JP2009266406A - Lighting device for discharge lamp, and projection image display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device capable of improving the time until video image projection by shortening operation and processing of a projection image display device by performing lighting determination of a discharge lamp at an earlier timing, and to provide the projection image display device. <P>SOLUTION: When a drive signal b is sent from a lighting control part 3 to an inverter circuit part 1, if the electrodes in the discharge lamp 6 are insulation-broken in a time period t1 by a high voltage generation circuit part 2, a discharge path is formed in the discharge lamp 6 and a voltage detection part 4 detects a voltage V2 which is lowered by a prescribed amount after the insulation breakdown between the electrodes, and by the voltage detection signal a, the lighting control part 3 carries out lighting determination. When it is detected that the discharge lamp is lighted normally, a lighting determination signal c to start an operation of a video image signal processing part 8 is sent to a set microcomputer 7. Then, the set microcomputer 7 sends a signal d for starting the video image signal processing to the video image signal processing part 8, and input of the video image signal is started to carry out image projection. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device for lighting a discharge lamp such as a high pressure mercury lamp, and a projection type image display device using these discharge lamps.

  Projection type image display devices (for example, projectors) are often used mainly in educational institutions such as schools and corporate meeting rooms, and are now easily carried by miniaturization of projection type image display devices. The environment in which it is used is expanding rapidly.

  In such a projection-type image display device, a discharge lamp such as a high-pressure mercury lamp is used for image projection, and the discharge lamp lighting device is required to stably light the discharge lamp.

  Generally, a discharge lamp drive circuit starts a discharge between electrodes and generates a high voltage until stable operation is started, and supplies a desired stable power to the discharge lamp at a relatively low pressure after the discharge is stabilized. It has the function to do.

  Usually, the switching is realized by switching the drive frequency of the four switch elements. A high voltage is generated at a high voltage generation circuit at a high frequency until stable operation is performed, and the frequency is set low after stable operation. The action of the voltage generation circuit is invalidated.

As described in Patent Document 1, in order to prevent malfunction due to noise during operation of the high voltage generation circuit of the control unit including the drive circuit in the discharge lamp lighting device, noise is removed by signal processing, There has been disclosed a discharge lamp lighting device that performs lighting lamp lighting determination and performs discharge lamp lighting control with high accuracy.
Japanese Patent Application Laid-Open No. 2002-175992

  However, the above-described conventional discharge lamp lighting device has a high voltage generation circuit in order to prevent malfunction due to noise during operation of the high voltage generation circuit when data communication of the video signal processing unit in the projection type image display device is started. The circuit current of the drive circuit is detected after the stable operation where the action is almost eliminated, and the lighting is determined based on the current level.

  In this case, there is a problem that the operation and processing of the projection-type image display device are limited until the lighting determination has no effect of the high voltage generation circuit and a more stable current can be detected.

  The present invention solves the above-described problem, and by performing the lighting lamp lighting determination at an earlier timing, the operation and processing such as the start of data communication of the projection type image display device is accelerated, and the time until video projection is performed. An object of the present invention is to provide a discharge lamp lighting device and a projection type image display device capable of improving the above.

In order to solve the above problems, the discharge lamp lighting device of the present invention is:
An inverter circuit unit for generating an AC voltage from a DC voltage by opening and closing the switch element in accordance with a rectangular wave-shaped drive control signal, and supplying an AC current to the discharge lamp;
A high voltage generating circuit for generating a high voltage necessary for the discharge lamp to start lighting; and
A voltage detection unit for detecting a voltage generated in the high voltage generation circuit unit;
Based on a detection signal from the voltage detection unit that sends a drive signal to the inverter circuit unit to control a resonance voltage of a resonance circuit included in the high voltage generation circuit unit and indicates that the voltage has decreased by a predetermined amount. A lighting control unit that outputs a lighting determination signal of the discharge lamp;
Consists of

The projection type image display device of the present invention is
A discharge lamp lit by high voltage,
An inverter circuit unit for generating an AC voltage from a DC voltage by opening and closing the switch element in accordance with a rectangular wave-shaped drive control signal, and supplying an AC current to the discharge lamp;
A high voltage generating circuit for generating a high voltage necessary for the discharge lamp to start lighting; and
A voltage detection unit for detecting a voltage generated in the high voltage generation circuit unit;
Based on a detection signal from the voltage detection unit that sends a drive signal to the inverter circuit unit to control a resonance voltage of a resonance circuit included in the high voltage generation circuit unit and indicates that the voltage has decreased by a predetermined amount. A lighting control unit that outputs a lighting determination signal of the discharge lamp;
A device control unit that performs transmission and reception with the lighting control unit;
A video signal processing unit for controlling video signal input and output,
The device control unit controls the video signal processing unit based on a lighting determination signal from the lighting control unit.

  In the discharge lamp lighting device, the period in which noise is mainly generated is a period in which the high voltage generation circuit unit is operating. Therefore, when the discharge between the electrodes of the discharge lamp starts, the high voltage generation circuit unit does not work. The voltage of the high voltage generation circuit unit is detected, and when the voltage has decreased by a predetermined amount, data communication of the signal processing unit is started at an earlier timing, and the operation and processing of the projection type image display device are performed. It has an effect of accelerating.

  In addition, the lamp may be extinguished after the start of discharge, and the current flowing through the discharge lamp is also detected in order to detect this, thereby ensuring lighting determination.

  According to the present invention, it is possible to accelerate the operation and processing of the projection-type image display device by improving the lighting lamp lighting timing at an earlier timing, and to improve the time until video projection. Convenience can be given to the user.

  Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1)
FIG. 1 is a block diagram showing a configuration of a projection type image display apparatus having a discharge lamp lighting device according to Embodiment 1 of the present invention.

  In FIG. 1, the projection type image display apparatus includes an inverter circuit unit 1 that applies an AC voltage to a discharge lamp 6 and causes an AC current to flow by a full-bridge circuit type DC / AC commutator including four switch elements. A high voltage generation circuit that is a circuit that generates a high voltage only at the start of lighting, including a resonance circuit and a high voltage pulse superposition circuit, for the purpose of causing discharge between the electrodes of the discharge lamp 6 in order to light the electric lamp 6 From the above, the lighting control unit 3 that controls the high voltage generation circuit unit 2 by sending a drive signal to the unit 2 and the inverter circuit unit 1 and determines lighting of the discharge lamp 6 by voltage detection of the voltage detection unit 4 A discharge lamp lighting device 5 configured, a discharge lamp 6 that is a high-pressure mercury lamp lamp, a video signal processing unit 8 that controls input / output of a video signal, transmission / reception with the video signal processing unit 8, and a discharge lamp lighting device 5 Lighting start and consists of a set microcomputer 7 for transmitting and receiving a stop signal.

  Further, a is a detection signal from the voltage detection unit 4, b is a drive signal from the lighting control unit 3 to the inverter circuit unit 1, c is a lighting discrimination signal sent from the lighting control unit 3 to the set microcomputer 7, and d is a set microcomputer. 7 shows a signal for starting video signal processing sent from 7 to the video signal processing unit 8.

  The operation of the projection type image display apparatus configured as described above will be described below.

  The voltage between the electrodes in the discharge lamp 6 is the discharge lamp voltage, the flowing current is the discharge lamp current, and a graph of the discharge lamp voltage and the discharge lamp current versus time is shown in FIG.

  In the discharge lamp lighting device 5, when the driving signal b is sent from the lighting control unit 3 to the inverter circuit unit 1, the inverter circuit unit 1 applies an AC voltage to the discharge lamp 6, and the high voltage generation circuit unit 2 is connected to the discharge lamp 6. When a high voltage V1 necessary for dielectric breakdown between the electrodes is generated and the dielectric breakdown occurs between the electrodes at time t1, a discharge path in the discharge lamp 6 is formed.

  As a result, when a current flows through the discharge lamp 6, the voltage in the discharge lamp 6 decreases to the voltage V2.

  Thereafter, by supplying a constant current I1 necessary for maintaining the discharge, the temperature in the discharge lamp 6 is preheated for a period of t1-t2, and the discharge is stabilized. At this time, the voltage further decreases to the voltage V3.

  The period up to time t2 is the starting period of the discharge lamp 6.

  After time t2 when the discharge is stabilized, the discharge lamp lighting device 5 shifts from constant current control to constant power control in which a current I2 corresponding to the voltage V3 is supplied in order to supply desired power to the discharge lamp 6.

  In the conventional lighting discrimination method, a signal d for starting the video signal processing operation is sent from the set microcomputer 7 to the video signal processing unit 8 by detecting the current I2 whose discharge after the start-up period is sufficiently stable. Since the video signal processing unit 8 starts to input the video signal, the video projection of the projection type image display apparatus requires time t2.

  In the present embodiment, as shown in FIG. 1, when a drive signal b is sent from the lighting control unit 3 to the inverter circuit unit 1, the high voltage generation circuit unit 2 causes the electrodes in the discharge lamp 6 to be connected at time t <b> 1. When the dielectric breakdown occurs, a discharge path in the discharge lamp 6 is formed, and the voltage detection unit 4 detects the voltage V2 that has decreased by a predetermined amount after the dielectric breakdown between the electrodes, and the lighting control unit 3 uses the voltage detection signal a. To determine lighting.

  When it is determined that the lighting is normal, a lighting determination signal c for starting the operation of the video signal processing unit 8 is sent to the set microcomputer 7, and a signal d for starting the video signal processing is sent from the set microcomputer 7 to the video signal processing unit. 8, input of the video signal is started, and video projection is performed.

  In the discharge lamp lighting device 5, the period in which noise is mainly generated is a period in which the high voltage generation circuit unit 2 is operating. Therefore, when discharge between the electrodes of the discharge lamp 6 starts, the high voltage generation circuit unit 2. No longer works.

  As can be seen from FIG. 2, at the time t3 when the voltage V2 is detected, the discharge lamp current has not yet reached the constant current I1, but since the voltage has dropped, the occurrence of noise is small and even if a video signal is input. There is almost no influence by noise.

  In this way, the time for starting the input of the video signal is advanced from t2 to t3, whereby the time until video projection of the projection type image display apparatus can be shortened.

(Embodiment 2)
FIG. 3 is a block diagram showing a configuration of a projection type image display apparatus having a discharge lamp lighting apparatus according to Embodiment 2 of the present invention. 3, the same components as those in FIG. 1 of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  3 differs from FIG. 1 in that a current detection unit 9 is provided between the inverter circuit unit 1 and the high voltage generation circuit unit 2 of the discharge lamp lighting device 5, and the lighting control unit 3 determines lighting by the current detection signal e. It is a point that I tried to do.

  In FIG. 2 of the first embodiment, after detecting the voltage V2 after dielectric breakdown at time t1, video projection is performed by lighting determination, but in the period from time t1 to t2, which is the starting period, the discharge lamp 6 Because it may not be able to maintain a stable discharge within the lamp, it may lose light (turn off), so that current flows when it is lit and current does not flow when it is not lit. By confirming that the current flows through the discharge lamp 6, it is possible to ensure lighting determination.

  The operation of the discharge lamp lighting device and the projection type image display device in the present embodiment will be described with reference to the flowchart shown in FIG.

  First, when the drive signal b is sent from the lighting control unit 3 to the inverter circuit unit 1, the lighting control unit 3 starts lighting the discharge lamp 6 by the high voltage generation circuit unit 2 (step 1). A high voltage is generated between the electrodes (step 2), and the voltage detector 4 detects the voltage (step 3).

  Therefore, if a high voltage is detected, it is determined as abnormal, the high voltage generation circuit unit 2 continues to generate a high voltage, the discharge lamp 6 is dielectrically broken, and a normal voltage is detected when the voltage detection unit 4 detects a low voltage. It discriminate | determines (step 4), the operation | movement start of the video signal processing part 8 is performed (step 5), and a video projection is performed (step 6).

  On the other hand, the current detection unit 9 detects that a current is flowing (step 7), and the lighting control unit 3 outputs a lighting determination signal c to the set microcomputer 7 based on the current detection signal e (step 8). The set microcomputer 7 determines the lighting determination and continues the video projection (step 9).

  When the current detection unit 9 detects that no current flows through the discharge lamp 6 (step 7), the lighting control unit 3 determines that there is an abnormality based on the current detection signal e (step 8).

  The lighting determination signal c is output to the set microcomputer 7, and the set microcomputer 7 sends a signal instructing the video signal processing stop to the video signal processing unit 8 to stop the operation (step 10).

  Thereafter, the lighting control unit 3 performs a relighting operation to start lighting the discharge lamp lighting device 5.

  Thus, by performing current detection together, it can be confirmed that the current flows through the discharge lamp 6 and the lighting determination can be ensured, and there is no possibility of the lamp being extinguished (turned off).

  Thereby, the lighting determination timing can be advanced and the lighting determination can be performed reliably.

  The projection type image display device of the present invention is useful for a projection type image display device such as a projector because the time to determine the lighting of the discharge lamp can be made earlier so that the time until video projection can be shortened.

1 is a block diagram showing a configuration of a projection type image display apparatus having a discharge lamp lighting device according to Embodiment 1 of the present invention. The figure which shows the discharge lamp voltage of the projection type image display apparatus in Embodiment 1 of this invention, discharge lamp current versus time. The block diagram which shows the structure of the projection type image display apparatus which has a discharge lamp lighting device in Embodiment 2 of this invention. Flowchart showing the operation of the projection type image display apparatus in the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inverter circuit part 2 High voltage generation circuit part 3 Lighting control part 4 Voltage detection part 5 Discharge lamp lighting device 6 Discharge lamp 7 Set microcomputer 8 Video signal processing part 9 Current detection part a Voltage detection signal b Inverter circuit drive signal c Lighting discrimination Signal d Signal to start video signal processing e Current detection signal

Claims (5)

A discharge lamp lighting device for lighting a discharge lamp of a projection type image display device,
An inverter circuit unit for generating an AC voltage from a DC voltage by opening and closing the switch element in accordance with a rectangular wave-shaped drive control signal, and supplying an AC current to the discharge lamp;
A high voltage generating circuit for generating a high voltage necessary for the discharge lamp to start lighting; and
A voltage detection unit for detecting a voltage generated in the high voltage generation circuit unit;
Based on a detection signal from the voltage detection unit that sends a drive signal to the inverter circuit unit to control a resonance voltage of a resonance circuit included in the high voltage generation circuit unit and indicates that the voltage has decreased by a predetermined amount. A lighting control unit that outputs a lighting determination signal of the discharge lamp;
A discharge lamp lighting device comprising: A discharge lamp lit by high voltage,
An inverter circuit unit for generating an AC voltage from a DC voltage by opening and closing the switch element in accordance with a rectangular wave-shaped drive control signal, and supplying an AC current to the discharge lamp;
A high voltage generating circuit for generating a high voltage necessary for the discharge lamp to start lighting; and
A voltage detection unit for detecting a voltage generated in the high voltage generation circuit unit;
Based on a detection signal from the voltage detection unit that sends a drive signal to the inverter circuit unit to control a resonance voltage of a resonance circuit included in the high voltage generation circuit unit and indicates that the voltage has decreased by a predetermined amount. A lighting control unit that outputs a lighting determination signal of the discharge lamp;
A device control unit that performs transmission and reception with the lighting control unit;
A video signal processing unit for controlling video signal input and output,
The apparatus control unit controls the video signal processing unit based on a lighting determination signal from the lighting control unit. The projection image according to claim 2, further comprising: a current detection unit configured to detect an alternating current flowing through the discharge lamp after the discharge lamp is stabilized after the device control unit controls the video signal processing unit. Display device. When the current detection unit detects that no alternating current is flowing in the discharge lamp after the discharge lamp has been stably lit, the lighting control unit outputs a signal for stopping video signal processing to the device control unit, 4. The projection type image display device according to claim 3, wherein a discharge lamp lighting control signal which is a signal for lighting the discharge lamp is stopped. 5. The projection type image display apparatus according to claim 4, wherein after the discharge lamp lighting control signal is stopped, the discharge lamp is relighted.

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