Funai Electric Company Ltd.

Teruaki Sogawa

Nobuyuki Kimura

Naoyuki Wakabayashi

Manabu Murayama

Takayuki Murakami

Hideki Kume

Noritaka Tanabe

Shingo Hamada

Fumiaki Mori

Masanori Takahashi

Hideaki Funakoshi

Ryotaro Nakagawa

Toshiharu Hibi

Toyoshi Nogami

Hiromasa Sasaoka

Katsuichi Inoue

Takashi Kasahara

An optical pickup includes a semiconductor laser, a beam splitter, a collimating lens, an objective lens, an aperture and a front monitor. The beam splitter splits a light beam emitted by the semiconductor laser into transmitted light and reflected light. The front monitor detects luminous energy of the transmitted light. The front monitor is disposed near an optical axis of the transmitted light so that the following is satisfied: 1&#x2266;(S&#xd7;L)/(s&#xd7;f)&#x2266;6.8. S is an area of an entrance pupil of the objective lens, f is an optical distance from an emission portion of the semiconductor laser to the collimating lens, s is an effective receiving area of the front monitor, and L is an optical distance from the emission portion of the semiconductor laser to the front monitor.

Optical pickup

A light-source holder used to hold a light source disposed in an optical pickup comprises: a holder main body portion; a through hole which penetrates the holder main body portion and in which a light source is fitted; a first hold potion that holds a first light source if the first light source is fitted in the through hole from a first side, one of first and second sides of the holder main body portion which are opposite to each other with respect to the holder main body portion; and a second hold portion that holds a second light source if the second light source is fitted in the through hole from a second side, one of the first and second sides of the holder main body portion which are opposite to each other with respect to the holder main body portion.

Light-source holder and optical pickup having 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 a processing section, allowable gain-value range defining unitmeasures a gain value k corresponding to a level ratio between an MPP signal and an SPP signal generated by a tracking error signal generating circuitto define an allowable range of the gain value, and eccentricity measuring unitmeasures an eccentricity of an optical disk. If the eccentricity is determined to be greater than or equal to a predetermined value by eccentricity determining unit, gain-value defining unitselects a minimum value of the gain value k to define the minimum value as a gain value k of an amplifier. On the other hand, if the eccentricity is determined to be less than the predetermined value, the gain-value defining unitselects a central value of the gain value k to define the central value as the gain value k of the amplifier

Optical disk recording/reproducing apparatus

An optical pickup includes a radiating plate made to abut against a rear surface of a laser diode by positioning an engaging hole provided penetratingly in a central portion of the radiating plate concentrically with the laser diode. Slits are formed in the radiating plate to form a pair of tongues in the manner of point symmetry about an axis of the engaging hole. Screw insertion portions formed in the respective tongues are communicates with the slits. As screws are passed through the screw inserting portions and are screwed in, the radiating plate is secured to the base. When the screws are screwed in, the axis is positioned on a phantom line connecting points of application of force generated at proximal end portions of the tongues. Distances from the axis to the respective points of application of force are set to be substantially identical.

An optical pickup has a base having a screw hole, a holder attached to the base, a laser diode held by the holder, a leaf spring, and an adjusting screw. The holder is formed of a substantially rectangular metal plate having short and long sides and is formed with a laser hole for fitting the laser diode through a center thereof. An angular fulcrum is formed at the center of a back surface of the holder along a direction parallel to the short side. The fulcrum is brought into abutment with the base via the leaf spring and one end of the holder is urged toward the base by the leaf spring. The holder is temporarily secured to the base by screwing the adjusting screw through an insertion hole formed at the other end of the holder into the screw hole of the base.

An optical pickup has a laser mounting surface formed around an opening portion of a laser hole while a notch groove ranging from the laser mounting surface to an operating hole is formed in a laser hole side wall portion. A fitting piece removably fitted into the notch groove is provided integrally with a metal holder which is provided for supporting a photodiode and which is locked in the laser mounting surface. The operating hole is defined between a forward end of the fitting piece and an inner end of the notch groove. A laser diode is fitted into a lock hole of the holder coaxial with the laser hole while a radiator plate is attached to the outer surface of the holder. Thus, the laser diode is held between the holder and the radiator plate.

In a biaxial actuator for an optical pickup, rising pieces are bend-formed on a base member on which a lens holder having an objective lens is placed in such a way as to be able to displace in a focusing direction and in a tracking direction. The strength of the base member is increased by setting the width of the bend-formed portion at the root of each of the rising pieces in such a way as to be larger than the width of any other part of the associated rising piece. Preferably, the shape of a side elevation section of each of the rising pieces is set to be a trapezoid.

Biaxial actuator for optical pickup and optical pickup

In an optical pickup device with a defocus adjustor used for adjusting a position of a photo-sensor against an optical system, the photo-sensor is mounted on a flexible printed circuit board, and the flexible printed circuit board is fixed on a plate spring. A first end of the plate spring with the flexible printed circuit board is fixed on a fixing face of a holder. Since the fixing face of the holder is inclined and the plate spring is formed flat with no bending portion, the plate spring is warped for generating a stress when the second end of the plate spring is fixed on the holder by an adjusting screw. The position of a photo-sensing face of the photo-sensor can be fine adjusted by tightening or loosening the adjusting screw.

Optical pickup device with defocus adjuster

An optical pickup has a pair of left and right leg portions formed integrally at both side edge portions of a rear end portion of a resilient plate. The leg portions extend forwardly along a horizontal longitudinal direction. A pair of fixing holes are penetratingly provided in the respective leg portions on a transverse phantom line passing through a central portion of the resilient plate and extending in a horizontal transverse direction and at positions spaced apart an equal interval from a longitudinal phantom line passing through the central portion of the resilient plate and extending in the horizontal longitudinal direction. A pair of fixing screws are screwed into a pair of threaded holes in a mounting surface of a base through the fixing holes, thereby fixing the leg portions to the mounting surface.

An optical pickup has a support pedestal integrally formed at a rear end portion of a mounting surface of a base. A pair of left and right leg portions extend forwardly from both side edge portions of a rear end portion of a resilient plate. A fixing hole is penetratingly provided in each of the leg portions on a phantom line passing through a central axis of a photodiode and extending in a horizontal transverse direction. Each fixing screw is screwed into a threaded hole in the mounting surface through each fixing hole, so as to press the rear end portion of the resilient plate against the support pedestal.

This chucking apparatusis an apparatus for holding a diskwhich has been placed on a turntableof a disk player, and includes a magnet, a chuck disk, a chuck arm, first engaging facesand second engaging faces. The chuck diskis arranged so as to be faced with the turntable, and adapted to hold the magnet. The chuck diskis a disc-like member which has a plurality of clawsformed around the magnetwhich has been held and projecting toward the turntable, and engaging partsprovided at distal end portionsof the plurality of clawsto be engaged with an outer circumference of the magnet. The chuck armholds the chuck diskrotatably. The first and the second engaging facesandrestrict the engaging partsof the clawsfrom deflecting in a direction away from the magnet.

Chucking apparatus of disk player

A disc rotating apparatus includes a turntable for placing thereon a disc such as CD, DVD. The disc is clamped by the turntable and the disc holding frame. The holding frame is formed, at its main body, with an annular groove. The annular groove is circumferentially partitioned by a plurality of partition walls to thereby provide a plurality of accommodating portions. Each of the accommodating portions accommodates therein one or two or more steel balls. Due to rotation of the turntable or disc, each steel ball is displaced within the accommodating portion, thereby correcting for an unbalanced state wherein a center of gravity of the disc is deviated from an axis of a rotary shaft of turntable.

Disc rotating apparatus with balance correcting balls

An attachment part of a mirror fixture is housed in a recess part of an optical system unit and edge-like end margins of a pair of opposed engagement piece parts of the attachment part are retained on a pair of opposed walls and of the recess part in a press state. An operational piece part is extended backward from each of the engagement piece parts and housed in an operational jib insertion recess-in part of the optical system unit. If the tip of an operational jig such as tweezers is inserted into the recess-in part and the operational piece parts are deformed inward, the engagement pieces parts also become deformed inward and the retention state with the walls is released.

Growing community of inventors

Osaka, Japan

Teruaki Sogawa