Abstract: An optical storage media and information storage system and method for optically recording information in optically readable form. The DRAW recording medium of the present invention consists of a three layer structure: a transparent substrate; a uniform layer of a dielectric light-responsive material having a threshold energy level at which a physical change in the material occurs; and a highly electrically conductive and highly reflective overcoating on the opposite side of the light-responsive layer from the substrate. The recording method and system allow the concentration of the writing energy to a well defined volume within the thickness of the energy responsive layer or the uniform distribution of the energy throughout the layer by setting up a standing wave within the energy responsive layer by use of the electrically conductive reflecting layer.

Abstract: An optical storage media. The DRAW recording medium of the present invention consists of a three layer structure: a transparent substrate; a uniform layer of a dielectric light-responsive material having a threshold energy level at which a physical change in the material occurs; and a highly electrically conductive and highly reflective overcoating on the opposite side of the light-responsive layer from the substrate. The invention provides a DRAW recording medium which is capable of recording information immediately readable in accordance with the International Electrotechnical Commission optical disc standard for videodiscs.

Abstract: A videodisc recorder signal processing system and a recording method providing programmed control of the amplitude of the secondary (audio channel) carrier signals relative to the primary (video channel) carrier signal during recording. In one embodiment, the amplitude of the two audio carrier signals are varied in accordance with a preprogrammed profile to counteract the MTF effects of the recording system. In another embodiments, the amplitudes of the two audio carriers are varied in accordance with a preprogrammed pattern related to the relative criticality of the audio and video information recorded on the disc. The signal characteristics of the audio channels are improved by increasing the amplitude of the audio carriers. When no audio information exists, the audio carrier signals are substantially eliminated to maximize the quality of the video channel. At other times, the audio carrier signals are decreased to improve the video quality by reducing IM products.

Abstract: A modulator including a voltage controlled oscillator (VCO) having its center frequency stabilized to a reference frequency using a phase locked loop in which the low frequency range is increased by using frequency translation techniques. The VCO output signal is translated relative to the phase locked loop feedback signal so that an increased frequency division ratio can be used in the feedback loop and the effective frequency deviation at the phase comparator can be reduced by an arbitrary factor. This has the effect of increasing the allowable deviation at a given information signal frequency by that arbitrary factor. Likewise, a given deviation can be maintained for input information frequencies which are an arbitrary fraction of the low end cutoff frequencies of conventional modulators.

Abstract: A focus control system with a novel gain control circuit for continually varying the gain of the focus error signal based on the optical characteristics of the medium. As those optical characteristics change to decrease the amount of light available to the focus error detector, the gain of the focus error signal is increased so that the overall gain of the servo loop and the overall response of the servo to a focus error remains constant. This is accomplished by monitoring the optical characteristics of the medium which affect the focus error detector. In a multiple detector system, the outputs of all of the detectors are summed together. The resultant signal is a reflectivity or a transparency signal and is used in a novel circuit for controlling the servo gain.

Abstract: A signal processor and method for frequency compensating the drive signal for an optical modulator in an optical recording apparatus to make the exposure level modulation amplitude on the medium independent of the spatial frequency of the information being recorded. The processor compensates for exposure level modulation roll off at high spatial frequencies due to the finite size of the recording spot by increasing the amplitude of the modulator drive signal at high frequencies. The compensation is preferably the inverse of the modulation transfer function of the recording objective lens.

Abstract: An optical disc structure including two resilient disc members which are bonded together adjacent their outer peripheries and which include an air channel allowing communication between the chamber formed between the discs and the atmosphere. An information layer is formed on the inner surface of at least one of the members. When the members are spun, a pressure differential is caused tending to push the two members apart, thereby assuring that one member will not contact the information layer formed on the other member and that the two members will not be close enough together to cause optical interference.

Abstract: A method for the fabrication of prosthetic dental appliances such as partials, by which the need for the formation of a refractory model is eliminated. According to the method, a resilient plastic appliance is formed by shaping heat-softenable plastic elements to fit a master model and bonding these elements together with an adhesive. The resultant plastic appliance is then removed from the model and may be used as a permanent appliance or as a model for the casting of a permanent appliance.