Abstract: Provided is an encoder capable of achieving high position resolution without being finely divided, and capable of detecting a rotation angle or the like with high sensitivity. The encoder includes: rotary plate having a plurality of reflection structures repeatedly formed and code including light reflector; irradiator that irradiates the plurality of reflection structures with light; and light receiver that receives light reflected by the plurality of reflection structures. Each of the plurality of reflection structures has a surface in a convex shape, and each of the plurality of reflection structures has a width that is an integral multiple of a width of light reflector.

Abstract: Provided is an encoder capable of achieving high position resolution without being finely divided, and capable of detecting a rotation angle or the like with high sensitivity. The encoder includes: rotary plate (2) having a plurality of reflection structures (10) repeatedly formed and code (20) including light reflector (21); irradiator (4) that irradiates the plurality of reflection structures (10) with light; and light receiver (5) that receives light reflected by the plurality of reflection structures (10). Each of the plurality of reflection structures (10) has a surface in a convex shape, and each of the plurality of reflection structures (10) has a width that is an integral multiple of a width of light reflector (21).

Abstract: An advantage of the present invention is that it provides an optical pickup device including a first condensing member that condenses light from a first light source; a second condensing member that condenses light from a second light source; a holder that has the first and second condensing members attached thereto; a plurality of tracking coils that drive the holder in a tracking direction of an optical disk; and a plurality of focus coils that drive the holder in a focus direction of an optical disk. The plurality of focus coils are disposed in the holder such that virtual center axes for winding coil are set to be substantially perpendicular to the optical axes of the first and second condensing members, and are disposed in four direction such that the region in which the first and second condensing members are attached is surrounded in a rectangular shape.

Abstract: An advantage of the present invention is that it provides an optical pickup device including a first condensing member that condenses light from a first light source; a second condensing member that condenses light from a second light source; a holder that has the first and second condensing members attached thereto; a plurality of tracking coils that drive the holder in a tracking direction of an optical disk; and a plurality of focus coils that drive the holder in a focus direction of an optical disk. The plurality of focus coils are disposed in the holder such that virtual center axes for winding coil are set to be substantially perpendicular to the optical axes of the first and second condensing members, and are disposed in four direction such that the region in which the first and second condensing members are attached is surrounded in a rectangular shape.

Abstract: The present invention provides an optical pickup device comprising a light condensing means for condensing light emergent from a light source to an optical disk, a light condensing holder on which the light condensing means is mounted, a suspension holder for elastically supporting the light condensing holder, a focus coil mounted on the light condensing holder, a tracking coil mounted on the light condensing holder, and a magnetic field impression means for impressing a magnetic field upon the focus coil and the tracking coil, wherein the tracking coil is composed of a first to a third tracking coil portion combined with each other.

Abstract: In the case of a disk with a high NA which enables high-density recording, since the coma aberration increases as the numerical aperture, NA, increases, a disk protective layer needs to be thin very much, and a damage or scratch imparted to a surface of the disk affects largely the record and reproduction of data. An object of the invention is to reduce the generation of damage to a storage disk due to a collision between a lens holder or an objective lens and the storage disk. With a view to attaining the object, according to the invention, a longitudinal direction of a protector 11 provided on a holder is made substantially parallel to a straight line which connects the rotational center of a motor with the center of an objective member.

Abstract: An actuator has a moving portion including an objective lens, an objective lens holding cylinder, a focus coil, and a tracking coil, a first magnetic circuit for driving the focus coil, a second magnetic circuit for driving the tracking coil, and an elastic member for supporting the moving portion. The first magnetic circuit has a pair of focus coils and a pair of focus magnets disposed symmetrically about the objective lens and the second magnetic circuit has a pair of tracking coils and a pair of tracking magnets disposed symmetrically about the objective lens. Each of the pair of focus magnets in the first magnetic circuit and the pair of tracking magnets in the second magnetic circuit is constituted of divided magnets formed of a plurality of magnets joined together.

Abstract: An optical pickup device, comprises a first light source emitting light with a short wavelength; a second light source emitting s light with a wavelength longer than that of the first light source; an optical member guiding the light from the first light source and the light from the second light source on almost the same optical path; a focusing member focusing the light from the optical member; a movable lens provided between the optical member and the focusing lens; and a drive member driving the movable lens, wherein a position of the lens when at least one of recording and reproducing of information is carried out on a medium using the light from the first light source is made different from a position of the lens when at least one of the recording and reproducing of information is carried out on the medium using the light from the second light source.

Abstract: The present invention provides an optical pickup device comprising a light condensing means for condensing light emergent from a light source to an optical disk, a light condensing holder on which the light condensing means is mounted, a suspension holder for elastically supporting the light condensing holder, a focus coil mounted on the light condensing holder, a tracking coil mounted on the light condensing holder, and a magnetic field impression means for impressing a magnetic field upon the focus coil and the tracking coil, wherein the tracking coil is composed of a first to a third tracking coil portion combined with each other.

Abstract: Provided are a thin optical pick-up apparatus which can record and reproduce data to and from both high recording density disc and low recording density disc, and a thin optical disc unit using this optical pick-up apparatus. The optical pick-up apparatus comprises a short wave LDA 11, a long wave LDAB 12, a beam splitter 41, a riser prism 23 for turning an optical axis into an optical axis perpendicular to the optical disc, a composite filter 33 being integrally incorporated with the objective lens 32 while a surface of the composite filter 33 is opposed to an oblique surface of the riser prism 23 in parallel with each other.

Abstract: An actuator comprising: a moving portion including an objective lens, an objective lens holding cylinder, a focus coil, and a tracking coil; a first magnetic circuit for driving the focus coil; a second magnetic circuit for driving the tracking coil; and an elastic member for supporting the moving portion. The first magnetic circuit has a pair of focus coils and a pair of focus magnets disposed symmetrically about the objective lens and the second magnetic circuit has a pair of tracking coils and a pair of tracking magnets disposed symmetrically about the objective lens. Each of the pair of focus magnets in the first magnetic circuit and the pair of tracking magnets in the second magnetic circuit is constituted of divided magnets formed of a plurality of magnets joined together.

Abstract: An optical pickup apparatus suited for reducing the size and thickness and capable of performing a tilt control of an objective lens with ease, and an optical disk apparatus.