Abstract: A zoom optical system with a vibration correction function includes, from the object side, a first lens group having positive refractive power and that is stationary during zooming, a second lens group having negative refractive power and that moves along the optical axis during zooming, a third lens group having positive refractive power that includes a stop, and a fourth lens group having positive refractive power. Two of the second, third, and fourth lens groups move along the optical axis during zooming. A fifth lens group may be included. At least part of one of the third, fourth, or fifth lens groups that does not move along the optical axis during zooming is movable in a direction that intersects the optical axis in order to correct for blurring of an image due to vibration of the zoom optical system. An imaging device uses the zoom optical system.

Abstract: An objective optical system for focusing light from a light source onto optical recording media includes an objective lens formed of, arranged in order from the light source side along an optical axis, a plastic lens element having a diffractive surface on its light source side and a glass lens element having positive refractive power and an aspheric surface. The lens elements are joined to form a lens component. The objective optical system focuses incident light of three different wavelengths with two or three different numerical apertures onto three different optical recording media. Three conditions are satisfied so as to achieve optimum focusing onto three different recording media, such as a CD, a DVD, and a BD or an AOD.

Abstract: A three-group zoom lens includes, in order from the object side, first, second and third lens groups having negative, positive and positive refractive power, respectively. During zooming from the wide-angle end to the telephoto end, the second lens group moves monotonically toward the object side while moving closer to the first lens group and farther from the third lens group, and the first and third lens groups reverse directions to define curved paths. The third lens group is closer to the object side at the wide-angle end and moves toward the object side for close focusing. The focal lengths of the zoom lens and its lens groups, the zoom ratio, the length of the zoom lens, and the half-field angle at the wide-angle end satisfy certain conditions in order to achieve a zoom ratio of at least three with favorable correction of aberrations.

Abstract: An objective optical system focuses light from a light source onto at least two different types of optical recording media having different substrate thicknesses in order to record or reproduce information on the optical recording media by using a variable refractive power element and an objective lens. The variable refractive power element may be a liquid crystal element with concentric zones that serves as a transparent plate having no convergence effect when no voltage is applied when selecting an AOD, DVD, or CD and as a converging lens when a voltage is applied when selecting a BD. Alternately, the variable refractive power element may electrically vary the refractive index of a nanoparticle dispersion or at least one liquid of a two-liquid lens element. A diffractive optical element may be used to assist in focusing light to four recording media. An optical pickup device includes the objective optical system.

Abstract: An objective optical system for focusing light from a light source onto at least two different types of optical recording media having different substrate thicknesses in order to record or reproduce information on the optical recording media includes at least two lens groups arranged along an optical axis for focusing light of each one of two wavelengths that are the same or very nearly the same from the light source on a different one of the at least two different types of optical recording media, such as an AOD and a BD, having different substrate thicknesses. The separations of the two lens groups are different when light of each wavelength is used, and four different types of optical recording media with different substrate thicknesses may be used. An optical pickup device includes the objective optical system, the recording media, and a light source supplying the light of the two wavelengths.

Abstract: An objective optical system for focusing light from a light source onto optical recording media includes an aperture control filter with a diffractive optical function formed as a glass plate with an aperture control structure on one side and a diffractive optical structure, such as a plastic diffractive optical element adhered to the glass plate on the other side, and an objective lens. The objective optical system focuses three light beams of three different wavelengths at three different numerical apertures onto desired positions of three different recording media with substrates of different thicknesses, such as a BD (or 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 aberration to the three light beams while keeping constant the distance between the aperture control filter with a diffractive optical function and the objective lens.

Abstract: An objective optical system focuses light from a light source onto at least two different types of optical recording media having different substrate thicknesses in order to record or reproduce information onto the optical recording media by using a different light convergence or divergence effect based on a difference in the vibrational direction of the polarization of polarized incident light. This difference may be caused by passing the light through a uniaxial crystal, such as crystallized quartz, that has its optic axis arranged to use an extraordinary ray and an ordinary ray that are subject to different refractive indexes in an objective optical system even though the rays have the same wavelength. Diffractive optics may also be used to enable excellent focusing on more than two recording media. An optical pickup optical system and an optical pickup device using this optical pickup optical system include the objective optical system.

Abstract: An objective optical system is formed of a diffractive optical element with a diffractive surface formed on a planar ‘virtual surface’ (i.e., a surface that would be planar but for the diffractive structure) and an objective lens for focusing three collimated light beams of three different wavelengths at three different numerical apertures onto desired positions of three different recording media with substrates of 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 aberration to the three light beams while keeping equal the distance between the diffractive optical element and the objective lens, and 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 supplying the three light beams.

Abstract: A three-group zoom lens includes first, second, and third lens groups, of negative, positive, and positive or negative refractive power, respectively. The second lens group includes a stop and the third lens group moves for focusing. When zooming from the wide-angle end to the telephoto end, the first and second lens groups become closer together. The zoom lens preferably satisfies specified conditions that ensure compactness, ease of manufacture, and favorable correction of aberrations. The zoom lens includes aspheric lens elements with lens surfaces defined by an aspheric lens equation that: (a) includes at least one non-zero coefficient of an even power of Y, and at least one non-zero coefficient of an odd power of Y, where Y is the distance of a point on the aspheric lens surface from the optical axis, and/or (b) includes at least one non-zero coefficient of Yi, where i is even and 16 or greater.

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: 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 collimated 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 aberration to the three light beams by varying the distance between the diffractive optical element and the objective lens with the recording medium being used. 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 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: 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: A three-group zoom lens includes, in order from the object side, first, second and third lens groups having negative, positive and positive refractive power, respectively. During zooming from the wide-angle end to the telephoto end, the second lens group moves monotonically toward the object side while moving closer to the first lens group and farther from the third lens group, and the first and third lens groups reverse directions to define curved paths. The third lens group is closer to the object side at the wide-angle end and moves toward the object side for close focusing. The focal lengths of the zoom lens and its lens groups, the zoom ratio, the length of the zoom lens, and the half-field angle at the wide-angle end satisfy certain conditions in order to achieve a zoom ratio of at least three with favorable correction of aberrations.

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 may be shaped so that the order of the diffracted light of the shortest wavelength ?1 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: 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 &lgr;1 while maintaining light at the periphery of a light flux having a wavelength &lgr;2, where &lgr;1 is one of the first and second wavelengths and &lgr;2 is the other wavelength. The aperture adjusting zonal part is formed so as to satisfy two conditions.

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: 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: An aperture limiting element that has a wavelength selectivity is disclosed wherein an aperture that is an open space of a specified size formed in a substrate and, in an area outside the aperture and that surrounds the aperture, a light filter is provided wherein light of a specified wavelength &lgr;1 is transmitted straight through, and light of a wavelength &lgr;2 is prevented from passing straight through. Alternatively, the light filter may be provided with an inner first region that transmits light of first and second wavelengths &lgr;2 and &lgr;2, respectively, and does not transmit straight through light of a third wavelength &lgr;3, where &lgr;1<&lgr;2<&lgr;3; and in an area outside of the inner first region, there is constructed an outer second region that transmits light of the first wavelength &lgr;1, and does not transmit straight through light of the second and the third wavelengths &lgr;2 and &lgr;3.

Abstract: A three-group zoom lens includes, in order from the object side, a first lens group of negative refractive power, and second and third lens groups, each of positive refractive power. The first and second lens groups include negative and positive components and the third lens group is a single lens component. All but one lens component may be a single lens element. When zooming from the wide-angle end to the telephoto end, the first and second lens groups move closer together while the second lens group moves farther from the third lens group. The third lens group remains stationary during zooming but moves for focusing. The second lens group includes a diaphragm on its object side. Aspheric lens surfaces are disclosed. The zoom lens satisfies certain conditions for the focal lengths of the zoom lens and a component of the zoom lens, and for Abbe numbers of two lens elements.