JP3226519B2 - Driving method for high-pressure mercury vapor discharge lamp, driving apparatus for high-pressure mercury vapor discharge lamp, and image 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 method and apparatus for driving a high-pressure mercury vapor discharge lamp having a pair of discharge electrodes inside an arc tube and containing mercury and a rare gas, and such a lamp. And a video projector using the same.

[0002]

2. Description of the Related Art A high-pressure discharge lamp has a feature of high luminance, and is arranged so that a light-emitting portion (arc) is located at a focal point of a reflecting mirror (parabolic mirror or the like). It is used as a light source. When a high-pressure discharge lamp is used as a component of such an optical device, it is necessary to cause light emitted from the lamp to reach a target (projection screen) with as little loss as possible in order to increase the illuminance of the projection screen. For this reason, as a lamp for a light source, it is preferable that the light emitting portion of the lamp is as close as possible to a point light source. More specifically, a so-called short arc lamp having a short light emitting portion is preferable, and a high-pressure mercury vapor discharge lamp is more preferable than a metal halide lamp.

That is, a metal halide lamp emits light at a relatively low arc temperature because the average excitation energy of a single metal encapsulated as a metal halide is low and the metal is relatively low.
The light emitting portion is not likely to be a point light source over a wide range from the center of the arc tube to the tube wall as well as between the electrodes. On the other hand, in a high-pressure mercury vapor discharge lamp, the expansion of the light emitting portion can be suppressed mainly by enclosing mercury having a high average excitation energy, so that a light emitting portion close to a point light source can be easily obtained. An example of such a short arc high pressure mercury vapor discharge lamp is disclosed in, for example, Japanese Patent Application Laid-Open No. 2-148561. This lamp has a mercury vapor pressure of 200 during operation.
When the pressure is equal to or higher than the atmospheric pressure, a continuous radiation component in a visible wavelength region due to mercury molecular emission is generated. This lamp is 5
With 0 W of lamp power, the color rendering is improved in addition to the high brightness, and it is suitable as a light source for a liquid crystal projector.

[0004] Regarding the driving method when the above-mentioned high-pressure mercury vapor discharge lamp is used in a liquid crystal projector or the like, special operating conditions such as instantaneous restart or instantaneous rise of light flux required for a headlight for an automobile are used. Is not required, so it is rarely published especially in literatures, but in general, it is relatively easy to configure a circuit in terms of the response speed of a high-power semiconductor element,
It is driven by an AC having a frequency of about several tens to several hundreds Hz.

In recent liquid crystal projectors, as the screen size increases and the image resolution increases,
There is a need for a lamp with a large lamp power that can increase the illuminance of the projection screen. In order to increase the lamp power, it is conceivable to increase the lamp voltage by increasing the mercury vapor pressure during the lighting operation.However, when it is difficult to increase the mercury vapor pressure due to restrictions on the pressure resistance of the arc tube Means that the lamp current is increased.

[0006]

However, in the case of operating a high-pressure mercury vapor discharge lamp with a large lamp current, the conventional driving method using an alternating current having a frequency of about several tens to several hundreds of Hz requires a projection screen. However, there is a problem that the illuminance tends to change from time to time. Such flicker causes deterioration in image quality when the high-pressure mercury vapor discharge lamp is used in a liquid crystal projector or the like.

The present invention relates to a driving method and a driving apparatus for a high-pressure mercury vapor discharge lamp which does not cause flickering of a projection screen even when the high-pressure mercury vapor discharge lamp is used in a liquid crystal projector or the like even when the lamp is operated with a large lamp current. It is another object of the present invention to provide a video projector using such a driving device.

[0008]

Means for Solving the Problems The inventors of the present invention have investigated the mechanism of causing the flickering of the projection screen to achieve the above object, and found that the movement of the cathode luminescent spot near the tip of the electrode is a cause. I figured it out. Here, the above-mentioned cathode luminescent spot refers to, for example, the luminance distribution of the light emitting portion between the electrodes 11 and 12 as shown in FIG.
In the vicinity of the position where electrons are emitted when each of the electrodes 11 and 12 becomes a cathode, the portion has the highest luminance (reference numerals 11a and 12a in the figure). Hereinafter, a process in which the movement of the cathode luminescent spot occurs will be described.

For example, as shown in FIG.
When a negative voltage is applied to the electrode 12, a certain minute area 11 a near the tip of the electrode 11 becomes hot,
It becomes a cathode luminescent spot where an arc is generated by the action of thermionic emission.
At this time, the minute region 11a is maintained at a higher temperature due to emission of electrons. Next, FIG.
As shown in (2), when the polarity of the applied voltage is reversed, the electrons emitted from the electrode 12 enter a wide range at the tip of the electrode 11. Due to the entry of the electrons, the energy from the electrons is transferred to the electrode 11 and the minute region 1 is transferred.
Not only 1a but also the above wide area is heated.

Here, when the lamp current is relatively small, even if the electrode 11 is heated, the high temperature state of the minute area 11a is maintained as compared with the other areas, so that the polarity of the applied voltage is reversed again. Then, the minute area 11a also becomes a cathode luminescent spot. Therefore, the cathode luminescent spot is located in the minute area 11a.
Once formed, it is difficult to move to other parts and keeps a relatively stable position. However, when the lamp current is large, specifically, as shown in FIG. 2 (c), for example, the electrode 11 is heated over a wide area 11b at the tip end thereof, and the electrode 11 is microscopically instantaneous. If the lamp current is large enough to melt and deform, the minute region 11a is not necessarily required.
Is not necessarily at a higher temperature than the other parts.
(1) A wide range near the tip is a temperature at which a cathode luminescent spot can be formed. Therefore, when the polarity of the applied voltage is reversed again, a minute area 11c different from the minute area 11a may become a cathode luminescent spot, as shown in FIG. 2D. In other words, the position of the cathode luminescent spot tends to frequently move near the tip of the electrode 11 due to the influence of irregularities at the tip of the electrode 11 due to melting deformation and convection generated in the arc tube. The movement of the cathode luminescent spot may occur periodically or suddenly. Such a movement of the cathode luminescent spot can also occur in the electrode 12 as well.

When the cathode luminescent spot moves as described above,
The luminance distribution in the light emitting portion formed between the electrodes 11 and 12 changes. On the other hand, in a liquid crystal projector or the like, since the light emitting section has a finite volume instead of an ideal point light source, light from each section of the light emitting section having a certain extent generally reaches the projection screen and is superimposed. It is configured to be. Therefore, when the luminance distribution of the light emitting unit changes, the illuminance of the projection screen changes. The change in illuminance as described above is a significant problem when using a short arc lamp. Because, in general, in a so-called long arc lamp, the shape and position of the arc are determined by the tube wall of the arc tube, so that the movement of the cathode luminescent spot hardly occurs, and even if it occurs, it does not affect the size of the arc. This is because if the amount of movement of the cathode luminescent spot is small, the influence on the change in illuminance is small.

[0012] The present inventors also considered when the change in illuminance as described above is visually recognized as flicker. As a result, it has been found that, for example, when the change amount of the illuminance exceeds ± 5% of the immediately preceding illuminance and the frequency of occurrence is about 60 times / second or less, it is recognized as flicker and the image quality is reduced.

Based on the above, the present invention has been completed as a result of searching for a method for suppressing the movement of the cathode luminescent spot in order to prevent flickering of the projection screen. That is, claim 1
The invention according to the fourth to fourth aspects is a method for driving a high-pressure mercury vapor discharge lamp having a pair of discharge electrodes provided facing each other in an arc tube and in which at least mercury and a rare gas are sealed. between the electrodes, for example, 2 1 kHz or more, a frequency within the range of 39 kHz, applying an AC voltage having a frequency movement of the cathode spot generated in the vicinity of the tip portion of the discharge electrodes is suppressed Features.

In the high-pressure mercury vapor discharge lamp, when the arc length is d [mm] and the rated power is P [W], the rated power per unit arc length is P / d [W / mm].
The distance between the discharge electrodes and the rated power are set so that P / d ≧ 80 [W / mm].

Since the movement of the cathode luminescent spot is suppressed by the driving method of applying an AC voltage having such a frequency to the lamp, for example, when a high-pressure mercury vapor discharge lamp is used in a liquid crystal projector or the like, the cathode luminescent spot is not affected. It is possible to prevent the projection screen from flickering due to the movement. Claims
The inventions of 5 to 11 are characterized in that the arc tube is provided with the opposing 1
A driving device for a high-pressure mercury vapor discharge lamp that has a pair of discharge electrodes and is lit by applying an AC voltage between the discharge electrodes of the high-pressure mercury vapor discharge lamp in which mercury and a rare gas are sealed, If the frequency of the AC voltage is 2
A frequency in the range of 1 kHz or more and 39 kHz or less, which is a frequency at which the movement of the cathode luminescent spot generated near the tip of the discharge electrode is suppressed, specifically, for example, near the tip of the discharge electrode When the arc image is projected on a predetermined projection surface, the frequency is such that the change in illuminance on the projection surface is ± 5% or less.

In the high-pressure mercury vapor discharge lamp, when the arc length is d [mm] and the rated power is P [W], the rated power per unit arc length is P / d [W / mm].
The distance between the discharge electrodes and the rated power are set so that P / d ≧ 80 [W / mm], or the distance between the discharge electrodes is 3 [m
m] or less, or the temperature near the tip of the discharge electrode during lighting is 3000 K or more.

By using a driving device that applies an AC voltage having such a frequency to the lamp, the movement of the cathode luminescent spot is suppressed. For example, when a high-pressure mercury vapor discharge lamp is used in a liquid crystal projector or the like, the cathode It is possible to prevent the projection screen from flickering due to the movement of the bright spot.
The invention according to claims 12 and 13 is the driving device for a high-pressure mercury vapor discharge lamp according to claims 5 to 8 , further comprising frequency adjusting means for adjusting the frequency of the AC voltage, and further comprising the discharge electrode. Detecting means for detecting the luminance near the tip of the discharge electrode, and the frequency adjusting means changes the frequency of the AC voltage in the vicinity of the tip of the discharge electrode in accordance with the detection result of the detecting means. It is characterized in that it is configured to adjust to a frequency at which point movement is suppressed.

This makes it possible to reliably suppress the movement of the cathode luminescent spot and prevent flickering of the projection screen even when the characteristics of the lamp vary or change over time. A fourteenth aspect of the present invention is an image projector, comprising: a high-pressure mercury vapor discharge lamp having a pair of discharge electrodes provided to face each other in an arc tube, wherein at least mercury and a rare gas are sealed. And a driving device that applies an AC voltage between the discharge electrodes to turn on the high-pressure mercury vapor discharge lamp, and projects an image on a projection screen using light emitted from the high-pressure mercury vapor discharge lamp as light source light. A frequency of the AC voltage applied by the driving device to the high-pressure mercury vapor discharge lamp is a frequency at which movement of a cathode luminescent spot generated near a tip of the discharge electrode is suppressed. It is characterized by.

Thus, the movement of the cathode luminescent spot is suppressed,
Since flickering of the projection screen is prevented, high image quality can be obtained.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, an image projector provided with a high-pressure mercury vapor discharge lamp will be described. This image projector is provided with a lamp unit 23 in which a high-pressure mercury vapor discharge lamp 21 and a parabolic mirror 22 are combined as shown in FIG. The high-pressure mercury vapor discharge lamp 21 includes a driving device 2 having a function as a ballast.
4, an AC voltage having a predetermined frequency described later is applied. On the emission light side of the lamp unit 23, a UV filter 25 for compensating the color temperature of light emitted from the high-pressure mercury vapor discharge lamp 21 and a folding mirror 26 are provided. The light emitted from the turning mirror 26 is separated by the dichroic mirrors 27 and 28 into monochromatic light of the three primary colors of RGB, and enters the liquid crystal panels 32-34 via the turning mirrors 29-31.
The luminance is modulated. The light of each color whose luminance has been modulated is synthesized by the dichroic prism 35, and is projected on the screen 37 by the projection lens 36. The liquid crystal panels 32-34
Instead, a luminance modulation element such as a DMD may be used.

More specifically, as shown in FIG. 4, the high-pressure mercury vapor discharge lamp 21 constituting the lamp unit 23 includes a pair of coil-shaped or rod-shaped discharge electrodes 21b made of tungsten in an arc tube 21a. , 21c, and mercury and a rare gas (not shown) are sealed therein. Note that a halogen gas, a nonmetal halide such as methyl bromide, or a metal halide such as mercury bromide may be further sealed as the sealing substance. This high-pressure mercury vapor discharge lamp 21
A light emitting portion 21d by an arc formed between the discharge electrodes 21b and 21c is provided so as to be located at the focal point of the parabolic mirror 22, and most of the emitted light is substantially parallel to the optical axis of the parabolic mirror 22. The light is emitted as a light. More specifically, if the light emitting unit 21d is an ideal point light source, the light emitted from the parabolic mirror 22 is perfectly parallel light. However, in practice, the light emitting unit 21d has a certain size (finite volume). ), The light emitted from near the focal point of the parabolic mirror 22 becomes light slightly deviated from the parallel light. Therefore,
The projection optical system such as the projection lens 36 is designed to project as much light as possible from each unit in the light emitting unit 21d onto the screen 37, even if the light deviates from the parallel light. Next, the relationship between the movement of the cathode luminescent spot and the fluctuation of the screen illuminance in the high-pressure mercury vapor discharge lamp 21 and the frequency of the power supply for driving the high-pressure mercury vapor discharge lamp 21 will be described.

In order to measure the change in screen illuminance,
An apparatus as shown in FIG. 5 was manufactured. That is, using the imaging lens 41, the illuminometer 42 is placed at a position where the discharge electrodes 21b, 21c and the light emitting portion 21d of the high-pressure mercury vapor discharge lamp 21 connect the images 21b ', 21c', 21d 'enlarged 20 times. Placed. The high-pressure mercury vapor discharge lamp 21 has a rated power of 150 W and an arc length of 1.5 mm.
(Rated power / arc length = 100 W / mm) and the diameter of the discharge electrodes 21b and 21c was 1.2 mm. The illuminometer 42 used had a light receiving portion with a diameter of 10 mm (substantially the size of the image of the cathode luminescent spot). As a result, when the cathode luminescent spot moves, the indicated value of the illuminometer 42 changes, and the movement of the cathode luminescent spot can be measured by the change in the indicated value. In this case, the illuminance at the position of the illuminometer 42 is actually measured,
This is substantially the same as detecting the luminance near the distal ends of the discharge electrodes 21b and 21c.

The high pressure mercury vapor discharge lamp 21
When a rectangular wave voltage having a frequency of 270 Hz was applied to the device to light it, and the illuminance was measured, the result was as shown in FIG.
That is, approximately 40 times of a state (illuminance change) that greatly changes with respect to the immediately preceding illuminance (counts the cases where the illuminance increases and decreases, respectively) in about 30 minutes. These are all due to the movement of the cathode luminescent spot.

On the other hand, a sine wave voltage having a frequency of 29 kHz is applied to the high-pressure mercury vapor discharge lamp 21 to light it,
When the illuminance was measured, as shown in FIG. 7, the change in the illuminance as described above, that is, the shift of the cathode luminescent spot hardly occurred.

In the image projector shown in FIG. 3, a similar voltage (270H) is applied to the high-pressure mercury vapor discharge lamp 21.
When a rectangular wave voltage of z or a sine wave voltage of 29 kHz) was applied and the screen 37 was observed, clear flicker was perceived only in the former case. Furthermore, by applying voltages of various frequencies and waveforms, the relationship between the degree and frequency of the illuminance change and the perception of the presence or absence of flicker on the projection screen was examined. As a result, for example, when the change amount of the illuminance exceeds ± 5% of the immediately preceding illuminance and the frequency of occurrence is less than about 60 times / second, it is easily recognized as flicker, and the image quality is significantly reduced. Was.

Furthermore, arc lengths of 1.7 mm and 1.8 mm (rated power / arc length ≒ 88, 83 W / m) with the same specifications as the lamp used for measuring the change in illuminance described above.
With respect to the lamp m), the same measurement was performed for 3 minutes by applying sine wave voltages of various power supply frequencies. The results are shown below (Table 1).

[0027]

[Table 1] In the same table, the mark ○ indicates that the cathode luminescent spot did not move (the change in the illuminance was ± 5% or less, or the frequency of occurrence was 60 times / second or more), and the mark × indicates the cathodoluminescence. This indicates that a point shift has occurred (the amount of change in illuminance exceeded ± 5%, and the frequency of occurrence was less than 60 times / second). From the table, the power frequency is 2 1 kHz or more, within the range of 39 kHz,
It was found that there was a frequency band in which the movement of the cathode luminescent spot did not occur (or was small). At a power supply frequency of about 30 kHz, no movement of the cathode luminescent spot occurred in any of the arc length lamps. Therefore, by selecting one of the frequencies in the above band, the movement of the cathode luminescent spot can be suppressed, and the flickering of the projection screen can be prevented. In particular, when the temperature of the tips of the discharge electrodes 21b and 21c is about 3000K or more, the movement of the cathode luminescent spot is apt to occur, so that the selection of the power supply frequency has a great effect of preventing flicker.

A similar result was obtained when a rectangular wave voltage was applied instead of a sine wave voltage. However, applying a sine wave voltage more reliably suppresses the movement of the cathode luminescent spot. I was able to. Further, in the above example, an example in which the threshold value of the change amount of the illuminance is set to ± 5% is shown. Any frequency may be selected as long as it does not substantially matter the degree of flicker of the projection screen. The specifications of the high-pressure mercury vapor discharge lamp are not limited to those described above, and a similar effect can be obtained by appropriately selecting the power supply frequency. In particular, rated power / arc length ≧ 80 W / m
m, or when the arc length (distance between electrodes) was 3 mm or less, the effect of preventing flickering of the projection screen was surely obtained. Another example of the video projector will be described. As shown in FIG. 8, this video projector is different from the video projector shown in FIG. 3 in that a detection unit 51 for detecting the movement of the cathode luminescent spot is provided. The difference is that a frequency control unit 52 that controls (adjusts) the frequency of the voltage to be applied to the power supply is provided. The detection unit 51 includes an imaging lens 41 and an illuminometer 42 as in FIG. 5, and measures illuminance due to light leaking through the reflecting surface of the parabolic mirror 22. The frequency control unit 52 controls the frequency of the voltage output from the driving device 24 according to the measurement result of the detection unit 51 so that the movement of the bright spot is suppressed. More specifically, for example, when the lighting of the lamp is started or when a change in illuminance is detected, the frequency is sequentially changed within a range of 20 to 42 kHz, and a frequency having no or little change in illuminance is searched. It has become. With such a configuration, even if the characteristics of the high-pressure mercury vapor discharge lamp 21 vary or change over time,
It is possible to reliably suppress the movement of the cathode luminescent spot and prevent flickering of the projection screen.

The illuminometer 42 is not limited to one that measures illuminance by light leaking through the reflecting surface of the parabolic mirror 22 as described above. You may make it measure by the emitted light. Further, the illuminance on the screen 37 may be detected.
Further, the detection unit 51 is not necessarily provided as described above, and the frequency of the voltage output from the driving device 24 may be manually adjusted.

[0030]

The present invention is embodied in the form described above and has the following effects.

That is, the movement of the cathode luminescent spot is suppressed by applying an AC voltage between the pair of discharge electrodes at a frequency at which the movement of the cathode luminescent spot generated near the tip of the discharge electrode is suppressed. In addition, it is possible to prevent flickering of the projection screen, and to obtain a projection image of high image quality.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a luminance distribution of a light emitting portion between electrodes.

FIG. 2 is an explanatory diagram showing a mechanism of moving a cathode luminescent spot.

FIG. 3 is an explanatory diagram illustrating a configuration of a video projector according to an embodiment.

FIG. 4 is a cross-sectional view illustrating a configuration of a high-pressure mercury vapor discharge lamp according to an embodiment.

FIG. 5 is an explanatory diagram showing a configuration of an apparatus for measuring a change in illuminance due to movement of a bright spot.

FIG. 6 is a graph showing a change in illuminance when a bright spot moves.

FIG. 7 is a graph showing a change in illuminance when movement of a bright spot is suppressed.

FIG. 8 is an explanatory diagram showing a configuration of another video projector according to the embodiment.

[Explanation of symbols]

 11, 12 electrode 11a minute area 11a, 11c, 12a minute area (cathode luminescent spot) 11b area 12 electrode 21 high-pressure mercury vapor discharge lamp 21a arc tube 21b, 21c discharge electrode 21d light emitting section 21b ', 21c', 21d 'image 22 Parabolic mirror 23 Lamp unit 24 Driver 25 UV filter 26 Folding mirror 27, 28 Dichroic mirror 29-31 Folding mirror 32-34 Liquid crystal panel 35 Dichroic prism 36 Projection lens 37 Screen 41 Imaging lens 42 Illuminance meter 51 Detector 52 Frequency control unit

Continuing on the front page (72) Inventor Takeharu Tsutsumi 1006 Kadoma, Kadoma, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. 56) References JP-A-5-166592 (JP, A) JP-A-11-283575 (JP, A) JP-A-10-112289 (JP, A) JP-A-9-260072 (JP, A) Hei 7-14689 (JP, A) JP 10-92378 (JP, A) JP 11-86796 (JP, A) (58) Fields studied (Int. Cl. ⁷ , DB name) H05B 41 / 24-41/29 G03B 21/14 H01J 61/50-65/08

Claims (14)

(57) [Claims] 1. A method for driving a high-pressure mercury vapor discharge lamp having a pair of discharge electrodes provided in an arc tube and opposed to each other, wherein at least mercury and a rare gas are sealed, A method for driving a high-pressure mercury vapor discharge lamp, wherein an alternating voltage having a frequency at which movement of a cathode luminescent spot generated near the tip of the discharge electrode is suppressed is applied. 2. A method for driving a high-pressure mercury vapor discharge lamp of claim 1, the frequency of the AC voltage applied between the discharge electrodes 2 1
A method for driving a high-pressure mercury vapor discharge lamp, wherein the frequency is in the range of not less than kHz and not more than 39 kHz. 3. A pair of opposing pairs provided in an arc tube.
Has a discharge electrode, at least mercury and a rare gas are sealed
A method for driving a high-pressure mercury vapor discharge lamp,
The frequency of the AC voltage applied between the discharge electrodes is 21 kHz
at a frequency in the range from z to 39 kHz,
The mercury vapor discharge lamp has an arc length of d [mm]
When the force is P [W], the rating per unit arc length
Power P / d [W / mm] becomes P / d ≧ 80 [W / mm]
So that the distance between the discharge electrodes and the rated power
High-pressure mercury vapor discharge lamp characterized in that
How to drive the pump. 4. The method for driving a high-pressure mercury vapor discharge lamp according to claim 1, wherein the high-pressure mercury vapor discharge lamp has an arc length d [mm] and a rated power P [W].
The rated power P / d [W / mm] per unit arc length is P
A method for driving a high-pressure mercury vapor discharge lamp, wherein the distance between the discharge electrodes and the rated power are set so that / d ≧ 80 [W / mm]. 5. A high-pressure mercury vapor discharge lamp having a pair of discharge electrodes opposed to each other in an arc tube, wherein at least mercury and a rare gas are sealed, an AC voltage is applied between the discharge electrodes. A driving device for a high-pressure mercury vapor discharge lamp to be turned on and lighted, wherein the frequency of the AC voltage is a frequency at which the movement of a cathode luminescent spot generated near the tip of the discharge electrode is suppressed. Drive device for high-pressure mercury vapor discharge lamp. 6. A driving device of a high-pressure mercury vapor discharge lamp of claim 5, the frequency of the AC voltage applied between the discharge electrodes, 2 1 kHz or more, at a frequency within the following ranges 39 kHz A driving device for a high-pressure mercury vapor discharge lamp, comprising: 7. A pair of opposing pairs provided in an arc tube.
Has a discharge electrode, at least mercury and a rare gas are sealed
A method for driving a high-pressure mercury vapor discharge lamp,
The frequency of the AC voltage applied between the discharge electrodes is 21 kHz
at a frequency in the range from z to 39 kHz,
The mercury vapor discharge lamp has an arc length of d [mm]
When the force is P [W], the rating per unit arc length
Power P / d [W / mm] becomes P / d ≧ 80 [W / mm]
So that the distance between the discharge electrodes and the rated power
High-pressure mercury vapor discharge lamp characterized in that
Drive of the pump. 8. The driving device for a high-pressure mercury vapor discharge lamp according to claim 5, wherein the high-pressure mercury vapor discharge lamp has an arc length d [mm] and a rated power P [W].
The rated power P / d [W / mm] per unit arc length is P
A driving device for a high-pressure mercury vapor discharge lamp, wherein the distance between the discharge electrodes and the rated power are set so that / d ≧ 80 [W / mm]. 9. The driving apparatus for a high-pressure mercury vapor discharge lamp according to claim 5 , wherein the frequency of the AC voltage is determined when an arc image near the tip of the discharge electrode is projected on a predetermined projection surface. The driving device for a high-pressure mercury vapor discharge lamp, wherein the frequency at which the change in illuminance of the projection surface is ± 5% or less. 10. The driving device for a high-pressure mercury vapor discharge lamp according to claim 5 , wherein a distance between the discharge electrodes of the high-pressure mercury vapor discharge lamp is 3 mm or less. Drive device for high-pressure mercury vapor discharge lamp. 11. The driving apparatus for a high-pressure mercury vapor discharge lamp according to claim 5, wherein the high-pressure mercury vapor discharge lamp has a temperature near the tip of the discharge electrode of 300 when lit.
A driving device for a high-pressure mercury vapor discharge lamp, which is at least 0K. 12. The driving apparatus for a high-pressure mercury vapor discharge lamp according to claim 5 , further comprising frequency adjusting means for adjusting the frequency of the AC voltage. . 13. The driving device for a high-pressure mercury vapor discharge lamp according to claim 12 , further comprising detecting means for detecting a luminance near a tip portion of the discharge electrode, wherein the frequency adjusting means includes a detecting means. The high-pressure mercury vapor is configured to adjust the frequency of the AC voltage to a frequency at which the movement of the cathode luminescent spot generated near the tip of the discharge electrode is suppressed according to the detection result. Driving device for discharge lamp. 14. A high-pressure mercury vapor discharge lamp having a pair of discharge electrodes provided facing each other in an arc tube and containing at least mercury and a rare gas, and an AC voltage applied between the discharge electrodes. A driving device for applying light to the high-pressure mercury vapor discharge lamp to apply light, and using the light emitted from the high-pressure mercury vapor discharge lamp as light source light to project an image on a projection screen, wherein the driving device Wherein the frequency of the AC voltage applied to the high-pressure mercury vapor discharge lamp is a frequency at which movement of a cathode luminescent spot generated near the tip of the discharge electrode is suppressed.