JP6044803B2 - Projector and projector system - Google Patents

Description

  The present invention relates to a projector.

  Projectors using discharge lamps such as high-pressure mercury lamps and metal halide lamps have been put into practical use. As such a projector, for example, Patent Document 1 discloses a projector having means for changing the intensity of a light source in accordance with a color separation means in synchronization with a video signal. However, Patent Document 2 describes a problem that if the intensity of the light source is simply changed, the electrodes of the discharge lamp are significantly consumed.

  In recent years, projectors that output stereoscopic images using discharge lamps such as high-pressure mercury lamps and metal halide lamps have been put into practical use.

  One of the three-dimensional video output methods is a method of switching the right-eye video and the left-eye video alternately and outputting them alternately (for example, an active shutter glasses method such as “XPAND beond cinema (trademark of X6D Limited)”) There is. In this method, using active shutter glasses synchronized with the video signal, the right-eye video is shown to the right eye and the left-eye video is shown to the left eye, so that the video is shown in three dimensions using the parallax of the left and right eyes. .

JP 2003-102030 A JP 2009-237302 A

  When three-dimensional images are projected by alternately outputting right-eye and left-eye images, the amount of light entering the right and left eyes is less than half compared to the case of projecting conventional planar images (two-dimensional images). It becomes. In addition, when a crosstalk occurs in which the right-eye video enters the left eye or the left-eye video enters the right eye, the video is not perceived as a three-dimensional image, so a period in which both active shutters are closed is required. Therefore, when a stereoscopic video is projected by a method of alternately outputting a right-eye video and a left-eye video, there is a problem that the video looks darker than when a conventional planar video is projected. In order to make the image look brighter, it may be possible to simply increase the driving power, but there are problems such as increasing the power consumption of the projector and promoting the deterioration of peripheral parts caused by increasing the driving power. .

  In order to make the image appear brighter, if the brightness of the discharge lamp is reduced while both active shutters are closed and the brightness of the discharge lamp is increased while either active shutter is open, the discharge lamp Since the temperature of the electrode of the discharge lamp is lowered during the period when the brightness of the lamp is lowered and the meltability of the electrode tip becomes insufficient, the electrode may be deformed. If the electrode is deformed, it may cause flicker. Therefore, special consideration is required to suppress the deformation of the electrode.

  The present invention has been made in view of the above problems. According to some aspects of the present invention, it is possible to provide a projector capable of projecting an image so as to appear bright while suppressing deformation of the electrodes.

  A projector according to the present invention is a projector that switches between a first video and a second video and outputs them alternately at a given switching timing, the discharge lamp including a first electrode and a second electrode, and the discharge lamp A discharge lamp driving unit that supplies a driving current for driving the discharge lamp to the discharge lamp, and a control unit that controls the discharge lamp driving unit, and a period between the switching timings that are temporally adjacent is a first period. And at the end of the second period, the control unit performs the first control in a first control period that continues at least between the switching timings that are temporally adjacent, and at least the switching timings that are temporally adjacent. The second control is performed during a second control period different from the first control period, and the absolute value of the drive current is set to the first period in the first control and the second control. Is controlled to be relatively small and relatively large in the second period, and in the first control, in the first control, an alternating current is used as the driving current in the first period. The discharge lamp driving unit is controlled so as to be supplied to the discharge lamp, and in the second period, energy given to the first electrode during the second period is given to the second electrode during the second period. A first control process is performed to control the discharge lamp drive unit so that the drive current that is greater than the generated energy is supplied to the discharge lamp. In the second control, in the first period, AC is used as the drive current. The discharge lamp driving unit is controlled to supply current to the discharge lamp, and in the second period, energy applied to the second electrode during the second period is changed to the first period during the second period. electrode The drive current becomes larger than the given energy performs a second control process for controlling the discharge lamp driving unit so as to supply to the discharge lamp.

  According to the present invention, the energy given to the first electrode in the first control process and the second electrode in the second control process is increased, so that the meltability of the electrode is increased. Therefore, deformation of the electrode can be suppressed.

  According to the present invention, the control unit controls the discharge lamp driving unit so that the absolute value of the driving current is relatively small in the first period and relatively large in the second period. A projector that can project the image so that it looks bright.

  In the projector, the control unit may perform the second control in a period that is at least a part of a period between the first control periods that are temporally adjacent to each other.

  Thereby, the thermal load balance between the first electrode and the second electrode of the discharge lamp can be maintained. Therefore, it can suppress that the electrode of a discharge lamp wears out unevenly.

  In this projector, the control unit performs a third control during a third control period that is continued at least between the switching timings adjacent in time and is different from the first control period and the second control period, In the third control, the discharge lamp driving unit is controlled such that the absolute value of the driving current is relatively small in the first period and relatively large in the second period, and the second The difference between the energy given to the first electrode and the energy given to the second electrode during two periods is smaller than that in the first control and the second control, and the driving current is supplied to the discharge lamp. As described above, at least one of the first control and the second control may be performed in a period between the third control periods that are temporally adjacent to each other by controlling the discharge lamp driving unit.

  As a result, adverse effects such as blackening due to excessive melting of the electrodes by the first control and the second control can be suppressed.

The projector includes a state detection unit that detects a deterioration state of the discharge lamp,
The controller may shorten the length of the third control period as the deterioration state progresses.

  The state detection unit, for example, as a value indicating the degree of the deterioration state, for example, the discharge lamp drive voltage, the discharge lamp drive voltage change over time, the discharge lamp light quantity, the discharge lamp light quantity change over time, the discharge lamp cumulative lighting time Etc. may be detected.

  As the deterioration state progresses, the meltability of the electrode decreases. Therefore, by shortening the length of the third control period as the deterioration state progresses, it is possible to improve the meltability of the electrode and suppress the deformation of the electrode.

  The projector includes a state detection unit that detects a deterioration state of the discharge lamp, and the control unit increases the length of the first control period and the second control period as the deterioration state progresses. May be.

  As the deterioration state progresses, the meltability of the electrode decreases. Therefore, by increasing the length of the first control period and the second control period as the deterioration state progresses, it is possible to improve the meltability of the electrode and suppress the deformation of the electrode.

  In the projector, in the first control process, the control unit controls the discharge lamp driving unit to supply the discharge lamp with a direct current in which the first electrode serves as an anode as the driving current. In the second control process, the discharge lamp driving unit may be controlled so that a DC current with the second electrode serving as an anode is supplied to the discharge lamp as the driving current.

  Thereby, a 1st control process and a 2nd control process are realizable by simple control.

  In the projector, in the first control process, the control unit has an AC current in which the time for the first electrode to be an anode in one cycle is longer than the time for the second electrode to be an anode as the drive current. The discharge lamp driving unit is controlled to supply the discharge lamp to the discharge lamp, and in the second control process, as the drive current, the time during which the second electrode occupies one cycle is the anode, The discharge lamp driving unit may be controlled so that an alternating current that is longer than the time for the anode is supplied to the discharge lamp.

  Thereby, a 1st control process and a 2nd control process are realizable by simple control.

  In the projector, in the first control process, the control unit includes a period in which an alternating current is supplied as the driving current, and a period in which a direct current with the first electrode serving as an anode is supplied to the discharge lamp. In the second control process, the period for supplying the alternating current as the driving current and the period for supplying the direct current with the second electrode serving as an anode to the discharge lamp are controlled. The discharge lamp driving unit may be controlled to include.

  Thereby, a 1st control process and a 2nd control process are realizable by simple control.

Explanatory drawing which shows the optical system of the projector 500 which concerns on 1st Embodiment. 4 is an explanatory diagram illustrating a configuration of a light source device 200. FIG. FIG. 3 is a diagram illustrating an example of a circuit configuration of the projector according to the first embodiment. The figure which shows an example of the circuit structure of the discharge lamp lighting device. The figure for demonstrating the other structural example of the control part. 6A to 6D are explanatory diagrams showing the relationship between the polarity of the drive current I supplied to the discharge lamp 90 and the electrode temperature. The figure for demonstrating a 1st period, a 2nd period, and switching timing. The figure for demonstrating the relationship between a switching timing, a 1st control period, and a 2nd control period. FIG. 9A is a timing chart showing a waveform example in the first control, and FIG. 9B is a timing chart showing a waveform example in the second control. FIG. 10A is a timing chart showing another waveform example in the first control, and FIG. 10B is a timing chart showing another waveform example in the second control. FIG. 11A is a timing chart showing another waveform example in the first control, and FIG. 11B is a timing chart showing another waveform example in the second control. The figure for demonstrating the relationship between a switching timing, a 1st control period, a 2nd control period, and a 3rd control period. The timing chart which shows the example of a waveform in 3rd control. 10 is a flowchart illustrating a control example of a projector according to a third embodiment. The figure which shows an example of the correspondence of a drive condition. The figure which shows an example of the correspondence of a drive condition.

  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. Also, not all of the configurations described below are essential constituent requirements of the present invention.

1. 1. Projector according to first embodiment 1-1. Optical System of Projector FIG. 1 is an explanatory diagram showing an optical system of a projector 500 according to the first embodiment. The projector 500 includes a light source device 200, a collimating lens 305, an illumination optical system 310, a color separation optical system 320, three liquid crystal light valves 330R, 330G, and 330B, a cross dichroic prism 340, and a projection optical system 350. And have.

  The light source device 200 includes a light source unit 210 and a discharge lamp lighting device 10. The light source unit 210 includes a main reflecting mirror 112, a sub reflecting mirror 50 (described later), and a discharge lamp 90. The discharge lamp lighting device 10 supplies power to the discharge lamp 90 to light the discharge lamp 90. The main reflecting mirror 112 reflects the light emitted from the discharge lamp 90 in the irradiation direction D. The irradiation direction D is parallel to the optical axis AX. Light from the light source unit 210 passes through the collimating lens 305 and enters the illumination optical system 310. The collimating lens 305 collimates the light from the light source unit 210.

  The illumination optical system 310 makes the illuminance of light from the light source device 200 uniform in the liquid crystal light valves 330R, 330G, and 330B. The illumination optical system 310 aligns the polarization direction of light from the light source device 200 in one direction. This is because the light from the light source device 200 is effectively used by the liquid crystal light valves 330R, 330G, and 330B. The light whose illuminance distribution and polarization direction are adjusted enters the color separation optical system 320. The color separation optical system 320 separates incident light into three color lights of red (R), green (G), and blue (B). The three color lights are respectively modulated by the liquid crystal light valves 330R, 330G, and 330B associated with the respective colors. The liquid crystal light valves 330R, 330G, and 330B include liquid crystal panels 560R, 560G, and 560B (described later) and polarizing plates (not shown) disposed on the light incident side and the emission side of the liquid crystal panels 560R, 560G, and 560B, respectively. . The modulated three color lights are combined by the cross dichroic prism 340. The combined light enters the projection optical system 350. The projection optical system 350 projects incident light onto a screen (not shown). Thereby, an image is displayed on the screen.

  Note that various well-known configurations can be adopted as the configurations of the collimating lens 305, the illumination optical system 310, the color separation optical system 320, the cross dichroic prism 340, and the projection optical system 350.

  FIG. 2 is an explanatory diagram showing the configuration of the light source device 200. The light source device 200 includes a light source unit 210 and a discharge lamp lighting device 10. In the drawing, a cross-sectional view of the light source unit 210 is shown. The light source unit 210 includes a main reflecting mirror 112, a discharge lamp 90, and a sub reflecting mirror 50.

  The shape of the discharge lamp 90 is a rod shape extending along the irradiation direction D from the first end 90e1 to the second end 90e2. The material of the discharge lamp 90 is a translucent material such as quartz glass, for example. A central portion of the discharge lamp 90 swells in a spherical shape, and a discharge space 91 is formed therein. The discharge space 91 is filled with a gas that is a discharge medium containing mercury, a rare gas, a metal halogen compound, and the like.

  The discharge lamp 90 includes a first electrode 92 and a second electrode 93. In the example shown in FIG. 2, the first electrode 92 and the second electrode 93 are provided so as to protrude into the discharge space 91. The first electrode 92 is disposed on the first end 90 e 1 side of the discharge space 91, and the second electrode 93 is disposed on the second end 90 e 2 side of the discharge space 91. The shape of the first electrode 92 and the second electrode 93 is a rod shape extending along the optical axis AX. In the discharge space 91, the electrode tip portions (also referred to as “discharge ends”) of the first electrode 92 and the second electrode 93 face each other with a predetermined distance therebetween. The material of the first electrode 92 and the second electrode 93 is, for example, a metal such as tungsten.

  A first terminal 536 is provided at the first end 90 e 1 of the discharge lamp 90. The first terminal 536 and the first electrode 92 are electrically connected by a conductive member 534 that passes through the inside of the discharge lamp 90. Similarly, a second terminal 546 is provided at the second end 90 e 2 of the discharge lamp 90. The second terminal 546 and the second electrode 93 are electrically connected by a conductive member 544 that passes through the inside of the discharge lamp 90. The material of the first terminal 536 and the second terminal 546 is, for example, a metal such as tungsten. Further, as each of the conductive members 534 and 544, for example, a molybdenum foil is used.

  The first terminal 536 and the second terminal 546 are connected to the discharge lamp lighting device 10. The discharge lamp lighting device 10 supplies a drive current for driving the discharge lamp 90 to the first terminal 536 and the second terminal 546. As a result, arc discharge occurs between the first electrode 92 and the second electrode 93. Light (discharge light) generated by the arc discharge is radiated in all directions from the discharge position, as indicated by the dashed arrows.

  The main reflecting mirror 112 is fixed to the first end 90 e 1 of the discharge lamp 90 by a fixing member 114. The shape of the reflecting surface (the surface on the discharge lamp 90 side) of the main reflecting mirror 112 is a spheroid shape. The main reflecting mirror 112 reflects the discharge light in the irradiation direction D. The shape of the reflecting surface of the main reflecting mirror 112 is not limited to the spheroid shape, and various shapes that reflect the discharge light toward the irradiation direction D can be employed. For example, a rotating parabolic shape may be adopted. In this case, the main reflecting mirror 112 can convert the discharge light into light substantially parallel to the optical axis AX. Therefore, the collimating lens 305 can be omitted.

The sub-reflecting mirror 50 is fixed to the second end 90 e 2 side of the discharge lamp 90 by a fixing member 522. The shape of the reflective surface (surface on the discharge lamp 90 side) of the sub-reflecting mirror 50 is a spherical shape that surrounds the second end 90e2 side of the discharge space 91. The sub-reflecting mirror 50 reflects the discharge light toward the main reflecting mirror 112. Thereby, the utilization efficiency of the light radiated | emitted from the discharge space 91 can be improved.

  As a material for the fixing members 114 and 522, any heat-resistant material (for example, an inorganic adhesive) that can withstand the heat generated by the discharge lamp 90 can be used. Further, the method of fixing the arrangement of the main reflecting mirror 112 and the sub-reflecting mirror 50 and the discharge lamp 90 is not limited to the method of fixing the main reflecting mirror 112 and the sub-reflecting mirror 50 to the discharge lamp 90, and any method can be used. It can be adopted. For example, the discharge lamp 90 and the main reflecting mirror 112 may be independently fixed to a housing (not shown) of the projector. The same applies to the sub-reflecting mirror 50.

1-2. Circuit Configuration of Projector FIG. 3 is a diagram illustrating an example of a circuit configuration of the projector according to the first embodiment. In addition to the optical system described above, the projector 500 includes an image signal conversion unit 510, a DC power supply device 80, a discharge lamp lighting device 10, a discharge lamp 90, liquid crystal panels 560R, 560G, 560B, an image processing device 570, a CPU ( Central Processing Unit) 580 may be included. Further, the projector system 400 including the projector 500 and the active shutter glasses 410 may be configured.

  The image signal converter 510 converts an externally input image signal 502 (such as a luminance-color difference signal or an analog RGB signal) into a digital RGB signal having a predetermined word length to generate image signals 512R, 512G, and 512B. This is supplied to the image processing device 570. In addition, the image signal conversion unit 510 receives the first video and the second video as the image signal 502 when a video signal in which the first video and the second video are alternately switched at a given switching timing is input. The synchronization signal 514 is supplied to the CPU 580 based on the switching timing.

  The image processing device 570 performs image processing on each of the three image signals 512R, 512G, and 512B, and supplies drive signals 572R, 572G, and 572B for driving the liquid crystal panels 560R, 560G, and 560B, respectively, to the liquid crystal panels 560R and 560G. 560B.

  The DC power supply device 80 converts an AC voltage supplied from an external AC power supply 600 into a constant DC voltage, and an image signal conversion unit on the secondary side of a transformer (not shown, but included in the DC power supply device 80). 510, a DC voltage is supplied to the image processing device 570 and the discharge lamp lighting device 10 on the primary side of the transformer.

  The discharge lamp lighting device 10 generates a high voltage between the electrodes of the discharge lamp 90 at the time of startup to cause a dielectric breakdown to form a discharge path, and thereafter supplies a driving current I for the discharge lamp 90 to maintain a discharge.

  The liquid crystal panels 560R, 560G, and 560B modulate the luminance of the color light incident on each liquid crystal panel via the optical system described above based on the drive signals 572R, 572G, and 572B, respectively.

  The CPU 580 controls the operation from the start of lighting of the projector to the turning off of the projector. For example, a lighting command or a lighting command may be output to the discharge lamp lighting device 10 via the communication signal 582. Further, the CPU 580 may receive lighting information of the discharge lamp 90 from the discharge lamp lighting device 10 via the communication signal 584. Further, based on the synchronization signal 514, the CPU 580 outputs a control signal 586 for controlling the active shutter glasses 410 in synchronization with the image signal 502 to the active shutter glasses 410 via wired or wireless communication means. Also good.

The active shutter glasses 410 may include a right shutter 412 and a left shutter 414. The right shutter 412 and the left shutter 414 are controlled to open and close based on a control signal 586. When the user wears the active shutter glasses 410, the right shutter 412 is closed, so that the visual field on the right eye side can be blocked. Further, when the user wears the active shutter glasses 410, the left shutter 414 is closed so that the visual field on the left eye side can be blocked. The right shutter 412 and the left shutter 414 may be configured with, for example, a liquid crystal shutter.

1-3. Configuration of Discharge Lamp Lighting Device FIG. 4 is a diagram illustrating an example of a circuit configuration of the discharge lamp lighting device 10.

  The discharge lamp lighting device 10 includes a power control circuit 20. The power control circuit 20 generates driving power to be supplied to the discharge lamp 90. In the first embodiment, the power control circuit 20 includes a down chopper circuit that receives a DC power supply 80 and steps down the input voltage to output a DC current Id.

  The power control circuit 20 can include a switch element 21, a diode 22, a coil 23, and a capacitor 24. The switch element 21 can be composed of, for example, a transistor. In the first embodiment, one end of the switch element 21 is connected to the positive voltage side of the DC power supply 80, and the other end is connected to the cathode terminal of the diode 22 and one end of the coil 23. One end of a capacitor 24 is connected to the other end of the coil 23, and the other end of the capacitor 24 is connected to the anode terminal of the diode 22 and the negative voltage side of the DC power supply 80. A current control signal is input to a control terminal of the switch element 21 from a control unit 40 (described later), and ON / OFF of the switch element 21 is controlled. For example, a PWM (Pulse Width Modulation) control signal may be used as the current control signal.

  Here, when the switch element 21 is turned ON, a current flows through the coil 23 and energy is stored in the coil 23. Thereafter, when the switch element 21 is turned OFF, the energy stored in the coil 23 is released through a path passing through the capacitor 24 and the diode 22. As a result, a direct current Id corresponding to the proportion of time during which the switch element 21 is turned on is generated.

  The discharge lamp lighting device 10 includes a polarity inversion circuit 30. The polarity inversion circuit 30 receives the direct current Id output from the power control circuit 20 and reverses the polarity at a given timing, so that the polarity inversion circuit 30 can be a direct current that lasts for a controlled time or has an arbitrary frequency. The drive current I is generated and output. In the first embodiment, the polarity inverting circuit 30 includes an inverter bridge circuit (full bridge circuit).

  The polarity inversion circuit 30 includes, for example, a first switch element 31, a second switch element 32, a third switch element 33, and a fourth switch element 34 configured by transistors, and the first switch element 31 connected in series. The switch element 31 and the second switch element 32, and the third switch element 33 and the fourth switch element 34 connected in series are connected in parallel to each other. The polarity inversion control signal is input from the control unit 40 to the control terminals of the first switch element 31, the second switch element 32, the third switch element 33, and the fourth switch element 34, respectively. Based on this, ON / OFF of the first switch element 31, the second switch element 32, the third switch element 33, and the fourth switch element 34 is controlled.

The polarity inversion circuit 30 repeats the ON / OFF operation of the first switch element 31 and the fourth switch element 34, and the second switch element 32 and the third switch element 33 alternately. The polarity of the direct current Id to be output is alternately inverted, and the common connection point between the first switch element 31 and the second switch element 32 and the common connection between the third switch element 33 and the fourth switch element 34. From the point, DC that lasts for a controlled time,
A drive current I that is an alternating current having a controlled frequency is generated and output.

  That is, when the first switch element 31 and the fourth switch element 34 are ON, the second switch element 32 and the third switch element 33 are turned OFF, and the first switch element 31 and the fourth switch element 34 are When the switch is OFF, the second switch element 32 and the third switch element 33 are controlled to be turned ON. Therefore, when the first switch element 31 and the fourth switch element 34 are ON, the drive current I flowing from the one end of the capacitor 24 in the order of the first switch element 31, the discharge lamp 90, and the fourth switch element 34 is generated. To do. In addition, when the second switch element 32 and the third switch element 33 are ON, a drive current I flowing from the one end of the capacitor 24 to the third switch element 33, the discharge lamp 90, and the second switch element 32 is generated. To do.

  In the first embodiment, the power control circuit 20 and the polarity inversion circuit 30 are combined to correspond to the discharge lamp driving unit 230. That is, the discharge lamp driving unit 230 supplies the driving current I for driving the discharge lamp 90 to the discharge lamp 90.

  The discharge lamp lighting device 10 includes a control unit 40. The control unit 40 controls the discharge lamp driving unit 230. In the example shown in FIG. 4, the control unit 40 controls the power control circuit 20 and the polarity inversion circuit 30 to determine the holding time during which the drive current I continues with the same polarity, the current value of the drive current I, the frequency, and the like. Control. The control unit 40 performs polarity reversal control for controlling the holding time for the drive current I to remain the same polarity, the frequency of the drive current I, and the like based on the polarity reversal timing of the drive current I with respect to the polarity reversal circuit 30. Further, the control unit 40 performs current control for controlling the current value of the output direct current Id to the power control circuit 20.

  The configuration of the control unit 40 is not particularly limited, but in the first embodiment, the control unit 40 includes a system controller 41, a power control circuit controller 42, and a polarity inversion circuit controller 43. Note that a part or all of the control unit 40 may be configured by a semiconductor integrated circuit.

  The system controller 41 controls the power control circuit 20 and the polarity reversing circuit 30 by controlling the power control circuit controller 42 and the polarity reversing circuit controller 43. The system controller 41 controls the power control circuit controller 42 and the polarity inversion circuit controller 43 based on the drive voltage Vla and the drive current I detected by the voltage detection unit 60 provided in the discharge lamp lighting device 10 described later. Good.

  In the first embodiment, the system controller 41 includes a storage unit 44. The storage unit 44 may be provided independently of the system controller 41.

  The system controller 41 may control the power control circuit 20 and the polarity inversion circuit 30 based on information stored in the storage unit 44. The storage unit 44 may store information on drive parameters such as a holding time during which the drive current I continues with the same polarity, a current value of the drive current I, a frequency, a waveform, and a modulation pattern.

  The power control circuit controller 42 controls the power control circuit 20 by outputting a current control signal to the power control circuit 20 based on the control signal from the system controller 41.

  The polarity inversion circuit controller 43 controls the polarity inversion circuit 30 by outputting a polarity inversion control signal to the polarity inversion circuit 30 based on the control signal from the system controller 41.

  Note that the control unit 40 can be realized by a dedicated circuit to perform the above-described control and various kinds of control of processing to be described later. For example, a control in which a CPU (Central Processing Unit) is stored in the storage unit 44 or the like. It is also possible to function as a computer by executing the program and to perform various controls of these processes. FIG. 5 is a diagram for explaining another configuration example of the control unit 40. As shown in FIG. 5, the control unit 40 is configured to function as a current control unit 40-1 that controls the power control circuit 20 and a polarity reversal control unit 40-2 that controls the polarity reversing circuit 30 according to a control program. May be.

  In the example shown in FIG. 4, the control unit 40 is configured as a part of the discharge lamp lighting device 10. However, the CPU 580 may be configured to perform a part of the function of the control unit 40. .

  The discharge lamp lighting device 10 may include an operation detection unit. The operation detection unit may include, for example, a voltage detection unit 60 that detects the drive voltage Vla of the discharge lamp 90 and outputs drive voltage information, and a current detection unit that detects the drive current I and outputs drive current information. In the present embodiment, the voltage detection unit 60 includes first and second resistors 61 and 62.

  The voltage detector 60 corresponds to the state detector in the present invention. That is, the state detection unit (voltage detection unit 60) detects the drive voltage Vla as a value representing the degree of deterioration of the electrode.

  In the first embodiment, the voltage detection unit 60 detects the drive voltage Vla in parallel with the discharge lamp 90 using the voltage divided by the first resistor 61 and the second resistor 62 connected in series. In the first embodiment, the current detection unit detects the drive current I based on the voltage generated in the third resistor 63 connected in series to the discharge lamp 90.

  The discharge lamp lighting device 10 may include an igniter circuit 70. The igniter circuit 70 operates only at the start of lighting of the discharge lamp 90. At the start of lighting of the discharge lamp 90, the igniter circuit 70 breaks down the insulation between the electrodes of the discharge lamp 90 (between the first electrode 92 and the second electrode 93). Is supplied between the electrodes of the discharge lamp 90 (between the first electrode 92 and the second electrode 93). In the first embodiment, the igniter circuit 70 is connected in parallel with the discharge lamp 90.

1-4. Relationship between Polarity of Driving Current and Electrode Temperature FIGS. 6A to 6D are explanatory diagrams showing the relationship between the polarity of the driving current I supplied to the discharge lamp 90 and the electrode temperature. 6A and 6B show the operating state of the first electrode 92 and the second electrode 93. FIG. In the drawing, the tip portions of the first electrode 92 and the second electrode 93 are shown. Protrusions 552p and 562p are provided at the tips of the first electrode 92 and the second electrode 93, respectively. The discharge generated between the first electrode 92 and the second electrode 93 is mainly generated between the protrusion 552p and the protrusion 562p. In this embodiment, the movement of the discharge position (arc position) in the first electrode 92 and the second electrode 93 can be suppressed as compared with the case where there is no protrusion. However, such protrusions may be omitted.

  FIG. 6A shows a first polarity state P1 in which the first electrode 92 operates as an anode and the second electrode 93 operates as a cathode. In the first polarity state P1, electrons move from the second electrode 93 (cathode) to the first electrode 92 (anode) by discharge. Electrons are emitted from the cathode (second electrode 93). Electrons emitted from the cathode (second electrode 93) collide with the tip of the anode (first electrode 92). Heat is generated by this collision, and the temperature of the tip (projection 552p) of the anode (first electrode 92) rises.

  FIG. 6B shows a second polarity state P2 in which the first electrode 92 operates as a cathode and the second electrode 93 operates as an anode. In the second polarity state P2, electrons move from the first electrode 92 to the second electrode 93, contrary to the first polarity state P1. As a result, the temperature of the tip (projection 562p) of the second electrode 93 rises.

  Thus, the temperature of the anode tends to be higher than that of the cathode. Here, the continued high state of the temperature of one electrode compared to the other electrode can cause various problems. For example, when the tip of the high temperature electrode melts excessively, unintended electrode deformation may occur. As a result, the arc length may deviate from an appropriate value. Moreover, when the melting | fusing of the front-end | tip of a low-temperature electrode is inadequate, the fine unevenness | corrugation produced at the front-end | tip may remain without melting. As a result, a so-called arc jump may occur (the arc position moves without being stable).

  As a technique for suppressing such inconvenience, AC driving in which the polarity of each electrode is repeatedly changed can be used. FIG. 6C is a timing chart showing an example of the drive current I supplied to the discharge lamp 90 (FIG. 2). The horizontal axis indicates time T, and the vertical axis indicates the current value of the drive current I. The drive current I indicates the current flowing through the discharge lamp 90. A positive value indicates the first polarity state P1, and a negative value indicates the second polarity state P2. In the example shown in FIG. 6C, a rectangular wave alternating current is used as the drive current I. In the example shown in FIG. 6C, the first polarity state P1 and the second polarity state P2 are alternately repeated. Here, the first polarity section Tp indicates the time that the first polarity state P1 continues, and the second polarity section Tn indicates the time that the second polarity state P2 continues. In the example shown in FIG. 6C, the average current value in the first polarity section Tp is Im1, and the average current value in the second polarity section Tn is -Im2. The frequency of the drive current I suitable for driving the discharge lamp 90 can be determined experimentally according to the characteristics of the discharge lamp 90 (for example, a value in the range of 30 Hz to 1 kHz is adopted). Other values Im1, −Im2, Tp, and Tn can be determined experimentally in the same manner.

  FIG. 6D is a timing chart showing the temperature change of the first electrode 92. The horizontal axis represents time T, and the vertical axis represents temperature H. In the first polarity state P1, the temperature H of the first electrode 92 increases, and in the second polarity state P2, the temperature H of the first electrode 92 decreases. Further, since the first polarity state P1 and the second polarity state P2 state are repeated, the temperature H periodically changes between the minimum value Hmin and the maximum value Hmax. Although illustration is omitted, the temperature of the second electrode 93 changes in a phase opposite to the temperature H of the first electrode 92. That is, in the first polarity state P1, the temperature of the second electrode 93 decreases, and in the second polarity state P2, the temperature of the second electrode 93 increases.

  In the first polarity state P1, the tip of the first electrode 92 (projection 552p) is melted, so that the tip of the first electrode 92 (projection 552p) is smooth. Thereby, the movement of the discharge position in the 1st electrode 92 can be suppressed. In addition, since the temperature at the tip of the second electrode 93 (projection 562p) falls, excessive melting of the second electrode 93 (projection 562p) is suppressed. Thereby, unintended electrode deformation can be suppressed. In the second polarity state P2, the positions of the first electrode 92 and the second electrode 93 are reversed. Therefore, by repeating the two states P1 and P2, problems in each of the first electrode 92 and the second electrode 93 can be suppressed.

  Here, when the waveform of the current I is symmetric, that is, when the waveform of the current I satisfies the condition “| Im1 | = | −Im2 |, Tp = Tn”, the first electrode 92 and the second electrode 93, the condition of the supplied power is the same. Therefore, if the first electrode 92 and the second electrode 93 have the same thermal conditions (ease of temperature rise and fall), the temperature difference between the first electrode 92 and the second electrode 93 is estimated to be small. Is done.

Further, if the electrode is heated too much over a wide range (an arc spot (a hot spot on the electrode surface accompanying arc discharge) becomes large), the shape of the electrode is destroyed due to excessive melting. On the other hand, if the electrode is too cold (the arc spot is small), the tip of the electrode cannot be melted sufficiently, and the tip cannot be returned smoothly, that is, the tip of the electrode is easily deformed. Therefore, when the uniform energy supply state is continued with respect to the electrode, the tip of the electrode (the protrusion 552p and the protrusion 562p) easily deforms into an unintended shape.

1-5. Example of Driving Current Control Next, a specific example of controlling the driving current I in the projector 500 according to the first embodiment will be described.

  FIG. 7 is a diagram for describing the first period, the second period, and the switching timing. FIG. 7 shows the contents of the drive signals 572R, 572G, and 572B, the opening / closing state of the right shutter 412, the opening / closing state of the left shutter 414, the first period and the second period, and the switching timing in order from the top. Yes. The horizontal axis in FIG. 7 is time. In the following, an example will be described in which the viewer is stereoscopically viewed with the first video and the second video as the left-eye video and the right-eye video, respectively.

  In the example shown in FIG. 7, the drive signals 572R, 572G, and 572B are the right-eye video as the first video from time t1 to time t3, and the right-eye as the second video from time t3 to time t5. The drive signal corresponds to the right-eye video as the first video from time t5 to time t7, and the right-eye video as the second video from time t7 to time t9. Therefore, in the example shown in FIG. 7, the projector 500 uses the time t1, the time t3, the time t5, the time t7, and the time t9 as switching timings, and the right-eye video as the first video and the right-eye video as the second video. And output alternately.

  The period between the temporally adjacent switching timings starts with the first period and ends with the second period. In the example illustrated in FIG. 7, for example, the period between the time t1 and the time t3 that is the switching timing starts with a first period from the time t1 to the time t2, and is between the time t2 and the time t3. Ends in the second period. The same applies to a period sandwiched between time t3 and time t5 serving as switching timing, a period sandwiched between time t5 and time t7 serving as switching timing, and a period sandwiched between time t7 and time t9 serving as switching timing. In the example shown in FIG. 7, the length of the first period is the same as the length of the second period, but the length of the first period and the length of the second period are appropriately set as necessary. Can be set. In addition, a third period may exist between the first period and the second period. In the third period, control different from the control of the drive current I in the first period and the second period described later may be performed.

  The right shutter 412 is in an open state during at least a part of the period in which the drive signals 572R, 572G, and 572B corresponding to the right-eye video as the first video are input to the liquid crystal panels 560R, 560G, and 560B. In the example shown in FIG. 7, the right shutter 412 is in a closed state from time t1 to time t2, and is in an open state from time t2 to time t3. In the example shown in FIG. 7, the right shutter 412 is set to the time during the period in which the drive signals 572R, 572G, and 572B corresponding to the right-eye video as the second video are input to the liquid crystal panels 560R, 560G, and 560B. It begins to close from t3, finishes closing between time t3 and time t4, and is closed from time t4 to time t5. The change in the open / close state of the right shutter 412 from time t5 to time t9 is the same as the change in the open / close state from time t1 to time t5.

The left shutter 414 is in an open state during at least a part of the period in which the drive signals 572R, 572G, and 572B corresponding to the right-eye video as the second video are input to the liquid crystal panels 560R, 560G, and 560B. In the example shown in FIG. 7, the left shutter 414 is in a closed state from time t3 to time t4, and is in an open state from time t4 to time t5. In the example shown in FIG. 7, the left shutter 414 is set to the time during the period in which the drive signals 572R, 572G, 572B corresponding to the right-eye video as the first video are input to the liquid crystal panels 560R, 560G, 560B. It starts to close from t1, finishes closing between time t1 and time t2, and is closed from time t2 to time t3. The change in the open / close state of the left shutter 414 between the time t5 and the time t9 is the same as the change in the open / close state between the time t1 and the time t5.

  In the example shown in FIG. 7, the right shutter 412 is closed during a period in which the drive signals 572R, 572G, and 572B corresponding to the right-eye video as the first video are input to the liquid crystal panels 560R, 560G, and 560B. The period corresponds to the first period, and the period in which the right shutter 412 is open corresponds to the second period. In the example shown in FIG. 7, the left shutter 414 is closed during the period in which the drive signals 572R, 572G, and 572B corresponding to the right-eye video as the second video are input to the liquid crystal panels 560R, 560G, and 560B. The period during which the left shutter 414 is open corresponds to the first period, and the period during which the left shutter 414 is open corresponds to the second period. In the example shown in FIG. 7, in the first period, there is a period in which both the right shutter 412 and the left shutter 414 are closed.

  FIG. 8 is a diagram for explaining the relationship between the switching timing and the first control period and the second control period. The horizontal axis in FIG. 8 represents time. Times t11 to t27 are switching timings. The first control period is a period during which the control unit 40 performs the first control, and the second control period is a period during which the control unit 40 performs the second control.

  In the projector 500 according to the first embodiment, the control unit 40 performs the first control in a first control period that continues for at least a period sandwiched between temporally adjacent switching timings, and at least at temporally adjacent switching timings. The second control is performed in a second control period that continues during the sandwiched period and is different from the first control period. In the example shown in FIG. 8, the first control and the second control are continued for a period four times as long as the period sandwiched between temporally adjacent switching timings. For example, in FIG. 8, the first first control period continues during a period from time t11 as the switching timing to time t15 as the switching timing. In FIG. 8, the first second control period continues during a period from time t15 as the switching timing to time t19 as the switching timing. The length of time for which the first control and the second control are continued can be set as appropriate according to the specifications of the discharge lamp 90.

  FIG. 9A is a timing chart showing a waveform example in the first control, and FIG. 9B is a timing chart showing a waveform example in the second control. 9A and 9B, the horizontal axis represents time, and the vertical axis represents the current value of the drive current I. 9A and 9B, the driving current I when the first electrode 92 is an anode is a positive value, and the driving current I when the second electrode 93 is an anode is a negative value. Represent. In the following description, the polarity of the drive current I when the first electrode 92 is an anode is expressed as a first polarity, and the polarity of the drive current I when the second electrode 93 is an anode is expressed as a second polarity. .

  In the projector 500 according to the first embodiment, in the first control and the second control, the control unit 40 causes the absolute value of the drive current I to be relatively smaller in the first period than in the second period. In the period, the discharge lamp driving unit 230 is controlled to be relatively larger than the first period.

  In the example shown in FIG. 9A, the absolute value of the current value of the drive current I is I1 in the first period and I2 in the second period. In the example shown in FIG. 9A, I1 <I2. Therefore, in the first control, the absolute value of the drive current I is relatively small in the first period and relatively large in the second period.

  Similarly, in the example shown in FIG. 9B, the absolute value of the current value of the drive current I is I1 in the first period and I2 in the second period. In the example shown in FIG. 9B, I1 <I2. Therefore, in the second control, the absolute value of the drive current I is relatively small in the first period and relatively large in the second period.

  In the example shown in FIGS. 9A and 9B, the absolute value of the driving current I in the first period and the absolute value of the driving current I in the second period are constant within each period. However, it is not limited to this. For example, when the absolute value of the drive current I in the first period and the absolute value of the drive current I in the second period change in each period, the control unit 40 determines the drive current I in each period. The discharge lamp driving unit 230 may be controlled such that the average absolute value is relatively small in the first period and relatively large in the second period. Further, for example, when the absolute value of the drive current I in the first period and the absolute value of the drive current I in the second period change within the respective periods, the control unit 40 determines the drive current I in the first period. The discharge lamp driving unit 230 may be controlled to take the minimum absolute value and take the maximum absolute value of the driving current I in the second period.

  In the projector 500 according to the first embodiment, in the first control, the control unit 40 controls the discharge lamp driving unit 230 so that an alternating current is supplied to the discharge lamp 90 as the driving current I in the first period. The alternating current is a current that alternately repeats the first polarity and the second polarity. In the example shown in FIG. 9A, the discharge lamp driving unit 230 reverses the polarity while maintaining the absolute value of the current value of the driving current I within the first period, thereby generating an alternating current corresponding to one cycle. The control unit 40 controls the discharge lamp driving unit 230 so that it is generated and supplied to the discharge lamp 90 as the driving current I. In the example shown in FIG. 9A, an alternating current for four cycles is supplied to the discharge lamp 90 as a driving current I in one first period. The frequency of the alternating current can be determined experimentally according to the characteristics of the discharge lamp 90. For example, the frequency of the alternating current may be selected in the range of 30 Hz to 1 kHz.

  In the projector 500 according to the first embodiment, in the first control, the control unit 40 causes the energy given to the first electrode 92 during the second period to be applied to the second electrode 93 during the second period in the second period. A first control process is performed to control the discharge lamp driving unit 230 so as to supply the discharge lamp 90 with a driving current I that is greater than the applied energy.

  In the example shown in FIG. 9A, in the first control process, the control unit 40 causes the discharge lamp driving unit 230 to supply the discharge lamp 90 with a direct current having the first electrode serving as an anode as the driving current I. Is controlling. The direct current with the first electrode serving as an anode is a current that starts with the first polarity and is composed of a current of the first polarity. In the example shown in FIG. 9A, the discharge lamp driving unit 230 supplies a direct current with a constant absolute value of the drive current I within the second period to the discharge lamp 90 as the drive current I. In addition, the control unit 40 controls the discharge lamp driving unit 230. Thereby, a 1st control process is realizable by simple control.

  In the projector 500 according to the first embodiment, in the second control, the control unit 40 controls the discharge lamp driving unit 230 so that an alternating current is supplied to the discharge lamp 90 as the driving current I in the first period. In the example shown in FIG. 9B, the discharge lamp driving unit 230 inverts the polarity while maintaining the absolute value of the current value of the driving current I within the first period, thereby generating an alternating current corresponding to one cycle. The control unit 40 controls the discharge lamp driving unit 230 so that it is generated and supplied to the discharge lamp 90 as the driving current I. In the example shown in FIG. 9B, an alternating current for four cycles is supplied to the discharge lamp 90 as a driving current I in one first period. The frequency of the alternating current can be determined experimentally according to the characteristics of the discharge lamp 90. For example, the frequency of the alternating current may be selected in the range of 30 Hz to 1 kHz.

  In the projector 500 according to the first embodiment, in the second period, the control unit 40 causes the energy given to the second electrode 93 during the second period to be greater than the energy given to the first electrode 92 during the second period. A second control process for controlling the discharge lamp driving unit 230 so as to supply the discharge lamp 90 with an increasing driving current I is performed.

  In the example shown in FIG. 9B, in the second control process, the control unit 40 causes the discharge lamp 90 to supply a direct current with the second electrode serving as an anode to the discharge lamp 90 as the drive current I. Is controlling. The direct current with the second electrode serving as an anode is a current that starts with the second polarity and is composed of a second polarity current. In the example shown in FIG. 9B, the discharge lamp driving unit 230 supplies a direct current with a constant absolute value of the drive current I within the second period to the discharge lamp 90 as the drive current I. In addition, the control unit 40 controls the discharge lamp driving unit 230. Thereby, a 2nd control process is realizable by simple control.

  According to the projector 500 according to the first embodiment, since the energy given to the first electrode 92 is increased in the first control process, the meltability of the first electrode 92 is increased. Therefore, deformation of the first electrode 92 can be suppressed. Further, according to the projector 500 according to the first embodiment, the energy given to the second electrode is increased in the second control process, so that the meltability of the second electrode 93 is increased. Therefore, deformation of the second electrode 93 can be suppressed. Therefore, deformation of the first electrode 92 and the second electrode 93 can be suppressed by performing the first control process and the second control process.

  Further, according to the projector 500 according to the first embodiment, the control unit 40 controls the discharge lamp driving unit 230 so that the absolute value of the driving current I is minimum in the first period and maximum in the second period. Therefore, when driving with the average driving power throughout the first period and the second period being constant, the driving is performed with the average driving power in the second period, which is darker than the driving with the average driving power in the first period. The image can be projected brighter than if In the first period, there is a period in which both the right shutter 412 and the left shutter 414 are closed. Therefore, even if the projected image is dark, the image quality is hardly affected. On the other hand, in the second period, either the right shutter 412 or the left shutter 414 is in an open state, and the image projected to the user can appear brighter than when driving with average driving power. . Therefore, it is possible to realize a projector that can project an image so that it looks bright. Further, the occurrence of crosstalk can be suppressed by projecting the image darkly in the first period. In addition, since it is possible to suppress the need to increase the average driving power in order to make the video appear brighter, the power consumption of the projector can be suppressed. As a result, it is possible to suppress the deterioration of the peripheral components accompanying the increase in the average driving power.

  In the projector 500 according to the first embodiment, the control unit 40 may perform the second control in a period that is at least a part of a period sandwiched between temporally adjacent first control periods.

  In the example shown in FIG. 8, the first control period from time t11 to time t15 and the first control period from time t19 to time t23 are temporally adjacent. A period from time t15 to time t19 that is a period between these two first control periods is a second control period. That is, in the example shown in FIG. 8, the entire period between the first control periods that are temporally adjacent is the second control period. Therefore, in the example shown in FIG. 8, the first control period and the second control period are alternately repeated.

By performing the second control in a period that is at least a part of the period between the first control periods that are temporally adjacent, the thermal load balance between the first electrode 92 and the second electrode 93 of the discharge lamp 90 is maintained. be able to. Therefore, it can suppress that the electrode of a discharge lamp wears out unevenly.

1-6. Modification 1
FIG. 10A is a timing chart showing another waveform example in the first control, and FIG. 10B is a timing chart showing another waveform example in the second control. 10A and 10B, the horizontal axis represents time, and the vertical axis represents the current value of the drive current I. 10A and 10B, the drive current I when the first electrode 92 is an anode is a positive value, and the drive current I when the second electrode 93 is an anode is a negative value. Represent.

  The waveform example shown in FIGS. 9A and 9B differs from the waveform example shown in FIGS. 10A and 10B in the second period. That is, the first embodiment and the first modification are different in the contents of the first control process and the second control process, and the other configurations are the same. Therefore, only the contents of the first control process and the second control process will be described below.

  In the example shown in FIG. 10A, in the first control process (the first control in the second period), the control unit 40 takes the time during which the first electrode 92 occupying one cycle as the drive current I becomes the anode. The discharge lamp driving unit 230 is controlled so as to supply the discharge lamp 90 with an alternating current longer than the time during which the second electrode 93 becomes the anode. In the example shown in FIG. 10A, the discharge lamp driving unit 230 inverts the polarity while maintaining the absolute value of the current value of the driving current I within the second period, thereby generating an alternating current corresponding to one cycle. The control unit 40 controls the discharge lamp driving unit 230 so that it is generated and supplied to the discharge lamp 90 as the driving current I. In addition, the control unit 40 controls the discharge lamp driving unit 230 so that the polarity of the driving current I is reversed at a timing such that the duration of the first polarity lasts longer than the duration of the second polarity. Yes. Thereby, a 1st control process is realizable by simple control.

  In the example shown in FIG. 10B, in the second control process (second control in the second period), the control unit 40 uses the second electrode 93 that occupies one cycle as the anode as the drive current I. The discharge lamp driving unit 230 is controlled so that an alternating current that is longer than the time during which the first electrode 92 becomes the anode is supplied to the discharge lamp 90. In the example shown in FIG. 10B, the discharge lamp driving unit 230 inverts the polarity while keeping the absolute value of the current value of the driving current I constant within the second period, thereby generating an alternating current corresponding to one cycle. The control unit 40 controls the discharge lamp driving unit 230 so that it is generated and supplied to the discharge lamp 90 as the driving current I. In addition, the control unit 40 controls the discharge lamp driving unit 230 so as to reverse the polarity of the driving current I at a timing such that the duration of the second polarity lasts longer than the duration of the first polarity. Yes. Thereby, a 2nd control process is realizable by simple control.

  According to the first modification, the energy given to the first electrode 92 is increased in the first control process, so that the meltability of the first electrode 92 is increased. Therefore, deformation of the first electrode 92 can be suppressed. Further, according to the first modification, in the second control process, the energy given to the second electrode is increased, so that the meltability of the second electrode 93 is increased. Therefore, deformation of the second electrode 93 can be suppressed. Therefore, deformation of the first electrode 92 and the second electrode 93 can be suppressed by performing the first control process and the second control process.

1-7. Modification 2
FIG. 11A is a timing chart showing another waveform example in the first control, and FIG. 11B is a timing chart showing another waveform example in the second control. 11A and 11B, the horizontal axis represents time, and the vertical axis represents the current value of the drive current I. In FIGS. 11A and 11B, the drive current I when the first electrode 92 is an anode is a positive value, and the drive current I when the second electrode 93 is an anode is a negative value. Represent.

  The waveform example shown in FIGS. 9A and 9B and the waveform example shown in FIGS. 11A and 11B differ in the waveform in the second period. That is, in the first embodiment and the second modification, the contents of the first control process and the second control process are different, and the other configurations are the same. Therefore, only the contents of the first control process and the second control process will be described below.

  In the example shown in FIG. 11A, in the first control process (first control in the second period), the control unit 40 has a period in which an alternating current is supplied as the drive current I, and the first electrode 92 is an anode. The discharge lamp driving unit 230 is controlled to include a period during which the direct current to be supplied to the discharge lamp 90 is included. In the example shown in FIG. 11A, in a period in which an alternating current is supplied, the discharge lamp driving unit 230 reverses the polarity while keeping the absolute value of the current value of the driving current I within the second period. Thus, the control unit 40 controls the discharge lamp driving unit 230 so that an alternating current corresponding to one cycle is generated and supplied to the discharge lamp 90 as the driving current I. In the example shown in FIG. 11A, in the period in which the direct current is supplied, the discharge lamp driving unit 230 generates a direct current in which the absolute value of the current value of the drive current I is constant within the second period. The control unit 40 controls the discharge lamp driving unit 230 so that the driving current I is supplied to the discharge lamp 90. Thereby, a 1st control process is realizable by simple control.

  In the example shown in FIG. 11B, in the second control process (first control in the second period), the control unit 40 has a period in which an alternating current is supplied as the drive current I, and the second electrode 93 is an anode. The discharge lamp driving unit 230 is controlled to include a period during which the direct current to be supplied to the discharge lamp 90 is included. In the example shown in FIG. 11B, in the period in which the alternating current is supplied, the discharge lamp driving unit 230 reverses the polarity while keeping the absolute value of the current value of the driving current I within the second period. Thus, the control unit 40 controls the discharge lamp driving unit 230 so that an alternating current corresponding to one cycle is generated and supplied to the discharge lamp 90 as the driving current I. In the example shown in FIG. 11B, in the period in which the direct current is supplied, the discharge lamp driving unit 230 generates a direct current in which the absolute value of the current value of the drive current I is constant within the second period. The control unit 40 controls the discharge lamp driving unit 230 so that the driving current I is supplied to the discharge lamp 90. Thereby, a 2nd control process is realizable by simple control.

  In the example shown in FIGS. 11A and 11B, control is performed such that an alternating current is supplied at the beginning of the second period and a direct current is supplied at the end of the second period. The order of the current and the direct current is arbitrary.

  According to the second modification, the energy given to the first electrode 92 is increased in the first control process, so that the meltability of the first electrode 92 is increased. Therefore, deformation of the first electrode 92 can be suppressed. Moreover, according to the modification 2, since the energy given to a 2nd electrode becomes large in a 2nd control process, the meltability of the 2nd electrode 93 increases. Therefore, deformation of the second electrode 93 can be suppressed. Therefore, deformation of the first electrode 92 and the second electrode 93 can be suppressed by performing the first control process and the second control process.

2. Projector According to Second Embodiment Next, a projector 500 according to a second embodiment will be described. The configuration of the optical system, circuit, and the like of the projector 500 according to the second embodiment is the same as that of the projector 500 according to the first embodiment. Therefore, a specific example of control of the drive current I in the projector 500 according to the second embodiment will be described below. Note that the temporal relationship between the contents of the drive signals 572R, 572G, and 572B, the open / close state of the right shutter 412, the open / close state of the left shutter 414, the first period and the second period, and the switching timing has already been described with reference to FIG. That's right.

FIG. 12 is a diagram for explaining the relationship between the switching timing and the first control period, the second control period, and the third control period. The horizontal axis of FIG. 12 represents time. Times t11 to t27 are switching timings. The first control period is a period during which the control unit 40 performs the first control, the second control period is a period during which the control unit 40 performs the second control, and the third control period is the period during which the control unit 40 performs the third control. This is the period during which control is performed. The contents of the first control and the second control are the same as those in the first embodiment, and thus detailed description thereof is omitted.

  In the projector 500 according to the second embodiment, the control unit 40 continues for at least a third control period that is different from the first control period and the second control period during the period between the switching timings adjacent in time. I do. In the example shown in FIG. 12, the first control, the second control, and the third control are continued for a period twice as long as the period between the temporally adjacent switching timings. For example, in FIG. 12, the first first control period continues during a period from time t13 as the switching timing to time t15 as the switching timing. In FIG. 12, the first second control period continues from the time t17 as the switching timing to the time t19 as the switching timing. Further, in FIG. 12, the first third control period continues during a period from time t11 as the switching timing to time t13 as the switching timing. The length of time for which the first control, the second control, and the third control are continued can be appropriately set according to the specification of the discharge lamp 90.

  FIG. 13 is a timing chart showing a waveform example in the third control. In FIG. 13, the horizontal axis represents time, and the vertical axis represents the current value of the drive current I. In FIG. 13, the driving current I when the first electrode 92 is an anode is represented as a positive value, and the driving current I when the second electrode 93 is an anode is represented as a negative value.

  In the projector 500 according to the second embodiment, in the third control, the control unit 40 causes the absolute value of the drive current I to be relatively smaller in the first period than in the second period, and the first value in the second period. The discharge lamp driving unit 230 is controlled so as to be relatively larger than the period.

  In the example shown in FIG. 13, the absolute value of the current value of the drive current I is I1 in the first period and I2 in the second period. In the example shown in FIG. 13, I1 <I2. Therefore, in the third control, the absolute value of the drive current I is relatively small in the first period and relatively large in the second period.

  In the example shown in FIG. 13, the absolute value of the drive current I in the first period and the absolute value of the drive current I in the second period are constant in each period, but are not limited thereto. For example, when the absolute value of the drive current I in the first period and the absolute value of the drive current I in the second period change in each period, the control unit 40 determines the drive current I in each period. The discharge lamp driving unit 230 may be controlled such that the average absolute value is relatively small in the first period and relatively large in the second period. Further, for example, when the absolute value of the drive current I in the first period and the absolute value of the drive current I in the second period change within the respective periods, the control unit 40 determines the drive current I in the first period. The discharge lamp driving unit 230 may be controlled to take the minimum absolute value and take the maximum absolute value of the driving current I in the second period.

In the projector 500 according to the second embodiment, in the third control, the control unit 40 may control the discharge lamp driving unit 230 to supply an alternating current to the discharge lamp 90 as the driving current I in the first period. Good. In the example shown in FIG. 13, the discharge lamp driving unit 230 generates an alternating current corresponding to one cycle by inverting the polarity while keeping the absolute value of the current value of the driving current I constant within the first period. The control unit 40 controls the discharge lamp driving unit 230 so that the driving current I is supplied to the discharge lamp 90. In the example shown in FIG. 13, the alternating current for four cycles is supplied to the discharge lamp 90 as the driving current I in one first period. The frequency of the alternating current can be determined experimentally according to the characteristics of the discharge lamp 90. For example,
The frequency of the alternating current may be selected in the range of 30 Hz to 1 kHz.

  In the projector 500 according to the second embodiment, in the third control, the control unit 40 controls the discharge lamp driving unit 230 to supply a direct current as the driving current I to the discharge lamp 90 in the first period. May be. In this case, for example, in two first periods sandwiching one second period in time, the discharge lamp driving unit 230 is controlled to supply the discharge lamp 90 with direct currents having opposite polarities as the driving current I. May be. Thereby, the heat load balance of the electrode of a discharge lamp can be maintained. Therefore, it can suppress that the electrode of a discharge lamp wears out unevenly.

  In the projector 500 according to the second embodiment, in the third control, the control unit 40 determines that the difference between the energy given to the first electrode 92 and the energy given to the second electrode 93 during the second period is the first control. And the discharge lamp drive part 230 is controlled so that the drive current I smaller than the case of 2nd control is supplied to the discharge lamp 90. FIG. That is, the difference between the energy given to the first electrode 92 during the second period in the third control and the energy given to the second electrode 93 is the energy given to the first electrode 92 during the second period in the first control. And the energy given to the second electrode 93 is smaller than the difference between the energy given to the first electrode 92 and the energy given to the second electrode 93 during the second period in the second control.

  In the example shown in FIG. 13, in the projector 500 according to the second embodiment, in the third control, the control unit 40 releases the alternating current as the driving current I to the discharge lamp 90 in the second period. The lamp driving unit 230 is controlled. In the example shown in FIG. 13, the discharge lamp driving unit 230 generates an alternating current corresponding to one cycle by inverting the polarity while keeping the absolute value of the current value of the driving current I constant within the second period. The control unit 40 controls the discharge lamp driving unit 230 so that the driving current I is supplied to the discharge lamp 90. In the example illustrated in FIG. 13, the control unit is configured to invert the polarity of the drive current I at a timing such that the duration of the first polarity and the duration of the second polarity are the same length. Reference numeral 40 controls the discharge lamp driving unit 230. In the example shown in FIG. 13, alternating current for two cycles is supplied to the discharge lamp 90 as the drive current I in one second period.

  In the projector 500 according to the second embodiment, the control unit 40 is driven at a timing such that the duration of the first polarity and the duration of the second polarity are different in the second period of the third control. The discharge lamp driving unit 230 may be controlled so as to reverse the polarity of the current I. In that case, the control unit is configured to invert the polarity of the drive current I so that the difference is smaller than the difference between the duration of the first polarity and the duration of the second polarity in the first control and the second control. 40 may control the discharge lamp driving unit 230.

  As described above, in the third control, the driving current I that keeps the thermal load balance of the electrodes of the discharge lamp 90 as a whole (the bias of the thermal load balance is small) is released as compared with the first control and the second control. The discharge lamp driving unit 230 is controlled so as to be supplied to the electric lamp 90.

  In the projector 500 according to the second embodiment, the control unit 40 may perform at least one of the first control and the second control in a period between the third control periods that are temporally adjacent.

In the example shown in FIG. 12, the third control period from time t11 to time t13 and the third control period from time t15 to time t17 are temporally adjacent. A period from time t13 to time t15, which is a period between these two third control periods, is a first control period. In the example shown in FIG. 12, the third control period from time t15 to time t17 and the third control period from time t19 to time t21 are temporally adjacent. A period from time t17 to time t19 that is a period between these two third control periods is a second control period.

  As described above, the control unit 40 performs at least one of the first control and the second control in the period between the third control periods that are temporally adjacent to each other, thereby melting the electrodes by the first control and the second control. It is possible to suppress adverse effects such as blackening caused by excessively high performance.

  Also, as shown in FIG. 12, in the second embodiment as well, in the same way as in the first embodiment, the first control is performed in the first control period, and the period between the first control periods that are temporally adjacent to each other is The second control is performed in the second control period that is at least a part. Thereby, the thermal load balance between the first electrode 92 and the second electrode 93 of the discharge lamp 90 can be maintained. Therefore, it can suppress that the electrode of a discharge lamp wears out unevenly.

3. Projector according to Third Embodiment Next, a projector 500 according to a third embodiment will be described. The configuration of the optical system, circuit, and the like of the projector 500 according to the third embodiment is the same as that of the projector 500 according to the first embodiment. Therefore, a specific example of control of the drive current I in the projector 500 according to the third embodiment will be described below. The contents of the first control, the second control, and the third control are the same as those in the first embodiment and the second embodiment, and thus detailed description thereof is omitted.

  The projector 500 according to the third embodiment includes a state detection unit (voltage detection unit 60) that detects the deterioration state of the discharge lamp 90, and the control unit 40 increases the length of the third control period as the deterioration state progresses. Shorten the length.

  The state detection unit, for example, as a value representing the degree of the deterioration state, for example, the drive voltage Vla of the discharge lamp 90, the time change of the drive voltage Vla of the discharge lamp 90, the light quantity of the discharge lamp 90, the time change of the light quantity of the discharge lamp 90, The accumulated lighting time of the discharge lamp 90 may be detected. In the third embodiment, the voltage detection unit 60 (state detection unit) detects the drive voltage Vla of the discharge lamp 90 as the deterioration state of the discharge lamp 90.

  FIG. 14 is a flowchart illustrating a control example of the projector according to the third embodiment. In the flowchart shown in FIG. 14, control from when the discharge lamp 90 is stably lit to when it is turned off is shown.

  First, the voltage detector 60 detects the drive voltage Vla (step S100). Next, the control unit 40 selects a driving condition corresponding to the driving voltage Vla detected in step S100 from the correspondence relationship stored in the storage unit 44 (step S102).

  FIG. 15 is a diagram illustrating an example of a correspondence relationship between driving conditions. In the example illustrated in FIG. 15, the lengths of the first control period and the second control period are constant at a length that is three times the period between two temporally adjacent switching timings. Further, the length of the third control period is shortened as the drive voltage Vla increases (as the deterioration state of the discharge lamp 90 progresses). In the example shown in FIG. 15, the length of the third control period based on the length of the period between two temporally adjacent switching timings is three times when the drive voltage Vla is less than 80V. When the driving voltage Vla is 80 V or more and less than 95 V, the length is doubled, and when the driving voltage Vla is 95 V or more, the length is 1 time.

After selecting the drive condition in step S102 of FIG. 14, the control unit 40 determines whether or not the drive condition needs to be changed (step S104). When the control unit 40 determines that the drive condition needs to be changed (YES in step S104), the drive unit 90 is changed to the drive condition selected in step S102 and the discharge lamp 90 is driven (step S106). . When the control unit 40 determines that it is not necessary to change the driving condition (NO in step S104), the discharge lamp 90 is continuously driven under the previous driving condition.

  In the case of NO in step S104 and after step S106, the control unit 40 determines whether or not there is an instruction to turn off the discharge lamp 90 (step S108). When the control unit 40 determines that there is a turn-off command (YES in step S108), the lighting of the discharge lamp 90 is ended (turned off). When the control unit 40 determines that there is no turn-off command (NO in step S108), the control from step S100 to step S108 is repeated until there is a turn-off command.

  When the deterioration state of the first electrode 92 and the second electrode 93 of the discharge lamp 90 progresses, the distance between the first electrode 92 and the second electrode 93 (interelectrode distance) increases. As the interelectrode distance increases, the drive voltage Vla increases. That is, the drive voltage Vla increases with the progress of the deterioration state.

  Therefore, in the projector 500 of the third embodiment, the length of the third control period is shortened as the drive voltage Vla increases (progress of the deterioration state). As the deterioration state of the discharge lamp 90 proceeds, the meltability of the electrode decreases. Therefore, as the deterioration state of the discharge lamp 90 progresses, the length of the third control period is shortened to increase the frequency of the first control and the second control, thereby increasing the meltability of the electrodes and suppressing the deformation of the electrodes. . In addition, when the deterioration state of the discharge lamp 90 is not progressing, it is possible to suppress adverse effects such as blackening caused by the excessively high meltability of the electrode by not increasing the meltability of the electrode more than necessary.

4). Projector According to Fourth Embodiment Next, a projector 500 according to a fourth embodiment will be described. The configuration of the optical system, the circuit, and the like of the projector 500 according to the fourth embodiment is the same as that of the projector 500 according to the first embodiment. Therefore, a specific example of control of the drive current I in the projector 500 according to the fourth embodiment will be described below. The contents of the first control, the second control, and the third control are the same as those in the first embodiment and the second embodiment, and thus detailed description thereof is omitted.

  The projector 500 according to the fourth embodiment includes a state detection unit (voltage detection unit 60) that detects a deterioration state of the discharge lamp 90, and the control unit 40 includes the first control period and the first control period as the deterioration state progresses. 2 Increase the length of the control period.

  The state detection unit, for example, as a value representing the degree of the deterioration state, for example, the drive voltage Vla of the discharge lamp 90, the time change of the drive voltage Vla of the discharge lamp 90, the light quantity of the discharge lamp 90, the time change of the light quantity of the discharge lamp 90, The accumulated lighting time of the discharge lamp 90 may be detected. In the fourth embodiment, the voltage detection unit 60 (state detection unit) detects the drive voltage Vla of the discharge lamp 90 as the deterioration state of the discharge lamp 90.

  The control flow in the fourth embodiment is the same as the control flow in the third embodiment described with reference to FIG. 14, and only the correspondence relationship of the drive conditions selected in step S102 is different.

FIG. 16 is a diagram illustrating an example of a correspondence relationship between driving conditions. In the example shown in FIG. 16, the length of the third control period is constant at a length that is three times the period between two temporally adjacent switching timings. Further, the lengths of the first control period and the second control period become longer as the drive voltage Vla becomes larger (as the deterioration state of the discharge lamp 90 progresses). In the example shown in FIG. 16, the length of the first control period and the second control period based on the length of the period between two temporally adjacent switching timings is when the drive voltage Vla is less than 80V. Is twice as long when the driving voltage Vla is 80V or more and less than 95V, and is three times when the driving voltage Vla is 95V or more.

  When the deterioration state of the first electrode 92 and the second electrode 93 of the discharge lamp 90 progresses, the distance between the first electrode 92 and the second electrode 93 (interelectrode distance) increases. As the interelectrode distance increases, the drive voltage Vla increases. That is, the drive voltage Vla increases with the progress of the deterioration state.

  Therefore, in the projector 500 of the fourth embodiment, the lengths of the first control period and the second control period are increased as the drive voltage Vla increases (progress of the deterioration state). As the deterioration state of the discharge lamp 90 proceeds, the meltability of the electrode decreases. Therefore, by increasing the lengths of the first control period and the second control period as the deterioration state of the discharge lamp 90 progresses, it is possible to improve the meltability of the electrode and suppress the deformation of the electrode. In addition, when the deterioration state of the discharge lamp 90 is not progressing, it is possible to suppress adverse effects such as blackening caused by the excessively high meltability of the electrode by not increasing the meltability of the electrode more than necessary.

  In the third embodiment, an example in which the length of the third control period is shortened as the deterioration state of the discharge lamp 90 progresses. In the fourth embodiment, as the deterioration state of the discharge lamp 90 progresses, Although the example which lengthens the length of 1 control period and 2nd control period was demonstrated, it is also possible to combine these.

  In each of the embodiments described above, the projector 500 is configured to cause the viewer to stereoscopically display the first video and the second video as the left-eye video and the right-eye video, respectively, but is not limited thereto. For example, the projector may adopt a configuration in which the first video and the second video are videos having different contents, and two display videos (first video and second video) are visually recognized by different viewers.

  When configured in this manner, the active shutter glasses are provided with left and right shutters that operate in the same manner as the right shutter 412 described above, and left and right shutters that operate in the same manner as the left shutter 414 described above. Two types of glasses may be provided.

  In each of the above embodiments, a projector using three liquid crystal panels has been described as an example. However, the present invention is not limited to this, and one, two, four or more liquid crystal panels are used. It can also be applied to projectors.

  In each of the above embodiments, a transmissive projector has been described as an example. However, the present invention is not limited to this, and can be applied to a reflective projector. Here, “transmission type” means that an electro-optic modulation device as a light modulation means such as a transmission type liquid crystal panel transmits light, and “reflection type” means This means that an electro-optic modulator as a light modulator such as a reflective liquid crystal panel or a micromirror type light modulator is a type that reflects light. As the micromirror light modulator, for example, DMD (digital micromirror device; trademark of Texas Instruments) can be used. Even when the present invention is applied to a reflective projector, the same effect as that of a transmissive projector can be obtained.

  The present invention can be applied to a front projection type projector that projects from the side that observes the projected image, or to a rear projection type projector that projects from the side opposite to the side that observes the projected image. is there.

  In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention.

  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.

DESCRIPTION OF SYMBOLS 10 Discharge lamp lighting device, 20 Power control circuit, 21 Switch element, 22 Diode, 23 Coil, 24 Capacitor, 30 Polarity inversion circuit, 31 1st switch element, 32 2nd switch element, 33 3rd switch element, 34 Fourth switch element, 40 control unit, 41 system controller, 42 power control circuit controller, 43
Polarity inversion circuit controller, 44 storage unit, 50 sub-reflecting mirror, 60 voltage detection unit, 61 first resistor, 62 second resistor, 63 third resistor, 70 igniter circuit, 80
DC power supply device, 90 discharge lamp, 90e1 first end, 90e2 second end, 91 discharge space, 92 first electrode, 93 second electrode, 112 main reflector, 114 fixing member, 200
Light source device, 210 light source unit, 230 discharge lamp driving unit, 305 collimating lens, 310 illumination optical system, 320 color separation optical system, 330R, 330G, 330B liquid crystal light valve, 340 cross dichroic prism, 350 projection optical system, 400 projector System, 410 Active shutter glasses, 412 Right shutter, 414 Left shutter, 500 Projector, 502 Image signal, 510 Image signal converter, 512R, 512G, 512B Image signal, 514 Sync signal, 522 Fixing member, 534 Conductive member, 536 First terminal, 544 Conductive member, 546 Second terminal, 552p protrusion, 560R, 560G, 560B Liquid crystal panel, 562p protrusion, 570 Image processing device, 572R, 572G, 572B Drive signal, 582 Communication signal No. 584 Communication signal 600 AC power supply 700 screen

Claims (18)

A projector system comprising: a projector that switches between a first video and a second video and outputs alternately at a given switching timing; and shutter glasses having a first shutter and a second shutter,
The projector is
A discharge lamp comprising a first electrode and a second electrode;
A discharge lamp driving unit that supplies a driving current for driving the discharge lamp to the discharge lamp;
A control unit for controlling the discharge lamp driving unit;
With
The period between the switching timings adjacent in time includes a first period and a second period adjacent in time after the first period,
The control unit controls the discharge lamp driving unit so that the discharge lamp is lit in the first period and the second period,
The control unit controls the discharge lamp driving unit so that an absolute value of the driving current in the second period is larger than an absolute value of the driving current in the first period;
The controller is
In the second period, the discharge lamp driving unit is controlled such that the driving current is supplied to the discharge lamp such that energy applied to the first electrode is larger than energy applied to the second electrode. Control process,
In the second period different from the second period in which the first control process is executed, the driving current in which the energy given to the second electrode is larger than the energy given to the first electrode is changed to the discharge lamp. Performing a second control process for controlling the discharge lamp drive unit to be supplied to
The first shutter and the second shutter are switched between an open state and a closed state based on a signal from the control unit,
In the first period, the first shutter and the second shutter are in the closed state,
In the second period, one of the first shutter and the second shutter is in the open state, and the other shutter is in the closed state. The projector system according to claim 1,
The said control part is a projector system which performs a said 2nd control process in at least one part of the period pinched | interposed into the period when the said 1st control process adjacent in time is performed. The projector system according to any one of claims 1 and 2,
The controller is
Energy given to the first electrode and the second electrode are given to the second electrode in a second period different from the second period in which the first control process is executed and the second period in which the second control process is executed. Performing a third control that controls the discharge lamp driving unit so that the drive current is supplied to the discharge lamp with a difference in energy that is smaller than the difference between the first control process and the second control process;
A projector system that performs at least one of the first control process and the second control process in a period sandwiched between periods in which the third control is temporally adjacent. The projector system according to claim 3,
The projector includes a state detection unit that detects a deterioration state of the discharge lamp,
The said control part is a projector system which shortens the length of the period when said 3rd control is performed with progress of the said deterioration state. The projector system according to claim 3,
The projector includes a state detection unit that detects a deterioration state of the discharge lamp,
The control unit increases the length of a period during which the first control process is executed and a period during which the second control process is executed as the deterioration state progresses. The projector system according to any one of claims 1 to 5,
The controller is
In the first control process, as the drive current, the discharge lamp drive unit is controlled so that a direct current with the first electrode serving as an anode is supplied to the discharge lamp,
In the second control process, a projector system that controls the discharge lamp driving unit so as to supply a direct current with the second electrode serving as an anode to the discharge lamp as the driving current. The projector system according to any one of claims 1 to 5,
The controller is
In the first control process, as the drive current, an alternating current that is longer than a time during which the first electrode occupies one cycle in a cycle is longer than a time during which the second electrode becomes an anode is supplied to the discharge lamp. Controlling the discharge lamp driving unit;
In the second control process, as the drive current, an AC current that is longer than a time during which the second electrode occupies one cycle in the period is longer than a time during which the first electrode becomes an anode is supplied to the discharge lamp. A projector system for controlling the discharge lamp driving unit. The projector system according to any one of claims 1 to 5,
The controller is
In the first control process, the driving current including a period in which an alternating current is supplied and a period in which a direct current in which the first electrode serves as an anode is supplied to the discharge lamp is supplied to the discharge lamp. Controlling the discharge lamp drive,
In the second control process, the driving current including a period in which an alternating current is supplied and a period in which a direct current in which the second electrode serves as an anode is supplied to the discharge lamp is supplied to the discharge lamp. Projector system that controls the discharge lamp drive. The projector system according to any one of claims 1 to 8,
The said control part is a projector system which controls the said discharge lamp drive part so that the average drive power through the said 1st period and the said 2nd period may become fixed. A projector that switches between a first video and a second video at a given switching timing and alternately outputs them,
A discharge lamp comprising a first electrode and a second electrode;
A discharge lamp driving unit that supplies a driving current for driving the discharge lamp to the discharge lamp;
A control unit for controlling the discharge lamp driving unit;
Including
The period between the switching timings adjacent in time includes a first period and a second period adjacent in time after the first period,
The control unit controls the discharge lamp driving unit so that the discharge lamp is lit in the first period and the second period,
The control unit controls the discharge lamp driving unit so that an absolute value of the driving current in the second period is larger than an absolute value of the driving current in the first period;
The controller is
In the second period, the discharge lamp driving unit is controlled such that the driving current is supplied to the discharge lamp such that energy applied to the first electrode is larger than energy applied to the second electrode. Control process,
In the second period different from the second period in which the first control process is executed, the driving current in which the energy given to the second electrode is larger than the energy given to the first electrode is changed to the discharge lamp. A projector that performs a second control process for controlling the discharge lamp driving unit so as to be supplied to the projector. The projector according to claim 10.
The said control part is a projector which performs a said 2nd control process in at least one part of the period pinched | interposed into the period when the said 1st control process adjacent in time is performed. The projector according to any one of claims 10 and 11,
The controller is
Energy given to the first electrode and the second electrode are given to the second electrode in a second period different from the second period in which the first control process is executed and the second period in which the second control process is executed. Performing a third control that controls the discharge lamp driving unit so that the drive current is supplied to the discharge lamp with a difference in energy that is smaller than the difference between the first control process and the second control process;
A projector that performs at least one of the first control process and the second control process in a period sandwiched between periods in which the third control is temporally adjacent. The projector according to claim 12, wherein
Including a state detection unit for detecting a deterioration state of the discharge lamp,
The said control part is a projector which shortens the length of the period when said 3rd control is performed with progress of the said deterioration state. The projector according to claim 12, wherein
Including a state detection unit for detecting a deterioration state of the discharge lamp,
The control unit increases a length of a period during which the first control process is executed and a period during which the second control process is executed as the deterioration state progresses. The projector according to any one of claims 10 to 14,
The controller is
In the first control process, as the drive current, the discharge lamp drive unit is controlled so that a direct current with the first electrode serving as an anode is supplied to the discharge lamp,
In the second control process, the projector controls the discharge lamp driving unit so that the driving current is supplied to the discharge lamp with a direct current in which the second electrode serves as an anode. The projector according to any one of claims 10 to 14,
The controller is
In the first control process, as the drive current, an alternating current that is longer than a time during which the first electrode occupies one cycle in a cycle is longer than a time during which the second electrode becomes an anode is supplied to the discharge lamp. Controlling the discharge lamp driving unit;
In the second control process, as the drive current, an AC current that is longer than a time during which the second electrode occupies one cycle in the period is longer than a time during which the first electrode becomes an anode is supplied to the discharge lamp. A projector for controlling the discharge lamp driving unit. The projector according to any one of claims 10 to 14,
The controller is
In the first control process, the driving current including a period in which an alternating current is supplied and a period in which a direct current in which the first electrode serves as an anode is supplied to the discharge lamp is supplied to the discharge lamp. Controlling the discharge lamp drive,
In the second control process, the driving current including a period in which an alternating current is supplied and a period in which a direct current in which the second electrode serves as an anode is supplied to the discharge lamp is supplied to the discharge lamp. A projector that controls the discharge lamp drive. The projector according to any one of claims 10 to 17,
The said control part is a projector which controls the said discharge lamp drive part so that the average drive power through the said 1st period and the said 2nd period may become fixed.

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