Device and method for controlling a gas discharge lamp, and lighting system with gas discharge lamp and control device

• US 20050146284A1
• Filed: 01/17/2003
• Published: 07/07/2005
• Est. Priority Date: 01/23/2002
• Status: Active Grant

• Current Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Haacke, Michael, Postma, Pieter, Honma, Shin'Ichi
• Granted Patent: US 7,084,581 B2
• Time in Patent Office: Days
• US Class Current: 315/224
• CPC Class Codes: H05B 41/2882 the control resulting from an action on the static converter
• CPC Class Codes: H05B 41/388 for a transition from glow to arc
• CPC Class Codes: Y02B 20/00 Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
• CPC Class Codes: Y10S 315/07 Starting and control circuits for gas discharge lamp using transistors

Abstract

A device and a method for the control of a gas discharge lamp are disclosed. In order to detract as little as possible from lamp life in spite of the luminous flux requirements to be fulfilled during the run-up of the lamp, the lamp is operated with an alternating current in a run-up phase which comprises at least the interval from 1 s to 3 s after lamp ignition, the amplitude of said current rising during the run-up phase. After the rise in the run-up phase, the current may first rise further or remain constant in a transitional phase which preferably follows the former phase, and is subsequently reduced until the lamp enters the stationary operational phase. The time gradient of the current is preferably chosen such here that minimum values for the luminous flux of the lamp are achieved at given moments. Particular advantages are obtained, for example, in the case of Hg-free lamps which are operated with high currents, especially during the run-up.

Claims

1. A device for controlling a gas discharge lamp (10) with

a current supply device (24) for supplying the lamp (10) with an alternating current (IL) of given amplitude,

and a programming unit (μ

C) for providing amplitude values to the current supply device (24) during a run-up phase (B1),

wherein the run-up phase comprises at least the interval from 1 s after ignition of the lamp (10) to 3 s after ignition of the lamp (10), and

wherein the programming unit (μ

C) effectuates a substantially rising gradient in time of the current (IL) during the run-up phase (B1).

2. A device as claimed in claim 1, wherein the time gradient is chosen such that the luminous flux (L) generated by the lamp (10) achieves at least at two given moments assigned minimum valves.

3. A device as claimed in claim 1, wherein the run-up phase (B1) comprises at least the interval from 0.5 s after ignition of the lamp (10) to 4 s after ignition of the lamp (10).

4. A device as claimed in claim 1, wherein the current (IL) rises by at least 30% in the run-up phase (B1) with respect to the value at the start of said phase.

5. A device as claimed in claim 1, wherein the time gradient of the current (IL) in the run-up phase (B1) rises monotonically averaged over time.

6. A device as claimed in claim 1, wherein the current (IL) is an alternating current with a substantially square-wave characteristic in time and a frequency of at least 200 Hz.

7. A device as claimed in claim 1, wherein the current (IL) drops to a stationary value in a transition phase (B2) following the run-up phase (B1).

8. A device as claimed in claim 1, wherein the current (IL) at the start of the run-up phase (B1) amounts to at most 75%, preferably less than 60% of the maximum value that the current assumes in the interval after 1 s after ignition.

9. A lighting system with

a gas discharge lamp (10)

and a control device (22) as claimed in any one of the claims 1 to 8.

10. A lighting system as claimed in claim 9, wherein the gas discharge lamp (10) has a filling free from Hg.

11. A method of controlling a gas discharge lamp wherein

an alternating current (IL) flows through the lamp in a run-up phase (B1) which comprises at least the interval from 1 s after ignition of a lamp (10) to 3 s after ignition of the lamp (10),

wherein the current (IL) is controlled such that its amplitude rises during said run-up phase, and

wherein the time gradient of the current (IL) is chosen such that the luminous flux (L) generated by the lamp (10) achieves at at least to two given moments in time (B1) assigned minimum valves.