JP2014134629A - Optical element and projection type image display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element that suppresses generation of warpage or the like caused by heat or humidity and prevents generation of illuminance irregularity without sticking to glass or the like, which is a factor of increase in the cost, and to provide a projection type image display device using the optical element.SOLUTION: The optical element includes a polarizer having a polarization axis in a specific direction and a support member supporting an outer periphery of the polarizer. The polarizer is fixed, at both ends in the direction of the polarization axis, to the support member, while at least a part of the periphery except for the ends above described is not fixed to the support member.

Description

  The present invention relates to an optical element and a projection display apparatus using the optical element.

  As one of the projection type video display apparatuses, there is a liquid crystal projector that projects an image based on a transmissive liquid crystal display element on a screen surface. Liquid crystal projectors are widely used because they can be used for presentations, home theaters, and the like, and can project still images or moving images in a large screen size.

  In a liquid crystal projector, an image is formed by performing image modulation with a transmissive liquid crystal display element. As a liquid crystal projector for projecting a color image on a screen, a three-plate liquid crystal projector that modulates an image using three liquid crystal panels composed of a plurality of transmissive liquid crystal display elements, or a single liquid crystal display A single-plate liquid crystal projector that performs image modulation using an element can be given.

  Polarizers for obtaining light of a predetermined polarization component are disposed on the incident side and the emission side of the transmissive liquid crystal display element of the liquid crystal projector. Light from a linearly polarized light source is linearly polarized by a polarizer disposed on the incident side, then enters a transmissive liquid crystal display element, is modulated by a video signal, and changes its polarization state. And the light which permeate | transmitted the liquid crystal display element will be in the state which the polarization state changed to the predetermined linearly polarized light component with the polarizer arrange | positioned at the output side. Thereby, an image is projected.

  Accordingly, both the incident-side and output-side polarizers are essential components in a liquid crystal projector, and the optical characteristics of these both polarizers have a great influence on the projected image. Both of these polarizers often use absorption polarizers that transmit light of a predetermined linear polarization component and absorb light of a linear polarization component orthogonal to the predetermined linear polarization component.

  An absorptive polarizer used as a polarizer of a liquid crystal projector is usually fixed to a glass made of sapphire or quartz via an adhesive or the like from the viewpoint of promoting exhaust heat and improving handling properties. The polarizer disposed near the light source is in an environment where a great deal of heat can be applied. Under such an environment where a great deal of heat can be applied, the stretched state of the polarizing layer is gradually relaxed. Since the base material on which the absorbing polarizer is fixed generates stress that tends to contract as the polarizing layer is stretched and relaxed, the glass is required to have a rigidity that does not change its shape. Therefore, when thin glass is used, it may be deformed. When the deformation occurs, the traveling direction of the light emitted from the light source is disturbed, and the quality of the image is deteriorated such as uneven brightness of the image light.

  Glass is an effective member from the viewpoint of maintaining the optical performance of the absorbing polarizer. However, when the cost of the glass itself and the processing cost for fixing are taken into consideration, the cost of the polarizer is generally high. Then, the technique of fixing an absorption type polarizer to a supporting member alone was reported (patent document 1). If the technique of patent document 1 is used, even if an absorption type polarizer is a single-piece | unit, it can fix without deformation. However, in the technique of Patent Document 1, since the end portions of the absorption polarizer are all fixed to the support member, the polarizer expands due to heat and humidity in the non-stretch direction in which the contraction due to heat is not significant. The possibility of deformation, such as bending, could not be excluded.

JP 2004-198583 A

  The present invention has been made in view of the above points, an optical element that suppresses the occurrence of deflection due to heat and humidity, and does not cause uneven brightness without being bonded to glass or the like, which causes a cost increase. An object of the present invention is to provide a projection-type image display apparatus using the above-mentioned.

  The optical element of the present invention is an optical element having a polarizer having a polarization axis in a specific direction and a support member that supports an outer peripheral portion of the polarizer, and the polarizer in the polarization axis direction of the polarizer The both end portions are fixed to the support member, and at least a part other than the both end portions is not fixed to the support member.

  In the optical element of the present invention, it is preferable that the polarizer is an absorptive polarizer, and the polarization axis direction is an absorption axis direction of the absorptive polarizer.

  In the optical element of the present invention, it is preferable that the polarizer has a line-symmetric shape having an axis of symmetry in a direction orthogonal to the polarization axis direction or a direction parallel to the polarization axis direction.

  In the optical element of the present invention, the fixing region of the support member of the polarizer at the both end portions is provided at a line-symmetric position with respect to an imaginary line orthogonal to the polarization axis direction and passing through the center of the polarizer. It is preferable that

  In the optical element of the present invention, the support member is composed of a frame body in which four long portions are connected in a square shape so as to form an opening in the center, and both end portions of the polarizer are It is preferable that the support member is fixed along the direction orthogonal to the longitudinal direction of the long portion of the support member.

  In the optical element of the present invention, the thickness of the polarizer is preferably 10 μm or more and 500 μm or less.

  In the optical element of the present invention, it is preferable that the support member is made of metal.

  The projection display apparatus of the present invention includes a light source, a display element disposed on an optical path of light emitted from the light source, and the light disposed on the light incident side and / or the light emitting side of the display element. And an optical element.

  According to the present invention, an optical element that suppresses the occurrence of deflection due to heat and humidity and does not cause unevenness of brightness without being bonded to glass or the like that causes an increase in cost, and a projection display apparatus using the optical element. Can be provided.

It is a figure which shows the optical element which concerns on embodiment of this invention. It is sectional drawing which shows the absorption type polarizer used for the optical element which concerns on embodiment of this invention. It is a figure which shows the other example of the optical element which concerns on embodiment of this invention. It is a figure which shows the other example of the optical element which concerns on embodiment of this invention. It is a figure which shows the other example of the optical element which concerns on embodiment of this invention. It is a figure which shows the other example of the optical element which concerns on embodiment of this invention. It is a figure which shows the liquid crystal projector provided with the optical element of this invention. It is a figure which shows the optical element of a comparative example.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited to the following embodiment, In the range with the effect of this invention, it can change suitably and can implement.

  FIG. 1 is a diagram showing an optical element according to an embodiment of the present invention. The optical element shown in FIG. 1 mainly includes a polarizer 2 having a polarization axis in a specific direction, and a support member 1 that supports the outer peripheral portion of the polarizer 2. In this optical element, both end portions 2 a in the polarization axis direction of the polarizer 2 are fixed to the support member 1. Further, at least a part other than both end portions 2 a of the polarizer 2 is not fixed to the support member 1.

  The polarizer 2 is an optical component that absorbs or reflects light in a predetermined polarization axis direction and transmits light in a direction orthogonal to the predetermined polarization axis direction. An example of the polarizer 2 used in the present invention is an absorptive polarizer using a resin film in which iodine or a dichroic dye is oriented. From the principle of the present invention described later, the substrate of the polarizer 2 is preferably composed of a bendable film or a resin material. Moreover, it is preferable that the thickness of the polarizer 2 is 10 micrometers-500 micrometers from a flexible viewpoint.

  The absorptive polarizer that can be used in the optical element of the present invention includes, for example, a polarizing layer 31 that exhibits a polarizing function and a protective film 32 that protects both surfaces of the polarizing layer 31, as shown in FIG. . For example, the polarizing layer 31 is impregnated with a dichroic substance in a resin material and molded into a sheet body, and then the sheet body is stretched several times in a specific direction to orient the dye molecules, and if necessary, crosslinked. It can produce by processing and sticking the protective film 32 on both surfaces of this sheet body with an adhesive agent. Thereby, a polarizing function (a function of transmitting linearly polarized light when natural light is incident) is exhibited in the polarizing layer 31, and moisture absorption and relaxation of the stretched state can be prevented by the protective film 32. In this case, the direction in which the sheet body is stretched, that is, the direction in which tension is applied to the sheet body is the polarization axis direction of the polarizing layer 31.

  As a resin material constituting the polarizing layer 31, for example, a vinyl alcohol polymer such as polyvinyl alcohol or partially formalized polyvinyl alcohol can be used. Moreover, iodine, a dichroic dye, etc. can be used as a dichroic substance. In the polarizing layer 31, since the dye molecules are oriented along the stretching direction when the sheet body is stretched, the natural light is linearly polarized by absorbing the light of the electric field vector component that swings in the direction parallel to the stretching direction. Make it transparent. Therefore, the stretching direction is generally called the absorption axis direction. Therefore, in the absorption polarizer, the absorption axis direction is the polarization axis direction.

  The protective film 32 is preferably transparent. As a material of the protective film 32, an acetate-based resin such as triacetyl cellulose can be used, but is not limited thereto. From the viewpoints of polarization characteristics and durability, a transparent protective film that can be particularly preferably used is a triacetylcellulose film whose surface is saponified with an alkaline solution or the like. In addition, when providing the protective film 32 on both surfaces of the polarizing layer 31, you may use the protective film comprised by the resin material which is mutually different on each surface.

  The protective film 32 may be subjected to a hard coat treatment, an antireflection treatment, an antisticking treatment, a diffusion treatment, an antiglare treatment, or the like as long as the object of the present invention is not impaired. Further, a fine concavo-convex structure or a dielectric layer may be provided on the protective film 32 or the polarizing layer 31 to add an antireflection function, or a functional layer having diffusibility may be provided on the protective film 32 or the polarizing layer 31. good.

  The support member 1 is composed of a frame body in which four long portions 1b and 1b 'are connected in a square shape so as to form an opening 1c in the center. The long portions 1b and 1b 'are used as regions for fixing the outer peripheral portion of the polarizer 2, and the opening 1c is used as a region for transmitting light rays. The support member 1 is necessary for fixing the polarizer 2 at a predetermined position in, for example, a projection display apparatus.

  The widths of the long portions 1b and 1b 'are not particularly limited, but may be any width as long as the polarizer 2 is fixed. The thickness of the long portions 1b and 1b ′ is rigid enough not to be deformed by the stress accompanying the contraction of the polarizer 2 described later, taking into consideration the material constituting the support member 1 and the width of the long portions 1b and 1b ′. As long as the thickness of the support member 1 is sufficient.

  Examples of the material of the support member 1 include metal materials such as aluminum, titanium, magnesium, and metal alloys, resin materials such as polycarbonate and polymethyl methacrylate, composite materials including glass fiber composite materials, and glass. In particular, it is preferable to use a metal material that is excellent in heat dissipation as the material of the support member 1 considering the durability and workability of the polarizer 2.

  As described above, in the optical element according to the present invention, both end portions 2 a in the polarization axis direction of the polarizer 2 are fixed to the support member 1, and other than both end portions 2 a of the polarizer 2 are not fixed to the support member 1. . In the configuration shown in FIG. 1, both end portions 2a of a rectangular polarizer 2 are fixed by fixing regions 1a of a pair of long portions 1b opposed to a support member 1 that is a rectangular frame. Further, the polarizer 2 is not fixed except in the fixing region 1 a of the support member 1. That is, in the support member 1, the polarizer 2 is fixed only by the fixing region 1a. In FIG. 1, both end portions 2 a of the polarizer 2 are along a direction (y direction in FIG. 1) perpendicular to the longitudinal direction (polarization axis direction) (the x direction in FIG. 1) of the long portion 1 a of the support member 1. And is fixed to the support member 1.

  In the case where the polarizer 2 is an absorptive polarizer produced by stretching (giving tension) in a specific direction as described above, stress remains in the stretching direction. This residual stress is easily relaxed when the polarizer is placed in a high temperature environment, and appears as a phenomenon of contraction in the direction in which tension is applied (stretching direction). In the case of an absorptive polarizer, as described above, the stretching direction at the time of producing the polarizing layer is the absorption axis direction (polarization axis direction), and therefore the tensioned direction is the absorption axis direction (polarization axis direction). Become.

  In the case of an absorptive polarizer, even if the protective film 32 is attached to relax the stretched state of the polarizing layer 31, it is difficult to completely suppress the shrinkage of the polarizing layer 31 in a high heat environment. In the optical element of the present invention, the polarization axis direction of the polarizer 2 (absorption axis direction (stretching direction) in the case of an absorption polarizer) is used to suppress the shrinkage of the polarizing layer 31 in a high heat environment and eliminate the occurrence of deflection. The two end portions 2a are fixed by the fixing region 1a of the support member 1.

  Here, the both end portions 2a in the polarization axis direction of the polarizer 2 mean both end portions facing each other across the main body of the polarizer 2 in the polarization axis direction among the end portions of the polarizer 2. When the polarizer 2 is an absorptive polarizer, the polarization axis direction is the stretching direction (absorption axis direction) of the stretching process when producing the polarizing layer. In the present invention, it is sufficient that at least both ends of the polarizer are fixed in the fixing region of the support member, and other than the both ends of the polarizer may be fixed to the support member. The entire outer periphery need not be fixed to the support member.

  The shape of the polarizer 2 is not particularly limited, but is a line-symmetric shape having an axis of symmetry with respect to a direction parallel to the polarization axis direction (extension direction in the case of an absorption polarizer) or a direction orthogonal to the polarization axis direction. Is preferred. For example, as shown in FIGS. 3 and 4, the polarizer 2 preferably has a line-symmetric shape having an axis of symmetry with respect to a direction A orthogonal to the polarization axis direction. By adopting such a shape, even when contraction in the direction of the polarization axis occurs, tension is uniformly applied to the entire polarizer, so that the occurrence of deflection can be more effectively suppressed.

  In the present invention, the shape of the end includes various shapes depending on the shape of the polarizer. For example, it may be a side having a predetermined length, an acute angle or an obtuse angle, or a corner having a curved shape. Further, the end portion does not necessarily mean only the side portion or the corner portion, and may include both the side portion and the corner portion.

  In the present invention, both end portions in the polarization axis direction of the polarizer are fixed to the support member. By fixing these both end portions to the support member, deformation due to thermal expansion at the end portions other than the polarization axis direction (stretching direction in the case of the absorbing polarizer) can be more effectively released, and more effectively Generation of deflection can be suppressed.

  As the positional relationship of the fixed region 1a of the support member 1, it is preferable that the position be symmetrical with respect to an imaginary line A that is orthogonal to the polarization axis direction and passes through the center of the polarizer 2, as shown in FIGS. Is preferably provided. In such a positional relationship, even if contraction in the direction of the polarization axis occurs, the tension is uniformly applied to the polarizer 2, so that the occurrence of deflection can be further suppressed.

  Further, as described above, both end portions 2a of the polarizer 2 are perpendicular to the longitudinal direction (polarization axis direction) (x direction in FIG. 1) of the long portion 1a of the support member 1 (y direction in FIG. 1). , The tension due to the contraction in the polarization axis direction is easily applied uniformly to the entire polarizer, and the occurrence of deflection can be further suppressed.

  There is no restriction | limiting in particular about the number and shape of the fixed area | region 1a of the supporting member 1. FIG. For example, as shown in FIGS. 1 and 3, the number and shape of the fixed regions 1a at the respective end portions 2a of the polarizer 2 may be the same. As shown in FIGS. The number of fixed regions 1a in the end 2a may be different for each end 2a. Further, as shown in FIGS. 1 and 3 to 5, the fixing region 1 a of the supporting member 1 may be provided only on the long portion 1 b of the supporting member 1 corresponding to both ends in the polarization axis direction. As shown in FIG. 6, the elongated portion 1b of the support member 1 corresponding to both ends in the polarization axis direction and the elongated portion 1b ′ of the support member 1 corresponding to the direction orthogonal to the polarization axis direction. A fixed region 1a may be provided. In the configuration shown in FIG. 6, it is necessary to provide a non-fixed region where the polarizer 2 is not fixed to the long portion 1 b ′ of the support member 1 corresponding to the direction orthogonal to the polarization axis direction.

  The method of fixing the polarizer 2 to the support member 1 is not limited as long as the polarizer 2 is not peeled off from the support member 1 or is not displaced. For example, a method of fixing with an adhesive, a method of sandwiching and fixing both surfaces of the polarizer 2 with a pair of support members 1, and the like can be given. In the case of fixing with an adhesive, it is preferable to use an adhesive having excellent thermal conductivity from the viewpoint of improving reliability.

  Thus, in the optical element of the present invention, both ends 2a of the polarizer 2 in the polarization axis direction of the polarizer 2 are fixed to the support member 1, and at least a part other than the both ends 2a is attached to the support member 1 at least partially. It is not fixed. For this reason, the polarizer 2 is fixed to the support member 1 even when heat is applied to the polarizer 2 in the actual use environment and the contraction in the direction of the polarization axis (for example, the stretching direction in the absorption polarizer) occurs. The contraction is canceled by the tension applied in the direction of the polarization axis. As a result, the occurrence of deflection due to thermal expansion can be suppressed, and the occurrence of uneven brightness can be prevented. Further, in this optical element, there is at least a region where the polarizer 2 is not fixed to the support member 1, so that deformation due to thermal expansion can be released in that region, which contributes to suppression of the occurrence of deflection. Therefore, according to the optical element of the present invention, the occurrence of deflection due to heat and humidity is suppressed, and the unevenness of luminance does not occur without being bonded to glass or the like which causes an increase in cost.

  A projection display apparatus according to an embodiment of the present invention will be described. As the projection display apparatus according to the present embodiment, there is a liquid crystal projector using a transmissive liquid crystal display element, and the optical element according to the above embodiment is used as a polarizer disposed at least on the incident side of the liquid crystal projector. It can be used suitably.

  FIG. 7 is a diagram showing a liquid crystal projector which is a projection type image display device including the optical element of the present invention. The liquid crystal projector shown in FIG. 7 includes a light source 11 such as an LED, an illumination optical device 12 arranged at the rear stage of the light source 11, an image synthesis optical device 13 arranged at the rear stage of the illumination optical device 12, and an image synthesis optical device. 13 and a projection optical device 14 disposed in the subsequent stage.

  In this liquid crystal projector, after the white light emitted from the light source 11 is aligned with linearly polarized light (for example, S-polarized light) in a predetermined direction by the illumination optical device 12, the blue (B) light included in the white light is the first. The first optical path L1 is separated, the green (G) light is separated into the second optical path L2, and the red (R) light is separated into the third optical path L3. Then, after forming the image light from the blue light, the green light, and the red light that are separated into the first optical path L1, the second optical path L2, and the third optical path L3 and enter the image combining optical device 13, respectively. The image light obtained by combining the color image lights is enlarged and projected on the screen by the projection optical device 14.

  The light source 11 includes a light source lamp 111 and a reflecting mirror 112 that reflects white light emitted from the light source lamp 111 and aligns it in approximately one direction. The light source lamp 111 emits white light. The reflecting mirror 112 reflects white light emitted from the light source lamp 111 toward the illumination optical device 12 along the optical path L.

  The illumination optical device 12 includes a device main body 121 arranged at the rear stage of the light source 11, a dichroic mirror 122a arranged at the rear stage of the device main body 121, and a reflection arranged on the first optical path L1 at the rear stage of the dichroic mirror 122a. A mirror 123a, a dichroic mirror 122b disposed downstream of the dichroic mirror 122a, and reflecting mirrors 123b and 123c and relay lenses 124a and 124b disposed on a third optical path L3 downstream of the dichroic mirror 122b.

  The apparatus main body 121 converts the white light emitted from the light source 11 into parallel light of linearly polarized light (for example, S-polarized light) aligned substantially in one direction via a polarization conversion element, a lens array, and a relay lens (not shown). The parallel light is emitted along the optical path L toward the dichroic mirror 122a.

The dichroic mirrors 122 a and 122 b are disposed on the optical path L from the light source 11. The dichroic mirrors 122a and 122b are configured by laminating a dielectric film such as SiO ₂ , TiO ₂ , Ta ₂ O ₃ , and MgF ₂ on a glass substrate, and transmit a specific wavelength region in the visible region, and other wavelengths. Reflect areas. In the present embodiment, dichroic mirror 122a transmits green light and red light that are in a wavelength region (for example, 495 nm or more) of visible light or more, and reflects blue light that is in a wavelength region of less than green light. To do. In addition, the dichroic mirror 122b transmits red light that has a wavelength region that is greater than or equal to visible red light (eg, 620 nm or more) and reflects green light and blue light that are less than red light.

  The main surface of the dichroic mirror 122 a is disposed with an inclination of 45 degrees with respect to the optical path L from the light source 11. The dichroic mirror 122a reflects the blue light included in the white light emitted from the apparatus main body 121 toward the reflection mirror 123a in a direction substantially perpendicular to the optical path L (upward in the drawing), and the blue light enters the first optical path L1. To separate. The reflection mirror 123a is disposed so that its main surface faces the dichroic mirror 122a, and reflects blue light toward the image combining optical device 13 in substantially the same direction as the optical path L from the light source 11 (left direction in the drawing). The dichroic mirror 122a transmits red light and green light included in white light.

  The main surface of the dichroic mirror 122 b is disposed with an inclination of 45 degrees with respect to the optical path L from the light source 11. The dichroic mirror 122b reflects the green light transmitted through the dichroic mirror 122a toward the image combining optical device 13 in a direction substantially perpendicular to the optical path L (upward in the drawing), and separates the green light into the second optical path L2. The dichroic mirror 122b transmits the red light transmitted through the dichroic mirror 122a and separates the red light into the third optical path L3.

  The main surfaces of the reflection mirrors 123b and 123c are arranged with an inclination of 45 degrees with respect to the third optical path L3. The reflection mirror 123b reflects the red light separated by the dichroic mirror 122b in a direction (upward in the drawing) perpendicular to the optical path L from the light source 11. The reflection mirror 123c reflects the red light reflected by the reflection mirror 123b toward the image combining optical device 13 in a direction substantially opposite to the optical path L from the light source 11 (right direction on the paper).

  The relay lens 124a is disposed between the dichroic mirror 122b and the reflection mirror 123b, and the relay lens 124b is disposed between the reflection mirror 123b and the reflection mirror 123c. The relay lenses 124a and 124b adjust the optical axis of the red light separated into the third optical path L3 whose optical path length is longer than the first optical path L1 and the second optical path L2, and synthesize them by the image synthesizing optical device 13. Color unevenness of the image light to be reduced.

  The image combining optical device 13 includes a relay lens 131B, an incident side polarizer 132B, a liquid crystal panel 133B, an output side polarizer 134B, which are disposed on the first optical path L1, and a relay lens, which is disposed on the second optical path L2. 131G, an incident side polarizer 132G, a liquid crystal panel 133G, and an output side polarizer 134G, a relay lens 131R, an incident side polarizer 132R, a liquid crystal panel 133R, and an output side polarizer 134R arranged on the third optical path L3; Is provided. The image synthesizing optical device 13 modulates the red light, green light, and blue light separated by the illumination optical device 12 with the liquid crystal panels 133R, 133G, and 133B to form image light, and the formed three colors of image light. The light is combined by the RGB combining dichroic prism 135 and output to the projection optical device 14.

  The projection optical device 14 is configured by combining a plurality of lenses. The projection optical device 14 enlarges and projects the image light emitted from the image synthesis optical device 13 on the screen. In such a liquid crystal projector, the incident-side polarizer suppresses the occurrence of deflection due to heat and humidity and does not cause luminance unevenness, so that high-quality image light can be projected.

Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.
Example 1
The outer shape is rectangular, the length of the long side is 34 mm, the length of the short side is 24 mm, the width of the long portion is 3 mm, the thickness of the long portion is 1 mm, and the outer shape is An absorption polarizer (manufactured by Sumitomo Chemical Co., Ltd., SRW062A) having a rectangular shape with a long side length of 30 mm, a short side length of 20 mm, and a thickness of 110 μm was prepared. At this time, the absorption axis (polarization axis) of the absorptive polarizer was parallel to the long side of the rectangle. An adhesive (Aron Alpha EXTRA 4000, manufactured by Toa Gosei Co., Ltd.) was applied to the support member, and an absorptive polarizer was attached to the support member to produce the optical element of Example 1. As shown in FIG. 1, this optical element is provided with a fixed region 1a on each of the long portions (short sides) 1b of the support member 1 orthogonal to the polarization axis direction (stretching direction) of the absorption polarizer. The two fixed regions 1a are in a positional relationship that is line-symmetric with respect to the symmetry axis A in the direction orthogonal to the polarization axis direction.

(Example 2)
Aluminum support whose outer shape is trapezoidal, the length of the lower base is 35 mm, the length of the upper base is 25 mm, the height is 25 mm, the width of the long part is 3 mm, and the thickness of the long part is 1 mm An absorption polarizer (manufactured by Sumitomo Chemical Co., Ltd., SRW062A) having a trapezoidal outer shape and a member having a trapezoidal outer shape, a lower base length of 32 mm, an upper base length of 23 mm, a height of 23 mm, and a thickness of 110 μm Got ready. At this time, the absorption axis (polarization axis) of the absorptive polarizer was parallel to the upper and lower bases of the trapezoid. An adhesive (Aron Alpha EXTRA 4000, manufactured by Toa Gosei Co., Ltd.) was applied to the support member, and an absorptive polarizer was attached to the support member to produce the optical element of Example 2. As shown in FIG. 3, this optical element is provided with a fixed region 1a at each of the long portions 1b (trapezoidal leg portions) of the support member 1 in the polarization axis direction (stretching direction) of the absorption polarizer. The two fixed regions 1a are in a positional relationship that is line-symmetric with respect to the symmetry axis A in the direction orthogonal to the polarization axis direction.

(Example 3)
Aluminum support whose outer shape is trapezoidal, the length of the lower base is 35 mm, the length of the upper base is 25 mm, the height is 25 mm, the width of the long part is 3 mm, and the thickness of the long part is 1 mm An absorption polarizer (manufactured by Sumitomo Chemical Co., Ltd., SRW062A) having a trapezoidal outer shape and a member having a trapezoidal outer shape, a lower base length of 32 mm, an upper base length of 23 mm, a height of 23 mm, and a thickness of 110 μm Got ready. At this time, the absorption axis (polarization axis) of the absorptive polarizer was parallel to the upper and lower bases of the trapezoid. An adhesive (Aron Alpha EXTRA 4000, manufactured by Toa Gosei Co., Ltd.) was applied to the support member, and an absorptive polarizer was attached to the support member to produce the optical element of Example 3. As shown in FIG. 4, the optical element has two portions on one side and one portion on the other side of the long portion 1b (trapezoidal leg portion) of the support member 1 in the polarization axis direction (stretching direction) of the absorbing polarizer. The fixed region 1a is provided, and the fixed regions 1a at both ends have a line-symmetric positional relationship with respect to the symmetry axis A in the direction orthogonal to the polarization axis direction.

(Example 4)
Aluminum support whose outer shape is trapezoidal, the length of the lower base is 35 mm, the length of the upper base is 25 mm, the height is 25 mm, the width of the long part is 3 mm, and the thickness of the long part is 1 mm An absorption polarizer (manufactured by Sumitomo Chemical Co., Ltd., SRW062A) having a trapezoidal outer shape and a member having a trapezoidal outer shape, a lower base length of 32 mm, an upper base length of 23 mm, a height of 23 mm, and a thickness of 110 μm Got ready. At this time, the absorption axis (polarization axis) of the absorptive polarizer was parallel to the upper and lower bases of the trapezoid. An adhesive (Aron Alpha EXTRA 4000, manufactured by Toa Gosei Co., Ltd.) was applied to the support member, and an absorptive polarizer was attached to the support member to produce the optical element of Example 4. As shown in FIG. 5, the optical element has two portions on one side and one portion on the other side of the long portion 1b (trapezoidal leg portion) of the support member 1 in the polarization axis direction (stretching direction) of the absorbing polarizer. The fixed region 1 a is provided, and the fixed regions 1 a at both ends are not in a line-symmetric positional relationship with respect to the symmetry axis A in the direction orthogonal to the polarization axis direction.

(Example 5)
Aluminum support whose outer shape is trapezoidal, the length of the lower base is 35 mm, the length of the upper base is 25 mm, the height is 25 mm, the width of the long part is 3 mm, and the thickness of the long part is 1 mm An absorption polarizer (manufactured by Sumitomo Chemical Co., Ltd., SRW062A) having a trapezoidal outer shape and a member having a trapezoidal outer shape, a lower base length of 32 mm, an upper base length of 23 mm, a height of 23 mm, and a thickness of 110 μm Got ready. At this time, the absorption axis (polarization axis) of the absorptive polarizer was parallel to the upper and lower bases of the trapezoid. An adhesive (Aron Alpha EXTRA 4000, manufactured by Toa Gosei Co., Ltd.) was applied to the support member, and an absorptive polarizer was attached to the support member to produce the optical element of Example 4. As shown in FIG. 6, the optical element includes a long portion 1 b (trapezoidal leg) of the support member 1 in the polarization axis direction (stretching direction) of the absorption polarizer and a polarization axis direction (stretching) of the absorption polarizer. Direction), a fixed region 1a is provided in a part of the elongated portion 1b '(upper and lower bases of the trapezoid), and the fixed regions 1a at both ends are arranged in a direction perpendicular to the polarization axis direction. The positional relationship was not line-symmetric with respect to the symmetry axis A.

(Comparative Example 1)
The outer shape is rectangular, the length of the long side is 34 mm, the length of the short side is 24 mm, the width of the long portion is 3 mm, the thickness of the long portion is 1 mm, and the outer shape is An absorption polarizer (manufactured by Sumitomo Chemical Co., Ltd., SRW062A) having a rectangular shape with a long side length of 30 mm, a short side length of 20 mm, and a thickness of 110 μm was prepared. At this time, the absorption axis (polarization axis) of the absorptive polarizer was parallel to the long side of the rectangle. An adhesive (Aron Alpha EXTRA 4000, manufactured by Toa Gosei Co., Ltd.) was applied to the support member, and an absorptive polarizer was attached to the support member to produce an optical element of Comparative Example 1. In this optical element, as shown in FIG. 8, the outer periphery of the absorptive polarizer is entirely the fixed region 1 a. That is, in the optical element of Comparative Example 1, there is no non-fixed region between the support member 1 and the polarizer 2.

  The optical element of Examples 1 to 5 and the optical element of Comparative Example 1 manufactured as described above were evaluated for deflection and luminance unevenness. The results are shown in Table 1 below. The evaluation of deflection and the evaluation of luminance unevenness were performed as follows.

(Evaluation of deflection)
After heating the optical elements of Examples 1 to 5 and Comparative Example 1 at 80 ° C. for 1 day, the deflection state of the polarizer was visually observed according to the following criteria.
○: Deflection state is not observed △: Deflection state is slightly observed ×: Deflection part is observed

(Evaluation of uneven brightness)
The optical elements of Examples 1 to 5 and Comparative Example 1 were mounted on a projection-type image display device (Japan Avionics Co., Ltd., iP-55) before heating and after heating at 80 ° C. for 1 day. The brightness of the displayed image was measured with a spectral radiance meter CS-2000 manufactured by Konica Minolta. The projection display apparatus was set to display an image so that a square white screen with a side of 2 m was displayed on the screen. The screen was installed in front of the projector at a point 2 m away. With the said luminance meter, the brightness | luminance in the front (measurement location 1) of the said projection type video display apparatus and the location (measurement location 2) moved 80 cm to the horizontal direction from the front was measured. At this time, the luminance meter was installed so that the angle formed by the straight line connecting the projection image display device and the measurement location on the front of the screen and the straight line connecting the luminance meter and each measurement location on the screen was 15 degrees. The obtained luminance value was applied to the following formula, and the rate of change in luminance before and after heating was determined. In addition, the value below the first decimal place was rounded off.
Rate of change = {(luminance value after heating / luminance value before heating) −1} × 100 (%)

  As can be seen from Table 1, with respect to the optical elements of Examples 1 to 5, there was almost no deflection and the luminance unevenness was very small. This is because the both ends of the polarizer in the stretching direction of the polarizer are fixed to the support member, and at least a part other than the both ends is not fixed to the support member. Even if heat is applied to the film to cause contraction in the stretching direction, it is considered that the contraction is suppressed due to the tension generated by fixing the support member. On the other hand, in the optical element of Comparative Example 1, a bent portion was observed and the luminance unevenness was large. This is considered because the entire outer periphery of the polarizer is fixed by the support member, so that deformation due to thermal expansion could not be effectively released at the end in the direction orthogonal to the stretching direction of the polarizer. It is done.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. Further, in the above-described embodiment, the size, shape, material, quantity, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within a range in which the effect of the present invention is exhibited. is there. In addition, the present invention can be appropriately modified and implemented without departing from the scope of the object of the present invention.

  The optical element of the present invention is suitably used in an optical device in which polarized light is useful, such as a liquid crystal projector.

DESCRIPTION OF SYMBOLS 1 Support member 1a Fixed area | region 1b, 1b 'Long part 1c Opening 2 Polarizer 2a End part

Claims (8)

  An optical element having a polarizer having a polarization axis in a specific direction and a support member that supports an outer peripheral portion of the polarizer, wherein both ends of the polarizer in the polarization axis direction of the polarizer are the support members The optical element is fixed to the support member, and at least a part other than the both end portions is not fixed to the support member.   The optical element according to claim 1, wherein the polarizer is an absorptive polarizer, and the polarization axis direction is an absorption axis direction of the absorptive polarizer.   3. The optical according to claim 1, wherein the polarizer has a line-symmetric shape having a symmetry axis in a direction orthogonal to the polarization axis direction or in a direction parallel to the polarization axis direction. element.   The fixed region of the support member of the polarizer at the both end portions is provided at a position that is orthogonal to the polarization axis direction and symmetrical with respect to an imaginary line passing through the center of the polarizer. The optical element according to claim 1.   The support member is composed of a frame body in which four long portions are connected in a quadrangular shape so as to form an opening in the center, and both end portions of the polarizer are formed of the long portions of the support member. The optical element according to claim 1, wherein the optical element is fixed to the support member along a direction orthogonal to the longitudinal direction.   The optical element according to claim 1, wherein the polarizer has a thickness of 10 μm or more and 500 μm or less.   The optical element according to claim 1, wherein the support member is made of metal.   The light source, a display element disposed on an optical path of light emitted from the light source, and the light incident side and / or the emission side of the display element according to any one of claims 1 to 7. A projection-type image display device.

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