JP2005122955A - Light source device, light source, and projector provided with these light source device or light source - Google Patents

Abstract

Provided is a light source device capable of improving the utilization rate of light source light by antifouling a member that reflects a light beam emitted from a light source.
In a light source device, a titanium oxide film 63 is formed as a part of a dielectric multilayer film 60 in the vicinity of a surface layer of a reflecting surface 131 of a sub-reflecting mirror, so that a light beam including ultraviolet rays emitted from a light source lamp is formed. Since the photocatalytic reaction is induced by the above, dust such as organic matter adhering to the reflecting surface 131 of the sub-reflecting mirror is decomposed and removed. In addition, even if dew condensation occurs on the reflecting surface 131 of the sub-reflecting mirror, it is hydrophilized by the photocatalytic reaction, so that traces of contact with water droplets hardly remain, and in this respect as well, the reflecting surface 131 is prevented from being stained. Therefore, the luminous flux emitted from the light source lamp is reliably reflected by the sub-reflecting mirror, so that the reflectance can be prevented from decreasing due to fogging of the reflecting surface 131, and the light source light utilization rate can be greatly improved.
[Selection] Figure 5

Description

  The present invention relates to a light-emitting portion that emits light between electrodes, a light-emitting tube having sealing portions provided at both ends of the light-emitting portion, and a reflector that emits light emitted from the light-emitting tube in a certain direction. And a sub-reflecting mirror having a reflecting surface disposed opposite to the reflecting surface of the reflector, covering a front side of the light emitting direction of the arc tube, and reflecting the light beam emitted from the arc tube to the reflector. .

2. Description of the Related Art Conventionally, a projector that modulates a light beam emitted from a light source according to image information and enlarges and projects an optical image is known and used for presentations in meetings and the like together with a personal computer. In recent years, it has also been used for home theater applications in response to the need to watch movies on a large screen at home.
In such a projector, in order to project a clearer optical image, a discharge arc tube that emits light with high brightness, such as a metal halide lamp or a high-pressure mercury lamp, is employed as a light source. These discharge-type arc tubes have a spherical light emitting portion where discharge light is emitted between a pair of electrodes, and a sealing portion provided at both ends of the light emitting portion and encapsulating metal foil for applying voltage to the electrodes And a rare gas and a small amount of halogen are enclosed, and radiates a light beam including powerful ultraviolet light (see, for example, Patent Document 1).
Then, the emitted light beam is reflected by a reflecting member such as a reflector having an increased reflection film formed on a base material made of glass or the like as an insulator, and is aligned in a predetermined direction and used for illumination or the like.

JP 2002-350778 A ([0015] paragraph, FIG. 4)

However, a reflective member made of glass or the like is relatively easily charged, and dust or the like floating in the outside air is easily attached by static electricity. When this dust or the like adheres, a chemical change is induced and the surface of the reflector may be altered. Furthermore, dew condensation may occur on the surface of the reflecting member, and the organic substance contained in the water droplets may remain in the form of a ring stain.
When the reflecting surface of the reflecting member is clouded by dust, condensation, etc., the reflectance is impaired. That is, there is a problem that even when high-luminance light is emitted from the arc tube as described above, the use of the light source light is limited.
Here, it is conceivable that the dust is forcibly removed by blowing with a fan, but there is a possibility that the arc tube is cooled by blowing and the halogen cycle is damaged, or the arc tube becomes hot and devitrified. Therefore, it is difficult to control the air flow, and since the reflecting members such as the arc tube and the reflector are close to each other, it is difficult to obtain a sufficient antifouling effect.

  An object of the present invention is to provide a light source device, a light source, and a light source device or a light source that can improve the utilization factor of light source light by antifouling a member that reflects a light beam emitted from the light source. It is to provide a projector.

A light source device according to the present invention includes a light emitting portion that performs discharge light emission between electrodes, a light emitting tube having sealing portions provided at both ends of the light emitting portion, and a light beam emitted from the light emitting tube aligned in a certain direction. A reflector that emits light, and a sub-reflector that has a reflecting surface disposed opposite to the reflecting surface of the reflector and that covers the front side of the light emitting direction of the arc tube and reflects the light beam emitted from the arc tube to the reflector. The reflective surface of the sub-reflecting mirror is configured as a dielectric multilayer film in which a plurality of films having different refractive indexes are laminated, and a layer having a photocatalytic function is provided in the vicinity of the surface layer of the reflective surface. Is formed.
In the light source device of the present invention, the reflecting surface of the reflector is configured as a dielectric multilayer film in which a plurality of films having different refractive indexes are laminated, and a layer having a photocatalytic function is provided near the surface layer of the reflecting surface. Preferably it is formed.
Furthermore, the light source of the present invention covers a light emitting portion where discharge light emission is performed between electrodes, a light emitting tube having sealing portions provided at both ends of the light emitting portion, and a front side of the light emitting portion of the light emitting portion in the light emission direction. A light source including a sub-reflecting mirror, wherein the reflecting surface of the sub-reflecting mirror is configured as a dielectric multilayer film in which a plurality of films having different refractive indexes are laminated, and a photocatalyst is provided near the surface layer of the reflecting surface. A layer having a function is formed. When using this light source, the arc tube may be set on the reflector, but the light source light may be collected by another means.

Here, as the reflector, an elliptical reflector having an ellipsoidal reflection surface can be employed. In addition, a sub-reflecting mirror can be mounted so as to cover approximately half of the light-emitting portion, and the light beam emitted from the arc tube to the side opposite to the reflector can be reflected to the reflector by the sub-reflecting mirror. Thereby, most of the light source light can be used, and the sealing portion can be protruded from the reflector, so that the light source device can be downsized.
In order to cool the arc tube, the sub-reflecting mirror is preferably mounted with a gap between the arc tube and the arc tube. As a material of the reflector and the sub-reflecting mirror, quartz or the like having a small thermal expansion coefficient can be adopted.
The dielectric multilayer film can be formed, for example, by laminating a film made of high refractive index tantalum pentoxide (Ta ₂ O ₅ ) and a film made of low refractive index silicon dioxide (SiO ₂ ). These inorganic materials such as Ta ₂ O ₅ and SiO ₂ are not easily deteriorated by light. Further, if the high refractive index layer and the low refractive index layer are alternately laminated, for example, several tens of layers, the reflection enhancement effect can be further enhanced.
Here, the film having the photocatalytic function also constitutes a layer of the dielectric multilayer film. As one of the semiconductor photocatalysts, titanium oxide (titania TiO ₂ ), which is an n-type semiconductor, is known. For example, a dielectric multilayer film including Ta ₂ O ₅ and SiO ₂ stacked alternately is formed. In this case, TiO ₂ having a high refractive index can be arranged at a position where Ta ₂ O ₅ is laminated in the vicinity of the surface layer of the reflecting surface. In addition to functioning as a photocatalyst, this TiO ₂ constitutes a part of the dielectric multilayer film and can contribute to increased reflection.
In addition to Ta ₂ O ₅ , TiO ₂ , tantalum oxide (Ta ₂ O ₃ ), zirconium oxide (zirconia · ZrO ₂ ), or the like can be used as the high refractive index layer. In addition to SiO ₂ , magnesium fluoride (MgF ₂ ), aluminum oxide (alumina / Al ₂ O ₃ ), etc. can be used as the low refractive index layer.

According to the above invention, a photocatalytic reaction is induced according to the light component emitted from the arc tube, so that organic substances, gases, etc. adhering to the reflecting surface of the sub-reflecting mirror are decomposed and removed. In addition, even when condensation occurs on the reflecting surface of the sub-reflecting mirror, the substance that becomes a contact mark with water droplets is also decomposed by the photocatalytic reaction. Moreover, if light is irradiated in the dewed state, it is possible to prevent organic substances inside the water droplets from collecting on the surface of the water droplets and sticking to the reflecting surface due to the hydrophilizing action of the photocatalyst. Thereby, the adhesion of dust floating in the air to the reflection surface can be prevented.
Therefore, the light source light is reliably reflected by the sub-reflecting mirror by such an antifouling action, and the reduction in reflectance due to fogging of the reflection surface is prevented and the utilization rate of the light source light is improved without using fan blowing. Can do.
Similarly, when a film having a photocatalytic function is also formed on the reflector, the reflectance of the reflector can be prevented from being lowered, and the utilization factor of the light source can be further improved.
Here, when the arc tube is a metal halide lamp or an ultra-high pressure mercury lamp that emits light containing strong ultraviolet rays and TiO ₂ whose photocatalytic reaction is activated by ultraviolet rays is adopted as a photocatalyst, the photo component is a photocatalyst. Therefore, the antifouling effect can be further enhanced.

In the light source device of the present invention, the layer having a photocatalytic function is preferably made of anatase TiO ₂ .
According to this invention, the anatase type TiO ₂ has higher catalytic activity than the rutile type, has a large band gap, and the semiconductor photocatalytic reaction is activated not only by ultraviolet rays but also by visible light, so that the antifouling effect is further enhanced. Can be improved.

Furthermore, in the light source device of the present invention and the light source of the present invention, it is preferable that a layer having a photocatalytic function is formed on the outer peripheral surface of the light emitting portion.
Here, it is difficult to remove dust adhering to the luminous hall by air blowing, especially when the space between the sub-reflecting mirror and the arc tube is narrow. Even if removal is possible, the arc tube is cooled and the halogen cycle is affected. It is easy to come out.
On the other hand, according to these inventions, the organic matter or the like attached to the arc tube is decomposed by the photocatalytic reaction, so that the luminous flux emitted from the inside of the arc tube is emitted outside without being disturbed by dust or the like. Even if not, the light source light can be used without loss.
Note that TiO ₂ as described above can be adopted as a photocatalytic substance formed on the arc tube.

In the light source device of the present invention, it is preferable that the sub-reflecting mirror is made of a material having a thermal conductivity of 10 W / (m · K) or more.
Here, as a material having a thermal conductivity of 10 W / (m · K) or more, sapphire, YAG (Y ₃ Al ₅ O ₁₂ ) or the like can be employed.
According to the present invention, since the subreflector becomes relatively low temperature due to high thermal conductivity and the amount of thermal expansion is reduced, peeling of the dielectric multilayer film can be prevented, and the material and thickness of the film can be designed. In addition, the degree of freedom of film forming conditions can be improved.

A light source device according to the present invention includes a light emitting portion that performs discharge light emission between electrodes, a light emitting tube having sealing portions provided at both ends of the light emitting portion, and a light beam emitted from the light emitting tube aligned in a certain direction. A reflector that emits light, and a sub-reflector that has a reflecting surface disposed opposite to the reflecting surface of the reflector and that covers the front side of the light emitting direction of the arc tube and reflects the light beam emitted from the arc tube to the reflector. The sub-reflecting mirror is made of a translucent material, and a film having translucency and having a photocatalytic function is formed on the inner peripheral surface of the sub-reflecting mirror, The reflecting surface is configured as the dielectric multilayer film formed on the outer peripheral surface of the sub-reflecting mirror.
Here, quartz, YAG (Y ₃ Al ₅ O ₁₂ ), sapphire, or the like can be employed as the translucent material, and a film having translucency and a photocatalytic function can be formed of TiO ₂ or the like.
Further, it is preferable to form an antireflection film (AR coating / Anti Reflection Coating) on the inner peripheral surface side of the sub-reflecting mirror. The antireflection film may be a single layer film, but may be formed by laminating films having different refractive indexes, such as a dielectric multilayer film. The antireflection film and the dielectric multilayer film are appropriately designed in terms of the film material, film thickness, stacking order, number of layers, etc. of each layer according to the corresponding light wavelength in consideration of peeling due to thermal expansion.

According to this invention, the light source light passes through the film having translucency and photocatalytic function formed on the inner peripheral surface of the sub-reflecting mirror, and is formed on the outer peripheral surface side of the sub-reflecting mirror. Is reflected by. The organic matter, gas, water droplets, etc. adhering to the inner peripheral surface of the sub-reflecting mirror are decomposed and hydrophilized by the photocatalytic reaction, so that the translucency from the inner peripheral surface to the outer peripheral surface of the sub-reflecting mirror is maintained. It is possible to prevent a decrease in reflectance.
Here, in the sub-reflecting mirror as described above, since the reflecting surface is formed on the inner peripheral surface side close to the arc tube, it is necessary to form the dielectric multilayer film with a material having high heat resistance. On the other hand, since the reflecting surface is formed on the outer peripheral surface side in this sub-reflecting mirror, the temperature of the reflecting surface can be lowered. Therefore, it is possible to improve the degree of freedom in selecting the material of the dielectric multilayer film constituting the reflecting surface.

A projector according to the present invention is a projector that modulates a light beam emitted from a light source in accordance with image information to form an optical image and projects the enlarged image, and includes the light source device or the light source described above. To do.
According to the present invention, since the light source device has the operations and effects as described above, it is possible to provide a projector that can enjoy the same operations and effects and improve the utilization rate of the light source light.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[1] First embodiment (configuration of projector)
FIG. 1 is a schematic diagram showing an optical system of a projector 1 according to the first embodiment of the present invention. The projector 1 modulates a light beam emitted from a light source according to image information to produce an optical image. , And enlarged and projected on a screen, and includes a light source device 10, a uniform illumination optical system 20, a color separation optical system 30, a relay optical system 35, an optical device 40, and a projection optical system 50. The optical elements constituting these optical systems 20 to 35 are positioned and adjusted and accommodated in the light guide 2 in which a predetermined illumination optical axis A is set.

The light source device 10 emits a light beam emitted from the light source lamp 11 in a fixed direction and illuminates the optical device 40. As will be described in detail later, the light source lamp 11, the elliptical reflector 12, and the sub-reflecting mirror 13 are used. Although not shown, the explosion-proof glass 14 and a lamp housing for holding these are provided, and a collimating concave lens 15 is provided at the rear stage of the elliptical reflector 12 in the light beam emission direction. The collimating concave lens 15 may be integrated with the light source device 10 or may be a separate body.
The light beam emitted from the light source lamp 11 is emitted as convergent light by aligning the emission direction toward the front side of the apparatus by the elliptical reflector 12, collimated by the collimating concave lens 15, and emitted to the uniform illumination optical system 20.

The uniform illumination optical system 20 is an optical system that divides the light beam emitted from the light source device 10 into a plurality of partial light beams and uniformizes the in-plane illuminance of the illumination area. The first lens array 21 and the second lens array 22 are used. , A polarization conversion element 23, a superimposing lens 24, and a reflection mirror 25.
The first lens array 21 has a function as a light beam splitting optical element that splits the light beam emitted from the light source lamp 11 into a plurality of partial light beams, and is arranged in a matrix in a plane orthogonal to the illumination optical axis A. A plurality of small lenses are provided, and the contour shape of each small lens is set so as to be substantially similar to the shape of the image forming area of the liquid crystal panels 42R, 42G, and 42B constituting the optical device 40 described later. Yes.
The second lens array 22 is an optical element that collects a plurality of partial light beams divided by the first lens array 21 described above, and in the same manner as the first lens array 21, a matrix is formed in a plane orthogonal to the illumination optical axis A. However, since it is intended to collect light, the outline shape of each small lens corresponds to the shape of the image forming area of the liquid crystal panels 42R, 42G, and 42B. There is no need.

The polarization conversion element 23 is a polarization conversion element that aligns the polarization direction of each partial light beam divided by the first lens array 21 with linear polarization in one direction.
Although not shown, the polarization conversion element 23 has a configuration in which polarization separation films and reflection mirrors that are inclined with respect to the illumination optical axis A are alternately arranged. The polarization separation film transmits one polarized light beam among the P-polarized light beam and S-polarized light beam included in each partial light beam, and reflects the other polarized light beam. The other polarized light beam reflected is bent by the reflecting mirror and emitted in the emission direction of the one polarized light beam, that is, the direction along the illumination optical axis A. One of the emitted polarized light beams is polarized and converted by a phase difference plate provided on the light beam exit surface of the polarization conversion element 23, and the polarization directions of all the polarized light beams are aligned. By using such a polarization conversion element 23, the light beam emitted from the light source lamp 11 can be aligned with a polarized light beam in one direction, so that the utilization rate of the light source light used in the optical device 40 can be improved. it can.

The superimposing lens 24 condenses a plurality of partial light beams that have passed through the first lens array 21, the second lens array 22, and the polarization conversion element 23, and superimposes them on the image forming regions of the liquid crystal panels 42R, 42G, and 42B. It is. In this example, the superimposing lens 24 is a spherical lens in which the incident-side end surface of the light beam transmission region is flat and the exit-side end surface is spherical, but an aspherical lens whose exit-side end surface is a hyperboloid can also be used.
The light beam emitted from the superimposing lens 24 is bent by the reflection mirror 25 and emitted to the color separation optical system 30.

The color separation optical system 30 includes two dichroic mirrors 31 and 32, and a reflection mirror 33. A plurality of partial light beams emitted from the uniform illumination optical system 20 from the dichroic mirrors 31 and 32 are converted into red (R), It has a function of separating light of three colors, green (G) and blue (B).
The dichroic mirrors 31 and 32 are optical elements in which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam of another wavelength is formed on the substrate. The dichroic mirror 31 disposed in the front stage of the optical path is A mirror that transmits red light and reflects other color light. The dichroic mirror 32 disposed in the latter stage of the optical path is a mirror that reflects green light and transmits blue light.

  The relay optical system 35 includes an incident side lens 36, a relay lens 38, and reflection mirrors 37 and 39, and has a function of guiding the blue light transmitted through the dichroic mirror 32 constituting the color separation optical system 30 to the optical device 40. Have. The reason why such a relay optical system 35 is provided in the optical path of the blue light is that the optical path length of the blue light is longer than the optical path lengths of the other color lights, so that the light use efficiency is reduced due to light divergence or the like. It is for preventing. In this example, since the optical path length of blue light is long, such a configuration is used. However, a configuration in which the optical path length of red light is increased is also conceivable.

  The red light separated by the dichroic mirror 31 described above is bent by the reflection mirror 33 and then supplied to the optical device 40 via the field lens 41. The green light separated by the dichroic mirror 32 is supplied to the optical device 40 through the field lens 41 as it is. Further, the blue light is condensed and bent by the lenses 36 and 38 and the reflecting mirrors 37 and 39 constituting the relay optical system 35 and supplied to the optical device 40 via the field lens 41. The field lens 41 provided in the front stage of the optical path of each color light of the optical device 40 is provided to convert each partial light beam emitted from the second lens array 22 into a light beam parallel to the illumination optical axis. Yes.

  The optical device 40 modulates an incident light beam according to image information to form a color image, and includes liquid crystal panels 42R, 42G, and 42B as light modulation devices to be illuminated, and a color combining optical system. And a cross dichroic prism 43. An incident-side polarizing plate 44 is interposed between the field lens 41 and the liquid crystal panels 42R, 42G, and 42B. Although not shown, between the liquid crystal panels 42R, 42G, and 42B and the cross dichroic prism 43, the illustration is omitted. In this case, an exit side polarizing plate is interposed, and light modulation of incident color light is performed by the entrance side polarizing plate 44, the liquid crystal panels 42R, 42G, and 42B, and the exit side polarizing plate.

  The liquid crystal panels 42R, 42G, and 42B are a pair of transparent glass substrates in which liquid crystal, which is an electro-optical material, is hermetically sealed. For example, incident side polarization is performed according to a given image signal using a polysilicon TFT as a switching element. The polarization direction of the polarized light beam emitted from the plate 44 is modulated. The image forming area for modulating the liquid crystal panels 42R, 42G, and 42B is rectangular, and the diagonal dimension is 0.7 inches, for example.

The cross dichroic prism 43 is an optical element that synthesizes an optical image modulated for each color light emitted from the exit side polarizing plate to form a color image. The cross dichroic prism 43 has a substantially square shape in plan view in which four right angle prisms are bonded together, and a dielectric multilayer film is formed on the interface where the right angle prisms are bonded together. One of the approximately X-shaped dielectric multilayer films reflects red light, and the other dielectric multilayer film reflects blue light. These dielectric multilayer films cause red light and blue light to be reflected. The light is bent and aligned with the traveling direction of the green light, so that the three color lights are synthesized.
The color image emitted from the cross dichroic prism 43 is enlarged and projected by the projection optical system 50 to form a large screen image on a screen (not shown).

(Configuration of light source device)
As shown in FIG. 2, the light source device 10 has a configuration in which a light source lamp 11 as an arc tube is arranged inside an elliptical reflector 12.
The light source lamp 11 as a light emitting tube is formed of a quartz glass tube having a central portion swelled in a spherical shape, and a central portion is a light emitting portion 111 and portions extending on both sides of the light emitting portion 111 are sealing portions 112.

Inside the light emitting unit 111, a pair of tungsten electrodes 111A spaced apart from each other, mercury, a rare gas, and a small amount of halogen are enclosed, and an ultrahigh pressure mercury lamp is configured. As the type of the light source lamp 11, a metal halide lamp, a high-pressure mercury lamp, a halogen lamp, a xenon lamp, or the like can be selected according to the type of photocatalyst described later.
Inside the sealing part 112 extending to both sides of the light emitting part 111, molybdenum metal foils 112A electrically connected to the electrodes of the light emitting part 111 are respectively inserted and sealed with a glass material or the like. . Each metal foil 112 </ b> A is further connected to a lead wire 113 as an electrode lead wire, and the lead wire 113 extends to the outside of the light source lamp 11.
As shown in FIG. 3, a photocatalytic film 111 </ b> B having a photocatalytic function is formed on the outer peripheral surface of the light emitting unit 111. For this reason, it is good to make the light emission part 111 thick and make it heat-resistant.
The photocatalytic film 111B is a titanium oxide (TiO ₂ ) thin film formed by vapor deposition by a method described later.
When a voltage is applied to the lead wire 113, as shown in FIG. 3, a potential difference is generated between the electrodes 111A via the metal foil 112A, a discharge is generated, an arc image D is generated, and the light emitting unit 111 emits light. The light source lamp 11 is an ultra-high pressure mercury lamp and radiates a light beam including strong ultraviolet rays.

The elliptical reflector 12 is an integrally molded product made of quartz glass provided with a neck part 121 through which the sealing part 112 on the proximal end side of the light source lamp 11 is inserted and an elliptical reflecting part 122 extending from the neck part 121. It is. In addition to quartz glass having a small coefficient of thermal expansion, sapphire having a high thermal conductivity, YAG (Y ₃ Al ₅ O ₁₂ ), or the like can also be employed.
An insertion hole 123 is formed at the center of the neck portion 121, and the sealing portion 112 is disposed at the center of the insertion hole 123.
As will be described later, the reflective portion 122 is configured by depositing a dielectric multilayer film 70 on the entire surface of an elliptical inner peripheral surface 122B to form a reflective surface 122A. The reflecting surface 122A is a cold mirror that reflects visible light and transmits infrared light.
Further, the edge of the reflecting portion 122 on the expansion side is formed in a stepped shape, and the explosion-proof glass 14 is bonded to the end surface to cover the light beam emission surface of the elliptical reflector 12.

In the light source lamp 11 arranged inside the reflection part 122 of the elliptical reflector 12, the light emission center between the electrodes 111A in the light emission part 111 is in the vicinity of the first focal position L1 of the elliptical surface of the reflection surface 122A of the reflection part 122. It arrange | positions so that it may become.
When the light source lamp 11 is turned on, the light beam emitted from the light emitting unit 111 is reflected by the reflecting surface 122A of the reflecting unit 122 and becomes converged light that converges to the second focal position L2 of the elliptical surface.

When fixing the light source lamp 11 to such an elliptical reflector 12, the sealing portion 112 of the light source lamp 11 is inserted into the insertion hole 123 of the elliptical reflector 12, and the light emission center between the electrodes 111 </ b> A in the light emitting portion 111 is reflected. It arrange | positions so that it may become the 1st focus position L1 of the elliptical surface of the part 122, and the inside of the insertion hole 123 is filled with the inorganic type adhesive which has a silica / alumina as a main component.
Further, the dimension of the reflecting portion 122 in the optical axis direction is shorter than the length of the light source lamp 11. When the light source lamp 11 is fixed to the elliptical reflector 12 in this way, the sealing portion on the front side of the light source lamp 11 is used. 112 protrudes from the light beam exit opening of the elliptical reflector 12.

The sub-reflecting mirror 13 is a reflecting member that covers approximately half of the light emitting portion 111 of the light source lamp 11 on the front side in the light emission direction. As shown in FIG. 4, the inner peripheral surface 130 is spherical and the outer peripheral surface 132 is inner peripheral. It is formed in a bowl shape that is curved to follow the curvature of the surface 130.
An opening 133 is formed in the bottom surface of the bowl shape of the sub-reflecting mirror 13, and the inner peripheral surface of the opening 133 is an adhesive surface 134 filled with an adhesive for fixing to the sealing portion 112. The
This sub-reflecting mirror 13 is formed by polishing a thick cylindrical member made of quartz glass, and one end surface of this cylindrical member is polished into a concave curved surface to form an inner peripheral surface 130. An outer peripheral surface 132 is formed by polishing into a convex curved surface so as to follow the inner peripheral surface 130. In addition to the quartz glass material, sapphire, YAG (Y ₃ Al ₅ O ₁₂ ), etc. can be employed in substantially the same manner as the elliptical reflector 12.
Here, as will be described below, a dielectric multilayer film 60 is deposited on the entire inner peripheral surface 130 to form a reflective surface 131, which is a cold mirror. The dielectric multilayer film 60 has substantially the same configuration as the dielectric multilayer film 70 of the elliptical reflector 12.

When such a sub-reflecting mirror 13 is attached to the light source lamp 11, the sub-reflecting mirror 13 is bonded and fixed with an adhesive interposed between the adhesive surface 134 and the outer peripheral surface of the sealing portion 112 of the light source lamp 11. As the material of the adhesive, a silica / alumina-based inorganic adhesive can be employed as in the case where the light source lamp 11 is bonded and fixed to the elliptical reflector 12.
At this time, in order to cool the light source lamp 11, a gap may be left between the reflecting surface 131 of the sub-reflecting mirror 13 and the light source lamp 11 (see FIG. 3).

In the sub-reflecting mirror 13 and the elliptical reflector 12 described above, as shown in FIG. 5, the reflecting surfaces 131 and 122A are configured as dielectric multilayer films 60 and 70, respectively.
Here, the dielectric multilayer film 60 of the sub-reflecting mirror 13 includes a tantalum film 61 made of Ta ₂ O ₅ having a high refractive index and a silica film 62 made of SiO ₂ having a low refractive index, which are alternately laminated in several tens of layers. Therefore, the reflection-enhancing film has enhanced reflection. The high refractive index layer may be a film made of TiO ₂ , tantalum oxide (Ta ₂ O ₃ ), zirconium oxide (zirconia · ZrO ₂ ) or the like, and the low refractive index layer may be magnesium fluoride (MgF ₂ ) or oxidized. A film made of aluminum (alumina / Al ₂ O ₃ ) or the like may be used. These inorganic materials are not easily deteriorated by light.
In the vicinity of the surface layer of the dielectric multilayer film 60, a titanium oxide film 63 made of TiO _{2 as} a semiconductor photocatalyst is laminated so as to form one layer of the dielectric multilayer film 60. Here, since the linear thermal expansion coefficient of TiO ₂ is relatively large, the thickness of the titanium oxide film 63 is set thin in order to prevent peeling. Further, TiO ₂ contained in the titanium oxide film 63 has a band gap of about 3 eV, and a photocatalytic reaction is induced mainly by ultraviolet light.
Further, a silica film 62 excellent in oxidation resistance and heat resistance is laminated on the titanium oxide film 63 to form the outermost layer of the reflection surface 131 of the sub-reflection mirror 13. Therefore, the titanium oxide film 63 is a second layer counted from the surfaces of the reflecting surfaces 122A and 131, and corresponds to a layer having a photocatalytic function.
The outermost silica film 62 covers the lower titanium oxide film 63 and the like, thereby protecting the titanium oxide film 63 from the high heat generated by the light source and preventing the photocatalytic function from being hindered by redox. doing. However, since TiO ₂ has a relatively high oxidation resistance, the titanium oxide film 63 can be used as the outermost layer without being coated with the silica film 62, but it maintains the crystal structure of TiO ₂ and exhibits high photocatalytic activity. In order to achieve this, it is better to coat the silica in this way. Moreover, since SiO ₂ has relatively high hydrophilicity, it can also contribute to the hydrophilization action of the photocatalyst described later.
The dielectric multilayer film 70 of the elliptical reflector 12 is also laminated with a tantalum film 71, a silica film 72, and a titanium oxide film 73 in substantially the same manner as the dielectric multilayer film 60. The dielectric multilayer films 60 and 70 are made of the film material, film thickness, stacking order, and number of layers of the films 61, 62, 63, 71, 72, and 73 according to the wavelength of light emitted from the light source lamp 11. Etc. are appropriately designed.

For example, dielectric multilayer films 60 and 70 are formed on the sub-reflecting mirror 13 and the elliptical reflector 12 as follows, and the reflecting surfaces 131 and 122A are formed. Here, an ellipse to which a negative voltage is applied to the vapor flow of Ta ₂ O ₅ , SiO ₂ , and TiO ₂ ionized in a high vacuum by ion plating, which is a kind of physical vapor deposition (PVD). It is made to collide with the base-material surface of the reflector 12 and the sub-reflecting mirror 13, and it reacts with gas, and forms a film. As a raw material of TiO ₂ , an organic titanium compound centered on an alkoxide can be used.
The photocatalytic film 111B of the light emitting unit 111 is also formed by ion plating in substantially the same manner.
By such ion plating, a hard and dense thin film can be obtained at a relatively low reaction temperature. Furthermore, since the base material of the sub-reflecting mirror 13 and the elliptical reflector 12 does not need to be high during film formation, distortion of the reflecting surfaces 131 and 122A can be prevented and shape accuracy can be ensured.

As a specific film forming procedure, first, as shown in FIG. 5, a tantalum film 61 of Ta ₂ O ₅ is formed at about 300 ° C. on the surface of the base material of the sub-reflecting mirror 13. Here, since Ta ₂ O ₅ has a linear expansion coefficient similar to that of quartz, which is the material of the sub-reflecting mirror 13, the tantalum film 61 is difficult to peel off from the surface of the sub-reflecting mirror 13.
Next, a silica film 62 made of SiO ₂ is formed in the same manner on the tantalum film 61 thus formed. Then, the tantalum film 61 and the silica film 62 are alternately formed, and several tens of layers are laminated so that the silica film 62 becomes a surface layer.
A titanium oxide film 63 is further formed at about 200 ° C. on the silica film 62 as a surface layer as a result of the lamination of several tens of layers. Further, on this titanium oxide film 63, a silica film 62 which is the outermost layer of the dielectric multilayer film 60 is formed.
Note that the dielectric multilayer film 70 of the elliptical reflector 12 is formed in substantially the same manner. As a result, the dielectric multilayer films 60 and 70 are formed in order from the outermost layer, silica films 62 and 72, titanium oxide films 63 and 73, silica films 62 and 72, tantalum films 61 and 71, silica films 62 and 72, and tantalum films. 61, 71 ... Omitted in the middle (silica films 62, 72 and tantalum films 61, 71 alternately) ... bases of silica films 62, 72, tantalum films 61, 71, sub-reflector 13 and elliptical reflector 12 The material inner peripheral surfaces 130 and 122B are formed.

When the light beam is emitted from the inside of the light emitting unit 111, the light beam is transmitted through the outer peripheral surface of the light emitting unit 111 and reaches the titanium oxide films 73 and 63 formed in the vicinity of the surface layers of the elliptical reflector 12 and the sub-reflecting mirror 13. At this time, a photocatalytic reaction of TiO ₂ occurs on the outer peripheral surface of the light emitting portion 111 and the reflecting surfaces 122A and 131 of the elliptical reflector 12 and the sub-reflecting mirror 13. By this photocatalytic reaction, organic substances, gases, and the like attached to the reflecting surfaces 122A and 131 of the elliptical reflector 12 and the sub-reflecting mirror 13 are decomposed. Specifically, this decomposition action is due to a photocatalytic oxidation reaction in which TiO _{2 of the} titanium oxide film absorbs light centering on ultraviolet light and charge separation occurs, and organic substances adsorbed in this state are oxidatively decomposed. .
Here, the gap between the sealing portion 112 and the sub-reflecting mirror 13 is narrow, and even if air is blown into the narrow gap with a fan or the like, cleaning is difficult. Since there is a possibility that the cycle is damaged or the light source lamp 11 becomes hot and devitrified, it is difficult to control the air flow. Along with this, there is a possibility that the rotational sound of the fan becomes noise or the life of the light source lamp 11 is shortened.
However, even if it does not depend on such a blowing means, the organic substance, gas, etc. which float on the outside air are decomposed | disassembled by irradiating light to the reflective surfaces 122A and 131 whole, and these reflective surfaces 122A and 131 are clouded by dirt. Can be protected from.
Further, even when water droplets adhere to the reflecting surfaces 122A and 131 due to the dew condensation phenomenon such as when the projector 1 is not used, the organic substances remaining after evaporation of the water droplets are also decomposed by the decomposition action of the photocatalyst.
In addition, when the light source lamp 11 is turned on in the dewed state, water droplets are adsorbed by the photocatalytic reaction and become hydrophilic, and the contact angle with the reflecting surfaces 122A and 131 approaches 0 °. It is possible to prevent the water from being collected on the surface of the water droplet and sticking to the reflecting surfaces 122A and 131.
As described above, it is possible to prevent dust in the air from adhering to the reflecting surfaces 122A and 131 due to decomposition of organic substances, gases, and the like. Therefore, the light source light from the light source lamp 11 converges to the second focal position L2 without being disturbed by dust or the like.

(Effect of embodiment)
According to such 1st Embodiment, there exist the following effects.
(1-1) In the light source device 10, the titanium oxide film 63 is formed as the second layer of the dielectric multilayer film 60 in the vicinity of the surface layer of the reflecting surface 131 of the sub-reflecting mirror 13. Since the photocatalytic reaction is induced by the luminous flux including the ultraviolet rays, the organic substances and gases attached to the reflecting surface 131 of the sub-reflecting mirror 13 are decomposed and removed, and dust does not adhere to the reflecting surface 131. In addition, even if dew condensation occurs on the reflecting surface 131 of the sub-reflecting mirror 13, it is hydrophilized by the photocatalytic reaction, so that contact traces with water droplets hardly remain, and in this respect also, the reflecting surface 131 is prevented from being stained. As described above, this is effective in cleaning the gap between the sub-reflecting mirror 13 and the sealing portion 112 where it is difficult to prevent contamination by fan blowing.
Therefore, the luminous flux emitted from the light source lamp 11 is reliably reflected by the sub-reflecting mirror 13, and the reduction in reflectance due to fogging of the reflecting surface 131 is prevented, and the utilization rate of the light source light converged to the second focal position L2 is reduced. It can be greatly improved.
Furthermore, in the light source device 10, the light source light emitted from the light emitting unit 111 is reliably emitted to the outside and reliably reflected by the elliptical reflector 12 and the sub-reflecting mirror 13, thereby achieving a predetermined illumination luminance of the light source device 10. And the reliability of the product can be improved.

(1-2) As the light source lamp 11, an ultra-high pressure mercury lamp that emits light including strong ultraviolet rays is employed, and TiO ₂ is employed as a photocatalyst, so that the photo component is adapted to the properties of the photocatalyst, Since the photocatalytic reaction of TiO ₂ is activated by ultraviolet rays, the antifouling effect can be further enhanced.
Moreover, since ultraviolet light is utilized for antifouling in this way and ultraviolet light emitted from the light source device 10 can be reduced, deterioration of components including organic materials such as the liquid crystal panels 42R, 42G, and 42B is prevented. it can.
(1-3) Since the titanium oxide film 73 is also formed on the reflecting surface 122A of the elliptical reflector 12, it is possible to prevent the reflectance of the elliptical reflector 12 from being lowered by the photocatalytic reaction, and the light source light emitted from the light source lamp 11 The utilization rate can be further improved.

(1-4) Since the photocatalyst film 111B is formed on the outer peripheral surface of the light emitting unit 111, the organic matter or the like attached to the light emitting unit 111 is decomposed by the photocatalytic reaction, so that the light flux emitted from the inside of the light emitting unit 111 is The light is emitted to the outside without being obstructed by dust and the like, and the light source light can be used without loss even if it is not blown.
(1-5) By including the light source device 10, the projector 1 with improved light utilization can be provided as described above. In addition, the light emitting unit 111, the elliptical reflector 12, and the sub-reflecting mirror 13 are self-cleaned by the photocatalytic function without forcibly cleaning the air by strengthening the fan or by providing a complicated device or the like. Thereby, the space-saving design of the projector 1 is not hindered.

[2] Second Embodiment Next, a second embodiment of the present invention will be described.
In the following description, the same reference numerals are given to the same configurations as those in the embodiment described above, and the description is omitted or simplified.
In the first embodiment, the dielectric multilayer film 60 is deposited on the entire inner peripheral surface 130 of the sub-reflecting mirror 13 to form the reflective surface 131, and is not formed on the outer peripheral surface 132. The light source light was reflected by the reflection surface 131 on the peripheral surface 130 side (FIG. 4).
On the other hand, in the second embodiment, the dielectric multilayer film 90 is formed on the outer peripheral surface 132 of the sub-reflecting mirror 16 to form the reflecting surface 135, and the light source light is reflected by the reflecting surface 135 on the outer peripheral surface 132 side. The point of reflection is different. This will be specifically described below.

FIG. 6 shows the sub-reflecting mirror 16 of the present embodiment. FIG. 7 is an enlarged view of the inner peripheral surface 130 side of the sub-reflecting mirror 16, and FIG. 8 is an enlarged view of the outer peripheral surface 132 side.
The sub-reflecting mirror 16 is made of a translucent material such as YAG (Y ₃ Al ₅ O ₁₂ ) or sapphire, and is substantially the same as the sub-reflecting mirror 13 of the above-described embodiment. 132 is polished into a bowl shape and attached to the light source lamp 11. Here, both sapphire and YAG have high thermal conductivity.
An antireflection film 80 is formed on the inner peripheral surface 130 by vapor deposition. A dielectric multilayer film 90 is deposited on the entire outer peripheral surface 132, and the dielectric multilayer film 90 constitutes a reflective surface 135 of the sub-reflecting mirror 16.

Here, as shown in FIG. 7, the antireflection film 80 is a thin film for preventing reflection of light from the light source, and is formed to include a layer having a photocatalytic function.
First, a tantalum film 81 made of Ta ₂ O ₅ having a high refractive index is formed on the inner peripheral surface 130 of the sub-reflecting mirror 16, and a low refractive index SiO is formed on the tantalum film 81. A silica film 82 of ₂ is laminated. Further, a titanium oxide film 83 made of TiO ₂ having a high refractive index is laminated on the silica film 82, and the titanium oxide film 83 corresponds to a layer having a photocatalytic function. Further, a silica film 82 is laminated on the titanium oxide film 83 to form the outermost layer on the inner surface side of the sub-reflecting mirror 13. As described above, the antireflection film 80 is constituted by, for example, the number of stacked layers of about 2 to 6 layers.
Here, the TiO ₂ contained in the titanium oxide film 83 is anatase TiO ₂ . Anatase type TiO ₂ is larger in crystal than rutile type TiO ₂ , has higher catalytic activity, has a band gap of about 3.2 eV, and has a visible light response such as being activated by light of about 388 nm or less. ing. The band gap of rutile TiO ₂ is about 3.0 eV, and is activated by light of about 413 nm or less.
Further, as shown in FIG. 8, the dielectric multilayer film 90 is made of Ta ₂ O ₅ having a high refractive index, as in the case of the dielectric multilayer film 60 formed on the inner peripheral surface 130 of the embodiment. A tantalum film 91 and a silica film 92 made of SiO ₂ having a low refractive index are alternately laminated to form an increased reflection film. However, in this dielectric multilayer film 90, the titanium oxide film is not laminated.

The antireflection film 80 and the dielectric multilayer film 90 are formed by laminating tantalum films 81 and 91 made of Ta ₂ O ₅ and silica films 82 and 92 made of SiO ₂ , depending on the wavelength of light used. Thus, the antireflection film 80 can be configured by appropriately setting the film thickness so that the phase of the incident light and the reflected light is reversed by the difference in refractive index at the interface between the air, the film, and the substrate. On the contrary, if the film thickness is set so that the phase of the incident light and the reflected light is aligned at the interface, the dielectric multilayer film 90 as the enhanced reflection film can be configured.
Here, the high refractive index layer may be a film made of TiO ₂ , Ta ₂ O ₃ , ZrO ₂ or the like, and the low refractive index layer may be a film made of MgF ₂ , Al ₂ O ₃ or the like. Depending on the wavelength of light emitted from the light source lamp 11, the material, film thickness, stacking order, number of layers, and the like of each of the films 81, 82, 83, 91, 92 are appropriately designed.

The antireflection film 80 and the dielectric multilayer film 90 are formed by vapor deposition, for example, by the following method.
First, the antireflection film 80 is formed. For this, vacuum deposition, sputtering, PVD method such as ion plating described above, etc. is performed, and a tantalum film 81 and a silica film 82 are deposited on the inner peripheral surface 130 base material surface. A chemical vapor deposition (CVD) method such as a liquid phase method / vapor phase method or the like at a relatively high temperature can also be employed.
The titanium oxide film 83 is formed, for example, by the following sol-gel method in order to obtain anatase type TiO ₂ crystal. The raw material of the titanium oxide film 83 is an organic titanium compound centered on an alkoxide, and a solution (sol) containing colloidal oxide precursor particles obtained by hydrolysis in an alcohol medium is heated in a sealed container. Crystallize to fix the membrane. If the heating temperature at this time is set to 500 ° C. to 800 ° C. which is close to the actual use temperature of the projector 1, a titanium oxide film 83 containing a large amount of anatase type TiO ₂ crystals is formed. The temperature when the projector 1 is actually used here refers to the temperature in the vicinity of the inner peripheral surface 130 when the light source lamp 11 emits light. The titanium oxide film 83 thus formed has a small particle size and a uniform particle size, and becomes a hard and dense film. Even if the projector 1 is used at a high temperature, the composition such as the crystal structure is not transformed and the photocatalytic function is not impaired.
Next, a dielectric multilayer film 90 is formed. This is preferably performed, for example, by the above-described ion plating method at a heating temperature of about 300 ° C. to ensure the shape accuracy of the dielectric multilayer film 90 as the reflecting surface 135.

When a light beam is emitted from the inside of the light emitting unit 111, the light beam reaches the titanium oxide film 83 formed in the vicinity of the surface layer of the antireflection film 80 formed on the inner peripheral surface 130 of the sub-reflecting mirror 16, and the sub-reflecting mirror 16 is transmitted through the base material 16 and enters the reflecting surface 135 on the outer peripheral surface 132 side, and is reflected by the elliptical reflector 12 by the reflecting surface 135.
The temperature of the sub-reflecting mirror 16 at this time is, for example, about 100 ° C. lower on the outer peripheral surface 132 than on the inner peripheral surface 130, and the load on the dielectric multilayer film 90 due to high heat is relatively reduced. In addition, since the material of the sub-reflecting mirror 16 has a high thermal conductivity as described above, heat is dissipated and the amount of thermal expansion is suppressed, and peeling of the antireflection film 80 and the dielectric multilayer film 90 is prevented.
Here, the titanium oxide film 83 may contain amorphous having low catalytic activity in addition to the anatase type TiO ₂ , but light is transmitted on the inner peripheral surface 130 side, so that the increase in temperature is mitigated. It is not necessary to transform the amorphous part. In addition, even when rutile crystals are formed, rutile crystals are less likely to transform even at high temperatures, so that catalytic activity can be maintained, and photocatalytic functions can be exerted in response to light in a wide wavelength range. It becomes possible.

Then, by entering the titanium oxide film 83, a photocatalytic reaction is induced, and organic substances in the gap between the sub-reflecting mirror 13 and the light emitting unit 111 are adsorbed and decomposed. Thereby, since dust does not adhere to the reflective surface 135, the light beam from the light emitting unit 111 is emitted to the reflective surface 135 without being blocked by dust.
Furthermore, even if the dew condensation phenomenon occurs, the reflection of light from the sub-reflecting mirror 16 is not hindered by the hydrophilizing action and the organic substance decomposing action.

According to the second embodiment, in addition to the effects described in (1-1) to (1-5) of the first embodiment, there are the following effects.
(2-1) By including anatase TiO _{2 in the} titanium oxide film 83, high catalytic activity can be obtained, the band gap is large, and the semiconductor photocatalytic reaction is activated not only by ultraviolet rays but also by visible light. Therefore, the antifouling effect can be further improved.
(2-2) Since a material having high thermal conductivity is used for the sub-reflecting mirror 16, the sub-reflecting mirror becomes relatively low temperature due to heat radiation, and the amount of thermal expansion is reduced. In addition to prevention, the design of the material and thickness of the film and the degree of freedom of the film forming conditions can be improved.

(2-3) An antireflection film 80 that includes a titanium oxide film 83 and transmits light while preventing reflection is formed on the inner peripheral surface 130 side, and the outer peripheral surface 132 is reflected by the dielectric multilayer film 90. Since the surface 135 is configured, the light flux from the light emitting unit 111 passes through the antireflection film 80 and is reflected by the dielectric multilayer film 90. The organic matter, water droplets, etc. adhering to the gap between the sub-reflecting mirror 16 and the light source lamp 11 are decomposed and hydrophilized by the photocatalytic reaction, so that the translucency from the inner peripheral surface 130 to the outer peripheral surface 132 is maintained. Thus, it is possible to prevent the reflectance of the reflecting surface 135 from being lowered.
Further, since the reflective surface 135 is formed on the outer peripheral surface 132 side, the temperature becomes relatively low, so that the degree of freedom in selecting the material of the dielectric multilayer film 90 can be improved.

(2-4) By arranging the film in which the photocatalytic reaction is induced on the inner peripheral surface 130 side and the reflecting surface 135 on the outer peripheral surface 132 side, the material of the film can be designed according to the application and purpose. . In other words, the outer peripheral surface 132 that is separated from the light source lamp 11 has a lower temperature than the inner peripheral surface 130 side, and a film corresponding to this temperature may be designed.
Further, as in the sol-gel method described above, TiO ₂ is baked at a high temperature to form the titanium oxide film 83, whereby the titanium oxide film 83 containing a lot of anatase type crystal structure can be formed. At this time, since the reflecting surface 135 is disposed on the outer peripheral surface 131 side, the curvature of the reflecting surface 135 can be maintained even if the titanium oxide film 83 is deposited on the inner peripheral surface 130 at a high temperature, and the sub-reflecting mirror 16 is maintained. Does not affect the reflection.
(2-5) Since the titanium oxide film 83 is formed at a temperature close to the actual use conditions of the projector 1, even when exposed to a high temperature of, for example, 300 ° C. or higher during actual use, the titanium oxide film contains a lot of anatase type crystals. 83 crystal structure transformation can be prevented, and photocatalytic performance as expected can be realized.

The present invention is not limited to the above-described embodiments, and includes modifications as described below.
For example, in each of the above embodiments, the titanium oxide films 63, 73, and 83 are coated with the silica films 62, 72, and 82. However, this coating may be omitted. However, in this case, it is preferable to form the film at a high temperature of about 500 ° C. to about 800 ° C. from the viewpoint of stabilization of the crystal structure.
Further, the method of forming the titanium oxide films 63, 73, 83 is not limited to the above embodiments. For example, it is conceivable to improve the band gap by adding an inorganic binder component to form a film.
In addition to the front type projector 1 as described above, the light source device 10 can be used for a rear type projector or the like.
The titanium oxide films 63, 73, and 83 can also be formed on optical components around the light source device 10 such as the explosion-proof glass 14 and the collimated concave lens 15.

  The present invention can be used not only for projectors but also for other small / high brightness illumination devices.

FIG. 2 is a schematic diagram schematically showing the internal structure of the projector according to the first embodiment of the invention. The sectional side view of the light source device in the embodiment. The principal part perspective view of the light source device in the said embodiment. The sectional side view of the sub-reflection mirror in the said embodiment. The figure which represents typically the film of the sub-reflecting mirror in the said embodiment. The sectional side view of the sub-reflection mirror in the said embodiment which concerns on 2nd Embodiment of this invention. The figure which represents typically the film by the side of the internal peripheral surface of the sub-reflection mirror in the said embodiment. The figure which represents typically the film by the side of the outer peripheral surface of the sub-reflecting mirror in the said embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Projector, 10 ... Light source device, 11 ... Light source lamp (arc tube), 12 ... Elliptic reflector (reflector), 13, 15 ... Subreflector, 60, 70, 90 ... Dielectric multilayer, 63, 73 ... Oxidation Titanium film (film having photocatalytic function), 83... Titanium oxide film (translucent and photocatalytic function), 111... Light emitting portion, 111 A... Electrode, 111 B. Membrane), 112... Sealing part, 122 A. Reflecting surface, 130... Inner peripheral surface, 131, 135.

Claims (9)

A light-emitting portion that emits light between electrodes, a light-emitting tube having sealing portions provided at both ends of the light-emitting portion, a reflector that emits light emitted from the light-emitting tube in a certain direction, and a reflecting surface Is a light source device provided with a reflecting surface of the reflector, and a sub-reflecting mirror that covers the front side of the light emission direction of the arc tube and reflects the light beam emitted from the arc tube to the reflector. ,
The reflecting surface of the sub-reflecting mirror is configured as a dielectric multilayer film in which a plurality of films having different refractive indexes are laminated, and a layer having a photocatalytic function is formed in the vicinity of the surface layer of the reflecting surface. A light source device. In the light source device according to claim 1,
The layer having a photocatalytic function is made of anatase type TiO ₂ . The light source device according to claim 1 or 2,
The reflecting surface of the reflector is configured as a dielectric multilayer film in which a plurality of films having different refractive indexes are laminated, and a layer having a photocatalytic function is formed in the vicinity of the surface layer of the reflecting surface. Light source device. In the light source device in any one of Claims 1-3,
The light emitting device is characterized in that a layer having a photocatalytic function is formed on an outer peripheral surface of the light emitting portion. In the light source device according to any one of claims 1 to 4,
The sub-reflecting mirror is made of a material having a thermal conductivity of 10 W / (m · K) or more. A light-emitting portion that emits light between electrodes, a light-emitting tube having sealing portions provided at both ends of the light-emitting portion, a reflector that emits light emitted from the light-emitting tube in a certain direction, and a reflecting surface Is a light source device provided with a reflecting surface of the reflector, and a sub-reflecting mirror that covers the front side of the light emission direction of the arc tube and reflects the light beam emitted from the arc tube to the reflector. ,
The sub-reflecting mirror is made of a translucent material, and a film having translucency and a photocatalytic function is formed on the inner peripheral surface of the sub-reflecting mirror,
The light source device according to claim 1, wherein the reflection surface is configured as the dielectric multilayer film formed on the outer peripheral surface of the sub-reflection mirror. A light source comprising: a light emitting portion that performs discharge light emission between electrodes; a light emitting tube having sealing portions provided at both ends of the light emitting portion; and a sub-reflecting mirror that covers the front side of the light emitting portion of the light emitting portion of the light emitting tube Because
The reflecting surface of the sub-reflecting mirror is configured as a dielectric multilayer film in which a plurality of films having different refractive indexes are laminated,
A light source characterized in that a layer having a photocatalytic function is formed in the vicinity of the surface layer of the reflecting surface. The light source according to claim 7,
The light emitting part is characterized in that a layer having a photocatalytic function is formed on an outer peripheral surface thereof. A projector that modulates a light beam emitted from a light source according to image information to form an optical image, and projects an enlarged image.
A projector comprising the light source device according to any one of claims 1 to 6, or the light source according to any one of claims 7 and 8.

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