JP2006286228A - Discharge lamp lighting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting device where light of a discharge lamp is not gradually changed even if the discharge lamp is started with light modulation. <P>SOLUTION: This discharge lamp lighting device is provided with: an inverter device 2 for converting D.C. power 1 to high-frequency power by a drive signal of a drive circuit 21 to supply it to a lamp 3 connected through a coupling capacitor 6 for lighting the lamp; a lighting detection circuit 8 for detecting the lighting of the lamp 3; and a frequency control circuit 9 for controlling the frequency of each drive signal in response to a preheating mode and a starting mode and for controlling the frequency of the drive signal so as to instantly move to a preset light modulation mode when the lighting of the discharge lamp is detected by the lighting detection circuit 8 in the starting mode. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device that suppresses a change in light after starting a discharge lamp that occurs when the discharge lamp is dimmed.

  As a conventional discharge lamp lighting device, for example, an inverter that turns on and off a switching element to convert a DC voltage into high-frequency power, a discharge lamp that is connected to the inverter via a coupling capacitor and is lit with high-frequency power, A protection circuit having a voltage detection circuit for detecting a voltage generated in the coupling capacitor, a feedback circuit for detecting a voltage for controlling the IV control integrated circuit so that the high frequency power becomes equal to the reference value, and an output from the voltage detection circuit And a dimming start control circuit which masks the feedback circuit so as not to operate until immediately before the discharge lamp starts based on the control signal, and releases the mask and starts dimming when the discharge lamp starts. Yes (see, for example, Patent Document 1).

  Further, for example, an inverter device that converts DC power into high-frequency power, a control circuit that controls the inverter device, an LC series circuit connected to the inverter device, and a discharge lamp that constitutes a load circuit together with the LC series circuit, Means for preheating the electrode of the discharge lamp when starting and lighting the discharge lamp, means for starting discharge by applying a high pressure to the discharge lamp, and an abnormality detection protection means for protecting the inverter when the discharge lamp is abnormal The discharge lamp is started and started by changing the output frequency of the inverter, and the frequency change interval during the discharge start operation is made longer than the frequency change time interval during discharge lamp preheating. There is a discharge lamp lighting device provided with a means (for example, see Patent Document 2).

JP 2001-284091 A (page 4-6, FIG. 1) JP-A-6-251888 (page 6-7, FIG. 6)

  In the prior art of Patent Document 1 described above, the start of the discharge lamp is detected from the voltage generated in the coupling capacitor, and after the lighting is detected, the frequency at the lighting is changed stepwise to shift to the frequency required for dimming lighting. Therefore, it has been confirmed that the light from the discharge lamp changes step by step. Moreover, since the prior art of patent document 2 changes in a stepwise manner from the frequency at the time of a start to the frequency required for dimming lighting after a start mode, it seems that the light of a discharge lamp changes in steps like the above. It was confirmed. Some users feel uncomfortable with the stepwise light change of the discharge lamp that is confirmed at the time of dimming start, and some of them want a discharge lamp lighting device that does not change the light of the discharge lamp.

  DISCLOSURE OF THE INVENTION The present invention has been made to solve the above-described problems. A discharge lamp in which the light of the discharge lamp does not change stepwise even when the discharge lamp is dimmed or when all light is started. An object is to provide a lighting device.

  A discharge lamp lighting device according to the present invention includes an inverter device that converts a voltage of a DC power source into high-frequency power by a drive signal of a drive circuit, and supplies the discharge lamp connected via a coupling capacitor for lighting, and a discharge lamp The lighting detection means for detecting the lighting of the lamp, and the frequency of the drive signal is controlled in accordance with the preheating mode and the starting mode, respectively, and when the lighting of the discharge lamp is detected by the lighting detecting means in the starting mode, a preset dimming Frequency control means for controlling the frequency of the drive signal so as to immediately shift to the mode.

  In the present invention, when the lighting of the discharge lamp is detected by the lighting detection means in the start mode, the frequency of the drive signal is controlled so as to immediately shift to the preset dimming mode. The step-by-step light change of the discharge lamp that is confirmed when the dimming is started is eliminated, and the discomfort due to the step-by-step light change can be eliminated.

Embodiment 1 FIG.
FIG. 1 is a circuit block diagram showing a schematic configuration of a discharge lamp lighting device according to Embodiment 1 of the present invention.
The discharge lamp lighting device according to the present embodiment is, for example, a half-bridge lighting circuit, and is alternately turned on / off by a DC power source 1 and a drive signal (pulse signal) of the drive circuit 21 and the drive circuit 21. Inverter device 2 composed of a pair of switching elements 22 and 23 for converting the power into high-frequency power, a discharge lamp 3 (hereinafter referred to as “lamp”) provided on the output side of the inverter device 2, and a high-frequency current flowing through the lamp 3 Is connected to both ends of the lamp 3 and the starting capacitor 5 which is connected to both ends of the lamp 3 to form a series resonance circuit, and the switching elements 22 and 23 are alternately turned on / off based on charging / discharging. The coupling capacitor 6 that repeats the above, the lighting detection circuit 8 to which the illuminance sensor 7 is connected, and the frequency for controlling the frequency of the drive signal through the drive circuit 21. Several control circuit 9, and a timer circuit 10 for counting the preheating period t1 and the starting period of the lamp 3 a preset t2 (approximately 0.5 seconds) sequentially.

  The illuminance sensor 7 described above detects the illuminance due to the lighting of the lamp 3, generates a voltage based on the detected illuminance, and outputs the voltage to the lighting detection circuit 8. The lighting detection circuit 8 has a voltage set for the illuminance when the lamp 3 is lit at start-up as a lighting determination value, and outputs a lighting detection signal when the voltage from the illuminance sensor 7 reaches the lighting determination value. Output to the frequency control circuit 9. The frequency control circuit 9 has a preheating mode frequency f1, a start mode frequency f2, an all-light mode frequency f3, and a dimming mode frequency f4 in advance, and when a lighting detection signal is input within the start period t2. The drive circuit 21 is controlled so that the frequency f2 in the start mode shifts to the frequency f4 in the dimming mode, and a drive signal of this frequency f4 is output. The transition time from the frequency f2 to the frequency f4 is, for example, within about 0.2 seconds, and is performed within the starting period t2 of 0.5 seconds. The transition to the dimming mode in the start mode is preset.

  Next, the operation of the discharge lamp lighting device of the present embodiment will be described with reference to FIGS. FIG. 2 is a diagram showing a resonance curve at the time of preheating / starting and lighting in the correlation between the frequency and the lamp voltage, and FIG. 3 is a waveform diagram showing frequency transition for each mode. 3A shows the frequency transition in the present embodiment, and FIG. 3B shows the frequency transition in the prior art.

  When power is applied to this device, the frequency control circuit 9 enters the preheating mode and controls the drive circuit 21 so that the switching elements 22 and 23 of the inverter device 2 are alternately turned on and off at the frequency f1. Then, the timer circuit 10 is operated to start counting the preheating period t1. At this time, high-frequency current from the inverter device 2 flows to the coupling capacitor 6 via the choke coil 4 → one filament of the lamp 3 → the starting capacitor 5 → the other filament of the lamp 3, and the coupling capacitor 6 is charged. The high-frequency current flows in the opposite direction, and this is repeated based on the on / off of the switching elements 22 and 23 to preheat the pair of filaments of the lamp 3.

  On the other hand, the frequency control circuit 9 determines whether or not the preheating period t1 has passed through the timer circuit 10, and when the elapse of the preheating period t1 is detected, the frequency is shifted from f1 to f2 as shown in FIG. Then, the start mode is entered, and the drive circuit 21 is controlled so that the switching elements 22 and 23 of the inverter device 2 are alternately turned on and off at the frequency f2. By this control, a high frequency high voltage is generated in the starting capacitor 5 due to the series resonance of the choke coil 4 and the starting capacitor 5, and this high frequency lamp voltage is applied to the lamp 3. Further, the frequency control circuit 9 determines whether or not the lamp 3 is turned on through the lighting detection circuit 8, and when the lighting detection signal is input from the lighting detection circuit 8, the illumination sensor 7 detects the lighting of the lamp 3. It is determined that the light control mode has been set, and a preset light control mode is entered. When the lamp 3 is lit, the lamp voltage shifts from the point A of the resonance curve during preheating / starting to the point B of the resonance curve during lighting as shown in FIG.

  When the lamp 3 does not light up within the start period t2 counted by the timer circuit 10, the frequency control circuit 9 regards the lamp as abnormal and issues a stop command to the drive circuit 21 of the inverter device 2 to perform switching. The on / off of the elements 22 and 23 is stopped.

  As described above, when the dimming mode is entered by lighting the lamp within the starting period t2, the frequency f2 is immediately shifted (within 0.2 seconds) from the frequency f2 (see FIG. 2), and the inverter device 2 is switched on at this frequency f4. The drive circuit 21 is controlled so that the switching elements 22 and 23 are alternately turned on and off. In this case, since the transition from the frequency f2 in the start mode to the frequency f4 in the dimming mode is performed immediately, the frequency is substantially vertical compared to the conventional case where the frequency transitions stepwise as shown in FIG. Transition (see FIG. 3A).

  As described above, according to Embodiment 1, when lighting of the lamp 3 is detected by the lighting detection circuit 8 in the start mode, the frequency f2 in the start mode is immediately changed to the frequency f4 in the dimming mode set in advance. Since the transition is made, there is no stepwise light change of the lamp that is confirmed when the lamp 3 is dimmed and the discomfort due to the stepwise light change can be eliminated.

Embodiment 2. FIG.
FIG. 4 is a circuit block diagram showing a schematic configuration of a discharge lamp lighting device according to Embodiment 2 of the present invention, and FIG. 5 is a waveform diagram of a lamp voltage that changes for each mode. In addition, the same code | symbol is attached | subjected to the same or equivalent part as Embodiment 1 demonstrated in FIG. 1, and description is abbreviate | omitted.
The discharge lamp lighting device of the present embodiment includes a lighting detection circuit 8a that detects lighting of the lamp 3 from the lamp voltage. The lighting detection circuit 8a has the lamp voltage when the lamp 3 is lit in the start mode as a lighting discrimination value, and lights up when the lamp voltage (high frequency high voltage) applied to the lamp 3 falls to the lighting discrimination value. The detection signal is output to the frequency control circuit 9. The lighting determination value described above is the same voltage value as point B of the resonance curve during lighting shown in FIG.

  In the present embodiment, after the preheating mode, a high frequency high voltage is generated in the starting capacitor 5 by the series resonance of the choke coil 4 and the starting capacitor 5 and applied to the lamp 3 by the frequency f2 in the starting mode. When the lamp 3 is lit at this lamp voltage (high frequency high voltage), as described above, the lamp voltage shifts from the point A of the resonance curve during preheating / starting to the point B of the resonance curve during lighting (see FIG. 2). . That is, as shown in FIG. 5, the lamp voltage decreases from point A to point B. When the lighting detection circuit 8a detects a decrease in the lamp voltage to point B (lighting determination value), it outputs a lighting detection signal to the frequency control circuit 9, and at this time, the frequency control circuit 9 immediately (within 0.2 seconds). The frequency is shifted from f2 to f4, and the drive circuit 21 is controlled so that the switching elements 22 and 23 of the inverter device 2 are alternately turned on and off at this frequency f4.

  As described above, according to the second embodiment, it is determined that the lamp 3 is lit when the lamp voltage is reduced to the lighting determination value set in the lighting detection circuit 8 in the start mode, and the frequency f2 in the start mode is determined. Since the shift to the frequency f4 of the dimming mode set in advance is immediately performed, the stepwise light change of the lamp that is confirmed when the lamp 3 is dimmed is eliminated, and the stepwise light change The discomfort caused by can be eliminated.

Embodiment 3 FIG.
FIG. 6 is a circuit block diagram showing a schematic configuration of a discharge lamp lighting device according to Embodiment 3 of the present invention, and FIG. 7 is a waveform diagram of a lamp voltage that changes for each mode. In addition, the same code | symbol is attached | subjected to the same or equivalent part as Embodiment 1 demonstrated in FIG. 1, and description is abbreviate | omitted.
The discharge lamp lighting device of the present embodiment includes a lighting detection circuit 8b that detects lighting of the lamp 3 from the voltage generated in the coupling capacitor 6. This lighting detection circuit 8b has the voltage of the coupling capacitor 6 when the lamp 3 is lit in the start mode as a lighting discrimination value, and the lighting detection signal when the voltage of the coupling capacitor 6 rises to the lighting discrimination value. Is output to the frequency control circuit 9.

  In the present embodiment, after the preheating mode, a high frequency high voltage is generated in the starting capacitor 5 by the series resonance of the choke coil 4 and the starting capacitor 5 and applied to the lamp 3 by the frequency f2 in the starting mode. When the lamp 3 is lit at this lamp voltage (high frequency high voltage), as described above, the lamp voltage shifts from the point A of the resonance curve during preheating / starting to the point B of the resonance curve during lighting (see FIG. 2). . At this time, as shown in FIG. 7, the voltage of the coupling capacitor 6 is low when the lamp voltage is at the point A, and is high when the lamp voltage is lowered to the point B due to lamp lighting. The frequency control circuit 9 outputs a lighting detection signal to the frequency control circuit 9, and the frequency control circuit 9 immediately shifts the frequency from f2 to f4 (within 0.2 seconds). Then, the drive circuit 21 is controlled so that the switching elements 22 and 23 of the inverter device 2 are alternately turned on and off at the frequency f4.

  As described above, according to the third embodiment, it is determined that the lamp 3 has been lit when the voltage of the coupling capacitor 6 has increased to the lighting determination value set in the lighting detection circuit 8 in the start mode, and the start is started. Since the frequency f2 in the mode is immediately shifted to the frequency f4 in the preset dimming mode, there is no stepwise change in light after starting the lamp, which is confirmed when the lamp 3 is dimmed. , Can eliminate discomfort due to gradual light changes.

  In each of the embodiments described above, when the lamp 3 is lit in the start mode, the mode is changed to the dimming mode. However, in addition to this, the mode may be changed to the all-light mode. When the remote control is equipped with a switch for dimming mode / all light mode, etc., and all light mode is selected with this switch, as described above, immediately after the lamp is turned on (within 0.2 seconds), the frequency f2 is shifted to the frequency f3. However, the drive circuit 21 is controlled so that the switching elements 22 and 23 of the inverter device 2 are alternately turned on and off at this frequency f3. As a result, there is an effect that all the lights are turned on immediately without confirming the light change of the lamp 3 that is turned on in the start mode.

  Moreover, although the frequency of the light control mode after the start mode has been described as being fixed as f4, it is not limited to this. For example, when the dimming level is arbitrarily set with a remote controller or the like, the dimming mode may be entered at a frequency corresponding to the dimming level.

It is a circuit block diagram which shows schematic structure of the discharge lamp lighting device which concerns on Embodiment 1 of this invention. It is a figure which shows the resonance curve at the time of the preheating and start-up, and lighting in the correlation of a frequency and a lamp voltage. It is a wave form diagram which shows the transition of the frequency for each mode. It is a circuit block diagram which shows schematic structure of the discharge lamp lighting device which concerns on Embodiment 2 of this invention. It is a wave form diagram of the lamp voltage which changes for every mode. It is a circuit block diagram which shows schematic structure of the discharge lamp lighting device which concerns on Embodiment 3 of this invention. It is a wave form diagram of the lamp voltage which changes for every mode.

Explanation of symbols

1 DC power supply, 2 inverter device, 21 drive circuit, 22, 23 switching element, 3 lamp, 4 choke coil, 5 starting capacitor, 6 coupling capacitor, 7 illumination sensor, 8, 8a, 8b lighting detection circuit, 9 frequency control Circuit, 10 Timer circuit.

Claims (5)

An inverter device that converts the voltage of the DC power source into high-frequency power by a drive signal of the drive circuit, supplies the discharge lamp connected via a coupling capacitor, and turns it on;
Lighting detection means for detecting lighting of the discharge lamp;
The frequency of the drive signal is controlled according to the preheating mode and the start mode, respectively, and when the lighting of the discharge lamp is detected by the lighting detection means in the start mode, the dimming mode is immediately shifted to the preset dimming mode. A discharge lamp lighting device comprising frequency control means for controlling the frequency of the drive signal.   The frequency control means controls the frequency of the drive signal so as to immediately shift to the all-light mode when lighting of the discharge lamp is detected by the lighting detection means in the start mode. Discharge lamp lighting device.   The discharge lamp lighting device according to claim 1, wherein the lighting detection unit detects lighting of the discharge lamp based on a detected illuminance of an illuminance sensor.   The discharge lamp lighting device according to claim 1, wherein the lighting detection unit detects lighting of the discharge lamp based on a high frequency voltage applied in a start mode. The discharge lamp lighting device according to claim 1, wherein the lighting detection unit detects lighting of the discharge lamp based on a voltage generated in a coupling capacitor in a start mode.

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