JP2011165490A - Light source unit and projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source unit that can appropriately adjust a temperature of an arc tube, is simplified in structure, and suppresses noise generation. <P>SOLUTION: The light source unit 252 has: an arc tube 11 including a light emitting portion 15 emitting light, a second sealing portion 16 and a first sealing portion 17; a secondary reflecting mirror 13 including a secondary reflecting surface 13a covering a part of the periphery of the light emitting portion 15 and an extending portion 23 covering the first sealing portion 17; a primary reflecting mirror 12 for reflecting light reflected at the secondary reflecting surface 13a; and a first electrode 18 and a second electrode 19 that are provided with the secondary reflecting mirror 13 interposed therebetween. The first electrode 18 is arranged to be shifted toward the light emitting portion 15 side as compared with the second electrode 19, and induces an ionic wind by an application of a voltage, allowing air between the secondary reflecting surface 13a and the light emitting portion 15 to flow. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a light source device and a projector, and more particularly to a technology of a light source device having a reflector.

  In a lamp used as a light source of a projector, for example, a discharge lamp such as an extra-high pressure mercury lamp, a reflector (reflecting mirror) that reflects light emitted from an arc tube is used. In order to obtain a bright image efficiently with a projector, a configuration of a light source device for improving the utilization efficiency of light emitted from an arc tube has been proposed. For example, a technique of providing a sub-reflecting mirror that covers a part of the arc tube separately from a reflector as a main reflecting mirror has been proposed (for example, see Patent Document 1). The light reflected by the sub-reflecting mirror passes through the arc tube, enters the main reflecting mirror, and is reflected toward the front side. This makes it possible to reduce the thickness of the light source device while efficiently making the light emitted from the arc tube proceed to the optical system that uses the light from the light source device.

Japanese Patent No. 3350003

  Lamps used in projectors need to be cooled by cooling air or the like because much of the supplied electric energy becomes heat and becomes high temperature. In the case of a configuration including a sub-reflecting mirror, it is difficult to cool a portion covered by the sub-reflecting mirror on the surface of the light emitting unit. In this case, since the heat radiation property is different between the portion covered by the sub-reflecting mirror and the other portion of the surface of the light emitting portion, there arises a problem that it is difficult to appropriately adjust the temperature of the arc tube. A portion of the arc tube that is not sufficiently cooled may cause the transparent member constituting the arc tube to be crystallized by heat and become cloudy. In order to cool the arc tube, it may be possible to provide a blower fan or a duct. However, problems such as a complicated structure and generation of noise by the blower fan occur.

  The present invention has been made in view of the above-described problems, and provides a light source device capable of appropriately adjusting the temperature of the arc tube, simplifying the structure and suppressing noise generation, and a projector having the light source device. The purpose is to do.

  In order to solve the above-described problems and achieve the object, the present invention provides an arc tube comprising: a light emitting unit that emits light; and a first sealing unit that is integrally provided on one side of the light emitting unit; A sub-reflecting mirror comprising: a sub-reflecting part that covers a part of the periphery of the light-emitting part and has a sub-reflecting surface that reflects light emitted from the light-emitting part; and a first extending part that covers the first sealing part. A main reflecting mirror that reflects the light emitted from the light emitting unit and the light reflected by the sub-reflecting surface, a first electrode disposed on the opposite surface side of the arc tube with respect to the sub-reflecting mirror, and a first A second electrode disposed between the sealing portion and the first extending portion, the first electrode being disposed at a position closer to the light emitting portion than the second electrode, and the first electrode and the second electrode By applying a voltage between the two, an ion wind is generated, and air between the sub-reflecting surface and the light emitting portion can flow.

  Since the air between the sub-reflecting surface and the light-emitting portion can be flowed by the ion wind, the light-emitting portion that is the portion covered by the sub-reflecting mirror in the arc tube can be effectively cooled. Thereby, appropriate temperature control of the arc tube becomes possible. Moreover, since a voltage should just be applied between a 1st electrode and a 2nd electrode, a light emission part can be cooled, without using a ventilation fan or a duct. Thereby, simplification of a structure and generation | occurrence | production of noise can be suppressed. The ion wind is generated by creeping discharge generated when a predetermined voltage is applied between the first electrode and the second electrode arranged with a sub-reflector made of an insulator such as quartz sandwiched therebetween. It is wind to do. When a predetermined voltage is applied between the first electrode and the second electrode, air molecules are ionized around the first electrode and move toward the second electrode. The wind generated by the movement of the ionized air is called ion wind.

  Further, creeping discharge is likely to occur even with an electrode having a sharp tip as compared with corona discharge, and air may be ionized in a wide range. For example, even with a flat electrode at the tip, air may be ionized around substantially the entire area of the flat portion, and a stronger ion wind can be generated. Therefore, the air between the light emitting part and the sub-reflecting surface can be largely flowed to cool the light emitting part more effectively.

  Further, creeping discharge can be generated even when an AC voltage is applied, so that even when an AC voltage is supplied from a power source, an ion wind can be generated without using a voltage converting component. . Therefore, it is possible to reduce costs by reducing the number of components that convert voltage. In addition, since there is an insulator between the first electrode and the second electrode, it is difficult for sparks to occur between the two electrodes. Thereby, the destruction of the electrode due to sparks and the influence on other electronic devices can be suppressed.

  Moreover, as a preferable aspect of the present invention, it is desirable that the first electrode is covered with an insulating layer. Since the first electrode is covered with the insulating film, the user can be prevented from touching the first electrode by mistake. That is, it is possible to prevent an electric shock accident due to contact with the first electrode to which a voltage is applied. Moreover, generation | occurrence | production of the ion wind on the outer side of a sub-reflection mirror can be suppressed.

  Moreover, as a preferable aspect of the present invention, an opening penetrating the surface on the arc tube side and the opposite surface is formed in the first extending portion at a position farther from the light emitting portion than the second electrode. It is desirable. Since the opening is formed in the extending portion, air is easily supplied from the outside of the sub-reflecting mirror, so that the air volume of the ion wind can be increased.

  As a preferred embodiment of the present invention, it is desirable that the first electrode extends from the first extending portion to the back surface of the sub-reflecting surface. Since the first electrode extends from the first extending portion to the back surface of the sub-reflection surface, the ion wind can be more reliably guided between the light emitting portion and the sub-reflection surface.

  Moreover, as a preferable aspect of the present invention, the main reflecting mirror has substantially the same shape as a curved surface obtained by cutting a rotating curved surface obtained by rotating a predetermined curve about the central axis at a predetermined surface. None, the sub-reflecting mirror desirably covers the side opposite to the side where the main reflecting mirror is provided with respect to the light emitting portion. With this configuration, the light source device can be thinned.

  Moreover, as a preferable aspect of the present invention, the arc tube includes a second sealing portion integrally provided on the other side of the light emitting portion, and the sub-reflecting mirror includes a second extending portion that covers the second sealing portion. A third electrode disposed between the sub-reflecting mirror and the arc tube, and a fourth electrode disposed on the opposite side of the arc tube side with respect to the second extending portion, the third electrode Is arranged so as to be shifted to the light emitting part side with respect to the fourth electrode, and an ion wind is generated by applying a voltage between the third electrode and the fourth electrode, and the air between the sub-reflecting surface and the light emitting part is It is desirable to be able to flow. Since the ion wind can be generated between the second extending portion and the second sealing portion, the air between the sub-reflecting surface and the light emitting portion can be made to flow more greatly, and light can be emitted more effectively. The tube can be cooled.

  In a preferred embodiment of the present invention, the main reflecting mirror has substantially the same shape as a rotating curved surface obtained by rotating a predetermined curve around the central axis, and the sub-reflecting mirror covers the light emitting section. It is desirable to cover the irradiation surface side. Thereby, it is possible to obtain a light source device that efficiently advances the light emitted from the light emitting unit toward the front side.

  The projector according to the aspect of the invention includes the light source device, a voltage application unit that applies an AC voltage between the first electrode and the second electrode, and spatial light that modulates light emitted from the light source device according to an image signal. And a modulation device. By using the light source device, it is possible to obtain a projector that can effectively cool the light emitting unit while suppressing the complexity of the structure and the generation of noise. In addition, since it is difficult for a spark to occur between the first electrode and the second electrode, it is possible to suppress the destruction of the electrode due to the spark and the influence on other electronic devices, and the projector can be stably operated. be able to.

It is an external appearance perspective view which shows schematic structure of the light source device which concerns on Example 1 of this invention. It is a disassembled perspective view of a light source device. It is a perspective view of the subreflector which attached the 1st electrode and the 2nd electrode. It is a cross-sectional view of a light source device. 6 is a cross-sectional view of a light source device according to Modification 1 of Embodiment 1. FIG. 6 is a cross-sectional view of a light source device according to a second modification of the first embodiment. FIG. 6 is a cross-sectional view of a light source device according to Example 2. FIG. 6 is a cross-sectional view of a light source device according to Example 3. FIG. It is the figure which looked at the arc tube portion of the light source device from the front side. It is a figure which shows schematic structure of the projector which concerns on Example 4 of this invention.

  Embodiments of the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is an external perspective view showing a schematic configuration of a light source device 252 according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of the light source device 252 shown in FIG. FIG. 3 is a perspective view of the sub-reflecting mirror to which the first cooling electrode (first electrode) 18 and the second cooling electrode (second electrode) 19 are attached. 4 is a cross-sectional view of the light source device 252 shown in FIG. The light source device 252 includes an arc tube 11, a main reflecting mirror 12, a sub-reflecting mirror 13, a first cooling electrode (first electrode) 18, and a second cooling electrode (second electrode) 19. The light source device 252 emits light including red (R) light, green (G) light, and blue (B) light. In the description of the embodiments of the present application, the X axis is an axis orthogonal to the central axis AX of the arc tube 11. The Y axis is an axis orthogonal to the central axis AX and the X axis. The Z axis is an axis parallel to the central axis AX. The direction of the arrow on the Z axis represents the direction from the light source device 252 toward the irradiated surface (not shown). The arrow direction of each axis is a positive direction, and the opposite direction is a negative direction. A positive direction side (side with the irradiated surface) along the Z axis with respect to the light source device 252 is referred to as a front side, and a negative direction side is referred to as a rear side. Further, a positive direction side along the Y axis with respect to the light source device 252 is referred to as an upper side, and a negative direction side is referred to as a lower side.

  The arc tube 11 is, for example, an ultra high pressure mercury lamp. The arc tube 11 includes a light emitting portion 15 having a substantially spherical shape. Light is emitted from the light emitting unit 15 by forming an arc between the arc electrodes 3 and 4 inside the light emitting unit 15. The light emitting unit 15 is integrally provided with a second sealing unit 16 and a first sealing unit 17. The first sealing part 17 has a cylindrical shape and is provided on one side (rear side) of the light emitting part 15. The second sealing portion 16 has a cylindrical shape and is provided on the other side (front side) of the light emitting portion 15. With the above configuration, the arc tube 11 has a shape in which the light emitting part 15 is sandwiched between the second sealing part 16 and the first sealing part 17.

  The main reflecting mirror 12 includes a main reflecting surface 12 a that reflects light emitted from the light emitting unit 15. The main reflecting mirror 12 reflects the light emitted from the light emitting unit 15 by the main reflecting surface 12a and advances it to the front side. The main reflecting surface 12a has substantially the same shape as a curved surface obtained by cutting a spheroidal surface obtained by rotating an ellipse about the central axis AX along a predetermined plane. In the first embodiment, the predetermined plane is a plane including the central axis AX of the arc tube 11. The predetermined plane may be a plane other than the plane including the central axis AX in order to increase the light use efficiency. The predetermined plane may be, for example, a plane parallel to the center axis AX or a plane having an angle with respect to the center axis AX.

  The main reflecting mirror 12 is configured by vapor-depositing a highly reflective member such as a dielectric multilayer film or a metal member on the surface of a base material formed into a desired shape. As the highly reflective member, a member having a high reflectance with respect to light having a wavelength in the visible region is used. By using the main reflecting mirror 12 including the main reflecting surface 12a having a shape obtained by cutting the spheroid, the light source device 252 can be made thinner than a light source device using a reflecting mirror whose spheroid surface is not cut. it can. The main reflecting surface 12a is not limited to the substantially same shape as the curved surface obtained by cutting the spheroid. For example, the shape may be substantially the same as a curved surface obtained by cutting a rotating curved surface obtained by rotating a predetermined curve such as a parabola, or a free curved surface shape.

  The sub-reflecting mirror 13 includes a sub-reflecting portion 20 on which a sub-reflecting surface 13 a that reflects light emitted from the light emitting portion 15 is formed, and an extending portion (first extending portion) 23. The sub-reflecting mirror 13 reflects the light emitted from the light emitting unit 15 toward the light emitting unit 15 at the sub reflecting surface 13a. The light reflected by the sub-reflecting surface 13a enters the main reflecting surface 12a, is reflected by the main reflecting surface 12a, and travels forward. The sub-reflection surface 13a covers a part of the periphery of the light emitting unit 15 from below. A gap is provided between the sub-reflecting unit 20 and the light emitting unit 15. The sub-reflecting mirror 13 is configured by evaporating a highly reflective member such as a dielectric multilayer film on the surface of a base material formed into a desired shape. In Example 1, the base material used for the sub-reflecting mirror 13 is an insulator such as quartz. The dielectric multilayer film is also an insulator. As the highly reflective member, a member having a high reflectance with respect to light having a wavelength in the visible region is used. By providing the main reflecting mirror 12 and the sub reflecting mirror 13, the light emitted from the light emitting unit 15 can be efficiently advanced to the front side.

  The extending portion 23 is formed on the rear portion of the sub-reflecting portion 20 so as to cover a part of the first sealing portion 17. The extension part 23 is adhered to the fixing part 27, whereby the sub-reflecting mirror 13 in the light source device 252 is positioned and fixed. The fixing portion 27 is for fixing the arc tube 11, the main reflecting mirror 12, and the sub-reflecting mirror 13 together. The extending portion 23 is formed with an opening 23a that penetrates the surface on the arc tube 11 side and the opposite surface. Hereinafter, the side on which the arc tube 11 is arranged with respect to the sub-reflecting mirror 13 is referred to as the inner side, and the opposite side is also referred to as the outer side.

  The first cooling electrode 18 and the second cooling electrode 19 are arranged so that the sub-reflecting mirror 13 is sandwiched between the electrodes 18 and 19. The first cooling electrode 18 and the second cooling electrode 19 are for causing an ion wind by creeping discharge by applying a voltage between the electrodes 18 and 19.

  The first cooling electrode 18 is formed by bending a plate-like metal member in accordance with the shape of the extending portion 23, and includes a discharge portion 18c at the tip. The first cooling electrode 18 is disposed outside the extending portion 23. The first cooling electrode 18 is covered with an insulating film (insulating layer) 21.

  The second cooling electrode 19 is formed by bending a plate-shaped metal member in accordance with the shape of the extending portion 23. The second cooling electrode 19 includes a discharge part 19c at the tip. The second cooling electrode 19 is affixed inside the extending portion 23. As a result, the second cooling electrode 19 is disposed between the first sealing portion 17 and the extending portion 23. The second cooling electrode 19 is arranged such that the discharge part 19c is positioned closer to the light emitting part 15 than the opening 23a.

  Further, the second cooling electrode 19 is disposed such that the discharge portion 19 c is shifted to the rear side of the discharge portion 18 c of the first cooling electrode 18. With this arrangement, the discharge part 18c of the first cooling electrode 18 is arranged at a position shifted from the discharge part 19c of the second cooling electrode 19 to the light emitting part 15 side. The cooling electrodes 18 and 19 may be formed of a metal film or an ITO film (transparent conductive film). In particular, in the case of an ITO film, the difference between the linear expansion coefficient and the linear expansion coefficient of the sub-reflecting mirror 13 is often smaller than the difference between the linear expansion coefficient of the metal member and the linear expansion coefficient of the sub-reflecting mirror 13. When pasted on the mirror 13, peeling due to temperature change can be made difficult to occur.

  The first cooling electrode 18 and the second cooling electrode 19 are connected to a voltage application unit (not shown), and a voltage is applied between both the electrodes 18 and 19 to thereby extend the extended portion 23 of the sub-reflecting mirror 13 that is an insulator. Creeping discharge can be caused between the electrodes 18 and 19 arranged with the electrode interposed therebetween. Air molecules ionized in the vicinity of the discharge portion 19c of the second cooling electrode 19 by the creeping discharge are attracted to the discharge portion 18c side of the first cooling electrode 18, and the extension portion 23 and the first sealing portion 17 Move between. The ionized air molecules collide with other air molecules when moving, thereby generating a so-called ion wind from the second cooling electrode 19 toward the first cooling electrode 18. The voltage applied between the electrodes 18 and 19 is preferably an alternating voltage.

  Ion wind is generated between the extending portion 23 and the first sealing portion 17, thereby causing an air flow along the arrow P to flow the air between the light emitting portion 15 and the sub-reflecting surface 13 a. be able to. As a result, it is possible to effectively cool the portion of the arc tube 11 covered by the sub-reflecting mirror 13 and to adjust the temperature of the arc tube 11 appropriately. Further, creeping discharge is likely to occur even with an electrode having a sharp tip as compared with corona discharge, and air may be ionized in a wide range. For example, on one side of the discharge part 19c on the first cooling electrode 18 side, air may be ionized around the substantially entire region of the one side, and a stronger ion wind can be generated. Therefore, the air between the light emitting unit 15 and the sub-reflecting surface 13a can be largely flowed to cool the light emitting unit 15 more effectively.

  In addition, since the opening 23a is formed in the extending portion 23 on the upstream side of the discharge portion 19c in the flow of the ion wind, air is easily supplied from the outside to the inside of the sub-reflecting mirror 13, so that the air volume of the ion wind is reduced. Can be increased.

  Further, since air between the light emitting unit 15 and the sub-reflecting surface 13a can be flowed without providing a blower fan or a duct, it is possible to make the structure complicated and noise problems less likely to occur. Further, since the ion wind can be generated near the portion where the air is desired to flow, that is, between the light emitting portion 15 and the sub-reflecting surface 13a, effective cooling can be performed with a small amount of air.

  In addition, since the sub-reflecting mirror 13 as an insulator is provided between the first cooling electrode 18 and the second cooling electrode 19, it is difficult for sparks to occur between the electrodes 18 and 19. Thereby, the destruction of the electrode due to sparks and the influence on other electronic devices can be suppressed. Further, since the first cooling electrode 18 is covered with the insulating film 21, it is possible to prevent the user from touching the first cooling electrode 18 by mistake. That is, an electric shock accident due to contact with the first cooling electrode 18 in a state where a voltage is applied can be prevented. In addition, since the first cooling electrode 18 is covered with the insulating film 21, it is possible to suppress the generation of ion wind on the outside of the sub-reflecting mirror 13.

  FIG. 5 is a cross-sectional view of the light source device according to the first modification of the first embodiment. In the first modification, the discharge portion 18c of the first cooling electrode 18 extends from the extending portion 23 to the back surface of the sub reflective surface 13a. Since the discharge portion 18c of the first cooling electrode 18 extends from the extending portion 23 to the back surface of the sub-reflecting surface 13a, the ion wind can be more reliably guided between the light emitting portion 15 and the sub-reflecting surface 13a. . Therefore, the air between the light emitting unit 15 and the sub-reflecting surface 13a can flow more reliably and the light emitting unit 15 can be effectively cooled.

  FIG. 6 is a cross-sectional view of the light source device according to the second modification of the first embodiment. In the second modification, the discharge portion 18c of the first cooling electrode 18 is disposed on the back surface of the sub-reflection surface 13a. In accordance with this, the discharge part 19c of the second cooling electrode 19 is also arranged shifted to the light emitting part 15 side as compared with the case shown in FIG. Since the discharge part 18c of the first cooling electrode 18 is disposed on the back surface of the sub-reflection surface 13a, the ion wind can be more reliably guided between the light emitting unit 15 and the sub-reflection surface 13a. Therefore, the air between the light emitting unit 15 and the sub-reflecting surface 13a can flow more reliably and the light emitting unit 15 can be effectively cooled.

  FIG. 7 is a cross-sectional view of the light source device according to Embodiment 2 of the present invention. In addition, the same code | symbol is attached | subjected to the same part as said Example 1, and the overlapping description is abbreviate | omitted. In the second embodiment, an extending portion (second extending portion) 253 that covers the second sealing portion 16 of the arc tube 11 is formed on the side opposite to the side where the extending portion 23 is formed with respect to the sub-reflecting portion 20. Has been. A third cooling electrode (third electrode) 255 and a fourth cooling electrode (fourth electrode) 256 are provided on the extending portion 253 side.

  The third cooling electrode 255 is formed by bending a plate-like metal member in accordance with the shape of the extending portion 253. The third cooling electrode 255 includes a discharge part 255c at the tip. The third cooling electrode 255 is affixed inside the extending portion 253. Accordingly, the third cooling electrode 255 is disposed between the extending portion 253 and the second sealing portion 16.

  The fourth cooling electrode 256 is formed by bending a plate-like metal member in accordance with the shape of the extending portion 253, and includes a discharge portion 256c at the tip. The fourth cooling electrode 256 is disposed outside the extending portion 253. The third cooling electrode 255 is disposed such that the discharge portion 255c is shifted to the rear side of the discharge portion 256c of the fourth cooling electrode 256. With this arrangement, the discharge part 255c of the third cooling electrode 255 is arranged at a position shifted from the discharge part 256c of the fourth cooling electrode 256 to the light emitting part 15 side.

  The third cooling electrode 255 and the fourth cooling electrode 256 are connected to a voltage application unit (not shown), and a voltage is applied between both the electrodes 255 and 256, whereby the extending portion 253 of the sub-reflecting mirror 13 that is an insulator. Creeping discharge can be caused between the electrodes 255 and 256 arranged with the electrode interposed therebetween. Air molecules ionized in the vicinity of the discharge part 255c of the third cooling electrode 255 by the creeping discharge are attracted to the fourth cooling electrode 256 side and move between the extending part 253 and the second sealing part 16. . The ionized air molecules collide with other air molecules when moving, thereby generating a so-called ion wind from the third cooling electrode 255 toward the fourth cooling electrode 256. The voltage applied between the electrodes 255 and 256 is preferably an alternating voltage.

  By generating an ionic wind between the extending portion 253 and the second sealing portion 16, an air flow along the arrow Q can be caused. Therefore, the air between the light emitting portion 15 and the sub-reflecting surface 13a can be made to flow more greatly than when the ion wind is generated only on the first sealing portion 17 side. As a result, the portion of the arc tube 11 covered by the sub-reflecting mirror 13 can be cooled more effectively, and the temperature of the arc tube 11 can be adjusted appropriately. As in the modification of the first embodiment, the third cooling electrode 255 may be extended to the back surface of the sub reflective surface 13a, or may be provided only on the back surface of the sub reflective surface 13a.

  FIG. 8 is a cross-sectional view of the light source device 302 according to the third embodiment of the present invention. In addition, the same code | symbol is attached | subjected to the part same as said Example, and the overlapping description is abbreviate | omitted. The light source device 302 according to the third embodiment has a sub-reflecting mirror 313 on the front side (illuminated surface side) with respect to the light emitting unit 15.

  The main reflecting mirror 312 has substantially the same shape as a spheroidal surface obtained by rotating an ellipse around the central axis AX. The main reflecting mirror 312 is configured by vapor-depositing a highly reflective member such as a dielectric multilayer film or a metal member on the surface of a base material formed into a desired shape. The main reflecting mirror 312 is not limited to the same shape as the ellipsoidal surface, and may be, for example, substantially the same shape as a rotating curved surface obtained by connecting a predetermined curve such as a parabola, or a free curved surface shape.

  The sub-reflecting mirror 313 includes a sub-reflecting portion 320 on which a sub-reflecting surface 313a is formed and an extending portion 323. The sub-reflecting mirror 313 covers a portion of the periphery of the light emitting unit 15 on the front side of the light emitting unit 15 with the sub reflecting unit 320. The sub-reflecting mirror 313 reflects the light emitted from the light emitting unit 15 toward the light emitting unit 15 by the sub reflecting surface 313a. A gap is provided between the sub-reflection surface 313 a and the light emitting unit 15. The sub-reflecting mirror 313 is configured by depositing a dielectric multilayer film as a highly reflective member on the surface of a base material formed into a desired shape. In addition, the base material used for the sub-reflection mirror 313 in the present Example 3 is an insulator. The dielectric multilayer film is also an insulator. By providing the main reflecting mirror 312 and the sub-reflecting mirror 313, the light emitted from the light emitting unit 15 can be efficiently advanced toward the front side.

  In addition, an extending portion 323 that covers the first sealing portion 17 of the arc tube 11 is formed on the front side of the sub-reflecting mirror 313. The extending portion 323 has a cylindrical shape that covers the periphery of the first sealing portion 17. In the third embodiment, the first sealing portion 17 of the arc tube 11 is a first sealing portion 17 provided on the front side of the light emitting portion 15.

  The first cooling electrode 18 is disposed outside the extending portion 323. The second cooling electrode 19 is affixed inside the extending portion 323. The second cooling electrode 19 is disposed so that the discharge portion 19c is shifted to the rear side of the discharge portion 18c of the first cooling electrode 18. With this arrangement, the discharge part 18c of the first cooling electrode 18 is arranged at a position shifted from the discharge part 19c of the second cooling electrode 19 to the light emitting part 15 side.

  FIG. 9 is a view of the arc tube 11 portion of the light source device 302 shown in FIG. 8 as viewed from the front side. The arc tube 11 is positioned and fixed by fixing the first sealing portion 17 and the extending portion 323 with the fixing portion 327. As shown in FIG. 9, the gap between the first sealing portion 17 and the extending portion 323 is not completely filled with the fixing portion 327, and a part of the gap is an opening 330.

  In the above configuration, the first cooling electrode 18 and the second cooling electrode 19 are connected to a voltage application unit (not shown), and a voltage is applied between both the electrodes 18 and 19, whereby the sub-reflecting mirror 313 that is an insulator. Creeping discharge can be caused between the electrodes 18 and 19 arranged with the extending portion 323 therebetween. Air molecules ionized in the vicinity of the discharge portion 19 c of the second cooling electrode 19 by the creeping discharge are attracted to the first cooling electrode 18 side and move between the extending portion 323 and the first sealing portion 17. . The ionized air molecules collide with other air molecules when moving, thereby generating a so-called ion wind from the second cooling electrode 19 toward the first cooling electrode 18. The voltage applied between the electrodes 18 and 19 is preferably an alternating voltage.

  Ion wind is generated between the extending portion 323 and the first sealing portion 17, thereby causing an air flow along the arrow R to flow the air between the light emitting portion 15 and the sub reflective surface 313 a. be able to. Thereby, effective cooling of the portion covered by the sub-reflecting mirror 313 in the arc tube 11 becomes possible, and appropriate temperature adjustment of the arc tube 11 becomes possible.

  In addition, on the upstream side of the discharge part 19c in the flow of the ion wind, the space between the first sealing part 17 and the extending part 323 is not completely filled with the fixing part 327, and the opening 330 is formed. Since air is easily supplied from the outside of the sub-reflecting mirror 313, the air volume of the ion wind can be increased.

  FIG. 10 is a diagram illustrating a schematic configuration of the projector 1 according to the fourth embodiment of the invention. The projector 1 is a front projection type projector that projects light onto a screen (not shown) and observes an image by observing light reflected on the screen. The projector 1 includes the light source device 252 according to the first embodiment (see also FIGS. 1, 2, 3, and 4). The light source device 252 emits light including red (R) light, green (G) light, and blue (B) light. A voltage application unit 30 is connected to the light source device 252. The voltage application unit 30 applies an AC voltage supplied from a power source (not shown) between the first cooling electrode 18 and the second cooling electrode 19. The voltage application unit 30 applies a voltage at which corona discharge occurs between the first cooling electrode 18 and the second cooling electrode 19 and does not cause a spark. The first cooling electrode 18 is grounded.

  The concave lens 31 collimates the light emitted from the light source device 252. The first integrator lens 32 and the second integrator lens 33 have a plurality of lens elements arranged in an array. The first integrator lens 32 divides the light flux from the concave lens 31 into a plurality of parts. Each lens element of the first integrator lens 32 condenses the light beam from the concave lens 31 in the vicinity of the lens element of the second integrator lens 33. The lens element of the second integrator lens 33 forms an image of the lens element of the first integrator lens 32 on the spatial light modulator.

  The light that has passed through the two integrator lenses 32 and 33 is converted into linearly polarized light in a specific vibration direction by the polarization conversion element 34. The superimposing lens 35 superimposes the image of each lens element of the first integrator lens 32 on the spatial light modulator. The first integrator lens 32, the second integrator lens 33, and the superimposing lens 35 make the light intensity distribution from the light source device 252 uniform on the spatial light modulator. Light from the superimposing lens 35 enters the first dichroic mirror 36. The first dichroic mirror 36 reflects R light and transmits G light and B light. The R light incident on the first dichroic mirror 36 has its optical path bent by reflection at the first dichroic mirror 36 and the reflection mirror 37, and is incident on the R light field lens 38R. The R light field lens 38R collimates the R light from the reflection mirror 37 and makes it incident on the R light spatial light modulator 39R.

  The spatial light modulator 39R for R light is a spatial light modulator that modulates R light according to an image signal, and is a transmissive liquid crystal display device. A liquid crystal panel (not shown) provided in the R light spatial light modulator 39R encloses a liquid crystal layer for modulating light according to an image signal between two transparent substrates. The R light modulated by the R light spatial light modulator 39R is incident on the cross dichroic prism 40 which is a color synthesis optical system.

  The G light and B light transmitted through the first dichroic mirror 36 enter the second dichroic mirror 41. The second dichroic mirror 41 reflects G light and transmits B light. The G light incident on the second dichroic mirror 41 has its optical path bent due to reflection by the second dichroic mirror 41, and enters the G light field lens 38G. The G light field lens 38G collimates the G light from the second dichroic mirror 41 and makes it incident on the G light spatial light modulator 39G. The G light spatial light modulation device 39G is a spatial light modulation device that modulates G light according to an image signal, and is a transmissive liquid crystal display device. The G light modulated by the G light spatial light modulator 39G is incident on a different surface of the cross dichroic prism 40 from the surface on which the R light is incident.

  The B light transmitted through the second dichroic mirror 41 is transmitted through the relay lens 42, and then the optical path is bent by reflection at the reflection mirror 43. The B light from the reflection mirror 43 further passes through the relay lens 44, and then the optical path is bent by reflection by the reflection mirror 45, and enters the B light field lens 38B. Since the optical path of the B light is longer than the optical path of the R light and the optical path of the G light, relay lenses 42 and 44 are provided in the optical path of the B light in order to make the illumination magnification in the spatial light modulator equal to that of other color lights. The relay optical system to be used is adopted.

  The B light field lens 38B collimates the B light from the reflection mirror 45 and makes it incident on the B light spatial light modulator 39B. The B light spatial light modulation device 39B is a spatial light modulation device that modulates B light according to an image signal, and is a transmissive liquid crystal display device. The B light modulated by the B light spatial light modulator 39B is incident on a surface of the cross dichroic prism 40 different from the surface on which the R light is incident and the surface on which the G light is incident.

  The cross dichroic prism 40 has two dichroic films 46 and 47 that are substantially orthogonal to each other. The first dichroic film 46 reflects R light and transmits G light and B light. The second dichroic film 47 reflects B light and transmits R light and G light. The cross dichroic prism 40 combines R light, G light, and B light incident from different directions and emits the light toward the projection lens 48. The projection lens 48 projects the light combined by the cross dichroic prism 40 toward the screen.

  By using the light source device 252 that can effectively cool the light emitting unit while suppressing the complexity of the structure and the problem of noise, the projector 1 can stably and efficiently display a bright image with a simple configuration. It becomes possible to do. Further, when the state shown in FIG. 3 is set to the upright state, if the inverted state is defined as the inverted state, when the light source device 252 is used in the inverted state, the upper side of the arc tube 11 is Covered with a sub-reflector 13. In this inverted state, heat tends to be trapped between the light emitting unit 15 and the sub-reflecting surface 13a, but the air between the light emitting unit 15 and the sub-reflecting mirror 13 is caused to flow by the ion wind, so that the light emitting unit 15 is effective. Therefore, the projector 1 can be stably operated while suppressing the occurrence of problems due to poor cooling. Moreover, since the creeping discharge can be used by arranging the first cooling electrode 18 and the second cooling electrode 19 so as to sandwich the sub-reflecting mirror 13 which is an insulator, the AC voltage supplied from the power source is changed to DC. The voltage can be applied without being converted. Therefore, it is possible to reduce costs by reducing the number of components that convert voltage.

  The light source device used in the projector 1 is not limited to the light source device 252 described in the first embodiment, and the light source device 252 described in the second embodiment or the light source device 302 described in the third embodiment may be used.

  The projector 1 is not limited to the case where a transmissive liquid crystal display device is used as the spatial light modulation device. As the spatial light modulator, a reflective liquid crystal display (Liquid Crystal On Silicon; LCOS), DMD (Digital Micromirror Device), GLV (Grating Light Valve), or the like may be used. The projector 1 is not limited to a configuration including a spatial light modulator for each color light. The projector 1 may be configured to modulate two or three or more color lights with one spatial light modulator. The projector 1 is not limited to using a spatial light modulation device. The projector 1 may be a slide projector that uses a slide having image information.

  Further, the shapes of the first cooling electrode and the second cooling electrode are not limited to the shapes described in the above-described embodiments. The shape of the first cooling electrode and the second cooling electrode may be any shape that can generate an ion wind by creeping discharge, and various shapes can be adopted.

  As described above, the light source device according to the present invention is suitable for use in a projector.

DESCRIPTION OF SYMBOLS 1 Projector, 3, 4 Arc electrode, 11 Light emission tube, 12 Main reflection mirror, 12a Main reflection surface, 13 Sub reflection mirror, 13a Sub reflection surface, 15 Light emission part, 16 2nd sealing part, 17 1st sealing , 18 First cooling electrode (first electrode), 18c Discharge part, 19 Second cooling electrode (second electrode), 19c Discharge part, 20 Sub-reflective part, 21 Insulating film, 23 Stretched part (first stretched) Part), 23a aperture, 27 fixing part, 30 voltage application part, 31 concave lens, 32 first integrator lens, 33 second integrator lens, 34 polarization conversion element, 35 superimposing lens, 36 first dichroic mirror, 37 reflection mirror, 38R Field lens for R light, field lens for 38G G light, field lens for 38B B light, spatial light modulation device for 39R R light, 39G G light Spatial light modulator for 39B, spatial light modulator for B light, 40 cross dichroic prism, 41 second dichroic mirror, 42 relay lens, 43 reflection mirror, 44 relay lens, 45 reflection mirror, 46 first dichroic film, 47 first 2 dichroic film, 48 projection lens, 252, 302 light source device, 253 stretching section (second stretching section), 255 third cooling electrode (third electrode), 255c discharging section, 256 fourth cooling electrode (fourth electrode) ) 256c Discharge part, 312 Main reflector, 313 Sub reflector, 313a Sub reflector, 320 Sub reflector, 323 Extender, 327 Adhering part, 330 Aperture, AX central axis, P, Q, R arrow

Claims (8)

An arc tube comprising: a light emitting unit that emits light; and a first sealing unit that is integrally provided on one side of the light emitting unit;
A sub-reflecting part that covers a part of the periphery of the light-emitting part and has a sub-reflecting surface that reflects light emitted from the light-emitting part; and a first extending part that covers the first sealing part. A sub-reflector,
A main reflecting mirror that reflects light emitted from the light emitting unit and light reflected by the sub-reflecting surface;
A first electrode disposed on the side opposite to the arc tube side with respect to the sub-reflecting mirror;
A second electrode disposed between the first sealing portion and the first extending portion;
Have
The first electrode is arranged so as to be shifted to the light emitting unit side with respect to the second electrode,
A light source device characterized in that an ion wind is generated by applying a voltage between the first electrode and the second electrode, and the air between the sub-reflecting surface and the light emitting unit can flow.   The light source device according to claim 1, wherein the first electrode is covered with an insulating layer.   An opening penetrating the surface on the arc tube side and the opposite surface is formed in the first extending portion at a position farther from the light emitting portion than the second electrode. Item 3. The light source device according to Item 1 or 2.   The light source device according to claim 1, wherein the first electrode extends from the first extending portion to a back surface of the sub-reflecting surface. The main reflecting mirror has substantially the same shape as a curved surface obtained by cutting a rotating curved surface obtained by rotating a predetermined curve around a central axis at a predetermined surface,
5. The light source device according to claim 1, wherein the sub-reflecting mirror covers a side opposite to the side where the main reflecting mirror is provided with respect to the light emitting unit. The arc tube includes a second sealing portion integrally provided on the other side of the light emitting portion,
The sub-reflecting mirror includes a second extending portion that covers the second sealing portion,
A third electrode disposed between the sub-reflecting mirror and the arc tube;
A fourth electrode disposed on the opposite side of the arc tube side with respect to the second extending portion,
The third electrode is arranged so as to be shifted to the light emitting unit side with respect to the fourth electrode,
2. An ion wind is generated by applying a voltage between the third electrode and the fourth electrode, and the air between the sub-reflecting surface and the light emitting part can flow. The light source device according to any one of? The main reflecting mirror has substantially the same shape as a rotating curved surface obtained by rotating a predetermined curve around a central axis,
The light source device according to claim 1, wherein the sub-reflecting mirror covers an irradiated surface side with respect to the light emitting unit. A light source device according to any one of claims 1 to 7,
A voltage application unit for applying an alternating voltage between the first electrode and the second electrode;
And a spatial light modulator that modulates light emitted from the light source device in accordance with an image signal.

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