Method and apparatus for reading information stored in a fluorescent multilayer information carrier
OwnerEugene Levich, Boris Chernobrod +1inventors
InventorsEugene Levich, Boris Chernobrod, Anatolii Dovgan
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Abstract
An apparatus and method for reproducing information stored in a fluorescent multilayer information carrier. The apparatus utilizes auto-focusing and auto-framing techniques when reading the information to enable parallel reading from uniformly moving carrier. To avoid discontinuity in motion, an actuator with an objective lens performs periodic motion following a specific moving information page and, after the end of reading of this page, returns back to follow the next page.
Claims21
An apparatus for reproducing optical information stored in a fluorescent multilayer information carrier, in which the entire information field is formed by a plurality of sub-fields, the apparatus comprising:
- (a) a light source generating a light beam of incident light having predetermined frequency range selected so as to excite fluorescence in the information carrier and produce fluorescent information signals indicative of the information stored in the information carrier;
- (b) a detector unit comprising a photosensitive matrix for detecting the fluorescent information signals and generating electrical output indicative thereof, which is to be processed to reproduce the stored information;
- (c) an optical readout head designed to provide a predetermined geometry of the incident light beam to illuminate an area of the information carrier corresponding to a frame of the information sub-field, thereby enabling frame-by-frame imaging of the information sub-field onto the photosensitive matrix;
- (d) a light directing assembly for directing the light beam generated by the light source towards the readout bead and directing the information signals to the detector unit;
- and
- (e) a drive system operable to provide relative displacement between the optical readout head and the information carrier along a predetermined pass, thereby enabling auto-focusing of the incident light beam from layer to layer and precise positioning of the optical readout head relative to the information carrier within a plane parallel to the surface of the information carrier so as to provide a predetermined position of an image of each information sub-field on the photosensitive matrix.
A method for reproducing optical information stored in a fluorescent multilayer information carrier, in which the entire information field is formed by a plurality of sub-fields, the method comprising the steps of:
- (i) generating a light beam of incident light having a predetermined frequency range selected so as to excite fluorescence in the information carrier and produce
- fluorescent information signals indicative of the information stored in the information corner;
- (ii) directing the light beam through an optical readout head having an objective lens with all actuator and designed to provide a predetermined geometry of the incident light beam to illuminate an area of the information carrier corresponding to a frame of the information sub-field, and directing the information signals to a photosensitive matrix, thereby enabling frame-by-frame imaging of the information sub-field onto the photosensitive matrix;
- (iii) detecting the information signals and generating electrical output indicative of the information stored in the information carrier;
- (iv) selectively driving a movement of the objective lens with the actuator along an axis perpendicular to the surface of the carrier to focus the incident light from layer to layer, and selectively driving relative displacement between the optical readout head and the information carrier along a predetermined pass to enable precise positioning of an image of each information sub-field on the photosensitive matrix, and to scan successive sub-fields.
Dependencies are inferred from the claim text.