JPH05335089A - Discharge lamp lighting device - Google Patents

Abstract

PURPOSE:To provide a discharge lamp lighting device having the capability of supplying high-voltage pulses to a lamp having a trigger line, without any loss and with safety. CONSTITUTION:A lamp 4 is connected in series to the secondary side of a step-up transformer 1 via a current limiting element 2 and a pulse generator 3. A trigger line 7 externally laid in the vicinity of the lamp 4 is connected to an electrode not connected to the pulse generator 3 of the lamp 4, and a bypass circuit 8 is provided in parallel to the pulse generator 3 and the lamp 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a discharge lamp lighting device.

[0002]

2. Description of the Related Art Some high pressure mercury lamps and metal halide lamps used for UV cure have a shutter below the lamp so that the shutter can be opened only when ultraviolet rays should be irradiated. It has the disadvantages that the structure is complicated, the cost is high, and the device is large.

Therefore, there is a device in which a lighting device that instantly restarts is used to start the lamp each time irradiation is required. As such a lighting device, for example, as shown in FIG. 2, a lamp 14 is connected in series via a choke coil stabilizer 12 and a pulse generating transformer 13 to the secondary side of a step-up transformer 11, and the lamp 14 is connected outside the lamp. Auxiliary starting electrode (trigger wire) 17 arranged in close proximity
Is connected to the high voltage side, that is, the pulse generation transformer 13 side. The primary side of the step-up transformer 11 is connected to the AC power supply 15. Reference numeral 16 is a pulse generation circuit. Reference numeral 18 is a capacitor for protecting the step-up transformer. The lamp fixture 19 such as the main body of the luminaire and the reflector is grounded. At the time of starting, a high voltage pulse is applied to the lamp 14 from the pulse generating transformer 13.

[0004]

Since the vapor pressure in the lamp is high immediately after the lamp is turned off, it is necessary to give a fairly strong high voltage pulse to restart the lamp immediately after the lamp is turned off. However, the lamp fixture 19 for holding the lamp is made of metal, is located close to the lamp, and is grounded. Therefore, the trigger wire 1 is applied when a high voltage pulse is applied.
There is a possibility that a dielectric breakdown will occur between the lamp 7 and the lamp lamp 19, and the pulse will pass through the path passing through the earth and returning to the pulse generating transformer without passing through a proper circuit, which is very dangerous. In order to prevent this, it is conceivable to use a high withstand voltage for the entire lighting device to block the return path of the pulse from the ground, but this is too costly.

It is an object of the present invention to provide a discharge lamp lighting device which can safely supply a high voltage pulse to a lamp having a trigger wire without loss.

[0006]

In the discharge lamp lighting circuit of the present invention, the lamp is connected in series on the secondary side of the step-up transformer via the current limiting element and the pulse generator, and is placed close to the lamp outside the lamp. The arranged trigger wire was connected to the electrode side of the lamp other than the electrode connected to the pulse generator, and a bypass circuit was provided in parallel with the pulse generator and the lamp.

[0007]

The high-voltage pulse returns to the pulse generator through the lamp and the trigger line and the bypass circuit without causing insulation breakdown with the lamp lamp.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a lighting device comprises a lamp 4 connected in series to a secondary side of a single-winding step-up transformer 1 via a choke coil stabilizer 2 as a current limiting element and a pulse generating transformer 3 as a pulse generator. Connected to. Step-up transformer 1
The primary side of is connected to the AC power supply 5. 6 is a pulse generation circuit. The wiring between the pulse generating transformer 3 and the pulse generating transformer and the lamp 4 (high-voltage side) has a high withstand voltage. A trigger wire (auxiliary starting electrode) 7 arranged outside the lamp in the vicinity of the lamp is connected to the low voltage side, that is, the electrode 4a side which is not the electrode connected to the pulse generating transformer 3 of the lamp.

A bypass circuit 8 for easily passing a pulse is connected in parallel with the pulse generating transformer 3 and the lamp 4. The bypass circuit 8 is composed of, for example, a capacitor that allows only a pulse to pass therethrough. The lamp fixture 9 such as the main body of the lighting fixture and the reflector is grounded.

At the time of starting, a high voltage pulse is applied to the lamp 4 from the pulse generating transformer 3 every half cycle of the input voltage to start the lamp. The high-voltage pulse applied to the lamp before the start of the startup returns to the pulse generation transformer 3 via the bypass circuit 8 through the lamp 4 and the trigger line 7 without causing insulation breakdown with the lamp lighting fixture. The step-up transformer 1 is not limited to the single winding type.

[0011]

According to the discharge lamp lighting device of the present invention, the high voltage pulse can be safely supplied to the lamp without loss.

Since only the pulse generator and the wiring between the pulse generator and the lamp need to have a high withstand voltage, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a circuit of a discharge lamp lighting device of the present invention.

FIG. 2 is a diagram showing a conventional discharge lamp lighting circuit.

[Explanation of symbols]

 1 Step-up transformer 2 Current limiting element (choke coil stabilizer) 3 Pulse generator (pulse generation transformer) 4 Lamp 5 AC power supply 6 Pulse generation circuit 7 Trigger line 8 Bypass circuit 9 Lamp lamp

Claims (1)

[Claims] 1. A lamp is connected in series to a secondary side of a step-up transformer via a current limiting element and a pulse generator, and a trigger wire arranged near the lamp outside the lamp is connected to the pulse generator of the lamp. A discharge lamp lighting device, characterized in that a bypass circuit is provided in parallel with the pulse generator and the lamp while being connected to the electrode side other than the connected electrode.