Abstract: To move an object lens out of focalization on a layer and to accelerate it upwardly, a drive signal DRV is set HIGH, and a focus OPEN signal is set LOW. After a value a counter exhibits at this time is held in a register T1, the counter is reset at zero. Then a value the counter exhibits upon FZC+ being LOW is held in a register T2.sub.A, and a value the counter exhibits upon FZC- being HIGH is held in a register T2.sub.B. The value of a register T3 is calculated from T1 and the average of T2.sub.A and T2.sub.B, and when the counter value becomes equal to the sum of T1 and T3, DRV is set HIGH. After FZC- becomes LOW, OPEN is set HIGH, and the focus jump operation is completed.

Abstract: When an optical disk having a plurality of recording layers is loaded, in which layer-number data is recorded on the recording layer nearest to the signal reading plane and layer I.D. data is recorded on each recording layer, a pickup reads the data recorded on each recording layer. A focus error signal is produced by a quartered detector by using return light from the pickup. A focus search drive circuit generates a focus drive signal. When focalization on a desired recording layer is established during focus search by the focus search drive circuit, the focus search drive circuit is stopped.

Abstract: To move an object lens out of focalization on a layer and to accelerate it upwardly, a drive signal DRV is set HIGH, and a focus OPEN signal is set LOW. After a value a counter exhibits at this time is held in a register T1, the counter is reset at zero. Then a value the counter exhibits upon FZC+ being LOW is held in a register T2.sub.A, and a value the counter exhibits upon FZC- being HIGH is held in a register T2.sub.B. The value of a register T3 is calculated from T1 and the average of T2 and T2.sub.B, and when the counter value becomes equal to the sum of T1 and T3, DRV is set HIGH. After FZC- becomes LOW, OPEN is set HIGH, and the focus jump operation is completed.

Abstract: An optical disk player for reproducing information stored on various types of optical disks, such as video disks and compact disks having diameters different from that of the video disk, for recording audio signals and for recording audio and video signals, wherein a skew sensor detects an inclination of an optical disk relative to an optical pickup, a skew servo mechanism controls the inclination of the optical pickup, relative to the optical disk on the basis of the detected inclination, a disk size detector detects the size of the disks, a disk detector detects signals, recorded in audio and audio/video compact disks indicative of the type of optical disk, and on the basis of the detected outputs from the size detector and the disk detector, the skew servo is effected continuously from the innermost track to outermost track or slightly before the outermost track when the disk is a video disk or audio/video compact disk, but wherein the skew servo is stopped at a predetermined position inwardly of the outer