Radiation-sensitive record utilizing an annular ring and projections on the disc as spacers between two adjacent discs

摘要

A radiation-sensitive record disc is disclosed having a first disc and a second disc coaxially positioned adjacent the first disc to reinforce the first disc. A first spacer is positioned between the first and second discs for fixedly connecting the discs together and to form an air space between the discs. A recording layer is formed on one surface of the first or second discs within the air space. A second spacer is radially displaced from the first spacer, and positioned between the first and second discs. This second spacer enables the discs to move relative to each other in a radial direction in response to expansion or contraction of at least one of the discs due to changes in temperature, humiduty, atmospheric pressure, etc. In the preferred embodiment the first spacer comprises projections on the inner surface of the second disc, and the second spacer comprises an annular ring which slidably engages a projection on the outer peripheral surface of the second disc member.