US 5,109,373 A · Optical information recording method

Abstract

A recording apparatus overwrites an input signal having pulse duration periods and pulse spacing periods to an optical disk by irradiation of a laser beam to form recording marks corresponding to the pulse duration periods. The apparatus includes a detector for detecting a leading edge of the pulse duration period and for producing a start signal thereupon, another detector for detecting a trailing edge of the pulse duration period and for producing a stop signal thereupon, a pattern setting circuit for setting a predetermined basic pattern, and a pattern generator for generating the basic pattern from its beginning in response to the start signal and for terminating the generation of the basic pattern in response to the stop signal. The apparatus further includes a circuit for forming a modulated signal using a full or portion of the basic pattern produced from the pattern generator. The laser output is produced in according with the modulated signals.

Claims33

Dependent claims

A recording method which overwrites an input signal having pulse duration periods and pulse spacing periods to a recording medium by irradiation of an optical beam by a beam emitter to form recording marks corresponding to said pulse duration periods, which method comprising the steps of:

converting said pulse duration period of said input signal to a modulation pattern of pulse string such that:
(I) the pulse width of a second pulse of said pulse string is made greater than the pulse width of each pulse in successive pulses succeeding thereto and is made constant irrespective of the length of the recording mark;
(II) the pulse width in said successive pulses is maintained constant;
(III) the pulse cycle period in said successive pulses is maintained constant;
and
(IV) when forming a recording mark of Mth shortest entry, the number of narrow pulses in the modulation pattern is {Ma+b} pulses, wherein a and b are constants, a being a positive integer and b being an integer equal to or greater than -a;
applying a first predetermined power level during the presence of pulse in said modulation pattern and applying a second predetermined power level during the absence of pulse in said modulation pattern to form a modulated signal;
and
driving said beam emitter by said modulated signal.

6 more elements

converting said pulse duration period of said input signal to a modulation pattern of pulse string such that:
(I) the pulse width of at least one of the first and second pulses of said pulse string is made greater than the pulse width of each pulse in successive pulses succeeding thereto and is made constant irrespective of the length of the recording mark;
(II) the pulse width in said successive pulses is maintained constant;
(III) the pulse cycle period in said successive pulses is maintained constant, such that said successive pulses have a repeat cycle period .tau. given as follows:
.tau..ltoreq..lambda./L
in which .lambda. is the wavelength of the light source used for recording, and L is the relative speed of a recording medium and said optical beam from beam emitter;
and
(IV) when forming a recording mark of Mth shortest entry, the number of narrow pulses in the modulation pattern is {Ma+b} pulses, wherein a and b are constants, a being a positive integer and b being an integer equal to or greater than -a;
applying a first predetermined power level during the presence of pulse in said modulation pattern and applying a second predetermined power level during the absence of pulse in said modulation pattern to form a modulated signal;
and
driving said beam emitter by said modulated signal.

8 more elements

Dependencies are inferred from the claim text.

Optical information recording method

Life of this patent

Optical information recording method

Life of this patent

Abstract

Claims33