Pulse width modulated dimming of multiple lamp LCD backlight using distributed microcontrollers
US8212765B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 7, 2007 |
| Grant date | Jul 3, 2012 |
| Priority date | — |
| Expiry date | May 22, 2030 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G2320/064
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a scanning backlight for an LCD display, several backlights (101, 102, 103, 10n) provide a precisely positioned dimming pulse corresponding to a transition point of the LCD screen. The dimming pulse must be variable with video synchronization frequency and dimming duty cycle, which is a performance intensive calculation. One microcontroller performing this operation is limited in scope. By using several ballast controllers (141, 142, 143, 14n), the solution is scalable, in that it is flexible if the number of backlights (101, 102, 103, 10n) changes. Additionally, by using several controllers (141, 142, 143, 14n), added functions can be performed by the ballast controllers (141, 142, 143, 14n).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.