Advanced high density data write strategy
View Patent ↗A method of writing a mark to an optical disc includes receiving data to be written and generating a control signal for a laser pulse having a melt period that transitions to a growth period wherein the melt period is characterized by a melt power and the growth period is characterized by a growth power.
1. A method of writing a mark to an optical disc comprising:
receiving data to be written;
generating a control parameter having a value within a range from about zero to about one; and
generating a control signal for a laser pulse having a predefined period comprising a delay period, a melt period and a growth period, wherein the delay period begins with a transition from a read power to a premelt power, the melt period comprises a transition from the premelt power to a melt power configured to melt a region of the optical disc, the growth period begins with a transition from the melt power to a growth power configured to allow formation of crystalline material, includes a transition from the growth power to the read power and ends with an end of the predefined period, and wherein the premelt power, a a position of the transition from the premelt power to the melt power and a position of the transition from the growth power to the read power are adjusted based upon the data to be written and control parameter, wherein a duty cycle of the melt period and a duty cycle of the growth period are adjusted with respect to each other according to said control parameter.
2. A method of writing a mark to an optical disc as recited in claim 1 , wherein the duration of the growth power causes the formation of crystalline material.
3. A method of writing a mark to an optical disc as recited in claim 1 , wherein the premelt power is lower than the melt power.
4. A method of writing a mark to an optical disc as recited in claim 1 , wherein a position of the transition from the premelt power to the melt power within the melt period is varied based on the data to be written.
5. A method of writing a mark to an optical disc as recited in claim 1 , wherein a position of the transition from the premelt power to the melt power within the melt period is varied according to the mark being written.
6. A method of writing a mark to an optical disc as recited in claim 1 , wherein a position of the transition from the premelt power to the melt power is varied according to a previously written mark.
7. A method of writing a mark to an optical disc as recited in claim 1 , wherein a position of the transition between the melt power and the growth power is fixed within the predefined period of the laser pulse.
8. A method of writing a mark to an optical disc as recited in claim 1 , wherein the premelt power is varied according to the mark being written.
9. A method of writing a mark to an optical disc as recited in claim 1 , wherein the premelt power is varied according to a previously written mark.
10. A method of writing a mark to an optical disc as recited in claim 1 , wherein the position of the transition from the growth power to the read power is shifted in time with respect to the end of the predefined period of the laser pulse according to the mark being written.
11. A write strategy control signal generator comprising:
an input for receiving data to be written to an optical disc;
a processor configured to generate (i) a control parameter having a value within the range from about zero to about one and (ii) a control signal to control a laser pulse having a predefined period comprising a delay period, a melt period and a growth period, wherein the delay period begins with a transition from a read power to a premelt power, the melt period comprises a transition from the premelt power to a melt power configured to melt a region of the optical disc, the growth period begins with a transition from the melt power to a growth power configured to allow formation of crystalline material, includes a transition from the growth power to the read power and ends with an end of the predefined period, and wherein the premelt power, a position of the transition from the premelt power to the melt power and a position of the transition from the growth power to the read power are adjusted based upon the data to be written and control parameter, wherein a duty cycle of the melt period and a duty cycle of the growth period are adjusted with respect to each other according to said control parameter.
12. The method according to claim 1 , further comprising the step of:
controlling the premelt power and a time of the transition between the premelt power and the melt power to avoid interference with a previous mark.
13. The method according to claim 1 , further comprising the step of:
calibrating a duration of the delay period based on a signal read from said optical disc.
14. The method according to claim 1 , further comprising the step of:
calibrating the premelt power level based on a signal read from said optical disc.
15. The write strategy control signal generator according to claim 11 , wherein said processor is further configured to control said premelt power and a time of the transition from the premelt power to the melt power to avoid interference with a previous mark.
16. The write strategy control signal generator according to claim 11 , wherein said processor is further configured to calibrate the duration of said delay period based on a signal read from said optical disc.
17. The write strategy control signal generator according to claim 11 , wherein said processor is further configured to calibrate a level of said premelt power based on a signal read from said optical disc.
18. The write strategy control signal generator according to claim 11 , wherein said processor is further configured to adjust a level of the premelt power, the timing of the transition from the premelt power to the melt power and the timing of the transition ending the growth period based on a group of marks being written.
19. The write strategy control signal generator according to claim 11 , wherein said processor is further configured to select a premelt power level and a duration of said growth period based on media of said optical disc.
20. The write strategy control signal generator according to claim 11 , wherein said processor is further configured to determine a premelt power level and the duration of the melt power based on a signal read from said optical disc.
21. The method according to claim 1 , further comprising varying said value of said control parameter within said range according to a level of reflectivity to be obtained for said mark.