JP2005227481A - Optical apparatus and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the deterioration of components and to extend the service life of a product by more effectively blocking UV rays. <P>SOLUTION: Mirrors having UV ray absorbency are used for optical path changing mirrors 10, 11, 12 and 13 being essential components incorporated in a projector, so that the UV rays are absorbed without newly increasing components. The front or rear surface of the mirror is coated with a thin film having UV/IR optical transparency, the UV rays and the IR rays can be removed from the projector optical apparatus. Also, it is possible to apply the mirror to a conventional technology. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical device that exhibits a desired function by illuminating an object using light source light from a light source, and a projector incorporating the optical device.

As a known projector, a projector having an ultraviolet cut filter that cuts off UV light from light source light is known in the apparatus in order to prevent deterioration of components due to UV light (see Patent Document 1).
JP 2002-90505 A

  In the projector, a UV light absorbing device such as an ultraviolet cut filter is inserted substantially vertically on the optical path and absorbs UV light by attenuation when passing through a flat filter. However, if a new filter or the like is specially installed in the projector for UV cut, the weight increases accordingly. Further, the UV absorption amount increases as the distance passing through the UV absorption glass increases. When installed substantially vertically as described above, the thickness of the UV light absorbing device is substantially equal to the passing distance as it is. Therefore, in order to absorb UV light more effectively, it is necessary to increase the passage distance, that is, to make the filter and glass thicker, and the weight increase cannot be ignored.

  Therefore, an object of the present invention is to provide an optical device that can illuminate an object with illumination light from which UV light has been removed more effectively without increasing the weight, and a projector using the optical device.

  For this reason, in the first invention, the optical device guides the light source device that generates light source light including visible light and ultraviolet light, and the light source light from the light source device to the object to be illuminated along the predetermined optical path as illumination light. And an optical system including an optical path conversion member that converts the optical path direction of the illumination light, and the optical path conversion member is formed using UV absorbing glass that absorbs ultraviolet light from the light source light.

  In an optical device, when light source light including visible light and ultraviolet light generated from a light source device is used as illumination light, the ultraviolet light damages various equipment in the optical device. Therefore, removing ultraviolet light in the light source light on a predetermined optical path of the optical device is one of important issues in the use of the optical device. In the present invention, UV absorbing glass is used for an optical path conversion member such as a reflecting mirror or a prism that converts the optical path direction of light using reflection or refraction. Optical path conversion members such as reflection mirrors are usually indispensable parts in an optical device. Therefore, no ultraviolet rays that are harmful from light source light can be used by passing the optical path conversion member without installing new parts for UV cutting. Light can be removed. Therefore, in this optical apparatus, the weight is not increased due to the ultraviolet light removing means. In addition, the conventional optical apparatus can be reduced in weight as compared with a specially provided UV cut filter or the like. Furthermore, for example, when the case where ultraviolet light reciprocates in a glass plate used as a substrate for a deflecting reflecting mirror, which is one of the optical path conversion members, the passing distance of the ultraviolet light is vertical that does not convert the optical path direction. In the incident type glass plate, the light is at least twice as compared with the case where light is transmitted vertically through the glass plate. Actually, the ultraviolet light is obliquely incident on the deflecting reflection mirror, so that the passing distance is further increased. The amount of UV absorption increases as the distance passing through an object having a UV absorption effect increases. Therefore, if UV absorption is performed when the optical path direction is changed by reflection or the like on the optical path conversion member as in the optical device of the present application, more effective ultraviolet light absorption can be achieved.

  In a specific aspect of the present invention, the optical path conversion member is a parallel plate that reflects light source light arranged so as to be inclined with respect to the optical axis, and has a dielectric multilayer film on the front surface, the back surface, or both. In this case, necessary visible light can be obtained as reflected light from the optical path conversion member, and ultraviolet light and infrared light can be attenuated inside the optical path conversion member by selecting the dielectric multilayer film. It is also possible to remove it outside the optical device.

  As one aspect of the optical device, the optical device is formed as the dielectric multilayer film on the surface side on which the light source light is incident, transmits the ultraviolet light, and is further subjected to shading for visible light. Including membrane. In this case, ultraviolet light can be reliably transmitted into the optical path conversion member by the surface-side multilayer film. In addition, by shading, optimal transmission and reflection can always be performed for visible light having different incident angles depending on the incident position with respect to the optical path changing member.

  Furthermore, as an aspect of the optical device, the optical device includes a back side multilayer film that is formed on the back side and transmits ultraviolet light as the dielectric multilayer film. In this case, the ultraviolet light guided into the optical path conversion member passes through the optical path conversion member and is discharged to the back. Thereby, ultraviolet light is removed out of the optical device.

  As another aspect of the optical device, the back-side multilayer film reflects visible light. In this case, the optical path conversion member functions as a reflection mirror or the like, and the visible light is converted in its optical path by reflection on the back surface side multilayer film, so that attenuation of visible light can be relatively reduced.

  Furthermore, as another aspect of the optical device, the optical path conversion member has a metal film that reflects visible light on the back surface side. In this case, the optical path conversion member functions as a reflection mirror or the like, and all the light transmitted through the optical path conversion member is reflected on the back side of the optical path conversion member, so that attenuation of visible light can be reduced. Although ultraviolet light is also reflected, the passing distance of the ultraviolet light inside the optical path conversion member becomes longer.

  As another aspect of the optical device, the surface-side multilayer film is an antireflection film for visible light. In this case, since visible light can be reliably transmitted through the optical path conversion member without loss, attenuation of visible light can be reduced.

  As another aspect of the optical device, the surface-side multilayer film reflects visible light. In this case, the optical path conversion member functions as a reflection mirror or the like, and visible light is reflected without passing through the optical path conversion member, so that attenuation of visible light can be reduced. At this time, since the ultraviolet light passes through the surface-side multilayer film, it is reliably guided into the optical path conversion member, and the ultraviolet light is absorbed and removed by the UV absorbing glass.

  In the second invention, the optical device generates a light source light including visible light and ultraviolet light, and guides the light source light from the light source device as an illumination light to an object to be illuminated along a predetermined optical path. An optical system including an optical path conversion member that converts the optical path direction of the illumination light, and the optical path conversion member is a parallel plate that is arranged to be inclined with respect to the optical axis and reflects the light source light, at least on the back surface side It has a dielectric multilayer film that transmits ultraviolet light and reflects visible light. In this case, ultraviolet light can be removed without using UV absorbing glass.

  Furthermore, as another aspect of the present invention, in the optical device, the dielectric multilayer film transmits infrared light. In this case, in addition to the removal of ultraviolet light, it is possible to remove infrared light.

  A projector according to the present invention includes an optical device having the above characteristics, a light modulation device that is an illumination target illuminated by illumination light from the optical device, and a projection optical system that projects image light that has passed through the light modulation device. Is provided.

  By using an optical device having the above characteristics, the projector can more effectively remove ultraviolet light or the like in illumination light from the light source device while preventing an increase in weight. It is possible to prevent damage and deterioration due to ultraviolet light and the like of the light modulation device and the projection optical system, and extend the life of the equipment.

  In particular, as one aspect of the present invention, in the projector, the optical device includes a light splitting unit that splits the illumination light from the light source device into a plurality of color lights, and the light modulation device individually processes each color light. The optical path conversion member is arranged in the optical path of the blue light divided by the light splitting means. In this case, among the divided illumination lights, blue light usually accompanies a lot of ultraviolet light, so that the optical path changing member is used in the blue light path, so that UV absorption can be performed more effectively.

[First Embodiment]
FIG. 1 is a diagram conceptually illustrating the structure of an image forming unit in a projector according to the present embodiment. The image forming unit 50 includes an illumination device 1 that is an optical device for forming illumination light, a light modulation device 21 that forms a projection image from the illumination light, and a projection that is a projection optical system that projects the formed image. Lens 26.

  The illuminating device 1 includes a light source device 2 that generates a light source light WL including UV light and the like in addition to visible light, a lens array 3 and 4 and a superimposing lens 5 that uniformize the light amount in a light beam cross section, and a light source light WL. Is converted into one type of linearly polarized light, and is then transmitted or reflected selectively according to the wavelength band of light. Dichroic mirrors 14 and 15 for performing color separation of illumination light, relay lenses 16 and 17 for correcting light, and field lenses for adjusting the incident angle of each color light obtained by color separation of illumination light 18, 19, 20. The light source device 2 is composed of a high-pressure mercury lamp or the like, and the light source light WL including UV light and the like in addition to visible light is emitted to the front side. The polarization conversion element array 6 includes a light shielding plate 7, a polarization conversion member 8, and a phase difference plate 9. In addition, about these detailed structures, it shall be based on Unexamined-Japanese-Patent No. 2002-90505 (patent document 1).

  The light modulation device 21 includes liquid crystal light valves 22, 23, and 24 for each color that forms an image from illumination light, and a cross dichroic prism 25 that combines images of each color formed by the illumination light.

  Hereinafter, the function of the main image forming unit will be described in accordance with the procedure of image forming by the main image forming unit. In FIG. 1, a light source device 2 is a device for generating light source light WL to be illumination light for image formation. The light source light WL generated and emitted from the light source device 2 first passes through the lens array 3. Thereafter, the light source light WL is reflected by the mirror 10 and further passes through the lens array 4. Here, the lens arrays 3 and 4 have a function of making the light amount of the light source light WL uniform in the cross section of the light beam. All the light contained in the light source light WL is redirected by being reflected by the mirror 10. The light source light WL is converted into one type of linearly polarized light by passing through the lens array 4 and then passing through the polarization conversion element array 6. Further, a part of the light source light WL is separated as red light RL by the first dichroic mirror 14 from the light made uniform by the superimposing lens 5. Further, the remaining light source light WL is separated into green light GL and blue light BL by the second dichroic mirror 15. The first dichroic mirror 14 has a characteristic of transmitting light of a red light wavelength or less and reflecting other light. Thereby, light in a certain wavelength band passes through the dichroic mirror 14 as red light RL, while other light is reflected by the dichroic mirror 14. Further, the second dichroic mirror 15 has a property of reflecting light having a wavelength equal to or shorter than the green light wavelength and transmitting other light. Thereby, the light reflected by the dichroic mirror 14 in the light source light WL is further separated into the green light GL and the blue light BL. Due to the function of the dichroic mirror described above, the light source light WL is separated into red light RL, green light GL, and blue light BL for each wavelength band.

  The separated red light RL, green light GL, and blue light BL are irradiated to the liquid crystal light valves 22, 23, 24 as illumination light, respectively, thereby forming an image. The red light RL is reflected by the mirror 11 and further guided to the liquid crystal light valve 22 by adjusting the incident angle by the field lens 18 to irradiate the liquid crystal light valve 22. Image light is formed by the liquid crystal light valve 22, and the formed image light is combined with other image light by the cross dichroic prism 25. Similarly, the green light GL is reflected by the dichroic mirror 15, and the incident angle is adjusted by the field lens 19 to be guided to the liquid crystal light valve 23, and image light is formed by the liquid crystal light valve 23. Coupled by the prism 25. The blue light BL is transmitted through the dichroic mirror 15, reflected by the mirrors 12 and 13, and further guided to the liquid crystal light valve 24 by adjusting the incident angle by the field lens 20, and the image light is transmitted by the liquid crystal light valve 24. Formed and coupled by a cross dichroic prism 25. In this case, the optical path of the blue light BL is longer than the optical paths of the other lights. Therefore, it is necessary to correct the beam shape, and the relay lenses 16, 17 and the like are provided in the optical path of blue light for such correction.

  In the cross dichroic prism 25, the images formed by the liquid crystal light valves 22, 23, 24 are combined and projected onto a screen or the like.

  In the image forming unit 50, image formation is usually performed by the method as described above, but the light source light WL includes light rays other than visible light. Typical examples include UV light and IR light. When separation is performed by wavelength as described above, finally, UV light having a shorter wavelength than visible light is mainly included in blue light BL, and IR light having a longer wavelength than visible light is mainly included in red light RL. Will be. These often cause damage and deterioration of each component in the projector. In particular, the liquid crystal light valves 22, 23, 24 are greatly damaged and deteriorated by UV light and IR light. In this embodiment, in order to prevent UV light from damaging each component in the projector, the light is absorbed and removed at various locations. In particular, in the present embodiment, UV light absorption is performed in each mirror constituting the image forming unit 50. Hereinafter, the structure of the mirrors 10, 11, 12, and 13 used in this embodiment will be described.

  FIG. 2 is a cross-sectional view showing the structure of a mirror using UV absorbing glass used in the image forming unit 50 (see FIG. 1) which is a projection mechanism of the projector in the present embodiment.

  The mirror in this embodiment includes a UV-absorbing glass substrate AG that absorbs UV light, and a back-surface film F2 that coats a surface opposite to the surface film F1 that coats the light-incident surface of the UV-absorbing glass substrate AG. Consists of. As the UV absorbing glass AG, those disclosed in Japanese Patent Nos. 2852462 and 2645923 can be used.

  In the present embodiment, the surface film F1 is a dielectric multilayer film and plays a role of ensuring transmittance when visible light is incident. However, since it is necessary to transmit the UV light into the UV absorbing glass substrate AG, a dielectric multilayer film that transmits the UV light wavelength should be used. Therefore, in the present embodiment, a broadband multilayer dielectric multilayer film is used as the surface film F1. Since the broadband transmission type dielectric multilayer film has a property of transmitting light of a wide range of wavelengths, attenuation reduction of light source light can be prevented, and UV light can also be introduced into the UV absorbing glass substrate AG.

  In particular, in the present embodiment, it is desirable to use an AR coat having a very low visible light reflectance as the surface film F1. This ensures that visible light is transmitted without being reflected by the surface.

  In the present embodiment, the back film F2 is a metal film or a dielectric multilayer film. As the metal forming the former metal film, aluminum or silver is usually used. Since the metal film reflects light of all wavelengths, the UV absorbing glass substrate AG, the front film F1, and the back film F2 have a function as a mirror that bends the optical path of the light source light. Further, the light containing UV light is reflected on the back film F2 to be folded back in the UV absorbing glass substrate AG. In this case, as will be described later, the distance that the UV light passes through the UV-absorbing glass becomes longer, so that the amount of absorbed UV light increases. Even when the latter dielectric multilayer film is used for the back film F2, a film that reflects visible light is used. In particular, when a dielectric multilayer film that reflects UV light is used as the back film F2, the same effect as that obtained when a metal film is used can be obtained.

  As can be seen from the description related to FIG. 1, the mirror 10 reflects the light source light WL from the light source. Since the light source light WL includes light of all wavelengths, of course, UV light is also included. Therefore, if a mirror made of the above-described UV-absorbing glass substrate AG is used, effective UV light absorption can be performed.

  Similarly, UV light can be absorbed by using the above-described mirrors for the mirrors 11, 12, and 13. In particular, since the mirrors 12 and 13 exist in the optical path of the blue light BL that is considered to contain a lot of UV light, it is effective to perform the absorption twice here.

  Furthermore, in this embodiment, the dielectric multilayer film used for the front surface film F1 and the back surface film F2 is subjected to shading. Since the illumination light used for the projector is not parallel light, the incident angle of the illumination light with respect to the reflecting surface varies depending on the incident position. On the other hand, a normal dielectric multilayer film has an angle dependency in which a half value indicating transmission or reflection characteristics differs depending on an incident angle. Therefore, by performing shading, it is possible to perform more uniform transmission using a dielectric multilayer film that is optimal for the incident angle according to the incident position.

  In the present embodiment, the UV absorbing glass is used as a substrate material for the mirrors 10, 11, 12, and 13, but may be used as a substrate material for the dichroic mirrors 14 and 15 and the cross dichroic prism 25.

  The surface film F1 can be omitted for each of the mirrors 10, 11, 12, and 13. However, when the surface film F1 is provided, it is assumed to be a broadband transmission type dielectric multilayer film having the above transmission characteristics.

  FIG. 3 is a cross-sectional view for explaining the effect of using the UV absorbing glass in the reflection in the present invention. FIG. 3A shows a state in which the light source light is transmitted through a conventional UV absorbing glass plate, while FIG. 3B shows a mirror using the UV absorbing glass used in this embodiment. For comparison, the thickness of the UV absorbing glass is both d.

  As described above, in the UV light absorption method using a conventional ultraviolet cut filter or the like (hereinafter referred to as a light absorbing object), light is transmitted substantially perpendicularly to the light absorbing object. Therefore, the optical path through which the light passes through the light absorbing object is OP1, as shown in FIG. That is, the passing distance in the light absorbing object is d. On the other hand, in the present embodiment, since light is absorbed mainly at the time of reflection, the optical path passing through the mirror is OP2, as shown in FIG. When the incident angle is θ, the passing distance in the light absorbing object is 2d / cos θ. The amount of light absorption increases as the distance that light passes through the light-absorbing object increases. Therefore, when light is reflected by a parallel plate mirror inclined with respect to the optical axis, It can be said that there is an effect of 2 / cos θ times as compared with the case of transmitting substantially perpendicularly to the optical axis.

  In this embodiment, the mirror in the image forming unit has been described. However, it is possible to use a UV-absorbing glass mirror or lens that exhibits the same effect in other mechanisms through which light passes in the projector. It is.

[Second Embodiment]
In the first embodiment, the surface film F1 is a broadband transmissive dielectric multilayer film, and the back film F2 is a metal film or a dielectric multilayer film having the same effect as the metal film, but another dielectric having different optical characteristics. A multilayer film can be used for the front film F1 and the back film F2. The basic structure of the image forming unit is the same as in the first embodiment.

  In the present embodiment, a case where a dielectric multilayer film having a half value of an edge that transmits the short wavelength side of, for example, 430 ± 20 nm is used for one of the front film F1 and the back film F2. In this case, the dielectric multilayer film has UV transmission characteristics. In addition, as the dielectric multilayer film, a case where a dielectric multilayer film having a half value of an edge that transmits the long wavelength side is, for example, 700 ± 50 nm may be used. In this case, the dielectric multilayer film has IR transparency. Furthermore, a case where a visible light reflecting film having the above two characteristics is used as a dielectric multilayer film may be considered. Here, a dielectric multilayer film having UV transparency and a visible light reflection film are dealt with. In the third embodiment, a dielectric multilayer film having IR transparency is handled.

  Similarly, by using a dielectric multilayer film whose half value of the edge transmitting the short wavelength side is, for example, 490 ± 30 nm as one of the front film F1 or the back film F2, only blue light of a specific wavelength is partially reflected. If you want to.

  When the dielectric multilayer film having the characteristics described above is used as the back film F2, it is desirable to use a dielectric multilayer film that functions as an AR coat for visible light.

  FIG. 4 is a graph showing transmission / reflection characteristics of each dielectric multilayer film constituting the mirrors 10, 11, 12, and 13 according to the second embodiment.

  FIG. 4A shows the state of reflection / transmission of a dielectric multilayer film having UV transmission characteristics. The horizontal axis represents wavelength and the vertical axis represents transmittance. In the present invention, the problems directly related to the wavelength are the UV light region, the visible light region, and the IR light region, and the horizontal axis is divided by these three regions.

  Similarly, FIG. 4B is a reflection / transmission characteristic of a dielectric multilayer film having IR transparency, FIG. 4C is a reflection / transmission characteristic of a visible light reflection film, and FIG. It represents the reflection / transmission characteristics of a dielectric multilayer film that partially reflects blue light of a wavelength.

  By using the dielectric multilayer film as described above for the front film F1 and the back film F2, it is possible to absorb or remove UV light or the like. In this embodiment, a dielectric multilayer film having the characteristics shown in FIGS. 4A and 4D is used.

  FIG. 5A shows a broadband transmission type dielectric multilayer film (see FIG. 2 of the first embodiment) on the surface film F1, and a dielectric multilayer film having UV transparency on the back film F2 (see FIG. 4A). It is the figure which showed the mode of reflection and permeation | transmission of light at the time of using. Here, the solid line indicates UV light, and the broken line indicates light including visible light. In this case, the UV light passes through the surface film F1, passes through the UV absorbing glass substrate AG, and further passes through the back film F2. The UV light is absorbed to some extent by the UV absorbing glass substrate AG, and the remaining light is removed from the back surface film F2 to the outside of the optical device. Here, the back surface film F2 transmits UV light while reflecting visible light. As a result, the visible light is reflected without being attenuated and is efficiently used as illumination light. For example, if the dielectric multilayer film shown in FIG. 5A is used for the mirror 10 in FIG. 1, UV light can be absorbed and removed.

  Next, an example will be described in which the surface film F1 reflects visible light instead of being transmitted through a wide range. FIG. 5B is a diagram showing how light is reflected and transmitted when a dielectric multilayer film having visible light reflectivity (see FIG. 4A) is used as the surface film F1. A solid line indicates light including UV light, and a broken line indicates light including visible light. In this case, UV light is transmitted through the dielectric multilayer film and transmitted through the UV absorbing glass substrate AG, while visible light is reflected on the surface film F1. The UV light transmitted through the surface film F1 further passes through the UV absorbing glass substrate AG and reaches the back film F2. Here, by using a dielectric multilayer film having UV transparency (see FIG. 4A) for the back film F2, UV light can be removed out of the optical device. For example, if the dielectric multilayer film shown in FIG. 5B is used for the mirror 10 in FIG. 1, UV light can be absorbed and removed.

  As another combination, a dielectric multilayer film (see FIG. 4D) that reflects only blue light having a specific wavelength with a half value of 490 ± 30 nm as described above is used as the back film F2 for the mirrors 12 and 13. Can be considered. FIG. 5C is a diagram showing this state. A broken line is blue light of a specific wavelength, and a solid line is other blue light including UV light. At this time, if a wide-band transmission type dielectric multilayer film (see FIG. 2 of the first embodiment) is used for the surface film F1, UV light can be absorbed and removed, and the amount of blue light can be adjusted. Is possible.

  As in the first embodiment, the UV absorbing glass can also be used for the dichroic mirrors 14 and 15 and the cross dichroic prism 25 in the present embodiment.

  Also in this embodiment, it is assumed that the front film F1 and the back film F2 are shaded so that reflection or transmission is optimally performed.

  In this embodiment, the UV light is absorbed by the UV absorbing glass substrate AG. However, as described above, the UV light can be reliably removed by transmitting the UV light through the mirror. Is possible. Thus, when both the front surface film and the back surface film have UV light transmittance, the substrate of the mirror may not be UV absorbing glass. When the UV absorbing glass is not used, the amount of UV light removed outside the optical device increases. Therefore, the optical device external member that receives the removed UV light, such as the optical device cover, may be appropriately selected depending on the UV resistance.

[Third Embodiment]
In the embodiments so far, it has been mainly intended to absorb or remove UV light. However, as mentioned in the second embodiment, IR light can be removed depending on how to select a dielectric multilayer film. It is. In this embodiment, a case where a dielectric multilayer film having IR transparency is used will be described.

  FIG. 6A shows a wide-band transmission type dielectric multilayer film (see FIG. 2 of the first embodiment) on the surface film F1, and a dielectric multilayer film having IR transparency on the back film F2 (see FIG. 4B). It is the figure which showed the mode of reflection and permeation | transmission of light at the time of using. A solid line indicates IR light and a broken line indicates light including visible light. In this case, the IR light passes through the surface film F1, passes through the UV absorbing glass substrate AG, and further passes through the back film F2. On the other hand, visible light is reflected by the back film F2, and UV light is absorbed in the UV-absorbing glass substrate AG. Furthermore, if a visible light reflecting film (see FIG. 4C) is used for the back film F2, not only IR light but also UV light can be removed out of the optical device.

  FIG. 6B shows a case where a visible light reflecting film (see FIG. 4C) is used for the front film F1, and a dielectric multilayer film having IR transparency (see FIG. 4B) is used for the back film F2. It is the figure which showed the mode of reflection and permeation | transmission of light. A solid line indicates IR light, and a broken line indicates visible light. In this case, visible light is reflected by the surface film F1. The IR light passes through the surface film F1, passes through the UV-absorbing glass substrate AG, and further passes through the back film F2. On the other hand, the UV light is reflected by the back film F2 and absorbed in the UV absorbing glass substrate AG. Further, if a visible light reflecting film (see FIG. 4C) is used for the back film F2, the UV light is transmitted through the back film F2, and not only the IR light but also the UV light can be removed outside the optical device. .

  For example, in FIG. 1, if the above-described mirrors 10 and 11 that are considered to contain a large amount of IR light in incident light are used, IR light can be effectively removed.

  Similar to the first embodiment, the UV absorbing glass can also be used for the dichroic mirrors 14 and 15 and the cross dichroic prism 25 in the present embodiment.

  In the present embodiment, it is considered that UV light is absorbed by the UV absorbing glass substrate AG. However, when both the front surface film and the back surface film are UV light transmissive, the mirror substrate is The UV-absorbing glass may not be used.

  As is apparent from the above description, UV light and IR light can be effectively cut according to the first to third embodiments, so that deterioration of components is suppressed and the life of the product is extended. Further, by performing UV light absorption, UV light, and IR light removal with a mirror that is a part of a built-in component, the number of components can be reduced and the product weight can be reduced. Further, since UV light and IR light are absorbed not only during transmission but also during reflection, the distance over which the effect is exerted becomes longer than absorption through transmission.

  As described above, the present invention has been described according to the embodiment, but the present invention is not limited to the above embodiment. For example, a projector incorporating a DMD device that forms an image as well as a liquid crystal light valve can use the illumination device 1, the mirror, and the like of the above-described embodiment by appropriately changing according to specifications.

  Further, illumination light is obtained by uniformizing the light source light from the white light source with an appropriate optical system, which is a well-known projector of a type different from the present embodiment, and a single color is obtained by this illumination light. Even in a projector that directly illuminates a display-type liquid crystal light valve, it is possible to use the illuminating device 1, the mirror, or the like of the above-described embodiment by appropriately changing according to specifications.

  In addition, all the embodiments described above can be used in combination with, for example, a UV cut filter disposed on the optical path of the optical document or illumination light, for example, perpendicular to the optical axis. In this case, more effective UV light absorption, Can be removed.

  In this embodiment, the relay lenses 16 and 17 for correction are used in the optical path of blue light. However, the same correction is applied to the optical path of other color light, for example, red light by selecting the dichroic mirrors 14 and 15. A relay lens can be used. Also in this case, mirrors similar to the mirrors 10, 11, 12, and 13 can be disposed on the optical path of the illumination light, and UV light can be efficiently removed without increasing the weight.

It is a top view which shows the image formation part in the projector main body in embodiment which concerns on this invention. It is sectional drawing which shows the structure of the reflective mirror using UV absorption glass. (A), (b) is sectional drawing for demonstrating the effect of utilizing the reflection in this embodiment. (A), (b), (c), (d) is a graph which shows the permeation | transmission / reflection characteristic of a dielectric multilayer film. (A), (b), (c) is a figure which shows the mode of reflection and permeation | transmission of the light containing visible light and UV light which concern on 2nd Embodiment. (A), (b) is a figure which shows the mode of reflection and permeation | transmission of the light containing visible light and IR light which concern on 3rd Embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Illuminating device 10, 11, 12, 13 ... Mirror, F1 ... Front surface film, F2 ... Back surface film, AG ... UV absorption glass

Claims (12)

A light source device for generating light source light including visible light and ultraviolet light;
An optical system including an optical path conversion member that guides the light source light from the light source device to the object to be illuminated along a predetermined optical path as illumination light, and converts the optical path direction of the illumination light;
The optical device, wherein the optical path changing member is formed using UV absorbing glass that absorbs ultraviolet light from light source light.   The optical device, wherein the optical path changing member is a parallel flat plate that is arranged inclined with respect to the optical axis and reflects light source light, and has a dielectric multilayer film on the front surface, the back surface, or both.   3. The dielectric multilayer film includes a surface-side multilayer film that is formed on a surface side on which light source light is incident, transmits ultraviolet light, and is further subjected to shading with respect to visible light. Optical device.   4. The optical device according to claim 3, wherein the dielectric multilayer film includes a back surface side multilayer film that is formed on the back surface side and transmits ultraviolet light.   The optical apparatus according to claim 4, wherein the back side multilayer film reflects visible light.   The optical device according to claim 3, wherein the optical path conversion member has a metal film that reflects visible light on a back surface side.   The optical device according to claim 3, wherein the surface-side multilayer film is an antireflection film for visible light.   The optical apparatus according to claim 3, wherein the surface-side multilayer film reflects visible light. A light source device for generating light source light including visible light and ultraviolet light;
An optical system including an optical path conversion member that guides the light source light from the light source device to the object to be illuminated along a predetermined optical path as illumination light, and converts the optical path direction of the illumination light;
The optical path conversion member is a parallel plate arranged to be inclined with respect to the optical axis and reflecting light from the light source, and a dielectric multilayer film that transmits ultraviolet light and reflects visible light to at least one of the front and back surfaces. An optical device comprising:   The optical device according to claim 1, wherein the dielectric multilayer film transmits infrared light. An optical device according to any one of claims 1 to 10,
A light modulation device that is the object to be illuminated, illuminated by illumination light from the optical device;
A projection optical system that projects image light that has passed through the light modulation device;
A projector comprising: The optical device includes a light dividing unit that divides illumination light from the light source device into a plurality of color lights, and the light modulation device includes a plurality of color light modulation devices that individually modulate each color light,
12. The projector according to claim 11, wherein the optical path conversion member is disposed in an optical path of blue light divided by the light dividing means.

Images