Browse Prior Art Database

Capacitive Read Only Memory

IP.com Disclosure Number: IPCOM000094645D
Original Publication Date: 1965-Apr-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 52K

Publishing Venue

IBM

Related People

Ergott, HL: AUTHOR

Abstract

This device employs multilayer printed circuit boards with conductive through-holes to provide a read-only memory.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 79% of the total text.

Page 1 of 2

Capacitive Read Only Memory

This device employs multilayer printed circuit boards with conductive through-holes to provide a read-only memory.

The top exposed surface of the board carries printed word lines WT. These have capacitor plates P formed in them between the plated through-holes H. One intermediate layer of the board carries sense lines S which extend at right angles to the word lines between holes H. Sense lines H provide second capacitor plates so that capacitive coupling exists between each plate P and the sense line beneath it. Another lower intermediate layer comprises a conductive ground plane G which is electrically isolated from through-holes H. The bottom surface carries word lines WB aligned with lines WT and electrically connected to them by plated holes H. No coupling exists between the sense lines and the word line portions on the lower surface of the board because of the shielding effect of the ground plane.

Binary information is recorded in the memory by selectively etching away portions of the upper and lower word lines to provide continuous resultant word lines which are capacitively coupled to some sense lines and not to others. At a coupling point where a binary 1 is to be stored, portion WB extending between holes on the lower surface is etched away. The upper portion WT is left intact to provide capacitive coupling. Where a 0 is to be stored, the upper portion is etched away. The lower portion is left intact. The resultant current pa...