JP5304858B2 - Discharge lamp driving device and driving method, light source device, projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technology capable of prolonging the life of a discharge lamp. <P>SOLUTION: A drive device 600 includes: a lighting circuit 620 for supplying an AC current to electrodes 520a, 520b; a current control part 712 for controlling the AC current supplied from the lighting circuit 620; a deformation detection part 722 for detecting deformation of the surface shape in the electrodes 520a, 520b; a current modulation part 732 for modulating the AC current when the deformation of the surface shape is detected; a modulation enhancement part 733 for increasing a modulation ratio by which the AC current is modulated when the deformation of the surface shape is detected while modulating the AC current. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a technique for driving a discharge lamp.

  As a discharge lamp used as a light source of a projector (projection apparatus), a high-intensity discharge lamp (HID lamp [High Intensity Discharge Lamp]) such as a high-pressure mercury lamp, a metal halide lamp, or a high-pressure sodium lamp is known. Generally, a discharge lamp in a projector is supplied with an alternating current (alternating current) and emits light by arc discharge generated between two electrodes. Each electrode of the discharge lamp is provided with a projection serving as an arc starting point in order to stabilize arc discharge between the electrodes. The reduction or disappearance of the protrusions on the electrode causes flicker and arc jump. Flicker is a phenomenon in which the light emitted from the discharge lamp flickers when the starting point of the arc moves irregularly, and the arc jump is caused by the movement of the starting point of the arc to increase the arc length. This is a phenomenon in which the illuminance of emitted light decreases.

  Conventionally, in order to prevent reduction and disappearance of the protrusions that cause flicker and arc jump, techniques for maintaining the protrusions by adjusting the temperature of the electrodes (Patent Documents 1 to 5) have been proposed. .

JP 2005-327744 A JP 2004-39563 A JP 2006-120654 A International Publication No. 2004/066687 Pamphlet JP 2003-264094 A

  However, with the conventional technology, although the projection of the electrode can be maintained, as the lighting time of the discharge lamp increases, irregularities occur on the surface of the projection, and the projection deforms due to the irregularities. was there. The deformation of the protrusion due to the unevenness causes flicker and arc jump, as with the reduction or disappearance of the protrusion.

  An object of the present invention is to provide a technique capable of extending the life of a discharge lamp based on the above-described problems.

SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.
A driving device for driving a discharge lamp that emits light by arc discharge generated between first and second electrodes,
A lighting circuit for supplying an alternating current to the first and second electrodes;
A current control unit for controlling an alternating current supplied from the lighting circuit;
A deformation detector that detects deformation of the surface shape of the first and second electrodes;
A current modulation unit that modulates an alternating current controlled by the current control unit when the deformation of the surface shape is detected by the deformation detection unit;
Modulation enhancement that increases the modulation ratio at which the current modulation unit modulates the alternating current when the deformation detection unit detects the deformation of the surface shape while the alternating current is modulated by the current modulation unit Department and
With
The current control unit repeatedly fluctuates up and down the anode duty ratio, which is the ratio of the anode period during which the first and second electrodes operate as anodes, and in synchronization with the up and down switching of the anode duty ratio, The alternating current supplied from the lighting circuit is controlled by expanding or contracting a polarity switching cycle for alternately switching the polarity of the alternating current.

  Application Example 1 A drive device according to Application Example 1 is a drive device that drives a discharge lamp that emits light by arc discharge generated between a first electrode and a second electrode. The drive device is applied to the first electrode and the second electrode. A lighting circuit that supplies an alternating current, a current control unit that controls the alternating current supplied from the lighting circuit, a deformation detection unit that detects a deformation of the surface shape of the first and second electrodes, and the deformation detection When the deformation of the surface shape is detected by the part, the deformation detection is performed while the alternating current controlled by the current controller is modulated, and the alternating current is modulated by the current modulator. When the deformation of the surface shape is detected by a section, the current modulation section includes a modulation enhancement section that increases a modulation ratio for modulating the alternating current. According to the driving device of Application Example 1, the modulation ratio of the alternating current supplied to these electrodes can be increased in accordance with the deformation of the surface shape of the first and second electrodes. Thus, the first and second electrodes can be repaired while preventing the first and second electrodes from being insufficiently melted and excessively melted. As a result, the life of the discharge lamp can be extended.

  Application Example 2 In the driving device of Application Example 1, each of the first and second electrodes includes a rod-shaped shaft portion extending toward the other electrode, and the shaft portion facing the other electrode. A lump portion formed on the tip of the lump and having a larger diameter than the shaft portion, and a protrusion portion that is formed in the lump portion near the other electrode and protrudes toward the other electrode, The deformation detection unit detects a deformation due to unevenness smaller than the protrusion formed on the surface of the protrusion in the first and second electrodes as the deformation of the surface shape, and the current modulation unit By modulating the alternating current controlled by the current control unit, the unevenness formed on the protrusions in at least one of the first and second electrodes may be melted. According to the driving device of the application example 2, it is possible to melt the unevenness formed in the protrusions while maintaining the shape of the protrusions in the first and second electrodes. As a result, it is possible to prevent the protrusions from being reduced or lost due to excessive melting.

[Application Example 3] The driving device according to Application Example 1 or Application Example 2 further includes a deterioration detection unit that detects a progress of deterioration in the first and second electrodes, and a deterioration detected by the deterioration detection unit. A modulation suppression unit that suppresses an increase in the modulation ratio by the modulation enhancement unit may be provided according to the progress state. According to the driving device of the application example 3, the surface shapes of the first and second electrodes can be repaired according to the melting characteristics that are different depending on the progress of deterioration.

  Application Example 4 In the driving device according to any one of Application Examples 1 to 3, the deformation detection unit detects the deformation of the surface shape while the alternating current is modulated by the current modulation unit. If not, a current demodulating unit that restores the alternating current modulated by the current modulating unit may be provided. According to the driving device of the application example 4, it is possible to prevent the first and second electrodes from being excessively melted.

  [Application Example 5] In the driving device according to Application Example 1 to Application Example 4, the current modulation unit is connected to the electrode during an anode period in which one of the first and second electrodes operates as an anode. A first modulation unit that increases the supplied power energy may be included. According to the driving device of Application Example 5, the surface of one electrode can be selectively melted.

  Application Example 6 In the driving device according to Application Example 5, the first modulation unit is configured to extend an anode period in which the one electrode operates as an anode, and a current value supplied to the one electrode during the anode period. The power energy supplied to the one electrode may be increased by executing at least one of the increases. According to the driving device of the application example 6, it is possible to increase the power energy supplied to one electrode by relatively easy control.

  Application Example 7 In the driving device according to Application Example 1 to Application Example 6, the current modulation unit may be applied to the electrode during an anode period in which one of the first and second electrodes operates as an anode. A second modulation unit that unevenly distributes the supplied power energy in the latter half of the anode period may be included. According to the driving device of Application Example 7, the surface of one electrode can be selectively melted.

  Application Example 8 In the driving device according to Application Example 1 to Application Example 7, the current control unit has an anode duty ratio that is a ratio of an anode period in which the first and second electrodes operate as anodes, respectively. The alternating current supplied from the lighting circuit is controlled by changing the polarity switching cycle for alternately switching the polarity of the alternating current in synchronism with the vertical switching of the anode duty ratio. May be. According to the driving device of Application Example 8, by controlling the increase in the anode duty ratio and the shortening of the polarity switching period that promote the growth of the protrusion according to the characteristics of the first and second electrodes, Reduction and disappearance can be prevented.

  Application Example 9 The light source device of Application Example 9 is a light source device that emits light, and includes a discharge lamp that emits light by arc discharge generated between first and second electrodes, and the first and second light sources. A lighting circuit that supplies an alternating current to the electrodes, a current control unit that controls the alternating current supplied from the lighting circuit, a deformation detection unit that detects a deformation of the surface shape of the first and second electrodes, When the deformation of the surface shape is detected by the deformation detection unit, a current modulation unit that modulates the alternating current controlled by the current control unit, and while the alternating current is modulated by the current modulation unit, When the deformation of the surface shape is detected by the deformation detection unit, the current modulation unit includes a modulation enhancement unit that increases a modulation ratio for modulating the alternating current. According to the light source device of Application Example 9, it is possible to repair the first and second electrodes while preventing insufficient melting and excessive melting of the first and second electrodes.

  Application Example 10 The projector according to Application Example 10 is a projector that projects an image, and emits light by arc discharge generated between the first and second electrodes as a light source of projection light that expresses the image. An electric lamp, a lighting circuit that supplies an alternating current to the first and second electrodes, a current control unit that controls the alternating current supplied from the lighting circuit, and the surface shape of the first and second electrodes A deformation detection unit for detecting deformation, a current modulation unit for modulating an alternating current controlled by the current control unit when the deformation of the surface shape is detected by the deformation detection unit, and the alternating current by the current modulation unit If a deformation of the surface shape is detected by the deformation detection unit while the current is being modulated, the current modulation unit increases a modulation ratio for modulating the alternating current. Characterized in that it comprises a modulation augment that. According to the projector of Application Example 10, the first and second electrodes can be repaired while preventing the first and second electrodes from being insufficiently melted and excessively melted.

  Application Example 11 The driving method of Application Example 11 is a driving method for driving a discharge lamp that emits light by arc discharge generated between the first and second electrodes, and is applied to the first and second electrodes. When an alternating current is supplied, deformation of the surface shape of the first and second electrodes is detected, and the deformation of the surface shape is detected, the alternating current supplied to the first and second electrodes is modulated. When the deformation of the surface shape is detected while the alternating current is being modulated, the modulation ratio for modulating the alternating current is increased. According to the driving method of the application example 11, the first and second electrodes can be repaired while preventing the first and second electrodes from being insufficiently melted and excessively melted.

  The form of the present invention is not limited to the driving device, the light source device, the projector, and the driving method. For example, the present invention is applied to other forms such as a system including a projector and a program for causing a computer to realize a function of driving a discharge lamp. You can also Further, the present invention is not limited to the above-described embodiments, and it is needless to say that the present invention can be implemented in various forms without departing from the spirit of the present invention.

It is explanatory drawing which mainly shows the structure of a projector. It is explanatory drawing which shows the detailed structure of the light source device in a projector. It is explanatory drawing which shows the detailed structure of an electrode. It is explanatory drawing which shows a mode that the unevenness | corrugation was formed in the electrode. It is explanatory drawing which mainly shows the detailed structure of the drive device in a light source device. It is a flowchart which shows the lighting process which a drive device performs. It is explanatory drawing which shows an example of the alternating current supplied to an electrode in normal mode. It is explanatory drawing which shows an example of the alternating current supplied to an electrode in repair mode. It is explanatory drawing which shows the experimental result which supplied the alternating current to the electrode by changing the anode duty ratio. It is explanatory drawing which shows an example of the alternating current supplied to an electrode in the repair mode of a 1st modification. It is explanatory drawing which shows the experimental result which supplied the alternating current to the electrode by changing the bias ratio of an anode period. It is explanatory drawing which shows an example of the alternating current supplied to an electrode in the repair mode of a 2nd modification. It is explanatory drawing which shows an example of a mode that an anode duty ratio and a drive frequency are fluctuate | varied in the normal mode of a 3rd modification.

  In order to further clarify the configuration and operation of the present invention described above, a projector as a projection apparatus to which the present invention is applied will be described below.

A. Example:
A1. Projector configuration:
FIG. 1 is an explanatory diagram mainly showing the configuration of the projector 10. The projector 10 projects an image on the screen 80. The screen 80 is a plane on which an image is displayed, and may be a projection screen or a wall surface.

  The projector 10 includes a light source device 20, a projection optical system 30, and a projection optical system 40. The light source device 20 of the projector 10 emits light as a light source, and the light emitted from the light source device 20 is supplied to the projection optical system 30. Details of the light source device 20 will be described later.

  The projection optical system 30 of the projector 10 generates projection light that expresses an image from the light supplied from the light source device 20. Projection light generated by the projection optical system 30 is sent to the projection optical system 40. In this embodiment, the projection optical system 30 is a color separation / combination optical system, which separates the light supplied from the light source device 20 into red light, green light, and blue light, and modulates them with three spatial light modulators. After that, the projection light is generated by combining these lights into one light again. In this embodiment, the number of spatial light modulators is three, but in other embodiments, it may be three or less, or may be three or more. In this embodiment, the spatial light modulator is a transmissive liquid crystal panel that modulates transmitted light, but in other embodiments, a reflective liquid crystal panel that modulates reflected light may be used, or a digital micro- A micromirror light modulator such as a mirror device (Digital Micromirror Device, DMD (registered trademark)) may be used.

  The projection optical system 40 of the projector 10 projects the projection light generated by the projection optical system 30 onto the screen 80. In this embodiment, the projection optical system 40 is a projection lens unit in which a plurality of lenses such as a front lens, a zoom lens, a master lens, and a focus lens are arranged. The projection optical system 40 is not limited to the projection lens unit, and the projection generated by the projection optical system 30 using at least one of an aspheric lens, a magnifying lens, a diffusing glass, an aspheric mirror, and a reflection mirror. An optical system that reflects light to the screen 80 may be used.

A2. Detailed configuration of the light source device:
FIG. 2 is an explanatory diagram showing a detailed configuration of the light source device 20 in the projector 10. The light source device 20 includes a light source unit 210 and a driving device 600. The light source unit 210 of the light source device 20 includes a main reflecting mirror 212, a sub reflecting mirror 214, and a discharge lamp 500.

  The discharge lamp 500 of the light source unit 210 includes an arc tube 510, electrodes 520a and 520b, conductive members 530a and 530b, and electrode terminals 540a and 540b. The discharge lamp 500 is driven by the driving device 600 and emits light by arc discharge generated between the electrode 520a which is the first electrode and the electrode 520b which is the second electrode. Details of the driving device 600 will be described later.

  The arc tube 510 of the discharge lamp 500 is a quartz glass tube having translucency and having a spherical central portion, and a discharge medium such as a rare gas, mercury, or a metal halide compound is disposed in the central portion of the arc tube 510. A discharge space portion 512 in which a gas containing gas is enclosed is formed.

  The electrodes 520 a and 520 b of the discharge lamp 500 are spaced apart from the discharge space portion 512 of the arc tube 510 and generate arc discharge inside the discharge space portion 512 of the arc tube 510. In this embodiment, the electrodes 520a and 520b are made of tungsten. Details of the electrodes 520a and 520b will be described later.

  The conductive member 530a of the discharge lamp 500 is a conductor that electrically connects the electrode 520a and the electrode terminal 540a, and the conductive member 530b of the discharge lamp 500 is a conductive material that electrically connects the electrode 520b and the electrode terminal 540b. Is the body. In this embodiment, the conductive members 530 a and 530 b are molybdenum foils and are sealed in the arc tube 510.

  The electrode terminals 540a and 540b of the discharge lamp 500 are conductors that introduce an alternating current supplied from the driving device 600 into the electrodes 520a and 520b, and are provided at both ends of the arc tube 510, respectively.

  The main reflecting mirror 212 of the light source unit 210 has a concave reflecting surface. The main reflecting mirror 212 is provided at the end of the discharge lamp 500 on the electrode 520a side, and reflects the light emitted from the discharge lamp 500 to the projection optical system 30. In the present embodiment, the reflecting surface of the main reflecting mirror 212 is a spheroid, but may be a paraboloid in other embodiments. In the present embodiment, the main reflecting mirror 212 is made of quartz glass, but may be made of crystallized glass in other embodiments.

  The sub-reflecting mirror 214 of the light source unit 210 has a hemispherical reflecting surface smaller than the main reflecting mirror 212. The sub-reflecting mirror 214 is provided on the center electrode 520b side where the discharge space portion 512 is formed in the discharge lamp 500, and the main reflector reflects light emitted from the discharge lamp 500 to the electrode 520b side. Reflect to 212. In this embodiment, the sub-reflecting mirror 214 is made of quartz glass, but in other embodiments, it may be made of crystallized glass.

  FIG. 3 is an explanatory diagram showing a detailed configuration of the electrodes 520a and 520b. The electrodes 520a and 520b include shaft portions 521a and 521b, coil portions 523a and 523b, block portions 524a and 524b, and projection portions 526a and 526b. The shaft portions 521a and 521b are rod-shaped tungsten members extending toward the other electrodes 520b and 520a. By winding a tungsten wire around the ends of the shaft portions 521a and 521b and heating and melting the tips, incompletely melted portions of the tungsten wire are formed as coil portions 523a and 523b. Of these, completely melted portions are formed as the block portions 524a and 524b. The massive portions 524a and 524b are formed at the tips of the shaft portions 521a and 521b facing the other electrodes 520b and 520a, and have a larger diameter than the shaft portions 521a and 521b. The protrusions 526a and 526b are formed in the massive portions 524a and 524b in the vicinity of the other electrodes 520b and 520a, and project toward the other electrodes 520b and 520a.

  FIG. 4 is an explanatory diagram showing a state in which the unevenness 529 is formed on the electrode 520a. Although FIG. 4 shows a state in which the unevenness 529 is formed on the electrode 520a, the unevenness 529 is similarly formed on the electrode 520b. In general, as the accumulated time for lighting the discharge lamp 500 increases, irregularities 529 smaller than the protrusions 526a and 526b are formed on the surfaces of the protrusions 526a and 526b of the electrodes 520a and 520b. When the protrusions 526a and 526b are deformed by the unevenness 529, the starting point of the arc generated between the electrodes 520a and 520b moves to the unevenness 529, and flicker and arc jump occur. In this embodiment, when the projections 526a and 526b of the electrodes 520a and 520b are formed with the unevenness 529, the alternating current supplied to the electrodes 520a and 520b is modulated by the driving device 600. Accordingly, the projections 526a and 526b can be repaired by melting the unevenness 529 while the discharge lamp 500 is turned on.

A3. Detailed configuration of drive unit:
FIG. 5 is an explanatory diagram mainly showing a detailed configuration of the driving device 600 in the light source device 20. The drive device 600 includes a drive control unit 610, a lighting circuit 620, a deformation sensor 632, and a deterioration sensor 634.

  The lighting circuit 620 of the driving device 600 is an electric circuit including an igniter circuit that starts the discharge lamp 500 and an inverter circuit that generates an alternating current that drives the discharge lamp 500, and based on an instruction from the drive control unit 610, An alternating current is supplied to the electrodes 520a and 520b of the discharge lamp 500.

  The drive control unit 610 of the drive device 600 is an electric circuit that controls the operation of the lighting circuit 620, and includes a startup control unit 711, a current control unit 712, a deformation detection unit 722, a deterioration detection unit 724, and a current modulation unit. 732, a modulation enhancement unit 733, a modulation suppression unit 734, and a current demodulation unit 736.

  The start control unit 711 of the drive control unit 610 executes control for starting the discharge lamp 500 by outputting a control signal to the lighting circuit 620. The current control unit 712 of the drive control unit 610 controls the alternating current supplied from the lighting circuit 620 in the normal mode by outputting a control signal to the lighting circuit 620 after the discharge lamp 500 is started by the start control unit 711. To do. Details of the alternating current in the normal mode will be described later.

  The deformation detection unit 722 of the drive control unit 610 outputs the deformation of the surface shape of the electrodes 520a and 520b, that is, the deformation of the projections 526a and 526b due to the unevenness 529 formed on the electrodes 520a and 520b, as an output signal from the deformation sensor 632. Detect based on In the present embodiment, the deformation sensor 632 is a current sensor that detects an alternating current supplied to the electrodes 520a and 520b, and the deformation detection unit 722 detects fluctuations in the current value due to flicker or arc jump generated by the unevenness 529. This is detected as a deformation of the surface shape of the electrodes 520a and 520b. In other embodiments, an image sensor may be used as the deformation sensor 632 to detect deformation of the electrodes 520a and 520b based on image analysis, or an illumination sensor may be used as the deformation sensor 632 to emit from the discharge lamp 500. The deformation of the electrodes 520a and 520b may be detected based on the fluctuation of the illuminance.

  The current modulation unit 732 of the drive control unit 610 modulates the alternating current in the normal mode controlled by the current control unit 712 when the deformation detection unit 722 detects the deformation of the protrusions 526a and 526b. The alternating current supplied from 620 is controlled in the repair mode. The repair mode by the current modulation section 732 is a mode in which the projections 526a and 526b are repaired by modulating the alternating current supplied to the electrodes 520a and 520b to melt the unevenness 529 while the discharge lamp 500 is lit. is there. Details of the alternating current in the repair mode will be described later.

  When the deformation detection unit 722 detects deformation of the protrusions 526a and 526b while the current modulation unit 732 modulates the alternating current, the modulation enhancement unit 733 of the drive control unit 610 detects that the current modulation unit 732 is normal. The modulation ratio, which is the ratio for modulating the alternating current from the mode to the repair mode, is increased.

  The deterioration detection unit 724 of the drive control unit 610 detects the progress of deterioration in the electrodes 520 a and 520 b based on the output signal from the deterioration sensor 634. In the present embodiment, the deterioration sensor 634 is a voltage sensor that detects the voltage between the electrodes 520a and 520b, and the deterioration detection unit 724 is based on the voltage between the electrodes 520a and 520b, and the progress of deterioration of the electrodes 520a and 520b. Detect the situation. In general, as the accumulated time for lighting the discharge lamp 500 increases, the tips of the electrodes 520a and 520b are consumed. When the tips of the electrodes 520a and 520b are consumed, the distance between the electrodes 520a and 520b increases, and the voltage between the electrodes 520a and 520b increases. In another embodiment, the progress of deterioration in the electrodes 520a and 520b may be detected based on the accumulated time when the discharge lamp 500 is lit using a timer for the deterioration sensor 634.

  The modulation suppression unit 734 of the drive control unit 610 suppresses an increase in the modulation ratio by the modulation enhancement unit 733 in accordance with the progress of deterioration detected by the deterioration detection unit 724.

  The current demodulating unit 736 of the drive control unit 610 is modulated by the current modulating unit 732 when the deformation detecting unit 722 does not detect deformation of the electrodes 520a and 520b while the alternating current is modulated by the current modulating unit 732. Restore the alternating current. That is, the current demodulator 736 changes the mode for controlling the alternating current supplied to the electrodes 520a and 520b from the repair mode to the normal mode when the protrusions 526a and 526b of the electrodes 520a and 520b are repaired during the repair mode. change.

  In this embodiment, the drive control unit 610 includes a central processing unit (hereinafter referred to as a CPU) 612 that executes various arithmetic processes, a memory 614 that stores data processed by the CPU 612, and a drive control unit. And an interface 616 for exchanging data with the outside of the network 610. In this embodiment, each function of the activation control unit 711, current control unit 712, deformation detection unit 722, deterioration detection unit 724, current modulation unit 732, modulation enhancement unit 733, modulation suppression unit 734, and current demodulation unit 736 is stored in the memory. This is realized by the CPU 612 operating based on the software stored in the computer 614. However, as another embodiment, the electronic circuit of the drive control unit 610 is realized by operating based on the physical circuit configuration. Also good.

A4. Projector operation:
FIG. 6 is a flowchart showing the lighting process (step S10) executed by the driving device 600. The lighting process (step S10) is a process of lighting the discharge lamp 500. In this embodiment, when the power of the projector 10 is turned on, the drive control unit 610 of the drive device 600 starts the lighting process (step S10).

  The drive control part 610 will perform a starting control process (step S100), if a lighting process (step S10) is started. In the start control process (step S100), the drive control unit 610 executes control for starting the discharge lamp 500 by outputting a control signal to the lighting circuit 620.

  After the discharge lamp 500 is activated by the activation control process (step S100), the drive control unit 610 executes a current control process (step S200). In the current control process (step S200), the drive control unit 610 controls the alternating current supplied from the lighting circuit 620 in the normal mode by outputting a control signal to the lighting circuit 620.

  FIG. 7 is an explanatory diagram showing an example of an alternating current supplied to the electrode 520a in the normal mode. In FIG. 7, the alternating current supplied to the electrode 520a in the normal mode is obtained by taking a positive value for the current value at which the electrode 520a operates as an anode and a negative value for the current value at which the electrode 520a operates as a cathode. Show. The electrode 520b operates as a cathode while the electrode 520a operates as an anode, and the electrode 520b operates as an anode while the electrode 520a operates as a cathode. That is, the alternating current supplied to the electrode 520b shows a mode in which the sign of the alternating current supplied to the electrode 520a is reversed.

  As shown in FIG. 7, the alternating current supplied to the electrodes 520a and 520b in the normal mode is between a positive current value “C1” and a negative current value “−C1” having the same absolute value but different positive and negative values. This is a rectangular wave whose polarity switches regularly. In the present embodiment, in the normal mode, the polarity switching cycle in which the polarity of the alternating current is alternately switched is constant at time Ts. In this embodiment, in the normal mode, the anode period in which the electrode 520a operates as an anode is constant at time Tp, and the cathode period in which the electrode 520a operates as a cathode is constant at time Tn. Are the same length. That is, in the normal mode, the anode duty ratio, which is the ratio of the anode period of the electrode 520a to the polarity switching period, is 50%.

  Returning to the description of FIG. 6, while the alternating current supplied from the lighting circuit 620 is controlled in the normal mode by the current control process (step S200), the drive control unit 610 executes the deformation detection process (step S210). To do. In the deformation detection process (step S <b> 210), the drive control unit 610 detects the deformation of the protrusions 526 a and 526 b due to the unevenness 529 formed on the electrodes 520 a and 520 b based on the output signal from the deformation sensor 632. When the deformation of the protrusions 526a and 526b is not detected in the deformation detection process (step S210) (step S220: “NO”), the drive control unit 610 continuously executes the current control process (step S200).

  On the other hand, when deformation of the protrusions 526a and 526b is detected in the deformation detection process (step S210) (step S220: “YES”), the drive control unit 610 executes a current modulation process (step S300). In the current modulation process (step S300), the drive control unit 610 modulates the alternating current in the normal mode controlled by the current control process (step S100), thereby changing the alternating current supplied from the lighting circuit 620 in the repair mode. Control. In the present embodiment, in the repair mode, the drive control unit 610 increases the anode duty ratio in which the anode period of the deformed electrode in which the deformation is detected among the electrodes 520a and 520b occupies the polarity switching period, thereby changing the deformation electrode. Increase temperature. As a result, the projections 526a and 526b are repaired by melting the unevenness 529 formed on the deformed electrode.

  FIG. 8 is an explanatory diagram showing an example of an alternating current supplied to the electrode 520a in the repair mode. FIG. 8 shows the alternating current supplied to the electrode 520a in the repair mode by taking positive and negative values as in FIG. The alternating current supplied to the electrode 520b shows a mode in which the polarity of the alternating current supplied to the electrode 520a is reversed.

  The alternating current in the repair mode shown in FIG. 8 is shown in FIG. 7 except that the anode duty ratio of the anode period of the electrode 520a occupying the polarity switching period is increased in order to repair the protrusion 526a of the electrode 520a. This is the same as the alternating current in the normal mode. In the repair mode of FIG. 8, compared with the normal mode of FIG. 7, the anode period in which the electrode 520a operates as an anode is extended from the time Tp to the time Tpc, and the cathode period in which the electrode 520a operates as a cathode is the anode period. Is reduced from time Tn to time Tnc by the amount of increase. That is, in the repair mode of FIG. 8, the anode duty ratio that the anode period of the electrode 520a occupies in the polarity switching period exceeds 50%. As a result, the power energy supplied to the electrode 520a during the anode period of the electrode 520a is larger in the repair mode than in the normal mode. When the electrode 520b is repaired instead of repairing the electrode 520a, the anode duty ratio that the anode period of the electrode 520a occupies in the polarity switching period is decreased, and the anode period of the electrode 520b occupies the polarity switching period. Increase anode duty ratio. In this embodiment, when shifting from the normal mode to the repair mode, the anode duty ratio of the deformed electrode in which the deformation is detected among the electrodes 520a and 520b is set to 55%.

  Returning to the description of FIG. 6, while the alternating current supplied from the lighting circuit 620 is controlled in the modulation mode by the current modulation process (step S300), the drive control unit 610 executes the deformation detection process (step S310). To do. In the deformation detection process (step S <b> 310), the drive control unit 610 detects the deformation of the protrusions 526 a and 526 b due to the unevenness 529 formed on the electrodes 520 a and 520 b based on the output signal from the deformation sensor 632.

  If deformation of the protrusions 526a and 526b is not detected in the deformation detection process (step S310), that is, if the protrusions 526a and 526b of the electrodes 520a and 520b are repaired during the repair mode (step S322: “NO”), driving is performed. Control unit 610 executes current demodulation processing (step S320). In the current demodulation process (step S320), the drive control unit 610 shifts the control mode from the repair mode by the current modulation process (step S300) to the normal mode by the current control process (step S200).

  On the other hand, when deformation of the protrusions 526a and 526b is detected in the deformation detection process (step S310), that is, when the protrusions 526a and 526b of the electrodes 520a and 520b are not repaired during the repair mode (step S322: “YES” ]), The drive control unit 610 executes a modulation enhancement process (step S500). In the modulation enhancement process (step S500), the drive control unit 610 increases a modulation ratio that is a ratio for modulating the alternating current from the normal mode to the repair mode. In the present embodiment, the anode duty ratio of the deformed electrode in which the deformation is detected in the electrodes 520a and 520b in the modulation enhancement process (step S500) is 1% each time the deformation is detected in the deformation detection process (step S310). Increased by one.

  While the alternating current supplied from the lighting circuit 620 is controlled in the modulation mode by the current modulation process (step S300), the drive control unit 610 executes the deterioration detection process (step S410). In the deterioration detection process (step S410), the drive control unit 610 detects the progress of deterioration in the electrodes 520a and 520b based on the output signal from the deterioration sensor 634. In the present embodiment, in the deterioration detection process (step S410), the drive control unit 610 calculates the life expectancy of the electrodes 520a and 520b based on the output signal from the deterioration sensor 634, and the electrode 520a whose life expectancy exceeds half of the assumed life. , 520b are determined as “initial products”, and the electrodes 520a and 520b whose lifetime is less than half of the assumed lifetime are determined as “deteriorated products”.

  After the deterioration detection process (step S410), the drive control unit 610 executes a modulation suppression process (step S420). In the modulation suppression process (step S420), the drive control unit 610 suppresses an increase in the modulation ratio due to the modulation enhancement process (step S500) according to the progress of deterioration detected in the deterioration detection process (step S410).

  FIG. 9 is an explanatory diagram showing an experimental result in which an alternating current is supplied to the electrodes 520a and 520b while changing the anode duty ratio. In the experiment of FIG. 9, “initial product” electrodes 520 a and 520 b whose life expectancy exceeds half of the assumed life and “degraded product” electrodes 520 a and 520 b whose life expectancy period is less than half of the assumed life are prepared. An alternating current having a changed duty ratio was supplied, and the state where these electrodes were melted was observed.

  When the anode duty ratio was 50%, the protrusions 526a and 526b were not melted in both the initial product and the deteriorated product. When the anode duty ratio is 55%, in the initial product, the surface of the protrusions 526a and 526b is melted and the unevenness 529 generated in the protrusions 526a and 526b disappears, but the protrusions 526a, 526a, 526a, 526a, The shape change of 526b itself was not observed, but in the deteriorated product, the protrusions 526a and 526b that did not have the unevenness 529 were not melted. When the anode duty ratio is 60%, the surface of the protrusions 526a and 526b melts in both the initial product and the deteriorated product, and the unevenness 529 generated in the protrusions 526a and 526b disappears, but the arc discharge start point cannot be determined. No change in shape of the projections 526a and 526b itself was observed. When the anode duty ratio is 65%, in the initial product, not only the melting of the unevenness 529 but also the shape change that can be repaired by melting is observed in the protrusions 526a and 526b, the arc starting point of the arc becomes uncertain, or the arc length is desired In the deteriorated product, the surface of the protrusions 526a and 526b is melted and the unevenness 529 generated in the protrusions 526a and 526b is eliminated. There was no change in the shape of the protrusions 526a and 526b themselves that would become indefinite. When the anode duty ratio is 70%, in the initial product, not only the discharge point of the arc is determined, but also the projections 526a and 526b are melted by the length of the arc so that the light utilization efficiency in the subsequent optical system is lowered. While a shape change that cannot be repaired was observed, in a deteriorated product, not only the unevenness 529 was melted but also the shape change that could be repaired by melting was observed on the protrusions 526a and 526b, and the arc discharge starting point could not be determined. Began to become longer than desired.

  In this embodiment, based on the experimental results shown in FIG. 9, in the modulation suppression process (step S420), the drive control unit 610 determines that the modulation enhancement process is performed when the deterioration detection process (step S410) determines that the product is an initial product. An increase in anode duty ratio by (step S500) is allowed up to 60%, and an anode duty ratio increase by modulation enhancement process (step S500) is increased to 65% when the deterioration detection process (step S410) determines a deteriorated product. Allow.

A5. effect:
According to the drive device 600 described above, by performing the modulation enhancement process (step S500) in the repair mode, the drive device 600 is supplied to the electrodes 520a and 520b according to the deformation of the protrusions 526a and 526b of the electrodes 520a and 520b. The modulation ratio of the alternating current can be increased. Thus, the protrusions 526a and 526b deformed by the unevenness 529 can be repaired while preventing the protrusions 526a and 526b from being insufficiently melted and excessively melted. As a result, the life of the discharge lamp 500 can be extended.

  Further, the modulation suppression process (step S420) suppresses an increase in the modulation ratio of the alternating current supplied to the electrodes 520a and 520b in accordance with the progress of deterioration of the electrodes 520a and 520b. The protrusions 526a and 526b of the electrodes 520a and 520b can be repaired in accordance with different melting characteristics.

  Further, by executing the current demodulation process (step S320) in the repair mode, when the protrusions 526a and 526b of the electrodes 520a and 520b are repaired, the control mode is shifted from the repair mode to the normal mode. Excessive melting of 526a and 526b can be prevented.

B. First modification:
The driving device 600 of the first modified example is the same as the above-described embodiment except that the waveform of the alternating current modulated in the repair mode is different.

  FIG. 10 is an explanatory diagram showing an example of an alternating current supplied to the electrode 520a in the repair mode of the first modification. FIG. 10 shows the alternating current supplied to the electrode 520a in the repair mode by taking positive and negative values as in FIG. The alternating current supplied to the electrode 520b shows a mode in which the polarity of the alternating current supplied to the electrode 520a is reversed.

  The alternating current in the repair mode shown in FIG. 10 is that the power energy supplied to the electrode 520a during the anode period of the electrode 520a is unevenly distributed in the latter half of the anode period in order to repair the protrusion 526a of the electrode 520a. Except for this, it is the same as the alternating current in the normal mode shown in FIG. In the repair mode of FIG. 10, the values of the anode period, the cathode period, and the polarity switching period are the same as those in the normal mode of FIG. 7, and the power energy supplied to the electrode 520a during the anode period is also shown in FIG. The current value in the anode period gradually increases from the current value “Ca” smaller than the current value “C1” to the current value “Cb” larger than the current value “C1”. When repairing the electrode 520b instead of repairing the electrode 520a, the power energy supplied to the electrode 520b during the anode period of the electrode 520b is unevenly distributed in the latter half of the anode period.

  In this embodiment, when shifting from the normal mode to the repair mode, the bias ratio between the current value “Ca” for starting the anode period and the current value “Cb” for ending the anode period is set to 20%. In this embodiment, in the modulation enhancement process (step S500), the weight ratio between the current value “Ca” for starting the anode period and the current value “Cb” for ending the anode period is changed by the deformation detection process (step S310). Each time is detected, it is increased by 1%.

  FIG. 11 is an explanatory diagram showing an experimental result in which an alternating current is supplied to the electrodes 520a and 520b while changing the weight ratio of the anode period. In the experiment of FIG. 11, “initial product” electrodes 520 a and 520 b whose life expectancy exceeds half of the assumed life and “degraded product” electrodes 520 a and 520 b whose life expectancy is less than half of the assumed life are prepared. An alternating current with varying the weight ratio of the period was supplied, and the state where these electrodes melted was observed.

  When the weight ratio was 0%, 5%, 10%, and 15%, the protrusions 526a and 526b did not melt in both the initial product and the deteriorated product. When the weight ratio is 20%, in the initial product, the surface of the protrusions 526a and 526b is melted and the unevenness 529 generated in the protrusions 526a and 526b is eliminated, but the protrusions 526a and 526b that the arc discharge starting point cannot be determined. While the shape change of itself was not observed, in the deteriorated product, the protrusions 526a and 526b were not melted so as to eliminate the unevenness 529. When the weight ratio is 25% or 30%, the surface of the protrusions 526a and 526b melts and the unevenness 529 generated in the protrusions 526a and 526b disappears in both the initial product and the deteriorated product, but the arc discharge starting point is not fixed. No change in shape was observed in the protruding portions 526a and 526b that disappeared. When the weight ratio exceeds 30%, scroll noise is generated in the light emitted from the discharge lamp 500, and thus the protrusions 526a and 526b cannot be repaired in a state where the discharge lamp 500 is normally lit.

  In the first modification, based on the experimental results shown in FIG. 11, in the modulation suppression process (step S420), the drive control unit 610 performs the modulation enhancement process (for the initial product and the deteriorated electrode 520a, 520b) An increase in the weight ratio of the anode period in step S500) is allowed up to 30%. In the first modified example, since the increase in the bias ratio is limited to 30% for both the initial and degraded electrodes 520a and 520b, the degradation detection process (step S410) may be omitted.

  According to the driving device 600 of the first modification described above, the protrusions 526a and 526b deformed by the unevenness 529 are prevented while preventing the protrusions 526a and 526b from being insufficiently melted and scroll noise, as in the above-described embodiment. Can be repaired.

C. Second modification:
The driving device 600 of the second modified example is the same as the above-described embodiment except that the waveform of the alternating current modulated in the repair mode is different.

  FIG. 12 is an explanatory diagram showing an example of an alternating current supplied to the electrode 520a in the repair mode of the second modified example. FIG. 12 shows the alternating current supplied to the electrode 520a in the repair mode by taking positive and negative values as in FIG. The alternating current supplied to the electrode 520b shows a mode in which the polarity of the alternating current supplied to the electrode 520a is reversed.

  The alternating current in the repair mode shown in FIG. 12 is the same as that in FIG. 7 except that the power energy supplied to the electrode 520a is increased during the anode period of the electrode 520a in order to repair the protrusion 526a of the electrode 520a. This is the same as the alternating current in the normal mode shown. In the repair mode of FIG. 12, each value of the anode period, the cathode period, and the polarity switching period is the same as each value in the normal mode of FIG. 7, but the current value in the anode period is larger than the current value “C1”. The value is increased to “C2”. Note that when the electrode 520b is repaired instead of repairing the electrode 520a, the current value supplied to the electrode 520b is increased during the anode period of the electrode 520b.

  In this embodiment, when shifting from the normal mode to the repair mode, the increasing rate for increasing the current value “C1” supplied during the anode period to the current value “C2” is set to 20%. In this embodiment, in the modulation enhancement process (step S500), the increase rate for increasing the current value “C1” supplied during the anode period to the current value “C2” is detected by the deformation detection process (step S310). Each time it is increased by 1%.

  According to the driving device 600 of the second modification described above, similarly to the above-described embodiment, the protrusions 526a and 526b deformed by the unevenness 529 are prevented while preventing the protrusions 526a and 526b from being insufficiently melted and excessively melted. Can be repaired.

D. Third modification:
The driving device 600 of the third modification is the same as that of the above-described embodiment except that the waveform of the alternating current in the normal mode is different. In the third modification, the drive control unit 610 repeatedly varies the anode duty ratio up and down (increase / decrease) in the normal mode, and expands / contracts the polarity switching period in synchronization with the up / down switching of the anode duty ratio. Thus, the alternating current supplied from the lighting circuit 620 is controlled. The increase in the anode duty ratio and the shortening of the polarity switching period promote the growth of the protrusions 526a and 526b in the electrodes 520a and 520b. For this reason, in the normal mode of the third modified example, the projections 526a and 526b can be prevented from being reduced or lost by controlling according to the characteristics of the electrodes 520a and 520b.

  FIG. 13 is an explanatory diagram showing an example of how the anode duty ratio and the drive frequency are changed in the normal mode of the third modified example. In FIG. 13, the anode duty ratio indicates the ratio of the anode period of the electrode 520a to the polarity switching period, and the drive frequency is the reciprocal of the polarity switching period and indicates the number of times the polarity is switched per unit time. The alternating current in the normal mode in the third modification has a waveform obtained by modulating the rectangular wave shown in FIG. 7 with the anode duty ratio and the driving frequency shown in FIG. The alternating current in the repair mode in the third modification has a waveform in which the anode duty ratio is further increased with respect to the rectangular wave modulated with the anode duty ratio and the driving frequency shown in FIG.

  As shown in FIG. 13, in the third modification, the anode duty ratio repeatedly fluctuates up and down between 30% and 80%, and the driving frequency is 100 Hz (Hertz) in synchronization with the fluctuation of the anode duty ratio. ) To 200 Hz and repeatedly fluctuate up and down. In the third modification, the electrode 520b is more likely to store heat than the electrode 520a due to the influence of the sub-reflecting mirror 214. Therefore, by setting the cumulative time during which the electrode 520a operates as an anode longer than the electrode 520b, the electrodes 520a and 520b The temperature is made uniform. In this embodiment, when the anode duty ratio becomes the maximum value and the minimum value, the drive frequency becomes the minimum value of 100 Hz, and when the anode duty ratio goes back and forth around 50%, the drive frequency is the maximum value. 200Hz.

  According to the driving device 600 of the third modified example described above, the protrusions 526a and 526b deformed by the unevenness 529 are prevented while preventing the protrusions 526a and 526b from being insufficiently melted and excessively melted, as in the above-described embodiment. Can be repaired. Further, by controlling the increase in the anode duty ratio and the shortening of the polarity switching period that promote the growth of the protrusions 526a and 526b according to the characteristics of the electrodes 520a and 520b, the protrusions 526a and 526b are prevented from being reduced or lost. can do.

E. Other embodiments:
As mentioned above, although embodiment of this invention was described, this invention is not limited to such embodiment at all, Of course, it can implement with various forms within the range which does not deviate from the meaning of this invention. is there. For example, in the repair mode, the modulation ratio for modulating the alternating current in the normal mode can be changed as appropriate according to the characteristics of the electrodes 520a and 520b. The modulation of the alternating current in the repair mode is not limited to any one of an increase in anode duty ratio, an increase in current value in the anode period, and uneven distribution of power energy in the anode period. You may combine.

DESCRIPTION OF SYMBOLS 10 ... Projector 20 ... Light source device 30 ... Projection optical system 40 ... Projection optical system 80 ... Screen 210 ... Light source unit 212 ... Main reflection mirror 214 ... Sub-reflection mirror 500 ... Discharge lamp 510 ... Light-emitting tube 512 ... Discharge space part 520a, 520b ... Electrodes 521a, 521b ... Shafts 523a, 523b ... Coils 524a, 524b ... Lumps 526a, 526b ... Protrusions 529 ... Concavities and convexities 530a, 530b ... Conductive members 540a, 540b ... Electrode terminals 600 ... Drive device 610 ... Drive controller 612 ... CPU
614 ... Memory 616 ... Interface 620 ... Lighting circuit 632 ... Deformation sensor 634 ... Degradation sensor 711 ... Start-up control unit 712 ... Current control unit 722 ... Deformation detection unit 724 ... Degradation detection unit 732 ... Current modulation unit 733 ... Modulation enhancement unit 734 ... Modulation suppression unit 736 ... Current demodulation unit

Claims (10)

A driving device for driving a discharge lamp that emits light by arc discharge generated between first and second electrodes,
A lighting circuit for supplying an alternating current to the first and second electrodes;
A current control unit for controlling an alternating current supplied from the lighting circuit;
A deformation detector that detects deformation of the surface shape of the first and second electrodes;
A current modulation unit that modulates an alternating current controlled by the current control unit when the deformation of the surface shape is detected by the deformation detection unit;
Modulation enhancement that increases the modulation ratio at which the current modulation unit modulates the alternating current when the deformation detection unit detects the deformation of the surface shape while the alternating current is modulated by the current modulation unit and a part,
The current control unit repeatedly fluctuates up and down the anode duty ratio, which is the ratio of the anode period during which the first and second electrodes operate as anodes, and in synchronization with the up and down switching of the anode duty ratio, A drive device that controls the alternating current supplied from the lighting circuit by expanding and contracting a polarity switching cycle for alternately switching the polarity of the alternating current . The drive device according to claim 1,
Each electrode in the first and second electrodes is:
A rod-shaped shaft extending toward the other electrode;
A lump portion formed at the tip of the shaft portion facing the other electrode and having a larger diameter than the shaft portion;
Protruding portions that are formed in the lump portion adjacent to the other electrode and project toward the other electrode,
The deformation detection unit detects deformation due to unevenness smaller than the protrusion formed on the surface of the protrusion in the first and second electrodes as deformation of the surface shape,
The driving device, wherein the current modulation unit melts irregularities formed on the protrusions in at least one of the first and second electrodes by modulating an alternating current controlled by the current control unit. The drive device according to claim 1 or 2, further comprising:
A deterioration detector for detecting the progress of deterioration in the first and second electrodes;
A drive unit comprising: a modulation suppression unit that suppresses an increase in the modulation ratio by the modulation enhancement unit in accordance with the progress of deterioration detected by the deterioration detection unit.   4. The driving device according to claim 1, wherein the deformation detection unit does not detect deformation of the surface shape while the alternating current is modulated by the current modulation unit. 5. In this case, a drive device including a current demodulating unit that restores the alternating current modulated by the current modulating unit.   5. The drive device according to claim 1, wherein the current modulation unit supplies the electrode during an anode period in which one of the first and second electrodes operates as an anode. 6. Drive device including a first modulation unit for increasing the power energy generated.   6. The driving apparatus according to claim 5, wherein the first modulation unit is configured to extend an anode period in which the one electrode operates as an anode, and to supply a current value supplied to the one electrode during the anode period. A driving device that increases power energy supplied to the one electrode by executing at least one of the increases.   7. The driving device according to claim 1, wherein the current modulation unit supplies the electrode during an anode period in which one of the first and second electrodes operates as an anode. The drive apparatus containing the 2nd modulation | alteration part which distributes the electric power energy performed unevenly in the latter half of this anode period. A light source device that emits light,
A discharge lamp that emits light by arc discharge generated between the first and second electrodes;
A lighting circuit for supplying an alternating current to the first and second electrodes;
A current control unit for controlling an alternating current supplied from the lighting circuit;
A deformation detector that detects deformation of the surface shape of the first and second electrodes;
A current modulation unit that modulates an alternating current controlled by the current control unit when the deformation of the surface shape is detected by the deformation detection unit;
Modulation enhancement that increases the modulation ratio at which the current modulation unit modulates the alternating current when the deformation detection unit detects the deformation of the surface shape while the alternating current is modulated by the current modulation unit and a part,
The current control unit repeatedly fluctuates up and down the anode duty ratio, which is the ratio of the anode period during which the first and second electrodes operate as anodes, and in synchronization with the up and down switching of the anode duty ratio, A light source device that controls an alternating current supplied from the lighting circuit by expanding and contracting a polarity switching cycle for alternately switching the polarity of the alternating current . A projector for projecting images,
As a light source of projection light representing the image, a discharge lamp that emits light by arc discharge generated between the first and second electrodes;
A lighting circuit for supplying an alternating current to the first and second electrodes;
A current control unit for controlling an alternating current supplied from the lighting circuit;
A deformation detector that detects deformation of the surface shape of the first and second electrodes;
A current modulation unit that modulates an alternating current controlled by the current control unit when the deformation of the surface shape is detected by the deformation detection unit;
Modulation enhancement that increases the modulation ratio at which the current modulation unit modulates the alternating current when the deformation detection unit detects the deformation of the surface shape while the alternating current is modulated by the current modulation unit and a part,
The current control unit repeatedly fluctuates up and down the anode duty ratio, which is the ratio of the anode period during which the first and second electrodes operate as anodes, and in synchronization with the up and down switching of the anode duty ratio, A projector that controls an alternating current supplied from the lighting circuit by expanding and contracting a polarity switching cycle for alternately switching the polarity of the alternating current . A driving method for driving a discharge lamp that emits light by arc discharge generated between first and second electrodes,
When supplying alternating current to the first and second electrodes, the anode duty ratio, which is the ratio of the anode period in which the first and second electrodes operate as anodes, is repeatedly varied up and down, and the anode Controlling the alternating current by expanding and contracting the polarity switching cycle for alternately switching the polarity of the alternating current in synchronization with the switching of the duty ratio up and down,
Detecting deformation of the surface shape of the first and second electrodes;
When the deformation of the surface shape is detected, the alternating current supplied to the first and second electrodes is modulated,
A driving method of increasing a modulation ratio for modulating the alternating current when the deformation of the surface shape is detected while the alternating current is modulated.

Images