JP2010134287A - Polarized beam splitter and liquid crystal projector using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarized beam splitter provided with a functional layer for removing incident ultraviolet light component or ultraviolet light component and infrared light component and a liquid crystal projector using the same. <P>SOLUTION: The polarized beam splitter 101 includes a first prism member 10, a second prism member 20, a polarization separation film 30, a cold mirror 40, a light shielding plate 50, a retardation layer 60 and a functional layer 70. The functional layer 70 is arranged on a light incident surface of the second prism member 20 and has a function for removing ultraviolet light component of the incident light or ultra violet component or infrared light component and the functional layer 70 is, for example, a coating layer applied on the light incident surface of the second prism member 20 and is an UV cut film or an UVIR cut film laminated on the light incident surface of the second prism member 20. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a polarization beam splitter (PBS) having a function of removing an ultraviolet light component or ultraviolet light component and infrared light component of incident light, and a liquid crystal projector using the same.

  As shown in FIG. 11, the liquid crystal projector includes a light source and an optical system including a plurality of optical components including a polarization beam splitter, a liquid crystal panel, and a projection lens, and guides light from the light source to the optical system to display an image. The light is projected from the projection lens as light.

  Conventionally, as shown in FIG. 12, a polarizing beam splitter W used in a device such as a liquid crystal projector alternately joins a plurality of first prism members 1 and second prism members 2 having a parallelogram cross section. Thus, a flat splitter main body is formed. A polarized light separation film 3 and a cold mirror are alternately applied to the joint surface between the first prism member 1 and the second prism member 2 by performing a polarization separation function process and a mirror surface process for separating incident light into S-polarized light and P-polarized light. 4 is formed.

  In the splitter body, a light shielding plate 5 is disposed on the light incident surface of the first prism member 1, and a resin such as polycarbonate (PC) is disposed on a surface (light emitting surface) facing the light incident surface of the first prism member 1. The retardation layer (retardation film) 6 is disposed.

  As indicated by an arrow in FIG. 12, the light incident on the second prism member 2 transmits P-polarized light and reflects S-polarized light through the polarization separation film 3 formed by the polarization separation function process. Separated into polarized light and p-polarized light. The transmitted light passes through the phase difference layer 6 and is emitted forward, while the reflected light is further reflected by the cold mirror 4 formed by mirror processing and emitted forward.

  In a liquid crystal projector, heat is generated from an optical system and an electronic component composed of a plurality of optical components including a light source, a polarizing beam splitter, a liquid crystal panel, and a projection lens, and the light from the light source includes an ultraviolet component and an infrared ray. There are light components, and these ultraviolet light components and the like can change the phase difference layer 6 of the polarization beam splitter W (discoloration, phase difference reduction). In particular, the retardation layer 6 of the polarizing beam splitter W is generally formed of a resin film, such as polycarbonate (PC), and has a defect of low UV resistance, so that the retardation layer 6 can be prevented from being deteriorated. It is necessary to remove the ultraviolet light component and the infrared light component of the light from the light source. Therefore, as shown in FIG. 11, in a liquid crystal projector, a method of cutting an ultraviolet light by providing a UV filter F for removing an ultraviolet light component between a light source and a polarizing beam splitter is generally used. Yes.

  In a liquid crystal projector, a UV filter for removing ultraviolet light components and an IR filter for removing infrared light components are arranged between a light source and a polarizing beam splitter, or an ultraviolet light component and an infrared light component. A method of arranging a UVIR filter that simultaneously removes UV light and cutting ultraviolet light and infrared light is used (see, for example, Patent Document 1 and Patent Document 2).

  In the case of the projector described in Patent Document 1, a collimating lens and a wavelength tunable filter are provided between the light source and the polarizing beam splitter, and a UV filter and an IR filter are provided between the collimating lens and the wavelength tunable filter. ing. In the case of the projection apparatus described in Patent Document 2, a reflector, a first lens array, a second lens array, a condenser lens, and the like are arranged between the light source and the polarization beam splitter in order from the light source side. Furthermore, a UVIR filter is provided between the reflector and the first lens array.

Japanese Patent Application Laid-Open No. 11-14492 JP-A-7-287224

  However, the above-described conventional liquid crystal projector, and the projector and the projection device disclosed in Patent Document 1 and Patent Document 2 cannot completely cut the ultraviolet light component of the light from the light source, and the UV filter or the UVIR filter. Since the leakage of ultraviolet light from the surroundings of the liquid crystal is also possible, the ultraviolet light component that has passed through and the ultraviolet light component that has leaked from around the polarizing beam splitter altered the retardation layer (discoloration, decreased phase difference) and displayed. There was a problem of lowering the image quality.

As a result of illuminance measurement immediately before the incidence of the polarizing beam splitter using a commercially available projector, visible light (550 nm) is 20 W / cm ² and ultraviolet light (350 nm) is 4 mW / cm ² . This ultraviolet light of 4 mW / cm ² can be sufficiently deteriorated (discolored) with respect to a retardation layer, particularly a retardation layer made of polycarbonate (PC).

  In addition, when the retardation layer begins to change color (yellowing), absorption in the visible light region increases, heat is generated, the retardation layer is overheated, burnt, and burnt, and not only the projected image quality deteriorates. There is also a fire hazard.

  On the other hand, there is a crystal as a retardation layer having strong light resistance, but there is a drawback that it is expensive and difficult to process.

  Furthermore, in recent years, liquid crystal projectors have increased in brightness, high image quality, and increased screen size, and a brighter projection state is desired. Therefore, it is necessary to increase the brightness of the light source. There is a demand for polarizing beamsplitters with strong ultraviolet rays.

  Therefore, the present invention provides a functional layer for removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component on the light incident surface of the polarizing beam splitter, or the optical path from the light incident surface to the retardation layer. Arrangement suppresses discoloration (yellowing) of the retardation layer due to ultraviolet light component and infrared light component, prevents charring due to discoloration, deviation of phase difference value, etc. An object of the present invention is to provide a polarizing beam splitter that can be prevented and a liquid crystal projector using the same.

  In order to solve the above-described problems, a polarizing beam splitter according to the present invention is configured by alternately joining a first prism member into which light from a light source is not introduced and a second prism member into which light from the light source is introduced. And a splitter body in which polarization separation function processing for separating incident light into S-polarized light and P-polarized light and mirror surface processing are alternately performed on a joint surface between the first prism member and the second prism member; A phase difference layer disposed on the light exit surface of the first prism member and a light incident surface of the second prism member, or an optical path from the light incident surface to the phase difference layer, and incident light. And a functional layer that removes ultraviolet light components and infrared light components.

  For example, the functional layer is disposed between the light emitting surface of the first prism member and the retardation layer.

  Further, for example, the functional layer is disposed on the first prism member side or the second prism member side of the polarization separation film formed by the polarization separation function process.

  Further, for example, the functional layer is made of a resin film in which an ultraviolet cut agent that reflects or absorbs at least ultraviolet light is blended.

  Further, for example, the functional layer is formed by adding an ultraviolet cut agent that reflects or absorbs at least ultraviolet light to an adhesive for attaching the retardation layer.

  The polarizing beam splitter according to the present invention is configured by alternately joining the first prism member into which light from the light source is not introduced and the second prism member into which light from the light source is introduced, and the first prism member. A splitter body in which polarization separation function processing for separating incident light into S-polarized light and P-polarized light and mirror surface processing are alternately performed on a joint surface between one prism member and the second prism member; and the first prism And a retardation layer disposed on the light exit surface of the member, wherein the retardation layer has a function of removing an ultraviolet light component or an ultraviolet light component and an infrared light component of incident light.

  For example, the retardation layer is formed of a resin material containing at least an ultraviolet cut agent that reflects or absorbs ultraviolet light.

  Also, for example, the retardation layer is made of at least one liquid crystalline polymer material that contains at least an ultraviolet cut agent that reflects or absorbs ultraviolet light.

  In order to solve the above-described problems, a liquid crystal projector according to the present invention includes a light source and an optical system including a plurality of optical components including a polarization beam splitter, a liquid crystal panel, and a projection lens, and transmits light from the light source. A liquid crystal projector for guiding to an optical system and projecting as image light from the projection lens, wherein the polarization beam splitter includes a first prism member into which light from a light source is not introduced and a second light into which light from the light source is introduced. Polarization separation function processing and mirror surface processing that are configured by alternately joining prism members, and that separate incident light into S-polarized light and P-polarized light on a joint surface between the first prism member and the second prism member. Are alternately provided, a retardation layer disposed on a light emitting surface of the first prism member, a light incident surface of the second prism member, Is disposed on the optical path from the light incident surface to the retardation layer, characterized in that it comprises a functional layer that removes ultraviolet light component of the incident light or ultraviolet light component, and an infrared light component.

  In order to solve the above problems, a liquid crystal projector according to the present invention includes a light source and an optical system including a plurality of optical components including a polarization beam splitter, a liquid crystal panel, and a projection lens, and the light from the light source. The polarizing beam splitter is a first prism member into which light from a light source is not introduced and light from the light source is introduced into the polarizing projector. A polarization separation function process and a mirror surface, which are configured by alternately joining two prism members and separating incident light into S-polarized light and P-polarized light on a joint surface between the first prism member and the second prism member. A splitter body that is alternately processed, and a retardation layer disposed on the light exit surface of the first prism member, wherein the retardation layer is a purple layer of incident light. And having a function of removing a light component or ultraviolet light component, and an infrared light component.

  According to the polarizing beam splitter of the present invention, the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light on the light incident surface of the second prism member or on the optical path from the light incident surface to the retardation layer. By disposing a functional layer that removes light components, the discoloration (yellowing) of the retardation layer due to ultraviolet and infrared rays is suppressed, and the occurrence of scorching due to the discoloration, deviation of the retardation value, etc. is prevented. Can be made highly durable.

  Further, according to the polarizing beam splitter of the present invention, the retardation layer has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component, so that the light resistance of the retardation layer is increased. The polarization beam splitter can be made highly durable by preventing discoloration (yellowing) of the retardation layer due to ultraviolet rays and infrared rays, and preventing the occurrence of scorching due to the discoloration and the deviation of the retardation value. .

  In addition, the functional layer is disposed on the first prism member side or the second prism member side of the polarization separation film formed by the polarization separation function process, so that the retardation layer by ultraviolet rays and infrared rays is formed. While suppressing discoloration (yellowing), a thinner polarizing beam splitter can be obtained.

  According to the liquid crystal projector of the present invention, the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component are incident on the light incident surface of the polarization beam splitter or on the optical path from the light incident surface to the retardation layer. By disposing the functional layer to be removed, the light resistance of the retardation layer is improved, discoloration (yellowing) of the retardation layer by ultraviolet rays and infrared rays is suppressed, and the occurrence of charring due to discoloration, deviation of retardation value, etc. It is possible to prevent deterioration of projected image quality and the like. Therefore, it is possible to increase the brightness of the light source (lamp) of the liquid crystal projector, and it is possible to provide a brighter and larger screen liquid crystal projector.

  Hereinafter, a polarizing beam splitter according to an embodiment of the present invention and a liquid crystal projector using the same will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing a configuration of a polarizing beam splitter 101 as the first embodiment. In FIG. 1, a part of the cross section of the polarization beam splitter 101 is shown.

  As shown in FIG. 1, the polarization beam splitter 101 includes a first prism member 10, a second prism member 20, a polarization separation film (PBS film) 30, a cold mirror 40, a light shielding plate 50, and a position. The phase difference layer 60 and the functional layer 70 are included.

  The configuration of the polarization beam splitter 101 is not limited to using the light shielding plate 50. Other light shielding means may be used.

  The first prism member 10 and the second prism member 20 have a cross section formed in a parallelogram. In the case of a polarizing beam splitter for a liquid crystal projector, glass having a low photoelastic constant is used to avoid the influence of heat.

  The first prism member 10 to which light from the light source is not introduced and the second prism member 20 to which light from the light source is introduced are alternately joined, and incident light is separated into S-polarized light and P-polarized light on the joint surface. The splitter main body N in which the polarized light separation function processing and the mirror surface processing are alternately performed is configured.

  The polarization separation film 30 is formed by performing a polarization separation function process for separating incident light into S-polarized light and P-polarized light on the joint surface between the first prism member and the second prism member. The polarization separation film 30 separates S-polarized light and P-polarized light by transmitting incident light through P-polarized light and reflecting S-polarized light.

  The cold mirror 40 is formed by performing a mirror surface treatment on the joint surface between the first prism member and the second prism member. The cold mirror 40 reflects the S-polarized light separated by the polarization separation film and emits it forward.

  The light shielding plate 50 is disposed on the light incident surface of the first prism member and blocks incident light.

  The retardation layer 60 is disposed on a surface (that is, a light emitting surface) facing the light incident surface of the first prism member, and has at least one polycarbonate film. The retardation layer 60 may be made of at least one layer of a polymer material having liquid crystallinity.

  The functional layer 70 is disposed on the light incident surface of the second prism member 20 and has a function of removing the ultraviolet light component or the ultraviolet light component and the infrared light component of the incident light. For example, the functional layer 70 is a coating layer having a function of removing an ultraviolet light component or an ultraviolet light component and an infrared light component applied to the light incident surface of the second prism member 20, or the second layer. It is a UV cut film or a UVIR cut film having a function of removing an ultraviolet light component, an ultraviolet light component and an infrared light component attached to the light incident surface of the prism member 20.

  FIG. 2 shows the result of light irradiation evaluation with and without the functional layer 70 when the retardation layer 60 is a polycarbonate film.

As a test method, a UV cut with a half-value of 430 nm (wavelength at which the transmittance is 50%) is applied to a glass provided with a retardation layer (retardation film) designed in the vicinity of retardation value = λ / 2. Light irradiation is performed with or without the film (functional layer 70). As the irradiation lamp, a UV fluorescent lamp having an illuminance at 350 nm of 3 mW / cm ² was used.

  Evaluation method: The relationship between the UV irradiation time of the retardation layer 60 at the wavelength λ = 440 nm and the polarization rotation transmittance (%) was measured. When there was a UV cut film, the measurement was carried out with the UV cut film removed. The measurement results are shown in FIG.

  As shown in FIG. 2, when the UV cut film is present (with the UV cut function), the polarization rotation transmittance is not substantially changed. On the other hand, when the UV cut film is not present (without the UV cut function), the polarization rotation transmittance is not changed. Was found to decrease with irradiation time.

  FIG. 3 shows the results of light irradiation evaluation with and without the functional layer 70 when the retardation layer 60 is made of a liquid crystalline polymer. The test method and the evaluation method are the same as in the case of FIG. 2 described above.

  As shown in FIG. 3, in the retardation layer 60 made of a liquid crystalline polymer, when the UV cut film is present (with the UV cut function), the polarization rotation transmittance is not substantially changed, while the UV cut film is not present (UV In the case of no cutting function), it was found that the polarization rotation transmittance greatly decreased with the irradiation time.

  Thus, in the present embodiment, the polarization beam splitter 101 includes the first prism member 10, the second prism member 20, the polarization separation film 30, the cold mirror 40, the light shielding plate 50, and the phase difference. The layer 60 is composed of a functional layer 70. The functional layer 70 is disposed on the light incident surface of the second prism member 20 and has a function of removing the ultraviolet light component or the ultraviolet light component and the infrared light component of the incident light.

  As a result, the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component can be removed, the discoloration (yellowing) of the retardation layer due to the ultraviolet light and the infrared light is suppressed, and the charring due to the discoloration, the retardation value Therefore, the polarization beam splitter can be made highly durable, and it is possible to prevent deterioration of image quality projected when applied to a liquid crystal projector or the like.

  FIG. 4 is a cross-sectional view showing the configuration of the polarization beam splitter 102 as the second embodiment. In FIG. 4, a part of the cross section of the polarization beam splitter 102 is shown.

  As shown in FIG. 4, the polarization beam splitter 102 includes a first prism member 10, a second prism member 20, a polarization separation film (PBS film) 30, a cold mirror 40, a light shielding plate 50, and a position. It is comprised from the phase difference layer 60 and the functional layer 70A.

  In the polarization beam splitter 102 as the second embodiment, the first prism member 10, the second prism member 20, the polarization separation film (PBS film) 30, the cold mirror 40, and the light shielding plate 50 are provided. The configuration with the retardation layer 60 is the same as that of the first embodiment.

  The functional layer 70 </ b> A is disposed on the optical path from the light incident surface of the second prism member 20 to the retardation layer 60, that is, between the polarization separation film 30 and the first prism member 10. The functional layer 70A has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component.

  For example, the functional layer 70A is a coating layer having a function of removing an ultraviolet light component applied between the polarization separation film 30 and the first prism member 10, or an ultraviolet light component and an infrared light component, Alternatively, it is a UV cut film or a UVIR cut film having a function of removing an ultraviolet light component, an ultraviolet light component and an infrared light component attached between the polarization separation film 30 and the first prism member 10.

  In this case, the ultraviolet light component or the ultraviolet light component and the infrared light component of the light that has passed through the polarization separation film 30 can be removed.

  Thus, in the present embodiment, the polarization beam splitter 102 includes the first prism member 10, the second prism member 20, the polarization separation film 30, the cold mirror 40, the light shielding plate 50, and the phase difference. It is composed of a layer 60 and a functional layer 70A. The functional layer 70 </ b> A is disposed between the polarization separation film 30 and the first prism member 10, and has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component.

  Thereby, the ultraviolet light component or the ultraviolet light component and the infrared light component of the light that has passed through the polarization separation film 30 can be removed, the discoloration (yellowing) of the retardation layer due to the ultraviolet light and the infrared light is suppressed, and the color change. Can prevent the occurrence of charring, phase difference deviation, etc., and can improve the durability of the polarizing beam splitter, and can prevent the deterioration of the projected image quality when applied to a liquid crystal projector or the like. .

  FIG. 5 is a cross-sectional view showing the configuration of the polarization beam splitter 103 as the third embodiment. In FIG. 5, a part of the cross section of the polarization beam splitter 103 is shown.

  As shown in FIG. 5, the polarization beam splitter 103 includes a first prism member 10, a second prism member 20, a polarization separation film (PBS film) 30, a cold mirror 40, a light shielding plate 50, and a position. It is comprised from the phase difference layer 60 and the functional layer 70B.

  In the polarization beam splitter 103 as the third embodiment, the first prism member 10, the second prism member 20, the polarization separation film (PBS film) 30, the cold mirror 40, and the light shielding plate 50 are provided. The configuration with the retardation layer 60 is the same as that of the first embodiment.

  The functional layer 70 </ b> B is disposed on the optical path from the light incident surface of the second prism member 20 to the retardation layer 60, that is, between the polarization separation film 30 and the second prism member 20. The functional layer 70B has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component.

  For example, the functional layer 70B is a coating layer having a function of removing an ultraviolet light component or an ultraviolet light component and an infrared light component applied between the polarization separation film 30 and the second prism member 20, Alternatively, it is a UV cut film or a UVIR cut film having a function of removing an ultraviolet light component, an ultraviolet light component and an infrared light component attached between the polarization separation film 30 and the second prism member 20.

  In this case, the ultraviolet light component or the ultraviolet light component and the infrared light component of the light reflected from the polarization separation film 30 and the light that has passed through the polarization separation film 30 can be removed.

  As described above, in the present embodiment, the polarization beam splitter 103 includes the first prism member 10, the second prism member 20, the polarization separation film 30, the cold mirror 40, the light shielding plate 50, and the phase difference. It is composed of a layer 60 and a functional layer 70B. The functional layer 70B is disposed between the polarization separation film 30 and the second prism member 20, and has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component.

  Thereby, the ultraviolet light component of the light reflected from the polarization separation film 30 and the light that has passed through the polarization separation film 30, or the ultraviolet light component and the infrared light component can be removed, and the retardation layer by ultraviolet light and infrared light. This prevents the discoloration (yellowing) of the image, prevents the occurrence of charring due to the discoloration, the shift of the phase difference value, etc., and makes the polarizing beam splitter highly durable. It is possible to prevent deterioration of the material.

  FIG. 6 is a cross-sectional view showing the configuration of the polarization beam splitter 104 as the fourth embodiment. In FIG. 6, a part of the cross section of the polarization beam splitter 104 is shown.

  As shown in FIG. 6, the polarization beam splitter 104 includes a first prism member 10, a second prism member 20, a polarization separation film (PBS film) 30, a cold mirror 40, a light shielding plate 50, and a position. It is comprised from the phase difference layer 60 and the functional layer 70C.

  In the polarization beam splitter 104 as the fourth embodiment, the first prism member 10, the second prism member 20, the polarization separation film (PBS film) 30, the cold mirror 40, and the light shielding plate 50 are provided. The configuration with the retardation layer 60 is the same as that of the first embodiment.

  The functional layer 70 </ b> C is disposed on the optical path from the light incident surface of the second prism member 20 to the retardation layer 60, that is, between the light emitting surface of the first prism member 10 and the retardation layer 60. . The functional layer 70 </ b> C has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component.

  For example, the functional layer 70 </ b> C is a coating having a function of removing an ultraviolet light component applied between the light emitting surface of the first prism member 10 and the retardation layer 60, or an ultraviolet light component and an infrared light component. UV cut film having a function of removing an ultraviolet light component, or an ultraviolet light component and an infrared light component, which is a layer or bonded between the light emitting surface of the first prism member 10 and the retardation layer 60 Or UVIR cut film.

  In this case, the ultraviolet light component or the ultraviolet light component and the infrared light component of the light that has passed through the polarization separation film 30 can be removed.

  As described above, in the present embodiment, the polarization beam splitter 104 includes the first prism member 10, the second prism member 20, the polarization separation film 30, the cold mirror 40, the light shielding plate 50, and the phase difference. The layer 60 is composed of a functional layer 70C. The functional layer 70 </ b> C is disposed between the retardation layer 60 and the first prism member 10 and has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component.

  Thereby, the ultraviolet light component or the ultraviolet light component and the infrared light component of the light that has passed through the polarization separation film 30 can be removed, the discoloration (yellowing) of the retardation layer due to the ultraviolet light and the infrared light is suppressed, and the color change. Can prevent the occurrence of charring, phase difference deviation, etc., and can improve the durability of the polarizing beam splitter, and can prevent the deterioration of the projected image quality when applied to a liquid crystal projector or the like. .

  FIG. 7 is a cross-sectional view showing a configuration of a polarization beam splitter 105 as a fifth embodiment. In FIG. 7, a part of the cross section of the polarization beam splitter 105 is shown.

  As shown in FIG. 7, the polarization beam splitter 105 includes a first prism member 10, a second prism member 20, a polarization separation film (PBS film) 30, a cold mirror 40, a light shielding plate 50, and a function. And a retardation layer 60 </ b> A as a conductive layer.

  In the polarization beam splitter 105 as the fifth embodiment, the first prism member 10, the second prism member 20, the polarization separation film (PBS film) 30, the cold mirror 40, the light shielding plate 50, and the like. The configuration of is the same as that of the first embodiment.

  In addition to functioning as a phase difference layer, the phase difference layer 60 </ b> A has a function of removing an ultraviolet light component, or an ultraviolet light component and an infrared light component of light that has passed through the polarization separation film 30.

  The phase difference layer 60A is formed of, for example, a resin material blended with at least an ultraviolet cut agent that reflects or absorbs ultraviolet light, or has at least one liquid crystallinity blended with an ultraviolet cut agent that reflects or absorbs at least ultraviolet light. It consists of a polymeric material. In this case, it is desirable that the addition amount of the UV-cutting agent is such that it can cut ultraviolet light and does not affect the optical characteristics.

  In this case, the ultraviolet light component or the ultraviolet light component and the infrared light component of the light that has passed through the polarization separation film 30 can be removed.

  As described above, in the present embodiment, the polarization beam splitter 105 includes the first prism member 10, the second prism member 20, the polarization separation film 30, the cold mirror 40, the light shielding plate 50, and the phase difference. And 60A. In addition to functioning as a phase difference layer, the phase difference layer 60 </ b> A has a function of removing an ultraviolet light component, or an ultraviolet light component and an infrared light component of light that has passed through the polarization separation film 30.

  As a result, the retardation layer has a function of removing the ultraviolet light component of the incident light, or the ultraviolet light component and the infrared light component, thereby improving the light resistance of the retardation layer, and the level of the ultraviolet light and infrared light. Suppresses discoloration (yellowing) of the phase difference layer, prevents charring due to discoloration, prevents phase difference deviations, etc., and makes the polarizing beam splitter highly durable. It is possible to prevent degradation of image quality.

  FIG. 8 is a cross-sectional view showing a configuration of a polarization beam splitter 106 as the sixth embodiment. In FIG. 8, a schematic cross section in the length direction of the retardation layer 60B of the polarization beam splitter 106 is shown.

  As shown in FIG. 8, the polarizing beam splitter 106 is provided with a retardation layer 60 </ b> B made of two liquid crystalline polymers on the light exit surface of the splitter body N (that is, the light exit surface of the first prism member 10). In addition, a UV-cutting agent that reflects or absorbs ultraviolet light was added to the liquid crystalline polymer layer of the retardation layer 60B. Further, the functional layer 70 </ b> D is disposed on the light incident surface of the splitter body N (that is, the light incident surface of the second prism member 20). In this case, it is desirable that the addition amount of the UV-cutting agent is such that it can cut ultraviolet light and does not affect the optical characteristics.

  The retardation layer 60B has a two-layer polymer material having liquid crystallinity. For example, the first alignment film 62B formed on the glass substrate 61B, the first polymer material layer 63B stacked on the first alignment film 62B, and the first polymer material layer 63B are stacked. The second alignment film 64B and a second polymer material layer 65B stacked on the second alignment film 64B are configured. Here, the first polymer material layer 63B and the second polymer material layer 65B are formed by adding a predetermined amount of UV-cutting agent to the liquid crystalline polymer material. The retardation layer 60B is bonded to the first prism member 10 with an adhesive 66B.

  The polymer material having liquid crystallinity is also referred to as a liquid crystalline polymer (LCP). In general, it is a polymer material that exhibits liquid crystallinity in a molten state (a state where the molecules are arranged between regularly arranged crystals and a randomly arranged liquid), and has good fluidity during molding. It is suitable as a material for precision molded products with excellent strength, and it has considerably high heat resistance as a plastic.

  Here, the first alignment film 62B and the second alignment film 64B are films for aligning a polymer material having liquid crystallinity. In this example, a polyamic acid type alignment film material is used. The thickness (film thickness) of the first alignment film 62B and the second alignment film 64B is preferably in the range of 300 to 1000 mm. In this example, the thickness of the first alignment film 62B and the second alignment film 64B is 700 mm.

  The functional layer 70 </ b> D is an optical multilayer film that is formed by a film forming method such as sputtering or vacuum vapor deposition, and has a function of removing ultraviolet components of light, or ultraviolet components and infrared components.

  In this case, the ultraviolet light component of the light or the ultraviolet light component and the infrared light component can be removed by the retardation layer 60B and the functional layer 70D.

  As described above, in this embodiment, the polarization beam splitter 106 adds a predetermined amount of the UV-cutting agent to the liquid crystalline polymer layer of the retardation layer 60B, and further, on the light incident surface of the second prism member 20. By disposing the functional layer 70D, the ultraviolet light component of the light that has passed through the functional layer 70D, or the ultraviolet light component and the infrared light component can be removed by the retardation layer 60B. More effective suppression of layer discoloration (yellowing), prevention of charring due to discoloration, deviation of phase difference value, etc., and high durability of the polarizing beam splitter, and application to liquid crystal projectors, etc. It is possible to prevent deterioration of image quality projected at the time.

  FIG. 9 is a cross-sectional view showing the configuration of the polarization beam splitter 107 as the seventh embodiment. FIG. 9 shows an outline of a cross section in the length direction of the retardation layer 60 </ b> C of the polarization beam splitter 107.

  As shown in FIG. 9, the polarizing beam splitter 107 is provided with a retardation layer 60 </ b> C made of a two-layer polycarbonate film on the light exit surface of the splitter body N (that is, the light exit surface of the first prism member 10). A functional layer 70E to which a predetermined amount of UV-cutting agent is added is disposed between the retardation layer 60C and the light emitting surface of the first prism member 10. Further, the functional layer 70 </ b> D is disposed on the light incident surface of the splitter body N (that is, the light incident surface of the second prism member 20).

  The functional layer 70E is, for example, a TAC film (Tri Acetyl Cellulose) manufactured by Fuji Film or Konica Minolta. This TAC film is disposed on the first prism member 10 via an adhesive 61C. Moreover, the 1st polycarbonate film 63C and the 2nd polycarbonate film 65C are arrange | positioned through the adhesive agents 62C and 64C on the TAC film.

  The functional layer 70 </ b> D is an optical multilayer film that is formed by a film forming method such as sputtering or vacuum vapor deposition, and has a function of removing ultraviolet components of light, or ultraviolet components and infrared components.

  In this case, the ultraviolet light component of the light, or the ultraviolet light component and the infrared light component can be removed by the retardation layer 60C and the functional layer 70D.

  As described above, in the present embodiment, the polarizing beam splitter 107 arranges the TAC film 70E to which a predetermined amount of the UV cut agent is added between the retardation layer 60C and the light exit surface of the first prism member 10. Further, by disposing the functional layer 70D on the light incident surface of the second prism member 20, the phase difference between the ultraviolet light component or the ultraviolet light component and the infrared light component of the light that has passed through the functional layer 70D. It can be removed by the layer 60C, and the discoloration (yellowing) of the retardation layer due to ultraviolet rays and infrared rays is more effectively suppressed, and the occurrence of scorching due to the discoloration, deviation of the retardation value, etc. is prevented. High durability can be achieved, and deterioration of image quality projected when applied to a liquid crystal projector or the like can be prevented.

  Hereinafter, a liquid crystal projector using the polarizing beam splitter according to the present invention will be described. FIG. 10 is a diagram showing a configuration of an optical system of the liquid crystal projector 100 using the polarizing beam splitter 101 of the present invention.

  As shown in FIG. 10, the liquid crystal projector 100 includes a light source lamp 111, integrators (lens arrays) 112 and 113 that make the light beam emitted from the light source lamp 1 parallel to the traveling direction of the light beam, and the incident light beam having different polarization components. Polarizing beam splitter (PBS) 101 that separates into two light beams, superimposing lens 114, R reflecting dichroic mirror 115, reflecting mirror 116, R field lens 117, R liquid crystal panel 118, cross dichroic prism 119, G reflecting dichroic mirror 120, A G field lens 121, a G liquid crystal panel 122, a relay optical system (relay lenses 123, 125, 127, reflection mirrors 124, 126), a B liquid crystal panel 128, and a projection lens 129 are provided.

  Since the liquid crystal projector 100 has the same configuration as the conventional one other than the polarizing beam splitter (PBS) 101, detailed description of the operation of the liquid crystal projector 100 is omitted here.

  As described above, in the present embodiment, the liquid crystal projector 100 uses the polarization beam splitter 101 to remove the ultraviolet light component or the ultraviolet light component and the infrared light component of the incident light incident on the polarization beam splitter 101. In addition, it is possible to suppress discoloration (yellowing) of the retardation layer due to ultraviolet rays and infrared rays, and to prevent the occurrence of charring due to the discoloration, the shift of the retardation value, and the like, and the deterioration of the projected image quality and the like can be prevented. Therefore, it is possible to increase the brightness of the light source (lamp) of the liquid crystal projector, and it is possible to provide a brighter and larger screen liquid crystal projector.

  In the above-described embodiment, the case where the UV light blocking agent is blended with the retardation layer 60A of the polarization beam splitter 105 has been described. However, the present invention is not limited to this. For example, you may mix | blend a ultraviolet-ray cutting agent with the adhesive agent which adhere | attaches a phase difference layer.

  Moreover, it is not limited to single use of the 1st-7th embodiment mentioned above. By using the first to seventh embodiments in combination, the UV cut function can be further improved.

  In the above embodiment, the liquid crystal projector 100 uses the polarization beam splitter (PBS) 101. However, the present invention is not limited to this. For example, 102, 103, 104, 105, 106, 107 may be used.

  In the above-described embodiment, the liquid crystal projector is described as an application example of the polarization beam splitters 101, 102, 103, 104, 105, 106, and 107. However, the present invention is not limited to this. You may utilize for another optical instrument.

  The present invention can be used for the purpose of preventing deterioration of a polarizing beam splitter (PBS) used in an optical apparatus such as a liquid crystal projector due to ultraviolet rays and the like, and improving light resistance, heat resistance, and optical performance.

It is sectional drawing which shows the structure of the polarization beam splitter 101 as 1st Embodiment. When the phase difference layer 60 is a polycarbonate film, it is a figure which shows the light irradiation evaluation result in the presence or absence of the functional layer 70. FIG. It is a figure which shows the light irradiation evaluation result in the presence or absence of the functional layer 70, when the phase difference layer 60 uses what consists of a liquid crystalline polymer. It is sectional drawing which shows the structure of the polarization beam splitter 102 as 2nd Embodiment. It is sectional drawing which shows the structure of the polarization beam splitter 103 as 3rd Embodiment. It is sectional drawing which shows the structure of the polarization beam splitter 104 as 4th Embodiment. It is sectional drawing which shows the structure of the polarizing beam splitter 105 as 5th Embodiment. It is sectional drawing which shows the structure of the polarization beam splitter 106 as 6th Embodiment. It is sectional drawing which shows the structure of the polarization beam splitter 107 as 7th Embodiment. It is a figure which shows the structure of the optical system of the liquid crystal projector 100 using the polarizing beam splitter 101 of this invention. It is a figure which shows the structure of the optical system of the conventional liquid crystal projector 1A. It is a figure which shows the structure of the conventional polarizing beam splitter.

Explanation of symbols

1,10 First prism member 2,20 Second prism member 3,30 Polarized light separation film (PBS film)
4, 40 Cold mirror 5, 50 Light shielding plate 6, 60, 60A, 60B, 60C Phase difference layer 61B Glass substrate 61C, 62C, 64C Adhesive 62B First alignment film 63B First polymer material layer 63C First Polycarbonate film 64B second alignment film 65B second polymer material layer 65C second polycarbonate film 66B adhesive 70, 70A, 70B, 70C, 70D, 70E functional layer 100 liquid crystal projector 101, 102, 103, 104, 105, 106, 107 Polarizing beam splitter F UV filter N Polarizing beam splitter body W Polarizing beam splitter

Claims (10)

The first prism member to which light from the light source is not introduced and the second prism member to which light from the light source is introduced are alternately joined, and the first prism member and the second prism member A splitter body in which incident light is separated into S-polarized light and P-polarized light on the joint surface with a polarization separation function process and a mirror surface process alternately;
A retardation layer disposed on a light exit surface of the first prism member;
Functionality that is disposed on the light incident surface of the second prism member or on the optical path from the light incident surface to the retardation layer, and removes the ultraviolet light component or the ultraviolet light component and the infrared light component of the incident light. And a polarization beam splitter.   The polarizing beam splitter according to claim 1, wherein the functional layer is disposed between a light exit surface of the first prism member and the retardation layer.   2. The polarized light according to claim 1, wherein the functional layer is disposed on the first prism member side or the second prism member side of a polarization separation film formed by the polarization separation function process. Beam splitter.   The polarizing beam splitter according to any one of claims 1 to 3, wherein the functional layer is made of a resin film blended with an ultraviolet cut agent that reflects or absorbs at least ultraviolet light.   4. The functional layer according to claim 1, wherein an ultraviolet cut agent that reflects or absorbs at least ultraviolet light is added to an adhesive for attaching the retardation layer. 5. Polarizing beam splitter. The first prism member to which light from the light source is not introduced and the second prism member to which light from the light source is introduced are alternately joined, and the first prism member and the second prism member A splitter body in which incident light is separated into S-polarized light and P-polarized light on the joint surface with a polarization separation function process and a mirror surface process alternately;
A retardation layer disposed on the light exit surface of the first prism member,
The retardation layer has a function of removing an ultraviolet light component of incident light or an ultraviolet light component and an infrared light component.   The polarizing beam splitter according to claim 6, wherein the retardation layer is formed of a resin material containing an ultraviolet cut agent that reflects or absorbs at least ultraviolet light.   7. The polarizing beam splitter according to claim 6, wherein the retardation layer is made of a polymer material having at least one layer of liquid crystal that contains at least an ultraviolet cut agent that reflects or absorbs ultraviolet light. A liquid crystal comprising a light source and an optical system including a plurality of optical components including a polarizing beam splitter, a liquid crystal panel, and a projection lens, and guiding light from the light source to the optical system and projecting it from the projection lens as image light A projector,
The polarizing beam splitter is
The first prism member to which light from the light source is not introduced and the second prism member to which light from the light source is introduced are alternately joined, and the first prism member and the second prism member A splitter body in which incident light is separated into S-polarized light and P-polarized light on the joint surface with a polarization separation function process and a mirror surface process alternately;
A retardation layer disposed on a light exit surface of the first prism member;
Functionality that is disposed on the light incident surface of the second prism member or on the optical path from the light incident surface to the retardation layer, and removes the ultraviolet light component or the ultraviolet light component and the infrared light component of the incident light. And a liquid crystal projector. A liquid crystal comprising a light source and an optical system including a plurality of optical components including a polarizing beam splitter, a liquid crystal panel, and a projection lens, and guiding light from the light source to the optical system and projecting it from the projection lens as image light A projector,
The polarizing beam splitter is
The first prism member to which light from the light source is not introduced and the second prism member to which light from the light source is introduced are alternately joined, and the first prism member and the second prism member A splitter body in which incident light is separated into S-polarized light and P-polarized light on the joint surface with a polarization separation function process and a mirror surface process alternately;
A retardation layer disposed on the light exit surface of the first prism member,
The liquid crystal projector, wherein the retardation layer has a function of removing ultraviolet light components or ultraviolet light components and infrared light components of incident light.

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