Polarization element unit, polarized light irradiation unit, polarization light irradiation device and polarized light irradiation method

Abstract

To provide a polarization element unit, polarized light irradiation unit, polarized light irradiation device and polarized light irradiation method that can irradiate an extensive area with polarized light small in deviation from a polarization optical axis.SOLUTION: A polarization element unit according to one embodiment of the present invention is the polarization element unit that polarizes incident light, and comprises a frame and a plurality of wire-grid polarization elements. The frame is fixed with respect to a light source. The plurality of wire-grid polarization elements is the plurality of wire-grid polarization elements that is arrayed along a longitudinal direction of the light source, in which each of the wire-grid polarization elements is supported by the frame rotatably around an optical axis direction of light to be incident from the light source. At least one of the wire-grid polarization elements is small in a width in the longitudinal direction, or large in a rotatable range around the optical axis direction, in comparison to the other wire-grid polarization elements.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] There is a technology called photo-alignment, which aligns an object, such as an alignment film of a liquid crystal panel, by irradiating it with polarized light of a predetermined wavelength. A polarized light irradiation device that combines a rod-shaped lamp and a wire-grid polarizer is known for photo-aligning a long, strip-shaped object (see, 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 object, thereby performing a photo-alignment process.

[0003] A wire grid polarizer is a device in which metal wires, such as aluminum wires, are arranged parallel to each other on quartz glass. When a wire grid polarizer is inserted into an electromagnetic wave, the polarized component parallel to the longitudinal direction of the wire grid is reflected, while the polarized component perpendicular to this direction passes through. Since the orientation direction in the irradiated object depends on the direction of the polarization axis of the polarized light incident on the irradiated object, uniformity of the polarization axis is important.

[0004] Here, because the rod-shaped lamp is a diffused light source, if the longitudinal direction of the rod-shaped lamp is taken as the left-right direction, light is incident on the wire-grid polarizer near the center of the lamp from directly above and from the left and right directions. On the other hand, light is not incident on the wire-grid polarizer at the end of the lamp from the left or right. As a result, the polarization axis of the polarized light emitted from the wire-grid polarizer at the end of the lamp is significantly misaligned (varied), and polarized light with a misaligned (varied) polarization axis is irradiated at the edge of the area irradiated with polarized light. In particular, if the longitudinal direction of the wire grid is at a 45° angle to the longitudinal direction of the rod-shaped lamp, the area irradiated with polarized light with a misaligned polarization axis becomes large.

[0005] For this reason, a polarized light irradiation device has been developed in which the polarized light irradiation unit, which includes a rod-shaped lamp and a wire-grid polarizer, can be rotated relative to the object to be irradiated (for example, Patent Document 2). With this configuration, it is possible to change the longitudinal direction of the wire grid relative to the object to be irradiated while keeping the longitudinal direction of the rod-shaped lamp and the longitudinal direction of the wire grid aligned, making it possible to suppress areas that are irradiated with polarized light with a misaligned polarization axis. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-133498 [Patent Document 2] Japanese Patent Application Laid-Open No. 2006-126464 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when the polarized light irradiation unit is rotated as described in Patent Document 2, space is required for rotation, limiting the locations where it can be installed. Furthermore, rotating the polarized light irradiation unit changes the distance and angle from the object to be irradiated, which may affect the irradiation conditions of the polarized light. For this reason, there is a demand for a polarized light irradiation unit that can irradiate a wide area with polarized light with little deviation (variation) of the polarization axis without being restricted by installation location restrictions.

[0008] 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 that are capable of irradiating polarized light with little deviation of the polarization axis over a wide area. [Means for solving the problem]

[0009] In order to achieve the above object, a polarization element unit according to one aspect 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. The frame is fixed relative to the light source. The plurality of wire-grid polarization elements are arranged along the longitudinal direction of the light source, and each of the wire-grid polarization elements is supported by the frame so as to be rotatable around the optical axis direction of 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.

[0010] With this configuration, by rotating each wire-grid polarization element around the optical axis direction of light incident from the light source, it is possible to eliminate deviations (variations) in the polarization axis of light on the irradiation surface that has passed through the polarization element unit. In this case, by reducing the width or increasing the range of rotation of at least one wire-grid polarization element, it becomes easy to eliminate deviations in the polarization axis depending on the position of the wire-grid polarization element.

[0011] At least one of the wire-grid polarizers may have a smaller width in the longitudinal direction and a larger range of rotation around the optical axis direction than the other wire-grid polarizers.

[0012] The plurality of wire-grid polarizers may be arranged such that the width in the longitudinal direction of the wire-grid polarizers located at the ends in the longitudinal direction is smaller than the width in the longitudinal direction of the wire-grid polarizers located in the center in the longitudinal direction.

[0013] The plurality of wire-grid polarizers may be arranged such that the rotatable range of the wire-grid polarizers located at the ends in the longitudinal direction is greater than the rotatable range of the wire-grid polarizers located in the center in the longitudinal direction.

[0014] The wire-grid polarizers may have a smaller width in the longitudinal direction as the wire-grid polarizers are closer to the ends in the longitudinal direction.

[0015] The plurality of wire-grid polarizers may have a larger rotatable range as the wire-grid polarizers are closer to the ends in the longitudinal direction.

[0016] The extension direction of the wires of each of the wire grid polarizers may be neither parallel to the longitudinal direction nor perpendicular to the longitudinal direction.

[0017] The extension direction of the wires of each of the wire grid polarizers may be at an angle of 45° to the longitudinal direction.

[0018] In order to achieve the above object, a polarization element unit according to one aspect of the present invention is a polarized light irradiation unit that emits polarized light, and includes a light source, a frame, and a plurality of wire-grid polarization elements. The frame is fixed relative to the light source. The wire-grid polarizers are a plurality of wire-grid polarizers arranged along the longitudinal direction of the light source, each of which is supported by the frame so as to be rotatable around the optical axis direction of light incident from the light source, and at least one of the wire-grid polarizers has a smaller width in the longitudinal direction or a larger range of rotation around the optical axis direction than the other wire-grid polarizers.

[0019] In order to achieve the above object, a polarized light irradiation device according to one aspect of the present invention includes a polarized light irradiation unit and a transport mechanism. The polarized light irradiation unit includes a light source, a frame fixed to the light source, and a plurality of wire-grid polarization elements arranged along the longitudinal direction of the light source, each of which is supported by the frame so as to be rotatable around the optical axis direction of 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. The transport mechanism transports the irradiation object.

[0020] In order to achieve the above object, a polarized light irradiation method according to one aspect of the present invention is a polarized light irradiation method for irradiating an irradiation object with polarized light, the method comprising: Light from the light source is incident on a polarization element unit comprising: a frame fixed to a light source; and a plurality of wire-grid polarization elements arranged along the longitudinal direction of the light source, each of the wire-grid polarization elements being supported by the frame so as to be rotatable around the optical axis direction of light incident from the light source, and at least one of the wire-grid polarization elements having 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. [Effects of the Invention]

[0021] According to the present invention, it is possible to provide a polarization element unit, a polarized light irradiation unit, a polarized light irradiation device, and a polarized light irradiation method that are capable of irradiating a wide area with polarized light with little deviation in the polarization axis. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic diagram of a polarized light irradiation device according to an embodiment of the present invention. [Figure 2] 3 is a schematic diagram of a polarization element unit included in the polarized light irradiation device. FIG. [Figure 3] 3 is a schematic diagram of a polarization element unit included in the polarized light irradiation device. FIG. [Figure 4] 3 is a schematic diagram of a polarization element unit included in the polarized light irradiation device. FIG. [Figure 5] 3A and 3B are schematic diagrams illustrating a support mechanism for a polarizing element in the polarizing element unit. [Figure 6] 3A and 3B are schematic diagrams illustrating a support mechanism for a polarizing element in the polarizing element unit. [Figure 7] 3A and 3B are schematic diagrams illustrating a support mechanism for a polarizing element in the polarizing element unit. [Figure 8]10 is a graph showing variations in the polarization axis on the light irradiation surface of the polarized light irradiation device. [Figure 9] 10 is a graph showing variations in the polarization axis on the light irradiation surface of the polarized light irradiation device. [Figure 10] 10 is a graph showing variations in the polarization axis on the light irradiation surface of the polarized light irradiation device. [Figure 11] 3A and 3B are schematic diagrams showing light incident on the polarization element unit. [Figure 12] 4A and 4B are schematic diagrams illustrating a configuration for suppressing deviation of the polarization axis in the polarization element unit. [Figure 13] 4A and 4B are schematic diagrams illustrating a configuration for suppressing deviation of the polarization axis in the polarization element unit. [Figure 14] 5A and 5B are schematic diagrams showing rotation of a polarizing element in the polarizing element unit. [Figure 15] 4 is a schematic diagram showing the width of a polarizing element in the polarizing element unit. FIG. [Figure 16] FIG. 10 is a schematic diagram of a polarization element unit having another configuration according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0023] A light source device according to an embodiment of the present invention will be described.

[0024] [Configuration of polarized light irradiation device] 1 is a schematic diagram showing the configuration of a polarized light irradiation device 100 according to this embodiment. As shown in the figure, the polarized light irradiation device 100 has a transport mechanism 110 and a polarized light irradiation unit 120.

[0025] 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. The irradiation object 150 is, for example, a long strip as shown in FIG. 1, wound around rolls 111 and 112 of the transport mechanism 110, and transported by the rotation of these rolls. Note that the irradiation object 150 is not limited to a long strip, and the transport mechanism 110 is not limited to the one shown here.

[0026] Polarized light irradiation unit 120 is a unit that irradiates polarized light onto irradiation object 150. As shown in FIG.

[0027] Light source 121 has a shape that is elongated in one direction and emits light. Hereinafter, the longitudinal direction of light source 121 is referred to as the X direction. Furthermore, if the direction in which irradiation target 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, the direction perpendicular to the X direction and the Y direction is referred to as the Z direction. The Z direction coincides with the optical axis direction of light incident from light source 121 to polarized light irradiation unit 120.

[0028] The light source 121 is a rod-shaped lamp with the X direction as its longitudinal direction, and can be a high-pressure mercury lamp, a metal halide lamp, etc. The light source 121 may also be a light-emitting element such as an LED (Light Emitting Diode) or an LD (Laser Diode), in which case the light source 121 may be a plurality of light-emitting elements arranged linearly along the X direction.

[0029] Collecting mirror 122 is disposed on the opposite side of light source 121 from irradiation object 150, and reflects light incident from light source 121 toward irradiation object 150. Collecting mirror 122 can have a curvature in the Y direction and a curved surface extending in the X direction, as shown in FIG. 1 . Any other type of collecting mirror 122 may be used as long as it reflects light incident from light source 121 toward irradiation object 150. Note that when light source 121 is a light-emitting element, for example, collecting mirror 122 is not necessarily provided.

[0030] The polarization element unit 123 polarizes the light incident from the light source 121 and the collecting mirror 122 to generate polarized light. Figure 2 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.

[0031] The frame 131 is fixed to the light source 121 directly or via another member, and supports a plurality of polarizing elements 132. The frame 131 may be in a frame-like shape having an opening 131a with the X direction as the longitudinal direction and the Y direction as the lateral direction. The frame 131 may also have another shape or may be made up of a plurality of members.

[0032] The polarizing element 132 includes a wire grid and polarizes incident light. It is also referred to as a wire-grid polarizing element. As shown in FIG. 2, 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. As shown in FIG. 2, the wire grid 134 is a grid formed of multiple parallel wires 135. Each wire 135 is a linear conductor and is formed on the substrate 133. The wires 135 may be made of, for example, a metal such as chromium or aluminum, a metal oxide such as titanium oxide, zirconium oxide, hafnium oxide, or yttrium oxide, or a metal nitride such as titanium nitride. The pitch P of the wires 135 is preferably equal to or less than the wavelength of the incident light, and more preferably equal to or less than one-third of the wavelength. As shown in FIG. 2, multiple 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.

[0033] The longitudinal direction of the wire 135 is not limited to the X direction, i.e., a direction parallel to the longitudinal direction of the light source 121, as shown in FIG. 2. FIGS. 3 and 4 are schematic diagrams showing other configurations of the polarizing element 132. As shown in FIG. 3, the longitudinal direction of each polarizing element 132 may be a direction (Y direction) perpendicular to the longitudinal direction (X direction) of the light source 121. As shown in FIG. 4, the longitudinal direction of each polarizing element 132 may be a direction that is not parallel to the longitudinal direction (X direction) of the light source 121 and not perpendicular to the longitudinal direction (X direction), specifically, a direction that forms an angle of 45° with respect to the longitudinal direction (X direction) of the light source 121 (direction D1 in the figure). The angle between the longitudinal direction of the wire 135 and the longitudinal direction (X direction) of the light source 121 is not limited to 45° and can be any angle.

[0034] The polarizing element 132 is created using lithography and etching techniques on a glass wafer as a substrate, but there is a limit to the size of the substrate that can be processed by processing equipment such as a vapor deposition equipment, a lithography equipment, and an etching equipment, and there is also a limit to the size of the polarizing element 132 cut out from the substrate. Therefore, when a light source that is long in one direction, such as the light source 121, is used, a plurality of polarizing elements 132 can be arranged side by side in the frame 131 as shown in Figures 2 to 4 to form a polarizing element that is long in one direction.

[0035] The number of polarizing elements 132 included in the polarizing element unit 123 is not particularly limited, and can be set according to the length (X direction) of the light source 121 and the size of each polarizing element 132. Specifically, it is preferable that the total length (X direction) of the multiple polarizing elements 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 polarizing elements 132 are squares with sides of 100 mm, the number of polarizing elements 132 is preferably 10.

[0036] The polarization element unit 123 further has a configuration for suppressing deviation (variation) of the polarization axis, the details of which will be described later.

[0037] [Support structure for polarizing elements] 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 light incident from the light source 121. Fig. 5 is a plan view showing the support structure for one polarizing element 132 on the frame 131, and Fig. 6 is a side view thereof. Fig. 7 is a schematic diagram showing the rotation of the polarizing element 132 by the same support structure.

[0038] 5 and 6, frame 131 is provided with screw holes 131b, and screws 141A to 141C are inserted into screw holes 131b. Polarizing element 132 is supported by frame 131 by being sandwiched between screws 141A to 141C. Specifically, if one side surface (XZ plane) of polarizing element 132 is side surface 136 and the opposite side surface (XZ plane) is side surface 137, screw 141A abuts the center of side surface 136, screw 141B abuts the left side of the center of side surface 137, and screw 141C abuts the right side of the center of side surface 137. In this state, by pushing and pulling screws 141B and 141C, polarizing element 132 rotates around screw 141A as a fulcrum, as shown in FIG. 7, that is, rotates around the optical axis direction (Z direction).

[0039] In this way, by making polarizing element 132 rotatable about the optical axis direction (Z direction) of light incident from light source 121, it is possible to fine-tune the longitudinal direction of wire 135. Although an error may occur in the longitudinal direction of wire 135 during manufacturing, such an error can be eliminated by rotating polarizing element 132 relative to the frame. The rotation range of polarizing element 132 required to eliminate the error is approximately ±0.5°.

[0040] The multiple polarizing elements 132 are supported by the frame 131 so that they alternate between upper and lower rows with their ends overlapping. This prevents gaps from forming between adjacent polarizing elements 132 even when the polarizing elements 132 are rotated. This is because if gaps form between adjacent polarizing elements 132, unpolarized light would leak through the gaps. Instead of arranging the polarizing elements 132 in two rows, one above the other, the polarizing elements 132 may be arranged spaced apart, and the gaps between the polarizing elements 132 may be covered with a light-shielding member.

[0041] The support structure of the polarizing elements 132 relative to the frame 131 is not limited to that described above, and it is sufficient that each polarizing element 132 is supported by the frame 131 so as to be rotatable around the optical axis direction (Z direction) of the light incident from the light source 121.

[0042] [Operation of polarized light irradiation device] The operation of the polarized light irradiation device 100 will be described. As shown in FIG. 2, the polarizing element 132 is configured such that the longitudinal direction of the wire 135 is parallel to the longitudinal 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 either directly or after being reflected by the focusing mirror 122. When the polarizing element 132 is present in the light path, most of the polarized component of the light that is parallel to the longitudinal direction of the wire 135 (X direction in FIG. 2) is reflected by the wire grid 134, while the polarized component that is orthogonal to the same direction (X direction in FIG. 2) is transmitted through the wire grid 134. As a result, a region 151 is formed in the irradiation object 150 where polarized light whose polarization axis direction is perpendicular to the longitudinal direction of the wire 135 (X direction in FIG. 1) (Y direction in FIG. 1).

[0043] 3, polarizing element 132 may be configured such that the longitudinal direction of wire 135 is orthogonal to the longitudinal direction of light source 121 (Y direction). In this case, of the light incident on polarizing element 132, most of the polarized light component parallel to the longitudinal direction of wire 135 (Y direction in FIG. 3) is reflected by wire grid 134, while the polarized light component orthogonal to the same direction (Y direction in FIG. 3) is transmitted through wire grid 134. As a result, region 152 is formed in irradiation object 150, where polarized light having a polarization axis direction perpendicular to the longitudinal direction of wire 135 (Y direction in FIG. 1) is irradiated.

[0044] 4, polarizing element 132 may be configured such that the longitudinal direction of wire 135 is oriented in direction D1 at an angle of 45° with respect to the longitudinal direction of light source 121. In this case, of the light incident on polarizing element 132, most of the polarized light component parallel to the longitudinal direction of wire 135 (direction D1 in FIG. 4) is reflected by wire grid 134, while the polarized light component perpendicular to the same direction (direction D1 in FIG. 4) is transmitted through wire grid 134. As a result, region 153 is formed in irradiation object 150, where polarized light having a polarization axis direction perpendicular to the longitudinal direction of wire 135 (direction D1 in FIG. 1) (direction D2 in FIG. 1).

[0045] When the irradiation object 150 is an alignment film used in a liquid crystal panel or the like, the alignment direction of the alignment film depends on the polarization axis direction of the polarized light irradiated onto the alignment film. The alignment direction to be generated in the alignment film varies depending on the application and type of alignment film, the type of liquid crystal panel, the design rules of the liquid crystal panel manufacturer, etc., and various alignment directions are required, as shown in the above-mentioned regions 151 to 153 (see FIG. 1). For this reason, various alignment directions can be realized by preparing polarizing elements 132 in which the longitudinal direction of wire 135 is at 90° or 45° to the side, and attaching the polarizing element 132 to the frame 131 according to the purpose.

[0046] [About the variation in polarization axis] When polarized light is irradiated onto the irradiation target 150 using the polarized light irradiation device 100, the polarization axis may vary. Figures 8 to 10 are graphs showing the variation in the polarization axis on the light irradiation surface of the polarized light irradiation device 100. Figure 8 shows the variation in the polarization axis when the longitudinal direction of the wire 135 is parallel to the longitudinal direction of the light source 121 (X direction) (see Figure 2), Figure 9 shows the variation in the polarization axis when the longitudinal direction of the wire 135 is perpendicular to the longitudinal direction of the light source 121 (Y direction) (see Figure 3), and Figure 10 shows the variation in the polarization axis when the longitudinal direction of the wire 135 is at an angle of 45° to the longitudinal direction of the light source 121 (direction D1) (see Figure 4). In each figure, the original polarization axis direction is indicated by an arrow. Regions where the variation in the polarization axis is ±0.5° or less are indicated in white, and regions where the variation in the polarization axis exceeds ±0.5° are indicated by diagonal lines.

[0047] As shown in FIG. 8, when the longitudinal direction of wire 135 is parallel to the longitudinal direction of light source 121 (X direction), regions with large variations in polarization axis occur at the ends of the irradiation region. FIG. 11 is a schematic diagram showing light incident on polarization element unit 123 from light source 121 and focusing mirror 122. Note that focusing mirror 122 is not shown. As shown in the figure, light (indicated by arrow L1 in the figure) is incident evenly from all directions on polarization element 132 located in the center of polarization element unit 123. On the other hand, the direction in which light (indicated by arrow L2 in the figure) is incident on polarization element 132 located at the end of polarization element unit 123 is limited. For this reason, as shown in FIG. 11, regions with large variations in polarization axis occur at the ends of the irradiation region.

[0048] As shown in FIG. 9, when the longitudinal direction of wire 135 is perpendicular to the longitudinal direction of light source 121 (Y direction), the region with large variations in polarization axis becomes even larger. Furthermore, as shown in FIG. 10, when the longitudinal direction of wire 135 is at an angle of 45° with the longitudinal direction of light source 121, the region with large variations in polarization axis becomes particularly large. If the variations in polarization axis become large, for example, when producing an alignment film for a liquid crystal display, the contrast of the liquid crystal display will vary depending on the location, causing problems such as unevenness in the image. In response to this, polarized light irradiation device 100 can suppress variations in polarization axis by using the following configuration.

[0049] [Details about the polarization element unit] As described above, the polarization element unit 123 has a configuration that suppresses deviation (variation) of the polarization axis. Figures 12 and 13 are schematic diagrams showing this configuration. Note that the support mechanisms for the frame 131 and the polarization element 132 are not shown in Figure 12.

[0050] 12, the polarizing element 132 included in the polarizing element unit 123 includes a polarizing element 132A and a polarizing element 132B. The polarizing element 132A is the polarizing element 132 located at the center of the polarizing element unit 123 in the long axis direction (X direction) of the light source 121, and the polarizing element 132B is the polarizing element 132 located at both ends of the polarizing element unit 123 in the long axis direction (X direction) of the light source 121.

[0051] 12, the three polarizing elements 132 located in the center are polarizing elements 132A, and the two polarizing elements 132 located at both ends are polarizing elements 132B, but this is not limited to this. One or more polarizing elements 132 located at both ends in the long-axis direction (X direction) of the light source 121 of the polarizing element unit 123 can be polarizing elements 132B, and the remaining polarizing elements 132 can be polarizing elements 132A.

[0052] 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 same direction (X direction) is defined as width W2. Width W2 is smaller than width W1, for example, 1 / 2 the width of width W1. Furthermore, width W2 may be any width smaller than width W1, such as 3 / 4 or 1 / 4 the width W1.

[0053] Furthermore, although the polarizing element 132 is configured to be rotatable around the optical axis direction (Z direction) (see FIG. 7), the rotatable range of the polarizing element 132B is larger than that of the polarizing element 132A. Specifically, as shown in FIG. 13, the polarizing element 132B is supported on the frame 131 by screws 141A-C. By narrowing the distance between the screws 141B and 141C compared to the distance between the screws 141B and 141C for the polarizing element 132A, the rotatable range of the polarizing element 132B can be made larger than that of the polarizing element 132A. Furthermore, by increasing the length of the thread grooves of the screws 141B and 141C used to support the polarizing element 132B, the rotatable range of the polarizing element 132B can be made larger than that of the polarizing element 132A. Additionally, depending on the support structure of the polarizing element 132, the rotatable range of the polarizing element 132B can be made larger than that of the polarizing element 132A.

[0054] For example, the rotation range of polarizing element 132A can be ±0.5° to eliminate manufacturing errors of wire 135°. On the other hand, the rotation range of polarizing element 132B can be larger, ±2°. Alternatively, the rotation range of polarizing element 132B may be any range as long as it is larger than the rotation range of polarizing element 132A.

[0055] FIG. 14 is a schematic diagram showing the rotation of the polarizing element 132B. By configuring the polarizing element unit 123 as described above, the polarizing elements 132B located at both ends of the polarizing element unit 123 in the long-axis direction (X direction) of the light source 121 can be rotated significantly, thereby reducing the deviation of the polarization axis at both ends. Meanwhile, in the polarizing element unit 123, the deviation of the polarization axis according to the position in the long-axis direction (X direction) of the light source 121 rapidly increases as one approaches both ends of the polarizing element unit 123. Therefore, simply rotating the polarizing elements 132 at both ends results in excessively large changes in the polarization axis. In contrast, by making the width W2 of the polarizing element 132B smaller than the width W1 of the polarizing element 132A, the rotation angle of the polarizing element 132B can be changed stepwise as shown in FIG. 14, thereby making it possible to appropriately eliminate the deviation of the polarization axis.

[0056] In this way, in polarization element unit 123, the width of polarization element 132B along the major axis direction (X direction) of light source 121 is made smaller than the width of polarization element 132A along the same direction (X direction), and the rotatable range of polarization element 132B around the optical axis direction (Z direction) is made larger than the rotatable range of polarization element 132A, thereby eliminating misalignment of the polarization axis at the end of polarization element unit 123. Therefore, polarized light irradiation unit 120 can irradiate a wide area of irradiation target 150 with polarized light with little misalignment of the polarization axis. Furthermore, because polarized light irradiation unit 120 does not rotate the entire polarized light irradiation unit to eliminate misalignment of the polarization axis (see Patent Document 2), there are fewer restrictions on the installation location.

[0057] In the above description, the polarizing element 132 is described as one in which the longitudinal direction of the wire 135 is in a direction that forms an angle of 45° with the longitudinal direction (X direction) of the light source 121, but the longitudinal direction of the wire 135 may be in a direction parallel to the same direction (X direction) (see FIG. 2) or in a direction perpendicular to the same direction (X direction) (see FIG. 3). In these cases, there exists a small area where a deviation in the polarization axis occurs (see FIGS. 8 and 9), and therefore the above configuration can eliminate the deviation in the polarization axis.

[0058] Furthermore, the widths of the polarizing elements 132B do not have to be the same. FIG. 15 is a schematic diagram showing the width of the polarizing element 132B. As shown in the figure, the polarizing element 132B may include a polarizing element 132B1 located at the center in the long-axis direction (X direction) of the light source 121 and a polarizing element 132B2 located at the end in the same direction (X direction). The polarizing element 132B1 has a width W3 in the long-axis direction (X direction) of the light source 121, and the polarizing element 132B2 has a width W4 in the same direction (X direction). The width W3 is smaller than the width W1 of the polarizing element 132A in the same direction (X direction), and the width W4 is smaller than the width W3.

[0059] In this way, the polarizing element 132 may be configured so that the width in the long axis direction (X direction) of the light source 121 decreases as the polarizing element 132 approaches the end of the same direction (X direction). Here, a configuration in which the width of the polarizing element 132B decreases in two stages has been shown, but the width of the polarizing element 132B may also decrease in three or more stages. Similarly, the rotatable range of the polarizing element 132 may be configured so that the rotatable range around the optical axis direction (Z direction) increases as the polarizing element 132 approaches the end of the long axis direction (X direction) of the light source 121.

[0060] [Various configurations of the polarization element unit] In the above description, polarizing element 132B has a smaller width in the major axis direction (X direction) of light source 121 than polarizing element 132A and a larger range of rotation around the optical axis direction (Z direction), but only one of these may be true. That is, polarizing element 132B may have a smaller width in the major axis direction (X direction) of light source 121 than polarizing element 132A, but the same range of rotation around the optical axis direction (Z direction) as polarizing element 132A. Conversely, polarizing element 132B may have the same width in the major axis direction (X direction) of light source 121 as polarizing element 132A, but the same range of rotation around the optical axis direction (Z direction) as polarizing element 132A. In these cases, it is possible to eliminate the misalignment of the polarization axis.

[0061] Furthermore, in the above description, the polarization element unit 123 includes a polarization element 132A located in the center of the polarization element unit 123 in the long-axis direction (X direction) of the light source 121, and a polarization element 132B located at the same end. However, instead, the polarization element unit 123 may have the following configuration. FIG. 16 is a schematic diagram of a polarization element unit 123 having such a configuration. As shown in the figure, the polarization element unit 123 may include a polarization element 132C and a polarization element 132D. The polarization element 132D 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 132C is a polarization element 132 other than the polarization element 132D.

[0062] The polarizing element 132C has a width W1 along the long axis direction (X direction) of the light source 121, and the polarizing element 132D has a width W5 along the same direction (X direction). The width W5 is smaller than the width W1, for example, 1 / 2 of the width W1. The width W5 may be any value smaller than the width W1, such as 3 / 4 or 1 / 4 of the width W1. Furthermore, the range of rotation of the polarizing element 132D around the optical axis direction (Z direction) is larger than the range of rotation of the polarizing element 132C. With this configuration, if a deviation in the polarization axis occurs at the center of the polarizing element unit 123, the deviation can be eliminated by adjusting the rotation angle of the polarizing element 132D. The deviation in the polarization axis at the center of the polarizing element unit 123 may occur due to the influence of the support structure of the polarizing element unit 123, etc.

[0063] In this case, the number of polarizing elements 132D is not limited to two, and may be at least 1. Furthermore, polarizing element 132D may differ from polarizing element 132C only in either the width along the major axis direction (X direction) of light source 121 or the range of rotation around the optical axis direction (Z direction).

[0064] Furthermore, it is possible to eliminate the misalignment of the polarization axis by making the width of the polarizing element 132 along the long axis direction (X direction) of the light source 121 smaller than that of the other polarizing elements or by making the range of rotation around the optical axis direction (Z direction) larger than that of the other polarizing elements at the position where the misalignment of the polarization axis occurs, not limited to the end or center of the polarization element unit 123. Furthermore, it is possible to eliminate the misalignment of the polarization axis with higher precision by making the width of the polarizing element 132 along the long axis direction (X direction) of the light source 121 smaller than that of the other polarizing elements and by making the range of rotation around the optical axis direction (Z direction) larger than that of the other polarizing elements at the position where the misalignment of the polarization axis occurs.

[0065] [About this disclosure] It is also possible to combine at least two of the features of the present technology described above. That is, the various features described in each embodiment may be arbitrarily combined without distinction between the embodiments. Furthermore, the various effects described above are merely examples and are not limiting, and other effects may also be achieved. [Explanation of symbols]

[0066] 110...Transport mechanism 120...Polarized light irradiation unit 121...Light source 122...Condenser mirror 123...Polarizing element unit 131...frame 132...Polarizing element 133... Circuit board 134...Wire grid 135...Wire 150...Irradiation target

Claims

1. A polarization element unit that polarizes incident light, a frame fixed relative to the light source; a plurality of wire-grid polarization elements arranged along a longitudinal direction of the light source, each of the wire-grid polarization elements being supported by the frame so as to be rotatable about an optical axis direction of light incident from the light source, and at least one of the wire-grid polarization elements having a smaller width in the longitudinal direction or a larger range of rotation about the optical axis direction than the other wire-grid polarization elements; A polarization element unit comprising:

2. The polarization element unit according to claim 1 , At least one of the wire grid polarizers has a smaller width in the longitudinal direction and a larger range of rotation around the optical axis direction than the other wire grid polarizers. Polarization element unit.

3. The polarization element unit according to claim 1 , The width in the longitudinal direction of the wire grid polarizers located at the ends in the longitudinal direction is smaller than the width in the longitudinal direction of the wire grid polarizer located at the center in the longitudinal direction. Polarization element unit.

4. The polarization element unit according to claim 3 , The plurality of wire-grid polarizers are arranged such that the rotatable range of the wire-grid polarizers located at the ends in the longitudinal direction is larger than the rotatable range of the wire-grid polarizers located in the center in the longitudinal direction. Polarization element unit.

5. The polarization element unit according to claim 3 , The wire-grid polarizers have a smaller width in the longitudinal direction as they approach the ends in the longitudinal direction. Polarization element unit.

6. The polarization element unit according to claim 1 , The plurality of wire-grid polarizers are arranged such that the rotatable range of the wire-grid polarizers located at the ends in the longitudinal direction is larger than the rotatable range of the wire-grid polarizers located in the center in the longitudinal direction. Polarization element unit.

7. The polarization element unit according to claim 6, The width in the longitudinal direction of the wire grid polarizers located at the ends in the longitudinal direction is smaller than the width in the longitudinal direction of the wire grid polarizer located at the center in the longitudinal direction. Polarization element unit.

8. The polarization element unit according to claim 6, The plurality of wire-grid polarizers have a larger rotational range as the wire-grid polarizers are closer to the ends in the longitudinal direction. Polarization element unit.

9. The polarization element unit according to claim 1 , In each of the wire grid polarizers, the extending direction of the wires is not parallel to the longitudinal direction and is not perpendicular to the longitudinal direction. Polarization element unit.

10. The polarization element unit according to claim 9 , The extension direction of the wires of each of the wire grid polarizers forms an angle of 45° with respect to the longitudinal direction. Polarization element unit.

11. A polarized light irradiation unit that emits polarized light, A light source and a frame fixed relative to the light source; a plurality of wire-grid polarization elements arranged along a longitudinal direction of the light source, each of the wire-grid polarization elements being supported by the frame so as to be rotatable about an optical axis direction of light incident from the light source, and at least one of the wire-grid polarization elements having a smaller width in the longitudinal direction or a larger range of rotation about the optical axis direction than the other wire-grid polarization elements; A polarized light irradiation unit comprising:

12. A polarized light irradiation device that irradiates an irradiation object with polarized light, a polarized light irradiation unit comprising: a light source; a frame fixed to the light source; and a plurality of wire-grid polarization elements arranged along a longitudinal direction of the light source, each of the wire-grid polarization elements being supported by the frame so as to be rotatable about an optical axis direction of light incident from the light source, at least one of the wire-grid polarization elements having a smaller width in the longitudinal direction or a larger range of rotation about the optical axis direction than the other of the wire-grid polarization elements; a transport mechanism for transporting the irradiation object; A polarized light irradiation device comprising:

13. A polarized light irradiation method for irradiating an irradiation object with polarized light, comprising: Light from the light source is incident on a polarization element unit including a frame fixed to the light source and a plurality of wire-grid polarization elements arranged along the longitudinal direction of the light source, the wire-grid polarization elements being supported by the frame so as to be rotatable about the optical axis direction of light incident from the light source, and at least one of the wire-grid polarization elements having a smaller width in the longitudinal direction or a larger range of rotation about the optical axis direction than the other wire-grid polarization elements. Polarized light irradiation method.

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