JP5537118B2 - High pressure discharge lamp lighting device and image display device using the same - Google Patents

Description

  The present invention relates to a high pressure discharge lamp lighting device and an image display device using the same.

  Projection-type liquid crystal projectors using liquid crystal devices and projection-type DLP projectors using DMD (Digital Micromirror Device) (registered trademark) reduce flickering of high-pressure discharge lamps that are light sources for illumination. In addition, a lighting method in which a pulse current is superimposed on the lamp current (see Patent Documents 1 and 2) and a lighting method in which a triangular waveform is superimposed on the lamp current to deform the lamp current waveform (see Patent Document 3) are employed. .

  Moreover, in the above liquid crystal projector, in order to improve contrast, the liquid crystal device is changed from a normally white system (a system in which the transmissivity or reflectivity is maximized when no voltage is applied to obtain a white screen) to normally black. There is a tendency to change to a system (a system that blocks the light most when no voltage is applied, resulting in a black screen). As a result, in recent liquid crystal projectors, a white bar (horizontal bright line) appears in the horizontal direction of the projection screen. was there.

  This is thought to be caused by the fact that the transistor of the drive driver for the liquid crystal device is turned on due to a photo leak caused by external noise. As a result, the light output increases and the photo leak is likely to occur. As a result, it is estimated that the above-described problem occurs. Therefore, it can be said that the above-described lighting method is not suitable for a liquid crystal projector.

  Therefore, at least in the case of a liquid crystal projector, a method other than the above-described lighting method is required as a method for reducing the flicker of the high pressure discharge lamp. For example, the frequency of the lamp current flowing through the high pressure discharge lamp is shown in FIG. ) (See Patent Document 4) where the frequency is intermittently lower than the lighting frequency, or when the lamp voltage becomes equal to or higher than the predetermined voltage, the high pressure discharge lamp is turned on at a frequency lower than the lighting frequency for a predetermined period. There are proposed a lighting method (see Patent Document 5), a lighting method in which a duty ratio that is a ratio of a positive polarity period and a negative polarity period is intermittently changed as shown in FIG.

  Here, the flickering of the high-pressure discharge lamp will be described in detail. When the high-pressure discharge lamp is lit at a predetermined lighting frequency for a long time, a plurality of protrusions are generated on the electrode according to the lighting time. At the time of polarity reversal, flickering occurs because the arc bright spot moves irregularly between these protrusions. Therefore, in order to reduce flickering, the lamp current frequency is intermittently lower than the lighting frequency, or the duty ratio is changed intermittently to generate unnecessary protrusions at the electrode tip. It is effective to suppress this.

  For example, Patent Document 6 discloses a timing for performing the above flicker countermeasure. When the lamp voltage becomes equal to or higher than a predetermined first voltage, the above flicker countermeasure is started, and then the lamp voltage is set to a predetermined second voltage. When (second voltage <first voltage) or less, the lamp current frequency is returned to a predetermined lighting frequency.

JP 10-501919 A (page 7, line 16-page 7, line 29, and Fig. 1) Japanese Patent Laid-Open No. 2001-244088 (paragraph [0017] and FIGS. 7 and 9) JP 2004-281181 (paragraph [0026] -paragraph [0034] and FIGS. 2 and 3) JP 2006-59790 A (paragraph [0017] -paragraph [0024] and FIGS. 3 and 4) JP 2008-177002 A (paragraph [0046] -paragraph [0048] and FIG. 6) JP 2007-87737 A (paragraph [0030] -paragraph [0035] and FIGS. 3 and 4)

  However, when the timing for performing the flicker countermeasure is determined by the lamp voltage, the lamp voltage may increase more than necessary. For example, FIG. 19 shows a case where a high pressure discharge lamp with a rated power of 200 W is turned on by a high pressure discharge lamp lighting device that does not take measures against flickering and a high pressure discharge lamp lighting device that takes measures against flickering when the lamp voltage reaches 50V. When the flicker countermeasure is taken (solid line e in the figure), the lamp voltage rises by about 8V compared to the case where the lamp voltage is not taken (solid line d in the figure), Thereafter, the lamp voltage gradually decreases, and the lamp voltage is stable when about 40 minutes have passed. This is because when performing power control of a high pressure discharge lamp, constant current control is performed in a low pressure region where the lamp voltage is low, and constant power control is performed in a rated region, as shown in FIGS. In general, the lamp current flowing through the high-pressure discharge lamp is large in the low-pressure region, and as a countermeasure against flicker, the electrode temperature rises more than necessary by changing the duty ratio to a frequency lower than the lighting frequency. This is because the distance between the electrodes is increased by the collapse of the protrusion formed at the electrode tip. That is, according to this conventional example, although the flicker of the high-pressure discharge lamp can be reduced, the lamp voltage increases more than necessary, so that the lamp life may be shortened.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide a high pressure discharge lamp that suppresses a decrease in lamp life by suppressing an increase in lamp voltage while suppressing flickering of the high pressure discharge lamp. The object is to provide a lighting device and an image display device using the same.

The invention of claim 1, reversing a power supply means for supplying predetermined electric power to the high-pressure discharge lamp, a polarity inverting means for inverting the polarity of the lamp current to be applied to the high-pressure discharge lamp alternately, the polarity of the lamp current is to frequency or, and control means for changing the duty ratio is a ratio of the positive period and the negative period of the lamp current, said control means, the frequency of reversing the polarity of the lamp current, a predetermined lighting frequency lower than the lighting frequency from at least one periodically switches the frequency switching mode to the frequency of, or positive polarity period and a negative polarity period are equal first mode of the lamp current, the cathode of the lamp current sexual period negative long second mode than the period of, and the negative third mode is longer than the period of positive polarity period of the lamp current, less respectively Run either the duty ratio switching mode for executing repeated one or more cycles, the start of lighting the high pressure discharge lamp, the electrode temperature of the high pressure discharge lamp has passed the predetermined time is determined to have reached the predetermined temperature And the said control means changes the said predetermined time according to the air cooling conditions of the said high pressure discharge lamp, or the lighting log | history of the said high pressure discharge lamp, It is characterized by the above-mentioned .

According to a second aspect of the invention, in the invention of claim 1, the control means, the predetermined time period from the start of the frequency switching mode or duty ratio changing mode, less than the rated lamp power of the high圧放lamp average power supplied to the high pressure discharge lamp It is characterized by setting to.

According to a third aspect of the present invention, in the second aspect of the present invention, the control means sets the period during which the lamp voltage applied to the high pressure discharge lamp is within a predetermined range as the predetermined period.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the control means changes the predetermined period according to a predetermined average power supplied to the high pressure discharge lamp during steady lighting.

A fifth aspect of the present invention, in any one of the claims 1-4, the control means, after the start of the frequency switching mode or duty ratio changing mode, the average power supplied to the high-pressure discharge lamp is high圧放lamp When the rated lamp power is higher than the rated lamp power, the frequency switching mode or the duty ratio switching mode is stopped.

A sixth aspect of the invention is characterized by comprising the high pressure discharge lamp lighting device according to any one of the first to fifth aspects.

  According to the invention of claim 1, since the frequency switching mode or the duty ratio switching mode is executed when the electrode temperature of the high-pressure discharge lamp reaches a predetermined temperature, the flickering of the high-pressure discharge lamp can be suppressed, and the electrode temperature Can be prevented from rising more than necessary, and as a result, changes in the shape of the protrusions formed on each electrode can be suppressed, so that the lamp voltage can be prevented from rising more than necessary, and a reduction in lamp life can be suppressed. There is an effect.

In addition , it is only necessary to measure the elapsed time from the start of lighting without directly measuring the electrode temperature of the high-pressure discharge lamp, so it is possible to determine whether the electrode temperature of the high-pressure discharge lamp has reached a predetermined temperature with a simple configuration. There is an effect that can be done. Furthermore, since the timing for executing the frequency switching mode or the duty ratio switching mode can be changed according to the air cooling conditions of the high pressure discharge lamp or the lighting history of the high pressure discharge lamp, the electrode temperature of the high pressure discharge lamp can be changed to the air cooling. There is an effect that the temperature can be set corresponding to the condition or lighting history.

According to the invention of claim 2 , since the time from the start of lighting to the start of the frequency switching mode or the duty ratio switching mode is shortened, the rise time of the electrode temperature of the high pressure discharge lamp can be shortened, and as a result Since the transition from the glow discharge after the start to the arc discharge can be promoted, there is an effect that the extinction can be prevented.

According to the invention of claim 3 , since only the lamp voltage applied to the high pressure discharge lamp has to be measured, it is possible to determine whether or not the predetermined period has passed with a simple configuration.

According to the invention of claim 4 , since the predetermined period can be changed according to the average power supplied to the high pressure discharge lamp, the electrode temperature of the high pressure discharge lamp is made to correspond to the supplied average power. There is an effect that it can be set to a different temperature.

According to the fifth aspect of the present invention, when the average power larger than the rated lamp power of the high pressure discharge lamp is supplied to the high pressure discharge lamp, the electrode temperature is increased more than necessary by not executing the frequency switching mode or the duty ratio switching mode. In addition, there is an effect that the rise of the luminous flux can be accelerated.

According to the invention of claim 6 , by using the high pressure discharge lamp lighting device according to any one of claims 1 to 5 , it is possible to provide an image display device in which the flickering of the projection screen is suppressed. There is.

1 is a schematic circuit diagram of a high pressure discharge lamp lighting device according to Embodiment 1. FIG. (A) is a graph showing the transition of the electric power supplied to the high pressure discharge lamp according to the above, (b) is a graph showing the transition of the lamp current applied to the high pressure discharge lamp according to the above, (c) is a graph showing the transition of the lamp current applied to the high pressure discharge lamp. It is a graph which shows transition of the lamp voltage applied to. (A) is a graph which shows transition of the electrode temperature of the high pressure discharge lamp which electric power is supplied by the high pressure discharge lamp lighting device of Embodiment 2, (b) is a graph which shows transition of the lamp voltage same as the above. It is a graph which shows transition of the lamp voltage when a flicker countermeasure is performed with respect to the above and when a flicker countermeasure is not performed. It is sectional drawing same as the above. It is a graph which shows transition of the lamp voltage applied to a high pressure discharge lamp by the high pressure discharge lamp lighting device of Embodiment 3. It is a graph which shows a response | compatibility with the electric power supplied by the high voltage | pressure discharge lamp lighting device of Embodiment 4, and the waiting time until a flicker countermeasure is started after a lighting start. FIG. 6 is a schematic circuit diagram of a high pressure discharge lamp lighting device according to a fifth embodiment. It is a graph which shows a response | compatibility with the amount of air cooling to the high pressure discharge lamp to which electric power is supplied by the same as above, and the gusset time from the start of lighting to the start of flicker countermeasures. It is a schematic circuit diagram of the high pressure discharge lamp lighting device of Embodiment 6. It is a graph which shows a response | compatibility with the lighting history of the high voltage | pressure discharge lamp to which electric power is supplied by the same as above, and the gusset time until a flicker countermeasure is started. (A) is a graph which shows transition of the electric power supplied to a high pressure discharge lamp by the high pressure discharge lamp lighting device of Embodiment 7, (b) is a graph which shows transition of the lamp voltage same as the above. (A) is a graph which shows transition of the electric power supplied to a high pressure discharge lamp by the high pressure discharge lamp lighting device of Embodiment 8, (b) is a graph which shows transition of the lamp voltage same as the above. (A) is a graph which shows transition of the electric power supplied to a high pressure discharge lamp by the high pressure discharge lamp lighting device of Embodiment 9, (b) is a graph which shows transition of the lamp voltage same as the above. (A), (b) is a graph which shows the other example same as the above, respectively. It is a graph which shows transition of the electric power supplied to a high pressure discharge lamp by the high pressure discharge lamp lighting device of Embodiment 10. It is an example of the image display apparatus using the high pressure discharge lamp lighting device in any one of Embodiments 1-10. (A), (b) is a wave form diagram of the flicker countermeasure in the conventional high pressure discharge lamp lighting device. It is a graph which shows transition of the lamp voltage when a flicker countermeasure is performed according to the above and when a flicker countermeasure is not performed. (A), (b) is a graph which shows the relationship between the electric power in the case of carrying out electric power control of a high pressure discharge lamp, lamp current, and a lamp voltage. (A)-(c) is a graph which shows transition of the electric power in the case of carrying out electric power control of a high pressure discharge lamp, a lamp current, and a lamp voltage.

  Embodiments of a high pressure discharge lamp lighting device and an image display device according to the present invention will be described below with reference to the drawings. The high-pressure discharge lamp lighting device according to the present invention is used for lighting a high-pressure discharge lamp such as a high-pressure mercury lamp, a high-pressure sodium lamp, or a metal halide lamp. It is mounted on the image display device.

(Embodiment 1)
FIG. 1 is a schematic circuit diagram of a high-pressure discharge lamp lighting device A according to the first embodiment. The high-pressure discharge lamp lighting device A according to this embodiment is a so-called step-down chopper circuit that steps down a DC power source E to a DC output having a desired voltage value. (Power supply means) 1 and an inverter circuit (polarity inversion means) 2 that alternately inverts the polarity of the lamp current applied to the high-pressure discharge lamp La and supplies high-frequency power to the high-pressure discharge lamp La via the resonance circuit 3 A voltage detection circuit 4 for detecting the output voltage of the step-down chopper circuit 1 and a control circuit (control means) 5 for driving and controlling the step-down chopper circuit 1 and the inverter circuit 2 are provided.

  The step-down chopper circuit 1 has a series circuit of a switching element Q1 and an inductor L1, and the switching element Q1 is turned on / off at an operating frequency or on-duty determined by a PWM control circuit 53 described later, and a desired circuit is obtained. A DC output with a voltage value is obtained.

  The inverter circuit 2 is a so-called full bridge type inverter circuit comprising four switching elements Q2 to Q5 and two drive circuits 21 and 22 for turning on / off these switching elements Q2 to Q5. By turning on / off the switching elements Q2 to Q5 at the operating frequency determined by the full bridge control circuit 52, predetermined high-frequency power is supplied to the high-pressure discharge lamp La. In the present embodiment, two switching elements Q2 and Q3 connected in series are driven and controlled by the drive circuit 21, and two switching elements Q4 and Q5 also connected in series are driven and controlled by the drive circuit 22. .

  The resonance circuit 3 is formed of a series circuit of an inductor L2 and a resonance capacitor C2. Each electrode of the high-pressure discharge lamp La is connected between both ends of the resonance capacitor C2. The high voltage generated by the resonance action of the resonance circuit 3 is applied to the high pressure discharge lamp La, so that the high pressure discharge lamp La is turned on at high frequency.

  The voltage detection circuit 4 includes a series circuit of resistors R2 and R3, detects a divided voltage applied to the resistor R3 in the output voltage from the step-down chopper circuit 1, and outputs the detected voltage to the microcomputer 51 described later. Then, the microcomputer 51 calculates the output voltage of the step-down chopper circuit 1 by calculating backward from the divided voltage value applied to the resistor R3.

  The control circuit 5 includes a microcomputer 51 that performs general control, a full bridge control circuit 52 that controls driving of the drive circuits 21 and 22 of the inverter circuit 2, and a PWM that controls on / off of the switching element Q1 of the step-down chopper circuit 1. A control circuit 53 and signal receiving circuits 55 and 56 for receiving an average power setting signal CS1 and a high pressure discharge lamp ON / OFF signal CS2 to the high pressure discharge lamp La transmitted from the image display device B side are provided. .

  The microcomputer 51 includes a data table 51 a storing various control data, an A / D converter 51 b that converts an analog voltage from the voltage detection circuit 4 into a digital value, and an average power setting received via the signal receiving circuit 55. The power discrimination processing unit 51d that determines the average power supplied to the high-pressure discharge lamp La according to the signal CS1, and the high-pressure discharge lamp La to be turned on according to the high-pressure discharge lamp ON / OFF signal CS2 received via the signal receiving circuit 56 Alternatively, a high-pressure discharge lamp ON / OFF determination processing unit 51f that generates a control signal to be turned off, and a reference signal for power control according to output signals from the power determination processing unit 51d and the high-pressure discharge lamp ON / OFF determination processing unit 51f. The output signals from the reference signal generation processing unit 51c to be generated, the power determination processing unit 51d, and the high-pressure discharge lamp ON / OFF determination processing unit 51f And a time measurement / setting processing unit 51e that outputs predetermined control signals FB1 and FB2 to the full bridge control circuit 52. The reference signal output from the reference signal generation processing unit 51c is D / A. It is converted into an analog voltage Ip by a converter (for example, using an R-2R ladder circuit in this embodiment), and is input to the PWM control circuit 53 as a reference voltage. In the present embodiment, as the microcomputer 51, R8C / 26 group, R8C / 27 group, R8C / 2E group, and R8C / 2F group microcomputers manufactured by Renesas Technology Corp. are used.

  Here, the data table 51a includes a plurality of power value data corresponding to the lamp voltage, data on timing (frequency or duty ratio) for reversing the polarity of the lamp current in each average power and each lighting mode, lamp current The positive polarity and negative polarity periods, the number of times of polarity inversion, and the like are stored. In particular, the power value data is set to have a desired power value (current value) for each lamp voltage Vla. (See FIG. 20). Here, the duty ratio refers to the ratio between the positive polarity period and the negative polarity period of the lamp current.

  The full bridge control circuit 52 is a circuit for performing drive control of the drive circuits 21 and 22 of the inverter circuit 2 in accordance with the control signals FB1 and FB2 from the time measurement / setting processing unit 51e of the microcomputer 51. Then, the control signals FB1 ′ and FB2 ′ are output to the drive circuits 21 and 22, respectively, so that the frequency (or the lamp current duty ratio) at which the polarity of the lamp current is inverted is changed.

  The PWM control circuit 53 is a circuit for controlling on / off (that is, operating frequency or on-duty) of the switching element Q1 of the step-down chopper circuit 1, and a voltage corresponding to the current flowing through the resistor R1 of the step-down chopper circuit 1 is set. Then, the operating frequency or on-duty of the switching element Q1 is set so that the detected voltage matches the reference voltage Ip input through the D / A converter 54.

  Here, the high pressure discharge lamp lighting device A of the present embodiment can communicate with the image display device B through, for example, the UART interface of the microcomputer 51, and the above-described average power setting signal CS1 and the high pressure discharge lamp ON / OFF. An OFF signal CS2 or the like is transmitted to the high pressure discharge lamp lighting device A. In the high pressure discharge lamp lighting device A, the average power corresponding to the received average power setting signal CS1 is supplied to the high pressure discharge lamp La.

  Next, the operation of the high pressure discharge lamp lighting device A will be described. In the microcomputer 51, power data corresponding to the voltage value detected by the voltage detection circuit 4 is selected from the data table 51a and set to a target value, and a voltage signal corresponding to the target value is output from the reference signal generation processing unit 51c. This voltage signal is converted to an analog voltage Ip by the D / A converter 54 and input to the PWM control circuit 53 as a reference voltage.

  In the PWM control circuit 53, the operating frequency or on-duty of the switching element Q1 is set so that the detected voltage corresponding to the current flowing through the resistor R1 of the step-down chopper circuit 1 matches the analog voltage Ip. The switching element Q1 is turned on / off with an on-duty. As a result, the output from the step-down chopper circuit 1 is controlled to a DC output having a desired voltage value.

  In addition, the microcomputer 51 sets the average power determined by the average power setting signal CS1 transmitted from the image display device B side, so that the frequency at which the polarity of the lamp current is inverted, the number of times of polarity inversion at that frequency, etc. The target value is selected from the table 51a, and the control signals FB1 and FB2 corresponding to the target value are output from the time measurement / setting processing unit 51e. The full bridge control circuit 52 outputs control signals FB1 ′ and FB2 ′ corresponding to the control signals FB1 and FB2 to the drive circuits 21 and 22, respectively. The drive circuits 21 and 22 control the control signal FB1 ′. , FB2 ′, switching elements Q2, Q3 and switching elements Q4, Q5 are turned on / off, respectively. As a result, the high-pressure discharge lamp La is supplied with a desired high-frequency power via the resonance circuit 3.

  Here, when the inverter circuit 2 is operated at a high frequency, a predetermined resonance voltage is generated in the resonance circuit 3, and by applying this resonance voltage to the high-pressure discharge lamp La, dielectric breakdown occurs, and the high-pressure discharge lamp La is turned on. However, in order to shift to arc discharge at that time, the inverter circuit 2 is operated at a high frequency (1 kHz or more) for a predetermined time (several hundreds msec to several tens of seconds) and then shifted to a low frequency (1 kHz or less). The power control to the high pressure discharge lamp La is executed after shifting to a low frequency. Specifically, as shown in FIG. 20, constant current control is performed so that the lamp current Ila = I1 until the lamp voltage Vla = V1 (Vla = V2 at the time of dimming), and the lamp voltage Vla = V1 (dimension adjustment). When Vla = V2 during light, constant power control is performed so that lamp power Wla = W1 (Wla = W2 during dimming).

  FIG. 21 is a graph showing transitions of the lamp power Wla, the lamp current Ila, and the lamp voltage Vla with the elapsed time t from the start of lighting on the horizontal axis. Since constant current control is performed until time t1, As shown in FIG. 21 (b), the lamp current Ila = I1 becomes constant, and constant power control is performed after time t1, so that the lamp power Wla = W1 becomes constant as shown in FIG. 21 (a). Then, after time t1, the lamp current Ila gradually decreases as shown in FIG. 21B, and after time t2, Ila = I2 becomes stable. Further, after time t1, the lamp voltage Vla gradually increases as shown in FIG. 21C, and after time t2, Vla = V2 is reached.

  Here, in the control circuit 5 of the present embodiment, as a countermeasure against the flickering of the high-pressure discharge lamp La, the frequency for reversing the polarity of the lamp current is changed from a predetermined lighting frequency to the lighting frequency as shown in FIG. A frequency switching mode for periodically switching to a low frequency (see periods T2 and T4 in the figure) is provided, and the operation thereof will be described below with reference to FIG. As described above, constant current control (lamp current Ila = I1) is performed from the start of lighting to time t1 (see FIG. 2B). At this time, the operation mode of the control circuit 5 is the frequency switching mode. Not. Thereafter, when the electrode temperature of the high-pressure discharge lamp La reaches T1 at time t2 (see FIG. 2C), the operation mode of the control circuit 5 is set to the frequency switching mode, and the cycle shown in FIG. The frequency is switched periodically. When the flicker countermeasure is executed by the frequency switching mode, the flicker is suppressed in the high-pressure discharge lamp La, and the electrode temperature is excessively increased by executing the flicker countermeasure when the electrode temperature reaches T1. As a result, the lamp voltage can be prevented from rising more than necessary. Note that the above electrode temperature may be detected by, for example, a temperature sensor (not shown).

  Thus, according to the present embodiment, since the frequency switching mode is executed when the electrode temperature of the high-pressure discharge lamp La reaches the predetermined temperature T1, flickering of the high-pressure discharge lamp La can be suppressed, and the electrode temperature Can be prevented from rising more than necessary, and as a result, changes in the shape of the protrusions formed on the respective electrodes can be suppressed, so that the lamp voltage Vla can be prevented from rising more than necessary and the lamp life can be prevented from decreasing. it can.

  Here, in the present embodiment, the frequency switching mode is performed as a countermeasure against flickering. However, as shown in FIG. 18B, for example, a first mode in which the positive polarity period and the negative polarity period of the lamp current are equal ( (See periods T1, T3, T5 in the figure), the second mode in which the positive polarity period of the lamp current is longer than the negative polarity period (see period T2 in the figure), the negative polarity period of the lamp current is positive A duty ratio switching mode in which a third mode longer than the period (see period T4 in the figure) is repeated for each one cycle or more may be used. In this case, flickering of the high-pressure discharge lamp La can be suppressed, and the electrodes The temperature can be prevented from rising more than necessary, and as a result, the change in the shape of the protrusions formed on each electrode can be suppressed. Therefore, the lamp voltage Vla can be prevented from rising more than necessary, and the lamp life It is possible to suppress the decrease.

  In the present embodiment, the case where the power supplied to the high-pressure discharge lamp La is two types (see FIG. 20) of full lighting (Full) and dimming lighting (Dim) has been described as an example. There may be one type without having a light source, or a plurality of types so that dimming is possible in a plurality of stages.

  Further, in the present embodiment, as shown in FIG. 1, the high-pressure discharge lamp La is broken down by the resonance circuit 3, but a configuration using an igniter that generates a high-voltage pulse voltage may be used. The timing for starting the igniter may be when the inverter circuit 2 is operating at a high frequency, or the inverter circuit 2 may be operated at a low frequency from the beginning and the dielectric breakdown may be caused by the igniter.

  Furthermore, in this embodiment, as shown in FIG. 2, the electrode temperature at which the countermeasure against flicker is performed is set to the temperature T1 during the constant power control, but the constant current before time t = t1 if the lighting is started. It may be under control, and similarly, the change in the protrusion of the electrode can be suppressed, and an excessive increase in the lamp voltage Vla can be suppressed.

(Embodiment 2)
Embodiment 2 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIGS. The present embodiment is characterized in that the electrode temperature of the high-pressure discharge lamp La is estimated based on the elapsed time t from the start of lighting, and other configurations are the same as those in the first embodiment, and therefore the same components are the same. The description is omitted. Since the circuit configuration is the same as that of the first embodiment, FIG. 1 is referred to when necessary in the following description.

  The high pressure discharge lamp lighting device A of the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5. In the present embodiment, an elapsed time ( A timer (not shown) provided in the microcomputer 51 is used as an elapsed time measuring means for measuring the (predetermined time) t.

  Next, the operation of the high pressure discharge lamp lighting device A will be described with reference to FIG. When the lighting operation of the high-pressure discharge lamp La is started, the timer of the microcomputer 51 is started and time measurement until the electrode temperature of the high-pressure discharge lamp La reaches the predetermined temperature T1 is started. When the timer count time reaches t1, the microcomputer 51 determines that the electrode temperature has reached T1, and starts any of the flicker countermeasures (frequency switching mode or duty ratio switching mode) described in the first embodiment. . In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures.

  Here, the predetermined time t1 until the flicker countermeasure is started is calculated based on the power value supplied to the high-pressure discharge lamp La, the lighting frequency, the air cooling condition described later, and the like. Therefore, although it differs depending on each condition, it is desirable to set it as about a few minutes (1 to 5 minutes) after the high pressure discharge lamp La is lit as a guideline for the predetermined time set value.

  FIG. 4 shows a comparison result between when the rated power of 200 W is supplied to the high-pressure discharge lamp La having a rating of 200 W and the flicker countermeasure is implemented and when it is not implemented. When flicker countermeasures are not implemented, it can be confirmed that the lamp voltage gradually decreases after lighting as shown by the solid line a in the figure. When flicker countermeasures are implemented according to the lamp voltage value, As shown by the solid line c, it can be confirmed that the lamp voltage increases at the beginning of lighting and then gradually decreases. Further, when the flicker countermeasure is implemented after a predetermined time has elapsed from the start of lighting, it can be confirmed that the lamp voltage hardly changes as shown by the solid line b in the figure and is substantially constant.

  Here, as shown in FIG. 5, the high-pressure discharge lamp La used in an image display apparatus such as a projector has an arc generated between both electrodes e1 and e2 of the high-pressure discharge lamp La, and the focal point of the reflector Ref having a parabolic surface. Therefore, when the arc position is moved, the amount of light changes. Since the change in the lamp voltage means that the distance between the electrodes has changed, the position and shape of the protrusions generated on the electrodes have changed, and therefore the arc position has moved. there is a possibility. Therefore, it is desirable that the lamp voltage is constant, and it is understood that it is best to take measures against flickering in the form as shown by a solid line c in FIG.

  Thus, according to this embodiment, it is only necessary to measure the predetermined time t from the start of lighting by the timer of the microcomputer 51 without directly measuring the electrode temperature of the high pressure discharge lamp La. Whether or not the electrode temperature has reached a predetermined temperature can be determined with a simple configuration.

  In the present embodiment, the elapsed time measuring means is constituted by the timer of the microcomputer 51. However, for example, the charging time and the discharging time up to a predetermined voltage are converted into the AD conversion function of the microcomputer 51 by a circuit constituted by a resistor and a capacitor. It is also possible to perform measurement using, or input the output to the microcomputer 51 using a comparator.

(Embodiment 3)
Embodiment 3 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIG. In the above-described second embodiment, the above-described flicker countermeasure is taken from the time when the predetermined time t has elapsed since the start of lighting. However, in the present embodiment, the predetermined time t has elapsed from the start of lighting, and is applied to the high-pressure discharge lamp La. Thus, flicker countermeasures are taken when the lamp voltage V is higher than the predetermined voltage V1. Other configurations are the same as those of the second embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted. Since the circuit configuration is the same as that of the first embodiment, FIG. 1 is referred to when necessary in the following description.

  The high pressure discharge lamp lighting device A of the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5, and the same process as in the second embodiment. A timer (not shown) provided in the microcomputer 51 is used as elapsed time measuring means for measuring time (predetermined time) t.

  Next, the operation of the high pressure discharge lamp lighting device A will be described with reference to FIG. When the lighting operation of the high pressure discharge lamp La is started, the timer of the microcomputer 51 is started, and time measurement until the electrode temperature of the high pressure discharge lamp La reaches a predetermined temperature T1 (see FIG. 2C) is started. When the count time of the timer reaches t1, the microcomputer 51 determines that the electrode temperature has reached T1. Further, the microcomputer 51 monitors the lamp voltage V applied to the high-pressure discharge lamp La, and when the lamp voltage V reaches V1, the measurement time reaches the predetermined time t = t1. Under these conditions, flicker countermeasures (frequency switching mode or duty ratio switching mode) are started. That is, in the present embodiment, flicker countermeasures are taken when a predetermined time t has elapsed from the start of lighting and the lamp voltage V applied to the high-pressure discharge lamp La becomes equal to or higher than the predetermined voltage V1. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures. Therefore, when the lamp voltage V falls below the predetermined voltage V1, the flicker countermeasure is stopped, and a lighting operation at a predetermined lighting frequency is performed.

  Here, the predetermined time t until the flicker countermeasure is started is calculated in the same manner as in the second embodiment, and the predetermined voltage V1 is an abnormal state of the high-pressure discharge lamp La (for example, an abnormal tube wall or an abnormal electrode protrusion). (E.g., growth) or a value determined by the upper limit value of the lamp current. That is, the electrode temperature is set to a value that does not increase more than necessary.

  Thus, according to this embodiment, since the lamp voltage V is measured in addition to the predetermined time t from the start of lighting, it is compared whether or not the electrode temperature of the high-pressure discharge lamp La has reached the predetermined temperature T1. It is possible to discriminate with a simple configuration and improve discrimination accuracy.

Also in the present embodiment, the elapsed time measuring means is not limited to the timer of the microcomputer 51, and the AD conversion of the microcomputer 51 is used to change the charging time and discharging time up to a predetermined voltage by a circuit composed of a resistor and a capacitor. You may make it measure using a function, or may input the output into the microcomputer 51 using a comparator.
In the high pressure discharge lamp lighting device according to the present embodiment, the control means has passed a predetermined time required for the electrode temperature of the high pressure discharge lamp to rise to a predetermined temperature from the start of lighting of the high pressure discharge lamp, and the high pressure discharge lamp. The frequency switching mode or the duty ratio switching mode is executed when the lamp voltage applied to the voltage exceeds a predetermined voltage. According to this configuration, since the lamp voltage is measured in addition to the elapsed time from the start of lighting, it can be determined with a relatively simple configuration whether or not the electrode temperature of the high-pressure discharge lamp has reached a predetermined temperature, There is an effect that the discrimination accuracy can be improved.

(Embodiment 4)
Embodiment 4 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIG. In the present embodiment, the predetermined time from when the lighting is started until the flicker countermeasure is started (that is, the time until the electrode temperature reaches the predetermined temperature) t can be changed according to the average power supplied to the high-pressure discharge lamp La. This is different from the second embodiment. Other configurations are the same as those of the second embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted. Since the circuit configuration is the same as that of the first embodiment, FIG. 1 is referred to when necessary in the following description.

  The high pressure discharge lamp lighting device A according to the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5, and the same as in the second embodiment. As the elapsed time measuring means for measuring the elapsed time (predetermined time) t, a timer (not shown) provided in the microcomputer 51 is used.

  In the high pressure discharge lamp lighting device A of the present embodiment, as shown in FIG. 7, a predetermined time until the flicker countermeasure (frequency switching mode or duty ratio switching mode) is implemented according to the average power P supplied to the high pressure discharge lamp La. t can be changed. For example, when the average power P = P1 supplied to the high-pressure discharge lamp La is set to a predetermined time t = t1, and further when the average power P = P2 (P2 <P1) Is set to a predetermined time t = t2 (t2> t1), and when the average power P = P3 (P3 <P2), the predetermined time t = t3 (t3> t2) is set. Then, when the predetermined time t set according to the average power P elapses, the above flicker countermeasure is started. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures.

  Thus, according to the present embodiment, the timing for performing the flicker countermeasure can be changed according to the average power P supplied to the high-pressure discharge lamp La, so that the electrode temperature of the high-pressure discharge lamp La is The temperature can be set to correspond to the average power P to be supplied.

  In this embodiment, as shown in FIG. 7, when P1> P2> P3, t1 <t2 <t3, that is, the predetermined time t is set shorter as the average power P is larger. t is not limited to this embodiment, and may be set as appropriate according to the average power P supplied to the high-pressure discharge lamp La so that the electrode temperature is in a range where the protrusion shape of the electrode tip does not change. Moreover, in this embodiment, although three types (P1, P2, P3) are illustrated as average electric power, for example, two types may be sufficient and four or more types may be sufficient.

Further, in this embodiment, the elapsed time measuring means is not limited to the timer of the microcomputer 51, and the AD conversion of the microcomputer 51 converts the charging time and the discharging time up to a predetermined voltage by a circuit composed of a resistor and a capacitor. You may make it measure using a function, or may input the output into the microcomputer 51 using a comparator. At that time, in the former method, it is necessary to set a plurality of thresholds according to the type of average power P supplied to the high-pressure discharge lamp La, and in the latter method, the number of comparators according to the type of average power P and The input port of the microcomputer 51 is required.
The high pressure discharge lamp lighting device according to the present embodiment is characterized in that the control means changes the predetermined time according to a predetermined average power supplied to the high pressure discharge lamp during steady lighting. According to this configuration, since the timing for executing the frequency switching mode or the duty ratio switching mode can be changed according to the average power supplied to the high pressure discharge lamp, the electrode temperature of the high pressure discharge lamp is supplied. There is an effect that the temperature can be set to correspond to the average power.

(Embodiment 5)
Embodiment 5 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIGS. In the above-described embodiment 4, the predetermined time t until the flicker countermeasure is started can be changed according to the average power P supplied to the high-pressure discharge lamp La. In this embodiment, FIG. As shown, the predetermined time t can be changed according to the air volume (air cooling condition) F applied to the high pressure discharge lamp La. In the following description, the same components as those of the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  The high-pressure discharge lamp lighting device A of the present embodiment has the same configuration as that of the first embodiment as shown in FIG. 8, and the current high-pressure discharge lamp according to the air-cooled air volume signal CS3 transmitted from the image display device B side. An air-cooled air volume determination processing unit 51g for calculating the air volume F applied to La is provided in the microcomputer 51, and a signal receiving circuit 57 for receiving the air-cooled air volume signal CS3 is provided.

  In the high-pressure discharge lamp lighting device A of the present embodiment, as shown in FIG. 9, a predetermined amount until flicker countermeasures (frequency switching mode or duty ratio switching mode) are started according to the air volume F applied to the high-pressure discharge lamp La. The time t can be changed, and according to FIG. 9, the predetermined time t = t1 is set when the air volume F = F1. Then, when the predetermined time t set according to the air volume F elapses, the above flicker countermeasure is started. Note that the air volume F in the figure is an air volume value obtained by converting the air-cooled air volume signal CS3 by the air-cooled air volume determination processing unit 51g. In this embodiment, when the air volume value is equal to or greater than a predetermined value, the predetermined time t is a constant value ( t = tmin).

  Thus, according to the present embodiment, the timing for performing the flicker countermeasure can be changed according to the air cooling condition of the high pressure discharge lamp La (the air volume F in the present embodiment). The electrode temperature can be set to a temperature corresponding to the air cooling condition.

  In the present embodiment, as shown in FIG. 9, when the air volume F is equal to or greater than a predetermined value, the predetermined time t is a constant value (t = tmin), and the predetermined time t increases as the air volume F decreases. However, FIG. 9 is an example of the present embodiment, and the predetermined time may be calculated from another relational expression as long as the change in the protrusion of the electrode can be suppressed according to the air cooling condition such as the air volume.

  The air cooling condition is not limited to the air volume, and may be, for example, the wind pressure.

(Embodiment 6)
Embodiment 6 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIGS. 10 and 11. In the above-described fifth embodiment, the predetermined time t until the flicker countermeasure is started can be changed according to the air volume (air cooling condition) F of the high-pressure discharge lamp La. However, in this embodiment, the high-pressure discharge lamp is changed. The predetermined time t can be changed according to the lighting history of La. In the following description, the same components as those of the second embodiment are denoted by the same reference numerals and description thereof is omitted.

  The high pressure discharge lamp lighting device A of the present embodiment has the same configuration as that of the first embodiment as shown in FIG. 10, and further, the high pressure discharge lamp lighting device A according to the high pressure discharge lamp replacement signal CS3 transmitted from the image display device B side. A high pressure discharge lamp replacement processing unit 51h for determining whether or not the lamp La has been replaced and a flash memory 51j for storing a lighting history to be described later are provided in the microcomputer 51 and also receives the high pressure discharge lamp replacement signal CS3. A signal receiving circuit 57 is provided. The flash memory may be an external EEPROM or the like.

  FIG. 11 is a graph showing the relationship between the lighting power supplied to the high pressure discharge lamp La and the predetermined time t until the flicker countermeasure (frequency switching mode or duty ratio switching mode) is started. Depending on the magnitude of the lighting power (lighting history) supplied to the high-pressure discharge lamp La and the reference power A, the predetermined time t is set longer or shorter than the reference time t1. Then, when the set time t has elapsed, the above flicker countermeasure is started. In this embodiment, the lighting power supplied to the high-pressure discharge lamp La is written in the flash memory 51j when the light is turned off, and is read from the flash memory 51j as the lighting power for determining the predetermined time t at the next lighting time.

  Here, in the present embodiment, as shown in FIG. 10, the high pressure discharge lamp replacement signal CS3 is transmitted from the image display device B side. When the high pressure discharge lamp La is replaced, the signal receiving circuit 57, the high-pressure discharge lamp replacement signal CS3 is input to the high-pressure discharge lamp replacement processing unit 51h of the microcomputer 51, and the high-pressure discharge lamp replacement processing unit 51h stores the high-pressure discharge before replacement written in the flash memory 51j until then. The lighting history of the lamp La (the lighting power supplied to the high-pressure discharge lamp La) is initialized. Thereafter, similarly, when the high-pressure discharge lamp La is turned off, the lighting power supplied to the replaced high-pressure discharge lamp La is written in the flash memory 51j.

  Thus, according to the present embodiment, the timing for executing the flicker countermeasure can be changed in accordance with the lighting history of the high-pressure discharge lamp La (lighting power in the present embodiment). Therefore, the high-pressure discharge lamp La Can be set to a temperature corresponding to the lighting history.

  In the present embodiment, the case where the previous lighting power (average power) stored in the flash memory 51j is used as the lighting history has been described. However, the lighting history is not limited to the previous lighting power. The lighting time with electric power may be used as the lighting history, or both of them may be used as the lighting history. And the predetermined time t should just be set according to the magnitude of these values and a reference value.

  In this embodiment, the flash memory 51j is initialized when the high-pressure discharge lamp La is replaced. For example, the flash memory 51j is stored so that the lighting history of a plurality of high-pressure discharge lamps La can be stored. When the high pressure discharge lamp La is replaced, the oldest one may be deleted in order.

(Embodiment 7)
Embodiment 7 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIG. The high pressure discharge lamp lighting device A according to the present embodiment reduces the average power supplied to the high pressure discharge lamp La for less than the rated power of the high pressure discharge lamp La for a predetermined period from the start of the flicker countermeasures described in the above embodiments 1 to 6. Since there is a feature in setting, and the other configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals, description thereof is omitted, and reference is made to FIG. 1 as necessary. .

  The high pressure discharge lamp lighting device A of the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5, and has started countermeasures against flickering. As an elapsed time measuring means for measuring the predetermined time, a timer (not shown) included in the microcomputer 51 is used.

  Here, after the start of lighting of the high-pressure discharge lamp La, in order to promote the transition from glow discharge to arc discharge and prevent the lamp from extinguishing, it is necessary to raise the electrode temperature of the high-pressure discharge lamp La. In the embodiment, flicker countermeasures (frequency switching mode or duty ratio switching mode) are started from time t1 after starting lighting (the lamp voltage V = V1 at this time). Then, from time t2 to time t3, the average power P2 smaller than the rated power P1 is supplied to perform constant power control, and after time t3, the rated power P1 is supplied to perform constant power control. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures. Here, in this embodiment, the period from time t1 to time t3 is set as a predetermined period.

  Below, the setting method of said time t1-t3 is demonstrated. First, the time t1 is set to a time from when the inverter circuit 2 is switched from the high frequency operation to the low frequency operation until the electrode temperature reaches an electrode temperature that adversely affects the protrusion at the electrode tip when the flicker countermeasure is started and constant current control is performed. To do. Further, the time t2 is set to a time shorter than the time when the electrode temperature has an adverse effect on the protrusion at the electrode tip when the flicker countermeasure is started and the constant current control is performed, and is longer than the time t1. The time t3 is set to a time during which the lamp voltage is substantially stabilized by the average power P2 smaller than the rated power P1 and longer than the time t2. In other words, the temperature may be set appropriately so that the electrode temperature is such that the change in shape of the protrusion at the tip of the electrode can be suppressed while promoting the transition from glow discharge to arc discharge.

  Thus, according to the present embodiment, since the time from the start of lighting to the start of countermeasures against flickering is shortened, the rise time of the electrode temperature of the high-pressure discharge lamp La can be shortened. The transition from the glow discharge to the arc discharge can be promoted, and the disappearance can be prevented.

  Note that the time t2 and the average power P2 are not limited to the present embodiment, and the time t2 may be within the above-described range, and the average power P2 may be a value smaller than the rated power P1. As shown in 12 (a), it may be not linear but increase linearly.

(Embodiment 8)
Embodiment 8 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIG. The present embodiment is characterized in that a predetermined period (a period during which average power smaller than the rated power is supplied) after the flicker countermeasure is started is set according to the lamp voltage, and the other configuration is the seventh embodiment. Therefore, the same components are denoted by the same reference numerals, and description thereof is omitted. Since the circuit configuration is the same as that of the first embodiment, FIG. 1 is referred to when necessary in the following description.

  The high pressure discharge lamp lighting device A according to the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5. The power supplied to the high-pressure discharge lamp La is set according to the detection voltage (lamp voltage) of the voltage detection circuit 4.

  As shown in FIG. 13, the high-pressure discharge lamp lighting device A of the present embodiment has a flicker countermeasure (frequency switching mode or frequency switching mode) at time t1 when the lighting operation of the high-pressure discharge lamp La starts and the lamp voltage V = V1. Duty ratio switching mode) is started. At this time, the average power (lamp power) P increases proportionally. Then, from time t2 when the lamp voltage V = V2 to time t3 when the lamp voltage V = V3, the average power P2 smaller than the rated power P1 is supplied to perform constant power control, and after the time t3, the rated power P1. To perform constant power control. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures. Here, in this embodiment, a period from time t1 when the lamp voltage V = V1 to time t3 when the lamp voltage V = V3 is set as a predetermined period.

  Thus, according to the present embodiment, since only the lamp voltage V applied to the high-pressure discharge lamp La has to be measured, it is possible to determine whether or not the predetermined period has passed with a simple configuration.

  Note that the lamp voltage V2 and the average power P2 are not limited to those in the present embodiment, and the lamp voltage V2 may be the same as the lamp voltage V1 for starting the countermeasure against flicker, and the average power P2 Is a constant value, but may be increased proportionally if it is smaller than the rated power P1. In other words, the temperature may be set appropriately so that the electrode temperature is such that the change in shape of the protrusion at the tip of the electrode can be suppressed while promoting the transition from glow discharge to arc discharge.

(Embodiment 9)
Embodiment 9 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIGS. 14 and 15. In this embodiment, according to the average power supplied to the high-pressure discharge lamp La at the time of steady lighting, a predetermined period (period during which average power smaller than the rated power is supplied) after the flicker countermeasure is started can be changed. Since there are features and the other configurations are the same as those of the seventh or eighth embodiment, the same components are denoted by the same reference numerals, and description thereof is omitted. Since the circuit configuration is the same as that of the first embodiment, FIG. 1 is referred to when necessary in the following description.

  The high pressure discharge lamp lighting device A of the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5, and has started countermeasures against flickering. As an elapsed time measuring means for measuring the predetermined time, a timer (not shown) included in the microcomputer 51 is used.

  As shown in FIG. 14, the high pressure discharge lamp lighting device A of the present embodiment has a flicker countermeasure (frequency switching mode or frequency switching mode) at time t1 when the lighting operation of the high pressure discharge lamp La starts and the lamp voltage V = V1. Duty ratio switching mode) is started. At this time, the lamp power increases proportionally. Then, from time t2 to time t4, the average power P2 smaller than the rated power P1 is supplied to perform constant power control, and after time t4, the rated power P1 is supplied to perform constant power control. On the other hand, when the average power during steady lighting is P3 (P2 <P3 <P1), the average power P2 is supplied from time t2 to time t3 to perform constant power control, and after time t3 shorter than time t4, the average power is averaged. Constant power control is performed by supplying power P3. That is, according to the present embodiment, the predetermined period t is set shorter as the average power P supplied to the high-pressure discharge lamp La during steady lighting is smaller. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures.

  Next, FIG. 15 is another example showing the operation of the high-pressure discharge lamp lighting device A of the present embodiment. In this case as well, the average power P supplied to the high-pressure discharge lamp La during steady lighting as in FIG. The predetermined period t is set according to the above.

  The flicker countermeasure (frequency switching mode or duty ratio switching mode) is started at time t1 when the lighting operation of the high-pressure discharge lamp La starts and the lamp voltage V = V1. At this time, the lamp power P increases proportionally. Then, from time t2 when the lamp voltage V = V2 to time t4 when the lamp voltage V = V4, the average power P2 smaller than the rated power P1 is supplied to perform constant power control, and after the time t4, the rated power P1. To perform constant power control. On the other hand, when the average power during steady lighting is P3 (P3 <P1), the average power P2 is supplied from time t2 to time t3 to perform constant power control, and after time t3 shorter than time t4, the average power P3 To perform constant power control. That is, also in this example, the predetermined period t is set shorter as the average power P supplied to the high-pressure discharge lamp La during steady lighting is smaller. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures.

  Thus, according to the present embodiment, since the predetermined period t can be changed according to the average power P supplied to the high pressure discharge lamp La, the electrode temperature of the high pressure discharge lamp La is averaged. The temperature can be set to correspond to the electric power P.

  Note that the time t2, the lamp voltage V2, the average power P2, and the average power P1, P3 during steady lighting are not limited to the present embodiment, and flicker countermeasures are started for the time t2 and the lamp voltage V2. It may be the same as the time t1 or the lamp voltage V1. Further, the average power P2 is a constant value in the present embodiment, but may be gradually increased as long as the rated power P1 is not exceeded. Furthermore, the average powers P1 and P3 at the time of steady lighting are not limited to two types of P1 and P3, but may be three or more types, and the magnitude relationship of each power is also in this embodiment. It is not limited. In other words, the temperature may be set appropriately so that the electrode temperature is such that the change in shape of the protrusion at the tip of the electrode can be suppressed while promoting the transition from glow discharge to arc discharge.

(Embodiment 10)
Embodiment 10 of the high pressure discharge lamp lighting device A according to the present invention will be described with reference to FIG. In the present embodiment, when the average power supplied to the high-pressure discharge lamp La exceeds the rated power, there is a feature in that the above-described flicker countermeasure is stopped, and the other configurations are the same as those in the first embodiment. The same reference numerals are given to the constituent elements of and the description is omitted. Since the circuit configuration is the same as that of the first embodiment, FIG. 1 is referred to when necessary in the following description.

  The high pressure discharge lamp lighting device A of the present embodiment includes a step-down chopper circuit 1, an inverter circuit 2, a resonance circuit 3, a voltage detection circuit 4, and a control circuit 5, for example, a temperature sensor (not shown). ) To detect the electrode temperature of the high-pressure discharge lamp La.

  Next, the operation of the high pressure discharge lamp lighting device A will be described with reference to FIG. When the lighting operation of the high-pressure discharge lamp La is started and time t1 when the electrode temperature reaches a predetermined temperature, flicker countermeasures (frequency switching mode or duty ratio switching mode) are started, but at time t2, to the high-pressure discharge lamp La. When the average power P exceeds the rated power P1, the above-described flicker countermeasure is stopped and the lighting mode is shifted to a predetermined lighting frequency. When the average power P decreases to the rated power P1 at time t3, flicker countermeasures are started again. In addition, the shaded area in the figure indicates the implementation area for flicker countermeasures.

  Thus, according to the present embodiment, when the average power P4 larger than the rated power P1 of the high-pressure discharge lamp La is supplied to the high-pressure discharge lamp La, the electrode temperature is increased more than necessary by not performing the flicker countermeasure. In addition, the rise of the luminous flux can be accelerated.

  In addition, you may apply the structure of this embodiment to Embodiment 2-9 mentioned above.

(Embodiment 11)
An embodiment of an image display apparatus B according to the present invention will be described with reference to FIG. The image display apparatus B of the present embodiment is, for example, a projector, and includes a plurality of (three in FIG. 17) high-pressure discharge lamp lighting apparatuses A, high-pressure discharge lamps La in any of the first to tenth embodiments described above. A cooling FAN 6, a power supply unit 7, an input unit 8 for inputting an external signal, and an optical system 9 including optical components such as a lens and a mirror are provided.

  Thus, according to the present embodiment, by using the high pressure discharge lamp lighting device A of any one of the first to tenth embodiments, it is possible to provide the image display device B that suppresses the flickering of the projection screen.

  The image display device B is not limited to a projector, and may be, for example, a vehicle-mounted rear TV.

1 Step-down chopper circuit (power supply means)
2 Inverter circuit (polarity inversion means)
5 Control circuit (control means)
A High pressure discharge lamp lighting device La High pressure discharge lamp

Claims (6)

A power supply means for supplying predetermined electric power to the high-pressure discharge lamp, a polarity inverting means for inverting the polarity of the lamp current to be applied to the high-pressure discharge lamp alternately frequency reverses the polarity of the lamp current or the lamp Control means for changing a duty ratio, which is a ratio between a positive polarity period and a negative polarity period of the current;
The control means is a frequency switching mode in which the frequency for reversing the polarity of the lamp current is periodically switched from a predetermined lighting frequency to at least one frequency lower than the lighting frequency, or a positive polarity period of the lamp current And a first mode in which the negative polarity period is equal, a second mode in which the positive polarity period of the lamp current is longer than the negative polarity period, and a first mode in which the negative polarity period of the lamp current is longer than the positive polarity period. 3 mode, predetermined for one of the at least one cycle or more repeated duty ratio changing mode for executing each of the start of lighting the high pressure discharge lamp, the electrode temperature of the high pressure discharge lamp is determined to have reached a predetermined temperature Runs over time,
The high pressure discharge lamp lighting device, wherein the control means changes the predetermined time according to an air cooling condition of the high pressure discharge lamp or a lighting history of the high pressure discharge lamp. The control means sets an average power supplied to the high-pressure discharge lamp for less than a rated lamp power of the high-pressure discharge lamp for a predetermined period from the start of the frequency switching mode or the duty ratio switching mode. The high pressure discharge lamp lighting device according to 1. The high pressure discharge lamp lighting device according to claim 2 , wherein the control means sets a period during which a lamp voltage applied to the high pressure discharge lamp is within a predetermined range as the predetermined period . The control means, the high pressure discharge lamp lighting device according to claim 2 or 3, wherein changing said predetermined period according to a predetermined average power supplied to the high pressure discharge lamp during stationary lighting. When the average power supplied to the high-pressure discharge lamp is greater than the rated lamp power of the high-pressure discharge lamp after the start of the frequency switching mode or the duty ratio switching mode , the control means, The high-pressure discharge lamp lighting device according to any one of claims 1 to 4, wherein the duty ratio switching mode is stopped . An image display device comprising the high-pressure discharge lamp lighting device according to claim 1 .