JP2005149968A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To meet all the requirements for "improved brightness", "reduction in weight", "longer life", "shortening of re-lighting time", and "prevention of the spread of mercury". <P>SOLUTION: A light source device 10 comprises: an ultra-high pressure discharge lamp 12 in which 0.15 mg/mm<SP>3</SP>or more of mercury is enclosed; and a reflector 14 of metal having a reflecting surface 14a for reflecting light of the ultra-high pressure discharge lamp 12. Since the reflector 14 of metal is formed thin by drawing or the like, a reduction in weight is achieved without causing a reduction in strength. When the reflector 14 is irradiated with light, the reflector 14 is negatively charged owing to a photoelectric effect. Thereby cations as impurities in the discharge lamp 12 are led out to the outside of the discharge lamp 12. Furthermore, since the reflector 14 has high thermal conductivity, it a drop in temperature after turning-off is accelerated to shorten the latency time until re-lighting. <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 metal 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 main components of the light source device are ultrahigh pressure discharge lamps attached to glass reflectors. Is generally used (Patent Document 1). In such a light source device 1 with a reflector, as shown in FIG. 3, a ceramic cap 3 is attached to an end of the discharge lamp 2, and the discharge lamp 2 and the ceramic cap 3 are made of glass reflector by cement 4. 5 was bonded.

The light source device of such a projection type projector has “brightness improvement”, “light weight”, “long life”, “reduction of relighting time (waiting time until it can be relighted after turning off)”, There is a demand for "preventing mercury diffusion when the discharge lamp ruptures", etc., and conventionally, the demand for "brightness improvement" has been met by increasing the pressure of the discharge lamp (enclosing mercury of 0.15 mg / mm ³ or more). It was.
Japanese Patent No. 3149748

  Conventionally, the demand for "brightness improvement" has been met by increasing the pressure of the discharge lamp, but only by increasing the pressure of the discharge lamp, "weight reduction", "long life", "reduction of relighting time" and We were unable to meet all the requirements of “preventing mercury diffusion”.

  In other words, with regard to “light weight reduction”, measures can be taken by reducing the thickness of the reflector to reduce its weight. However, with a glass reflector, the strength is greatly reduced when the thickness is reduced. There was a possibility that the reflector would be damaged by the fragments when the ruptured.

  In addition, “life extension” is highly dependent on impurities (hydrogen, sodium, etc.) present in the light emitting part of the discharge lamp, but in a light source device using a glass reflector, Impurities supplied from the quartz glass wall into the light emitting part could not be reduced.

  As for “reducing the relighting time”, it is necessary to lower the temperature of the discharge lamp as soon as possible to reduce the internal pressure of the discharge lamp to such an extent that dielectric breakdown can occur. The thermal conductivity of glass reflectors is as low as 1.25 W / m · K for hard glass and 1.53 W / m · K for heat-resistant tempered crystallized glass. The time was getting longer.

  Furthermore, with regard to “preventing mercury diffusion”, measures can be taken by sealing the inside of the reflector and increasing the strength of the reflector to prevent its breakage. Therefore, it is against the demand for “weight reduction”.

  Therefore, the main purpose of the present invention is to meet all the requirements of “brightness improvement”, “weight reduction”, “extension of life”, “reduction of relighting time” and “prevention of mercury diffusion”. It is possible to provide a light source device.

The invention described in claim 1 is “a metal reflector having an ultra-high pressure discharge lamp 12 in which mercury of 0.15 mg / mm ³ or more is sealed and a reflecting surface 14a for reflecting the light of the ultra-high pressure discharge lamp 12. 14 ”.

  In this invention, since the metal reflector 14 is used, weight reduction can be achieved without causing a decrease in strength. Further, when the metal reflector 14 is irradiated with light, the reflector 14 is negatively charged by the photoelectric effect, so that cations of impurities (hydrogen, sodium, etc.) generated in the ultrahigh pressure discharge lamp 12 are applied to the reflector 14. It is drawn, passes through the glass wall, and is discharged to the outside of the ultrahigh pressure discharge lamp 12. Therefore, the shortening of the lifetime of the ultrahigh pressure discharge lamp 12 due to impurities can be suppressed. Moreover, since the metal reflector 14 has high thermal conductivity, it is possible to promote a temperature decrease after the light is turned off, and to shorten the relighting time. Further, since the metallic reflector 14 is not easily damaged, even if the ultrahigh pressure discharge lamp 12 is ruptured, there is no fear that the mercury inside thereof will diffuse.

  The invention described in claim 2 is characterized in that, in the “light source device 10” described in claim 1, “the reflector 14 is made of a metal that reacts with mercury to generate amalgam”.

  In the present invention, the reflector 14 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 14 and is fixed as “amalgam”. Therefore, there is no concern that mercury will diffuse even when the ultra-high pressure discharge lamp 12 is ruptured.

  The invention described in claim 3 is characterized in that, in the “light source device 10” described in claim 1 or 2, “a metal film that reacts with mercury to generate amalgam is formed on the reflective surface 14a”.

  In the present invention, mercury scattered when the ultra-high pressure discharge lamp 12 bursts reacts with the metal film formed on the reflecting surface 14a and is fixed as “amalgam”.

  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, “a visible light reflecting film that promotes reflection of visible light is formed on the reflecting surface 14a”. And

  In the present invention, the visible light reflection film 12 formed on the reflection surface 14a promotes reflection of visible light and improves brightness.

  The invention described in claim 5 is the "light source device 10" described in claim 4, wherein "the visible light reflecting film is a multilayer film having a high refractive index film and a low refractive index film". .

  The present invention relates to a specific configuration of a visible light reflecting film.

  The invention described in claim 6 is characterized in that, in the “light source device 10” described in any one of claims 1 to 5, “the reflector 14 is formed by drawing”.

  In the present invention, the reflector 14 can be formed thin by drawing.

  According to the first to sixth aspects of the invention, since the ultra high pressure discharge lamp is used, it is possible to meet the demand for “brightness improvement”. In addition, since a metal reflector is used, it is possible to meet the demands of “light weight”, “long life”, “reduction of relighting time”, and “prevention of mercury diffusion”.

  According to the second and third aspects of the present invention, mercury scattered at the time of bursting of the ultrahigh pressure discharge lamp can be fixed as an amalgam, so that “diffusion of mercury” can be more reliably prevented.

  According to the invention described in claims 4 and 5, since the visible light reflecting film is formed on the reflecting surface of the reflector, "brightness" can be further increased.

  According to the invention described in claim 6, since the reflector can be formed thin by drawing, the weight can be further reduced.

  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 projector, and includes an ultrahigh pressure discharge lamp 12 and a reflector 14 that reflects light from the ultrahigh pressure discharge lamp 12. The holding member 16 that holds the end portion of the ultra high pressure discharge lamp 12, the cover 18 that covers the front opening of the reflector 14, and the cement 20 for fixing the ultra high pressure discharge lamp 12 and the holding member 16 to the reflector 14. Has been.

The ultra high pressure discharge lamp 12 is a direct current lighting type short arc ultra high pressure mercury discharge lamp, and includes a sealed container 26 having a spherical light emitting portion 22 and a rod-like sealing portion 24 extending straight from both ends thereof. ing. And in each sealing part 24 in the envelope container 26, one end protrudes into the inside of the light emitting part 22, an electrode bar 28 with one end protruding outside, and the other end of the electrode bar 28. A molybdenum foil 32 that electrically connects the other end of the lead bar 30 is disposed, and a pair of tungsten electrodes (hereinafter simply referred to as “electrodes”) 34 is formed at one end of each electrode bar 28. An anode 34a and a cathode 34b are connected. In addition, 0.15 mg / mm ³ or more of mercury is sealed inside the light emitting unit 22.

  The ultra-high pressure discharge lamp 12 shown in FIG. 1 is a double-ended, DC lighting type ultra-high pressure mercury discharge lamp. Instead of this, an AC lighting-type ultra-high pressure mercury discharge lamp, a single-ended type An ultrahigh pressure mercury discharge lamp may be used.

  The reflector 14 is a metal bowl-shaped member for reflecting light generated in the light emitting portion 22 of the ultra high pressure discharge lamp 12 in a predetermined direction. A mirror-like reflecting surface 14 a is formed on the inner surface of the reflector 14. ing. In addition, a cylindrical discharge lamp mounting portion 38 that forms a mounting hole 36 through which the sealing portion 24 of the ultrahigh pressure discharge lamp 12 is inserted is formed at the center of the reflector 14.

  The material of the reflector 14 is not particularly limited as long as it is a metal (aluminum, stainless steel, brass, nickel, chromium, nickel-chromium alloy, copper, copper-nickel alloy, etc.) that can be formed with high strength and a thin wall. It is not a thing. The thermal conductivity of the metallic reflector 14 is much higher than that of a glass reflector, for example, 233 W / m · K for aluminum and 19 W / m · K for stainless steel.

  The holding member 16 holds the leading end portion of the sealing portion 24 in the ultra high pressure discharge lamp 12 and holds the lead wire 40 (FIG. 1), and is integrally formed of a heat resistant material such as ceramic. Yes. The cover 18 seals the inner space of the reflector 14 and is integrally formed of a light-transmitting material such as glass.

  In addition, as a processing method of the reflector 14, “pressing” or “drawing” can be used. When “drawing” is used, as shown in FIG. 2, the thickness of the reflector 14 is increased. Can be reduced to about 0.2 mm. Further, if a molding process such as “pressing” is performed after “drawing”, it is possible to obtain the reflector 14 having a thin thickness and high processing accuracy.

  The weight of the reflector 14 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.

  When assembling the light source device 10, first, the holding member 16 is joined to the end of one sealing portion 24 in the ultrahigh pressure discharge lamp 12 with cement. Subsequently, the ultrahigh pressure discharge lamp 12 is passed through the mounting hole 36 of the reflector 14 to position it in the center of the reflector 14, and the holding member 16 and the sealing portion 24 are attached to the discharge lamp mounting portion 38 of the reflector 14 by the cement 20. Join. Then, the cover 18 is attached to the front opening of the reflector 14. As the “cement”, alumina-silica (Al 2 O 3 —SiO 2), alumina (Al 2 O 3), or silicon carbide (SiC) can be used.

  When the drive switch of the projector is turned on after the light source device 10 is installed inside the projector, the lighting start voltage is applied to the ultrahigh pressure discharge lamp 12 and the light emitting unit 22 emits light. The light generated by the light emitting unit 22 is reflected by the reflecting surface 14a of the reflector 14 and applied to various optical elements. After receiving image information from a digital mirror device or liquid crystal, the light is projected onto the screen by a projection lens. The

  At this time, a large amount of heat is generated together with light in the light emitting portion 22 of the ultra high pressure discharge lamp 12, but the generated heat propagates through the metal reflector 14 having high thermal conductivity and efficiently into the external space. Escaped. Therefore, malfunction due to abnormal heating of the ultra high pressure discharge lamp 12 can be avoided. Further, since the heat is efficiently released, the temperature decrease after the light is turned off is promoted, so that the waiting time until the light can be turned on again can be shortened.

  Further, when the light generated by the light emitting unit 22 is irradiated onto the metallic reflector 14, the reflector 14 is negatively charged by the photoelectric effect, so that hydrogen or sodium generated in the light emitting unit 22 of the ultrahigh pressure discharge lamp 12 is used. Impurities such as cations having a small ion radius are attracted toward the reflector 14, pass through the glass wall, and are extracted to the outside of the light emitting unit 22. Thereby, the impurity in the light emission part 22 is reduced, and the lifetime reduction of the ultrahigh pressure discharge lamp 12 by an impurity is suppressed.

  Further, when the minus side electric circuit in the DC lighting type ultra high pressure discharge lamp 12 is connected to the reflector 14, the reflector 14 is negatively charged. Therefore, in combination with the photoelectric effect described above, impurities (in the light emitting portion 22) Cations) are more effectively extracted to the outside, and the effect of suppressing the shortening of the lifetime is enhanced.

  Further, since the metallic reflector 14 is not easily damaged, there is no concern that mercury will diffuse even when the ultrahigh pressure discharge lamp 12 is ruptured.

  When a metal (aluminum, stainless steel, gold, silver, zinc, cadmium, lead, sodium, potassium, etc.) that reacts with mercury to form “amalgam” is adopted as the material of the reflector 14, ultra-high pressure release is used. Mercury scattered inside the reflector 14 at the time of the rupture of the electric lamp 12 reacts with the reflector 14 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 14 a of the reflector 14.

  Further, since the light source device 10 using the metal reflector 14 is much lighter than the conventional light source device using the glass reflector (FIG. 3), the projector incorporating the light source device 10 is significantly lighter. Can be

  The inventors verified the practicality of the light source device 10 by the following tests 1 to 3.

[Test 1] Test test method for examining the strength of the reflector 14: In the above-described light source device 10 (FIG. 1), the "210W direct current lighting type" super high pressure discharge lamp 12 is adopted, and the "alumina-silica system" The holding member 16 and the sealing portion 24 were fixed to the discharge lamp mounting portion 38 of the reflector 14 using the cement 20. Samples were prepared by changing the “material of the reflector 14”, “thickness of the reflector 14”, and “mercury amount of mercury”.

  On the other hand, in the conventional light source device 1 shown in FIG. 3, a “210 W direct current lighting type” discharge lamp 2 and an “alumina-silica” cement 4 are used, and “the thickness of the reflector 5”. In addition, a comparative sample was prepared by changing the “mercury amount”.

  Then, the presence or absence of breakage of the ultrahigh pressure discharge lamp was examined for each of the three samples and the comparative sample.

  Test results: Table 1 shows whether or not the ultra high pressure discharge lamp is damaged.

  From Table 1, it can be seen that when the metal reflector 14 is used, the occurrence of breakage is greatly reduced as compared with the case where the glass reflector 5 is used.

[Test 2] Test test method for examining the waiting time until relighting can be performed: In the above-described light source device 10 (FIG. 1), the reflector 14 having a “wall thickness of 2.5 mm”, “the amount of mercury enclosed is 0.19 mg / A sample was prepared by adopting a 210 W, ³ mm, direct current lighting type ultrahigh pressure discharge lamp 12 and an “alumina-silica” cement 20 and changing the “material of the reflector 14”.

On the other hand, in the conventional light source device 1 shown in FIG. 3, the discharge lamp 2 of “210 W direct current lighting type with mercury enclosed amount of 0.19 mg / mm ³ ”, the reflector 5 of “wall thickness 6 mm”, and “alumina A “silica-based” cement 4 was employed and used as a comparative sample.

And about each sample and the comparative sample, the waiting time until an ultrahigh pressure discharge lamp can be lighted again under the lighting starting voltage of 1.5 KV and 2.0 KV was investigated.
Test results: Table 2 shows the waiting time until the ultra-high pressure discharge lamp can be relighted (time until “relighting is possible”).

  From Table 2, it can be seen that when the metal reflector 14 is used, the waiting time until relighting can be significantly reduced as compared with the case where the glass reflector 5 is used.

[Test 3] ... Test test method for examining the presence or absence of abnormality of the ultra high pressure discharge lamp 12: In the above-described light source device 10 (FIG. 1), the reflector 14 having a wall thickness of 2.5 mm and made of aluminum, A 300 W, direct current lighting type “high pressure discharge lamp 12” and an “alumina-silica” cement 20 were used as samples, which were 0.19 mg / mm ³ .

On the other hand, in the conventional light source device 1 shown in FIG. 3, the discharge lamp 2 of “300 W direct-current lighting type with a mercury enclosed amount of 0.19 mg / mm ³ ”, the reflector 5 of “wall thickness 6 mm”, and “alumina A “silica-based” cement 4 was employed and used as a comparative sample.

And about each sample and the comparative sample, the maintenance rate of the brightness | luminance of the ultrahigh pressure discharge lamp in predetermined lighting time (The brightness at the time of 0 hours is set to 100) was measured. The lighting method was cycle lighting with a lighting time of 2 hours / light-off time of 15 minutes, and the lighting time was the actual lighting time.
Test results: Table 3 shows the maintenance ratio of the brightness of the ultra-high pressure discharge lamp.

  From Table 3, it can be seen that when the metal reflector 14 is used, the brightness maintenance rate of the ultra-high pressure discharge lamp can be significantly increased as compared with the case where the glass reflector 5 is used.

  In the above-described embodiment, the reflecting surface 14a is configured by finishing the inner surface of the reflector 14 in a mirror shape, and the reflecting surface 14a reflects light. However, a visible light reflecting film is provided on the reflecting surface 14a. The light may be formed and reflected by the visible light reflecting film. In this case, a metal film that reacts with mercury to generate amalgam between the reflecting surface 14a and the visible light reflecting film, an undercoat film that smoothes the reflecting surface 14a, and light other than visible light A light absorbing film that absorbs light may be interposed. When such a light absorption film is interposed, since the reflected light is only in the visible range, a function as a cold reflector is added. In addition, such a light absorbing film may absorb both the infrared region and the ultraviolet region, or may absorb only one of them.

  As the visible light reflecting film, a single layer film made of a metal such as tantalum, nickel, platinum, silver, silver alloy or the like may be used, or a high refractive index film made of TiO2, Ta2O3, ZnS or the like and SiO2, A multilayer film having a low refractive index film made of MgF 2 or the like may be used. Moreover, a laminated film in which these single-layer films and multilayer films are laminated may be used. However, when the single layer film is formed of “silver”, “silver” alone may be used, but those containing impurities such as niobium are more suitable for coating.

Inventors confirmed the effect by a visible light reflective film by the following tests 4-6.
[Test 4]
Test method: In the above-described light source device 10 (FIG. 1), “reflector 14 having a wall thickness of 2.5 mm and made of aluminum”, “210 W with a mercury filling amount of 0.19 mg / mm ³ and a direct current lighting type” The high pressure discharge lamp 12 and the “alumina-silica-based” cement 20 were adopted, and four types of visible light reflecting films were formed on the reflecting surface 14a.

  On the other hand, the light source device 10 in which the visible light reflection film is not formed on the reflection surface 14a was prepared and used as a comparative sample. Other conditions of the comparative sample are the same as those of Samples 1 to 4.

And about each sample, while examining the reflective characteristic of light, the improvement rate of the illumination intensity (brightness) with respect to the comparative sample was investigated.
Test results: The improvement rate of illuminance (brightness) relative to the comparative sample is as shown in Table 4.

  From Table 4, it can be seen that when the visible light reflecting film is formed on the reflecting surface 14a, the illuminance (brightness) can be significantly improved as compared with the case where the visible light reflecting film is not formed.

It is sectional drawing which shows a light source device. It is sectional drawing which shows another light source device (drawing process). It is sectional drawing which shows the conventional light source device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Light source device 12 ... Super high pressure discharge lamp 14 ... Reflector 14a ... Reflecting surface 16 ... Holding member 18 ... Cover 20 ... Cement 22 ... Light emission part 24 ... Sealing part 34 ... Electrode 36 ... Mounting hole 38 ... Discharge lamp attaching part 40 … Lead

Claims (6)

A light source device comprising: an ultrahigh pressure discharge lamp in which 0.15 mg / mm ³ or more of mercury is sealed; and a metal reflector having a reflection surface that reflects light of the ultrahigh pressure discharge lamp. The light source device according to claim 1, wherein the reflector is made of a metal that reacts with mercury to generate amalgam. The light source device according to claim 1, wherein a metal film that reacts with mercury to generate amalgam is formed on the reflection surface. The light source device according to claim 1, wherein a visible light reflection film that promotes reflection of visible light is formed on the reflection surface. The light source device according to claim 4, wherein the visible light reflection film is a multilayer film having a high refractive index film and a low refractive index film. The light source device according to claim 1, wherein the reflector is formed by drawing.

Images