JP2005072013A - Discharge lamp, light source device, and projection display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp as a reliable and compact light source device by fixing sealing parts sealing short metal foils of the discharge lamp with a concave mirror. <P>SOLUTION: The discharge lamp is provided with an arc tube 170 forming a discharge space, the sealing parts 171 and 172 formed on both ends of the arc tube, the metal foils 173 and 174 sealed by the sealing parts, respectively, electrodes 175 and 176 with one-side ends connected to the metal foils and the other ends arranged facing the arc tube, outer conductors 177 and 178 with one-side ends connected to the metal foils and the other ends protruding outside the sealing parts, and a discharge medium sealed in the arc tube. Lengths of the metal foils are different. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a discharge lamp, a light source device that forms illumination light using the discharge lamp, and a spatial light modulation element (for example, a liquid crystal element) that forms an optical image by supplying a video signal from the light source device and the outside. The present invention relates to a projection display device that projects a large screen image on a screen using a projection lens.

  Small discharge lamps typified by metal halide lamps and ultra-high pressure mercury lamps are widely used as light sources for projection display devices and the like. In such a case, a light source device is generally configured by combining a discharge lamp and a concave mirror, and this is used as a light source for a projection display device.

  FIG. 17 shows a configuration example of a conventional discharge lamp. The discharge lamp 321 mainly includes an arc tube 301, sealing portions 302 and 303, metal foils 304 and 305, electrodes 306 and 307, external conductors 308 and 309, and discharge media 310, 311, and 312. Quartz glass is used for the arc tube 301 and the sealing portions 302 and 303, tungsten is used for the electrodes 306 and 307, molybdenum foil is used for the metal foils 304 and 305, and molybdenum is used for the external conductors 308 and 309. As the discharge medium, mercury 310, a light emitting metal 311 such as a metal halide, and a rare gas 312 such as argon are mainly used.

  By applying a predetermined voltage to the external conductors 308 and 309, arc discharge occurs between the electrodes 306 and 307, and light emission specific to the mercury 310 and the metal halide 311 is obtained. Argon gas 312 is used to improve startability.

  Since this type of discharge lamp has a very short distance between electrodes and a large current flows at the start, blackening due to electrode deformation or evaporation of the electrode material is likely to occur, and it is difficult to extend the life. On the other hand, various discharge lamps whose lamp life is improved by devising the electrode structure have been disclosed (for example, JP-A-7-192688 and JP-A-10-92377). 18 to 20 are enlarged views showing configuration examples of the electrodes.

FIG. 18 is an example in which a coil 331 is provided at the tip of the electrode 330 to improve heat dissipation, and deterioration and deformation due to excessive temperature rise at the tip are suppressed.
FIG. 19 shows an example in which a discharge part 342 having a diameter larger than the axis of the electrode 341 is provided at the tip of the electrode 340 to increase thermal conductivity and suppress deterioration and deformation due to excessive temperature rise at the tip. This type of electrode is used as the anode of a direct current discharge lamp.

In FIG. 20, a coil is wound thickly around the tip of the electrode 350, and this tip portion is melted by discharge so as to be a solid body with the electrode shaft 351, thereby forming a discharge portion 352 having a diameter larger than that of the electrode shaft 351. This is an example in which deterioration and deformation of the electrode are suppressed by providing a heat dissipating part 353 in which the coil is integrally melted behind the part 352. The heat radiation part 353 is configured using a coil or a cylindrical electrode member.
JP-A-7-192688 Japanese Patent Laid-Open No. 10-92377 JP-A-6-275238

However, the electrode structures shown in FIGS. 18 to 20 have the following problems.
In the case of FIG. 18, since the contact area between the electrode 330 and the coil 331 is small, the heat conduction is low, and it is difficult to obtain a sufficient heat dissipation effect. Further, when the coil 331 is too thin, the coil 331 is melted and deformed. The coil 331 may be thickened, but tungsten used for the electrode 330 is hard and difficult to wind the coil 331. In addition, there is a problem that the arc spot of discharge moves to the tip of the electrode or the end of the coil, making it difficult to stabilize the arc.

  In the case of FIG. 19, if the large-diameter discharge part 342 is made too large, the electrode 340 hardly rises to a temperature necessary for emitting thermoelectrons, and there are problems such as deterioration of startability and disappearance. This is a big problem particularly when the lamp is turned on by alternating current, and it has been difficult to use such an electrode for alternating current lighting.

  In the case of FIG. 20, since the discharge part 352 and the coil 353 are integrally formed continuously, the heat conduction between the discharge part 352 and the coil 353 is high, and the discharge part 352 rises to a temperature required for thermionic emission. Therefore, the startability deteriorates and disappears as in FIG. This is a big problem especially when the discharge lamp is turned on by alternating current. The electrode as shown in FIG. 20 is obtained by discharging an electrode having a coil 353 wound around an electrode shaft 351 in an inert gas atmosphere such as nitrogen gas or argon gas, and melting the tip portion thereof. Manufactured. In a discharge lamp, an electrode obtained by adding a doping material such as thorium to tungsten as an electrode material is often used in order to improve startability. However, the electrode produced by the manufacturing method as described above has a problem that the dope material evaporates when the tip portion is melted. Further, since the recrystallization of the tip portion proceeds by melting, there is a problem that the strength is weak and the processing is difficult.

  On the other hand, when this type of discharge lamp is used in a projection display device, a light source is generally configured in combination with a concave mirror. FIG. 21a shows an example of the configuration. 21b is a cross-sectional view taken along the line AA in FIG. 21a. The concave mirror 371 has a reflective coating 372 on its inner surface, and efficiently reflects the emitted light from the lamp 360 in a predetermined direction. The concave mirror 371 is provided with a lamp insertion portion 373 and a lead extraction hole 374. In the lamp 360, the sealing portion 362 is inserted into the lamp insertion portion 373 and is fixed to the concave mirror 371 with a heat-resistant adhesive 375. In addition, an extended conductor 376 is connected to the external conductor 369, and the other end of the extension conductor 376 is drawn out of the concave mirror 371 from the conductor extraction hole 374. By applying a predetermined voltage between the external conductor 368 and the extension conductor 376, the light emission of the lamp 360 can be obtained.

A lamp used in a projection display device is required to be as small as possible and have a long life. However, the conventional light source shown in FIG. 21a has the following problems.
The first problem is that the metal foils 364 and 365 and the external conductors 368 and 369 provided at both ends of the lamp 360 are disconnected due to oxidation, and the lamp life is shortened. In the case of the light source shown in FIG. 21a, as shown in the enlarged sectional view of AA in FIG. 21b, distortion due to thermal stress occurs between the external conductor 369 and the sealing portion 363 during sealing. A gap B is formed. Therefore, the end portions of the external conductor 369 and the metal foil 365 on the side of the external conductor 369 are in contact with air, and oxidation of these portions is promoted under extremely high temperature conditions during lamp operation. Although the time until disconnection due to oxidation varies depending on the temperature, for example, when molybdenum is used for the metal foil, it is approximately 5000 hours under conditions of 350 ° C. in air. The same applies to the external conductor 368 and the sealing portion 362.

  Generally, a discharge lamp used in a projection display device has a very high temperature during lighting, and the arc tube 361 has a maximum temperature close to 1000 ° C. Therefore, due to heat conduction from the arc tube 361 and heat conduction from the electrodes 366 and 367, the temperature in the vicinity of the connection between the metal foils 364 and 365 and the external conductors 368 and 369 reaches several hundred degrees. The temperature can be lowered by forcibly cooling with a fan or the like. However, if the temperature is lowered to the temperature of the arc tube 361, the evaporation of the luminescent metal is suppressed, and the luminous efficiency is significantly lowered. Therefore, extremely local cooling is necessary and difficult.

  In order to solve this problem, the conventional discharge lamp uses a sufficiently long metal foil to reduce the temperature rise due to heat conduction and suppress disconnection due to oxidation. However, there is a problem that the total length of the lamp becomes too long by lengthening the metal foil, making it difficult to reduce the size of the light source.

  Secondly, since the luminescent metal evaporates during lamp operation, the pressure in the arc tube is extremely high, for example, several tens of atmospheres for metal halide lamps and several tens of MPa (megapascal) for ultrahigh pressure mercury lamps. There was a problem that the arc tube was easily damaged.

  The discharge lamp of the present invention aims to improve startability, arc stability, and lamp life even when the arc is short. In addition, the light source device of the present invention is compact, highly reliable, and suitable for use mainly in a projection display device, and efficiently collects the emitted light of a discharge lamp. In addition, if the light source device of the present invention is used, a projection display device that is bright, compact, and highly reliable can be provided.

  The first discharge lamp of the present invention includes an arc tube that forms a discharge space, a sealing portion formed at both ends of the arc tube, a metal foil sealed at the sealing portion, and one end at the end. An electrode that is connected to the metal foil and has the other end disposed opposite to the inside of the arc tube, and an external conductor that has one end connected to the metal foil and the other end protruded outside the sealing portion, A discharge medium sealed in the arc tube, and the metal foils have different lengths.

In the first discharge lamp, the discharge medium includes an inert gas and mercury.
In the first discharge lamp, the arc tube is made of quartz glass or sapphire glass.
In the first discharge lamp, a holding unit is provided in a sealing portion in which a short metal foil is sealed.

In the first discharge lamp, the holding means is made of metal.
A first light source device of the present invention includes a first discharge lamp and a concave mirror that reflects light emitted from the discharge lamp from a predetermined direction, and the discharge lamp is sealed with a short metal foil. The provided sealing part is fixed to the concave mirror.

  A second light source device of the present invention includes a discharge lamp and a concave mirror that reflects light emitted from the discharge lamp in a predetermined direction, and the discharge lamp is sealed at both ends of the arc tube. The metal foils sealed in the sections have different lengths, the concave mirror has an opening through which reflected light is emitted, and a lamp insertion section provided on the opposite side of the opening, and the discharge lamp has a long length. A sealing part in which a short metal foil is sealed is inserted into the lamp insertion part, and the center of the light emitting region formed in the arc tube is arranged so as to substantially coincide with the focal point on the short side of the concave mirror. Is.

  According to a third light source device of the present invention, a discharge lamp, a concave mirror that reflects light emitted from the discharge lamp in a predetermined direction, and an opening on the reflected light emission side of the concave mirror are arranged. A light-transmitting sealing means for forming a sealed space inside, and an inert gas is sealed in the sealed space.

  According to a fourth light source device of the present invention, a discharge lamp, a concave mirror that reflects light emitted from the discharge lamp in a predetermined direction, and an opening on the reflected light emission side of the concave mirror are arranged. Translucent sealing means for forming a sealed space inside, and gas is sealed in the sealed space at a pressure higher than 1 atm and lower than the operating pressure of the discharge lamp. .

  A fifth light source device of the present invention includes a discharge lamp having an operating pressure of 10 MPa (megapascal) or more, a concave mirror that reflects light emitted from the discharge lamp in a predetermined direction, a translucent sealing means, And the discharge lamp has different lengths of metal foils sealed in sealing portions provided at both ends of the arc tube, and the concave mirror has an opening for reflecting light and an opposite of the opening. The discharge lamp has a lamp insertion portion provided on the side, and the discharge lamp has a light emitting region formed in the arc tube while inserting a sealing portion in which a short metal foil is sealed into the lamp insertion portion. The center of the concave mirror is arranged so as to substantially coincide with the focal point on the short side of the concave mirror, and the sealing means is arranged in the opening of the concave mirror.

In the third or fourth light source device, the translucent sealing means is preferably Pyrex (registered trademark) glass.
In the third or fourth light source device, the light-transmitting sealing means is preferably provided with a coating for reflecting at least one of infrared rays and ultraviolet rays.

In the third or fourth light source device, the translucent sealing means is preferably provided with an antireflection coating for preventing reflection of incident light.
In the third or fourth light source device, it is preferable that the discharge lamp fixes a sealing portion in which a short metal foil is sealed to the concave mirror.

In the third or fourth light source device, the concave mirror is preferably an ellipsoidal mirror.
In the third or fourth light source device, it is preferable that the discharge lamp has an operating pressure of 10 MPa (megapascal) or more.

  In the second or fifth light source device, the concave mirror is an ellipsoidal mirror, and the distance from the top of the ellipsoidal lamp insertion portion side to the concave mirror opening side end of the long metal foil is the major axis length of the ellipsoidal surface. If it is 1/2 or less, it is preferable.

ADVANTAGE OF THE INVENTION According to this invention, the light source device which condenses the emitted light of a lamp | ramp efficiently can be implement | achieved. In addition, a small and highly reliable light source device can be realized.
The projection display device of the present invention projects a light source, an image forming unit that is illuminated by the light source and forms an optical image in accordance with a video signal, and an optical image formed on the image forming unit on a screen. Projection means, and the light source is any one of the first to fifth light source devices.

  According to the present invention, a small, reliable and bright projection display device can be realized.

Moreover, the light source device of the present invention is compact and highly reliable, which is suitable mainly for use in a projection display device, and can efficiently collect the emitted light of the discharge lamp.
In addition, if the light source device of the present invention is used, a projection display device that is bright, compact, and highly reliable can be provided.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.
1a and 1b are configuration examples showing a first embodiment of the discharge lamp of the present invention. FIG. 1b is an enlarged cross-sectional view of the electrode portion shown in FIG. 1a.

  10 is an arc tube, 11 and 12 are sealing parts, 13 and 14 are metal foils, 15 and 16 are electrodes, 17 and 18 are coils as heat dissipation conductors, 19 and 20 are external conductors, and 21 and 22 are discharge media. The mercury and argon gases 31 are the discharge lamp of the present invention.

  The arc tube 10 is transparent quartz glass having an outer diameter of 15 mm and a maximum thickness of 3 mm, and a spherical or elliptical discharge space is formed therein. Transparent quartz glass has excellent heat resistance and is a suitable material for a discharge lamp having an extremely high operating temperature. There is also an advantage that the light transmittance is high. In addition, a high thermal conductivity material such as sapphire glass can be used. When the thermal conductivity is high, there is an advantage that the temperature distribution of the arc tube 10 becomes uniform, the luminous characteristics are stabilized, and the arc tube 10 can be easily cooled.

  Sealing portions 11 and 12 are provided at both ends of the arc tube 10. The sealing parts 11 and 12 are transparent quartz glass similar to the arc tube 10. Metal foils 13 and 14 each having a width of 3.5 mm and a length of 16 mm are sealed to the sealing portions 11 and 12, respectively. The metal foils 13 and 14 use refractory metal molybdenum.

  One end of each of the electrodes 15 and 16 is connected to the metal foils 13 and 14, and the other end is disposed opposite to the arc tube 10 with a distance of 2.0 mm. As shown in FIG. 1b, the electrode 15 includes an electrode shaft 15a and a discharge portion 15b that is integrally formed with a larger diameter than that of the electrode shaft 15a. Pure tungsten is used as the material of the electrode 15. The electrode 15 can be easily obtained by cutting out a cylindrical electrode material. Alternatively, the electrode 15 having a predetermined shape may be formed using a mold made of molybdenum, carbon, ceramic, or the like. The outer diameters of the electrode shaft 15a and the discharge part 15b are 1.0 mm and 3.0 mm, respectively. The length of the discharge part 15b in the axial direction is 1.8 mm. A coil 17 is wound behind the discharge portion 15b so as to surround the electrode shaft 15a. The coil 17 is pure tungsten having a wire diameter of 0.5 mm. For example, the coil 17 may be fixed to the electrode shaft 15a by spot welding or the like. Similarly, the electrode 16 includes an electrode shaft 16a and a discharge portion 16b having a diameter larger than that of the electrode 16, and a coil 18 is wound around the electrode shaft 16a behind the discharge portion 16b.

  One end of each of the external conductors 19 and 20 is connected to the metal foils 13 and 14, and the other end protrudes outside the sealing portions 11 and 12. As with the metal foils 13 and 14, molybdenum is used for the external conductors 19 and 20. By applying a predetermined voltage to the external conductors 19 and 20, arc discharge is generated between the electrodes 15 and 16, and light emission specific to the mercury 21 can be obtained along with evaporation of the mercury 21 as a discharge medium. Further, argon gas 22 is sealed as a rare gas at a predetermined pressure to improve the startability of the lamp.

  As the rare gas, an inert gas such as xenon gas may be used in addition to the argon gas, and the startability can be improved. In addition to the rare gas, a predetermined amount of a halogen gas, such as iodine, bromine, or chlorine, may be enclosed. These halogen gases combine with tungsten as an electrode material to generate a halogen cycle and prevent blackening of the inner wall of the arc tube due to scattering of tungsten during lighting, thereby improving the lamp life.

  If the discharge lamp 31 is configured using the electrodes 15 and 16, a light emitting portion by arc discharge is formed between the large-diameter discharge portions 15b and 16b. Since the discharge parts 15b and 16b have a large heat capacity and good thermal conductivity, there is an effect of suppressing excessive temperature rise of the electrodes 15 and 16 even when a relatively large current flows. Thereby, the deformation | transformation of the electrodes 15 and 16 and evaporation of an electrode substance are suppressed significantly, and a lamp lifetime is improved. The coils 17 and 18 increase the heat dissipation of the electrode shafts 15a and 16a to suppress excessive temperature rise and prevent the portions from being thinned or broken. In addition, the arc spot does not become unstable unlike the electrode of FIG. 17, and stable light emission can be obtained. Furthermore, since the electrodes 15 and 16 and the coils 17 and 18 are not integrally melted and separated, the thermal conductivity between the discharge portions 15b and 16b and the coils 17 and 18 is low. Moreover, since the shape is appropriately set so that the heat capacity of the discharge parts 15b and 16b does not become too large, the discharge parts 15b and 16b are not cooled excessively and the temperature at which thermionic electrons can be emitted. As compared with the case of using the electrodes shown in FIGS. 19 and 20, the startability is greatly improved.

  As described above, according to the configuration of the present invention, an electrode composed of an electrode shaft and a discharge portion having a larger outer diameter than the electrode shaft integrally formed at the tip of the electrode shaft is used. By providing a heat dissipating conductor surrounding the electrode shaft on the rear side, a discharge lamp having excellent startability and a long life even with a short arc can be realized.

2a and 2b are configuration examples showing a second embodiment of the discharge lamp of the present invention. 2b is an enlarged sectional view of the electrode portion shown in FIG. 2a.
In the discharge lamp 51, the configuration other than the electrodes 41 and 42 is the same as that shown in FIG. 1a. The difference from FIG. 1 a is that the tip of the large-diameter discharge part 41 b constituting the electrode 41 has a taper 41 c shape. The taper 41c is formed at an angle of 45 ° with respect to the electrode shaft 41a, and the tip of the discharge part 41b has a circular cross section with a diameter of 1.0 mm. Similarly to the electrode 41, the electrode 42 is also formed with a taper 42c at an angle of 45 ° with respect to the electrode 42a.

  In addition to the effects obtained in the embodiment of FIGS. 1a and 1b, the present embodiment further provides the following effects. By providing the tips 41c and 42c at the tips of the discharge portions 41b and 42b to reduce the tip diameter φ, the electron emission is enhanced, and the startability is further improved compared to that shown in FIGS. 1a and 1b. . At the same time, the rise time until the lamp reaches a stable state is also greatly improved. Further, since thermionic emission mainly occurs from the tips of the discharge portions 41b and 42b, the arc radial width is reduced and the luminance of the light emitting portion is increased compared to the case without the tapers 41c and 42c. is there. Further, since the tip diameter φ of the discharge portions 41b and 42b is small, the so-called bright spot movement in which the arc spot moves at the tips of the discharge portions 41b and 42b is less likely to occur, and the arc stability during lighting is improved. Furthermore, since the range in which the emitted light from the light emitting part is shielded by the large-diameter discharge parts 41b and 42b can be reduced, the emitted light can be used efficiently. Furthermore, the tip portion is easier to process than the conventional electrode shown in FIG. 20, and the yield is improved.

In order to obtain a sufficient effect of the present invention, the following conditional expression may be satisfied.
φ / L ≦ 0.6 (Formula 1)
20 ° ≦ θ ≦ 60 ° (Formula 2)
However, L is the space | interval of the electrodes 41 and 42 in the arc_tube | light_emitting_tube 10, (phi) is the diameter of the front-end | tip of discharge part 41b, 42b, (theta) is the angle | corner which the taper 41c, 42c makes with electrode axis 41a, 42a.

  In Formula 1, it is not preferable that φ / L is larger than the upper limit value because the above-described effects regarding startability, rise time, and arc stability are reduced. Further, the amount of light shielded by the discharge portions 41b and 42b increases, which is not preferable.

  In Equation 2, it is not preferable that θ is smaller than the lower limit value because the tips of the discharge portions 41b and 42b become too thin, and the electrodes 41 and 42 are likely to deteriorate. On the other hand, if the value is larger than the upper limit value, the above-described effects relating to startability, rise time, and arc stability are reduced, which is not preferable. Further, the amount of light shielded by the discharge portions 41b and 42b increases, which is not preferable.

  The electrode may be an electrode 45 whose tip of the discharge part is spherical as shown in FIG. In this case, the diameter φ of the tip of the discharge part 45b in Equation 1 may be defined by the distance between the contact points between the outer periphery 46 of the sphere and the taper 45c.

  As described above, according to the configuration of the present invention, an electrode composed of an electrode shaft and a discharge portion integrally formed at the tip of the electrode shaft and having a larger outer diameter than the electrode shaft and a taper is provided. Used and equipped with a heat-dissipating conductor that surrounds the electrode axis behind the discharge part, making it easy, without inducing unstable discharge, excellent startability and start-up performance during lighting, and efficient use of synchrotron radiation It is possible to realize a discharge lamp having a long life even with a short arc.

4a and 4b are configuration examples showing a third embodiment of the discharge lamp of the present invention. 4b is an enlarged cross-sectional view of the electrode portion shown in FIG. 4a.
The configuration of the discharge lamp 71 other than the electrodes 61 and 62 is the same as that shown in FIG. The difference from FIG. 1a is that the electrode 61 is composed of an electrode shaft 61a and a cylindrical conductor 61b provided at the tip thereof. The electrode shaft 61a is pure tungsten having an outer diameter of 1.0 mm. The cylindrical conductor 61b has an outer diameter of 3.0 mm. The cylindrical conductor 61b has a length in the axial direction of 1.8 mm and is pure tungsten, and is fitted into the tip of the electrode shaft 61a. The cylindrical conductor 61b can be fixed to the electrode shaft 61a by spot welding or the like, for example. As with the electrode 61, the electrode 62 is also provided with a cylindrical conductor 62b at the tip.

  Heat generated in the electrode shafts 61a and 62a is radiated through the cylindrical conductors 61b and 62b. Since the cylindrical conductors 61b and 62b have good contact properties with the electrode shafts 61a and 62a and high thermal conductivity, the tips of the electrode shafts 61a and 62a having the highest temperature are efficiently radiated. Compared to the electrode shown in FIG. 1b, the large-diameter portion at the tip is formed as a separate body, so there is an advantage that this portion does not need to be cut out and can be manufactured more easily.

  By disposing a heat dissipating conductor such as the coil 65 behind the cylindrical conductor 61b, the heat transmitted to the back of the electrode shaft 61a can be efficiently dissipated, so that the electrode shaft 61a can be prevented from being thinned or broken. The same applies to the electrode 62.

  4a and 4b, the end surfaces of the electrode shafts 61a and 62a and the end surfaces of the cylindrical conductors 61b and 62b are arranged to be flush with each other. However, the ends of the electrode shafts 61a and 62a are cylindrical conductors. You may fit so that it may protrude slightly from the end surface of 61b, 62.

  As in the electrode 66 shown in FIG. 5, a cylindrical conductor 66b provided with a taper 67 notched inward may be used on the inner peripheral portion on the side far from the tip of the electrode shaft 66a. The taper 67 has an effect of increasing the surface area of the cylindrical conductor 66b and further improving heat dissipation. At the same time, if the angle η of the taper 67 is adjusted and the contact area between the electrode shaft 66a and the cylindrical conductor 66b is set appropriately, the startability can be further improved. A heat radiating conductor such as a coil 65 may be provided behind the cylindrical conductor 66b. The same applies to the electrode 62.

  Furthermore, as shown in FIG. 6, the same effect can be obtained by using an electrode 68 in which a cylindrical conductor 68b whose inner periphery does not penetrate is fitted to the tip of the electrode shaft 68a. A heat-radiating conductor such as the coil 65 or an inner peripheral taper similar to that shown in FIG. 5 can be provided.

However, in the present invention, in FIG. 4, FIG. 5, and FIG. 6, the heat radiating conductor such as the coil 65 is arranged, but the coil 65 may not be provided.
As described above, according to the configuration of the present invention, by using an electrode including the electrode shaft and the cylindrical conductor fitted to the tip portion of the electrode shaft, it is easy to manufacture and unstable discharge. Therefore, a long-life discharge lamp can be realized even with a short arc.

7a and 7b are configuration examples showing a fourth embodiment of the discharge lamp of the present invention. FIG. 7b is an enlarged cross-sectional view of the electrode portion shown in FIG. 7a.
In the discharge lamp 91, the configuration other than the electrodes 81 and 82 is the same as that shown in FIG. The difference from FIG. 4a is that the tip of the cylindrical conductor 81b constituting the electrode 81 is tapered 81c. The taper 81c is formed at an angle of 45 ° with respect to the axis of the electrode 81, and the outer diameter of the tip of the cylindrical conductor 81b is 1.0 mm, which is equal to the outer diameter of the electrode shaft 81a. Regarding the electrode 82, similarly to the electrode 81, a taper 82 c is formed on the cylindrical conductor 82 b. By disposing a heat dissipating conductor such as the coil 85 behind the cylindrical conductor 81b, heat transmitted to the back of the electrode shaft 81a can be efficiently dissipated, so that the electrode shaft 81a can be prevented from being thinned or broken. The same applies to the electrode 82.

However, in the present embodiment, a heat radiating conductor such as the coil 85 is arranged, but the coil 85 may not be provided.
In this embodiment, in addition to the effects obtained in FIG. 4, startability and rise time are further improved. At the same time, there is an advantage that the luminance of the light emitting part is increased. Also, bright spot movement is less likely to occur, and arc stability during lighting is improved. Furthermore, since the area where the radiated light from the light emitting portion is shielded by the cylindrical conductors 81b and 82b is small, the radiated light can be used efficiently.

In order to obtain a sufficient effect of the present invention, the following conditional expression may be satisfied.
φ / L ≦ 0.6 (Formula 3)
20 ° ≦ θ ≦ 60 ° (Formula 4)
However, L is the space | interval of the electrodes 81 and 82 in the arc_tube | light_emitting_tube 10, (phi) is the outer diameter of the end surface near the front-end | tip of the electrode shafts 81a and 82a in the cylindrical conductors 81b and 82b, (theta) is taper 81c and 82c. It is a corner.

  In Expression 3, it is not preferable that φ / L is larger than the upper limit value because the above-described effects on startability, rise time, and arc stability are reduced. Further, the amount of light shielded by the cylindrical conductors 81b and 82b increases, which is not preferable.

  In Equation 4, it is not preferable that θ is smaller than the lower limit value because the tips of the cylindrical conductors 81b and 82b become too thin, and the electrodes 81 and 82 are likely to deteriorate. On the other hand, if the value is larger than the upper limit value, the above-described effects relating to startability, rise time, and arc stability are reduced, which is not preferable. Further, the amount of light shielded by the cylindrical conductors 81b and 82b increases, which is not preferable.

  As described above, according to the configuration of the present invention, the electrode configured by the electrode shaft and the cylindrical conductor that surrounds the vicinity of the tip end portion of the electrode shaft and whose outer diameter portion on the tip end side of the electrode shaft is tapered. Is easy to manufacture, does not induce unstable discharge, has excellent startability and start-up performance during lighting, can efficiently use synchrotron radiation, and has a long life even in short arcs A lamp can be realized.

8a and 8b are configuration examples showing a fifth embodiment of the discharge lamp of the present invention. FIG. 8b is an enlarged sectional view of the electrode portion shown in FIG. 8a.
The discharge lamp 121 is an AC-lighted ultra-high pressure mercury lamp. The ultra-high pressure mercury lamp is small in size, has a high luminance of the light emitting portion, and is widely used in projection display devices. In general, this type of lamp is mainly used in horizontal lighting.

  The arc tube 101 is quartz glass having an outer diameter of 12 mm and a maximum wall thickness of 2.5 mm, and molybdenum foils 104 and 105 having a width of 2.5 mm and a length of 20 mm are sealed in the sealing portions 102 and 103. The pure tungsten electrodes 106 and 107 connected to the molybdenum foils 104 and 105 are opposed to each other with a distance of 1.5 mm in the arc tube 101. In the arc tube 101, 170 mg / cc mercury, 200 mb argon gas, and a very small amount of bromine are sealed. Bromine has the function of suppressing the blackening of the inner wall of the arc tube 101 due to tungsten evaporated from the electrodes 106 and 107 by the halogen cycle and improving the life of the lamp 121.

  By applying an AC voltage having a predetermined frequency to the external conductors 108 and 109 connected to the molybdenum foils 104 and 105, light emission of mercury 110 can be obtained. The power when the lamp 121 is stable is set to 200 W.

  The electrode 106 includes an electrode shaft 106a and a discharge portion 106b having a diameter larger than that of the electrode shaft 106a. The diameter of the electrode shaft 106a is 0.5 mm. The discharge part 106b has an outer diameter of 1.8 mm, a tip diameter of 0.3 mm, a length in the electric core direction of 2.5 mm, and a taper angle of 30 °. By disposing a heat dissipating conductor such as the coil 112 behind the discharge portion 106b, the heat transmitted to the back of the electrode shaft 106a can be efficiently dissipated, so that the electrode shaft 106a can be prevented from being thinned or broken. The electrode 107 has the same configuration.

However, in this embodiment, a heat radiating conductor such as the coil 112 is disposed, but the coil 112 may not be provided.
The distance between the electrodes 106 and 107 is as short as 1.5 mm, and a very bright light emitting portion is formed between them. If the discharge lamp 121 is configured using the electrodes 106 and 107, even when the light emitting portion has high luminance and the electrodes 106 and 107 generate a great amount of heat, electrode deterioration can be suppressed and the life of the lamp can be extended. . Further, since the shapes of the discharge portions 106b and 106b are appropriately set, the startability is good, the rise time is fast, and the arc stability at the time of lighting is good. Furthermore, since the light shielding region of the electrodes 106 and 107 with respect to the radiated light from the light emitting unit can be reduced, the radiated light can be used efficiently.

  FIG. 9 shows the relationship between the angles of the tapers 106c and 107c and the lamp rising time for the discharge lamp shown in FIG. 8, the horizontal axis is the elapsed time after lighting, and the vertical axis is the light output. . The light output on the vertical axis is shown as a relative value when the light output when the power of each lamp is stable is 1.0. Compared with the case where the conventional electrode of FIG. 14 is used, the discharge lamp of the present invention has a significantly shortened rise time. The larger the angles of the tapers 106c and 107c, the longer the rising time, and good rising performance is obtained when the angles of the tapers 106c and 107c are in the range of 20 ° to 60 °.

In order to obtain a sufficient effect of the present invention, the following conditional expression may be satisfied.
φ / L ≦ 0.6 (Formula 5)
20 ° ≦ θ ≦ 60 ° (Formula 6)
However, L is the space | interval of the electrode in an arc_tube | light_emitting_tube, (phi) is the diameter of the front-end | tip of a discharge part, (theta) is an angle which a taper makes with an electrode axis.

  As described above, according to the configuration of the present invention, by using an electrode having a discharge portion having a diameter larger than that of the electrode axis and appropriately setting the shape thereof, discharge with a large electrode load such as an ultrahigh pressure mercury lamp is performed. Even when the lamp is turned on with an alternating current, a discharge lamp with excellent startability and start-up performance, high light utilization efficiency, and long life even with a short arc can be realized without inducing unstable discharge.

In the first, second, or fifth embodiment of the discharge lamp, the distance between the electrodes is 2 mm or less, the outer diameter of the electrode shaft is D1, the outer diameter of the discharge portion is D2, and the length of the discharge portion in the electrode axis direction. Is D3,
2.0 ≦ D2 / D1 ≦ 5.0 (Formula 7)
D3 / D1 ≦ 9.0 (Formula 8)
Is preferable.
In Embodiment 3 or 4, when the electrode spacing is 2 mm or less, the outer diameter of the electrode shaft is D1, the outer diameter of the cylindrical conductor is D2, and the length of the cylindrical conductor in the electrode axis direction is D3,
2.0 ≦ D2 / D1 ≦ 5.0 (Formula 9)
D3 / D1 ≦ 9.0 (Formula 10)
Is preferable.

In any case, D1 is approximately determined according to the current value flowing through the electrode, so that the shape of the discharge portion can be optimally set according to the current value, and the startability is further improved.
In the first to fourth embodiments, the discharge medium may be, for example, a metal halide sealed in addition to mercury and a rare gas.

  The discharge lamp may be either DC lighting or AC lighting. When compared with the conventional performance, AC lighting can obtain a greater effect with respect to startability and arc stability. In the case of direct current lighting, the polarity of the input voltage may be reversed depending on the lighting time and the number of lighting times. For example, if the polarity is reversed every 100 hours of lighting, the deterioration of the electrode is not biased to the electrode on one side, so that the objectivity of the light emitting part is improved and the lamp life is improved.

  In the first to fifth embodiments, the electrode material tungsten should have a smaller content of impurities such as potassium, silicon, and aluminum. Since these impurities react with halogens such as bromine to inhibit the halogen cycle, the lamp life is reduced. Further, when there are many impurities, the melting point of tungsten is lowered, so that the electrode is liable to deteriorate. Therefore, these contents are each preferably 10 ppm or less.

An electrode material other than pure tungsten may be used. For example, in order to improve the startability of the lamp, a material obtained by adding a doping material such as thorium to tungsten may be used.
The heat dissipating conductor is not limited to a coil shape. For example, it may be a cylindrical metal conductor surrounding the electrode shaft, and similarly, the heat dissipation of the electrode shaft can be improved.

The heat dissipating conductor and the discharge part may be either in contact or non-contact. If the electrode and the heat dissipating conductor are completely separate, good starting performance can be obtained.
The main electrode and the heat radiating conductor may be made of different materials. For example, the main electrode is pure tungsten having a very high melting point, and the discharge conductor is tungsten containing a relatively large amount of a doping material such as potassium in consideration of the ease of coil formation. What is necessary is just to select an optimal thing according to a use in consideration of workability etc.

Although the discharge lamp has been described as a target shape, the length of the sealing portion and the metal foil may be different, or a pair of electrodes may be arranged so as to be biased in any direction.
FIG. 10 is a configuration example showing the first embodiment of the light source device of the present invention. In FIG. 10, 131 is a lamp, 132 is a concave mirror, and 133 is a light source device of the present invention.

  The lamp 131 is the same as the discharge lamp shown in FIG. 1 a, and a base 135 serving as a holding means is provided on one sealing portion 134. The base 135 is fixed by filling a heat-resistant adhesive 136 in a gap with the sealing portion 134. The sealing part 134 on the side where the base 135 is provided is inserted into the lamp insertion part 137 of the concave mirror 132 and is filled and fixed with a heat-resistant adhesive 136. The base 135 is preferably made of brass having good thermal conductivity. Further, a ceramic or glass discharge lamp holding member may be used instead of the base. By providing the base 135, the heat capacity and surface area of the tip increase, and the temperature rise due to heat conduction from the arc tube is mitigated. Therefore, the metal foil can be shortened, and the entire lamp can be shortened.

  The concave mirror 132 is a parabolic mirror or an elliptical mirror. A reflective coating 138 made of a dielectric multilayer film is formed on the inner surface of the concave mirror 132, and reflects light emitted from the lamp 131 in a predetermined direction with high reflectivity. Since this concave mirror 132 has a large solid angle with respect to the light emitting part of the lamp 131, there is an advantage that the condensing rate can be increased.

  One end of the extension conducting wire 139 is connected to the external conducting wire 140, and the other end is taken out of the concave mirror 132 from the conducting wire extraction hole 141 of the concave mirror 132. The lamp 131 can be started by applying a predetermined voltage between the extension lead 139 and the external lead 142.

As described above, since the lamp 131 has good arc stability, it is possible to obtain an illumination light beam with little flicker and stable brightness.
Similar effects can be obtained by using the discharge lamp of the present invention shown in FIGS. 2a, 4a, 7a, and 8a as the lamp.

  As described above, according to the configuration of the present invention, in the light source device in which the discharge lamp and the concave mirror are integrated, by using the discharge lamp of the present invention, an illumination light beam with good startability and stable brightness can be obtained. A light source device can be realized.

  FIG. 11 is a configuration example showing a second embodiment of the light source device of the present invention. In FIG. 11, 151 is a lamp, 152 is a concave mirror, 153 is a front glass, and 154 is a light source device of the present invention.

  The lamp 151 has the same configuration as the discharge lamp shown in FIG. The concave mirror 152 is an ellipsoidal mirror or a parabolic mirror. The lamp 151 is inserted into the lamp insertion portion 163 on the side where the base 162 is attached, and the center of the light emitting portion formed between the electrodes 155 and 156 is disposed so as to substantially coincide with the first focal point 157 of the concave mirror. The adhesive 158 is fixed.

The front glass 153 is made of Pyrex (registered trademark) glass having excellent heat resistance and translucency, and is fixed to the exit side opening of the concave mirror 152 with a silicon-based adhesive 159.
A coating 160 that reflects ultraviolet light and transmits visible light is provided on the incident surface of the front glass 153 so that harmful ultraviolet light emitted from the lamp 151 does not leak to the outside. By providing the front glass 153 at the exit side opening of the concave mirror 152, a substantially sealed space is formed inside the concave mirror 152, so that even if the lamp 151 is broken, the fragments are scattered outside. This improves the safety of the light source device 154.

  A reflective coating 161 formed of a dielectric multilayer film is applied to the inner surface of the concave mirror 152. Here, a collection range of light emitted from the center of the light emitting portion of the lamp 151, specifically, the center between the electrodes 155 and 156 and incident on the effective reflecting surface of the concave mirror 152 is α. In the lamp 151, since the tips of the electrodes 155 and 156 are tapered, the radiated light within the condensing range α is not blocked by the electrodes 155 and 156. Therefore, there is an advantage that the light emitted from the lamp 151 can be used effectively and the light use efficiency is improved.

Since the condensing range α varies depending on the shape of the concave mirror 152, the condensing range α may be appropriately set so that the taper angle θ of the electrodes 155 and 156 and the diameter φ of the tip end portion satisfy Expressions 1 and 2.
The same effect can be obtained by using the discharge lamp shown in FIGS. 7 a and 8 a as the lamp 151. In that case, the electrode shape may be determined so as to satisfy Equation 3 and Equation 4 or Equation 5 and Equation 6.

  As described above, according to the configuration of the present invention, in the light source device in which the discharge lamp and the concave mirror are integrated, by using the discharge lamp of the present invention, an illumination light beam with good startability and stable brightness can be obtained. A light source device with high light utilization efficiency can be realized.

FIG. 12 is a configuration example showing a third embodiment of the light source device of the present invention. In FIG. 12, 170 is a discharge lamp, and 181 is a concave mirror.
In the discharge lamp 170, the sealing portion 171 in which the short metal foil 173 is sealed is inserted into the insertion hole 182 of the concave mirror 181, so that the center between the focal position 187 of the concave mirror 181 and the electrodes 175 and 176 of the lamp 170 approximately coincide. And fixed with an adhesive 185. As the adhesive 185, an inorganic heat resistant adhesive such as Sumiceram is used.

  The extended conducting wire 186 has one end connected to the external conducting wire 178 of the discharge lamp 170 and the other end drawn out from the conducting wire extraction hole 183 of the concave mirror 181. The gap between the lead extraction hole 183 and the extension lead 186 is filled with an adhesive 185.

  By applying a predetermined voltage to the extended conducting wire 186 and the external conducting wire 177, arc discharge is generated between the electrodes 175 and 176, and light emission specific to the mercury 170a can be obtained along with the evaporation of the mercury 170a serving as a discharge medium.

The concave mirror 181 is an ellipsoid, and the first focal point F1 is 15 mm, and the second focal point F2 (not shown) is 140 mm. In general, an elliptical surface has two elliptical axes (long axis and short axis). The lengths of the major axis and the minor axis can be expressed by the following equations, respectively.
Length of major axis = f1 + f2 (Formula 11)
Length of minor axis = 2 × (f1 × f2) ^1/2 (Formula 12)
The ellipse axis including the first focus F1 and the second focus F2 is the major axis, and the ellipse axis perpendicular to this is the minor axis. The major axis and minor axis length of the ellipsoidal mirror in FIG. 12 are 155 mm and 91.7 mm, respectively. In the case of an ellipsoidal mirror, if the metal foil 174 is too long, it becomes closer to the second focal point, that is, the condensing position, so that the temperature of the metal foil 174 increases conversely. Therefore, the length of the metal foil 174 is such that the distance from the vertex on the lamp insertion portion 182 side of the elliptical surface to the end of the long metal foil 174 on the concave mirror opening side is ½ of the major axis length of the elliptical surface. The settings are as follows.

The inner surface of the concave mirror 181 is provided with a reflective coating 184 made of a dielectric multilayer film, and efficiently reflects light emitted from between the electrodes 175 and 176 of the discharge lamp 170 in a predetermined direction.
The concave mirror is not limited to the ellipsoidal mirror, but a parabolic mirror or the like may be used. However, since the ellipsoidal mirror has a larger solid angle with respect to the light emitting part of the lamp, the light collection rate can be increased.

  According to FIG. 12, since the sealing portion 171 in which the short metal foil 173 of the discharge lamp 170 is sealed is fixed to the insertion hole 182 of the concave mirror 181, the amount of projection of the lamp from the insertion hole 182 to the rear is reduced, and the light source device Can be miniaturized. The sealing part 171 can obtain a sufficient heat capacity and surface area by contacting the concave mirror 181. Therefore, the temperature rise due to heat conduction from the arc tube 170 can be suppressed, and even if the short metal foil 173 is sealed, it is not disconnected by oxidation. On the other hand, since the metal foil 174 that is longer than the metal foil 173 and has a sufficient length is sealed in the sealing portion 172 on the opening side of the concave mirror, it is not disconnected by oxidation.

The discharge lamp 170 may have a sealing part 171 provided with a base or the like.
As described above, according to the configuration of the present invention, a highly reliable and compact light source device can be configured by fixing the sealing portion in which the short metal foil of the discharge lamp is sealed to the concave mirror.

  FIG. 13 is a configuration example showing a fourth embodiment of the light source device of the present invention. In FIG. 13, 191 is a front glass as a translucent sealing means, 192 is nitrogen gas, and the other configuration is the same as FIG.

  The front glass 191 is Pyrex (registered trademark) glass that has excellent heat resistance and is relatively inexpensive, and is fixed to the opening on the reflected light emitting side of the concave mirror 181 with an adhesive 193 such as silicon resin. By providing the front glass 191, a sealed space is formed inside the concave mirror 181, and even when the discharge lamp 170 is broken during lighting, it is possible to prevent the fragments from scattering to the outside.

  A reflection coating for removing ultraviolet rays and infrared rays may be provided on at least one of the light incident side and the light emitting side of the front glass 191. Thereby, it can prevent that an ultraviolet-ray and infrared rays radiate | emit outside. Further, if antireflection coating is applied to at least one of the planes, the emitted light of the discharge lamp 170 can be emitted efficiently.

  Nitrogen gas 192 is sealed in the sealed space formed inside the concave mirror 181. The nitrogen gas 192 may be sealed by, for example, performing the bonding operation of the concave mirror 181 and the front glass 191 after fixing the discharge lamp 170 in a glove box filled with the nitrogen gas 192. Instead of the nitrogen gas 192, an inert gas such as argon gas may be used.

According to FIG. 13, since the sealed space formed inside the concave mirror 181 is filled with the nitrogen gas 192, oxidation of the metal foil 174 on the opening side of the concave mirror 181 can be prevented.
The concave mirror 181 may be an ellipsoidal mirror, a rectangular mirror, or the like. However, since the ellipsoidal mirror has a large solid angle with respect to the light emitting part of the lamp, the condensing rate can be increased. In addition, since the depth of the concave mirror 181 in the optical axis direction can be increased, this is suitable when a front glass 191 is disposed to form a sealed structure.

The discharge lamp 170 may have a sealing part 171 provided with a base or the like.
In the present embodiment, an example in which a lamp having a different metal foil length is used as the discharge lamp has been described. However, the above effect can be obtained regardless of the length of the metal foil.

  As described above, according to the present invention, the front glass 191 is used to form a sealed space inside the concave mirror 181, and the inert gas such as nitrogen gas 192 is sealed in the sealed space, thereby oxidizing the metal foil. Therefore, a highly reliable light source device can be configured.

  FIG. 14 is a configuration example showing a fifth embodiment of the light source device of the present invention. In FIG. 14, 201 is an argon gas, and other configurations are the same as those of the embodiment of FIG.

  A difference from the embodiment of FIG. 13 is that an argon gas 201 of 30 atm is enclosed in a sealed space inside the concave mirror 181. In general, the discharge lamp has a very high pressure inside the arc tube during the lighting operation, and the pressure difference from the outside of the arc tube becomes very large.

  According to FIG. 14, the pressure inside the arc tube during the lighting operation of the discharge lamp 170 is about 10 MPa (megapascal), but since 30 atmospheres of argon gas 201 is sealed in the sealed space, the inside and outside of the arc tube And the risk of the arc tube breakage is greatly reduced. Further, similarly to the effect of FIG. 13, the argon gas prevents the metal foil 174 from being oxidized, so that the metal foil is not disconnected and the reliability of the light source device is improved.

  The concave mirror 181 may be an ellipsoidal mirror, a rectangular mirror, or the like. However, since the ellipsoidal mirror has a large solid angle with respect to the light emitting part of the lamp, the condensing rate can be increased. In addition, since the depth of the concave mirror 181 in the optical axis direction can be increased, this is suitable when a front glass 191 is disposed to form a sealed structure.

  Instead of argon gas, an inert gas such as nitrogen may be sealed at a predetermined pressure, and the same effect can be obtained. Further, even when air is sealed at a predetermined pressure, the effect of preventing oxidation is lost, but the risk of breakage of the arc tube can be greatly reduced.

The pressure of the gas to be sealed may be not less than 1 atm and not more than the pressure in the arc tube when the discharge lamp is turned on.
The discharge lamp 170 may have a sealing part 171 provided with a base or the like.

In the present embodiment, an example in which a lamp having a different metal foil length is used as the discharge lamp has been described. However, the above effect can be obtained regardless of the length of the metal foil.
As described above, according to the present invention, a sealed space is formed inside the concave mirror using the front glass, and light is emitted by enclosing a gas having a pressure of 1 atm or more and a pressure within the arc tube at the time of lighting in the sealed space. The tube can be prevented from bursting and a highly reliable light source device can be configured.

FIG. 15 is a configuration example showing a sixth embodiment of the light source device of the present invention. In FIG. 15, reference numeral 210 denotes a discharge lamp, and 221 denotes a concave mirror.
The discharge lamp 210 is an AC-lighted ultra-high pressure mercury lamp, and the operating pressure during lighting is 10 MPa (megapascal) or more. Therefore, a front glass is provided at the opening of the concave mirror in order to prevent scattering of the glass pieces at the time of breakage. In the discharge lamp 210, the sealing portion 211 in which the short metal foil 213 is sealed is inserted into the insertion hole 222 of the concave mirror 221, and the center between the first focal point 227 of the concave mirror 221 and the electrodes 215 and 216 of the lamp 210 approximately coincides. The position is adjusted in this way, and it is fixed with an adhesive 225. As the adhesive 225, an inorganic heat resistant adhesive such as Sumiceram is used.

  One end of the extended conductor 226 is connected to the external conductor 218 of the discharge lamp 210, and the other end is drawn out from the conductor extraction hole 223 of the concave mirror 221. The gap between the lead extraction hole 223 and the extension lead 226 is filled with the adhesive 225.

By applying a predetermined voltage to the extended conducting wire 226 and the external conducting wire 217, an arc discharge is generated between the electrodes 215 and 216, and light emission specific to the mercury 210a can be obtained along with the evaporation of the mercury 210a as a discharge medium.
The concave mirror is an ellipsoidal mirror, and the length of the metal foil 214 is from the top of the ellipsoidal lamp insertion part 222 side to the concave mirror opening side of the long metal foil 214 as in the third embodiment (FIG. 12). The distance to the end is set to be ½ or less of the major axis length of the ellipsoid.

The inner surface of the concave mirror 221 is provided with a reflective coating 224 made of a dielectric multilayer film, and efficiently reflects light emitted from between the electrodes 215 and 216 of the discharge lamp 210 in a predetermined direction.
According to FIG. 15, since the sealing portion 211 in which the short metal foil 213 of the discharge lamp 210 is sealed is fixed to the insertion hole 222 of the concave mirror 221, the amount of protrusion of the lamp from the insertion hole 222 to the rear is reduced, and the light source device Can be miniaturized. A sufficient heat capacity and surface area can be obtained by connecting the sealing portion 211 to the concave mirror 221. Therefore, the temperature rise due to heat conduction from the arc tube can be suppressed, and even if the short metal foil 213 is sealed, it is not broken by oxidation. On the other hand, when the front glass 231 is disposed at the opening of the concave mirror 221, the temperature inside the concave mirror 221 is higher than when the front glass 231 is not disposed, and thus the temperature rise of the metal foil 214 is increased. Since the metal foil 214 having a length sufficiently longer than the metal foil 213 is sealed in the sealing portion 212 on the part side, it is not disconnected by oxidation.

The concave mirror 221 is not limited to an ellipsoidal mirror, and a parabolic mirror or the like may be used. However, since the ellipsoidal mirror has a larger solid angle with respect to the light emitting part of the lamp, the light collection rate can be increased. Further, since the depth of the concave mirror 221 in the optical axis direction can be increased, it is suitable when a front glass is arranged to form a sealed structure.
Making the metal foil 213 on the lamp insertion part 222 side of the concave mirror 221 shorter than the metal foil 214 on the opening side as in the present embodiment is an extremely effective means for reducing the size of the light source.

The inside of the concave mirror does not need to be completely sealed, and a vent for cooling the discharge lamp and the concave mirror may be provided in the concave mirror or a part of the front glass.
The discharge lamp 210 may have a sealing part 211 provided with a base or the like. As described above, according to the configuration of the present invention, a highly reliable and compact light source device can be configured by fixing the sealing portion in which the short metal foil of the discharge lamp is sealed to the concave mirror.

  FIG. 16 is a configuration example showing an embodiment of the projection display device of the present invention. In FIG. 16, 240 is a light source, 241 is a UV-IR cut filter, 242 is a field lens, 243 is a liquid crystal panel, and 244 is a projection lens.

The light source 240 is the same as the light source device shown in FIG. 15, and a description of the specific configuration is omitted.
The light emitted from the light source 240 is removed of ultraviolet and infrared components by the UV-IR cut filter 241, passes through the field lens 242, and then enters the liquid crystal panel 243. The field lens 242 collects the light that illuminates the liquid crystal panel 243 on the projection lens 244. The liquid crystal panel 243 modulates the transmittance of incident light according to the video signal, and forms an optical image on the liquid crystal panel 243. The light transmitted through the liquid crystal panel 243 enters the projection lens 244, and the projection lens 244 enlarges and projects an optical image on the liquid crystal panel 243 on a screen (not shown).

According to FIG. 16, since the light source device shown in FIG. 15 is used as the light source 240, the reliability of the projection display device is improved and the entire device can be miniaturized.
In the present embodiment, an example in which the light source device shown in FIG. 15 is used as the light source 240 is shown. However, even if the light source device shown in any of FIGS. 10 to 14 is used, reliability is improved and the device is downsized. An effect is obtained. In particular, if the light source device of FIG. 11 is used, the emitted light of the lamp can be collected more efficiently, so that the brightness of the projection display device can be increased.

  Between the light source 240 and the field lens 242, an optical element for efficiently or uniformly guiding the light emitted from the light source 240 to the liquid crystal panel 243, for example, a lens array or a polarization conversion element may be disposed.

  In addition, an example in which only one transmissive liquid crystal panel using polarized light is used as a spatial light modulation element has been shown. For example, a liquid crystal panel using three transmissive liquid crystal panels, a liquid crystal panel using scattering, Alternatively, a spatial light modulator that forms an optical image corresponding to a video signal as a change in diffraction, reflection, or the like may be used. Similar effects can be obtained as long as the light illuminated by the light source is modulated to form an optical image.

Further, a rear projection type display apparatus may be configured using a transmission type screen.
As described above, according to the present invention, a light source device of the present invention is used as a light source in a projection display device that illuminates a spatial light modulator such as a liquid crystal panel with a light source and projects an optical image on the spatial light modulator. By using it, a compact and bright projection display device can be constructed.

(A) is a schematic block diagram which shows 1st Embodiment of the discharge lamp of this invention, (b) is an enlarged view of the electrode structure of 1st Embodiment. (A) is a schematic block diagram which shows 2nd Embodiment of the discharge lamp of this invention, (b) is an enlarged view of the electrode structure of 2nd Embodiment. It is an enlarged view of the other electrode structure of 2nd Embodiment. (A) is a schematic block diagram which shows 3rd Embodiment of the discharge lamp of this invention, (b) is an enlarged view of the electrode structure of 3rd Embodiment. It is an enlarged view of the other electrode structure of 3rd Embodiment. It is an enlarged view of other electrode structure of a 3rd embodiment. (A) is a schematic block diagram which shows 4th Embodiment of the discharge lamp of this invention, (b) is an enlarged view of the electrode structure of 4th Embodiment. (A) is a schematic block diagram which shows 5th Embodiment of the discharge lamp of this invention, (b) is an enlarged view of the electrode structure of 5th Embodiment. It is a characteristic view which shows the relationship between a taper angle and a rise time. It is a schematic block diagram which shows 1st Embodiment of the light source device of this invention. It is a schematic block diagram which shows 2nd Embodiment of the light source device of this invention. It is a schematic block diagram which shows 3rd Embodiment of the light source device of this invention. It is a schematic block diagram which shows 4th Embodiment of the light source device of this invention. It is a schematic block diagram which shows 5th Embodiment of the light source device of this invention. It is a schematic block diagram which shows 6th Embodiment of the light source device of this invention. 1 is a schematic configuration diagram showing an embodiment of a projection display device of the present invention. It is a schematic block diagram which shows the structure of the conventional discharge lamp. It is a schematic block diagram which shows the electrode structure of the conventional discharge lamp. It is a schematic block diagram which shows the other electrode structure of the conventional discharge lamp. It is a schematic block diagram which shows the further another electrode structure of the conventional discharge lamp. (A) is a schematic block diagram which shows the structure of the conventional light source device, (b) is an expanded sectional view of the cross section A of Fig.21 (a).

Explanation of symbols

10, 101, 170 Arc tube 11, 12, 102, 103, 134, 171, 172, 211, 212 Sealing part 13, 14, 173, 174, 213, 214 Metal foil 15, 16, 41, 42, 45, 61, 62, 66, 81, 82, 106, 107, 155, 156, 175, 176, 215, 216 Electrode 15a, 16a, 41a, 42a, 61a, 62a, 66a, 68a, 81a, 82a, 106a Electrode shaft 15b , 16b, 41b, 42b, 45b, 106b Discharge parts 17, 18, 65, 85, 112 Radiating conductors 19, 20, 108, 140, 142, 177, 178, 217, 218 External conductors 21, 22 Discharge media 31, 51 71, 91, 121, 170, 210 Discharge lamps 41c, 42c, 45c, 81c, 82c, 106c, 10 7c Taper 61b, 62b, 66b, 68b, 81b, 82b Cylindrical conductor 67 Taper 132, 152, 181, 221 Concave mirror 135, 162 Holding means 137, 163, 182, 222 Lamp insertion part 153, 191, 231 Translucent sealing Means 243 Spatial light modulation element

Claims (18)

Arc tube forming a discharge space, sealing portions formed at both ends of the arc tube,
The metal foil sealed in the sealing part, one end connected to the metal foil, the other end connected to the inside of the arc tube, the other end connected to the metal foil, An outer conductor with the other end protruding outside the sealing portion, and a discharge medium sealed in the arc tube,
The discharge lamp according to claim 1, wherein the metal foils have different lengths. 2. The discharge lamp according to claim 1, wherein the discharge medium contains an inert gas and mercury. 2. The discharge lamp according to claim 1, wherein the arc tube is made of quartz glass or sapphire glass. 2. The discharge lamp according to claim 1, further comprising a holding unit in a sealing portion in which a short metal foil is sealed. 5. The discharge lamp according to claim 4, wherein the holding means is made of metal. The discharge lamp according to claim 1, and a concave mirror that reflects light emitted from the discharge lamp from a predetermined direction,
In the discharge lamp, a sealing portion in which a short metal foil is sealed is fixed to the concave mirror. A discharge lamp, and a concave mirror that reflects light emitted from the discharge lamp in a predetermined direction,
The discharge lamps have different lengths of metal foil sealed in sealing portions provided at both ends of the arc tube,
The concave mirror has an opening from which reflected light is emitted, and a lamp insertion part provided on the opposite side of the opening,
In the discharge lamp, a sealing portion in which a short metal foil is sealed is inserted into the lamp insertion portion, and the center of the light emitting region formed in the arc tube is approximately the focal point on the short side of the concave mirror. A light source device characterized by being arranged to match. A discharge lamp;
A concave mirror that reflects light emitted from the discharge lamp in a predetermined direction;
A translucent sealing means disposed in the opening on the reflected light exit side of the concave mirror to form a sealed space inside the concave mirror;
An inert gas is sealed in the sealed space. A discharge lamp;
A concave mirror that reflects light emitted from the discharge lamp in a predetermined direction;
A translucent sealing means disposed in the opening on the reflected light exit side of the concave mirror to form a sealed space inside the concave mirror;
A light source device, wherein gas is sealed in the sealed space at a pressure higher than 1 atm and lower than an operating pressure of the discharge lamp. A discharge lamp having an operating pressure of 10 MPa (megapascal) or more;
A concave mirror that reflects light emitted from the discharge lamp in a predetermined direction;
A translucent sealing means,
The discharge lamps have different lengths of metal foil sealed in sealing portions provided at both ends of the arc tube,
The concave mirror has an opening from which reflected light is emitted, and a lamp insertion part provided on the opposite side of the opening,
In the discharge lamp, a sealing portion in which a short metal foil is sealed is inserted into the lamp insertion portion, and the center of the light emitting region formed in the arc tube is approximately the focal point on the short side of the concave mirror. Arranged to match,
The light source device, wherein the sealing means is disposed in the opening of the concave mirror. The light source device according to claim 8 or 9, wherein the translucent sealing means is Pyrex (registered trademark) glass. The light source device according to claim 8 or 9, wherein the translucent sealing means is provided with a coating for reflecting at least one of infrared rays and ultraviolet rays. 10. The light source device according to claim 8, wherein the translucent sealing means is provided with an antireflection coating for preventing reflection of incident light. 10. The light source device according to claim 8 or 9, wherein the discharge lamp is the discharge lamp according to claim 1, and a sealing portion in which a metal foil having a short length is sealed is fixed to the concave mirror. 10. The light source device according to claim 8, wherein the concave mirror is an ellipsoidal mirror. 10. The light source device according to claim 8, wherein the discharge lamp has an operating pressure of 10 MPa (megapascal) or more. The concave mirror is an ellipsoidal mirror, characterized in that the distance from the apex of the ellipsoidal lamp side to the end of the long metal foil on the concave mirror opening side is 1/2 or less of the major axis length of the ellipsoidal surface. The light source device according to claim 7 or 10. A light source;
A spatial light modulator that is illuminated by the light source and forms an optical image in accordance with a video signal;
A projection display comprising: a projection unit that projects an optical image formed on the spatial light modulation element onto a screen; and the light source is the light source device according to any one of claims 6 to 17. apparatus.

Images