JPH06151077A - Microwave discharge light source device - Google Patents

Abstract

PURPOSE:To provide a microwave discharge light source device capable of stabilizing the light emitting output. CONSTITUTION:A microwave discharge light source device is provided with a waveguide 2 for guiding the microwave oscillated by a microwave oscillator 1; a microwave resonant cavity body 3 connected to the waveguide 2 through a feed port 4; and a lamp vessel 6 provided in the microwave resonant cavity body 3 in which a discharge light emitting material excited by the microwave to discharge and emit light is received. Further, the device is provided with a dielectric bar 8 provided on the microwave resonant cavity body 3 in such a manner as to be capable of protruding and recessing to change the resonant wavelength of the microwave resonant cavity body 3 according to the protruding and recessing quantity; an optical sensor 13 for detecting the intensity of the light released from the lamp vessel 6; and a control device 14 for operating a pulse motor 12 on the basis of the detection signal of the optical sensor 13 to control the protruding and recessing quantity of the dielectric bar 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave discharge light source device for exciting a discharge luminescent material in a lamp vessel with microwaves to emit light.

[0002]

2. Description of the Related Art Recently, as a light source device for generating ultraviolet rays, a microwave discharge light source device has been put into practical use in place of a conventional DC discharge excitation mercury lamp. The microwave discharge light source device has a microwave oscillator that oscillates microwaves. The microwave oscillated from this oscillator is guided from the waveguide into the microwave resonant cavity through the feed port.

A lamp container having a discharge light emitting substance sealed therein is disposed in the microwave resonant cavity. When the microwave is introduced into the microwave resonance cavity body from the power supply port, the discharge luminescent material is excited to discharge and emit light.

Although such a microwave discharge light source device may have a faster start-up at the time of start-up than a DC discharge excitation mercury lamp or the like, at present, a start-up time of about 5 seconds is required. Therefore, it is required to further shorten the rise time.

When the resonance wavelength in the microwave resonant cavity is λg, the cutoff wavelength is λc, the permittivity is ε, and the wavelength in free space is λo, the relationship between them can be expressed by the following equation. . ε / λo ² = 1 / λc ² + 1 / λg ² ... (1) formula

The above-mentioned dielectric constant ε greatly changes when the discharge luminescent material in the lamp vessel is excited and turned into plasma. However, the matching of the microwave resonance of the microwave resonant cavity is taken as a parameter when the lamp container is discharged. Therefore, the excitation of the lamp vessel is performed by the microwave leaking from the power supply port until the discharge is started. Therefore, the excitation efficiency of the lamp vessel becomes low, and as described above, it takes about 5 seconds until lighting.

Further, since the dielectric constant of the discharge luminescent material strongly depends on the temperature rise due to discharge, gas pressure, mixing ratio, etc., these dielectric constants are used as parameters to determine the resonance wavelength of the microwave resonant cavity. It was difficult to design.

[0008]

Thus, conventionally, the resonance wavelength of the microwave resonant cavity is set by parameterizing the permittivity of the lamp vessel during discharge. Therefore, matching of the microwave resonant cavities cannot be achieved until the discharge is started, and it may take a long time before lighting.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a microwave discharge capable of matching the resonance wavelength of the microwave resonant cavity not only at the time of discharge but also before the start of discharge. It is to provide a light source device.

[0010]

To solve the above problems, the present invention provides a microwave oscillator for oscillating a microwave, a waveguide for guiding the microwave oscillated by the microwave oscillator, and a waveguide for the same. A microwave resonant cavity body connected to the tube through a power supply port, a lamp vessel provided in the microwave resonant cavity body, and containing therein a discharge luminescent substance that is excited by the microwave and discharges and emits light.
An adjusting body which is provided in the microwave resonance cavity body so as to be able to move back and forth and changes the resonance wavelength of the microwave resonance cavity body according to the amount of advance and retreat, driving means for driving the adjustment body forward and backward, and emission from the lamp vessel. It is characterized by comprising an optical sensor for detecting the intensity of the emitted light, and a drive control means for operating the drive means based on the detection signal of the optical sensor to control the amount of advance / retreat of the adjusting body.

[0011]

According to the above structure, the resonance wavelength of the microwave resonant cavity can be changed by advancing and retracting the adjusting body. Therefore, by adjusting the resonance wavelength before and after the start of discharge, light emission can be achieved. It is possible to speed up the rise of the battery and to stabilize the output during discharge.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG.

In the figure, reference numeral 1 is a microwave oscillator. One end of a waveguide 2 is connected to the microwave oscillator 1. A microwave resonant cavity body 3 is connected to the other end of the waveguide 2. A power feed port 4 is formed at the connecting portion between the waveguide 2 and the microwave resonant cavity 3. Therefore, the microwave oscillated and output from the microwave oscillator 1 is transmitted through the waveguide 2 and fed into the microwave resonant cavity 3 through the feed port 4.

The microwave resonant cavity 3 has a cylindrical shape with one end closed, and a metal mesh 5 as a member for transmitting light and blocking microwaves is provided on the other open end. .

A lamp container 6 is arranged inside the microwave resonant cavity 3. The lamp container 6 is made of a material having excellent heat resistance, for example, quartz glass, and is formed into a hollow spherical shape. The lamp vessel 6 is filled with a discharge luminescent substance. As the discharge luminescent material,
Helium (He), Neon (Ne), Krypton (K
r), fluorine (F ₂ ) mixed gas, He, Ne, argon (Ar), F ₂ mixed gas, He, Ne, F ₂ mixed gas, Ne, F ₂ mixed gas, etc. It is possible to output light of different wavelengths depending on the mixed components of.

A through hole 7 is formed in the side wall of the microwave resonant cavity 3. Assuming that the permittivity is ε, a dielectric rod 8 as an adjuster, which is made of a dielectric material with ε ≧ 1, is inserted into and supported by the microwave resonant cavity 3 so as to move forward and backward. ing. A rack 9 is provided at the base end of the dielectric rod 8, and a pinion 11 is meshed with the rack 9.

The pinion 11 is attached to the rotary shaft 12a of the pulse motor 12. Therefore, when the pulse motor 12 operates and the pinion 11 is rotationally driven, the dielectric rod 8 is driven forward and backward via the rack 9.

The light output from the lamp vessel 6 and transmitted through the metal mesh 5 is detected by the optical sensor 13. The detection signal from the optical sensor 13 is the control device 14
Entered in. The controller 14 operates the pulse motor 12 according to the intensity of the detection signal from the optical sensor 13. Thereby, the microwave resonant cavity 3
The protruding length of the dielectric rod 8 is controlled. Further, the control device 14 controls the start / stop of the microwave resonator 1. Next, the operation of the microwave discharge light source device having the above configuration will be described.

First, before the discharge is started before the microwave oscillator 1 is operated to excite the lamp vessel 6 with microwaves, the dielectric constant in the microwave discharge cavity 3 is resonated by the dielectric rod 8 before the discharge. It is set to take the matching of. That is, based on the relationship between the permittivity ε in the microwave discharge cavity 3 and the resonance wavelength λg shown in the equation (1), the dielectric rod 8 is moved back and forth so that the permittivity ε matches the resonance wavelength λg. Set the amount.

Dielectric constant ε according to the amount of advance / retreat of the dielectric rod 8
Is set to match the resonance wavelength λg, the microwave resonator 1 is activated to generate microwaves. The permittivity ε in the microwave discharge cavity 3 is
Since the resonance is matched by the dielectric rod 8, the lamp vessel 6 is instantly excited and starts discharging. Therefore, it is possible to speed up the rise until light emission. At that time, the intensity of light detected by the optical sensor 13 is stored in the control device 14 as a maximum value.

In this way, when the discharge is started, the permittivity ε of the lamp vessel 6 changes due to factors such as temperature rise, so the resonance wavelength also changes and the Q value decreases, and the lamp vessel 6 is excited. Efficiency is reduced.

When the intensity of light output from the lamp vessel 6 decreases due to the decrease in excitation efficiency, the fact is detected by the optical sensor 13 and input to the control device 14. As a result, a drive signal for driving the pulse motor 12 is output from the control device 14, and the dielectric rod 8 is driven in a direction to compensate for the change in the dielectric constant ε of the lamp vessel 6. That is, the dielectric constant ε in the microwave resonant cavity 3 is corrected so as to match the resonant wavelength.

Specifically, when the discharge luminescent material in the lamp vessel 6 is excited and turned into plasma, its dielectric constant decreases, so that the dielectric rod 8 is a microwave discharge cavity body so as to make up for the decrease. It is made to enter in 3.

The dielectric rod 8 is connected to the microwave discharge cavity 3
When the dielectric constant ε and the resonance wavelength λg in the microwave discharge cavity 3 are matched by entering the inside, the intensity of the light output from the lamp vessel 6 increases.

After that, the driving of the dielectric rod 8 is feedback controlled so that the detection signal detected by the optical sensor 13 becomes maximum. That is, even if the dielectric constant ε in the microwave discharge cavity body 3 changes under various conditions after the start of the discharge, the resonance wavelength matching with the microwave discharge cavity body 3 is automatically performed by the detection signal from the optical sensor 13. Will be taken.

As described above, the matching of the resonance wavelength is adapted to the permittivity of the microwave discharge cavity 3 before the start of the discharge, so that the rise to the light emission at the time of the start can be shortened to about 1 second. I was able to. Moreover, after the start of discharge, even if the dielectric constant in the microwave discharge cavity 3 changes due to various factors, the dielectric rod 8 is driven according to the change, and the intensity of the output light becomes maximum. Since the matching with the resonance wavelength is automatically taken, the light emission is performed in a stable state.

Although the dielectric rod is used as the adjusting body for changing the resonance wavelength of the microwave resonant cavity in the above embodiment, the shape is not limited to the rod shape and may be a plate shape. The material is not limited to the dielectric material, and may be metal or the like.

Further, as the driving means for driving the adjusting body forward and backward, a linear motor or a cylinder may be used instead of the rack and pinion, and the point is not limited at all.

[0029]

As described above, according to the present invention, the permittivity in the microwave resonant cavity can be adjusted by advancing and retracting the adjusting body in and out of the microwave resonant cavity, and the advance / retreat drive is performed in the lamp container. It is controlled by a detection signal from an optical sensor that detects the intensity of light emitted from the device.

Therefore, by matching the resonance wavelength matching by the dielectric constant of the microwave resonant cavity with the parameters before the start of discharge, the rise time until light emission at the start can be shortened, and after the rise. Since the change in the dielectric constant of the microwave resonant cavity is compensated by the adjuster driven forward and backward and is always matched with the resonant wavelength, the output can be stabilized.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an embodiment of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Microwave oscillator, 2 ... Waveguide, 3 ... Microwave resonance cavity body, 4 ... Feed port, 6 ... Lamp container, 8 ... Dielectric rod (adjusting body), 12 ... Pulse motor (driving means), 13 ...
Optical sensor, 14 ... Control device (drive control means).

Claims (1)

[Claims] 1. A microwave oscillator for oscillating a microwave, a waveguide for guiding the microwave oscillated by the microwave oscillator, and a microwave resonant cavity body connected to the waveguide through a feed port. A lamp container provided in the microwave resonant cavity, in which a discharge luminescent substance that is excited by the microwave and discharges and emits light is contained;
An adjusting body which is provided in the microwave resonance cavity body so as to be able to move back and forth and changes the resonance wavelength of the microwave resonance cavity body according to the amount of advance and retreat, driving means for driving the adjustment body forward and backward, and emission from the lamp vessel. And a drive control means for operating the drive means on the basis of a detection signal of the light sensor to control the amount of advance / retreat of the adjusting body. Wave discharge light source device.