Method and circuit for reducing emission to grid in field emission displays
US5910791A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 28, 1996 |
| Grant date | Jun 8, 1999 |
| Priority date | — |
| Expiry date | Mar 28, 2016 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2329/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method and a control circuit for controlling a field emission display to reduce emission to grid during turn on and turn off are provided. In an illustrative embodiment, the control circuit includes a threshold detector that receives an input signal proportional to an anode voltage (V.sub.Anode) for the display and produces a high or low output signal dependent on the level of V.sub.Anode. An output low corresponding to a high voltage at the display screen enables a gate element of a pass transistor that controls current flow to the grid. Alternately, an output high corresponding to a low voltage at the display screen enables a pull down transistor that controls discharge of the grid to ground. The control circuit can also include a fault detection circuit for detecting a sharp decrease in the anode voltage and discharging the grid. In an alternate embodiment, the control circuit shorts the emitter sites together during turn on and turn off and provides a high source impedance to restrict current flow to any one emitter site. The high source impedance can be permanent or switchable by a relay or switching circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.