JP2010129504A - Luminous tube, light source device and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a luminous tube capable of achieving a longer life and higher brightness even when the temperature of an upper region in an internal surface of a tube portion tends to rise and even when the temperature of a lower region in the internal surface of the tube portion tends to rise. <P>SOLUTION: The luminous tube satisfies (L<SB>C</SB>-L<SB>A</SB>)=(L<SB>D</SB>-L<SB>B</SB>) and L<SB>A</SB>≠L<SB>B</SB>assuming that an intermediate position between a pair of electrodes 42, 52 is a point P, the lowermost position relative to gravity in the internal surface of a tube unit 30 is a point A and the uppermost position is a point B, the lowermost position relative to gravity in an external surface of the tube unit 20 is a point C and the uppermost position is a point D, a distance from the point P to the point A is L<SB>A</SB>, a distance from the point P to the point B is L<SB>B</SB>, a distance from the point P to the point C is L<SB>C</SB>, and a distance from the point P to a point D is L<SB>D</SB>. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an arc tube, a light source device, and a projector.

  2. Description of the Related Art Conventionally, as an arc tube for a light source device of a projector, an arc tube including a tube bulb portion including a pair of electrodes and a pair of sealing portions extending on both sides of the bulb portion is known (for example, Patent Documents). 1).

JP 2005-5183 A

  By the way, in the conventional arc tube, the temperature of the upper region with respect to the gravity on the inner surface of the bulb portion is likely to be particularly high due to thermal convection, and the temperature exceeds the allowable temperature of the base material constituting the bulb portion. In this case, local swelling may occur or whitening may occur in the upper region of the outer surface of the tube portion. Whitening is a phenomenon in which the base material constituting the tube portion becomes clouded and devitrified. When local swelling occurs in the bulb portion, the arc tube may rupture due to a decrease in strength. Further, when the tube bulb portion is whitened, light transmission is hindered at the whitened portion, and as a result, heat is generated and the temperature of the arc tube further rises. As a result, the arc tube may burst. .

  In order to suppress the temperature rise in the upper region on the inner surface of the tube portion, it is conceivable to cool the arc tube with a cooling mechanism. However, in the conventional arc tube, as described above, the temperature of the upper region on the inner surface of the tube portion is likely to increase due to thermal convection, and the temperature of the upper region and the lower region on the inner surface of the tube portion. Therefore, when the tube part is cooled to cool the temperature of the upper region on the inner surface of the tube part to a predetermined temperature or lower, the temperature difference between the outer surface and the inner surface of the tube part is The lower region is cooled more than necessary, and the lower region on the inner surface of the tube portion may be blackened. Blackening means that the evaporating performance of the encapsulated material (eg, mercury, rare gas, metal halide, etc.) enclosed in the tube part is reduced, and the efficiency of the halogen cycle is reduced. It is a phenomenon that adheres to the inner wall of the part. When the tube portion is blackened in this way, light is absorbed at the blackened portion, so that the light quantity of the arc tube may be reduced or the arc tube may be damaged.

  As described above, generally, the temperature of the upper region on the inner surface of the tube portion tends to increase, but conversely, for example, the temperature of the upper region on the inner surface of the tube portion is cooled to a predetermined temperature or lower. If the upper region of the tube portion is cooled more strongly, the temperature of the lower region on the inner surface of the tube portion may increase.

  Therefore, the present invention has been made to solve the above-described problem, and the temperature of the upper region on the inner surface of the tube portion is likely to be high and the temperature of the lower region on the inner surface of the tube portion is high. It is an object of the present invention to provide an arc tube capable of further increasing the brightness while extending the life in any case. It is another object of the present invention to provide a light source device and a projector provided with such an excellent arc tube.

  As a result of intensive studies to solve the above problems, the present inventor has found that the distance from the middle position between the pair of electrodes to the position on the innermost surface of the tube portion that is the uppermost side with respect to the gravity, The distance from the intermediate position to the lowest position with respect to gravity on the inner surface of the tube part is determined by the temperature of the upper region on the inner surface of the tube part and the temperature of the lower region on the inner surface of the tube part. If it is adjusted according to the situation, which is higher, the temperature rise in the upper region and the lower region on the inner surface of the tube portion can be suppressed, and the temperature of the upper region on the inner surface of the tube portion can be reduced. The temperature difference with the temperature of the lower region can be reduced, and as a result, it is possible to achieve a further increase in brightness while extending the life, and the present invention has been completed. It was.

That is, the arc tube of the present invention is an arc tube having a tube bulb portion incorporating a pair of electrodes, and a pair of sealing portions extending on both sides of the tube bulb portion, the shaft of the pair of seal portions A point P that is an intermediate position of the pair of electrodes in a cross section when the arc tube is cut in a virtual plane along the direction of gravity, and is the lowest position with respect to gravity on the inner surface of the tube portion Is the point A, the position that is the uppermost side with respect to the gravity on the inner surface of the tube part is the point B, the position that is the lowermost side with respect to the gravity on the outer surface of the tube part is the point C, and the tube the uppermost a position with respect to gravity in the outer surface of the bulb to a point D, and the distance from the point P to the point a and L _a, the distance from the point P to the point B and L _B, the point from the point P C the distance to the L _C, and the distance from the point P to the point D was L _D, "(L _{C L A) = (L D -L} B) "and is characterized by satisfying the relation of" _{L A} ≠ _{L B} ".

For this reason, according to the arc tube of the present invention, the thickness of the upper side and the lower side of the bulb part is the same (“(L _C −L _A ) = (L _D −L _B )”). The distance between the middle position (P) of the pair of electrodes at the center and the upper region on the inner surface of the tube portion, and the distance between the middle position (P) of the pair of electrodes and the lower region on the inner surface of the tube portion Is adjusted so as to satisfy the relationship of “L _A ≠ L _B ”, the temperature rise in the upper region and the lower region on the inner surface of the tube portion can be suppressed, and the tube portion The temperature difference between the temperature of the upper region and the temperature of the lower region on the inner surface can be reduced, and as a result, it is possible to further increase the brightness while extending the life.

In the arc tube of the present invention, it is preferable to satisfy the relationship “L _A <L _B ”.

  With this configuration, when the temperature of the upper region on the inner surface of the bulb portion is likely to be high, the intermediate position (P) of the pair of electrodes serving as the center of the heat source and the upper position on the inner surface of the bulb portion The distance to the region is longer than the distance between the intermediate position (P) of the pair of electrodes and the lower region on the inner surface of the bulb portion. In other words, the upper region on the inner surface of the tube portion where the temperature is likely to rise due to heat convection and the like can be separated from the heat source to some extent, so that the temperature increase of the upper region on the inner surface of the tube portion is suppressed, The temperature difference between the temperature of the upper region and the temperature of the lower region on the inner surface of the tube portion can be reduced, and as a result, it is possible to further increase the brightness while extending the life. .

In the arc tube of the present invention, it is preferable to satisfy the relationship of “L _A > L _B ”.

  With this configuration, when the temperature of the lower region on the inner surface of the bulb portion is likely to be high, the intermediate position (P) of the pair of electrodes serving as the center of the heat source and the lower position on the inner surface of the bulb portion. The distance to the side region is longer than the distance between the intermediate position (P) of the pair of electrodes and the upper region on the inner surface of the tube portion. Since the lower region on the inner surface of the tube portion can be separated from the heat source to some extent, the temperature increase in the lower region on the inner surface of the tube portion is suppressed, and the upper region on the inner surface of the tube portion is suppressed. The temperature difference between the temperature and the temperature of the lower region can be reduced, and as a result, it is possible to further increase the brightness while extending the life.

  Therefore, the arc tube of the present invention is an arc tube capable of further increasing the brightness while extending the life.

  The light source device of the present invention includes a light-emitting tube according to the present invention and a reflector having a reflective concave surface that is disposed on one sealing portion side of the light-emitting tube and reflects light from the light-emitting tube toward an illuminated region side. It is characterized by providing.

  For this reason, according to the light source device of the present invention, since the above-described excellent arc tube is provided, the light source device can achieve higher luminance while extending its life.

  In the light source device of the present invention, the reflection concave surface of the reflector is configured to correct and reflect the refraction when light emitted through the tube wall of the tube portion is refracted by the tube wall. It is preferable to have a curved surface shape.

  With this configuration, it is possible to correctly reflect the light emitted through the tube wall (the upper tube wall and the lower tube wall) of the bulb part toward an optical element to be described later. . For example, when the reflector is an ellipsoidal reflector, light emitted through the tube wall of the bulb part can be reflected toward the second focal position of the ellipsoidal reflector. In addition, when the reflector is a parabolic reflector, it is possible to reflect the light emitted through the tube wall of the bulb part toward the illuminated region as light substantially parallel to the illumination optical axis. .

  In the light source device of the present invention, the light emitting device is disposed on the other sealing portion side of the arc tube so as to cover the outer surface of the bulb portion on the illuminated area side, and the light from the arc tube is directed to the bulb portion. It is preferable to further include a secondary mirror having a reflective concave surface that reflects toward the surface.

By the way, it is possible to improve the light utilization efficiency and to reduce the size of the reflector by disposing the reflecting means in the sealing portion of the arc tube, thereby realizing a high-luminance and compact light source device. However, since almost half of the bulb portion is covered by the reflecting means, the light source device in which the reflecting means is disposed in the sealing portion of the arc tube has such a reflecting means. There is a tendency that the temperature of the bulb portion tends to be higher than that of the light source device that is not used.
In the present invention, as described above, it is possible to suppress the overall temperature of the tube bulb portion from being increased, and thus the reflecting means is disposed in the sealing portion of the arc tube as described above. This is particularly effective for the light source device.

  In addition, the concave concave surface of the secondary mirror has a curved shape that reflects and corrects the refraction when light emitted through the tube wall of the bulb part is refracted by the tube wall. It is preferable.

  With this configuration, it is possible to correctly reflect light that passes through the tube wall of the tube portion and is emitted in the sub-mirror direction toward an intermediate position between the pair of electrodes that are light sources.

  The projector of the present invention projects an illumination device including the light source device of the present invention, an electro-optic modulation device that modulates illumination light from the illumination device according to image information, and light modulated by the electro-optic modulation device. A projection optical system.

  For this reason, according to the projector of the present invention, since the above-described excellent light source device is provided, the projector has a long-life light source device and a high brightness.

  In the projector according to the aspect of the invention, it is preferable that the projector further includes a cooling mechanism for cooling the light source device.

  With this configuration, it is possible to suppress the temperature rise of the light source device, and it is possible to further increase the luminance while extending the life of the light source device.

  The arc tube, light source device, and projector of the present invention will be described below based on the embodiments shown in the drawings.

[Embodiment 1]
1. Configuration of Arc Tube 20, Light Source Device 110, and Projector 1000 FIG. 1 is a top view schematically showing an optical system of the projector 1000 according to the first embodiment. FIG. 2 is a view for explaining the arc tube 20 and the light source device 110 according to the first embodiment. 2A is a side view schematically showing the light source device 110, and FIG. 2B is a cross-sectional view of the peripheral portion of the bulb portion 30 in the arc tube 20 as viewed from the side.

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. Let it be an axial direction (a direction perpendicular to the paper surface in FIG. 1 and perpendicular to the z-axis).
Further, in the following description, a case where projector 1000 is arranged in a so-called stationary state will be exemplified. Therefore, the gravity direction is the lower direction (for example, the y (−) direction in FIG. 2A).

  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; 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; The projector includes a cooling mechanism 700 (not shown).

  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. The array 130, the polarization conversion element 140 that converts each partial light beam from the second lens array 130 into approximately one type of linearly polarized light having the same polarization direction and emits it, and each partial light beam emitted from the polarization conversion element 140 And a superimposing lens 150 for superimposing in the illuminated area.

  As shown in FIGS. 1 and 2A, the light source device 110 includes an ellipsoidal reflector 10 as a reflector, and an arc tube 20 having a light emission center near the first focal point of the ellipsoidal reflector 10. 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.

If the conditions of the constituent elements 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 mercury or a rare gas is contained in the tube portion 30. 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. 2B, the tube portion 30 includes a pair of electrodes 42 and 52 in a cross section of the tube portion 30 when cut along a virtual plane that includes the illumination optical axis 100ax and extends in the direction of gravity. The intermediate position is a point P, the position that is the lowest on the inner surface of the tube portion 30 is the point A, the position that is the uppermost side on the inner surface of the tube portion 30 is the point B, A position that is the lowest side with respect to gravity on the outer surface of the tube portion 30 is a point C, a position that is the uppermost side with respect to the gravity on the outer surface of the tube portion 30 is a point D, and from the point P to the point A distance and L _a, the distance from the point P to the point B and L _B, the distance from the point P to the point C and L _C, the distance from the point P to the point D and L _D, the point from point C D Let the distance to be L. At this time, in the arc tube 20 according to the first embodiment, _{"(L C -L A) = (} L D -L B) " and so as to satisfy the relation of _{"L A} ≠ _{L B"} of the arc tube 20 A tube portion 30 is configured.

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

  The reflection concave surface 14 corrects and reflects the refraction when light emitted through the upper tube wall 36 and the lower tube wall 38 of the tube portion 30 is refracted by the tube walls 36 and 38. It has such a curved shape.

For example, crystallized glass, alumina (Al ₂ O ₃ ), or the like can be suitably used as the material of the base material constituting the ellipsoidal reflector 10. On 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 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 small lenses 122 are provided in a plane orthogonal to the illumination optical axis 100ax. It has a configuration arranged in a matrix of rows and columns. 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 has a function of forming an image of each first small lens 122 of the first lens array 120 in the vicinity of the image forming area of the liquid crystal devices 400R, 400G, and 400B together with the superimposing lens 150. The second lens array 130 has substantially the same configuration as the first lens array 120, and a plurality of second small lenses 132 are arranged in a matrix of a plurality of rows and a plurality of columns in a plane orthogonal to the illumination optical axis 100ax. Have a configuration.

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 linearly polarized light component among the polarized light components included in the illumination light beam from the light source device 110 and reflects the other linearly polarized light component in a direction perpendicular to the illumination optical axis 100ax, and A reflection layer that reflects the other linearly polarized light component reflected by the polarization separating layer in a direction parallel to the illumination optical axis 100ax, and a phase difference that converts one linearly polarized light component transmitted through the polarized light separating layer into the other linearly polarized light component And a board.

  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 is arranged so that the optical axis of the superimposing lens 150 and the illumination optical axis 100ax of the illumination device 100 substantially coincide. The superimposing lens 150 may be composed of a compound lens in which a plurality of lenses are combined.

  The color separation light guide optical system 200 includes dichroic mirrors 210 and 220, reflection mirrors 230, 240 and 250, an incident side lens 260, and a relay lens 270. The color separation light guide optical system 200 separates the illumination light beam emitted from the superimposing lens 150 into three color lights of red light, green light, and blue light, and each of the three color liquid crystal devices 400R to be illuminated. , 400G, 400B.

The liquid crystal devices 400 </ b> R, 400 </ b> G, and 400 </ b> B modulate the illumination light beam according to the image information and are the illumination target of the illumination device 100.
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, an incident light that will be described later is used according to given image information using a polysilicon TFT as a switching element. Modulates the polarization direction of one type of linearly polarized light emitted from the side polarizing plate.

  Condensing lenses 300R, 300G, and 300B are disposed in the front stage of the optical path of the liquid crystal devices 400R, 400G, and 400B.

  Although not shown here, incident-side polarizing plates are interposed between the condenser lenses 300R, 300G, and 300B and the liquid crystal devices 400R, 400G, and 400B, and the liquid crystal devices 400R, 400G, and 400B are disposed. Between the 400B and the cross dichroic prism 500, an exit side polarizing plate is interposed. The incident-side polarizing plate, the liquid crystal devices 400R, 400G, and 400B and the exit-side polarizing plate modulate light of each color light incident thereon.

  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 exit 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.

The projector 1000 is provided with a cooling mechanism 700 (not shown). The cooling mechanism 700 includes at least a cooling fan 710 that cools the light source device 110 and a cooling air flow path 720 that allows cooling air from the cooling fan 710 to pass through (both not shown). The cooling mechanism 700 may be configured to cool not only the light source device 110 but also other optical elements (for example, the liquid crystal devices 400R, 400G, and 400B).

  Note that the above configuration is a configuration in which the temperature of the upper region 32 on the inner surface of the tube portion 30 tends to increase.

2. Method for Manufacturing Arc Tube 20 Next, a method for manufacturing the arc tube 20, here, mainly a method for forming the tube portion 30 will be described with reference to the drawings. In addition, about a manufacturing method other than the tube part 30, a conventionally well-known means shall be used and description is abbreviate | omitted.

FIG. 3 is a view for explaining a method of forming the tube portion 30 in the arc tube 20 according to the first embodiment.
First, a tubular member 70 having an outer diameter corresponding to the outer diameter of the sealing portions 40 and 50 is prepared (not shown). As a material of the tubular member 70, for example, quartz glass can be suitably used.

Next, the central portion 72 of the tubular member 70 is heated (see FIG. 4A).
Thereafter, if necessary, the end portions 74 and 76 of the tubular member 70 are moved toward the central portion 72 of the tubular member 70 to perform meat gathering (see FIG. 4B).

  Further, the tubular member 70 is disposed inside the molds 78 and 80, and an internal pressure is applied by an inert gas, and the central portion 72 of the tubular member 70 is expanded so as to have a predetermined shape corresponding to the tube portion 30. As the inert gas, for example, argon gas or nitrogen gas can be suitably used.

3. For this reason, according to the arc tube 20 according to the first embodiment, the distance between the intermediate position P of the pair of electrodes 42 and 52 serving as the center of the heat source and the upper region 32 on the inner surface of the tube portion 30 is a pair. Since the distance between the intermediate position P of the electrodes 42 and 52 and the lower region 34 on the inner surface of the tube portion 30 is longer, the upper region 32 on the inner surface of the tube portion 30 where the temperature tends to rise due to thermal convection or the like. Can be separated from the heat source to some extent, the temperature rise of the upper region 32 on the inner surface of the tube portion 30 is suppressed, and the temperature of the upper region 32 and the lower region 34 on the inner surface of the tube portion 30 are suppressed. The temperature difference from the temperature can be reduced. As a result, it is possible to further increase the luminance while extending the life.

  In addition, according to the light source device 110 according to the first embodiment, since the above-described excellent arc tube 20 is provided, the light source device can achieve higher luminance while extending its life.

  Further, according to the light source device 110 according to the first embodiment, the reflection concave surface 14 is configured such that light emitted from the center of the tube bulb 30 through the tube walls 36 and 38 of the tube bulb 30 is the tube walls 36 and 38. When the light beam is refracted by the curved surface shape, the light beam has a curved surface shape that reflects and corrects the refraction, so that the light emitted through the tube walls 36 and 38 of the bulb part 30 is reflected at the second focal position of the elliptical reflector 10. It becomes possible to reflect toward

  Since the projector 1000 according to the first embodiment includes the excellent light source device 110 described above, the projector 1000 includes a long-life light source device and is a high-brightness projector.

  In addition, according to the projector 1000 according to the first embodiment, the projector 1000 further includes the cooling mechanism 700 that cools the light source device 110. Therefore, the temperature rise of the light source device 110 can be suppressed, and the life of the light source device 110 can be extended. It is possible to further increase the brightness.

[Embodiment 2]
FIG. 4 is a view for explaining the arc tube 20a and the light source device 110a according to the second embodiment. 4A is a cross-sectional view of the peripheral portion of the bulb portion 30a in the arc tube 20a as viewed from the side, and FIG. 4B is a side view schematically showing the light source device 110. FIG.

  In the arc tube 20a of the second embodiment, the upper region 32a of the tube bulb 30 is cooled more strongly by the cooling mechanism 700a in an attempt to cool the temperature of the upper region 32a on the inner surface of the tube bulb 30a to a predetermined temperature or lower. Therefore, the temperature of the lower region 34a on the inner surface of the tube portion 30a tends to increase.

The arc tube 20a according to the second embodiment basically has the same configuration as the arc tube 20 according to the first embodiment, but the arrangement of the bulb portion 30a is different from that of the arc tube 20 according to the first embodiment. . That is, in the arc tube 20a according to the second embodiment, the relationship “L _A > L _B ” is satisfied.

  Therefore, according to the arc tube 20a according to the second embodiment, the distance between the intermediate position P of the pair of electrodes 42 and 52 serving as the center of the heat source and the lower region 34a on the inner surface of the tube portion 30a is a pair of Since it is longer than the distance between the intermediate position P of the electrodes 42 and 52 and the upper region 32a on the inner surface of the tube portion, the lower region 34a on the inner surface of the tube portion 30a can be separated from the heat source to some extent, The temperature increase of the lower region 34a on the inner surface of the tube portion 30a can be suppressed, and the temperature difference between the temperature of the upper region 32a and the temperature of the lower region 34a on the inner surface of the tube portion 30a can be reduced. As a result, it is possible to further increase the luminance while extending the life.

  As described above, the arc tube 20a according to the second embodiment is similar to the effect obtained from the arc tube 20 according to the first embodiment, although the arrangement of the bulb portion 30a is different from that of the arc tube 20 according to the first embodiment. Thus, the arc tube can be further increased in brightness while extending its life.

  The arc tube 20a according to the second embodiment has the same configuration as that of the arc tube 20 according to the first embodiment except for the arrangement of the bulb portion 30a. It has a corresponding effect among the effects it has.

[Embodiment 3]
FIG. 5 is a side view schematically showing the light source device 110b according to the third embodiment.

  The light source device 110b according to the third embodiment basically has the same configuration as the light source device 110 according to the first embodiment, but is different from the light source device 110 according to the first embodiment in that it further includes a secondary mirror 60.

  The secondary mirror 60 is a reflecting means that covers approximately half of the bulb portion 30 and is disposed to face the reflective concave surface 14b of the elliptical reflector 10b. The secondary mirror 60 is a sealing portion (the other sealing portion) 50 of the arc tube 20. And a reflective concave surface 64 that reflects the light emitted from the arc tube 20 toward the illuminated area toward the arc tube 20. The light reflected by the secondary mirror 60 passes through the arc tube 20 and enters the ellipsoidal reflector 10b. The secondary mirror 60 is fixed to the sealing portion 50 of the arc tube 20 with an inorganic adhesive such as cement filled in the opening 62 of the secondary mirror 60. The curved shape of the reflective concave surface 64 is a spherical shape centered on the intermediate position P between the pair of electrodes 42 and 52.

As a material constituting the secondary mirror 60, for example, translucent alumina is used. Thereby, heat dissipation can be improved. In addition to alumina, materials such as quartz glass, sapphire, and ruby may be used.
On 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.

For this reason, according to the light source device 110b according to the third embodiment, the light emitted from the tube portion 30 toward the illuminated region is reflected by the secondary mirror 60 toward the ellipsoidal reflector 10b. Therefore, it is possible to effectively use the light that has been emitted to the illuminated area side and has not been effectively used. For this reason, it is possible to increase the luminance of the light source device 110b.
Further, it is not necessary to set the size of the ellipsoidal reflector 10b so as to cover the end of the arc tube 20 to be illuminated, and the ellipsoidal reflector 10b can be reduced in size, and as a result. A compact light source device 110b can be realized. Furthermore, since the ellipsoidal reflector 10b can be reduced in size, the size of the optical element arranged in the latter stage of the optical path can be reduced, so that a compact projector can be obtained.

By the way, by arranging the secondary mirror 60 in the sealing portion 50 of the arc tube 20 as described above, it is possible to realize a light source device 110b with high brightness and compactness. Is covered by the secondary mirror 60, the light source device 110b in which the secondary mirror 60 is disposed in the sealing portion 50 of the arc tube 20 is more than the light source device in which such a secondary mirror is not disposed. There exists a tendency for the temperature of the tube part 30 to become high easily.
However, since the arc tube 20 according to Embodiment 3 can suppress the overall temperature of the bulb portion 30 from being increased as described above, the arc tube 20 is sealed in this way. The effect is particularly great for the light source device 110b in which the secondary mirror 60 is disposed in the stop portion 50.

As described above, the light source device 110b according to the third embodiment is different from the light source device 110 according to the first embodiment in that the auxiliary mirror 60 is provided, but “L _A < In order to satisfy the relationship of “L _B ”, the arc tube can be further increased in brightness while extending its life.

  The arc tube, the light source device, and the projector according to the present invention have been described based on the above-described embodiments. However, the present invention is not limited to the above-described embodiments, and various aspects can be used without departing from the scope of the present invention. For example, the following modifications are possible.

(1) In the light source device 110b according to the third embodiment, the curved shape of the reflecting concave surface 64 of the secondary mirror 60 is a spherical shape centered on the intermediate position P between the pair of electrodes 42 and 52. Is not limited to this. For example, the curved shape of the reflecting concave surface of the secondary mirror is such that when the light emitted from the center of the tube part through the upper tube wall and the lower tube wall of the tube part is refracted by the tube wall, It is also preferable to have a curved surface shape that reflects and corrects refraction.

(2) In the light source device according to each of the above embodiments, an elliptical reflector is used as the reflector. However, the present invention is not limited to this, and it is also preferable to use a parabolic reflector. In this case, the concave lens may not be provided.

(3) In the projectors according to the above embodiments, the lens integrator optical system including a lens array is used as the light uniformizing optical system. However, the present invention is not limited to this, and the rod including a rod member is used. An integrator optical system can also be preferably used.

(4) Although the projector according to each of the above embodiments is a transmissive projector, 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.

(5) In the projector according to each of the above embodiments, 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, The present invention is also applicable to a projector using one or four or more liquid crystal devices.

(6) In the projector 1000 according to each of the above embodiments, the liquid crystal device is used as the electro-optic modulation device, but 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.

(7) The present invention is applied to a rear projection projector that projects from a side opposite to the side that observes the projected image, even when applied to a front projection projector that projects from the side that observes the projected image. Is also possible.

FIG. 3 is a top view schematically showing an optical system of the projector according to the first embodiment. The figure shown in order to demonstrate the arc tube 20 and the light source device 110 which concern on Embodiment 1. FIG. The figure shown in order to demonstrate the shaping | molding method of the bulb part 30 in the arc tube 20 which concerns on Embodiment 1. FIG. The figure shown in order to demonstrate the arc tube 20a and light source device 110a which concern on Embodiment 2. FIG. FIG. 6 is a side view schematically showing a light source device 110b according to a third embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,10b ... Ellipsoidal reflector, 12 ... Opening part, 14, 14b ... Inner surface, 20, 20a ... Arc tube, 30, 30a ... Tube part, 32, 32a ... Upper area | region in the inner surface of a tube part, 33, 33a: Upper region on the outer surface of the tube portion, 34, 34a: Lower region on the inner surface of the tube portion, 35, 35a: Lower region on the outer surface of the tube portion, 36, 36a: In the tube portion Upper tube wall, 38, 38a ... Lower tube wall in the bulb portion, 40, 50 ... Sealing portion, 42, 52 ... Electrode, 44, 54 ... Metal foil, 46, 56 ... Lead wire, 60 ... Deputy Mirror, 62 ... opening, 64 ... inner surface, 70 ... tubular member, 72 ... central portion of tubular member, 74, 76 ... end of tubular member, 78, 80 ... mold, 90 ... concave lens, 100 ... lighting device, 100ax ... illumination optical axis, 110, 110a, 110b ... light Apparatus 120 ... first lens array 122 ... first small lens 130 ... second lens array 132 ... second small lens 140 ... polarization conversion element 150 ... superimposed lens 200 ... color separation light guide optical system, 210, 220 ... Dichroic mirror, 230, 240, 250 ... Reflection 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, 700a ... cooling mechanism, 710a ... cooling fan, 720a ... cooling air flow path, 1000, 1000a ... projector, A ... position on the inner side of the tube portion that is the lowest side with respect to gravity, B ... the uppermost position with respect to gravity on the inner surface of the tube part, C ... on the outer surface of the tube part Position that is the lowest side with respect to force, D: Position that is the uppermost side with respect to gravity on the outer surface of the tube portion, F: Cooling air, I: Inert gas, L: Distance from point C to point D L _A ... distance from point P to point A, L _B ... distance from point P to point B, L _C ... distance from point P to point C, L _D ... distance from point P to point D, P ... Intermediate position of a pair of electrodes, SCR ... Screen

Claims (8)

A tube section containing a pair of electrodes;
An arc tube having a pair of sealing portions extending on both sides of the bulb portion,
The point P is an intermediate position of the pair of electrodes in a cross section when the arc tube is cut in a virtual plane along the direction of gravity including the axis of the pair of sealing portions,
A position that is the lowest side with respect to gravity on the inner surface of the tube portion is a point A,
A position which is the uppermost side with respect to gravity on the inner surface of the tube portion is a point B,
A position that is the lowest side with respect to gravity on the outer surface of the tube portion is a point C,
A position that is the uppermost position with respect to gravity on the outer surface of the tube portion is a point D,
The distance from the point P to the point A and L _A,
Let L _B be the distance from point P to point B.
Let L _C be the distance from point P to point C.
When the distance from the point P to the point D is L _D ,
An arc tube characterized by satisfying a relationship of “(L _C −L _A ) = (L _D −L _B )” and “L _A ≠ L _B ”. The arc tube of claim 1, wherein
Arc tube and satisfying the relation of "L _{A <L B".} The arc tube of claim 1, wherein
An arc tube characterized by satisfying a relationship of “L _A > L _B ”. The arc tube according to any one of claims 1 to 3,
A light source device comprising: a reflector disposed on one sealing portion side of the arc tube and having a reflective concave surface that reflects light from the arc tube toward an illuminated region side. The light source device according to claim 4,
The reflective concave surface of the reflector has a curved shape that reflects and corrects the refraction when light emitted through the tube wall of the bulb portion is refracted by the tube wall. A light source device. The light source device according to claim 4 or 5,
It has a reflective concave surface that is disposed on the other sealing portion side of the arc tube so as to cover an outer surface of the bulb portion on the illuminated area side and reflects light from the arc tube toward the bulb portion. A light source device further comprising a secondary mirror. A lighting device comprising the light source device according to any one of claims 4 to 6,
An electro-optic modulation device that modulates illumination light from the illumination device according to image information;
A projector comprising: a projection optical system that projects light modulated by the electro-optic modulation device. The projector according to claim 7, wherein
A projector further comprising a cooling mechanism for cooling the light source device.

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