Abstract: A first phase structure corrects at least one of a spherical aberration due to a difference between a protective substrate thickness t1 and a protective substrate thickness t2 and a spherical aberration due to a difference between a first wavelength ?1 and a second wavelength ?2, and a second phase structure corrects at least one of a spherical aberration generated when the first wavelength ?1 is changed in a range of ±10 nm, a best image point movement generated when the first wavelength ?1 is changed in a range of ±10 nm, and a spherical aberration generated when environmental temperature is changed.

Abstract: A hybrid objective lens has a refractive lens and a diffractive optical element constructed by plural coaxial ring-shaped zones on at least one optical surface thereof. When n1, n2 and n3 each is a diffraction order of a diffracted ray having a maximum light amount among diffracted rays of each of first, second and third light flux having wavelength ?1, ?2 and ?3 when respective light flux comes to be incident into the diffractive structure respectively, the following formulas are satisfied: |n1|>|n2|, and |n1|>|n3|, and the hybrid objective lens converges a n1-th, n2-th and n3-th order diffracted ray of the first, second and third light flux onto an information recording plane of each of the first, second ant third optical information recording medium respectively so as to form an appropriate wavefront within respective prescribed necessary image side numerical apertures.

Abstract: A light source unit relating to the present invention includes a light source element; an optical-waveguide-formed element in which an optical waveguide is formed; a prism for turning back a light flux emitted from the light source and guiding the light flux toward an incident end of the optical waveguide; and a coupling optical system formed on the prism or provided as a separated body from the prism, for coupling the light flux emitted from the light source onto the optical waveguide.

Abstract: An optical pickup apparatus comprises first, second and third light sources to emit light fluxes of wavelength ?1, ?2 and ?3 for conducting recording and/or reproducing information for first, second and third optical information recording mediums having respective protective substrates of thickness t1, t2 and t3 and a diffractive optical element located on a common optical path for the first, second and third light sources. A converged-light spot is formed on the first optical information recording medium with m-th order diffracted-light ray of the wavelength ?1, on the second optical information recording medium with n-th order diffracted-light ray of the wavelength ?2, and on the third optical information recording medium with k-th order diffracted-light ray of the wavelength ?3 generated by the diffractive optical element respectively, wherein one of m, n and k is different from one of other two numbers.

Abstract: A method of producing a lens that includes shifting a first die relative to a second die, and pressing an optical material shaped in a preliminary form between the first die and the second die so as to form a lens having a configuration corresponding to a hollow portion formed by the first die and the second die while shifting the first die relative to the second die. The produced lens includes an effective optical surface configured to converge a light flux. The effective optical surface includes a light entrance side, a light exit side, and an optical axis. The effective optical surface is a convex surface shaped such that when a maximum normal line angle is defined as an angle formed between the optical axis and a normal line at the outermost circumference of the effective optical surface, the maximum normal angle is 60° to 90°.

Abstract: A light flux from the first light source forms a converged spot on first optical information recording medium by only a refraction action of the aspheric surface, or by a combination of the refraction action and an optical action given by at least one of the first phase structure and the second phase structure, a light flux from the second light source forms a converged spot on second optical recording medium by a combination of a refraction action of the aspheric surface and an optical action given by at least one of the first phase structure and the second phase structure, and a light flux from the third light source forms a converged spot on third optical recording medium by a combination of a refraction action of the aspheric surface and an optical action given by at least one of the first phase structure and the second phase structure.

Abstract: The lens unit for the optical pick-up apparatus has: the objective lens by which the projecting light from the light source is condensed on the information recording surface of the optical information recording medium; the phase control element which is arranged on the light source side to the objective lens, and which controls the phase of the projecting light from the light source; and the supporting member holding the objective lens and the phase control element; and the phase control element is held under the condition that its optical axis is inclined by a predetermined angle to the optical axis of the objective lens, and the intersection at which the optical axis of the phase control element crosses the optical surface having the phase structure is arranged on the optical path passing through the central point which passes the optical axis of the objective lens.

Abstract: An objective optical system according to the present invention is provided for use in an optical pickup apparatus for recording or reproducing information on an information recording surface of a first optical information recording medium using a first light flux emitted from a first light source. The objective optical system is provided with: a first lens with a positive refractive power including plastic; a second lens with a positive refractive power including plastic; and a first phase structure. A wavefront aberration change amount of the objective optical system when a wavelength of the first light flux changes, and a wavefront aberration change amount of the objective optical system when an ambient temperature of the objective optical system satisfy the predefined condition.

Abstract: An optical pickup apparatus for information recording and/or reproduction on different optical information recording media with compatibility among these media, the optical surface of a first objective lens and the optical surface of a second objective lens are formed only of a refractive surface. The second objective lens is used in common for the first light flux with a wavelength of ?1 and the second light flux with a wavelength of ?2, but in the case where the protective substrate t2 of the second optical information recording medium and the protective substrate t3 of the third optical information recording medium are the same, it is not necessary to take the difference in thickness of the protective substrate into consideration. Chromatic aberration based on the difference in wavelength between the first light flux and the second light flux can be corrected by displacing the second coupling lens.

Abstract: A light flux from the first light source forms a converged spot on first optical information recording medium by only a refraction action of the aspheric surface, or by a combination of the refraction action and an optical action given by at least one of the first phase structure and the second phase structure, a light flux from the second light source forms a converged spot on second optical recording medium by a combination of a refraction action of the aspheric surface and an optical action given by at least one of the first phase structure and the second phase structure, and a light flux from the third light source forms a converged spot on third optical recording medium by a combination of a refraction action of the aspheric surface and an optical action given by at least one of the first phase structure and the second phase structure.

Abstract: An objective lens unit for use in an optical pickup device, includes: a first lens section; a first flange section positioned peripheral of the first lens section; and a support section which supports a second objective lens having a second lens section provided in parallel to the first lens section with an optical axis different from that of the first lens section, wherein the first lens section, the first flange section and the support section are integrally formed.

Abstract: An objective lens system for an optical pickup apparatus, includes in order from an object side: a first lens group having negative paraxial power P1 (mm?1); and a second lens group having positive paraxial power P2 (mm?1) for converging a light flux emitted from the first lens group on an information recording surface of an optical information recording medium.

Abstract: A structure according to the present invention is an optical pickup apparatus including a first light source, a second light source, a third light source, a first objective optical system, a second objective optical system, an incidence optical system for emitting the first to third light fluxes into the first objective optical system or the second objective optical system, and an optical detector. The optical pickup apparatus converges a light flux emitted from the first light source onto an information recording surface of a first optical information recording medium or a second optical information recording medium, by using the first objective optical system.

Abstract: An objective lens system for an optical pickup apparatus, includes in order from an object side: a first lens group having negative paraxial power P1 (mm?1); and a second lens group having positive paraxial power P2 (mm?1) for converging a light flux emitted from the first lens group on an information recording surface of an optical information recording medium.

Abstract: An optical pickup apparatus has a semiconductor laser source which emits a laser beam in a wavelength band of 405 nm having an elliptic light intensity distribution; a beam shaping element which shapes the light intensity distribution of the laser beam; a polarizing beam splitter having a polarized light separation film in contact with the air and reflecting the laser beam shaped by the beam shaping element on the polarized light separation film; and an objective lens which focuses the laser beam reflected on the polarized light separation film onto an optical information recording medium.

Abstract: An optical pickup apparatus comprises first, second and third light sources to emit light fluxes of wavelength ?1, ?2 and ?3 for conducting recording and/or reproducing information for first, second and third optical information recording mediums having respective protective substrates of thickness t1, t2 and t3 and a diffractive optical element located on a common optical path for the first, second and third light sources. A converged-light spot is formed on the first optical information recording medium with m-th order diffracted-light ray of the wavelength ?1, on the second optical information recording medium with n-th order diffracted-light ray of the wavelength ?2, and on the third optical information recording medium with k-th order diffracted-light ray of the wavelength ?3 generated by the diffractive optical element respectively, wherein one of m, n and k is different from one of other two numbers.

Abstract: In order to provide an optical pickup apparatus that has a relatively simple configuration and that can carry out recording and/or reproduction of information in a s compatible manner for different optical information storage medium, the optical surface of the first objective lens OBJ1 is formed only by a refracting surface, and hence it is possible to form it at a low cost even if it is made of glass. In addition, said first objective lens OBJ1 can be designed by optimizing it for the first light flux with the wavelength ?1 and the protective substrate t1 of said first optical disk OD1.

Abstract: An optical pickup apparatus for information recording and/or reproduction on different optical information recording media with compatibility among these media, the optical surface of a first objective lens and the optical surface of a second objective lens are formed only of a refractive surface. The second objective lens is used in common for the first light flux with a wavelength of ?1 and the second light flux with a wavelength of ?2, but in the case where the protective substrate t2 of the second optical information recording medium and the protective substrate t3 of the third optical information recording medium are the same, it is not necessary to take the difference in thickness of the protective substrate into consideration. Chromatic aberration based on the difference in wavelength between the first light flux and the second light flux can be corrected by displacing the second coupling lens.

Abstract: An objective lens unit, includes: an objective lens for irradiating and converging laser light on an optical disc as an a light information recording medium; and a lens frame for retaining the objective lens, wherein the lens frame is structured so that at least a portion closer to a rotation center of the optical disc is offset to an inner side of the lens frame with regards to a virtual edge section closer to the rotation center of the optical disc, wherein the virtual edge section is in a nodal line of a virtual plane that includes an end face which is closest to the optical disc in the lens frame and the objective lens, and that is perpendicular to an optical axis and a virtual rotation curved surface that is obtained when a virtual straight line passing a portion which is farthest from the optical axis in the lens frame and the objective lens, in parallel with the optical axis, is rotated around the optical axis as a center axis.

Abstract: An optical system for use in an optical pickup apparatus comprises a first optical surface having a superposition type diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each ring-shaped zone is composed of a plurality of stepped sections stepwise, and a second optical surface having a diffractive structure including a plurality of ring-shaped zones which are formed concentrically around an optical axis, wherein each of the plurality of ring-shaped zones are divided by a stepped section to generate a diffractive light ray of diffractive order whose absolute value is not small than 1 for the light flux.