JP2006294413A - High pressure discharge lamp and image projection device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To attain long service life of a high pressure discharge lamp by suppressing scattering of a metal oxide film scattered due to seal heating. <P>SOLUTION: A pair of electrodes 151, 152 are arranged in a discharge space 14 facing each other, the electrodes 151, 152 are joined to ends of metal foils 171, 172, electric lead-in wires are joined to the other ends of the metal foils 171, 172 and sealed with sealing parts 131, 132 to keep airtightness in parts of the metal foils 171, 172. A coating film 21 made of a metal oxide film is formed at least on one side of the metal foil 171,172, and a silica film 22 covering the coating film 21 is formed. Thereby, scattering of the metal oxide film of the coating film 21 scattered due to the seal heating can be suppressed and the service life can be sufficiently prolonged by the coating film of the metal oxide film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-pressure discharge lamp used as a light source for an image projection apparatus such as a liquid crystal projector and an image projection apparatus using the same, which require a high efficiency, high output, high light collection efficiency and a compact design. .

A conventional high-pressure discharge lamp encloses a discharge medium containing mercury, halogen, rare gas, etc. in a discharge space formed inside a light-transmitting hermetic container, and seals the sealing parts formed at both ends of the hermetic container. A metal foil made of, for example, molybdenum having a tungsten electrode bonded to the end is sealed. The metal foil has a coating film formed of at least one metal oxide film selected from titanium oxide, lanthanum oxide, and tantalum oxide on at least one surface, and a sealing portion is formed near the metal foil from the coating film. Alkaline metal cations present as impurities in silica glass and halogen metal cations encapsulated as luminescent metals move and accumulate near the metal foil, but they are degraded by cations due to the coating film made of metal oxide. Is suppressed, and a long life is obtained. (For example, Patent Document 1)
JP 2003-86135 A

  The technique of the above-mentioned patent document 1 is that the metal coating film which has an effect on the long life is scattered by heating for sealing, and the metal foil surface is not satisfactorily coated after sealing, so that the metal oxide film is oxidized. There was a problem that the effect of the film could not be sufficiently obtained.

  An object of the present invention is to provide a high-pressure discharge lamp that can suppress the scattering of a metal oxide film that is scattered due to sealing heating, and can sufficiently obtain the effect of extending the life of the coating film by the metal oxide film. There is.

  In order to solve the above-described problems, a high pressure discharge lamp according to the present invention includes a discharge space having a pair of electrodes arranged opposite to each other, the electrode joined to one end of a metal foil, and the other end of the metal foil. An electric lead-in wire is joined, and has a sealing portion sealed so as to maintain airtightness at the metal foil portion, and the lighting pressure at the time of stable lighting is 40 atm or more. The metal foil is characterized in that a coating film made of a metal oxide film is formed on at least one surface, and a silica film covering the metal oxide film is formed.

  According to the present invention, it is possible to suppress the scattering of the metal oxide film that is scattered due to the sealing heating, and to obtain the effect of extending the life by the coating film of the metal oxide film.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a side view for explaining one embodiment of a high-pressure discharge lamp of the present invention. In FIG. 1, reference numeral 11 denotes a transparent quartz glass bulb, and an arcuate arc tube portion 12 and the bulb 11 formed of the same material as the arc tube portion 12 at both longitudinal ends thereof are hermetically sealed. It consists of stop portions 131 and 132. The arc tube portion 12 is formed with a substantially cylindrical discharge space 14 in the longitudinal direction thereof. The discharge space 14 is formed of, for example, a tungsten material extending from the inside of the sealing portions 131 and 132. The electrodes 151 and 152 are arranged so that their tips face each other with an interval of about 2.3 mm, for example. The shaft diameters of the electrodes 151 and 152 are φ0.4 mm, and coils 161 and 162 of φ0.2 mm are wound around one end of the electrodes 151 and 152. In the discharge space 14, for example, a discharge medium containing mercury (Hg), argon (Ar) gas, and a Dy—Nd—In—Cs metal halide is enclosed. The Hg amount is enclosed in a predetermined amount that makes the lamp voltage 60 V or more.

  The sealing portions 131 and 132 are formed by crushing, and metal foils 171 and 172 made of molybdenum (Mo) are sealed inside to keep airtight. The metal foils 171 and 172 have a thickness of 28 μm, a width of 3 mm, and a length of about 20 mm. As shown in FIG. 2, the metal foils 171 and 172 are coated with a titanium oxide film 21 having a thickness of 50 to 1000 nm, and a silica film 22 covering the titanium oxide film 21 is coated with 500 to 1200 nm.

  One end of each of the metal foils 171 and 172 is welded to the electrodes 151 and 152, and the other end is connected to molybdenum wires 181 and 182 by welding. The other end of the wire 181 is connected to a nickel wire having a thickness of about 15 μm by covering platinum with a diameter of about 0.4 mm. The other end of the wire 182 has an elliptical reflector and the vicinity of the sealing portion 131, for example, alumina. Electric power is supplied from the lighting device 19 outside the lamp via a base fixed with an adhesive.

  This discharge lamp is lit with a DC lighting type lamp power of 250 W, and has a light output of 70 to 80 lm / W, and is used for a light source for a projector, for example, in an elliptical or parabolic shape. Efficiency such that the amount of light reaching the screen exceeds 10 lm / W can be obtained. The operating pressure during lighting is designed to exceed 6 MPa.

  FIG. 3 shows a high-pressure discharge lamp in which the titanium oxide film 21 and the silica film 22 are formed on the metal foils 171 and 172, as a sample A, and a high-pressure discharge lamp when only the metal foils 171 and 172 are used as a sample B. The results are shown in the case where a life test is performed on the occurrence of leakage and breakage of 10 sample products.

  That is, when the lighting time was 2000 hours, in Sample B, the occurrence of leakage and breakage starting from the metal foils 171 and 172 was 1 in 10, and in Sample A, 0 out of 10 was obtained. Moreover, even when the lighting time was 2500 hours, Sample B had leakage / breakage starting from the metal foils 171 and 172, 3 out of 10 samples, and Sample A had 1 out of 10 results. .

  Therefore, it was confirmed that when the titanium oxide film 21 and the silica film 22 were formed on the metal foils 171 and 172, the life of the lamp could be extended.

  As described above, the titanium oxide film 21 is formed on the metal foils 171 and 172, and further the silica film 22 covering the titanium oxide film 21 is formed, thereby suppressing the scattering of the titanium oxide film 21 during the sealing heating. Can improve the service life.

FIG. 4 is an explanatory diagram for explaining the image photographing apparatus of the present invention when the high-pressure discharge lamp having the configuration shown in FIG. 1 is mounted on a liquid crystal projector.
In FIG. 4, reference numeral 31 denotes a liquid crystal projector. The liquid crystal projector 31 has a main body 32, and a projection opening 33 is formed on the front side of the main body 32. In addition, a light source 34 is disposed in the main body 32, and the light source 34 is formed by a high-pressure discharge lamp 35 and a reflector 36 as a reflecting means optically opposed to the high-pressure discharge lamp 35. A liquid crystal panel 37 as a display unit is disposed in front of the irradiation direction of the light source 34, and a projection lens 38 as a projection unit is disposed corresponding to the projection opening 33 in front of the liquid crystal panel 37. Yes. A screen 39 is disposed in front of the projection opening 33.

  Further, a lighting circuit 40 is connected to the high-pressure discharge lamp 35, a liquid crystal driving circuit 41 is connected to the liquid crystal panel 37, and a commercial AC power source 42 is connected to the lighting circuit 40 and the liquid crystal driving circuit 41. The lighting circuit 40 may be one that lights the high-pressure discharge lamp 35 with direct current or one that lights with alternating current.

  In the image capturing apparatus having the above-described configuration, first, the lighting circuit 40 lights the high-pressure discharge lamp 35 of the light source 34. The light from the high pressure discharge lamp 35 is irradiated directly or reflected by the reflector 36 toward the liquid crystal panel 37. In the liquid crystal panel 37, the display is changed by the liquid crystal driving circuit 41, and the light from the light source 34 is transmitted and projected by the projection lens 38 to display an image on the screen 39.

  As described above, in the image photographing apparatus of the present invention, the high-pressure discharge lamp of the present invention is used as a light source lamp, so that the life of the lamp can be extended, and further, the reliability of the entire liquid crystal photographing apparatus is improved. It becomes possible.

The block diagram for demonstrating one Embodiment of this invention. The expanded sectional view of the principal part of FIG. Explanatory drawing for demonstrating the effect of this invention. The system block diagram for demonstrating one Embodiment regarding the image imaging device of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Bulb 12 Light emission tube part 131,132 Sealing part 14 Discharge space 151,152 Electrode 161,162 Tungsten coil 171,172 Metal foil 181,182 Wire 19 Lighting device 21 Titanium oxide film 22 Silica film 51 Liquid crystal projector

Claims (2)

A discharge space having a pair of electrodes arranged opposite to each other, the electrode is joined to one end of a metal foil, and an electric lead-in wire is joined to the other end of the metal foil. In a discharge lamp having a sealing part sealed to maintain airtightness and having a lighting pressure of 40 atm or more during stable lighting,
A high pressure discharge lamp characterized in that a coating film made of a metal oxide film is formed on at least one surface of the metal foil, and a silica film is formed to cover the coating film. A high-pressure discharge lamp according to claim 1;
An image projection apparatus comprising: the high-pressure discharge lamp as a light source; and an image projection apparatus main body that projects an image based on light emitted from the light source.

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