Controlling pixel brightness in a field emission display using circuits for sampling and discharging
US5856812A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1996 |
| Grant date | Jan 5, 1999 |
| Priority date | — |
| Expiry date | Apr 24, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2329/00
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A flat panel display, such as a Field Emission Display ("FED"), is disclosed having a current control circuit. Input into the display, initially, is an analog signal having an amplitude. In one embodiment, the current control circuit includes a converter for converting the analog input signal to a sawtooth signal having a height and width. Then, the level of the sawtooth signal is compared to a voltage level to establish a pulse width of an emitter current. The emitter current is thus controlled by a pulse width modulation approach. In another embodiment, the current control circuit traps a column voltage on a parasitic capacitance. The trapped voltage then controls the gate of a transistor to control current flow from the emitter set to ground.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.