JPH05135745A - Metal halide lamp device - Google Patents

Abstract

PURPOSE:To provide a metal halide lamp device capable of shortening the restarting time and reducing the restart application pulse. CONSTITUTION:A metal halide lamp is constituted of a metal halide lamp light emitting tube 1 using no outer tube, a variable-air speed blast fan 4 for cooling the light emitting tube 1, and a control device 5 controlling the blast fan 4 to increase its air speed immediately after a lamp is turned off. The restarting time is shortened, and the restart application pulse can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal halide lamp device, and more particularly to a metal halide lamp device provided with a metal halide lamp consisting of an arc tube only without an outer tube and a blowing means for cooling the lamp.

[0002]

2. Description of the Related Art Conventionally, a small short arc metal halide lamp, which is used only by an arc tube without providing an outer tube,
Since it has a high luminous efficiency and a high color rendering property, it is gradually used in overhead projectors (OHPs) and projectors, and is also becoming popular as a light source for video equipment using liquid crystals in recent years.

Since such a short arc metal halide lamp is miniaturized and a large amount of iodide is filled in compared with the internal volume of the arc tube in order to improve color characteristics, a considerable amount of energy is required at the time of starting. However, the safety standard does not allow the starting pulse height to be too high, so conventionally, this has been dealt with by increasing the pulse width and the pulse repetition number at the time of starting.

On the other hand, such a small metal halide lamp has a size close to that of a point light source and is lit with a high load.
The heat resistance is measured by blowing air for about / sec.

[0005]

However, in such a small metal halide lamp, it was found that a high voltage pulse is indispensable when restarting (hot starting) after extinguishing, and a safety standard such as 14 KV is required. There has been a problem that restarting cannot be performed without applying a high-voltage pulse that exceeds.

In order to easily restart the air blown by the air blower after the lamp is turned off, the air is blown at the wind speed at the time of lighting to cool the lamp even after the lamp is turned off.
It takes about 70 seconds until the temperature of the surface of the arc tube, which can be restarted by a high-voltage pulse such as KV, reaches about 120 ° C. Therefore, there is a problem that it takes a considerable time to restart.

The present invention has been made in order to solve the above problems in the conventional metal halide lamp device, and provides a metal halide lamp device capable of shortening the restart time and reducing the restart application pulse. The purpose is to

[0008]

In order to solve the above-mentioned problems, the present invention comprises a metal halide lamp composed only of an arc tube without an outer tube, and a blowing means for cooling the lamp. The metal halide lamp device includes a control device for increasing the air blowing speed of the air blowing means immediately after the lamp is turned off.

[0009]

In a metal halide lamp device provided with an air blowing means, normally, the air is blown at a wind speed (about 0.5 m / sec) at the time of lighting even after the lamp is turned off in order to relight the lamp after turning off the lamp. If a high voltage pulse of 14 KV is applied to re-light in this state, it takes about 70 seconds on average, and the temperature of the arc tube surface at the time of re-lighting is about 120 ° C.

Therefore, in order to shorten the re-lighting time, the wind speed of the blowing means was changed to about 4 m / sec after the light was turned off, and the light was turned on in about 20 seconds. At that time, the surface temperature of the arc tube was about 120 ° C. found. Therefore, it was confirmed that if the surface temperature of the arc tube was increased to a predetermined temperature by cooling the surface of the arc tube and cooled rapidly to a predetermined temperature, the light was turned on again at an early point. Further, it has been found that by increasing the blowing air, the restart time can be shortened and the restart pulse can be reduced. That is, it was confirmed that by restarting with a high-voltage pulse of 8 KV in about 20 seconds, by blowing air at 8 m / sec after cooling and cooling.

Therefore, in the present invention, by providing a control device for increasing the air blowing speed of the air blowing means after the light is turned off as described above, the surface temperature of the arc tube after the light is turned off is quickly cooled, and a low restart pulse is used for a short time. It will be possible to restart with.

[0012]

EXAMPLES Next, examples will be described. FIG. 1 is a schematic perspective view showing an embodiment of a metal halide lamp device according to the present invention. In the figure, reference numeral 1 denotes a quartz arc tube having an internal volume of 0.4 cc, which is a mixed crystal of iodide with a weight ratio of dysprosium iodide, neodymium iodide and cesium iodide of 4: 2: 3.
It is charged with 0.8 mg, mercury 10 mg, argon 200 torr, arc length 5 mm, and a rated power of 150 W using a ballast capable of square wave lighting. The arc tube 1 is attached to a reflecting mirror 2 with a cold mirror having a paraboloid by cement or the like, and ventilation holes 2a and 2b are provided at the edge of the reflecting mirror 2. The ventilation duct 3 is provided in one of the ventilation holes 2a, 2b of the reflecting mirror 2.
The air outlet 3a is inserted, and a variable-speed blower fan 4 is arranged at the base of the blower duct 3. Reference numeral 5 denotes a control device for increasing the voltage applied to the blower fan 4 immediately after the lamp is turned off so as to increase the wind speed of the blower fan 4. In FIG. 1, 6 is a main body of an optical device in which a metal halide arc tube is installed, and 7 is a total reflection mirror for changing an optical path.

In the metal halide lamp device constructed as described above, the surface temperature of the arc tube 1 is about 1000 ° C. in the highest temperature part without wind, but the blower fan 4 blows air at about 0.5 m / sec. The heat resistance is measured by lowering the surface temperature of the arc tube to about 930 ℃ at the highest temperature. After the light is turned off, the air blown by the blower fan 4 is increased to 8 m / sec by the control device 5 in preparation for restarting. This makes about
After 20 seconds, it can be easily relighted with a ballast having a pulse height of 8 KV.

As described above, after the light is turned off, the wind speed of the blower fan is increased to perform the forced air cooling of the arc tube, so that the ballast can be relighted in a short time by using a ballast having a low pulse height. It is possible to use a ballast that can take a short insulation distance, improve the safety of the device, and realize a miniaturized metal halide lamp device which has commercial value and is put on a commercial base. In addition, the parts to be used do not have to consider high pressure, and the cost can be reduced.

[0015]

As described above on the basis of the embodiments,
According to the present invention, it is possible to easily realize a metal halide lamp device capable of shortening the restart time and reducing the restart application pulse.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an embodiment of a metal halide lamp device according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 luminous tube 2 reflecting mirrors 2a, 2b ventilation hole 3 blower duct 4 variable wind speed blower fan 5 control device

Claims (1)

[Claims] 1. A metal halide lamp device comprising a metal halide lamp composed of only an arc tube without an outer tube and a blowing means for cooling the lamp, wherein the blowing speed of the blowing means is set immediately after the lamp is turned off. A metal halide lamp device having a control device for increasing the number.