Transmissively read quad density optical data system

• US 4,786,792 A
• Filed: 10/31/1986
• Issued: 11/22/1988
• Est. Priority Date: 10/12/1983
• Status: Expired due to Term

• Current Assignee: LaserCard Corp. (Assa Abloy AB)
• Original Assignee: Drexler Technology Corporation (Assa Abloy AB)
• Inventors: Pierce, Gerald A., Buxton, James L.
• Primary Examiner(s): TRAFTON, DAVID
• Application Number:
  US06/925,197
• Time in Patent Office: 753 Days
• Field of Search: 235/456, 235/470, 235/455, 235/494, 235/454, 250/569, 369/46
• US Class Current: 235/456
• CPC Class Codes: G06K 19/06037 multi-dimensional coding
• CPC Class Codes: G06K 19/14 the marking being sensed by radiation
• CPC Class Codes: G06K 7/14 using light without selection of wavelength, e.g. sensing reflected white light G06K7/10831 - G06K7/1097 take precedence
• CPC Class Codes: G11B 7/0033 with cards or other card-like flat carriers, e.g. flat sheets of optical film
• CPC Class Codes: G11B 7/013 for discrete information, i.e. where each information unit is stored in a distinct discrete location , e.g. digital information formats within a data block or sector
• CPC Class Codes: G11B 7/085 with provision for moving the light beam into, or out of, its operative position or across tracks, otherwise than during the transducing operation, e.g. for adjustment or preliminary positioning or track change or selection
• CPC Class Codes: G11B 7/13 Optical detectors therefor

Abstract

An optical data storage and retrieval system using a length of optical recording material in which data in the form of microscopic spots is disposed in cells forming a regularly spaced grid. While the material is being moved in a lengthwise direction by a transport, rows of cells are being read by a linear CCD array, one row at a time. A servo system advances the material so that successive rows can be read, while a second servo adjusts the position of the material in the crosswise direction for proper alignment with the CCD array.

Claims

1. An optical data storage and retrieval system comprising,

an optical data storage medium having optically readable digital data encoded by microscopic spots in specified data cell positions on said medium thereby changing transmissivity of the medium, said data cell positions forming a grid with perpendicular, contiguous yet non-overlapping rows and columns of cell positions, said columns aligned with the length of said medium, and

a linear CCD array aligned perpendicular to said columns of cell positions on a side of said medium opposite a light source, said array having a plurality of fixed position detector cells imaging each specified data cell position in a row of cells, wherein at least two detector cells image a specified data cell position, with groups of detector cells simultaneously imaging a plurality of cell positions.

2. The system of claim 1 wherein said storage medium comprises a strip of opaque optical data storage material with transparent microscopic spots.

3. The system of claim 2 wherein said strip of optical data storage material is mounted on a wallet-size card.

4. The system of claim 1 wherein a first group of rows is separated from a second group of rows by a lengthwise optically absorptive line.

5. The system of claim 1 further comprising a first servo for adjusting the crosswise position of the storage medium relative to the CCD array.

6. The system of claim 5 further comprising a second servo for incrementally advancing the lengthwise position of the storage medium.

7. An optical data storage and retrieval system comprising,

a data card having a length and a width with a strip of an optical recording medium thereon, said strip having microscopic data spots aligned in contiguous data cell positions forming a grid with non-overlapping elements in said lengthwise and widthwise directions,

a data readout head having a linear photodetector cell array disposed on a side of said data card opposite a light source to transmissively read data spots on the strip in a direction across the width of said card, wherein said readout head has a plurality of detector cells of said linear detector cell array for each cell position in a row of cell positions, with groups of detector cells simultaneously imaging a plurality of cell positions and

card transport means for advancing said card relative to said head in a direction parallel to the length of said card.

8. The system of claim 7 further comprising a second servo for adjusting the crosswise position of the medium relative to the CCD array.

9. A data card read system comprising,

a data card having contacting, yet non-overlapping parallel rows of data cells arranged in groups of contacting parallel columns, each data cell capable of holding a single bit of data approximately the size of a laser beam diameter, each group of columns of data cells spaced from a neighboring group of columns, thereby forming parallel bands of data,

a card transport having means for moving the card,

a beam source means for directing a radiation beam onto the card and beam detector means on an opposite side of said data card from said beam source means for reading said radiation beam after transmission through the card, said beam detector means capable of simultaneously reading a row of data cells, wherein said beam detector means include a linear array of fixed position detectors, wherein at least two detectors read each data cell, with groups of detector cells simultaneously imaging a plurality of cell positions, and

card transport means for advancing the card relative to the beam source and the beam detector means so that successive rows of data can be read.

10. The apparatus of claim 9 wherein parallel bands of data are separated by parallel, absorptive lines.

11. The apparatus of claim 9 wherein each row of data cells has track marks at opposed ends, said track marks identifying a row.

12. The apparatus of claim 9 wherein said detector means comprises a linear array having a width greater than a row of data, said linear array having detector cells imaging data in a row plus some data from rows in neighboring bands.

13. A data card comprising,

a substrate capable of supporting an optical data storage medium, and

an elongated data storage medium on the substrate having a rectangular non-overlapping array of contiguous storage cells, including a length dimension and a width dimension, some of the storage cells having data spots therein of microscopic size, the remaining storage cells being empty, said spots being mainly transmissive of light in comparison to the surrounding field which is mainly opaque to light, the data being arranged in tracks along the widthwise direction, at least one end of each track having spots marking the presence of the track, each of the storage cells in a track having a size capable of being imaged by a plurality of adjacent detector cells in a linear array.

14. The data card of claim 13 wherein said rectangular array of storage cells is divided into a plurality of bands by parallel, absorptive lines, each band containing a plurality of tracks.

15. The data card of claim 13 wherein the size of said spots is between 1 to 35 microns along an edge or a diameter.

16. The data card of claim 13 wherein at least some of said data spots are contiguous in both lengthwise and widthwise directions.

17. The data card of claim 13 wherein said spots are photographically prerecorded in a photosensitive emulsion having an optically contrasting field surrounding the spots, said emulsion forming said storage medium.