Wea Manufacturing, Inc.

Anthony E Pietrzykoski

Christopher J Cookson

Charles M Mecca

Floyd L Goss, Jr

Richard Marquardt, Jr

Daniel M Pindzola

Scott Smith

Deborah H Carey

Howard Price

John L Orehotsky

Floyd Goss

A double sided (or higher multiple sided) data storing compact disc for optically recorded data has data surfaces that are separated by a thin film of wavelength selective material that passes light of one frequency and reflects light of a second (or multiple) frequency. The thin film either passively relies upon the inherent interference between light signals reflected from its upper and lower surfaces or is an active material that reflects light of one frequency and transmits light of a second frequency. A further aspect of the present invention is the method for the manufacture of such a multi-surfaced disc.

Multiple layer optical recording medium for use with two different

A system for testing compact discs having audio or video information and time subcode information indicating the elapsed time from the beginning of the audio, video or data information thereon in which three microprocessors respectively monitor the HF signal, the radial tracking signal and the decoder digital flags produced by a CD player to produce error signals indicating HF dropout, HF low, modulation amplitude, radial tracking, Burst, Bler, and uncorrectable errors and in which a computer having a memory responds to the time signal produced by the player periodically to transfer the contents of the microprocessors to the memory together with the time of transfer and to reset the microprocessors, thus to record errors and to locate the positions thereof on the disc in terms of the time subcode information. Initially an eccentricity test is performed and the entire test is stopped if the eccentricity is excessive. The computer is programmed to display the test results in various formats.

System and methods for measuring and correcting for overshoot in a high

Apparatus for counting compact discs stacked on a spindle with outer portions of adjacent discs normally separated by gaps formed by central bosses of the discs in which the stack is moved vertically through the space between transmitting optics which produce a pair of vertically spaced beams having a space therebetween equal to the distance between a pair of adjacent gaps of the stack and receiving optics including a detector which produces pulses in response to radiation from said beams which transverse the gaps. The time between a pair of successive pulses is measured and the second pulse of the pair is counted as two pulses when the measured time exceeds a predetermined time. The apparatus is arranged to operate with either of two types of spindles.

Compact disc counter arranged to minimize counting errors having a pair

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Plains, PA, United States of America

Anthony E Pietrzykoski