JP2010262895A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a short arc type discharge lamp using an auxiliary lamp 5 even if it has a concave reflecting mirror 2 surrounding a short arc type discharge lamp 1 and a sub reflecting mirror 3 for returning radiated light to a light emitting part 11. To provide a light source device capable of reliably lighting 1.
SOLUTION: A short arc type discharge lamp 1 in which sealing portions 12a and 12b are formed at both ends of a light emitting portion 11, and a neck portion 21 is attached to one sealing portion 12a. In the light source device having the concave reflecting mirror 2 that surrounds and the sub-reflecting mirror 3 that is attached to the other sealing portion 12b and returns the emitted light from the short arc type discharge lamp 1 to the light emitting portion 11.
An auxiliary lamp 5 that emits ultraviolet rays is provided at a position where radiant light is taken into the sub-reflecting mirror 3.

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 short arc type discharge lamp in which 0.15 mg / mm ³ or more of mercury is sealed in a light emitting unit and a 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. Since such a device is widely used in general, the safety of handling is required, and a low start type in which a voltage applied at the start is reduced is adopted. However, if the starting voltage is lowered, the voltage may not be lit because the voltage required for dielectric breakdown is not reached.
Therefore, Japanese Patent Application Laid-Open No. 2004-139955 radiates ultraviolet rays from an auxiliary lamp at the time of starting, promotes photoelectron emission by the photoelectric effect of the substance in the discharge vessel and ionization of the discharge medium, and requires a dielectric breakdown voltage required at the time of starting. Is lowered. By reducing the voltage required for dielectric breakdown, the low start-up type can be lit reliably.

  In addition, various attempts have been made to increase the utilization efficiency of light emitted from the light source device. In Japanese Patent Application Laid-Open No. 2005-309372, a reflecting portion is provided in a short arc type in a sealing portion of a short arc type discharge lamp. There has been proposed a light source device to which a sub-reflecting mirror is attached so as to be positioned in the vicinity of the outer peripheral surface of the light emitting portion of the discharge lamp. The light emitted directly forward from the concave reflecting mirror could not be used effectively because it was not collected at the focal point of the concave reflecting mirror, but by providing a secondary reflecting mirror, it was reflected by the secondary reflecting mirror to be concave. It can be returned to the reflector. The light returned from the sub-reflecting mirror to the concave reflecting mirror can be collected and used at the focal point of the concave reflecting mirror, so that the utilization efficiency of the light emitted from the light emitting unit is improved.

JP 2004-139955 A JP 2005-309372 A

However, when the light source device described in Japanese Patent Application Laid-Open No. 2005-309372 is a low start type using an auxiliary lamp, there is a problem in that the light source device may not light up.
The present invention has been made to solve the above problem, and includes a concave reflecting mirror surrounding the short arc type discharge lamp and a sub-reflecting mirror for returning the emitted light to the light emitting portion. An object of the present invention is to provide a light source device capable of reliably lighting a short arc type discharge lamp using an auxiliary lamp.

The first invention of the present application is a short arc type discharge lamp formed, a neck part attached to one sealing part, a concave reflecting mirror surrounding the short arc type discharge lamp, and a second sealing part. And a sub-reflecting mirror for returning the radiated light from the short arc discharge lamp to the light emitting unit, an auxiliary lamp for radiating ultraviolet rays is provided at a position where the radiated light is taken into the sub-reflecting mirror. It is characterized by being.
According to a second invention of the present application, in the first invention, a concave portion is formed in a neck portion of the concave reflecting mirror, and an auxiliary lamp is disposed between the one sealing portion and the concave portion. .
According to a third invention of the present application, in the second invention, the first sealing portion is inserted, the base of the concave reflecting mirror is mounted, and the auxiliary lamp is attached to the base. Features.
A fourth invention of the present application is characterized in that, in the first invention, a reflection film containing a tantalum compound or a hafnium compound is formed on the sub-reflecting mirror.
A fifth invention of the present application is characterized in that, in the first invention, the auxiliary lamp has an ultraviolet reflecting film formed on a part of the surface of the container.

  According to the light source device of the first invention of the present application, an auxiliary lamp that radiates ultraviolet rays is disposed at a position where radiated light is taken into the sub-reflecting mirror, so that the auxiliary reflecting mirror covers the light emitting part even if the sub-reflecting mirror covers the light emitting unit. Light from the lamp is reflected by the sub-reflecting mirror and is easily taken into the light emitting unit. The light emitted from the auxiliary lamp toward the light emitting part is added to the light reflected by the reflecting part of the sub-reflecting mirror, so that the light for starting assistance is irradiated, and the light is emitted inside the light emitting part. The amount of light that can be increased. When the material in the discharge vessel is irradiated with light, the photoelectric effect promotes photoemission and ionization of the discharge medium, lowers the breakdown voltage required at the start, and improves the startability of the short arc type discharge lamp. .

  According to the light source device according to the second invention of the present application, the concave portion is formed in the neck portion of the concave reflecting mirror, a gap is formed between the one sealing portion and the neck portion, and the auxiliary lamp is disposed in the gap. . Since the auxiliary lamp is not arranged on the opening side of the concave reflecting mirror, the auxiliary lamp is provided with an auxiliary lamp so that the light radiated from the short arc type discharge lamp does not become an obstacle in the optical path reflecting forward. It can be placed at a position where the emitted light is captured.

  According to the light source device of the third invention of the present application, the auxiliary lamp is arranged on the base, and the sealing part, the concave reflecting mirror, and the auxiliary lamp are bonded to each other while being arranged at the position where the radiated light is taken into the sub-reflecting mirror. Can be easily fixed with an agent.

  According to the light source device of the fourth invention of the present application, the reflective film containing the tantalum compound or the hafnium compound is formed on the sub-reflecting mirror, so that the reflecting portion of the sub-reflecting mirror also reflects ultraviolet rays. More ultraviolet rays can be taken into the light emitting part, and the startability of the short arc type discharge lamp can be further improved.

  According to the light source device of the fifth aspect of the present application, in addition to the light traveling from the auxiliary lamp to the light emitting unit or the sub-reflecting mirror, the light reflected by the ultraviolet reflecting film can also be used for starting assistance, and is reflected from the auxiliary lamp. The amount of light emitted toward the part increases. In the photoelectric effect, when the light intensity is increased, the number of photoelectrons emitted is increased, so that the voltage required for dielectric breakdown can be reduced. Therefore, the startability of the short arc type discharge lamp can be further improved.

Sectional drawing which shows the structure of a light source device View of the light source device seen from the neck of the concave reflector A perspective view for explaining an auxiliary lamp Sectional drawing which shows the structure of a light source device

FIG. 1 is a cross-sectional view showing the configuration of the light source device.
One sealing portion 12a of the short arc type discharge lamp 1 which is the main light source of the light source device is incorporated in the concave reflecting mirror 2 so that the optical axis of the short arc type discharge lamp 1 coincides with the central axis of the concave reflecting mirror 2. Are arranged horizontally. A part of the neck portion 21 is removed to form a concave portion 22, and a space-free portion where no structure is arranged around the sealing portion 12 a is formed. An auxiliary lamp 5 serving as an auxiliary light source at the time of start-up is disposed in a gap formed by providing the concave portion 22 in the neck portion 21.

  In a state where the auxiliary lamp 5 is disposed in the concave portion 22, the adhesive 41 is filled between the sealing portion 12 a and the neck portion 21, and the neck portion 21, the sealing portion 12 a, and the auxiliary lamp 5 of the concave reflecting mirror 2 are connected. It is stuck. The adhesive 41 is filled in the gap of the base 4 at a location where the auxiliary lamp 5 is not disposed so that the light emitted from the auxiliary lamp 5 is not blocked by the adhesive 41.

The other sealing portion 12b of the short arc type discharge lamp 1 has a funnel shape made of, for example, quartz glass so that the reflecting portion 31 is located in the vicinity of the outer peripheral surface of the light emitting portion 11 of the short arc type discharge lamp 1. A sub-reflecting mirror 3 is attached. In the sub-reflecting mirror 3, a reflective film is formed on a semicircular reflecting portion 31 formed so as to correspond to the surface of the light emitting portion 11 to reflect light. 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 part 11 toward the sealing part 12 b is reflected by the sub-reflecting mirror 3, it returns to the concave reflecting mirror 2 via the reflecting part 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 short arc type 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 opposite to 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 a conductive metal foil 14 made of, for example, molybdenum is embedded in the sealing portions 12a and 12b in an airtight manner by a shrink seal. Yes. The pair of electrodes 13a and 13b are electrically connected by welding their base ends to the metal foil 14.

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. In addition, it is possible to manufacture a short arc type discharge lamp 1 in which mercury vapor pressure during lighting becomes 200 atm or more or 300 atm or more by enclosing more mercury, and a light source suitable for a projector device can be realized. it can.
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 short arc type discharge lamp 1 can be extended. Further, in the case of an extremely small and high internal pressure such as the short arc type discharge lamp 1 used in the light source device of the present invention, the effect of preventing the blackening and devitrification of the light emitting portion 11 is obtained by enclosing halogen. is there.

FIG. 2 shows a view of the light source device viewed from the neck portion 21 of the concave reflecting mirror 2.
The sealing part 12a protrudes in the center, and the concave reflecting mirror 2 is fixed by an adhesive so as to surround the sealing part 12a. A part of the end portion of the neck portion 21 of the concave reflecting mirror 2 is removed in the shape of a crescent moon to form a concave portion 22. The auxiliary lamp 5 is disposed in a semicircular gap that is vacated by forming the recess 22. Since the auxiliary lamp 5 is cylindrical, most of the central container 51 is disposed in the gap between the sealing portion 12 a and the neck portion 21, but the external electrodes 52 at both ends are disposed at positions hidden by the neck portion 21.

  A square with rounded corners indicates the opening of the concave reflecting mirror 2, and a circular dotted line between the sealing portion 12 a and the base 4 indicates the opening 33 of the sub-reflecting mirror 3. The auxiliary lamp 5 is arranged such that at least a part of the portion of the container 51 where the external electrode 52 is not formed is included in the range of the tube axis of the short arc type discharge lamp 1 to the opening 33 of the sub-reflecting mirror 3. Yes. With this arrangement, the light emitted from the auxiliary lamp 5 is taken into the sub-reflecting mirror 3, reflected by the reflecting portion 31, and directed toward the light emitting portion 11.

FIG. 3 is a perspective view for explaining the auxiliary lamp 5.
The container 51 of the auxiliary lamp 5 has a circular tube shape whose both ends are sealed, and is formed so that at least a part thereof is transparent to ultraviolet rays having a short wavelength, for example, quartz glass. In the container 51, one or more gases such as nitrogen or helium are sealed as a discharge medium in addition to a rare gas such as argon, xenon, or neon.

  At both ends of the container 51, a pair of external electrodes 52 is formed by winding a wire in a coil shape so as to be in close contact with the outer surface in a length of 0.5 to 5.0 mm in the tube axis direction. . The material of the external electrode 52 is made of a material excellent in oxidation resistance at high temperature and thermal shock, and examples thereof include stainless steel and cantal (iron-chromium alloy). When a voltage is applied between the pair of external electrodes 52, dielectric barrier discharge is induced in the space by electrostatic coupling, and auxiliary discharge is started. The external electrode 52 having a larger area covering the outer periphery of the container 51 increases the capacitance between the external electrodes 52 and facilitates the start of discharge, so that the insulation distance of the external electrode 52 can be ensured. It is good to provide a wide range.

As an example of the configuration of the auxiliary lamp 5, the container 51 is formed of a thin glass tube having a total length of 15 mm, an outer diameter of 3 mm, and a wall thickness of 0.8 mm, for example. Of 1 × 10 ³ Pa is enclosed. External electrodes 52 are formed at both ends of the container 51, and the length in the tube axis direction of one external electrode 52 is 15 mm, and a stainless steel wire of φ0.3 mm is formed in a coil shape so as to adhere to the outer surface of the container 51. Wrapped and configured.

  Such an auxiliary lamp 5 is disposed in the concave portion 22 of the neck portion 21 of the concave reflecting mirror 2 as shown in FIG. Since the sub-reflecting mirror 3 is formed so as to return the light emitted from the light emitting unit 11 to the concave reflecting mirror 2, the light emitted from the concave reflecting mirror 2 side is reflected by the reflecting unit 31 of the sub-reflecting mirror 3. Reflected toward the light emitting unit 11. If the auxiliary lamp 5 is within a visible range as viewed from the sub-reflecting mirror 3, the emitted light from the auxiliary lamp 5 is taken into the sub-reflecting mirror 3.

  Since the sub-reflecting mirror 3 having a reflecting film formed on the reflecting portion 31 is attached to the outer peripheral surface of the light emitting portion 11 from the sealing portion 12b, the light is transmitted from the opening side of the concave reflecting mirror 2 to the inside of the light emitting portion 11. Cannot be imported. However, by arranging the auxiliary lamp 5 at a position where the radiated light is taken into the sub-reflecting mirror 3, the light from the auxiliary lamp 5 is reflected by the sub-reflecting mirror 3 even when the light emitting unit 11 is covered with the sub-reflecting mirror 3. Thus, the light emitting unit 11 can be taken into the interior.

  Although the light radiated from the auxiliary lamp 5 does not have special directivity, a part of the light travels along the tube axis of the short arc type discharge lamp 1, and the reflecting portion of the sub-reflecting mirror 3. The light is reflected by 31 and is taken into the light emitting unit 11. The light radiated from the auxiliary lamp 5 toward the light emitting unit 11 is added with the light reflected by the reflecting unit 31 of the sub-reflecting mirror 3 to irradiate, and the amount of light irradiated inside the light emitting unit 11 is increased. be able to. When the substance in the discharge vessel is irradiated with light, the photoelectric effect promotes photoelectron emission and ionization of the discharge medium, lowers the breakdown voltage required at the start, and improves the startability of the short arc discharge lamp 1 To do.

  Since the auxiliary lamp 5 has such a function, it can function sufficiently if it is lit only when the short arc type discharge lamp 1 is started. Therefore, the auxiliary lamp 5 can be always lit when the short arc type discharge lamp 1 is operated, but can be operated so as to be lit only when the short arc type discharge lamp 1 is started.

Whether or not the radiated light of the auxiliary lamp 5 is taken into the sub-reflecting mirror 3 can be confirmed as follows.
As a simple method, there is a method of checking with the naked eye. For example, the sub-reflecting mirror 3 is removed, and a jig made of a plate-like member having a hole in the size range of the sub-reflecting mirror 3 is inserted from the opening of the concave reflecting mirror 2. If the auxiliary lamp 5 can be confirmed from the hole of the plate-like member, the emitted light from the auxiliary lamp 5 is taken into the sub-reflecting mirror 3.
In order to confirm accurately, there is a method of ray tracing by simulation. The dimensions of each member of the light source device are measured, and the actual light source device is reproduced on the simulation. Using this, ray tracing is performed using simulation software such as TracePro. From this ray tracing diagram, it is possible to confirm whether or not the rays of the emitted light from the auxiliary lamp 5 are taken into the sub-reflecting mirror 3.

The photoelectric effect that improves the startability of the short arc type discharge lamp 1 is particularly desirable to use light having a short wavelength such as ultraviolet rays. Therefore, the reflection part 21 of the sub-reflecting mirror 3 also reflects ultraviolet rays having a wavelength of 350 nm or less. The effect can be enhanced by coating with a film. Whether to reflect ultraviolet rays depends on the attribute of the metal to be coated, but can be realized, for example, by alternately laminating silica (SiO ₂ ) layers and tantalum compound (Ta ₂ O ₅ ) layers. Further, a heat-resistant multilayer film using a hafnium compound (HfO ₂ ) instead of the tantalum compound (Ta ₂ O ₅ ) can be used. Further, instead of a heat-resistant multilayer film, a single metal vapor deposition film of aluminum (Al) or gold (Au), which are single metals, can be used. Ultraviolet rays can also be reflected by the reflecting portion 21 of the sub-reflecting mirror 3, so that more ultraviolet rays can be taken into the light emitting portion 11, and the startability of the short arc type discharge lamp 1 can be further improved.

  Since the sub-reflecting mirror 3 is made of quartz glass having a large heat capacity, the sub-reflecting mirror 3 functions as a heat insulating member that warms the sealing portion 13b side, and also has a function of suppressing a temperature drop of the electrode 13b disposed on the sealing portion 13b side. . For this reason, when the short arc type discharge lamp 1 is turned off from the lighting state, the mercury evaporated during the lighting is attached to the electrode 13a on the sealing portion 13a side where the temperature drop is relatively fast. As for the photoelectric effect, electrons are more likely to jump out and the effect is more easily obtained when the surface of the solid metal is irradiated with light than with the liquid metal. When the reflected light from the auxiliary lamp 5 is reflected by the reflecting portion 31 of the sub-reflecting mirror 3, the light emitted from the auxiliary lamp 5 is applied to the electrode 13b on the sealing portion 12b side where mercury is not attached. This makes it easier for electrons to fly from the metal surface and enhances the photoelectric effect.

  Moreover, although the case where the auxiliary lamp 5 is fixed to the inner side of the neck portion 21 of the concave reflecting mirror 2 has been described in the above description, the present invention is not limited to this. The light emitted from the auxiliary lamp 5 may be disposed at a position where the sub-reflector 3 takes in the emitted light. The lead wire of the external electrode 52 of the auxiliary lamp 5 is fastened with a wire, and the concave reflection on the opening side from the neck 21 is performed. It can also be arranged inside the mirror 2.

FIG. 4 is a cross-sectional view showing another embodiment of the light source device, and shows a case where an ultraviolet reflecting film 53 is formed on the container 51 of the auxiliary lamp 5.
A cap-shaped base 4 made of ceramics and centered in a circular shape is attached to the neck portion 21 of the concave reflecting mirror 2. One sealing portion 12a of the short arc type discharge lamp 1 is inserted through the central hole of the base 4, and the concave reflecting mirror 2 is incorporated and fixed inside the base. By arranging the auxiliary lamp 5 on the base 4, the sealing portion 12 a, the concave reflecting mirror 2, and the auxiliary lamp 5 can be easily fixed with the adhesive 41 and securely so that the auxiliary lamp 5 does not fall. it can.

  The auxiliary lamp 5 is arranged so that the tube axis of the container 51 is substantially perpendicular to the tube axis of the short arc type discharge lamp 1, and when a voltage is applied to the external electrode, the auxiliary lamp 5 is directed from the container 51 in all directions. Ultraviolet light is emitted. Since the ceramics constituting the base 4 and the adhesive filled in the periphery do not transmit light, the light emitted from the container 51 toward the rear from the auxiliary lamp 5 cannot be used for starting assistance. In order to use the light that is not effectively used for starting assistance but discarded, an ultraviolet reflecting film 53 is provided on the surface of the container 51.

Since the container 51 has a cylindrical shape, a linear ultraviolet reflective film 53 extending in the axial direction is formed only on the surface of the portion facing the base 4, and the container 51 is generated inside the container 51 toward the base 4. The emitted light can be reflected toward the front side where the sub-reflecting mirror 3 is arranged. The ultraviolet reflecting film 53 is formed by, for example, alternately laminating silica (SiO ₂ ) layers and tantalum compound (Ta ₂ O ₅ ) layers.

  The base 4 made of ceramics is impermeable, and the light emitted from the container 51 toward the base 4 cannot be used for starting assistance, but the surface of the part of the container 51 facing the base 4, that is, a concave reflecting mirror. By forming the ultraviolet reflection film 53 on the surface of the base end side of the light 2, the light emitted toward the base 4 and discarded can be reflected on the ultraviolet reflection film 53 and used for starting assistance. In addition to the light directed to the light emitting section 11 or the reflecting section 31 of the sub-reflecting mirror 3, the light reflected by the ultraviolet reflecting film 53 can also be used for starting assistance, and is irradiated from the auxiliary lamp 5 toward the reflecting section 11. The amount of light increases. In the photoelectric effect, when the intensity of light is increased, the number of photoelectrons jumped out increases, so that the voltage required for dielectric breakdown can be further reduced. Therefore, the startability of the short arc type discharge lamp 1 can be further improved.

Although not shown in the figure, even when two or more auxiliary lamps 5 are arranged in the light source device, the amount of light irradiated toward the reflecting portion 11 is increased, the photoelectric effect is increased, and the voltage required for dielectric breakdown is decreased. be able to.

DESCRIPTION OF SYMBOLS 1 Short arc type discharge lamp 2 Concave reflecting mirror 3 Subreflecting mirror 4 Base 5 Auxiliary lamp 11 Light emission part 12a, b Sealing part 13a, b Electrode 31 Reflection part 32 Cylindrical part 33 Opening 51 Container 52 External electrode 53 Ultraviolet reflective film

Claims (5)

A short arc type discharge lamp in which sealing portions are formed at both ends of the light emitting portion;
A concave reflection mirror having a neck attached to one sealing portion and surrounding the short arc discharge lamp;
In a light source device having a sub-reflecting mirror attached to the other sealing portion and returning the emitted light from the short arc type discharge lamp to the light emitting portion,
An auxiliary lamp that radiates ultraviolet rays is provided at a position where radiant light is taken into the sub-reflecting mirror. 2. The light source device according to claim 1, wherein a concave portion is formed in a neck portion of the concave reflecting mirror, and an auxiliary lamp is disposed between one sealing portion of the discharge lamp and the concave portion. The light source device according to claim 2, further comprising a base through which the one sealing portion is inserted and a neck portion of the concave reflecting mirror is mounted, and the auxiliary lamp is attached to the base. The light source device according to claim 1, wherein a reflection film containing a tantalum compound or a hafnium compound is formed on the sub-reflecting mirror. The light source device according to claim 1, wherein the auxiliary lamp has an ultraviolet reflecting film formed on a part of a surface of the container.

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