CN101399149A - Discharge lamp device - Google Patents

Abstract

The present invention provides an electric discharge lamp device which is sufficiently actualized with the countermeasure which is used for preventing the high temperature generated by the large ouput of electric discharge lamp and is sufficiently actualized with the countermeasure that is used for preventing the electrode loss. The electric discharge lamp device according to the invention is characterized by comprising the following components: the electric discharge lamp (10) which is relatively configured with a pair of electrodes (2, 3) in the luminous tube, and a measuring unit (30) which monitors the lighting state of electric discharge lamp (10). The measuring unit (30) monitors the light radiation generated by the heat transmission object (M) from the inner part caused by the attrition or dilapidation of electrode along with the lighing of electric disharge lamp (10).

Description

discharge lamp device

technical field

The invention relates to a discharge lamp arrangement. In particular, it relates to a discharge lamp device for a short-arc discharge lamp used in an exposure device for a liquid crystal or a semiconductor wafer.

Background technique

Discharge lamps can be classified into several lamps from the viewpoint of luminescent substance, distance between electrodes, and pressure inside the luminous tube. Among them, in terms of luminescent substance, it can be classified into xenon lamp with xenon gas as luminescent substance, mercury lamp with mercury as luminescent substance, and Metal halide lamps in which rare earth metals other than mercury are used as luminescent substances, etc. In addition, from the viewpoint of the distance between electrodes, they can be classified into short-arc type discharge lamps with short inter-electrode distances and long-arc type discharge lamps with long inter-electrode distances. Furthermore, from the viewpoint of the vapor pressure in the arc tube, they can be classified into low-pressure discharge lamps, high-pressure discharge lamps, and ultra-high-pressure discharge lamps.

Among them, for short-arc high-pressure mercury lamps, quartz glass with a high heat-resistant temperature is used as the luminous tube, and tungsten electrodes are arranged inside the luminous tube with a gap of about 2 to 12 mm, and then sealed as a luminous substance inside the luminous tube. Mercury, argon and other rare gases with a vapor pressure of 10 ⁵ Pa to 10 ⁷ Pa when bright.

This short-arc high-pressure mercury lamp has the advantage of obtaining high luminance due to a short distance between electrodes, and thus has been widely used as a light source for exposure in lithography.

On the other hand, in recent years, not only semiconductor wafers, but also a light source for exposure of liquid crystal substrates used in liquid crystal substrates, especially large-area liquid crystal displays, has attracted attention. From the viewpoint of improving throughput in the manufacturing process, There is also a strong demand for increasing the output of lamps as light sources.

When the rated power consumption changes due to the increase in output of the discharge lamp, the value of the current flowing through the discharge lamp generally increases although it depends on the design value of the current and voltage.

Therefore, there arises a problem that the electrodes (in particular, the anode that is lit by direct current) receive a large amount of electron collisions, and the temperature rises and melts easily. In addition to the anode, in a discharge lamp arranged vertically, the upper electrode is susceptible to heat from the arc due to thermal convection in the arc tube, and similarly heats up and melts.

In addition, if the electrodes, especially their tip parts, melt, not only the arc becomes unstable, but also the material constituting the electrodes evaporates and adheres to the inner surface of the arc tube, resulting in a decrease in radiation output.

This phenomenon is not limited to short-arc high-pressure mercury lamps, but is a common problem when increasing the output of discharge lamps. Conventionally, there have been proposed structures or methods in which an air cooling mechanism is provided outside the discharge lamp to force air cooling. In addition, A so-called water-cooled discharge lamp has been proposed in which a cooling water flow path is provided inside the electrodes to allow the cooling water to flow inside the electrodes in a discharge lamp having a higher output (for example, Japanese Patent No. 3075094).

Furthermore, a structure has been proposed in which a heat transfer material such as silver or copper is enclosed in a closed space provided with a cavity inside the electrode (Japanese Patent Laid-Open No. 2004-6246). The heat transfer body is made of a metal with a lower melting point than the metal constituting the electrode body. When the lamp is turned on, the heat from the tip of the electrode is efficiently transferred to the rear by utilizing the convection and boiling transfer functions of the heat transfer body in a liquid state.

However, the electrode having the above structure can solve the problem of electrode wear compared with conventional electrodes, but the electrode wear is not completely suppressed. When the electrode is worn out, the discharge is significantly unstable due to the shape of the wear, and in the worst case, a hole is formed in the electrode main body to cause a problem that the heat transfer body leaks out. In addition, there is a possibility that the electrode body may be damaged due to cracks or the like caused by the electrode body raw material, and the heat transfer body may leak out.

Patent Document 1: Japanese Patent Laid-Open No. 2004-6246

Contents of the invention

The problem to be solved by the present invention is to provide a discharge lamp device in view of the above-mentioned problems, which sufficiently implements countermeasures against the increase in temperature accompanying the increase in the output of the discharge lamp, and which is also sufficiently equipped to cope with the wear of the electrodes, and the electrode main body. Countermeasures in case of damage due to raw materials.

In order to solve the above-mentioned problems, the discharge lamp device of the present invention is characterized in that it includes: a discharge lamp in which a pair of electrodes are arranged facing each other inside the arc tube; and a measuring unit for monitoring the lighting state of the discharge lamp; An electrode is composed of an electrode main body having a closed space formed therein, and a metal having a melting point lower than that of a metal constituting the electrode main body enclosed in the closed space, and the measurement unit is accompanied by the heat transfer body Light emission caused by the metal constituting the heat transfer body generated when the discharge lamp is turned on to leak from the electrode main body is detected.

Furthermore, the measurement means detects a change in ratio between light emission caused by the metal constituting the heat transfer body and light of a wavelength not emitted by the metal constituting the heat transfer body.

Furthermore, it is characterized in that the electrode main body is made of a metal mainly composed of tungsten.

Furthermore, it is characterized in that the said heat transfer body contains any metal of gold, silver, and copper.

According to the above structure, the discharge lamp device of the present invention can detect the discharge lamp device by detecting the light emission of the metal constituting the heat transfer body by the measuring unit even when the heat transfer body inside the electrode is leaked due to wear or damage of the electrode. In case of abnormality, stop the discharge lamp from lighting to prevent continuous lighting under abnormal conditions.

Description of drawings

Fig. 1 shows an overall configuration diagram of a discharge lamp device of the present invention.

Fig. 2 shows an overall view of the discharge lamp of the present invention.

Figure 3 shows the electrodes of the discharge lamp of the present invention.

Fig. 4 shows changes in illuminance of a discharge lamp.

Fig. 5 shows changes in illuminance of the discharge lamp.

Fig. 6 shows a flowchart for detecting changes in illuminance by the present invention.

Detailed ways

Fig. 1 is a schematic diagram showing the overall structure of a discharge lamp device of the present invention. The discharge lamp device of the present invention is essentially composed of a discharge lamp 10 and a measuring unit 30 for detecting radiated light from the discharge lamp, and further includes a power supply device 40 for controlling lighting of the discharge lamp 10 . The power supply device 40 is a device that supplies current to the discharge lamp 10, and also has a mechanism that detects the lighting state of the discharge lamp 10, for example, lighting power, and performs feedback control. A concave reflector 50 is attached to the discharge lamp 10 .

FIG. 2 shows an enlarged view of the discharge lamp 10 . The luminous tube of the discharge lamp 10 is made of quartz glass, and the both ends of the substantially spherical luminous part 11 are integrally connected and provided with the sealing part 12. An anode 2 and a cathode 3 are arranged opposite to each other in the light-emitting part 11, and each electrode (2, 3) is respectively held by the sealing part 12, and is connected to an external lead bar 13 through a metal foil not shown in the figure, and is connected to the power supply in Fig. 1 device 40.

In addition, predetermined amounts of luminescent substances such as mercury, xenon, and argon, and a starting gas are sealed in the light emitting unit 11 . In addition, the discharge lamp emits light by arc discharge from the anode 2 and the cathode 3 when electric power is supplied from the power supply device 40 . In addition, this discharge lamp is a so-called vertical lighting type discharge lamp, with the anode 2 on the top and the cathode 3 on the bottom, and the tube axis of the light emitting part 11 is supported in a direction substantially perpendicular to the ground to be lit.

FIG. 3 shows a cross-sectional structure of the anode 2 . The anode 2 has an electrode main body 20 and a heat transfer body M inside it. The electrode main body 20 is made of a refractory metal or an alloy mainly composed of a refractory metal, and has a container shape in which a closed space S (hereinafter also referred to as “inner space”) is formed therein. The heat transfer body M is a metal hermetically sealed inside the electrode main body 20 , and is made of a metal having a lower melting point than the metal constituting the electrode main body 20 .

The electrode main body 20 is composed of a rear end portion 201 joined to a shaft portion 21 , a trunk portion 202 , and a front end portion 203 , and the rear end portion 201 is formed with an insertion hole 2011 for the shaft portion 21 . The adhesive 22 is used to fix the shaft portion 21 and the rear end portion 201 .

As the metal constituting the electrode main body 20, a refractory metal having a melting point of 3000 (K) or higher such as tungsten, rhenium, or tantalum is used. In particular, tungsten is preferable because it does not easily react with the internal heat transfer body M, and so-called pure tungsten with a purity of 99.9% or more is more preferable.

In addition, as an alloy mainly composed of a refractory metal, for example, a tungsten-rhenium alloy mainly composed of tungsten can be used. High resistance to repeated stress at high temperature, enabling long electrode life.

The heat transfer body M is made of a metal having a lower melting point than the metal constituting the electrode main body 20 . Specifically, when tungsten is used as the constituent material of the electrode main body 20, gold, silver, copper, or an alloy mainly composed of these can be used as the heat transfer body M. The gold, silver, and copper mentioned above are not alloyed with tungsten, so they are also preferable metals in terms of functioning as a heat transfer body. Among them, since gold is expensive, silver and copper are preferable materials for practical use.

In addition, as another specific example, when rhenium is used as the metal constituting the electrode main body 20 , tungsten can be used as the heat transfer body M.

The advantage of using rhenium as the metal constituting the electrode main body 20 is that, in the case of mercury lamps or metal halide lamps in which halogen is enclosed, corrosion of the electrodes can be prevented, thereby prolonging the life of the discharge lamp.

The electrode main body 20 has a substantially container-shaped structure having a closed space S inside. Therefore, even if the heat transfer body M is heated and melted, and a part thereof is vaporized, it does not leak into the light-emitting space of the light-emitting part 11 .

Therefore, unlike the water-cooled discharge lamp, the discharge lamp of the present invention requires a mechanism for supplying and discharging the cooling medium from the outside, and not only can maintain the cooling mechanism with a very simple structure, but also can achieve the function of the discharge lamp once the discharge lamp is manufactured. There is no need to replenish the heat transfer body until the end of life, and the cooling mechanism can continue to function.

That is, whereas conventionally proposed high-output discharge lamps rely on a cooling mechanism outside the discharge lamp, the discharge lamp of the present invention is very different in that the lamp itself has a cooling function with a very simple structure.

The measurement unit 30 analyzes the emitted light of the discharge lamp 10 by an input lens 31 installed near the opening of the concave reflector, a transmission line 32 such as an optical fiber that transmits light incident on the input lens 31, and a terminal of the transmission line 32. The radiation detection mechanism 33 and the signal processing mechanism 34 are constituted.

The input lens 31 receives the radiated light of the discharge lamp 10 and is preferably arranged at a position where it can receive direct light, but is provided at a position where it does not interfere with the original purpose of use of the discharge lamp 10 . Specifically, near the opening of the concave reflector 30 as shown in the figure, it may be a mirror or a side of a lens disposed on the neck opening side of the concave reflector 30 or in front of the opening side. The radiated light detection mechanism 33 is composed of the following parts: a wavelength selective filter for passing only predetermined light in the radiated light of the discharge lamp 1; a dimming filter for passing predetermined light through the wavelength selective filter adjusted to an intensity suitable for processing; and a light conversion element that receives the predetermined light and converts it into an electrical signal. For example, a bandpass filter or a colored glass filter is used as the wavelength selection filter, an ND filter is used as the light reduction filter, and a silicon photodiode is used as the light conversion element.

The transmission line 32 uses an optical fiber or the like, and plays a role of transmitting the light of a predetermined wavelength received by the input lens 31 to the radiation detection mechanism 33 .

The radiation detection mechanism 33 includes a sensor that receives light of a predetermined wavelength guided by the transmission line 32, and plays a role of converting the amount of light received by the sensor into an appropriate electrical signal. The signal processing unit 34 is a unit that compares the electrical signal received by the radiation detection unit 33 with a reference level, and displays an abnormal state when the guided electrical signal exceeds the reference level. In addition, the input lens 31 and the transmission line 32 are not indispensable components, and the light may be directly received by the transmission line 32, or the radiation detection mechanism 33 may be arranged at a position to directly receive radiation from the lamp, and the input lens 31 may be omitted. , Transmission line 32 .

The light of a predetermined wavelength to be detected by the radiation detection means 33 must be light of a wavelength at which the metal constituting the heat transfer body enclosed in the closed space of the electrode main body emits light. For example, when gold is used as the heat transfer body, the light detected by the radiation detection mechanism 33 is light with a wavelength of 460nm, a wavelength of 479nm, and a wavelength of 751nm; Light, when copper is used as the heat transfer body, is light with a wavelength of 325nm, a wavelength of 465nm, a wavelength of 511nm, and a wavelength of 522nm.

In addition, the measurement unit 30 may detect not only the light of the wavelength emitted by the metal constituting the heat transfer body, but also the light of the wavelength not generated by the metal constituting the heat transfer body. The wavelength is, for example, light with a wavelength of 500 nm, light with a wavelength of 520 nm, light with a wavelength of 600 nm, and light with a wavelength of 650 nm when gold is enclosed as a heat transfer body, and light with a wavelength of 460 nm or light with a wavelength of 600 nm when silver is enclosed as a heat transfer body. , Light with a wavelength of 650nm, when copper is enclosed as a heat transfer body, it is light with a wavelength of 600nm, light with a wavelength of 650nm, and light with a wavelength of 490nm. The light intensity ratio of the luminescence caused by the metal to the light of the wavelength not affected by the metal constituting the heat transfer body contributes to the detection of an abnormal state from the change in the irradiation ratio.

Here, the phenomenon of unstable discharge due to wear of the anode 2 of the discharge lamp 10, the phenomenon of breakage caused by the electrode body material, and the phenomenon of the heat transfer body leaking from the inner space of the electrode body will be described. Although the anode is made of a high-melting-point metal such as tungsten, the material constituting the anode evaporates and is lost as the lighting time elapses. In particular, when the arc locally concentrates on a part of the surface of the anode, etc., the wear at this part becomes severe, and eventually the electrode main body is broken. In addition, when there are cracks, voids, etc. in the electrode main body, the local strength will decrease, so there is a possibility of damage. In any case, a path through which the sealed heat transfer body leaks into the discharge space is formed, so that the heat transfer body in a liquid or gaseous state leaks out.

FIG. 4 shows changes in illuminance of the discharge lamp when the discharge lamp 10 falls into an abnormal lighting state. That is, it is a diagram for explaining how the discharge lamp device of the present invention detects an abnormal lighting state. In the figure, the vertical axis represents the illuminance at which the sensor detects light with a wavelength of 521 nm, that is, the radiation illuminance, and the horizontal axis represents the elapsed lighting time (minutes). The irradiance represents a relative value based on the illuminance at a wavelength of 521 nm observed in a stable lighting state. Specifically, to turn on the discharge lamp 10 , for example, an illuminance value in a stable lighting state after 60 minutes can be selected. In addition, the example in FIG. 4 is an example in which the discharge lamp 10 has the structure shown in FIG. 2 , mercury and xenon are sealed in the light emitting part 11 as a light emitting material, and silver is sealed in the electrode main body 20 as a heat transfer body M.

In the figure, time -20 to time 0 is a time zone in which the discharge lamp 10 is stably lit. Then, at time 0, the silver sealed inside starts to leak from the electrode main body 20 into the light emitting space. At this moment, silver is newly mixed into the luminescent space in addition to mercury and xenon, which are the original luminescent substances, and light with a wavelength of 521 nm is strongly emitted as silver luminescence, resulting in a sharp increase in irradiance. In addition, the radiation illuminance at a wavelength of 521 nm rises sharply at time 0 and then gradually decreases. This is because silver, which constitutes the metal of the heat transfer body, adheres to the inner surface of the arc tube and attenuates the amount of light emitted to the outside of the lamp.

The emitted light detection means 33 determines that it is in an abnormal state when the relative value of the detected light exceeds a predetermined threshold value. The threshold value should be set higher than the normal stable state to a certain extent in consideration of fluctuations in the detected light even in the steady lighting state. In addition, when the above-mentioned abnormal state is detected, it is preferable to set a continuous detection time. Specifically, when the detected relative illuminance exceeds the threshold for at least a predetermined time (t1), it is identified as an abnormal lighting state. This is because an instantaneous illuminance change is regarded as an error.

In addition, it is preferable to set an upper limit value (t2) for the duration of the detected relative illuminance value exceeding the threshold value. At this time, even if the detected relative illuminance value exceeds the threshold value for a predetermined time (t1), it will not continue to exceed the threshold value until the upper limit time t2 (t2>t1) is exceeded. The relative illuminance value detected at the time (t2) is lower than the threshold value as the condition of abnormal lighting.

This is based on a reason specific to the discharge lamp of the present invention. That is, when a certain amount of time has elapsed since the metal constituting the heat transfer body has been mixed into the light-emitting space, the metal constituting the heat transfer body starts to adhere to the inner surface of the light-emitting tube. Therefore, although light with a wavelength of 521nm to be detected by the radiation detection means 33 is originally generated in the light emitting space, it is shielded by the metal formed by the heat transfer body attached to the inner surface and is not radiated to the outside of the lamp. As a result, the detected illuminance decreases.

Here, the lower limit value (t1) of the continuous detection time is not so much affected by the type of lamp, and may be set to, for example, 0.5 seconds to 10 seconds regardless of the type of lamp. However, the upper limit (t2) of the continuous detection time varies depending on the type of lamp or the use environment, such as the physical size of the light-emitting space, the amount of heat transfer material enclosed, the type of heat transfer material, and the temperature around the lamp. . To give an example, it is set to 15 minutes to 20 minutes from exceeding the threshold value. In FIG. 4 , the threshold value is 20, and the upper limit t2 is set to 20 minutes, for example. Therefore, it is preferable that the time when the relative illuminance value detected by the radiation detection means 33 exceeds the threshold value is not less than the lower limit value (t1) and does not exceed the upper limit value (t2).

In addition, when the detected relative illuminance value exceeds the upper limit (t2), it may be considered that the abnormal lighting is due to other reasons than the leakage of the heat transfer body. Therefore, when the detected relative illuminance value continues to exceed the threshold value during the upper limit time t2, abnormal lighting can be identified or speculated to be caused by other causes than the abnormal lighting considered to be a problem in the present invention, and countermeasures can be taken.

FIG. 5 also shows changes in illuminance of the discharge lamp, and shows a case based on a detection method different from that in FIG. 4 . Specifically, the detection method shown in FIG. 4 is a method of directly detecting the radiated light caused by the leakage of the metal constituting the heat transfer body. In contrast, the detection method shown in FIG. A method of detecting changes in the illuminance of emitted light and comparative light, and the ratio of the illuminance of the two lights. In the figure, the left vertical axis represents the irradiance of the radiated light caused by the leakage of the metal constituting the heat transfer body and the irradiance of the comparison light, the right vertical axis represents the ratio of the two relative irradiances, and the horizontal axis represents the elapsed lighting time (point). The irradiance represents a relative value based on the irradiance in a steady lighting state. The discharge lamp 10 has the structure shown in FIG. 2 , and mercury and xenon are sealed in the light emitting part 11 as light-emitting substances, and silver is sealed in the electrode main body 20 as the heat transfer body M as an example. The radiation light detection means sets light with a wavelength of 521 nm as detection of radiation light caused by leakage of the metal constituting the heat transfer body, and sets light with a wavelength of 420 nm as comparison light.

At time 0, time -20 to time 0 is a time zone in which the discharge lamp 10 is stably lit. Then, at time 0, a crack occurs in a part of the electrode body 20, and the silver sealed in the electrode body 20 starts to leak into the light emitting space. At this moment, silver is newly mixed into the luminescent space in addition to mercury and xenon, which are the original luminescent substances, and light with a wavelength of 521 nm is strongly emitted as silver luminescence, resulting in a sharp increase in irradiance.

As described above, the irradiance at a wavelength of 521 nm rises sharply at time 0 and then gradually decreases. On the other hand, the relative illuminance value of the 460 nm irradiance of the comparative light was 10 until time 0 (heat transfer body leakage start time), and gradually decreased when time 0 passed. The reason for the reduction in illuminance is the same as the reason for the reduction in the wavelength of 521 nm, and it is because silver adheres to the inner surface of the arc tube and the comparison light is also blocked. Therefore, in the case of this detection method, although the illuminance ratio rises sharply at time 0, it can maintain a substantially constant value thereafter, so that it is easy to detect an abnormal lighting state. In addition, the irradiance ratio gradually decreased after about 50 minutes had elapsed. This is because the heat transfer body M sealed in the electrode main body almost completely leaked out, and the emission amount of light with a wavelength of 521 nm itself decreased.

In this way, instead of directly detecting the change of the luminescence caused by the metal constituting the heat transfer body, the method of detecting and comparing the change of the illuminance ratio of the light can continue for a long time to show the state of the abnormal state, so the detection is easy to carry out, or can ensure The time during which the operator can make judgments. In addition, even when electromagnetic interference or the like is received from the outside, since both the signal system for detecting the light emission of the metal constituting the heat transfer body and the signal system for detecting the light emission of the comparative light are affected under the same conditions, the relationship between the two Scale can also be considered as a numerical value that is difficult to influence. Furthermore, when the lighting power of the lamp is increased or decreased, both the light emission of the metal constituting the heat transfer body and the light emission of the comparative light increase or decrease, so the ratio of the two can also be regarded as a numerical value that is not easily affected.

In addition, the wavelength that needs to be detected by the radiation detection means 33 is the radiation wavelength caused by the metal used as the heat transfer body. On the other hand, the conditions for the comparison light are not the emission wavelength of the metal constituting the heat transfer body, and the wavelength not affected by the reaction between the metal constituting the heat transfer body and the luminescent substance such as mercury or xenon. In addition, it is preferable that the emitted light detection means 33 detects the detection light using the relative value of the illuminance of the same wavelength as that in the steady lighting state. This is because light of a detection wavelength is emitted to some extent even in a stable lighting state. In the above-mentioned embodiment, the relative value is identified with the illuminance in the stable lighting state as a reference, and when the relative value is above the threshold value, it is identified as an abnormal state.

In addition, when detecting the above-mentioned abnormal state, setting the lower limit value (t1) of the continuous detection time is the same as the above-mentioned detection method of FIG. 4 . On the other hand, in this detection method, it is less necessary to set the upper limit value (t2) of the continuous detection time. This is because the illuminance ratio remains constant at a high ratio for a long time as shown in FIG. 5 . An example of keeping it constant in this way is the case where there are few fluctuations in the amount of leakage, but even when the amount of leakage fluctuates greatly, although the change in the light emission of the metal that constitutes the heat transfer body fluctuates, the ratio also fluctuates, but it is easy to take a long time. maintain a high level.

6 is the detection method shown in FIG. 5 , and is a flow chart showing a method of detecting the illuminance of radiated light and comparative light caused by leakage of metal constituting the heat transfer body to detect changes in the illuminance ratio of the two lights.

In step 1, the signal S1 and the signal S2 from the measurement unit 30 are input. The signal S1 is a signal of the relative irradiance value of the radiated light due to the leakage of the metal constituting the heat transfer body, and the signal S2 is a signal of the relative irradiance value of the comparison light. The above operations are performed by the signal processing unit 34 .

In step 2, the illuminance ratio signal S3 is formed from the signal S1 and the signal S2 (S1/S2). This operation is performed, for example, by the illuminance ratio generation unit of the signal processing unit 34 .

In step 3, the comparison between the illuminance proportional signal S3 and the threshold value is performed. Return to step 1 when the illuminance proportional signal S3 is lower than the threshold value. On the other hand, when the illuminance proportional signal S3 is higher than the threshold value, it proceeds to the next step. This operation is performed, for example, by the comparing means of the signal processing means 34 .

In step 4, an alarm is issued when the illuminance proportional signal S3 is higher than the threshold value. The alarm may be a sound, a visual representation method, or other methods such as vibration.

In step 5, the operator deactivates the alarm, or automatically deactivates it if it persists.

As described above, the discharge lamp device of the present invention includes a discharge lamp in which a pair of electrodes are disposed opposite to each other inside the luminous tube, and a measuring unit for monitoring the lighting state of the discharge lamp. At least one electrode of the above-mentioned discharge lamp is formed by There is an electrode main body with a closed space, and a metal having a melting point lower than that of a metal constituting the electrode main body enclosed in the closed space, and the above-mentioned measurement unit has a structure that, due to the above-mentioned electrode main body accompanying the discharge The light emission caused by the metal constituting the heat transfer body, which is generated when the heat transfer body leaks due to the lamp being turned on or damaged, is detected. With the above structure, even when the heat transfer body inside the electrode leaks, the measurement unit By detecting the light emission of the metal constituting the heat transfer body, it is also possible to detect an abnormality of the discharge lamp device, stop lighting of the discharge lamp, and prevent continuous lighting in an abnormal state.

Claims (4)

1. discharge lamp deivce comprises: disposes the discharge lamp of pair of electrodes in the inside of luminous tube relatively and monitors the measuring unit of the illuminating state of this discharge lamp, it is characterized in that,

At least one electrode of above-mentioned discharge lamp, be included in inside be formed with confined space electrode body, be enclosed in the thermal conductor of having in this confined space than the low-melting fusing point of the metal that constitutes this electrode body, and

The luminous detection that produces when above-mentioned measuring unit spills above-mentioned thermal conductor, cause by the metal that constitutes thermal conductor.

2. discharge lamp deivce as claimed in claim 1 is characterized in that,

Above-mentioned measuring unit detects by cause luminous of the metal that constitutes thermal conductor and can not detect the variation of its ratio by the light of the luminous wavelength of the metal that constitutes this thermal conductor.

3. discharge lamp deivce as claimed in claim 1 or 2 is characterized in that,

Above-mentioned electrode body is made of the metal that with tungsten is principal component.

4. discharge lamp deivce as claimed in claim 1 or 2 is characterized in that,

Above-mentioned thermal conductor contains any metal of gold, silver and copper.

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