Abstract: An objective lens 8 consists of a single lens element. A light source side surface 8a is formed into a convex surface having a large curvature, and an optical recording medium side surface 8b has a small curvature. Also, the objective lens satisfies the following expressions (1) and (2) ?A/?B<5.0 ??(1) 7.69??A/?B+19.33×bf?/f??9.45 ??(2) where ?A denotes an effective diameter (mm) of the light source side surface of the objective lens 8, ?B denotes an effective diameter (mm) of the optical recording medium side surface of the objective lens 8, bf? denotes a back focal length (mm) of the objective lens 8, and f? denotes a focal length (mm) of the objective lens 8.

Abstract: An objective optical system is formed of a diffractive optical element with a diffractive surface formed on a virtual plane and an objective lens for focusing three light beams of three different wavelengths at three different numerical apertures onto desired positions of three different recording media with substrates that include different thicknesses, such as an AOD, a DVD, and a CD, that introduce different amounts of spherical aberration in the focused beams. The objective optical system provides compensating spherical aberrations to the three light beams, two of which are incident on the objective optical system as collimated beams and one of which is incident as a diverging beam. The objective optical system focuses second-order diffracted light of one wavelength and first-order diffracted light of the other two wavelengths. An optical pickup device includes the objective optical system, the recording media, and a light source that provides the three light beams.

Abstract: An objective lens consists of two lens elements of different materials that are cemented. The lens surfaces that are cemented includes a phase function so that the cemented surface forms a optical diffractive surface that enables the objective lens to focus incident light of three different wavelengths with different numerical apertures onto different optical recording media. Three conditions are satisfied so as to achieve optimum imaging. The optical diffractive surface is shaped so that the order of the diffracted light of the shortest wavelength ?1 having the largest diffracted intensity is zero and different from the order of the diffracted light of the second wavelength ?2 having the largest diffracted intensity, and the order of the diffracted light of the first wavelength ?1 having the largest diffracted intensity is also different from the order of the diffracted light of the third wavelength ?3 having the largest diffracted intensity.

Abstract: An objective optical system includes a diffractive optical element on the light source side of an objective lens for focusing incident light of three different wavelengths with two different numerical apertures onto three different optical recording media. The diffractive optical element is formed of two lens elements made of different materials that are cemented together at a diffractive surface. Three conditions are satisfied so as to achieve optimum imaging. The diffractive surface may be shaped so that the order of the diffracted light of the shortest wavelength ?2 having the largest diffracted intensity is different from the order of the diffracted light of the second wavelength ?2 having the largest diffracted intensity, and the order of the diffracted light of the first wavelength ?1 having the largest diffracted intensity is also different from the order of the diffracted light of the third wavelength ?3 having the largest diffracted intensity.

Abstract: A variable-power optical system includes, in order from an object side, first to fifth lens groups. The first and third lens groups are fixed at a time of varying magnification and at a time of focusing. The second, fourth and fifth lens groups are movable at the time of varying magnification. The first, third and fourth lens groups have positive refractive powers. The second and fifth lens groups have negative refractive powers. The fourth lens group has a focusing function. The following conditional expressions are satisfied. 0.4<fw/f1<0.8 0.5<|f2/fw|<0.8 where fw denotes a focal length of the whole system at an wide end, f1 denotes a focal length of the first lens group, and f2 denotes a focal length of the second lens group.

Abstract: A zoom lens is provided and includes: in order from an object side thereof, a first lens group having a negative refractive power, a stop; a second lens group having a positive refractive power; and a third lens group having a positive refractive power. The magnification of the zoom lens is varied from a wide angle end to a telephoto end by changing a space between the first lens group and the second lens group and a space between the second lens group and the third lens group. The first lens group includes: in order from an object side thereof, a negative lens having at least one aspherical surface and having a concave surface on an image side thereof; and a positive meniscus lens having a convex surface on the object side thereof. The zoom lens satisfies conditional expressions specified in the specification.

Abstract: A laser beam output from a semiconductor laser light source 1 is transmitted through a cover glass 2 in the optical axis Z direction, is incident on a molded lens 4 in a state of divergent rays, is converted into convergent rays by the molded lens 4, and is applied onto a recording face 5 of the optical recording medium. A diaphragm 3 is arranged. An area of each lens surface onto which a luminous flux of the laser beam restricted by the diaphragm 3 is applied corresponds to an effective area. The following expression (1) is satisfied: d1?d0?0.04 mm ??(1) where d0 denotes an effective aperture of one of the lens surfaces, and d1 denotes an outer diameter of the one of the lens surfaces.

Abstract: An optical recording media objective lens is disclosed for converging either of two working lights of a first wavelength or a second wavelength. The working light of the first wavelength is converged at a first numerical aperture onto the first optical recording medium and the working light of the second wavelength is converged at a second numerical aperture onto the second optical recording medium. An aperture adjusting zonal part is included on at least one of the objective lens surfaces for apparently eliminating light at the periphery of a light flux having a wavelength ?1 while maintaining light at the periphery of a light flux having a wavelength ?2, where ?1 is one of the first and second wavelengths and ?2 is the other wavelength. The aperture adjusting zonal part is formed so as to satisfy two conditions.

Abstract: An objective lens is formed as an objective lens element with a diffractive surface on one side. The objective lens focuses a collimated light beam of a first wavelength diffracted by the objective lens onto a first recording medium, a collimated light beam of a second wavelength diffracted by the objective lens onto a second recording medium, and a diverging light beam of a third wavelength diffracted by the objective lens onto a third recording medium. The three light beams are focused at three different working distances from the objective lens and the diffraction orders of the diffracted light of two of the light beams is the same. The objective lens satisfies certain conditions related to the shortest of the three different working distances, the focal length of the objective lens element at the shortest of the three wavelengths, and the thickness of the objective lens.

Abstract: A variable power optical system is provided and includes a positive first lens group, a negative second lens group, a positive fifth lens group, a positive third lens group, and a negative fourth lens group containing first to third sub lens groups, in order from the side of an object. The second lens group is moved, thereby performing variable power and the third lens group is moved, thereby correcting image surface variation caused by the variable power and performing focusing. The fourth lens group is fixed at the variable power time and the focusing time. To correct image blurring, only the second sub lens group is moved in a direction perpendicular to an optical axis. Accordingly, a sufficiently good image blurring correction function can be exerted and a simple and compact configuration as a whole can be implemented.

Abstract: An objective lens and an optical pickup device utilizing it are disclosed wherein the objective lens includes a specified aspheric surface profile having a discontinuity and a single specified diffraction optical surface so to provide a focusing effect which is usable with different optical recording media, such as a CD versus a DVD. By providing a single diffraction surface and an aspheric surface having a discontinuity, more freedom of design is achieved for the diffraction surface than would otherwise be possible. The objective lens according to the invention is designed so as to be both compact and inexpensive and enables recording/playback onto either type optical recording media using different wavelengths and different numerical apertures, depending on the recording medium used.

Abstract: A zoom lens includes a function of preventing blurring of an image due to movements, such as shaking of the zoom lens, by moving the second lens group, in order from the object side, orthogonally to the optical axis in order to correct for blurring of an image due to movements of the zoom lens. The zoom lens includes a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. The first and second lens groups move along the optical axis during zooming, as does the third lens group in all but one embodiment of the invention. The zoom lens satisfies certain conditions related to the configuration of the lens elements and lens groups of the zoom lens in order to prevent blurring and to provide a compact zoom lens having excellent correction of aberrations.

Abstract: The present invention includes a first plate (14) and a second plate (15) which perform a coarse adjustment of a cylinder mirror (245) by moving the cylinder mirror (245) linearly in the substantially vertical and parallel directions with respect to an appropriate plane surface of a reflective surface (RS) of the cylinder mirror (245), and the second plate (15), a second plate opening section (15b), a setscrew (24), and a hexagon shaft (25) which perform a fine adjustment in the position of the cylinder mirror (245) by moving linearly only in the substantially parallel direction after the coarse adjustment has been completed.

Abstract: A zoom optical system includes a function of preventing blurring of an image due to movements, such as shaking of the zoom optical system, by moving a lens element of the third lens group, in order from the object side, of four lens groups in a direction that is perpendicular to the optical axis in order to correct for movements of the zoom optical system that would otherwise create a blurred image. The second lens group from the object side has negative refractive power and the other three lens groups have positive refractive power. The second and fourth lens groups move along the optical axis during zooming. The zoom optical system satisfies certain conditions related to the configuration of the lens elements and lens groups of the zoom optical system in order to prevent blurring and to provide a compact zoom optical system having excellent correction of aberrations.

Abstract: An electrode is made by turning a harness such that the electrode has a predetermined are for detecting capacitance. A method of manufacturing of an electrode includes step so turning a wire, and shaping the electrode with the wire. The electrode has a predetermined area for detecting capacitance.

Abstract: A zoom optical system includes three lens groups, arranged as follows from the object side: a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. The first lens group includes, arranged as follows along the optical axis, a lens element having negative refractive power, a prism for bending the optical axis, and a lens element having positive refractive power. The second and third lens groups are movable along the optical axis for zooming with only the third lens group reversing its direction of movement along the optical axis during zooming from the wide-angle end to the telephoto end. The third lens group includes a stop, a cemented lens component, and at least one aspheric surface that may be made of plastic. The first lens group also includes at least one aspheric surface.

Abstract: An objective optical system for optical recording media and an optical pickup device using the objective optical system includes a holographic optical element that includes angularly-multiplexed holograms for correcting spherical aberration and/or coma aberration due to variations in substrate thicknesses of recording media and errors by tilting the holographic optical element out of the plane perpendicular to the optical axis by specified amounts. A control system determines the spherical aberration and/or coma using a control unit and outputs command signals for controlling the amount of tilt. The angularly-multiplexed holograms may change an input substantially collimated light beam to a divergent or convergent light beam except when the substrate of the optical recording media has a specified thickness. Additionally, the holographic optical element may include wavelength-multiplexed holograms to correct for chromatic aberration due to mode hopping of a semiconductor laser light source.

Abstract: A zoom optical system includes three lens groups, arranged as follows from the object side: a first lens group having positive refractive power, a second lens group having negative refractive power, and a third lens group having positive refractive power. The first lens group includes, arranged as follows along the optical axis, a lens element having negative refractive power, a prism for bending the optical axis, and a lens element having positive refractive power. The second and third lens groups are movable along the optical axis for zooming with only the third lens group reversing its direction of movement along the optical axis during zooming from the wide-angle end to the telephoto end. The third lens group includes a stop, a cemented lens component, and at least one aspheric surface that may be made of plastic. The first lens group also includes at least one aspheric surface.

Abstract: A zoom lens includes a function of preventing blurring of an image due to movements, such as shaking of the zoom lens, by moving the second lens group, in order from the object side, orthogonally to the optical axis in order to correct for blurring of an image due to movements of the zoom lens. The zoom lens includes a first lens group having negative refractive power, a second lens group having positive refractive power, and a third lens group having positive refractive power. The first and second lens groups move along the optical axis during zooming, as does the third lens group in all but one embodiment of the invention. The zoom lens satisfies certain conditions related to the configuration of the lens elements and lens groups of the zoom lens in order to prevent blurring and to provide a compact zoom lens having excellent correction of aberrations.

Abstract: A zoom optical system includes a function of preventing blurring of an image due to movements, such as shaking of the zoom optical system, by moving a lens element of the third lens group, in order from the object side, of four lens groups in a direction that is perpendicular to the optical axis in order to correct for movements of the zoom optical system that would otherwise create a blurred image. The second lens group from the object side has negative refractive power and the other three lens groups have positive refractive power. The second and fourth lens groups move along the optical axis during zooming. The zoom optical system satisfies certain conditions related to the configuration of the lens elements and lens groups of the zoom optical system in order to prevent blurring and to provide a compact zoom optical system having excellent correction of aberrations.