JP3608039B2 - Light source device and projection system using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light source device used for a liquid crystal projector or the like and a projection system using the same.
[0002]
[Prior art]
In recent years, a DLP (digital light processing) projection system using a DMD (digital micro mirror device) as shown in FIG. 3 is rapidly spreading because it is optimal for presentation using a personal computer. (DMD and DLP are registered trademarks of Texas Instruments Inc., USA) The DLP production system using this DMD has rapidly become popular. The DLP production system has a simple optical structure, is compact and lightweight. The main factor is that it is easy. In the known DLP projection system shown in FIG. 3, the light from the ultra-high pressure small short arc discharge lamp 2 mounted on the reflecting mirror 1 is color-separated by the RGB color foil 3, and then the integrator rod lens 4. After passing through the condenser lens 5, it enters the DMD 6, is signal-processed by the DMD element, and is projected as an image through the projection lens of the projector 7 to form a consistent high image without accurate gradation and color reproduction noise.
[0003]
Conventionally, the light source device used in the DLP production system shown in FIG. 3 has a reflecting mirror 1 made of a glass material and a relatively short-focus ellipsoidal shape because of its relationship with an optical system suitable for a DLP type projector. The light source is constructed using an ultra-high pressure small short arc discharge lamp. A light source device in which the ultra-high pressure small short arc discharge lamp 2 shown in FIG. 3 is mounted so as to be incorporated in the central axis of the ellipsoidal reflector 1 is formed by fixing the front glass 8 to the front end of the reflector 1. However, even if the ultra high pressure small short arc discharge lamp 2 is ruptured, the fragments of the high pressure discharge lamp 2 are not scattered.
[0004]
[Problems to be solved by the invention]
By the way, when the reflecting mirror 1 in the light source device described above is configured in a small size, the upper part of the light emitting portion of the lamp 2 swells due to high heat, and the light that is reflected by the ellipsoidal reflecting mirror 1 and radiates in the secondary focal direction. As a part of the contact with the end peripheral surface 41 of the front end side seal portion 40 of the lamp 2 as shown in FIG. 3 causes the temperature of the seal portion 40 to rise, the seal portion outer welding portion 42 is oxidized early, and the same oxidation portion There is a drawback that the electrical resistance increases, cracks are generated by heating, and a pointless state occurs. Further, if the volume surrounded by the reflecting mirror 1 and the front glass 8 is reduced due to a demand for a reduction in size and weight, the temperature of the seal portion outer welding portion 42 is further increased. Therefore, in order to lower the temperature of the seal part outer welding part 42, for example, in order to make the seal part 40 close to the light emitting part away from the light emitting part which is a heat generation source, the dimension of the seal part 40 is increased. Further, a structure in which the dimension of the molybdenum foil 43 to be sealed to the seal portion 40 is made longer can be considered, but if such a structure is used, the second focus focused near the elliptical reflecting mirror 1 having a short focal point is used. Since the seal part circumscribed weld 42 is located, there is a disadvantage that the temperature does not decrease at all and the effect is completely opposite.
[0005]
Further, due to the nature of the DMD element and the optical system, back reflection (in the case of dark expression on the image, the mirror on the DMD 6 reflects the light and heat from the light source device back to the light source device side). There is a temperature about 100 degrees higher than the seal part circumscribed weld temperature of the light source device that is a combination of a parabolic reflector and a front glass found in a projector using a liquid crystal panel. In order to realize a compact and lightweight DLP light source device, an early disadvantage due to the temperature rise of the seal part circumscribed weld 42 becomes a major problem.
[0006]
The present invention has been invented in view of the above points, and can reduce the size of a light source device incorporating a high-pressure discharge lamp in the central axis of an ellipsoidal reflector, and when the light source device is used in a projection system. It is an object of the present invention to prevent the high-pressure discharge lamp as the light source from becoming unsatisfactory due to high temperature oxidation of the seal part circumscribed weld, and to prevent damage to the lamp.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention according to claim 1 is the light source device incorporating a high-pressure discharge lamp in the central axis of the ellipsoidal reflector, wherein the light reflected by the reflector is in the direction of radiating. A heat resistant inorganic heat reflective material is applied to the peripheral surface of the end portion of the front end side seal portion of the high pressure discharge lamp.
[0008]
The invention according to claim 2 is a projection system having an optical system for reflecting light and heat from a light source device incorporating a high-pressure discharge lamp in the central axis of an elliptical reflecting mirror so as to return the light source device to the light source device side. The light source device is a light source device in which a heat-resistant inorganic heat-reflective material is applied to an end peripheral surface of a front end side seal portion of the high-pressure discharge lamp in a direction in which light reflected by the reflecting mirror is emitted. Features.
[0009]
The light source device according to claim 1, by applying a heat-resistant inorganic heat-reflective material to the end peripheral surface of the front end side seal portion of the high-pressure discharge lamp in the direction in which the light reflected by the ellipsoidal reflector radiates . By reflecting light entering from the end peripheral surface of the front end side seal portion, the seal portion can be prevented from becoming high temperature, the light source device can be miniaturized, and the high temperature of the seal portion outer welding portion can be reduced. Disadvantages due to oxidation in the process can be prevented, and further, lamp explosion can be prevented. Further, the projection system of claim 2 uses the light source device of claim 1, so that even if there is back reflection that reflects the light and heat from the light source device back to the light source device side, the front end side of the lamp It is possible to prevent the seal portion from becoming high temperature, and to prevent early failure and damage of the lamp due to oxidation of the seal portion circumscribed weld and generation of cracks.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a light source device according to the present invention and a projection system using the light source device will be described below with reference to FIGS. In FIG. 1, reference numeral 11 denotes a light source device used in the DLP production system using the DMD shown in FIG. Reference numeral 12 denotes a glass reflecting mirror constituting the light source device, which is formed in a semi-elliptical shape. The size of the reflecting mirror 12 is, for example, configured to have a short-focus ellipsoid with an effective inner diameter of 45 mm of the opening, and a first focal length and a second focal length of f1 = 6.5 and f2 = 78.5. . The reflecting mirror 12 is made of borosilicate, has a cold mirror made of titanium oxide and silicon oxide on the inner surface, and a front glass 13 fixed to the front end.
[0011]
Reference numeral 20 denotes an ultra-high pressure small short arc discharge lamp fixed to the central axis in the rotation direction of the ellipsoidal reflecting mirror 12, and for example, a lamp of about 100 watts or 120 watts is used. The high-pressure discharge lamp 20 is configured such that the light emitting portion is positioned in the vicinity of the primary focal point, and the internal volume is configured to have a discharge space of 50 μl. Reference numerals 21 and 22 denote electrodes arranged to face the inside of the lamp 20, and the distance between the electrodes is, for example, about 1.1 mm. A tungsten core rod 23 supports the electrodes 21 and 22 and has a diameter of about φ0.3 mm, for example. A molybdenum foil 24 is connected to one end of the tungsten core rod 23 and sealed and supported by the front end side seal portion 26 and the rear end side seal portion 27. Reference numeral 25 denotes an external lead made of a molybdenum wire having a diameter of 0.5 mm and connected to the other end of the molybdenum foil 24.
[0012]
The light source device 11 of the present invention has a heat-resistant inorganic heat-reflective material 31 on the end peripheral surface 30 of the front-end-side seal portion 26 of the lamp 20 in the direction in which the light reflected by the ellipsoidal reflecting mirror 12 radiates. Thus, the light that enters the seal portion 26 from the end peripheral surface 30 is reflected to prevent the front end side seal portion 26 of the lamp 20 from becoming high temperature. Therefore, if the light source device 11 of the present invention is used in the DLP projection system of FIG. 3 having an optical system that reflects light and heat from the light source device back to the light source device side, the front end side seal portion 26 of the lamp 20 is used. There is little risk of premature failure or damage of the lamp 20 due to the temperature rise of the seal part circumscribed weld 28 which is a weld that connects the external lead 25 to the sealed molybdenum foil 24.
[0013]
The heat-resistant inorganic heat reflective material 31 applied to the end peripheral surface 30 of the front end side seal portion 26 of the lamp 20 is configured by selecting one or more of the following materials (1) to (4).
(1) A colloidal binder is mixed into a powder made of a mixture of aluminum oxide and silicon oxide to form a slurry, and the end peripheral surface 30 of the front end side seal portion 26 of the lamp 20 is immersed in the slurry. The post-slurry is dried and coated with a bulk heat-resistant inorganic heat reflective material. The thickness of the heat-resistant inorganic heat reflective material is about 0.5 mm. When the heat-resistant inorganic heat-reflective material is applied in this way, the length of the seal portion 26 is 24 mm, and the temperature of the seal portion circumscribed weld portion 28 is 335 ° C. (ambient temperature 25 ° C.) when rated at 120 watts. On the other hand, the conventional one without the heat-resistant inorganic heat-reflective material is 390 ° C. (ambient temperature 25 ° C.), and the difference is 55 ° C. Furthermore, it has been experimentally confirmed that when aluminum oxide and silicon oxide are mixed with zirconium oxide, titanium oxide, and zinc oxide, the temperature is further lowered by 10 ° C.
[0014]
(2) A colloidal binder is mixed in powder composed of a mixture of titanium oxide and silicon oxide to form a slurry, and the end peripheral surface 30 of the front end side seal portion 26 of the lamp 20 is immersed in the slurry, Thereafter, the slurry is dried and coated with a bulk heat-resistant inorganic heat-reflective material. The thickness of the heat-resistant inorganic heat reflective material is about 0.5 mm. When the heat-resistant inorganic heat-reflective material is applied in this way, the length of the seal portion 26 is 24 mm, and the temperature of the seal portion outer welded portion 28 is 340 ° C. (ambient temperature 25 ° C.) when rated at 120 watts. On the other hand, the conventional one without the heat-resistant inorganic heat-reflective material is 390 ° C. (ambient temperature 25 ° C. (ambient temperature 25 ° C.), and the difference is 50 ° C.
[0015]
(3) A colloidal binder is mixed into any one of platinum, gold, and rhodium to form a slurry, and the end peripheral surface 30 of the front end side seal portion 26 of the lamp 20 is immersed in the slurry. Dry and coat with bulk heat resistant inorganic heat reflective material. The thickness of the heat-resistant inorganic heat reflective material is about 0.5 mm. When the heat-resistant inorganic heat-reflective material is applied in this way, the length of the seal portion 26 is 24 mm, and the temperature of the welded portion 28 is 340 ° C. (ambient temperature 25 ° C.) when 120 watts are rated. On the other hand, the conventional one without the heat-resistant inorganic heat-reflective material is 390 ° C. (ambient temperature 25 ° C.), and the difference is 50 ° C.
[0016]
(4) When the surface is covered with an iron-based plate such as a stainless steel plate in addition to the one coated with the heat-resistant inorganic heat-reflective material of (1) to (3) above, the length of the seal portion 26 is 24 mm. The temperature of the seal part circumscribed weld 28 becomes 330 ° C. (ambient temperature 25 ° C.) when rated at 120 watts. On the other hand, the conventional product without the heat-resistant inorganic heat-reflective material is 390 ° C. (ambient temperature 25 ° C.), and it has been confirmed as a result of experiments that the difference is 60 ° C. In addition to coating with heat-resistant inorganic heat-reflective material in this way, the surface is further covered with an iron-based plate such as a stainless steel plate, so the temperature is further lowered because the radiant heat is reduced with the iron-based plate. Is due to. Further, when the heat-resistant inorganic heat-reflective material (1) to (3) is not coated and only covered with an iron-based plate such as a stainless steel plate, the seal portion 26 has a length of 24 mm, and the seal portion circumscribed welded portion. The temperature of 28 can be set to 350 ° C. (ambient temperature 25 ° C.) when rated at 120 watts.
[0017]
【The invention's effect】
The light source device of the present invention is obtained by applying a heat-resistant inorganic heat-reflective substance to the end surface of the front end side seal portion of the high-pressure discharge lamp in the direction in which the light reflected by the ellipsoidal reflector radiates. The light that strikes the peripheral surface of the end of the front end side seal portion can be reflected to prevent the seal portion from becoming high temperature. Therefore, the seal portion circumscribed weld that causes premature failure or damage of the lamp. Oxidation and cracks can be prevented and the apparatus can be downsized. Further, in the projection system of the present invention using the light source device, even if there is back reflection that reflects light and heat from the light source device back to the light source device side, the front end side seal portion of the lamp becomes high temperature. There is little risk of oxidation or cracking at the welded part of the seal part.
[Brief description of the drawings]
FIG. 1 shows an example of a light source device according to the present invention.
FIG. 2 is an enlarged view showing a main part of a lamp serving as a light source of the light source device according to the invention.
FIG. 3 is a schematic diagram of a known projection system.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 Light source device 12 Ellipsoidal reflector 20 Super high pressure small short arc discharge lamps 21 and 22 Electrode 23 Tungsten core rod 24 Molybdenum foil 25 External lead 26 made of molybdenum wire Front end side seal portion 30 End portion peripheral surface of the front end side seal portion 31 Heat-resistant inorganic heat-reflective material

Claims (2)

In a light source device incorporating a high-pressure discharge lamp in the central axis of an elliptical reflecting mirror, heat resistance is provided to the end peripheral surface of the front-end seal portion of the high-pressure discharge lamp in the direction in which light reflected by the reflecting mirror radiates A light source device characterized by applying an inorganic heat reflective material. In a projection system having an optical system for reflecting light and heat from a light source device incorporating a high-pressure discharge lamp on the center axis of an ellipsoidal reflector so as to return the light source device to the light source device side, the light source device includes the reflector A projection system comprising: a light source device in which a heat-resistant inorganic heat-reflective material is applied to a peripheral surface of an end portion of the front-end-side seal portion of the high-pressure discharge lamp in a direction in which light reflected by the light is emitted .

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