Abstract: An optical disk drive of the type having a fixed optical unit having a light transmitting hole from which a laser beam is emitted, and a movable head having a light receiving hole from which the laser beam is received, wherein the respective outer edges of the light emitting and receiving holes are surrounded by a pair of annular projections. The annular projections are engageable with each other to provide a seal therebetween when the head is displaced toward the fixed optical unit. The annular projections are preferably made of a cushioning material in which instance they also serve as a cushioning or shock-absorbing member.

Abstract: An apparatus for generating a bias magnetic field to a magneto-optical disk includes a movable magnet which serves to generate a bias magnetic field. A suitable device serves to generate a drive magnetic field to move the magnet. A stopper is engageable with the magnet to stop the magnet at a predetermined position.

Abstract: A liquid crystal compound represented by formula (I): ##STR1## wherein R.sub.1 represents an alkyl group having from 3 to 18 carbon atoms; R.sub.2 represents an alkyl group having from 3 to 18 carbon atoms; X represents ##STR2## (A) and (B) each represents a group selected from the group consisting of ##STR3## and * indicates an optically active center.

Abstract: An objective lens actuator for an optical storage drive includes a cross-sectionally L-shaped torsion plate spring which is fixed at its central portion to an objective lens holder and at its opposite ends to free ends of a pair of parallel spaced, cantilevered plate springs. The torsion plate spring is caused to twist to displace the objective lens holder and an objective lens mounted thereon in the tracking direction. The parallel spaced plate springs are caused to bend to displace the objective lens holder and the objective lens in the focusing direction.

Abstract: Liquid crystal compounds represented by the formula; ##STR1## in which Ra means an alkyl group of 1-20 carbon atoms or an alkoxy group of 1-20 carbon atoms; Rb means an aliphatic alkyl group, a branched alkyl group or an aralkyl group respectively of 1-20 carbon atoms, an alkoxy group of 1-20 carbon atoms, or an alkanoyl methyl group having 1-20 carbon atoms in the alkyl; ##STR2## Z means a fluorinated alkyl or a fluorinated haloalkyl; m is an integer of from 1 to 3; n is an integer of from 0 to 2 where when n is 0, Y is a single bond; and * shows an optically active center, which have a larger spontaneous polarization, high speed of response and good orientation, and show tristable liquid crystal phase.

Abstract: An optical unit actuator for an optical information recording/reproducing apparatus includes an electromagnetic drive mechanism composed of a coil and a magnet cooperative to drive an objective lens mounted on an optical unit. One of the coil and the magnet is secured to the optical unit. The other of the coil and the magnet is held on a fixed unit with an elastic support member disposed therebetween, the fixed unit being immovable as against the movable optical unit. The elastic support member substantially dampens or takes up vibration caused by a reaction force creased as a result of acceleration of the objective lens when the objective lens is driven to follow a dynamic radial runout and an axial deflection of an optical disk. With the elastic support member thus provided, an optical component, a photo-electric transducer or the optical disk which is disposed on the side of the fixed unit is isolated from vibration.

Abstract: The invention lies particularly in novel compounds represented by the general formula; ##STR1## in which Z means CF.sub.3, CHF.sub.2, CH.sub.2 F, CClF.sub.2, CCl.sub.2 F, CHCLF, CCl.sub.3, C.sub.2 F.sub.2 or a perfluoroalkyl group of 3 or more carbon atoms, m and n are same or different with each other and represent an integral of 1-20, which are ferroelectric and chiral smetic liquid crystals of a large spontaneous polarization, a high speed of response and a good orientation, and showing a liquid crystal phase of tristable state and an electoclinic effect to be used as a liquid crystal element superior in an image display response.

Abstract: Ferrelectric chiral smetic liquid crystal compound are provided which have the formula, for example ##STR1## wherein R is a C.sub.1-20 alkyl group.

Abstract: A new tetrastable liquid crystal is provided which is useful for display and switching devices. The liquid crystal has the formula ##STR1## where R.sub.1 is a C.sub.5-18 alkyl group and R.sub.2 is a C.sub.4-15 alkyl group and * is an optically active center.

Abstract: A shutter opening and device includes movable components such as a lever, an actuating pin and a spring all disposed in a guide channel of a cartridge holder into which a disk cartridge is inserted. The device of this construction is low in profile and compact in size and makes it possible to reduce the overall size of a disk drive in which the device is incorporated. With the combination of a straight guide groove and an oblique guide groove formed in the cartridge holder, the actuating pin is movable along a substantially straight path. This enables the user to insert the disk cartridge into the cartridge holder smoothly with a small muscular effort.

Abstract: A liquid crystal compound represented by formula (I): ##STR1## wherein R.sub.1 represents an alkyl group having from 5 to 18 carbon atoms; R.sub.2 represents an alkyl group having from 4 to 15 carbon atoms; X represents a single bond, --O--, ##STR2## and * indicates an optically active center. The compound exhibits three stable states of molecular orientation.

Abstract: There is disclosed herein a recording/reproducing apparatus including a magnetic field supply device for recording and reproducing of information and a cartridge holder for holding a cartridge having therein a recording disc. The apparatus includes a first motor for driving the recording disc when the cartridge is inserted into the cartridge holder, a sliding member adapted to be engaged with the cartridge holder to cause the disc to be disengageable with the first motor, a rotatable lever engageable with the sliding member so as to cause the recording disc to be disengageable with the first motor, and a geared transmission coupled to a second reversible motor and having an engaging portion which is engageable with the rotatable lever to cause the disc to be disengageable with the first motor.

Abstract: There is disclosed herein a ferroelectric liquid crystal electro-optical apparatus of the maxtrix type comprising a liquid crystal cell having first and second electrode substrates which include n striped line electrodes and m striped column electrodes, respectively, facing at right angles each other. A ferroelectric liquid crystal is put in therebetween so as to form n by m indication picture elements. Also included in the apparatus a scanning drive device adapted to supply a scanning signal and a data signal to the n striped line electrodes and the m striped column electrodes, respectively. The ferroelectric liquid crystal shows three stable states in accordance with an application voltage and has a light transmittance with a hysteresis sufficient to a dynamic drive in accordance with increase or decrease in the application voltage in a predetermined voltage range.

Abstract: A compound of ##STR1## (wherein n is an integer from 2 to 15; R' is ##STR2## m is total number of carbon atoms in R' and is an integer from 5 to 12, and * mark shows asymmetric carbon atom) which is useful for an electric indicative element of liquid crystal is provided.

Abstract: The present invention provides a recording disc playback apparatus employing a disc case (1) including: a case body (2) in which a disc-like recording medium (6) is accommodated and which has at one end an opening (7) through which the recording medium (6) is taken out; and a lid (3) which is detachably fitted into the opening (7). This apparatus comprises: a lid releasing means (60) for causing the release of the engagement between the lid (3) and the opening (7) of the case body (2); lid locking means (99, 100) for detachably locking the lid (3); feed means (91, 111 and 114) for feeding the lid locking means (99, 100) and the recording medium (6) within a playback apparatus body; and restriction means (96a, 102, and 102c) for maintaining the lid locking means (99, 100) in an unlocking state within a portion of a feed path along which the feed means (91, 111 and 114) feeds the lid locking means (99, 100).

Abstract: The present invention provides a recording disc playback apparatus employing a disc case (1) including: a case body (2) in which a disc-like recording medium (6) is accommodated; and at one end a lid (3) which is detachably fitted into the opening (7). This apparatus comprises: a playback apparatus body (50) including a playback means; lid release means (107, 108) for causing the release of the engagement between the lid (3) and the case body (2); clamp means (90) for clamping the recording medium (6); and a feed means by which the clamp means (90) is fed within the playback apparatus body (50) and the recording medium (6) is drawn out of the case body (2) so as to take a predetermined playback position. In the apparatus of this invention, when a user merely inserts the disc case (1) into the playback apparatus body (50), the recording medium (6) is automatically and positively taken out of the case (1) for reproduction purposes.

Abstract: The present invention relates to a recording disc reproducing device wherein a disc like recording medium is held in a disc case having an opening at one end thereof, for insertion and removal of the disc like recording medium. The disc like recording medium remains inside the body of the device after pulling out the disc case which has been inserted to a predetermined position in the body of the device. The opening of the disc case inserted into the body of the device is expanded to be opened by an opening mechanism and after the disc case has been inserted part way into the device the disc case is secured by a latch connected to the opening mechanism. Further movement of the disc case into the device is possible after the latch engages the disc case.

Abstract: A disk clamping mechanism for disk recording and reproducing devices of the type in which when a disk cartridge with a disk enclosed therein is inserted into the device the disk clamping mechanism is actuated to clamp the raised groove guard formed around the rim of the disk so that when the cartridge is pulled out of the device the disk remains therein. The clamping mechanism includes a pair of clamping fingers with projections adapted for engagement with the groove guard when the forces pulling out the cartridge are transmitted to the disk. A linkage or a mechanism comprising a wedge and tapered surfaces is operatively connected to the clamping fingers in such a way that when a pulling force is exerted on the disk and the clamping fingers, the linkage or mechanism causes the clamping arms or fingers to move further toward each other, thus exerting a stronger clamping force on the disk.