Dimmable discharge lamp for dielectrically impeded discharges

{
  "publication_number": "US6376989B1",
  "country": "US",
  "kind": "B1",
  "title": "Dimmable discharge lamp for dielectrically impeded discharges",
  "abstract": "A description is given of a method for dimming discharge lamps with dielectrically impeded discharges. A continuous or discontinuous power control can be effected by influencing an electric parameter of a pulsed active-power supply and by means of a suitable electrode structure.",
  "claims": [
    "1. An operating method for a discharge lamp having a discharge vessel, containing a discharge medium, an electrode arrangement with an anode (2) and a cathode (1), and having a dielectric layer (4) between at least the anode (2) and the discharge medium, the electrode arrangement (1, 2) being inhomogeneous along a control length (SL) in a way which varies a burning voltage, by virtue of the fact that it defines along the control length (SL) a discharge spacing varying monotonically at least in a local mean value, characterized in that it holds for the quantitative ratio between a difference between a maximum arcing distance d max between the electrodes (1, 2) in the control length (SL) and a minimum arcing distance d min between the electrodes (1, 2) in the control length (SL) and this control length (SL) that: (d max −d min)/SL≦0.6, and an electric parameter of the power supply of the discharge lamp is varied during operation in order to control the power of the discharge lamp.",
    "2. The operating method as claimed in claim 1, in which the inhomogeneity additionally consists in a variation of the thickness of the dielectric layer (4).",
    "3. The operating method as claimed in claim 1, in which the electrodes (1, 2) of the discharge lamp have a number of control lengths (SL) in series.",
    "4. The operating method as claimed in 1, in which the electric parameter of the power supply is varied in a continuous way in order to dim the discharge lamp.",
    "5. The operating method as claimed in 1, in which the electric parameter is a voltage amplitude of a pulsed active-power injection.",
    "6. The operating method as claimed in claim 1, in which the electric parameter is an edge rise steepness of a pulsed active-power injection.",
    "7. The operating method as claimed in claim 1, in which the electric parameter is a dead time of a pulsed active-power injection.",
    "8. The operating method as claimed in 1, in which the electric parameter is a pulse duration of a pulsed active-power injection.",
    "9. The operating method as claimed in claim 1, in which the electric parameter is a pulse repetition frequency of a pulsed active-power injection.",
    "10. The operating method as claimed in claim 1, in which at least one of the electrodes (1, 2) has a sinusoidal shape.",
    "11. The operating method as claimed in claim 1, in which the inhomogeneity additionally consists in a variation of the anode width.",
    "12. A discharge lamp having a discharge vessel, containing a discharge medium, an electrode arrangement with an anode (2) and a cathode (1), and having a dielectric layer (4) between at least the anode (2) and the discharge medium, designed for a method according to claim 11, in which the electrode arrangement (1, 2) along the control length (SL) defines a discharge spacing which varies monotonically at least in a local mean value.",
    "13. The operating method as claimed in claim 1, in which a number of cathode points for local field forcing are present along the control length (SL), these points of local field forcing defining a monotonically graded sequence of different burning voltages.",
    "14. The operating method as claimed in claim 13, in which the number of individual discharge structures (3) varies in conjunction with the power control in the control length (SL), each of the discharge structures (3) being respectively arranged at one of the points of local field forcing.",
    "15. The operating method as claimed in claim 1, in which the discharge volume varies in conjunction with the power control within the control length (SL).",
    "16. The operating method as claimed in claim 15, in which the change in discharge volume is implemented in conjunction with the power control by spreading a discharge structure (3) like a curtain within the control length (SL).",
    "17. The operating method as claimed in claim 15, in which the change in discharge volume is implemented in conjunction with the power control by producing a controllable number of individual discharges within the control length.",
    "18. The operating method as claimed in claim 1, in which it holds that: (d max −d min)/SL≦0.5, and with particular preference (d max −d min)/SL≦0.4.",
    "19. The operating method as claimed in claim 1, in which it holds for the quantitative ratio between the minimum arcing distance d min and the maximum arcing distance d max between the electrodes (1, 2) in the same control length (SL) that: 0.3<d min /d max <0.9, preferably 0.4<d min /d max <0.9, with particular preference 0.5<d min /d max <0.9.",
    "20. The operating method as claimed in claim 1, in which layers covering the cathode (1) have a graininess of 8 μm or less.",
    "21. The operating method as claimed in claim 1, in which the cathode (1) is free from fluorescent layers.",
    "22. The operating method as claimed in claim 1, in which at least one of the electrodes (2; 10; 12; 13) has a sawtooth shape.",
    "23. The operating method as claimed in claim 22, in which the sawtooth shape of the electrodes (10; 12; 13) is formed by an alternating sequence of short steep and long correspondingly less steep ramps.",
    "24. The operating method as claimed in claim 22, in which an electrode with a sawtooth shape and an electrode which is the mirror image thereof are arranged in pairs and parallel to one another.",
    "25. The operating method as claimed in claim 24, in which two parallel linear electrodes (11) are arranged between two adjacent electrode pairs (10) with a sawtooth shape.",
    "26. The operating method as claimed in claim 1, use being made of a ballast with an energized primary circuit (P), a secondary circuit (S) containing the discharge lamp (L), and of a transformer (T) connecting the primary circuit (P) to the secondary circuit (S), the ballast being designed for applying to the discharge lamp (L) external voltages (U L) with signs which alternate from voltage pulse to voltage pulse.",
    "27. The operating method as claimed in 26, in which the primary circuit is supplied from an alternating-current source which charges two storage capacitors alternately by half period, each storage capacitor being respectively assigned to one of the two current directions.",
    "28. The operating method as claimed in claim 26, in which the direction of the current (I W1), on the side of the primary circuit, in the transformer (T) alternates from voltage pulse to voltage pulse.",
    "29. The operating method as claimed in claim 28, in which the transformer has two windings (W 1) on the side of the primary circuit which are respectively assigned to one of the two current directions.",
    "30. The operating method as claimed in claim 29, in which the primary circuit has two switches (T Q) which in each case clock the current through one of the two windings (W 1).",
    "31. A lighting system having a discharge lamp having a discharge vessel, containing a discharge medium, an electrode arrangement with an anode (2) and a cathode (1), and having a dielectric layer (4) between at least the anode (2) and the discharge medium, the electrode arrangement (1, 2) being inhomogeneous along a control length (SL) in a form which varies a burning voltage, by virtue of the fact that along the control length it defines a discharge spacing which varies monotonically at least in a local mean value, and having a ballast, characterized in that it holds for the quantitative ratio between a difference between a maximum arcing distance d max between the electrodes (1, 2) in the control length (SL) and a minimum arcing distance d min between the electrodes (1, 2) in the control length (SL) and this control length (SL) that: (d max −d min)/SL≦0.6, and the ballast has a power control device for controlling the power of the discharge lamp by varying an electric parameter of the power supply of the discharge lamp."
  ],
  "description_excerpt": "The present invention relates to an operating method for a discharge lamp which is designed for dielectrically impeded discharges. For this purpose, the discharge lamp has a discharge vessel filled with a discharge medium, and at least one anode and at least one cathode. A dielectric layer is provided at least between the anode and the discharge medium, in order to produce dielectrically impeded discharges.\n\nThe terms anode and cathode are not to be understood in this application such that the invention is limited to unipolar operation. In the bipolar case, there is, at least electrically, no difference between anodes and cathodes, and so the statements for one of the two electrode groups then hold for all electrodes.\n\nAs promising fields of application for the discharge lamps considered here, mention may be made by way of example of the backlighting of flat display screen systems, or the backlighting of signal devices and signal lamps themselves. Reference is made in a supplementary fashion regarding the two last-named points to the disclosure content, hereby referred to, of EP-A-0 926 705. Furthermore, this invention is also suitable for lamps such as the copier lamp, represented in DE-A-197 18 395, with internal electrodes, and to the linear lamp, described in German application 198 17 475.6, with external electrodes. The disclosure content of the cited applications is respectively referred to hereby.",
  "cpc": [
    "H01J 61/0672",
    "H01J 61/06",
    "Y10S 315/07"
  ],
  "ipc": [
    "H01J 61/067",
    "H01J 65/00",
    "H05B 41/24",
    "H05B 41/392",
    "H05B 41/40"
  ],
  "assignees": [
    "Patent Treuhand Gesellschaft fuer Elektrische Gluehlampen mbH"
  ],
  "inventors": [
    "Frank Vollkommer",
    "Lothar Hitzschke"
  ],
  "filing_date": "1999-09-13",
  "publication_date": "2002-04-23",
  "grant_date": "2002-04-23",
  "priority_date": "1998-09-29",
  "application_number": "US-80613501-A",
  "family_id": "7882702",
  "cited_by_count": 12,
  "citations": [
    "GB2139416A",
    "US4584501A",
    "DE4311197A1",
    "WO1994023442A1",
    "US5760541A",
    "DE19628770A1",
    "US6040662A",
    "DE19817479A1"
  ]
}