JP2007227206A - Light source device and projector - Google Patents

Abstract

A light source device capable of improving the utilization efficiency of light from a tube portion is provided.
A tube bulb 30 containing a pair of electrodes 42, 52 and a pair of sealing portions 40, 50 extending on both sides of the tube bulb 30 are provided, and the tube bulb 30 and the pair of sealing portions 40, 50, the arc tube 20 having a smoothly connected shape, the reflector 10 disposed on the sealing portion 40 side and reflecting the light from the bulb portion 30 toward the illuminated region, and the sealing portion A light source device 110 including a secondary mirror 60 that is disposed on the side of 50 and reflects light from the tube portion 30 toward the tube portion 30. The shape of the inner surface of the secondary mirror 60 is an elliptical shape. The straight line A passing through the inflection point Q existing between the bulb portion 30 and the sealing portion 50 on the outer surface of the arc tube 20 and the intermediate point P between the pair of electrodes 42 and 52, and the illumination optical axis 100ax Assuming that the angle formed is θ and the conic constant of the ellipsoid is K, if θ ≧ 50 degrees, 0 <K <0.5, and if θ <50 degrees, −0.5 < K <0.
[Selection] Figure 3

Description

  The present invention relates to a light source device and a projector.

Conventionally, a light source device including a secondary mirror is known as a light source device used for a projector (see, for example, Patent Document 1). According to the conventional light source device, the light emitted from the arc tube (tube part) to the illuminated area side is reflected toward the reflector by the secondary mirror as the reflecting means. It is possible to effectively use the light that has been emitted and was not used effectively. For this reason, it is possible to further increase the brightness of the projector. Further, it is not necessary to set the size of the reflector so as to cover the end of the arc tube on the illuminated area side, the reflector can be reduced in size, and the projector can be reduced in size. .
JP-A-8-31382 (FIG. 1)

  By the way, in recent years, with the increase in brightness of projectors, the inside of the bulb portion of the arc tube composed of a high-pressure mercury lamp or the like has become a considerably high pressure (for example, 200 atmospheres or more). For this reason, in the arc tube, in order to withstand this atmospheric pressure, the thickness of the tube portion is increased and a seal method called a shrink seal is employed. As a result, it is possible to increase the output of the arc tube.

  However, the conventional light source device has a problem that the utilization efficiency of light from the bulb portion is reduced.

  Therefore, the present invention has been made to solve such a problem, and an object thereof is to provide a light source device capable of improving the utilization efficiency of light from a tube portion. It is another object of the present invention to provide a projector with high brightness provided with such a light source device.

  In order to achieve the above object, the inventor of the present invention has made extensive efforts to find out the cause of the decrease in the light use efficiency from the tube portion in the conventional light source device. The light that is emitted from the center position (intermediate point of the pair of electrodes) toward the illuminated area, reflected by the inner surface of the secondary mirror, and re-entered the tube section does not go to the center position of the tube section. I got the knowledge that there is a shift to the reflector side.

  FIG. 5 is a diagram for explaining a problem in the conventional light source device. FIG. 5A is a view for explaining a conventional light source device 900, and FIG. 5B schematically shows a locus of light L emitted from the tube portion 930 toward the illuminated area. FIG.

  As shown in FIG. 5A, a conventional light source device 900 includes a tube portion 930 containing a pair of electrodes 942 and 952 arranged along an illumination optical axis 900ax and a pair extending on both sides of the tube portion 930. The arc tube 920 having the sealing portions 940 and 950, the reflector 910 which is disposed on the one sealing portion 940 side and reflects the light from the bulb portion 930 toward the illuminated area, and the other sealing portion. The light source device includes a secondary mirror 960 that is disposed on the stop portion 950 side and reflects light from the bulb portion 930 toward the bulb portion 930.

  The tube portion 930 is configured such that the thickness of the portion far from the attachment site of the electrodes 942 and 952 is larger than the thickness of the portion that is close. In addition, the center position of the tube portion 930 (the intermediate point P between the pair of electrodes 942 and 952) and the focal position of the reflector 910 (if the reflector 910 is an ellipsoidal reflector, the first focal position of the ellipsoidal reflector, the parabola In the case of a surface reflector, the reflector 910 and the arc tube 920 are arranged so that the focal position of the paraboloidal reflector substantially coincides. The sub mirror 960 is configured such that the inner surface thereof is a spherical surface.

  In the conventional light source device 900, the light L emitted from the center position of the bulb portion 930 toward the illuminated region side (the other sealing portion 950 side) is reflected by the inner surface of the secondary mirror 960 and is again a tube. When entering into the sphere 930, due to the lens effect or spherical aberration of the so-called tube portion 930, as shown in FIG. It will shift to the part 940 side. Therefore, the light L described above is in the vicinity of the focal point of the reflector 910 (in the case where the reflector 910 is an elliptical reflector, in the vicinity of the first focal point of the elliptical reflector, in the case of the parabolic reflector, in the vicinity of the focal point of the parabolic reflector). ), The quality of light emitted from the reflector 910 is deteriorated (condensation is reduced when the reflector 910 is an ellipsoidal reflector, and parallelism when the reflector 910 is a parabolic reflector). Decreases.) As a result, the amount of illumination light that can be used on the illuminated area side is reduced, and the utilization efficiency of light from the tube portion 930 is reduced.

  By the way, since the outer surface shape of the bulb portion in the arc tube is various, there are various paths along which the light reflected by the inner surface of the secondary mirror and incident again into the bulb portion can be changed. In this case, it is considered that it is not easy to determine whether the light reflected by the inner surface of the secondary mirror and incident again into the tube portion is directed to the center position of the tube portion.

  However, according to the present inventors' investigation, the shape of the inner surface of the secondary mirror is an elliptical shape, and the inflection point existing on the outer surface of the bulb portion and the intermediate point between the pair of electrodes (that is, the bulb portion) The cone coefficient of the ellipsoid is set to an appropriate range when the angle θ formed by the straight line passing through the center position of the light source and the illumination optical axis is 50 degrees or more and when the angle θ is less than 50 degrees. As a result, it has been found that the light reflected by the inner surface of the secondary mirror and incident again into the tube portion is directed toward the center position of the tube portion.

  Therefore, the inventor of the present invention makes the shape of the inner surface of the secondary mirror an elliptical shape based on the above knowledge, and passes through the inflection point existing on the outer surface of the tube portion and the intermediate point of the pair of electrodes. When the angle θ between the straight line and the illumination optical axis is 50 degrees or more and when the angle θ is less than 50 degrees, the conic constant of the ellipsoid is set to an appropriate range, respectively. The light reflected from the inner surface of the mirror and incident on the tube part again comes to the center of the tube part, and as a result, the light use efficiency from the tube part can be improved. The present invention has been completed.

  The light source device according to the present invention includes a tube bulb portion including a pair of electrodes arranged along an illumination optical axis, and a pair of sealing portions extending on both sides of the tube bulb portion. An arc tube having a shape in which the sealing portion of the arc tube is smoothly connected to one of the sealing portions of the arc tube, and reflects light from the bulb portion toward the illuminated area. In a light source device comprising a reflector and a secondary mirror disposed on the other sealing portion side of the arc tube and reflecting light from the bulb portion toward the bulb portion, an inner surface of the secondary mirror is provided. The shape is an elliptical shape, a straight line passing through an inflection point existing between the bulb portion and the other sealing portion on the outer surface of the arc tube, and an intermediate point between the pair of electrodes, When θ is the angle between the illumination optical axis and K is the conic constant of the ellipsoid, , 0 <K <0.5, and when θ <50 degrees, −0.5 <K <0.

For this reason, according to the light source device of the present invention, the shape of the inner surface of the secondary mirror is an ellipsoidal shape, and an inflection point existing on the outer surface of the bulb portion and a straight line passing through the intermediate point of the pair of electrodes and illumination By setting the cone coefficient of the ellipsoid to be in the above range when the angle θ formed with the optical axis is 50 degrees or more and when the angle is less than 50 degrees, The light that has been reflected and entered the tube portion again travels toward the center of the tube portion. As a result, it is possible to suppress a decrease in the quality of light emitted from the reflector, and it is possible to suppress a decrease in the amount of illumination light that can be used on the illuminated area side.
Therefore, the light source device of the present invention is a light source device capable of improving the utilization efficiency of light from the bulb portion.

  In the light source device of the present invention, when θ ≧ 50 degrees, 0.1 <K <0.3, and when θ <50 degrees, −0.3 <K <−0.1. Preferably there is.

  By configuring in this way, it becomes possible to make the shape of the inner surface of the secondary mirror more suitable for the shape of the outer surface of the tube portion, thereby further improving the utilization efficiency of light from the tube portion. Is possible.

  In the light source device of the present invention, the reflector can be an ellipsoidal reflector or a parabolic reflector.

  According to the light source device of the present invention, it is possible to improve the utilization efficiency of the light from the tube portion even when any type of reflector is used.

  The projector of the present invention includes an illuminating device having a light source device that emits an illuminating light beam toward the illuminated region, an electro-optic modulator that modulates the illuminating light beam from the illuminating device according to image information, and the electro-optic modulator. And a projection optical system that projects the light modulated by the light source device, wherein the light source device is the light source device of the present invention.

  For this reason, as described above, the projector according to the present invention includes an excellent light source device capable of improving the utilization efficiency of light from the bulb portion, and thus becomes a projector with higher brightness than in the past.

  Hereinafter, a light source device and a projector according to the present invention will be described based on embodiments shown in the drawings.

[Embodiment 1]
FIG. 1 is a diagram illustrating an optical system of a projector 1000 according to the first embodiment. 2 and 3 are views for explaining the light source device 110 according to the first embodiment. 3A is an enlarged view of a main part of the light source device 110, and FIG. 3B is a diagram schematically showing a trajectory of light emitted from the center position of the tube portion 30 toward the illuminated area. It is.

  In the following description, three directions orthogonal to each other are defined as a z-axis direction (illumination optical axis 100ax direction in FIG. 1), an x-axis direction (a direction parallel to the paper surface in FIG. 1 and perpendicular to the z-axis), and y. An axial direction (a direction perpendicular to the paper surface in FIG. 1 and perpendicular to the z-axis).

  As shown in FIG. 1, the projector 1000 according to the first embodiment separates the illumination device 100 and the illumination light flux from the illumination device 100 into three color lights of red light, green light, and blue light and guides them to the illumination area. The three color liquid crystal devices 400R, 400G, and 400B as electro-optic modulation devices that modulate the light-separated color separation light guide optical system 200 and the three color lights separated by the color separation light guide optical system 200 according to image information. A cross dichroic prism 500 that combines the color lights modulated by the three liquid crystal devices 400R, 400G, and 400B, and a projection optical system 600 that projects the light combined by the cross dichroic prism 500 onto a projection surface such as a screen SCR. It is a projector provided with.

  The illuminating device 100 includes a light source device 110 that emits an illumination light beam toward the illuminated region, a concave lens 90 that emits the focused light from the light source device 110 as substantially parallel light, and a plurality of portions of the illumination light beam emitted from the concave lens 90. A first lens array 120 having a plurality of first small lenses 122 for dividing the light beam, and a second lens having a plurality of second small lenses 132 corresponding to the plurality of first small lenses 122 of the first lens array 120. Array 130, polarization conversion element 140 that converts each partial light beam from second lens array 130 into substantially one type of linearly polarized light having the same polarization direction and emits the light, and each partial light beam emitted from polarization conversion element 140 And a superimposing lens 150 for superimposing the image on the illuminated area.

  As shown in FIGS. 1 and 2, the light source device 110 according to the first embodiment includes an ellipsoidal reflector 10 as a reflector, an arc tube 20 having a light emission center near the first focal point of the ellipsoidal reflector 10, and reflecting means. As a secondary mirror 60. The light source device 110 emits a light beam having the illumination optical axis 100ax as a central axis.

  As shown in FIG. 2, the arc tube 20 includes a tube bulb 30 containing a pair of electrodes 42 and 52 arranged along the illumination optical axis 100ax, and a pair of sealing portions extending on both sides of the tube bulb 30. 40, 50, a pair of metal foils 44, 54 sealed in the pair of sealing portions 40, 50, respectively, and a pair of lead wires 46, electrically connected to the pair of metal foils 44, 54, respectively. 56. And the outer surface of the tube part 30 and the outer surface of a pair of sealing parts 40 and 50 are connected smoothly.

  The outer surface of the tube portion 30 and the outer surfaces of the pair of sealing portions 40 and 50 are smoothly connected. As shown in FIG. 3A, an inflection point Q exists between the bulb portion 30 and the sealing portion 50 on the outer surface of the arc tube 20. The arc tube 20 used in the light source device 110 according to the first embodiment, where θ is an angle formed by the straight line A passing through the inflection point Q and the intermediate point P between the pair of electrodes 42 and 52 and the illumination optical axis 100ax. In this case, θ = 55 degrees.

In addition, if the conditions of the components of the arc tube 20 are exemplarily shown, the tube portion 30 and the sealing portions 40 and 50 are made of, for example, quartz glass, and the tube portion 30 has mercury or a rare gas. And a small amount of halogen is enclosed. The electrodes 42 and 52 are, for example, tungsten electrodes, and the metal foils 44, 54 are, for example, molybdenum foils. The lead wires 46 and 56 are made of, for example, molybdenum or tungsten.
Further, as the arc tube 20, various arc tubes that emit light with high luminance can be employed, for example, a high pressure mercury lamp, an ultra high pressure mercury lamp, a metal halide lamp, or the like.

  As shown in FIG. 2, the ellipsoidal reflector 10 includes an opening 12 for inserting and fixing the sealing portion (one sealing portion) 40 of the arc tube 20, and light emitted from the arc tube 20 in the first position. And a reflective concave surface 14 that reflects toward the two focal positions. The ellipsoidal reflector 10 is fixed to the sealing portion 40 of the arc tube 20 with an inorganic adhesive C such as cement filled in the opening 12 of the ellipsoidal reflector 10.

For example, crystallized glass, alumina (Al ₂ O ₃ ), or the like can be suitably used as the material for the base material constituting the reflective concave surface 14. On the inner surface of the reflective concave surface 14, for example, a visible light reflecting layer made of a dielectric multilayer film of titanium oxide (TiO ₂ ) and silicon oxide (SiO ₂ ) is formed.

  As shown in FIGS. 2 and 3, the secondary mirror 60 includes an opening 62 for inserting and fixing to the sealing portion (the other sealing portion) 50 of the arc tube 20, and the illuminated region side from the arc tube 20. And a reflecting concave surface 64 that reflects the light emitted toward the arc tube 20 toward the arc tube 20. The light reflected by the secondary mirror 60 passes through the arc tube 20 and enters the ellipsoidal reflector 10. The secondary mirror 60 is fixed to the sealing portion 50 of the arc tube 20 with an inorganic adhesive C such as cement filled in the opening 62 of the secondary mirror 60.

As a material constituting the reflective concave surface 64, for example, translucent alumina is used. Thereby, the heat dissipation in the secondary mirror 60 can be improved. In addition to alumina, materials such as quartz glass, sapphire, and ruby may be used.
On the inner surface of the reflective concave surface 64, for example, a reflective layer made of a dielectric multilayer film of tantalum oxide (Ta ₂ O ₅ ) and silicon oxide (SiO ₂ ) is formed.

  The shape of the inner surface of the secondary mirror 60 is an elliptical shape. When the conical constant of the ellipsoid is K, in the secondary mirror 60 used in the light source device 110 according to Embodiment 1, K = 0.2 is set.

  As shown in FIG. 1, the concave lens 90 is disposed on the illuminated area side of the ellipsoidal reflector 10. The light from the ellipsoidal reflector 10 is emitted toward the first lens array 120.

  The first lens array 120 has a function as a light beam splitting optical element that splits light from the concave lens 90 into a plurality of partial light beams, and a plurality of first lens arrays 120 arranged in a matrix in a plane orthogonal to the illumination optical axis 100ax. It has a configuration provided with one small lens 122. Although not illustrated, the outer shape of the first small lens 122 is similar to the outer shape of the image forming area of the liquid crystal devices 400R, 400G, and 400B.

  The second lens array 130 is an optical element that collects a plurality of partial light beams divided by the first lens array 120 described above, and in the same manner as the first lens array 120, a matrix is formed in a plane orthogonal to the illumination optical axis 100ax. And a plurality of second small lenses 132 arranged in a shape.

The polarization conversion element 140 is a polarization conversion element that emits the polarization direction of each partial light beam divided by the first lens array 120 as approximately one type of linearly polarized light having a uniform polarization direction.
The polarization conversion element 140 transmits one linear polarization component of the polarization component included in the illumination light beam from the light source device 110 as it is, and reflects the other linear polarization component in a direction perpendicular to the illumination optical axis 100ax. And the other linearly polarized light component reflected by the polarization separation layer in a direction parallel to the illumination optical axis 100ax, and the other linearly polarized light component reflected by the reflective layer is converted into one linearly polarized light component. And a retardation plate.

  The superimposing lens 150 condenses a plurality of partial light beams that have passed through the first lens array 120, the second lens array 130, and the polarization conversion element 140, and superimposes them on the vicinity of the image forming regions of the liquid crystal devices 400R, 400G, and 400B. It is an element. The superimposing lens 150 shown in FIG. 1 is composed of a single lens, but may be composed of a compound lens in which a plurality of lenses are combined.

  As shown in FIG. 1, the color separation light guide optical system 200 includes dichroic mirrors 210 and 220, reflection mirrors 230, 240 and 250, and relay lenses 260 and 270. The color separation light guide optical system 200 separates the illumination light beam emitted from the illumination device 100 into three color lights of red light, green light, and blue light, and the respective color lights are liquid crystal devices 400R, 400G, and 400 to be illuminated. It has a function of leading to 400B.

  The dichroic mirrors 210 and 220 are optical elements on which a wavelength selection film that reflects a light beam in a predetermined wavelength region and transmits a light beam in another wavelength region is formed on a substrate. The dichroic mirror 210 disposed in the front stage of the optical path is a mirror that reflects a red light component and transmits other color light components. The dichroic mirror 220 disposed in the latter stage of the optical path is a mirror that reflects the green light component and transmits the blue light component.

  The red light component reflected by the dichroic mirror 210 is bent by the reflection mirror 230 and enters the image forming area of the liquid crystal device 400R for red light through the condenser lens 300R.

  The condenser lens 300R is provided to convert each partial light beam from the superimposing lens 150 into a light beam substantially parallel to each principal ray. The condensing lenses 300G and 300B disposed in the preceding stage of the optical path of the other liquid crystal devices 400G and 400B are configured in the same manner as the condensing lens 300R.

  Of the green light component and the blue light component that have passed through the dichroic mirror 210, the green light component is reflected by the dichroic mirror 220, passes through the condenser lens 300G, and enters the image forming region of the green light liquid crystal device 400G. On the other hand, the blue light component is transmitted through the dichroic mirror 220, passes through the incident side lens 260, the incident side reflection mirror 240, the relay lens 270, the emission side reflection mirror 250, and the condensing lens 300B, and is a liquid crystal for blue light. The light enters the image forming area of the apparatus 400B. The incident side lens 260, the relay lens 270, and the reflection mirrors 240 and 250 have a function of guiding the blue light component transmitted through the dichroic mirror 220 to the liquid crystal device 400B.

  The reason that the incident side lens 260, the relay lens 270, and the reflection mirrors 240 and 250 are provided in the optical path of blue light is that the length of the optical path of blue light is longer than the length of the optical paths of other color lights. For this reason, a decrease in light use efficiency due to light divergence or the like is prevented. The projector 1000 according to Embodiment 1 has such a configuration because the length of the optical path of blue light is long. However, the length of the optical path of red light is increased, and the incident side lens 260 and the relay lens 270 are configured. And the structure which uses the reflective mirrors 240 and 250 for the optical path of red light is also considered.

The liquid crystal devices 400 </ b> R, 400 </ b> G, and 400 </ b> B modulate the incident illumination light beam according to image information, and are the illumination target of the illumination device 100. Although not shown, incident side polarizing plates are arranged between the condenser lenses 300R, 300G, and 300B and the liquid crystal devices 400R, 400G, and 400B, respectively, and the liquid crystal devices 400R, 400G, and 400B, Between the cross dichroic prism 500, an exit-side polarizing plate is disposed. The incident-side polarizing plate, the liquid crystal devices 400R, 400G, and 400B and the exit-side polarizing plate modulate light of each incident color light.
The liquid crystal devices 400R, 400G, and 400B are a pair of transparent glass substrates in which a liquid crystal that is an electro-optical material is hermetically sealed. For example, a polysilicon TFT is used as a switching element and incident according to a given image signal. Modulates the polarization direction of one type of linearly polarized light emitted from the side polarizing plate.

  The cross dichroic prism 500 is an optical element that forms a color image by synthesizing an optical image modulated for each color light emitted from the emission side polarizing plate. The cross dichroic prism 500 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 a substantially X-shaped interface in which the right-angle prisms are bonded together. The dielectric multilayer film formed at one of the substantially X-shaped interfaces reflects red light, and the dielectric multilayer film formed at the other interface reflects blue light. By these dielectric multilayer films, the red light and the blue light are 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 500 is enlarged and projected by the projection optical system 600 to form a large screen image on the screen SCR.

  As described above, the light source device 110 according to the first embodiment includes the tube portion 30 and the pair of sealing portions 40 and 50 as described above, and includes the tube portion 30 and the pair of sealing portions 40 and 50. Arc tube 20 having a smoothly connected shape, and an elliptical reflector that is disposed on one sealing portion 40 side of the arc tube 20 and reflects light from the bulb portion 30 toward the illuminated region. 10 and a secondary mirror 60 that is disposed on the other sealing portion 50 side of the arc tube 20 and reflects light from the tube bulb 30 toward the bulb 30. The shape of the inner surface of the secondary mirror 60 is an elliptical shape. Further, the angle θ formed by the straight line A shown in FIG. 3A and the illumination optical axis 100ax is θ = 55 degrees, and the conical constant K of the elliptical surface for determining the inner surface of the secondary mirror 60 is K = It is set to 0.2.

For this reason, according to the light source device 110 according to the first embodiment, the shape of the inner surface of the sub-mirror 60 is an elliptical shape, the inflection point Q existing on the outer surface of the tube portion 30 and the pair of electrodes 42, When the angle θ formed by the straight line A passing through the intermediate point P of 52 and the illumination optical axis 100ax is 50 degrees or more, the conical coefficient K of the ellipsoid is set to 0 <K <0.5. As shown in FIG. 3B, the light L reflected by the inner surface of the secondary mirror 60 and entering the tube portion 30 again is directed toward the center position of the tube portion 30. Thereby, since the light L passes through the vicinity of the first focal point of the ellipsoidal reflector 10, it is possible to suppress a decrease in the condensing property of the light emitted from the ellipsoidal reflector 10. As a result, it is possible to suppress a decrease in the amount of illumination light available on the illuminated area side. When the above-mentioned angle θ is 50 degrees or more and the conic constant K of the elliptical surface is set to 0.1 <K <0.3, the shape of the inner surface of the secondary mirror is changed to the shape of the outer surface of the tube portion 30. Therefore, it is possible to further improve the utilization efficiency of light from the tube portion 30.
Therefore, the light source device 110 according to the first embodiment is a light source device capable of improving the utilization efficiency of light from the tube portion 30.

  As described above, the projector 1000 according to the first embodiment includes the excellent light source device 110 that can improve the utilization efficiency of the light from the tube section 30, and thus becomes a projector with higher brightness than the conventional one. .

[Embodiment 2]
FIG. 4 is a diagram for explaining the light source device 110A according to the second embodiment. 4A is an enlarged view of a main part of the light source device 110A, and FIG. 4B is a diagram schematically showing a locus of light emitted from the central position of the tube portion 30A toward the illuminated area. It is. 4, the same members as those in FIG. 3 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The light source device 110A according to the second embodiment basically has a configuration similar to that of the light source device 110 according to the first embodiment. However, as shown in FIG. The light source device 110 is different from the light source device 110 according to the first embodiment in that the shape of the inner surface of the mirror is different.

  That is, in the light source device 110A according to the second embodiment, the shape of the outer surface of the tube portion 30A is such that the straight line A passing through the inflection point Q and the intermediate point P between the pair of electrodes 42A and 52A, and the illumination optical axis 100ax. The outer surface shape is such that θ = 45 degrees, where θ is the angle formed by. The shape of the inner surface of the secondary mirror 60A is an elliptical shape, and the conic constant K of the elliptical surface is set to K = −0.2.

  As described above, the light source device 110A according to the second embodiment differs from the light source device 110 according to the first embodiment in the shape of the outer surface of the tube portion and the shape of the inner surface of the secondary mirror, but the light source device according to the first embodiment. As in the case of 110, the arc tube 20A has a tube portion 30A and a pair of sealing portions 40A, 50A, and the tube portion 30A and the pair of sealing portions 40A, 50A are smoothly connected. And an ellipsoidal reflector 10A (not shown) that is disposed on the sealing portion 40A side and reflects light from the tube portion 30A toward the illuminated area, and is disposed on the sealing portion 50A side. The light source device includes a secondary mirror 60A that reflects light from the tube portion 30A toward the tube portion 30A. In the light source device 110A according to the second embodiment, the angle θ formed by the straight line A and the illumination optical axis 100ax shown in FIG. 4A is θ = 45 degrees, and the inner surface of the secondary mirror 60A is determined. The conic constant K of the ellipsoidal surface is set to K = −0.2.

Therefore, according to the light source device 110A according to the second embodiment, the shape of the inner surface of the secondary mirror 60A is an elliptical shape, the inflection point Q and the pair of electrodes 42A, which are present on the outer surface of the tube portion 30A, When the angle θ formed by the straight line A passing through the intermediate point P of 52A and the illumination optical axis 100ax is less than 50 degrees, the conic coefficient K of the ellipsoid is set to −0.5 <K <0. As shown in FIG. 4B, the light L reflected by the inner surface of the secondary mirror 60A and incident again into the tube portion 30A is directed toward the center position of the tube portion 30A. Thereby, since the light L passes through the vicinity of the first focal point of the ellipsoidal reflector 10A, it is possible to suppress a decrease in the light condensing property of the light emitted from the ellipsoidal reflector 10A. As a result, it is possible to suppress a decrease in the amount of illumination light available on the illuminated area side. When the above-mentioned angle θ is less than 50 degrees and the conic constant K of the elliptical surface is set to −0.3 <K <−0.1, the shape of the inner surface of the secondary mirror is changed to the outer surface of the tube portion 30A. Therefore, it is possible to further improve the utilization efficiency of light from the tube portion 30A.
Accordingly, the light source device 110A according to the second embodiment is a light source device capable of improving the utilization efficiency of light from the tube portion 30A, as in the case of the light source device 110 according to the first embodiment.

  Although the light source device and the projector of the present invention have been described based on the above embodiments, the present invention is not limited to the above embodiments, and can be implemented in various modes without departing from the scope of the invention. For example, the following modifications are possible.

(1) Although the light source devices 110 and 110A of the above embodiments use an elliptical reflector as a reflector, the present invention is not limited to this, and a parabolic reflector can also be preferably used.

(2) In the projector 1000 according to the first embodiment, the lens integrator optical system including the first lens array 120 and the second lens array 130 is used as the light uniformizing optical system. However, the present invention is not limited to this. A rod integrator optical system including a light guide rod can also be preferably used.

(3) The projector 1000 according to the first embodiment is a transmissive projector, but the present invention is not limited to this. The present invention can also be applied to a reflection type projector. Here, “transmission type” means that an electro-optic modulation device as a light modulation means, such as a transmission type liquid crystal device, transmits light, and “reflection type” This means that an electro-optic modulation device as a light modulation means, such as a reflective liquid crystal device, is a type that reflects light. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

(4) In the above embodiment, the projector using the three liquid crystal devices 400R, 400G, and 400B has been described as an example. However, the present invention is not limited to this, and one, two, or four or more projectors are used. The present invention can also be applied to a projector using such a liquid crystal device.

(5) Although the projector 1000 according to the first embodiment uses a liquid crystal device as an electro-optic modulation device, the present invention is not limited to this. In general, the electro-optic modulation device may be any device that modulates incident light in accordance with image information, and a micromirror light modulation device or the like may be used. For example, a DMD (digital micromirror device) (trademark of TI) can be used as the micromirror light modulator.

(6) The present invention can be applied to a front projection type projector that projects from the side that observes the projected image, and also to a rear projection type projector that projects from the side opposite to the side that observes the projected image. Is also possible.

FIG. 3 shows an optical system of the projector 1000 according to the first embodiment. The figure shown in order to demonstrate the light source device 110 which concerns on Embodiment 1. FIG. The figure shown in order to demonstrate the light source device 110 which concerns on Embodiment 1. FIG. The figure shown in order to demonstrate 110 A of light source devices which concern on Embodiment 2. FIG. The figure shown in order to demonstrate the problem in the conventional light source device 900. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Ellipsoidal reflector, 12,912 ... Opening part, 14,914 ... Reflection concave surface, 20, 20A, 920 ... Arc tube, 30, 30A, 930 ... Tube part, 40, 40A, 50, 50A, 940, 950 ... Sealing part, 42, 42A, 52, 52A, 942, 952 ... Electrode, 44, 44A, 54, 54A, 944, 954 ... Metal foil, 46, 56, 946, 956 ... Lead wire, 60, 60A, 960 ... secondary mirror, 62, 62A, 962 ... opening, 64, 64A, 964 ... reflective concave surface, 90 ... concave lens, 100 ... illumination device, 100ax, 900ax ... illumination optical axis, 110, 110A, 900 ... light source device, 120 ... 1st lens array 122 ... 1st small lens 130 ... 2nd lens array 132 ... 2nd small lens 140 ... Polarization conversion element 150 ... Superposition lens 200 ... Color Light guiding optical system, 210, 220 ... Dichroic mirror, 230, 240, 250 ... Reflecting mirror, 260 ... Incident side lens, 270 ... Relay lens, 300R, 300G, 300B ... Condensing lens, 400R, 400G, 400B ... Liquid crystal device , 500 ... Cross dichroic prism, 600 ... Projection optical system, 910 ... Reflector, 1000 ... Projector, A ... Straight line passing through the inflection point Q and the intermediate point P between the pair of electrodes, C ... Inorganic adhesive, L ... Light , P: intermediate point of the pair of electrodes, Q: inflection point, θ: angle formed by the straight line A and the illumination optical axis, SCR: screen

Claims (4)

A tube bulb portion including a pair of electrodes disposed along the illumination optical axis, and a pair of sealing portions extending on both sides of the tube bulb portion, and the tube bulb portion and the pair of seal portions are smooth An arc tube having a shape connected to,
A reflector that is disposed on one sealing portion side of the arc tube and reflects light from the bulb portion toward the illuminated region; and
In the light source device provided with a secondary mirror disposed on the other sealing portion side of the arc tube and reflecting light from the bulb portion toward the bulb portion,
The shape of the inner surface of the secondary mirror is an elliptical shape,
The angle between the illumination optical axis and a straight line passing through an inflection point existing between the bulb portion and the other sealing portion on the outer surface of the arc tube and the intermediate point of the pair of electrodes is defined as θ. ,
When the elliptical cone constant is K,
When θ ≧ 50 degrees, 0 <K <0.5,
In the case of θ <50 degrees, the light source device is characterized in that −0.5 <K <0. The light source device according to claim 1,
In the case of θ ≧ 50 degrees, 0.1 <K <0.3,
In the case of θ <50 degrees, the light source device is characterized in that −0.3 <K <−0.1. The light source device according to claim 1 or 2,
The light source device, wherein the reflector is an ellipsoidal reflector or a parabolic reflector. An illuminating device having a light source device that emits an illuminating light beam toward the illuminated region;
An electro-optic modulation device that modulates illumination light flux from the illumination device according to image information;
In a projector including a projection optical system that projects light modulated by the electro-optic modulation device,
The projector according to claim 1, wherein the light source device is the light source device according to claim 1.

Images