JP3640458B2 - Light source, light source unit, and projection display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a light source , a light source unit, and a projection display device.
[0002]
[Prior art]
In a projection display device using a liquid crystal panel, light is emitted from a light source toward the liquid crystal panel, and light transmitted through the liquid crystal panel is projected onto a screen by a projection lens. Recently, metal halide lamps are frequently used as light sources for such projection display devices. The metal halide lamp includes first and second electrodes facing each other with a gap in the outer shell of glass, and emits minute metal particles enclosed by discharge between the first and second electrodes. is there.
[0003]
[Problems to be solved by the invention]
A light source such as a metal halide lamp used in a projection display device is required to be capable of irradiating strong light emission, and the light source becomes considerably hot. Therefore, the life of the light source is likely to be shortened, and if the light source cannot be used, the projection display device cannot be used unless the light source can be replaced immediately. Moreover, it is not easy to replace the light source for those who are not used to it. Therefore, it is desired to extend the life of the light source.
[0004]
An object of the present invention is to provide a light source excellent in durability, a light source unit, and a projection display device using the same.
[0005]
[Means for Solving the Problems]
A light source according to the present invention includes an outer shell portion and first and second electrodes facing each other with a gap in the outer shell portion, the first and second electrodes being horizontally disposed, The first and second electrodes are a horizontal direct current lighting type light source to which direct current is supplied, and the first and second electrodes are arranged such that the maximum light emitting part due to discharge is located at the approximate center of the outer shell part . Of the first and second electrodes, the tip of the cathode side electrode is arranged closer to the center of the outer shell than the tip of the anode side electrode .
[0006]
In the conventional light source, the maximum light emitting part due to the discharge is not located at the center of the light source, so that strong light hits a part of the light source, and the part deteriorates early and the life of the light source is shortened. I understood. In the present invention, the first and second electrodes are disposed asymmetrically with respect to the center of the outer shell portion, so that the maximum light emitting portion due to discharge can be positioned substantially at the center of the outer shell portion. As a result, the light source is less likely to be locally deteriorated, and the lifetime can be extended.
[0008]
The light source is preferably a metal halide lamp.
Moreover, the light source part by this invention is equipped with the said light source and a reflector.
In addition, the projection display device according to the present invention uses the above-described light source unit , and since the life of the light source is long, the projection display device can be used reliably for a long time, and the local light emission distribution is eliminated. Display can be obtained.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing a light source according to a reference example. The light source 10 includes an outer shell portion 12 made of a glass tube, and first and second electrodes 14 and 16 that face each other with a gap in the outer shell portion 12. Minute metal particles are enclosed in the outer shell portion 12, and the metal particles emit light by discharge between the first and second electrodes 14 and 16.
[0010]
Linear support portions 18 and 20 extend integrally with the outer shell portion 12. One end of each of the first and second electrodes 14 and 16 is inserted and fixed in the wall of the outer shell portion 12, and the other end projects into the outer shell portion 12. Conductors 22 and 24 are provided in the support portions 18 and 20, the first and second electrodes 14 and 16 are electrically connected to the conductors 22 and 24, and the conductors 22 and 24 are external power sources. To be connected to.
[0011]
The outer shell 12 is formed in a spherical shape, and its center is indicated by O. The outer shell 12 may be formed as an ellipsoid or the like other than a sphere. The first and second electrodes 14 and 16 are disposed asymmetrically with respect to the center of the outer shell 12 so that the maximum light emitting portion due to discharge is located at the approximate center of the outer shell 12. The maximum light emitting part due to the discharge is indicated by L.
[0012]
More specifically, the light source 10 of FIG. 1 is a horizontal AC lighting type light source in which the first and second electrodes 14 and 16 are arranged horizontally and supplied with AC. The first and second electrodes 14 and 16 (and the support portions 18 and 20 serving as attachment portions thereof) pass through the center O of the outer shell portion 12 and connect the first and second electrodes 14 and 16. Is disposed below the line 26 parallel to the. A straight line passing through the center of the first and second electrodes 14 and 16 (and the support portions 18 and 20 serving as the attachment portions) is indicated by 28. The distance between line 26 and line 28 is indicated by d.
[0013]
In the case of a 250 W light source, the diameter of the outer shell 12 is, for example, about 13 mm, the gap length between the first and second electrodes 14, 16 is, for example, about 3-5 mm, and the distance d is, for example, 0.5- It is about 1.0 mm.
[0014]
FIG. 2 shows an example of a conventional horizontal AC lighting type light source, and the respective members are shown with the same reference numerals as those in FIG. In the conventional horizontal alternating current lighting type light source, the first and second electrodes 14 and 16 (and the support portions 18 and 20 serving as the attachment portions) pass through the center O of the outer shell portion 12 and the first and second electrodes. On the line 26 parallel to the line connecting the electrodes 14 and 16. Therefore, when alternating current is supplied to the first and second electrodes 14 and 16, an arc is formed between the first and second electrodes 14 and 16 as indicated by the dotted line, and the minute metal particles enclosed inside are As the temperature rises, it gradually rises in the form of a gas, and the maximum light emitting portion L due to discharge can be shifted to a position shifted upward from the line connecting the first and second electrodes 14 and 16. For this reason, the portion close to the maximum light emitting portion L of the outer shell portion 12 is easily deteriorated by receiving locally strong light, thereby shortening the life of the light source.
[0015]
In the reference example , the first and second electrodes 14 and 16 are disposed below the line 26 passing through the center O of the outer shell portion 12, whereby the maximum light emitting portion L due to discharge is substantially equal to that of the outer shell portion 12. It is located in the center. For this reason, the outer shell 12 is not deteriorated by receiving strong light locally, and the life of the light source can be extended. Further, since the maximum light emitting portion L due to the discharge is located at the approximate center of the outer shell portion 12, when this light source is used as the light source of the projection display device, the luminance of the display due to the position cannot be uneven and good display is achieved. Can be obtained.
[0016]
Figure 3 is a diagram showing a light source according to actual施例of the present invention. The light source 10 includes an outer shell portion 12 made of a glass tube, and first and second electrodes 14 and 16 that face each other with a gap in the outer shell portion 12. Minute metal particles are enclosed in the outer shell portion 12, and the metal particles emit light by discharge between the first and second electrodes 14 and 16. Linear support portions 18 and 20 extend integrally with the outer shell portion 12. One end of each of the first and second electrodes 14 and 16 is inserted and fixed in the wall of the outer shell portion 12, and the other end projects into the outer shell portion 12. Conductors 22 and 24 are provided in the support portions 18 and 20, the first and second electrodes 14 and 16 are electrically connected to the conductors 22 and 24, and the conductors 22 and 24 are external power sources. To be connected to.
[0017]
In this embodiment, the light source 10 is a horizontal direct current lighting type light source in which the first and second electrodes 14 and 16 are horizontally disposed and supplied with direct current. In this case, the first electrode 14 is an anode side electrode, and the second electrode 16 is a cathode side electrode. The tip of the cathode-side electrode 16 is disposed closer to the center O of the outer shell portion 12 than the tip of the anode-side electrode 14. The line 30 is a vertical line passing through the center O of the outer shell 12, and the lines 32 and 34 are lines passing through the tip of the anode side electrode 14 and the tip of the cathode side electrode 16 and parallel to the line 30. That is, the distance b between the line 30 and the line 34 is smaller than the distance a between the line 30 and the line 32. The difference between b and a is preferably about 0.5 to 1.0 mm.
[0018]
In the horizontal DC lighting type light source, unlike the above-mentioned AC lighting type light source, the maximum light emitting portion L due to discharge is less likely to be shifted above the center O of the outer shell portion 12. There is a tendency to be formed on the tip side of the electrode 16. This is because high energy concentrates on the tip of the cathode-side electrode 16 in the horizontal DC lighting type light source. Therefore, the maximum light emitting portion L is substantially at the center O of the outer shell portion 12 by disposing the tip of the cathode-side electrode 16 closer to the center O of the outer shell portion 12 than the tip of the anode-side electrode 14. Will come to be located. For this reason, the outer shell 12 is not deteriorated by receiving strong light locally, and the life of the light source can be extended. Further, since the maximum light emitting portion L due to the discharge is located at the approximate center of the outer shell portion 12, when this light source is used as the light source of the projection display device, the luminance of the display due to the position cannot be uneven and good display is achieved. Can be obtained.
[0019]
FIG. 4 is a diagram showing a reference example, which is an example of a vertical DC lighting type light source. Also in this case, as in the case of the horizontal DC lighting type light source, the maximum light emitting portion L tends to be formed on the tip side of the cathode-side electrode 16. Therefore, also in this case, the maximum light-emitting portion L is formed in the outer shell portion by disposing the tip of the cathode side electrode 16 closer to the center O of the outer shell portion 12 than the tip of the anode side electrode 14. 12 is located approximately at the center O.
[0020]
5 and 6 are views showing an embodiment of a projection display device using the light source of the present invention. The projection display device includes a light source unit 50, and the light source unit 50 includes the light source 10 and the reflector 40 of FIG. 1. Instead of the light source 10 of FIG. 1, the light source 10 of FIG. 3 or FIG. 4 may be used.
The projection type liquid crystal display device includes a light source unit 50, three liquid crystal panels 52, 54, 56, dichroic mirrors 58, 60, 62, 64, total reflection mirrors 66, 68, and a projection lens 70.
[0021]
Each liquid crystal panel 52, 54, 56 includes twisted nematic liquid crystal, and the liquid crystal is sealed between a pair of transparent substrates. A polarizer 72 is disposed before and after each of the liquid crystal panels 52, 54, and 56, and a condenser lens 74 is disposed on the incident side.
[0022]
The light emitted from the light source unit 50 is color-separated by the dichroic mirror 58, for example, blue light transmitted through the dichroic mirror 58 is modulated by the liquid crystal panel 56 via the total reflection mirror 66. The light reflected by the dichroic mirror 58 is further color-separated by the dichroic mirror 60, and the red light reflected by the dichroic mirror 60 is modulated by the liquid crystal panel 54. The green light transmitted through the dichroic mirror 56 is modulated by the liquid crystal panel 52 and further reflected by the total reflection mirror 68. Blue, red, and green light modulated by each liquid crystal panel is color-synthesized by a dichroic mirror 64 and projected onto a screen (not shown) by a projection lens 70.
[0023]
Since the light source unit 50 has good durability and no uneven brightness, the projection display device can display a good image with good durability.
[0024]
【The invention's effect】
As described above, according to the present invention, a light source excellent in durability, a light source unit, and a projection display device using the same can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a light source according to a reference example of the present invention.
FIG. 2 is a diagram showing a conventional light source.
3 is a diagram showing a light source according to actual施例of the present invention.
FIG. 4 is a view showing a light source according to a reference example of the present invention.
FIG. 5 is a view showing a projection display device using a light source unit according to the present invention.
6 is a detailed view of the light source unit of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Light source 12 ... Outer shell part 14, 16 ... Electrode 18, 20 ... Support part 50 ... Light source part

Claims (4)

An outer shell (12), and first and second electrodes (14, 16) facing each other with a gap in the outer shell, the first and second electrodes being horizontally disposed; The first and second electrodes are a horizontal direct current lighting type light source to which direct current is supplied, and the first and second electrodes are arranged such that the maximum light emitting portion due to discharge is located at substantially the center of the outer shell portion. Furthermore, the tip of the cathode side electrode (16) of the first and second electrodes is disposed closer to the center of the outer shell (12) than the tip of the anode side electrode (14) . A light source characterized by The light source according to claim 1, wherein the light source is a metal halide lamp . A light source unit for a projection display device, comprising the light source according to claim 1 and a reflector (40). A projection type display apparatus using the light source unit according to claim 3.

Images