JPH01253197A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To restrict a resonance voltage at a no-load time by providing a capacitor between non-power side terminals of a fluorescent lamp, and connecting a pair of resistances with each electrode at the time of preheating and lighting the lamp in parallel. CONSTITUTION:At a no-load time when a discharge lamp 11 is removed, an output circuit of a high frequency wave generator 10 is formed by a serial circuit of an inductor 12, a resistance 14, a capacitor 13, and a resistance 15. By selecting the resistance values of the resistances 14, 15 properly, resonance between the inductor 12 and the capacitor 13 is restricted.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a discharge lamp lighting device for lighting a hot cathode discharge lamp such as a fluorescent lamp at high frequency.

(Prior Art) Conventionally, as this type of device, the one shown in FIG. 3, for example, is known. In the figure, reference numeral 1 denotes a high frequency generator, which is composed of an inverter or the like that outputs a rectangular wave AC voltage of, for example, several tens of H2. 2 is a hot cathode discharge lamp, such as a fluorescent lamp.

3 is a current-limiting inductor of the discharge lamp, and 4 is a capacitor as a starting element, which is connected between the non-power supply side terminals of the discharge lamp.

In the case shown in FIG. 1, when starting the discharge lamp 2,
When the high frequency generator 1 is operated to output a rectangular wave AC voltage, the current limiting inductor 3 and the capacitor 4 as a starting element resonate before starting the discharge lamp 2, and this resonant current causes the discharge lamp 2 to While preheating each electrode, a resonant voltage is applied to both ends of the discharge lamp 2. Therefore, the discharge lamp 2 is started and lit at a certain point by the electrode preheating and the application of the resonant voltage. After the discharge lamp 2 is turned on, the capacitor 4 hardly performs any resonance action, and only performs an action to improve the waveform.

(Problems to be Solved by the Invention) However, as shown in FIG.
As shown in the figure, a high voltage accompanied by strange oscillations appeared. To explain this point further, since the circuit between the terminal a, the inductor 3, the high frequency generator 1, and the terminal is open, it is considered that no paranormal vibration occurs. However, the Electrical Appliance and Material Control Law requires grounding according to the maximum voltage value between output terminals, so between the output terminals, that is, the one in Figure 4 above, open terminals a and b are required.
It is necessary to know the output voltage value between. Therefore, when a voltmeter is attached to open terminals a and b to measure the voltage value between open terminals a and b, a closed circuit is formed through the impedance Z of this voltmeter, and the capacitance of this impedance Z and It is considered that the inductor 3 resonates, causing anomalous imaging.

In an actual example, when the high frequency generator 1 is a so-called half-bridge inverter, and the input voltage of this half-bridge inverter is voltage double rectification of the commercial power supply voltage of 100V, the voltage between the open terminals a and b is the thermoelectric lamp shadow voltage. When measured with a meter, it was 170 to iaov. In principle,
Although the input voltage to the high frequency generator 1 should be 140V, it actually exceeded 140V as described above. Furthermore, when the waveform was observed with a synchroscope, it was as shown in FIG.

In this way, even if the voltage is considered to be generated by wearing a measuring device to measure the output voltage,
What actually generates high voltage as a result of measurement is
The above grounding, etc. is required. Incidentally, damping resistors are usually used to prevent strange vibrations, but when the lights are turned on, etc., high voltage is applied to this resistor, causing power loss and heat generation problems. .

Therefore, an object of the present invention is to provide a discharge lamp lighting device that can prevent the voltage between the no-load output terminals from increasing due to unusual vibrations, etc., and can minimize power loss and heat generation. .

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a capacitor between the non-power supply side terminals of a hot cathode forming electric lamp which is energized via a current limiting inductor in a high frequency generator, and , the structure is characterized in that a pair of resistors are provided to be connected in parallel to each electrode of the discharge lamp during preheating and lighting of the discharge lamp.

(Function) In the present invention, even in a no-load state when the discharge lamp is removed, the output terminals are closed by the pair of resistors and capacitors. In this case, the pair of resistors is selected to have a value that does not cause substantial resonance between the current limiting inductance and the capacitor. Therefore, even if a voltmeter is attached to measure the voltage between the output terminals, and as a result, parasitic vibration occurs due to the capacitance component of the voltmeter's impedance and the current limiting inductor, the pair of resistors suppresses parasitic vibration. be done. Therefore, the voltage between the output terminals is essentially the output of the high frequency generator. Further, since no high voltage is applied to the resistor, and only an electrode heating voltage is applied at most, components with low withstand voltage may be used, and power loss and heat generation are small.

(Example) An embodiment of the present invention will be described below with reference to FIG.

Reference numeral 10 denotes a high frequency generator, which outputs, for example, a high frequency voltage exceeding an audible frequency.

Such a high frequency generator 10 can be constructed using a well-known inverter as appropriate. Reference numeral 11 denotes a hot cathode formed electric lamp, for example, a fluorescent lamp, which is energized by the output of the high frequency generator 10. Reference numeral 12 designates a current-limiting inductor for the discharge lamp 11, which is, for example, a choke coil, but may also utilize a transformer glue cage inductance. Reference numeral 13 denotes a capacitor provided between the non-power supply side electrodes of the discharge lamp 11. In this embodiment, the capacitor 13 and the inductor 12 resonate before starting the discharge lamp 11, as in the case of FIG. It is something that performs an action. 14 and 15 are resistors, respectively, and are provided so as to be connected in parallel with each electrode during electrode preheating and lighting of the discharge lamp 11.

Next, the operation of this embodiment will be explained. Starting the discharge lamp 11,
Since the lighting is almost the same as that shown in FIG. 1, the explanation will be omitted. If the discharge lamp 11 is removed or
When there is no load, such as when the electrode of the inductor 12 is disconnected,
and a series circuit of resistor 14, capacitor 13, and resistor 15 form an output side circuit of high frequency generator 10,
By appropriately selecting the resistance values of the resistors 14 and 15, resonance of the inductor 12 and capacitor 13 can be suppressed. Therefore, the voltage between output terminals a and b at this time has a similar shape to the output waveform of the high frequency generator 10 as shown in FIG.

Furthermore, if a voltmeter is attached between output terminals a and b to measure the voltage between output terminals a and b during no-load conditions, the impedance Z of the voltmeter will be present between terminals a and b. , it is easily understood that the presence of the resistors 14 and 15 suppresses the parasitic vibrations between the inductor 12 and the impedance Z.

[Effects of the Invention] As described above, the present invention provides a capacitor between the non-power supply side electrodes of a hot cathode forming electric lamp that is energized via a current limiting inductor in a high frequency generator, and A pair of resistors is provided to be connected in parallel with each electrode during electrode preheating and lighting, so the voltage between the output terminals does not increase due to resonance etc. when there is no load, and it is also possible to connect a voltmeter between the output terminals. Even when the voltmeter is attached to measure voltage, it is possible to suppress parasitic vibrations caused by the impedance of the voltmeter and the inductor. Therefore, it is possible to eliminate the need for grounding, which is regulated by the Electrical Appliance and Material Control Act, or to use a low-grade ground.

Furthermore, a resistor with low breakdown voltage can be used, and power loss and heat generation due to this resistor are also small.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing an embodiment of the present invention, Fig. 2 is a circuit diagram also showing a no-load state, Fig. 3 is a circuit diagram showing a prior art, and Fig. 4 is a circuit diagram also showing a no-load state. 5 is an output voltage waveform diagram of the configuration shown in FIG. 3, and FIG. 6 is an output voltage waveform diagram of the configuration shown in FIG. 1. 10... High frequency generator, 11... Hot cathode forming electric lamp. 12...inductor, 13... capacitor. 14.15...Resistance. Patent applicant Toshiba Electric Materials Co., Ltd. Agent Patent attorney Ono 1) Engraving of Yoshihiro's drawing (no changes in content) Figure 1 Figure 2 2 3 Figure 4
2 Minoh 5 Figure No.
6 Drawing procedure amendment (voluntary) 63.5, 26 1. Indication of the case Patent Application No. 80160 of 1988 2. Name of the invention Discharge lamp lighting device 3. Person making the amendment Relationship with the case Patent applicant Tokyo 1-4-28 (375) Mita, Minato-ku Representative Tsutomu Tsuruo 46 Representative Tsutomu Tsuruo 1-201-1 Funakoshi-cho, Yokosuka, Kanagawa Prefecture 237 Toshiba Electric Materials Corporation Comprehensive Technology Development Center 5 Correction Subject specification and drawings 6, contents of amendment (1) The statement of specification is corrected as shown in the attached sheet (engraved, no change in content) 9 (2) Drawings are corrected as shown in the attached sheet (engraved,
(no change in content).

Claims (1)

[Claims] (1) A high-frequency generator; A hot cathode discharge lamp energized by the output of this high-frequency generator; A current-limiting inductor of this discharge lamp; A capacitor provided between the non-power supply side electrodes of the discharge lamp A discharge lamp lighting device comprising: a pair of resistors connected in parallel with each electrode during preheating and lighting of the discharge lamp.