Browse Prior Art Database

Inherently Reflective Optical Media Substrate

IP.com Disclosure Number: IPCOM000105441D
Original Publication Date: 1993-Aug-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 2 page(s) / 70K

Publishing Venue

IBM

Related People

Rossi, RV: AUTHOR

Abstract

A method for obtaining reflection of the information-gathering light beam in optical media is disclosed. This method eliminates the customary metallic reflective layer and replaces it with a surface so shaped as to reflect the light beam.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Inherently Reflective Optical Media Substrate

      A method for obtaining reflection of the information-gathering
light beam in optical media is disclosed.  This method eliminates the
customary metallic reflective layer and replaces it with a surface so
shaped as to reflect the light beam.

      The purpose of this invention is to replace the reflective
layer used in most optical media currently available with a structure
fabricated into the substrate.  The invention is based on the optical
phenomenon of total internal reflection as follows.

      The reflective layer is replaced by ridges, with a roof prism
section, fabricated in the substrate; the prism exhibits total
internal reflection and is oriented so that the light is reflected by
two sides of the prism and back to the source.  As such the prism
operates as a flat reflective layer as wide and as long as the ridge
itself.

      Consider just one section of the reflecting prism, and select
that section which is under the optical stylus (Fig. 1).  Select the
plane forming the section to be perpendicular to the plane of the
media and radial, passing through the center of said media.

      The prism is delimited by sides S1 and S2; the material forming
the prism has a higher coefficient of refraction than the material
outside of S1 and S2 (normally air).  The angle  &alpha  is
90º

      Arrow 1 represents a ray of monochromatic light generated by a
solid state laser as used in the industry.

      Ray tracing of 1 is reflected at point A of side S1 toward
point B of side S2 and back toward the source of lig...