JP2003123529A - Light source unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optimal light source unit for a liquid crystal projector providing desired lamp characteristics by cooling the interior of the light source unit while preventing excessive cooling at the lower part of a discharge container of a discharge lamp regardless of the service state of the liquid crystal projector. SOLUTION: In this light source unit 10, ventilating holes 11, 12 are provided to allow cooling air to flow into a concave reflecting mirror 20 from the front side of the light source unit 10 and to be exhausted from the vicinity of a neck part 24, and the discharge lamp 20 is arranged in the coinciding state of the optical axis of the concave reflecting mirror 20 and the optical axis of the discharge lamp 30 so as to light the discharge lamp 20 in a nearly horizontal state. Further, an external lead rod 33 is rotatably provided with a cooling air shielding member 60 for shielding the cooling air flowing toward the lower part of a light emitting part 31.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source unit for a so-called backlight that illuminates a liquid crystal panel of a liquid crystal projector, and more particularly to a light source unit for a liquid crystal projector that can be applied to both floor installation and ceiling suspension.

[0002]

2. Description of the Related Art Liquid crystal projectors are widely used due to the increasing need for displaying images on a personal computer or a television on a large screen and the technological development related to liquid crystals. Depending on the application and location of this LCD projector, there are those that are used by placing it on the floor or desk, and those that are hung from the ceiling. Recently, there are also those that can be used for both. It has become widely known. This liquid crystal projector for both stationary and ceiling suspension (hereinafter also referred to as "dual-use liquid crystal projector") is a device that is turned upside down when switching from the stationary state to the suspended state. And project the projected image 18
Rotate 0 degrees. This reason is related to the difference in the projection method of the liquid crystal projector.
A brief explanation will be given with reference to. 8A and 8B are schematic diagrams for explaining the projection method of the liquid crystal projector. FIG. 8A is an explanatory drawing in a state of being laid on the floor, and FIG. 8B is an explanatory drawing in a state of being suspended from the ceiling. is there. When the liquid crystal projector is used in a stationary state as shown in FIG. 8 (a), the front projection lens L is mounted upward so as to project an image on the screen S located in front of and above the lens. The angle θ ₁ shown therein is set in the range of 11 to 15 °. Then, when the liquid crystal projector is hung from the ceiling as shown in FIG. 8B, the projection lens L is attached so as to be inclined downward so as to project an image on the screen S positioned in front of and below this, The angle θ ₂ shown in the figure is set to be about 11 to 15 °.

As described above, the angle of the projection lens is approximately vertically symmetrical between when it is used in a stationary state and when it is suspended from the ceiling. By reversing the top and bottom of the image and rotating the image by half, the complicated adjustment of the projection lens is not required, and it is possible to easily switch each use state.

As an illumination light source of the liquid crystal projector as described above, a light source unit in which a concave reflecting mirror is combined with a discharge lamp for a light source such as an ultra-high pressure mercury lamp or a metal halide lamp is generally used. 2. Description of the Related Art A so-called hermetically sealed light source unit in which a front plate made of a translucent material is provided in a front (light emission side) opening of the concave reflecting mirror has been used. The front plate is to prevent the explosion sound of the discharge lamp built into the light source unit from being blown off and the fragments of the discharge vessel from scattering around even if the discharge lamp should burst. It plays a role to prevent external influence.

[0005]

However, since the discharge lamp built in the light source unit as described above is hermetically sealed by the concave reflecting mirror and the front plate, the discharge lamp and its vicinity are lit when used for a long time. May overheat, causing various problems such as devitrification of the discharge vessel, peeling of the multilayer film on the inner surface of the concave reflecting mirror, and further cracking of the concave reflecting mirror.

In view of such circumstances, the present applicant has proposed a light source device having cooling means for efficiently cooling the mirror surface of the concave reflecting mirror and the discharge lamp even if it is a so-called hermetic type light source unit (see Kai 2000-082211). The technique according to the present invention will be described with reference to FIG. A ventilation hole 3A for inflow of cooling air is formed in a lower portion 2A of the front opening peripheral edge portion 2 of the concave reflecting mirror 1, and the cooling air is collected from the ventilation hole 3A above the concave reflecting mirror 1. Is flowed toward. On the other hand, a ventilation passage 6 is formed at the rear end of the concave reflecting mirror 1 by a gap between the concave reflection mirror 1 and the sealing portion 5 of the discharge lamp 4, and a ventilation hole 3B for exhaust air through which cooling air can flow is formed in the holder 7. ing. According to the present invention, the upper portion of the discharge lamp 4 that tends to overheat inside the light source unit 8 can be cooled with high efficiency.

When the liquid crystal projector incorporating the light source unit (8) according to the above invention is turned upside down, the light source unit 8 changes from the state shown in FIG. 9 to the state shown in FIG. A larger amount of cooling air flows toward the lower side of the concave reflecting mirror 1 which is located above the light source unit 8. As a result, the discharge lamp 4 has an upper part 4
Compared to A, the lower portion 4B is cooled more efficiently. When the lower part 4B of the discharge lamp 4 is cooled, the enclosed material such as mercury enclosed in the lamp is in a non-evaporated state, aggregates, and accumulates in the coldest part.
The operating pressure of the discharge lamp 4 decreases, and desired lamp characteristics cannot be obtained. Specifically, the desired brightness cannot be obtained, and further, the light flux cannot be stably maintained.

As a result, there is a problem in that the image projected from the liquid crystal projector on the screen becomes uneven or flickers. In recent years, it has been preferred to use a discharge lamp having a higher operating pressure, and this tends to increase the amount of mercury enclosed. To give an example, the enclosed amount of mercury is 0.16 m.
g / mm ³ or more, and in such a discharge lamp with a high mercury filling amount, it is necessary to maintain the zero point of the arc tube when the lamp is lit relatively high. Specifically, it is preferable to keep the temperature at about 750 ° C or higher. Therefore, the present invention, regardless of the state of use of the liquid crystal projector, the inside of the light source unit, while preventing excessive cooling in the lower portion of the light emitting portion of the discharge lamp, while cooling other parts with high efficiency,
It is an object of the present invention to provide a light source unit that is suitable for liquid crystal projector applications and that can obtain desired lamp characteristics.

[0009]

In order to solve the above-mentioned problems, the present invention is directed to a discharge lamp, a concave reflecting mirror for reflecting light emitted from the discharge lamp forward, and a front opening of the concave reflecting mirror. A front plate that blocks the light and emits the reflected light,
In the light source unit having, a ventilation hole is provided in the light source unit so that cooling air flows into the concave reflecting mirror from the front of the light source unit and is discharged from the vicinity of the neck, and the discharge lamp is An optical axis of the concave reflecting mirror and an optical axis of the discharge lamp are arranged so as to be lit in a substantially horizontal state, and the lower part of the light emitting part is attached to the external lead rod located in front of the light emitting part. It is characterized in that a cooling air shielding member for shielding the cooling air traveling toward is rotatably attached. The cooling air shielding member is preferably rotated by its own weight.

[0010]

DETAILED DESCRIPTION OF THE INVENTION The present invention will be described in detail below with reference to the drawings. 1A and 1B show an internal configuration of the dual-purpose liquid crystal projector device when the device is stationary, where FIG. 1A is a front view and FIG. 1B is a left side view. LCD projector
P is basically a light source unit 10, an optical lens unit (not shown) that optically processes light emitted from the light source unit 10, a projection lens L that magnifies and projects the light flux processed here, and a ventilation fan. It is configured by including F1 and F2, a power supply unit (not shown), and the like. When the dual-use liquid crystal projector P is hung from the ceiling and used, the top and bottom are reversed, so the P1 surface is located on the lower side and the P2 surface is located on the upper side.

In the above structure, the light source unit 10
Is arranged such that the optical axis of the emitted light is horizontal when in use, and the optical axis is orthogonal to the optical axis of the projection light emitted from the projection lens L through an appropriate optical system. They are arranged in a positional relationship. FIG. 1A is a right side view of the light source unit, and FIG. 1B is a front view of the light source unit. For example, a fan F2 is arranged on the light extraction side of the light source unit 10, and the air from the fan F2 is formed in a front portion of the light source unit 10 through a ventilation hole 1
1 is introduced into the inside of the light source unit, flows through the inside of the light source unit, and is sucked by the suction fan F1.
The air is discharged from the other ventilation hole 12 formed in the rear portion of the liquid crystal projector, and is further discharged to the outside of the liquid crystal projector device.

An embodiment of the present invention will be described with reference to FIG. 2A and 2B are enlarged sectional views for explaining the light source unit 10 shown in FIG. 1, where FIG. 2A shows a stationary state and FIG. 2B shows a suspended state. First, the configuration of the light source unit according to the embodiment of the present invention will be described with reference to FIG. In the figure, the light source unit 10 includes a concave reflecting mirror 20 having an opening in front of which light is emitted (left side in the figure), a discharge lamp 30 formed of a high pressure mercury lamp,
A holder 40 for holding the discharge lamp 30 and a front plate 50 made of a translucent material for closing the front opening of the concave reflecting mirror 20.
And is configured. The concave reflecting mirror 20 is made of, for example, borosilicate glass, and has a concave condensing portion 21 that forms a space for condensing the light emitted from the discharge lamp 30, and a tube that extends forward from the condensing portion 21. Shaped part 2
2, a front outer edge portion 23 formed at the front end of the tubular portion 22 to form a light emitting port, and a neck portion 24 through which the one sealing portion 32B of the discharge lamp 30 is inserted at the center of the condensing portion 21. And are formed. On the inner surface of the condensing portion 21 of the concave reflecting mirror 20, for example, titania (TiO ₂ ) and silica (SiO ₂ ) are laminated to transmit light in the ultraviolet region and infrared region and reflect only visible light. A reflective surface made of a film is formed.

A sealing portion 32B behind the discharge lamp 30.
For example, a base 30B is attached to an end of the concave reflector 20 and is inserted into the neck portion 24 of the concave reflecting mirror 20, and the concave reflecting mirror 20 and the discharge lamp 30 are fixed so that their optical axes coincide with each other.

FIG. 3 is an enlarged explanatory view of the mounting portion of the cooling air shield member 60 shown in FIG. 2 (a).
The external lead rod 33 projects from the tip surface of the sealing portion 32A of the discharge lamp 30, and the lead wire 34 is connected to the tip portion. The external lead rod 33 is electrically connected to the electrode 37 exposed in the discharge space via the molybdenum foil 35 embedded in the sealing portion 32A and the internal lead rod 36.

The cooling air shielding member 60 is held by inserting the external lead rod 33 into the lead rod insertion hole 61 between the sealing portion 32A and the lead wire 34.
The cooling wind shielding member 60 is rotatable about the outer lead rod 33 as a rotation axis, and when the discharge lamp 30 is held in a substantially horizontal posture, the wing portion 62 of the cooling wind shielding member 60 is turned on. The discharge lamp 30 hangs down due to its own weight and is positioned below the light emitting portion 31 of the discharge lamp 30.

FIG. 4 shows an example of the form of the cooling air shielding member 60, showing (a) a plan view and (b) a side view. The blade portion 62 of the cooling air shielding member 60 is formed with a slightly wide surface and is bent forward in the rotation axis direction. In consideration of heat resistance and workability, a metal having a relatively high melting point is preferable as the material of the cooling air shielding member 60, and for example, stainless steel material, aluminum or the like can be used. Alternatively, ceramics may be used.

Now, referring again to FIG. 2, the route of the cooling air will be described. In the stationary state of FIG. 2 (a),
In the light source unit 10, from the lower side portion of the front outer edge portion 23 toward the upper reflecting surface of the concave reflecting mirror 20, a ventilation hole 11 formed by cutting out a part of the lower side portion of the front outer edge portion 23, For example, as shown by the arrow in the figure, the concave reflecting mirror 2
When the cooling air is introduced toward the inner surface on the upper side of 0, as for the cooling air that is introduced to the lower portion of the light emitting portion 31, the cooling air shielding member 60 of the concave reflecting mirror 20 is used. Guided to the upper side. As a result, cooling of the lower part of the light emitting unit 31 is suppressed, and other parts are cooled with high efficiency. Ultimately, the cooling air concerned
After passing through the gap between the neck portion 24 of the concave reflecting mirror 20 and the sealing portion 30B of the discharge lamp 30, the air is discharged from the ventilation hole 12 formed in the holder 40, for example.

When the liquid crystal projector is switched from the stationary state to the suspended state, that is, when the top and bottom are inverted, the light source unit 10 becomes the state shown in FIG. 2 (b),
The cooling air flows through the front outer edge portion 23 of the light source unit 10.
From the upper part of the concave reflecting mirror 20 toward the lower part thereof. Here, according to the present embodiment, as described above, the cooling air shielding member 60 is the external lead rod 3.
Since it is rotatably attached to the shaft 3, the wing portion 62 is always positioned downward by its own weight to shield the cooling air flowing toward the lower side portion of the light emitting portion 31, and to direct it to other portions. It becomes possible to guide the cooling air. as a result,
The cooling air is not directly blown to the lower portion of the light emitting portion 31, and therefore, excessive cooling is suppressed at the relevant portion, and the other portions are cooled with high efficiency. The cooling air finally passes through the same passage as described above and is discharged from the ventilation hole 12.

As described above, according to the light source unit according to the present invention, the lower part of the cooling air from the front of the light source unit in the light emitting portion of the discharge lamp is provided by the cooling air shielding member rotatably held. For the air blown toward, the light is guided so that it does not directly hit the lower part of the light emitting part, and the other parts are cooled with high efficiency, so that the operating pressure of the discharge lamp is not lowered and uneven light emission occurs. Since it is possible to prevent it, a predetermined light output can be stably obtained, and the effect can be obtained regardless of the usage state of stationary / suspended in the liquid crystal projector. Therefore, the stationary / suspended liquid crystal projector can be used. It becomes possible to use it suitably for.

FIGS. 5 to 7 are schematic views showing another embodiment of the cooling air shield member 60. The cooling air shielding member 60 shown in FIG. 5 is a flat plate and is molded into a substantially circular overall shape. The external lead rod insertion hole 61 is provided in the cooling air shielding member 60.
Is formed at a position deviated from the center (center of gravity) of the light source unit 10, and when the discharge lamp 30 is attached to a predetermined position of the light source unit 10, the wing portion 62 always hangs down when the discharge lamp 30 is in a substantially horizontal posture. To cover the lower part of.

The shape of the cooling air shielding member is arbitrary and can be changed in various ways. For example, as shown in FIG. 6, the cooling air shielding member may be configured so as to be slightly wider at a position located below the light emitting portion. . The point is that the lead rod insertion hole 61 may be formed at a position deviated from the center of gravity of the cooling air shield member 60.

The wing portion (62) may be bent. For example, as shown in the side view of FIG. 7, when molded in the direction of the light emission port in the direction of the rotation axis (that is, in the direction opposite to the light emitting portion), from the front of the light source unit (on the paper surface, It is preferable because the cooling air that has flowed in (in the direction from left to right) can be guided away from the light emitting unit 31.

If the size of the cooling air shielding member is such that it does not exceed the size of the maximum outer diameter portion of the arc tube when the light source unit is viewed from the front, the cooling air shielding member is removed from the concave reflecting mirror. It is preferable because the reflected light is not blocked and the light can be efficiently emitted.

Further, when the cooling air shielding member has a light-reflecting property on its back surface, the light reflected by the cooling air shielding member warms the lower portion of the light emitting portion to raise the temperature of the portion. As a result, it is possible to reduce the temperature unevenness of the light emitting portion and expect further increase in the light output.

[0025]

As described above, according to the present invention,
It is possible to cool the inside of the light source unit regardless of the direction of the top and bottom and prevent overcooling in the lower part of the light emitting part of the discharge lamp, so that the lighting characteristics of the discharge lamp are not impaired, that is, the desired The brightness can be obtained and the luminous flux can be stably maintained. Therefore, in the liquid crystal projector incorporating the light source unit according to the present invention, it becomes possible to prevent image unevenness and flicker.
A light source unit suitable for use as a liquid crystal projector can be provided.

[Brief description of drawings]

FIG. 1 is a diagram showing an internal configuration of a dual-purpose liquid crystal projector device when the device is installed (a) front view, (b).
It is a left side view.

FIG. 2 (a) is a stationary state of the light source unit shown in FIG.
(B) It is sectional drawing for description at the time of suspension.

FIG. 3 is an explanatory schematic diagram in which a mounting portion of a cooling air shielding member at the time of stationary of FIG. 2A is enlarged.

FIG. 4 is a diagram showing an example of the form of a cooling air shielding member, (a) a plan view and (b) a side view.

5 (a) is a plan view and FIG. 5 (b) is a side view showing another example of the form of the cooling air shielding member.

6A and 6B are diagrams showing another example of the form of the cooling air shielding member, FIG. 6A is a plan view and FIG. 6B is a side view.

7 (a) is a plan view and FIG. 7 (b) is a side view showing another example of the form of the cooling air shielding member.

FIG. 8 is a schematic diagram illustrating a projection method of a liquid crystal projector.

FIG. 9 is a diagram illustrating an example of a closed-type light source unit according to a conventional technique.

FIG. 10 is a diagram illustrating a state in which the light source unit shown in FIG. 9 is turned upside down.

[Explanation of symbols]

10 Light source unit 11, 12 ventilation holes 20 concave reflector 21 Focusing area 22 Cylindrical part 23 Front outer edge 24 neck 30 discharge lamp 30B base 31 Light emitting part 32A, 32B Sealing part 33 External lead rod 34 lead wire 35 molybdenum foil 36 internal lead rod 37 electrodes 40 holder 50 front plate 60 Cooling air shielding member 61 Lead rod insertion hole

Front page continuation (51) Int.Cl. ⁷ identification code FI theme code (reference) G03B 21/16 F21M 7/00 L H04N 5/74 1/00 R // F21Y 101: 00

Claims (2)

[Claims] 1. A light source comprising: a discharge lamp; a concave reflecting mirror for reflecting light emitted from the discharge lamp forward; and a front plate for closing the front opening of the concave reflecting mirror and emitting the reflected light. In the unit, a ventilation hole is provided in the light source unit so that cooling air flows into the concave reflecting mirror from the front of the light source unit and is discharged from the vicinity of the neck, and the discharge lamp is in a substantially horizontal state. The optical axis of the concave reflecting mirror and the optical axis of the discharge lamp are arranged so as to be turned on by an external lead rod located in front of the light emitting portion of the discharge lamp, and A light source unit, wherein a cooling air shielding member for shielding cooling air directed to a portion is rotatably attached. 2. The light source unit according to claim 1, wherein the cooling air shield member is rotated by its own weight.