JP2012234764A - Flash irradiation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flash irradiation device which cools a flash lamp and prevents the damage of a luminous tube.SOLUTION: A flash irradiation device includes: a flash lamp having a luminous tube made of quartz glass and a cooling device of the flash lamp. The flash irradiation device includes: temperature measuring means provided on a surface of the luminous tube; and a control part cooling the cooling mechanism. The surface temperature of the luminous tube is controlled so as to be 300 to 500°C.

Description

  The present invention relates to a flash irradiation apparatus using a flash lamp, and more particularly to a high-power, high-load flash irradiation apparatus that is used for exciting a solid-state laser and that cools the flash lamp.

In general, in a laser apparatus using a solid-state laser such as a YAG laser, a flash irradiation apparatus equipped with a flash lamp is used as excitation means for exciting the solid-state laser. Such a flash irradiation device is composed of a flash lamp body and a cooling mechanism thereof, as is known, for example, in Patent Document 1.
In the flash lamp, a pair of electrodes are arranged opposite to each other inside a substantially straight tube arc tube, and a rare gas such as krypton or xenon is sealed inside the arc tube.

A conventional flash lamp will be described with reference to FIG.
In the high input type, the arc tube of the flash lamp 50 is mainly composed of quartz glass, and has a pair of electrodes composed of tungsten, tungsten containing thorium oxide, lanthanum oxide, barium oxide compound, or the like. ing.
Since a high load is applied to the lamp, a cooling medium flow path 51 that normally covers the outer periphery of the arc tube is provided, and a cooling fluid is circulated to be lit while being cooled.
In this way, by cooling the flash lamp 50, even when high power is input and the lamp is lit, it can be maintained below the heat-resistant temperature of the quartz glass constituting the arc tube, and the life can be made relatively long. it can.

JP 2006-260795 A

However, when the flash lamp was lit at high input while cooling the flash lamp as described above, there was a problem that the arc tube was damaged.
As a cause of this, the intensity of ultraviolet rays generated from the flash lamp is increased due to the increase in input power, and the temperature of the arc tube is lowered, which makes it easy to add ultraviolet distortion to the arc tube. It was speculated that
Conversely, when the flash lamp is not cooled, the electrode temperature becomes excessively high and wear due to evaporation occurs, or the inner surface of the quartz glass constituting the arc tube becomes hot and is reduced, resulting in a decrease in light transmission. Or it became hotter and evaporated and became cloudy.
In view of the above, an object of the present invention is to provide a flash irradiation device capable of preventing the arc tube from being damaged while cooling the flash lamp.

  In order to solve the above-mentioned problems, the present invention provides a flash emission device comprising a flash lamp whose arc tube is made of quartz glass and a cooling mechanism for the flash lamp, wherein the flash emission device is disposed on the surface of the arc tube. A temperature measuring means provided and a controller for controlling the cooling mechanism are provided, and the temperature of the surface of the arc tube is controlled to 300 to 500 ° C.

  According to the present invention, the temperature information is obtained by the temperature measuring means provided on the outer surface of the flash lamp, and the control unit controls the cooling mechanism based on the temperature information, and the flash lamp electrode is worn out or emits light. While cooling so that the light transmittance of the tube does not decrease, it is possible to prevent the arc tube from being ruptured by ultraviolet distortion.

It is a figure which shows the flash lamp which concerns on this invention. It is a figure which shows the structure of the flash irradiation apparatus which concerns on this invention. It is a figure shown about the temperature control of the flash lamp of the flash irradiation apparatus which concerns on this invention. It is a figure which shows the experimental result which concerns on the flash irradiation apparatus which concerns on this invention. It is a figure which shows the structure of the flash irradiation apparatus which concerns on a prior art example.

The flash emission device of the present invention will be described below with reference to the drawings.
FIG. 1 is a view showing a flash lamp according to the present invention.
The flash lamp 10 includes a cathode 12 and an anode 13 which are a pair of electrodes made of a refractory metal such as tungsten, for example, inside an arc tube 11 in which both ends of a long straight tubular quartz glass tube are sealed.
The cathode 12 and the anode 13 are physically supported by the external leads 14 and 15 and are electrically connected. Power is supplied from a power supply device (not shown) connected to the external leads 14 and 15.
The outer leads 14 and 15 are arranged so that the outer ends thereof are embedded in the seals S at both ends of the arc tube 11 and project outside the arc tube.
A rare gas such as xenon is sealed in the arc tube.

On both ends 11A and 11B in the arc tube 11 of the flash lamp 10, reduced diameter portions 17 and 18 are formed by reducing the diameter of the arc tube 11 in the vicinity of the electrodes 12 and 13.
The diameter-reduced portions 17 and 18 are provided to facilitate cooling by bringing the electrode into close contact with the arc tube by a cooling mechanism described later.

FIG. 2 is a diagram showing an example of the configuration of the flash radiation device according to the present invention.
The flash radiation device 2 includes a flash lamp 10 and a cooling mechanism.
The cooling mechanism is a water-cooled cooling device in this example, and includes a cooling jacket 26, supports 2A and 2B that support the flash lamp, and a water supply device (not shown).
The flash lamp 10 and the cooling mechanism are connected by a structure as described below, for example.
The flash lamp 10 is inserted into a cooling jacket 26 made of a quartz glass cylindrical tube, and both ends thereof are arranged so as to protrude from both sides of the cooling jacket 26.
Supporters 2A and 2B are disposed on both sides of the cooling jacket 20. The support 2A is composed of a substantially disc-shaped support tool main body 23A having a through hole in the center, a clamping plate 26b disposed inside the support tool main body 23A, and a clamping plate 26a disposed outside. Yes. In addition, since it is the same structure also about the support tool 2B, description is abbreviate | omitted.

An O-ring 27a made of an elastic member is disposed between the outer surface of the support tool main body 23A, the fastening plate 26a, and the outer surface of the end portion of the flash lamp 10.
By tightening the screw 25a, the space between the outer surface of the support tool body 23A and the fastening plate 26a is narrowed, and the O-ring 27a is pressed against the outer surface of the end of the flash lamp 10, and the support tool 2A, the flash lamp 10 and Is fixed watertight.
Similarly, an O-ring 27b made of an elastic member is disposed between the inner surface of the support body 23A, the fastening plate 26b, and the outer surface of the end portion of the cooling jacket 20.
By tightening the screw 25b, the O-ring 27b is pressed against the outer surface of the end portion of the cooling jacket, and the support 2A and the cooling jacket 20 are fixed.

A hole that opens to the outside is formed inside the support 2A. This communicates with the internal space of the connected cooling jacket 20 to form a cooling medium introduction path 28.
Similarly, a hole that opens to the outside is formed inside the support 2B, and the cooling medium discharge path 29 is formed by communicating with the internal space of the connected cooling jacket 20.
A space between the cooling jacket 20 and the flash lamp 20 serves as a cooling medium flow path 21.
As the cooling medium, water can be used, and in addition to water, gas or air may be used.

A temperature measuring means 22 is provided on the outer surface of the flash lamp 10. The temperature measuring means 22 is a thermocouple composed of a pair of different metal wires such as alumel-chromel. Thereby, the temperature of the outer surface of the flash lamp 10 can be measured.
Temperature measuring means introducing portions 231A and 231B are provided in the support tools 2A and 2B, and the temperature measuring means 22 can be introduced into the cooling medium flow path 21.

The cooling mechanism configured as described above introduces a cooling medium from a water supply device (not shown) through the cooling medium introduction path 28 of the support 2A, and flushes the cooling medium by flowing the cooling medium in the direction of the arrow shown in the drawing. The periphery of the outer surface of the lamp 10 can be cooled directly.
The temperature measuring means 22 can measure the temperature of the outer surface of the arc tube 11 of the flash lamp 10.

FIG. 3 shows the temperature control of the flash lamp of the flash radiation device.
The temperature measuring means 22 provided on the surface of the flash lamp 10 acquires temperature information and sends it to the control unit 30.
Since the control unit 30 stores a predetermined temperature preferable for lighting the flash lamp 10, the control unit 30 controls the cooling mechanism 31 so that the temperature of the outer surface of the flash lamp 10 becomes a predetermined temperature.
For example, when it is determined that the acquired current temperature is higher than a predetermined temperature, the cooling is strengthened by increasing the flow rate of the cooling medium. If it is determined that the acquired current temperature is lower than the predetermined temperature, the cooling is weakened by, for example, reducing the flow rate of the cooling medium.

Next, the predetermined temperature preferable for lighting the flash lamp will be described.
FIG. 4 shows the number of times of lighting (shots) and the number of times that the flash lamp is lit while cooling the flash lamp at various temperatures using the flash emission device shown in FIGS. It is a figure showing the relationship with the distortion which is. The larger the strain angle, the larger the strain amount.
The quartz glass used for the arc tube of the flash lamp accumulates distortion due to ultraviolet rays contained in its own light emission every time the lighting is repeated. If the ultraviolet distortion accumulated in the arc tube exceeds a certain value, the arc tube will burst. For example, when the strain angle is about 60 to 70 degrees or more, the arc tube is exposed to a risk of bursting.
The crosses indicated on the graph indicate that rupture occurred due to accumulation of strain in the arc tube.

Referring to FIG. 4, when the temperature was 100 ° C., the strain increased rapidly even with a small number of shots, and bursting occurred at a total of about 100 shots. This is presumably because when the temperature of the arc tube is low, ultraviolet distortion is more likely to accumulate than when it is high, and it bursts early.
In addition, strain gradually accumulated when the temperatures were 200 ° C. and 250 ° C., and when the strain angle exceeded about 60 degrees, bursting occurred thereafter.
On the other hand, at 300 ° C., even when the number of shots increased, the accumulation of strain was difficult to extend beyond a certain level, and no burst occurred even when the number exceeded 200 × 10 ⁴ shots.

Thus, when the number of shots was increased at 300 ° C. or higher, such as 400 ° C. or 500 ° C., the arc tube did not rupture.
However, when the temperature of the arc tube exceeds 500 ° C., there is another problem that the light transmittance of quartz glass decreases from the ultraviolet region, and as the temperature increases, the light transmittance decreases to the visible light region. End up. For this reason, it is not preferable to light the flash lamp at a temperature exceeding 500 ° C.

  As described above, the lighting temperature of the flash lamp is preferably 300 to 500 ° C. By cooling the flash lamp so as to be within this temperature range, the electrode of the flash lamp is worn out or the light transmittance of the arc tube is reduced. The arc tube can be prevented from bursting due to ultraviolet distortion while cooling so as not to occur.

DESCRIPTION OF SYMBOLS 10 Flash lamp 11 Arc tube 11A End part 11B End part 12 Cathode 13 Anode 15 External lead 16 External lead 17 Reduced diameter part 18 Reduced diameter part S Seal part 2 Flash emission device 20 Water cooling jacket 21 Cooling medium flow path 22 Temperature measurement means 23A Support tool body 23B Support tool body 25a Screw 25b Screw 26a Clamping plate 26b Clamping plate 27a O-ring 27b O-ring 28 Cooling fluid introduction channel 29 Cooling fluid discharge channel 30 Control unit 31 Cooling mechanism 50 Flash lamp 51 Cooling medium channel 51
56 Cooling jacket

Claims (1)

A flash lamp whose arc tube is made of quartz glass;
In a flash radiation device equipped with a flash lamp cooling mechanism,
The flash radiation device comprises:
Temperature measuring means provided on the surface of the arc tube;
A control unit for controlling the cooling mechanism,
A flash emission device characterized in that the temperature of the surface of the arc tube is controlled to 300 to 500 ° C.

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