Illumination device and method for calibrating an illumination device over changes in temperature, drive current, and time
US10595372B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 2016 |
| Grant date | Mar 17, 2020 |
| Priority date | — |
| Expiry date | Dec 22, 2036 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B47/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An illumination device and method is provided herein for calibrating individual LEDs in the illumination device, so as to obtain a desired luminous flux and a desired chromaticity of the device over changes in drive current, temperature, and over time as the LEDs age. The calibration method may include subjecting the illumination device to a first ambient temperature, successively applying at least three different drive currents to a first LED to produce illumination at three or more different levels of brightness, obtaining a plurality of optical measurements from the illumination produced by the first LED at each of the at least three different drive currents, obtaining a plurality of electrical measurements from the photodetector and storing results of the obtaining steps within the illumination device to calibrate the first LED at the first ambient temperature. The plurality of optical measurements may generally include luminous flux and chromaticity, the plurality of electrical measurements may generally include induced photocurrents and forward voltages, and the calibration method steps may be repeated for each LED included within the illumination device and upon subjecting t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.