JPS593896A - Device for starting discharge lamp - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] The present invention relates to a discharge lamp starting device.

FIG. 1 shows a conventional discharge lamp starting device.

In the figure, 1 is AC power supply, 2 is stable &, 3 is discharge XJ,
4 is a thermal switch, 4a is a main (Imetal), 4b is an auxiliary (Imetal). When voltage is applied to the ignition lower circuit, a preheating current force; The filament of the electric discharge fire 3 is heated. At the same time, the circuit-opening heater H1 generates heat at a voltage of 150 lb in the opposite direction, and the main metal 4a is heated by force, bends in the opening direction, and after a certain time IWj, it -1 is omitted.At that time, a sudden change in the current occurs. As a result of the stabilization, a high voltage pulse is generated and a light appears.After heating, the current flowing through the resistor R opens the heater H1, and the thermal switch 4 remains open.

The first start failed, and when restarting, the Zener voltage of Zener diode D2 was set to above the lamp voltage and below the power supply voltage (30W class fluorescent light), then 80V.
Current flows through the circuit-closing heater H8 through the constant voltage diode (before and after)'D, and the heater H' generates heat. +li public bimetal 4b is curved, and both sides (imetal 4a).

4b closes and reheats, and H1 generates heat and performs an opening operation. FIG. 2 shows the bimetals 4a and 4b of the thermal switch, and 1.5.5' is the contact point.

In such a starting device, the distance between the contacts during lighting is largely influenced by the lamp voltage. When the lamp voltage fluctuates, the amount of heat generated by the opening heater H1 fluctuates, the temperature of the bimetal changes, the temperature changes, and eventually the interval between the openings of the contacts 5 and 5' changes. Under normal conditions, if proper contact spacing is maintained, when the lamp voltage decreases due to changes in ambient temperature, power supply voltage, etc., the amount of heat generated by the heater decreases, and the open circuit state of multiple contacts with weak bimetal curvature is maintained. become unable. Furthermore, if the lamp voltage is set to remain open even when the lamp voltage is at its lowest level, the gap between the contacts would be too large under normal conditions, and it would take time to close the circuit upon restart, making it impractical. Ta. It is an object of the present invention to improve the above-mentioned drawbacks, and to always maintain a constant interval between contacts during open circuiting, despite changes in lamp voltage caused by fluctuations in ambient temperature, source voltage, etc.

In the present invention, by setting the Zener voltage of the constant voltage diode that performs switching of the circuit-closing heater to around the effective value of the lamp voltage, a current flows to the circuit-circuit heater by a component exceeding the Zener voltage of the lamp voltage. It is characterized by flowing.

In other words, as the lamp voltage increases, the voltage that exceeds the Zener voltage increases, and current flows through the circuit-closing heater H.
The compensating bimetal 4b is bent so that the distance between the contacts becomes smaller. This is proportional to the effective value of the part where the lamp voltage exceeds the Zener voltage. Therefore, when the lamp voltage is high and the curvature of the main bimetal 4a is large, the compensating bimetal 4b is also made large so that the contact spacing is constant. When the lamp voltage is low and the main bimetal 4a has a moderate degree of curvature, the compensating bimetal 4b hardly bends and the contact spacing can always be kept constant even if the lamp voltage fluctuates.

Figure 3 (a), (Ron indicates the operation, vl is the lamp voltage, V is the zener voltage, (a) shows the lamp voltage when the rung voltage is not too high, and (b) shows the lamp voltage. Indicates the case where is high.

FIG. 4 shows another embodiment of the present invention, in which heater H9
A diode D is inserted into a series circuit of a resistor R.

In the configuration of FIG. 4, the diode D is connected in series with the resistor R, so that the current is 1. Since no current flows in this direction, power consumption during lighting can be reduced.

In the configuration shown in Fig. 5, during normal lighting, the Zener voltage of the constant voltage diode D is higher than the lamp voltage, so no current flows in the direction 11, and power consumption is small. When applied between a and b, it is higher than the Zener voltage, so 1. Current flows in this direction, causing the heater to generate heat and closing the bimetallic circuit of the thermal switch. 1. Also for heater salt for closing circuit during lighting. A current flows in the direction, but it is small compared to the current when the power supply voltage is applied, so it can be almost ignored. Note that the diode D8 in the circuit in Figure 5
If a constant voltage diode D,' is used as shown in Fig. 6,
The amount of heat generated by the heater (2) during lighting can be kept constant against fluctuations in lamp voltage, and the spacing between the contacts can be kept constant.

As mentioned above, even when the lamp voltage fluctuates, the contacts of the thermal switch do not close even when the lamp voltage is low, and the spacing between the contacts of the thermal switch remains constant even when the lamp voltage is high. Since it is located at an appropriate distance, the time to reclose the circuit will be shortened.

It also has the effect of reducing power consumption during lighting.

[Brief explanation of the drawing]

FIG. 1 shows a conventional circuit, FIG. 2 shows a thermal switch, FIGS. 3(a) and 3(b) show operation explanations, and FIGS. 4 to 6 show an embodiment of the present invention. l...AC power supply, 2...ballast, 3...discharge lamp,
4... Thermal switch, 4a... Main bimetal,
41)...Bimetal for compensation, 5,5'...contact,
Hl...Main heater, H3...Compensation heater, D,
, D; ... Zener diode patent applicant

Claims (2)

[Claims] (1) A device in which a commercial power supply is connected to the power supply side filament terminal of a discharge lamp via a ballast, and a thermal switch comprising a main bimetal and a compensation bimetal is connected between the non-power supply side terminals of the discharge lamp via a diode. A discharge lamp starting device characterized in that a diode and a Zener diode whose Zener voltage is set to be higher than the lamp voltage and lower than the power supply voltage are inserted in series with a heater circuit for heating the compensation bimetal. (2) The discharge lamp starting device according to claim 1, wherein means for reducing power consumption is added to the heater circuit for heating the main bimetal.