Polarizing element unit, polarized light irradiation unit, polarized light irradiation device, and polarized light irradiation method

Abstract

The invention provides a polarization element unit, a polarized light irradiation unit, a polarized light irradiation device and a polarized light irradiation method, which can irradiate polarized light with little deviation of a polarization axis in a wide range. A polarizing element unit according to one embodiment of the present invention is a polarizing element unit that polarizes incident light, and is provided with a frame and a plurality of wire grid polarizing elements. The frame is fixed relative to the light source. The plurality of wire grid polarization elements are arranged along the long side direction of the light source, each wire grid polarization element is supported by the frame in a manner of being capable of rotating around the optical axis direction of the light incident from the light source, and compared with other wire grid polarization elements, at least one wire grid polarization element is provided with a plurality of wire grid polarization elements which can rotate around the optical axis direction of the light incident from the light source. And the width in the long side direction is small, or the rotatable range around the optical axis direction is large.

Description

Technical Field

[0001] The present invention relates to a polarization element unit for generating polarized light, a polarized light irradiation unit, a polarized light irradiation device, and a polarized light irradiation method. Background Art

[0002] There is a technology called photo-alignment, which uses polarized light of a predetermined wavelength to irradiate an irradiation target, such as an alignment film of a liquid crystal panel, to achieve alignment. For photo-alignment of long, strip-shaped irradiation targets, a polarized light irradiation device is known that combines a rod-shaped lamp with a wire-grid polarizer (for example, Patent Document 1). In this polarized light irradiation device, light emitted from the rod-shaped lamp and polarized by the wire-grid polarizer is irradiated onto the irradiation target, achieving photo-alignment.

[0003] A wire-grid polarizer is made by placing metal wires, such as aluminum, in parallel on a surface of quartz glass. When a wire-grid polarizer is inserted into an electromagnetic wave, the polarization component parallel to the longitudinal direction of the wire grid is reflected, while the polarization component perpendicular to that direction passes through. The orientation of the polarization axis in the irradiated object depends on the direction of the polarization axis of the incident polarized light, so the uniformity of the polarization axis is crucial.

[0004] Because the rod-shaped lamp is a diffuse light source, when the longitudinal direction of the rod-shaped lamp is oriented horizontally, light enters the wire-grid polarizer near the center of the lamp from directly above and from both the left and right directions. On the other hand, light from the left or right does not enter the wire-grid polarizer at the ends of the lamp. Consequently, the polarization axis of the polarized light emitted from the wire-grid polarizer at the ends of the lamp is significantly shifted (deviation), resulting in polarized light with a shifted (deviation) polarization axis being irradiated at the ends of the polarized light area. In particular, when the longitudinal direction of the wire grid is oriented at 45° relative to the longitudinal direction of the rod-shaped lamp, the area irradiated with polarized light with a shifted (deviation) polarization axis becomes larger.

[0005] Therefore, a polarized light irradiation device has been developed in which a polarized light irradiation unit including a rod-shaped lamp and a wire-grid polarizing element can be rotated relative to the irradiation object (for example, Patent Document 2). In this configuration, the longitudinal direction of the wire grid can be changed relative to the irradiation object while the longitudinal direction of the rod-shaped lamp and the longitudinal direction of the wire grid are aligned, thereby preventing areas from being irradiated with polarized light having a shifted polarization axis.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Laid-Open No. 2006-133498

[0009] Patent Document 2: Japanese Patent Application Laid-Open No. 2006-126464 Summary of the Invention

[0010] Problems to be solved by the invention

[0011] However, when rotating the polarized light irradiation unit as described in Patent Document 2, space is required for the rotation, limiting the possible installation locations. Furthermore, when the polarized light irradiation unit is rotated, the distance and angle between the unit and the irradiated object change, sometimes affecting the irradiation conditions of the polarized light. Therefore, a polarized light irradiation unit is sought that can irradiate polarized light with minimal polarization axis deviation over a wide area without being restricted by the installation location.

[0012] In view of the above circumstances, an object of the present invention is to provide a polarization element unit, a polarized light irradiation unit, a polarized light irradiation device, and a polarized light irradiation method capable of irradiating a wide area with polarized light having a small shift in the polarization axis.

[0013] Technical solutions to problems

[0014] To achieve the above-mentioned object, a polarization element unit according to one embodiment of the present invention is a polarization element unit that polarizes incident light and includes a frame and a plurality of wire grid polarization elements.

[0015] The frame is fixed relative to the light source.

[0016] The plurality of wire grid polarization elements are arranged along the long side direction of the light source, and the wire grid polarization elements are supported on the frame in a manner such that they can rotate around the optical axis direction of the light incident from the light source. At least one of the wire grid polarization elements has a smaller width in the long side direction or a larger rotation range around the optical axis direction than the other wire grid polarization elements.

[0017] According to this configuration, by rotating each wire grid polarization element about the optical axis of light incident from the light source, it is possible to eliminate shift (deviation) in the polarization axis of the illumination plane of light that has passed through the polarization element unit. In this case, by having at least one wire grid polarization element with a smaller width or a larger rotational range than the other wire grid polarization elements, it is easier to eliminate shift in the polarization axis according to the position of the wire grid polarization element.

[0018] At least one wire grid polarization element may have a smaller width in the longitudinal direction and a larger rotatable range around the optical axis than the other wire grid polarization elements.

[0019] Among the plurality of wire grid polarization elements, the width of the wire grid polarization elements located at the ends in the longitudinal direction may be smaller than the width of the wire grid polarization element located at the center in the longitudinal direction.

[0020] Among the plurality of wire grid polarization elements, the rotatable range of the wire grid polarization element located at the end in the longitudinal direction may be larger than the rotatable range of the wire grid polarization element located at the center in the longitudinal direction.

[0021] Among the plurality of wire grid polarization elements, the width in the longitudinal direction may be smaller as the wire grid polarization element is closer to an end in the longitudinal direction.

[0022] Among the plurality of wire grid polarization elements, the rotatable range may be larger for a wire grid polarization element closer to an end in the longitudinal direction.

[0023] The extending direction of the wires of each of the wire grid polarization elements may be non-parallel to the longitudinal direction and non-orthogonal to the longitudinal direction.

[0024] The extending direction of the wires of each of the wire grid polarization elements may form an angle of 45° with respect to the longitudinal direction.

[0025] To achieve the above-mentioned object, a polarization element unit according to one embodiment of the present invention is a polarized light irradiation unit for emitting polarized light, and includes a light source, a frame, and a plurality of wire grid polarization elements.

[0026] The frame is fixed relative to the light source.

[0027] The wire grid polarization elements are multiple wire grid polarization elements arranged along the long side direction of the light source. The wire grid polarization elements are supported on the frame in a manner that allows them to rotate around the optical axis direction of the light incident from the light source. At least one of the wire grid polarization elements has a smaller width in the long side direction or a larger rotation range around the optical axis direction than the other wire grid polarization elements.

[0028] In order to achieve the above-mentioned object, a polarized light irradiation device according to one embodiment of the present invention includes a polarized light irradiation unit and a transport mechanism.

[0029] The polarized light irradiation unit includes: a light source; a frame fixed relative to the light source; and a plurality of wire grid polarization elements arranged along the long side direction of the light source, and the wire grid polarization elements are supported on the frame in a manner such that they can rotate around the optical axis direction of the light incident from the light source, and at least one of the wire grid polarization elements has a smaller width in the long side direction or a larger range of rotation around the optical axis direction than the other wire grid polarization elements.

[0030] The transport mechanism transports the irradiation object.

[0031] In order to achieve the above-mentioned object, a polarized light irradiation method according to one embodiment of the present invention is a polarized light irradiation method for irradiating a polarized light onto an irradiation object, wherein:

[0032] Light from a light source is caused to be incident on a polarization element unit, which includes: a frame fixed relative to the light source; and a plurality of wire grid polarization elements arranged along the longitudinal direction of the light source, wherein the wire grid polarization elements are supported on the frame in a manner such that they can rotate around the optical axis direction of the light incident from the light source, and at least one of the wire grid polarization elements has a smaller width in the longitudinal direction or a larger range of rotation around the optical axis direction than the other wire grid polarization elements.

[0033] Effects of the Invention

[0034] According to the present invention, it is possible to provide a polarization element unit, a polarized light irradiation unit, a polarized light irradiation apparatus, and a polarized light irradiation method capable of irradiating a wide area with polarized light having a small shift in the polarization axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a schematic diagram of a polarized light irradiation device according to an embodiment of the present invention.

[0036] Figure 2 It is a schematic diagram of a polarization element unit included in the polarized light irradiation device.

[0037] Figure 3 It is a schematic diagram of a polarization element unit included in the polarized light irradiation device.

[0038] Figure 4 It is a schematic diagram of a polarization element unit included in the polarized light irradiation device.

[0039] Figure 5 It is a schematic diagram of a support mechanism for the polarizing element in the polarizing element unit.

[0040] Figure 6 It is a schematic diagram of a support mechanism for the polarizing element in the polarizing element unit.

[0041] Figure 7 It is a schematic diagram of a support mechanism for the polarizing element in the polarizing element unit.

[0042] Figure 8 This is a graph showing the deviation of the polarization axis in the light irradiation plane of the polarized light irradiation device.

[0043] Figure 9 This is a graph showing the deviation of the polarization axis in the light irradiation plane of the polarized light irradiation device.

[0044] Figure 10This is a graph showing the deviation of the polarization axis in the light irradiation plane of the polarized light irradiation device.

[0045] Figure 11 Schematic diagram showing light incident on the polarization element unit.

[0046] Figure 12 This is a schematic diagram of a structure for suppressing the shift of the polarization axis in the polarization element unit.

[0047] Figure 13 This is a schematic diagram of a structure for suppressing the shift of the polarization axis in the polarization element unit.

[0048] Figure 14 Schematic diagram showing the rotation of the polarizer in the polarizer unit.

[0049] Figure 15 It is a schematic diagram showing the width of the polarizer in the polarizer unit.

[0050] Figure 16 It is a schematic diagram of a polarization element unit having another structure according to this embodiment. DETAILED DESCRIPTION

[0051] A light source device according to an embodiment of the present invention will be described.

[0052] [Structure of Polarized Light Irradiation Device]

[0053] Figure 1 1 is a schematic diagram showing the structure of the polarized light irradiation device 100 according to this embodiment. As shown in the figure, the polarized light irradiation device 100 includes a transport mechanism 110 and a polarized light irradiation unit 120.

[0054] The transport mechanism 110 is a mechanism for transporting the irradiation object 150. The irradiation object 150 is an object to be irradiated with polarized light, such as an alignment film of a liquid crystal display. Figure 1 The irradiation target 150 is shown in a long strip shape, and is wound around rollers 111 and 112 of the conveying mechanism 110 and conveyed by their rotation. It should be noted that the irradiation target 150 is not limited to a long strip shape, and the conveying mechanism 110 is not limited to the structure shown here.

[0055] The polarized light irradiation unit 120 is a unit for irradiating the irradiation object 150 with polarized light. Figure 1 As shown, the polarized light irradiation unit 120 includes a light source 121 , a condenser lens 122 , and a polarizing element unit 123 .

[0056] Light source 121 has a shape extending in one direction and emits light. Hereinafter, the longitudinal direction of light source 121 is referred to as the X direction. Furthermore, when the direction in which the irradiated object 150 is transported is referred to as the transport direction, the transport direction is a direction perpendicular to the X direction, and this direction is referred to as the Y direction. Furthermore, a direction perpendicular to the X and Y directions is referred to as the Z direction. The Z direction coincides with the optical axis of the light incident from light source 121 onto polarized light irradiation unit 120.

[0057] The light source 121 is a rod-shaped lamp with its longitudinal side in the X direction, and can be a high-pressure mercury lamp, a metal halide lamp, or the like. Alternatively, the light source 121 may be a light-emitting element such as an LED (Light Emitting Diode) or an LD (Laser Diode). In this case, the light source 121 may be a plurality of light-emitting elements arranged linearly along the X direction.

[0058] The condenser lens 122 is disposed on the side of the light source 121 opposite to the irradiation object 150, and reflects the light incident from the light source 121 toward the irradiation object 150. Figure 1 As shown, the condenser mirror 122 can be formed into a curved surface having a curvature in the Y direction and extending in the X direction. Furthermore, the condenser mirror 122 only needs to reflect the light incident from the light source 121 toward the irradiation object 150. Furthermore, if the light source 121 is a light-emitting element, the condenser mirror 122 may not be required.

[0059] The polarization element unit 123 polarizes the light incident from the light source 121 and the condenser lens 122 to generate polarized light. Figure 2 13 is a schematic diagram of the polarization element unit 123. As shown in the figure, the polarization element unit 123 includes a frame 131 and a plurality of polarization elements 132.

[0060] The frame 131 is fixed to the light source 121 directly or via another member and supports the plurality of polarizers 132. The frame 131 can be formed into a frame-like shape having an opening 131a with its longitudinal direction in the X direction and its transverse direction in the Y direction. The frame 131 can also have other shapes and can be composed of multiple members.

[0061] The polarization element 132 includes a wire grid and is a polarization element that polarizes incident light, and is also called a wire grid polarization element. Figure 2 As shown in FIG. 1 , the polarizing element 132 includes a substrate 133 and a wire grid 134. The substrate 133 is made of quartz glass or the like and has a rectangular flat plate shape. Figure 2As shown, the wire grid 134 is a grid formed by a plurality of parallel wires 135. Each wire 135 is a linear conductor and is formed on a substrate 133. The wires 135 can be made of, for example, metals such as chromium or aluminum, metal oxides such as titanium oxide, zirconium oxide, hafnium oxide, or yttrium oxide, or metal nitrides such as titanium nitride. The pitch P of the wires 135 is preferably less than the wavelength of the incident light, preferably less than 1 / 3. Figure 2 As shown, a plurality of polarizing elements 132 are supported by a frame 131 and arranged along the longitudinal direction (X direction) of the light source 121 to form a polarizing element unit 123 .

[0062] The long side direction of line 135 is not limited to Figure 2 The X direction shown is a direction parallel to the longitudinal direction of the light source 121 . Figure 3 and Figure 4 Schematic diagram showing other structures of the polarization element 132. Figure 3 As shown, each polarizing element 132 may be a polarizing element in which the long side direction of the line 135 is in a direction (Y direction) perpendicular to the long side direction (X direction) of the light source 121. Figure 4 As shown, each polarizing element 132 may be a polarizing element in which the longitudinal direction of the line 135 is non-parallel to and non-orthogonal to the longitudinal direction (X direction) of the light source 121, specifically, in a direction (direction D1 in the figure) that forms an angle of 45° with the longitudinal direction (X direction) of the light source 121. The angle formed by the longitudinal direction of the line 135 and the longitudinal direction (X direction) of the light source 121 is not limited to 45° and can be set to any angle.

[0063] It should be noted that the polarizing element 132 is made by using a glass wafer as a substrate and utilizing photolithography or etching technology. However, there is a limit to the size of the substrate that can be processed by processing equipment such as evaporation equipment, photolithography equipment, and etching equipment. There is also a limit to the size of the polarizing element 132 cut out from the substrate. Therefore, when using a light source that is long in one direction, such as the light source 121, Figures 2 to 4 As shown, a plurality of polarizing elements 132 are arranged in a frame 131 , so that a polarizing element that is long in one direction can be formed.

[0064] The number of polarizers 132 included in the polarizer unit 123 is not particularly limited and can be set to a number corresponding to the length (X direction) of the light source 121 and the size of each polarizer 132. Specifically, it is preferred that the total length (X direction) of the plurality of polarizers 132 is approximately the same as the length (X direction) of the light source 121. For example, if the length (X direction) of the light source 121 is 1 m and the polarizers 132 are square with a side of 100 mm, the number of polarizers 132 is preferably 10.

[0065] The polarization element unit 123 also has a structure for suppressing the shift (deviation) of the polarization axis. The details will be described later.

[0066] [Regarding the Support Structure of the Polarizing Element]

[0067] As described above, the plurality of polarizing elements 132 are supported by the frame 131. Here, each polarizing element 132 is supported by the frame 131 so as to be rotatable about the optical axis direction (Z direction) of the light incident from the light source 121. Figure 5 1 is a top view showing a support structure of a polarizing element 132 to a frame 131. Figure 6 It is its side view. Figure 7 Schematic diagram showing the rotation of the polarizing element 132 based on this support structure.

[0068] like Figure 5 and Figure 6 As shown, a threaded hole 131b is provided in the frame 131, and screws 141A to C are inserted into the threaded hole 131b. The polarizing element 132 is supported on the frame 131 by being clamped by the screws 141A to C. Specifically, when one side surface (XZ plane) of the polarizing element 132 is set as the side surface 136 and the side surface (XZ plane) on the opposite side is set as the side surface 137, the screw 141A abuts against the middle of the side surface 136, the screw 141B abuts against the left side of the side surface 137 relative to the center, and the screw 141C abuts against the right side of the side surface 137 relative to the center. By pushing and pulling the screws 141B and 141C in this state, as shown Figure 7 As shown, the polarizing element 132 rotates with the screw 141A as a fulcrum, that is, rotates around the optical axis direction (Z direction).

[0069] By enabling the polarizer 132 to rotate about the optical axis (Z direction) of the light incident from the light source 121, the longitudinal direction of the line 135 can be finely adjusted. While the longitudinal direction of the line 135 may be subject to errors during manufacturing, rotating the polarizer 132 relative to the frame can eliminate these errors. The rotatable range of the polarizer 132 required to eliminate these errors is approximately ±0.5°.

[0070] The multiple polarizers 132 are supported on the frame 131 so that their ends overlap and they alternately form the upper and lower layers. This ensures that even if the polarizers 132 are rotated, no gaps are created between adjacent polarizers 132. This is because if gaps are created between adjacent polarizers 132, unpolarized light will leak through these gaps. It should be noted that, instead of arranging the polarizers 132 in two layers, the polarizers 132 can be arranged separately, with the gaps between the polarizers 132 covered by a light-shielding member.

[0071] The support structure of the polarizing element 132 with respect to the frame 131 is not limited to the above structure. Each polarizing element 132 may be supported by the frame 131 so as to be rotatable about the optical axis direction (Z direction) of the light incident from the light source 121 .

[0072] [Operation of the Polarized Light Irradiation Device]

[0073] The operation of the polarized light irradiation device 100 will be described. Figure 2 As shown, the long side direction of the line 135 of the polarizing element 132 is parallel to the long side direction of the light source 121 (X direction). When the light source 121 is turned on, the light emitted from the light source 121 enters the polarizing element unit 123 directly or reflected by the condenser 122. When the polarizing element 132 is present in the path of the light, the long side direction (X direction) of the line 135 in the light is parallel to the long side direction (X direction). Figure 2 Most of the polarization components parallel to the X direction are reflected by the wire grid 134, and the polarization components parallel to the X direction are reflected by the wire grid 134. Figure 2 The polarization component perpendicular to the long side direction (in the X direction) of the line 135 is transmitted through the wire grid 134. Figure 1 The direction perpendicular to the X direction ( Figure 1 The region 151 is polarized light with the Y direction (in the center) as the polarization axis direction.

[0074] In addition, if Figure 3 As shown, the polarizing element 132 can also be set so that the long side direction of the line 135 is perpendicular to the long side direction of the light source 121 (Y direction). In this case, the light incident on the polarizing element 132 is perpendicular to the long side direction of the line 135 ( Figure 3 Most of the polarization components parallel to the Y direction (in the figure) are reflected by the wire grid 134, and the polarization components parallel to the Y direction (in the figure) are reflected by the wire grid 134. Figure 3 The polarization component perpendicular to the long side direction (Y direction) of the line 135 is transmitted through the wire grid 134. Figure 1 The direction perpendicular to the Y direction ( Figure 1 The region 152 is a polarized light region with the polarization axis direction (X direction in the center) as the polarization axis direction.

[0075] Moreover, if Figure 4 As shown, the polarizing element 132 can also be set so that the long side direction of the line 135 is in the direction D1 that is 45 degrees with respect to the long side direction of the light source 121. In this case, the light incident on the polarizing element 132 is in the direction of the long side direction of the line 135 ( Figure 4 Most of the polarization components parallel to the direction D1 are reflected by the wire grid 134, and the polarization components parallel to the direction D2 are reflected by the wire grid 134. Figure 4The polarization component perpendicular to the direction D1 in the middle is transmitted through the wire grid 134. As a result, the irradiated object 150 is formed with the long side direction ( Figure 1 The direction perpendicular to the direction D1) ( Figure 1 The region 153 is a region where the polarized light has the direction D2 as the polarization axis direction.

[0076] When the irradiated object 150 is an alignment film used in a liquid crystal panel, etc., the alignment direction of the alignment film depends on the polarization axis direction of the polarized light irradiating the alignment film. The alignment direction generated in the alignment film varies depending on the purpose or type of the alignment film, the type of liquid crystal panel, the design rules of the liquid crystal panel manufacturer, etc., as shown in the above-mentioned regions 151 to 153 (see Figure 1 Therefore, various orientation directions are achieved by preparing in advance a polarizing element 132 in which the long side direction of the line 135 is 90° or 45° relative to the side, and attaching the polarizing element 132 corresponding to the purpose to the frame 131.

[0077] [About the deviation of the polarization axis]

[0078] When the polarized light irradiation device 100 irradiates the irradiation object 150 with polarized light, the polarization axis may shift. Figures 8 to 10 Graph showing deviation of the polarization axis in the light irradiation plane of the polarized light irradiation device 100 . Figure 8 When the longitudinal direction of the line 135 is parallel to the longitudinal direction of the light source 121 (X direction) (refer to Figure 2 )’s polarization axis deviation, Figure 9 When the longitudinal direction of the line 135 is perpendicular to the longitudinal direction of the light source 121 (Y direction) (refer to Figure 3 )’s polarization axis deviation, Figure 10 When the longitudinal direction of the line 135 is a direction (direction D1) that forms an angle of 45° with the longitudinal direction of the light source 121 (see Figure 4 ) of the polarization axis. In each figure, an arrow indicates the original polarization axis direction. In addition, white indicates the area where the polarization axis deviation is less than ±0.5°, and the shaded area indicates the area where the polarization axis deviation exceeds ±0.5°.

[0079] like Figure 8 As shown, when the longitudinal direction of the line 135 is parallel to the longitudinal direction of the light source 121 (X direction), a region with a large deviation of the polarization axis occurs at the end of the irradiation region. Figure 11Schematic diagram showing light incident from the light source 121 and the condenser 122 to the polarization element unit 123. It should be noted that the condenser 122 is omitted from the illustration. As shown in the figure, light (arrow L1 in the figure) is equally incident from all directions to the polarization element 132 located in the center of the polarization element unit 123. On the other hand, the direction of light (arrow L2 in the figure) incident on the polarization element 132 located at the end of the polarization element unit 123 is limited. Therefore, as shown in FIG. Figure 11 As shown, a region with a large deviation of the polarization axis occurs at the end of the irradiation region.

[0080] like Figure 9 As shown, when the longitudinal direction of the wire 135 is perpendicular to the longitudinal direction of the light source 121 (Y direction), the region where the deviation of the polarization axis is large becomes larger. Figure 10 As shown, when the longitudinal direction of line 135 forms a 45° angle with the longitudinal direction of light source 121, the region with significant polarization axis deviation becomes particularly large. Large deviations in the polarization axis can lead to image unevenness, for example, when manufacturing alignment films for liquid crystal displays (LCDs). In contrast, polarized light irradiation device 100 can suppress polarization axis deviation by adopting the following configuration.

[0081] [Details of the Polarization Element Unit]

[0082] As described above, the polarization element unit 123 has a structure that suppresses the shift (deviation) of the polarization axis. Figure 12 and Figure 13 is a schematic diagram showing the structure. Figure 12 In the figure, the support mechanism of the frame 131 and the polarizing element 132 is omitted.

[0083] like Figure 12 As shown, the polarization element 132 included in the polarization element unit 123 includes a polarization element 132A and a polarization element 132B. The polarization element 132A is located in the center of the polarization element unit 123 in the long axis direction (X direction) of the light source 121, and the polarization element 132B is located at both ends of the polarization element unit 123 in the long axis direction (X direction) of the light source 121.

[0084] exist Figure 12In the embodiment, the three polarizers 132 located in the center are polarizers 132A, and the two polarizers 132 located at each end are polarizers 132B, but the present invention is not limited thereto. In the polarizer unit 123, one or more polarizers 132 located at each end in the long axis direction (X direction) of the light source 121 can be polarizers 132B, and the remaining polarizers 132 can be polarizers 132A.

[0085] The width of polarizing element 132A along the long axis direction (X direction) of light source 121 is defined as width W1, and the width of polarizing element 132B along the long axis direction (X direction) is defined as width W2. Width W2 is smaller than width W1, for example, 1 / 2 of width W1. Alternatively, width W2 may be 3 / 4 of width W1, 1 / 4 of width W1, or the like, as long as it is smaller than width W1.

[0086] Furthermore, the polarizing element 132 is configured to be rotatable about the optical axis direction (Z direction) (see Figure 7 ), but the rotatable range of the polarizing element 132B is larger than the rotatable range of the polarizing element 132A. Specifically, Figure 13 As shown, polarizer 132B is supported on frame 131 by screws 141A-C. By making the spacing between screws 141B and 141C narrower than that of polarizer 132A, the rotatable range of polarizer 132B can be increased compared to that of polarizer 132A. Furthermore, by lengthening the thread grooves of screws 141B and 141C, which support polarizer 132B, the rotatable range of polarizer 132B can also be increased compared to that of polarizer 132A. Furthermore, depending on the support structure of polarizer 132, the rotatable range of polarizer 132B can be increased compared to that of polarizer 132A.

[0087] For example, to eliminate manufacturing errors in the line 135°, the rotatable range of polarizer 132A can be set to ±0.5°. On the other hand, the rotatable range of polarizer 132B is larger, perhaps ±2°. Furthermore, the rotatable range of polarizer 132B only needs to be larger than that of polarizer 132A.

[0088] Figure 14Schematic diagram showing the rotation of the polarization element 132B. By setting the polarization element unit 123 to the above-mentioned structure, the polarization elements 132B located at both ends of the polarization element unit 123 in the long axis direction (X direction) of the light source 121 can be greatly rotated, thereby alleviating the offset of the polarization axis at the two ends. On the other hand, in the polarization element unit 123, the offset of the polarization axis corresponding to the position in the long axis direction (X direction) of the light source 121 becomes more rapidly as it approaches the two ends of the polarization element unit 123. Therefore, by rotating only the polarization elements 132 at the two ends, the change in the polarization axis becomes too large. In contrast, by making the width W2 of the polarization element 132B smaller than the width W1 of the polarization element 132A, as shown in FIG. Figure 14 As shown, the rotation angle of the polarizing element 132B can be changed stepwise, thereby appropriately canceling the shift of the polarization axis.

[0089] Thus, in the polarization element unit 123, by making the width of the polarization element 132B along the long axis direction (X direction) of the light source 121 smaller than the width of the polarization element 132A along the same direction (X direction), and by making the rotatable range of the polarization element 132B about the optical axis direction (Z direction) larger than that of the polarization element 132A, it is possible to eliminate the shift of the polarization axis at the end of the polarization element unit 123. Therefore, the polarized light irradiation unit 120 can irradiate the irradiation object 150 with polarized light having a small shift in the polarization axis over a wide area. Furthermore, since the polarized light irradiation unit 120 does not rotate together with the polarized light irradiation unit to eliminate the shift in the polarization axis (see Patent Document 2), there are fewer restrictions on the installation location.

[0090] It should be noted that, although the description has been given of a case where the long side direction of the line 135 of the polarizing element 132 is a direction forming an angle of 45° with the long side direction (X direction) of the light source 121, the long side direction of the line 135 may also be a direction parallel to the long side direction (X direction) (see FIG. Figure 2 ) or a direction perpendicular to this direction (X direction) (refer to Figure 3 In these cases, although the polarization axis is shifted (see Figure 8 and Figure 9 ) is small but exists, so by setting it to the above structure, the offset of the polarization axis can be eliminated.

[0091] In addition, the widths of the polarizing elements 132B may be different from each other. Figure 15Schematic diagram showing the width of polarizer 132B. As shown in this figure, polarizer 132B may include polarizer 132B1 located near the center of the long axis (X direction) of light source 121, and polarizer 132B2 located near the ends of the long axis (X direction). Polarizer 132B1 has a width W3 along the long axis (X direction) of light source 121, and polarizer 132B2 has a width W4 along the long axis (X direction). Width W3 is smaller than width W1 of polarizer 132A in the long axis (X direction), and width W4 is smaller than width W3.

[0092] In this way, the polarizer 132 can also be set to the polarizer 132 that is closer to the end in the long axis direction (X direction) of the light source 121, and the width in the direction (X direction) is smaller. Here, the width of the polarizer 132B is shown in a structure that becomes smaller in two stages, but the width of the polarizer 132B can also be reduced in stages of more than three stages. The same is true for the rotatable range of the polarizer 132. The more the polarizer 132 is closer to the end in the long axis direction (X direction) of the light source 121, the larger the rotatable range around the optical axis direction (Z direction).

[0093] [Regarding various structures of polarization element units]

[0094] In the above description, the polarizer 132B has a smaller width along the long axis (X direction) of the light source 121 and a larger range of rotation about the optical axis (Z direction) relative to the polarizer 132A, but it can also be either one. That is, the polarizer 132B can also have a smaller width along the long axis (X direction) of the light source 121 relative to the polarizer 132A, but the range of rotation about the optical axis (Z direction) is the same as that of the polarizer 132A. Conversely, the polarizer 132B can also have the same width along the long axis (X direction) of the light source 121 relative to the polarizer 132A, but the range of rotation about the optical axis (Z direction) is larger than that of the polarizer 132A. In these cases, the offset of the polarization axis can also be eliminated.

[0095] In the above description, the polarizer unit 123 includes the polarizer 132A located in the center of the polarizer unit 123 in the longitudinal direction (X direction) of the light source 121 and the polarizer 132B located at its ends. However, the following structure may be used instead. Figure 16is a schematic diagram of polarization element unit 123 having this structure. As shown in this figure, polarization element unit 123 may also include polarization element 132C and polarization element 132D. Polarization element 132D is located in the center of polarization element unit 123 in the long axis direction (X direction) of light source 121, and polarization element 132C is a polarization element 132 other than polarization element 132D.

[0096] Polarizer 132C has a width W1 along the long axis direction (X direction) of light source 121, and polarizer 132D has a width W5 along this direction (X direction). Width W5 is a width smaller than width W1, for example, a width of 1 / 2 of width W1. In addition, width W5 can be 3 / 4 of width W1 or 1 / 4 of width W1 as long as it is smaller than width W1. Moreover, the rotatable range of polarizer 132D around the optical axis direction (Z direction) is larger than that of polarizer 132C. According to this structure, when the polarization axis is offset in the central portion of polarizer unit 123, the offset of the polarization axis can be eliminated by the rotation angle of polarizer 132D. The offset of the polarization axis at the central portion of polarizer unit 123 may be caused by the influence of the support structure of polarizer unit 123, etc.

[0097] In this case, the number of polarizing elements 132D is not limited to two, and may be one or more. In addition, the polarizing element 132D may differ from the polarizing element 132C only in one of the width along the long axis direction (X direction) of the light source 121 and the rotatable range around the optical axis direction (Z direction).

[0098] Furthermore, not limited to the end or center portion of the polarization element unit 123, in the polarization element 132 at a location where the polarization axis shift occurs, by making the width along the long axis (X direction) of the light source 121 smaller than that of other polarization elements, or by making the range of rotation about the optical axis (Z direction) larger than that of other polarization elements, the polarization axis shift can be eliminated. Furthermore, in the polarization element 132 at a location where the polarization axis shift occurs, by making the width along the long axis (X direction) of the light source 121 smaller than that of other polarization elements, and by making the range of rotation about the optical axis (Z direction) larger than that of other polarization elements, the polarization axis shift can be eliminated with higher precision.

[0099] [About this disclosure]

[0100] It is also possible to combine at least two of the characteristic features of the present technology described above. That is, the various characteristic features described in each embodiment can be arbitrarily combined without distinguishing between the various embodiments. In addition, the various effects described above are merely illustrative and not restrictive, and other effects may be exerted.

[0101] Label Description

[0102] 110… conveying mechanism;

[0103] 120 ... polarized light irradiation unit;

[0104] 121…light source;

[0105] 122…condenser;

[0106] 123…polarization element unit;

[0107] 131…frame;

[0108] 132… polarization element;

[0109] 133…Substrate;

[0110] 134…wire grid;

[0111] 135… line;

[0112] 150…Irradiate the object.

Claims

1. A polarization element unit that polarizes incident light, wherein: have: a frame having an opening with a first direction as a long side direction and a second direction perpendicular to the first direction as a short side direction; and A plurality of wire grid polarization elements are arranged along the first direction in the opening, and the wire grid polarization elements are supported on the frame in a manner such that they can rotate about a third direction orthogonal to the first direction and the second direction. At least one of the plurality of wire grid polarization elements has a smaller width in the long side direction or a larger rotation range about the third direction than other wire grid polarization elements in the plurality of wire grid polarization elements.

2. The polarization element unit according to claim 1, wherein At least one wire grid polarization element has a smaller width in the longitudinal direction and a larger rotatable range around the third direction than the other wire grid polarization elements.

3. The polarization element unit according to claim 1, wherein Among the plurality of wire grid polarization elements, the width of the wire grid polarization element located at the end in the longitudinal direction is smaller than the width of the wire grid polarization element located at the center in the longitudinal direction.

4. The polarization element unit according to claim 3, wherein Among the plurality of wire grid polarization elements, the rotatable range of the wire grid polarization element located at the end in the longitudinal direction is larger than the rotatable range of the wire grid polarization element located at the center in the longitudinal direction.

5. The polarization element unit according to claim 3, wherein Among the plurality of wire grid polarization elements, the closer the wire grid polarization element is to an end in the longitudinal direction, the smaller the width in the longitudinal direction. The polarization element unit according to claim 1 , wherein: Among the plurality of wire grid polarization elements, the rotatable range of the wire grid polarization element located at the end in the longitudinal direction is larger than the rotatable range of the wire grid polarization element located at the center in the longitudinal direction.

7. The polarization element unit according to claim 6, wherein Among the plurality of wire grid polarization elements, the width of the wire grid polarization element located at the end in the longitudinal direction is smaller than the width of the wire grid polarization element located at the center in the longitudinal direction.

8. The polarization element unit according to claim 6, wherein Among the plurality of wire grid polarization elements, the closer the wire grid polarization element is to an end in the longitudinal direction, the larger the rotatable range is.

9. The polarization element unit according to claim 1, wherein The extending direction of the wires of each of the wire grid polarization elements is not parallel to the longitudinal direction and is not orthogonal to the longitudinal direction.

10. The polarization element unit according to claim 9, wherein An extending direction of the wires of each of the wire grid polarization elements forms an angle of 45° with respect to the longitudinal direction.

11. A polarized light irradiation unit, emitting polarized light, wherein: have: light source; a frame fixed relative to the light source; and A plurality of wire grid polarization elements are arranged along the long side direction of the light source, and each of the wire grid polarization elements is supported on the frame in a manner such that it can rotate around the optical axis direction of the light incident from the light source. At least one of the plurality of wire grid polarization elements has a smaller width in the long side direction or a larger rotation range around the optical axis direction than other wire grid polarization elements in the plurality of wire grid polarization elements.

12. A polarized light irradiation device for irradiating a polarized light onto an irradiation object, wherein: have: A polarized light irradiation unit comprising: a light source; a frame fixed relative to the light source; and a plurality of wire grid polarization elements arranged along the longitudinal direction of the light source, wherein the wire grid polarization elements are supported on the frame in a manner rotatable around the optical axis direction of light incident from the light source, and at least one of the plurality of wire grid polarization elements has a smaller width in the longitudinal direction or a larger range of rotation around the optical axis direction than other wire grid polarization elements in the plurality of wire grid polarization elements; and The transport mechanism transports the irradiation object.

13. A polarized light irradiation method, comprising irradiating a polarized light onto an irradiation object, wherein: Light from a light source is caused to enter a polarization element unit, the polarization element unit comprising: a frame fixed relative to the light source; and a plurality of wire grid polarization elements arranged along the longitudinal direction of the light source, wherein the wire grid polarization elements are supported by the frame in a manner rotatable around the optical axis direction of the light incident from the light source, and at least one of the plurality of wire grid polarization elements has a smaller width in the longitudinal direction or a larger rotatable range around the optical axis direction than the other wire grid polarization elements among the plurality of wire grid polarization elements.

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