Abstract: A plasma processing apparatus has a plurality of annular permanent magnets arranged concentrically with the same polarity in the circumferential direction at the atmosphere side of a second electrode arranged opposite to a stage on which a specimen is placed. Arrangement is provided so that the magnets located adjacent radially have opposite polarity. Furthermore, permanent magnets are arranged at the outer circumference of a vacuum vessel corresponding to a plasma generation chamber portion. A plasma processing apparatus can be provided that allows formation of uniform plasma over a large area and uniform processing of a specimen of a large diameter.

Abstract: A device for measuring characteristic values of an optical pickup and/or an optical disc capable of detecting tracking signals for measuring characteristic values even if optical disc rotation is not subjected to eccentricity. The device for measuring characteristic values of an optical pickup and/or an optical disc 1 samples outputs of photodetectors of an optical pickup 2 as signals A to F directly by a sample-and-hold circuit 8 and an analog-to-digital converter 10 to store the resulting digital data in a second memory 11. An arithmetic-logic unit 12d measures tracking error signals based on the digital data stored in the second memory 11. A signal generating circuit 25 then sends a sine wave signal to a tracking coil 2b for moving the laser light illuminated on the optical disc along the radius of the disc.

Abstract: A plasma is supplied from a plasma source to a space between an upper electrode plate and a lower electrode plate disposed opposite to and in parallel with the upper electrode plate when producing a plasma in the space between the electrode plates for plasma processing by applying radio-frequency power to the electrode plates. The plasma source produce a plasma by inductively coupled discharge, radio-frequency discharge or microwave discharge. A plasma processing apparatus is obtained which is capable of producing a parallel-plate plasma by discharge in a space of a relatively low pressure and is capable of processing a large diameter workpiece uniformly at a high processing rate.

Abstract: In an optical head having a plate-like half mirror functioning both as a beam splitter and for producing an astigmatism usable in detecting a focusing error, an optical element is provided for correcting a coma introduced by the half-mirror. Such optical element for correcting coma desirably includes a plate-like element inclined oppositely to the plate-like half mirror in respect to an optical axis of the head.

Abstract: A photosensor device and an optical pickup device incorporating the photosensor device are advantageously used in an optical compact disc player of the type where the optical pickup device is driven along a path at an acute tilt angle relative to the sides of a rectangular casing. The photosensor has a plurality of photosensitive elements aligned in a first direction and a plurality of terminal leads extending parallel to each other and perpendicular to a second direction so that the photosensor may be mounted on a circuit board in a conventional configuration to save space. Within the optical pickup device, the photosensitive elements are aligned at a mounting angle which is a function of the tilt angle so that the three optical beams are received thereon in the proper orientation.

Abstract: In an optical reproducing apparatus a divergent beam from a semiconductor laser light source is collimated to form a parallel light beam that is converged by an objective lens and focussed on an optical record medium. The light beam is reflected by the optical record medium and introduced into a signal photodetector so as to provide a reproduced signal. A phase type diffraction grating between the semiconductor laser light source and a beam splitter separates the laser beam from the semiconductor laser light source into zero, plus first and minus first order diffracted beams. A pair of tracking photodetectors receive reflected beams of the plus first and minus first order diffracted beams reflected by the optical record medium and then by the beam splitter.

Abstract: In an optical disc player or other apparatus in which a light beam is directed through an objective lens to be focused thereby at a record medium surface for optically reading information recorded in a track on such surface; the objective lens has its central axis offset in respect to the longitudinal axis of a cylindrical body forming part of a movable assembly and through which the light beam passes axially, and such cylindrical body is both angularly displaceable about its longitudinal axis and axially displaceable relative to a guide bearing forming part of a fixed assembly to correct for tracking errors and for focusing errors, respectively. The fixed assembly further includes a magnetic circuit generating a magnetic field which intersects coils included in the movable assembly to receive focusing error and tracking error signals, respectively.

Abstract: A device for supporting and positioning the objective lens in an optical reading apparatus, such as, a video disc player, comprises a first pair of parallel leaf springs attached at one end thereof to a fixed support member for motion parallel to a record medium surface. A movable frame is attached to the other ends of the first springs, and a second pair of leaf springs movable perpendicularly to the record medium surface extend from the frame, the second springs being generally parallel to and between the first pair but with their faces perpendicular to those of the first pair. The objective lens is mounted at the free ends of the second pair of springs, and is movable electromagnetically in orthogonally related directions by means of coils and magnets associated with the objective lens and with the frame.

Abstract: An optical tracking apparatus for tracing a spiral track on a recording disk includes an optical pickup device having a semiconductor laser and a photoelectric conversion element; an arm device pivotally mounted to an arm shaft with the pickup device being mounted to the free end thereof to thereby move substantially along the radial direction of the recording disk; sectorial arm drive coil attached to a rear end portion of the arm device and having a current path loop in parallel with the rotational plane of the arm device; and a pair of stationary magnetic field forming devices, each formed of a respective yoke and permanent magnet assembly, the yokes having respective air gaps in which magnetic fields in opposite directions to each other are formed, the arm drive coil being arranged to move in the air gaps and being supplied with an arm drive signal and a tracking error correction signal for causing the pickup device to trace the track.

Abstract: A multi-axis movable mirror device includes a mirror, a flexible coupling to couple the mirror to a fixed member to allow the mirror to freely rotate about a plurality of axes, a bobbin integrally secured to the mirror, a number of coils wound on the bobbin at different locations and a number of sets of magnets opposing the coils wound on the bobbin. The mirror is rotated about selected axes by supplying control currents to selected coils.