JPS6118639Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a microwave discharge light source device that lights an electrodeless lamp using microwaves generated by a microwave oscillator.

Recently, this type of photoelectric device has attracted attention. The reason is that in conventional photoelectric devices with electrodes, the lamp life depends on the degree of wear of the electrodes and is short, whereas in microwave discharge light source devices, an electrodeless lamp is used, so the lamp life is short. This is because it is long and has various other advantages.

FIG. 1 is a longitudinal cross-sectional view showing the configuration of this type of microwave discharge light source device, in which 1 is a microwave oscillator, here a magnetron, 2 is its antenna,
3 is a waveguide; 4 is a microwave cavity whose circular shape is at least rotationally symmetric; here, it is shaped like a cup; 5 is a microwave power supply provided at the junction between the cavity 4 and the waveguide 3; 6 is a nearly spherical electrodeless lamp fixed in the cavity 4 by a support 7; 8 is a fan for cooling the magnetron 1 and the lamp 6; 9 is provided in a part of the waveguide 3; A ventilation hole, 10, a mesh plate covering the front surface of the cavity 4, 11
is a box that covers the magnetron 1, waveguide 3, cavity 4, etc.

Next, the operation of the above-mentioned device will be explained. first,
Microwaves generated by magnetron 1 are radiated from antenna 2 into waveguide 3 . The radiated microwave propagates within the waveguide 3 and is radiated into the cavity 4 through the feed port 5, forming a microwave electromagnetic field within the cavity 4 and lighting the lamp 6. .

By the way, in such a light source device, if the lamp 6 does not light up even if the magnetron 1 is driven, that is, microwave power supply is started, in other words, if the microwave power supply is continued even though the lamp 6 is not lit, the magnetron 1 There is a problem in that the light source absorbs the generated microwaves and generates heat, which can even lead to damage, but no conventional light source device of this type has effectively addressed the above problem.

This idea was made in view of the above-mentioned circumstances, and if the electrodeless lamp does not light up even after a predetermined period of time has passed after driving the microwave oscillator, the driving of the microwave oscillator is stopped and the electrodeless lamp is turned off. It is an object of the present invention to provide a microwave discharge light source device that prevents heat generation and damage to the lamp.

An embodiment of this invention will be described below with reference to FIG. FIG. 2 is a circuit diagram showing an embodiment of the microwave discharge light source device according to this invention, in which T indicates a primary winding 1P to which an AC voltage is applied from an AC power source E, two secondary windings 1S, This is a high voltage transformer equipped with 2S. A series circuit of a first capacitor C ₁₁ and a first diode D ₁₁ is connected to both ends of the secondary winding 1S of this transformer T, and a second capacitor C ₁₂ and a second diode D whose connection point is grounded are connected to each other. The series circuit with ₁₂ is connected in antiparallel, and these form a full-wave voltage doubler rectifier circuit. Further, the secondary winding 2S of the transformer T is connected to a microwave oscillator, here a cathode (filament) of a magnetron 1 whose anode is grounded. In this case, the secondary winding 2
One end of S is also connected to the connection point between the first capacitor C ₁₁ and the first diode D ₁₁ .

The microwave generator 12 is configured as described above, and thereby the magnetron 1 generates microwaves to light the electrodeless lamp 6 shown in FIG. 1.

13 is a signal line that detects lighting or non-lighting of the lamp 6 and supplies a signal to a control device to be described later; 14 is a switching contact provided on the primary side of the transformer T of the microwave generator 12; and 15 is a power switch 16. When the switch is turned on, the switching contact 14 is closed and power E is supplied to the microwave generator 12, driving the magnetron 1 and lighting the lamp 6. When the lamp 6 does not light up, the control device receives a signal from the signal line 13 that detects this, and opens the opening/closing contact 14 if the lamp continues to be unlit even after a predetermined period of time has elapsed.

Note that this control device 15 can be constructed using a microcomputer, but if it is constructed using a microcomputer, it will not only be possible to perform the above-mentioned control operations easily, but also
When the lamp is not lit, the on/off contact 14 is repeatedly controlled to open/close several times, or if the lamp still does not light up even after a predetermined number of opening/closing controls, the on/off contact 14 is finally opened, and a non-lighting indication or alarm is issued. Various application controls may be possible.

That is, as described above, this invention provides a switching contact 14 on the primary side of the transformer T when a microwave oscillator such as the magnetron 1 is driven, and this switching contact 14 closes to drive the microwave oscillator. Thereafter, a control device 15 is provided which opens the opening/closing contact 14 when the electrodeless lamp 6 (see FIG. 1) is not lit even after a predetermined period of time has elapsed. Note that opening the switching contact 14 when the electrodeless lamp 6 is not lit after a predetermined period of time has elapsed is because the electrodeless lamp 6 closes the switching contact 14 and drives the magnetron 1 to emit microwaves. Even if the lamp oscillates, there is a time in an unstable region where the discharge start time varies or the discharge is intermittent immediately after the discharge starts, and if non-lighting is detected in this unstable region, a malfunction will occur, so this is to avoid this time. .

Therefore, according to this invention, microwave power supply will not continue under any circumstances when the electrodeless lamp is not lit, and it is possible to prevent heat generation and even damage to microwave oscillators such as magnetrons. There is an effect that it can be done. Furthermore, if the electrodeless lamp is not lit even after a predetermined period of time has elapsed since the opening/closing contact was closed, the opening/closing contact is opened, thereby preventing malfunction. Furthermore, switching contacts are provided on the primary side of the high-voltage transformer, and in order to open and close the secondary side of the high-voltage transformer, a special high-voltage switch that can withstand high voltages of 4,000-odd volts is required. Therefore, a commercial power supply voltage of 100V or 200V can be used, and it is inexpensive.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing the structure of a microwave discharge light source device, and FIG. 2 is a circuit diagram showing an embodiment of the microwave discharge light source device according to this invention. 1... Magnetron, 6... Electrodeless lamp, 1
4... Opening/closing contact, 15... Control device, 16... Power switch, E... AC power supply, T... High voltage transformer, 1P... High voltage transformer primary winding. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] In a microwave discharge light source device that lights an electrodeless lamp using microwaves generated by a magnetron, a switching contact is provided on the primary side of a high-voltage transformer that drives the magnetron, and the switching contact is closed to drive the magnetron. 1. A microwave discharge light source device comprising a control device that opens an opening/closing contact when the electrodeless lamp is not lit even after a predetermined period of time has elapsed.