JPH04342920A - metal halide lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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, and more particularly to a metal halide lamp that is used only with an arc tube without an outer tube and is lit in a horizontal position while being cooled by air.

0002

2. Description of the Related Art Conventionally, small metal halide lamps, which were used only with an arc tube without an outer tube, have been used together with lenses and reflectors as light sources for overhead projectors (OHP) and movie projectors, and are gradually becoming popular. In recent years, it has become popular as a light source for projection televisions and the like that use liquid crystals.

When this type of metal halide lamp is lit horizontally, the arc tube is placed inside the outer bulb and the metal halide lamp is lit in a vacuum state within the outer bulb.When the metal halide lamp is lit horizontally, the temperature difference between the top and bottom of the arc tube is approximately There is a large temperature difference of about 120°C compared to 40°C. The temperature at the top of the arc tube is higher than any other part of the arc tube, and the quartz, which is the material for forming the arc tube, chemically reacts with the encapsulated halide and devitrifies, creating an optically usable straight line. Since the light is significantly reduced, the lifetime of optical metal halide lamps was determined by the temperature at which the lamp devitrified.

On the other hand, the temperature of the lower part of the arc tube is the temperature of the coldest part, which is a factor that determines the vapor pressure of the halide to be added and the set temperature must be maintained. Therefore, it is necessary to take measures to bring the temperature of the upper part of the arc tube closer to the lower part of the arc tube, while maintaining the temperature of the lower part of the arc tube at the set temperature.

Conventionally, as a countermeasure against this problem, an air blowing mechanism was provided as shown in FIG. 3 to cool the upper part of the arc tube. That is, a cap 4 is provided at one end of a metal halide lamp consisting of an arc tube 1 with a heat insulating film 2 provided on the outer circumferential surface of the electrode arrangement portion and a trigger wire 3 for starting, and the cap 4 is attached to a mounting base 5 with screws. The arc tube 1 was fixed, and a blower nozzle 6 was fixed and arranged at the upper part of the base 4 of the arc tube 1 with a mounting screw 7, so that air was blown from the blower nozzle 6 to the upper part of the arc tube 1. . In addition, in Figure 3,
8 is a mounting terminal, and 9 is a ventilation duct.

[0006]

[Problems to be Solved by the Invention] By the way, as described above, by providing an air blowing mechanism independent of the arc tube and blowing air to the arc tube, the life of the light source when used as an optical light source can be extended. However, if a blower mechanism is installed independently of the arc tube, the installation position of the air nozzle relative to the arc tube may vary, which may affect the temperature of the coldest part at the bottom of the arc tube, making it impossible to obtain the set temperature. There have been problems in that predetermined color characteristics may not be obtained, and the highest temperature cannot be efficiently cooled, resulting in cases where the expected lifespan may not be obtained.

The present invention has been made to solve the above-mentioned problems in conventional metal halide lamps with a blower mechanism, and while maintaining the temperature of the coldest part at a predetermined temperature, the temperature of the upper part, which is the highest temperature, can be reduced to approximately The purpose of the present invention is to provide a long-life metal halide lamp that can be lowered to a similar temperature and has less variation in characteristics.

[0008]

[Means and Effects for Solving the Problems] In order to solve the above-mentioned problems, the present invention provides a metal halide lamp that is used only with an arc tube without an outer bulb and is lit in a horizontal state, at one end of the arc tube. It is constructed by attaching a base with a cooling air nozzle integrally provided on the upper part.

[0009] Since the cooling air nozzle is integrally provided with the base, there is no need for fine adjustment of the mounting angle, etc., and variations in the mounting position are eliminated, making it possible to blow air to a specific part, and to achieve the lowest temperature. It is possible to cool the hottest part without variation while maintaining the temperature of the part at a predetermined value, and it is possible to realize a long-life metal halide lamp with little variation in characteristics.

0010

[Example] Next, an example will be explained. FIG. 1 is a perspective view showing an embodiment of a metal halide lamp according to the present invention, and members that are the same or equivalent to those of the conventional example shown in FIG. 3 are denoted by the same reference numerals. The arc tube 1 of this embodiment consists of a spheroidal quartz container with a maximum outer diameter of 11.0 mm, a maximum inner diameter of 8.8 mm, an arc length of 5.0 mm, and an internal volume of approximately 0.4 cc. Dysprosium iodide, neodymium iodide, and cesium iodide each in a weight ratio of 4
In addition to 0.6 mg of mercury iodide selected as 2:3 and 0.2 mg of mercury iodide to contract the arc, about 2 x 104 Pascal of argon as a starting auxiliary gas and mercury as a buffer gas. Contains 10mg. To keep the end warm, a heat insulating film 2 made of a mixture of alumina and silica is coated on the outer circumferential surface of the electrode, and a trigger wire 3 is attached to the outer circumference of the arc tube 1 to act as a proximal conductor during startup. wrapped around it. A terminal 8 for power supply is provided at one end of the arc tube 1, and a terminal 8 with a height of 3 mm is provided at the other end.
, a base 12 having an opening 11a having a width of 7 mm and a lower side longer than the upper side integrally formed on the upper side is attached so as to be able to blow air toward the upper part of the arc tube. By attaching the cap 12 to the mounting base 5, the arc tube 1 is maintained in a horizontal state and fixed at a predetermined position.

[0011] When the arc tube 1 of the metal halide lamp constructed as described above is lit with a rectangular waveform electronic ballast having a frequency of 150 Hz, the temperature of the lower coldest part at the initial stage of lighting is as low as the ambient temperature of 20°C. and when there is no air blowing, 84
Indicates 0°C. The color characteristics at this point are the color rendering index Ra
It has a color temperature of 88 and a color temperature of 6500K, and has excellent characteristics as a video light source.

[0012] In this case, the highest temperature on the upper side is 960
℃, and if it is turned on without air blowing, it will be about 4℃.
After 00 hours, the upper quartz container, which is the hottest part, is deformed by internal pressure and not only suffers from significant devitrification but also swells.

[0013] Therefore, 0.1 kg/cm2 is applied to the air duct 9.
A mechanism is provided to send air at a pressure of
When the air was blown at a speed of 0.5 m/sec at the top of the arc tube and the temperature at the top and bottom of the arc tube was measured again, the temperature at the bottom was slightly lower by 2 degrees Celsius, and at the top it was 850 degrees Celsius, a decrease of 110 degrees Celsius. There was found.

[0014] Ten arc tubes with the above configuration each having a cap with a blowing nozzle were made, and the temperature change at the top and bottom of the arc tube was measured by blowing air in the same manner as above.
It was found that the temperature in the upper part was significantly lowered within a small variation of 100 to 115 °C. Further, when the optical color characteristics were measured, there were few variations, and the color temperature was in the range of 6,700 to 6,500, and the Ra was in the range of 88 to 86, showing good characteristics. Furthermore, when a life test was conducted, it was confirmed that a long-life arc tube with a slow devitrification rate, in which the light distribution did not change much, was obtained.

In order to compare with the above embodiment, 10 metal halide lamps of the conventional configuration equipped with the independent air blowing mechanism shown in FIG. The temperature decreases in the range of 920 °C to 840 °C, and the lower temperature also decreases in the range of 837 °C to 780 °C, with large variations.Therefore, the color characteristics also significantly change, with the color temperature ranging from 8500 K to 6500 K, and Ra ranging from 67 to 88. It was found that many of them fluctuated and showed low commercial value, making them unsuitable for practical use.

Next, another embodiment will be explained based on FIG. In this embodiment, in the embodiment shown in FIG.
Mounting base 5 for base 12 integrally formed with blower nozzle 11
A reflecting mirror 21 with a cold mirror is attached to the base 12 via fixing cement 22 so that the base 12 is located at the bottom and surrounds the arc tube 1. In addition, in FIG. 2, 23 is a lead wire, 2
4 is a double terminal, and 25 is a mounting terminal.

The reflecting mirror 21 has a diameter of 10 mm with F=13 mm.
This is a 0 mm parabolic reflector, and when a horizontal lighting experiment was conducted in the same manner as in the example shown in FIG. 1, it was confirmed that similar color characteristics and life characteristics with less variation could be obtained. Furthermore, when the illuminance maintenance rate was measured by projecting it onto a screen, it was found that a high illuminance maintenance rate of 70% could be obtained after 2000 hours of lighting.

[0018]

[Effect of the invention] As explained above based on the embodiments,
According to the present invention, since the blower nozzle is integrally provided with the base, there is no variation in the attachment position of the blower nozzle, and
It becomes possible to blow air to cool specific parts of the arc tube, and while maintaining the temperature of the coldest part at a predetermined value, the temperature of the hottest part can be uniformly cooled, resulting in a long-life metal halide lamp with little variation in characteristics. be able to.

[Brief explanation of the drawing]

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

FIG. 2 is a partially cutaway perspective view showing another embodiment of the present invention.

FIG. 3 is a perspective view showing a configuration example of a conventional metal halide lamp.

[Explanation of symbols]

1 Arc tube 2 Heat insulation membrane 3 Trigger wire 5 Mounting base 8 Mounting terminal 9 Air duct 11　Blower nozzle 11a Opening 12 Base 21 Reflector

Claims (2)

[Claims] [Claim 1] Used only with an arc tube without an outer tube,
In metal halide lamps that are lit horizontally,
A metal halide lamp characterized in that a cap having a cooling blow nozzle integrally provided in the upper part is attached to one end of the luminous tube. [Claim 2] Used only with an arc tube without an outer tube,
In metal halide lamps that are lit horizontally,
A metal halide lamp characterized in that a base having a cooling blow nozzle integrally provided at the top is attached to one end of the arc tube, and a reflector is provided so that the base is located at the bottom and surrounds the arc tube. .