Light spot advancing direction judging device and method, optical head device control device and method, and optical disk recording/reproducing device

A light spot moving direction judging method for detecting reflected light coming from a main spot formed on an optical disc by a first light beam irradiated onto the optical disc and reflected light coming from a side spot formed on the optical disc by a second light beam also irradiated onto the optical disc and judging a radial moving direction of the main spot based on an outcome of the detection, said optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, the method comprising:

• a first computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from the main spot by means of first two divided detecting regions;
• a second computing step of computationally producing a difference signal of the two signals obtained by detecting a quantity of the reflected light coming from the one side spot by means of second two divided detecting regions;
• a first binarizing step of binarizing the difference signal of the main spot computationally produced from the first computing step;
• a second binarizing step of binarizing the difference signal of the side spot computationally produced from the second computing step;
• and
• a judging step of judging moving direction of the main spot based on the binarized data from the first binarizing step and the binarized data from the second binarizing step by using two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flip circuits and an inverted output of an other flip-flip circuit according to a low or high state of the binarized data from said first binarizing step.

A light spot moving direction judging device for detecting reflected light coming from a main spot formed on an optical disc by a first light beam irradiated onto the optical disc and reflected light coming from a pair of second side spots formed on the optical disc by a pair of light beams also irradiated onto the optical disc and judging a radial moving direction of the main spot based on an the outcome of the detection, said optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, the device comprising:

• first computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from the main spot by means of first two divided detecting regions;
• second computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from one of the pair of side spots by means of second two divided detecting regions;
• third computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from the other of the pair of side spots by means of third two divided detecting regions;
• fourth computing means for computationally producing a difference signal of the difference signal computationally produced by the second computing means and the difference signal computationally produced by the third computing means;
• first binarizing means for binarizing the difference signal of the main spot computationally produced by the first computing means;
• second binarizing means for binarizing the difference signal of the difference signals of the two side spots computationally produced by the fourth computing means;
• and
• judging means for judging the radial moving direction of the main spot based on the binarized data from the first binarizing means and the binarized data from the second binarizing means, wherein said judging means comprises a judgment data generating section for generating judgment data for judging the radial moving direction of said main spot, said judgement data generating section including two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing means.

A light spot moving direction judging method for detecting reflected first light coming from a main spot formed on an optical disc by a light beam irradiated onto the optical disc and reflected light coming from a pair of side spots formed on the optical disc by a pair of second light beams also irradiated onto the optical disc and judging a radial moving direction of the main spot based on an outcome of the detection, said optical disc having lands and grooves helically arranged side by side on the surface and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, the method comprising:

• a first computing step of computationally producing a difference signal of the two signals obtained by detecting a quantity of the reflected light coming from the main spot by means of two divided detecting regions;
• a second computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from one of the pair of side spots by means of second two divided detecting regions;
• a third computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from the other of the pair of side spots by means of third two divided detecting regions;
• a fourth computing step of computationally producing difference signal of the difference signal computationally produced from the second computing step and the difference signal computationally produced from the third computing step;
• a first binarizing step of binarizing the difference signal of the main spot computationally produced from the first computing step;
• a second binarizing step of binarizing the difference signal of the difference signals of the two side spots computationally produced from the fourth computing step;
• and
• a judging step of judging the radial moving direction of the main spot based on the binarized data from the first binarizing step and the binarized data from the second binarizing step by using two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing step.

An optical head control device for controlling an optical head adapted to irradiate a main light beam and a pair of side light beams onto an optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, said device comprising:

• light spot moving direction judging device having:
• a first computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from a main spot by means of first two divided detecting regions;
• second computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from one of a pair of side spots by means of second two divided detecting regions;
• first binarizing means for binarizing the difference signal of the main spot computationally produced by the first computing means;
• second binarizing means for binarizing the difference signal of the one side spot computationally produced by the second computing means;
• and
• judging means for judging a moving direction of the main spot based on the binarized data from the first binarizing means and the binarized data from the second binarizing means;
• and
• control means for controlling a position of the optical head in a radial direction of the optical disc based on the moving direction of the main spot as judged by the light spot moving direction judging device, said optical head irradiating light beams onto the optical disc, wherein said judging means comprises a judgment data generating section for generating judgment data for judging the radial moving direction of said main spot, said judgment data generating section including two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing means.

An optical head control method for controlling an optical head that forms a main spot and a pair of side spots onto an optical disc having lands and grooves helically arranged side by side on a surface thereof that operate as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, said method comprising:

• a light spot moving direction judging step including:
• a first computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from the main spot by means of first two divided detecting regions;
• a second computing step of computationally producing difference signal of two signals obtained by detecting a quantity of the reflected light coming from the one side spot by means of second two divided detecting regions;
• a first binarizing step of binarizing the difference signal of the main spot computationally produced from the first computing step;
• a second binarizing step of binarizing the difference signal of the side spot computationally produced from the second computing step;
• and
• a judging step of judging a moving direction of the main spot based on binarized data from the first binarizing step and binarized data from the second binarizing step;
• and
• a control step of controlling position of the optical head in a radial direction of the optical disc based on the moving direction of the main spot as judged in the light spot moving direction judging step by using two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and a inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing step.

An optical head control device for controlling an optical head adapted to form a main spot and a pair of side spots onto an optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, said device comprising:

• a light spot moving direction judging device having:
• first computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from the main spot by means of first two divided detecting regions;
• second computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from one of the side spots by means of second two divided detecting regions;
• third computing means for computationally producing a difference signal of the two signals obtained by detecting a quantity of the reflected light coming from other side spots by means of third two divided detecting regions;
• fourth computing means for computationally producing a difference signal of the difference signal computationally produced by the second computing means and the difference signal computationally produced by the third computing means;
• first binarizing means for binarizing the difference signal of the main spot computationally produced by the first computing means;
• second binarizing means for binarizing the difference signal of the difference signal computationally produced by the fourth computing means;
• and
• judging means for judging a moving direction of the main spot based on binarized data from the first binarizing means and binarized data from the second binarizing means;
• and
• control means for controlling a position of the optical head in a radial direction of the optical disc based on the moving direction of the main spot as judged by the light spot moving direction judging device, wherein said judging means comprises a judgment data generating section for generating judgment data for judging the radial moving direction of said main spot, said judgment data generating section including two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing means.

An optical head control method for controlling an optical head adapted to form a main spot and a pair of side spots onto an optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, said method comprising:

• a light spot moving direction judging step including:
• a first computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from the main spot by means of first two divided detecting regions;
• a second computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from one of the side spots by means of second two divided detecting regions;
• a third computing step of computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from an other of the side spots by means of third two divided detecting regions;
• a fourth computing step of computationally producing a difference signal of the difference signal computationally produced from the second computing step and the difference signal computationally produced from the third computing step;
• a first binarizing step of binarizing the difference signal of the main spot computationally produced from the first computing step;
• a second binarizing step of binarizing the difference signal of the difference signals of the two side spots computationally produced from the fourth computing step;
• and
• a judging step of judging a moving direction of the main spot based on binarized data from first binarizing step and the binarized data from the second binarizing step by using two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing step;
• and
• a control step of controlling a position of the optical head in a radial direction of the optical disc based on the moving direction of the main spot as judged in the light spot moving direction judging step.

An optical disc recording/replay apparatus for recording data on and reproducing data from an optical disc by forming a main spot of a light beam and a pair of side spots of light beams on an optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, said device comprising:

• a light spot moving direction judging device having:
• first computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from the main spot by means of first two divided detecting regions;
• second computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from one side spot by means of second two divided detecting regions;
• first binarizing means for binarizing the difference signal of the main spot computationally produced by the first computing means;
• second binarizing means for binarizing the difference signal of the one side spot computationally produced by the second computing means;
• and
• judging means for judging moving direction of the main spot based on binarized data from the first binarizing means and binarized data from the second binarizing means;
• and
• control means for controlling a position of the optical head in a radial direction of the optical disc based on the moving direction of the main spot as judged by the light spot moving direction judging device, wherein said judging means comprises a judgment data generating section for generating judgment data for judging the radial moving direction of said main spot, said judgment data generating section including two synchronous type flip-flop circuit and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing means.

An optical disc recording/replay apparatus for recording data on and reproducing data from an optical disc by forming a main spot of a light beam and a pair of side spots of light beams on an optical disc having lands and grooves helically arranged side by side on a surface thereof and operating as recording tracks, each pair of said lands located adjacently and sandwiching a groove and/or each pair of said grooves located adjacently and sandwiching a land respectively having different heights and/or depths, said device comprising:

• a light spot moving direction judging device having:
• first computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of reflected light coming from the main spot by means of first two divided detecting regions;
• second computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from one of the side spots by means of second two divided detecting regions;
• third computing means for computationally producing a difference signal of two signals obtained by detecting a quantity of the reflected light coming from an other of the side spots by means of third two divided detecting regions;
• fourth computing means for computationally producing a difference signal of the difference signal computationally produced by the second computing means and the difference signal computationally produced by the third computing means;
• first binarizing means for binarizing the difference signal of the main spot computationally produced by the first computing means;
• second binarizing means for binarizing the difference signal produced by the fourth computing means;
• and
• judging means for judging a moving direction of the main spot based on binarized data from first binarizing means and the binarized data from the second binarizing means;
• and
• control means for controlling a position of the optical head in a radial direction of the optical disc based on the moving direction of the main spot as judged by the light spot moving direction judging device, wherein said judging means comprises a judgment data generating section for generating judgment data for judging the radial moving direction of said main spot, said judgment data generating section including two synchronous type flip-flop circuits and a changeover switch for selectively outputting a positive output of one of the flip-flop circuits and an inverted output of an other flip-flop circuit according to a low or high state of the binarized data from said first binarizing means.