JPH02260585A - Ion laser apparatus - Google Patents

Abstract

PURPOSE:To prolong the life of an ion laser tube by a method wherein a filament current corresponding to a discharge current is supplied to control a filament temperature at an optimum value. CONSTITUTION:A discharge current signal amplified by a differential amplifier 9 is inputted to a comparison amplifier 14 through a buffer amplifier 13 and a resistor 25 as a non-inverting input. The non-inverting input is a summation signal which is generated by adding a signal transmitted through a resistor 24 to a signal transmitted through the resistor 25. Then the summation signal is compared with a reference voltage generated by a reference voltage source and a variable resistor 26 by the comparison amplifier 14. A transistor 16 is driven by the output signal of the comparison amplifier 14. Then a current is applied to the primary winding of a pulse transformer 17 and a voltage is induced in the secondary winding of the pulse transformer 17 and a DIAC 18 and a TRIAC 19 are turned ON and a current is applied to the primary winding of a filament transformer. Therefore, a filament current is supplied. With this constitution, an optimum filament temperature corresponding tn the discharge current of an ion laser tube can be obtained, so that the life of the filament can be prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an ion laser device. More specifically, the present invention relates to the configuration of a novel ion laser device having a function of controlling the filament current supplied to the filament serving as the cathode so as to obtain an optimum filament temperature corresponding to the discharge current of the ion laser tube.

BACKGROUND OF THE INVENTION FIG. 3 is a circuit diagram schematically showing the configuration of a general ion laser device.

As shown in FIG. 3, in this ion laser device, an AC power source 1 is powered manually, and a rectifier circuit 2 is used to control the ion laser tube 3.
Obtain DC power to be supplied as a discharge current to the Due to this discharge current, in the ion laser tube 3, the anode 4 and the cathode 5 are
Arc discharge occurs between the On the other hand, the cathode 5 is a filament, and is supplied with low voltage AC power by a filament transformer 6 to generate heat as described later.

In this ion laser device, the discharge current supplied to the anode 4 flows from the middle point of the secondary winding of the filament transformer 6 to the collector of the power transistor 7, passes through the discharge current detection resistor 8, and is rectified via the ground. Returns to the negative side of circuit 2.

Here, the discharge current signal detected by the discharge current detection resistor 8 is amplified by the differential amplifier 9, and is amplified by the reference voltage source 1.
1 and a reference voltage created by variable resistor 12 by comparator amplifier 10, and drives power transistor 7 to maintain the discharge current constant.

In this type of ion laser device, a red-hot filament is used for the cathode 5 of the ion laser tube 3 in order to cause large current arc discharge. The amount of electrons that this cathode filament can emit is determined by its own temperature, and it is generally known that higher temperatures emit more electrons than others. - Conventional ion laser equipment used on boats is configured so that the discharge current can be varied in order to use varying laser output, but the filament current supplied to the filament is usually is fixed at a specific value to obtain a discharge current of .

Problems to be Solved by the Invention In the above-described ion laser device, the filament is exposed to a low-pressure atmosphere of several torr inside the laser tube, and therefore, as the filament temperature increases, sputtering tends to occur. Therefore, the higher the temperature, the faster the filament deteriorates, and the deteriorated filament causes poor emission and the like, shortening the life of the ion laser tube.

However, in conventional ion laser devices, as mentioned above, the filament temperature is set to a temperature that allows the maximum allowable current to flow, so the filament temperature remains unchanged even when the laser output is lowered. It remained high. Therefore, even when the ion laser tube is used at a low power, the life of the filament is the same as when it is used at a high power, which ultimately shortens the actual life of the ion laser tube.

SUMMARY OF THE INVENTION Therefore, the present invention aims to solve the above-mentioned problems of the prior art and provide a new ion laser tube that has a substantially long life, in which deterioration of the filament is reduced in accordance with the output of the laser tube. The purpose is

According to the present invention, an ion laser tube is provided with an anode and a filament-shaped cathode, a rectifier circuit that converts input AC power into DC power, and a rectifier circuit that converts the ions into DC power. In the ion laser device, the ion laser device includes a discharge current control circuit that controls a discharge current supplied to the laser tube, and a filament lance that supplies low-voltage AC power to the cathode filament. An ion laser device is provided, comprising: a phase control element that controls the phase of alternating current power; and a phase control circuit that drives and controls the phase control element in response to a discharge current supplied to the ion laser tube. be done.

Function: The main feature of the ion laser device according to the present invention is that the temperature of the filament is set to a temperature corresponding to the discharge current of the ion laser tube.

According to a preferred embodiment of the invention, control of the filament temperature is achieved by phasing the primary AC input of the filament transformer supplying the filament current.

That is, the ion laser device according to the present invention includes, for example, a rectifier circuit that converts AC input into DC, an ion laser tube that has an anode and a cathode and causes an arc discharge between the two electrodes, and supplies power to a filament that is the cathode. a power transistor that controls the discharge current flowing through the ion laser tube, a discharge current control circuit that detects the discharge current, drives the power transistor, and controls the discharge current to a constant value, and the primary AC input of the filament transformer. A triac (bidirectional thyristor) that controls the phase of the triac, and a phase control circuit that receives a discharge current detection signal in the discharge current control circuit and drives the triac under phase control.

As will be specifically described later, with the above configuration,
In the ion laser tube according to the present invention, the filament temperature is determined by an appropriate filament current corresponding to the discharge current, so the filament temperature does not rise excessively and the life of the filament can be used effectively.

The ion laser device according to the present invention will be described in more detail below with reference to the drawings, but the following disclosure is only one embodiment of the present invention and is not intended to limit the technical scope of the present invention in any way. do not have.

Embodiment FIG. 1 is a circuit diagram showing an example of the configuration of an ion laser tube according to the present invention.

Also in the ion laser device shown in FIG.
, the basic configuration consisting of a rectifier circuit 2, an ion laser tube 3, and a filament transformer 6 is the same as the conventional ion laser device shown in FIG. is different from conventional ion laser equipment.

That is, AC power supplied from an AC type source 1 is converted into DC power supplied to the ion laser tube 3 by a rectifier circuit 2. The ion laser tube 3 generates arc discharge between the anode 4 and the cathode 5. The cathode 5 is a filament and is supplied with electric power by a filament transformer 6. Also,
The discharge current flows from the middle point of the secondary winding of the filament transformer 6 to the power transistor 7, and the discharge current detection resistor 8
It passes through and returns to the negative side of the rectifier circuit 2. The discharge current signal detected by the discharge current detection resistor 8 is amplified by the differential amplifier 9, and then connected to the reference voltage source 11 and the variable resistor 12.
The comparator amplifier 10 compares the voltage with the reference voltage generated by the comparator 10, and drives the power transistor 7 to keep the discharge current constant.

Furthermore, the circuit shown in FIG. 1 is configured to control the phase of the filament current according to the discharge current supplied as described above. FIG. 2 is a diagram for explaining the filament current control operation, and the operation of this ion laser device will be explained below with reference to the same figure.

The discharge current signal amplified by the differential amplifier 9 as described above becomes a non-inverting input of the comparator amplifier 14 through the buffer amplifier 13 and the resistor 25 as a signal having a waveform as shown in FIG.

Further, the non-inverting input of the comparison amplifier 14 is an addition signal as shown in FIG. 2, which is generated by adding the signal passing through the resistor 24 as shown in FIG. 2 and the signal passing through the above-mentioned resistor 25. It is. Note that the signal passing through the resistor 24 has the same phase as the AC power supply 1 supplied by the transformer 22, and the AC signal that has been AC coupled by the capacitor 23 is passed through the resistor 2.
0 and 21, the signal is biased to a predetermined DC level.

Next, in the comparator amplifier 14, the reference voltage produced by the reference voltage source 27 and the variable resistor 26 is compared with the sum signal of these two signals, and the output signal of the comparator 14 as shown in FIG. Drives transistor 16.

When the transistor 16 is driven, the pulse transformer 17
Current flows through the primary winding and voltage is induced in the secondary winding. Then, first, the diac (bidirectional trigger diode) 18 is turned on, and then the triac 19 is turned on, and current flows through the primary winding of the filament transformer, so that a filament current is supplied.

Note that to control the AC input of opposite phase, the transistor 16 is similarly driven by the signal output from the comparator amplifier 34, and the primary current of the filament transformer 6 is controlled.

In this way, in the ion laser tube arrangement shown in FIG. 1, a filament current corresponding to the discharge current supplied to the ion laser tube 3 is supplied to the filament transformer 6.

As described in detail, the ion laser device according to the present invention includes:
By supplying a filament current that corresponds to the discharge current, the filament temperature is always optimally controlled.

Therefore, deterioration of the filament is minimized in proportion to the output, and the life of the ion laser tube can be substantially extended.

[Brief explanation of drawings]

FIG. 1 shows an embodiment of the ion laser device according to the present invention.
FIG. 2 is a waveform diagram illustrating the operation of the phase control circuit of the circuit shown in FIG. 1, and FIG. 3 is a diagram of a conventional ion laser device. FIG. 2 is a circuit diagram showing the configuration. (Main reference numbers) 1. AC power supply, 2. Rectifying power supply, 3. Ion laser tube, 4. Anode, 5. Cathode (filament), 6. Filament transformer, 7. Power transistor, 8.Discharge current detection resistor, 9.Differential amplifier, 10.Comparison amplifier, 11.
・Reference voltage source, 12.. Variable resistor, 13.. Buffer amplifier, 14.. Comparison amplifier, 15.. Diode, 16.. Transistor, 17. Pulse transformer,

Claims (1)

[Claims] An ion laser tube including an anode and a filament-shaped cathode, a rectifier circuit that converts input AC power into DC power, and a discharge current supplied from the rectifier circuit to the ion laser tube. An ion laser device comprising a discharge current control circuit for controlling a discharge current, and a filament transformer for supplying low-voltage AC power to the cathode filament, further comprising a phase control element for controlling the phase of the AC power supplied to the primary side of the filament transformer. and a phase control circuit that drives and controls the phase control element in response to the discharge current supplied to the ion laser tube.