JP2005190711A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device in which requirements for "improvement of brightness", "obtaining a pointed light source", and "high-definition" can be met, while rising of temperatures at the light emitting part is suppressed. <P>SOLUTION: In an ultra-high pressure discharge lamp 14, an electrode 40 composed of an anode 40a and a cathode 40b is installed inside a light emitting part 28, while a sealing part 30 on the side of the anode 40a is mounted on the mounting bore 42 of a reflector 16. Accordingly, this means that the cathode 40b having a luminescent spot is located on the forward side of the light emitting direction of the reflector 16, thus the influence of blinking light due to the movement of the luminescent spot on the quality of the picture on the screen can be reduced. Furthermore, in the case the center of the arc moves due to consumption of the anode 40a, the major part of the light reflected by the reflecting face 16a becomes to be directed toward a direction separating from the light emitting part 28. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a light source device that includes an ultrahigh pressure discharge lamp and a reflector and is used as a light source of a projection type projector.

  In recent years, projection projectors have been used in various scenes, such as business presentations, home theaters and rear projection televisions in the home, and the light source device that is the main component is commonly used with a discharge lamp attached to a reflector. It has been.

There is a strong demand for “brightness improvement” in such a light source device for a projection type projector. Conventionally, this demand has been met by increasing the pressure of the discharge lamp (enclosing mercury of 0.15 mg / mm ³ or more). . However, a DC lighting type discharge lamp having a bright spot on the cathode side has not been adopted because of concerns about screen unevenness, and an increase in the pressure of the AC lighting type discharge lamp has been promoted exclusively.

  In the prior art, an AC lighting type discharge lamp responded to the demand for “brightness improvement” by increasing the mercury vapor pressure. However, the downsizing of the image element accompanying the downsizing of the projector in recent years has led to the light source device. It was required to be “a point light source” as much as possible, and an AC lighting type discharge lamp could not meet this requirement.

  On the other hand, in order to meet the requirement of being a point light source, it is optimal to use a DC lighting type discharge lamp having a bright spot on the cathode side. It is known that “brightness improvement” can be achieved by increasing the brightness. However, when a DC lighting type ultra-high pressure discharge lamp is used, the above-mentioned problem of screen unevenness remains, so that the demand for “high image quality” cannot be met.

  In addition, when the cathode side of a DC lighting ultra-high pressure discharge lamp is installed in the mounting hole provided in the center of the reflector, the arc center moves away from the inner surface of the reflector due to anode consumption and cathode deposition. Most of the light reflected by the reflecting surface of the reflector comes into contact with the light emitting part of the ultra high pressure discharge lamp. For this reason, the temperature of the light emitting part is increased, and there is a possibility that the illuminance lowering or bursting of the ultra high pressure discharge lamp may occur in a short time.

  Therefore, the main object of the present invention is to meet all the requirements of “brightness improvement”, “being a point light source” and “high image quality”, and by suppressing the temperature rise of the light emitting part. An object of the present invention is to provide a light source device that can prevent a decrease in illuminance and explosion in a short time.

According to the first aspect of the present invention, an electrode 40 composed of an anode 40a and a cathode 40b is disposed in a light emitting section 28 in which mercury of 0.15 mg / mm ³ or more is sealed. Light emitted from the light emitting unit 28 and the direct-current lighting type ultra-high pressure discharge lamp 14 extending in a rod shape from the part and having two sealing parts 30 formed therein, and the mounting hole 42 through which one of the sealing parts 30 is inserted The light source device 10 ”includes a reflector 16 having a reflective surface 16 a that reflects the light and the sealing portion 30 on the anode 40 a side of the ultrahigh pressure discharge lamp 14 is attached to the attachment hole 42 of the reflector 16.

  In the DC lighting type ultrahigh pressure discharge lamp 14, the cathode 40 b of the electrode 40 becomes a bright spot. In the present invention, the sealing portion 30 on the anode 40 a side of the ultrahigh pressure discharge lamp 14 is attached to the attachment hole 42 of the reflector 16. Therefore, the bright spot of the ultra-high pressure discharge lamp 14 is arranged on the front side of the light emitting direction of the reflector 16. Accordingly, the distance from the bright spot to the reflecting surface 16a of the reflector 16 can be increased, and the influence of flicker due to the movement of the bright spot on the image quality of the screen 64 can be reduced. The direction in which the arc center moves due to the exhaustion of the anode 40a in the ultra high pressure discharge lamp 14 is a direction closer to the inner surface of the central portion of the reflector 16, and most of the light reflected by the reflecting surface 16a goes away from the light emitting portion 28. It becomes like this. Thereby, heating of the light emission part 28 by reflected light is suppressed.

  The invention described in claim 2 is the “light source device 10” described in claim 1, wherein “the pulse superimposing device 26 for superimposing the pulse current on the lamp current applied to the ultrahigh pressure discharge lamp 14” is provided. Features.

  In this invention, since the pulse current is superimposed on the lamp current, the temperature of the bright spot is periodically increased by the superimposed pulse current, and before the bright spot moves to another position, Electron emission becomes good, and as a result, the movement of the bright spot is suppressed, and the flickering of the screen is suppressed. When the pal current is superimposed, deposition occurs on the cathode 40b and the movement of the arc center increases, but as described above, most of the light reflected by the reflecting surface 16a is directed away from the light emitting portion 28. Therefore, heating of the light emitting unit 28 by reflected light is not promoted.

  The invention described in claim 3 is the "light source device 10" described in claim 1 or 2, wherein "the light source device 10" extends to the light emitting portion 28 side over the central portion so as to cover the sealing portion 30 on the anode 40a side. And a heat conducting member 18 made of an oxide sintered body formed in this manner.

  In the present invention, since the heat conducting member 18 is formed extending from the front end of the sealing part 30 to the light emitting part 28 side beyond the central part, the heat of the ultrahigh pressure discharge lamp 14 is transferred from the sealing part 30 to the heat conducting member 18. It is efficiently escaped to the outside space through.

  The invention described in claim 4 is characterized in that, in the “light source device 10” described in any one of claims 1 to 3, “the reflector 16 is made of metal”.

  In this invention, since the metal reflector 16 having a high thermal conductivity is used, the heat in the reflector 16 can be efficiently released. Further, when the metal reflector 16 is irradiated with light, the reflector 16 is negatively charged by the photoelectric effect, so that cations of impurities (hydrogen, sodium, etc.) generated in the ultrahigh pressure discharge lamp 14 are applied to the reflector 16. It is drawn, passes through the glass wall, and is discharged to the outside of the ultrahigh pressure discharge lamp 14. Therefore, the shortening of the life of the ultrahigh pressure discharge lamp 14 due to impurities can be suppressed.

  The invention described in claim 5 is characterized in that, in the “light source device 10” described in claim 4, “the metal reacts with mercury to generate amalgam”.

  In the present invention, the reflector 16 is composed of a metal (aluminum, gold, silver, zinc, cadmium, lead, sodium, potassium, etc.) that reacts with mercury to form an amalgam. Mercury scattered on the surface reacts with the reflector 16 and is fixed as “amalgam”. Therefore, there is no concern that mercury diffuses even when the ultra high pressure discharge lamp 14 is ruptured.

  According to the invention described in claims 1 to 5, since the sealing portion on the anode side of the ultra high pressure discharge lamp is attached to the attachment hole of the reflector, the distance from the bright spot to the reflection surface of the reflector is increased. And flickering of the screen due to the movement of the bright spot can be suppressed. Further, as the arc center moves due to anode consumption and cathode deposition, the light reflected by the reflecting surface goes in a direction away from the light emitting part of the ultrahigh pressure discharge lamp, so that heating of the light emitting part by the reflected light is suppressed. Therefore, it is possible to prevent the illuminance drop and the burst of the ultra high pressure discharge lamp in a short time.

  Referring to FIG. 1, a light source device 10 to which the present invention is applied is used as a light source of a projection type projector 12 as shown in FIG. 4, and light from an ultrahigh pressure discharge lamp 14 and an ultrahigh pressure discharge lamp 14. The reflector 16, the heat conducting member 18 that releases the heat of the ultra-high pressure discharge lamp 14, the cap 20, the front cover 22, the DC power supply 24, and the pulse superimposing device 26 are included.

As shown in FIG. 3, the ultra-high pressure discharge lamp 14 includes a sealed container 32 having a spherical light emitting portion 28 and a rod-shaped sealing portion 30 extending straight from both ends thereof. And inside each sealing part 30 in the envelope container 32, an electrode bar 34 with one end protruding into the light emitting part 28, a lead bar 36 with one end protruding outside, and the other end of the electrode bar 34, A molybdenum foil 38 that electrically connects the other end of the lead bar 36 is disposed, and a pair of tungsten electrodes (hereinafter simply referred to as “electrodes”) 40 is formed at one end of each electrode bar 34. An anode 40a and a cathode 40b are connected. In addition, 0.15 mg / mm ³ or more of mercury is sealed inside the light emitting unit 28.

  The reflector 16 (FIG. 1) is a bowl-shaped member for reflecting light generated in the light emitting portion 28 of the ultrahigh pressure discharge lamp 14 in a predetermined direction, and a mirror-like reflecting surface 16 a is formed on the inner surface of the reflector 16. Has been. In addition, a cylindrical discharge lamp mounting portion 44 that forms a mounting hole 42 through which the sealing portion 30 on the anode 40 a side of the ultrahigh pressure discharge lamp 14 is inserted is formed at the center of the reflector 16.

  As the material of the reflector 16, glass or metal can be used, but metal (aluminum, stainless steel, brass, nickel, chromium, nickel-chromium alloy, copper, copper- It is desirable to use a nickel alloy or the like. The thermal conductivity of the metallic reflector 16 is much higher than that of the glass reflector 16, for example, 233 W / m · K for aluminum and 19 W / m · K for stainless. Therefore, if the metal reflector 16 is used, the heat generated in the ultrahigh pressure discharge lamp 14 can be efficiently released to the outside.

  In addition, as a processing method of the metallic reflector 16, “press processing” or “drawing” can be used, but when “drawing” is used, the thickness of the reflector 16 is 0.2 mm. It can be made as thin as possible. Further, if a molding process such as “pressing” is performed after “drawing”, it is possible to obtain the reflector 16 having a thin thickness and high processing accuracy.

  The weight of the reflector 16 formed with a thickness of 1.2 mm by “drawing” is about 113 g if it is made of aluminum and about 125 g if it is made of stainless steel. ) Is significantly lighter than the weight of about 250 g.

  The heat conducting member 18 radiates the heat generated in the light emitting portion 28 of the ultra high pressure discharge lamp 14 to the outside. As shown in FIGS. 1, 2 and 3, the heat conducting member 18 on the anode 40a side of the ultra high pressure discharge lamp 14 is provided. A cylindrical heat conducting portion 46 interposed between the outer surface of the sealing portion 30 and the inner surface of the mounting hole 42 in the reflector 16 (that is, the inner surface of the discharge lamp mounting portion 44) and the outer surface of the discharge lamp mounting portion 44 are fitted. It is comprised by the cylindrical fitting part 48 to match | combine, and the cap mounting part 50 which has the annular surface to which the cap 20 is mounted | worn.

  The heat conducting part 46 is formed so as to cover the sealing part 30 on the anode 40 a side of the ultrahigh pressure discharge lamp 14 and extend to the light emitting part 28 side beyond the central part of the sealing part 30. That is, as shown in FIG. 3, when the length of the sealing portion 30 is L (for example, 22.2 mm), the tip position P of the portion (the heat conducting portion 46) that covers the sealing portion 30 of the heat conducting member 18 is sealed. It arrange | positions from the front-end | tip of the stop part 30 to the light emission part 28 side rather than the position of L / 2 (for example, 11.1 mm).

  The heat conducting member 18 is integrally formed of an oxide sintered body such as alumina (Al 2 O 3), steatite (MgO—SiO 2), mullite (3Al 2 O 3 —SiO 2), forsterite (2MgO—SiO 2) or the like. Yes. Therefore, the heat generated in the light emitting portion 28 of the ultrahigh pressure discharge lamp 14 is propagated from the sealing portion 30 to the heat conducting portion 46 of the heat conducting member 18 and is released from the entire surface of the heat conducting member 18 to the external space and the reflector 16. Become. The thermal conductivity of alumina (Al 2 O 3) is 16.7 W / m · K, the thermal conductivity of steatite (MgO—SiO 2) is 2.5 W / m · K, and the thermal conductivity of mullite (3Al 2 O 3 —SiO 2) is The thermal conductivity of 4.2 W / m · K and forsterite (2MgO—SiO 2) is 3.4 W / m · K. However, the heat conducting member 18 may be a sintered body of an oxide having heat resistance and heat conducting properties, and the type and blending ratio of the constituent materials are not particularly limited.

  The cap 20 protects the tip end portion of the sealing portion 30 in the ultra high pressure discharge lamp 14 and holds the lead wire 52 (FIG. 1), and is formed in a mortar shape from ceramic or the like.

  The DC power source 24 applies a lighting start voltage (200 V or more) to the ultra high pressure discharge lamp 14 and supplies a lamp current (eg, 2.86 A) during steady lighting. On the other hand, a pulse current (for example, 3.58 A) having a predetermined pulse width (for example, 10 msec) is superimposed at a predetermined repetition period (for example, 300 Hz). An electric circuit including the DC power supply 24 and the pulse superimposing device 26 is connected to a lead wire 52 extending from the ultrahigh pressure discharge lamp 14.

When assembling the light source device 10, first, as shown in FIG. 3, the heat conducting portion 46 of the heat conducting member 18 is fitted to the outer surface of the sealing portion 30 on the anode 40 a side in the ultrahigh pressure discharge lamp 114. Subsequently, the distal end portion of the heat conducting portion 46 and the outer surface of the sealing portion 30 are joined with cement 54, and the cap 20 is fixed to the cap mounting portion 46 with cement. Then, the super high pressure discharge lamp 14 is positioned at the center of the reflector 16, and the fitting portion 48 and the discharge lamp mounting portion 44 are joined by cement. Thereafter, the DC power supply 24 and the pulse superimposing device 26 are connected to the lead wire 52 extending from the ultrahigh pressure discharge lamp 14.

In the projector 12 in which the light source device 10 is incorporated, as shown in FIG. 4, two fly-eye lenses 56a and 56b, an internal optical system 58, an optical element 60 such as an LCD, DLP, or LCOS, and a projection The lens 62 is disposed at a predetermined position, and the light emitted from the light source device 10 is projected onto the screen 64 through these optical devices.

  That is, when the drive switch of the projector 12 is turned on, the lighting start voltage is applied from the DC power source 24 to the super high pressure discharge lamp 14 and the light emitting unit 28 emits light. The light generated by the light emitting unit 28 is reflected by the reflecting surface 16a of the reflector 16 and applied to the fly-eye lenses 56a and 56b and the internal optical system 58. After receiving image information from the optical element 60, the projection lens 62 Is projected onto the screen 64.

  In this embodiment, the sealing portion 30 on the anode 40a side of the ultra high pressure discharge lamp 14 is attached to the attachment hole 42 of the reflector 16, so that the cathode 40b having a bright spot is the tip of the reflector 16 in the light emitting direction. Will be placed on the side. Therefore, the distance from the bright spot to the reflecting surface 16a of the reflector 16 can be increased, and the influence of flicker due to the movement of the bright spot on the image quality on the screen 64 can be reduced.

  Further, the direction in which the arc center moves due to “depletion of the anode 40a” and “deposition of the cathode 40b” is a direction approaching the inner surface of the central portion of the reflector 16, as shown in FIG. 5, and the light reflected by the reflecting surface 16a. In many cases, as shown in FIG. 6, the light travels away from the light emitting unit 28. Therefore, heating of the light emitting unit 28 by reflected light is suppressed, and combined with the heat dissipation effect of the heat conducting member 18, it is possible to avoid malfunction due to abnormal heating of the ultrahigh pressure discharge lamp 14. Moreover, since the temperature drop after the light is turned off is promoted by the heat dissipation effect of the heat conducting member 18, the waiting time until the light can be turned on again can be shortened.

  In the above-described embodiment, the pulse superimposing device 26 superimposes the pulse current on the lamp current. Therefore, the temperature of the bright spot is periodically increased by the superimposed pulse current, and the bright spot is changed to the other. Before moving to the position, the electron emission at the current position becomes good. As a result, the movement of the bright spot can be suppressed, and the effect of the flicker due to the movement of the bright spot on the image quality on the screen 64 is coupled with the fact that the cathode 40b is arranged on the front side in the light emitting direction of the reflector 16. Can be reduced.

  Moreover, when the metal reflector 16 is employed, the following effects can be obtained. That is, when the light generated in the light emitting unit 28 is irradiated onto the metallic reflector 16, the reflector 16 is negatively charged by the photoelectric effect, so that hydrogen or sodium generated in the light emitting unit 28 of the ultrahigh pressure discharge lamp 14 is used. Impurities such as cations having a small ion radius are attracted toward the reflector 16, pass through the glass wall, and are extracted to the outside of the light emitting unit 28. Thereby, the impurity in the light emission part 28 is reduced, and the lifetime reduction of the ultrahigh pressure discharge lamp 14 by an impurity is suppressed.

  In this case, when a metal (aluminum, stainless steel, gold, silver, zinc, cadmium, lead, sodium, potassium, etc.) that reacts with mercury to generate “amalgam” is adopted as the material of the reflector 16, the ultrahigh pressure discharge lamp 14 is used. Mercury scattered inside the reflector 16 at the time of bursting and the reflector 16 react to generate “amalgam”, so that the diffusion of mercury can be prevented more reliably. In order to obtain “a mercury diffusion preventing effect due to the formation of amalgam”, a metal film that generates “amalgam” may be formed on the reflecting surface 16 a of the reflector 16.

  In the above-described embodiment, as shown in FIG. 3, the heat conducting member 18 having the heat conducting portion 46, the fitting portion 48 and the cap mounting portion 50 is used, but instead of this, FIG. 7 and FIG. As shown in FIG. 8, a heat conducting member 70 in which a cylindrical heat conducting portion 66 and a cap 68 are integrally formed may be used. Further, as shown in FIGS. 9 and 10, a heat conducting member 76 in which a cylindrical heat conducting portion 72 and a cap 74 are joined by cement or the like may be used. As shown in FIG. A heat conducting member 80 composed only of the heat conducting unit 78 may be used.

  Then, as shown in FIG. 12, a heat radiating plate 82 may be attached to each of the heat conducting members 18, 70, 76 and 80, or as shown in FIG. A missing portion 84 may be provided. As shown in FIG. 14, the lacking portion 84 is formed by partially lacking the end portions of the heat conducting portions 46, 66, 72 and 78 facing the light emitting portion 28, or as shown in FIG. These are provided by combining two (or three or more) split cylinders 80a and 80b having different lengths. For example, when the light source device 10 is arranged so that the optical axis is horizontal inside the projector 12, the temperature of the lower part is higher than the temperature of the upper part of the light emitting part 28 due to the convection of the gas in the light emitting part 28. Becomes lower. In such a case, by providing the missing portion 84 at a position corresponding to the lower portion of the light emitting portion 28, heat radiation at the lower portion of the light emitting portion 28, that is, the low temperature portion can be suppressed, and the temperature difference between the upper portion and the lower portion can be reduced. Can be resolved. Thereby, the malfunction of the operation | movement resulting from the temperature difference which arose in the light emission part 28 can be eliminated.

  However, also in these embodiments, the heat conducting members 70, 76 and 80 are sintered oxides, and exceed the central portion (L / 2 portion) of the sealing portion 30 in the ultrahigh pressure discharge lamp 14. Therefore, it is necessary to extend to the light emitting portion 28 side.

It is sectional drawing which shows a light source device. It is a perspective view which shows a heat-conduction member and a cap. It is sectional drawing which shows the joining state of a heat-conduction member and a sealing part. It is a schematic diagram which shows a projector. It is a figure which shows a mode that arc cancellation moves. It is a figure which shows the direction of reflected light. It is sectional drawing which shows another light source device. It is a perspective view which shows the heat conducting member used for the light source device of FIG. It is sectional drawing which shows another light source device. It is a perspective view which shows the heat conducting member used for the light source device of FIG. It is sectional drawing which shows another light source device. It is sectional drawing which shows another light source device. It is a figure which shows the modification of a heat-conduction member. It is a perspective view which shows the heat-conduction member (integral) of FIG. It is a perspective view which shows the heat-conduction member (half-split) of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light source device 12 ... Projector 14 ... Super high pressure discharge lamp 16 ... Reflector 18 ... Heat conducting member 24 ... DC power supply 26 ... Pulse superposition device 28 ... Light emission part 30 ... Sealing part 40 ... Electrode 40a ... Anode 40b ... Cathode 42 ... Installation Hole 44 ... Discharge lamp mounting part 46 ... Heat conduction part

Claims (5)

An electrode composed of an anode and a cathode is disposed in a light emitting part in which mercury of 0.15 mg / mm ³ or more is enclosed, and two sealing parts are formed extending from both ends of the light emitting part in a rod shape. A direct-current lighting type ultra-high pressure discharge lamp, and a reflector having a mounting hole through which one of the sealing portions is inserted and a reflecting surface that reflects light emitted from the light emitting portion,
A light source device in which the sealing portion on the anode side of the ultra-high pressure discharge lamp is attached to an attachment hole of the reflector.   The light source device according to claim 1, further comprising a pulse superimposing device that superimposes a pulse current on a lamp current applied to the ultrahigh pressure discharge lamp.   3. The light source device according to claim 1, further comprising a heat conducting member made of an oxide sintered body formed to extend to the light emitting part side so as to cover the sealing part on the anode side and beyond the central part. .   The light source device according to claim 1, wherein the reflector is made of metal. The light source device according to claim 4, wherein the metal reacts with mercury to generate amalgam.

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