Illuminant and operating method therefor

Abstract

The invention relates to an illuminant having a gas volume and a coaxial HF energy coupling device for the excitation thereof using surface waves. It is provided in this case that the coaxial HF energy coupling device (3) has a central conductor (4) guided in the gas volume (2).

Claims

1. An illuminant comprising; a gas volume contained in a glass bulb, said glass bulb forming a gas lighting chamber, an HF energy injection device for exciting the gas volume with surface waves and having a coupling structure which comprises a coaxial jacket, a front plate and a coupling slot for impressing the surface waves, said HF energy injection device further having a central conductor that is coupled into the gas volume, is isolated galvanically from the coupling structure and from the gas volume and is arranged on a longitudinal axis of the coaxial jacket, and said central conductor projecting beyond the coaxial jacket at a distance from the coupling structure, the central conductor in the region projecting beyond the coaxial jacket being located within the gas volume, in order therefore, during operation, to form a surface wave extending along the central conductor via the coupling structure of the coaxial HF energy injection device so as to set the gas volume into the plasma state.

2. An illuminant according to claim 1 wherein the gas volume is a high-pressure gas volume and is for illumination with high brilliance.

3. An illuminant according to claim 1 wherein the gas volume is a low-pressure gas volume and the lighting means is for one of UV generation and illumination.

4. An illuminant according to claim 1 wherein the gas volume is a low-pressure gas volume and the lighting means is for UV generation purposes and illumination purposes.

5. An illuminant according to claim 1 wherein the gas volume is a medium-pressure gas volume and is to generate one of biological and chemically active radiation.

6. An illuminant according to claim 1 wherein the gas volume is a medium-pressure gas volume and is to generate biological and chemically active radiation.

7. An illuminant according to claim 1 wherein the gas volume is for water disinfection with UV radiation.

8. An illuminant according to claim 1 wherein the center conductor is constructed and arranged for feeding and/or conducting energy in the fundamental mode.

9. An illuminant according to claim 1 wherein the gas volume is excited with non-resonant energy.

10. An illuminant according to claim 1 wherein the HF energy injection device is constructed and arranged to inject pulsed energy and/or broadband HF energy and/or comprises a pulsed or broadband HF energy source.

11. An illuminant according to claim 1 wherein the illuminant is constructed and arranged for self-regulation by power reflection.

12. An illuminant according to claim 1 wherein the gas lighting chamber is substantially free of any shielding.

13. An illuminant according to claim 1 wherein the front plate defines one side of a coupling chamber of the coupling structure with the coupling chamber being substantially cylindrical in shape and having a central coupling chamber axis.

14. An illuminant according to claim 13 wherein the coupling slot is formed in the front plate and has a coupling slot axis that is coincident with the central coupling chamber axis.

15. An illuminant according to claim 14 wherein the central conductor extends a major length of the glass bulb.

16. An illuminant according to claim 15 wherein the coupling chamber has a length as measured along the central coupling chamber axis that is less than a diameter of the coupling chamber.

17. An illuminant according to claim 1 wherein the front plate defines one side of a coupling chamber of the coupling structure with the coupling chamber having a central coupling chamber axis, wherein the coupling slot is formed in the front plate and has a coupling slot axis that is coincident with the central coupling chamber axis, wherein the coaxial jacket also has a coaxial jacket axis coincident with the central coupling chamber axis, and wherein a diameter of the coaxial jacket is less than a diameter of the coupling chamber.

18. An illuminant according to claim 17 wherein the diameter of the coaxial jacket is on the same order as a diameter of the coupling slot.

19. An illuminant according to claim 17 wherein the diameter of the coupling slot is less than the diameter of the coupling chamber.

20. A method for operating a lighting means according to claim 1, wherein the HF energy is injected in a broadband and/or pulsed manner.

Description

DESCRIPTION OF THE DRAWINGS

(1) The invention will be described on the basis of the drawing hereafter only as an example. In the FIGURE

(2) FIG. 1 shows a coupling structure for an illuminant of the present invention.

DETAILED DESCRIPTION

(3) According to FIG. 1, an illuminant 1, which is designated in general with 1, comprises a gas volume 2 and a coaxial HF energy coupling device 3 for exciting the gas volume 2 using surface waves, wherein the coaxial HF energy coupling device 3 has a central conductor 4 guided in the gas volume 2.

(4) The illuminant 1 is filled in the present case as a low-pressure illuminant with a gas of 30 mbar here, using argon here, for example. The gas volume 2 is enclosed in an elongated glass bulb 2a, which is only indicated by dashed lines in FIG. 1. The glass bulb does not extend up into the interior of the coupling structure 3, but rather just only up close to it. A short-circuit of the microwave energy to be coupled to the inner conductor by the plasma is thus prevented. The central conductor 4 is located in this glass cylinder 2a, galvanically isolated from the further coupling structure 3.

(5) The coupling structure 3 is formed in the present case, except for the central conductor 4, per se as described in U.S. Pat. No. 4,049,940. A similar coaxial energy feed line 3a is provided here, which is connected in the interior of a coupling chamber 3b with a capacitive coupling plate 3c, which regionally approaches closely to a coaxial jacket 3d. The coaxial jacket 3d has an axis, on which the central conductor 4 extends and accordingly forms a coaxial HF energy coupling device with the central conductor. Furthermore, the coupling structure 3 has a coupling slot 5 for applying the surface wave and a front plate 6. As the comparison to U.S. Pat. No. 4,049,940 shows, the present invention therefore differs in particular from the prior art by way of the additional central conductor 4. This intellectual property is moreover incorporated in its entirety for the purposes of disclosure.

(6) The arrangement is operated as follows:

(7) Energy is conducted via the coaxial feed line and the coaxial coupling toward the gas volume 2 via the coaxial feed line 1 from an HF energy source (not shown), which can be formed in the remaining part of the illuminant or separately. The capacitive coupling couples energy into the coaxial structure made of coaxial jacket 3d and central conductor 4 to relay energy in a coaxial fundamental mode.

(8) By way of the supplied energy, a surface wave forms along the central conductor, which extends along the central conductor beyond the coupling structure and therefore also extends into the region of the elongated glass bulb outside the actual coupling structure, i.e., beyond the front plate 6, and the gas volume is set into the plasma state.

(9) The coupling is performed without resonance conditions having to be maintained, so that pulsed operation is readily possible. Measurements have shown that no significant microwave power is emitted.

(10) While in the present case the use of a bulb made of glass was described, this is not absolutely necessary. In particular, but not exclusively, for example, in the case of high-pressure lamps, the use of suitable ceramics also comes into consideration. The use of an internal conductor which is not galvanically isolated also rather comes into consideration for high-pressure illuminants having ceramic insulators.

(11) In summary, an illuminant and a method for operating an illuminant were therefore described, in the case of which high-frequency waves are coupled into a gas volume to generate and maintain a plasma with only slight shading, a small construction is achieved, broadband transmission for high-frequency waves in the component is ensured, the intrinsic consumption or idle consumption is very low, and the high-frequency wave can be readily transported into the interior of the illuminant.