JPS60235351A - Light source device for microwave discharge - Google Patents

Abstract

PURPOSE:To eliminate the need for a starting lamp in the outside and ensure the reliability of starting by outwardly projecting a hollow supporting rod from the lamp wall of an electrodeless discharge lamp, and charging rare gas or starting and mercury into the hollow. CONSTITUTION:A part of microwaves which are irradiated from a magnetron and are propagated in a waveguide 9 leaks into a cavity 4 from a feeding port 3 and thus a weak leakage electromagnetic field of the microwaves is generated in the inside of the cavity 4. Therefore, discharge is generated in the neighbourhood of the feeding port 3 of a hollow supporting rod 11. The discharge instantaneously propagates into the overall inside of the hollow supporting rod 11 and the ultraviolet rays are irradiated from this portion. As a discharge lamp 5 receives the ultraviolet rays, weak ionization is generated in the inside and therefore the state of starting of the discharge can be fully made by means of even the weak leakage electromagnetic field and the discharge is started. Thereafter, the impedance of the cavity 4 approaches to the matching state and the strong electromagnetic field of the microwaves is generated within the cavity and the discharge lamp 5 absorbs the energy from the electromagnetic field of the microwaves to maintain the discharge and the luminescence.

Description

Detailed Description of the Invention [Technical Field of the Invention] The present invention relates to a microwave discharge light source device that causes an electrodeless discharge lamp to discharge and emit light using a microwave electromagnetic field generated within a microwave cavity, and particularly relates to an improvement in a discharge lamp. It is something.

[Prior art]

Figure 1 shows the microwave cavity part of a conventional microwave discharge light source device. In the figure, 1 is a metal mesh that constitutes the wall surface of the microwave cavity, and this mesh 1 reflects microwaves, but Light passes through. 2 is a microwave cavity bottom plate having a microwave power supply port 3; 4 is a microwave cavity constituted by the metal mesh 1 and the bottom plate 2; 5 is a spherical electrodeless discharge disposed within this cavity 4; The lamp 6 is a lamp support rod that protrudes integrally from the wall of the discharge lamp 5, and the support rod 6 is inserted into the recess 7a of a support 7 made of a dielectric member attached to the bottom plate 2 so as to straddle the power supply port 3. and holds the discharge lamp 5. 8 is a flange for attaching the metal mensch 1 to the bottom plate 2; 9 is a waveguide;
Reference numeral 10 indicates a small right-hand polar type ultraviolet lamp.

In the conventional microwave discharge optical device configured as described above, microwaves emitted from a magnetron (not shown) connected to the waveguide 9 propagate within the waveguide 9 and are connected to the feed port 3. from the inside of the microwave cavity 4. At this time, since the impedance of the cavity 4 is not in a matching state, the microwave guided into the cavity 4 is only a leakage microwave leaking from the feed port 3, and most of it is reflected from the feed port 3.

Therefore, the microwave electromagnetic field generated within the cavity 4 becomes very weak, making it difficult to start the discharge rung 5, resulting in the problem that starting is not ensured. For this reason, in the conventional device, an ultraviolet lamp 10 operated by a power source separate from the magnetron is provided outside the cavity 4, and the ultraviolet lamp 10 is turned on simultaneously with or in advance of the operation of the magnetron to irradiate the discharge lamp 5 with ultraviolet rays. This lamp 5
A method is used to induce weak ionization inside the

As a result, the lamp 5 can be sufficiently started even by a weak microwave electromagnetic field, and starting is ensured. Note that when the discharge lamp 5 starts discharging, the impedance of the cavity 4 is in a matching state, so the microwave electromagnetic field generated within the cavity 4 also becomes stronger, and the lamp 5 absorbs energy from the microwave electromagnetic field and discharges. , and continues to emit light. As mentioned above, the light emitted from rung 5 is
and is discharged to the outside of the cavity 4. In this way, in the conventional device, an ultraviolet lamp IO is required in addition to the lamp 5, which makes the device complicated.Also, since the lamp 5 is an electrodeless discharge lamp, its lifespan is relatively long. The rung 10 has a short lifespan and has the disadvantage that it needs to be replaced while the discharge lamp 5 is in use.

[Summary of the invention]

This invention was made with the aim of improving such drawbacks, and by protruding a hollow support rod outward from the lamp wall of the electrodeless discharge rung and filling the hollow with a starting rare gas and mercury, the external The present invention provides a microwave discharge light source device that eliminates the need for a starting lamp and can ensure reliable starting.

[Embodiments of the invention]

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, the same reference numerals as in FIG. 1 indicate the same parts, so the explanation will be omitted. Reference numeral 11 denotes a hollow support rod that protrudes from the lamp wall of the electrodeless discharge rung 5 toward the power supply port and is made of the same material as the lamp 5.
a, and holds the electrodeless discharge lamp 5. In the hollow 12 of the hollow support rod 11, a rare gas for starting and mercury having a saturated vapor pressure or less at room temperature are sealed.

Next, the operation will be explained. A portion of the microwaves radiated from the magnetron and propagated within the waveguide 9 leaks into the cavity 4 through the feed port 3 and generates a weak microwave leakage electromagnetic field inside the cavity 4. However, this leakage electromagnetic field has a property that it is strong near the power supply port 3 and becomes weaker as it moves away from the power supply port 3, so that discharge occurs in a portion of the hollow support rod 11 that is close to the power supply port 3. This discharge instantaneously causes the hollow support rod 11
It spreads throughout the interior of the body, and this area is where ultraviolet rays are emitted.

Therefore, since the discharge lamp 5 receives the ultraviolet rays, weak ionization occurs inside the discharge lamp 5, and therefore, even with a weak leakage electromagnetic field, the discharge lamp 5 becomes in a state where it can sufficiently start the discharge, and starts the discharge. Thereafter, as in the conventional case, the impedance of the cavity 4 approaches a matching state, a strong microwave electromagnetic field is generated within the cavity, and the radiating lamp 5 absorbs energy from the microwave's magnetic field and discharges. , and continues to emit light.

In the embodiment, a case has been described in which mercury vapor at a pressure equal to or lower than the saturated vapor pressure is sealed in the hollow support rod 11, but even if the amount of mercury sealed is increased beyond that, the same effect on starting reliability can be obtained. It will be done. However, the light emission inside the support rod is unnecessary and has no particular meaning after the discharge lamp 5 starts discharging.

〔Effect of the invention〕

As described above, according to the present invention, the hollow support rod protrudes outward from the lamp wall of the electrodeless discharge lamp.

By filling the hollow space with a rare starting gas and mercury, an external ultraviolet lamp is not required and reliable starting performance can be ensured. Further, eliminating the need for an external ultraviolet lamp has the effect of eliminating the need to frequently replace the short-life ultraviolet lamp, and making it possible to manufacture the lamp at low cost.

[Brief explanation of the drawing]

Figure 1 shows a cross section of a conventional microwave number turtle light source device.
FIG. 2 is a sectional view of a microwave discharge light source device according to the present invention. 3.Power supply port, 4..Microwave cavity, 5..Number of electrodes: 1
L lamp, 7...Support body, 11...Hollow support rod, 12
・Hollow part of support rod. In addition, in the figures, the same reference numerals indicate the same or corresponding parts. Agent Masuo Oiwa No. 11 No. 2 Continuation of Figure 1 Page 0 Inventor Hiroshi Ito Within 5, Ofuna, Kamakura City @ Inventor Kenji Kosawa Inside Tsukaguchi Hon 1, Namichi City ■ Inventor Koji Komura Takaichi Tsukaguchi Book 1 Inside the Vessel Research Institute

Claims (4)

[Claims] (1) Place an electrodeless discharge lamp inside the microwave cavity,
In a microwave number light source device that causes an electrodeless discharge lamp to discharge and emit light by a microwave electromagnetic field generated in a cavity of the electrodeless discharge lamp C, a hollow support rod is protruded outward from the lamp wall of the electrodeless discharge lamp C, and a hollow A microwave discharge light source device characterized in that at least a starting rare gas and mercury are sealed therein. (2) The microwave discharge light source device according to claim 1, wherein the hollow support rod also serves as a support portion for an electrodeless discharge lamp. (3) The microwave discharge light source device according to claim 1, wherein the hollow support rod protrudes in a direction toward the power supply port of the microwave cavity. (4) The microwave discharge light source device according to claim 1, wherein the vapor pressure of the mercury sealed in the hollow support rod is equal to or lower than the saturated vapor pressure at room temperature.