Pioneer Electronic Corporation

Pioneer Video Corporation

Tomoyoshi Ikeya

Takashi Nishio

Chiharu Koshio

Hidetoshi Yokosawa

Naoki Okuyama

Mitsuru Itamochi

An optical mother disc recording apparatus is disclosed, which can effectively solve problems including a decrease in film thickness and the like and can be miniaturized. The optical mother disc recording apparatus comprises a turntable for supporting an optical mother disc having a transparent substrate on which a photoresist layer is formed; a motor for rotating and driving the turntable; and optical means for irradiating a laser beam modulated by an information signal onto the optical mother disc, wherein the transparent substrate has a thickness within the range from 0.4 mm to 4.0 mm and a diameter within the range from 70 mm to 400 mm, and the turntable is capable of being in contact with an area on the inside and/or outside of a recording area of the optical mother disc. The outermost radius of the turntable is smaller than the innermost radius of the recording area of the optical mother disc.

Turntable for optical recording disc recording apparatus

An optical apparatus including a luminous flux shaping filter for converting a shape of an incident beam without bending an optical path of the incident beam. A light beam emitted from a focusing laser source comprising a semiconductor laser is converted into a parallel light beam by a collimator lens, and then enters the luminous flux shaping filter. The luminous flux shaping filter is positioned on an optical path in the apparatus in the manner that a major axis of an oval light beam from the collimator lens is perpendicular to a longitudinal area in which the transmittance is the highest in the filter. As a result, the luminous flux shaping filter converts the oval light beam into a substantially circular light beam without bending an optical path of the light beam.

Optical apparatus having a luminous flux shaping filter

A master optical disk recording apparatus forms a train of pits on a recording layer of a master optical disk by a laser beam which is emitted from the laser light source and is modulated by an acousto-optic modulator. An objective lens in the recording apparatus consists of a finite conjugate type lens and a convergence point on the acousto-optic modulation element where the laser beam is converged by a convergence lens is positioned outside of the focal point of the objective lens at the incidence side thereof.

Master optical disk recording apparatus

An optical reproducing system has a first optical path from a light source to an optical disc, and a second optical path from the optical disc to a photodetector. An objective lens is provided in the first optical path for forming an a non-collimated beam applied to the optical disc. A profile conversion filter having an angle dependent transmittance characteristic is provided between the objective lens and the optical disc.

Optical filter with light transmittance dependency on incident angle

An optical axis monitoring apparatus for monitoring a variation in the optical axis of light beams in an optical system. The apparatus includes a light source for generating a light beam to propagate along a first optical path. A diffraction optical element is disposed along the first optical path for diffracting the light beam into at least two orders of diffraction. At least one of the orders of diffraction propagates along the first optical path and another of the orders of diffraction propagates along a second optical path. A first monitoring element id disposed along the first optical path between the light source and the diffraction optical element for monitoring the first light beam and generating an incoming beam signal in response to light incident thereon. The incoming beam signal being indicative of the condition of the first light beam. A second monitoring element is disposed opposite the diffraction optical element from the first monitoring element and along said the second optical path. The second monitoring element is for receiving light diffracted into the other of the orders of diffraction by the diffraction means and generating an outgoing beam signal in response to light incident thereon. The outgoing beam signal is indicative of the condition of the light beam emanating from the diffraction optical element.

Optical axis monitoring device

A light beam spot size measuring device comprises an optical magnifying system. The magnifying system receives an image of the recording light beam spot formed within an optical recording apparatus, and magnifies it. Then the converter receives the magnified image of the beam spot formed on the pickup surface thereof so as to produce an output signal representing the size of the beam spot. An attenuator device attenuates the intensity of the image of the laser beam spot during magnification. The image of the beam spot therefore can be currently measured on the basis of the output signal even with the high intensity of the recording light beam.

Device for measuring size of light spot

A device for monitoring the amount of deviation of a light beam in an optical system with which the freedom of design of the system is significantly improved. For each position at which the amount of deviation is to be measured, a beam splitter is provided to divide the light beam at that point into a main beam and a sub-beam. The sub-beam is applied to an optical position detector which detects the amount of deviation of the sub-beam from a predetermined position on the detector, that deviation being related to the amount of deviation of the main beam from its designated optical path. The output of the position detector is used to correct the position of the main beam.

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Yamanashi, Japan

Tomoyoshi Ikeya