. In this embodiment, the rear surface 33 of the sheet 31 is located at the same position as or adjacent to the rear ends 21 a of the outer peripheral surfaces 21 of the pair of movable rollers 20 in the front-rear direction.

[0051] The sheet 31 is disposed in a position between the pair of movable rollers 20 in the vertical direction. The upper end 31a of the sheet 31 enters the lower part of the upper main storage section 17 through the inner end open section 18 of the upper main frame section 16. The lower end 31a of the sheet 31 enters the upper part of the lower main storage section 17 through the inner end open section 18 of the lower main frame section 16. The left and right side sections of the sheet 31 enter the connecting storage sections of the connecting frame section 19.

[0052] The sheet 31 is fixed to the frame 9 with a portion thereof inserted into both main frame portions 16 and both connecting frame portions 19 as described above. The front surface 32 of the sheet 31 configured as above constitutes a part of the design surface of the light control device D.

[0053] <Tension roller 36> A pair of cylindrical tension rollers are used as the tension rollers 36. Each tension roller 36 is provided with a shaft (not shown) having an axis L2 extending in the left-right direction.

[0054] Each tension roller 36 is disposed in the corresponding main storage section 17 between the movable roller 20 and the end 31a of the sheet 31. In the front-rear direction, each tension roller 36 is disposed adjacent to the front side of the first polarization section 23.

[0055] Each tension roller 36 is provided to apply tension to the polarizing film 22 by pressing the polarizing film 22 toward the side that brings the first polarizing unit 23 closer to the second polarizing unit 24. To achieve this purpose, each tension roller 36 is biased outward in the vertical direction by an elastic body (not shown) such as a spring. In this embodiment, a tension coil spring that pulls the tension roller 36 toward the movable roller 20 is used as the elastic body. Each biased tension roller 36 applies tension to the polarizing film 22 by pressing a portion of the polarizing film 22 between the movable roller 20 and the end 31 a of the sheet 31 toward the movable roller 20.

[0056] The rear ends 37a of the outer peripheral surfaces 37 of the tension rollers 36 are located at the same position or adjacent positions in the front-rear direction relative to the rear surface 33 of the sheet 31. In this embodiment, furthermore, a measure is taken to regulate the positions of the first polarization section 23 and the second polarization section 24 in the front-rear direction.

[0057] In each main frame portion 16, the end 31a of the sheet 31 enters the main storage portion 17 through the inner end opening 18, as described above. Furthermore, in each main frame portion 16, a portion of the polarizing film 22 in the up-down direction is located rearward of the end 31a of the sheet 31. Each main frame portion 16 has a protrusion 15 at its inner end in the up-down direction. Each protrusion 15 is provided on the rear side of a portion of the polarizing film 22 that is located rearward of the end 31a within the main frame portion 16. Each protrusion 15 protrudes forward from the inner end of the rear frame-constituting portion 13 in the up-down direction. The front surface of each protrusion 15 is located between the two rear ends 21a in the front-rear direction, in a position that contacts or approaches the rear of the polarizing film 22 that is taut and has no slack or curl.

[0058] Each protrusion 15 may be provided as a part of the rear frame component 13, or may be provided as a separate member. It should be noted that an operating portion (not shown) for operating the movable roller 20 to rotate is provided on a part of the frame 9, for example, one of the main frame portions 16.

[0059] <Operation of this embodiment> In the light control device D, when one of the movable rollers 20 is rotated by operating the operation unit, the rotation is transmitted to the other of the movable rollers 20 via the polarizing film 22. This transmission causes the other of the movable rollers 20 to rotate in the same direction in synchronization with the one of the movable rollers 20. As both of the movable rollers 20 rotate, the first polarization unit 23 and the second polarization unit 24 move in opposite directions along the up-and-down direction.

[0060] When light is incident on the light control device D shown in Fig. 1 from the front, the light is transmitted through the transparent sheet 31. When the light is incident on the first polarization unit 23, the light becomes linearly polarized in a direction along the first polarization axis PA1 when passing through the first polarization region A1 shown in Figs. 3 and 6. Furthermore, the light incident on the first polarization unit 23 becomes linearly polarized in a direction along the second polarization axis PA2 when passing through the second polarization region A2.

[0061] 3, 4, and 6, the degree of light transmission through the first polarization unit 23 and the second polarization unit 24 is determined by which of the polarization regions A1, A2 in the second polarization unit 24 faces (overlaps) in the front-to-back direction with respect to the polarization regions A1, A2 in the first polarization unit 23. The combination of the first polarization axis PA1 and the second polarization axis PA2 facing in the front-to-back direction can be changed by moving the first polarization unit 23 and the second polarization unit 24 relative to each other in the vertical direction. This relative movement is achieved by rotating the pair of movable rollers 20 in response to operation of the operation unit, and moving the first polarization unit 23 and the second polarization unit 24 in opposite directions along the vertical direction.

[0062] As a result of the above movement, for example, when the first polarization region A1 in the first polarizing unit 23 and the first polarization region A1 in the second polarizing unit 24 face each other in the front-to-back direction, dimming is performed as follows. The direction in which the first polarization axis PA1 in the first polarization region A1 extends is parallel to the direction in which the first polarization axis PA1 in the latter first polarization region A1 extends. In this case, the second polarization region A2 in the first polarizing unit 23 and the second polarization region A2 in the second polarizing unit 24 face each other in the front-to-back direction. The direction in which the second polarization axis PA2 in the former second polarization region A2 extends is parallel to the direction in which the second polarization axis PA2 in the latter second polarization region A2 extends. Therefore, all of the light incident on the first polarizing unit 23 and transmitted through the first polarizing unit 23 is transmitted through the second polarizing unit 24.

[0063] In contrast, when the above movement causes the first polarization region A1 in the first polarizing unit 23 and the second polarization region A2 in the second polarizing unit 24 to face each other in the front-to-back direction, light control is performed as follows. The direction in which the first polarization axis PA1 in the first polarization region A1 extends is perpendicular to the direction in which the second polarization axis PA2 in the second polarization region A2 extends. In this case, the second polarization region A2 in the first polarizing unit 23 and the first polarization region A1 in the second polarizing unit 24 face each other in the front-to-back direction. The direction in which the second polarization axis PA2 in the second polarization region A2 extends is perpendicular to the direction in which the first polarization axis PA1 in the first polarization region A1 extends. Therefore, all light that enters the first polarizing unit 23 and then transmits through the first polarizing unit 23 is blocked (shielded) by the second polarizing unit 24.

[0064] In this way, as the pair of movable rollers 20 rotate, the first polarization section 23 and the second polarization section 24 move in opposite directions along the vertical direction, thereby adjusting the degree of light transmission in the first polarization section 23 and the second polarization section 24.

[0065] 7A and 7B show a portion of the first polarizing layer 23a and a portion of the second polarizing layer 24a extracted from the light control device D. These figures also show a state in which the first polarizing region A1 in the first polarizing layer 23a and the first polarizing region A1 in the second polarizing layer 24a face each other in the front-to-back direction, i.e., are at the same height. In this state, the second polarizing region A2 in the first polarizing layer 23a and the second polarizing region A2 in the second polarizing layer 24a face each other in the front-to-back direction. If a user U were to view the first polarizing layer 23a from the front, the first polarizing layer 23a and the second polarizing layer 24a would be visible through the first polarizing layer 23a and the second polarizing layer 24a. This is because light that has passed through the first polarizing layer 23a passes through the second polarizing layer 24a.

[0066] In contrast, as shown in Figures 7(A) and (B), when a user U views the first polarizing layer 23a in a direction inclined relative to the front-to-rear direction, for example, from diagonally above the front, a black stripe (line) extending in the left-to-right direction is visible at the boundary between the adjacent first polarizing region A1 and second polarizing region A2. As shown in Figure 7(A), when the distance between the first polarizing layer 23a and the second polarizing layer 24a in the front-to-rear direction is narrow, the width W of this stripe is narrow and the stripe is not noticeable. However, as shown in Figure 7(B), as the distance increases, the width W increases. As the width W increases, the stripe becomes more noticeable, and the display quality of the light control device D decreases.

[0067] In this regard, in this embodiment, as shown in FIG. 1, the second polarizing portion 24 of the polarizing film 22 is located between the rear ends 21a of the outer circumferential surfaces 21 of the pair of movable rollers 20. Here, the rear surface 33 of the sheet 31 and the rear end 21a of the outer peripheral surface 21 of the movable roller 20 are located at the same position or adjacent positions in the front-to-rear direction. As a result, the second polarization unit 24 is parallel or nearly parallel to the rear surface 33 of the sheet 31 at a position close to the rear surface 33.

[0068] In contrast, the first polarization unit 23 is located between the sheet 31 and the second polarization unit 24. The first polarization unit 23 is sandwiched between the sheet 31 and the second polarization unit 24 in the front-to-back direction. The position of the first polarization unit 23 in the front-to-back direction is restricted by the sheet 31 and the second polarization unit 24. The first polarization unit 23 is parallel or nearly parallel to the second polarization unit 24 and the sheet 31. As a result, the first polarization unit 23 and the second polarization unit 24 are maintained with a narrow gap between them in the front-to-back direction.

[0069] Meanwhile, each tension roller 36 presses the portion of the polarizing film 22 between the movable roller 20 and the end 31a of the sheet 31 toward the movable roller 20. This pressing brings the first polarization unit 23 closer to the second polarization unit 24. The portion of the polarizing film 22 between each movable roller 20 and each tension roller 36 is inclined in both the up-down direction and the front-to-back direction so that the outermost portions are positioned further forward in the up-down direction.

[0070] Furthermore, by pressing, each tension roller 36 applies tension to the polarizing film 22. This tension keeps the polarizing film 22 in a taut state. The first polarizing unit 23 and the second polarizing unit 24 are maintained in a state where the gap between them in the front-to-rear direction is narrow.

[0071] In particular, in this embodiment, the rear ends 37a of the outer peripheral surfaces 37 of the tension rollers 36 and the rear surface 33 of the sheet 31 are located at the same or adjacent positions in the front-to-rear direction. Therefore, the first polarization unit 23 is adjacent to the second polarization unit 24 and the sheet 31, between the sheet 31 and the second polarization unit 24, in a state that is more parallel or nearly parallel to the second polarization unit 24 and the sheet 31. The distance between the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction is maintained narrower with greater precision.

[0072] 1, when the first polarization unit 23 comes into contact with the rear surface 33 from behind, the sheet 31 restricts the forward movement of the first polarization unit 23 and the second polarization unit 24. Moreover, the sheet 31 exerts this restriction over the entire wide rear surface 33. As a result, it becomes even easier to maintain the narrow distance between the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction.

[0073] Furthermore, when the second polarization unit 24 comes into contact with the protrusions 15 provided on each main frame portion 16, the protrusions 15 restrict the first polarization unit 23 and the second polarization unit 24 from moving rearward. The first polarization unit 23 and the second polarization unit 24 are sandwiched from both sides in the front-to-rear direction by the end portion 31a of the sheet 31 and the protrusions 15, and are restricted from moving in the same direction. The provision of the protrusions 15 reduces the dimension of the inner end open portion 18 in the front-to-rear direction. This further improves the accuracy of the spacing between the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction.

[0074] Incidentally, the distance between the first polarization unit 23 and the second polarization unit 24 outside the frame 9 affects the front-to-rear dimension of the light control device D, particularly the front-to-rear dimension outside the frame 9. The smaller the distance outside the frame 9, the smaller the effect.

[0075] Here, in this embodiment, the portions of the first polarization unit 23 and the second polarization unit 24 outside the frame 9 refer to the portions that are not sandwiched or hidden by the front frame component 11 and the rear frame component 13. In other words, the portions outside the frame 9 are the portions that the user U can see from the front or rear of the light control device D.

[0076] In this respect, in this embodiment, the part indicated by "outside the frame 9" is different from the part indicated by "outside the window frame" used when explaining the positional relationship of each part of a general window. Incidentally, when explaining the positional relationship of each part of a general window, "inside the window frame" refers to the area of ​​the window glass surrounded by the window frame, and "inside the window frame" refers to the area outside the window frame.

[0077] In this embodiment, the first polarizing unit 23 and the second polarizing unit 24 are spaced apart in the front-to-rear direction outside the frame 9, thereby narrowing the gap between the first polarizing layer 23a and the second polarizing layer 24a and maintaining that gap. The narrow gap between the first polarizing layer 23a and the second polarizing layer 24a is, for example, 1 mm or less, and more preferably 0.5 mm or less. Therefore, the width W of the streaks is narrowed as shown in FIG. 7(A), making the streaks less noticeable.

[0078] Furthermore, by setting the distance between the first polarizing layer 23a and the second polarizing layer 24a to 1 mm or less outside the frame 9 as described above, the influence of the overall front-to-rear dimensions of the first polarizing section 23 and the second polarizing section 24 on the front-to-rear dimensions of the dimming device D outside the frame 9 is reduced.

[0079] 1, in order to maintain a narrow gap between the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction, it is not necessary to use a tension roller that presses the second polarization unit 24 forward, unlike Patent Document 1. As the number of tension rollers 36 is reduced, the overall dimension of the tension rollers 36 in the front-to-rear direction becomes smaller than in Patent Document 1, in which a pair of tension rollers are arranged side by side in the front-to-rear direction.

[0080] Additionally, as the number of tension rollers 36 is reduced, the overall weight of the tension rollers 36 used is reduced. Here, if the tension roller 36 is not used, or if the tension roller 36 is used but the rear end 37a of the tension roller 36 is located forward of the rear surface 33 of the sheet 31, the following concern arises.

[0081] In either case, a portion of the polarizing film 22 is inclined so that the outermost portion is positioned further forward in the vertical direction relative to the rear surface 33 of the sheet 31. When the tension roller 36 is not provided, the portion of the polarizing film 22 between the movable roller 20 and the sheet 31 is inclined. When the tension roller 36 is used and the rear end 37a of its outer circumferential surface 37 is positioned further forward than the rear surface 33 of the sheet 31, the portion of the polarizing film 22 between the tension roller 36 and the sheet 31 is inclined.

[0082] In either case, the inclined portion of polarizing film 22 moves while being pressed against corner 35 between outer end surface 34 of sheet 31 in the vertical direction and rear surface 33. Friction between corner 35 and polarizing film 22 may cause wear and reduce durability.

[0083] In this regard, the present embodiment provides a tension roller 36. Furthermore, the rear end 37a of the outer peripheral surface 37 of the tension roller 36 and the rear surface 33 of the sheet 31 are located at the same position or adjacent positions in the front-to-rear direction. Therefore, the portion of the polarizing film 22 between the tension roller 36 and the sheet 31 is parallel or nearly parallel to the rear surface 33 of the sheet 31. This portion of the polarizing film 22 is unlikely to move while being pressed by the corners 35 of the sheet 31.

[0084] Furthermore, in this embodiment, the entire movable roller 20, the end 31a of the sheet 31, and the entire tension roller 36 are covered and hidden by the main frame portion 16, and therefore cannot be seen from the outside of the light control device D. This improves the appearance of the light control device D compared to when the above-mentioned parts of the light control device D are visible.

[0085] Furthermore, the main frame 16 protects the above-mentioned components from external impacts, heat, humidity, and the like. Furthermore, the sheet 31 has higher rigidity than the polarizing film 22. Therefore, when an impact is applied to the light control device D from the front, the impact is absorbed by the sheet 31. The sheet 31 prevents the impact from acting on the polarizing film 22.

[0086] <Effects of this embodiment> (1) In this embodiment, as shown in FIG. 1 , a sheet 31 having higher rigidity than the polarizing film 22 is disposed between a pair of movable rollers 20 between which the polarizing film 22 is stretched and in front of the first polarizing unit 23. The first polarizing unit 23 is adjacent to the second polarizing unit 24 and the sheet 31. A tension roller 36 is disposed between each movable roller 20 and an end 31 a of the sheet 31, and applies tension to the polarizing film 22 by pressing the polarizing film 22 toward the side that brings the first polarizing unit 23 closer to the second polarizing unit 24.

[0087] Therefore, unlike Patent Document 1, although a tension roller that presses the second polarization unit 24 forward is not used, the distance between the first polarization unit 23 and the second polarization unit 24 can be maintained at a small value of 1 mm or less. By reducing the number of tension rollers 36, the light control device D can be made thinner in the front-rear direction and lighter in weight.

[0088] As a result, when the light control device D is installed near a window in a room, the amount by which the light control device D protrudes from the window toward the room side can be reduced. Furthermore, when the user U views the dimming device D in a direction inclined relative to the front-to-back direction, for example, from diagonally above the front, the visibility of black streaks can be reduced, thereby preventing a decrease in the display quality of the dimming device D due to the visibility of black streaks.

[0089] (2) Furthermore, the polarizing film 22 is prone to wrinkling due to environmental changes, such as shrinkage due to drying and expansion due to water absorption. However, in this embodiment, the tension roller 36 applies tension to the polarizing film 22 in the outward direction in the vertical direction. Therefore, even if the environment changes, the polarizing film 22 is less likely to wrinkle. This makes it possible to suppress deterioration in display quality due to wrinkles.

[0090] (3) In this embodiment, the rear surface 33 of the sheet 31 is located at the same position as or adjacent to the rear ends 21a of the outer circumferential surfaces 21 of the pair of movable rollers 20 in the front-rear direction.

[0091] Therefore, the second polarization unit 24, which is located between the rear ends 21a of the pair of movable rollers 20, can be made parallel or nearly parallel to the rear surface 33 of the sheet 31 at a location close to the rear surface 33. Furthermore, the portion of the first polarization unit 23 that is located between the sheet 31 and the second polarization unit 24 can be made parallel or nearly parallel to the second polarization unit 24 and the sheet 31. As a result, the distance between the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction can be maintained at an even smaller value.

[0092] (4) In this embodiment, each tension roller 36 applies tension to the polarizing film 22 by pressing a portion of the polarizing film 22 between each movable roller 20 and the end 31a of the sheet 31 toward the movable roller 20. The rear ends 37a of the outer surfaces 37 of the tension rollers 36 are located at the same or adjacent positions on the rear surface 33 of the sheet 31 in the front-to-rear direction.

[0093] Therefore, the portions of the polarizing film 22 between the tension rollers 36 and the edge 31a of the sheet 31 can be made parallel or nearly parallel to the rear surface 33 of the sheet 31. This can prevent the above-mentioned portions of the polarizing film 22 from moving while being pressed against the corners 35 of the sheet 31. As a result, it is possible to prevent a decrease in durability of the polarizing film 22 due to friction that occurs when the polarizing film 22 moves while being pressed.

[0094] (5) In this embodiment, each main frame portion 16 has a protrusion 15. Each protrusion 15 is provided on the rear side of a portion of the polarizing film 22 that is located behind the end 31a of the sheet 31 within the main frame portion 16. Each protrusion 15 protrudes forward from the inner end of the rear frame-constituting portion 13 in the up-down direction.

[0095] Therefore, by sandwiching the first polarization unit 23 and the second polarization unit 24 from both sides in the front-to-rear direction between the end 31a of the sheet 31 and both protrusions 15, it is possible to restrict the movement of the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction within each main frame portion 16. As a result, it is possible to further improve the accuracy of the spacing between the first polarization unit 23 and the second polarization unit 24 in the front-to-rear direction.

[0096] The weight increase due to the addition of both protrusions 15 is slight. This increase is smaller than the weight increase that would occur if a tension roller that presses the polarizing film 22 from behind were added. Furthermore, the addition of both protrusions 15 has a minimal effect on the dimensions of the light control device D in the front-to-rear direction. This effect is smaller than the effect that a tension roller that presses the polarizing film 22 from behind would have on the dimensions.

[0097] <Example of change> This embodiment can be modified as follows: This embodiment and the following modifications can be combined and implemented within the scope of technical compatibility.

[0098] The frame 9 may have a main frame portion 16 and a connecting frame portion 19 extending in directions different from those in the above embodiment. For example, the frame 9 may have a main frame portion 16 extending in the up-down direction and a connecting frame portion 19 extending in the left-right direction, which is the opposite of the above embodiment. In this case, the pair of movable rollers 20 are arranged parallel to and spaced apart from each other in the left-right direction. The arrangement direction of the pair of movable rollers 20 coincides with the left-right direction. The first polarization unit 23 and the second polarization unit 24 move in opposite directions along the left-right direction as the movable roller 20 rotates.

[0099] Furthermore, each of the main frame portion 16 and the connecting frame portion 19 of the frame 9 may extend in a direction inclined with respect to the vertical and horizontal directions. The protrusions 15 on one or both of the main frame portions 16 may be omitted.

[0100] The protrusion 15 may be provided in a different position in the main frame 16 from that in the above embodiment, provided that the protrusion 15 is provided behind a portion of the polarizing film 22 that is located behind the end 31a of the sheet 31 within the main frame 16. For example, the protrusion 15 may be provided in a position that is outward in the up-down direction from that in the above embodiment.

[0101] The second polarization axis PA2 in each second polarizing region A2 may be arranged in a different manner (polarization axis pattern) from that in the above embodiment, provided that the second polarization axis PA2 extends in a direction perpendicular to the first polarization axis PA1 in each first polarizing region A1. Examples of such arrangements are shown in Figures 8 and 9.

[0102] 8, the first polarization axis PA1 is tilted at 45° with respect to the left-right direction, and the second polarization axis PA2 is tilted at 45° with respect to the left-right direction in the opposite direction to the first polarization axis PA1.

[0103] In the polarization axis pattern shown in Fig. 9, the first polarization region A1 and the second polarization region A2 are each divided into a plurality of small sections in their length direction (the left-right direction in Fig. 9). The first polarization axis PA1 and the second polarization axis PA2 are arranged so that the directions of the polarization axes of adjacent small sections are perpendicular to each other. In this case, the first polarization axis PA1 and the second polarization axis PA2 are arranged so that the small section of the first polarization region A1 and the adjacent small section of the second polarization region A2 extend in different directions from each other.

[0104] The second polarization axis PA2 may extend in a direction that intersects (is tilted) obliquely with the first polarization axis PA1, instead of in a direction that is perpendicular to the first polarization axis PA1. Contrary to the above embodiment, the polarizing regions A1 and A2 may be formed on the outer peripheral surface of the loop-shaped film substrate 27. In this case, in the first polarizing section 23, the polarizing regions A1 and A2 are formed on the front surface of the film substrate 27. In the second polarizing section 24, the polarizing regions A1 and A2 are formed on the rear surface of the film substrate 27.

[0105] The tension roller 36 may be disposed only between the movable roller 20 on one side and the edge 31 a on one side of the sheet 31 . A compression spring (compression spring) such as a compression coil spring that presses the tension roller 36 toward the movable roller 20 may be used as the elastic body that biases the tension roller 36 toward the movable roller 20 (outward in the arrangement direction).

[0106] Similar to the sheet 31, a transparent sheet may be additionally disposed between the pair of movable rollers 20 and behind the second polarization unit 24. This additional sheet may be disposed between the pair of main frame units 16. Furthermore, the vertical ends of the additional sheet may be inserted into the main storage unit 17 of the main frame unit 16, as in the above embodiment.

[0107] The diameter of the movable roller 20 and the diameter of the tension roller 36 may be the same or different. The axis L1 of the movable roller 20 and the axis L2 of the tension roller 36 may be located at the same position in the front-rear direction, or may be located at different positions. [Explanation of symbols]

[0108] 9...Frame 15...Protrusion 16...Main frame section 20... Movable roller 21,37...Outer surface 21a,37a...rear end 22...Polarizing film 23...First polarization unit (polarization unit) 24...Second polarizing unit (polarizing unit) 31...seat 31a...end 33…Rear side 36...Tension roller D…Dimmer device PA1...First polarization axis (polarization axis) PA2: Second polarization axis (polarization axis) U…User

Claims

1. If the direction facing the user is defined as the front-rear direction, and the side closer to the user in the front-rear direction is defined as the front side, and the side farther from the user is defined as the rear side, a pair of movable rollers arranged parallel to and spaced apart from each other in a direction perpendicular to the front-rear direction; and a loop-shaped polarizing film stretched across the pair of movable rollers, the polarizing film includes a first polarizing section and a second polarizing section, each having a polarization axis and facing each other in the front-rear direction, between the pair of movable rollers; the first polarization unit is located in front of the second polarization unit, a light control device in which the first polarization unit and the second polarization unit move in opposite directions to each other along an arrangement direction of the pair of movable rollers in accordance with rotation of the pair of movable rollers, thereby adjusting a degree of light transmission in the first polarization unit and the second polarization unit, a transparent sheet having a higher rigidity than the polarizing film is disposed between the pair of movable rollers and in front of the first polarization unit; the first polarizing unit has a portion adjacent to the second polarizing unit and the sheet, A dimming device in which a tension roller is disposed between at least one of the movable rollers and the sheet and in front of the first polarization unit, the tension roller applying tension to the polarization film by pressing the polarization film toward the side that brings the first polarization unit closer to the second polarization unit.

2. The light control device according to claim 1 , wherein the rear surface of the sheet is located at the same position or adjacent position in the front-rear direction with respect to rear ends of the outer circumferential surfaces of the pair of movable rollers.

3. the tension roller applies the tension to the polarizing film by pressing a portion of the polarizing film between the movable roller and the sheet toward the movable roller, The light control device according to claim 2 , wherein a rear end of the outer peripheral surface of the tension roller is located at the same position or an adjacent position in the front-rear direction with respect to the rear surface of the sheet.

4. A light control device further comprising a frame having a pair of main frame portions, The movable roller is rotatably supported within each main frame portion, and an end portion of the sheet in the arrangement direction is inserted within each main frame portion, Furthermore, a portion of the polarizing film is located behind the end of the sheet within each main frame portion, The light control device according to any one of claims 1 to 3, wherein at least one of the main frame portions is provided on the rear side of a portion of the polarizing film that is located behind the end of the sheet within the main frame portion, and has a protrusion that protrudes forward.

5. If the direction facing the user is the front-to-rear direction, a polarizing film having a pair of polarizing portions each having a polarization axis and facing each other in the front-rear direction is used, A light control device in which the pair of polarizing units moves in opposite directions to each other along a direction perpendicular to the front-rear direction, thereby adjusting the degree of light transmission through the pair of polarizing units, a frame is provided on the periphery of the pair of polarizing units, A light control device in which the distance between the pair of polarizing units is 1 mm or less outside the frame.

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