JP2010102202A - High-pressure discharge lamp lighting device and image display apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high-pressure discharge lamp lighting device capable of changing a light output for each of color segments of a rotating color filter and capable of suppressing flickering of a high-pressure discharge lamp with a relatively simple control. <P>SOLUTION: When receiving a synchronous timing signal CSO, a current flowing in the high-pressure discharge lamp can be controlled for each of the color segments of the rotating color filter, and polarity reversion stop periods t2 and t3 where the current direction of the high-pressure discharge lamp is not reversed even when receiving the input of the synchronous timing signal CSO are inserted every predetermined time t1, and an electrode temperature is controlled so that the flickering of the high-pressure discharge lamp can be suppressed not by reversing the current direction of the high-pressure discharge lamp before the synchronous timing signal CSO is input the predetermined number of times. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a high-pressure discharge lamp lighting device for lighting a high-intensity high-pressure discharge lamp (HID lamp) such as a high-pressure mercury lamp or a metal halide lamp, and an image display device using the same.

  In recent years, as an image projection device used in projectors, projection televisions, etc., a light beam from a high pressure discharge lamp lit by a high pressure discharge lamp lighting device is irradiated onto a rotating color filter and time-divided into three primary colors of light such as RGB. A method called DLP (Texas Instruments registered trademark) is known in which an image is created using a reflective image display element called DMD (Texas Instruments registered trademark), and the image is projected onto a screen via a projection lens. Yes.

  A schematic configuration of a conventional image projection apparatus is shown in FIG. The high-pressure discharge lamp La is turned on by the high-pressure discharge lamp lighting device 40, and the white light beam output from the high-pressure discharge lamp La is collected by the lens 35a, and the light beam transmitted through the rotating color filter 35c is DMD through the lens 35b. A reflective image display element 35 d called (Texas Instruments registered trademark) is irradiated, and the reflected light is projected onto a screen (not shown) through the projection lens 31. Here, DMD (Texas Instruments registered trademark) is an element (digital micromirror device) in which hundreds of thousands to millions of mirrors that move independently on a CMOS semiconductor are spread out. A grayscale image can be displayed by controlling.

  The set-side control circuit 36 rotates the rotating color filter 35c in accordance with the synchronizing signal of the video signal displayed on the image display element 35d. As the rotating color filter 35c rotates at high speed, the light applied to the image display element 35d is switched between R (red), G (green), B (blue), and W (white). By detecting the rotation of the rotating color filter 35d, the synchronization timing signal CS0 is input to the high-pressure discharge lamp lighting device 40, and an image signal for each color segment is given to the image display element 35d, whereby a color image is displayed on the screen. Can be projected.

  In the example of FIG. 11, W (white) is added in addition to R (red), G (green), and B (blue) of the rotating color filter to improve the brightness. However, the addition of W decreases the resolution of R, G, and B, so that the color saturation performance is lowered. In order to compensate for this, in addition to R, G, B, and W, a complementary color color filter such as C (cyan), M (magenta), and Y (yellow) is used to increase the luminance of the complementary color. Brilliant color technology that improves color saturation is adopted.

  Further, as described in U.S. Pat. No. 5,917,558 (Patent Document 1), JP-A 2006-189485, JP-A 2006-293032, JP-A 2006-349912, JP-A 2007-47234, and JP-A 2007-79330, Variable illumination that can be expressed in colors optimal for each image mode such as theatre, blackboard, presentation, etc. by controlling the lamp power (current) instantaneously to realize multiple rotating color filters with a single rotating color filter. Technology has been adopted. For this reason, the discharge lamp lighting device needs a technique for instantaneously increasing / decreasing the lamp power (current) waveform for each segment (color filter) of the rotating color filter so that the optimum color can be expressed for each image mode. Accordingly, it is necessary to output a power (current) pattern that expresses an optimum color for each image mode.

  In addition, in order for the high-pressure discharge lamp lighting device 40 to detect the switching timing of each color segment of the rotating color filter, synchronization synchronized with the timing of rotating the rotating color filter once or the timing of switching the color segment of the rotating color filter. A timing signal is output from the image display device. It is necessary to match those timings with timings for switching the polarity of electric power (current) supplied to the high-pressure discharge lamp.

  On the other hand, in order to prevent flickering of high-pressure discharge lamps, conventionally, the lamp current waveform has been changed as disclosed in JP-T-10-501919, JP-A-2004-281818, JP-A-2001-244088, JP-A-2003-059684, and the like. However, in the projector of the DLP (Texas Instruments registered trademark) system as described above, the power (current) for each color segment is changed in order to support the variable illumination technology. Therefore, it is difficult to achieve a countermeasure against the lamp flicker by changing the lamp current waveform.

  Therefore, Japanese Patent Laid-Open No. 2008-52047 proposes a method of increasing lamp power (current) during a period (spoke) in which light between the color segments of the rotating color filter is not used. In this method, the period during which the light between each color segment is not used is extremely short, so the lamp current value required for flicker countermeasures can be very large, and the degree of freedom in designing the lamp flicker countermeasures Will be lower.

  In addition, as another means for countermeasures against flickering of a high-pressure discharge lamp, a frequency different from the frequency at the time of normal lighting is inserted as in JP-A-2006-59790 (Patent Document 2) and JP-A-2006-332015 (Patent Document 3) A method has been proposed. If this is realized with a single high-pressure discharge lamp lighting device, the polarity inversion of the lamp current of the high-pressure discharge lamp cannot be synchronized with the rotating color filter, so that the color of the projected image of the projector cannot be expressed.

Therefore, in a DLP (Texas Instruments registered trademark) system projector, the color segment switching of the rotating color filter is synchronized with the polarity reversal of the electric power (current) input to the high-pressure discharge lamp, and it corresponds to the variable illumination technology. There is a need for a discharge lamp lighting device that can reduce the flicker of the lamp with a relatively simple control method.
US 5917558 JP 2006-59790 A JP 2006-332015 A JP 2008-146837 A

  The present invention has been made in view of the above-described points, and is capable of changing the light output for each color segment of the rotating color filter, thereby suppressing the flicker caused by the high-pressure discharge lamp. An object is to provide an electric lamp lighting device.

  In order to solve the above-mentioned problem, the invention of claim 1, as shown in FIG. 11, converts the light beam output from the high-pressure discharge lamp La into a plurality of colors by a plurality of color segments (R, G, B,...). A rotating color filter 35c that is time-divided into two, an image display element 35d that applies modulation by a video signal to a light beam that has passed through the rotating color filter 35c, and a rotating color filter at least once during one rotation of the rotating color filter 35c. A discharge lamp lighting device of an image display device comprising means for outputting a synchronization timing signal CS0 synchronized with the switching time of the color segment 35c, and receives the synchronization timing signal CS0 as shown in FIG. Power supply means 11 capable of controlling the power supplied to the discharge lamp La for each color segment of the rotating color filter 35c, and the synchronization Means 12 for receiving the imming signal CS0 and reversing the current direction of the high-pressure discharge lamp La, and as shown in FIGS. 1 to 3, even when the synchronization timing signal CS0 is input, the current direction of the high-pressure discharge lamp La. Polarity inversion pause periods t2 and t3 that are not inverted at every predetermined time t1, and the polarity inversion pause periods t2 and t3 start from the synchronization timing signal CS0 or a predetermined number of color segments from the synchronization timing signal CS0. Starting from the switching point of the color segment that has elapsed, after the synchronization timing signal CS0 has been input a predetermined number of times, the first synchronization timing signal CS0 is the end point, or a predetermined number of color segments have elapsed from the synchronization timing signal CS0. The color segment switching time point is the end point.

  In the invention of claim 2, in the invention of claim 1, as shown in FIG. 6, a polarity inversion pause period in which the current direction of the high-pressure discharge lamp is positive, and a polarity in which the current direction of the high-pressure discharge lamp is negative The ratio of the inversion suspension period is substantially the same.

  In the invention of claim 3, in the invention of claim 1, as shown in FIG. 7, a polarity inversion pause period in which the current direction of the high-pressure discharge lamp is positive and a polarity in which the current direction of the high-pressure discharge lamp is negative It is characterized in that the ratio of the inversion pause period is different.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, as shown in FIG. 8, when changing the average power input to the high-pressure discharge lamp, the length of the polarity reversal pause period and / or the The interval for inserting the polarity reversal pause period is changed.

  According to a fifth aspect of the present invention, in the first to third aspects of the invention, as shown in FIG. 9, when the control pattern of the power supplied to the high pressure discharge lamp is changed for each color segment, the length of the polarity reversal pause period is increased. And / or changing the interval at which the polarity reversal pause period is inserted.

  According to a sixth aspect of the present invention, in the first to fifth aspects of the present invention, as shown in FIGS. 3B and 3C, the current direction of the high-pressure discharge lamp is reversed first after the polarity reversal pause period ends. The timing is characterized in that it is the end point of the color segment at which the power supplied to the high pressure discharge lamp is maximized.

  A seventh aspect of the invention is an image display device including the high pressure discharge lamp lighting device according to any one of the first to sixth aspects (FIGS. 10 and 11).

  According to the first aspect of the present invention, it is possible to control the power supplied to the high pressure discharge lamp in response to the synchronization timing signal for each color segment of the rotating color filter, thereby enabling optimum color expression for each image mode. In addition, a polarity reversal pause period that does not reverse the current direction of the high-pressure discharge lamp even when a synchronization timing signal is input is inserted every predetermined time, thereby raising the electrode temperature of the high-pressure discharge lamp and melting excess protrusions. Thus, the flickering of the high pressure discharge lamp can be reduced. The polarity reversal pause period starts after the synchronization timing signal is input a predetermined number of times, starting from the synchronization timing signal, or starting from the switching point of the color segment that has passed a predetermined number of color segments from the synchronization timing signal. Since the first synchronization timing signal is the end point, or the switching point of the color segment that has passed a predetermined number of color segments from the synchronization timing signal is the end point, the polarity inversion pause period can be set relatively arbitrarily. A value suitable for a high pressure discharge lamp can be set.

  According to the invention of claim 2, since the ratio of the polarity reversal pause period in which the current direction of the high pressure discharge lamp is a positive direction and the polarity reversal pause period in which the current direction of the high pressure discharge lamp is a negative direction are substantially equal, Both electrodes of the high-pressure discharge lamp are consumed to the same extent. Thereby, a high pressure discharge lamp can be used for a long time.

  According to the invention of claim 3, since the ratio of the polarity inversion pause period in which the current direction of the high pressure discharge lamp is positive and the polarity inversion pause period in which the current direction of the high pressure discharge lamp is negative are different, Even if the temperature of both electrodes becomes unbalanced due to air cooling conditions of the high-pressure discharge lamp, reflecting mirrors, etc., both electrodes of the high-pressure discharge lamp are consumed to the same extent because the temperature balance of both electrodes can be made uniform. I will do it. Thereby, a high pressure discharge lamp can be used for a long time.

  According to the fourth aspect of the present invention, when changing the average power supplied to the high-pressure discharge lamp, the length of the polarity inversion pause period and / or the interval for inserting the polarity inversion pause period is changed. It can be set to a condition that can reduce flickering of the high-pressure discharge lamp suitable for each average power input to the lamp.

  According to invention of Claim 5, when changing the control pattern of the electric power supplied to a high pressure discharge lamp for every color segment, the length of a polarity reversal stop period and / or the space | interval which inserts the said polarity reversal rest period Therefore, it is possible to set a condition that can reduce flickering of the high-pressure discharge lamp adapted to the control pattern of the electric power supplied to the high-pressure discharge lamp in each image mode.

  According to the sixth aspect of the present invention, the timing of reversing the current direction of the high pressure discharge lamp first after the end of the polarity reversal pause period is the end time of the color segment at which the power supplied to the high pressure discharge lamp is maximum. Since the degree of freedom of design for increasing the electrode temperature of the high-pressure discharge lamp is increased, it is possible to set the condition that the flickering of the high-pressure discharge lamp can be further reduced.

  According to the seventh aspect of the present invention, it is possible to employ a variable illumination technique that can be expressed in colors optimal for each image mode, and to provide an image display device that is less flickered by a high-pressure discharge lamp.

(Embodiment 1)
The high-pressure discharge lamp lighting device of the present invention can instantaneously switch the lamp current to the high-pressure discharge lamp for each color segment of the rotating color filter, as shown in FIGS. As in a), the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0 synchronized with the switching timing of the segment of the rotating color filter transmitted from the image display device, but every predetermined time t1. , (B), (c), polarity inversion pause periods t2, t3 are provided in which the current direction of the high-pressure discharge lamp is not reversed even when the synchronization timing signal CS0 is input.

  The polarity inversion pause periods t2 and t3 start from the synchronization timing signal CS0 as shown in FIGS. 1 and 3, or as shown in FIG. 2, a predetermined number of color segments have elapsed from the synchronization timing signal CS0. After the color segment switching time point is set as the starting point, after the synchronization timing signal CS0 is input a predetermined number of times, the first synchronization timing signal CS0 is the end point, as shown in FIG. 1, or as shown in FIGS. The switching point of the color segment that has passed a predetermined number of color segments from the synchronization timing signal CS0 is the end point.

  A circuit diagram of a high pressure discharge lamp lighting device for carrying out the control of the present invention is shown in FIG. This lighting device is a combination of a step-down chopper circuit 11 and a polarity inversion circuit 12. The DC voltage output from the power supply circuit E is stepped down to an appropriate voltage by the step-down chopper circuit 11 and converted into a rectangular wave AC voltage by the polarity inversion circuit 12. The output of the polarity inverting circuit 12 is connected to a starting resonance circuit 13 composed of a capacitor C2 and an inductor L2, and a discharge lamp La is connected to both ends of the capacitor C2.

  The power supply circuit E includes, for example, a rectifier that rectifies a commercial AC power supply and a step-up chopper circuit for power factor correction and smoothing, and outputs a DC voltage of, for example, several hundred volts.

  The step-down chopper circuit 11 includes a switching element Q1 that is switched at a high frequency, an inductor L1 for energy storage, a diode D1 for energizing a regenerative current, a smoothing capacitor C1, and a resistor R1 for current detection. Thus, by variably controlling the pulse width of the switching element Q1, the DC voltage output from the power supply circuit E is stepped down to charge the capacitor C1.

  The polarity inversion circuit 12 is a full bridge inverter circuit composed of a series circuit of switching elements Q2 and Q3 connected in parallel to both ends of the capacitor C1 and a series circuit of switching elements Q4 and Q5, and the switching elements Q2 and Q5 are turned on. The switching circuit Q3, Q4 is turned off, the switching elements Q2, Q5 are turned off, and the switching elements Q3, Q4 are turned on alternately so that the polarity of the DC voltage of the capacitor C1 is reversed and the load circuit To supply a rectangular wave AC voltage.

  The load circuit includes a resonance circuit 13 including a capacitor C2 and an inductor L2, and a discharge lamp La connected in parallel to both ends of the capacitor C2. The discharge lamp La is a high-intensity high-pressure discharge lamp (HID lamp) such as a high-pressure mercury lamp or a metal halide lamp.

  When starting the lighting of the discharge lamp La, the control circuit 14 alternately turns on and off the switching elements Q2 and Q5 and the switching elements Q3 and Q4 disposed at the diagonal positions, thereby causing the resonance circuit 13 to turn on and off. A high frequency voltage of several tens of kHz to several hundreds of kHz is applied to both ends. This high-frequency voltage is boosted by the resonance action of the resonance circuit 13, a high-voltage resonance voltage is generated in the capacitor C2, and is applied to the discharge lamp La, causing dielectric breakdown and lighting the discharge lamp La. Then, for a while (from several hundred msec to several tens of seconds) to shift to arc discharge, a low-frequency rectangular wave voltage of several tens to several hundreds Hz is applied to the discharge lamp La to turn on the lamp. maintain.

  Although not shown, an igniter circuit that generates a high voltage pulse for starting or restarting the discharge lamp La may be used in combination with the resonance circuit 13. The igniter circuit may be activated when the polarity inverting circuit 12 is operated at a high frequency, or the polarity inverting circuit 12 is operated at a low frequency from the beginning, and the discharge lamp La is dielectrically lit by a high voltage pulse of the igniter circuit to be lit. It is good also as a structure.

  The voltage detection circuit 15 divides and detects the output voltage of the step-down chopper circuit 11 by a series circuit of resistors R2 and R3. The detection output of the voltage detection circuit 15 is input to the microcomputer 20 of the control circuit 14 and converted into a digital value by the A / D converter 21. The power control reference signal generation processing unit 22 of the microcomputer 20 calculates a lamp power control amount for each color segment with reference to the data table 23 according to the voltage value detected by the lamp voltage detection circuit 15, and performs D / A The converter 16 converts the power command voltage Ip. The D / A converter 16 uses, for example, an R-2R resistance ladder circuit. The PWM control circuit 17 performs chopper control by comparing the detected voltage of the chopper current detected by the current detection resistor R1 with the power command voltage Ip, thereby controlling the lamp power (lamp current).

  As the microcomputer 20 of the control circuit 14, for example, R8C / 26, 27 group or R8C / 2E, 2F of R8C / Tiny series of Renesas Technology Corp. is used. Detection of the level change of the synchronization timing signal CS0 from the image display device and measurement of the time are realized by using a pulse period measurement mode of the timer function of the microcomputer 20 or the like. In FIG. 5, the functions of the microcomputer 20 are shown in blocks.

  The command determination processing unit 25 receives an output signal of a command signal receiving circuit composed of the photocoupler PC1 and the resistor R4, receives the command signal CS1 from the image display device, and receives the average power and power (indicated from the image display device side) Current) pattern. The command signal CS1 also serves as an ON / OFF command signal for the high pressure discharge lamp. The instruction of the average power and the power (current) pattern to be supplied to the discharge lamp La is performed by, for example, UART communication. By matching the communication command and the like with the image display device side and receiving the command, the discharge lamp lighting device operates with an average power and a power (current) pattern suitable for the command. Data of average power and power (current) pattern suitable for each command is stored in the data table 23 in advance.

  Here, the power (current) pattern from the image display device is a waveform of the lamp current during one rotation of the rotating color filter, and the power (current) supplied to the high-pressure discharge lamp during the one rotation. Including the case of polarity inversion (see FIG. 12D and the like).

  The data table 23 first stores power control amount data corresponding to the lamp voltage Vla used for control from the start of the high-pressure discharge lamp to the stable lighting state. In addition, in order to switch the power (current) to be supplied to the high-pressure discharge lamp for each color segment of the rotating color filter after reaching the stable lighting state, the power control amount data for each color segment includes the lamp voltage Vla. It is set for each. Further, as will be described later, the data table 23 stores data for calculating each segment time (such as the angle of each segment of the rotating color filter) and timing data for inverting the polarity of the full bridge.

  Each segment time calculation processing unit 26 receives the output signal of the synchronization timing signal receiving circuit composed of the photocoupler PC2 and the resistor R5, detects the level change timing of the synchronization timing signal CS0 from the image display device, and rotates the color filter. The time of each segment of is calculated.

  The time measurement / setting processing unit 24 refers to the synchronization timing signal CS0 and the time of each segment of the rotating color filter, performs the timing control of the polarity inversion in the polarity inverting circuit 12, and measures the time. In contrast, the full bridge control signals FB1 and FB2 are output.

  The drive circuit 12a controls the high-potential side switching element Q2 and the low-potential side switching element Q3 to be alternately turned on and off in response to the full-bridge control signal FB1 'from the full-bridge control unit 12c. The drive circuit 12b controls the high-potential side switching element Q4 and the low-potential side switching element Q5 to be alternately turned on and off in response to the full-bridge control signal FB2 'from the full-bridge control unit 12c.

  The polarity inversion by the polarity inversion circuit 12 is, for example, the timing of the level change of the synchronization timing signal CS0 as shown in FIG. 12C, or the timing of switching the segment of the rotating color filter as shown in FIG. To do. In order to simplify the explanation, FIG. 12 shows the timing of polarity inversion by the synchronization signal CS0 in the case of a rotating color filter of the three primary colors of RGB, but it includes a filter of W or complementary colors (C, Y, etc.). Is the same.

  The time of each segment is calculated from the time T1 of the synchronization timing signal CS0 and the segment angle stored in the data table when the synchronization timing signal is of the edge system as shown in FIG. To do. When the synchronization timing signal CS0 is synchronized with the angle of one color segment as shown in FIG. 12B, the time of each color segment is determined from the time T2 and the segment angle stored in the data table. Is calculated. In this way, it is possible to cope with a case where the rotational speed of the rotating color filter changes. The rotational speed of the rotating color filter is generally set to a basic rotational speed of 50 or 60 Hz, and is operated at about 2 to 3 times the basic rotational speed. The detection direction of the level change of the synchronization timing signal CS0 is detected when the photocoupler having a small rounded signal waveform is ON (when the photocoupler output changes from H to L).

  FIG. 4 illustrates the relationship between the level change of the synchronization timing signal CS0, the polarity inversion timing, and the boundary of the color segment of the rotating color filter. FIGS. 4A and 4A are examples in which the synchronization timing signal CS0 is input once while the rotating color filter rotates once. FIG. 4B shows an example in which the synchronization timing signal CS0 is input twice while the rotating color filter rotates once.

  The timing of the starting point so as not to reverse the current direction of the high-pressure discharge lamp is the same timing as the level change of the synchronization timing signal CS0 in the examples of FIGS. 4 (a) and 4 (b). On the other hand, in the example of FIG. 4 (a ′), the timing is different from that of the synchronization timing signal CS0, and a predetermined number (in this example, R and Y twice) of color segments after the level change of the synchronization timing signal CS0. This is the timing of color segment switching after the elapse of time. By setting the start and end points of the period during which the current direction of the high-pressure discharge lamp is not reversed even when the synchronization timing signal CS0 is input as the time when the synchronization timing signal is input or when the color segment is switched, Since the time can be arbitrarily set, a value suitable for the high pressure discharge lamp can be set.

  When the command signal CS1 from the image display device side instructs the ON (lighting) of the high-pressure discharge lamp, the polarity inverting circuit 12 is operated at a high frequency, thereby generating a high voltage by the resonance action of the resonance circuit 13 and releasing it. The lamp La is dielectrically broken and started, and the operation proceeds to a low frequency operation. Thereafter, the lamp current Ila and the lamp power Wla are controlled according to the lamp voltage Vla according to the control characteristics set in the data table 23.

  Lamp current control at start-up (lamp power control) performs constant current control so that the lamp current is constant until the lamp voltage Vla reaches a predetermined value, and after the lamp voltage Vla reaches a predetermined value, Constant power control is performed so that the lamp power Wla is constant.

  In addition, the lamp power control after reaching the stable lighting state is performed in the data table 23 according to the voltage value detected by the lamp voltage detection circuit 15 in the data table 23 according to the lamp power control amount required for each color segment of the rotating color filter. The D / A converter 16 converts the electric power command voltage Ip with reference to the power command voltage Ip. As a result, as shown in FIGS. 1 to 3, the lamp current to the high-pressure discharge lamp can be instantaneously switched for each color segment of the rotating color filter.

  The timing for detecting the lamp voltage is, for example, in a segment where the input power (current) to the high-pressure discharge lamp is 100% (when the rectangular wave is turned on), or for a long time (the angle occupied in the rotating color filter) Large) color segment, or a segment in which the input power (current) to the high-pressure discharge lamp is continuous at the same value, or a segment in which the input power (current) to the high-pressure discharge lamp is the same value in each image mode Of these, at least one timing is performed.

  The details of the operation of this embodiment are as shown in FIGS. 1, 2, and 3, for example. In this example, the synchronization timing signal CS0 is transmitted from the image display device once every time the rotating color filter rotates once. In this example, the color segment corresponding to the synchronization timing signal CS0 is R. The configuration of the rotating color filter is not particularly limited, but in the example of FIGS. 1 to 3, the color segments are switched in the order of R → Y → G → W → C → B.

  The normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0 is t1 in FIGS. 1 to 3, and the lamp current waveform in that period is the waveform shown in FIG. . The normal lighting period t1 is calculated by a timer or the like in the microcomputer 20, or is calculated from the number of receptions of the synchronization timing signal CS0.

  After the normal lighting period t1, the polarity inversion pause period in which the current direction of the high-pressure discharge lamp is not reversed even when the synchronization timing signal CS0 is input is t2 and t3 in FIGS. These are waveforms shown in FIGS. 1 to 3 (b) and (c). The polarity reversal pause periods t2 and t3 are calculated by a timer or the like in the microcomputer 20, or are calculated from the number of receptions of the synchronization timing signal CS0. In the example of FIGS. 1 to 3, the current direction of the high-pressure discharge lamp is not reversed while the synchronization timing signal CS0 is received six times, and the polarity of seven lamp waveforms is not reversed.

  The end timing of the polarity reversal pause period is the time when the synchronization timing signal is received for the seventh time in FIG. 1, and the time when yellow Y and green G of the color segment of the rotating color filter are switched in FIG. 3 is the time of switching between white W and cyan C of the color segment of the rotating color filter, and the current direction of the high-pressure discharge lamp is reversed at that time.

  According to the present embodiment, the synchronization timing signal CS0 transmitted from the image display device to the discharge lamp lighting device is a simple signal as compared with Japanese Patent Application Laid-Open No. 2008-146837 (Patent Document 4). The synchronization timing signal disclosed in Japanese Patent Application Laid-Open No. 2008-146837 is a complex signal in which the synchronization timing signal is always transmitted at the timing of switching each color segment, and the synchronization timing signal is modulated to identify one rotation of the rotating color filter. Therefore, the image display device and the control unit of the high-pressure discharge lamp require complicated processing.

  As described above, the synchronization timing signal CS0 transmitted from the image display device to the discharge lamp lighting device is a simple signal as compared with Japanese Patent Application Laid-Open No. 2008-146837, which places a burden on the control processing unit of the image display device. In addition, the signal processing of the high pressure discharge lamp device is facilitated, and the input power (current) to the high pressure discharge lamp for each color segment of the rotating color filter is not limited as compared with the special table 2008-521047, and is desired. Can be set to a value. In Japanese Translation of PCT International Application No. 2008-52047, there is a possibility that the lamp current value required for flicker countermeasures may be a very large value, and the degree of freedom in design for lamp flicker countermeasures is reduced.

  In this way, since the input power (current) can be set to a desired value, it is possible to achieve optimum color expression for each image mode, and the current direction of the high-pressure discharge lamp is reversed even when the synchronization timing signal CS0 is input. Since the periods t2 and t3 not to be inserted are inserted at every predetermined time t1, the electrode temperature of the high-pressure discharge lamp rises and it becomes possible to melt excess protrusions, and flickering of the high-pressure discharge lamp can be reduced.

  To explain in more detail, the flicker caused by the high-pressure discharge lamp is that when the high-pressure discharge lamp is used for a long time, the electrode shape becomes rough as the lifetime elapses, and a plurality of protrusions are generated, When the polarity of the current supplied to the high-pressure discharge lamp is reversed, the arc bright spot is irregularly moved between the generated projections. For this measure, the projection of the electrode tip is usually formed by reversing the current direction of the high-pressure discharge lamp with a synchronization timing signal CS0 synchronized with the switching timing of the segment of the rotating color filter transmitted from the image display device. Whenever the predetermined time t1 elapses, polarity inversion pause periods t2 and t3 are provided in which the current direction of the high-pressure discharge lamp is not reversed even when the synchronization timing signal CS0 is input. In the polarity reversal pause periods t2 and t3, the surface temperature of the electrode is raised and the excess protrusion is melted so as not to generate a plurality of protrusions generated around the protrusion generated at the beginning of the electrode tip. Thereby, the bright spot of the arc does not move irregularly between the plurality of generated protrusions, and flicker (flicker) due to the high-pressure discharge lamp can be reduced.

  By adopting such a configuration and operation, the synchronization timing signal CS0 transmitted from the image display device to the discharge lamp lighting device is a simple signal that can express colors optimal for each image mode, and is capable of high-pressure discharge. The flickering of electric light can be reduced.

(Embodiment 2)
The present embodiment is characterized in that the ratio of the polarity inversion pause period in which the current direction of the high-pressure discharge lamp is positive and the polarity inversion pause period in which the current direction of the high-pressure discharge lamp is negative are substantially equal. The circuit configuration may be the same as in the first embodiment.

  The operation of this embodiment is as shown in FIG. 6, for example. The vertical stripe period in the figure is a normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the normal lighting period and the details of the lamp current pattern are the same as in FIG.

  Further, the black square period in the figure is a polarity inversion pause period in which the current direction of the high pressure discharge lamp is not inverted by the synchronization timing signal. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the polarity inversion pause period and the details of the lamp current pattern are the same as those shown in FIGS.

  The example of FIG. 6A is an example in which the polarity of the polarity inversion pause period in which the current direction of the high-pressure discharge lamp is not inverted by the synchronization timing signal CS0 is alternately inverted every time.

  In the example of FIG. 6B, the polarity of the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal CS0 is the same polarity for a predetermined number of times (three times in the illustrated example). It is.

  In the example of FIG. 6C, the polarity of the polarity inversion pause period in which the current direction of the high pressure discharge lamp is not reversed by the synchronization timing signal CS0 is returned to the normal lighting period in which the current direction of the high pressure discharge lamp is reversed by the synchronization timing signal CS0. In this example, the number of positive and negative times is controlled to be an even number (equivalent number).

  In the example of FIG. 6D, the polarity of the polarity inversion pause period in which the current direction of the high pressure discharge lamp is not reversed by the synchronization timing signal CS0 is returned to the normal lighting period in which the current direction of the high pressure discharge lamp is reversed by the synchronization timing signal CS0. In this example, the number of positive and negative times is controlled to be an odd number.

  By adopting such a configuration and operation, the ratio of the polarity inversion pause period in which the current direction of the high-pressure discharge lamp is positive and the polarity inversion pause period in which the current direction of the high-pressure discharge lamp is negative are substantially equal. Therefore, both electrodes of the high-pressure discharge lamp are consumed to the same extent. Thereby, a high pressure discharge lamp can be used for a long time. Although various patterns can be considered as in the example of FIG. 6, the operation pattern may be set to be suitable for each high-pressure discharge lamp.

(Embodiment 3)
The present embodiment is characterized in that the ratio of the polarity inversion pause period in which the current direction of the high pressure discharge lamp is positive and the polarity inversion pause period in which the current direction of the high pressure discharge lamp is negative are different. The circuit configuration may be the same as in the first embodiment.

  The operation of this embodiment is as shown in FIG. The vertical stripe period in the figure is a normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the normal lighting period and the details of the lamp current pattern are the same as in FIG.

  Further, the black square period in the figure is a polarity inversion pause period in which the current direction of the high pressure discharge lamp is not inverted by the synchronization timing signal. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the polarity inversion pause period and the details of the lamp current pattern are the same as those shown in FIGS.

  The example of FIG. 7A is an example in which the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal is set to different periods t2, t3 (t2> t3) for each polarity.

  The example of FIG. 7B is an example in which the polarity is reversed in the example of FIG.

  In the example of FIG. 7C, the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal is the same for each time, but the number of positive and negative times is different (positive and negative). 2 times in the direction and 1 time in the negative direction).

  The example of FIG. 7 (d) is an example in which the polarity is reversed in the example of FIG. 7 (c) (once in the positive direction and twice in the negative direction).

  By adopting such a configuration and operation, when the temperature of both electrodes is unbalanced due to the air cooling conditions of the high-pressure discharge lamp and the reflecting mirror, the temperature of both electrodes can be adjusted by adjusting the positive / negative ratio in the current direction. Since the balance can be made uniform, both electrodes of the high pressure discharge lamp are consumed to the same extent. Thereby, a high pressure discharge lamp can be used for a long time. As the operation pattern, various patterns are conceivable as in the example of FIG. 7, but the operation pattern may be set so as to be suitable for each high-pressure discharge lamp and air cooling conditions.

(Embodiment 4)
In the present embodiment, in the above-described first to third embodiments, when changing the average power input to the high pressure discharge lamp, the length of the polarity inversion pause period and / or the interval for inserting the polarity inversion pause period ( The length of the normal lighting period t1) is changed. The circuit configuration may be the same as in the first embodiment.

  The operation of this embodiment is as shown in FIG. 8, for example. The vertical stripe period in the figure is a normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the normal lighting period and the details of the lamp current pattern are the same as in FIG.

  Further, the black square period in the figure is a polarity inversion pause period in which the current direction of the high pressure discharge lamp is not inverted by the synchronization timing signal. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the polarity inversion pause period and the details of the lamp current pattern are the same as those shown in FIGS.

  In this example, average power P1> average power P2. The vertical axis of the lamp current represents the amplitude (rough envelope), and the lamp current amplitude is controlled to be lower in the period of the average power P2 than in the period of the average power P1.

  In the example of FIG. 8 (a), when the average power input to the high pressure discharge lamp is switched, the length of the polarity reversal pause period in which the current direction of the high pressure discharge lamp is not reversed by the synchronization timing signal CS0 is changed (still t2). In this example, the length of the normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal is changed as t1 → t1 ′, t1 ′ → t1. That is, the average power P1 is controlled so that the length of the normal lighting period is t1, while the average power P2 (<P1) is controlled so that the length of the normal lighting period is t1 ′ (<t1). .

  In the example of FIG. 8B, when the average power input to the high-pressure discharge lamp is switched, the length of the normal lighting period for reversing the current direction of the high-pressure discharge lamp with the synchronization timing signal CS0 is changed (still t1). In this example, the length of the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal is changed as t2 → t2 ′, t2 ′ → t2. That is, the average power P1 is controlled so that the polarity reversal pause period is t2 while the average power P2 (<P1) is t2 ′ (> t2). ing.

  In the example of FIG. 8C, when the average power input to the high-pressure discharge lamp is switched, the length of the normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0 is changed from t1 to t1 ′, t1. In this example, the length of the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal CS0 is changed as t2 → t2 ′ and t2 ′ → t2. is there. That is, the average lighting period is t1 and the polarity inversion pause period is t2 at the average power P1, whereas the normal lighting period is t1 ′ (<P1) at the average power P2 (<P1). t1) The length of the polarity reversal pause period is controlled to be t2 ′ (> t2).

  By adopting such a configuration and operation, it is possible to set conditions that can reduce flickering of the high-pressure discharge lamp suitable for each average power input to the high-pressure discharge lamp. Although various patterns can be considered as the operation pattern, it may be set so as to be suitable for each high-pressure discharge lamp. The lamp power value is also two types in this example, but the same applies when switching to a plurality of three or more types of power.

(Embodiment 5)
In this embodiment, when changing the control pattern of the power supplied to the high-pressure discharge lamp for each color segment in the above-described first to third embodiments, the length of the polarity inversion pause period and / or the polarity inversion It is characterized in that the interval for inserting the pause period (the length of the normal lighting period t1) is changed. The circuit configuration may be the same as in the first embodiment.

  The operation of this embodiment is as shown in FIG. 9, for example. In this example, in addition to the lamp current waveform pattern 1 illustrated in FIGS. 1 to 3, the lamp current waveform pattern 2 illustrated in FIGS. 9D and 9E can be switched and used.

  The vertical stripe period in the figure is a normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the normal lighting period and the details of the lamp current pattern are the same as in FIG.

  Moreover, the period (d) of the diagonal stripe in the figure is also a normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0. The relationship between the synchronization timing signal CS0 and the polarity inversion timing in the normal lighting period (d) and the details of the lamp current pattern are as shown in (d) of FIG.

  Further, the black square period in the figure is a polarity inversion pause period in which the current direction of the high pressure discharge lamp is not inverted by the synchronization timing signal. The relationship between the synchronization timing signal CS0 and the polarity inversion timing during the polarity inversion pause period and the details of the lamp current pattern are the same as those shown in FIGS.

  Furthermore, the diagonal stripe period (e) in the figure is also a polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal. The relationship between the synchronization timing signal CS0 and the polarity inversion timing in the polarity inversion pause period (e) and the details of the lamp current pattern are as shown in FIG. 9 (e).

  In the example of FIG. 9 (a), when the current (power) pattern supplied to the high pressure discharge lamp is changed, the length of the polarity reversal pause period in which the current direction of the high pressure discharge lamp is not reversed by the synchronization timing signal CS0 is (t2 In this example, the length of the normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0 is changed as t1 → t1 ′, t1 ′ → t1.

  In the example of FIG. 9B, when the current (power) pattern input to the high-pressure discharge lamp is changed, the length of the normal lighting period in which the current direction of the high-pressure discharge lamp is reversed by the synchronization timing signal CS0 is still t1. This is an example in which the length of the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal CS0 is changed as t2 → t2 ′, t2 ′ → t2.

  In the example of FIG. 9C, when the current (power) pattern to be applied to the high pressure discharge lamp is changed, the length of the normal lighting period in which the current direction of the high pressure discharge lamp is reversed by the synchronization timing signal CS0 is changed from t1 to t1. The length of the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal CS0 is changed as t2, t2, and t2 ', t2. This is an example.

  By adopting such a configuration and operation, it is possible to set conditions that can reduce flickering of the high-pressure discharge lamp that conforms to the pattern of electric power (current) input to the high-pressure discharge lamp in each image mode. Although various patterns can be considered as in the above example, the operation pattern may be set so as to be suitable for each high-pressure discharge lamp. The lamp current waveform patterns are also two types in this example, but the same applies to the case of a plurality of three or more types of lamp current waveform patterns.

(Embodiment 6)
In the present embodiment, in the above-described first to fifth embodiments, the color segment in which the power supplied to the high-pressure discharge lamp is maximized is the timing at which the current direction of the high-pressure discharge lamp is reversed first after the polarity reversal suspension period ends. It is characterized by being the end point of. The circuit configuration may be the same as in the first embodiment.

  The operation of this embodiment is, for example, as shown in FIGS. The end point of the polarity reversal pause period in which the current direction of the high-pressure discharge lamp is not reversed by the synchronization timing signal is indicated by the lamp current waveform in the lower stage of FIGS. 3B and 3C and FIG. 9E. At the end of the segment (in this example, white (W)) in which the largest power (current) is input in the current waveform pattern. The target segment at the end may be stored as one data in the data table of each lamp current waveform pattern.

  By adopting such a configuration and operation, the degree of freedom in design for increasing the electrode temperature of the high-pressure discharge lamp is increased, so that the conditions for reducing the flicker of the high-pressure discharge lamp can be set.

(Embodiment 7)
The high pressure discharge lamp lighting device of each of the above embodiments is used for lighting a high pressure discharge lamp that is a light source of a projector. FIG. 10 is a schematic diagram showing the internal configuration of the projector. In the figure, 31 is a projection lens, 32 is a power supply unit, 33a, 33b and 33c are cooling fans, 34 is an external signal input unit, 35 is an optical system, 36 is a main control board, 40 is a discharge lamp lighting device, and La is It is a discharge lamp. A main control board is mounted in a frame indicated by a broken line. In the middle of the optical system 35, image display means (a transmissive liquid crystal display element or a reflective image display element) that transmits or reflects light from the discharge lamp La is provided. The optical system 35 is designed to project the reflected light onto the screen. Thus, the discharge lamp lighting device 40 is mounted inside the projector 30 together with the discharge lamp La. By employing the discharge lamp lighting device of the present invention, flicker caused by the lamp can be reduced.

  Note that the high pressure discharge lamp lighting device of the present invention may be applied to an image display device in which a projector and a screen are integrated, such as a rear projection television.

It is operation | movement explanatory drawing which shows the example of 1 control of Embodiment 1 of this invention. It is operation | movement explanatory drawing which shows the other example of control of Embodiment 1 of this invention. It is operation | movement explanatory drawing which shows another example of control of Embodiment 1 of this invention. It is operation | movement explanatory drawing which shows the synchronous timing signal and polarity inversion timing of Embodiment 1 of this invention. It is a circuit diagram which shows the circuit structure of Embodiment 1 of this invention. It is operation | movement explanatory drawing of Embodiment 2 of this invention. It is operation | movement explanatory drawing of Embodiment 3 of this invention. It is operation | movement explanatory drawing of Embodiment 4 of this invention. It is operation | movement explanatory drawing of Embodiment 5 of this invention. It is a schematic block diagram of the image display apparatus carrying the high pressure discharge lamp lighting device of this invention. It is a schematic block diagram of the image display apparatus using a rotation color filter. It is explanatory drawing which shows the relationship between a synchronous timing signal and a lamp current.

Explanation of symbols

E DC power supply circuit 11 Step-down chopper circuit 12 Polarity inversion circuit 14 Control circuit La High pressure discharge lamp CS0 Synchronization timing signal 35c Rotating color filter

Claims (7)

A rotating color filter that time-divides a light beam output from a high-pressure discharge lamp into a plurality of colors by a plurality of color segments, an image display element that modulates a light beam that has passed through the rotating color filter with a video signal, and a rotating color filter A discharge lamp lighting device of an image display device, comprising: means for outputting a synchronization timing signal synchronized with a switching point of the color segment of the rotating color filter at least once during one rotation of
Power supply means that can control the power supplied to the high pressure discharge lamp in response to the synchronization timing signal for each color segment of the rotating color filter;
Means for receiving the synchronization timing signal and reversing the current direction of the high-pressure discharge lamp,
Even when the synchronization timing signal is input, a polarity reversal pause period that does not reverse the current direction of the high-pressure discharge lamp is inserted every predetermined time,
The polarity reversal pause period starts from the synchronization timing signal or the switching point of the color segment that has passed a predetermined number of color segments from the synchronization timing signal, and after the synchronization timing signal is input a predetermined number of times, The high-pressure discharge lamp lighting device is characterized in that the synchronization timing signal is an end point, or a color segment switching time point after a predetermined number of color segments has elapsed from the synchronization timing signal. 2. The high voltage according to claim 1, wherein a ratio of the polarity reversal pause period in which the current direction of the high pressure discharge lamp is a positive direction and the polarity reversal pause period in which the current direction of the high pressure discharge lamp is a negative direction are substantially equal. Discharge lamp lighting device. 2. The high-pressure discharge lamp according to claim 1, wherein a ratio of a polarity inversion pause period in which the current direction of the high-pressure discharge lamp is a positive direction and a polarity inversion pause period in which the current direction of the high-pressure discharge lamp is a negative direction are different. Electric light lighting device. In any one of Claims 1-3, when changing the average electric power thrown into a high pressure discharge lamp, changing the length of the polarity reversal stop period and / or the interval which inserts the polarity reversal stop period High pressure discharge lamp lighting device. In any one of Claims 1-3, when changing the control pattern of the electric power supplied to a high pressure discharge lamp for every color segment, the length of the said polarity inversion pause period and / or the said polarity inversion pause period are inserted The high pressure discharge lamp lighting device characterized by changing the interval of the high pressure discharge lamp. 6. The timing of inverting the current direction of the high-pressure discharge lamp first after the end of the polarity reversal pause period is the end of the color segment at which the power supplied to the high-pressure discharge lamp is maximum. There is a high pressure discharge lamp lighting device. An image display device comprising the high-pressure discharge lamp lighting device according to claim 1.

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