Circuit and a method for controlling a backlight of a liquid crystal display in a portable computer
US5854617A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 9, 1996 |
| Grant date | Dec 29, 1998 |
| Priority date | — |
| Expiry date | May 9, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A backlight luminescence control device for use in a portable computer to control a backlight of a liquid crystal display. When an AC adaptor is not connected to the portable computer, the device senses the voltage level of a DC battery and generates an electrical signal that indicates the status of the battery. From the voltage level of the DC battery, the device ascertains the appropriate luminescence level of a cold-cathode fluorescent backlight lamp (CCFL), automatically controls the brightness of the CCFL through several levels of luminosity, and optimizes the luminescence of the CCFL according to the voltage level available in the DC battery.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.