Optical High Density Direct Access Storage Device
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2005-Feb-15
This article describes an optical Direct Access Storage Device (DASD). Two methods of position control are used to achieve high density. It has minimal moving parts and this motion is over a small area. The figure shows an exploded view of the DASD unit. The light source layer 1 is a 256 by 256 pixel array of concentrated light. This can be accomplished with a directed laser beam or by using a backlit LCD screen. For simplicity, the figure shows this as an 8 by 8 array. The active area is 2 inches by 2 inches. Each pixel of the light source array concentrates light in an 8 thousandths of an inch square area. The pin hole grid 2 is composed of a 256 by 256 array of pin holes. Each pin hole is approximately 30 millionths of an inch in diameter. This pin hole grid is shown as an 8 by 8 array in the figure.