JP2018045805A - Discharge lamp driving device, light source device, projector, and discharge lamp driving method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a discharge lamp driving device capable of improving a life of a discharge lamp.SOLUTION: A discharge lamp driving device comprises a drive section, a detection section and a control section. The drive section has a plurality of drive patterns having driving currents being supplied to a discharge lamp and different from one another. The control section sequentially selects one drive pattern out of the plurality of drive patterns at predetermined timing in accordance with a predetermined selectivity in a lighting period of the discharge lamp, and controls the drive section such that the driving current corresponding to the drive pattern selected is supplied to the discharge lamp. When an amount of change between a first voltage between electrodes before previous lighting-off and a second voltage between electrodes after this time lighting-on of the discharge lamp is greater than a predetermined value, the control section makes a selectivity of a first drive pattern having longest drive time in a predetermined period until the previous lighting-off of the discharge lamp smaller than a selectivity of the first drive pattern in a previous lighting period.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a discharge lamp driving device, a light source device, a projector, and a discharge lamp driving method.

  As a light source device of a projector, a discharge lamp such as a high pressure mercury lamp or a metal halide lamp may be used. The following Patent Document 1 discloses a high-pressure discharge lamp including a discharge lamp lighting circuit, a starting circuit, a lamp voltage detection circuit, an abnormality determination unit, an abnormality processing unit, and an elapsed time detection circuit after the discharge lamp is extinguished. A projector including an electric lamp lighting device is disclosed. In this projector, the abnormality determination unit determines that the discharge lamp is abnormal when the lamp voltage is equal to or lower than the reference voltage.

JP 2007-59281 A

  In the projector described above, the abnormality determination unit determines the state of the discharge lamp based only on the lamp voltage, that is, the voltage between the electrodes. Therefore, the state of the discharge lamp cannot be accurately grasped, and the life of the discharge lamp may be reduced.

  Specifically, according to the projector described above, the interelectrode distance can be detected based on the interelectrode voltage, but the thickness of the protrusion at the tip of the electrode of the discharge lamp cannot be detected. Therefore, even if the lamp voltage is within a predetermined voltage range and the discharge lamp is determined to be normal, if the protrusion at the tip of the electrode is thin, the protrusion may disappear and the discharge lamp may deteriorate rapidly. It was.

  One aspect of the present invention has been made to solve the above-described problems, and an object of the present invention is to provide a discharge lamp driving device that can improve the life of the discharge lamp. Another object of one aspect of the present invention is to provide a light source device including such a discharge lamp driving device. Another object of one embodiment of the present invention is to provide a projector including such a light source device. Another object of one aspect of the present invention is to provide a discharge lamp driving method capable of improving the life of a discharge lamp.

  In order to achieve the above object, a discharge lamp driving device according to one aspect of the present invention detects a voltage between electrodes of a driving unit that supplies a driving current to a discharge lamp having a pair of electrodes, and the discharge lamp. A detection unit; and a control unit that controls the drive unit. The driving unit has a plurality of driving patterns having different driving currents supplied to the discharge lamp. The control unit sequentially selects one of the plurality of drive patterns at a predetermined timing according to a predetermined selection rate during a lighting period of the discharge lamp, and a drive current corresponding to the selected drive pattern Is controlled to be supplied to the discharge lamp. The control unit has a predetermined amount of change between the first interelectrode voltage detected before the discharge lamp is turned off and the second interelectrode voltage detected after the discharge lamp is turned on this time. Is greater than the selection rate of the first drive pattern in the previous lighting period, the selection rate of the first drive pattern having the longest drive time in the predetermined period until the previous turn-off of the discharge lamp.

  If the protrusion at the tip of the electrode of the discharge lamp is thin, the protrusion disappears due to an impact at the start of discharge of the discharge lamp, thereby increasing the distance between the electrodes and increasing the voltage between the electrodes. In the discharge lamp driving device according to one aspect of the present invention, the change is detected in order to detect the amount of change between the first interelectrode voltage before the previous extinction of the discharge lamp and the second interelectrode voltage after the current lighting. When the amount is larger than a predetermined value, it can be estimated that the protrusion was thin before the current discharge lamp was turned on. Therefore, the control unit makes the selection rate of the first drive pattern that has the longest driving time in the predetermined period until the discharge lamp is turned off earlier than the selection rate of the first drive pattern in the previous lighting period. Thereby, in the lighting period after this time, the driving time by the first drive pattern is shorter than that in the previous lighting period, and the thinning of the protrusion is suppressed. Thus, according to the discharge lamp driving device of one aspect of the present invention, the shape of the protrusion at the tip of the electrode can be maintained well, so that the life of the discharge lamp can be improved.

  In the discharge lamp driving device according to one aspect of the present invention, the control unit has a second drive having a higher selectivity than the reduced selectivity of the first drive pattern when the amount of change is greater than the predetermined value. A pattern may be selected.

  According to this configuration, the second drive pattern having a higher selectivity than the lowered selectivity of the first drive pattern, in other words, the first drive pattern determined to be preferable to the first drive pattern for maintaining the protrusion shape. The discharge lamp is driven by two driving patterns. Thereby, since the shape of the protrusion at the tip of the electrode can be maintained, the life of the discharge lamp can be improved.

  In the discharge lamp driving device according to one aspect of the present invention, when the change amount is larger than the predetermined value, the control unit calculates the selection rate of the first drive pattern as an average of the selection rates of the plurality of drive patterns. It may be smaller than the value.

  According to this configuration, the probability that the first drive pattern is selected from among a plurality of drive patterns is sufficiently reduced, and the shape of the protrusion at the tip of the electrode can be maintained, so that the life of the discharge lamp can be improved.

  In the discharge lamp driving device according to one aspect of the present invention, the control unit maintains the driving pattern set when the voltage between the second electrodes is detected when the amount of change is equal to or less than a predetermined value. Also good.

  When the amount of change between the first inter-electrode voltage and the second inter-electrode voltage is smaller than a predetermined value, the drive pattern set at the time when the second inter-electrode voltage is detected causes the shape of the protrusion to deteriorate in particular. It can be estimated that it will not be. According to said structure, since the drive pattern set when the voltage between 2nd electrodes was detected is maintained, the shape of protrusion can be maintained favorable and the lifetime of a discharge lamp can be improved.

  In the discharge lamp driving device according to one aspect of the present invention, the control unit selects one of the plurality of driving patterns in the lighting period, and corresponds to the selected one driving pattern. An operation of supplying a driving current to the discharge lamp for a predetermined time and obtaining a change amount of the interelectrode voltage based on the interelectrode voltage detected at the predetermined time is repeated between the plurality of driving patterns, Correlation data between one drive pattern and the amount of change corresponding to the one drive pattern may be acquired.

  According to this configuration, the control unit refers to the correlation data between one drive pattern and the amount of change corresponding to one drive pattern, thereby determining the selection rate of each drive pattern that matches the current electrode state. It can be set appropriately.

  In the discharge lamp driving device according to one aspect of the present invention, the control unit detects the driving current corresponding to the selected one driving pattern in the lighting period in the supply period in which the driving current is supplied to the discharge lamp. The selection rate of the selected one driving pattern may be updated based on the voltage between the electrodes.

  According to this configuration, the control unit can appropriately set the selection rates of the plurality of drive patterns when detecting the interelectrode voltage.

  A light source device according to one aspect of the present invention includes the discharge lamp that emits light and the discharge lamp driving device according to one aspect of the present invention.

  Since the light source device according to one aspect of the present invention includes the discharge lamp driving device according to one aspect of the present invention, a highly reliable light source device can be realized.

  A projector according to one aspect of the present invention includes a light source device according to one aspect of the present invention, a light modulation element that modulates light emitted from the light source apparatus in accordance with a video signal, and the light modulation element that modulates the light. A projection optical system for projecting light.

  Since the projector according to one aspect of the present invention includes the light source device according to one aspect of the present invention, a highly reliable projector can be realized.

  A discharge lamp driving method according to one aspect of the present invention is a discharge lamp driving method for driving a discharge lamp by supplying a driving current to a discharge lamp having a pair of electrodes, the driving current being supplied to the discharge lamp. Have a plurality of different drive patterns, and sequentially select one drive pattern of the plurality of drive patterns at a predetermined timing according to a predetermined selection rate during the lighting period of the discharge lamp, and the selected drive A driving current corresponding to a pattern is supplied to the discharge lamp, a first interelectrode voltage detected before the discharge lamp is turned off last time, and a second interelectrode voltage detected after the discharge lamp is turned on this time. When the change amount between and is larger than a predetermined value, the selection rate of the first driving pattern that has the longest driving time in the predetermined period until the previous extinction of the discharge lamp is set to the first driving in the previous lighting period. Smaller than the turn of the selection rate.

  As with the discharge lamp driving device of one aspect of the present invention, according to the discharge lamp driving method of one aspect of the present invention, the shape of the protrusion at the tip of the electrode can be maintained satisfactorily, thereby improving the life of the discharge lamp. Can do.

It is a schematic block diagram of the projector of one Embodiment. It is sectional drawing of the discharge lamp in one Embodiment. It is a block diagram which shows the various components of a projector. It is a circuit diagram of the discharge lamp lighting device of one embodiment. It is a block diagram which shows one structural example of the control part of one Embodiment. It is a figure which shows the mode of the protrusion of the electrode tip of a discharge lamp. It is a figure which shows the mode of the protrusion of the electrode tip of a discharge lamp. It is a figure which shows an example of a drive pattern. It is a flowchart which shows an example of the acquisition procedure of the correlation data between each drive pattern and the variation | change_quantity of a lamp voltage. It is a flowchart which shows an example of the process sequence of a discharge lamp drive method.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
In the following drawings, in order to make each component easy to see, the scale of the size may be varied depending on the component.

[projector]
FIG. 1 is a schematic configuration diagram of an optical system of a projector according to the present embodiment.
As shown in FIG. 1, the projector 500 of the present embodiment includes a light source device 200, a collimating lens 305, an illumination optical system 310, a color separation optical system 320, and three liquid crystal light valves (light modulation elements) 330R. , 330G, 330B, a cross dichroic prism 340, and a projection optical system 350 are provided.

  Light emitted from the light source device 200 passes through the collimating lens 305 and enters the illumination optical system 310. The collimating lens 305 collimates the light from the light source device 200.

  The illumination optical system 310 adjusts the illuminance of light emitted from the light source device 200 to be uniform on the liquid crystal light valves 330R, 330G, and 330B. Furthermore, the illumination optical system 310 aligns the polarization direction of the light emitted from the light source device 200 in one direction. The reason is that the light emitted 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 light (R), green light (G), and blue light (B). The three color lights are respectively modulated according to the video signal by the liquid crystal light valves 330R, 330G, and 330B associated with the respective color lights. The liquid crystal light valves 330R, 330G, and 330B include liquid crystal panels 560R, 560G, and 560B, which will be described later, and polarizing plates (not shown). The polarizing plates are disposed on the light incident side and the light emitting side of the liquid crystal panels 560R, 560G, and 560B, respectively.

  The three modulated 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 the screen 700 (see FIG. 3). As a result, an image is displayed on the screen 700. As each configuration 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, a well-known configuration can be adopted.

FIG. 2 is a cross-sectional view showing the configuration of the light source device 200.
As shown in FIG. 2, the light source device 200 includes a light source unit 210 and a discharge lamp lighting device (discharge lamp driving device) 10. The light source unit 210 includes a main reflecting mirror 112, a discharge lamp 90, and a sub reflecting mirror 50.

  The discharge lamp lighting device 10 supplies the drive current I 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 of the discharge lamp 90.

  The shape of the discharge lamp 90 is a rod shape extending along the irradiation direction D. One end of the discharge lamp 90 is a first end 90e1, and the other end of the discharge lamp 90 is a second end 90e2. The material of the discharge lamp 90 is a translucent material such as quartz glass, for example. The central portion of the discharge lamp 90 swells in a spherical shape, and the inside of the central portion is a discharge space 91. The discharge space 91 is filled with a gas that is a discharge medium containing a rare gas, a metal halide, or the like.

  In the discharge space 91, the tips of the first electrode (electrode) 92 and the second electrode (electrode) 93 protrude. The first electrode 92 is disposed on the first end portion 90 e 1 side of the discharge space 91. 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 of the first electrode 92 and the second electrode 93 are arranged to face each other with a predetermined distance. As the material of the first electrode 92 and the second electrode 93, a metal such as tungsten is used.

  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 penetrates the inside of the discharge lamp 90. Similarly, a second terminal 546 is provided at the second end 90e2 of the discharge lamp 90. The second terminal 546 and the second electrode 93 are electrically connected by a conductive member 544 that penetrates the inside of the discharge lamp 90. As a material of the first terminal 536 and the second terminal 546, a metal such as tungsten is used. As a material of the conductive members 534 and 544, molybdenum foil or the like 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 driving current I 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 90e1 of the discharge lamp 90 by a fixing member 114. The main reflecting mirror 112 reflects the light traveling toward the opposite side of the irradiation direction D in the discharge light toward the irradiation direction D. The shape of the reflecting surface (the surface on the discharge lamp 90 side) of the main reflecting mirror 112 is not particularly limited as long as the discharge light can be reflected in the irradiation direction D. For example, even if it is a spheroidal shape, it is a rotating parabola. It may be a shape. For example, when the shape of the reflecting surface of the main reflecting mirror 112 is a parabolic shape, the main reflecting mirror 112 can convert the discharge light into light substantially parallel to the optical axis AX. Thereby, 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 portion of the discharge space 91 on the second end 90e2 side. The sub-reflecting mirror 50 reflects the light traveling toward the side opposite to the side on which the main reflecting mirror 112 is disposed in 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.

  The material of the fixing members 114 and 522 is not particularly limited as long as it is a heat resistant material that can withstand the heat generated from the discharge lamp 90, and for example, an inorganic adhesive is used. 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 an arbitrary method is adopted. be able to. For example, the discharge lamp 90 and the main reflecting mirror 112 may be independently fixed to a housing (not shown) of the projector 500. The same applies to the sub-reflecting mirror 50.

Hereinafter, the circuit configuration of the projector 500 will be described.
FIG. 3 is a diagram illustrating an example of a circuit configuration of the projector 500 according to the present embodiment.
In addition to the optical system shown in FIG. 1, the projector 500 includes an image signal conversion unit 510, a DC power supply device 80, liquid crystal panels 560R, 560G, and 560B, an image processing device 570, and a CPU (Central Processing Unit) 580. It is equipped with.

  The image signal conversion unit 510 converts an image signal 502 (such as a luminance-color difference signal or an analog RGB signal) input from the outside 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.

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

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

  The discharge lamp lighting device 10 generates a high voltage between the electrodes of the discharge lamp 90 at the time of start-up and causes dielectric breakdown to form a discharge path. After forming the discharge path, the discharge lamp lighting device 10 supplies a driving current I for maintaining the discharge of the discharge lamp 90.

  Liquid crystal panels 560R, 560G, and 560B are provided in the liquid crystal light valves 330R, 330G, and 330B, respectively. The liquid crystal panels 560R, 560G, and 560B modulate the transmittance (luminance) of color light incident on the liquid crystal panels 560R, 560G, and 560B via the optical system described above based on the drive signals 572R, 572G, and 572B, respectively. .

  The CPU 580 controls various operations from the start of lighting of the projector 500 to the turning off of the projector 500. For example, in the example of FIG. 3, a lighting command or a lighting command is output to the discharge lamp lighting device 10 via the communication signal 582. The CPU 580 receives lighting information of the discharge lamp 90 from the discharge lamp lighting device 10 via the communication signal 584.

[Discharge lamp lighting device]
Hereinafter, the configuration of the discharge lamp lighting device 10 will be described.
FIG. 4 is a diagram illustrating an example of a circuit configuration of the discharge lamp lighting device 10.
As shown in FIG. 4, the discharge lamp lighting device 10 includes a power control circuit 20, a polarity inversion circuit 30, a control unit 40, an operation detection unit 60, and an igniter circuit 70.

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

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

  When the switching element 21 is turned on, a current flows through the coil 23 and energy is stored in the coil 23. Thereafter, when the switching 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 switching element 21 is turned on is generated.

  The polarity inversion circuit 30 inverts the polarity of the direct current Id input from the power control circuit 20 at a predetermined timing. As a result, the polarity inversion circuit 30 generates a drive current I that is a direct current that continues for a controlled time, or a drive current I that is an alternating current having an arbitrary frequency, and outputs these currents. In the present embodiment, the polarity inverting circuit 30 is configured by an inverter bridge circuit (full bridge circuit).

  The polarity inversion circuit 30 includes a first switching element 31, a second switching element 32, a third switching element 33, and a fourth switching element 34 configured by transistors and the like. The polarity inverting circuit 30 has a configuration in which a first switching element 31 and a second switching element 32 connected in series and a third switching element 33 and a fourth switching 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 switching element 31, the second switching element 32, the third switching element 33, and the fourth switching element 34, respectively. Based on the polarity inversion control signal, ON / OFF operations of the first switching element 31, the second switching element 32, the third switching element 33, and the fourth switching element 34 are controlled.

  In the polarity inverting circuit 30, the operation of alternately turning on / off the first switching element 31 and the fourth switching element 34 and the second switching element 32 and the third switching element 33 is repeated. Thereby, the polarity of the direct current Id output from the power control circuit 20 is alternately inverted. The polarity inversion circuit 30 is in the same polarity state for a controlled time from the common connection point of the first switching element 31 and the second switching element 32 and the common connection point of the third switching element 33 and the fourth switching element 34. Is generated, or a drive current I which is an alternating current having a controlled frequency is generated, and these currents are output.

  That is, in the polarity inversion circuit 30, the second switching element 32 and the third switching element 33 are OFF when the first switching element 31 and the fourth switching element 34 are ON, and the first switching element 31 and the fourth switching element 34 are OFF. When is OFF, the second switching element 32 and the third switching element 33 are controlled to be ON. Therefore, when the first switching element 31 and the fourth switching element 34 are ON, a driving current I that flows from the one end of the capacitor 24 in the order of the first switching element 31, the discharge lamp 90, and the fourth switching element 34 is generated. When the second switching element 32 and the third switching element 33 are ON, a driving current I that flows from the one end of the capacitor 24 through the third switching element 33, the discharge lamp 90, and the second switching element 32 is generated.

  In the present embodiment, the combined portion of the power control circuit 20 and the polarity inversion circuit 30 corresponds to the discharge lamp driving unit 230. The discharge lamp driving unit 230 supplies a driving current I for driving the discharge lamp 90 to the discharge lamp 90.

  The control unit 40 controls the discharge lamp driving unit 230. In the example of FIG. 4, the control unit 40 controls the power control circuit 20 and the polarity inversion circuit 30, thereby maintaining the drive current I with the same polarity, the current value of the drive current I (the power value of the drive power). ), Control parameters such as frequency. The control unit 40 performs polarity reversal control for the polarity reversing circuit 30 to control the holding time during which the drive current I continues at the same polarity, the frequency of the drive current I, and the like according to the polarity reversal timing of the drive current I. The control unit 40 performs current control for controlling the current value of the output direct current Id on the power control circuit 20.

  The configuration of the control unit 40 is not particularly limited. In the present 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 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 inversion circuit 30 by controlling the power control circuit controller 42 and the polarity inversion circuit controller 43. The system controller 41 may control the power control circuit controller 42 and the polarity inversion circuit controller 43 based on the lamp voltage Vla (interelectrode voltage) and the drive current I detected by the operation detection unit 60.

  In the present embodiment, a storage unit 44 is connected to the system controller 41. The system controller 41 controls the power control circuit 20 and the polarity inversion circuit 30 based on the information stored in the storage unit 44. The storage unit 44 stores 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 duty ratio, a waveform, and a modulation pattern.

  In the present embodiment, the storage unit 44 stores a plurality of drive patterns in which combinations of drive parameters such as the above-described frequency, the length of an AC period described later, and the length of a DC period described later are different from each other. . Further, the storage unit 44 stores correlation data between individual drive patterns and a change amount of a lamp voltage Vla described later.

  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.

  The control unit 40 is realized using a dedicated circuit, and can perform the above-described control and various types of control of processing to be described later. On the other hand, for example, the control unit 40 can function as a computer when the CPU executes a control program stored in the storage unit 44, and can 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. On the other hand, the CPU 580 may be configured to bear a part of the function of the control unit 40.

  In the present embodiment, the operation detection unit 60 includes a voltage detection unit 60 </ b> A that detects the lamp voltage Vla of the discharge lamp 90 and outputs lamp voltage information to the control unit 40. Furthermore, the operation detection unit 60 includes a current detection unit 60B that detects the drive current I and outputs drive current information to the control unit 40. In the present embodiment, the operation detection unit 60 includes a first resistor 61, a second resistor 62, and a third resistor 63.

  The voltage detection unit 60A of the operation detection unit 60 includes a first resistor 61 and a second resistor 62 that are connected in parallel to the discharge lamp 90 and connected in series to each other. The voltage detection unit 60A detects the lamp voltage Vla based on the voltage divided by the first resistor 61 and the second resistor 62. The current detection unit 60B includes a third resistor 63 connected in series with the discharge lamp 90. The current detection unit 60 </ b> B detects the drive current I based on the voltage generated at both ends of the third resistor 63.

  The igniter circuit 70 operates only when the discharge lamp 90 starts to be lit. The igniter circuit 70 breaks down a space between a pair of electrodes (between the first electrode 92 and the second electrode 93) at the start of lighting of the discharge lamp 90, and generates a high voltage (discharge) necessary for forming a discharge path. (A voltage higher than that during normal lighting of the electric lamp 90) is supplied between the pair of electrodes (between the first electrode 92 and the second electrode 93). In the present embodiment, the igniter circuit 70 is connected in parallel with the discharge lamp 90.

6A and 6B are diagrams showing the tip portions of the first electrode 92 and the second electrode 93. FIG.
As shown in FIGS. 6A and 6B, a protrusion 531p is formed at the tip of the first electrode 92, and a protrusion 541p is formed at the tip of the second electrode 93. The discharge generated between the first electrode 92 and the second electrode 93 mainly occurs between the protrusion 531p and the protrusion 541p. As in the present embodiment, when the protrusions 531p and 541p are formed, the discharge positions (arc positions) of the first electrode 92 and the second electrode 93 are smaller than when the protrusions are not formed. Movement can be suppressed.

  FIG. 6A shows a first polarity state in which the first electrode 92 operates as an anode and the second electrode 93 operates as a cathode. In the first polarity state, electrons move from the second electrode 93 (cathode) to the first electrode 92 (anode) by discharge. That is, 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 531p) of the anode (first electrode 92) rises.

  FIG. 6B shows a second polarity state in which the first electrode 92 operates as a cathode and the second electrode 93 operates as an anode. In the second polarity state, electrons move from the first electrode 92 to the second electrode 93, contrary to the first polarity state. As a result, the temperature of the tip (projection 541p) of the second electrode 93 increases.

  As described above, when the driving current I is supplied to the discharge lamp 90, the temperature of the anode where the electrons collide increases. On the other hand, for the cathode that emits electrons, the temperature of the cathode decreases while the electrons are emitted toward the anode.

  The interelectrode distance L between the protrusion 531p of the first electrode 92 and the protrusion 541p of the second electrode 93 increases with the deterioration of the protrusions 531p and 541p. This is because the protrusions 531p and 541p are consumed. As the interelectrode distance L increases, the resistance between the first electrode 92 and the second electrode 93 increases, and the lamp voltage Vla increases. Therefore, a change in the interelectrode distance L can be detected by referring to the lamp voltage Vla.

  Since the first electrode 92 and the second electrode 93 have the same configuration, in the following description, the first electrode 92 may be described as a representative. Further, since the protrusion 531p at the tip of the first electrode 92 and the protrusion 541p at the tip of the second electrode 93 have the same configuration, in the following description, the protrusion 531p may be described as a representative.

Next, a driving pattern of the driving current I supplied to the discharge lamp 90 will be described.
FIG. 7 is a diagram illustrating an example of a drive pattern.
The vertical axis in FIG. 7 indicates the current value I, and the horizontal axis indicates time T. In FIG. 7, the drive current I is shown as positive when it is in the first polarity state and negative when it is in the second polarity state.

  The drive pattern shown in FIG. 7 alternately has a plurality of first mixing periods PH31 that are temporally continuous and a plurality of second mixing periods PH32 that are temporally continuous.

  The first mixing period PH31 has a first AC period PH31a, a second AC period PH31b, and a DC period PH31c in this order. The first AC period PH31a and the second AC period PH31b are periods in which an AC current in which the value of the drive current I is alternately switched between Im1 and −Im1 is supplied to the discharge lamp. The direct current period PH31c is a period in which a direct current in which the value of the drive current I is kept constant at Im1 is supplied to the discharge lamp.

  The second mixing period PH32 has a first AC period PH32a, a second AC period PH32b, and a DC period PH32c in this order. Similar to the first mixing period PH31, the first AC period PH32a and the second AC period PH32b are periods in which an AC current in which the value of the drive current I is alternately switched between Im1 and -Im1 is supplied to the discharge lamp. . The direct current period PH31c is a period in which a direct current that is maintained constant at a value of the drive current I at -Im1 is supplied to the discharge lamp. That is, the polarity of the drive current I in the direct current period PH32c of the second mixed period PH32 is inverted with respect to the drive current I in the direct current period PH31c of the first mixed period PH31.

  As an example of specific driving parameters, the frequency of the alternating current in the first alternating periods PH31a and PH32a is 200 Hz. The lengths t31a and t32a of the first AC periods PH31a and PH32a are the length of three cycles of the 200 Hz AC current, that is, 15 ms (milliseconds). The frequency of the alternating current in the second alternating periods PH31b and PH32b is 250 Hz. The lengths t31b and t32b of the second AC periods PH31b and PH32b are the length of two cycles of the AC current of 250 Hz, that is, 8 ms (milliseconds). The lengths t31c and t32c of the direct current periods PH31c and PH32c are 5 ms (milliseconds).

  Although only one type of driving pattern is shown here, in the present embodiment, the discharge lamp driving unit 230 has a combination of three types of driving parameters: frequency, AC period length, and DC period length. The discharge lamp 90 is driven by a drive current I having n different drive patterns.

  In the present embodiment, the lighting period is defined as a period from when the discharge lamp 90 is turned on when the power of the projector 500 is turned on until the discharge lamp 90 is turned on until the discharge lamp 90 is turned off.

[Driving lamp driving method]
Next, a method for driving the discharge lamp 90 of this embodiment will be described.
FIG. 8 is a flowchart illustrating an example of a procedure for acquiring correlation data between each drive pattern and the amount of change in the lamp voltage Vla.
FIG. 9 is a flowchart illustrating an example of a processing procedure of the discharge lamp driving method.

  In the light source device 200 of the present embodiment, the control unit 40 selects one drive pattern from the n drive patterns, and appropriately switches the selected drive pattern. The discharge lamp driving unit 230 supplies a driving current I corresponding to the selected driving pattern to the discharge lamp 90. More specifically, in the lighting period of the discharge lamp 90, the control unit 40 sequentially selects one of a plurality (n) of driving patterns at a predetermined timing according to a predetermined selection rate. The discharge lamp driving unit 230 is controlled so that the drive current I corresponding to the drive pattern is supplied to the discharge lamp 90. In the present embodiment, when switching the drive pattern to be selected, the control unit 40 sequentially selects any one drive pattern from the drive patterns other than the currently selected drive pattern at random.

  However, the control unit 40 does not necessarily select one drive pattern at random, and the selection order may be set in advance. In this case, the selection rates of the drive patterns are set to be the same, for example. Further, the predetermined timing is, for example, a time when each drive pattern is executed, and is set to a predetermined time, for example. The predetermined timing may be the same between the drive patterns or may be set differently.

  In the shipping stage of the projector 500, when the driving current I corresponding to each driving pattern is supplied to the discharge lamp 90, n driving patterns predicted to some extent with respect to the change in the lamp voltage Vla are stored in the storage unit 44. However, depending on how the user uses the projector 500, the usage environment, the accumulated usage time, etc., the lamp voltage Vla may not change as expected. Therefore, at the initial lighting stage of the light source device 200, the light source device 200 acquires initial correlation data between each drive pattern and the amount of change in the lamp voltage Vla.

Hereinafter, a procedure for acquiring initial correlation data between each drive pattern and the amount of change in the lamp voltage Vla will be described with reference to FIG.
First, when the power of the projector 500 is turned on, lighting of the discharge lamp 90 is started in the light source device 200 (step S1).
Here, the control unit 40 selects one of the n drive patterns (a plurality of drive patterns) during the lighting period of the discharge lamp 90 (step S2). The discharge lamp drive unit 230 supplies the drive current I corresponding to the selected drive pattern to the discharge lamp 90 (step S3).

  Next, the operation detection unit 60 detects the lamp voltage Vlas in the initial stage in the supply period in which the selected drive current I is supplied to the discharge lamp 90 (step S4). The control unit 40 stores the detected lamp voltage Vlas in the storage unit 44.

  Next, the control unit 40 determines whether or not a predetermined time has elapsed since the drive current I corresponding to the drive pattern selected in Step S2 is supplied to the discharge lamp 90 (Step S5). In the present embodiment, the predetermined time is appropriately set within a range of 15 minutes to 2 hours, for example, but is not particularly limited to this range. As described above, the predetermined time as the predetermined timing may be a fixed time or may be set differently between the drive patterns. If the predetermined time has not elapsed (step S5: NO), the supply of the drive current I corresponding to the selected drive pattern is continued.

  When the predetermined time has elapsed (step S5: YES), the operation detection unit 60 detects the lamp voltage Vlaf after the supply period of the selected drive current I reaches the predetermined time (step S6). The control unit 40 stores the detected lamp voltage Vlaf in the storage unit 44.

  Next, the control unit 40 determines the lamp voltage Vlas at the initial stage in the supply period in which the drive current I corresponding to the selected drive pattern is supplied to the discharge lamp 90, and a predetermined time after the drive current I is supplied. The change amount of the lamp voltage Vlaf after the lapse is calculated and acquired (step S7). The control unit 40 stores the acquired change amount of the lamp voltage Vla in the storage unit 44. That is, correlation data between the drive pattern and the amount of change in the lamp voltage Vla is acquired for one selected drive pattern. In the present embodiment, the change amount of the lamp voltage Vla includes a voltage value as a difference and a sign indicating increase / decrease. That is, the amount of change in the lamp voltage Vla is acquired as + 5V, -2V, for example.

  Next, the control unit 40 determines whether or not acquisition of correlation data between the drive pattern and the amount of change in the lamp voltage Vla has been completed for all n drive patterns (step S8).

  When acquisition of correlation data has not been completed for all n driving patterns (step S8: NO), the control unit 40 proceeds to step S2 and selects one driving pattern (not selected in the previous step S2) ( A drive pattern for which initial correlation data has not yet been acquired is selected, and the process proceeds to the subsequent steps. During the lighting period of the discharge lamp 90, the control unit 40 sequentially selects one of the plurality of drive patterns at a predetermined timing according to a predetermined selection rate, and the drive current I corresponding to the selected drive pattern. The discharge lamp driving unit 230 is controlled so that is supplied to the discharge lamp 90. The predetermined selection rate in the procedure for obtaining the initial correlation data between each drive pattern and the amount of change in the lamp voltage Vla shown in FIG. 9 is set to a selection rate at which all n drive patterns are selected in step 2. Has been. The predetermined timing is a predetermined time set for each drive pattern as described above.

  That is, the control unit 40 selects one of the plurality of drive patterns, supplies the drive current I corresponding to the selected drive pattern to the discharge lamp 90 for a predetermined time, and detects the lamp detected at the predetermined time. The operation of obtaining the change amount of the lamp voltage Vla based on the voltage Vla is repeated between a plurality of drive patterns, and correlation data between one drive pattern and the change amount of the lamp voltage Vla corresponding to one drive pattern is obtained. To do.

  When the above procedure is repeated and the acquisition of initial correlation data for all n drive patterns is completed, the control unit 40 performs a process of acquiring initial correlation data between each drive pattern and the amount of change in the lamp voltage Vla. The process ends (step S9).

Next, a driving method of the discharge lamp 90 after obtaining initial correlation data between each driving pattern and the lamp voltage change amount will be described with reference to FIG.
After acquiring the initial correlation data, the control unit 40 selects and selects one drive pattern from the n drive patterns according to the selection rate based on the initial correlation data set for each drive pattern. The drive pattern is switched every predetermined period (for example, 15 minutes to 2 hours).

  Here, a drive that selects one drive pattern from a plurality of drive patterns at a predetermined timing according to a selection rate based on the initial correlation data, and supplies a drive current I corresponding to the selected drive pattern to the discharge lamp 90. As described above, the amount of change in the lamp voltage Vla in each drive pattern may differ from the initial correlation data acquired at the beginning of lighting of the light source device 200, depending on the accumulated usage time of the projector 500, as described above. . In this case, if the drive pattern is switched between the plurality of drive patterns based on the initial correlation data as described above, the lamp voltage Vla is lowered or increased with respect to a desired range. The discharge lamp 90 may be deteriorated. Therefore, as illustrated in FIG. 9, the control unit 40 performs control to update the change amount of the lamp voltage Vla in each drive pattern, that is, the correlation data.

  First, when the power source of the light source device 200 is turned on, lighting of the discharge lamp 90 is started (step S11).

Next, the operation detection unit 60 detects the second lamp voltage Vla2 after the discharge lamp 90 is turned on (step S12). When the second lamp voltage Vla2 is detected, the first lamp voltage Vla1 detected by the operation detection unit 60 before the discharge lamp 90 is turned off last time is stored in the storage unit 44.
In the following description, the lamp voltage detected by the operation detection unit 60 before the discharge lamp 90 is turned off last time is referred to as a first lamp voltage Vla1, and is detected by the operation detection unit 60 after the discharge lamp 90 is turned on this time. The lamp voltage is referred to as a second lamp voltage Vla2.

  Next, the control unit 40 determines whether the amount of change between the first lamp voltage Vla1 before the discharge lamp 90 is previously turned off and the second lamp voltage Vla2 after the discharge lamp 90 is turned on is equal to or less than a predetermined value. It is determined whether or not (step S13). More specifically, the change amount is a change amount of the second lamp voltage Vla2 with respect to the first lamp voltage Vla1. In the present embodiment, the predetermined value is set to +3 V, for example. The controller 40 determines whether or not the amount of change between the first lamp voltage Vla1 and the second lamp voltage Vla2 is + 3V or less. However, the predetermined value is not limited to +3 V, and can be changed as appropriate.

  When the change amount of the second lamp voltage Vla2 with respect to the first lamp voltage Vla1 is +3 V or more (step S13: NO), the controller 40 may cause the protrusions 531p and 541p at the electrode tip of the discharge lamp 90 to disappear. Judge.

  Here, when the power source of the projector 500 is turned on while the discharge lamp 90 is turned off, the drive current I is supplied to the discharge lamp 90 in a state where the drive current I is not supplied, and the first of the discharge lamp 90 is supplied. A rapid heat load is applied to the electrode 92 and the second electrode 93. At this time, when the protrusions 531p and 541p at the tips of the electrodes 91 and 92 are thinner than the protrusions 532p and 542p shown in FIGS. 6A and 6B, for example, the protrusions are lost or disappeared due to a rapid thermal load. The interelectrode distance L suddenly increases. That is, when lighting of the discharge lamp 90 is started, if the protrusions 531p and 541p at the tips of the electrodes 91 and 92 are thin, the second lamp voltage Vla2 greatly increases with respect to the first lamp voltage Vla1. Therefore, when the change amount of the second lamp voltage Vla2 with respect to the first lamp voltage Vla1 is greater than or equal to a predetermined value in step S13, the control unit 40 has already reduced the protrusions 531p and 541p before the current lighting of the discharge lamp 90. It is determined that there may have been an abnormality.

  According to the knowledge of the present inventor, it is considered that the projection at the tip of each electrode in the discharge lamp is less likely to progress rapidly, and the projection gradually becomes thinner after a long lighting period. From this, it can be considered that the drive pattern (first drive pattern) having the longest drive time in the predetermined period until the previous discharge of the discharge lamp 90 has the most influence on the thinness of the protrusions 531p and 541p. Hereinafter, the drive pattern in which the drive time is the longest in a predetermined period until the discharge lamp 90 is previously turned off is referred to as a first drive pattern.

  Based on the above determination, the control unit 40 determines that the first drive pattern is an unfavorable drive pattern for maintaining the shapes of the protrusions 531p and 541p. Therefore, the control unit 40 makes the selection rate of the first drive pattern smaller than the selection rate of the first drive pattern in the previous lighting period of the discharge lamp 90 (step S14). That is, the control unit 40 updates correlation data between one drive pattern and the amount of change in the lamp voltage Vla. More specifically, the control unit 40 makes the selection rate of the first drive pattern smaller than, for example, the average value of the selection rates set for each drive pattern among a plurality of (n) drive patterns.

  Next, the control unit 40 selects a drive pattern (second drive pattern) having a higher selection rate than the reduced selection rate of the first drive pattern from among the plurality of drive patterns (step S15). The selected second drive pattern may be a drive pattern having a higher selection rate than the selection rate of the drive pattern selected at the time when the second lamp voltage Vla2 is detected in step S12.

  Next, the discharge lamp drive unit 230 supplies the drive current I corresponding to the selected drive pattern to the discharge lamp 90 (step S17). In this case, the discharge lamp driving unit 230 supplies the driving current I corresponding to the second driving pattern to the discharge lamp 90.

  On the other hand, when the amount of change in the second lamp voltage Vla2 with respect to the first lamp voltage Vla1 is +3 V or less (step S13: YES), the controller 40 lacks or disappears the protrusions 531p and 541p at the electrode tip of the discharge lamp 90. It is judged that no has occurred. That is, the control unit 40 does not have a shape abnormality such as narrowing of the protrusions 531p and 541p before the current lighting of the discharge lamp 90, or the shape change is within an allowable range. It is determined that there is no problem with one or more drive patterns selected during the lighting period.

  Therefore, the control unit 40 continues to select the drive pattern that was selected immediately before the discharge lamp 90 was turned off during the current lighting period of the discharge lamp 90 (step S16). In other words, the control unit 40 maintains the drive pattern that was set when the second lamp voltage Vla2 was detected by the operation detection unit 60. Next, the process proceeds to step S <b> 17, and the discharge lamp driving unit 230 supplies the driving current I corresponding to the selected driving pattern to the discharge lamp 90.

  Next, the control unit 40 determines whether or not a predetermined time has elapsed since the drive current I corresponding to the drive pattern selected in Step S15 or Step S16 was supplied to the discharge lamp 90 (Step S18). . If the predetermined time has not elapsed (step S18: NO), the supply of the drive current I corresponding to the selected drive pattern is continued.

  When the predetermined time has elapsed (step S18: YES), the operation detection unit 60 detects the third lamp voltage Vla3 after the supply period of the selected drive current I reaches the predetermined time (step S19). The control unit 40 stores the detected third lamp voltage Vla3 in the storage unit 44.

  Next, the control unit 40 determines whether or not the amount of change between the second lamp voltage Vla2 and the third lamp voltage Vla3 detected in step S12 is within a predetermined range (step S20). In the present embodiment, the predetermined range is set to ± 2 V, for example, but can be changed as appropriate. Specifically, the control unit 40 determines whether or not the amount of change between the second lamp voltage Vla2 and the third lamp voltage Vla3 is within ± 2V.

  When the amount of change between the second lamp voltage Vla2 and the third lamp voltage Vla3 is within a predetermined range (step S20: YES), the control unit 40 determines that no abnormality has occurred in the protrusions 531p and 541p. To do. That is, the control unit 40 determines that the currently selected drive pattern is a preferable drive pattern for maintaining the protrusion shape. Therefore, the control unit 40 makes the selection rate of the currently selected drive pattern larger than the selection rate of the drive pattern at the current time (step S21). That is, the control unit 40 selects the selected lamp based on the lamp voltage Vla detected in the supply period in which the driving current I corresponding to the selected driving pattern is supplied in the lighting period of the discharge lamp 90. Update the selection rate of one drive pattern. In other words, the control unit 40 updates correlation data between one drive pattern and the amount of change in the lamp voltage Vla.

  Next, the control unit 40 selects another drive pattern different from the currently selected drive pattern in accordance with the selection rate set for each drive pattern (step S22). The discharge lamp driving unit 230 supplies the driving current I corresponding to the other selected driving pattern to the discharge lamp 90 (step S25).

  On the other hand, when the amount of change is outside the predetermined range (step S20: NO), the control unit 40 determines that the shape abnormality of the protrusions 531p and 541p has occurred. That is, the control unit 40 determines that the currently selected drive pattern is an unfavorable drive pattern for maintaining the protrusion shape. Therefore, the control unit 40 makes the selection rate of the currently selected drive pattern smaller than the current drive pattern selection rate (step S23). That is, the control unit 40 selects the selected lamp based on the lamp voltage Vla detected in the supply period in which the driving current I corresponding to the selected driving pattern is supplied in the lighting period of the discharge lamp 90. Update the selection rate of one drive pattern. In other words, the control unit 40 updates correlation data between one drive pattern and the amount of change in the lamp voltage Vla. For example, the control unit 40 makes the selection rate of the currently selected drive pattern smaller than the average value of the selection rates set for each drive pattern among the plurality of drive patterns.

  Next, the control unit 40 selects a drive pattern (third drive pattern) having a higher selection rate than the reduced selection rate of the currently selected drive pattern from among the plurality of drive patterns (step S24). Next, the process proceeds to step S25, and the discharge lamp driving unit 230 supplies the driving current I corresponding to the selected third driving pattern to the discharge lamp 90.

  Thereafter, the control unit 40 repeats the procedure of steps S18 to S25.

  Next, when the light source device 200 is turned off, the discharge lamp 90 is turned off. As described above, the operation detection unit 60 detects the first lamp voltage Vla1 before the discharge lamp 90 is extinguished, and the control unit 40 stores the detected first lamp voltage Vla1 in the storage unit 44.

  In the discharge lamp lighting device 10 of the present embodiment, the control unit 40 determines whether the discharge lamp 90 is turned off when the change amount between the first lamp voltage Vla1 and the second lamp voltage Vla2 is larger than a predetermined value. The selection rate of the first drive pattern in which the drive time is the longest in the predetermined period is made smaller than the selection rate of the first drive pattern in the previous lighting period of the discharge lamp 90. Thereby, in the lighting period of the discharge lamp 90 after this time, the driving time according to the first driving pattern determined to be unfavorable for maintaining the protrusion shape is within the predetermined period until the previous discharge lamp 90 is extinguished. Is less than the driving time. As a result, it is possible to suppress the occurrence of shape abnormality such as thinning of the protrusions 531p and 541p at the tip of the electrode and stabilize the protrusion shape. Thus, according to the discharge lamp lighting device 10 of the present embodiment, the life of the discharge lamp 90 can be improved.

  Further, in the discharge lamp lighting device 10 of the present embodiment, the control unit 40 reduces the first drive pattern when the amount of change between the first lamp voltage Vla1 and the second lamp voltage Vla2 is greater than a predetermined value. A second drive pattern having a selection rate higher than the selection rate is selected. As a result, the drive current I corresponding to the second drive pattern determined to be preferable for maintaining the protrusion shape is supplied to the discharge lamp 90. As a result, the shape of the protrusions 531p and 541p at the tip of the electrode is sufficiently maintained, so that the life of the discharge lamp 90 can be further improved.

  In the discharge lamp lighting device 10 of the present embodiment, the control unit 40 sets a plurality of first drive pattern selection rates when the amount of change between the first lamp voltage Vla1 and the second lamp voltage Vla2 is greater than a predetermined value. You may make smaller than the average value of each selectivity of this drive pattern. In this case, the driving time according to the first driving pattern, which is determined to be unfavorable for maintaining the projection shape, at least for a period after the lighting of the current discharge lamp 90 is set to a predetermined period until the previous discharge lamp 90 is turned off. It can be made much shorter than the driving time inside. Thereby, since the shape of the protrusions 531p and 541p can be maintained satisfactorily, the life of the discharge lamp 90 can be improved.

  Further, in the discharge lamp lighting device 10 of the present embodiment, the control unit 40 detects the second lamp voltage Vla2 when the amount of change between the first lamp voltage Vla1 and the second lamp voltage Vla2 is equal to or less than a predetermined value. The drive pattern set at that time is maintained. Since it can be estimated that this drive pattern does not particularly cause the protrusion shape to deteriorate, the protrusion shape can be maintained and the life of the discharge lamp 90 can be improved.

  Further, in the discharge lamp lighting device 10 of the present embodiment, the control unit 40 selects one drive pattern from the plurality of drive patterns during the lighting period of the discharge lamp 90, and corresponds to the selected one drive pattern. The operation of supplying the driving current I to the discharge lamp 90 for a predetermined time and acquiring the change amount of the lamp voltage Vla based on the lamp voltage Vla detected at the predetermined time is repeated between a plurality of driving patterns, and the control unit 40 Obtains correlation data between one drive pattern and the amount of change in the lamp voltage Vla during the lighting period. Therefore, the control unit 40 can appropriately set the selection rate of each drive pattern according to the current state of the protrusions 531p and 541p at the electrode tip by referring to the correlation data.

  Since the light source device 200 of the present embodiment includes the above-described discharge lamp lighting device 10, the light source device 200 with high reliability can be realized. In addition, since the projector 500 of the present embodiment includes the light source device 200 described above, the projector 500 with high reliability can be realized.

The technical scope of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the embodiment described above, an example in which the present invention is applied to a transmissive projector has been described, but the present invention can also be applied to a reflective projector. Here, the “transmission type” means that a liquid crystal light valve including a liquid crystal panel or the like is a type that transmits light. “Reflective type” means that the liquid crystal light valve reflects light. The light modulation device is not limited to a liquid crystal panel or the like, and may be a light modulation device using a digital micromirror device, for example.

  In the above embodiment, an example of the projector 500 using the three liquid crystal panels 560R, 560G, and 560B (liquid crystal light valves 330R, 330G, and 330B) has been described. However, the present invention uses only one liquid crystal panel. The present invention can also be applied to a projector that uses four or more liquid crystal panels.

  DESCRIPTION OF SYMBOLS 10 ... Discharge lamp lighting device (discharge lamp drive device), 40 ... Control part, 60 ... Operation | movement detection part (detection part), 90 ... Discharge lamp, 200 ... Light source device, 230 ... Discharge lamp drive part (drive part), 330R , 330G, 330B ... liquid crystal light valve (light modulation element), 350 ... projection optical system, 500 ... projector.

Claims (9)

A drive unit for supplying a drive current to a discharge lamp having a pair of electrodes;
A detection unit for detecting a voltage between the electrodes of the discharge lamp;
A control unit for controlling the driving unit;
With
The drive unit has a plurality of drive patterns with different drive currents supplied to the discharge lamp,
The control unit sequentially selects one of the plurality of drive patterns at a predetermined timing according to a predetermined selection rate during a lighting period of the discharge lamp, and a drive current corresponding to the selected drive pattern Controlling the driving unit so that is supplied to the discharge lamp,
The control unit has a predetermined amount of change between the first interelectrode voltage detected before the discharge lamp is turned off and the second interelectrode voltage detected after the discharge lamp is turned on this time. Is greater than the selection rate of the first drive pattern in the previous lighting period, the selection rate of the first drive pattern that has the longest drive time in the predetermined period until the previous extinction of the discharge lamp, Discharge lamp driving device.   2. The discharge lamp according to claim 1, wherein when the amount of change is greater than the predetermined value, the control unit selects a second drive pattern having a higher selectivity than the decreased selectivity of the first drive pattern. Drive device.   3. The control unit according to claim 1, wherein when the amount of change is larger than the predetermined value, the selection rate of the first drive pattern is made smaller than an average value of the selection rates of the plurality of drive patterns. The discharge lamp driving device described in 1.   The said control part maintains the drive pattern set at the time of detecting the said 2nd electrode voltage, when the said variation | change_quantity is below a predetermined value, It is any one of Claims 1-3. The discharge lamp driving device described. In the lighting period, the control unit
One driving pattern is selected from the plurality of driving patterns, a driving current corresponding to the selected driving pattern is supplied to the discharge lamp for a predetermined time, and the inter-electrode voltage detected at the predetermined time is set. The operation of acquiring the amount of change in the inter-electrode voltage based on the plurality of drive patterns is repeated,
The discharge lamp drive device according to any one of claims 1 to 4, wherein correlation data between the one drive pattern and the amount of change corresponding to the one drive pattern is acquired.   The control unit is configured to select the selected one based on the inter-electrode voltage detected in a supply period in which a driving current corresponding to the selected driving pattern is supplied to the discharge lamp in the lighting period. The discharge lamp driving device according to any one of claims 1 to 5, wherein the selection rate of one driving pattern is updated. A discharge lamp that emits light;
The discharge lamp driving device according to any one of claims 1 to 6,
A light source device. The light source device according to claim 7;
A light modulation element that modulates light emitted from the light source device according to a video signal;
A projection optical system for projecting light modulated by the light modulation element;
Equipped with a projector. A discharge lamp driving method for supplying a driving current to a discharge lamp having a pair of electrodes and driving the discharge lamp,
The drive current supplied to the discharge lamp has a plurality of different drive patterns,
In the lighting period of the discharge lamp, one of the plurality of driving patterns is sequentially selected at a predetermined timing according to a predetermined selection rate,
Supplying a driving current corresponding to the selected driving pattern to the discharge lamp;
When the amount of change between the first interelectrode voltage detected before the discharge lamp is turned off and the second interelectrode voltage detected after the discharge lamp is turned on is greater than a predetermined value, A discharge lamp driving method, wherein a selection rate of a first drive pattern having a longest driving time in a predetermined period until the discharge lamp is turned off is smaller than a selection rate of the first drive pattern in a previous lighting period.

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