US 9,313,848 B2Granted

Method and device for lighting a space using an LED string

AssigneeKoninklijke Philips N.V.

InventorsMartinus Petrus Creusen, Ralph Kurt

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Abstract

In a method of lighting at least part of a space, a light emitting diode (LED) string is used. The LED string comprises a first LED segment and at least one further LED segment, which are connected in series, each LED segment comprising at least one LED. The LED string is powered by a rectified AC voltage. The first LED segment is powered when the rectified AC voltage is above a first voltage level, and the first LED segment and the further LED segment are powered when the rectified AC voltage is above a second voltage level higher than the first voltage level. The first LED segment is arranged to radiate light to a first volume of the space, and the further LED segment is arranged to radiate light to a second volume of the space, the first volume being at least partly different from the second volume. The first volume may at least partly overlap the second volume.

Claims20

Dependent claims

A method of lighting at least part of a space, using a light emitting diode (LED) string provided on a support, the LED string comprising a first LED segment and at least a second LED segment, which are connected in series, each LED segment comprising at least one LED, the LED string being powered by a rectified dimmable AC voltage,

wherein the first LED segment is powered when the rectified dimmable AC voltage is above a first voltage level, and the first LED segment and the second LED segment are powered when the rectified AC voltage is above a second voltage level higher than the first voltage level,
wherein the first LED segment is arranged to radiate light in a first beam to a first volume of the space, and the second LED segment is arranged to radiate light in a second beam to a second volume of the space, the first volume being at least partly different from the second volume,
wherein one of the following two features is included:
(1) the first LED segment and the first volume are disposed at a first side of the support above the support, and the second LED segment and second volume are disposed at a second side of the support below the support, and (2) the second beam is wider than the first beam, and the second volume includes the first volume, and
wherein the ratio of at least one property of the light generated by the first LED segment and by the second LED segment changes with the dimming level of the rectified dimmable AC voltage.

2 more elements

An apparatus comprising an LED module for lighting at least part of a space, the LED module comprising:

a support;
and
an LED string provided on the support, the LED string comprising a first LED segment and at least a second LED segment connected in series with each other, wherein each LED segment comprises at least one LED;
wherein the LED string is adapted to be powered by a rectified dimmable AC voltage;
wherein the first LED segment is adapted to be powered when the rectified AC voltage is above a first voltage level, and the first LED segment and the second LED segment are adapted to be powered when the rectified AC voltage is above a second voltage level higher than the first voltage level,
wherein the first LED segment is arranged to radiate light in a first beam to a first volume of the space, and the second LED segment is arranged to radiate light in a second beam to a second volume of the space, the first volume being at least partly different from the second volume,
wherein one of the following two features is included:
(1) the first LED segment and the first volume are disposed at a first side of the support above the support, and the second LED segment and second volume are disposed at a second side of the support below the support, and (2) the second beam is wider than the first beam, and the second volume includes the first volume, and
wherein, the ratio of properties of the light generated by the first LED segment and by the second LED segment changes with the dimming level of the rectified dimmable AC voltage.

6 more elements

Dependencies are inferred from the claim text.

Facts

Application: 14/004,745Filed 12 Mar 2012
Priority: EP 1115881918 Mar 2011
Published: US 2013/0342120 A126 Dec 2013
Granted: 12 Apr 2016
Term ends: Not estimatedThe source records don’t support an estimate.

Classification5 codes

H05B 45/48
With an active control inside an LED matrix: having LEDs organised in strings and incorporating parallel shunting devices
H05B 45/31
Driver circuits: phase-control circuits
H05B 45/20
Circuit arrangements for operating light-emitting diodes [LED]: controlling the colour of the light
H05B 45/325
Pulse-control circuits: pulse-width modulation [PWM]