Optical information recording method

A method of recording an information signal by using a single light beam on a recording medium which is changeable between two states which are optically distinguishable from each other, characterized by applying the single light beam in response to the information signal to the recording medium for a predetermined duration while changing the single light beam so as to have a higher energy at a beginning portion of the predetermined duration than an energy at an ending portion of the predetermined duration thereby causing the recording medium to melt uniformly at an area applied with the single light beam and causing a state change from one of the two states to the other to form a record mark having substantially a symmetrical shape;

• wherein the single light beam applied for the predetermined duration consists of a train of a plurality of light pulses whose pulse widths reduce gradually from the beginning to the ending of the predetermined duration.

A method of recording an information signal by using a single light beam on a recording medium which is changeable between two states which are optically distinguishable from each other, characterized by applying the single light beam in response to the information signal to the recording medium for a predetermined duration while changing the single light beam so as to have a higher energy at a beginning portion of the predetermined duration than an energy at an ending portion of the predetermined duration thereby causing the recording medium to melt uniformly at an area applied with the single light beam and causing a state change from one of the two states to the other to form a record mark having substantially a symmetrical shape;

• wherein the single light beam applied for the predetermined duration consists of a train of a plurality of light pulses whose pulse intervals increase gradually from the beginning to the ending of the predetermined duration.

A method of recording an information signal by using a single light beam on a recording medium which is changeable between two states which are optically distinguishable from each other, characterized by applying the single light beam in response to the information signal to the recording medium for a predetermined duration while changing the single light beam so as to have a higher energy at a beginning portion of the predetermined duration than an energy at an ending portion of the predetermined duration thereby causing the recording medium to melt uniformly at an area applied with the light beam and causing a state change from one of the two states to the other to form a record mark having substantially a symmetrical shape;

• wherein the single light beam applied for the predetermined duration consists of a train of a plurality of light pulses whose peak power levels decrease gradually from the beginning to the ending of the predetermined duration.

A method of recording an information signal by using a single light beam on a recording medium which is changeable between first and second states which are optically distinguishable from each other, comprising the steps of:

• applying the single light beam, as a recording light pulse, in response to the information signal to the recording medium for a predetermined duration while modifying the single light beam into a train of auxiliary light pulses each having a shorter duration than the predetermined duration to cause the recording medium to melt and become the first state thereby forming a record mark having a substantially symmetric shape, a first occurring auxiliary light pulse in the train of the auxiliary light pulses having a longest duration among durations of the auxiliary light pulses in the train of the auxiliary light pulses;
• and
• applying the single light beam to an area of the recording medium before and after the single record mark while keeping the light beam a predetermined constant power level to cause the area to heat and become a state substantially identical to the second state.

A method of recording an information signal by using a single light beam on a recording medium which is reversibly changeable between two states which are optically distinguishable from each other, characterized by applying the light beam, as a recording light pulse, in response to the information signal to the recording medium for a predetermined duration while modulating the recording light pulse to have a higher energy at a beginning portion of the predetermined duration than an energy at an ending portion of the predetermined duration thereby causing the recording medium to melt uniformly at an area applied with the recording light pulse and cause a state change from one of the two states to the other to form a record mark having substantially a symmetrical shape, wherein the recording light pulse applied for the predetermined duration consists of a train of a plurality of light pulses among which a first occurring light pulse has a wider pulse width than a pulse width of a last occurring light pulse.

A method of recording an information signal by using a single light beam on a recording medium which is reversibly changeable between two states which are optically distinguishable from each other, characterized by applying the single light beam, as a recording light pulse, in response to the information signal to the recording medium for a predetermined duration while modulating the recording light pulse to have a higher energy at a beginning portion of the predetermined duration than an energy at an ending portion of the predetermined duration thereby causing the recording medium to melt uniformly at an area applied with the recording light pulse and cause a state change from one of the two states to the other to form said area into a record mark having substantially a symmetrical shape, wherein the recording light pulse applied for the predetermined duration consists of a train of a plurality of light pulses occurring such that a first occurring pulse interval is shorter than a last occurring pulse interval in the predetermined duration.

A method of recording an information signal by using a single light beam on a recording medium which is reversibly changeable between two states which are optically distinguishable from each other, characterized by applying the single light beam, as a recording light pulse, in response to the information signal to the recording medium for a predetermined duration while modulating the recording light pulse to have a higher energy at a beginning portion of the predetermined duration than an energy at an ending portion of the predetermined duration thereby causing the recording medium to melt uniformly at an area applied with the recording light pulse and cause a state change from one of the two states to the other to form said area into a record mark having substantially a symmetrical shape, m wherein the recording light pulse applied for the predetermined duration consists of a train of a plurality of light pulses among which a first occurring light pulse has a higher peak power level than a peak power level of a last occurring light pulse.