Recording and reading method and device for dye based write-once DVD medium

A recording and reading method of recording information in a dye-based write-once digital versatile disc (DVD) comprising a substrate having a wobbled guide groove and a recording layer located overlying the substrate and comprising an organic dye, comprising:

• first irradiating the DVD with three kinds of single light pulses, each of which comprising a recording area to record a mark and a cooling area having a light quantity not greater than 0.1 mW for a predetermined time while a space is formed between the adjacent marks;
• and
• second irradiating the mark with light to reproduce information recorded in the DVD,
• wherein, when the mark having a shortest length is formed, the first irradiating comprises:
• irradiating the DVD with a first single light pulse in which an entire of the recording area has a power level of W0 or a front end portion of the recording area has a power level of W0 and a rest portion of the pulse has a power level of W1;
• when the mark having a second shortest length is formed, the irradiating comprises:
• irradiating the DVD with a second single light pulse in which an entire of the recording area has a power level of W1;
• at least a front end portion of the recording area has a power level of W0 and a rest portion thereof has a power level of W1;
• or at least a front end portion of the recording area has a power level of W1 and a rest portion thereof has a power level of W2;
• when the mark having a third shortest length or longer is formed, the irradiating comprises:
• irradiating the DVD with a third single light pulse in which at least a rear end portion of the recording area has a power level of W0 and a rest portion thereof has a power level of W1;
• or at least a rear end portion of the recording area has a power level of W1 and a rest portion thereof has a power level of W2;
• wherein W0, W1 and W2 satisfy a relationship, W0>W1>W2, and wherein the highest power level of the second single light pulse is not lower than the highest power level of the third light pulse.

A recording and reading device comprising:

• a motor driver;
• a spindle motor;
• and
• an optical pickup configured to irradiate a dye-based write-once digital versatile disc (DVD) comprising a substrate having a wobbled guide groove and a recording layer located overlying the substrate and comprising an organic dye, with three kinds of single light pulses, each of which comprising a recording area to record a mark and a cooling area having a light quantity not greater than 0.1 mW for a predetermined time while a space is formed between the adjacent marks, and second irradiating the mark with light to reproduce information recorded in the DVD,
• wherein, when the mark having a shortest length is formed, the first irradiating comprises:
• irradiating the DVD with a first single light pulse in which an entire of the recording area has a power level of W0 or a front end portion of the recording area has a power level of W0 and a rest portion of the pulse has a power level of W1;
• when the mark having a second shortest length is formed, the irradiating comprises:
• irradiating the DVD with a second single light pulse in which an entire of the recording area has a power level of W1;
• at least a front end portion of the recording area has a power level of W0 and a rest portion thereof has a power level of W1;
• or at least a front end portion of the recording area has a power level of W1 and a rest portion thereof has a power level of W2;
• when the mark having a third shortest length or longer is formed, the irradiating comprises:
• irradiating the DVD with a third single light pulse in which at least a rear end portion of the recording area has a power level of W0 and a rest portion thereof has a power level of W1;
• or at least a rear end portion of the recording area has a power level of W1 and a rest portion thereof has a power level of W2;
• wherein W0, W1 and W2 satisfy a relationship, W0 >W1 >W2, and wherein the highest power level of the second single light pulse is not lower than the highest power level of the third light pulse.