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:
Feb. 18, 2014
Filed:
Jul. 15, 2011
Andrew P. Aitken, Sunnyvale, CA (US);
Andrew P. Aitken, Sunnyvale, CA (US);
Apple Inc., Cupertino, CA (US);
Abstract
Disclosed embodiments relate to techniques for enhancing luminance resolution in a backlight unit. A backlight unit may have light-emitting diode (LED) light sources arranged in strings. In one embodiment, a backlight controller provides enhanced luminance resolution by drive each LED string at either first or second consecutive luminance values corresponding to first and second duty cycles of a pulse width modulation (PWM) signal. The outputs of the LED strings are optically mixed to achieve intermediate luminance values between the first and second luminance values. In another embodiment, a reference voltage is adjusted using slight voltage offsets to achieve intermediate luminance values between the first and second luminance values