Multiple layer disk reproducing apparatus, and apparatus for reproducing information record medium

In an information reproducing apparatus for reproducing information a multiple layer disk, a method of preparing for reproducing the information from the multiple layer disk, the multiple layer disk comprising a plurality of layers including at least a first layer and a second layer, the information being recorded on each of the first layer and the second layer, the information reproducing apparatus comprising:

• a light emitting device that emits a light beam to the first layer or the second layer;
• an objective lens that focuses the light beam on the first layer or the second layer;
• a focus servo device that carries out a focus servo control for controlling a focal position of the light beam with respect to the first layer or the second layer;
• a tracking servo device that carries out a tracking servo control for controlling a position of the light beam in a radial direction of the multiple layer disk with respect to the first layer or the second layer;
• a reproducing device that reads the information recorded on the first layer or the second layer using the light beam and that reproduces the read information under the focus servo control and the tracking servo control;
• a memory device that stores various values, the method comprising the processes of:
• determining a first gain value to be used for the focus servo control with respect to the first layer, by detecting a focus error signal with respect to the first layer;
• determining a second gain value to be used for the tracking servo control with respect to the first layer, by detecting a tracking error signal with respect to the first layer;
• determining a third gain value of an RF signal with respect to the first layer;
• determining a fourth gain value to be used for the focus servo control with respect to the second layer, by detecting a focus error signal with respect to the second layer;
• determining a fifth gain value to be used for the tracking servo control with respect to the second layer, by detecting a tracking error signal with respect to the second layer;
• determining a sixth gain value of an RF signal with respect to the second layer;
• and
• storing the first through sixth gain values into the memory device,
• wherein the processes of determining the first through sixth gain values and the process of storing the first through sixth gain values are carried out before a start of reproducing the information from the multiple layer disk.

In an information reproducing apparatus for reproducing information from a multiple layer disk, a method of preparing for reproducing the information from the multiple layer disk, the multiple layer disk comprising a plurality of layers including at least a first layer and a second layer, the information being recorded on each of the first layer and the second layer the information reproducing apparatus comprising:

• a light emitting device that emits a light beam to the first layer or the second layer;
• an objective lens that focuses the light beam on the first layer or the second layer;
• a focus servo device that carries out a focus servo control for controlling a focal position of the light beam with respect to the first layer or the second layer;
• a tracking servo device that carries out a tracking servo control for controlling a position of the light beam in a radial direction of the multiple layer disk with respect to the first layer or the second layer;
• a reproducing device that reads the information recorded on the first layer or the second layer using the light beam and that reproduces the read information under the focus servo control and the tracking servo control;
• a memory device that stores various values, the method comprising the processes of:
• determining a first equalizer value to be used for the focus servo control with respect to the first layer, by detecting a focus error signal with respect to the first layer;
• determining a second equalizer value to be used for the tracking servo control with respect to the first layer, by detecting a tracking error signal with respect to the first layer;
• determining a third equalizer value to be used for the focus servo control with respect to the second layer, by detecting a focus error signal with respect to the second layer;
• determining a fourth equalizer value to be used for the tracking servo control with respect to the second layer, by multiplying the second equalizer value by a ratio of the third equalizer value to the first equalizer value;
• and
• storing the first through fourth equalizer values into the memory device,
• wherein the processes of determining the first through fourth equalizer values and the process of storing the first through fourth equalizer values are carried out before a start of reproducing the information from the multiple layer disk.