Abstract: The present invention concerns an arrangement for reading an optically readable carrier on which data is stored in the form of diffractive elements. The data elements each have a plurality of adjacent tracks on the carrier with data elements being positioned on adjacent tracks. The system utilizes an illumination device for projecting a light onto the carrier in order to obtain diffraction of light along the entire length of each of the data elements with an optical arrangement collecting light emerging from the carrier. The optical arrangement is configured and positioned so that light which emerges from the carrier is selectively collected as a function of the angular direction of light from the carrier. The collected light is converted into a data readout signal.

Abstract: The present invention concerns an arrangement for reading an optically readable carrier having a substrate with diffractive tracks with respective longitudinal axes and formed of a succession of irregularities with respect to a smooth reference surface. The irregularities have a width of at most two microns and a variable length equal to or greater than their width and these irregularities have closed contours in the reference surface. The closed contours are diffractive along the entire extent in order to provide for a diffraction of light of a particular light spot focused and centered on a single one of the tracks and substantially occupying the width of the single track. Each of the irregularities has a data element stored along the entire length of the contour and successive irregularities along a track are separated by clearance spaces at least as long as the width of the irregularities in the reference surface.

Abstract: The present invention concerns an arrangement for reading an optically readable carrier with diffractive tracks having a longitudinal axis and contours parallel to the axes. Along each of the contours, the reference surface deviates towards zones which are not coplanar with the reference surface. The tracks are diffractive all along the longitudinal contours in order to diffract a light spot when that light spot illuminates one of the tracks. The track is substantially the same width as the light spot. The contours are such that light emerging from the diffractive track has a spatial distribution which represents the amount of track misregistration between the spot and the axis of the track. The system of the present invention particularly involves a photoelectric detector arranged for collecting radiant energy emerging from the portion of the track which is illuminated by the spot and for detecting an amount and direction of track axis misregistration based upon the spatial distribution.

Abstract: The present invention concerns an arrangement for reading an optically readable light reflective carrier on which data is stored in form of diffractive elements which are deviations from a reference surface. The data elements each have a plurality of adjacent tracks located on the carrier with data elements being positioned on adjacent tracks. The system utilizes an illumination system for projecting a concentrated light spot onto the carrier along a track wherein the diffraction is such that the light emerging from the diffractive track has a spatial distribution representing an amount of track misregistration between the spot and the axis of the track.

Abstract: The present invention concerns an arrangement for reading an optically readable light reflective carrier on which data is stored in the form of diffractive elements which are deviations from a reference surface. The data elements each have a plurality of adjacent tracks located on the carrier with data elements being positioned on adjacent tracks. The system utilizes an illumination device for projecting a concentrated light spot onto the carrier in order to obtain diffraction of light along the entire length of each of the data elements with an optical arrangement collecting light reflected from a carrier in such a way that the light energy which is received when a projected light spot impinges on the reference surface is greater than the light energy received when the projected light spot impinges on a data element.

Abstract: The present invention concerns an arrangement for reading an optically readable light reflective carrier on which data is stored in the form of diffractive elements which are deviations from a reference surface. The data elements each have a plurality of adjacent tracks located on the carrier with data elements being positioned on adjacent tracks. The system utilizes an illumination device for projecting a concentrated light spot onto the carrier in order to obtain diffraction of light along the entire length of each of the data elements with an optical arrangement collecting light reflected from a carrier in such a way that light energy which is received when a projected light spot impinges on the reference surface is greater than the light energy received when the projected light spot impinges on a data element.

Abstract: The present invention concerns an arrangement for reading an optically readable light reflective carrier on which data is stored in the form of diffractive elements which are deviations from a reference surface. The data elements each have a plurality of adjacent tracks located on the carrier with data elements being positioned on adjacent tracks. The system utilizes an illumination means for projecting a concentrated light spot onto the carrier in order to obtain diffraction of light along the entire length of each of the data elements with an optical arrangement collecting light reflected from a carrier in such a way that the light energy which is received when a projected light spot impinges on the reference surface is greater than the light energy received when the projected light spot impinges on a data element.

Abstract: The present invention concerns an arrangement for reading an optically readable light reflective carrier on which data is stored in the form of the diffractive data elements which are deviations from a reference surface. The data elements each have a plurality of adjacent tracks located on the carrier with data elements being positioned on adjacent tracks. The system utilizes an illumination means for projecting a concentrated light spot onto the carrier in order to obtain diffraction of light along the entire length of each of the data elements with an optical arrangement collecting light reflected from a carrier in such a way that the light energy which is received when a projected light spot impinges on the reference surfaces greater than the light energy received when the projected light spot impinges on a data element.

Abstract: The present invention relates to systems for reproducing signals, from a record whose engraved surface contains a recorded track in the form of an embossed print made of diffractive elements, representing the time variation of a pulse time modulated waveform. In accordance with the invention, there is provided a record and an optical read-out device wherein the relief elements carried by the record have a width in the order of the wavelength of the concentrated read-out radiation for determining a spatial variation in the diffracted energy emerging from the illuminated portion of the record, this variation being detected with a photo-electric detector.

Abstract: The present invention relates to systems for reproducing signals, from a record whose engraved surface contains a recorded track in the form of an embossed print made of diffractive elements, representing the time variation of a pulse time modulated waveform. In accordance with the invention, there is provided a record and an optical read-out device wherein the relief elements carried by the record have a width in the order of the wavelength of the concentrated read-out radiation for determining a spatial variation in the diffracted energy emerging from the illuminated portion of the record, this variation being detected with photo-electric elements.

Abstract: The present invention relates to systems for reproducing signals, from a record whose engraved surface contains a recorded track in the form of an embossed print made of diffractive elements, representing the time variation of a pulse time modulated waveform. In accordance with the invention, there is provided a record and an optical read-out device wherein the relief elements carried by the record have a width in the order of the wavelength of the concentrated read-out radiation for determining a spatial variation in the diffracted energy emerging from the illuminated portion of the record, this variation being detected with photo-electric elements.

Abstract: A record system for reproducing information recorded on a record. Information is recorded on a track of the record in the form of an embossed print made of diffractive elements representing the time variation of a pulse modulated waveform. The diffractive elements have a width on the order of the wavelength of a readout light beam. An optical beam readout device provides the concentrated read-out beam and senses a spatial variation in the diffractive energy emerging from an illuminated portion of the track.

Abstract: An apparatus in which the video disk frames are reread while a shutter blocks the film in order to have during the rereading operation the time necessary for advancing the kinescope film without causing violent mechanical stresses. In order to pass from the television standard with 30 frames per second to the cinematographic standard of 24 frames per second, one frame out of five is not recorded on the film and the film advanced without any rereading.

Abstract: This invention relates to the production of information carriers on which the information is recorded along a track; the process of making the information carrier comprises a first step of materializing the track itself before recording any information by forming a groove in an auxiliary layer, the track thus being capable of being optically detected, and a second step of recording the information in a photosensitive layer in contact with the auxiliary layer along the track previously formed.

Abstract: This invention relates to the production of information carriers on which the information is recorded along a track; the process of making the information carrier comprises a first step of materializing the track itself before recording any information by forming a groove in an auxiliary layer, the track thus being capable of being optically detected, and a second step of recording the information in a photosensitive layer in contact with the auxiliary layer along the track previously formed.

Abstract: This invention relates to the production of information carriers on which the information is recorded along a track; the process of making the information carrier comprises a first step of materializing the track itself before recording any information by forming a groove in an auxiliary layer, the track thus being capable of being optically detected, and a second step of recording the information in a photosensitive layer in contact with the auxiliary layer along the track previously formed.

Abstract: A coder designed to receive color television audio video signals where a carrier wave is frequency modulated by the luminance signal and a sub-carrier wave is modulated by time multiplexed chrominance signal and audio signal; the carrier and the sub-carrier waves are linearly mixed and the resultant signal is converted into a multiplex wave formed by a train of length modulated pulses; the sub-carrier frequency is higher than the highest frequency of the luminance signal and the lowest instantaneous frequency of the carrier minus the highest frequency of the luminance signal is at least equal to the sub-carrier frequency; the multiplex signal may be transmitted and registered on a data carrier; and a decoder adapted for cooperating with the coder, for decoding the multiplex signal coming from the transmission channel or the read out data carrier and delivering the audio video signals.

Abstract: The present invention relates to a device designed to constrain the surface of a flexible disc, rotating about an axis, to pass very accurately through a predetermined point. This device is applicable to the read-out of video-signals, and especially of optical video signals, recorded upon a flexible plastic disc. According to the invention, the flexible disc slides on an air film over two fixed surfaces which stabilize its motion, and between two slippers which impose a fixed position upon it.

Abstract: A controlled system for focussing a read-out light beam onto a moving track carrying information, comprising: a focussing objective lens for forming a periodic motion along its optical axis, under the action of a pilot device; a comparator comparing the pilot signal with the envelope of an electrical read-out signal, the comparator thus producing a focussing error signal, and means for applying said signal to the focussing objective lens for correction purposes.