JPH1092378A - High pressure mercury discharge lamp - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a high pressure mercury discharge lamp as being capable of showing emission spectrum with red, green and blue well balanced and preventing the breakage of arc tube in its lighting life. SOLUTION: A pair of tungsten electrodes 2a, 2b at a clearance of 1.5mm are provided inside a silica glass arc tube 1 which has a luminous portion 1a and sealed portions 4a, 4b ranging to both ends of the luminous portion 1a. Mercury 3 is filled in the arc tube 1 at a density of 150mg/cm<3> , and 100hPa argon gas as starting rare gas and CH2 Br2 as filler isolated during lighting to be halogen at a density of 5×10<-9> mol/cm<3> are also filled therein. CH2 Br2 as filler is decomposed during lighting a lamp so that Cl, Br and I can exist in the arc tube 1 at a density of 1×10<-8> mol/cm<3> .

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure mercury discharge lamp used for a backlight of an optical device such as a liquid crystal projector or an overhead projector.

[0002]

2. Description of the Related Art In recent years, as a backlight for optical equipment such as a liquid crystal projector and an overhead projector, a so-called short arc in which a metal halide is sealed in an arc tube, the light emission unique to the metal is used, and the distance between electrodes is reduced. A projection type light source in which a metal halide lamp of a type is combined with a reflecting mirror is used.

[0003] In recent years, a short arc has been promoted to further increase the brightness of such a metal halide lamp. However, when the distance between the electrodes becomes 3 mm or less, the emission intensity of the encapsulated mercury emission line increases, and the emission intensity of the encapsulated metal becomes relatively lower than the emission intensity of the mercury emission line. As a result, the relative emission intensity in the red region (around 610 nm) and blue region (around 450 nm) of the emission spectrum of the lamp is reduced, and the emission spectrum in which the red, green, and blue required for the backlight for the liquid crystal projector are balanced. Was not obtained.

[0004]

Further, a projection type light source in which a high-pressure mercury discharge lamp in which continuous light emission in the visible region is increased by increasing the vapor pressure of mercury during operation from 20 MPa to 35 MPa and a reflecting mirror is used. Is known (JP-A-2-148561). However, such a high-pressure mercury discharge lamp can increase the continuous emission in the visible region and obtain a balanced emission spectrum of red, green, and blue. The probability of breakage increases.

According to the present invention, it is possible to obtain a balanced emission spectrum of red, green, and blue required for a backlight for a liquid crystal projector, and to reduce the probability that an arc tube is damaged during a lighting life. The object is to obtain a high-pressure mercury discharge lamp that can be used.

[0006]

According to a first aspect of the present invention, there is provided a high-pressure mercury discharge lamp according to the first aspect of the invention. , I and 100 mg / cm ³ to 19 per unit volume of the arc tube.
It has a configuration in which mercury is sealed in the range of 5 mg / cm ³ , and the mercury vapor pressure during lighting is 10 MPa to 19 MPa.
, A light emission spectrum in which red, green, and blue are well balanced can be obtained, and the function of suppressing the probability of breakage during lighting can be obtained.

A high pressure mercury discharge lamp according to a fifth aspect of the present invention is the high pressure mercury discharge lamp according to the first aspect, wherein the free halogen Cl, Br, I contains 10 ^-9 to 10 ^-7 m in the arc tube.
ol / cm ³ , and tungsten, which is an electrode material evaporated during lamp operation, returns to the electrode without being blackened on the inner wall of the arc tube by a halogen cycle, and during the operation life of the lamp. Prevents arc tube blackening. As a result, the arc tube has a function of preventing the arc tube wall temperature from rising due to blackening of the arc tube and preventing the arc tube from being damaged during the lighting life.

[0008] A high pressure mercury discharge lamp according to a sixth aspect of the present invention is the high pressure mercury discharge lamp according to the first aspect, wherein the electrode tube distance is 3.0 mm or less, and the balance of red, blue and green is maintained. It has the function of realizing high luminance at the same time as obtaining a good emission spectrum.

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows a high-pressure mercury discharge lamp with a lighting power of 150 W according to an embodiment of the present invention, which is made of quartz glass having a light emitting portion 1a and sealing portions 4a and 4b provided at both ends of the light emitting portion 1a. Inside the arc tube 1, a pair of electrodes 2a and 2b made of tungsten are provided with a distance between the electrodes of 1.5 mm. Further, mercury 3 is sealed in the arc tube 1 at a density of 150 mg / cm ³ , argon gas is used as a starting rare gas at 100 hPa, and CH ₂ Br _{2 is} used as a sealed material which is released during lighting operation and becomes halogen. Is 5 × 1
Each is sealed at a density of 0 ^-9 mol / cm ³ .

CH ₂ Br _2, which is an enclosure, is decomposed during the operation of lighting the lamp, and Cl, Br, and I are contained in the arc tube 1 at a concentration of 1 × 10 2.
It will be present at a density of ^-8 mol / cm ^3. Also,
Metal foils 5a and 5b made of molybdenum connected to the electrodes 2a and 2b are hermetically sealed to the sealing portions 4a and 4b so that the electrodes 2a and 2b are located in the light emitting portion 1a.
One ends of the external conductors 6a, 6b are connected to the metal foils 5a, 5b, respectively, and the other ends of the external conductors 6a, 6b are led out of the arc tube 1.

The high-pressure mercury discharge lamp of the present embodiment (hereinafter referred to as the present invention) has a spectral spectrum and a distance between the electrodes of 3 mm when the lamp is operated at a lighting power of 150 W.
FIG. 2 shows spectral spectra of a conventional 250 W metal halide lamp (hereinafter, referred to as a conventional product) in which Dy-Nd-In-Cs is sealed as a fill. In FIG. 2, the product of the present invention is indicated by a solid line, and the conventional product is indicated by a broken line.

As shown in FIG. 2, when the distance between the electrodes is 3 mm, the conventional product is red (600 nm to 625 nm) and blue (435 nm to 4 nm) with respect to green (535 nm to 565 nm).
65 nm), the distance between the electrodes is 1.5 m in the product of the present invention, as compared with the case where the emission intensity of
red (600 nm to 625 nm), green (535 nm to 565 nm), and blue (435 nm to 465) despite m.
It can be seen that the emission intensity balance of (nm) is good.

Investigation of the amount of mercury enclosed revealed that if more than 100 mg / cm ³ of mercury per unit volume of the arc tube is enclosed in the arc tube, a better emission spectrum can be obtained as compared with conventional products. found.

Next, 75 mg per unit volume of the arc tube 1
Table 1 shows the results of a trial production of a lamp in which the amount of mercury was sealed from / cm ³ to 230 mg / cm ³ and a lighting life test up to 2000 hours. Table 1 also shows the balance of the light emission intensity. ○ indicates that it is preferable, and X indicates that it is not preferable.

[0016]

[Table 1]

As shown in Table 1, mercury was 100 mg / c.
The lamp sealed from m ³ to 195 mg / cm ³ is 200
The lamp did not break until 0 hours, but 75 mg of mercury
/ Cm ³ does not cause damage during the life of the lamp, but the emission intensity balance is not favorable. Further, it was confirmed that the lamp with 205 mg / cm ^{3 of} mercury had a good emission intensity balance, but one out of ten lamps was damaged, and the lamp with 230 mg / cm ^{3 of} mercury also had a light emission intensity. Balance was good but 1
It was confirmed that three of the 0 pieces were damaged. When the vapor pressure of mercury becomes 20 MPa or more,
It was confirmed that the probability that the arc tube was damaged was increased.

[0018] From these results, in order to suppress damage in life was found to be effective to encapsulate the mercury in the range of unit volume per 100 mg / cm ³ of arc tube 195 mg / cm ^3.

In addition, as a result of a lighting life test of a lamp in which only the mercury is sealed in the arc tube 1 shown in FIG. Blackening occurred due to adhesion to the inner wall of the tube. On the other hand, as a result of a lighting life test of a lamp in which halogen Cl, Br, I was sealed in a range of 10 ⁻¹⁰ to 10 ⁻³ mol / cm ³ , almost no blackening was observed within 100 hours of lighting. No remarkable blackening occurred even with a lamp lit up to 3000 hours, but halogen Cl, B
Lamps containing r and I in the range of 10 ^-9 to 10 ^-7 mol / cm ³ showed particularly good results. This is because the tungsten, which is an electrode material evaporated from the electrode during the operation of the lamp, returns to the electrode without being attached to the inner wall of the arc tube due to a halogen cycle, thereby suppressing blackening of the inner wall of the arc tube. Of the halogen Cl, Br, I, in particular, Br
This was effective in suppressing the blackening of the arc tube inner wall.

Further, in the high-pressure mercury discharge lamp of the above embodiment, CH ₂ Cl ₂ , CH ₂ is used instead of CH ₂ Br _2.
2 I ₂ , CH ₃ Cl, CH ₃ Br, CH ₃ I, CHCl ₃ , C
The same effect can be obtained by using any one of HBr ₃ and CHI ₃ .

[0021]

As described above, the high-pressure mercury discharge lamp of the present invention can provide a high-luminance, balanced emission spectrum of red, green, and blue, and can damage the arc tube during its operating life. Can be suppressed.

[Brief description of the drawings]

FIG. 1 is a front view of a high-pressure mercury discharge lamp according to an embodiment of the present invention.

FIG. 2 is a diagram showing a comparison of spectral spectra between a high-pressure mercury discharge lamp according to an embodiment of the present invention and a conventional metal halide lamp.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Arc tube 1a Light emitting part 2a, 2b Electrode 3 Mercury 4a, 4b Sealing part 5a, 5b Metal foil 6a, 6b External conductor

Claims (6)

[Claims] 1. An arc tube having a pair of electrodes provided therein contains a free halogen C during a lighting operation together with a starting rare gas.
l, Br, and I are sealed, and 100 to 195 mg / cm ³ per unit volume of the arc tube.
A high-pressure mercury discharge lamp in which mercury is sealed in a range of cm ³ . 2. The method according to claim 1, wherein said filling material is CH ₂ Cl ₂ or CH ₂ B.
high-pressure mercury discharge lamp according to claim 1, characterized in that the r ₂ or CH ₂ I _2. 3. The method according to claim 1, wherein the filling is CH ₃ Cl or CH ₃ Br.
2. The high-pressure mercury discharge lamp according to claim 1, wherein the lamp is CH ₃ I. 4. The method according to claim 1, wherein the filling is CHCl ₃ or CHBr _3.
Or high pressure mercury discharge lamp according to claim 1, characterized in that the CHI _3. 5. The free halogen Cl, Br, I emits light.
10 in the tube^-9From 10 ^-7mol / cm^ThreeExists in the range
The high pressure according to any one of claims 1 to 4, wherein
Mercury discharge lamp. 6. The high-pressure mercury discharge lamp according to claim 1, wherein a distance between the electrodes is 3.0 mm or less.