JP2012195200A - Light source device and projector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device that can reduce effects of an acoustic resonance phenomenon.SOLUTION: A light source device 100 includes: a discharge lamp 10 having a first electrode 16 and a second electrode 18; a discharge lamp drive section 20 for supplying an AC current to the first electrode 16 and the second electrode 18 to drive the discharge lamp 10; and an ultrasonic wave generation section 30 for generating a second ultrasonic wave W2 having the opposite phase to a first ultrasonic wave W1 generated by an acoustic resonance phenomenon of the discharge lamp 10. A tip portion 16a of the first electrode 16 and a tip portion 18a of the second electrode 18 are arranged in a discharge space 14 of the discharge lamp 10. The ultrasonic wave generation section 30 has: a detection section for detecting the first ultrasonic wave W1; an arithmetic section for calculating a waveform having the opposite phase to the waveform of the first ultrasonic wave W1 from the detection result of the detection section; and a radiation section for generating the second ultrasonic wave W2 according to the arithmetic result of the arithmetic section, and radiating the second ultrasonic wave W2 to at least one of the tip portion 16a of the first electrode 16 and the tip portion 18a of the second electrode 18.

Description

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

  As a light source for a projector or the like, a discharge lamp (discharge lamp) such as a high-pressure mercury lamp or a metal halide lamp is generally used. In these discharge lamps, for example, when the lighting frequency is set to a high frequency of 10 kHz or more, an acoustic resonance phenomenon may occur. When an acoustic resonance phenomenon occurs in a discharge lamp, the electrode vibrates and adversely affects the performance as illumination, or the electrode may be destroyed.

  As a light source device that can reduce the influence of this acoustic resonance phenomenon, for example, Patent Document 1 discloses a light source device in which the lighting frequency of a discharge lamp is controlled in consideration of a frequency change characteristic that causes an acoustic resonance phenomenon. .

JP 2008-84782 A

  An object of some aspects of the present invention is to provide a light source device that can reduce the influence of an acoustic resonance phenomenon. Another object of some aspects of the present invention is to provide a projector including the above-described light source device.

The light source device according to the present invention includes:
A discharge lamp having an arc tube having a discharge space in which a discharge medium is enclosed, a first electrode and a second electrode;
A discharge lamp driving unit for supplying an alternating current to the first electrode and the second electrode to drive the discharge lamp;
An ultrasonic generator for generating a second ultrasonic wave having a phase opposite to the first ultrasonic wave generated by the acoustic resonance phenomenon of the discharge lamp;
Including
The tip of the first electrode and the tip of the second electrode are arranged in the discharge space of the discharge lamp,
The ultrasonic generator is
A detection unit for detecting the first ultrasonic wave;
From the detection result of the detection unit, a calculation unit that calculates a waveform having an opposite phase to the waveform of the first ultrasonic wave,
An irradiation unit that generates the second ultrasonic wave based on a calculation result of the calculation unit, and irradiates at least one of a tip part of the first electrode and a tip part of the second electrode;
Have

  According to such a light source device, the first ultrasonic wave generation unit irradiates the tip of the electrode with the second ultrasonic wave having the opposite phase to the first ultrasonic wave generated by the acoustic resonance phenomenon of the discharge lamp. Ultrasound can be attenuated. Therefore, the influence of the acoustic resonance phenomenon can be reduced.

In the light source device according to the present invention,
Two irradiation units are provided,
The first irradiation unit of the two irradiation units irradiates the tip of the first electrode with the second ultrasonic wave,
The 2nd irradiation part of the two said irradiation parts may irradiate the said 2nd ultrasonic wave to the front-end | tip part of the said 2nd electrode.

  According to such a light source device, since the ultrasonic wave generation unit includes the two irradiation units, it is possible to efficiently irradiate the tip portion of each electrode with the second ultrasonic wave.

In the light source device according to the present invention,
The frequency of the alternating current may be 10 kHz or more and 10 MHz or less.

The projector according to the present invention is
A light source device according to the present invention;
A light modulation device that modulates light emitted from the light source device according to image information;
A projection device for projecting an image formed by the light modulation device;
including.

  According to such a projector, since the light source device according to the present invention is included, a good image can be obtained.

The figure for demonstrating the light source device which concerns on 1st Embodiment. The figure for demonstrating the discharge lamp drive device of the light source device which concerns on 1st Embodiment. The figure for demonstrating the ultrasonic generator of the light source device which concerns on 1st Embodiment. The figure for demonstrating the ultrasonic generator of the light source device which concerns on a 1st modification. The figure for demonstrating the light source device which concerns on a 2nd modification. The figure which shows typically the projector which concerns on 2nd Embodiment.

  DESCRIPTION OF EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The embodiments described below do not unduly limit the contents of the present invention described in the claims. In addition, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. First embodiment 1.1. Configuration of Light Source Device First, the configuration of the light source device according to the present embodiment will be described with reference to the drawings. FIG. 1 is a diagram for explaining a light source device 100 according to the present embodiment. Note that FIG. 1 shows a cross-sectional view of the discharge lamp 10 and the reflector 40.

  As shown in FIG. 1, the light source device 100 includes a discharge lamp 10, a discharge lamp drive device (discharge lamp drive unit) 20, and an ultrasonic generator 30. The light source device 100 can further include a reflector 40.

  As shown in FIG. 1, the discharge lamp 10 includes an arc tube 12, a discharge space 14, a first electrode 16, and a second electrode 18.

  The arc tube 12 has a bar shape extending along the irradiation direction D from the first end 2 to the second end 4. That is, the central axis AX of the arc tube 12 extends along the irradiation direction D. The material of the arc tube 12 is a translucent material such as quartz glass, for example. A central portion of the arc tube 12 swells in a spherical shape, and a discharge space 14 is formed therein. The discharge space 14 is filled with a light emitting substance such as mercury or a metal halogen compound and a gas such as a rare gas or a halogen gas. These are discharge media for generating a discharge between a first electrode and a second electrode described later.

  The first electrode 16 is disposed on the first end 2 side of the arc tube 12, and the second electrode 18 is disposed on the second end 4 side of the arc tube 12. The shape of these electrodes 16 and 18 is a rod shape extending along the central axis AX of the arc tube 12. Further, two electrodes 16 and 18 protrude from the arc tube 12 in the discharge space 14. In the discharge space 14, tip portions (discharge ends) 16a and 18a of the electrodes 16 and 18 are arranged to face each other with a predetermined distance. In addition, the material of these electrodes 16 and 18 is metals, such as tungsten, for example.

  The first electrode 16 and the second electrode 18 are connected to the discharge lamp driving device 20. The discharge lamp driving device 20 supplies an alternating current to these electrodes 16 and 18. As a result, arc discharge occurs between the two electrodes 16 and 18. Light (discharge light) generated by the arc discharge is radiated in all directions from the discharge position between the two electrodes 16 and 18. The discharge lamp 10 is an arc discharge type discharge lamp such as a high-pressure mercury lamp, a metal halide lamp, or a xenon lamp.

  A reflector 40 is fixed to the first end 2 of the discharge lamp 10. The shape of the reflecting surface (surface on the discharge lamp 10 side) of the reflector 40 is, for example, a spheroid shape. The reflector 40 reflects the discharge light in the irradiation direction D. In addition, as a shape of the reflective surface of the reflector 40, not only a rotation ellipse shape but various shapes which reflect a discharge light toward the irradiation direction D are employable. For example, a rotating parabolic shape may be adopted as the shape of the reflecting surface of the reflector 40. In this case, the reflector 40 can convert the discharge light into light along the central axis AX of the arc tube 12.

  The discharge lamp driving device 20 drives the discharge lamp 10 by supplying an alternating current to the electrodes 16 and 18. The frequency of the alternating current supplied to the electrodes 16 and 18 by the discharge lamp driving device 20 is, for example, 10 kHz or more and 10 MHz or less. That is, the lighting frequency of the discharge lamp 10 is 10 kHz or more and 10 MHz or less.

  FIG. 2 is a diagram for explaining the configuration of the discharge lamp driving device 20. As shown in FIG. 2, the discharge lamp driving device 20 includes a power control unit 22, a polarity reversing unit 24, and a control unit 26.

  The power control unit 22 generates driving power to be supplied to the discharge lamp 10. The power control unit 22 includes, for example, a down chopper circuit that receives a DC power supply 50 and steps down the input voltage of the DC power supply 50 to output a DC current Id.

  The polarity inversion unit 24 receives the direct current Id output from the power control unit 22 and generates and outputs an alternating current I having an arbitrary frequency by inverting the polarity at a given timing. This alternating current I is supplied to the electrodes 16 and 18 of the discharge lamp 10 shown in FIG. The waveform of the alternating current I is, for example, a sine wave. The waveform of the alternating current I is not limited as long as it is a current whose magnitude and direction periodically change with time, and may be a rectangular wave or a triangular wave, for example. The polarity inversion unit 24 includes, for example, an inverter bridge circuit (full bridge circuit).

  The control unit 26 controls the current value, frequency, and the like of the alternating current I by controlling the power control unit 22 and the polarity reversing unit 24. The control unit 26 performs current control for controlling the current value of the direct current Id with respect to the power control unit 22. In addition, the control unit 26 performs polarity reversal control for controlling the frequency and the like of the alternating current I with respect to the polarity reversing unit 24 at the timing of polarity reversal of the alternating current I.

  In addition, the control unit 26 may receive a lighting command that instructs to turn on the discharge lamp 10 or a turn-off command that instructs to turn off the discharge lamp 10.

  The control unit 26 may be realized by a dedicated circuit and perform the above-described control. The control unit 26 may function as a computer by a CPU (Central Processing Unit) executing a control program stored in a storage unit or the like, and may perform various controls of these processes. That is, the control unit 26 may be configured to function as a current control unit that controls the power control unit 22 and a polarity reversal control unit that controls the polarity reversing unit 24 according to a control program.

  As shown in FIG. 1, the ultrasonic generator (ultrasonic generator) 30 is an ultrasonic wave (second ultrasonic wave) having a phase opposite to that of the ultrasonic wave (first ultrasonic wave) W1 generated by the acoustic resonance phenomenon of the discharge lamp 10. A sound wave (W2) is generated to irradiate the tip portion 16a of the first electrode 16 and the tip portion 18a of the second electrode 18. Thereby, the ultrasonic wave W1 generated by the acoustic resonance phenomenon is attenuated. The ultrasonic generator 30 is disposed outside the reflector 40.

  FIG. 3 is a diagram for explaining the configuration of the ultrasonic generator 30. As illustrated in FIG. 3, the ultrasonic generator 30 includes a detection unit 32, a calculation unit 34, and an irradiation unit 36.

  The detection unit 32 detects the ultrasonic wave W <b> 1 generated by the acoustic resonance phenomenon of the discharge lamp 10. The detection unit 32 includes, for example, an ultrasonic detection element, and can detect the ultrasonic wave W <b> 1 propagating in the air using the ultrasonic detection element. As the ultrasonic detection element, for example, a known ultrasonic detection element using a piezoelectric element or the like can be used. For example, the detection unit 32 detects the phase, amplitude, frequency, and the like of the ultrasonic wave W1. The detection unit 32 outputs detection result information 32 d that is information based on the detection result to the calculation unit 34.

  The computing unit 34 performs computation based on the detection result information 32d. The calculation unit 34 calculates a waveform having a phase opposite to the waveform of the ultrasonic wave W <b> 1 from the detection result of the detection unit 32. Further, the calculation unit 34 calculates an amplitude value having a magnitude that can attenuate the ultrasonic wave W <b> 1 from the detection result of the detection unit 32. This amplitude value is determined in consideration of how much the ultrasonic wave W1 is attenuated. For example, the calculation unit 34 calculates an amplitude value that is equal to or smaller than the amplitude of the waveform of the ultrasonic wave W1. The calculation unit 34 outputs waveform information 34d based on the calculation result to the irradiation unit 36. For example, the calculation unit 34 functions as a computer when the CPU executes a control program stored in a storage unit or the like, and performs these processes.

  The irradiation unit 36 generates an ultrasonic wave W2 based on the waveform information 34d. The irradiation unit 36 irradiates the distal end portion 16 a of the first electrode 16 and the distal end portion 18 a of the second electrode 18 with this ultrasonic wave W2. The ultrasonic wave W2 has the same frequency as the ultrasonic wave W1 generated by the acoustic resonance phenomenon, and has an opposite phase. The amplitude of the ultrasonic wave W2 is not particularly limited as long as the ultrasonic wave W1 can be attenuated, and is, for example, equal to or smaller than the amplitude of the ultrasonic wave W1. The irradiation unit 36 is a known ultrasonic generator using a piezoelectric element or the like, for example.

  Here, the irradiation unit 36 radiates the ultrasonic wave W2 to the distal end portion 16a of the first electrode 16 and the distal end portion 18a of the second electrode 18, but the ultrasonic wave W2 is applied only to the distal end portion 16a of the first electrode 16. Irradiation may be performed, or only the tip 18 a of the second electrode 18 may be irradiated with the ultrasonic wave W <b> 2.

  Although the case where the ultrasonic wave W2 has the opposite phase to the ultrasonic wave W1 has been described here, the present invention is not limited to this, and any ultrasonic wave W2 that can attenuate the ultrasonic wave W1 may be used.

1.2. Operation of Light Source Device Next, the operation of the light source device 100 will be described with reference to FIGS.

  In the light source device 100, the discharge lamp driving device 20 supplies an alternating current I to the electrodes 16 and 18 of the discharge lamp 10 to drive the discharge lamp 10. By supplying the alternating current I to the electrodes 16 and 18, the polarity of each electrode 16 and 18 can be repeated alternately. Thereby, it can suppress that the temperature of one electrode continues high state compared with the temperature of the other electrode. The frequency of the alternating current I is, for example, 10 kHz or more and 10 MHz or less. Therefore, the lighting frequency of the discharge lamp 10 is 10 kHz or more and 10 MHz or less.

  Thus, when the lighting frequency of the discharge lamp 10 is set to a relatively high frequency, an acoustic resonance phenomenon may occur in the discharge lamp 10. When an acoustic resonance phenomenon occurs in the discharge lamp 10, an ultrasonic wave W <b> 1 is generated using the tip portions 16 a and 18 a of the electrodes 16 and 18 as a generation source.

  In the light source device 100, when this ultrasonic wave W1 is generated, the ultrasonic generator 30 generates an ultrasonic wave W2 having a phase opposite to that of the ultrasonic wave W1, and the ultrasonic wave W2 is applied to the tip portions 16a and 18a of the electrodes 16 and 18. Irradiate. Specifically, the ultrasonic generator 30 first detects the frequency, phase, and amplitude of the ultrasonic wave W <b> 1 by the detection unit 32. Next, the calculation unit 34 calculates a waveform having a phase opposite to that of the ultrasonic wave W <b> 1 from the detection result of the detection unit 32. Next, the irradiation unit 36 generates an ultrasonic wave W2 having a phase opposite to that of the ultrasonic wave W1 from the calculation result of the calculation unit 34, and irradiates the tip portions 16a and 18a of the electrodes 16 and 18 with the ultrasonic wave W2.

  Thus, the ultrasonic wave generator 30 irradiates the ultrasonic waves W2 to the tip portions 16a and 18a of the electrodes 16 and 18, thereby attenuating the ultrasonic wave W1 generated by the acoustic resonance phenomenon.

  The light source device 100 has the following features, for example.

  According to the light source device 100, the ultrasonic wave generation device 30 irradiates the tip portions 16 a and 18 a of the electrodes 16 and 18 with ultrasonic waves W2 having a phase opposite to the ultrasonic wave W1 generated by the acoustic resonance phenomenon of the discharge lamp 10. Thus, the ultrasonic wave W1 can be attenuated. Therefore, the influence of the acoustic resonance phenomenon can be reduced. When an acoustic resonance phenomenon occurs in a discharge lamp, the electrode vibrates and adversely affects the performance as illumination, or the electrode may be destroyed. According to the light source device 100, since the influence of the acoustic resonance phenomenon can be reduced, such a problem can be prevented.

  According to the light source device 100, since the amplitude of the ultrasonic wave W2 generated by the ultrasonic wave generation device 30 can be controlled, the attenuation rate of the ultrasonic wave W1 generated by the acoustic resonance phenomenon can be controlled. As a result, the blackening phenomenon of the discharge lamp 10 can be suppressed while reducing the adverse effects of the acoustic resonance phenomenon, and the lifetime can be increased and the output can be increased. This will be described in detail below.

  When the discharge lamp is driven, the tip of the electrode evaporates, and this evaporated electrode material may adhere to the inner wall of the arc tube. This is called the blackening phenomenon of the discharge lamp. When the blackening phenomenon occurs in the discharge lamp, problems such as a shortened life and a decrease in output occur. Here, when the ultrasonic wave W1 is generated by the acoustic resonance phenomenon in the discharge lamp, the evaporated electrode material swings, and the electrode material becomes difficult to adhere to the inner wall of the arc tube (cleaning effect). That is, the blackening phenomenon can be suppressed by the ultrasonic wave W1 generated by the acoustic resonance phenomenon.

  According to the light source device 100, as described above, the attenuation rate of the ultrasonic wave W1 generated by the acoustic resonance phenomenon can be controlled. Therefore, for example, the ultrasonic wave W1 can be attenuated to the extent that the electrodes 16 and 18 of the discharge lamp 10 do not vibrate, that is, the adverse effect due to the acoustic resonance phenomenon does not occur without extinguishing the ultrasonic wave W1. Thereby, while reducing the adverse effect of the acoustic resonance phenomenon, the blackening phenomenon of the discharge lamp 10 can be suppressed, and the life and output can be increased.

1.3. Next, a light source device according to a modification of the present embodiment will be described with reference to the drawings. Hereinafter, in the light source device according to the modification of the present embodiment, members having the same functions as those of the constituent members of the light source device 100 according to the present embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

(1) First Modification First, a light source device according to a first modification will be described. FIG. 4 is a diagram for explaining the ultrasonic generator 30 of the light source device according to the first modification.

  In the example of the light source device 100, as shown in FIG. 3, the number of the irradiation units 36 of the ultrasonic generator 30 is one. On the other hand, in the light source device according to the first modification, as shown in FIG. 4, the number of irradiation units of the ultrasonic generator 30 is two (first irradiation unit 36a and second irradiation unit 36b).

  The calculation unit 34 outputs the waveform information 34d based on the calculation result to the first irradiation unit 36a and the second irradiation unit 36b. The 1st irradiation part 36a irradiates the ultrasonic wave W2 to the front-end | tip part 16a of the 1st electrode 16 based on the waveform information 34d. The 2nd irradiation part 36b irradiates the ultrasonic wave W2 to the front-end | tip part 18a of the 2nd electrode 18 based on the waveform information 34d. Thus, since the ultrasonic generator 30 has the two irradiation parts 36a and 36b, the front-end | tip parts 16a and 18a of each electrode 16 and 18 can be efficiently irradiated with the ultrasonic wave W2.

(2) Second Modification Next, a light source device according to a second modification will be described. FIG. 5 is a diagram for explaining a light source device 200 according to a second modification. FIG. 5 shows a cross-sectional view of the discharge lamp 10 and the reflector 40.

  In the example of the light source device 100, as shown in FIG. On the other hand, in the light source device 200 according to the second modified example, as shown in FIG. 5, there are two ultrasonic generators (first ultrasonic generator 30a and second ultrasonic generator 30b).

  The first ultrasonic generator 30a detects the ultrasonic wave W1 generated from the distal end portion 16a of the first electrode 16, and irradiates the ultrasonic wave W2 to the distal end portion 16a of the first electrode 16. The second ultrasonic generator 30b detects the ultrasonic wave W1 generated from the front end portion 18a of the second electrode 18, and irradiates the front end portion 18a of the second electrode 18 with the ultrasonic wave W2.

  According to the light source device 200, by having the two ultrasonic generators 30a and 30b, the ultrasonic wave W1 can be detected and irradiated with the ultrasonic wave W2 for each of the tips 16a and 18a of the electrodes 16 and 18, respectively. it can. Therefore, the ultrasonic wave W1 generated by the acoustic resonance phenomenon can be attenuated efficiently.

2. Second Embodiment Next, a projector 1000 according to the present embodiment will be described with reference to the drawings. FIG. 6 is a diagram schematically showing the projector 1000. In FIG. 6, for convenience, the illustrations of the casings constituting the discharge lamp driving device 20, the ultrasonic generator 30, and the projector 1000 are omitted.

  The projector 1000 is a front projection type projector that projects light onto a screen (not shown) and views an image by observing light reflected on the screen.

  As shown in FIG. 6, the projector 1000 includes a light source device 100, a collimating lens 102, an illumination optical system 110, a color separation optical system 120, three light modulation devices 130R, 130G, and 130B, and a cross dichroic prism. 140 and a projection lens (projection device) 150.

  The projector 1000 includes a light source device (for example, the light source device 100) according to the present invention. The light source device 100 emits light including red (R) light, green (G) light, and blue (B) light. Light from the light source device 100 passes through the collimating lens 102 and enters the illumination optical system 110. The collimating lens 102 collimates the light from the light source device 100. The collimating lens 102 is, for example, a concave lens.

  The illumination optical system 110 makes the illuminance of light from the light source device 100 uniform in the light modulation devices 130R, 130G, and 130B. The illumination optical system 110 aligns the polarization direction of the light from the light source device 100 in one direction. This is because the light from the light source device 100 is effectively used by the light modulation devices 130R, 130G, and 130B.

  The illumination optical system 110 includes a first integrator lens 112, a second integrator lens 114, a polarization conversion element 116, and a superimposing lens 118.

  The first integrator lens 112 and the second integrator lens 114 have a plurality of lens elements arranged in an array. The first integrator lens 112 divides the light flux from the collimating lens 102 into a plurality of parts. Each lens element of the first integrator lens 112 condenses the light beam from the collimating lens 102 in the vicinity of the lens element of the second integrator lens 114. The lens element of the second integrator lens 114 forms an image of the lens element of the first integrator lens 112 on the light modulation device.

  The light that has passed through the two integrator lenses 112 and 114 is converted into linearly polarized light in a specific vibration direction by the polarization conversion element 116. The superimposing lens 118 superimposes the image of each lens element of the first integrator lens 112 on the light modulation device. The first integrator lens 112, the second integrator lens 114, and the superimposing lens 118 make the light intensity distribution from the light source device 100 uniform on the light modulation device. The light from the superimposing lens 118 enters the color separation optical system 120 (first dichroic mirror 121).

  The color separation optical system 120 separates incident light into three color lights of red (R), green (G), and blue (B). The color separation optical system 120 includes a first dichroic mirror 121, reflection mirrors 122, 126, and 128, field lenses 123R, 123G, and 123B, a second dichroic mirror 124, and relay lenses 125 and 127. Yes.

  The first dichroic mirror 121 reflects R light and transmits G light and B light. The R light incident on the first dichroic mirror 121 has its optical path bent by reflection at the first dichroic mirror 121 and the reflection mirror 122, and enters the R light field lens 123R. The R light field lens 123R collimates the R light from the reflection mirror 122 and makes it incident on the R light light modulation device 130R.

  The G light and B light transmitted through the first dichroic mirror 121 are incident on the second dichroic mirror 124. The second dichroic mirror 124 reflects G light and transmits B light. The optical path of the G light incident on the second dichroic mirror 124 is bent by reflection by the second dichroic mirror 124 and enters the G light field lens 123G. The G light field lens 123G collimates the G light from the second dichroic mirror 124 and makes it incident on the G light modulator 130G.

  The B light transmitted through the second dichroic mirror 124 is transmitted through the relay lens 125, and then the optical path is bent by reflection at the reflection mirror 126. The B light from the reflection mirror 126 further passes through the relay lens 127, and then the optical path is bent by reflection by the reflection mirror 128, and enters the B light field lens 123B. 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 125 and 127 are used in the optical path of the B light in order to make the illumination magnification in the light modulation device equal to that of other color lights. A relay optical system is adopted.

  The R light modulation device 130R is a spatial light modulation device that modulates R light according to image information, and is a transmissive liquid crystal display device. The liquid crystal panel provided in the R light light modulation device 130R encloses a liquid crystal layer for modulating light according to image information between two transparent substrates. The R light modulated by the R light modulator 130R enters the cross dichroic prism 140, which is a color synthesis optical system.

  The light modulator 130G for G light is a spatial light modulator that modulates G light according to image information, and is a transmissive liquid crystal display device. The G light modulated by the G light modulator 130G is incident on a different surface of the cross dichroic prism 140 from the surface on which the R light is incident.

  The light modulation device 130B for B light is a spatial light modulation device that modulates B light according to image information, and is a transmissive liquid crystal display device. The B light modulated by the B light modulator 130B is incident on a surface of the cross dichroic prism 140 that is 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 140 includes two dichroic films 142 and 144 that are substantially orthogonal to each other. The first dichroic film 142 reflects R light and transmits G light and B light. The second dichroic film 144 reflects B light and transmits R light and G light. The cross dichroic prism 140 combines the R light, G light, and B light incident from different directions and emits the light toward the projection lens 150. The projection lens 150 projects the light combined by the cross dichroic prism 140 toward the screen.

  Since the projector 1000 includes the light source device 100 that can reduce the influence of the acoustic resonance phenomenon, a good image can be obtained.

  The projector 1000 is not limited to the case where a transmissive liquid crystal display device is used as the light modulation device. As the light modulation device, a reflective liquid crystal display device (Liquid Crystal On Silicon; LCOS), a DMD (Digital Micromirror Device), a GLV (Grating Light Valve), or the like may be used. The projector 1000 is not limited to a configuration including a light modulation device for each color light. The projector 1000 may be configured to modulate two or three or more color lights with one light modulation device. The projector 1000 is not limited to the case where a light modulation device is used. The projector 1000 may be a slide projector that uses a slide having image information.

  The present invention includes configurations that are substantially the same as the configurations described in the embodiments (for example, configurations that have the same functions, methods, and results, or configurations that have the same objects and effects). In addition, the invention includes a configuration in which a non-essential part of the configuration described in the embodiment is replaced. In addition, the present invention includes a configuration that exhibits the same operational effects as the configuration described in the embodiment or a configuration that can achieve the same object. Further, the invention includes a configuration in which a known technique is added to the configuration described in the embodiment.

W1 first ultrasonic wave, W2 second ultrasonic wave, AX central axis, D irradiation direction,
2 first end, 4 second end, 10 discharge lamp, 12 arc tube, 14 discharge space,
16 first electrode, 16a tip, 18 second electrode, 18a tip,
20 discharge lamp driving device, 22 power control unit, 24 polarity inversion unit, 26 control unit,
30 ultrasonic generator, 30a first ultrasonic generator, 30b second ultrasonic generator,
32 detection unit, 34 calculation unit, 36 irradiation unit, 36a first irradiation unit,
36b 2nd irradiation part, 40 reflector, 50 DC power supply, 100,200 light source device,
102 collimating lens, 110 illumination optical system, 112 first integrator lens,
114 second integrator lens, 116 polarization conversion element, 118 superposition lens,
120 color separation optical system, 121 first dichroic mirror,
122, 126, 128 reflection mirror, 123R R light field lens,
123G G light field lens, 123B B light field lens,
124 Second dichroic mirror, 125, 127 relay lens,
130R R light modulation device, 130G G light modulation device,
130B light modulator for B light, 140 cross dichroic prism,
142 First dichroic film, 144 Second dichroic film, 150 projection lens, 1000 projector

Claims (4)

A discharge lamp having an arc tube having a discharge space in which a discharge medium is enclosed, a first electrode and a second electrode;
A discharge lamp driving unit for supplying an alternating current to the first electrode and the second electrode to drive the discharge lamp;
An ultrasonic generator for generating a second ultrasonic wave having a phase opposite to the first ultrasonic wave generated by the acoustic resonance phenomenon of the discharge lamp;
Including
The tip of the first electrode and the tip of the second electrode are arranged in the discharge space of the discharge lamp,
The ultrasonic generator is
A detection unit for detecting the first ultrasonic wave;
From the detection result of the detection unit, a calculation unit that calculates a waveform having an opposite phase to the waveform of the first ultrasonic wave,
An irradiation unit that generates the second ultrasonic wave based on a calculation result of the calculation unit, and irradiates at least one of a tip part of the first electrode and a tip part of the second electrode;
A light source device characterized by comprising: Two irradiation units are provided,
The first irradiation unit of the two irradiation units irradiates the tip of the first electrode with the second ultrasonic wave,
2. The light source device according to claim 1, wherein a second irradiating unit of the two irradiating units irradiates the tip of the second electrode with the second ultrasonic wave.   The light source device according to claim 1, wherein the frequency of the alternating current is 10 kHz or more and 10 MHz or less. The light source device according to any one of claims 1 to 3,
A light modulation device that modulates light emitted from the light source device according to image information;
A projection device for projecting an image formed by the light modulation device;
Including a projector.

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