Abstract: A disc cartridge includes a shutter member movably supported by a cartridge main body accommodating a disc and provided with an aperture for laying a part of the major surface to outside across the inner periphery and the outer periphery of the disc. The disc cartridge further includes a holding member having its proximal side rotatably supported within the cartridge main body and adapted for holding the shutter member in a position of closing the aperture. The shutter member includes a plate portion for opening and closing the aperture of the cartridge main body, a mating engaging portion engaged by a part of the free end of the holding member, an inserting portion adapted for being inserted into a shutter opening groove provided in a lateral side of the cartridge main body and a connecting portion for connecting the plate portion and the inserting portion to each other.

Abstract: A disc cartridge including a cartridge body formed with an aperture for exposing at least a part of the signal recording area of an accommodated disc, and a shutter member slidably mounted on the cartridge body for opening or closing the aperture, is disclosed. The cartridge body is provided with a shutter opening groove extending along the sliding direction of the shutter member which is parallel to the direction of insertion of the disc cartridge into a recording and/or reproducing apparatus adapted for recording and/or reproducing information signals on or from the disc, and a mistaken insertion inhibiting groove extending parallel to the shutter opening groove and having a length shorter than that of the shutter opening groove. Mistaken insertion of the disc cartridge may be inhibited by mistaken insertion inhibiting pins provided in the recording and/or reproducing apparatus for mating with each of these grooves.

Abstract: A disc recording and reproducing apparatus for use with a disc cartridge which includes an exterior indicator for indicating a reflectance of an optical disc housed in a cartridge body thereof, the disc recording and reproducing apparatus including a detector for detecting the exterior indicator and a setting control circuit for initially setting an output level of a laser light irradiated on the optical disc based on a detection output from the detector before beginning recording or reproducing operations.

Abstract: An objective lens driving device, and the method of its manufacture, comprising an objective lens, a stationary support, a holder carrying one or more driving coils and having mounted thereon an objective lens, a plurality of arm-shaped resilient supporting members, each having one end side mounted on the holder and having an opposite end side mounted to the stationary support so that the resilient supporting members are movable in a direction parallel to the optical axis of the objective lens, each of the resilient supporting members being arranged between the holder and the stationary support parallel to each other along a direction perpendicular to the optical axis of the objective lens and being formed of electrically conductive material, with at least two of the resilient supporting members being directly connected to melted end portions of the one or more driving coils.

Abstract: An objective lens actuating device including an objective lens, a bobbin, an elastic support and a magnetic circuit. The bobbin has the objective lens mounted at its one end and first and second coils at its other end. The elastic support has its one end mounted on an end of the bobbin carrying the objective lens and has its other end supported by a fixation portion, and supports the bobbin for deflection in a direction parallel to the optical axis of the objective lens and in a direction orthogonal to the optical axis. The magnetic circuit drives the bobbin at least in a direction parallel to the optical axis of the objective lens and in a direction orthogonal to the optical axis by a magnet carrying the yoke and the first and second coils mounted on the bobbin.

Abstract: A disc cartridge having a cartridge main body and a shutter member is disclosed. The cartridge main body contains a disc-shaped recording medium and includes an aperture formed in one of a pair of planar portions for exposing at least an information recording area of the disc-shaped recording medium to outside. The shutter member opens or closes the aperture and is movably mounted on the cartridge main body. A braille representing portion for indicating the type of the disc-shaped recording medium is formed on a shutter member of the disc cartridge, a container casing containing the disc cartridge or an index sheet arranged between the disc cartridge and the packaging film sheet and acting as a sheath on which the braille representing portion is formed.

Abstract: A disc cartridge including a cartridge body formed with an aperture for exposing at least a part of the signal recording area of an accommodated disc, and a shutter member slidably mounted on the cartridge body for opening or closing the aperture, is disclosed. The cartridge body is provided with a shutter opening groove extending along the sliding direction of the shutter member which is parallel to the direction of insertion of the disc cartridge into a recording and/or reproducing apparatus adapted for recording and/or reproducing information signals on or from the disc, and a mistaken insertion inhibiting groove extending parallel to the shutter opening groove and having a length shorter than that of the shutter opening groove. Mistaken insertion of the disc cartridge may be inhibited by mistaken insertion inhibiting pins provided in the recording and/or reproducing apparatus for mating with each of these grooves.

Abstract: An objective lens driving device is provided in which a resilient supporting member supporting an objective lens holder mounting an objective lens for elastic displacement in the focusing direction and in the tracking direction has a spring constant control portion for lowering one of the first-order resonant frequency in the focusing direction and the first-order resonant frequency in the tracking direction relative to the other. The spring constant control portion is of a cross-sectional shape having one of the focusing direction and the tracking direction as the long axis. The resilient supporting member is formed by plastic deformation of a starting resilient linear material having a spring constant in the focusing direction equal to the spring constant in the tracking direction. This enables a stable control operation for the objective lens.

Abstract: A magneto-optical disc having an optical-magnetic recording layer, formed on the surface of a transparent base plate opposite its beam incident surface is disclosed, wherein a layer excellent in lubriciousness is formed in superimposition on the optical-magnetic recording layer to enable the magnetic head to be in direct sliding contact with the disc surface to provide for stable recording and improved recording performance as well as to reduce adverse effects caused by deposition of foreign matter such as dust and dirt.

Abstract: In an optical pick-up device adapted for detecting light reflected from a disc by using a photo detector to drive an object lens in focus and tracking directions on the basis of a detected signal of the photo detector, a multi-lens for improving sensitivity and accuracy of the photo detector and a multi-lens holder for holding the multi-lens are provided, wherein the multi-lens holder is such a shape that it traverses a first optical path from a light source to a beam and traverses a second optical path from the beam splitter to the photo detector. Thus, adjustment of the spacing between the multi-lens and the photo detector can be facilitated, and the shape of the optical pick-up device itself can be thin and light-weight.