JPH09180501A - Light source and image projector using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light source with high convergence efficiency independent of a setting state and provide an image projector using the light source by improving the structure of the light source such as a metal halide lamp. SOLUTION: A light source is constituted of a short arc metal halide lamp 2, a lamp reflector 3 for converging light, a support member 4, and a gravity detecting means 5 for linking and supporting a pair of permanent magnets 11, 12 arranged up and down with a linking means 14. When a weight 13 fixed to the linking means 14 is positioned downward, a pair of permanent magnets 12 on the lower side applies a horizontal transverse magnetic field C to a discharge arc to correct the discharge arc straight. The light source which is uniformly bright even in a reversed state at 180 degrees as in a standing state and an image projector using the light source are realized.

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 such as a metal halide lamp and an image projection device using the same, and more specifically, a permanent magnet is tiltably disposed in the light source device to improve light collecting efficiency. The present invention relates to a light source device and a video projection device using the same.

[0002]

2. Description of the Related Art Conventionally, in a video projection apparatus (a "liquid crystal projector" is taken as an example), the transmitted light of a liquid crystal display panel is projected on a screen to display a video. That is, the liquid crystal projector forms illumination light by a light source such as a metal halide lamp, and drives the respective liquid crystal display panels by using the illumination light with color signals of red (R), green (G), and blue (B), The red (R), green (G), and blue (B) illumination lights split by the splitting means are transmitted to the respective liquid crystal display panels.

After the transmitted lights of these liquid crystal display panels are combined by a combining means, they are projected on a screen by a projection lens to form a color display image. In such an installed state of the liquid crystal projector, the liquid crystal projector is installed upright on a table or the like, or inverted 180 degrees and installed on the ceiling. In addition to the above-mentioned composition formula, the liquid crystal projector
In addition to the single-panel liquid crystal projector that obtains a color image by using a color liquid crystal panel, the front-type liquid crystal projector described above, there is also a rear-type liquid crystal projector that reflects irradiation light by a mirror and irradiates it on the back surface of the screen.

By the way, as shown in FIG. 2B, a light source such as a metal halide lamp is curved in the discharge arc of the light emitting portion due to the influence of temperature rise (the central portion of the discharge arc operates close to the upper wall of the light emitting portion). It is known that this causes a phenomenon), which reduces the light collection efficiency of the concave reflecting mirror.
If such a light source is used in a liquid crystal projector, not only the brightness of the liquid crystal projector is lowered, but also the condensing state of the concave reflecting mirror is changed and a good brightness distribution cannot be obtained on the screen.

In connection with the present invention, a method of controlling the arc shape of a xenon-metal halide lamp by a magnetic field is disclosed in Japanese Patent Application Laid-Open No. 4-312793 as "Acoustic resonance operation method of xenon-metal halide lamp by unidirectional current". However, when this method is applied to a liquid crystal projector, the liquid crystal projector is used upside down (suspended) by 180 degrees as described above, and therefore the magnetic field generating means must be rotated by 180 degrees each time, which is not applicable. There is a problem. The light source device of the present invention is also suitable for application to a lighting device or the like that is used in a movable or rotating manner. However, as an example, a metal halide lamp used as a light source for a liquid crystal projector or the like will be described. To do.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to improve the structure of a light source device such as a metal halide lamp so as not to be affected by the installation posture. It is an object of the present invention to provide a light source device with improved light efficiency and a video projection device using the same.

[0007]

In order to solve the above problems, a light source device of the present invention is a light source device having a light source such as a metal halide lamp and a concave reflecting mirror for condensing light emitted from the light source. A support means disposed in the vicinity of the light source, a gravity detection means pivotally attached to the support means and vertically tiltable by gravity, and integrally formed with the gravity detection means. A magnetic field generating means (permanent magnet) for applying a magnetic field is provided. Then, the gravity detecting means detects the installation state of the light source, and the magnetic field direction of the magnetic field generating means is switched to realize an optimum condensing state that is not affected by the installation state of the light source.

Preferably, the gravity detecting means has a magnetic field generating means formed at the tip thereof, the other end thereof is connected by a connecting means having a weight (weight) attached thereto, and a central portion thereof is axially attached to the supporting means. A link structure composed of a pair of rotors, or magnetic field generating means is formed at both ends of a straight long side, the central part is axially attached to the supporting means, and the weight is provided on the short side branched from the central part. Is preferably one of the attached T-shaped structures.

Further, an image projection apparatus using the light source device of the present invention, the above-mentioned light source device, an image forming means for forming an image using the light source device as a light source, and an image formed by the image forming means are enlarged. And projection means for performing projection.

In the light source device of the present invention, a light source such as a metal halide lamp, a magnetic field generating means for applying a horizontal orthogonal magnetic field axially mounted in the vicinity of the light source via a supporting member, and a magnetic field generating means are integrally formed. The gravity detection means detects the inclination of the light source by gravity, and the gravity detection means switches the magnetic field direction to apply an optimum horizontal orthogonal magnetic field. Therefore, the magnetic field generated by the magnetic field generating means can be applied uniformly without being affected by the installation state of the light source, and the curved state of the discharge arc of a metal halide lamp or the like is corrected linearly to provide an optimum focused state. Can be realized.

In the liquid crystal projection device using the light source device of the present invention, since the above-mentioned light source device is used as the light source, even when the image projection device is upside down by 180 degrees,
Since the magnetic field generated by the magnetic field generating means acts evenly, it is possible to realize a uniform and bright liquid crystal projection device without bias.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a light source device of the present invention and a video projection device using the same will be described below with reference to FIGS.

Embodiment 1 The details of Embodiment 1 of the light source device of the present invention and the image projection apparatus using the same will be described with reference to FIGS. 1 and 2.

First, the structure of the light source device of the present invention will be described with reference to FIG. 1A and 1B are views showing a first embodiment of a light source device of the present invention. FIG. 1A is a sectional view of the light source device of the present invention, FIG. 1B is a rear view of the light source device of the present invention, and FIG. It is a principle view for explaining the operation of the light source device of the present invention.

In FIG. 1, reference numeral 1 indicates a light source device of the present invention. The light source device 1 of the present invention has a rated power of 2 as an example.
50 W, short arc metal halide lamp 2 having an arc length of 3 mm, a concave reflecting mirror (hereinafter simply referred to as “lamp reflector”) 3 that reflects light emitted from the metal halide lamp 2 into a parallel light flux, a supporting member 4, and As a characteristic feature of the present invention, it is roughly constituted by the gravity detecting means 5 and the like arranged on the back surface of the lamp reflector. Incidentally, the metal halide lamp 2 and the lamp reflector 3 are usually used in combination as a unit due to the necessity of adjusting the optical axis.

The metal halide lamp 2 is made of quartz glass and is a conventionally well-known one in which mercury, metal halide and the like are enclosed, and is enclosed in the bulb 6 which is a light emitting portion and the bulb. For example, it is composed of a positive electrode 7 and a negative electrode 8 made of a tritan rod.

The lamp reflector 3 is made of glass, metal, or the like, and has a T-shaped reflective surface on the inner surface of the rotating curved surface.
A vapor deposition film such as iO ₂ -SiO ₂ is formed. The above-described gravity detecting means 5 is arranged on the back surface of the lamp reflector 3 by a predetermined means.

The detailed structure of the gravity detecting means 5 is as follows:
The rotors 9 and 10 are rotatably attached to the support shafts 4a and 4b, and a permanent magnet 11 as magnetic field generating means is arranged at the tip of the rotor 9 on the lamp reflector side so as to face the optical axis B. Has been done. That is, the permanent magnet 11 is arranged so that, for example, the S pole is on the left and the N pole is on the right, as shown in FIG. 7B, and the movable spindle is attached to the other end of the rotor 9 in FIG. 9a is arranged and configured. Similarly, the tip of the rotor 10 on the lamp reflector side is provided with, for example, a permanent magnet 12 arranged so that the N pole comes to the front side of the drawing,
A movable support shaft 10a is arranged at the other end of the rotor 10. The movable support shaft 9a and the movable support shaft 10a are connected by a connecting means 14 to which a weight 13 is attached.

That is, a pair of permanent magnets 11 and a pair of permanent magnets 12 are provided above and below the rear surface of the lamp reflector 3.
Is supported by the connecting means 14 in a link shape, and the connecting means 14
When the weight 13 attached to the lower part is located below, the pair of lower permanent magnets 12 causes the horizontal orthogonal magnetic field C to the discharge arc.
(See FIG. 1B). At this time, the pair of upper permanent magnets 11 is arranged at a position where the magnetic field does not act on the discharge arc. The pair of upper and lower permanent magnets 11 and 12 are arranged at positions where the magnetic fields do not affect each other.

When the light source device 1 of the present invention is inverted by 180 degrees, the weight 13 moves downward (upward in the drawing) due to gravity, and the pair of upper permanent magnets 11 applies a horizontal orthogonal magnetic field C to the discharge arc. The permanent magnets 12 are arranged so as to apply a voltage, and the lower permanent magnets 12 are arranged at positions where they do not act on the discharge arc.

The operation of the light source device of the present invention configured as above will be described.

When the light source device 1 of the present invention is operated by applying a predetermined rated power from a power source (not shown), the positive electrode 7 facing the mercury and the metal halide enclosed in the bulb 6 with each other. A high voltage for starting of about 20 KV is applied via the negative electrode 8 to cause arc discharge and start. Then, after the halogen is excited as separated metal atoms and emits light of a specific spectrum, the light emission is sustained by a well-known halogen cycle that returns to the halogen compound outside the arc A. At this time, the light emitted from the light source and reflected from the lamp reflector 3 has, for example, a light efficiency of 8%.
It is a high-luminance light having a color temperature of 4 Lm / W and a color temperature of 7600K. The sustaining voltage after starting is a low voltage of 100 V or less.

In the light source device 1 of the present invention, since the gravity detecting means 5 is arranged on the rear surface of the lamp reflector 3, the discharge arc and the light emission surrounding the discharge arc which are normally biased to the upper side due to the temperature rise inside the tube 6 are generated. The gas (discharge plasma) receives the Lorentz force F = qVB (where q = charge amount, V = voltage, B = magnetic flux density) and is pushed downward as shown in FIG. As a result, the upper and lower luminance distributions are substantially symmetrical with respect to the electrodes (see FIG. 2A), and the light collection efficiency of the lamp reflector 3 is improved.
At the same time, the brightness is improved as shown in the following experiment. When the temperature of the upper surface of the lamp bulb is measured, it is reduced by about 20 degrees at the 600 temperature level as compared with the case where there is no magnetic field, which can contribute to prolonging the life of the lamp.

Experiment: The conventional light source device and the light source device of the present invention were mounted on a liquid crystal projector, condensed on a 1.3-inch panel size, the brightness thereof was measured by a brightness analyzer, and the absolute value (ratio) thereof was calculated. It was calculated. Results: As shown in Table 1, with respect to the light increase rate in the conventional light source device and the light source device of the present invention, an improvement rate of up to 24% could be obtained. However, the numbers represent luminance (cd / m ² ), and the relative percentages in parentheses. Conditions: Rated power 250 W, 3 mm arc length meta-hara measurement part 1.3 inch panel size condensing part measurement time after startup 15 minutes

[0025]

[Table 1]

The reason why the brightness is improved by providing the magnetic field generating means in the light source is that the discharge arc and the ions surrounding it are generated by applying a predetermined magnetic line of force from the magnetic field generating means to the metal halide lamp.
This is because the light collection efficiency of the lamp reflector is improved due to the substantially vertical distribution. In addition, a discharge lamp such as a metal halide lamp has a high voltage (about 2
0 KV) is applied, but if a strong magnetic field is applied at this time, the lamp may be damaged. Therefore, if necessary, insert a release mechanism (not shown) to release the magnetic field at startup. You can Further, FIG. 2 shows the luminance distribution of the lamp measured from the side of the lamp by a luminance distributor, and does not match the luminance of Table 1.

Next, the structure of a liquid crystal projector using the light source device of the present invention will be described with reference to FIG. FIG. 3 is a side view schematically showing a schematic configuration of a liquid crystal projector using the light source device according to the embodiment of the invention.

In FIG. 3, the structure of the liquid crystal projector using the light source device of the present invention is arranged on the back surface of the metal halide lamp 2, the lamp reflector 3, and the lamp reflector 3 which are the constituent elements of the light source device 1 of the present invention. Optical axis B reflected by gravity detecting means 5 and lamp reflector 3
Etc. Further, as constituent elements of the liquid crystal projector, a condenser lens (condensing lens) 15 for condensing the light reflected by the lamp reflector 3, a liquid crystal display panel 16 as an image forming means for outputting a projected image,
The projection lens 17 and the screen 18 are provided. It should be noted that the image forming means includes a transmission type and a reflection type liquid crystal display panel, a DMD (digital micromirror device) similar thereto, and the like.

The operation of the liquid crystal projector using the light source device of the present invention will be described.

The light emitted from the metal halide lamp 2 of the light source device 1 of the present invention is reflected by the lamp reflector 3 to become a parallel light beam, which advances in the screen direction. Further, it is condensed by the condenser lens 15 and illuminates the liquid crystal display panel 16. The liquid crystal display panel 16 is composed of a transmissive liquid crystal array arranged in a matrix, and displays information such as images and characters in color or monochrome according to an input image signal. The image light transmitted through the liquid crystal display panel 16 is enlarged and projected on the screen 18 by the projection lens 17 to form an image. The screen 18 may be either a reflection type or a transmission type.

When such a liquid crystal projector is used by being rotated by 180 degrees and suspended from the ceiling, the image on the liquid crystal display panel 16 is vertically and horizontally inverted by an image inversion function (not shown) to become a normal image. The weight of the light source device of the present invention is lowered downward by gravity, and the magnetic lines of force applied to the light source are inverted accordingly, and a uniform and bright liquid crystal projector is realized.

Embodiment 2 In this Embodiment 2, instead of the link mechanism in which one weight is used to interlock two permanent magnets in Embodiment 1, the permanent magnet is directly interlocked with the weight. This is an example of such a case, which will be described with reference to FIG. 4A and 4B are views showing a second embodiment of the light source device of the present invention. FIG. 4A is a sectional view of the light source device of the present invention, and FIG. 4B is a rear view of the light source device of the present invention. In the following description, the same parts as those in the first embodiment will be designated by the same reference numerals.

The structure of the light source device of the present invention includes a metal halide lamp 2 forming an arc A between the positive electrode 7 and the negative electrode 8, and a lamp reflector 3 for reflecting the light emitted from the metal halide lamp 2 into a parallel light flux. As a feature of the present invention, it is composed of a gravity detecting means 25 and the like arranged on the back surface of the lamp reflector.

The detailed structure of the gravity detecting means 25 of the present invention is as follows.
A T-shaped rotating body 20 is rotatably mounted on a support shaft 21a of the support member 21 about the support shaft 21a. A weight 23 is disposed on the T-shaped short side of the rotating body 20, and above the T-shaped long side, for example, the S pole is on the left and the N pole is on the right, as shown in FIG. A pair of permanent magnets 11 serving as magnetic field generating means are arranged so as to come, and similarly, a pair of permanent magnets 12 are arranged below the long side of the T-shape so that the N pole comes to the front side of the paper as an example. To be done. That is, the weight 2
3 is located below, a pair of lower permanent magnets 1
2 are arranged so as to apply a horizontal orthogonal magnetic field C (see FIG. 4B) to the discharge arc. The pair of upper permanent magnets 11 and the pair of lower permanent magnets 12 are arranged at positions where magnetic fields do not affect each other.

The operation of the light source device of the present invention having such a configuration will be described.

The light source device of the present invention has a power source (not shown) of approximately 2
When a high voltage for starting of 0 KV was applied, the light source was activated by generation of a discharge arc between the positive electrode 7 and the negative electrode 8,
After that, the light emission is sustained by supplying a sustaining voltage of about 100V.

In the light source device of the present invention, since the gravity detecting means 25 is arranged on the back surface of the lamp reflector 3, the discharge arc and the ions surrounding the discharge arc which are normally biased upward due to the temperature rise inside the tube 6 or the like. However, it is pushed downward by the above-mentioned principle, and becomes a vertically symmetrical distribution with respect to the electrode as shown in FIG. Thereby, the light collection efficiency of the lamp reflector 3 is improved and the brightness is improved. Further, the surface temperature of the lamp bulb is lowered, so that the life of the metal halide lamp is extended.

As is clear from the above embodiment,
It has been proved that by applying a magnetic field to the metal halide lamp by the magnetic field generating means, a maximum brightness improvement effect of 24% can be obtained as compared with the case where no magnetic field is applied. Further, since the direction of application of the magnetic field of the magnetic field generation means is moved by the gravity detection means, the brightness improving effect is not impaired even when the light source device is inverted by 180 degrees.
The configuration and operation of the liquid crystal projector using the light source device of the present invention are the same as those described above, and the description thereof will be omitted because they are redundant.

The present invention is not limited to the above embodiment,
Various embodiments can be adopted. For example, although the gravity detecting means is constituted by the link mechanism or the T-shaped rotating body in the above-described embodiment, any configuration may be used as long as it interlocks with the reversal of the light source. The structure and the number of permanent magnets are not limited. Further, the formation position of the gravity detecting means may be arranged in the central portion other than the rear portion of the lamp reflector or in the front portion. Further, it goes without saying that the present invention can be applied to various forms such as a rear type projector and other light source devices as well as the front type projector.

[0040]

As described above, according to the light source device of the present invention, the back surface of the light source such as a metal halide lamp is
Since the gravity detecting means and the magnetic field generating means interlocked with the gravity detecting means are provided, the magnetic field lines generated by the magnetic field generating means are uniformly applied without being affected by the installation state of the light source. This makes it possible to correct the curved state of the discharge arc of the light source and achieve an optimum focused state regardless of the installation state of the light source, and improve the brightness. Moreover, since the light source device of the present invention has a relatively simple structure, it is possible to construct a high-luminance light source device which is inexpensive and does not require maintenance.

In the liquid crystal projection device using the light source device of the present invention, since the above-mentioned light source device is used as the light source, the magnetic lines of force generated by the magnetic field generating means act uniformly without being affected by the installation state of the liquid crystal projection device. Therefore, even in a situation where the liquid crystal projection device is upside down by 180 degrees, it is possible to realize a uniform and bright liquid crystal projection device.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of a light source device of the present invention, (a) is a cross-sectional view of the light source device of the present invention, (b) is a rear view of the light source device of the present invention, and (c). FIG. 3 is a principle diagram for explaining the operation of the light source device of the present invention.

FIG. 2 is a diagram for explaining the effect of the light source device of the present invention, (a) is a schematic diagram showing the luminance distribution of the discharge arc of the light source device of the present invention, and (b) is a conventional light source device. 3 is a schematic diagram showing the luminance distribution of the discharge arc of FIG.

FIG. 3 is a side view schematically showing a schematic configuration of a liquid crystal projector using the light source device according to the embodiment of the invention.

FIG. 4 is a diagram showing a second embodiment of a light source device of the present invention, (a) is a sectional view of the light source device of the present invention, and (b) is a rear view of the light source device of the present invention.

[Explanation of symbols]

 1 Light Source Device of the Present Invention 2 Metal Halide Lamp 3 Lamp Reflector 4, 21 Supporting Member 5, 25 Gravity Detection Means 6 Tube 7 Positive Electrode 8 Negative Electrode 9, 10 Rotor 11, 12 Permanent Magnet 13, 23 Weight 14 Coupling Means 15 Condenser lens 16 Liquid crystal display panel 17 Projection lens 18 Screen 20 Rotating body

Claims (6)

[Claims] 1. A light source device comprising a light source and a concave reflecting mirror for condensing light emitted from the light source, the supporting means being disposed in the vicinity of the light source, and being pivotally attached to the supporting means. In addition, the gravity detection means is configured to be tiltable by gravity, and the magnetic field generation means that is integrally formed with the gravity detection means and applies a magnetic field to the light source is provided. By switching the magnetic field directions of the light source, an optimal light condensing state is realized without being affected by the installation state of the light source. 2. The light source device according to claim 1, wherein the light source is a metal halide lamp. 3. The gravity detecting means comprises a plurality of rotors whose central portion is axially attached to the supporting means, the magnetic field generating means is formed at the tip of the rotor, and the other end of the rotor is The light source device according to claim 1, wherein the light source device has a link shape in which a weight is connected by a connecting means to which the weight is attached. 4. The gravity detecting means has a T-shape having a central portion pivotally attached to the supporting means, and the magnetic field generating means is formed at both ends of a straight long side of the T-shape. The light source device according to claim 1, wherein a weight is attached to a short side branched from the central portion of the T-shape. 5. The magnetic field generating means is arranged so as to face the optical axis of the light source, and is composed of a permanent magnet for applying a horizontal orthogonal magnetic field to the light source. Light source device. 6. The light source device according to claim 1, an image forming unit that forms an image using the light source device as a light source, and an image formed by the image forming unit is enlarged and projected. An image projection apparatus using a light source device, comprising: