JP4058899B2 - Light source device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light source device used in a video irradiation device such as a liquid crystal projector.
[0002]
[Prior art]
For example, as a light source device for a liquid crystal projector, a combination of a short arc type discharge lamp and a concave reflecting mirror is used. However, since a liquid crystal projector is required to have a light source with good color rendering properties, A metal halide lamp in which mercury, a rare gas, and a metal halide are enclosed in an arc tube made of quartz glass with the electrodes facing each other has been used. Recently, however, an ultra-high pressure discharge lamp having an extremely high mercury vapor pressure is often used instead of a metal halide lamp. This is to increase the mercury vapor pressure, thereby suppressing the spread of the arc and further improving the color rendering and light output.
[0003]
The concave reflecting mirror is generally formed of borosilicate glass having high heat resistance, but may be formed of crystallized glass when higher heat resistance is required. A support tube portion for holding the discharge lamp is formed on the top of the back surface of the concave reflecting mirror. On the other hand, a sealing tube part is integrally provided at both ends of the arc tube of the discharge lamp, and a base is attached to the sealing tube part. The sealing tube portion of the discharge lamp is inserted into the support tube portion of the concave reflecting mirror, and an adhesive is filled between the inner peripheral surface of the support tube portion and the base and bonded.
[0004]
Recently, due to the demand for miniaturization and high output of the liquid crystal projector device, the concave reflecting mirror is miniaturized and a discharge lamp having a large output is used. Therefore, the discharge lamp becomes extremely hot, and it becomes necessary to guide the cooling air into the concave reflecting mirror to cool the discharge lamp. In particular, molybdenum foil is embedded in the sealing tube portion connected to the arc tube, but when the temperature of the sealing tube portion is high, the molybdenum foil is oxidized at a high temperature, resulting in poor electrical connection, Lamp life is significantly shortened.
However, as described above, since the sealing tube portion of the discharge lamp is inserted into the support tube portion of the concave reflecting mirror and bonded with an adhesive, the support tube portion is closed and the concave reflection is performed. The lamp cooling air blown from the opening side of the mirror cannot flow out in the direction of the back surface of the concave reflecting mirror through the inside of the support cylinder, and therefore the lamp cooling becomes insufficient, and is inserted into the support cylinder. Insufficient cooling of the sealed tube portion will cause a reduction in lamp life.
Moreover, if the cooling air vent is directly provided in the concave reflecting mirror, sink marks are generated on the reflecting surface of the concave reflecting mirror and the reflection characteristics are distorted.
[0005]
In this way, if the discharge lamp and the concave reflecting mirror are directly connected with an adhesive, the lamp cooling air cannot flow out from the support tube portion of the concave reflecting mirror. Therefore, as shown in FIG. The mirror 20 is connected via a reflector base 30 provided with a vent hole 32, and the lamp cooling air flowing in from the direction of the opening 23 of the concave reflecting mirror 20 passes through the vent hole 32 toward the back side of the concave reflecting mirror 20. May cause it to flow.
[0006]
[Problems to be solved by the invention]
In FIG. 5, the reflector base 30 is formed of ceramics in a substantially bottomed cylindrical shape, has a vent hole 32 on the back surface 33, and a small diameter portion 31 protrudes from the back surface 33. And the opening edge 30a of the reflector base 30 is adhere | attached on the back surface of the concave reflective mirror with the adhesive agent P. FIG. On the other hand, a metal base 13 is attached to one sealing tube portion 12 of the discharge lamp 10, and this portion is inserted into a small diameter portion 31 of the reflector base 30 and bonded with an adhesive P.
[0007]
Thus, since the reflector base 30 is made of ceramics, it is necessary to attach the reflector base 30 and the discharge lamp 10 with the adhesive P after attaching the metal base 13 to one sealing tube portion 12 of the discharge lamp 10. There is. That is, the base 13 is required and the number of parts increases, and a large number of man-hours are required for mounting the base 13.
[0008]
In addition, the adhesive P also becomes hot during lighting, and impurities contained in the adhesive P evaporate and adhere to the reflecting surface 22 of the concave reflecting mirror 20, so that there is a problem that the reflection efficiency is lowered and the illuminance is insufficient. Furthermore, the adhesive P itself repeatedly expands and contracts as the lamp blinks. As a result, a gap is formed on the adhesive surface, resulting in deterioration of the adhesive strength. For this reason, when a vibration or impact is applied, the discharge lamp 10 is displaced from a predetermined position, resulting in extreme illuminance deterioration. In an extreme case, the discharge lamp 10 may fall off.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to provide a light source device that can connect a discharge lamp and a reflector base without using an adhesive, has a small number of components, and can sufficiently cool the discharge lamp.
[0010]
[Means for Solving the Problems]
In order to achieve such an object, the invention of claim 1 includes a short arc type discharge lamp in which sealing tube portions are continuously provided at both ends of an arc tube made of quartz glass in which a pair of electrodes are opposed to each other. In a light source device in which a concave reflecting mirror surrounding this discharge lamp is connected via a reflector base, the reflector base is made of glass, and this reflector base is welded to one sealing tube portion of the discharge lamp. Is fixed to the back surface of the concave reflecting mirror.
[0011]
Next, the invention according to claim 2 fixes the opening edge of the reflector base to the back surface of the concave reflecting mirror by welding or bonding. If the vent hole is formed in the reflector base as in the third aspect of the invention, the lamp cooling air can flow out toward the back surface of the concave reflecting mirror, and the discharge lamp can be efficiently cooled. Further, when the reflector base is formed of sintered quartz glass as in the invention of claim 4, it can be easily formed and can be directly welded because the thermal expansion coefficient is the same as that of the sealing tube portion of the discharge lamp.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be specifically described below with reference to the drawings. 1A shows a partial cross-sectional view of the reflector base 30 and FIG. 1B shows a rear view. The reflector base 30 is formed of glass, for example, sintered quartz glass, into a substantially bottomed cylindrical shape. A plurality of vent holes 32 are provided on the same circle on the rear surface 33 of the reflector base 30, and the small diameter portion 31 protrudes from the rear surface 33. As shown in FIG. 2, the small-diameter portion 31 of the reflector base 30 is welded to one sealing tube portion 12 of the discharge lamp 10.
[0013]
In FIG. 2, the discharge lamp 10 is a short arc type mercury lamp having a rated power of 150 W, for example, but a sealing tube portion 12 is integrally connected to both ends of an arc tube 11 made of quartz glass. In the arc tube 11, a cathode 14 and an anode 15 respectively held by the sealing tube portion 12 are arranged to face each other at a predetermined interval. In the arc tube 11, a predetermined amount of mercury and a rare gas are contained. It is enclosed. Molybdenum foil (not shown) is embedded in the sealing tube portion 12, and ends of the cathode 14 and the anode 15 are welded to the molybdenum foil, respectively, and extend outward from the sealing tube portions 12 and 12. The ends of the external lead rods 16 and 16 are also welded to the molybdenum foil. When the external lead rods 16 and 16 are energized, arc discharge occurs between the cathode 14 and the anode 15 to emit light.
In addition, the nozzle | cap | die is not attached to the sealing pipe part 12, but the number of parts has decreased. Further, the discharge lamp 10 may be a short arc type ultra-high pressure rare gas lamp or a metal halide lamp.
[0014]
When welding the small-diameter portion 31 of the reflector base 30 to one sealing tube portion 12 of the discharge lamp 10, first, the one sealing tube portion 12 is inserted into the small-diameter portion 31 with their axes aligned. When the reflector base 30 is formed of sintered quartz glass, the thermal expansion coefficient is equal to the thermal expansion coefficient of the sealing tube portion 12 made of quartz glass. Therefore, the reflector base 30 is heated to 1600 ° C. or higher with an oxygen / hydrogen burner. When melted, the small-diameter portion 31 of the reflector base 30 and one sealing tube portion 12 of the discharge lamp 10 can be directly melted at the melting portion Mt.
[0015]
When the reflector base 30 is formed of glass other than sintered quartz glass, for example, hard glass, the material cost is low, so that the reflector base 30 can be made low cost, but the thermal expansion coefficient is a sealed tube portion made of quartz glass. Since the thermal expansion coefficient is different from the thermal expansion coefficient of 12, it cannot be welded directly, and it is necessary to perform welding by interposing intermediates having sequentially different thermal expansion coefficients.
[0016]
Next, as shown in FIG. 3 (A) or FIG. 3 (B), the discharge lamp to which the reflector base 30 is attached is inserted from the support tube portion 21 formed on the top of the back portion of the concave reflecting mirror 20, The opening edge 30a of the reflector base 30 is brought into contact with and temporarily fixed to the back surface of the concave reflecting mirror 20, and the discharge lamp 10 is actually turned on to obtain the position where the light collection rate is maximized. And the opening edge 30a of the reflector base 30 is heated with a burner in this position, and the opening edge 30a of the reflector base 30 is welded to the back surface of the concave reflecting mirror 20 in the melting part Mt.
[0017]
Alternatively, as shown in FIG. 4, the opening edge 30 a of the reflector base 30 may be bonded to the back surface of the concave reflecting mirror 20 with an adhesive P at a position where the light collection rate is maximized. Since the bonded portion does not reach a very high temperature when the lamp is lit, the impurities of the adhesive P do not adhere to the reflecting surface 22 of the concave reflecting mirror 20 and the delamination is caused by repeated thermal expansion and contraction. There is nothing.
[0018]
Thus, when a current is passed between the pair of external lead rods 16 and 16, an arc discharge occurs between the cathode 14 and the anode 15, and the emitted light is reflected by the reflecting surface 22 and collected efficiently. Then, the cooling air blown from the direction of the opening 23 of the concave reflecting mirror 20 flows along the arc tube 11 and the sealing tube portion 12 which have become high temperature, and is discharged to the outside through the vent hole 32 of the reflector base 30. Is done. Therefore, although the discharge lamp 10 is efficiently cooled, in particular, the sealing tube portion 12 inserted into the support tube portion 21 is efficiently cooled. For this reason, high temperature oxidation of the molybdenum foil embedded in the sealing tube portion 12 is suppressed, the lamp life can be extended, and further miniaturization can be enabled.
[0019]
【The invention's effect】
As described above, the light source device of the present invention is a light source device in which a short arc type discharge lamp and a concave reflecting mirror surrounding the discharge lamp are connected via a reflector base, and the reflector base is made of glass. The reflector base is welded to one sealing tube portion of the discharge lamp, and the opening edge of the reflector base is fixed to the back surface of the concave reflecting mirror. Therefore, it is possible to efficiently cool the reflector base by providing a vent hole. The base attached to the sealing tube portion is unnecessary, the number of parts is small, and the number of mounting steps is also unnecessary. Since no adhesive is used to connect the discharge lamp and the reflector base, impurities contained in the adhesive do not evaporate and adhere to the reflecting surface of the concave reflecting mirror, resulting in a decrease in reflection efficiency and insufficient illuminance. Never become. Furthermore, there is no problem that the adhesive itself repeats expansion and contraction as the lamp blinks, and the discharge lamp and the reflector base can be firmly connected. Moreover, the waiting time for hardening of the adhesive is not required, and the adhesive can be manufactured efficiently.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional view and a rear view of a reflector base.
FIG. 2 is an explanatory diagram of a welded state between a discharge lamp and a reflector base.
FIG. 3 is a cross-sectional view of an embodiment of the present invention.
FIG. 4 is a cross-sectional view of another embodiment.
FIG. 5 is an explanatory diagram of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Discharge lamp 11 Light emission tube 12 Sealing tube part 13 Base 14 Cathode 15 Anode 16 External lead rod 20 Concave reflector 21 Supporting cylinder part 22 Reflective surface 23 Opening of concave reflector 30 Reflector base 31 Small diameter part 32 of reflector base 33 Back side of reflector base P Adhesive Mt Welding part

Claims (4)

A short arc type discharge lamp in which a sealing tube portion is continuously provided at both ends of a quartz glass arc tube in which a pair of electrodes are opposed to each other, and a concave reflecting mirror surrounding the discharge lamp are provided via a reflector base. In the connected light source device,
The light source characterized in that the reflector base is made of glass, the reflector base is welded to one sealing tube portion of the discharge lamp, and the opening edge of the reflector base is fixed to the back surface of the concave reflector. apparatus. The light source device according to claim 1, wherein an opening edge of the reflector base is fixed to a back surface of the concave reflecting mirror by welding or adhesion. The light source device according to claim 1, wherein a vent hole is formed in the reflector base. The light source device according to claim 1, 2 or 3, wherein the glass constituting the reflector base is sintered quartz glass.

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