JPH0473636A - Light projecting light source device - Google Patents

Abstract

PURPOSE:To reduce the variation of the brightness of a reflected light by displacing and arranging an intermediate point between the electrodes of a lamp lighted in an almost horizontal posture downward with respect to the optical axis of a reflector. CONSTITUTION:The axis O1 - O1 of the lamp is inclined and disposed so that it is biased downward with respect to the optical axis O2 - O2 of the reflector 2. Besides, the intermediate point P between the electrode 11a and the electrode 11b is displaced and arranged by facing it toward the lower side from the optical axis O2 - O2. Therefore, in the case that the center of emitting light by the bending of an arc is biased upward, it just aligns with the optical axis O2 - O2 of the reflector 2 or extremely approaches it. Thus, the center of the emitting light is positioned on the optical axis O2 - O2 which passes through a focusing position when it is seen from the reflector 2. As the result, since the top and bottom and the left and right variation of the reflected light is eliminated, the variation of the brightness is eliminated extending over the whole surface.

Description

DETAILED DESCRIPTION OF THE INVENTION [Objective of the Invention (Industrial Application Field) The present invention relates to a projection light source device that uses a metal halide lamp as a light source and is effective when applied to an image projection device such as a projector device.

(Prior Art) As shown in FIG. 5, an image projection device such as a liquid crystal projector device includes a light source 1 and a reflector 2 that accommodates the light source 1 and reflects and focuses light emitted from the light source 1. ,
For example, in the case of a liquid crystal projector device, the projector is equipped with an optical lens 4 that projects the light collected by the reflector 2 onto a projection surface such as a screen 3.
A liquid crystal display screen 5 is provided in front of the optical system lens 4, and images such as characters, tables, figures, etc. displayed on the liquid crystal display screen 5 are enlarged and projected onto the screen 3.

In such an image projection apparatus, a halogen light bulb has conventionally been used as a light source because a predetermined light output is required. However, since halogen light bulbs emit light from the incandescence of a filament, they have problems such as a small amount of light, low luminous efficiency, and poor life characteristics.

Increasing the amount of light from a halogen bulb requires increasing the size of the filament, which increases the size of the lamp, resulting in an increase in the size of the entire image projection device.

For this reason, metal halide lamps have recently been increasingly used as light sources. Metal halide lamps have high luminous efficiency, long life, and excellent color rendering properties, so they have the advantage of greatly contributing to miniaturization of light sources.

As shown in FIG. 4, the metal halide lamp has a pair of electrodes 11a and 11b sealed in an arc tube 10 made of quartz glass or the like so as to face each other, and these electrodes 11a and 11b are connected to the outside via metal foil conductors 12 and 12. It is connected to lead wire 13.13. This metal halide lamp is of a both-end sealed type, with sealing portions 14 at both axial ends of the arc tube 10.
14 are formed, and the metal foil conductor 12.12 is sealed to these sealing portions 14.14. A cap 15.15 connected to the external lead wire 13.13 is attached to these sealing portions 14.14.

Such an arc tube 10 is filled with mercury as a buffer metal, a metal halide as a luminescent metal, and a rare gas such as argon. As a metal norogenide, sodium N
Alkali metal halides such as a and lithium Li are known, but the use of rare earth metal halides such as dysprosium DV, holmium HO, and thulium Tm further improves luminous efficiency and improves color temperature. This has the advantage that the correlated color temperature can be increased to 5000 or more.

Iodine I is used as a halogen to be combined with these metals, and together with the rare earth metals, dysprosium iodide Dyl, holmium iodide Ho I 3
, thulium iodide Tm13, etc.

(Problem to be Solved by the Invention) The metal halide lamp 1 as described above is
In order to reflect the light emitted by the reflector 2 and focus it on the optical system lens 4, conventionally the central axis of the lamp is 0 + 0
1, that is, a line (lamp axis) connecting a pair of opposing electrodes 11a and llb, was attached to the reflector 2 so that it was located on the central axis of the reflector 2, that is, on the optical axis 0□-02.

However, such a metal halide lamp 1
When the lamp axis Or 01 is lit in a horizontal direction (horizontal lighting), the arc generated between the pair of electrodes is curved in an arch shape due to the influence of convection in the discharge space, and the center of light emission is aligned with the reflector 2. There is a tendency for the optical axis to be biased upward from the optical axis 02 02.

Therefore, when used in the image projection apparatus, the brightness of the screen surface varies in the vertical direction, as shown by the broken line B in FIG. 2, and there is a problem that the upper side becomes darker than the lower side.

The present invention was made based on the above circumstances, and an object of the present invention is to provide a flood light source device that can eliminate unevenness in the brightness of reflected light even when the arc curves upward. It is something to do.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a flood light source device using a metal L-ride lamp lit horizontally, in which a substantially midpoint of a pair of electrodes is connected to the light of the reflector. It is characterized in that it is mounted on the reflector and is offset below the axis.

(Function) According to the present invention, the approximate midpoint of the pair of electrodes of the lamp that is lit horizontally is arranged to be offset downward with respect to the optical axis of the reflector, so that the arc curves upward. Also, the center of light emission is exactly aligned with the optical axis of the reflector, and variations in the brightness of reflected light can be reduced.

(Example) Hereinafter, a first example of the present invention will be described using FIG. 1 and FIG. 2 in addition to the previously described drawings.

The overall structure of the projector device is as shown in FIG. 5, and the projection light source device employed in this embodiment is shown in FIG.

The floodlight source device consists of metal halide lamp 1 and reflector 2.
It is made up of.

The metal halide lamp 1 is a 220W type, and each electrode [1a111b] sealed in the arc tube 10 is composed of an electrode shaft 16 and an electrode coil part 17, and the electrode shaft 16 is made of tungsten wire with a wire diameter of 0.8 sv. The electrode coil portion 17 has a wire diameter of 0.8
The electrode coil portion 17 is made of tungsten W (Mar.

The distance between the tips of these electrodes 11a and 11b, that is, the interelectrode distance g, is set to about 4 to 10 mm, and therefore, this metal halide lamp is extremely small and configured to resemble a point light source.

The arc tube 10 is filled with a predetermined amount of mercury as a buffer metal, a metal halide, and a rare gas such as argon.

In the case of this embodiment, the metal halide is a rare earth metal halide, and rare earth metals such as dysprosium DY, holmium Ho, and thulium Tm are encapsulated together with iodine and bromine.

Therefore, in the arc tube 10, dysprosium iodide Dyl, holmium iodide EoI3, thulium iodide Tml3, dysprosium bromide DyBr3, holmium bromide HoBr3, and thulium bromide TmBr3 are sealed.

In this case, the total amount of rare earth metal halogenides enclosed is 2.0 g/cc, and these inclusions have a weight ratio of rare earth metal iodide and rare earth metal bromide of 1:0.5.
It's Nishide.

The metal halide lamp 1 having such a structure is attached to the reflector 2 in the following manner.

That is, a hole 21 is formed in the rear wall of the reflector 2, located on the optical axis 02-〇□, for mounting the lamp, and a cap 15 attached to one sealed end of the lamp 1 is used for mounting the lamp. is inserted into the hole 21 and fixed.

In this case, the lamp l is on the lamp axis 0. -0. is arranged obliquely with respect to the optical axis 02-02 of the reflector 2.

That is, the lamp 1 is mounted around one base 15 attached to the hole 21, that is, one sealed end, and the other base 15, that is, the other sealed end, facing the front side of the reflector 2. The optical axis 02-02 of the reflector 2 is tilted downward with respect to the optical axis 02-02 of the reflector 2. For this reason, the electrode 11b located on the front side is tilted so that the electrode 11b is located on the front side rather than the electrode 11a located on the rear side.

Note that the lamp axis at this time is 0. -0. The inclination angle θ between the optical axis 02-02 and the optical axis 02-02 is set to an angle that corresponds to the amount by which the midpoint P between the electrode 11a and the electrode 11b deviates from the optical axis 02-0□ by a predetermined dimension. The amount of deviation of the predetermined dimension corresponds to the amount by which the center of light emission due to the curvature of the arc deviates from the optical axis 02-0□.

Note that the focal position of the reflector 2 is located between the pair of electrodes 11a and l.
It is set on the optical axis 02 02 located between the electrodes 11a and 1b, and is preferably located on the optical axis 02 02 facing the midpoint P between the electrodes 11a and llb.

In the flood light source device having such a configuration, when the metal halide lamp 1 is lit in a substantially horizontal position, the pair of electrodes 11a
, llb takes on an arch shape under the influence of convection in the discharge space, that is, curves upward, and the center of light emission deviates to the upper side of the lamp axis 0I-0.

However, the lamp axis 0. -0. is installed tilted downward with respect to the optical axis 02-02 of the reflector 2, and the midpoint P between the electrode 11a and the electrode 11b is on the optical axis 02-0.
Since it is arranged to be deviated downward from □, when the light emission center is shifted upward due to the bending of the arc, the light emission center will exactly match or be very close to the optical axis 02 02 of the reflector 2. Become.

Therefore, when viewed from the reflector 2, the light emission center is located on the optical axis 02-02 passing through the focal position, and there is no vertical or horizontal variation in the reflected light.

Therefore, in the image projection apparatus, the brightness of the light projected onto the slurry does not vary vertically, as shown by the solid line A in FIG. 2, and there is no bias in brightness over the entire surface.

In the case of the above embodiment, the lamp axis 01-0 is the optical axis 02.
Although the lamp is tilted relative to -0□, the lamp is mounted so that one base 15 attached to the hole 21 is centered and the other base 15 located on the front side is biased downward. For mounting the lamp, the hole 21 can be formed above the optical axis 0202, so that the reflective surfaces are symmetrical.

However, the present invention is not limited to the first embodiment.

That is, the lamp axis 0. -0. When the optical axis is tilted at 020° with respect to the optical axis, a second embodiment shown in FIG. 3 may be used. In the case of this second embodiment, the rear electrode 1 of the lamp 1 is tilted with the tip of the electrode 11b located on the front side as the center of inclination.
It is tilted so that 1a is biased downward.

Even in this case, since the midpoint P between the electrode 11a and the electrode 11b is deviated downward from the optical axis 0202, if the center of light emission is shifted upward due to the bending of the arc, The light emission center coincides with or comes very close to the optical axis 02-02 or focal point of the reflector 2, and the reflected light no longer varies vertically and horizontally.

Furthermore, the present invention may be configured as a third embodiment shown in FIG.

The third embodiment shows a case in which the lamp 1 is mounted by moving downward in parallel to the reflector 2, and the lamp mounting hole 21 formed on the back wall of the reflector 2 is located along the optical axis 02-02.
It is formed to be biased downward by a dimension m from the lamp 1.
One base 15 of the lamp is inserted into the hole 21 and fixed. And lamp 1 has lamp axis 0. −
0. is arranged so that it is parallel to the optical axis 02-0□ of the reflector 2, and therefore the lamp axis 0. -0. is installed biased downward by a dimension m with respect to the optical axis 02-0□ of the reflector 2.

The amount of deviation m between the lamp axis 010 + and the optical axis 0□02 of the reflector 2 is 0.1g≦m≦ with respect to the distance between the electrodes 11N.
It is set to satisfy the relationship of 0.3g.

Even with this configuration, if the arc generated between the pair of electrodes 11.11 curves upward in an arch shape under the influence of convection in the discharge space, the lamp axis 01-0.
is installed biased downward by a dimension m with respect to the optical axis 0202 of the reflector 2, so that the light emission center coincides with or comes very close to the optical axis 020□ of the reflector 2.

Therefore, since the light emission center is located on the optical axis 0°-02 passing through the focal position, there is no vertical or horizontal variation in the reflected light.

Note that in this case, the lamp axis is 0. -0. The deviation ff1m of the optical axis 02-02 of the reflector 2 satisfies the following relationship with respect to the distance g between the electrodes: 0.1p≦m≦0.3g (1).

m<0. 11, the broken line B in Figure 2 is the same as before.
This causes variations in brightness as shown in , and conversely 0. 'l＜
In the case of m, the brightness on the lower side becomes significantly darker.

Therefore, as long as the above formula (1) is satisfied, there is no problem in practical use.

Furthermore, the present invention provides lamp shaft 0. -0. The electrode may be tilted and moved in parallel with respect to the optical axis 0□-02 of the reflector 2, so that the approximately midpoint of the electrode is deviated below the optical axis of the reflector.

Further, the projecting light source device of the present invention is not limited to the light source of a projector device, but may be applied to a light source of an image projection device such as a movie projector or a magic lantern, or other projecting devices.

[Effects of the Invention] As explained above, according to the present invention, since the midpoint between the electrodes of the lamp that is lit in a substantially horizontal position is deviated downward with respect to the optical axis of the reflector, the arc can be prevented. Even if the reflector is curved upward, the light emission center will coincide with or be close to the optical axis of the reflector, and variations in the brightness of the reflected light will be reduced.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram showing a reflector and metal halide lamp showing a first embodiment of the present invention, Fig. 2 is a characteristic diagram of reflected light, and Fig. 3 is a reflector and metal halide lamp showing a second embodiment of the invention. FIG. 4 is a configuration diagram showing a reflector and metal halide lamp according to a third embodiment of the present invention, FIG. 5 is a principle diagram of a projector device, and FIG. 6 is a configuration diagram showing a conventional reflector and metal halide lamp. FIG. 1...Metal halide lamp, 2...Reflector,
3... Screen, 4... Lens, 5... Liquid crystal display surface, 10... Arc tube, lla, llb... Electrode,
12... Metal foil conductor, 13... External lead wire, 14
... Crushing sealing portion, 15... Mouthpiece, 16... Electrode shaft, 17... Electrode coil. 0, -〇,... Lamp axis, 02-02... Optical axis. Applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 3

Claims (4)

[Claims] (1) Consists of a metal halide lamp in which mercury, a metal halide, and a rare gas are sealed in an arc tube sealed with a pair of electrodes, and a rotating quadratic curved surface that houses the metal halide lamp and reflects the light emitted from the metal halide lamp. In the floodlight source device, the metal halide lamp is lit with a pair of electrodes facing substantially horizontally, and the metal halide lamp has a substantially midpoint between the pair of electrodes below the optical axis of the reflector. A floodlight source device characterized in that it is mounted on a reflector with an offset to the side. (2) By tilting the lamp axis of the metal halide lamp with respect to the optical axis of the reflector, the approximate midpoint of the pair of electrodes is deviated below the optical axis of the reflector. A projection light source device according to claim 1. (3) In the metal halide lamp, the lamp axis is tilted with respect to the optical axis of the reflector with the sealed end facing the rear part of the reflector as the center of inclination, so that approximately the midpoint of the pair of electrodes is aligned with the reflector. 2. The projecting light source device according to claim 2, wherein the projection light source device is deviated below the optical axis of the projection light source device. (4) By moving the lamp axis of the metal halide lamp downward parallel to the optical axis of the reflector, the approximate midpoint of the pair of electrodes is deviated below the optical axis of the reflector. The projection light source device according to claim 1, characterized in that: