JP2842077B2 - Projection light source device, projection light source operating device, and liquid crystal projector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light projection light source device, a light projection light source operating device, and a liquid crystal projector in which light emitted from a metal halide lamp is reflected by a reflector and projected.

[0002]

^2. Description of the Related Art In a metal halide lamp used at a high tube wall load of 40 W / cm ² or more, the tube wall temperature at the time of lighting is increased to a level near the endurable limit of quartz glass which is a material of an airtight container, and the tube wall is lost. Transparency occurs remarkably. This devitrification portion is crystal of a type of SiO ₂ that cristobalite formed on the inner surface of the quartz, a reticulated SiO ₂ and elemental composition ratio of normal quartz glass identical, Si and O
The arrangement of ₂ is changed from an amorphous to a regular arrangement of crystals.

[0003] When such devitrification occurs, the amount of light from the lamp to the reflecting surface of the reflector is greatly reduced, so that the available effective light amount is reduced. When such a lamp is used in a liquid crystal projector, there is a disadvantage that the illuminance on the screen is extremely reduced.

FIG. 5 is a partially cutaway perspective view showing a conventional light emitting light source device disclosed in Japanese Patent Application Laid-Open No. 4-32154. The light emitting tube 71 is a reflector 7 having a parabolic surface.
2 is provided with a blower hole 74 in the vicinity of a base 73 supporting the end of the arc tube 71. In order to prevent devitrification of the arc tube 71, a blower hole 74 near the base 73 is provided. The luminous tube 71 is cooled by blowing air.

In the case of a metal halide lamp having a low tube wall load, the light output does not decrease over time due to devitrification. Therefore, there is no need to cool the arc tube as disclosed in Japanese Patent Application Laid-Open No. 4-32154. Also, since the tube wall load is low, a desired screen illuminance cannot be obtained, and the light source is unsuitable for a liquid crystal projector.

[0006]

FIG. 5 shows that:
Since the arc tube 71 is blown and cooled from the base portion 73 side, if the devitrification of the arc tube portion on the reflection surface side is reduced, the amount of light traveling from the lamp to the reflection surface of the retarder may not be significantly reduced. It is necessary to provide the ventilation hole 74 in the vicinity of the portion 73, and the configuration becomes extremely complicated.

[0007] US Pat. No. 5,107,165 discloses that
There is a description of an automobile headlamp having a configuration in which a cathode of a metal halide lamp housed in a reflecting mirror is arranged on a light emitting opening side. Although the specific tube wall load of this is unknown, the lamps used for automobile headlamps are at most 2
Since the tube wall load of about 5 W / cm ² is small, there is almost no problem of devitrification.

According to the present invention, there is provided a light projecting light source device which suppresses a decrease in the amount of reflected light due to devitrification, suppresses a decrease in illuminance on a screen over time with a simple structure, and obtains a high light output.
An object of the present invention is to provide a light emitting light source operating device and a liquid crystal projector.

[0009]

Means for Solving the Problems] claim 1, major portions of quartz glass of the airtight container, a metal halide sealed in the pair of electrodes and hermetic containers FuSo inside both ends of the vessel, mercury And noble gas, tube wall load is 40W
A metal halide lamp which is DC-lit to be at least / cm ² ; a reflector which has a light-transmitting opening and which is housed such that the electrode operating as a cathode of the metal halide lamp is positioned on the light-transmitting opening side; A light projection light source device comprising:

In the present invention, the hermetic container is a container constituting the arc tube. In the present invention, the tube wall load refers to a value obtained by dividing the input power W by the inner surface area Scm ² of the airtight container.

[0011] Claim 2 is, quartz glass of the airtight container, one end FuSo cathodic of the vessel, a metal halide sealed in the FuSo anodes and hermetic container at the other end, mercury and a rare gas A metal halide lamp configured to be operated so as to have a tube wall load of 40 W / cm ² or more; a bowl shape having a light-transmitting opening, and an anode of the metal halide lamp and a bottom side of the bowl shape; And a reflector that houses the metal halide lamp with the cathode positioned on the light-transmitting opening side.

[0012] Claim 3, quartz glass of the airtight container, one end FuSo cathodic of the vessel, a metal halide sealed in the FuSo anodes and hermetic container at the other end, mercury and a rare gas A metal halide lamp having a light suppressing means on the surface of the airtight container on the side of the light-transmitting opening; and a bowl having a light-transmitting opening, wherein the anode of the metal halide lamp is provided on the bottom side of the bowl and the cathode is provided on the bottom. And a reflector, which is located on the side of the light-transmitting opening and accommodates the metal halide lamp, respectively.

In the present invention, the light suppressing portion includes a diffusion surface formed by frost processing or the like for reducing light transmittance. According to a fourth aspect of the present invention, there is provided the light emitting light source device according to the first or second aspect; and a DC power supply for stably forming a discharge between the electrodes of the metal halide lamp of the light emitting light source device. A light projecting light source operating device, characterized in that:

In the present invention, DC lighting or DC of a DC power supply includes rectified AC, pulse lighting, and the like. Claim 5 is a projection light source operating device according to claim 4, an optical system for projecting light from the projection light source device onto a screen, and a liquid crystal panel disposed in the optical system; A liquid crystal projector comprising: a light emitting light source operating device; an optical system; and a housing for housing the liquid crystal panel.

[0015] In the present invention, the optical system is an example when the projection lens. According to a sixth aspect of the present invention, there is provided the liquid crystal projector according to the fifth aspect, wherein the reflector is provided so that the light transmitting opening faces downward.

[0016]

According to the first aspect, when the tube wall load is set to 40 W / cm ² or more, a high light output is obtained, but the occurrence of devitrification of the airtight container becomes remarkable. However, since the light emitting metal ions are attracted to the cathode by the DC lighting, devitrification is suppressed for a long time on the tube wall and the anode side at the center of the arc, and the transparent state is maintained. In the lamp of the first aspect, since the cathode is disposed on the light-transmitting opening side of the reflector, the amount of light directly projected from the lamp to the front of the reflector may be reduced due to devitrification. The decrease in the amount of light toward is suppressed. Light that is directly output from the lamp to the light-transmitting aperture is light that is not controlled by the reflector, and is light that does not originally contribute as light. That is, the amount of light directly projected from the lamp to the front of the reflector is light that does not substantially contribute even if reduced due to devitrification, and therefore does not substantially decrease the amount of light. Therefore, the amount of reflected light is unlikely to decrease with time.

The second aspect has the same function as the first aspect. According to the third aspect, even if devitrification occurs on the cathode side of the hermetic container, the light suppressing means is provided in the portion of the hermetic container corresponding to the devitrified portion. For example, since the light from the light source does not substantially irradiate the light projecting surface such as a screen, it is possible to suppress a temporal change in the amount of irradiation light due to devitrification on the cathode side.

[0018] Claim 4 has the effect of either claim 1 or 2 . Claim 5 has the function of claim 4 .
Claim 6 has the function of claim 5, and furthermore, since the cathode is disposed vertically below the anode,
In addition to the ions of the luminescent metal being attracted to the cathode, the luminescent metal also gathers near the lower cathode by the action of gravity, thereby suppressing devitrification at the center and upper portions of the lamp.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in FIGS. FIG. 1 is a partial cross-sectional side view showing a horizontal lighting state of a light emitting light source operating device. FIG.
, 20 is an airtight container made of quartz glass,
The light-emitting portion of the airtight container 20 has a substantially spheroidal shape made of 1.4 mm thick quartz glass. The light emitting portion is formed so that the major axis is about 15 mm and the minor axis is about 10 mm, and as a result, the inner surface area is approximately 4.7 cm ² and the inner volume is approximately 0.9 cc.

Electrodes 21a and 21b are sealed at both ends of the airtight container 20, respectively. These electrodes 21a,
21b is designed to be DC-lit, so that one electrode 21a is a cathode and the other electrode 21b is an anode. However, in the case of the present embodiment, these cathodes 21
a and the anode 21b both have the same structure, and each is made of a tungsten-thorium alloy containing thorium, and is 10 mm long and 0.7 mm thick.
The electrode coil 212 is formed by winding a tungsten wire having a wire diameter of 0.5 mm tightly three times. The distance L between the cathode 21a and the anode 21b is 6
mm.

The pair of electrodes 21a, 21b are connected to metal foil conductors 23, 23 sealed in the sealing portions 22, 22, respectively. The metal foil conductors 23, 23 are Mo foils and have a width of 3 mm and a thickness of 30 μm. One of the metal foil conductors 23 connected to the anode 21b is electrically connected to a base 24 attached to an end via an external lead wire (not shown), and is connected to the cathode 21a. The other metal foil conductor 23 is connected to an external lead wire 25.
The external lead wire 25 is made of a 0.8 mm-diameter Mo metal rod.

Such an airtight container 20 contains, for example, 22 mg of mercury and a rare earth metal such as Dy, Nd, Tl, In, Sn, Cs as a luminescent metal.
2.0 mg of iodide and bromide, etc., and 40 KPa of argon gas as a rare gas are further included to constitute the short arc metal halide lamp 1.

This lamp 1 is mounted on a reflector 2. The reflector 2 is made of glass or metal, and TiO ₂ —Si having excellent reflection characteristics is formed on the inner surface of the rotating curved surface.
It has a reflective surface 31 made of a deposited film of O ₂ or the like. The front projection part of the reflector 2, for example, the opening has an opening diameter of 9
The support tube 32 is formed at the top of the back. The base 24 of the lamp 1 is fixed to the support tube 32 with an adhesive 33 such as insulating cement. Thereby, the lamp axis O of the lamp 1 is
₁ −O ₁ is the central axis of the reflector 2, that is, the optical axis O ₂ −
The lamp 1 is mounted on the reflector 2 so as to substantially coincide with O ₂ .

In this case, the lamp 1 is supported by the reflector 2 with the cathode 21a positioned on the front projection side of the reflector 2 and the anode 21b positioned on the support cylinder 32. The reflector 2 is formed with an introduction hole 34, through which the external lead wire 25 of the lamp 1 is guided to the rear side.

The light projecting light source device 60 is constituted by the reflector 2 and the short arc metal halide lamp 1 fixed to the reflector 2 as described above.
And the external lead wire 25 are connected to a DC power supply 50 to constitute a light emitting light source operating device. The DC power supply 50 applies a voltage to the lamp 1 such that the no-load voltage becomes approximately 280 V, for example. By applying such a voltage, the lamp is turned on by direct current, the lamp current becomes 2.7 A, the lamp voltage is 92 V, and the lamp power is 247 W.

The operation of the light projecting light source device 60 having the above configuration will be described. In the light projecting light source device 60, as shown in FIG. 1, the reflector 2 is used with its optical axis O ₂ -O ₂ oriented substantially horizontally, and the short arc metal halide lamp 1 is horizontally lit.

Since the short arc metal halide lamp 1 is connected to the DC power supply 50 and is lit by DC, the metal ions in the hermetic container 20 are strongly affected by the electric field in the hermetic container created by both electrodes and the cathode is It is drawn to the 21a side. For this reason, the ions of the rare earth metal continue to be electrically attracted to the negative electrode 21a, and as a result, the metal ions move away from the quartz glass in the central portion of the hermetic container 20 where the temperature is high or the quartz glass on the side of the anode 21b. The occurrence of devitrification at the center and on the anode 21b side is suppressed. That is, if devitrification occurs, the airtight container 2
0 is generated on the cathode 21a side.

As a result, the amount of light directly radiated forward from the lamp 1 slightly decreases due to the devitrification, but the decrease in the amount of light traveling from the central portion or the transparent region on the side of the anode 21b toward the reflection surface 31 does not decrease. Be deterred. Therefore, a decrease in the amount of light reflected by the reflecting surface 31 is suppressed, and a decrease in the amount of light projected from the light emitting light source device 60 can be suppressed. Therefore, when the light from the light projecting light source device 60 is projected on, for example, a screen or the like, it is possible to suppress a decrease in illuminance of the screen.

FIG. 2 is a life characteristic diagram showing the degree of decrease in illuminance on the screen. In FIG. 2, the vertical axis indicates the illuminance reduction rate on the screen, and the horizontal axis indicates the lighting time. In FIG. 2, in the case of the present invention shown by a solid line, the decrease in illuminance on the screen is small and the life characteristics are improved as compared with the conventional AC lighting shown by the broken line.

In FIG. 1, if a light suppressing portion 40, for example, a diffusion surface such as a frost process is formed on the outer surface of the anode except for the central portion of the hermetic container 20 and the anode 21b side in advance, this light The suppressor 40 suppresses the amount of light emitted from the cathode 21a from the initial stage of the lamp life, and even if devitrification occurs on the cathode 21a side during the life,
A change in the light amount in this region can be suppressed.

FIG. 3 is a conceptual diagram of a color liquid crystal projector as one embodiment of the present invention. The color liquid crystal projector has a light projecting light source device 60 including a lamp 1 and a reflector 2 for reflecting light emitted from the lamp 1, and an optical system for condensing the light reflected by the reflector 2, for example, a light collecting device. An optical lens 3 is provided.

The light radiated forward from the condenser lens 3 is reflected by a dichroic mirror (wavelength-selective reflecting mirror) 4 which reflects blue light, and the blue light is reflected by a mirror 5 so as to reflect liquid crystal. A panel (LCD) 6 is illuminated, and the image on the liquid crystal panel 6 is colored blue and projected on a screen 10 via other dichroic mirrors 7 and 8 and a projection lens 9.

The red and green lights of the light projected from the condenser lens 3 pass through the dichroic mirror 4 that reflects the blue light, and the red light among them is reflected by another dichroic mirror 11. LCD panel 1
2, the image on the liquid crystal panel 12 is colored red, and this red image is reflected by the dichroic mirror 7, transmitted through another dichroic mirror 8, and projected on a screen 10 via a projection lens 9.

Further, the green light transmitted through the dichroic mirror 11 for reflecting the red light irradiates the liquid crystal panel 13 to color the image of the liquid crystal panel 13 green, and the green image is converted to the dichroic mirror 14 and the dichroic mirror 14. The light is reflected by a mirror 8 and projected on a screen 10 via a projection lens 9.

Therefore, by controlling the images on the three liquid crystal panels 6, 12, and 13, three-color images are projected on the screen 10 in a superimposed manner, and a color image is projected.

The light projecting light source device 60, the condenser lens 3, the dichroic mirrors 7, 8, 11, 14 and the liquid crystal panels 6, 12, 13 and the projection lens 9 are formed by a casing (not shown) like a well-known liquid crystal projector. Housed in the body.

FIG. 4 is a partial sectional side view showing a light emitting light source operating device as another embodiment of the present invention. This embodiment is an example in which the lamp axis O ₁ -O ₁ and the optical axis O ₂ -O ₂ are used in a vertical orientation.

That is, in FIG. 4, the same members as those in FIG. 1 are denoted by the same reference numerals and description thereof is omitted. However, the reflector 2 is provided in a state where the optical axes O ₂ -O ₂ are perpendicular to each other. O ₁ -O _{1 is} also vertical. In this case, in the lamp 1 connected to the DC power supply 50, the electrode 21a serving as a cathode during DC lighting is disposed on the lower side in the vertical direction, and the cathode 21a is connected to the front light emitting unit side (lower side) of the reflector 2. Are located in

It should be noted that in FIG.
The connection terminal 51 is connected to the connector 2, and the connection terminal 51 is fixed to a fixing hole 52 formed in the reflector 2. More specifically, the connection terminal 51 has a screw portion 53, which is inserted into the fixing hole 52, and a washer 54 and a nut 55 are inserted into the screw portion 53 from the rear side of the reflector 2.
And the connection terminal 51 is fixed to the fixing hole 52 by tightening the nut 55. A socket-type connector 56 is detachably connected to the connection terminal 51 on the back side of the reflector 2, and the connector 56 is connected to the DC power supply 50.

In such a configuration, when the lamp is turned on, not only the metal ions in the hermetic container 20 are attracted to the cathode 21a side due to the electric field, but also the rare-earth metal as the luminescent metal is subjected to gravity to lower. Cathode 21 located on the side
gathering in the vicinity of a, and further reducing the temperature of the cathode;
And the temperature of the lower cathode is lower due to convection, so that excess luminescent metal tends to collect on the cathode side,
Due to these combined actions, the concentration of the luminescent metal increases near the cathode 21a.

As a result, the luminescent metal is gathered on the cathode 21a side, and devitrification does not occur at the center of the hermetic container 20 or the upper anode 21b side. Therefore, a decrease in the amount of light toward the reflection surface 31 is small, and a large amount of reflected light can be secured. Therefore, the downward light amount does not decrease as the lighting time elapses.

[0042]

According to the first aspect, the ions of the luminescent metal are attracted to the cathode side and concentrated on the cathode side, so that devitrification is suppressed at the arc center and the anode side of the tube wall. At the center of the arc and the anode side of the hermetic container, the initial light transmission state is maintained. Thus, since the region of the airtight container where the light transmission state is unlikely to change over time faces the reflecting surface of the reflector, light traveling from the airtight container to the reflector is:
Since it does not easily decrease with time, the light emitted from the reflector does not easily decrease with time.

Therefore, a high light output of 40 W can be obtained.
Despite the high tube wall load of / cm ² or more, it is possible to suppress a temporal decrease in the amount of irradiation light with a simple configuration, and to prevent a decrease in illuminance on a light-emitting surface such as a screen.

According to the second aspect, the effect of the first aspect is obtained. According to the third aspect, since the light is substantially not irradiated from the tube wall on the cathode side to the irradiation object such as the screen by the light suppressing unit, even if devitrification occurs, the change in the amount of irradiation light with time is suppressed. be able to.

According to the fourth and fifth aspects, the effects of any one of the first to third aspects are achieved. According to the sixth aspect, since the cathode side is installed at a lower position, in addition to the fact that the ions of the luminescent metal are attracted to the cathode as in the first and second aspects, the luminescent metal is also acted upon by the action of gravity. It gathers in the vicinity of the cathode located on the lower side, so that devitrification is suppressed at the center and upper part of the lamp. Therefore, it is possible to suppress a decrease in the amount of irradiation light without reducing the amount of light toward the reflection surface of the reflector.

Therefore, according to the present invention, it is possible to suppress a decrease in the amount of reflected light due to devitrification, to suppress a decrease in illuminance on a screen with the lapse of time with a simple configuration, and to obtain a high light output. It is possible to provide an apparatus, a light source operating device and a liquid crystal projector.

[Brief description of the drawings]

FIG. 1 is a partially sectional side view showing a light emitting light source operating device as one embodiment of the present invention.

FIG. 2 is a life characteristic diagram showing an illuminance reduction ratio on a screen.

FIG. 3 is a conceptual diagram of a color liquid crystal projector as one embodiment of the present invention.

FIG. 4 is a partially sectional side view showing a light emitting light source operating device as another embodiment of the present invention.

FIG. 5 is a perspective view showing the related art with a part cut away.

[Explanation of symbols]

 Reference Signs List 20 airtight container 21a electrode operating as cathode 21b electrode operating as anode 1. metal halide lamp 2. reflector 6, 12 liquid crystal panel

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Ichiro Tanaka 1-4-2, Mita, Minato-ku, Tokyo Inside Toshiba Litec Corporation (56) References JP-A-49-108876 (JP, A) JP-A-Hei 4-32154 (JP, A) JP-A-62-35403 (JP, A) Japanese Utility Model Application Laid-open No. 4-21051 JP, U) US Patent 5,107,165 (US, A) European Patent Application Publication 501,668 (EP, A) (58) Field surveyed (Int.Cl. ⁶ , DB name) H01J 61/88

Claims (6)

(57) [Claims] 1. A quartz glass of the airtight container, a metal halide sealed in the pair of electrodes and hermetic containers FuSo inside both ends of the container, with mercury and rare gas,
A metal halide lamp that is DC-lit so that the tube wall load is 40 W / cm ² or more; and a light-transmitting opening, such that the electrode that operates the metal halide lamp as its cathode is positioned on the light-transmitting opening side. And a stored reflector. 2. A quartz glass of the airtight container, FuSo cathodic on one end of the vessel, a metal halide sealed in the FuSo anodes and hermetic container at the other end, with mercury and a rare gas, the tube A metal halide lamp configured to be operated to have a wall load of 40 W / cm ² or more; a metal halide lamp having a bowl shape having a light-transmitting opening, and an anode of the metal halide lamp and a cathode being disposed on the bottom side of the bowl shape. And a reflector which accommodates the metal halide lamp and is positioned on the light opening side. 3. A quartz glass of the airtight container, one end FuSo cathodic of the vessel, a metal halide sealed in the FuSo anodes and hermetic container at the other end, provided with a mercury and rare gas, A metal halide lamp having a light-suppressing means on the surface of the airtight container on the light-transmitting opening side; a bowl having a light-transmitting opening, wherein the anode of the metal halide lamp is on the bottom side of the bowl, and the cathode is the light-transmitting opening. And a reflector that accommodates the metal halide lamp and is positioned on each side. 4. A light projecting light source device according to claim 1 or 2, and a direct current power supply for stably forming a discharge between electrodes of the metal halide lamp of the light projecting light source device. A light projection light source operating device, characterized in that: 5. The light-projecting light source operating device according to claim 4, an optical system for projecting light from the light-projecting light source device onto a screen, and a liquid crystal panel disposed in the optical system. A liquid crystal projector, comprising: a light emitting light source operating device, an optical system, and a housing for housing the liquid crystal panel. 6. The liquid crystal projector according to claim 5, wherein the reflector is provided so that the light transmission opening faces downward.