JP2015106478A - 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 that suppresses an increase in start-up time and can sufficiently extend the life of a discharge lamp, and a light source device using such a discharge lamp driving device; a projector using such a light source device; and a discharge lamp driving method of suppressing an increase in start-up time and enabling the sufficient extension of the life of a discharge lamp.SOLUTION: One aspect of a discharge lamp driving device of the present invention includes a discharge lamp driving unit that supplies a driving current for driving a discharge lamp to a discharge lamp, a storage unit that stores deterioration information on the discharge lamp, and a control unit that controls the discharge lamp driving unit. The control unit controls the discharge lamp driving unit, in a transition period from the time of the occurrence of dielectric breakdown between electrodes of the discharge lamp until the time of the transition of the discharge lamp to a steady lighting state, so as to increase the driving current at the current gradient based on the deterioration information stored in the storage unit.

Description

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

For the purpose of improving the life of the discharge lamp, there has been proposed a configuration for controlling the drive current supplied to the discharge lamp when the discharge lamp is started up (for example, Patent Document 1).
As a method for controlling the drive current at the start-up, for example, a method is known in which the drive current is initially set low and gradually increased. By controlling the drive current in this way, the energy supplied to the discharge lamp at a stage where the discharge state is unstable can be kept low. Thereby, even if it is a case where discharge arises between an electrode and a tube inner wall, damage to a tube inner wall can be suppressed.

JP 2011-23246 A

  However, the method as described above cannot cope with the deterioration of the discharge lamp and may not sufficiently improve the life of the discharge lamp. In other words, if the discharge lamp deteriorates, for example, over time, the time until the discharge state stabilizes at the time of start-up becomes longer, so the current value of the drive current becomes higher when the discharge state is unstable. was there. As a result, damage such as devitrification occurs on the inner wall of the discharge lamp, and the life of the discharge lamp may not be sufficiently improved.

  On the other hand, if the current gradient of the drive current supplied to the discharge lamp at the time of start-up is set sufficiently gradual from the initial stage so that it can cope with the deterioration of the discharge lamp, even if the discharge lamp deteriorates, It can suppress that an electric lamp is damaged. However, this method has a problem that the time required to start up the discharge lamp increases from the initial stage.

  One aspect of the present invention has been made in view of the above-described problems, and suppresses an increase in start-up time, and can sufficiently improve the life of the discharge lamp, and such a discharge lamp driving device. An object is to provide a light source device using a discharge lamp driving device. Another object is to provide a projector using such a light source device. It is another object of the present invention to provide a discharge lamp driving method capable of suppressing an increase in start-up time and sufficiently suppressing the life of the discharge lamp.

  One aspect of the discharge lamp driving device of the present invention includes a discharge lamp driving unit that supplies a driving current for driving the discharge lamp to the discharge lamp, a storage unit that stores deterioration information of the discharge lamp, and the discharge lamp driving. A control unit that controls the storage unit, wherein the control unit stores the memory in a transition period from the time when dielectric breakdown occurs between the electrodes of the discharge lamp to the time when the discharge lamp shifts to a steady lighting state. The discharge lamp driving unit is controlled to increase the driving current with a current gradient based on the deterioration information stored in the unit.

  According to one aspect of the discharge lamp driving device of the present invention, the driving current is supplied with a current gradient based on the deterioration information in the transition period. Thereby, since the current gradient of the drive current can be controlled according to the state of deterioration of the discharge lamp, damage to the discharge lamp can be suppressed while suppressing an increase in the startup time. Therefore, according to one aspect of the discharge lamp driving device of the present invention, a discharge lamp driving device that can sufficiently improve the life of the discharge lamp while suppressing an increase in start-up time can be obtained.

The control unit may control the discharge lamp driving unit so as to increase the driving current stepwise in the transition period.
According to this configuration, the control is simple because the drive current is controlled to increase stepwise.

The deterioration information includes a cumulative lighting time of the discharge lamp, and the control unit controls the discharge lamp driving unit so that the current gradient becomes gentler as the cumulative lighting time is longer in the transition period. It is good also as a structure.
According to this configuration, the deterioration state of the discharge lamp can be grasped from the accumulated lighting time.

The deterioration information includes a voltage value applied between the electrodes of the discharge lamp in the steady lighting state, and the control unit has a gentler current gradient as the voltage value is larger in the transition period. In this manner, the discharge lamp driving unit may be controlled.
According to this configuration, it is possible to grasp the deterioration state of the discharge lamp even when the gap between the electrodes has spread regardless of the actual usage time of the discharge lamp.

  One aspect of the light source device of the present invention includes a discharge lamp that emits light and the discharge lamp driving device.

  According to one aspect of the light source device of the present invention, since the discharge lamp driving device is provided, a light source device that can sufficiently improve the life of the discharge lamp while suppressing an increase in start-up time can be obtained.

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

  According to one aspect of the projector of the present invention, since the light source device is provided, a projector that can sufficiently improve the life of the discharge lamp while suppressing an increase in startup time can be obtained.

  One aspect of the discharge lamp driving method of the present invention is a discharge lamp driving method for driving a discharge lamp by supplying a driving current after the dielectric breakdown occurs between the electrodes of the discharge lamp. In the transition period until the discharge lamp transitions to a steady lighting state, the discharge lamp is controlled to increase with a gradient based on the deterioration information of the discharge lamp.

  According to one aspect of the discharge lamp driving method of the present invention, the life of the discharge lamp can be sufficiently improved while suppressing an increase in start-up time in the same manner as described above.

It is a schematic block diagram of the projector of this embodiment. It is a figure which shows the discharge lamp in this embodiment. It is a block diagram which shows the various components of the projector of this embodiment. It is a circuit diagram of the discharge lamp lighting device of this embodiment. It is a block diagram which shows the example of 1 structure of the control part of this embodiment. It is explanatory drawing for demonstrating the relationship between the polarity of the drive current supplied to a discharge lamp, and the temperature of an electrode. It is explanatory drawing for demonstrating lighting operation of the discharge lamp in the projector of this embodiment. It is a figure which shows the discharge state inside a discharge lamp. It is a flowchart which shows an example of control of the discharge lamp drive part in the transition period by the control part of this embodiment.

Hereinafter, a projector according to an embodiment of the invention will be described with reference to the drawings.
The scope of the present invention is not limited to the following embodiment, and can be arbitrarily changed within the scope of the technical idea of the present invention. Moreover, in the following drawings, in order to make each structure easy to understand, the actual structure may be different from the scale, number, or the like in each structure.

  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 has a function of collimating light from the light source device 200.

  The illumination optical system 310 has a function of adjusting the illuminance of light emitted from the light source device 200 to be uniform on the liquid crystal light valves 330R, 330G, and 330B. The illumination optical system 310 also has a function of aligning the polarization direction of 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 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, which will be described later, and polarizing plates (not shown). The polarizing plates are disposed on the light incident side and the light emission 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. Various 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 a diagram illustrating a configuration of the light source device 200. The light source device 200 includes a light source unit 210 and a discharge lamp lighting device (discharge lamp driving device) 10. FIG. 2 shows a cross-sectional view of the light source unit 210. 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 a drive current (drive 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 of the discharge lamp 90.

  The shape of the discharge lamp 90 is a rod shape extending along the irradiation direction D. One end (the left end in the figure) of the discharge lamp 90 is a first end 90e1, and the other end (the right end in the figure) 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 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 92 and the second 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 so as to 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 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. The material of the first terminal 536 and the second terminal 546 is, for example, a metal such as tungsten. As a material 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 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. Parabolic shape may be sufficient. 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 is, for example, an inorganic adhesive. 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 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.

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, a CPU (Central Processing Unit) 580, and the like. 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 supplies drive signals 572R, 572G, and 572B for driving the liquid crystal panels 560R, 560G, and 560B to the liquid crystal panels 560R, 560G, and 560B, respectively.

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

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

  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.

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, a storage unit 44, an operation detection unit 60, and an igniter circuit 70. Yes.

  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 switch element 21, a diode 22, a coil 23, and a capacitor 24. The switch element 21 is composed of, for example, a transistor. In the present embodiment, one end of the switch 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 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.

  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 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 and outputs a drive current I that is a direct current that lasts for a controlled time, or a drive current I that is an alternating current having an arbitrary frequency. 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, 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. The polarity inversion circuit 30 includes a first switch element 31 and a second switch element 32 connected in series, and a third switch element 33 and a fourth switch element 34 connected in series, which are connected in parallel to each other. It has a configuration. 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 polarity inversion control signal, ON / OFF operations of the first switch element 31, the second switch element 32, the third switch element 33, and the fourth switch element 34 are controlled.

  In the polarity inverting circuit 30, the operation of alternately turning on / off the first switch element 31 and the fourth switch element 34 and the second switch element 32 and the third switch element 33 is repeated. Thereby, the polarity of the direct current Id output from the power control circuit 20 is alternately inverted. From the common connection point of the first switch element 31 and the second switch element 32 and the common connection point of the third switch element 33 and the fourth switch element 34, the same polarity state is continued for a controlled time. A drive current I that is a direct current or a drive current I that is an alternating current having a controlled frequency is generated and output.

  That is, in the polarity inversion circuit 30, 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 OFF, and the first switch element 31 and When the fourth switch element 34 is OFF, the second switch element 32 and the third switch element 33 are controlled to be 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. When the second switch element 32 and the third switch element 33 are ON, a drive current I that flows from one end of the capacitor 24 in the order of the third switch element 33, the discharge lamp 90, and the second switch 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. 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 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 to control the holding time, the current value of the drive current I, the frequency, etc. . Details will be described later.

  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. 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. 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 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 may control the power control circuit controller 42 and the polarity inversion circuit controller 43 based on the lamp 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 waveform, and a modulation pattern.

  In addition, the storage unit 44 stores deterioration information of the discharge lamp 90 and information related to the startup sequence corresponding to the deterioration information. The deterioration information is information indicating the deterioration state of the discharge lamp 90. The deterioration information is not particularly limited as long as the deterioration state of the discharge lamp 90 can be grasped. For example, the accumulated lighting time of the discharge lamp 90 or the lamp voltage applied between the electrodes of the discharge lamp 90 in the steady lighting state. Value etc. Further, the deterioration information may be, for example, not only the instantaneous lamp voltage value but also the average value of the lamp voltage value in a predetermined time and the rate of change of the lamp voltage value per time.

  In the present specification, the “degraded state” does not mean only a state in which the performance is lowered, but means a state in which the state has changed from the initial state regardless of the improvement / degradation of the performance. In other words, the “deterioration information” includes all information indicating changes with respect to the initial state of the discharge lamp 90.

  The deterioration information is referred to by the system controller 41 when the discharge lamp 90 is started up. The system controller 41 selects a startup sequence according to the deterioration information in the storage unit 44 and controls the drive current I. The deterioration information is updated each time, for example, immediately before the discharge lamp 90 is turned off, and stored in the storage unit 44.

  The cumulative lighting time is a cumulative time for which the discharge lamp 90 is lit. Since the cumulative lighting time is information indicating the actual usage time of the discharge lamp 90, the deterioration state of the discharge lamp 90 can be grasped by using the cumulative lighting time as deterioration information.

  As the discharge lamp 90 deteriorates, the lamp voltage value in the steady lighting state tends to increase due to the deformation of the first electrode 92 and the second electrode 93. Therefore, the deterioration state of the discharge lamp 90 can be grasped by using the lamp voltage value in the steady lighting state as deterioration information. When the lamp voltage value is used as the deterioration information, for example, the deterioration state of the discharge lamp 90 can be grasped even when the gap between the electrodes has spread regardless of the actual use time of the discharge lamp. .

  The information related to the startup sequence includes information on the current gradient of the drive current I supplied between the electrodes of the discharge lamp 90 in the transition period P described later. Information regarding the startup sequence may be stored in the storage unit 44 in advance, for example, before shipment of the projector 500, or may be stored via an external device or the like after shipment.

  In the present embodiment, the current gradient does not mean only the gradient when the drive current I increases linearly, but the drive current I when the drive current I increases stepwise. It also means the rate of increase. That is, the current gradient information includes all information related to the increase in the drive current I in the transition period P. That is, for example, in the present embodiment, as will be described later, the drive current I is increased stepwise in the transition period P and the discharge lamp 90 is shifted to the steady lighting state. The gradient information is the difference in the current value of the drive current I in the preceding and succeeding stages and the time required to shift to the current value in the next stage.

  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. For example, the control unit 40 may function as a computer when the CPU executes a control program stored in the storage unit 44, and may 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.

  The operation detection unit 60 detects, for example, the lamp voltage of the discharge lamp 90, outputs the drive voltage information to the control unit 40, detects the drive current I, and outputs the drive current information to the control unit 40 A detection unit or the like may be included. In the present embodiment, the operation detection unit 60 includes a first resistor 61, a second resistor 62, and a third resistor 63.

  In the present embodiment, the voltage detection unit detects the lamp voltage by the voltage divided by the first resistor 61 and the second resistor 62 connected in series with each other in parallel with the discharge lamp 90. In the present 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 igniter circuit 70 operates only when the discharge lamp 90 starts to be lit. The igniter circuit 70 is a high voltage (discharge) necessary for forming a discharge path by dielectric breakdown between the electrodes of the discharge lamp 90 (between the first electrode 92 and the second electrode 93) at the start of lighting of the discharge lamp 90. (A voltage higher than that during normal lighting of the lamp 90) is supplied between the electrodes of the discharge lamp 90 (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.

Hereinafter, the relationship between the polarity of the drive current I and the electrode temperature will be described.
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. 6A and 6B show the operating state of the first electrode 92 and the second electrode 93. FIG. In these drawings, the tip portions of the first electrode 92 and the second electrode 93 are shown. Protrusions 552p and 562p are formed 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 mainly occurs between the protrusion 552p and the protrusion 562p. When the protrusions 552p and 562p are present as in the present embodiment, the movement of the discharge position (the position of the arc bright spot) in the first electrode 92 and the second electrode 93 can be suppressed compared to the case where there is no protrusion. .

  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 with which the electrons collide tends to be higher than the temperature of the cathode that emits electrons.

  FIG. 6C is a timing chart showing an example of the drive current I supplied to the discharge lamp 90. 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 this embodiment, as shown in FIG. 6C, for example, a rectangular wave alternating current is used as the drive current I. In the present embodiment, the drive current I is supplied to the discharge lamp 90 so that 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 driving frequency of the driving current I suitable for driving the discharge lamp 90 can be experimentally determined according to the characteristics of the discharge lamp 90. Other values Im1, -Im2, Tp, 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. Since the first polarity state P1 and the second polarity state P2 are repeated, the temperature H periodically changes between the minimum value Hmin and the maximum value Hmax. Although not shown, 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.

Next, the lighting operation of the discharge lamp 90 of the projector 500 in the present embodiment will be described.
FIG. 7A is a diagram for explaining the lighting operation of the discharge lamp 90 in the projector 500 of the present embodiment, and schematically shows the drive current I supplied from the discharge lamp driving unit 230 to the discharge lamp 90. FIG. In FIG. 7A, the vertical axis represents the current value of the drive current I, and the horizontal axis represents time T.

  FIG. 7B is a diagram for explaining the change in the discharge state between the electrodes of the discharge lamp 90, and the discharge state between the electrodes and the discharge lamp 90 are supplied together with FIG. 7A. The corresponding relationship with the drive current I is shown. In FIG. 7B, the horizontal axis indicates time T.

  In the projector 500 according to the present embodiment, as shown in FIG. 7A, the projector 500 shifts to the steady lighting state after the dielectric breakdown period Po, the transition period Pa, the transition period Pb, the transition period Pc, and the transition period Pd. . In the present embodiment, the transition period Pa to the transition period Pd are collectively referred to as the transition period P. The transition period P corresponds to a startup sequence.

The dielectric breakdown period Po is a period for applying a high voltage between the first electrode 92 and the second electrode 93 of the discharge lamp 90 to cause dielectric breakdown. In the dielectric breakdown period Po, since no discharge is generated in the discharge lamp 90, the drive current I does not flow between the electrodes of the discharge lamp 90. The dielectric breakdown period Po ends at the time TS at which dielectric breakdown occurs and transitions to the transition period P. The time TS at which dielectric breakdown occurs is a boundary point between the dielectric breakdown period Po and the transition period Pa.
When dielectric breakdown occurs between the electrodes of the discharge lamp 90, glow discharge occurs between the first electrode 92 and the second electrode 93, and the drive current I flows between the electrodes.

The transition period P is a period from the time TS at which dielectric breakdown occurs to the time TE at which the steady lighting state is shifted.
The value of the drive current I supplied in each transition period Pa, Pb, Pc, Pd is constant for each transition period, and is set to increase stepwise as the transition period changes. That is, the current value supplied to the discharge lamp 90 increases stepwise in the order of the transition period Pa, the transition period Pb, the transition period Pc, and the transition period Pd. The difference between the values of the drive currents I in adjacent periods in each transition period Pa, Pb, Pc, Pd, and the lengths t1, t2, t3, and t4 of each period are the start-up sequences stored in the storage unit 44 described above. Information, more specifically, current gradient information, which is determined according to deterioration information stored in the storage unit 44.

  In the present embodiment, the number of startup sequences that are set is not particularly limited. For example, when three start-up sequences are set and the deterioration information is set as the cumulative lighting time, an example is shown in which the cumulative lighting time is 1000 hours or more when the cumulative lighting time is less than 1000 hours. When the accumulated lighting time is 2000 hours or more, it can be set to be the third period sequence. In such a case, the current gradient is set gradually as it goes from the initial sequence to the third phase sequence. In other words, the current gradient is set to be gentler as the cumulative lighting time is longer.

  That is, for example, in the case where the accumulated lighting time of the discharge lamp 90 is stored as deterioration information in the storage unit 44, the value of the drive current I such as the transition period Pa and the transition period Pb increases as the cumulative lighting time increases. The startup sequence is set so that the length of the relatively low period becomes large. By setting in this way, even when the discharge lamp 90 is deteriorated and the time until the discharge state is stabilized becomes long, the current value of the drive current I becomes high when the discharge state is unstable. Can be suppressed.

  Further, for example, when the deterioration information is the lamp voltage value in the steady lighting state, the current gradient is set to become gentler as the lamp voltage value increases with the deterioration of the discharge lamp 90.

In the present embodiment, for example, the length t1 of the transition period Pa is determined by the relationship with the time when the discharge state inside the discharge lamp 90 changes.
As shown in FIG. 7B, the discharge state inside the discharge lamp 90 is a glow discharge state D1, a mixed state D2, and an arc discharge state after dielectric breakdown occurs and transitions from the undischarged state D0 to the discharged state. It changes in the order of D3. That is, the discharge in the discharge lamp 90 shifts from glow discharge to arc discharge as the electrodes are heated. In the transition process, a mixed state D2 in which glow discharge and arc discharge coexist in the discharge lamp 90 occurs.

FIG. 8 is a schematic diagram showing a discharge state in the discharge lamp 90 in the mixed state D2.
As shown in FIG. 8, in the mixed state D2, glow discharge GD and arc discharge AD are mixed between the first electrode 92 and the second electrode 93. In the mixed state D2, the arc discharge AD is likely to occur between the rear end portions of the first electrode 92 and the second electrode 93 that are close to the inner wall 90b of the discharge tube 90a and the inner wall 90b. When an arc discharge AD is generated between each electrode and the tube inner wall 90b, if the current value of the drive current I is large, the tube inner wall 90b becomes hot and damage to the inside of the discharge lamp 90 such as devitrification occurs. It will occur.

  Therefore, it is preferable not to increase the drive current I at least in the mixed state D2. That is, by setting the length t1 of the transition period Pa to at least the length until the discharge state in the discharge lamp 90 shifts from the glow discharge state D1 to the arc discharge state D3, The damage inside 90 can be suppressed.

  The arc discharge AD between each electrode and the tube inner wall 90b is not generated when the temperature at the tip of the electrode becomes sufficiently high. Therefore, the lengths t2, t3, and t4 of the transition periods Pb, Pc, and Pd are preferably set so that the electrode tip can be efficiently heated.

  In FIG. 7A, the drive current I in the mixed state D2 is described with a plus / minus polarity symmetry, but since the arc discharge is actually not stable, it is biased to one polarity. Often has a waveform.

Next, the control procedure of the discharge lamp driving unit 230 by the control unit 40 will be described.
FIG. 9 is a flowchart illustrating an example of control of the discharge lamp driving unit 230 during the transition period P by the control unit 40. The starting point of the flowchart in FIG. 9 is the time point TS at which dielectric breakdown occurs, that is, the starting point of the transition period P.

  First, as shown in FIG. 9, the control unit 40 determines whether or not deterioration information is stored in the storage unit 44 (step S1). In the present embodiment, a case where the cumulative lighting time of the discharge lamp 90 is used as the deterioration information will be described.

  Here, in this embodiment, if the lighting operation has been performed in the past, the cumulative lighting time of the discharge lamp 90 is stored in the storage unit 44. If the accumulated lighting time is stored in the storage unit 44 (step S1; YES), the control unit 40 sets a start-up sequence corresponding to the stored accumulated lighting time (step S2). Thereby, the current value of the drive current I in the transition period P and the lengths t1, t2, t3, and t4 of the transition periods Pa, Pb, Pc, and Pd are determined.

Here, it is assumed that the lighting operation has not been performed in the past, and the cumulative lighting time of the discharge lamp 90 is not stored in the storage unit 44 provided in the control unit 40 (step S1; NO).
If the cumulative lighting time (deterioration information) is not stored in the storage unit 44 (step S1; NO), the control unit 40 sets an initial sequence as a startup sequence of the discharge lamp 90 (step S3). The initial sequence is a sequence in which the transition periods Pa, Pb, Pc, and Pd are set so that optimum startup is possible when the discharge lamp 90 has not deteriorated.

Next, when the start-up sequence is set, the frequency and current value of the transition period Pa, which is the initial transition period in the set sequence, are set (step S4).
Next, the control unit 40 measures the operation time from the start of the current transition period (step S5), and determines whether or not this operation time has passed the specified operation time (step S6). Here, when the specified operation time has not elapsed (step S6; NO), the control unit 40 returns the processing operation to the above-described step S5, and repeatedly executes the same steps until the specified operation time has elapsed. To do. Here, the prescribed operation time is the lengths t1, t2, t3, and t4 of the transition periods Pa, Pb, Pc, and Pd.

  When the specified operation time has elapsed (step S6; YES), the control unit 40 determines whether or not the entire transition period in the set sequence has ended (step S7). Here, when all the transition periods in the set sequence have not ended (step S7; NO), the next transition period in the set sequence, here, the frequency and current value in the transition period Pb are set (step S8), returning to the above-described step S5. The steps S5 to S7 are repeated in the same manner until the entire transition period of the set sequence is completed. That is, in the example of this embodiment, steps S5 to S7 are repeated until the transition period Pd ends.

  When the entire transition period of the set sequence ends (step S7; YES), the control unit 40 sets the frequency and current value of the steady lighting state of the discharge lamp 90 as the frequency and current value of the drive current I ( Step S9).

  The control of the discharge lamp driving unit 230 by the control unit 40 can also be expressed as a discharge lamp lighting method (discharge lamp driving method). That is, according to the discharge lamp lighting method of the present embodiment, the driving current I is transferred from the time TS at which dielectric breakdown occurs between the electrodes of the discharge lamp 90 to the time period P from the time TE at which the discharge lamp 90 shifts to the steady lighting state. The control is performed so as to increase with a current gradient based on the deterioration information of the discharge lamp 90.

  According to the present embodiment, during the transition period P, the discharge lamp driving unit 230 is controlled so that the driving current I increases with a current gradient based on the deterioration information stored in the storage unit 44, so that the start-up time Thus, the life of the discharge lamp 90 can be sufficiently improved. Details will be described below.

  When the discharge lamp deteriorates, the space between the electrodes spreads, and the tip of the electrode is hardly heated. Since the discharge phenomenon inside the discharge lamp is stabilized when the electrode tip is sufficiently heated, when the discharge lamp deteriorates, the time until the discharge phenomenon becomes stable becomes longer. As a result, in a state where the discharge phenomenon inside the discharge lamp is unstable, that is, in a state where arc discharge is generated between the electrode and the inner wall of the tube, the current of the drive current I may increase. . Therefore, when the inner wall of the tube is heated, damage to the discharge lamp such as devitrification occurs, and as a result, the life of the discharge lamp may be reduced.

  On the other hand, if the current gradient of the drive current I during the transition period is set to be sufficiently gentle from the initial stage where the discharge lamp has not deteriorated, the discharge lamp may be damaged even if the discharge lamp deteriorates. Can be suppressed. However, in this case, since the transition period is set longer than necessary from the initial stage where the discharge lamp is not deteriorated, there is a problem that the startup time of the discharge lamp increases. Further, there is a risk that the discharge will be extinguished by continuing the state where the current value of the drive current I is low for a long time.

  With respect to this problem, according to the present embodiment, the control unit 40 stores the accumulated lighting time of the discharge lamp 90, the lamp voltage value in the steady lighting state, and the like in the storage unit 44 as deterioration information, and the deterioration information. The discharge lamp driving unit 230 is controlled so that the drive current I is supplied to the discharge lamp 90 with a current gradient based on the above. Therefore, according to the present embodiment, the current gradient of the drive current I in the transition period P is set according to the deterioration state of the discharge lamp 90. As a result, it is possible to suppress damage to the discharge lamp 90 while suppressing an increase in startup time. In addition, the risk of the discharge disappearing can be suppressed. Therefore, according to the present embodiment, it is possible to obtain a discharge lamp driving device that can suppress an increase in start-up time and sufficiently improve the life of the discharge lamp.

  Further, according to the present embodiment, since the current value of the drive current I is set to increase stepwise in each transition period Pa, Pb, Pc, Pd of the transition period P, the control of the drive current I is performed. Is simple.

  Moreover, according to this embodiment, since the discharge lamp lighting device 10 described above is provided, a light source device and a projector that can improve the life of the discharge lamp 90 are obtained.

  In the present embodiment, the following configuration may be employed.

  In the present embodiment, the timing at which the deterioration information is stored in the storage unit 44 may not be just before the discharge lamp 90 is turned off. In the present embodiment, for example, when the lamp voltage value in the steady lighting state is used as the deterioration information, the lamp voltage value is updated in the storage unit 44 every predetermined time after the discharge lamp 90 is in the steady lighting state. It is good also as a structure which memorizes.

  In the present embodiment, two or more pieces of information may be used in combination as deterioration information. In the present embodiment, for example, as deterioration information, the cumulative lighting time of the discharge lamp 90 and the lamp voltage value in the steady lighting state are combined, and an optimum startup sequence is determined from each value. Also good.

  Moreover, when using the cumulative lighting time of the discharge lamp 90 as deterioration information in this embodiment, it is good also as a structure which memorize | stores in the memory | storage part 44 separately for every lighting mode. For example, when the low power mode (eco mode) that lowers the power supplied to the discharge lamp 90 is used as the lighting mode, the discharge lamp 90 is less likely to deteriorate than the normal lighting mode. Therefore, the cumulative lighting time in the normal lighting mode and the cumulative lighting time in the low power mode are stored separately, and the degree of deterioration is determined by considering the cumulative lighting time in each lighting mode. A more appropriate startup sequence can be set.

  In the above-described embodiment, the case where the transition period P has four periods from the transition period Pa to the transition period Pd has been described, but the present invention is not limited to this. In the present embodiment, the transition period P may have two or more and three or less periods, or may have five or more periods.

  Further, in the embodiment described above, in the transition period P, the configuration is such that the current value of the drive current I increases step by step for each transition period, but is not limited thereto. In this embodiment, for example, the current value of the drive current I increases linearly or in a curve in each transition period, and the current gradient of the current value varies for each transition period. Also good. In the present embodiment, the current value of the drive current I may increase with a constant current gradient throughout the entire transition period P.

  In the embodiment described above, as one aspect of the present invention, the light source device including the discharge lamp lighting device and the projector including the light source device are shown, but the invention is not limited thereto. The equipment to which the discharge lamp lighting device of the present invention is applied is not particularly limited.

In this example, the effect of the present embodiment described above was verified by comparison with a comparative example.
In this example, an ultra-high pressure mercury lamp rated at 280 W was used as the discharge lamp. In this embodiment, the cumulative lighting time is used as the deterioration information. In this embodiment, the start-up sequence at the start of lighting is switched to three stages of an initial sequence, a second period sequence, and a third period sequence according to the cumulative lighting time of the discharge lamp. Specifically, when the cumulative lighting time is less than 1000 hours, the initial sequence, the cumulative lighting time is 1000 hours or more, and when it is shorter than 2000 hours, the second period sequence, the cumulative lighting time is 2000 hours or more. In some cases, it was set to be the third phase sequence. In each sequence, the transition period includes four transition periods Pa, Pb, Pc, and Pd.

  In the initial sequence, the driving current in the transition period Pa has a frequency of 60 kHz, a current value of 2 A, the driving current in the transition period Pb has a frequency of 1 kHz, a current value of 2.5 A, and the driving current in the transition period Pc has a frequency Is 1 kHz, the current value is 3 A, and the driving current in the transition period Pd is set so that the frequency is 280 Hz and the current value is 4 A. In the initial sequence, the transition period Pa is 2 seconds, the transition period Pb is 2 seconds, the transition period Pc is 3 seconds, and the transition period Pd is 65 seconds. Set.

The second period sequence differs from the initial sequence in that the length of the transition period Pa is 3 seconds and the length of the transition period Pb is 5 seconds.
The third period sequence differs from the initial sequence in that the length of the transition period Pa is 4 seconds and the length of the transition period Pb is 7 seconds.

  The comparative example was set so that the discharge lamp was always lit in the initial sequence regardless of the cumulative lighting time of the discharge lamp.

The discharge lamps of Examples and Comparative Examples were each lit for 4000 hours, and the presence or absence of discharge marks on the inner wall of the discharge lamp was observed. The discharge mark is a mark generated due to a large discharge energy when a discharge is generated between the electrode and the inner wall of the tube.
Moreover, it measured about the average illumination intensity maintenance factor (%) of the discharge lamp when the discharge lamp of an Example and a comparative example was each lighted for 4000 hours. The average illuminance maintenance rate was the ratio of the average illuminance when the discharge lamp was lit for 4000 hours to the average illuminance in the initial state of the discharge lamp. The average illuminance maintenance factor corresponds to the life of the discharge lamp. The observation and measurement results are shown in Table 1.

  From Table 1, it was confirmed that in the comparative example, a discharge mark was generated on the inner wall of the discharge lamp, whereas in the example, no discharge mark was generated. From this, it was confirmed that in this example, even when the discharge lamp deteriorates, it is possible to suppress an increase in current when the discharge state is unstable, and to suppress damage to the discharge lamp.

  Moreover, in the comparative example, while the average illuminance maintenance rate was significantly reduced, it was confirmed that in the examples, the decrease in the average illuminance maintenance rate was suppressed. From this, it was confirmed that according to the present embodiment, the life of the discharge lamp can be sufficiently improved.

  DESCRIPTION OF SYMBOLS 10 ... Discharge lamp lighting device (discharge lamp drive device), 40 ... Control part, 44 ... Memory | storage part, 90 ... Discharge lamp, 200 ... Light source device, 230 ... Discharge lamp drive part, 330R, 330G, 330B ... Liquid crystal light valve ( (Light modulation element), 350 ... projection optical system, 500 ... projector, I ... drive current, P, Pa, Pb, Pc, Pd ... transition period, TE, TS ... time point

Claims (7)

A discharge lamp driving unit for supplying a driving current for driving the discharge lamp to the discharge lamp;
A storage unit for storing deterioration information of the discharge lamp;
A control unit for controlling the discharge lamp driving unit;
With
The control unit is based on the deterioration information stored in the storage unit in a transition period from the time when dielectric breakdown occurs between the electrodes of the discharge lamp to the time when the discharge lamp shifts to a steady lighting state. A discharge lamp driving device that controls the discharge lamp driving section so as to increase the driving current with a current gradient.   2. The discharge lamp driving device according to claim 1, wherein the control unit controls the discharge lamp driving unit so as to increase the driving current stepwise in the transition period. The deterioration information includes a cumulative lighting time of the discharge lamp,
3. The discharge lamp driving device according to claim 1, wherein the control unit controls the discharge lamp driving unit so that the current gradient becomes gentler as the cumulative lighting time is longer in the transition period. 4. The deterioration information includes a voltage value applied between the electrodes of the discharge lamp in the steady lighting state,
The discharge lamp according to any one of claims 1 to 3, wherein the control unit controls the discharge lamp driving unit so that the current gradient becomes gentler as the voltage value is larger in the transition period. Drive device. A discharge lamp that emits light;
The discharge lamp driving device according to any one of claims 1 to 4,
A light source device comprising: A light source device according to claim 5;
A light modulation element that modulates light emitted from the light source device according to a video signal;
A projection optical system that projects the light modulated by the light modulation element onto the projection surface;
A projector comprising: A discharge lamp driving method for driving a discharge lamp by supplying a driving current,
The drive current is increased with a gradient based on the deterioration information of the discharge lamp in a transition period after the dielectric breakdown occurs between the electrodes of the discharge lamp and until the discharge lamp transitions to a steady lighting state. A discharge lamp driving method comprising controlling the discharge lamp.

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