REAL TIME POWER CONTROL FOR OPTICAL RECORDING DRIVES

• US 20090097368A1
• Filed: 03/05/2007
• Published: 04/16/2009
• Est. Priority Date: 03/13/2006
• Status: Active Grant

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips N.V.
• Inventors: Vlutters, Ruud, Yin, Bin
• Granted Patent: US 7,995,441 B2
• Time in Patent Office: Days
• US Class Current: 369/47.15
• CPC Class Codes: G11B 11/10595 Control of operating function
• CPC Class Codes: G11B 7/0062 Overwriting strategies, e.g. recording pulse sequences with erasing level used for phase-change media
• CPC Class Codes: G11B 7/1263 Power control during transducing, e.g. by monitoring

Abstract

The invention discloses an optical recording drive for recording data on an optical carrier such as an optical disk of the DVD or BD format. A radiation source is arranged to emit a write pulse train (80) for writing an optically detectable effect (90) i.e. a pit or mark. Photo detection means (10) detects a first reflected radiation beam pulse (R1) from a start time portion of the write pulse train (80) and generates a corresponding first signal (PS1) indicative of the power in the first pulse, the photo detection means (10) further detects a second reflected radiation pulse (R2) from an end time portion of the write pulse train (80) and generates a corresponding second signal (PS2) indicative of the power in the second pulse. By comparing (e.g. the heights of) the first signal (PS1) and the second signal (PS2), it is possible to get an indication of the received power in the optically detectable effect (90) as delivered by a power level (81; 82) in the write pulse train (80) continuously during writing and for a broad range of carrier rotation speeds.

Claims

1. An optical recording drive adapted for recording data on an associated optical carrier (1), the optical recording drive comprising:

a radiation source (4) capable of emitting a radiation beam (5), said beam being adapted to write information on the optical carrier (1) as optically detectable effects (90),

a write strategy generator (26) capable of providing the radiation source (4) with a write strategy for an optically detectable effect (90), the radiation source being arranged to emit a corresponding write pulse train (80) for writing the optically detectable effect (90), said write pulse train comprising at least an upper (81) and a lower (82) level of power,

photo detection means (10) arranged to detect reflected radiation (8) from the optical carrier (1), said photo detection means being capable of detecting a first reflected radiation beam pulse (R1) from a start time portion of the write pulse train (80) and generating a corresponding first signal (PS1) indicative of the power in the first pulse,

the photo detection means (10) further being capable of detecting a second reflected radiation pulse (R2) from an end time portion of the write pulse train (80) and generating a corresponding second signal (PS2) indicative of the power in the second pulse, and

processing means (50) for comparing said first signal (PS1) and said second signal (PS2) so as to obtain an indication of the received power in the optically detectable effect (90) as delivered by a power level (81;

82) in the write pulse train (80).

2. An optical recording drive according to claim 1, wherein the processing means (50) is adapted to compare the first signal (PS1) and the second signal (PS2) by calculating a ratio between said first signal (PS1) and said second signal (PS2).

3. An optical recording drive according to claim 1, wherein the processing means (50) is adapted to compare the first signal (PS1) and the second signal (PS2) by calculating a difference between said first signal (PS1) and said second signal (PS2).

4. An optical recording drive according to claim 1, wherein the first and the second signal (PS1;

PS2) is a central aperture signal (CA) from the optical carrier (1).

5. An optical recording drive according to claim 4, wherein the optical drive is adapted to identify the first (PS1) and second (PS2) signal by analysis of the central aperture signal (CA) during writing.

6. An optical recording drive according to claim 4, wherein the optical drive is adapted to identify the first (PS1) and second (PS2) signal from data provided by write strategy generator (26) and/or from data to the write strategy generator (26).

7. An optical recording drive according to claim 1, wherein the processing means (50) is adapted to obtain an indication of the received power in the optically detectable effect (90) as delivered by a power level (81;

82) in the write pulse train (80) by utilizing the time difference of said first signal (PS1) and said second signal (PS2).

8. An optical recording drive according to claim 1, wherein the photo detection means (10) has a sampling frequency of said first and/or said second signal (PS1;

PS2) substantially larger than a clock frequency of the data to be recorded on the optical carrier (1).

9. An optical recording drive according to claim 1, wherein the upper power level (81) in the write pulse train (80) is adapted for erasing an optically detectable effect (90) on the optical carrier (1).

10. Processing means (50) for controlling the operation of an associated optical recording drive adapted for recording data on an optical carrier (1), the optical drive comprising:

a radiation source(4) capable of emitting a radiation beam (5), said beam being adapted to write information on the optical carrier (1) as optically detectable effects (90),

a write strategy generator (26) capable of providing the radiation source (4) with a write strategy for an optically detectable effect (90), the radiation source being arranged to emit a corresponding write pulse train (80) for writing the optically detectable effect (90), said write pulse train comprising at least an upper (81) and a lower (82) level of power,

photo detection means (10) arranged to detect reflected radiation (8) from the optical carrier (1), said photo detection means being capable of detecting a first reflected radiation pulse (R1) from a start time portion of the write pulse train (80) and generating a corresponding first signal (PS1) indicative of the power in the first pulse, and

the photo detection means (10) further being capable of detecting a second reflected radiation pulse (R2) from an end time portion of the write pulse train (80) and generating a corresponding second signal (PS2) indicative of the power in the second pulse,

wherein the processing means (50) is adapted to compare said first signal (PS1) and said second signal (PS2) so as to obtain an indication of the received power in the optically detectable effect (90) as delivered by a power level (81;

82) in the write pulse train (80).

11. A method for operating an optical recording drive adapted for recording data on an optical carrier (1), the method comprising the steps of:

emitting a radiation beam (5) by a radiation source(4), said beam being adapted to write information on the optical carrier (1) as optically detectable effects (90),

providing the radiation source (4) with a write strategy from a write strategy generator (26) for writing an optically detectable effect (90), the radiation source being arranged to emit a corresponding write pulse train (80) for writing the optically detectable effect (90), said write pulse train comprising at least an upper (81) and a lower (82) level of power,

detecting reflected radiation (8) from the optical carrier (1) by photo detection means (10), said photo detection means being capable of detecting a first reflected radiation pulse (R1) from a start time portion of the write pulse train (80) and generating a corresponding first signal (PS1) indicative of the power in the first pulse,

detecting a second reflected radiation pulse (R2) by the photo detection means (10) from an end time portion of the write pulse train (80) and generating a corresponding second signal (PS2) indicative of the power in the second pulse, and

comparing said first signal (PS1) and said second signal (PS2) by processing means (50) so as to obtain an indication of the received power in the optically detectable effect (90) as delivered by a power level (81;

82) in the write pulse train (80).

12. A computer program product being adapted to enable a computer system comprising at least one computer having data storage means associated therewith to control an optical recording drive according to the method as claimed in claim 11.

13. An optical recording carrier (1) for recording information by irradiating the optical recording carrier by means of a radiation beam (5), the recording carrier comprising an area containing control information indicative of a recording process whereby information can be recorded on said recording carrier, the control information comprising values of recording parameters for the recording process, wherein the control information comprises information related to the comparison of the first (PS1) and second signal (PS2) in the method as claimed in claim 11.