JPH06111771A - Metal halide lamp and associate projector device - Google Patents

Abstract

PURPOSE:To provide a metal halide lamp and an associate projector device which can prevent devitrification of a light emitting tube without inducing drop of the chromatic temp. of the lamp. CONSTITUTION:Metal halides and rare gas are encapsulated in the light emitting tube 20 of a metal halide lamp 1, wherein the metal halides are mixture of at least rare earth metal halide and tin halide, and the mol ratio in encapsulation of the former halide to the latter is set as ranging from 1:0.3 to 1:1. Thereby the encapsulation amount of tin halide is made proper, so that a metal halide lamp is obtained in which the light emitting tube is prfecluded from devitrification without inducing drop of the chromatic temp. of the lamp, and also drop of the screen illuminance 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 effective as a light source for a color liquid crystal projector device,
The present invention also relates to a projector device using the same.

[0002]

2. Description of the Related Art The basic principle of a color liquid crystal projector which has recently been put into practical use is as shown in FIG. 2, in which a light source 1, a reflector 2 for reflecting the light emitted from the light source, and a reflector for reflecting the light are emitted. It is provided with a condenser lens 3 for condensing light.

The light projected from the condenser lens 3 is reflected by a dichroic mirror (wavelength selective reflecting mirror) 4 which reflects blue light, and is reflected by a mirror 5 to illuminate a liquid crystal panel 6. The image on the liquid crystal panel 6 is colored blue and projected on the screen 10 through the dichroic mirrors 7 and 8 and the projection lens 9.

Of the light projected from the condenser lens 3, the red and green lights pass through the dichroic mirror 4 which reflects blue light, and the red light among them is reflected by the dichroic mirror 11. The liquid crystal panel 12 is illuminated, and the image on the liquid crystal panel 12 is colored red and projected onto the screen 10 via the dichroic mirror 8 and the projection lens 9.

Further, the green light transmitted through the dichroic mirror 11 that reflects the red light illuminates the liquid crystal panel 13, and the image on the liquid crystal panel 13 is colored green.
This green image is reflected by the mirror 14 and the dichroic mirror 8 and projected on the screen 10 via the projection lens 9.

Therefore, the three liquid crystal panels 6, 12,
By adjusting the image of 13, the images of the three primary colors are superimposed and projected on the screen, and the color image is projected.

As a light source of the color liquid crystal projector device thus constructed, a metal halide lamp having a large light output, a high luminous efficiency, an excellent color rendering property, and a good life characteristic is used.

In this metal halide lamp, as shown in FIG. 1, a pair of electrodes 21 and 21 are sealed in an arc tube 20 made of quartz glass or the like, and these electrodes 21 and 21 are externally lead via metal foil conductors 22 and 22. It is connected to the lines 23, 23. The illustrated metal halide lamp is of a sealed type at both ends, and the sealed portions 24, 24 are provided at both axial ends of the arc tube 20.
And the metal foil conductors 22, 22 are sealed to the sealing portions 24, 24, and the sealing portions 2
The caps 25, 25 connected to the external lead wires 23, 23 are attached to 4, 24.

The arc tube 20 is filled with mercury as a buffer metal, a metal halide as a light emitting metal, and a rare gas such as argon.

As the metal halide, sodium N
Alkali metal halides represented by a and lithium Li are known, but when a rare earth metal halide such as scandium Sc, dysprosium Dy, holmium Ho, and thulium Tm is used, the luminous efficiency is further improved and the color temperature is improved. Has an advantage that the correlated color temperature can be set to 5000 K or more.

However, the rare earth metal halide may react with the high temperature quartz glass during lighting to devitrify the arc tube 20.

That is, for example, when ScI3 is used, the free ScI3 which is excessive during lighting reacts with the quartz (SiO2) of the arc tube to produce SiI4 and ScO2, which causes devitrification of the bulb. Is.

Further, this SiI4 adheres to the tip of the electrode to form a low melting point alloy of tungsten W and silicon Si,
This alloy adheres to the wall of the arc tube and becomes a cause of blackening. Such devitrification and blackening lowers the luminous flux of the lamp, so that the luminance is lowered, and thus the light collection rate of the reflecting mirror 2 is lowered, and the illuminance of the screen is lowered.

In order to improve such a problem, the applicant of the present invention has disclosed that in Japanese Patent Application No. 1-28039, in addition to a halide of a rare earth metal, a halide of tin such as Sn.
It has been proposed that devitrification is significantly reduced by adding and encapsulating I2.

However, if the amount of tin halide enclosed is not proper, the effect of preventing devitrification may be poor,
It has also been found that the increase in the light emission of tin halide induces a decrease in the color temperature of the lamp.

[0016]

SUMMARY OF THE INVENTION Therefore, the present invention provides a metal halide lamp capable of preventing devitrification of an arc tube without inducing a decrease in the color temperature of the lamp even when a tin halide is enclosed, and a metal halide lamp therefor. An object of the present invention is to provide a projector device using the.

[Structure of the Invention]

[0018]

In order to solve the above problems, in the metal halide lamp according to the present invention, a pair of electrodes are provided inside the arc tube, and a metal halide and a rare gas are contained in the arc tube. The metal halide is a mixture of at least a rare earth metal halide and a tin halide, and the rare earth metal halide and the tin halide have an enclosed molar ratio of 1: 0.3 to It is characterized by having a relationship of 1: 1.

In the projector device according to the second aspect of the present invention, the light source is a metal halide lamp in which a pair of electrodes are provided inside the arc tube, and a metal halide and a rare gas are enclosed in the arc tube. Therefore, the metal halide enclosed in this metal halide lamp is a mixture of at least a rare earth metal halide and tin halide, and the enclosed molar ratio of the rare earth metal halide and tin halide is 1: 0.3. It is characterized by having a relationship of 1 to 1: 1.

[0020]

According to the invention described in this claim, since the amount of the halogen halide of tin is optimized, the metal halide lamp and the metal halide lamp capable of preventing the devitrification of the arc tube without inducing the decrease of the color temperature of the lamp. By using, it is possible to provide a projector device capable of reducing the decrease in screen illuminance.

[0021]

Embodiments of the present invention will be described below with reference to the characteristic diagram of FIG. 3 and the drawings described above.

The overall structure of the projector device is as shown in FIG. 2, and the metal halide lamp structure specified as the light source thereof is as shown in FIG.

As shown in the figure, the metal halide lamp 1 of this embodiment is, for example, a lamp power of 250 W, a lamp voltage of 85 V, and a lamp current of 2.94 A in which the inner volume of the arc tube 20 is about 1 cc. The electrodes 21 and 21 sealed in the arc tube 20 are composed of an electrode shaft 26 and an electrode coil portion 27, respectively.

The electrode shaft 26 is made of tungsten having a wire diameter of 0.7 mm, and the electrode coil portion 27 attached to the tip of the electrode shaft 26 is made of tungsten wire having a wire diameter of 0.5 mm.
It is formed by winding 5 times.

The distance between the tips of the electrodes 11, 11, that is, the distance 1 between the electrodes is set to 4 to 10 mm.

The arc tube 10 is filled with mercury as a buffer metal, a metal halide, and a predetermined amount of a rare gas such as argon.

In the case of the present embodiment, metal halides are halogens of iodine and bromine, dysprosium Dy, tin S.
n, indium In, thallium Tl, and cesium Cs are encapsulated, so that DyI3, D
yBr3, SnI2, InBr, InI, TlBr, T
II, CsBr, and CsI are enclosed.

Here, among the above metal halides, the rare earth metal halide and tin halide are enclosed so that the molar ratio is, for example, 1: 0.7, and the rare earth metal per unit volume of the arc tube. The enclosed amount of the metal halide is, for example, 3 × 10 -6 mol.

The metal halide lamp having such a structure has a rotating quadric surface formed by depositing a thin film metal oxide such as TiO2 --SiO2 having excellent reflectivity on the inner surface of a glass structure having an opening diameter of 90 to 130 mm. A base 25 is mounted and fixed on the substantially central axis of the reflector 2 formed of the one with the one sealing portion 24 being inserted.

As described above with reference to FIG. 2, the light emitted from the metal halide lamp 1 is reflected by the reflector 2.
Is reflected by the dichroic mirrors (wavelength selective reflecting mirrors) through the condenser lens 3, and is transmitted through the liquid crystal panel corresponding to each of the split lights.

Each light is reflected by a mirror, condensed by a projection lens, and applied to a screen.

When the color temperature of the radiated light on the screen was measured for the projector device configured as described above, the correlated color temperature was 6000 K, and the lamp efficiency of this metal halide lamp was 80 lm / W, which was a good characteristic. Was obtained.

Further, the inventors of the present invention produced various metal halide lamps in which the inclusion molar ratio of rare earth metal halide and tin halide was changed, and tested them by incorporating them in a projector device. When the amount is relatively large compared to the amount of rare earth metal halide enclosed, the color temperature of the lamp tends to decrease and color unevenness tends to occur. It has been confirmed that when the ratio of encapsulation exceeds 1, the correlated color temperature is lower than 5000 K, and the practical color reproducibility of the projector device cannot be obtained. This is because when the amount of tin halide enclosed becomes relatively large,
It is speculated that this is due to the increase of the spectrum on the long wavelength side, since the light emission by tin halide becomes remarkable.

Regarding the decrease in the illuminance of the screen,
As a result of the experiment, the results shown in FIG. 3 were obtained.
In other words, as shown in the figure, when the amount of tin halide enclosed is smaller than the amount of rare earth metal halide enclosed, the decrease in illuminance increases with the passage of time. Therefore, since the illuminance after 1000 hours has to be maintained at 80% or more of the initial value,
It was found that the tin halide had to be 0.3 or more in molar ratio with respect to the rare earth metal halide. This is considered to be because when the amount of tin halide enclosed is small, the release rate of the rare earth metal halide, which has a high reactivity with quartz during lighting, is large, so that the illuminance is significantly reduced.

Therefore, as described above, in order to prevent the reduction of the illuminance of the screen, in other words, the devitrification of the arc tube without inducing the reduction of the color temperature of the lamp, the rare earth metal halogen enclosed in the metal halide lamp is used. The encapsulation molar ratio of the halide to the tin halide must be 1: 0.3 to 1: 1.

In the above examples, since the metal halide lamp is filled with indium bromide and thallium bromide, the emission intensity near 580 nm, which is close to the resonance line of mercury, is weakened, while the indium and thallium bromides are reduced. Since the intensity of the emission spectrum (450 nm and 570 nm) increases, there is also an advantage that the color reproducibility of the projector device can be improved by matching the wavelength selectivity of the dichroic mirror that separates these lights.

When indium, thallium, or lithium is added and encapsulated as described above, the total encapsulation amount of the halides of these metals is 1 in molar ratio with respect to the encapsulation amount of the rare earth metal halide. It has been confirmed that: 0.5 to 1: 2 is preferable from the viewpoint of color reproducibility.

[0038]

According to the present invention, the amount of tin halide enclosed is optimized so that the devitrification of the arc tube can be prevented without inducing a decrease in the color temperature of the lamp. And by using it,
It is possible to provide a projector device that can reduce a decrease in screen illuminance.

[Brief description of drawings]

FIG. 1 is a schematic view showing a metal halide lamp incorporated in a reflector.

FIG. 2 is a conceptual diagram of a color liquid crystal projector device.

FIG. 3 is a characteristic diagram showing a decrease in screen illuminance.

[Explanation of symbols]

1 ... Metal halide lamp 2 ... Reflector 4, 7, 8, 11 ... Dichroic mirror 6, 12, 13 ... Liquid crystal panel 10 ... Screen 20 ... Arc tube 21 ... Electrode 22
・ ・ ・ Metal foil conductor 23 ・ ・ ・ External lead wire 24 ・ ・ ・ Sealing part 25
... Base 26 ... Electrode shaft 27 ... Electrode coil

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ichiro Tanaka 1-4-4 Mita, Minato-ku, Tokyo Toshiba Lighting & Technology Corporation

Claims (2)

[Claims] 1. A metal halide lamp in which a pair of electrodes are provided inside an arc tube, and a metal halide and a rare gas are enclosed in the arc tube, wherein the metal halide is at least a rare earth metal halide and a halogen. It is a mixture with tin halide, and the enclosed molar ratio of the rare earth metal halide and tin halide is 1:
A metal halide lamp having a relationship of 0.3 to 1: 1. 2. A projector device using, as a light source, a metal halide lamp in which a pair of electrodes are provided in the arc tube, and a metal halide and a rare gas are sealed in the arc tube. Further, the metal halide is a mixture of at least a rare earth metal halide and tin halide, and the enclosed molar ratio of the rare earth metal halide and tin halide is 1: 0.3 to 1: 1.
A projector device having the following relationship.