Focal offset recording system and method
AssigneeHewlett-Packard Development Company, L.P.
InventorCharles R. Weirauch
Life of this patent
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Abstract
The present invention is embodied in a recording device and media for storing computer readable data on a removable storage medium that includes using a first wavelength to write data to the removable storage medium and creating marks while writing the data that have predetermined wide spot sizes so that the marks can be read with a second wavelength, different from the first wavelength, of another computer readable storage device.
Claims26
A method for storing computer readable data on a removable storage medium, comprising:
- using a first wavelength to write data to the removable storage medium;
- and
- creating marks while writing the data, wherein the marks have predetermined wide spot sizes to allow the marks to be read with a second wavelength, different from the first wavelength, of another computer readable storage device;
- wherein the medium provides a push-pull signal amplitude greater than 20% of the average amplitude of signal detected for the first wavelength reflected from the medium;
- and provides a push-pull signal amplitude less than 15% of the average amplitude of signal detected for the second wavelength reflected from the medium.
A recording device for storing computer readable data on a removable with storage medium, comprising:
- laser optics with a first wavelength for creating a spot size configured to generate marks and spaces in the removable storage medium;
- and
- a defocusing device configured to enlarge the spot size to within an optimal focal offset range, wherein the marks and spaces are capable of being read by disc reading devices that use laser optics with a second wavelength, which is different from the first wavelength;
- and
- a detector and circuitry configured to generate a push-pull signal amplitude greater than 20% of the average amplitude of signal detected by the detector as the first wavelength reflected from the medium;
- wherein the medium is configured to provide a push-pull signal amplitude less than 15% of the average amplitude of signal detected for the second wavelength reflected from the medium.
A recordable device for storing computer readable data on a removable storage medium, comprising:
- an objective lens;
- a laser diode coupled to the objective lens and operating at a first wavelength, wherein the laser diode is configured to create marks on the removable storage medium;
- a detector coupled to the laser diode and capable of distinguishing different foci;
- and
- an offset processor configured to determine a desired focal offset, wherein the marks created by the laser diode are capable of being read by disc reading devices that use laser optics with a second wavelength, which is different from the first wavelength;
- wherein the detector generates a push-pull signal amplitude greater than 20% of the average amplitude of signal detected by the detector as the first wavelength reflected from the medium;
- wherein the medium is configured to provide a push-pull signal amplitude less than 15% of the average amplitude of signal detected for the second wavelength reflected from the medium.
A removable recordable optical media for storing computer readable data, comprising:
- a disc shaped structure;
- and
- a spiral groove structure over at least part of the radius of the disc shaped structure;
- wherein the groove structure having a groove depth that will cause a strong push-pull signal from a first wavelength and a weak push-pull signal from a second wavelength;
- and
- wherein the strong push-pull signal amplitude is greater than 20% of the average amplitude of signal detected as light reflected from the groove structure and the weak push-pull signal is less than 15% of the average amplitude of signal detected as light reflected from the groove structure.
Dependencies are inferred from the claim text.