JP3132042B2 - Metal halide lamp - Google Patents

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 which is constituted only by an arc tube without an outer tube and is used together with a liquid crystal panel having a polarizing plate.

[0002]

2. Description of the Related Art Conventionally, small metal halide lamps which are used only with an arc tube without providing an outer tube have been used gradually in overhead projectors (OHP), projectors and the like, and are gradually spreading. In recent years, it has been widely used as a light source for video equipment using liquid crystal. In such a small metal halide lamp, the wall load of an arc tube in which a metal halide having a low vapor pressure is sealed is increased, thereby increasing the vapor pressure of the metal halide to obtain a desired light emission.

As such a metal halide lamp, the present inventor has previously disclosed in Japanese Patent Application No. 2-106348, neodymium halide, dysprosium halide, iodine or bromine or a mixture thereof containing halogen as an encapsulating material for an arc tube. Select a cesium halide and set an appropriate encapsulation ratio and encapsulation amount. Even if there is some variation in input power or encapsulation amount in a relatively large arc tube, it can be used as a light source for OHP TVs. We have proposed a metal halide lamp that has chromaticity coordinates close to a suitable blackbody locus, can reduce the tube wall load, has a long service life, and has good spectral characteristics.

[0004]

By the way, the metal halide lamp proposed above has a black body locus B. as shown by a in the x, y chromaticity diagram of FIG. Chromaticity coordinates approximate to L (0.
314, 0.325) and good color characteristics. However, when such a metal halide lamp is used as a light source for an optical imaging device using a liquid crystal panel, the liquid crystal panel is provided with a polarizing plate that allows more light to pass through a green area for shading and transmitting light. Even if the chromaticity coordinates are good, the chromaticity coordinates on the screen move to the upper right as shown in FIG. 4B by passing through the liquid crystal panel provided with the polarizing plate. Therefore, there is a problem that the color reproducibility changes due to the shift of the chromaticity coordinates. The size of the liquid crystal panel is 2
It is about 3 inches, and there is a problem that the screen illuminance cannot be so bright due to the difficulty of condensing light on such a small-area liquid crystal panel.

The present invention has been made to solve the above-mentioned problem when such a metal halide lamp is used together with a liquid crystal panel having a polarizing plate. It is an object of the present invention to provide a metal halide lamp that can obtain chromaticity coordinates close to a blackbody locus, has excellent color reproducibility, and can easily collect light.

[0006]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a liquid crystal panel comprising only an arc tube without an outer tube and having a polarizing plate which passes through a green region more than others. When the lamp power is P (W) and the arc tube internal volume is V (cc), V is 1 cc or less and the range is 300 ≦ P / V ≦ 3000 (W / cc). The metal halide to be set and enclosed includes at least dysprosium halide (DyX ₃ ), neodymium halide (NdX ₃ ), and cesium halide (CsX), and the total amount of these metal halides is defined as T (mg). Then, the lamp power P (W) is set in the range of 2.5 × 10 ⁻³ ≦ T / P ≦ 1.3 × 10 ⁻² (mg / W), and the metal halide is In the ratio, 0.05 ≦ NdX ₃ / DyX ₃ ≦ 0.2, 1 ≦ (Nd X ₃ + DyX ₃ ) /CsX≦2.5, and the total molar inclusion amount is 3 × 10 ⁻⁶ to 4 × 10 ^−5.
Mol / cc, and a rare gas as a starting auxiliary gas,
Mercury is sealed as a buffer gas.

With this configuration, a metal halide lamp having chromaticity coordinates located below the locus of the black body can be obtained, and the emitted light is passed through a liquid crystal panel having a polarizing plate that transmits more green light than others. As a result, the chromaticity coordinates of the light move to the upper right, and a desired light source color having chromaticity coordinates close to the locus of the black body is obtained on the screen. In addition, by reducing the size of the arc tube, focusing becomes easier,
A desired screen illuminance can be easily obtained.

[0008]

Next, an embodiment will be described. FIG. 1 is a view showing an embodiment of a metal halide lamp according to the present invention. In the drawing, 1 is a quartz discharge vessel of a metal halide lamp with a rated power of 150 W, with a maximum outer diameter of 8.5 mm and a maximum inner diameter.
It has a thickness of 4.7 mm, an inner volume of 0.1 cc, a shape approximating a spheroid, and a thick wall. Reference numerals 2 denote electrodes attached to the molybdenum foil 4 at the sealing portions 3 at both ends of the discharge vessel 1, and the gap between the electrodes is set to 3 mm. Reference numeral 5 denotes a molybdenum external lead wire connected to the molybdenum foil 4, and reference numeral 6 denotes an exhaust pipe tip-off portion.

In this embodiment, DyI ₃ and CsI at a molar ratio of 1: 1.2 are introduced into the arc tube thus constituted.
0.9 mg and NdI ₃ and Cs, also in a molar ratio of 1: 1.2
I is filled with 0.2 mg, and argon as a starting auxiliary gas and 6 mg of mercury as a buffer gas.

Since the metal halide lamp thus configured has a small internal volume of the arc tube, the light emission size of the light source is small, light is easily collected, and the wall load is relatively large. The deformation of the arc tube due to the large wall load is prevented by cooling the center of the highest temperature portion by a blowing means or the like, and by making the arc tube wall thick as described above. .

Since the volume inside the arc tube is reduced and the tube wall load is increased as described above, the chromaticity coordinates of the metal halide lamp itself are represented by the black body locus B as shown in the chromaticity diagram of FIG. . By passing through a liquid crystal panel which is located below L and has a polarizing plate that allows the green area to pass through more than the others, chromaticity coordinates on a substantially blackbody locus can be obtained.

According to the present invention, the inner volume V of the arc tube is set to 1 cc or less, and the lamp power P and the inner volume V are set to 300 ≦ P / V ≦
3000 (W / cc), and the total amount T of metal halide to be enclosed and the lamp power P are set to 2.5 × 10 ⁻³ ≦ T /
P ≦ 1.3 × 10 ⁻² (mg / W) is set, and the metal halide content is 0.05 ≦ NdX ₃ / DyX ₃ ≦ 0.
2, 1 ≦ (NdX ₃ + DyX ₃ ) /CsX≦2.5, and the total molar inclusion amount is 3 × 10 ⁻⁶ to 4 × 10 ^−5.
Next, an experiment performed to set the above conditions will be described.

First, an experiment performed for setting a range of a ratio P / V between the lamp power P and the arc tube inner volume V will be described. When the wall load was less than 300 W / cc using an arc tube having the same size as that of the above embodiment, the chromaticity coordinates were as shown in FIG. Although located below L, the color rendering properties were degraded and the color temperature was too high, that is, the atomic emission of dysprosium iodide DyI ₃ was too large to fall within the desired light source color range. On the other hand, when the wall surface load exceeds 3000 W / cc, the color temperature decreases and the chromaticity coordinates also change as shown in FIG. L
It has been found that the chromaticity coordinates are distributed more upward than the desired chromaticity coordinates of the present invention. Therefore, the ratio P / V of the lamp power P to the arc tube inner volume V is 300 to 3000 (W /
cc).

Next, a description will be given of an experiment conducted when the inner volume V of the arc tube is set to 1 cc or less. Set the internal volume V to 1.
When an arc tube with 5 cc was made and a lighting experiment was performed, the apparent luminous volume was increased due to devitrification of the arc tube by DyI ₃ , and the optical utilization factor was deteriorated, so that it was inconvenient to use the device. It was confirmed that there was. Therefore, in the present invention, the inner volume of the arc tube is specified to be 1 cc or less.

In setting the range of the ratio T / P between the total amount T of the metal halide and the lamp power P, the following experiment was conducted. In other _{words, (NdI 3 + DyI 3)} / CsI
= 1.1, DyI ₃ / NdI ₃ = 10, and the life test was performed by changing the lamp power P while keeping the inner volume of the arc tube constant.
If the ratio T / P is less than 2.5 × 10 ⁻³ mg / W, the light source color is certainly located on the x, y chromaticity diagram below the blackbody locus, for example, T / P = 2. At 0 × 10 ⁻³ mg / W, the chromaticity coordinates are (0.26, 0.27), the color temperature is too high, and the color rendering properties are also _Ra.
= 68, which was inferior and a good light source could not be obtained. This only lowers the vapor pressure of the iodide dysprosium DyI _3, as a result, although atomic emission of Dy emits blue region, it is because the main, desired color rendition and chromaticity coordinates obtained Can not be. Further, when T / P exceeds 1.3 × 10 ^-2 mg / W, for example, at 1.5 × 10 ^-2 mg / W, the chromaticity coordinates become (0.35, 0.
37) and fluctuates upward from the blackbody locus. This is because when the amount of metal iodide is increased, the vapor pressure of neodymium iodide NdI ₃ becomes too high, and the green region, which is the molecular emission of neodymium iodide, increases. Therefore, appropriate T /
The range of P is 2.5 × 10 ⁻³ ≦ T / P ≦ 1.3 × 10 ⁻² (mg /
W).

Next, an experiment performed for setting the molar ratio of NdX ₃ / DyX ₃ will be described. Using an arc tube of the same size as the above embodiment, (NdI ₃ + DyI ₃ ) / CsI =
Was constant at 1.1, the NdI ₃ / DyI _3, 2,1,0.3,
Set 0.2,0.1,0.05,0.03 create Encapsulated lamp was lit, the chromaticity coordinates of the lamp itself is a C ₁ in the chromaticity diagram of FIG. _{3, C 2, C 3,} C _4, C _5, C _6,
It changes as shown by C _7, the molar ratio 2,1,0.3,0.03
Is the blackbody locus B. It was distributed along L or above the blackbody locus, and the desired chromaticity coordinates below the blackbody locus could not be obtained. Even if the amount of NdI ₃ is reduced, the total vapor pressure does not increase and the emission of Hg (546 nm) is strong.
The light source color results in being located above the blackbody locus.
Accordingly suitable NdI ₃ / DyI ₃ is used for setting the range of 0.05 to 0.2.

Next, an experiment performed for setting the molar ratio of (NdX ₃ + DyX ₃ ) / CsX will be described. Similarly, using an arc tube having the same size as that of the above embodiment, (NdI ₃ + DyI
A lamp was prepared in which the amount of CsI was varied with the amount of ₃ ) kept constant, and color characteristics and luminous efficiency were measured. The following results were obtained. First, (NdI ₃ + DyI
₃ ) If / CsI exceeds 2.5, the luminous efficiency is reduced to 60 lm / W or less, and the vapor pressure is increased, but the arc is thin and the arc fluctuates, causing a problem in practical use. If the above ratio is less than 1, the desired vapor pressure cannot be obtained, the atomic emission of dysprosium becomes dominant, the color temperature becomes too high, and the luminous efficiency becomes 60 lm / W or less, and the predetermined efficiency is obtained. I couldn't. Thus _{(NdI 3 + DyI 3) /} Cs
The molar ratio of I is set in the range of 1 to 2.5.

Next, a description will be given of an experiment conducted on the total amount of these metal halides. Similarly, when a life test was performed on an arc tube having the same size as that of the above-described embodiment while changing the total amount of the metal halide, the total amount of the metal halide was 3 ×
If it is less than 10 ^-6 mol / cc, within 300 hours during the lighting operation, both the blue region of the atomic emission of dysprosium and the red region of the molecular emission decrease, and the chromaticity coordinates indicate the black body locus B. There is a problem that it is largely deviated above L. Also, if the total amount exceeds 4 × 10 ^-5 mol / cc, the color of the un-evaporated encapsulant will come on and cause color unevenness. After all, it moves to the upper part of the black body locus. Therefore, the total amount of the metal halide is set in the range of 3 × 10 ⁻⁶ to 4 × 10 ⁻⁵ mol / cc.

The chromaticity coordinates of the metal halide lamp according to the present invention prepared according to the conditions set on the basis of the results of the above experiments are located within the range indicated by the chromaticity diagram in FIG. High efficiency and long life were confirmed.

In the above embodiment, the metal halide (NdI ₃ , DyI ₃ , CsI) containing iodine as the halogen is encapsulated, but the halogen is bromine or a mixture of iodine and bromine. Even when enclosed,
It was confirmed that the same effects were obtained under the same conditions.

[0021]

As described above with reference to the embodiments,
According to the present invention, by setting an appropriate internal volume of the arc tube and an appropriate ratio between the arc tube and the lamp power, and an appropriate encapsulation ratio and an encapsulation amount of the encapsulating metal halide, a position below the blackbody locus can be obtained. A lamp having the following chromaticity coordinates,
By passing the light through a liquid crystal panel having a polarizing plate that allows the green region to pass more than the others, it is possible to obtain a desired light source color having chromaticity coordinates close to the locus of a black body on the screen. Further, since the arc tube size is small, light collection becomes easy, and a desired screen illuminance can be easily obtained.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a change in chromaticity coordinates when the chromaticity coordinates and the wall load on the x, y chromaticity diagram of the embodiment of the present invention are changed.

3 is a diagram showing a variation of the chromaticity coordinates in the case of changing the enclosed molar ratio of NdI ₃ / DyI _3.

FIG. 4 is a diagram showing a change in chromaticity coordinates on a screen when a liquid crystal panel having a polarizing plate is passed through a conventional metal halide lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Discharge container 2 Electrode 3 Sealing part 4 Molybdenum foil 5 External lead wire

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01J 61/20 H01J 61/88

Claims (1)

(57) [Claims] Claims: 1. An arc tube without an outer tube,
In a metal halide lamp used with a liquid crystal panel provided with a polarizing plate that allows the green region to pass through more than others, when the lamp power is P (W) and the arc tube internal volume is V (cc), V is 1 cc or less and 300 is set in a range of ≦ P / V ≦ 3000 (W / cc), metal halide encapsulating at least halogenated dysprosium (dyX _3), halogenated neodymium (NdX _3), wherein the cesium halide (CsX) When the total amount of these metal halides is T (mg), 2.5 × 10 ⁻³ ≦ T / P ≦ 1.3 × 10 ⁻² (mg / W) ) And the molar ratio of the metal halide is 0.05 ≦ NdX ₃ / DyX ₃ ≦ 0.2, 1 ≦ (NdX ₃ + DyX ₃ ) /CsX≦2.5. The molar encapsulation amount is 3 × 10 ^-6 to 4 × 10 ^-5
Mol / cc, and a rare gas as a starting auxiliary gas,
A metal halide lamp characterized by containing mercury as a buffer gas.