JPH0554861A - Metal halide lamp equipped with air blowing mechanism - Google Patents

Abstract

PURPOSE:To enhance the rate at which illuminance of a light-emitting tube is maintained by lowering the speed of devitrification of the light-emitting tube. CONSTITUTION:To one of the sealed portions of a light-emitting tube 1 having main electrodes 2 provided at both ends thereof, a reflecting and heat-retaining film 3 is applied in such a way as surrounding the main electrodes 2 and a base 4 having an air blowing nozzle 5 integrally provided on one side portion thereof is mounted to the other opposite sealed portion in such a manner that the axis of the air blowing nozzle 5 is parallel to the axis of the light-emitting tube 1. Also the cross section 5a of the air blowing nozzle 5 is superimposed on more than 10% of the upper side of the maximum diameter cross section 1a of the light-emitting tube 1. Cooling air is fed from an air duct 8 and blown parallel to the axis of the light-emitting tube and toward the upper portion of the light-emitting tube so that the tube is cooled.

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 having a blower mechanism which is used only as an arc tube without providing an outer tube and is used as a relatively small image light source. ..

[0002]

2. Description of the Related Art Conventionally, a short arc metal halide lamp, which is used only by an arc tube without providing an outer tube, is characterized by its good color rendering properties and high luminous efficiency.
It is being used widely as a light source for video equipment using an optical system, such as an overhead projector, an overhead type liquid crystal projector or a liquid crystal projection television, and a projector.

As described above, a small-sized metal halide lamp for an image, which is used only in the arc tube without providing the outer tube, uses a rare earth metal halide, and has a large capacity of the lamp power with respect to the internal volume of the arc tube, and is enclosed in the arc tube. The additive vapor pressure is set to a value almost the same as that of a metal halide lamp provided with an outer tube so as to obtain good color characteristics.

[0004]

However, since the lamp power per volume inside the arc tube is large, the enclosed rare earth metal halide reacts with the quartz material forming the arc tube container, and devitrification occurs especially at high temperatures. The phenomenon occurs early.
When the arc tube is arranged horizontally for lighting, the uppermost part of the arc tube becomes the hottest part, so devitrification in this part becomes remarkable, and when irradiating the screen as the image light source,
There is a problem that the illuminance on the screen is significantly deteriorated and the commercial value is lost early.

The present invention has been made in order to solve the above-mentioned problems in a conventional metal halide lamp in which an arc tube enclosing a halide containing at least a rare earth metal is provided horizontally without an outer tube and is lit. Things
An object of the present invention is to provide a metal halide lamp device equipped with an air blowing mechanism that suppresses the devitrification rate due to the reaction with a rare earth metal halide in the highest temperature part of the arc tube, delays the decrease in screen illuminance, and improves the life characteristics. To do.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is designed so that an arc tube in which a halide containing at least a rare earth metal is sealed is not provided and the arc tube is horizontally lit. In the metal halide lamp device described above, the cooling blower nozzle is arranged such that the nozzle axis is parallel to the tube axis of the arc tube and the nozzle cross section overlaps 10% or more from above the maximum diameter transverse cross section of the arc tube. is there.

In the metal halide lamp device thus constructed, the upper part of the arc tube, which is the highest temperature part of the arc tube, is efficiently cooled by the blowing nozzle, and the devitrification speed of the arc tube container due to the reaction with the rare earth metal halide is increased. Suppressed,
The life characteristics can be improved.

[0008]

EXAMPLES Next, examples will be described. 1 is a partially cutaway perspective view showing an embodiment of a metal halide lamp device according to the present invention. FIG. 2A is a perspective view of a main part thereof, and FIG. It is explanatory drawing which shows the overlapping aspect of a cross section and a nozzle cross section. In the figure, reference numeral 1 is a quartz arc tube equipped with main electrodes 2 and 2 supported by seals on both ends, the internal volume of which is approximately 0.4 cc, the maximum outer diameter is φ11 mm, the maximum inner diameter is φ8.8 mm, and the arc. The length is set to 5.0 mm, and about 1 mg of dysprosium iodide, neodymium iodide, and cesium iodide in a weight ratio of 4: 2: 3 is used. 150 torr and mercury
Contains 10 mg.

A white oxide reflecting and heat retaining film 3 is applied to one seal portion so as to surround the main electrode 2 provided on that side. Further, a mouthpiece 4 having a blower nozzle 5 integrally provided on one side is attached to the opposing seal portions so that the nozzle axis of the blower nozzle 5 is parallel to the tube axis of the arc tube 1. The cross section 5a of the blower nozzle 5
2A, as shown in FIG. 2B, the arc tube 1 is configured so as to overlap by 10% or more from above the maximum diameter cross section 1a. Then, the arc tube 1 having the above-described structure is attached to the base 4 thereof.
Is attached to the reflecting mirror 6 provided with a dielectric film on the inner side, the power supply lead wire 7 is connected to one end of the base 4, and the cooling air is connected to the base of the blower nozzle 5. A duct 8 is provided for feeding.

The metal halide lamp device constructed as described above is horizontally arranged and lit by a rectangular wave electronic ballast with a rated power of 150 W lamp. 2 liters of cooling air is supplied from the air duct 8 connected to the air blowing nozzle 5 per minute, and is blown from the air blowing nozzle 5 toward the upper part of the arc tube in parallel with the arc tube axis. As a result, the upper part of the arc tube, which is the highest temperature part, is effectively cooled, the devitrification speed is suppressed, and the deterioration of the screen illuminance is reduced.

Next, an experiment conducted for confirming the action and effect of the present invention will be described. When the metal halide lamp is horizontally arranged and lit, the temperature of the lower outer surface of the arc tube is almost equivalent to the temperature of the coldest part, and the lamp voltage and color characteristics are determined. In the metal halide lamp device configured as in the above example, when no air is blown, the surface temperatures of the upper and lower parts of the arc tube are 945 ° C. and 835 ° C., respectively,
It shows characteristics depending on the temperature of the coldest part, _Ra is 85, and x, y chromaticity coordinates are (0.295, 0.330), indicating good color characteristics. However, the temperature of the outer surface of the upper part of the arc tube is high,
As a result, as described above, there is a problem that the reaction with the rare earth metal is large, the devitrification rate is large, and the screen illuminance maintenance rate is significantly reduced.

Next, when blowing 2 liters per minute from the nozzle toward the arc tube, the nozzle axis is not parallel to the axis of the arc tube, but the air blown from the nozzle reaches the lower side of the seal portion of the arc tube. If so, _Ra is 67 and the x, y chromaticity coordinates are about (0.260, 0.295), which is a characteristic that cannot be used as a light source for video. Therefore, unless the nozzle is provided so that the nozzle axis is parallel to the arc tube axis, the root of the seal part may be cooled by the air blow, and the coldest part may be formed in the electrode peripheral part near the nozzle. I was confirmed. Therefore, it has been found that arranging the nozzles in parallel with the arc tube axis is a requirement for not adversely affecting the coldest part.

Next, a description will be given of an experiment conducted on the overlapping ratio of the nozzle cross section to the maximum cross section of the arc tube when the nozzle is arranged parallel to the arc tube axis.
FIG. 3 is a diagram showing changes in the screen illuminance maintenance rate during the life test, where a is the characteristic when no air is blown, and b is the nozzle arranged so that the nozzle cross section overlaps 5% from the upper side of the arc tube maximum diameter cross section. The characteristics when air is blown in the same manner, c is the same 10% overlap, and d is the same 30% overlap. As can be seen from these characteristic curves, when the nozzles are arranged so that the nozzle cross sections overlap 10% or more from above the maximum diameter transverse cross section of the arc tube, the illuminance retention rate is good and the devitrification rate is reduced. It turned out to be possible. Therefore, in the present invention, the cooling blast nozzle is arranged so that the nozzle cross sections overlap with each other by 10% or more from above the horizontal cross section of the arc tube maximum diameter.

In the above examples, dysprosium iodide and neodymium iodide were used as rare earth metal halides, but rare earth metal halides such as lutetium, holmium and thulium are also used. When a life test was performed, it was confirmed that similar illuminance maintenance rate characteristics were obtained.

[0015]

As described above on the basis of the embodiments,
According to the present invention, the upper part of the arc tube, which is the highest temperature part of the arc tube, is efficiently cooled, the devitrification speed of the arc tube is suppressed, and the illuminance maintenance rate can be improved.

[Brief description of drawings]

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

FIG. 2 is a perspective view of a main part of the metal halide lamp device shown in FIG. 1 and a diagram showing an overlapping mode of a cross section of a maximum diameter of an arc tube and a nozzle cross section.

FIG. 3 is a diagram showing a change in screen illuminance maintenance rate during a life test.

[Explanation of symbols]

 1 Arc tube 2 Main electrode 3 Reflective and heat insulating film 4 Base 5 Blower nozzle 6 Reflector 8 Duct

Claims (1)

[Claims] 1. A metal halide lamp device in which an arc tube enclosing a halide containing at least a rare earth metal is not provided, and the arc tube is arranged horizontally for lighting. The nozzle axis is parallel to the tube axis of the arc tube. In addition, a metal halide lamp device provided with an air blowing mechanism, characterized in that the cooling air blowing nozzles are arranged so that the nozzle cross sections overlap with each other by 10% or more from above the maximum diameter transverse cross section of the arc tube.