JPS63150890A - Discharge lamp starter - 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 [Technical Field 1] The present invention relates to a discharge lamp starting device that includes a bimetal switch and a heater that opens and closes the bimetal switch.

[Background Art 1] A conventional discharge lamp starting device is shown in FIG. 2. This discharge lamp starting device is a discharge lamp La with a filament.
It is connected between non-power terminals t and b of a discharge lamp La, which is connected to an alternating current power supply AC via a ballast as an inductance element. This discharge lamp starting device has two bimetals B, and B2 facing each other, and a contact that is normally closed is formed on the opposing surface of each of the bimetals B+*Bz in the above image. SW, and heaters H+-82 which are thermally coupled to the bimetals B, B, and heat the bimetals B, B2, respectively, and one heater H3.
is used as a bimetal switch to open the bimetal switch SWl when the filament Fl-F2 is sufficiently preheated, and the other heater H2 is used to open the bimetal switch when the discharge lamp La does not light up when the bimetal switch SWl is opened. This is used to close a bimetal switch that closes SW1 and restarts.

To further explain the circuit configuration in detail, a series circuit of a diode D and a bimetal switch SW is connected between non-power terminals a and b of the discharge lamp La via a positive characteristic thermistor R0, and both ends of the diode D A series circuit of a Zener diode ZD as a constant voltage element and a heater H5 for opening the bimetal switch is connected to the heater H1 and the Zener diode ZD for opening the bimetal switch.

A diode D2 and a resistor RI are connected between the connection point of the positive temperature coefficient thermistor R0 and the bimetal switch SW.
, and a series circuit of heater H2 for closing the bimetal switch.

The following is an explanation of the operation of this precedent! do. Now, if the AC power supply AC is turned on, during the positive half cycle of the AC power supply AC, the filament (Fl) and diode D of the discharge lamp La are
4. Bimetal switch SW4, positive characteristic thermistor R0
, filament F2, a preheating current flows through the ballast circuit, and filament F, ,F, is preheated. In addition, during the negative half cycle of the AC power supply, current flows through the circuits of the ballast, filament F2, bimetal switch SW3, bimetal switch opening heater H1, Zener diode ZD, and filament F, and the bimetal switch opens. The heater H3 generates heat. Bimetal B is heated by the heat generated by heater H1, and bimetal B2 is heated.
gradually curves away from the

After the filament films Fl and F2 have been sufficiently preheated, the contacts of the bimetal switch SW1 are opened and the preheating current is interrupted, and at this time, the discharge lamp L is
A kick pulse voltage is applied between both filaments (a) F and -F2, and the discharge lamp La is lit.

When the discharge lamp La is lit in this way, the discharge lamp La
The voltage at the non-power terminals a, b open decreases to the lamp voltage, and in its positive half cycle, the voltage at terminals a1, diode D2, and heater H
3. Current continues to flow through the circuit including the diode D2, the resistor R1, the heater H2 for closing the bimetal switch, and the positive characteristic thermistor Rbs terminal.

Therefore, this current maintains the heat generated by the heater H2 to some extent, keeps the bimetal switch SW1 open, and keeps the discharge lamp La stably lit. Here, when the discharge lamp La is lit, the current that holds the bimetal switch SWI also flows to the heater H2 for closing the bimetal switch, but the lamp voltage of the discharge lamp La is low, and this current also flows to the heater H2 for opening the bimetal switch. Since the current also flows through H5, the bimetal switch SW will not be closed due to the heat generated by the heater H2 for closing the bimetal switch.

The above explanation was about the case where the discharge lamp La was lit normally. Next, the case where the discharge lamp La is not lit even if the bimetal switch SWl is closed will be explained. At this time, the voltage across the discharge lamp La does not decrease to the lamp voltage, and the power supply voltage of the AC power supply AC appears as it is between the non-power supply terminals a and b. In this way, non-power terminals a and b
When the voltage between them reaches the power supply voltage, the voltage between non-power terminals a and b becomes higher than the Zener voltage of the Zener diode ZD, so during the positive half cycle of the AC power supply, the Zener diode ZD becomes conductive. Terminal a1 Zener diode ZD
1. When the diode D2, the resistor R1, the heater H2 for closing the bimetal switch, and the positive temperature coefficient thermistor R8S terminal are connected, a current larger than the above-mentioned holding current flows through the heater H2. Therefore, the heat generated by the heater H2 increases and heats the bimetal B2, causing the bimetal B2 to curve toward the bimetal B side. Therefore, when the discharge lamp La is not lit, the bimetal switch SW is closed again to enter the restart state. In other words, by heating the heater H2, the pimetal l
When the res batch SW + is closed, the heater H
2 becomes smaller, and therefore after a predetermined time, the bimetal switch SW1 is opened again in order for the good metal B2 to return in the direction away from the bimetal B, and the filament switch SW1 is opened again in the same manner as the above starting operation. The capacitive pulse voltage is applied to the open circuit.

The above is an explanation of the operation of the circuit shown in FIG. 2, but such a conventional circuit has the following problems. In other words, the discharge lamp La
If an emissionless state occurs at the end of the life of the discharge lamp La, the discharge lamp La will not light up even if the filaments F1-F2 are sufficiently preheated after the alternating current power supply AC is turned on and the bimetal switch SW1 is opened. Therefore, the above-mentioned restart state is entered, the bimetal switch SW1 is closed, and the 1< bimetal switch SW + is opened again, but at this time, the discharge lamp La is still not lit, and the above-mentioned state is further repeated. It is. In this way, when the bimetal switch SW+ is repeatedly turned on and off, arc discharge occurs between the contacts of the bimetal switch SW1, which causes the problem that the contacts do not last, and the electronic components also generate more heat. There was a problem that caused deterioration of electronic components. By the way, in this discharge lamp starting device, a positive characteristic thermistor R0 is inserted directly in series with the diode D and the series circuit of the bimetal switch SW1.
.

is repeatedly turned on and off, the resistance value of the positive temperature coefficient thermistor R8 increases due to self-heating of the positive temperature coefficient thermistor R0 due to the preheating current, and the bimetal switch SW
The current flowing through the contacts can be reduced to some extent. However, at this time as well, the bimetal switch SW1
The positive temperature coefficient thermistor R0 alone was not sufficient to improve the life of each contact, since it was repeatedly turned on and off.

Therefore, in the past, the circuit configuration was as shown in FIG. 3 or 4. That is, in the circuit shown in #IJ3, a second bimetal switch SW2 is inserted in series with the heater H2 for closing the bimetal switch, and the series circuit of the heater H5 and resistors R2, R, which closes this bimetal switch SW2 is constructed as described above. It is connected to both ends of a series circuit of bimetal switch SW2, resistor R3, and heater H2. Also, vJ
In Figure 4, the series circuit of heater H1, resistor R2, and R is connected to diode D2 and bimetal switch SW2.
Connect between the connection point and the terminal. The series circuit of the heater H1 and one resistor R2, R includes a discharge lamp L.
When the switch a does not light up, a current flows, and when the bimetal switch SW1 is repeatedly turned on and off for a predetermined period of 1 m or more, the bimetal switch SW2 is opened due to the heat generated by the heater H). Therefore, when the bimetal switch SW1 is repeatedly turned on and off for a predetermined period of time, the bimetal B2 of the bimetal switch SW1 becomes bimetal B by cutting off the current flowing to the heater H2.

The bimetal switch SW1 is maintained in an open state so as not to bend to the side, the discharge lamp starting HWI is prevented from shifting to the restart state, and the bimetal switch SW is prevented from being turned on and off. That is, the bimetal switch SW2 or the heater H3 constitutes a so-called timer switch.

However, adding such a bimetal switch SW2 or heater H3 would complicate the circuit configuration and increase the size of the discharge lamp starting device.

[Objective of the Invention J The present invention has been made in view of the above-mentioned points, and its object is to provide a release that can stop the on/off of a bimetal switch during emission control without adding a separate circuit. An object of the present invention is to provide an electric light starting device.

DISCLOSURE OF THE INVENTION 1 (Structure) The present invention provides a bimetal switch in which two bimetals are made to face each other and a contact that is in a normally closed state is formed on each opposing surface of the two bimetals; One heater is used as a bimetal switch opening heater to open the bimetal switch when the filament is sufficiently preheated, and the other heater is used to open the bimetal switch when the bimetal switch is opened. This discharge lamp starting device is used as a heater for closing a bimetal switch to restart the bimetal switch by closing the bimetal switch when the lamp is lit. A series circuit consisting of a diode, a bimetal switch, and a positive temperature coefficient thermistor is connected between the power terminals, and a series circuit consisting of a constant voltage element and a heater for opening the bimetal switch is connected across both ends of the diode so that the diode receives current when the discharge lamp is started. Connect so that current flows in the direction of regulation, and connect the connection point of the heater and constant voltage element for opening the bimetal switch to the non-power terminal of the discharge lamp to which the positive temperature coefficient thermistor is connected. When a heater is connected and the discharge lamp reaches the end of its life and an emission state occurs and the bimetallic switch is turned on and off repeatedly, the increase in resistance due to self-heating of the positive temperature coefficient thermistor causes the heater for closing the bimetallic switch to This prevents the bimetal switch from turning on or off by causing current to continue flowing through the bimetal switch and keeping the bimetal switch closed.

(Example) ! Figure #1 shows a harmful example of the present invention. In this embodiment, the series circuit of the diode D2, the resistor R1, and the heater H2 for closing the bimetal switch in the conventional circuit shown in FIG. It is connected to the opening of the door.

The operation of this embodiment will be explained below. In addition, the operation in which the AC power supply AC is turned on, the bimetal switch SW is opened, and the discharge lamp La is lit, the bimetal switch SW
The operation of maintaining the open state of 1 and keeping the discharge lamp La lit, and the operation of restarting the bimetal switch closing heater H2 when the discharge lamp La is not lit, have positive characteristics. Since the resistance value of the thermistor R0 is several ohms, and the resistance values of the other heaters H, H2, and resistor R4 are several ohms, the circuit operates in the same manner as the circuit shown in FIG.

Now, assuming that the discharge lamp La has reached the end of its life and is in an emissionless state, the ON/OFF state of h<Imetal switch SW1 is repeated as explained in the circuit of FIG. For this reason, the positive characteristic thermistor R due to the repeatedly flowing preheating current
6, the resistance value of the positive temperature coefficient thermistor R0 increases from several Ω to several tens of Ω. When the resistance value of the positive characteristic thermistor R0 becomes large in this way, even when the bimetal switch SW is closed, the voltage at the open non-power terminal a,) becomes almost the power supply voltage, and the Zener diode ZD.

becomes conductive. Therefore, a large current flows through the heater H2 when the bimetal switch SW1 is closed as well as when the bimetal switch SW1 is open, causing the bimetal B2 of the bimetal switch SW1 to curve toward the bimetal B side. At this time, the current flowing through the heater []1 is suppressed because the resistance value of the positive temperature coefficient thermistor Ro is increased, and the heat generation of the heater [I] is suppressed to be smaller than the current when the bimetal switch SW1 is open. It will be done. As a result, the heat generated by the heater H2 becomes greater than the heat generated by the heater H0, and the bimetal switch SW maintains the closed state, and the bimetal switch SW is no longer turned on or off. Note that by maintaining the closed state of the bimetal switch SWI, current continues to flow through the positive temperature coefficient thermistor R8, so it goes without saying that the closed state of the bimetal switch SWI is maintained. As described above, according to the present embodiment, it is possible to prevent the bimetal switch SW1 from repeatedly turning on and off during emission control without adding another circuit such as a timer switch unlike the conventional circuit.

[Effects of the Invention 1] As described above, the present invention provides a bimetal switch in which two bimetals are made to face each other, and a contact that is normally closed is formed on each opposing surface of the two bimetals; One heater is used as a bimetal switch opening heater to open the bimetal switch when the filament is sufficiently preheated, and the other heater is used to open the bimetal switch when the bimetal switch is opened. A discharge lamp starting device used as a heater for closing a bimetal switch to restart the bimetal switch by closing the bimetal switch when the lamp is lit, and for a discharge lamp with a filament connected to an alternating current power source via an inctance element. Diode between non-power terminals,
A series circuit of a bimetal switch and a positive temperature coefficient thermistor is connected, and a series circuit of a constant voltage element and a heater for opening the bimetal switch is connected to both ends of the diode. When the discharge lamp is started, the diode controls the current. The heater for closing the bimetal switch is connected between the connection point of the heater for opening the bimetal switch and the constant voltage element and the non-power terminal of the discharge lamp to which the positive temperature coefficient thermistor is connected. Therefore, when the discharge lamp reaches its final stage and an emis-less state occurs, and the above bimetal switch is repeatedly turned on and off, the voltage across the non-power terminals of the discharge lamp increases due to the increase in resistance value due to self-heating of the positive temperature coefficient thermistor. The current increases regardless of whether the bimetal switch is open or closed, and current can continue to flow through the heater for closing the bimetal switch, thus maintaining the bimetal switch's closed status and preventing the bimetal switch from turning on or off. This has the effect that the life of the contacts will not be shortened by turning them on and off.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of an embodiment of the present invention, FIG. 2 is a circuit diagram of a conventional example, FIG. 3 is a circuit diagram of another conventional example, and FIG. 4 is a circuit diagram of yet another conventional example. It is a diagram. A C is an AC power supply, La is a discharge lamp, F, F2 is a filament, sw, sw2 is a bimetal switch, B...
B2 is a bimetal, ■41 is a heater for opening the bimetal switch, F2 is a heater for closing the bimetal switch,
ZD is a zener diode, D, D2 is a diode,
Ro is a positive characteristic thermistor, R1 is a resistor, a and b are non-power terminals, and L is a ballast. Agent Patent Attorney Ishi 1) Chief Shichio Figure 2 Figure 3 Figure 4 R.

Claims (1)

[Claims] (1) While making two bimetals face each other,
A bimetal switch in which contacts that are normally closed are formed on the opposing surfaces of each of the two bimetals, and a heater that heats each of the bimetals, respectively, are provided, and one heater is activated when the filament is sufficiently preheated. Used as a bimetal switch opening heater to open the bimetal switch, and using the other heater as a bimetal switch closing heater to close the bimetal switch and restart the bimetal switch when the discharge lamp is not lit when the bimetal switch is opened. In the discharge lamp starting device used, a series circuit of a diode, a bimetal switch, and a positive temperature coefficient thermistor is connected between the non-power terminals of a discharge lamp with a filament connected to an AC power source via an inductance element, and a series circuit of a diode, a bimetallic switch, and a positive temperature coefficient thermistor is connected between A series circuit consisting of a constant voltage element and a heater for opening a bimetal switch is connected to both ends so that current flows in the direction in which the diode regulates the current when the discharge lamp is started.
A discharge lamp characterized in that a heater for opening a bimetal switch is connected between a subsequent point of the constant voltage element and a non-power terminal of a discharge lamp to which the positive temperature coefficient thermistor is connected. Electric light starter.