EPROM package and method of optically erasing
US5300808A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 4, 1992 |
| Grant date | Apr 5, 1994 |
| Priority date | — |
| Expiry date | May 4, 2012 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/1815
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An erasable programmable read only memory (EPROM) package whose storage information can be erased by irradiating with light of a certain wavelength. A semiconductor device (34) with an erasable programmable read only memory is mounted on a circuit carrying substrate (30). Synthetic resin (37) covers the semiconductor device and portions of the circuit carrying substrate to provide a package. A window (39) is formed in the resin to expose the erasable-programmable-read-only-memory circuit to light. The window is cross-polarized and normally opaque to the light and transmits the light when appropriately energized to remove the cross polarization. The light is typically in the ultraviolet frequency, and the window may be made from a liquid crystal material or a solid crystal material such as PLZT. Applying a voltage to the window causes the liquid crystal material in the window to become transparent and allow the EPROM to be erased.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.