Nondestructive readout of a latent electrostatic image formed on an insulating material
US4663526A · kind A · utility
Inventor
Key dates
| Filing date | Apr 3, 1985 |
| Grant date | May 5, 1987 |
| Priority date | — |
| Expiry date | Apr 3, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03G15/221
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus are described for the nondestructive readout of a latent electrostatic image formed on a sheet or layer of insulating material. A sheet or layer of semiconductor material is disposed in relatively close proximity to the insulating material. The latent electrostatic image formed on the insulating material causes a surface depletion layer to by produced by induction at the surface of the semiconductor material. The location and distribution of the accumulated charges on the semiconductor material are read out as analog electrical signals corresponding to the ac surface photovoltage induced on the semiconductor material as the semiconductor material is scanned with a low intensity modulated light beam of appropriate wavelength, the magnitude of the analog signals depending on the local charge density. The analog electrical signals so obtained are then digitized, processed and stored and/or displayed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.