Abstract: A multi-disk player according to the invention has a disk table which comprises (1) a large size disk mounting section on which a large size disk is mounted, (2) a turn table rotatable about an axis which is a predetermined eccentric distance away from the axis of the large size disk mounting section. The turn table includes thereon a plurality of small size disk mounting sections on each of which a small size disk is placed. The eccentric distance is determined such that the axis of each small size disk mounting section is made to coincide with the axis of the large size disk mounting section by rotating the turn table.The player having such an arrangement has a disk driving device whose circuit structure is simplified, and solely plays a plurality of types of disks having different diameters such as CDs and LDs.Further the player plays a disk arbitrarily selected from a plurality of small size disks and successively plays a plurality of small size disks.

Abstract: A tilting mechanism for the optical pickup unit of an optical information record/playback apparatus such as a video disk player. The optical pickup and a support member for slidably supporting the pickup are tilted together by a tilting servocontrol. The tilting mechanism includes a movable fulcrum about which the optical pickup and the support member are tilted. The fulcrum is moved depending on the position of the optical pickup or on a focusing error signal, so that the tilting servo-control is performed when the fulcrum is in an appropriate position with respect to the distance between the pickup and the disk.

Abstract: Bar code readers using laser diodes conserve electrical power and limit output laser radiation to levels required by governmental regulation (1 milliwatt average power) by utilizing a laser diode having a output optical power vs laser current characteristic which has a slope efficiency (the ratio of the change in power to the change in current, .DELTA.P/.DELTA.I, which is less than 1 in the region where stimulated (laser) emission occurs. The laser is operated with current pulses having a duty cycle less than 100%, and preferably in the range from 50% to 20% in the stimulated emission region of its characteristic, such that the average output laser power does not exceed the level required by government regulations (1 mw) while the laser output during the pulses is greater than 1 mw.

Abstract: A recording and/or reproducing apparatus using a record bearing medium contained in a cassette which is provided with at least one positioning hole formed therein. The apparatus is provided with an engaging member which is engageable with the positioning hole for loading the cassette at a predetermined position within the apparatus; an urging member for urging the engaging member to engage with the hole; and a disengaging member for selectively disengaging the engaging member from the hole. These parts are arranged to ensure smooth loading and unloading operations on the cassette.