Modulation circuit and image display using the same
US6472946B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Jun 5, 2001 |
| Grant date | Oct 29, 2002 |
| Priority date | — |
| Expiry date | Jun 5, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG09G3/2025
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A modulation circuit and an image display able to be set to match the relation of luminance data and a luminance of a LED with a &ggr;-characteristic of a CRT without increasing the bit length of the luminance data or performing pre-processing, such as making corrections to the luminance data. By the A/D converter, the digitalized luminance data is converted into serial data by the controller and is output to pulse width modulation circuits in cascade connection. In each pulse width modulation circuit, a pulse current of a pulse width corresponding to the luminance data is generated, and the LED connected to each pulse width modulation circuit is driven by the current to emit light. Further, the amplitude of the pulse current is variable in accordance with the count of a counter for counting clock signals in the period of the pulse current. As a result, the relation of the time-averaged pulse current flowing in the LED and the luminance data can be made to match the &ggr;-characteristic of a CRT.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.