Abstract: An optical pickup apparatus comprising: a diffraction grating configured to diffract laser light from a laser diode so that signals recorded in first and second optical discs are selectively reproduced, thicknesses of protective layers between surfaces and signal recording surfaces of the first and second optical discs being different from each other; a polarization beam splitter configured to divide laser light from the diffraction grating into first and second laser lights whose light amounts are substantially the same; a first objective lens configured to focus the first laser light onto the signal recording surface of the first optical disc; a second objective lens configured to focus the second laser light onto the signal recording surface of the second optical disc; and a photodetector configured to be applied with return lights of the first and second laser lights reflected from the signal recording surfaces of the first and second optical discs.

Abstract: In a viewfinder for a single lens reflex camera, in which a focused image of an object formed on a ground glass by a photographing lens is transmitted to an ocular optical system through a pentagonal prism or a pentagonal mirror and an information image displayed on an indication surface of an indication block is transmitted to the pentagonal prism or pentagonal mirror, through an indication prism, so that the object image and the information image are indicated in the finder view field of the ocular optical system, the indication surface of the indicator is inclined with respect to a direction perpendicular to an incident surface of the image-erecting optical member toward the incident surface, and an angle between the indication surface of the indicator and the incident surface of the image-erecting optical member is smaller than 90°.

Abstract: The recording method for an optical recording medium with a laminated structure with a ROM layer, from which data having been recorded beforehand can be read out, and a RAM layer, from which data is read out and in which data is recordable, includes: emitting laser light that has two or more pulses per record unit of a RAM record mark, which is recorded as data on the RAM layer, thereby recording the RAM record mark.

Abstract: First and second print layers extend on the surface of a medium body in a recording medium. The first print layer has a first thickness. The second print layer has a second thickness larger than the first thickness. A print protection layer covers over the first and second print layers on the surface of the medium body. An inclined surface is defined on the surface of the print protection layer. The inventors have found that a print layer has various thickness based on the kind of colors. The difference in the thickness causes a step on the surface of the print layer at the boundary between the different colors. The inclined surface is established on the surface of the print protection layer based on the step. A smooth relative movement can thus be realized between a head and the surface of the print protection layer.

Abstract: Multiple recording and simultaneous regeneration are performed using a storage medium comprising phase pits and a recording layer so that ROM and RAM can be regenerated simultaneously. When data is recorded to RAM while regenerating ROM using the concurrent ROM/RAM recording medium, the start and the end of recording to RAM is controlled using the recording start and recording end signals of the ROM. Therefore the content recording position of the RAM with respect to the content of ROM can be equalized, the delay can be controlled, and the virtual session function and the multiple recording function can be easily implemented at low cost.

Abstract: The magneto-optical recording medium is comprised of a phase pit substrate/dielectric layer/recording layers/dielectric layer/reflection layer and a ROM and RAM can be simultaneously regenerated. The shape of the phase pit is constructed to be 5<100×Ip/Im<22 where Im is a reflection level on the mirror face and Ip is a phase pit signal output of the shortest mark when a regeneration light having polarization in a direction horizontal to the track direction of the medium is irradiated. Since the jitter of both the magneto-optical recording/regeneration signals and phase pit signals can be suppressed within an optimum range, the quality of the regeneration signals when ROM and RAM are simultaneously regenerated can be improved.

Abstract: An optical recording medium includes a substrate having phase pits, a reflective layer that reflects a light beam emitted to the substrate and the phase pits, and a reflectivity reducing layer that reduces the reflectivity of the reflective layer on a light-incident side of the reflective layer. A dielectric layer is formed as the reflectivity reducing layer so that a refractive index varies. In another variation, a metal layer is used as the reflectivity reducing layer, which is formed of a metal film with a higher refractive index than that of the reflective layer.

Abstract: A mark is formed on a resist disk according to set values of indexes representing magnitudes of causes that affect deterioration in a quality of a playback signal at the time of signal playback. A ROM media is manufactured using the resist disk.

Abstract: A known error signal is recorded in a recording medium for testing. When manufacturing a reproducing apparatus, the recording medium for testing is used to check whether there is a deficiency in the reproducing apparatus.

Abstract: A recording medium including a resin substrate having a first thermal expansion coefficient, a center hole, a first surface, and a second surface opposite to the first surface, a recording layer formed on the first surface of the resin substrate and having a recording region, an inner nonrecording region formed inside the inner periphery of the recording region, and an outer nonrecording region formed outside the outer periphery of the recording region, and a protective layer formed on the second surface of the resin substrate except an inner peripheral region having a predetermined range from the center hole, the recording region, and the outer nonrecording region. The thermal deformation suppressing layer has a second thermal expansion coefficient smaller than the first thermal expansion coefficient.

Abstract: A magnetic film is formed over phase pit sequences in a recording medium. Recording marks are established in the magnetic film in accordance with the direction of the magnetization. A laser beam is utilized to read out information from the phase pit sequences. The laser beam is also utilized to read out information based on the recording marks. The minimum mark size of the recording marks is set larger than minimum pit length in the phase pit sequences. The recording medium allows minimization of the influence of the phase pit sequences during the readout of information based on the recording marks as compared with a recording medium having the minimum pit length equal to the minimum mark size. Information can be read out based on the recording marks with a sufficient accuracy even when the minimum pit length gets smaller in the phase pit sequences.

Abstract: The inventor observed the electric signal output from a photodetector in the readout of RAM information. It has been confirmed that the electric signal includes a reproduced waveform of a relatively larger first amplitude value and a reproduced waveform of a second amplitude value smaller than the first amplitude value. The reproduced waveform of the second amplitude value synchronizes with the reproduced waveform of the first amplitude value. The inventor revealed a correlation between the ratio between the first and second amplitude values and a birefringent difference between first and second birefringent values. The satisfaction of the correlation leads to a reliable realization of jitter equal to or smaller than 8% in the readout of information based on recording marks. The recording medium of this type enables realization of recordation and reproduction of information with a high accuracy based on the recording marks.

Abstract: A storage apparatus, capable of record or reproduce of an optical information recording medium in which ROM information is recorded with phase pits and RAM information is recorded on top of a recording region of the phase pits, has a main controller that, when the output of the recording information detection system—a system for detecting reflected light of a laser beam from the optical information recording medium and generating signals corresponding to ROM and RAM information—simultaneously contains ROM and RAM signals corresponding to ROM and RAM information, performs negative feedback control of a semiconductor laser emission using ROM signal in the output of the recording information detection system and performs control so as to obtain read-out and played-back ROM signal from the output of an optical intensity detection system for detecting the intensity of the laser light.

Abstract: In a viewfinder for a single lens reflex camera, in which a focused image of an object formed on a ground glass by a photographing lens is transmitted to an ocular optical system through a pentagonal prism or a pentagonal mirror and an information image displayed on an indication surface of an indication block is transmitted to the pentagonal prism or pentagonal mirror, through an indication prism, so that the object image and the information image are indicated in the finder view field of the ocular optical system, the indication surface of the indicator is inclined with respect to a direction perpendicular to an incident surface of the image-erecting optical member toward the incident surface, and an angle between the indication surface of the indicator and the incident surface of the image-erecting optical member is smaller than 90°.

Abstract: A worm gear is provided on a rotating shaft of an AF motor. A first supporting cylinder includes a gear portion and a receiving portion. A wheel gear, which is in engagement with the worm gear, is formed on an outer surface of the gear portion. A slit is formed at the receiving portion. A second supporting cylinder includes a supported portion which is placed in the receiving portion of the first supporting cylinder, and a receiving portion which supports an AF coupler. A gear is in engagement with a portion which connects the supported portion and the receiving portion of the 2nd supporting cylinder. A clutch spring is wound around the supported portion, being in contact with the outer surface of the supported portion. Both ends of the clutch spring cross each other and are in engagement with a pair of walls, of the slit, which are parallel to an axis of the receiving portion.

Abstract: A magneto-optical storage medium that protects against the effects of cross-talk, making it possible to further reduce the level of track density, and which also makes it possible to conduct high-density recording/playback with a reduced magnetic field for erasure and a favorable level of playback signal quality. More specifically, a magneto-optical storage medium, which includes at least the following laminated layers, in the following order: a playback layer, a non-magnetic layer, a transfer layer, a cut-off layer, and a recording layer. The playback layer preferably displays easy in-plane magnetization characteristics within the monolayer at room temperature, and the transfer layer and the recording layer each have easy magnetization characteristics in the vertical direction of the monolayers at room temperature when each layer is considered as a monolayer.

Abstract: An optical disc has a recording structure consisting of an ROM section and an RAM section which are preferable for multiplexing recording/reproduction of music information and the like On the optical disc, the ROM section where information has been recorded by a phase pit using the light reflectance and the RAM section on/from which recording and reproduction can be preformed are arranged in layers and information recorded in the ROM section and the information recorded in the RAM section are synchronously reproduced. The RAM section is divided into a plurality of information recording areas from which information can be reproduced synchronously with the ROM section. While reproducing music information from the ROM section, music information such as music by separate musical instruments is multiplexedly recorded on the RAM section and multiplexedly reproduced when necessary.

Abstract: A magneto-optical storage medium that protects against the effects of cross-talk, making it possible to further reduce the level of track density, and which also makes it possible to conduct high-density recording/playback with a reduced magnetic field for erasure and a favorable level of playback signal quality. More specifically, a magneto-optical storage medium, which includes at least the following laminated layers, in the following order: a playback layer, a non-magnetic layer, a transfer layer, a cut-off layer, and a recording layer. The playback layer preferably displays easy in-plane magnetization characteristics within the monolayer at room temperature, and the transfer layer and the recording layer each have easy magnetization characteristics in the vertical direction of the monolayers at room temperature when each layer is considered as a monolayer.

Abstract: The recording method for an optical recording medium with a laminated structure with a ROM layer, from which data having been recorded beforehand can be read out, and a RAM layer, from which data is read out and in which data is recordable, includes: emitting laser light that has two or more pulses per record unit of a RAM record mark, which is recorded as data on the RAM layer, thereby recording the RAM record mark.

Abstract: A magneto-optical storage medium that protects against the effects of cross-talk, making it possible to further reduce the level of track density, and which also makes it possible to conduct high-density recording/playback with a reduced magnetic field for erasure and a favorable level of playback signal quality. More specifically, a magneto-optical storage medium, which includes at least the following laminated layers, in the following order: a playback layer, a non-magnetic layer, a transfer layer, a cut-off layer, and a recording layer. The playback layer preferably displays easy in-plane magnetization characteristics within the monolayer at room temperature, and the transfer layer and the recording layer each have easy magnetization characteristics in the vertical direction of the monolayers at room temperature when each layer is considered as a monolayer.