Reproduction apparatus and focus jump method

A focus jump method of giving a focus jump drive signal including a kick signal and a brake signal to a shaft sliding type focus actuator, which holds an object lens serving as an output end of laser beams in a direction in which the object lens approaches and separates from a recording medium, and executing focus jump in order to shift a focus state of laser beams from a state of focus on a certain recording layer to a state of focus on another recording layer with respect to a recording medium having plural recording layers for recording or reproducing information by irradiation of laser beams, comprising:

• a kick drive force increasing step of increasing a kick drive force of the kick signal for causing the focus actuator to start focus jump movement from an initial value;
• a kick signal level holding step of maintaining the kick signal at a predetermined level;
• and
• a brake signal generating step of generating the brake signal for causing the focus actuator to stop the focus jump movement.

A reproduction apparatus that reproduces information recorded in a recording medium having plural recording layers, comprising:

• an optical head that irradiates laser beams on the respective recording layers with an object lens as an output end and detects reflected light information of the laser beams to read out information recorded in the respective recording layers;
• a shaft sliding type focus actuator that holds the object lens to be movable in a direction in which the object lens approaches and separates from the recording medium;
• a focus servo section that generates a focus servo drive signal on the basis of a focus error signal, which is obtained from the reflected light information read out by the optical head, and drives the focus actuator such that a focus state of the laser beams is kept in a state of focus on a recording layer on which the reproduction is performed;
• and
• a focus jump control section that generates a kick signal for starting focus jump movement by the focus actuator and a brake signal for ending the focus jump movement as focus jump drive signals for shifting from the state of focus on a certain recording layer to a state of focus on another recording layer, the kick signal being generated as a signal, a kick drive force of which rises from an initial value.