JP2008053131A - Discharge lamp lighting apparatus and luminaire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a discharge lamp lighting apparatus which has a comparatively simple structure and can easily detect a life terminal status of each of discharge lamps in an actual use and can conduct a suitable operation. <P>SOLUTION: The discharge lamp lighting apparatus includes a circuit 1 to rectify and smooth an alternate power source Vs, an inverter circuit 2 to convert the output into a high frequency wave and a controlling circuit 4 to control an operation of the inverter circuit 2, and also provided with a sweep status detecting circuit 5 to detect a required time from a preheating start-up till lighting of the discharge lamp FL or both end voltages of a discharge lamp FL just before the discharge lamp is lit by a method of sweep preheating/starting-up in which the frequency is reduced continuously and a memory circuit 6 to memorize at least a detected value of the sweep status detecting circuit 5 just after starting a use of the discharge lamp. When the detected value of the sweep status detecting circuit 5 is raised up to a predetermined variation ratio against the memorized detected value, the controlling circuit 4 judges that the discharge lamp FL completes its life and conducts a protection operation by controlling an output of or a stoppage of the inverter circuit 2. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a discharge lamp lighting device for lighting a discharge lamp at a high frequency and a lighting fixture using the same.

  In a discharge lamp lighting device, there is a conventional life detection technology for detecting the end-of-life state of a discharge lamp and performing a protection operation or a life notification, for example, as shown in FIG. 1 of JP-A-2001-185374. (Conventional example 1). In this example, a cumulative counter that integrates the discharge lamp lighting time is mounted on the discharge lamp lighting device, and when a predetermined cumulative lighting time is reached, a protection operation or a notification operation is performed.

Japanese Patent Application Laid-Open No. 2002-83697 provides means for detecting the filament voltage of a discharge lamp, and determines whether the emitter (electron emitting material) of the filament is exhausted, thereby determining the end of life of the discharge lamp. A technique for detecting a state is disclosed (conventional example 2).
JP 2001-185374 A Japanese Patent Laid-Open No. 2002-83697

  However, in the above-described conventional example 1, since it is necessary to determine the cumulative lighting time for determining that it is the life in advance, it is not possible to make a determination according to the life variation of each discharge lamp. In other words, since the cumulative lighting time is set according to the shortest life time including individual variations in the target discharge lamp, the end of life is actually reached even though a considerable life remains. There is a risk that it will be judged.

  On the other hand, in the above-described conventional example 2, since the exhaustion state of the emitter is detected for each lamp, it is possible to determine the life according to the state of the lamp actually used. However, it is inefficient because it is necessary to provide a means for detecting the filament voltage of the discharge lamp in both of the two filaments, and the filament voltage is usually about several volts, so the accuracy of the detection circuit is also low. High precision is required.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to easily determine the end-of-life state of each discharge lamp actually used while having a relatively simple configuration. It is an object of the present invention to provide a discharge lamp lighting device capable of detecting and suitable operation and a lighting fixture using the same.

  In order to solve the above problems, the invention of claim 1 includes a rectifier circuit (D1, D2) for rectifying the AC power supply Vs and a smoothing for smoothing the rectified DC voltage as shown in FIG. A circuit (C1, C2), an inverter circuit 2 that converts the output of the smoothing circuit into a high-frequency output, and a control circuit 4 that controls the operation of the inverter circuit 2, the control circuit 4 preceding the discharge lamp FL. During preheating and starting, the inverter circuit 2 has a sweep preheating / starting system that gradually increases the preheating current and the starting voltage by continuously changing the operating frequency of the inverter circuit 2 from a high frequency to a low frequency. In the discharge lamp lighting device for lighting the discharge lamp FL by the above, the required time from the start of preheating until the discharge lamp FL is lit or both ends of the discharge lamp FL immediately before the discharge lamp FL is lit A sweep state detection circuit 5 that detects pressure, and a storage circuit 6 that stores at least a detection value of the sweep state detection circuit 5 immediately after the start of use of the discharge lamp FL, and for the stored detection value, When the detection value of the sweep state detection circuit 5 rises to a predetermined fluctuation rate, the control circuit 4 determines that the discharge lamp FL is at the end of its life and performs a protective operation by suppressing or stopping the output of the inverter circuit 2 It is what.

  The invention of claim 2 is the life of the apparatus according to claim 1, wherein the time required from the start of preheating until the discharge lamp is turned on is increased by 10% or more relative to the initial value when the discharge lamp is turned on for the first time. It is characterized by doing.

  According to a third aspect of the present invention, in the first aspect, when the voltage across the discharge lamp immediately before the discharge lamp is turned on is increased by 10% or more with respect to the initial value when the discharge lamp is turned on for the first time, the life is determined. It is characterized by that.

  According to a fourth aspect of the present invention, the control circuit 4 according to the first aspect of the present invention is configured so that the control circuit 4 determines the time required from the start of preheating until the discharge lamp is turned on or the rate of change of the voltage across the discharge lamp immediately before the discharge lamp is turned on. By changing the output of the inverter circuit 2, the light output of the discharge lamp is kept substantially constant.

  The invention of claim 5 is a lighting fixture configured using the discharge lamp lighting device and the discharge lamp according to any one of claims 1 to 4.

  According to the first to third and fifth aspects of the present invention, it is possible to detect in advance that the discharge lamp has reached the end of its life by a relatively inexpensive means, and thus it is possible to ensure the safety at the end of the life of the discharge lamp. it can.

  According to the inventions of claims 4 and 5, since the light output can be maintained substantially constant even if the discharge lamp is continuously used for a long period of time, the discharge lamp lighting device having a substantially constant brightness regardless of the use time of the discharge lamp. And a luminaire can be provided.

(Embodiment 1)
FIG. 1 shows a circuit diagram of a discharge lamp lighting device according to Embodiment 1 of the present invention. The discharge lamp lighting device of FIG. 1 rectifies and smoothes the AC power source Vs by a so-called voltage doubler rectifier circuit composed of rectifier diodes D1 and D2 and smoothing capacitors C1 and C2, and the control circuit 4 switches the switching elements Q1 and Q1 of the inverter circuit 2. A high frequency output is obtained by alternately turning on Q2. The load circuit includes a resonance capacitor C4 connected in parallel to the discharge lamp FL, and an LC resonance circuit 3 including a resonance choke coil L1 connected in series to the discharge lamp FL, and the switching circuit Q2 is connected to the switching element Q2 via the DC cut capacitor C3. Connected to both ends. The magnitude of the high-frequency output for the discharge lamp FL is determined by the output voltage of the rectifying / smoothing circuit 1 and the operating frequency of the switching elements Q1, Q2, and the LCR resonance curve configured by the resonant choke coil L1, the resonant capacitor C4, and the discharge lamp FL. Changes according to The operating frequency of the switching elements Q1 and Q2 is set to a slow phase mode higher than the resonance point of the LCR resonance curve, and the output decreases as the operating frequency increases.

  The operation of the discharge lamp lighting device from when the power is turned on until the discharge lamp is lit is as follows. The relationship between the operating frequency of the switching elements Q1 and Q2 controlled by the control circuit 4 and the elapsed time after power-on is as shown in FIG. Switching elements Q1 and Q2 start operating from elapsed time T1. The operating frequency at this time is fMAX, the inverter circuit 2 starts output, and a preheating current starts to flow through the resonance capacitor C4 to the filament of the discharge lamp in accordance with the voltage across the discharge lamp. The operating frequency decreases with the elapsed time T, and the voltage V across the discharge lamp rises accordingly.

  At the elapsed time T4, the voltage V across the discharge lamp reaches a voltage sufficient to start the discharge lamp. When the voltage V across the discharge lamp exceeds the starting voltage of the discharge lamp (voltage at which discharge starts), the discharge lamp is lit and light output can be obtained. The starting voltage of the discharge lamp is relatively low when the discharge lamp is new, and increases as the remaining life decreases, so the time required until the discharge lamp is lit also varies between T2 and T4 depending on the state of the discharge lamp. fluctuate.

  FIG. 3 is a graph showing changes in the voltage V across the discharge lamp at the start when the discharge lamp is new. The time T required until the discharge lamp is lit is T2 in FIG. 2, and the voltage across the discharge lamp immediately before lighting is V2.

  FIG. 4 is a graph showing a change in the voltage V across the discharge lamp at the start when the remaining life of the discharge lamp is short. The time T required until the discharge lamp is lit is T3 in FIG. 2, and the voltage across the discharge lamp immediately before lighting is V3. Thus, in the state where the remaining life of the discharge lamp is reduced, the time T required until the discharge lamp is turned on and the voltage V across the discharge lamp immediately before the turn-on are increased as compared with the case where the discharge lamp is new. .

  In the present embodiment, the sweep state detection circuit 5 that detects the required time T from the start of preheating until the discharge lamp is turned on, and the voltage V across the discharge lamp immediately before the discharge lamp is turned on, and the values of these T and V Is provided. In addition, when the discharge lamp FL is replaced, the stored contents of the storage circuit 6 can be erased by the automatic or manual resetting means 7.

  When a new discharge lamp is lit for the first time, a required time T until the discharge lamp is lit and a voltage V across the discharge lamp immediately before the discharge lamp is lit are detected and stored in the storage circuit 6. This is called the initial value. Thereafter, each time the discharge lamp is turned on, the required time T until the discharge lamp is turned on and the voltage V across the discharge lamp immediately before the discharge lamp is turned on are detected, and the initial values stored in the storage circuit 6 are detected. Compare with

  When the required time T until the discharge lamp is turned on reaches a predetermined fluctuation rate, it is determined that the discharge lamp is at the end of its life, and the control circuit 4 stops driving the switching elements Q1 and Q2. Thereby, the end-of-life state of the discharge lamp can be accurately detected, and abnormal operation such as overheating at the end of the life can be prevented.

  The present embodiment is an example in which a discharge lamp of the FPL27 type mainly used for a desk stand is used. In the FPL 27, since the predetermined fluctuation rate is approximately 10%, the end-of-life state can be accurately detected by setting the predetermined fluctuation rate to 10%.

  Even if the life time of the discharge lamp is the same type, there are individual variations and it is not constant. Since the protection operation by stopping or suppressing the operation of the lighting device can be performed, the discharge lamp can be used without waste until the end of its life.

  In addition, since the said variation rate changes with kinds of discharge lamp, this embodiment can be applied regardless of the kind of discharge lamp by setting a predetermined variation rate according to a discharge lamp.

(Embodiment 2)
In the present embodiment, in the same circuit configuration as that of the first embodiment, the judging means for judging that the discharge lamp is at the end of its life is different. That is, when the discharge lamp voltage V immediately before the discharge lamp is turned on reaches a predetermined fluctuation rate, it is determined that the discharge lamp is at the end of its life, and the control circuit 4 stops driving the switching elements Q1 and Q2. The effect is the same as that of the first embodiment.

  This embodiment is also an example in which a discharge lamp of the FPL27 type mainly used for a desk stand is used. In the FPL 27, since the predetermined fluctuation rate is approximately 10%, the end-of-life state can be accurately detected by setting the predetermined fluctuation rate to 10%.

  In addition, since the said variation rate changes with kinds of discharge lamp, this embodiment can be applied regardless of the kind of discharge lamp by setting a predetermined variation rate according to a discharge lamp.

(Embodiment 3)
The present embodiment is different from the first and second embodiments in the control method by the control circuit 4 in the same circuit configuration. Generally, the light output tends to decrease as the remaining life of the discharge lamp decreases. As shown in FIG. 5, when the output of the inverter circuit 2 is constant, the light output of the discharge lamp gradually decreases as shown in FIG.

  Here, the control circuit is configured to gradually increase the inverter circuit output as shown in FIG. 7 according to the required time T until the discharge lamp is turned on or the fluctuation rate of the voltage V across the discharge lamp immediately before the discharge lamp is turned on. As a result, the light output of the discharge lamp can be kept substantially constant regardless of the cumulative lighting time, as shown in FIG.

  That is, according to the present embodiment, since the discharge lamp can obtain a substantially constant light output from the new time to the end of the life, it is possible to provide a lighting fixture that always maintains a constant brightness.

It is a circuit diagram which shows the circuit structure of Embodiment 1 of this invention. It is explanatory drawing which shows the change of the oscillation frequency at the time of the start of Embodiment 1 of this invention. It is a wave form diagram which shows the output voltage at the time of the start of the life initial stage of Embodiment 1 of this invention. It is a wave form diagram which shows the output voltage at the time of the start of the end of life of Embodiment 1 of this invention. It is 1st operation | movement explanatory drawing of Embodiment 3 of this invention. It is 2nd operation | movement explanatory drawing of Embodiment 3 of this invention. It is 3rd operation | movement explanatory drawing of Embodiment 3 of this invention. It is 4th operation | movement explanatory drawing of Embodiment 3 of this invention.

Explanation of symbols

FL discharge lamp 1 rectification / smoothing circuit 2 inverter circuit 4 control circuit 5 sweep state detection circuit 6 memory circuit 7 reset means

Claims (5)

A rectifier circuit that rectifies an AC power supply, a smoothing circuit that smoothes a DC voltage after rectification, an inverter circuit that converts an output of the smoothing circuit into a high-frequency output, and a control circuit that controls the operation of the inverter circuit, The control circuit has a sweep preheating / starting system that gradually increases the preheating current and the starting voltage by continuously changing the operating frequency of the inverter circuit from a high frequency to a low frequency at the time of preceding preheating and starting of the discharge lamp, In the discharge lamp lighting device for lighting the discharge lamp by the high frequency output of the inverter circuit,
Detection of the sweep state detection circuit that detects the required time from the start of preheating until the discharge lamp lights or the voltage across the discharge lamp immediately before the discharge lamp lights, and at least the sweep state detection circuit immediately after the start of the use of the discharge lamp The control circuit determines that the discharge lamp is at the end of its life when the detection value of the sweep state detection circuit rises to a predetermined fluctuation rate with respect to the stored detection value. A discharge lamp lighting device that performs a protective operation by suppressing or stopping output of the inverter circuit. The release time according to claim 1, wherein the life is determined when the time required from the start of preheating until the discharge lamp is lit increases by 10% or more with respect to the initial value when the discharge lamp is lit for the first time. Electric light lighting device. 2. The discharge lamp according to claim 1, wherein when the voltage at both ends of the discharge lamp immediately before the discharge lamp is turned on is increased by 10% or more with respect to the initial value when the discharge lamp is turned on for the first time, the discharge lamp is determined to be a lifetime. Lighting device. 2. The control circuit according to claim 1, wherein the control circuit changes the output of the inverter circuit in accordance with a required time from the start of preheating until the discharge lamp is turned on or a variation rate of the voltage across the discharge lamp immediately before the discharge lamp is turned on. Thus, the discharge lamp lighting device is characterized in that the light output of the discharge lamp is kept substantially constant. The lighting fixture comprised using the discharge lamp lighting device and discharge lamp as described in any one of Claims 1-4.

Images