The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 26, 2019
Filed:
Oct. 29, 2018
Melexis Technologies NV, Tessenderlo, BE;
Raik Frost, Efurt, DE;
Thomas Freitag, Plaue, DE;
MELEXIS TECHNOLOGIES NV, Tessenderlo, BE;
Abstract
A device having a light emitting diode (LED) of a red-green-blue type, a pulse width modulation (PWM) control, a current supply, and a microcontroller. The RGB LED device arranged for setting a PWM duty cycle using the PWM control and for supplying to the LED either a current of a first value or a current of a second value higher than the first value from the current supply. A method for calibrating the LED of the RGB LED device by measuring sets of tristimulus values when the PWM duty cycle and currents are applied, and calculating from the measured tristimulus values parameters to express colour intensity as a function of PWM duty cycle under the applied current. A method for operating the RGB LED device where calibration parameters linked to the use of a current having a low value and calibration parameters linked to the use of a high current value are determined and used to account for a possible working point shift when switching between the two currents. The calibration parameters including the parameters calculated from sets of tristimulus values to express colour intensity as a function of PWM duty cycle for the applied currents.