Method of digital grayscale control using modulation of a slow-acting light source
US6262829A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1999 |
| Grant date | Jul 17, 2001 |
| Priority date | — |
| Expiry date | Jul 29, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N2005/7466
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A method of digital grayscale control using light source modulation. First, a light valve, grayscale data, and a light source are provided. The light valve includes a spatial light modulator with at least one pixel. The grayscale data indicates desired grayscale level for the pixel during a frame period. The light source is configured to illuminate the pixel, to generate light with increasing intensity for a rise-time after electric power to the light source is substantially increased, and to generate light with decreasing intensity for a decay-time after electric power to the light source is substantially reduced. The light source may be an arc-lamp. The rise-time and the decay-time taken together may constitute a majority of the frame period. During the frame period, the electric power to the light source is substantially increased and is substantially decreased. Substantially decreasing the electric power to the light source may include turning off the electric power. The frame period is divided into at least four time slices with independent durations so that at least one of the at least four time slices occurs completely during the decay time. This may include selecting the at…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.