JPH06342641A - Short arc metal halide lamp - Google Patents

Abstract

PURPOSE:To provide a lamp most suitable for a light source of image projector by achieving well balanced emission in the entire region of visible wavelength, by improving color temperature, and by preventing degradation in brightness which is generated at an early stage. CONSTITUTION:Main electrodes 2 are sealed on both ends. An emission tube wall load is 20-100W/cm<2>. Dysprosium halide, neodium halide, cesium halide and indium halide are sealed as emission metals, and a rare gas and mercury are also sealed. The amount of sealed dysprosium halide per unit volume of an emission tube is 2.2X10<-6>mol/cc>=DyX3>=5.5X10<7>mol/cc, and that of indium halide is 2.1X10<-6>mol/cc>=InX>=4.1Xl0<-7>mol/cc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a metal halide lamp used without an outer bulb, and more particularly to a short arc metal halide lamp as a light source for video equipment or optical equipment.

[0002]

2. Description of the Related Art Conventionally, a short arc metal halide lamp, which is used only by an arc tube without using an outer tube, has been used as a light source for an overhead projector (OHP) or a projector. This metal halide lamp is required to have a luminescent metal that is relatively close to the color temperature of a television cathode-ray tube and has a well-balanced emission in the entire visible wavelength range due to its application, and dysprosium and neodymium are used. Has been done. However, although these luminescent metals have a well-balanced luminescence in the entire visible wavelength range, considering the luminosity factor, the green component becomes strong due to the mercury peak in the green range, and a sufficiently satisfactory luminescence balance cannot be obtained yet.

Therefore, a method of raising the luminous metal to a desired vapor pressure by means such as increasing the wall load of the arc tube is adopted. However, quartz glass and metal halide which are materials of the arc tube generated by increasing the wall load. The devitrification phenomenon caused by the reaction with is unavoidable, which causes an inconvenience that the brightness is deteriorated at an early stage.

[0004]

DISCLOSURE OF THE INVENTION The present invention has been made in view of the above, and the type and the amount of the light emitting metal of the short arc metal halide lamp used only in the light emitting tube without using the outer tube are set within a certain range. By defining, it is possible to provide a well-balanced light emission in the entire visible wavelength range, improve the color temperature, and prevent the deterioration of brightness that occurs at an early stage, and provide the optimal lamp as a light source for video equipment. The purpose is to do.

[0005]

According to the present invention, an outer tube is not provided and only an arc tube is provided. At least main electrodes are sealed at both ends, and the wall surface load of the arc tube is 20 to 100 W / cm ² . Dysprosium halide (DyX ₃ ) as a light emitting metal,
In a short arc metal halide lamp in which neodymium halide (NdX ₃ ), cesium halide (CsX) and indium halide (InX) are enclosed and a rare gas as a starting auxiliary gas and mercury as a buffer gas are enclosed, an arc tube is provided. The amount of dysprosium halide (DyX ₃ ) per unit volume is 2.2 × 10 ^-6 mol / c
c ≧ DyX ₃ ≧ 5.5 × 10 ⁻⁷ mol / cc, and the amount of indium halide (InX) is 2.1 × 10 ⁻⁶ mol / cc
It is characterized by encapsulating in the range of cc ≧ InX ≧ 4.1 × 10 ⁻⁷ mol / cc. Further, it is characterized in that a reflecting mirror having a spherical surface, a spheroidal surface, a paraboloid of revolution, or a combination thereof is used integrally or in combination at one end of the arc tube. Further, when the maximum inner diameter of the arc tube is d and the distance between the electrodes is 1, l / d is 1.0 or less.

[0006]

With the above structure, a well-balanced light emission is obtained over the entire visible range, and the emission color does not change throughout the life. Also, a lamp with a reflecting mirror having good light distribution characteristics can be obtained. Furthermore, a compact metal halide lamp with excellent life characteristics can be obtained.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a side view of a short arc metal halide lamp. In Fig. 1, reference numeral 1 is a quartz glass arc tube tare, which has a substantially spherical shape with a maximum inner diameter of 9 cm, a maximum outer diameter of 11 cm and an internal volume of about 0.5 cm ³ . . Reference numeral 2 is an electrode that is connected via the molybdenum foil 4 at both end sealing portions 3 of the arc tube tare 1. The distance between both electrodes is set to 5 mm. Reference numeral 5 is an external lead wire made of molybdenum connected to the molybdenum foil 4, and 6 is an exhaust pipe tip-off portion.

A predetermined amount of dysprosium iodide, neodymium iodide, cesium iodide and indium iodide is enclosed as a light emitting metal in such an arc tube, and a predetermined amount of mercury as a buffer gas is further added. Argon gas of about 2.7 × 10 ⁴ Pa is enclosed as an auxiliary gas. Then, the wall load is set to about 60 W / cm ² , and the electronic ballast is used by AC lighting of 150 W of lamp power.

Experimental examples will be described below. First, as shown in Table 1, lamps having a constant amount of light emitting metal other than indium iodide and different indium iodide amounts were manufactured, and the light emitting characteristics thereof were confirmed.

[Table 1] (Note) DyI ₃ + NdI ₃ + CsI: 0.6 mg Unit: mol / cc Then, the luminous flux and the emission spectrum of each experimental example were measured,
The relative value of the spectral intensity, the blue / green range (B / G), and the red / green range (R / G) were obtained and comparatively examined. The results are shown in Table 2. (However, B: 410-50
0 nm G: 500 to 570 nm R: 580 to 780
nm wavelength range)

[Below margin]

[0010]

[Table 2] As shown in Table 2, as the amount of indium iodide is increased, the R, G, B emission intensity balance is improved. (Especially B
/ G), but the luminous flux drops sharply. This is because Hg peak intensity (5
(46 nm, etc.), the color balance is improved, and the luminous flux is reduced.

Next, when these lamps were set on a reflecting mirror and projected on a 40-inch screen, an experiment was conducted to see if the same brightness as the conventional lamp could be obtained.
In C and D, although the same brightness as the conventional lamp was obtained,
In E and F (2.9 × 10 ⁻⁶ mol / CC), both the maximum illuminance and the average illuminance are lower than those of the conventional lamp, and the light is dark.
Further, with the amount of indium iodide of lamp A (8.2 × 10 ⁻⁸ mol / cc), the lamp (R
There is no change from f) and there is no effect of encapsulating indium iodide. This is because the screen illuminance can be adjusted depending on the setting condition of the reflecting mirror, the characteristics of the reflecting film of the reflecting mirror, its shape, etc. if the luminous flux is reduced to the extent shown by the lamp D (about 13%). ) Is enclosed in the range of 2.1 × 10 ⁻⁶ mol / CC ≧ InX ≧ 4.1 × 10 ⁻⁷ mol / CC, a lamp having a good color balance can be obtained without significantly reducing the brightness.

Next, a certain amount of neodymium iodide was added to the arc tube.
Lamps containing cesium iodide and indium iodide and having different amounts of dysprosium iodide as shown in Table 3 were prepared and their characteristics were confirmed. The results are shown in Table 4.

[Table 3]

[0013]

[Table 4] As is clear from Table 4, as the amount of dysprosium iodide is increased, the R, G, B emission balance is improved, the color characteristics are improved, and the ideal color balance is obtained. It should be noted that in order to have a good color balance, it is necessary to consider the human visibility in consideration of the usage of the lamp, but in this experiment, the relative comparison of each lamp is made, so the visibility has not been corrected. Absent.

Further, when the lamp was tested in a horizontal position for lighting, after 1000 hours, the quartz glass, which is the material of the arc tube, and the metal halide react with each other to cause the devitrification phenomenon of quartz. It can be seen that it becomes remarkable as the amount of dysprosium increases, and has a great influence on the deterioration of brightness.

[Table 5] (Note) 40-inch screen characteristics change, 0 hours to 10
Converted as 0. Average illuminance: average of center brightness obtained by dividing 40 inches into 9 parts As shown in Table 5, after 1000 hours of lighting, 2.8 × 1
If the amount of dysprosium iodide is larger than 0 ^-6 mol / cc, the maintenance factor of brightness becomes poor. This is because in the lamps A to D, the devitrification phenomenon of the quartz glass of the arc tube is only the reaction with dysprosium at the highest temperature portion that usually occurs in the lamps. , F, the unevaporated dysprosium reacts in a liquid state in the lower part of the lamp to cause devitrification. Also, 2.
When the amount of dysprosium iodide is about 8 × 10 ⁻⁷ mol / cc, the intensity of the green region (G) of the emission spectrum is strong and the color balance is not good. It should be noted that the criterion for the color balance is B in Table 4 because the human visual sensitivity has its peak in the green region.
The standard is that / G and R / G are both 1.5 or more.

Thus, from Experiment 2, the amount of dysprosium iodide was 2.2 × 10 ⁻⁶ mol / CC ≧ DyX ₃ ≧ 5.5.
By encapsulating in the range of × 10 ^-7 mol / CC, it is possible to obtain a lamp with good color balance and little decrease in brightness.
According to the results of the above experiments, the amount of indium iodide in the luminous metal sealed in the arc tube was 2.1 × 10 ⁻⁶ mol / C.
C ≧ InX ≧ 4.1 × 10 ⁻⁷ mol / CC, the amount of dysprosium iodide is 2.2 × 10 ⁻⁶ mol / CC ≧ DyX ₃ ≧
By selecting in the range of 5.5 × 10 ⁻⁷ mol / CC, a lamp having good emission characteristics and little deterioration in brightness can be obtained.

Although metal iodide has been described in the above embodiments, substantially the same effect can be observed for metal halides such as bromide. Further, when the short arc metal halide lamp according to the present invention is used as a light source for video equipment, one end of a sealing portion of an arc tube is fixed to the bottom of a reflecting mirror having a spherical surface, a spheroidal surface, a paraboloid of rotation, or a combination thereof. It is configured as a short arc metal halide lamp device and functions as a backlight for a liquid crystal panel. Further, when the maximum inner diameter of the arc tube is d and the distance between the electrodes is 1, 1 / d is set to 1.0 or less, and the distance between the electrodes is preferably 3 to 5 mm. On the other hand, if it exceeds 1.0, the converging efficiency of the reflecting mirror is lowered and sufficient brightness cannot be obtained. Therefore, it is desirable to select within this range.

[0017]

As is apparent from the above description, indium halide is used as a metal to be sealed in the arc tube.
1 × 10 ⁻⁶ mol / CC ≧ InX ≧ 4.1 × 10 ⁻⁷ mol / CC, dysprosium halide is 2.2 × 10 ⁻⁶
By encapsulating in the range of mol / CC ≧ DyX ₃ ≧ 5.5 × 10 ⁻⁷ mol / CC, a well-balanced light emission is obtained over the entire visible wavelength range of the lamp, and the color temperature is improved, and at an early stage. It is possible to prevent the deterioration of brightness that occurs and obtain an optimum lamp as a light source for video equipment.

[Brief description of drawings]

FIG. 1 is a side view showing an arc tube according to the present invention.

[Explanation of symbols]

 1 arc tube 2 electrode 3 sealing part 4 molybdenum foil 5 external lead wire 6 chip-off part

Claims (3)

[Claims] 1. An outer tube is not provided and only an arc tube is provided. At least main electrodes are sealed at both ends, and a wall load of the arc tube is 2 or less.
It is 0 to 100 W / cm ² , and dysprosium halide (DyX ₃ ), neodymium halide (NdX ₃ ), cesium halide (CsX) and indium halide (InX) are enclosed as light emitting metals, and In a short arc metal halide lamp in which a rare gas as a starting auxiliary gas and mercury as a buffer gas are enclosed, the amount of dysprosium halide (DyX ₃ ) is 2.2 × 10 ⁻⁶ mol / unit volume of the arc tube. cc ≧ DyX ₃ ≧ 5.5 × 10
^-7 mol / cc and indium halide (InX)
The amount of 2.1 × 10 ⁻⁶ mol / cc ≧ InX ≧ 4.1 × 10
A short arc metal halide lamp characterized by being enclosed in a range of ^-7 mol / cc. 2. The short circuit according to claim 1, wherein a reflecting mirror having a spherical surface, a spheroidal surface, a paraboloid of revolution, or a combination thereof is used integrally or in combination at one end of the arc tube. Arc metal halide lamp. 3. The maximum inner diameter of the arc tube is d, and the distance between electrodes is 1
The short arc metal halide lamp according to claim 1 or 2, wherein 1 / d is 1.0 or less.