JP2011126394A - Discharge lamp device - Google Patents

Abstract

Disclosed is a discharge lamp device capable of extending the life of a discharge lamp by delaying the occurrence of flicker.
A discharge lamp 1 in which a cathode 13 and an anode 12 are opposed to each other in an arc tube 11 and an emitter material is contained in the cathode 13, a power source 2 for lighting the discharge lamp 1, and a power source 2 are controlled. In the discharge lamp device having the control mechanism 3, the control mechanism 3 stops supplying the current to the lit discharge lamp 1 for a predetermined time, turns off the discharge lamp 1, and after the predetermined time has elapsed, The discharge lamp device is characterized by comprising an extinguishing time control means 31 for starting the current supply again and lighting the discharge lamp 1 again.
[Selection] Figure 1

Description

  The present invention relates to a discharge lamp device, in particular, a micro device mirror, a projection device (projector) for projecting an image by using light on a liquid crystal or a film, a semiconductor exposure device, a liquid crystal panel inspection device, The present invention relates to a discharge lamp apparatus used in technical fields such as stage lighting and searchlight.

  The discharge lamp apparatus used in the above technical field uses, as a light source, a discharge lamp in which a cathode and an anode are disposed opposite to each other in an arc tube, and an emitter material is contained in the cathode. The discharge lamp has a control mechanism. The lighting is controlled by.

  Further, the discharge lamp device used in the above technical field is normally used by continuously lighting the discharge lamp when necessary, and is not basically turned off particularly in a projector used for monitoring purposes. On the other hand, the discharge lamp may be turned off intentionally, but normally the projection device turns off the discharge lamp when it is no longer necessary to project an image (for example, at the end of a screening time in a movie theater). The lights are turned off until the next video is projected (when the next day at the movie theater starts). Also, in a discharge lamp device incorporated in a liquid crystal panel inspection device, stage lighting, and searchlight, the discharge lamp is turned on only when necessary, and the discharge lamp is turned off during an unnecessary time zone.

  As a discharge lamp used in these discharge lamp devices, a short arc type discharge lamp using doped tungsten whose emitter material is contained in the cathode is used, but the cathode emitter material is depleted during lighting. In addition, due to wear of the electrode or the like, a so-called flicker phenomenon occurs in which the arc suddenly starts to flicker after a certain lighting period and the irradiated surface flickers.

  When these discharge lamps are used as, for example, a light source of a projection apparatus, if a flicker phenomenon occurs during use, there is a problem that the image flickers and the image becomes difficult to see. In addition, when these discharge lamps are used as a light source of a liquid crystal panel inspection device, for example, when a flicker phenomenon occurs during use, flickering occurs in the light that is transmitted through the liquid crystal and projected onto the inspection screen, There has been a problem that it becomes impossible to properly determine which part of the liquid crystal has failed.

  This flicker level can be defined by the voltage swing width. However, in the cited reference 1, even if the voltage swing does not swing at the time of lighting at the rated current, it will start to swing when the lamp current is reduced. Is disclosed. Hereinafter, the current at which the voltage starts to swing is referred to as the arc stable minimum current. It is disclosed that the arc stable minimum current increases with the lighting time and can be recognized as flicker when the rated current is exceeded. In Cited Document 1, the life of the discharge lamp is predicted by the arc stable minimum current.

  On the other hand, in recent years, there has been a demand for a discharge lamp with a longer life, but research on the constituent parts of the lamp has reached a sufficiently high level, and it is difficult to extend the life by changing the constituent parts. It has become.

Japanese Patent No. 40000897

  An object of the present invention is to provide a discharge lamp device capable of extending the life of a discharge lamp by delaying the generation time of flicker in view of the above-mentioned problems of the prior art.

In order to solve the above-mentioned problems, a first aspect of the present invention is a discharge lamp in which a cathode and an anode are disposed opposite to each other in an arc tube, and an emitter substance is contained in the cathode, and the discharge lamp is lit. In a discharge lamp device having a power source and a control mechanism for controlling the power source, the control mechanism stops supplying current to the lit discharge lamp, turns off the discharge lamp, and a predetermined time has elapsed. After that, the discharge lamp device is characterized by further comprising an extinguishing time control means for starting current supply again and lighting the discharge lamp.
According to a second aspect of the present invention, there is provided a discharge lamp in which a cathode and an anode are disposed facing each other in an arc tube, and an emitter substance is contained in the cathode, a power source for lighting the discharge lamp, and a control for controlling the power source In the discharge lamp device having a mechanism, the control mechanism stops supplying current to the lit discharge lamp, turns off the discharge lamp, and when the cathode temperature becomes a predetermined temperature or lower, The discharge lamp device further comprises a light-off time control means for starting current supply and turning on the discharge lamp.
The invention according to claim 3 is characterized in that the extinguishing time control means does not stop supplying current to the lit discharge lamp, and does not supply the current to the lit discharge lamp. 3. The discharge lamp device according to claim 1, wherein the current supply is stopped after the current value supplied to the discharge lamp is gradually lowered.

According to the first aspect of the present invention, the arc stable minimum current can be reduced, and as a result, the life of the discharge lamp can be extended.
According to the second aspect of the present invention, the arc stable minimum current can be reduced. As a result, the life of the discharge lamp can be extended, and the turn-off time (OFF time) after the supply of current to the discharge lamp is stopped is easy. Can be set to
According to the third aspect of the present invention, the turn-off time (OFF time) after stopping the current supply to the discharge lamp can be set short, and the influence on the non-projection state of the discharge lamp can be reduced.

It is a figure which shows the structure of the discharge lamp apparatus which concerns on 1st Embodiment. It is the figure which showed the change of the lamp current of a discharge lamp, a lamp voltage, and a cathode tip temperature at the time of controlling the current supply to a discharge lamp, or a current non-supply by a light extinction time control means. It is a figure which shows the time change of the arc stable minimum electric current of a discharge lamp when the discharge lamp which is lighting is lighted again after extinguishing for a predetermined time. It is a table | surface which shows the time change of the arc stable minimum electric current of a discharge lamp when the discharge lamp which is lighting is lighted again after extinguishing for a predetermined time. It is a figure which shows the combined state of the tungsten crystal grain in the cathode front-end | tip part of a discharge lamp. It is a table | surface which shows the experimental result for determining light extinction time (OFF time). It is a figure which shows the structure of the discharge lamp apparatus which concerns on 2nd Embodiment.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a diagram showing a configuration of a discharge lamp device according to the present embodiment.
As shown in the figure, the discharge lamp 1 includes an arc tube 11 and a sealing portion 14 continuous at both ends thereof, and an anode 12 and a cathode 13 are disposed inside the arc tube 11 so as to face each other. , Respectively, are held by the sealing portion 14. Inside the sealing portion 14 is connected to the external lead rod 15 through a metal foil (not shown) or through a seal portion (rod seal) in which a glass member is directly welded to a lead extending from the electrode. It is connected to the. In the arc tube 11, mercury is enclosed as a luminescent substance, and at least one of xenon, argon, and krypton is enclosed as a buffer gas. The discharge lamp of this embodiment is a short arc mercury lamp. Alternatively, there is an arc tube 11 in which at least one of xenon, argon, and krypton is sealed as a luminescent substance, and such a discharge lamp is a short arc noble gas lamp.

  When electric power is supplied from the power source 2, the discharge lamp 1 emits light by arc discharge between the anode 12 and the cathode 13. The discharge lamp 1 is shown with the anode 12 up and the cathode 13 down. However, the vertical relationship is arbitrarily determined by the lamp design, and the tube axis of the arc tube 11, that is, the anode 12 and The virtual center axis formed in the direction in which the cathode 13 extends can be vertical or horizontal with respect to the ground. The cathode 13 uses emitter-doped tungsten containing trim or lanthanum or other rare earth metal or a compound thereof as an emitter material.

  As shown in the figure, a power source 2 for lighting the discharge lamp 1 is connected to the external lead rod 15 of the discharge lamp 1, and a control mechanism 3 is connected to the power source 2. The control mechanism 3 includes a turn-off time control unit 31. The extinguishing time control means 31 controls to turn off the discharge lamp 1 for a predetermined time by stopping the supply of current to the discharge lamp 1 that is lit, and to turn on the discharge lamp 1 again after the predetermined time has elapsed. It has the function to do.

  The turn-off time control means 31 controls current supply or current non-supply to the discharge lamp 1. When the turn-off time control means 31 receives the control signal S 1, the turn-off time control means 31 supplies the power supply 2 to the discharge lamp 1. After the current supply is stopped, and after a predetermined time, the control mechanism 3 controls the open voltage, breakdown voltage (ignition voltage) and inrush current (when the electrode is hot, the inrush current may be unnecessary or less) The current supply to the discharge lamp 1 is restored.

FIG. 2 is a diagram showing changes in the current, voltage, and cathode tip temperature of the discharge lamp 1 when the supply or non-supply of current to the discharge lamp 1 is controlled by the turn-off time control means 31.
As shown in the figure, at time T1, the control signal S1 is generated, the extinguishing time control means 31 is started, and at time T1, the current supply to the discharge lamp 1 is stopped, the voltage drops, and the temperature at the cathode tip Decreases, that is, the discharge lamp 1 is turned off.

  When the control signal S1 is received, the extinguishing time control means 31 applies an open voltage between the electrodes 12 and 13 at a time T2 after a predetermined time has elapsed, and further applies a breakdown voltage, so that the discharge lamp 1 is turned on again. Light up.

Next, the reason why the life of the discharge lamp can be extended by turning on the discharge lamp that has been turned on for a predetermined time and then turning on again will be described with reference to Table 1 in FIGS.
Table 1 in FIGS. 3 and 4 is a diagram showing a temporal change in the arc stable minimum current of the discharge lamp when a lighting discharge lamp is turned off for a predetermined time and then turned on again for a certain discharge lamp. . The rated current of the discharge lamp used here is 80A.

  As shown in Table 1 of FIG. 4, the arc stable minimum current was measured by supplying a current lower than the rated current of 80 A every 24 hours after the lighting time of 100 hours had elapsed. From the change of the arc stable minimum current until the lighting time of 220 hours elapses, the time when the arc stable minimum current is 80 A was predicted. That is, when the arc stable minimum current is 80 A, it becomes the same as the rated current of 80 A, which means that flicker occurs even if the lamp is turned on at the rated current of 80 A.

  As shown in FIG. 3, the minimum arc stable minimum current is predicted to be the same as the rated current 80A. As shown in FIG. 3, the transition of the minimum arc stable current from the lighting time of 100 hours to the lighting time of 220 hours is minimized. It is obtained from the prediction line A obtained by the square method. In other words, assuming that the predicted time point B at which the predicted line A intersects the arc stable minimum current 80A is the predicted life, the life time of the discharge lamp is 246 hours.

  In this experiment, as shown in Table 1 of FIG. 3 and FIG. 4, the arc stable minimum current was measured after 220 hours of lighting of the discharge lamp, and then turned off. The turn-off time was 1 minute, and then the lamp was turned on again. The arc stable minimum current was measured after the lighting time of 222 hours was 53 A. Also, at the time of 244 hours in the vicinity of the previously predicted life, the arc stable minimum current is 57A, and in the initial life prediction, the arc stable minimum current should be the end of life when flicker occurs at 80A. However, it can be seen that the arc stable minimum current is lower than 80 A, flicker does not occur, and the discharge lamp continues to be usable.

  Thereafter, when this discharge lamp was turned on until 340 hours, the arc stable minimum current exceeded 80 A, and flicker was generated. The turn-off time was 1 minute, and then the light was turned on again. When the arc stable minimum current was measured at 342 hours, the value was 60 A, which was lower than 80 A. That is, it can be seen that even when the discharge lamp is lit at the rated current of 80 A, flicker does not occur and the life is further extended. When the discharge lamp was turned on again, the arc stable minimum current became 81 A in 460 hours, and flicker was generated.

  Thus, in this discharge lamp, when it is continuously lit, flicker occurs in 246 hours and the lamp has reached the end of its life. After a lapse of 1 minute, the current supply is started again to turn on the discharge lamp. After a few hours, the current supply is stopped and the discharge lamp is turned off for the lit discharge lamp. When the current supply is started again and the discharge lamp is turned on after the turn-off time has elapsed, the flicker generation time can be extended to 460 hours, and the flicker generation time can be greatly delayed. The lamp life could be extended significantly.

Next, the reason why the life is extended when the discharge lamp that is continuously lit is extinguished at a predetermined time for a predetermined time will be described with reference to FIG.
FIG. 5 shows a bond diagram of tungsten crystal grains at the cathode tip of the discharge lamp. As shown in the figure, black lines at the boundaries between crystal grains indicate grain boundaries. The emitter material passes through this grain boundary and is supplied to the cathode tip. That is, the larger the number of grain boundaries, the higher the emitter supply capability. FIG. 5A is a bond diagram of crystal grains in the initial stage of lighting. In this case, since the number of grain boundaries is large, the supply power of the emitter is high. Therefore, in this case, the flicker phenomenon cannot be recognized. On the other hand, FIG. 5B shows the state of crystal grains when the lamp is continuously lit for a long time. In this case, it can be seen that the crystal grains are integrated and enlarged, and the number of grain boundaries is reduced as compared with FIG. In this state, it is difficult to supply the emitter substance to the tip of the cathode through the grain boundary, and it is considered that the flicker phenomenon occurs.

  In other words, when the current supply is stopped and the lamp is turned off during continuous lighting, the temperature of the cathode decreases and the cathode cools down, the crystal grains at the tip of the cathode crack and new grain boundaries are generated, and the discharge lamp again. When the is turned on, the emitter material is supplied to the cathode tip through the generated grain boundary, so it is considered that the emitter supply capability is suppressed and the flicker generation time is delayed to extend the life of the discharge lamp. It is done.

Next, an experiment for determining the turn-off time (OFF time) will be described with reference to Table 2 in FIG.
For the experiment, three types of discharge lamps (A, B, C) filled with xenon were prepared. The specification of each discharge lamp, the minimum OFF time until the arc stable minimum current decreased in various current waveforms, and the cathode The trunk temperature was measured. Here, the current waveform includes Type 1 (a control method in which the current is reduced from the steady current to 0 A at once, and after the minimum OFF time has elapsed, the steady current is restored again) and Type 2 (gradually from the steady current, for example, 10 A / sec. The current was reduced until the arc discharge could not be maintained at a rate, the light was extinguished, and after the minimum OFF time had elapsed, the control method was changed to a steady current again.

  First, each discharge lamp is lit until a time when an increase in the arc stable minimum current can be confirmed. At that time, a predetermined OFF time (for example, starting from 0.1 sec) is inserted, and the arc stable minimum current is confirmed. At this time, if the arc stable minimum current does not change before and after insertion of the OFF time (the arc stable minimum current decreases), the predetermined OFF time (adds 0.1 sec to the previous OFF time or the OFF time until the previous time again. If it is longer than 1 sec, add 1 sec) and check the minimum arc stable current. This operation is repeated until the arc stable minimum current decreases, and the OFF time when the arc stable minimum current decreases is defined as the minimum OFF time.

  The measured value of the minimum OFF time is 3 to 5 times for each discharge lamp (after the first measurement, the lamp is lit until an increase in the arc stable minimum current is confirmed again, and the second measurement and lighting are performed. , Arc stable minimum current rise, repeat measurement) and recorded the width of the result.

  In order to light the discharge lamp with the rated power after the end of the OFF time, it is considered that the cathode tip temperature needs to be lower than a certain temperature. However, when the current supply is stopped, the temperature of the electrode of the discharge lamp decreases and contracts. Therefore, the position of the cathode tip changes rapidly after the supply of current is stopped. It is difficult to. Therefore, here, the temperature of the cathode electrode body portion, which is easy to measure, is measured and used as an indicator of the cathode tip temperature.

  For example, in the case of a current waveform of Type 1 in the discharge lamp A, it is understood that the OFF time is 6 seconds or more. If the discharge lamp A has a Type 1 current waveform and the OFF time is 3 seconds or more and less than 6 seconds, the arc stable minimum current may not drop even if the discharge lamp A is turned off, and the life cannot be extended. There is. Further, it can be seen that the OFF time is required to be 0.3 sec or longer in the case of the current waveform of Type 2 in the lamp B, for example. In the case of a current waveform of type 2 in lamp B, if the OFF time is 0.1 sec or more and less than 0.3 sec, the arc stable minimum current may not drop even if the discharge lamp B is turned off, thus extending the life. May not be possible. Further, for example, in the case of a current waveform of Type 1 in the discharge lamp C, the OFF time is set so that the current injection is resumed at a cathode body temperature of 1520K or less. This is the case of a current waveform of Type 1 in the discharge lamp C. If the OFF time is 5 seconds or more, the extinguishing time becomes longer, the temperature of the cathode decreases accordingly, and the cathode body temperature 1520K or less is OFF. This means that 5 seconds or more are required.

  As a method of stopping the current to the discharge lamp, the OFF time can be shortened by gradually decreasing the current supply as in the current waveform of Type2. This is because when the current supply is gradually lowered, the light output of the discharge lamp becomes weak at the beginning of the decrease in the current value, but the light of the discharge lamp can be used. On the other hand, in the range where the current supply is gradually lowered, the cathode temperature is lower than that at the rated current, so after the current supply is completely stopped (after the current value becomes 0), the cathode temperature becomes the predetermined temperature (the crystal grains are This is thought to be because the time required for the temperature to fall to (the cracking temperature) is shortened. As a result, by gradually decreasing the current as in the current waveform of Type 2, the light output of the discharge lamp becomes weak at the beginning of the decrease in the current value, but the light of the discharge lamp can be used. In addition, since the turn-off time during which the discharge lamp is completely turned off can be shortened, the influence of the non-projection state due to the turn-off of the discharge lamp can be reduced.

A second embodiment of the present invention will be described with reference to FIG.
FIG. 7 is a diagram showing a configuration of the discharge lamp device according to the present embodiment.
As described above, the extinguishing time (OFF time) may be determined by measuring the temperature of the cathode. In this method, as shown in FIG. 7, the temperature of the body of the cathode is measured by the radiation thermometer 4, and the measured temperature is sent to the turn-off time control means 31 as a signal S2. As a result, the temperature of the cooling cathode 13 is measured with the radiation thermometer 4, and when the temperature of the cathode 13 falls below a predetermined temperature, cracks of the crystal grains at the tip of the cathode 13 are surely generated, and the grain boundary is reliably formed. At that time, when the discharge lamp 1 is turned on again, the emitter material passes through the broken grain boundary and is supplied to the tip of the cathode 13, thereby suppressing a decrease in the supply capability of the emitter, The life of the discharge lamp 1 can be extended by delaying the occurrence of flicker. Note that the configuration of other reference numerals shown in FIG. 7 corresponds to the configuration of the same reference numerals shown in FIG.

DESCRIPTION OF SYMBOLS 1 Discharge lamp 11 Arc tube 12 Anode 13 Cathode 14 Sealing part 15 External lead rod 2 Power supply 3 Control mechanism 31 Light-off time control means 4 Radiation thermometer

Claims (3)

In a discharge lamp having a discharge lamp in which a cathode and an anode are disposed opposite to each other in an arc tube and an emitter material is contained in the cathode, a power source for lighting the discharge lamp, and a control mechanism for controlling the power source,
The control mechanism stops the current supply to the discharge lamp that is lit, turns off the discharge lamp, and after a predetermined time has passed, starts the current supply again and turns off the discharge lamp. A discharge lamp device comprising a time control means. In a discharge lamp having a discharge lamp in which a cathode and an anode are disposed opposite to each other in an arc tube and an emitter material is contained in the cathode, a power source for lighting the discharge lamp, and a control mechanism for controlling the power source,
The control mechanism stops supplying the current to the lit discharge lamp, turns off the discharge lamp, and starts supplying the current again when the cathode temperature falls below a predetermined temperature. A discharge lamp device comprising a turn-off time control means for turning on the discharge lamp. The extinguishing time control means replaces the current supply to the lit discharge lamp with a current value supplied to the discharge lamp with respect to the lit discharge lamp. The discharge lamp device according to claim 1, wherein the current supply is stopped after the voltage is gradually lowered.