Funai Electric Company Ltd.

Ryotaro Nakagawa

Teruaki Sogawa

Toyoshi Nogami

Masanori Takahashi

Yasunori Kuwayama

Takayuki Murakami

Hideaki Funakoshi

Tetsuo Nishidate

Yoshiaki Ukawa

A laser holder holds a semiconductor laser that has a metal frame part in which a semiconductor laser chip is mounted on one surface, and a resin part provided so as to surround the semiconductor laser chip. The laser holder is provided with an insertion part into which the semiconductor laser is inserted. The insertion part is provided with an aperture part that allows the resin part of the semiconductor laser inserted into the insertion part to be pushed from the exterior, and a wall surface part against which a reverse surface of the one surface of the metal frame part is pressed in a case where the resin part is pushed from the exterior.

Laser holder and optical pickup provided with same

An optical disc apparatus comprises, an optical pickup, a signal extracting unit for reading address information and an RF signal from an optical disc based on signal read by the optical pickup, and a main controller for performing jitter control and focus control. At an initial reading of the optical disc, the main controller determines whether an address information detector succeeds in reading the address information. If not successful (NO in S), the main controller offsets a defocus position to two points in plus and minus directions from a defocus position giving best jitter (S), calculates an approximate curve of signal level characteristics with a peak value (S), and adjusts and allows the defocus value to correspond to this peak value (S). If the optical disc apparatus cannot read address information, depending on the defocus value, it increases the signal level of the address information by the defocus position adjustment.

Optical disc apparatus

A method for designing an optical pickup is provided. The optical pick includes a monolithic laser diode that emits a laser light beam for DVD recording and a laser light beam for CD playback, two photodetective portions, and an objective lens, for each of the emitting portions of the monolithic laser diode for emitting the DVD recording and CD playback laser light beams respectively, the specification of the error of the emission direction thereof is determined according to the following formula: |(&#x394;&#x3b8;&#x22a5;&#xd7;&#x394;&#x3b8;&#xd7;Dpd/Dob&#x2212;&#x394;&#x3b8;&#x22a5;&#xd7;&#x394;&#x3b8;&#xd7;Dpd/Dob)&#xd7;Kpd|&#x2266;&#x3b1;, where, '1' corresponds to the DVD recording laser light beam and '2' corresponds to the CD playback laser light beam, &#x394;&#x3b8;&#x22a5; represents the emission angle; &#x394;&#x3b8; represents the sensitivity; Dob represents the diameter of the light beam; Dpd represents the diameter of the spot formed by the light beam; Kpd represents the sensitivity; and &#x3b1; represents the tolerable value.

Method for designing an optical pickup

In an optical head according to the present invention, an act base on which an objective lens is arranged is formed in a rectangular shape with through holes formed in four corners thereof. A base on which a collimating lens is arranged has projections to engage with the through holes in correspondence with the through holes when the act base is arranged. With the through holes of the act base engaged with the projections of the base, an adhesive is injected to the through holes to thereby fix the act base to the base. This improves the accuracy in bonding between the base and the act base, and permits laser light of a more stable intensity accordingly to be irradiated to the optical disc, thus permitting suppressing failure involved in data recording or reading.

Optical head and optical disc device provided therewith

A lens holder is provided with a focusing coil for urging the lens holder in a focusing direction and tracking coils for urging the lens holder in a tracking direction in cooperation with magnets. A magnet is disposed in a space where the focusing coil and the tracking coil are opposed to each other in a through hole of the lens holder, such that a magnetized surface on one surface side of the magnet is opposed to the focusing coil and a magnetized surface on the other surface side thereof is opposed to the tracking coil.

Optical pickup

An optical pickup in which a plateprovided with a photodiodeis bonded to an optical benchthrough an adhesive agent layerin a state in which a minute gap &#x3b1; is maintained between the plateand the optical bench. Circular through holesare formed in advance at a plurality of portions of the plate. The adhesive agent layeris formed as an adhesive agent injected into the through holesat the plurality of portions is forced out downward through the through holesand is cured in the state of having reached an upper surfaceof the optical bench. The amount of the adhesive agent injected with respect to each of the through holes is controlled so as to be fixed.

An optical pickup of an optical disc apparatus has a lens holder for holding an objective lens is pivoted with a guide shaft slidably in a direction in parallel with an optical axis of the objective lens and rotatably around the guide shaft in a direction perpendicular to the optical axis. For focusing a laser beam on a data recording face of an optical disc in a focusing on operation, a wobble signal of rectangular waveform having a predetermined voltage and a predetermined frequency is applied to a tracking coil for reciprocally displacing the lens holder in the direction perpendicular to the optical axis, while a focusing coil is driven for moving the lens holder in the direction in parallel with the optical axis. Thus, the lens holder can be moved smoothly along the guide shaft, so that the possibility of failure of the focusing the laser beam on the optical disc can be reduced drastically.

An objective lens has an actuator base and a lens holder for supporting an objective lens. The lens holder has a shaft hole. A shaft is disposed on the actuator base and fitted to the shaft hole. A cover is attached to the actuator base so as to cover the lens holder in a manner that the cover comes into contact with or comes close to the top face of the shaft. Protrusions are disposed on an actuator base opposing face and a cover opposing face of the lens holder without contacting the shaft. When the protrusions are contacted with the actuator base and the cover, a predetermined gap is formed between the lens holder and the actuator base and between the lens holder and the cover, the gap is communicated with a space in the cover through the side of the protrusions.

Objective lens unit

In an optical pickup device, an upper plate portion, leg portions and a support shaft are provided in a base member so as to be disposed above a lens holder. A mechanism for adjusting the tilt angle of an objective lens is constituted by lower end surfaces formed out the curved surfaces of the leg portions, and reception surfaces formed out of the valley-like surfaces of an optical chassis. An electromagnetic drive mechanism for the lens holder includes the leg portions, magnets, and coils of the lens holder.

Growing community of inventors

Osaka, Japan

Ryotaro Nakagawa