Optical disc structure, method and apparatus physically optimized for writing and reading with a single wavelength

Claim 2

A record element adapted for improved real-time writing and reading of high density information with light of a given wavelength, said element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface; (a) said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a first reflectance minimum having a high depth of modulation; and (b) said stratum having a nominal thickness sufficiently greater than the thickness corresponding to said first reflection minimum to effect reflection of a significant minor proportion of light of said given wavelength.

Claim 3

The invention defined in claim 1 wherein said nominal thickness is proximate a transition, from a zone of gradual slope to a zone of rapid slope, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby decreases in thickness of said recording stratum during deformation recording will yield substantial differences in relative phase shift between reading light of said given wavelength reflected from said record element.

Claim 4

The invention defined in claim 2 wherein the optical constants of said recording layer are such that such a transition zone of the recording stratum's relative phase shift versus thickness variation curve continues to be proximate said nominal thickness as the absorption of said recording layer to said given wavelength decreases.

Claim 5

The invention defined in claim 1 wherein the real refractive index of said recording layer at said given wavelength is greater than about 1.4.

Claim 6

The invention defined in claim 1 wherein the imaginary refractive index of said recording layer is in the range of from about 0.3 to about 0.8.

Claim 7

The invention defined in claim 1 wherein the real refractive index of said recording layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said recording layer is in the range of from about 0.3 to about 0.8.

Claim 8

A record element adapted for improved real-time writing and reading of high density information with light of a given wavelength, said element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface; (a) said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a second reflectance maximum of magnitude substantially larger than that of its first reflectance minimum; and (b) said stratum having a nominal thickness generally proximate the thickness corresponding to said second reflectance maximum.

Claim 9

A record element adapted for improved real-time writing and reading of high density information with light of a given wavelength, said element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface; (a) said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a second reflectance maximum of magnitude substantially larger than that of its first reflectance minimum; and (b) said stratum having a nominal thickness generally proximate the thickness corresponding to said second reflectance maximum.

Claim 10

The invention defined in claim 7 wherein said nominal thickness is proximate a transition, from a zone of gradual slope to a zone of rapid slope, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby decreases in thickness of said recording stratum during deformation recording will yield substantial differences in relative phase shift between reading light of said given wavelength reflected from recorded and non-recorded portions of said record element.

Claim 11

The invention defined in claim 8 wherein the optical constants of said recording layer are such that such a transition zone of the recording stratum's relative phase shift versus thickness variation curve continues to be proximate said nominal thickness as the absorption of said recording layer to said given wavelength decreases.

Claim 12

The invention defined in claim 7 wherein the real refractive index of said recording layer at said given wavelength is greater than about 1.4.

Claim 13

The invention defined in claim 7 wherein the imaginary refractive index of said recording layer is in the range of from about 0.3 to about 0.8.

Claim 14

The invention defined in claim 7 wherein the real refractive index of said recording layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said recording layer is in the range of from about 0.3 to about 0.8.

Claim 15

In a record element of the type comprising a support having a smooth reflective surface and a recording stratum, including a heat-deformable, dye-binder layer, overlying said reflective surface, said element containing information in the form of a plurality of discrete, high density pits formed by thermal deformation of said dye-binder layer by a beam of light of a given wavelength to which said dye is strongly absorptive, the improvement wherein: (a) said dye-binder layer has optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a first reflectance minimum having a high depth of modulation; (b) said stratum has a nominal thickness sufficiently greater than the thickness corresponding to said first reflection minimum to effect reflection of a significant minor porportion of light of said given wavelengths; and (c) said pits are recorded to a depth such that, upon reading of said record element with a beam of radiation of said given wavelength, the magnitude of such radiation reflected from pitted and non-pitted portions of said element is approximately equal.

Claim 16

In a record element of the type comprising a support having a smooth reflective surface and a recording stratum, including a heat-deformable, dye-binder layer, overlying said reflective surface, said element containing information in the form of a plurality of discrete, high density pits formed by thermal deformation of said dye-binder layer by a beam of light of a given wavelength to which said dye is strongly absorptive, the improvement wherein: (a) said dye-binder layer has optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a first reflectance minimum having a high depth of modulation; (b) said stratum has a nominal thickness sufficiently greater than the thickness corresponding to said first reflection minimum to effect reflection of a significant minor porportion of light of said given wavelengths; and (c) said pits are recorded to a depth such that, upon reading of said record element with a beam of radiation of said given wavelength, the magnitude of such radiation reflected from pitted and non-pitted portions of said element is approximately equal.

Claim 17

The invention defined in claim 13 wherein said nominal thickness is proximate a transition, from a zone of gradual change to a zone of rapid change, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby the decreased thickness of said recording stratum in pitted regions yield substantial relative phase changes to light of said given wavelength reflected from said record element.

Claim 18

The invention defined in claim 13 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4.

Claim 19

The invention defined in claim 13 wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 20

The invention defined in claim 13 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4 and wherein the imaginary reflective index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 21

In a record element of the type comprising a support having a smooth reflective surface and a recording stratum, including a heat-deformable, dye-binder layer, overlying said reflective surface, said element containing information in the form of a plurality of discrete, high density pits formed by thermal deformation of said dye-binder layer by a beam of light of a given wavelength to which said dye is strongly absorptive, the improvement wherein: (a) said dye-binder layer has optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a second reflectance maximum of magnitude substantially larger than that of the first reflectance minimum; (b) said stratum has a nominal thickness generally proximate the thickness corresponding to said second reflectance maximum; and (c) said pits are recorded to a depth such that, upon reading of said record element with a beam of radiation of said given wavelength, the magnitude of such radiation reflected from pitted and non-pitted portions of said element is approximately equal.

Claim 22

In a record element of the type comprising a support having a smooth reflective surface and a recording stratum, including a heat-deformable, dye-binder layer, overlying said reflective surface, said element containing information in the form of a plurality of discrete, high density pits formed by thermal deformation of said dye-binder layer by a beam of light of a given wavelength to which said dye is strongly absorptive, the improvement wherein: (a) said dye-binder layer has optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a second reflectance maximum of magnitude substantially larger than that of the first reflectance minimum; (b) said stratum has a nominal thickness generally proximate the thickness corresponding to said second reflectance maximum; and (c) said pits are recorded to a depth such that, upon reading of said record element with a beam of radiation of said given wavelength, the magnitude of such radiation reflected from pitted and non-pitted portions of said element is approximately equal.

Claim 23

The invention defined in claim 18 wherein said nominal thickness is proximate a transition, from a zone of gradual change to a zone of rapid change, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby reading light of said given wavelength reflected from pitted and non-pitted regions of said record element differ substantially in phase.

Claim 24

The invention defined in claim 18 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4 .

Claim 25

The invention defined in claim 18 wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 26

The invention defined in claim 18 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 29

The invention defined in claim 23 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4.

Claim 30

The invention defined in claim 23 wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 31

The invention defined in claim 23 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 32

The invention defined in claim 23 wherein said nominal thickness is proximate a transition, from a zone of gradual change to a zone of rapid change, in the relative phase shift versus thickness variation curve of said recording stratum with respect to said given wavelength, whereby decreases in thickness of said recording stratum during deformation recording will yield substantial relative phase changes in said reading portions reflected from pitted and non-pitted regions of said record element.

Claim 35

The invention defined in claim 28 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4.

Claim 36

The invention defined in claim 28 wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 37

The invention defined in claim 28 wherein the real refractive index of said dye-binder layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said dye-binder layer is in the range of from about 0.3 to about 0.8.

Claim 38

The invention defined in claim 28 wherein said nominal thickness is proximate a transition, from a zone of gradual change to a zone of rapid change, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby reading light of said given wavelength reflected from pitted and non-pitted regions of said record element is substantially different in phase.

Claim 39

Apparatus for real-time optical writing and reading of high density information with light of a given wavelength, said apparatus comprising: (a) a record element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface, said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a first reflectance minimum having a high depth of modulation and said stratum having a nominal thickness sufficiently greater than the thickness corresponding to said first reflectance minimum to effect reflection of a significant minor proportion of light of said given wavelength; (b) means for scanning said record element with a laser beam of said given wavelength; (c) control means for: (1) in a writing mode, controlling the intensity of said laser beam so as to thermally form a plurality of discrete pits of generally predetermined depth in said layer in a pattern representing such information, said predetermined pit depth being such that, upon reading of said record element with said laser beam, the magnitude of such light reflected from pitted and non-pitted portions of said element is approximately equal; and (2) in a reading mode, controlling said radiation beam so as to provide a uniform illumination of recorded pits of slightly less intensity than will melt said layer; and (d) means for sensing the reading radiation reflected from said record element with a far field detector adapted to detect and produce output signals primarily in response to differences in the phase of the read light beam reflected from pitted and non-pitted portions of said record element.

Claim 40

Apparatus for real-time optical writing and reading of high density information with light of a given wavelength, said apparatus comprising: (a) a record element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface, said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a first reflectance minimum having a high depth of modulation and said stratum having a nominal thickness sufficiently greater than the thickness corresponding to said first reflectance minimum to effect reflection of a significant minor proportion of light of said given wavelength; (b) means for scanning said record element with a laser beam of said given wavelength; (c) control means for: (1) in a writing mode, controlling the intensity of said laser beam so as to thermally form a plurality of discrete pits of generally predetermined depth in said layer in a pattern representing such information, said predetermined pit depth being such that, upon reading of said record element with said laser beam, the magnitude of such light reflected from pitted and non-pitted portions of said element is approximately equal; and (2) in a reading mode, controlling said radiation beam so as to provide a uniform illumination of recorded pits of slightly less intensity than will melt said layer; and (d) means for sensing the reading radiation reflected from said record element with a far field detector adapted to detect and produce output signals primarily in response to differences in the phase of the read light beam reflected from pitted and non-pitted portions of said record element.

Claim 41

The invention defined in claim 33 wherein the real refractive index of said layer at said given wavelength is greater than about 1.4.

Claim 42

The invention defined in claim 33 wherein the imaginary refractive index of said layer is in the range of from about 0.3 to about 0.8.

Claim 43

The invention defined in claim 33 wherein the real refractive index of said layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said layer is in the range of from about 0.3 to about 0.8.

Claim 44

The invention defined in claim 33 wherein said nominal thickness is proximate a transition, from a zone of gradual change to a zone of rapid change, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby decreases in thickness of said recording stratum incident to pit formation yield a substantial change in relative phase of reflected reading light.

Claim 45

Apparatus for real-time, optical writing and reading of high density information with a laser beam of a given wavelength, said apparatus comprising: (a) a record element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface, said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a second reflectance maximum of magnitude substantially larger than that of the first reflectance minimum and said stratum having a nominal thickness generally proximate the thickness corresponding to said second reflectance maximum; (b) means for scanning said record element with a laser beam of said given wavelength; (c) control means for: (1) in a writing mode, controlling the intensity of said laser beam so as to thermally deform a plurality of discrete pits of generally predetermined depth in said layer in a pattern representing such information, said predetermined pit depth being such that, upon reading of said record element with said laser beam, the magnitude of such light reflected from pitted and non-pitted portions of said element is approximately equal; and (2) in a reading mode, controlling said radiation beam so as to provide a uniform illumination of recorded pits of slightly less intensity than will melt said dye-binder layer; and (d) means for sensing the reading radiation reflected rom said record element with a far field detector adapted to produce output signals primarily in response to differences in phase of light reflected from pitted and non-pitted portions of said element.

Claim 46

Apparatus for real-time, optical writing and reading of high density information with a laser beam of a given wavelength, said apparatus comprising: (a) a record element comprising a support having a smooth reflective surface and a recording stratum including a heat-deformable, dye-binder layer overlying said reflective surface, said dye-binder layer having optical constants such that the reflectance versus thickness variation curve of said stratum, with respect to said given wavelength, exhibits a second reflectance maximum of magnitude substantially larger than that of the first reflectance minimum and said stratum having a nominal thickness generally proximate the thickness corresponding to said second reflectance maximum; (b) means for scanning said record element with a laser beam of said given wavelength; (c) control means for: (1) in a writing mode, controlling the intensity of said laser beam so as to thermally deform a plurality of discrete pits of generally predetermined depth in said layer in a pattern representing such information, said predetermined pit depth being such that, upon reading of said record element with said laser beam, the magnitude of such light reflected from pitted and non-pitted portions of said element is approximately equal; and (2) in a reading mode, controlling said radiation beam so as to provide a uniform illumination of recorded pits of slightly less intensity than will melt said dye-binder layer; and (d) means for sensing the reading radiation reflected rom said record element with a far field detector adapted to produce output signals primarily in response to differences in phase of light reflected from pitted and non-pitted portions of said element.

Claim 47

The invention defined in claim 38 wherein the real refractive index of said layer at said given wavelength is greater than about 1.4.

Claim 48

The invention defined in claim 38 wherein the imaginary refractive index of said layer is in the range of from about 0.3 to about 0.8.

Claim 49

The invention defined in claim 38 wherein the real refractive index of said layer at said given wavelength is greater than about 1.4 and wherein the imaginary refractive index of said layer is in the range of from about 0.3 to about 0.8.

Claim 50

The invention defined in claim 38 wherein said nominal thickness is proximate a transition, from a zone of gradual change to a zone of rapid change, in the relative phase shift versus thickness variation curve of said recording stratum with respect to light of said given wavelength, whereby reading light of said given wavelength reflected from pitted and non-pitted regions of said record element differs substantially in phase.