JP4853831B2 - High pressure discharge lamp lighting device and high pressure discharge lamp lighting method - Google Patents

Description

  The present invention relates to a high pressure discharge lamp lighting device and a lighting method for lighting a high pressure discharge lamp by supplying an alternating lamp current.

  High-pressure discharge lamp devices used in liquid crystal projectors and the like switch the polarity of the high-pressure discharge lamp by converting the current supplied from the DC power source into a rectangular current of 50 Hz to 1 kHz (hereinafter referred to as “reference frequency current”). It is configured to light up. Here, the high-pressure discharge lamp is a high-pressure mercury lamp (hereinafter referred to as “lamp”), in which a halogen substance, a rare gas, and mercury are enclosed, and a pair of electrodes are disposed facing each other in the arc tube.

  By the way, it is known that when the lamp as described above is continuously lit at a reference frequency current, a so-called flicker is generated in which the starting point of the discharge arc jumps on the electrode tip. This is because as the lighting time advances, a plurality of protrusions are formed at the tip of the electrode as shown in FIG. 11A, and the starting point of the discharge arc moves between the plurality of protrusions during lighting.

  In order to suppress this flicker, measures have been reported so far by applying a current having a special waveform (hereinafter referred to as “flicker suppression waveform current”) to the lamp. For example, in Patent Document 1, as a flicker suppression waveform current, one cycle of a high-frequency current is inserted between half cycles of a low-frequency rectangular wave current as a base, and the latter half of the high-frequency portion or one cycle is the reference wave portion. What is made larger than the current is disclosed (see FIGS. 3A and 3B). Then, by lighting with such a current waveform, one projection as shown in FIG. 11B is formed at the tip of the lamp electrode, and flicker is suppressed by setting the starting point of the arc at the projection. It is.

In addition to the waveforms shown in FIG. 3, various flicker suppression waveform currents have been reported. For example, Patent Document 2 discloses a method in which a pulse current is superimposed on the basis of a low-frequency rectangular wave current at the end of the half cycle (see FIG. 13A).
Patent Document 3 discloses a current waveform in which the current gradually increases from the start to the end in the half cycle based on the low-frequency rectangular wave current (FIG. 9 (FIG. 9)). a)).
Furthermore, Patent Document 4 discloses a case where the start portion of the half cycle of the rectangular wave current is high and a case where the start portion and the end portion are high (FIGS. 13B to 13F). reference).

In order to facilitate understanding of the problems in the prior art described later and the operation of the present invention, the circuit configuration and operation of an apparatus (hereinafter referred to as “conventional example”) for generating a current waveform of Patent Document 1 are described. This will be explained here.
FIG. 12 is a circuit configuration diagram of a conventional example. A full-wave rectifier circuit 10, a step-down chopper circuit 20 that controls a DC voltage of the full-wave rectifier circuit 10 to a predetermined lamp power by a PWM (pulse width modulation) control circuit, and a step-down chopper. A full bridge circuit 40 for converting the DC output voltage of the circuit 20 into a low frequency AC rectangular wave voltage and applying it to the lamp 60, an igniter circuit 50 for applying a high voltage pulse voltage to the lamp at the time of starting the lamp, and lamp power And a control circuit 30 for performing constant lamp power control and constant lamp current control.

  The step-down chopper circuit 20 that operates by receiving the voltage of the full-wave rectifier circuit 10 includes a transistor 21 driven by a PWM control circuit 37, a diode 22, a choke coil 23, and a smoothing capacitor 24, and is supplied from the full-wave rectifier circuit 10. Predetermined lamp power control or lamp current control is performed on the direct current voltage.

  The control circuit 30 multiplies the divided voltage by the resistors 31 and 32 that divide and detect the lamp voltage connected in parallel with the lamp 60 and the voltage of the resistor 33 that is connected in series with the lamp 60 and detects the lamp current. Then, the multiplier 34 for calculating the lamp power, the error amplifier 35 for comparing the output terminal of the multiplier 34 with the voltage of the DC power supply 38, and the output of the error amplifier 35 are input, and the transistor 21 of the step-down chopper circuit 20 is driven. The PWM control circuit 37 outputs a pulse. The DC power supply 38 and the bridge control circuit 45 are connected to the central control unit 39, and the output voltage of the DC power supply 38 is high / low (accordingly, the on-duty ratio of the transistor 21) and the transistors 41 to 44 using the same clock signal. ON / OFF is periodically controlled.

  The PWM control circuit 37 generates a drive pulse with a duty ratio corresponding to the output of the error amplifier 35 to drive the transistor 21 of the step-down chopper circuit 20. As a result, constant lamp power control is performed so that the lamp power is constant when the lamp voltage is greater than or equal to a predetermined value, and constant lamp current control is performed so that the lamp current is constant when the lamp voltage is less than the predetermined value. It has become.

3C and 3D, on / off of the transistors 41 to 44 of the full bridge circuit 40 and the transistor 21 of the step-down chopper 20 for forming the current waveforms of FIGS. 3A and 3B, respectively. The timing chart about the on-duty ratio and lamp current is shown.
Lamp current waveform applied as shown for a period of one cycle of the high frequency current and (T _HF) consists repetition period of the low frequency current half-cycle, FIG. 3 (a) and (c) in the period T _HF On the other hand, the current value of the latter half cycle is higher than the current value of the low frequency current period, while in FIGS. 3B and _3D , the current value of one cycle of the period _THF is the period of the low frequency current. The current value is higher.

The frequency of one cycle period of _{t 1} from _{t 0} in FIG. 3 (a) and (b) is about 50Hz～1kHz. In FIG. 3, for the sake of clarity, the width of the high-frequency portion is larger than that of the low-frequency portion, but the period width of the high-frequency portion: the period width of the low-frequency portion is 1: It is about 20 to 1: 4.
JP 2006-202775 A Japanese National Patent Publication No. 10-501919 Japanese Patent Laid-Open No. 2003-243195 Japanese Patent Laid-Open No. 2004-296427

  If the above technique is used, it appears that flicker is suitably suppressed by forming protrusions at the tip of the lamp electrode by various flicker suppression waveform currents. However, it has been found that continuing such a current may cause the following problems with respect to the lamp and the lighting circuit.

The problem with the lamp is related to overgrowth of protrusions. Here, protrusions are formed on the electrodes, and the principle of growth of the protrusions is not necessarily clear, but is assumed as follows.
In general, high-pressure mercury lamps for liquid crystal projectors contain a halogen substance in addition to mercury as an enclosure. When the halogen cycle of this halogen substance is performed, tungsten is evaporated and forms a tungsten compound when combined with halogen or the like present in the arc tube. This tungsten compound diffuses from the vicinity of the tube wall to the vicinity of the tip of the electrode by convection or the like, and is decomposed into tungsten atoms at a high temperature portion. Tungsten atoms become cations when ionized in the arc. Both electrodes that are lit with alternating current repeat the anode and cathode at each lighting frequency, but when this cathode is operating, the cations in the arc are attracted to the cathode side by the electric field, and are deposited at the tips of both electrodes. It is believed that it forms a protrusion.

As a result, the tip of the electrode grows in a protruding shape, so that the arc length may be shortened and the lamp voltage may gradually decrease. However, when the protrusion at the tip of the electrode grows and the lamp voltage becomes equal to or lower than a predetermined value, the rated lamp power is not supplied even if the lamp current is flown to the maximum within the rated current range. For this reason, there is a case where the lamp electrode temperature is lowered, and further, a projection of the electrode grows, resulting in a vicious circle in which the lamp voltage is further lowered. If the lamp power is further reduced by lowering the lamp voltage, in addition to the decrease in light output, the tungsten halogen cycle in the arc tube cannot be sufficiently performed, the blackening in the arc tube of the lamp proceeds, and the lamp becomes short. The problem of end of life occurs.
Regarding Patent Documents 1 to 4, although the mechanism and effect of protrusion formation / growth by each flicker suppression waveform current are considered to be different from each other, as described above, as a result of continuing to apply some flicker suppression waveform current, the protrusions It has been found that it grows more than necessary.

The problem with the lighting circuit is related to heat generation (loss) and noise. For example, considering the circuit configuration of FIG. 12, the igniter circuit 50 is provided for the purpose of dielectric breakdown between the lamp electrodes when starting the lamp. The secondary winding of the pulse transformer that constitutes the igniter circuit 50 is connected in series to the lamp in spite of having no function in the lighting state after starting the lamp. Unnecessary heat loss and noise occur in the secondary winding. Since this heat loss is proportional to the square of the current value, when outputting the flicker suppression waveform current of Patent Documents 1 to 4 in which the current waveform has a high current value portion, compared to the case of outputting the reference waveform current. Thus, the heat loss in the secondary winding due to the lamp current during lighting increases. As for noise, in particular, in the case of the current waveform of Patent Document 1 in which a high-frequency current is inserted, the number of inversions is increased as compared with the case of the reference waveform current. Therefore, the pulse transformer (specifically, the core) is caused by a sudden change in magnetic flux. Vibrates and noise increases.
The generated heat loss can be suppressed by increasing the winding wire diameter, and the generation of sound can be suppressed to some extent by bonding the core and bobbin (for example, impregnating with varnish including the winding). However, as a result, the apparatus becomes larger and heavier and the cost increases, which is not a suitable measure.

  A first aspect of the present invention includes an AC power supply circuit that applies an AC lamp current to a high-pressure discharge lamp, and a control circuit that controls the AC power supply circuit. The control circuit has a rectangular shape with an AC lamp current of 50 Hz to 1 kHz. In a high-pressure discharge lamp lighting device capable of outputting a reference waveform current that is a wave current and a flicker suppression waveform current obtained by modifying the reference waveform current to an AC power supply circuit, the control circuit suppresses the flicker of the AC lamp current at a predetermined timing. A high-pressure discharge lamp lighting device comprising switching means for switching from a waveform current to a reference waveform current, and a determination means for monitoring a parameter relating to a lighting state of the high-pressure discharge lamp and determining a predetermined timing based on the parameter.

Here, a current having a frequency higher than the low frequency current (hereinafter referred to as “high frequency current”) immediately before a half cycle of a rectangular wave current (hereinafter referred to as “low frequency current”) having a flicker suppression waveform current of 50 Hz to 1 kHz. The current waveform is applied for one or more cycles, and the current value of only the latter half of one cycle of the high-frequency current or the whole cycle is higher than the current value of the low-frequency current.
Further, at the time of switching from the flicker suppressing waveform current to the reference waveform current, only the latter half cycle of one cycle of the high-frequency current or the duration of the current of all the cycles is decreased stepwise or continuously. I made it.

The parameter may be an elapsed time from the start of lighting of the high-pressure discharge lamp, and the predetermined timing may be a time point when the elapsed time reaches a predetermined time of 1.5 minutes or more and 20 minutes or less. Further, the parameter may be the lamp voltage of the high-pressure discharge lamp, and the predetermined timing may be a time point when the lamp voltage becomes equal to or lower than the predetermined voltage. Further, the parameter may be a differential value with respect to the time of the lamp voltage of the high-pressure discharge lamp, and the predetermined timing may be a point in time when the differential value becomes equal to or less than a predetermined value.
Further, at the time of switching from the flicker suppression waveform current to the reference waveform current, the AC lamp current is supplemented with at least one complementary waveform that complements the difference in the current waveform between the flicker suppression waveform current and the reference waveform current from the flicker suppression waveform current. Switch to reference waveform current via current.

  The second aspect of the present invention is a light source device comprising the high pressure discharge lamp lighting device, the high pressure discharge lamp, the reflector to which the high pressure discharge lamp is attached, and a housing containing at least the high pressure discharge lamp lighting device of the first aspect. is there.

  A third aspect of the present invention includes an AC power supply circuit that applies an AC lamp current to a high-pressure discharge lamp, and a control circuit that controls the AC power supply circuit. The control circuit has a rectangular shape with an AC lamp current of 50 Hz to 1 kHz. A method for lighting a high pressure discharge lamp in a high pressure discharge lamp lighting device capable of outputting a reference waveform current which is a wave current and a flicker suppression waveform current obtained by modifying the reference waveform current to an AC power supply circuit, wherein (A) start of lighting Thereafter, the control circuit outputs a flicker suppression waveform current to the AC power supply circuit, (B) a step of monitoring a parameter relating to a lighting state of the high pressure discharge lamp by the control circuit, and (C) a control based on the monitored parameter. The circuit switches the output current of the AC power supply circuit from the flicker suppression waveform current to the reference waveform current, and (D) control Road is lit method comprising the step of maintaining the output of the reference waveform current into AC power supply circuit.

  Here, a current having a frequency higher than the low frequency current (hereinafter referred to as “high frequency current”) immediately before a half cycle of a rectangular wave current (hereinafter referred to as “low frequency current”) having a flicker suppression waveform current of 50 Hz to 1 kHz. The current waveform is applied for one or more cycles, and the current value of only the latter half of one cycle of the high-frequency current or the whole cycle is higher than the current value of the low-frequency current. In addition, the above parameter is the elapsed time from the start of lighting of the high-pressure discharge lamp, and the predetermined timing is the time when the elapsed time reaches a predetermined time of 1.5 minutes or more and 20 minutes or less.

  According to the present invention, an electrode protrusion is formed by supplying a flicker suppression waveform current until a predetermined time from when the lamp is turned on, or until a preset voltage is detected after a predetermined time has elapsed. Thus, the starting point of the arc is determined, and the arc jump (that is, flicker) is suppressed. After the arc bright spot is created, flicker does not occur even if the lamp is turned on at the reference frequency current. Further, a stable light output can be supplied without the protrusion at the electrode tip continuing to grow. Furthermore, for the lighting device, after shifting to the output of the reference waveform current, there is no part that temporarily increases the lamp current value in the waveform, so the heat loss is small and the sound is quiet when the lamp is steadily lit. .

As described above, the concept of the present invention is to obtain the above effect by lighting using a flicker suppression waveform current from the start of lighting to a predetermined timing, and thereafter lighting using a reference waveform current. .
The flowchart is shown in FIG. First, when the power source 1 is turned on, start control is performed in step 101, and the lamp starts to light. In step 102, the lamp is turned on by the flicker suppression waveform current. In step 103, any parameter related to the lamp is monitored, and it is determined whether or not the switching timing has been reached based on the parameter. If the switching timing has not been reached, step 102 is continued, and if it has reached, the process proceeds to step 103. In step 103, the lamp current is switched from the flicker suppression current to the reference waveform current, and in step 104, lighting with the reference waveform current is continued. In the following examples, the reference waveform current is 50 Hz to 1 kHz.

Example 1.
FIG. 2 is a diagram showing a first embodiment of the present invention. Portions similar to those of the conventional example shown in FIG. The difference from FIG. 12 is that a switching means 301 and a determination means (timer) 302 in the control circuit 30 are provided. It should be noted that all or some of the elements in the control circuit 30 may be taken into the microcomputer, or may be configured by independent circuits.

When lighting is started, lighting is started with the flicker suppression waveform current shown in FIG. The waveform of each part in this case is as described above with reference to FIGS. 3 (c) and 3 (d). In this embodiment, the flicker suppression waveform current is shown in which one cycle of the high frequency portion is inserted between the low frequency portions, but a plurality of cycles may be inserted in this high frequency portion.
Then, the timer 302 counts the elapsed time from the start of lighting.

Here, regarding the relationship between the elapsed time and the lamp voltage, on the premise that the shape of the protrusion at the tip of the electrode hardly changes (no matter what lamp current waveform is applied), as shown in FIG. After ts, it shifts to stable lighting. The value of ts varies in the range of 1.5 to 20 minutes depending on the rated power of the lamp, but if the rated power is the same, the time is not so different. For example, in the case of a lamp with a rated power of 170 W, ts is about 10 minutes.
On the other hand, on the premise that there is formation or growth of protrusions, if lighting continues with a flicker suppressing waveform current as shown in FIG. 3A or FIG. 3B, the protrusions continue to grow as shown in FIG. As a result, the lamp voltage may drop.

Therefore, as shown in FIG. 5C, the timer 302 counts tx (for example, 10 minutes when the rated power is 170 W), which is the time near ts, and the switching circuit 301 displays the lamp current at time tx. 4 is switched to the reference waveform current. That is, as the circuit operation, the voltage of the DC power supply 38 is made constant, and the operation shifts to an operation of turning on / off the transistors (41, 44) and (42, 43) at the reference frequency.
In FIG. 5C, ts <tx is set, but ts is a slightly different value depending on lamp lighting conditions and the like, and as a result, tx ≦ ts may be satisfied.

  As a result, even if the lamp is turned on as shown in FIG. 5B when it is continuously lit with the flicker suppression waveform current, the change in the lamp voltage can be made as shown in FIG. 5C. It should be noted that a lamp that exhibits the characteristics as shown in FIG. 5A regardless of the lamp current waveform, as shown in FIG. 5A, whether or not the above switching is performed. A simple curve is obtained.

  In the same device, the frequency of the low frequency portion and the reference waveform current included in the flicker suppression waveform current may be the same or different. That is, the reference waveform current in the former case (identical) is a waveform obtained by extracting the high frequency portion from the flicker suppression waveform current and connecting only the low frequency portion.

In order to confirm the effect of this embodiment, measurement and comparison of changes in lamp voltage, noise level of the high pressure discharge lamp lighting device, and winding temperature of the igniter circuit were performed using devices A, B and C having different specifications. .
The device A is a device that continues to output the flicker suppression waveform current, the device B is a device that continues to output only the reference waveform current, and the device C is the flicker suppression waveform current at the timing of 10 minutes from the start of lighting as in this embodiment. Is a device that switches the output from the current to the reference waveform current.

  In the apparatuses A and C, the flicker suppression waveform current is a low frequency rectangular wave of 105 Hz and a high frequency rectangular wave of 1.19 kHz inserted in every half cycle. The current value is half the frequency of the first half cycle and 1.25 times the current value of the low frequency part. In the devices B and C, the reference waveform current is a 200 Hz rectangular wave. In any of the devices A, B, and C, the output lamp power was set to 170 W.

１０分経過後であれば基準波形電流を印加するようにしてもそれまでに形成された突起を起点としてアークの位置が定まりフリッカは起こらず、また、表から分かるように、その突起はそれ以上成長しないことが確認された。 Table 1 shows the measurement result of the change in lamp voltage when the apparatus C is used.
Table 1

After 10 minutes, even if the reference waveform current is applied, the position of the arc is fixed starting from the protrusion formed so far, and flicker does not occur. It was confirmed that it did not grow.

表から分かるように、全ての測定周波数帯において装置Ｂの騒音レベルが装置Ａの騒音レベルよりも低いことが確認された。即ち、点灯開始後の所定の時間経過後（例えば１０分後）には騒音の低い状態で装置を使用できるということを意味するものである。 Table 2 shows the measurement results of the noise level of the device.
Table 2

As can be seen from the table, it was confirmed that the noise level of the device B was lower than the noise level of the device A in all measurement frequency bands. In other words, it means that the device can be used in a low noise state after a predetermined time has elapsed after the start of lighting (for example, after 10 minutes).

表から分かるように、装置Ｂの場合は装置Ａの場合よりも絶対温度として９度も低いことが確認された。また、周囲温度との差分である温度上昇については装置Ａが４３．２ｄｅｇ、装置Ｂが３４．２ｄｅｇであり、温度上昇（即ち、損失）が約２０％も低減されたことが分かる。 Table 3 shows the measurement results of the winding temperature of the igniter circuit.
Table 3

As can be seen from the table, the device B was confirmed to be 9 degrees lower in absolute temperature than the device A. Further, regarding the temperature rise, which is a difference from the ambient temperature, it can be seen that apparatus A is 43.2 deg and apparatus B is 34.2 deg, and the temperature rise (ie, loss) is reduced by about 20%.

As described above, according to the present embodiment, it is possible to obtain a lighting device that is capable of preventing flicker and maintaining the distance between the lamp electrodes and is low in noise and loss.
Further, since the switching operation is performed based only on the elapsed time from the start of lighting, no complicated control is required, and unnecessary malfunctions are not induced. Further, although the switching timing is 10 minutes after the start of lighting, an appropriate time may be used in the range of 1.5 minutes to 20 minutes after considering the lamp rating and the like.

Example 2
In the first embodiment, the determination material for the switching timing is based on the elapsed time from the start of lighting. In this embodiment, the determination is based on the lamp voltage.
FIG. 6 is a circuit diagram showing this embodiment. The difference from the first embodiment is that a lamp voltage determination circuit 303 is provided as a determining means instead of the timer. The lamp voltage determination circuit 303 takes in the lamp voltage _VL detected by the voltage dividing resistors 31 and 32 and determines the switching timing.

The determination based on the lamp voltage may be based on the lamp voltage value or may be based on a differential value of the lamp voltage with respect to time.
For example, (1) even if the switching means 301 is operated to switch from the flicker suppression waveform current to the reference waveform current when the lamp voltage falls below a predetermined value (for example, 60 V) after the lamp voltage once falls within the appropriate lamp voltage range. (2) It may be switched when the lamp voltage becomes a predetermined value or less after a predetermined time has elapsed since the start of lighting, or (3) when the lamp voltage is still low after the predetermined time has elapsed. Switching may be performed. In the above cases (2) and (3), it is necessary to use a timer.

  As an example of using the determination based on the lamp voltage differential value, (1) it is determined that the lighting state of the lamp has reached a stable state when the lamp voltage differential value becomes 0, and the flicker suppression waveform is operated by operating the switching means 301. The current may be switched to the reference waveform current. Further, (2) even if the stable lighting is not completely reached, it is predicted that the stable lighting will be reached when the rise of the lamp voltage becomes moderate, that is, when the differential value becomes a predetermined positive value or less. Then, switching may be performed. Further, (3) switching may be performed by detecting that the lamp voltage drop is steep when the differential value becomes equal to or less than a predetermined negative value. In the case of (2), the application time of the flicker suppression waveform current can be minimized, and as a result, the heat loss and the noise duration can be minimized. In the case of the above (3), it is desirable to perform switching when a drop in the lamp voltage is not detected by an appropriate time by using a timer or the like.

  Note that the above-described determination result based on the lamp voltage value, the determination result based on the differential value of the lamp voltage, and the determination result based on the elapsed time from the start of lighting are switched by taking their logical sum (OR) or logical product (AND). The switching timing in 301 may be determined carefully or flexibly.

  As described above, according to this embodiment, it is possible to achieve both prevention of flicker and maintenance of the distance between the lamp electrodes. In addition, after shifting to lighting with a reference waveform current, the lighting device can be used with low loss and low noise.

Example 3
In the first and second embodiments, the switching unit 301 instantly switches from the flicker suppression waveform current to the reference waveform current. However, in the present embodiment, the switching unit 301 performs the switching in a multistage or continuous manner. Indicates. That is, at the time of switching in step 103 of FIG. 1, the flicker suppression waveform current is passed through at least one complementary waveform current that complements the difference in the current waveform between the flicker suppression waveform current and the reference waveform current, Transition to the reference waveform current.

FIGS. 7 and 8 show an example in which the current waveform of FIG. 3A is used as the flicker suppression waveform current, for example.
In FIG. 7, the period width of the high frequency portion (T _HF ) of the flicker suppression waveform current is gradually reduced. At the time of switching, the period width of the high frequency part (T _HF ) is changed from the waveform of FIG. 7A via the waveforms of (b) and (c), that is, without changing the period width of the low frequency part. Decrease / disappear and reach the waveform of (d).
Further, FIG. 8 gradually reduces the period width of the second half (T _half ) of the high frequency portion of the flicker suppression waveform current. At the time of switching, the period (T _half) is changed from the waveform of FIG. 8A through the waveforms of (b) and (c), that is, without changing the entire period including the low frequency portion and the high frequency portion. ) Is reduced or eliminated, and the waveform of (d) is reached.

  7 and 8, it is desirable that the output value of the step-down chopper circuit 20, that is, the voltage value of the DC power supply 38 (change in the on-duty ratio of the transistor 21 corresponding thereto) be gradually flattened. . In the embodiment, the flicker suppression waveform current is one in which a high frequency current is inserted between low frequency currents, but a plurality of cycles may be inserted in this high frequency current. For a waveform in which the pulse current is superimposed on the latter half of the low frequency current as in Patent Document 2, the superimposed pulse current may be gradually decreased.

FIG. 9 shows an example in which a waveform in which the current value at the end is larger than the current value at the start of the low-frequency rectangular wave is used as the flicker suppressing waveform current. At the start of lighting, lighting is started with the waveform of (a), and thereafter, after going through (b) and going to (c), the slope of the waveform is gradually flattened without changing the effective current value.
7-9, the change in the lamp current waveform may be stepwise or continuous.

  In this way, by changing from the flicker suppression waveform current to the reference waveform current via the complementary waveform current, the change in the lamp current waveform at the time of waveform switching is prevented from visually giving the user a sense of incongruity. it can.

Example 4
In the first to third embodiments, the high pressure discharge lamp lighting device has been shown which achieves both prevention of flicker and maintenance of the distance between the lamp electrodes, and low noise and low loss, but a light source device as an application using the high pressure discharge lamp lighting device. Is shown in FIG.
In FIG. 10, 71 is the high pressure discharge lamp lighting device described above, 72 is a reflector to which the lamp 60 is attached, and 73 is a housing containing the high pressure discharge lamp lighting device 71, the lamp 60 and the reflector 72 as necessary. . In addition, the figure is a schematic illustration of the embodiment, and the dimensions, arrangement, and the like are not as illustrated. In addition, a projector can be configured by appropriately arranging a video system member or the like (not shown) in the housing 73.

  As described above, the high pressure discharge lamp lighting device with built-in low noise and low loss that achieves both prevention of flicker and maintenance of the distance between the lamp electrodes is built in, so that a light source device with improved optical characteristics and high reliability is obtained. be able to. That is, a suitable state of the lamp is established at a predetermined time after the start of lighting, and thereafter, the light source device can be used with low noise and energy saving while maintaining the state. In particular, when the lighting device of Example 1 is built in, the time of 10 minutes from the start of lighting is a time period during which the user or viewer confirms the operating state of the projector or selects the content to be displayed. Equivalent to. Therefore, when the viewer is actually concentrated on the content, noise is reduced and a good viewing state can be obtained. In this sense, a configuration in which the current waveform is switched within 1.5 to 20 minutes, particularly about 10 minutes after the start of lighting can be said to be a useful aspect in the practice of the present invention.

In addition, although the said Example was shown as the most suitable example of this invention, the following is noted in connection with it.
(1) The “rectangular wave” as the low-frequency current in this embodiment includes a waveform that is not strictly a perfect rectangular wave. For example, a waveform in which a sine wave of one cycle or more is superimposed on a complete rectangular wave for the purpose other than flicker suppression, and the current value at the start and end of a rectangular wave half cycle are slightly different. In addition, a waveform having a slight unevenness in the middle of a half cycle is also included. Therefore, the reference waveform current is intended to include such a waveform.
(2) Although a rectangular wave is used for the high-frequency current in the embodiment, it may be a sine wave, a triangular wave, a sawtooth wave, an exponential wave, or a combination thereof, and the problem is the peak value and the period width. .
(3) Although the embodiment has been described using a specific flicker suppressing waveform current, the present invention includes the types of waveforms shown in FIGS. 13A to 13F as the flicker suppressing waveform current.
(4) In the embodiment, the flicker suppression waveform current is applied from the start of lighting, but the flicker suppression waveform current is in a transient discharge state (for example, a half-wave discharge state) for several seconds to several minutes immediately after starting. The case where a current other than the above is applied is also included in the scope of the present invention.
(5) In the embodiment, the switching from the flicker suppression waveform current to the reference waveform current is performed once. However, those skilled in the art will perform the second and subsequent switching for another purpose than the present invention. It should be understood that and can be added using and / or other controls.
(6) In the embodiment, the circuit configuration capable of constant current control or constant power control is shown as the control circuit 30, but the inversion control of the transistors 41 to 44 of the full bridge circuit 40 and the transistor 21 of the step-down chopper circuit 20 are performed. As long as the duty ratio control can be performed (as a result, each waveform described above can be output), the configuration in the control circuit is not limited to the illustrated one.

  The present invention is mainly used in light source devices such as projectors, projection TVs, and projectors.

It is a flowchart which shows the lighting method of this invention. It is a figure which shows the 1st Example of this invention. It is a figure explaining the 1st Example of this invention. It is a figure explaining the 1st Example of this invention. It is a figure explaining the 1st Example of this invention. It is a figure which shows the 2nd Example of this invention. It is a figure which shows the 3rd Example of this invention. It is a figure which shows the 3rd Example of this invention. It is a figure which shows the 3rd Example of this invention. It is a figure which shows the 4th Example of this invention. It is a figure which shows the electrode of a lamp | ramp. It is a figure which shows a prior art example. It is a figure explaining a prior art example.

Explanation of symbols

1: AC power supply 10: Full wave rectifier circuit 11: Diode 12: Capacitor 20: Step-down chopper circuit 21: Transistor 22: Diode 23: Choke coil 24: Capacitor 30: Control circuits 31, 32, 33: Resistor 34: Multiplier 35 : Error amplifier 36: Integration circuit 37: PWM control circuit 38: DC power supply 39: Central control unit 301. Switching means 302. Timer (determination means)
303. Lamp voltage determination circuit (determination means)
40: full bridge circuit 41, 42, 43, 44: transistor 45: bridge control circuit 50: igniter circuit 51: igniter control circuit 60: high pressure discharge lamp 71. High pressure discharge lamp lighting device 72. Reflector 73. Enclosure

Claims (7)

An AC power supply circuit that applies an AC lamp current to a high-pressure discharge lamp, and a control circuit that controls the AC power supply circuit, and the control circuit is a rectangular waveform current of 50 Hz to 1 kHz as the AC lamp current In the high pressure discharge lamp lighting device capable of causing the AC power supply circuit to output a flicker suppression waveform current obtained by modifying the current and the reference waveform current,
The control circuit comprises:
Switching means for switching the AC lamp current from the flicker suppression waveform current to the reference waveform current at a predetermined timing; and
Determination means for monitoring a parameter relating to a lighting state of the high-pressure discharge lamp and determining the predetermined timing based on the parameter
With
A current having a frequency higher than the low frequency current (hereinafter referred to as “high frequency current”) is 1 immediately before a half cycle of a rectangular wave current (hereinafter referred to as “low frequency current”) having a flicker suppression waveform current of 50 Hz to 1 kHz. A current waveform applied for more than one cycle, wherein the current value of only the latter half of one cycle of the high-frequency current or the current value of the whole cycle is higher than the current value of the low-frequency current,
The high-pressure discharge lamp lighting device, wherein the parameter is an elapsed time from the start of lighting of the high-pressure discharge lamp, and the predetermined timing is a time when the elapsed time reaches a predetermined time of 1.5 minutes or more and 20 minutes or less.
An AC power supply circuit that applies an AC lamp current to a high-pressure discharge lamp, and a control circuit that controls the AC power supply circuit, and the control circuit is a rectangular waveform current of 50 Hz to 1 kHz as the AC lamp current In the high pressure discharge lamp lighting device capable of causing the AC power supply circuit to output a flicker suppression waveform current obtained by modifying the current and the reference waveform current,
The control circuit comprises:
Switching means for switching the AC lamp current from the flicker suppression waveform current to the reference waveform current at a predetermined timing; and
Determination means for monitoring a parameter relating to a lighting state of the high-pressure discharge lamp and determining the predetermined timing based on the parameter
With
A current having a frequency higher than the low frequency current (hereinafter referred to as “high frequency current”) is 1 immediately before a half cycle of a rectangular wave current (hereinafter referred to as “low frequency current”) having a flicker suppression waveform current of 50 Hz to 1 kHz. A current waveform applied for more than one cycle, wherein the current value of only the latter half of one cycle of the high-frequency current or the current value of the whole cycle is higher than the current value of the low-frequency current,
The high pressure discharge lamp lighting device, wherein the parameter is a lamp voltage of the high pressure discharge lamp, and the predetermined timing is when the lamp voltage becomes equal to or lower than a predetermined voltage.
An AC power supply circuit that applies an AC lamp current to a high-pressure discharge lamp, and a control circuit that controls the AC power supply circuit, and the control circuit is a rectangular waveform current of 50 Hz to 1 kHz as the AC lamp current In the high pressure discharge lamp lighting device capable of causing the AC power supply circuit to output a flicker suppression waveform current obtained by modifying the current and the reference waveform current,
The control circuit comprises:
Switching means for switching the AC lamp current from the flicker suppression waveform current to the reference waveform current at a predetermined timing; and
Determination means for monitoring a parameter relating to a lighting state of the high-pressure discharge lamp and determining the predetermined timing based on the parameter
With
A current having a frequency higher than the low frequency current (hereinafter referred to as “high frequency current”) is 1 immediately before a half cycle of a rectangular wave current (hereinafter referred to as “low frequency current”) having a flicker suppression waveform current of 50 Hz to 1 kHz. A current waveform applied for more than one cycle, wherein the current value of only the latter half of one cycle of the high-frequency current or the current value of the whole cycle is higher than the current value of the low-frequency current,
The high-pressure discharge lamp lighting device, wherein the parameter is a differential value with respect to time of the lamp voltage of the high-pressure discharge lamp, and the predetermined timing is when the differential value becomes equal to or less than a predetermined value.
In the high pressure discharge lamp lighting device according to claim 1, 3 any one, when from the flicker suppression waveform current switching to the reference waveform current, the alternating lamp current from the flicker suppression waveform current, the flicker A high pressure discharge lamp lighting device that is switched to the reference waveform current via at least one complementary waveform current that complements the difference in current waveform between the suppressed waveform current and the reference waveform current.
4. The high-pressure discharge lamp lighting device according to claim 1 , wherein, when switching from the flicker-suppressing waveform current to the reference waveform current, only the latter half cycle of one cycle of the high-frequency current is performed. Or the high pressure discharge lamp lighting device controlled so that the period width of the electric current of one cycle may be reduced stepwise or continuously.
High-pressure discharge lamp lighting device according to one Section 5 claim 1, the high pressure discharge lamp, the light source apparatus comprising a housing which encloses the reflector the high pressure discharge lamp is attached, and at least the high-pressure discharge lamp lighting device.
An AC power supply circuit that applies an AC lamp current to a high-pressure discharge lamp, and a control circuit that controls the AC power supply circuit, and the control circuit is a rectangular waveform current of 50 Hz to 1 kHz as the AC lamp current A method for lighting a high-pressure discharge lamp in a high-pressure discharge lamp lighting device capable of outputting a current and a flicker-suppressed waveform current obtained by modifying the reference waveform current to the AC power supply circuit,
(A) After starting lighting, the control circuit outputs the flicker suppression waveform current to the AC power supply circuit;
(B) monitoring a parameter relating to a lighting state of the high-pressure discharge lamp in the control circuit;
(C) the control circuit switching the output current of the AC power supply circuit from the flicker suppression waveform current to the reference waveform current based on the monitored parameter;
(D) causing the control circuit to maintain the output of the reference waveform current in the AC power supply circuit
Consists of
A current having a frequency higher than the low frequency current (hereinafter referred to as “high frequency current”) is 1 immediately before a half cycle of a rectangular wave current (hereinafter referred to as “low frequency current”) having a flicker suppression waveform current of 50 Hz to 1 kHz. A current waveform applied for more than one cycle, wherein the current value of only the latter half of one cycle of the high-frequency current or the current value of the whole cycle is higher than the current value of the low-frequency current,
The lighting method, wherein the parameter is an elapsed time from the start of lighting of the high-pressure discharge lamp, and the predetermined timing is a time when the elapsed time reaches a predetermined time of 1.5 minutes or more and 20 minutes or less.

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