Abstract: In an optical pickup device, a flexible substrate (FPC) (2) and an auxiliary board (4) are fixed to an optical unit (5) with screws (11) before fixing an optical detector (1) to the FPC (2). After that, the optical detector (1) is pressed to the FPC (2) by probes (12), to bring lead portions (1a) into contact with conductor portions (2a). The optical detector 1 is singly moved by the probes (12) in that state, to perform position adjustment of the optical detector (1). Since the friction between the optical detector (1) alone and the FPC (2) is small, the position adjustment can be performed with high accuracy. Further, since the lead portions (1a) and the conductor portions (2a) are in contact with each other, it is possible to perform the position adjustment while observing an electrical signal outputted from the optical detector (1) through the FPC (2).

Abstract: An optical disc on which information can be recorded by recording light has a first recording layer (102) and a second recording layer (103) disposed behind the first recording layer as viewed by the recording light; the first recording layer and the second recording layer have respective power adjustment areas (P1, P2) that are used to adjust the power of the recording light to the optimal recording power at the time of recording of information on each recording layer; a prewrite area (PW) is provided in correspondence to the power adjustment area (P2) used for optimal power adjustment in the second recording layer and restricted areas (A1, A2) on both sides of that power adjustment area (P2). The restricted areas (A1, A2) allow for the diameter of the recording light beam and for lamination misalignment. This configuration enables stable test recording to be carried out in a short time on an optical disc having multiple recording layers.

Abstract: An optical actuator according to this invention includes a focusing lens for focusing a laser beam on a information disk, a lens holder for holding the focusing lens, a focusing coil for driving the focusing lens in an axial direction of the laser beam, a tracking coil for driving the focusing lens in a radial direction of the information disk, a tilting coil for pivotally rotating the focusing lens on an axis along the tangential direction of the disk and a pair of supporting members each disposed on each opposing sides of the lens holder. Each of the supporting members having at least three fixing elements disposed in an approximately circular arc, and a plurality of linear elastic members are connected to each of the fixing elements.

Abstract: A light wavefront measuring apparatus (2, 2a, 42) includes a separating element (7a, 47a) for separating a flux of light which exits from an optical head (1, 31) into a first beam and a second beam, a first interference fringe display section (21, 21a) for displaying interference fringes formed from the first beam, a Dove prism (13, 53) for rotating a wavefront of the second beam around its optical axis (AX2), and a second interference fringe display section (22, 22a) for displaying interference fringes formed from the second beam which passed through it. In adjustment of the light source device, position of a collimator (5) in the optical head (1, 31) is adjusted in optical axis direction so as to approximate the interference fringe patterns displayed in the interference fringe display sections (21, 22, 21a, 22a) each other.

Abstract: A write strategy for use in recording is determined from recommended write strategy parameters recorded on an optical disk (160) and the characteristics of the optical recording device used in recording; a recommended asymmetry value is determined from the difference between the numerical aperture NA1 of the objective lens, which is a recording condition of the recommended asymmetry value recorded on the optical disk (160) and the numerical aperture NA2 of the objective lens (150) of the optical recording device used in recording, and recording is carried out on the optical disk (160) according to the write strategy and asymmetry value thus determined. Optimal recording can be carried out even on an optical disk for which the optimal write strategy information has not been determined in advance, without the need to store write strategy information suitable for each and every optical disk.

Abstract: On an optical disk in a recording and/or playback apparatus, the position at which the thickness error of a light transmission layer is in the optical axis of an objective lens 11, and the position at which the recording/playback of information is performed is in the optical axis of a two-group objective lens 20, so that they are spaced apart from each other, making it impossible to accurately detect the thickness error at the position where the recording/playback of information is performed. Further, to chronologically compensate for the space between them, an excess circuit is required. In view of this, a first reflection light 107a reflected by a medium surface 106a of the optical disk is received to detect the focal error with respect to the medium surface, and a second reflection light 107b reflected by the surface of a light transmission layer 106b formed on the medium surface 106a to detect the focal error with respect to the surface of the light transmission layer 106b.

Abstract: Tracking coils are fixed on side surfaces of a lens holder and a magnetic substance of axisymmetric shape is fixed on a lower surface of the lens holder, being sandwiched by a focusing coil. Moreover, end portions of the magnetic substance are opposed to respective N-pole surfaces of permanent magnets serving as a focusing driving device and a tracking driving device together with the above coils. As a result, a neutral position holding system for an objective lens can be formed of these permanent magnets and the magnetic substance.

Abstract: An optical actuator according to this invention includes a focusing lens for focusing a laser beam on a information disk, a lens holder for holding the focusing lens, a focusing coil for driving the focusing lens in an axial direction of the laser beam, a tracking coil for driving the focusing lens in a radial direction of the information disk, a tilting coil for pivotally rotating the focusing lens on an axis along the tangential direction of the disk and a pair of supporting members each disposed on each opposing sides of the lens holder. Each of the supporting members having at least three fixing elements disposed in an approximately circular arc, and a plurality of linear elastic members are connected to each of the fixing elements.

Abstract: An objective lens (1) for focusing light on an optical recording medium (not shown) and irradiating the same with the focused light is held on a lens holder (2). A support member (10) is provided on a base member (9) as a foundation of a device for driving optical system. The lens holder (2) is supported on the support member (10). Six linear elastic bodies (7a through 7f) of the same length are cylindrically shaped. The lens holder (2) is supported on the support member (10) by the linear elastic bodies (7a through 7f). A center of a circle formed by the ends of the linear elastic bodies (7a through 7f) is an axis of point symmetry thereof. Distances between adjacent ones of the ends of the linear elastic bodies (7a through 7f) are all the same.

Abstract: Feedthrough apparatus has a metal housing with an opening therein and a base having a surface at the opening. A ceramic feedthrough extends through the opening in the housing and forms an interface therewith, and is brazed to the housing at the interface. The surface of the base extends at least to the feedthrough and has a cut-out area or opening therein adjacent the feedthrough in order to minimize the surface area contact at the interface between the ceramic feedthrough and the metal housing. The opening in the base may have edges which extend from sidewalls of the feedthrough under the feedthrough by small distances, in order to form a small ledge beneath the outer periphery of the feedthrough. Alternatively, the opening in the base may be approximately equal in size to the feedthrough so as to have edges which engage sidewalls of the feedthrough.

Abstract: An objective lens (1) for focusing light on an optical recording medium (not shown) and irradiating the same with the focused light is held on a lens holder (2). A support member (10) is provided on a base member (9) as a foundation of a device for driving optical system. The lens holder (2) is supported on the support member (10). Six linear elastic bodies (7a through 7f) of the same length are cylindrically shaped. The lens holder (2) is supported on the support member (10) by the linear elastic bodies (7a through 7f). A center of a circle formed by the ends of the linear elastic bodies (7a through 7f) is an axis of point symmetry thereof. Distances between adjacent ones of the ends of the linear elastic bodies (7a through 7f) are all the same.

Abstract: Tracking coils are fixed on side surfaces of a lens holder and a magnetic substance of axisymmetric shape is fixed on a lower surface of the lens holder, being sandwiched by a focusing coil. Moreover, end portions of the magnetic substance are opposed to respective N-pole surfaces of permanent magnets serving as a focusing driving device and a tracking driving device together with the above coils. As a result, a neutral position holding system for an objective lens can be formed of these permanent magnets and the magnetic substance.

Abstract: In an optical pickup device, a flexible substrate (FPC) (2) and an auxiliary board (4) are fixed to an optical unit (5) with screws (11) before fixing an optical detector (1) to the FPC (2). After that, the optical detector (1) is pressed to the FPC (2) by probes (12), to bring lead portions (1a) into contact with conductor portions (2a). The optical detector 1 is singly moved by the probes (12) in that state, to perform position adjustment of the optical detector (1). Since the friction between the optical detector (1) alone and the FPC (2) is small, the position adjustment can be performed with high accuracy. Further, since the lead portions (1a) and the conductor portions (2a) are in contact with each other, it is possible to perform the position adjustment while observing an electrical signal outputted from the optical detector (1) through the FPC (2).

Abstract: Feedthrough apparatus has a metal housing with an opening therein and a base having a surface at the opening. A ceramic feedthrough extends through the opening in the housing and forms an interface therewith, and is brazed to the housing at the interface. The surface of the base extends at least to the feedthrough and has a cut-out area or opening therein adjacent the feedthrough in order to minimize the surface area contact at the interface between the ceramic feedthrough and the metal housing. The opening in the base may have edges which extend from sidewalls of the feedthrough under the feedthrough by small distances, in order to form a small ledge beneath the outer periphery of the feedthrough. Alternatively, the opening in the base may be approximately equal in size to the feedthrough so as to have edges which engage sidewalls of the feedthrough.

Abstract: A light source (1) is composed of a single element having a light emitting point (2S) emitting a light (3S) and a light emitting point (2L) emitting a light (3L) at a longer wavelength than the light (3S), the light emitting point (2S) and the light emitting point (2L) being formed monolithically. In the direction parallel to the optical axis of a collimator lens (6), the light emitting point (2S) is placed closer, than the light emitting point (2L), to the collimator lens (6) and is placed on the side of the inclined plane (7a) of the beam shaping prism (7). The incidence angles of the light (3S) and the light (3L) to the inclined plane (7a) are set so that the incidence angle of the light (3S) is larger than that of the light (3L) and so that the lights (3S) and (3L) exit from the inclined plane (7a) at equal exit angles. The collimator lens (6), the beam shaping prism (7), etc. have refractive indexes which become larger as the wavelength of incident light becomes shorter.

Abstract: A lens holder (101) holds an objective lens (4) and a support shaft (103) is inserted in a bearing hole (101a) in the lens holder (101). Light that is emitted from a light source and reflected by an information recording medium enters two light receiving parts, which output currents (I21a, I21b) responsive to the amounts of light received. A controller (109) applies a current (196) based on the difference between the currents (I21a, I21b) to coils (116a) in an inclination drive unit (106). By interaction between the coils (116a) and magnets (116b), the lens holder (101) is turned on a first axis (I) while the light source and other components are secured. Fluids provided in the bearing hole (101a) further improve the vibration-resisting properties.

Abstract: On an optical disk in a recording and/or playback apparatus, the position at which the thickness error of a light transmission layer is in the optical axis of an objective lens 11, and the position at which the recording/playback of information is performed is in the optical axis of a two-group objective lens 20, so that they are spaced apart from each other, making it impossible to accurately detect the thickness error at the position where the recording/playback of information is performed. Further, to chronologically compensate for the space between them, an excess circuit is required. In view of this, a first reflection light 107a reflected by a medium surface 106a of the optical disk is received to detect the focal error with respect to the medium surface, and a second reflection light 107b reflected by the surface of a light transmission layer 106b formed on the medium surface 106a to detect the focal error with respect to the surface of the light transmission layer 106b.

Abstract: A light source (1) is composed of a single element having a light emitting point (2S) emitting a light (3S) and a light emitting point (2L) emitting a light (3L) at a longer wavelength than the light (3S), the light emitting point (2S) and the light emitting point (2L) being formed monolithically. In the direction parallel to the optical axis of a collimator lens (6), the light emitting point (2S) is placed closer, than the light emitting point (2L), to the collimator lens (6) and is placed on the side of the inclined plane (7a) of the beam shaping prism (7). The incidence angles of the light (3S) and the light (3L) to the inclined plane (7a) are set so that the incidence angle of the light (3S) is larger than that of the light (3L) and so that the lights (3S) and (3L) exit from the inclined plane (7a) at equal exit angles. The collimator lens (6), the beam shaping prism (7), etc. have refractive indexes which become larger as the wavelength of incident light becomes shorter.

Abstract: The reference character 5 denotes a supporting shaft holding base, which holds the lower end of a supporting shaft 103 coated with fluororesin with a small frictional coefficient. The reference characters 107a and 107b are tracking magnets bipolar-magnetized in the right and left direction, which are fixed to a fixing base 1 by bonding. The character 108 denotes a mirror for reflecting a light beam 2 incident from the front in the vertical upward direction. The character 6 denotes a lens holder formed of a plastic material, or the like, with light weight and high stiffness, which holds objective lenses 3 and 4 corresponding to a plurality of optical information recording media with different substrate thicknesses and different recording densities at positions eccentrically displaced by almost equal distances from the supporting shaft 103.

Abstract: In an optical disk device for recording or playing back information on or from an optical information recording medium having land parts forming information tracks and groove parts interposed between adjacent land parts, the land part is illuminated with a first light spot, and the groove part is illuminated a second light spot, a first focus error signal is produced in accordance with the reflected light beam of the first light spot, and a second focus error signal is produced in accordance with the reflected light beam of the second light spot, and focus control is performed in accordance with the first and second focus error signals. In another aspect of the invention, each of the light receiving sections of a photodetector used for receiving the reflected light has an array of tapered projections along in a region between main parts the light receiving sections, and the tapered projections of the light receiving sections are interdigitated with each other.