JP2011003379A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device enabling appropriate temperature adjustment of an arc tube with a simplified structure with restrained generation of noises.SOLUTION: The light source device 2 is provided with an arc tube 11 consisting of a light-emitting part 15 irradiating light and a second sealing part 16 integrally fitted to one side of the light-emitting part 15 and a first sealing part 17 integrally fitted to the other side of the light-emitting part 15, a sub reflecting mirror 13 covering a part of the periphery of the light-emitting part 15 and equipped with a sub reflecting face 13a reflecting the light irradiated from the light-emitting part, a main reflecting mirror 12 equipped with a main reflecting face 12a for reflecting the light irradiated from the light-emitting part 15 and light reflected at the sub reflecting face 13a, a first electrode 18 arranged between the sub reflecting mirror 13 and the light-emitting part 15, and a second electrode 19 arranged at a position of generating ion wind by impressing voltage between itself and the first electrode 18 and circulating air between the sub reflecting face 13a and the light-emitting part 15.

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 has been proposed in which a sub-reflecting mirror that covers a part of the arc tube is provided separately from the reflector as the main reflecting mirror (see, for example, 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 covers an arc tube including a light emitting unit that emits light and a part of the periphery of the light emitting unit, and reflects light emitted from the light emitting unit. A sub-reflecting mirror having a sub-reflecting surface, a main reflecting mirror having a main reflecting surface that reflects light emitted from the light-emitting unit and light reflected by the sub-reflecting mirror, and between the sub-reflecting mirror and the light-emitting unit A second electrode disposed at a position where an ion wind is generated by applying a voltage between the first electrode disposed and the first electrode, and the air between the sub-reflecting surface and the light emitting unit flows; Have

  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 a wind generated by corona discharge generated when a predetermined voltage is applied between the first electrode and the second electrode. When a predetermined voltage is applied between the first electrode and the second electrode, air molecules are ionized by corona discharge in the vicinity of the electrode connected to the anode side, toward the electrode connected to the cathode side. Moving. The wind generated by the movement of the ionized air is called ion wind. Corona discharge is likely to occur when the tip of the electrode is sharp.

  Moreover, as a preferable aspect of the present invention, it is desirable that the first electrode is disposed so as to be shifted to the light emitting unit side with respect to the second electrode. By connecting the first electrode to the anode side and the second electrode to the cathode side, an ion wind from the first electrode to the second electrode is generated, and more reliably between the sub-reflection surface and the light emitting unit. The air can be made to flow. Thereby, the temperature control of the arc tube can be performed more appropriately.

  As a preferred aspect of the present invention, the arc tube includes a first sealing portion integrally provided on one side of the light emitting portion and a second sealing portion integrally provided on the other side of the light emitting portion. It is preferable to further include an extending portion that is integrally formed with the sub-reflecting mirror and covers the first sealing portion, and the second electrode is disposed between the extending portion and the first sealing portion. Even when the sub-reflecting mirror has an extending portion, the air between the light-emitting portion and the sub-reflecting surface can be flowed by the ion wind from the second electrode toward the first electrode. Temperature control can be performed appropriately.

  As a preferred embodiment of the present invention, it is desirable that the second electrode has a needle shape. An ion wind can be generated by generating a corona discharge between the first electrode and the tip of the second electrode having a needle shape.

  Moreover, as a preferable aspect of the present invention, it is desirable to have a plurality of second electrodes. By having a plurality of second electrodes, ion wind can be generated at a plurality of locations, so that the air between the sub-reflecting surface and the light emitting portion can be largely flowed to cool the light emitting portion more effectively. .

  Moreover, as a preferable aspect of the present invention, it is desirable that the plurality of second electrodes be arranged such that the distance between the tip of the second electrode and the first electrode is different for each of the plurality of second electrodes. By making the distance between the tip of the second electrode and the first electrode different for each of the plurality of second electrodes, it is possible to generate ion winds having different states for each second electrode. For example, the flow of air between the arc tube and the sub-reflection surface can be controlled by generating ion winds having different strengths for each second electrode. By controlling the flow of air, it is possible to increase the cooling efficiency by greatly flowing the air around the portion of the light emitting portion that is likely to become high temperature.

  Moreover, as a preferable aspect of the present invention, the second electrode is desirably formed by applying a conductive material to the sub-reflecting mirror. Since the second electrode can be formed by a relatively simple operation of applying a conductive material, the manufacturing cost of the light source device can be reduced. Also, if the second electrode is too thin, it may be destroyed when a voltage is applied. On the other hand, if the second electrode is formed by coating, the second electrode can have a certain thickness by increasing the number of times of coating. Therefore, it is possible to form the second electrode that has a certain thickness and is not easily destroyed when a voltage is applied.

  As a preferred embodiment of the present invention, it is desirable that the second electrode is formed by depositing a conductive material on the sub-reflecting mirror. The sub-reflecting surface of the sub-reflecting mirror may be formed by depositing a metal material. If the second electrode is also formed by vapor-depositing a metal material that is a conductive material, the sub-reflecting surface and the second electrode can be formed in one process, and the manufacturing process of the light source device is reduced and manufactured. Cost can be reduced.

  Moreover, as a preferable aspect of the present invention, it is desirable that the second electrode is formed by attaching a sheet-like conductive material to the sub-reflecting mirror. Since the second electrode can be formed by a relatively simple operation of attaching a sheet-like conductive material, the manufacturing cost of the light source device can be reduced. Also, if the second electrode is too thin, it may be destroyed when a voltage is applied. On the other hand, by using a sheet-like conductive material having a certain thickness, it is possible to form a second electrode that is not easily destroyed when a voltage is applied.

  Moreover, as a preferable aspect of the present invention, it is desirable that the edge of the second electrode on the first electrode side has a saw blade shape having a plurality of irregularities in plan view. The saw blade shape with multiple irregularities allows ionic wind to be generated from the top of the multiple irregularities, so that the air between the sub-reflecting surface and the light emitting part is greatly flowed to cool the light emitting part more effectively can do.

  As a preferred embodiment of the present invention, the sawtooth shape of the second electrode is desirably a non-uniform shape so that the distance between the top of the unevenness and the first electrode is different for each of the multiple unevennesses. By making the distance between the top of the unevenness and the first electrode different for each of the plurality of tops, it is possible to generate ion winds having different states for each top. For example, the flow of air between the arc tube and the sub-reflecting surface can be controlled by generating ion winds having different strengths for each top. By controlling the flow of air, it is possible to increase the cooling efficiency by greatly flowing the air around the portion of the light emitting portion that is likely to become high temperature. Moreover, since the positional relationship between the tops can be defined in advance by forming the saw blade shape on the second electrode, it is not necessary to adjust the positions of the tops when assembling the light source device. Thereby, the assembling property of the light source device can be improved and the manufacturing cost can be suppressed.

  As a preferred embodiment of the present invention, the first electrode is desirably a reflective film that reflects light by being formed by depositing a conductive material on the sub-reflective surface. By using the reflective film that reflects light on the sub-reflecting surface as the first electrode, it is not necessary to separately provide the first electrode, and the cost can be reduced by reducing the number of components.

  Further, the projector according to the present invention includes the light source device, a voltage applying unit that applies a 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.

  Moreover, as a preferable aspect of the present invention, it is desirable that the voltage application unit applies a voltage that causes corona discharge between the first electrode and the second electrode and does not cause spark. The projector can be stably operated by suppressing the destruction of the electrode due to sparks and the influence on other electronic devices.

1 is an external perspective view showing a schematic configuration of a light source device according to Embodiment 1 of the present invention. The disassembled perspective view of a light source device. The cross-sectional view of a light source device. FIG. 6 is a cross-sectional view of a light source device according to a first modification of the first embodiment. FIG. 6 is a cross-sectional view of a light source device according to a second modification of the first embodiment. FIG. 9 is a plan view of a sub-reflecting mirror included in a light source device according to Modification 3 of Example 1. The disassembled perspective view of the light source device which concerns on Example 2 of this invention. The top view of a sub reflector part. The disassembled perspective view of the light source device which concerns on Example 3 of this invention. The figure which shows the state which accumulated the masking sheet on the sub-reflection mirror. FIG. 10 is a diagram illustrating a schematic configuration of a projector according to a fourth embodiment of the 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 2 according to Embodiment 1 of the present invention. FIG. 2 is an exploded perspective view of the light source device 2 shown in FIG. FIG. 3 is a cross-sectional view of the light source device 2 shown in FIG. The light source device 2 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 2 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 2 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 2 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 2 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 portion 17 has a cylindrical shape and is provided on one side (rear side) of the light emitting portion 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 present 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 2 can be made thinner than the light source device using the reflecting mirror whose spheroid 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 surface 13 a that reflects the light emitted from the light emitting unit 15. 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 mirror 13 and the light emitting unit 15. The sub-reflecting mirror 13 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 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 sub-reflecting mirror 13 includes an extending portion 23 that covers a part of the first sealing portion 17 on the rear side portion. The extension part 23 is bonded to the fixing part 27, whereby the sub-reflecting mirror 13 in the light source device 2 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 first cooling electrode 18 and the second cooling electrode 19 are for causing an ionic wind by applying a voltage between the electrodes 18 and 19. The first cooling electrode 18 is formed by bending a plate-like metal member having a rectangular shape in plan view in accordance with the shape of the extending portion 23. The first cooling electrode 18 is disposed between the first sealing portion 17 of the arc tube 11 and the extending portion 23 of the sub-reflecting mirror 13 and in the vicinity of the sub-reflecting surface 13a. Here, since the first cooling electrode 18 is disposed between the first sealing portion 17 and the extending portion 23, the light reflected by the sub-reflecting surface 13a is not easily blocked by the first cooling electrode 18, A decrease in light utilization efficiency can be suppressed.

  The second cooling electrode 19 is formed of a needle-like metal member. The second cooling electrode 19 has a sharp tip 19 a portion between the first sealing portion 17 of the arc tube 11 and the extending portion 23 of the sub-reflecting mirror 13, and more than the first cooling electrode 18. It arrange | positions so that it may become a position shifted to the back side. With this arrangement, the first cooling electrode 18 is arranged at a position shifted from the tip 19 a of the second cooling electrode 19 toward the light emitting unit 15.

  The first cooling electrode 18 is connected to the cathode side of a voltage application unit (not shown), the second cooling electrode 19 is connected to the anode side of the voltage application unit, and a voltage is applied between the electrodes 18 and 19 by the voltage application unit. As a result, corona discharge can be caused between the electrodes 18 and 19. Air molecules ionized near the tip 19a of the second cooling electrode 19 by corona discharge are attracted to the first cooling electrode 18 and move. 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 desirably a voltage that does not cause a spark between the electrodes 18 and 19. For example, when the distance between the tip 19 a of the second cooling electrode 19 and the first cooling electrode 18 is about 2 mm, a voltage of 2 to 3 kV is applied between the electrodes 18 and 19.

  By generating an ionic wind from the second cooling electrode 19 toward the first cooling electrode 18, an air flow along the arrow X is caused to flow between the light emitting portion 15 and the sub-reflecting surface 13 a. Can be made. 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, 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.

  FIG. 4 is a cross-sectional view of the light source device 2 according to the first modification of the first embodiment. In the first modification, the reflection film 13 b formed on the sub-reflection surface 13 a is used as the first cooling electrode 18. Specifically, the reflective film 13b is formed by vapor-depositing a metal that is a conductive material on the sub-reflecting surface 13a. Then, the reflective film 13b is connected to the cathode side of the voltage application unit.

  If a voltage is applied between the second cooling electrode 19 and the reflective film 13b, an ion wind from the second cooling electrode 19 toward the reflective film 13b can be generated. Thereby, since the air flow along the arrow Y can be caused to flow between the light emitting unit 15 and the sub-reflecting surface 13a, the light emitting unit 15 can be effectively cooled. In addition, since the reflection film 13b formed to reflect the light emitted from the light emitting unit 15 can be used as an electrode for generating an ion wind, the number of parts can be reduced compared to the case where a separate electrode is provided. Cost can be reduced.

  FIG. 5 is a cross-sectional view of the light source device 2 according to the second modification of the first embodiment. In the light source device 2 according to the second modification, the reflection film 13 b formed on the sub-reflecting mirror 13 is used as the first cooling electrode 18 as in the first modification. The sub-reflecting mirror 13 provided in the light source device 2 according to Modification 2 is not provided with an extending portion, and is provided with a fixing portion 13c on the opposite side of the sub-reflecting surface 13a. For example, if the light source device includes an explosion-proof cover that covers the lower side of the main reflector, the sub-reflector 13 can be fixed by fixing the explosion-proof cover with the fixing portion 13c.

  The second cooling electrode 19 is disposed in the vicinity of the rear end portion of the reflective film 13b. The second cooling electrode 19 is arranged so that the tip thereof is shifted rearward from the rear end of the reflective film 13b. In the second modification, the extension part is not provided in the sub-reflecting mirror 13, but as described above, the first cooling electrode 18 and the second cooling electrode 19 constitute the ions along the arrow Y. Wind can be generated to flow the air between the light emitting unit 15 and the sub-reflecting surface 13a. Thereby, effective cooling of the light emission part 15 is attained.

  FIG. 6 is a plan view of the sub-reflecting mirror 13 portion included in the light source device according to the third modification of the first embodiment. In the third modification, the first cooling electrode 18 is attached to the sub-reflecting mirror 13, and the rear portion is shaped to draw an arc. Even when the first cooling electrode 18 is formed in such a shape, the air between the light emitting portion and the sub-reflecting surface 13a is caused to flow by ion wind to effectively cool the light emitting portion 15. It can be carried out.

  FIG. 7 is an exploded perspective view of the light source device according to the second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals, and redundant description is omitted. In the second embodiment, the second cooling electrode 19 is composed of a plurality of needle-like metal members (hereinafter referred to as needle members).

  FIG. 8 is a plan view of the sub-reflecting mirror 13 portion provided in the light source device 102 shown in FIG. As shown in FIG. 8, since the second cooling electrode 19 is composed of a plurality of needle members, ion wind can be generated at a plurality of locations, and between the light emitting unit 15 and the sub-reflecting mirror 13. Air can flow more greatly. Thereby, the light emission part 15 can be cooled more effectively. Further, as shown in FIG. 8, the distance between the tip of the needle member constituting the second cooling electrode 19 and the first cooling electrode 18 is different for each needle member, and the voltage applied to each needle member is changed. By making it different, ion winds having different states can be generated for each first cooling electrode. For example, the flow of air between the light emitting unit 15 and the sub-reflecting mirror 13 can be controlled by generating ion winds having different strengths for each second cooling electrode 19. By controlling the flow of air, it is possible to increase the cooling efficiency by largely flowing the air around the portion (for example, the lowermost end) that tends to be high in the light emitting unit 15. Of course, the distances between the tips of all the needle members and the first cooling electrode 18 may be equal.

  FIG. 9 is an exploded perspective view of the light source device 152 according to the third embodiment of the present invention. The same parts as those in the above embodiment are denoted by the same reference numerals, and redundant description is omitted. In the third embodiment, the second cooling electrode 19 is composed of an aluminum sheet in which aluminum is formed in a sheet shape. The edge of the second cooling electrode 19 on the first cooling electrode 18 side in plan view has a saw-tooth shape with irregularities. For example, the second cooling electrode 19 having a saw blade shape is obtained by punching an aluminum sheet into a desired shape. The second cooling electrode 18 is attached to the extending portion 23 of the sub-reflecting mirror 13. When a voltage is applied between the first cooling electrode 18 and the second cooling electrode 19, an ion wind due to corona discharge is generated between the plurality of saw blade-shaped top portions 19 b and the first cooling electrode 18. . The air between the light emitting unit 15 and the sub-reflecting surface 13a is caused to flow by the ion wind, so that the light emitting unit 15 can be efficiently cooled.

  In addition, the saw blade shape of the second cooling electrode 19 is changed to a non-uniform shape by changing the interval between the top portions 19b and the size of the unevenness, and the distance from the first cooling electrode 18 is changed for each top portion 19b. The flow of air between the light emitting unit 15 and the sub-reflecting mirror 13 can also be controlled. For example, the flow of air between the light emitting unit 15 and the sub-reflecting mirror 13 can be controlled by generating ion winds having different strengths for each second cooling electrode 19. By controlling the flow of air, it is possible to increase the cooling efficiency by largely flowing the air around the portion (for example, the lowermost end) that tends to be high in the light emitting unit 15.

  Further, in the case of the second cooling electrode 19 having a saw blade shape, since the positional relationship between the top portions 19b is determined in advance, the adjustment of the distance from the first cooling electrode 18 for each top portion 19b when the light source device 152 is assembled. Is no longer necessary. Thereby, the assembling property of the light source device 152 can be improved and the manufacturing cost can be suppressed.

  The edge of the second cooling electrode 19 is not limited to the case where the edge is formed in a saw blade shape having a plurality of top portions 19b. For example, you may form in the mountain shape provided with one top part. In the third embodiment, the sheet-like second cooling electrode 19 is formed by attaching an aluminum sheet to the extending portion 23 of the sub-reflecting mirror 13, but is not limited thereto. For example, the second cooling electrode may be formed by evaporating a conductive metal material on the extending portion 23 of the sub-reflecting mirror 13.

  FIG. 10 is a view showing a state in which a masking sheet is superimposed on the sub-reflecting mirror 13. When the metal material is vapor-deposited on the sub-reflecting mirror 13, the second cooling electrode having a desired shape is formed on the extending portion 23 by stacking the masking sheet 28 that has been punched into a desired shape on the extending portion 23. be able to. Here, if the reflecting film 13b formed on the sub-reflecting surface 13a of the sub-reflecting mirror 13 is also formed by vapor deposition of metal, the reflecting film 13b and the second cooling electrode 19 can be formed at the same time. Cost reduction by reduction can be achieved. Further, if the reflective film 13b is used as the first cooling electrode, it is possible to further reduce the cost by reducing the number of manufacturing steps.

  Further, as shown in FIG. 10, the second cooling electrode having a desired shape is stretched by applying a conductive material, for example, a conductive paint containing a metal, with the masking sheet superimposed on the sub-reflector 13. It may be formed on the portion 23. The second cooling electrode can be formed by a relatively simple operation of applying the conductive paint. If the second cooling electrode is too thin, the second cooling electrode may be destroyed when a voltage is applied. When the second cooling electrode is formed of an aluminum sheet or a conductive paint, it is easy to give the second cooling electrode a certain thickness by using a thick sheet material or by repeatedly applying it. By giving the second cooling long electrode a certain thickness, it is possible to provide a second cooling electrode that is not easily destroyed when a voltage is applied.

  FIG. 11 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 2 according to the first embodiment (see also FIGS. 1 and 2). The light source device 2 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 2. The voltage application unit 30 converts an AC voltage supplied from a power source (not shown) into a DC voltage. The first cooling electrode 18 of the light source device 2 is connected to the cathode of the voltage application unit 30, and the second cooling electrode 19 is connected to the anode of the voltage application unit 30. The voltage application unit 30 applies a DC voltage converted 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 concave lens 31 collimates the light emitted from the light source device 2. 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 2 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 2 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, when the inverted state is defined as the inverted state, when the light source device 2 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. However, the air between the light emitting unit and the sub-reflecting mirror is caused to flow by ion wind to effectively cool the light emitting unit. Therefore, it is possible to stably operate the projector 1 while suppressing the occurrence of problems due to poor cooling.

  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 corona discharge, and various shapes can be employed.

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

AX Central axis, X arrow, Y arrow, 1 projector, 2, 102, 152 light source device, 3, 4 arc electrode, 11 arc tube, 12 main reflecting mirror, 12a main reflecting surface, 13 sub reflecting mirror, 13a sub reflecting Surface, 13b reflective film, 13c fixing part, 15 light emitting part, 16 second sealing part, 17 first sealing part, 18 first cooling electrode (first electrode), 19 second cooling electrode (second electrode) ), 19a Tip, 19b Top, 23 Stretched portion, 27 Adhering portion, 28 Masking sheet, 30 Voltage applying portion, 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 R light field lens, 38G G field lens, 38B light beam Yield lens, spatial light modulation device for 39R R light, spatial light modulation device for 39G G light, spatial light modulation device for 39B B light, 40 cross dichroic prism, 41 second dichroic mirror, 42 relay lens, 43 reflection mirror, 44 relay Lens, 45 Reflecting mirror, 46 First dichroic film, 47 Second dichroic film, 48 Projection lens

Claims (14)

An arc tube including a light emitting unit for emitting light;
A sub-reflecting mirror that covers a part of the periphery of the light-emitting unit and includes a sub-reflecting surface that reflects the light emitted from the light-emitting unit;
A main reflecting mirror including a main reflecting surface that reflects light emitted from the light emitting unit and light reflected by the sub-reflecting mirror;
A first electrode disposed between the sub-reflecting mirror and the light emitting unit;
A second electrode disposed at a position where an ion wind is generated by applying a voltage between the first electrode and air flows between the sub-reflecting surface and the light-emitting portion. A light source device.   2. The light source device according to claim 1, wherein the first electrode is arranged so as to be shifted to the light emitting unit side with respect to the second electrode. The arc tube includes a first sealing portion integrally provided on one side of the light emitting portion, and a second sealing portion integrally provided on the other side of the light emitting portion,
An extending portion that is integrally formed with the sub-reflecting mirror and covers the first sealing portion;
The light source device according to claim 2, wherein the second electrode is disposed between the extending portion and the first sealing portion.   The light source device according to claim 1, wherein the second electrode has a needle shape.   The light source device according to claim 4, comprising a plurality of the second electrodes.   The light source according to claim 5, wherein the plurality of second electrodes are arranged such that a distance between a tip of the second electrode and the first electrode is different for each of the plurality of second electrodes. apparatus.   The light source device according to claim 1, wherein the second electrode is formed by applying a conductive material to the sub-reflecting mirror.   The light source device according to claim 1, wherein the second electrode is formed by depositing a conductive material on the sub-reflecting mirror.   The light source device according to claim 1, wherein the second electrode is formed by attaching a sheet-like conductive material to the sub-reflecting mirror.   10. The light source device according to claim 7, wherein an edge of the second electrode on the first electrode side has a saw blade shape having a plurality of irregularities in a plan view.   11. The light source according to claim 10, wherein the sawtooth shape of the second electrode is a non-uniform shape such that a distance between the top of the unevenness and the first electrode is different for each of the plurality of unevennesses. apparatus.   The light source device according to claim 1, wherein the first electrode is a reflective film that is formed by depositing a conductive material on the sub-reflection surface and reflects light. . The light source device according to any one of claims 1 to 12,
A voltage application unit for applying a 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.   14. The projector according to claim 13, wherein the voltage application unit applies a voltage at which corona discharge occurs between the first electrode and the second electrode and does not cause a spark.

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