Devices and methods for controlling brightness of a display backlight
US9826596B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 16, 2012 |
| Grant date | Nov 21, 2017 |
| Priority date | — |
| Expiry date | Nov 25, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05B45/355
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Devices and methods for controlling brightness of a display backlight are provided. A display backlight controller may control the brightness of the display backlight by changing a duty cycle of a PWM signal that drives the LED current. However, because of LED efficacy and response time, the final output brightness (NITS) may not be linear between 0% to 100%. The disclosed methods may be used to correct the brightness using a predetermined correction factor. Further, the minimum and maximum duty cycle of the output dimming duty cycle may be limited or corrected. In one example, a backlight controller receives an input duty cycle and determines a product of the input duty cycle and a maximum duty cycle to produce a reduced duty cycle. Moreover, the backlight driver may determine a corrected duty cycle using the correction factor. The final output duty cycle and LED current may then be determined.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.