# US 4,396,701 A · Highly absorptive dye-containing underlayer for laser recording and data storage media

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- Number: US 4,396,701 A
- Document ID: US4396701A
- Status: Granted
- Kind: A
- Application number: 06/301,230
- Filed: 1981-09-11
- Granted: 1983-08-02
- Earliest claimed: 1981-09-11
- Assignees: Drexler Technology Corporation
- Inventors: Eric W. Bouldin
- Web page: https://patentgrep.com/patent/US4396701A

## CPC

- G11B 7/251: comprising inorganic materials dispersed in an organic matrix
- G03C 8/06: Silver salt diffusion transfer
- Y10S 430/165: Thermal imaging composition
- G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R)
- G03C: PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES (for photomechanical purposes G03F); PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY (photographic processes characterised by the use or manipulation of apparatus classifiable per se in subclass G03B, see G03B; photomechanical production of textured or patterned surfaces G03F; electrophotography, magnetography G03G)
- Y10S: TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS

## Abstract

An underlayer for a laser recording and data storage medium with a light absorption characteristic suited to a recording laser. The underlayer is formed by creating a nuclei layer in a silver-halide photosensitive emulsion layer and then contacting the emulsion layer with a chromogenic reducing agent and a chromogenic dye coupler. The reflective layer may be formed prior to this step by subjecting the nuclei layer to a monobath having a silver-halide solvent and a silver reducing agent until a reflective surface layer of non-filamentary silver particles is formed, or after the step by chemical vapor deposition or sputtering of a reflective metal layer over the underlayer.

## Claims

### Claim 1

A reflective laser recording and optical data storage medium comprising,
a substrate supporting a colloid matrix layer, said colloid matrix layer having a reflective metal surface layer distal to the substrate and a light absorptive underlayer beneath the reflective metal surface layer, formed by black filamentary silver particles and light-absorbing in situ-formed organic dye molecules with an optical density gradient highest proximate to the reflective surface layer.

### Claim 2 (depends on 1)

The medium of claim 1 where said reflective surface layer comprises non-filamentary silver particles and is electrically non-conductive.

### Claim 3 (depends on 1)

The medium of claim 1 where said reflective surface layer comprises a reflective metal layer deposited over the colloid matrix layer.

### Claim 4

A reflective laser recording and optical data storage medium comprising a substrate supporting a light-absorptive colloid matrix layer covered by a vapor-deposited reflective metal layer, said colloid matrix layer composed of black filamentary silver particles and in situ-formed light-absorptive organic dye molecules.

### Claim 5 (depends on 4)

The medium of claim 4 in which the in situ-formed organic dye molecules are absorptive to red and infrared wavelengths.

### Claim 6 (depends on 4)

The medium of claim 4 in which the in situ-formed organic dye molecules are absorptive to blue wavelength.

### Claim 7

A reflective laser recording and optical data storage medium consisting of a thin reflective metal surface layer on an underlayer of colloid on a substrate in which the underlayer comprises light-absorptive black filamentary silver particles and in situ-formed organic dye molecules with an optical density gradient highest proximate to the reflective surface layer.

### Claim 8 (depends on 1)

The medium of claim 1 in which said reflective metal surface layer is electrically non-conductive.

### Claim 9 (depends on 7)

The medium of claim 7 in which said reflective metal surface layer is electrically non-conductive.