Optical disk device

An optical disk device reproducing information recorded on a signal recording surface of a plurality of layers of an optical disk, comprising:

• information reading means (60) for illuminating said optical disk (1) with a beam via an objective lens (42) and detecting light reflected from said optical disk (1) to read said information;
• acceleration means (55), when said information reading means (60) is focusing said beam on a signal recording surface of one of said plurality of layers, for generating and providing to said information reading means an acceleration signal for accelerating said objective lens (42) in a normal direction to a signal recording surface to focus said beam on a signal recording surface of another of said plurality of layers;
• and
• deceleration means (55) for generating and providing to said information reading means a deceleration signal for decelerating said objective lens when a predetermined period of time has elapsed since generation of said acceleration signal by said acceleration means.

An optical disk device reproducing information recorded on a signal recording surface of a plurality of layers of an optical disk, comprising:

• information reading means (60) for illuminating said optical disk (1) with a beam and detecting light reflected from said optical disk (1) to read said information;
• drive means (12, 13) for moving said information reading means (60) along the signal recording surface;
• acceleration means (55), when said information reading means (60) is focusing on a signal recording surface of one of said plurality of layers, for generating an acceleration signal for allowing said information reading means (60) to focus on a recording surface of another of said plurality of layers;
• operation means (55) responsive to provision of a targeted address and targeted layer information for calculating a shift in position of said information reading means (60) from a current address and layer information having information being read by said information reading means;
• and
• control means (55) for driving said drive means to move said information reading means by the shift in position calculated by said operation means and for allowing said acceleration means to generate and provide said acceleration signal to said information reading means to allow said information reading means to focus on a signal recording layer of said targeted layer.

A device reproducing of information recorded on a plurality of layers of an optical disk, comprising:

• information reading means (60) for illuminating said optical disk (1) with a beam and detecting light reflected from said optical disk (1) to read said information;
• interlayer-distance detection means (55) for detecting first spacings between said layers in a mounted said optical disk (1) at a plurality of points different in a distance from a center of said optical disk (1);
• storage means (57) for storing said first spacings detected by said interlayer-distance detection means;
• and
• control means (55) for using said first spacings stored in said storage means to calculate a second spacing between a first layer and a second layer of said optical disk (1) when information is being reproduced from said first layer and for thereby controlling said information reading means to focus said beam on said second layer so that information is reproduced from said second layer when information is being reproduced from said first layer.

A device reproducing information recorded on a plurality of layers of an optical disk, comprising:

• information reading means (60) for illuminating said optical disk (1) with a beam and detecting light reflected from said optical disk (1) to read said information;
• acceleration means (55) for generating and providing to said information reading means (60) an acceleration signal for moving said information reading means (60) to change a distance from said optical disk (1) to said information reading means (60);
• and
• deceleration means (55) for generating and providing to said information reading means a deceleration signal variable in magnitude for controlling said information reading means to stop at a position for focusing said beam on a desired layer.

An optical disk device reproducing information from a multilayer optical disk having a plurality of recording layers, comprising:

• a laser (141);
• an optical system including a lens (143) for directing a laser beam from said laser (141) to said multilayer optical disk (1);
• and
• changing means (148) for changing a focal distance of said lens depending on a recording layer having information to be reproduced among said plurality of recording layers.

The optical disk device according to claim to 17, wherein:

• said collimator lens (143) includes
• a first piece of lens (301),
• a second piece of lens (302) provided opposite to said first piece of lens, and
• a transparent member (305) posed between said first and second pieces of lens;
• and
• said changing means (148) changes a refractive index of said transparent member depending on a recording layer having information to be reproduced among said plurality of recording layers.

An optical disk device reproducing information from an optical disk, said disk having the information recorded on respective signal recording surfaces of first and second layers different at least in reflectance, comprising:

• information reading means (60) for illuminating said optical disk (1) with a beam and detecting light reflected from said optical disk (1) to output one of a reproduced signal of said information, a focusing error signal (FE) and a tracking error signal (TE);
• storage means (57) for previously storing a level of one of the reproduced signal of the information, said focusing error signal (FE) and said tracking error signal (TE) of each of said first and second layers output from said information reading means (60);
• and
• identifying means (55) for identifying a layer of interest as one of said first and second layers by comparing one of the reproduced signal of the information, the focusing error signal and the tracking error signal output from said information reading means to a level of said first layer and a level of said second layer stored in said storage means when it is difficult to identify the layer of interest as one of said first and second layers.

An optical disk device reproducing information recorded on a signal recording surface of a plurality of layers an optical disk, comprising:

• information reading means (60) for illuminating said optical disk (1) with a beam and detecting light reflected from said optical disk (1) to read said information;
• acceleration means (55), when said-information reading means (60) is focusing on a signal recording surface of one of said plurality of layers, for generating and providing to said information reading means (60) an acceleration signal to allow said information reading means (60) to focus on a signal recording surface of another of said plurality of layers;
• and
• deceleration means (55) for generating and providing to said information reading means (60) a deceleration signal for controlling said information reading means (60) to stop when predetermined reflected light is not obtained from said information reading means (60) within a predetermined period of time after said acceleration means supplies said acceleration signal to said information reading means (60).

An optical disk device reproducing information recorded on a signal recording surface of a plurality of layers of an optical disk, comprising:

• information reading means (60) for illuminating said optical-disk with beam and detecting light reflected from said optical disk (1) to read said information;
• acceleration means, when said information reading means (60) is focusing on the signal recording surface of one of said plurality of layers, for generating and providing to said information reading means (60) an acceleration signal to allow said information reading means (60) to focus on the signal recording surface of another of said plurality of layers;
• and
• deceleration means for generating and providing to said information reading means (60) a deceleration signal for controlling said information reading means to stop when a predetermined level of reflected light is not obtained from said information reading means after application of said acceleration signal from said acceleration means to said information reading means.