Title:
カラーバランスを電気的に調整するLED照明装置
Document Type and Number:
Japanese Patent JP4094952
Kind Code:
B2
Abstract:
The combined light output (chromaticity) of a white light emitting LED luminaire is electronically controlled based on measurements by a single photodiode arranged to measure the light outputs of at least a plurality of the LEDs in the array. This is accomplished by measuring the light output of the LEDs in each color separately in a sequence of time pulses. For an array of red, green, and blue LEDs there are three time pulses in a measuring sequence. During each time pulse, the current for the color being measured is turned off. The response time of a typical photodiode is extremely short, so the measuring sequence can be performed in a sufficiently short time that an-observer will not detect it (e.g. 10 ms). Measured light outputs for the colors are compared to desired outputs, which may be set by user controls, and changes to the power supply for the color blocks are made as necessary. Chromaticity is thus automatically controlled without regard to the factors which may cause it to change. The user inputs permit varying the desired chromaticity to either warm white (more red output) or cool white (more blue output).
Inventors:
Sabramanian Mutu
Chang Ching
Chang Ching
Application Number:
JP2002553873A
Publication Date:
June 04, 2008
Filing Date:
December 12, 2001
Export Citation:
Assignee:
Koninklijke Philips Electronics N.V.
International Classes:
G01J3/50; H05B37/02; F21S8/00; F21S8/04; F21V8/00; F21V9/40; F21V23/04; G08G1/095; H01L33/00; H05B44/00; F21Y101/02; G02B6/00
Domestic Patent References:
| JP2002533870A | ||||
| JP10049074A |
Foreign References:
| WO2000037904A1 |
Attorney, Agent or Firm:
Sadao Kumakura
Fumiaki Otsuka
Shishido Kaichi
Disciple Maru Ken
Ino Sato
Kosaku Sugimura
Fumiaki Otsuka
Shishido Kaichi
Disciple Maru Ken
Ino Sato
Kosaku Sugimura