Patent ID: 7570246
Filing Date: 2009-08-04
Classification: H04B

Abstract:
1. An electronic device comprising a display and a pulse-width-modulated (“PWM”) light-emitting diode (“LED”) backlight configured to adjust a brightness of the display, comprising: a data input configured to receive data therein; a buffer operably connected to the data input and configured to store data received from the data input; a pulse generator configured to generate a pulse; a signal generator configured to generate a carrier signal; a modulator operably coupled to the pulse generator, the buffer, and the signal generator, the modulator being configured to receive data from the buffer and modulate the carrier signal in accordance with the data received from the buffer to produce a modulated carrier signal; an adder configured to add the modulated carrier signal to the pulse to produce a modulated pulse; and an LED driver operably connected to the adder and configured to receive the modulated pulse therefrom, the LED driver further being operably connected to LEDs disposed within the PWM LED backlight and configured to drive the PWM LED backlight LEDs using the modulated pulse such that an average brightness of the display is essentially the same in respect of an unmodulated pulse being provided thereto; wherein the PWM LED backlight is configured to produce a modulated optical signal in accordance with the data that is suitable for use in a visible optical communications system.