JPH09288902A - Light source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source device for a liquid-crystal projector which can prevent the shadow of the conducting wiring of a lamp from clearly appearing on a screen even if an integrator lens is used. SOLUTION: This device includes a metal halide lamp 10 of the sealed-end type, in which sealing parts 12, 13 are integrated with both ends of a light- emitting tube 11, and a concave reflector 20, one 12 of the sealing parts of the lamp being mounted and held in an opening 21 at the root of the concave reflector, the other sealing part 13 being extended toward an opening 22 at the end of the concave reflector. In this case, conducting wiring 30 located on the sealing part 13 extended toward the opening 22 at the end of the concave reflector is oriented toward the light emitting tube 11 along the sealing part 13 and is then spaced from the light emitting tube 11 from its position near the light emitting tube 11, so that the distance between the portion 32 of the conducting wiring 30 which receives the light reflected by the concave reflector 30 and which is spaced from the light emitting tube 11 and an integrator lens is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source device for a liquid crystal projector that uses a short arc metal halide lamp with both ends sealed as a light source.

[0002]

2. Description of the Related Art A short arc metal halide lamp with both ends sealed is a quartz glass arc tube having a pair of electrodes with an inter-electrode distance of about several millimeters inside, along with mercury, a rare gas for starting, and a luminous metal. A metal halide is enclosed as. The seal portion is integrally connected to both ends of the arc tube, and molybdenum foil in which one end of the electrode and one end of the external lead rod for power supply are welded to both ends is embedded in the seal portion. Extends from the seal portion.

Since such a metal halide lamp evaporates a metal halide, a sufficient vapor pressure can be obtained at a lower temperature as compared with the case of a single metal, the luminous efficiency is excellent as compared with a high pressure mercury lamp, and an enclosed metal is appropriately used. Since excellent color rendering can be obtained by selection, it is often used for a light source lamp of a light source device for a liquid crystal projector.

A light source device for a liquid crystal projector is shown in FIG.
As shown in FIG. 2 and FIG. 2, the both ends sealed type short arc metal halide lamp 10 and a base end opening 21 at the center are provided.
The concave reflecting mirror 20 having a metal halide lamp 10 is provided with a filler at one end of the sealing portion 12 of the metal halide lamp 10 in a state where the optical axis of the concave reflecting mirror 20 and the optical axis of the concave reflecting mirror 20 are substantially aligned with each other. The metal halide lamp 10 is held by being attached by embedding it. Therefore, the other seal portion 13 of the metal halide lamp 10 extends in the direction of the front end opening 22 of the concave reflecting mirror 20, and the end portion of the conductive wire 30 is connected to the external lead rod 15 extending from this seal portion 13. .

As shown in FIG. 1, the conductive wiring 30 connected to the external lead bar 15 whose end extends from the seal portion 13 once rises in the vertical direction, then extends in parallel with the metal halide lamp 10, and has a concave surface. Base end opening 21 of reflector 20
It is pulled out to the back side of the concave reflecting mirror 20 through the. Alternatively, as shown in FIG.
It rises from the end of 3 and draws a large arc, and is drawn out to the back side of the concave reflecting mirror 20 through a drawing hole 24 formed in the reflecting surface 23 of the concave reflecting mirror 20. That is, in any case, the conductive wiring 30 is connected to the metal halide lamp 10.
It is arranged in a state where it rises from the end of the seal portion 13 and is largely separated from the seal portion 13 and the arc tube 11.

Next, in the liquid crystal projector device, as shown in FIG. 3, the parallel light reflected by the concave reflecting mirror 20 enters the liquid crystal panel 60 through the condenser lens 51,
The image of the liquid crystal panel 60 is formed on a screen (not shown) by the projection lens 52, but recently, in order to make the illuminance distribution on the screen as uniform as possible, the concave reflecting mirror 20 of the light source device and the condenser lens 51 are formed. An incident side lens 41 in which a plurality of lens elements are arranged in a plane
Further, a liquid crystal projector device in which an integrator lens 40 including a pair of lenses of the emission side lens 42 is arranged is becoming mainstream. In addition to the above components, components such as a color filter and a polarizing element are arranged as necessary.

In the integrator optical system, the lens element of the incident side lens 41 is imaged on the liquid crystal panel 60 by the emission side lens 42. Therefore, the light emitted from the integrator lens 40 is a combination of the illuminance distributions of the light emitted from the plurality of lens elements forming the integrator lens 40, that is, the light emitted from each lens element has a gentle mountain shape. Since the illuminance distribution curve is synthesized by shifting the illuminance distribution curve little by little, the illuminance distribution curve becomes close to flat, and the illuminance on the screen can be made uniform.

[0008]

As described above, since the lens element of the incident side lens forms an image on the liquid crystal panel by the emitting side lens, the incident side lens is also called a second light source. Therefore, when an object exists near the incident side lens which is the second light source, an image of the object is formed on the liquid crystal panel and appears as a shadow on the screen. The closer the distance between the object and the incident side lens is, the clearer the image becomes. It becomes a shadow.

By the way, also in the liquid crystal projector device, the distance between the light source device and the incident side lens of the integrator lens is designed to be as short as possible in order to reduce the size.
The distance from the tip of the concave reflecting mirror to the incident side lens of the integrator lens is about 20 mm. Then, as described above, since the conductive wiring connected to the external lead rod extending from the seal portion extending in the opening direction of the tip of the concave reflecting mirror rises from the end portion of the seal portion, the conductive wiring is erected. The distance from the raised portion to the incident side lens is about 10 mm, which is extremely short. Therefore, there is a problem that the shadow of the conductive wiring appears clearly on the screen.

Therefore, when the length of the seal portion of the metal halide lamp is shortened, the distance between the conducting wire and the lens on the incident side is increased by that much, and the shadow on the screen becomes thin, but the tube wall load is large and the temperature becomes extremely high during lighting. For metal halide lamps, shortening the seal length
The molybdenum foil embedded in the seal part oxidizes at high temperature and shortens the lamp life. Therefore, there is a limit to shortening the length of the seal portion and thinning the shadow.

Therefore, the present invention can prevent the shadow of the conductive wiring of the metal halide lamp from clearly appearing on the screen even if the integrator lens is used in order to make the illuminance distribution on the screen nearly uniform. An object is to provide a light source device for a liquid crystal projector.

[0012]

In order to achieve the above object, the present invention provides an arc tube made of quartz glass, which has a pair of electrodes inside and in which a metal halide is enclosed together with mercury and a rare gas for starting. Seal parts are integrally provided on both ends,
The external lead rod is provided with a short arc metal halide lamp extending from the seal portion, and a concave reflecting mirror having a base end opening in the central portion, and in a state where the axis of the lamp and the optical axis of the concave reflecting mirror are substantially aligned with each other, In a light source device in which one seal part of the lamp is attached to the base end opening and the other seal part extends in the front end opening direction of the concave reflecting mirror, extends from the seal part extending in the front end opening direction of the concave reflecting mirror. Conductive wiring connected to the external lead bar is arranged along the seal part toward the arc tube, and is pulled out from the position near the arc tube to the back side of the concave reflecting mirror, apart from the arc tube. To do so.

That is, the conductive wiring connected to the external lead rod extending from the seal portion extending in the opening direction of the tip of the concave reflecting mirror is arranged in the direction of the arc tube along the seal portion. The distance between the rising portion of the conductive wire, which is separated from the arc tube, and the incident-side lens of the integrator lens is longer than that of the conventional one by the distance along the seal portion. Therefore, the image of the conducting wire formed by the exit side lens of the integrator lens is largely separated from the liquid crystal panel, and as a result, the shadow of the conducting wire on the screen becomes extremely thin.

[0014]

Embodiments of the present invention will be specifically described below with reference to the drawings. In FIG. 4, the both ends sealed type short arc metal halide lamp 10 is composed of a quartz glass arc tube 11 and seal portions 12 and 13 continuously provided at both ends thereof. In the arc tube 11, a pair of electrodes is provided. The metal halides such as Dy, Nd, Lu, and Cs are enclosed together with mercury and a rare gas for starting, which are opposed to each other with a space of several mm. Molybdenum foil is embedded in the seal portions 12 and 13, the base 16 is attached to one of the seal portions 12, and the conductive wiring 35 is connected to the seal portion 12.
Is connected to an external lead rod (not shown) extending from the other end, and an external lead rod 15 electrically connected to the electrode via the molybdenum foil extends from the other seal portion 13 and is connected to the conductive wiring 30. . The short arc metal halide lamp 10 has a pair of conductive wires 30, 3
Power is supplied at 5, and DC lighting is performed at a rated power of 250W.

The concave reflecting mirror 20 is an elliptical mirror having a tip opening 22 with an inner diameter of 84 mmφ, the inner surface of its spheroid is a reflecting surface 23, and a base end opening 21 is provided at the center. Then, as described above, the metal halide lamp 10 is attached and held by a method such as burying the one seal portion 12 of the metal halide lamp 10 in the base end opening 21 using a filler. Therefore, the other seal portion 13 of the metal halide lamp 10 projects toward the tip opening 22 of the concave reflecting mirror 20. At this time, the axis of the metal halide lamp 10 and the optical axis of the concave reflecting mirror 20 are aligned with each other, the arc center of the metal halide lamp 10 is positioned at the focal point of the concave reflecting mirror 20, and the reflected light of the concave reflecting mirror 20 is collimated into an integrator. It is designed to illuminate the lens.

One end of the conductive wire 30 is connected to the external lead bar 15 as described above, but the conductive wire 30 is
The straight line portion 31 and the semi-circular arc portion 32 are in contact with the seal portion 13, and are arranged along the longitudinal direction of the seal portion 13 toward the arc tube 11. Therefore, the reflected light of the concave reflecting mirror 20 does not strike the straight line portion 31. Here, the length a of the straight portion 31 is, for example, 20 mm.
Then, the semi-circular arc portion 32 on which the reflected light of the concave reflecting mirror 20 strikes
Is arranged concentrically with the arc tube 11 and is spaced apart from the arc tube 11 by, for example, 5 mm, and the conductive wiring 30 is drawn out from the base end opening 21 to the back side of the concave reflecting mirror 20.

Alternatively, as shown in FIG.
Is composed of a straight line portion 31 that is in contact with the seal portion 13 and a large arc portion 33 that is separated from the arc tube.
It may be pulled out to the back side of the concave reflecting mirror 20 from the pull-out hole 24 formed in the hole 3. Also in this case, the large circular arc portion 33 is exposed to the reflected light of the concave reflecting mirror 20, but the linear portion 31 is not exposed to the reflected light of the concave reflecting mirror 20.

As described above, the semi-circular arc portion 32 or the large arc portion 33 of the conductive wiring 30 on which the reflected light of the concave reflecting mirror 20 strikes.
Is located in the direction of the arc tube 11 from the end of the seal portion 13 by the length a of the straight portion 31, so that the semi-circular arc portion 32 or the large circular arc portion 33 of the conducting wire 30 and the incident-side lens of the integrator lens 40. The distance from 41 is longer than the conventional length a.
Only longer. Therefore, the image of the conducting wire 30 formed by the exit side lens 42 of the integrator lens 40 is largely separated from the liquid crystal panel 60, and the shadow of the conducting wire 30 on the screen is extremely thin.

Next, the result of actual measurement of the illuminance distribution in the shaded portion of the conductive wiring on the screen will be described. The light source device used is that shown in FIG. 4, and the distance between the tip of the seal part 13 and the incident side lens 41 of the integrator lens 40 is 10 mm, and the length a is 20 mm. Then, as a conventional example, the light source device shown in FIG. 1 was used. The black portion of FIG. 6 shows the shadow of the conductive wiring on the screen,
The illuminance in the AA 'direction was measured, and the center of the shadow was set as the measurement point 0. The results are shown in FIG. 7, and the illuminance is displayed as a relative value when the illuminance at measurement point 0 in this example is 100.

As can be seen from the above, in the conventional example, the illuminance distribution curve has a valley shape in which the illuminance is lowest at the measurement point 0, which is the center of the shadow of the conductive wiring, and the shadow of the conductive wiring is clearly visible. It indicates that On the other hand, the illuminance distribution curve of this example is almost linear, indicating that the shadow of the conductive wiring is hardly recognized on the screen.

[0021]

As described above, according to the present invention, the conductive wiring connected to the external lead rod extending from the seal portion extending in the opening direction of the tip of the concave reflecting mirror is provided along the seal portion. The lamp is placed in the direction of the arc tube, and it is pulled out from the position near the arc tube to the back side of the concave reflecting mirror, apart from the arc tube, so that the illuminance distribution on the screen is made nearly uniform. Even if a lens is used, it is possible to provide a light source device for a liquid crystal projector capable of preventing the shadow of the conductive wiring of the metal halide lamp from appearing on the screen.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a conventional example.

FIG. 2 is a cross-sectional explanatory view of a conventional example.

FIG. 3 is an explanatory diagram of a liquid crystal projector device.

FIG. 4 is a sectional view of the present embodiment.

FIG. 5 is a sectional view of another embodiment.

FIG. 6 is an explanatory diagram of shadows on the screen.

FIG. 7 is an explanatory diagram of an illuminance distribution in a shadow portion on the screen.

[Explanation of symbols]

 10 Short Arc Metal Halide Lamp 11 Arc Tube 12, 13 Sealing Part 15 External Lead Rod 20 Concave Reflector 21 Base End Opening 22 Tip Opening 23 Reflecting Surface 24 Extraction Hole 30 Conductive Wiring 31 Straight Wire Part 32 Conductive Wiring Half Arc Part 33 Large Arc of Conductive Wiring 40 Integrator Lens 41 Incident Side Lens 42 Emission Side Lens 51 Condenser Lens 52 Projection Lens 60 Liquid Crystal Panel

Claims (1)

[Claims] 1. A seal part is integrally connected to both ends of an arc tube made of quartz glass in which a pair of electrodes are provided inside, and mercury and a rare gas for starting are enclosed together with a metal halide. A short arc metal halide lamp extending from the seal portion and a concave reflecting mirror having a base end opening in the central portion are provided, and one seal of the lamp is provided with the axis of the lamp and the optical axis of the concave reflecting mirror substantially aligned with each other. In the light source device in which the part is attached to the base end opening and the other seal part extends in the front end opening direction of the concave reflecting mirror, an external lead rod extending from the seal part extending in the front end opening direction of the concave reflecting mirror is provided. Conductive wiring to be connected is arranged toward the arc tube along the seal portion,
A light source device, characterized in that the light source device is pulled out from a position near the arc tube to the back side of the concave reflecting mirror while being separated from the arc tube.