JP2011023150A - Light source device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light source device in which the occurrence of cracking is prevented by suppressing floating of a metal foil 14b provided at a sealing part 12b to which a sub-reflection mirror 3 is fixed and adhered, even if the sub-reflection mirror 3 for returning light emitted from a discharge lamp to a light-emitting part 11 is arranged. <P>SOLUTION: The light source device includes: a discharge lamp comprising the light-emitting part 11 having electrodes 13a, b oppositely disposed in the inside thereof, and sealing parts 12a, b which are formed at both ends of this light-emitting part 11 and have the metal foils 14a, b embedded therein, respectively; a concave reflection mirror 2 mounted on one sealing part 12a so as to surround the discharge lamp; and the sub-reflection mirror 3 comprising a reflection part 31 for returning the light emitted from the discharge lamp to the light-emitting part 11, and a cylindrical part 32 formed continuously to the reflection part 31 and mounted via an adhesive 4 on the other sealing part 12b. In the sub-reflection mirror 3, a metal member is disposed on an outer peripheral surface of the cylindrical part 32. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a light source device used in devices such as a data projector, a liquid crystal projector, and a DLP (digital light processor) projector. In particular, the present invention relates to a light source device including a discharge lamp in which 0.15 mg / mm ³ or more of mercury is sealed in a light emitting unit and the mercury vapor pressure is 110 atm or more.

In recent years, liquid crystal projectors and DLP projectors using digital light processing technology are becoming popular. In such an apparatus, for example, a light source apparatus configured by combining a light source composed of a discharge lamp and a concave reflecting mirror is used.
FIG. 4 is a cross-sectional view illustrating a configuration of the light source device disclosed in Japanese Patent Laid-Open No. 2005-309372.
The light source device is configured such that one sealing portion 12 a of the discharge lamp 1 is incorporated in the concave reflecting mirror 2, and is disposed horizontally so that the optical axis of the discharge lamp 1 coincides with the central axis of the concave reflecting mirror 2. Has been. The sub-reflecting mirror 3 is attached to the other sealing portion 12 b of the discharge lamp 1 so that the reflecting portion 31 is located in the vicinity of the outer peripheral surface of the light emitting portion 11 of the discharge lamp 1. The sub-reflecting mirror 3 is formed with a cylindrical portion 33 extending in parallel with the sealing portion 12b following the reflecting portion 31 disposed so as to face the concave reflecting mirror 2, and is sealed with the cylindrical portion 33. The adhesive 4 is injected and fixed in the gap between the portion 12b.

  Without the sub-reflecting mirror 3, the light emitted from the light emitting portion 11 of the discharge lamp 1 toward the other sealing portion 12b becomes diffused light that is directly irradiated forward, and the concave reflecting mirror 2 It is not focused on the focal point and cannot be used effectively. However, if the sub-reflecting mirror 3 is provided, the light emitted from the light emitting unit 11 toward the other sealing unit 12 b is reflected by the sub-reflecting mirror 3 and returned to the concave reflecting mirror 2 through the light emitting unit 11. Can do. The light returned from the sub-reflecting mirror 3 to the concave reflecting mirror 2 can be collected and used at the focal point of the concave reflecting mirror 2, and the utilization efficiency of the light emitted from the light emitting unit 11 is improved.

JP 2005-309372 A

However, when the light source device described in Japanese Patent Application Laid-Open No. 2005-309372 is turned on for a long time, the metal foil 14b hermetically sealed to the sealing portion 12b to which the sub-reflecting mirror 3 is attached becomes the sealing portion 12b. It was found that the adhesion with the constituting glass material was weakened, and so-called foil floating phenomenon occurred. As the foil floating progresses, a crack is generated in the sealing portion 12b or the sealing portion 12b is damaged.
The present invention has been made to solve the above problem, and the sub-reflecting mirror is fixed even if it has a sub-reflecting mirror for returning the light emitted from the discharge lamp to the light emitting section. An object of the present invention is to provide a light source device that can suppress the floating of a metal foil provided in a sealing portion and prevent the occurrence of cracks.

In the first invention of the present application, a light emitting part in which electrodes are disposed to face each other, a discharge lamp including a sealing part formed at both ends of the light emitting part and embedded with metal foil, and one sealing part, A concave reflecting mirror attached so as to surround the discharge lamp, a reflecting portion for returning the emitted light from the discharge lamp to the light emitting portion, and an adhesive formed after the reflecting portion are formed on the other sealing portion. In the light source device having a sub-reflecting mirror composed of a cylindrical part attached via a metal member, the sub-reflecting mirror has a metal member disposed on the outer peripheral surface of the cylindrical part.
According to a second invention of the present application, in the first invention, the metal member is a coil.
A third invention of the present application is characterized in that, in the first or second invention, the metal member and an external lead led out from the metal foil are electrically connected.

  According to the light source device according to the first and second inventions of the present application, by attaching a metal member to the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror, around the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror by the photoelectric effect. Photoelectrons are generated and can be charged to a negative charge. Since the trace amount of alkali ions contained in the adhesive is also attracted in the direction of the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror, the alkali metal contained in the adhesive can be made difficult to dissolve into the sealing portion. . The alkali metal contained in the adhesive is prevented from entering the sealing portion, the metal foil is prevented from floating and the occurrence of cracks is prevented.

  According to the light source device according to the third aspect of the present application, the metal member and the metal foil can be set to the same potential by connecting the metal member and the external lead with the conductive wire. Since the members charged at the same potential are arranged on both sides with the adhesive in between, photoelectrons are emitted by the photoelectric effect on the surface of the metal member exposed to light, so that the entry of alkali ions into the sealing portion is further prevented. It can be effectively suppressed.

Sectional drawing which shows the structure of the light source device of 1st Embodiment. Sectional drawing which expands and shows the part to which the subreflector of the light source device of the light source device of FIG. 1 is connected. Sectional drawing which expands and shows the part to which the subreflector of the light source device of 2nd Embodiment is connected. Sectional drawing which shows the structure of the conventional light source device

FIG. 1 is a cross-sectional view illustrating the configuration of the light source device according to the first embodiment.
One sealing portion 12 a of the discharge lamp 1 is configured to be incorporated in the concave reflecting mirror 2, and is disposed horizontally so that the optical axis of the discharge lamp 1 coincides with the central axis of the concave reflecting mirror 2. The sub-reflecting mirror 3 is attached to the other sealing portion 12 b of the discharge lamp 1 so that the reflecting portion 31 is located in the vicinity of the outer peripheral surface of the light emitting portion 11 of the discharge lamp 1.

  The discharge lamp 1 has a substantially spherical light emitting portion 11 made of quartz glass, and electrodes 13 a and 13 b made of tungsten are arranged facing the light emitting portion 11. Further, sealing portions 12a and 12b are formed so as to extend from the end portion of the light emitting portion 11, and conductive metal foils 14a and 14b made of, for example, molybdenum are embedded in the sealing portions 12a and 12b in an airtight manner by a shrink seal. Has been. The pair of electrodes 13a and 13b are electrically connected by welding their base ends to the metal foils 14a and 14b.

A funnel-shaped sub-reflecting mirror 3 made of, for example, quartz glass is attached to the sealing portion 12 b so that the reflecting portion 31 is positioned in the vicinity of the outer peripheral surface of the light emitting portion 11. The sub-reflecting mirror 3 reflects a light by forming a metal vapor deposition film on a semicircular reflecting portion 31 formed so as to correspond to the surface of the light emitting portion 11. For example, the reflective film is formed by alternately laminating a silica (SiO ₂ ) layer and a titania (TiO ₂ ) layer, or a silica (SiO ₂ ) layer and a niobia (Nb ₂ 0 ₅ ) layer. It consists of a dielectric multilayer film of 5 μm to 10 μm and has a function of reflecting visible light having a wavelength of 350 nm to 800 nm.

  Since the light emitted from the light emitting unit 11 toward the sealing unit 12 b is reflected by the sub-reflecting mirror 3, the light returns to the concave reflecting mirror 2 through the reflecting unit 31. The light returned from the sub-reflecting mirror 3 to the concave reflecting mirror 2 can be condensed at the focal point of the concave reflecting mirror 2, and the utilization efficiency of the light emitted from the light emitting unit 11 is improved.

The discharge lamp 1 has a substantially spherical light emitting portion 11 made of quartz glass, and electrodes 13 a and 13 b made of tungsten are arranged facing the light emitting portion 11. Further, sealing portions 12a and 12b are formed so as to extend from the end portion of the light emitting portion 11, and conductive metal foils 14a and 14b made of, for example, molybdenum are embedded in the sealing portions 12a and 12b in an airtight manner by a shrink seal. Has been. The pair of electrodes 13a and 13b are electrically connected by welding their base ends to the metal foils 14a and 14b.

The light emitting unit 11 is filled with mercury, rare gas, and halogen gas.
Mercury is used to obtain a necessary visible light wavelength, for example, radiated light having a wavelength of 360 to 830 nm, and 0.15 mg / mm ³ or more is enclosed. Although the amount of mercury enclosed varies depending on temperature conditions, it is manufactured so that the internal pressure of the light-emitting portion 11 becomes an extremely high vapor pressure of 150 atm or more during lighting. Further, by enclosing a larger amount of mercury, it is possible to manufacture the discharge lamp 1 having a mercury vapor pressure of 200 atm or higher or 300 atm or higher during lighting, and a light source suitable for a projector device can be realized.
The rare gas is used to improve the lighting startability, and for example, argon gas is sealed at about 13 kPa.

As the halogen, iodine, bromine, chlorine, etc. are enclosed in the form of a compound with mercury or other metal, and the amount of halogen enclosed is selected from the range of 1 × 10 ⁻⁶ to 1 × 10 ⁻² μmol / mm ^3. . By enclosing the halogen, a halogen cycle is generated and the life of the discharge lamp 1 can be extended. In addition, the discharge lamp 1 used in the light source device according to the present invention is extremely small and has a high internal pressure. By encapsulating the halogen, there is an effect of preventing the light emitting portion 11 from being blackened and devitrified.

FIG. 2 is an enlarged cross-sectional view showing a portion where the sub-reflecting mirror 3 of the light source device shown in FIG. 1 is connected.
The sub-reflecting mirror 3 is formed with a cylindrical portion 33 extending parallel to the sealing portion 12b following the reflecting portion 31 on which the reflective film is formed, and the sub-reflecting mirror 3 is fixed to the sealing portion 12b by fixing the cylindrical portion 33 to the sealing portion 12b. The reflecting mirror 3 is fixed. The sub-reflecting mirror 3 is filled with the adhesive 4 from the cylindrical portion 33 and fixed to the sealing portion 12b. The adhesive 4 is applied to a position corresponding to a portion covering the metal foil 14b from the vicinity of the rear end of the electrode 13b embedded in the sealing portion 12b.

  Since the sub-reflecting mirror 3 disposed near the light emitting unit 11 becomes hot when the discharge lamp 1 is turned on, the adhesive 4 for fixing the sub-reflecting mirror 3 is made of a silica-based or alumina-based inorganic adhesive having a high heat resistance temperature. Used. The inorganic adhesive contains a small amount of alkali metal such as sodium (Na) or lithium (Li) in order to improve the adhesive strength. Further, since the adhesive 4 for fixing the sub-reflecting mirror 3 is applied in the vicinity of the arc tube 11, the temperature becomes very high compared to the adhesive for fixing the concave reflecting mirror.

  The sodium component and lithium component contained in the adhesive 4 are ionized by the heat radiated when the discharge lamp is turned on to emit electrons to become alkali ions. Since alkali ions are charged to a positive charge, when the electrode 13b performs a cathode operation, it is attracted to the negative charge of the metal foil 14b provided on the sealing portion 12b. Due to such a phenomenon, when the sub-reflecting mirror 3 arranged near the light emitting unit 11 is fixed by the adhesive 4, the adhesive 4 becomes very high temperature, so that a trace amount of metal contained in the adhesive 4 is sealed. It will be in the state which is easy to melt into glassy which constitutes stop part 12b. It is considered that the metal foil 14b was peeled off when the alkali metal contained in the adhesive 4 was dissolved in the sealing portion 12b.

  Therefore, the coil 4 is wound around the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3 so that the alkali metal contained in the adhesive 4 is difficult to dissolve into the sealing portion 12b. Since the reflective film that reflects visible light is formed on the sub-reflecting mirror 3, the ultraviolet light passes through the sub-reflecting mirror 3. The coil 4 wound on the outer surface of the sub-reflecting mirror 3 is exposed to the light emitted from the discharge lamp and transmitted through the sub-reflecting mirror 3 or the light reflected by the concave reflecting mirror. A strong light is irradiated to From the coil 4 irradiated with light, electrons (photoelectrons) are emitted from the surface by the photoelectric effect. By attaching a metal member such as the coil 4 to the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3, the periphery of the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3 can be charged to a negative charge by photoelectrons.

  Since the periphery of the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3 is charged with a negative charge, a trace amount of alkali ions of the metal contained in the adhesive 4 is generated on the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3. Since it is also drawn in the direction, the alkali metal contained in the adhesive 4 can be made difficult to dissolve in the sealing portion 12b as compared with the case where the metal foil 14b is drawn unilaterally only by the negative charge. By preventing the alkali metal contained in the adhesive 4 from entering the sealing portion 12b, the foil floating of the metal foil 14b can be suppressed and the occurrence of cracks can be prevented.

  In the light source device shown in FIG. 1 and FIG. 2, the example in which the coil 4 is wound around the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3 is shown, but the photoelectric effect occurs when the metal surface is irradiated with light. Therefore, the same effect can be obtained even if a metal foil or a net-like metal other than the coil 4 is arranged on the outer peripheral surface of the cylindrical portion 33. Further, the metal member is preferably arranged in an annular shape so as to cover the outer peripheral surface of the cylindrical portion 33, but even if there are intermittent portions where the metal member is not disposed in some places, Since other portions are charged with a negative charge, there is an effect of suppressing the alkali metal contained in the adhesive 4 from entering the sealing portion 12b.

Even when the discharge lamp 1 is turned on by alternating current, a small amount of metal contained in the adhesive 4 is attracted to the metal foil 14b each time the electrode 13b on the side to which the sub-reflecting mirror 3 is connected performs a cathode operation. As a result, the alkali metal is easily dissolved in the sealing portion 12b. Therefore, by arranging a metal member on the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3, an effect of suppressing alkali metal from entering the sealing portion 12b can be obtained.
Further, when the discharge lamp 1 is dc-lit, if the electrode 13b on the side to which the sub-reflecting mirror 3 is connected is used as the cathode, the alkali metal is always attracted to the metal foil 14b and easily melts into the sealing portion 12b. It becomes a state. Naturally, by arranging the metal member on the outer peripheral surface of the cylindrical portion 33, an effect of suppressing the alkali metal from entering the sealing portion 12b can be obtained.

FIG. 3 is an enlarged cross-sectional view showing a portion to which the sub-reflecting mirror 3 of the light source device of the second embodiment is connected.
The light source device according to the second embodiment is the same as the light source device according to the first embodiment, except that the coil 4 wound around the outer peripheral surface of the cylindrical portion 33 of the sub-reflecting mirror 3 and the external lead connected to the metal foil 14b. In this embodiment, a conductive wire 5 for electrically connecting 15b is added.

  The conductive wire 5 is made of a metal wire made of iron chrome having a diameter of 0.3 mm and a length of 15 mm, and is electrically connected by winding both ends around the coil 4 or the external lead 15b. It is drawn so as to extend outward from the external lead 15b and is formed so as not to be in close contact with the sealing portion 12b.

By connecting the coil 4 and the external lead 15b with the conductive wire 5, the coil 4 and the metal foil 14b can be set to the same potential. Since members charged at the same potential are arranged on both sides of the adhesive 4 and photoelectrons are emitted by the photoelectric effect on the surface of the coil 4 exposed to light, the entry of alkali ions into the sealing portion is prevented. It can be suppressed more effectively.
For example, when the electrode 13b operates as a cathode, a negative charge is charged on the metal foil 14b, but the coil 4 is also charged with a negative charge similarly to the metal foil 14b. Furthermore, since photoelectrons are emitted by the photoelectric effect on the surface of the coil 4, more electrons are present in the coil 4, and alkali ions are attracted to suppress entry into the sealing portion.
Further, when the electrode 13b operates as an anode, a positive charge is charged on the metal foil 14b, but the coil 4 is also charged with a positive charge similarly to the metal foil 14b. However, since photoelectrons are emitted by the photoelectric effect on the surface of the coil 4, many electrons exist in the coil 4, attracting alkali ions to suppress entry into the sealing portion.

  In addition, when the coil 4 is conducted to the external lead 15 b, electrons are supplied to the coil 4 through the conductive wire 5. Therefore, even if photoelectrons are emitted from the coil 4, the electrons are not depleted, and photoelectrons can be continuously emitted from the coil 4.

Next, examples will be described. An experiment was conducted to examine the presence or absence of cracks occurring in the sealing portion when the coil was wound around the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror and when there was no coil. The specifications of the discharge vessel, the sub-reflecting mirror, the coil, and the adhesive used as the test object are shown below.
Discharge vessel: material: quartz glass, maximum diameter of light emitting part: φ10.0 mm, sealing part diameter φ5-6 mm
Sub-reflecting mirror: Material: Quartz glass, maximum diameter of reflecting part: φ14 mm, cylindrical part outer diameter φ9 mm, cylindrical part length 6 mm
Coil: Material: Iron-chromium alloy wire, strand diameter φ0.3 mm, winding diameter φ9.6 mm to 10 mm, total length 6 mm
Adhesive: Material: Silica / alumina based inorganic adhesive, alkali metal content 10000 ppm

  Prepare 10 discharge lamps each with a coil with no conductive wire connected to the outer peripheral surface of the cylindrical part of the sub-reflecting mirror, and 10 discharge lamps with no coil wound around them, and supply alternating current power for continuous lighting An experiment was conducted. Each time the lighting time was 100 hours, 200 hours, 500 hours, 1000 hours, 1500 hours, and 2000 hours, the presence or absence of cracks in the sealing portion was visually confirmed. The experimental results are listed in the table below.

In a discharge lamp in which a coil is wound around the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror, no cracks were generated even after lighting for 2000 hours. In the discharge lamp in which the coil is not wound around the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror, the probability that a crack occurs in the sealing portion increases as the lighting time increases.
From the above results, it was confirmed that in the discharge lamp in which the coil is wound around the outer peripheral surface of the cylindrical portion of the sub-reflecting mirror, no crack is generated in the sealing portion.

DESCRIPTION OF SYMBOLS 1 Discharge lamp 2 Concave reflecting mirror 3 Subreflecting mirror 4 Coil 5 Conductive wire 11 Light emission part 12a, b Sealing part 13a, b Electrode 14a, b Metal foil 15b External lead 31 Reflection part 32 Cylindrical part

Claims (3)

A discharge lamp comprising a light emitting part in which electrodes are arranged opposite to each other, and a sealing part formed at both ends of the light emitting part and embedded with metal foil;
A concave reflecting mirror attached to one sealing portion so as to surround the discharge lamp;
A sub-reflecting mirror comprising a reflecting portion for returning the emitted light from the discharge lamp to the light emitting portion, and a cylindrical portion that is formed following the reflecting portion and attached via an adhesive to the other sealing portion; In the light source device having
In the light source device, the sub-reflecting mirror has a metal member disposed on an outer peripheral surface of a cylindrical portion. The light source device according to claim 1, wherein the metal member is a coil. The light source device according to claim 1, wherein the metal member is electrically connected to an external lead led out from the metal foil.

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