Abstract: An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: |?SA1/?U|·|?U|+|?SA2/?T|·|?T|?0.07 ?rms where ? represents a wavelength of a light source, ?SA1/?U represents a change of a spherical aberration for an object-to-image distance change ?U (|?U|?0.5 mm) and ?SA2/?T represents a change of spherical aberration for a temperature change ?T (|?T|?30° C.), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface.

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: An objective lens for at least one of recording and reproducing for an optical information recording medium includes in the order from a light source side: a first lens group having negative refracting power, which is in a meniscus shape having a concave surface facing the light source side; a second lens group having positive refracting power; and a third lens group having positive refracting power, which is in a meniscus shape having a concave surface facing an image side.

Abstract: An objective optical element of an optical pickup apparatus has a magnification m1 satisfying the following formula for a light flux of the wavelength ?1:?1/7?m1??1/25 and |m1 |<|M1, where M1 is an optical system magnification from the first light source to the first optical information recording medium for a light flux of the wavelength ?1. The objective optical element comprises a common region and an exclusive region. The exclusive region includes an exclusive diffractive structure having a function to suppress an increase of spherical aberration due to a raise of atmospheric temperature. A light flux of a wavelength ?2. having passed through the exclusive diffractive structure intersects with the optical axis at a position different from the position of the converged light spot formed on the information recording plane of the second optical information recording medium.

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: An objective lens has a first meniscus-shape lens including a first object-side surface having a positive reflective power; and a second meniscus-shape lens having a positive reflective power. The first meniscus-shape lens and the second meniscus-shape are arranged in that order from an object side. The objective lens satisfies the following formulas: fF/f??1.1 LH1H2/f?0.5 fB/f?0.2 L/f?1.3 where f is an object-side focus length of the objective lens, fF is a front focus, fB is a back focus, LH1H2 is a length between an object-side principal point H1 and an image-side principal point H2, and L is a length on an optical axis of the objective lens between the first object-side surface and the second image-side surface.

Abstract: An optical pickup apparatus which conducts reproducing and/or recording information for a first optical information recording medium by using a light flux having a wavelength ?1 (350??1 (nm)?480) and a second optical information recording medium. The optical pickup apparatus comprises an output angle conversion element which is a fixedly arranged single lens which can convert an output angle of the first light flux and the second light flux. The optical detector equipped in the optical pickup apparatus can receive both of the first light flux and the second light flux. And, both optical surfaces of the output angle conversion element are refractive surfaces.

Abstract: An optical pick-up apparatus has a first light source, a second light source, and an optical system including an objective lens. An optical functional surface of the objective lens is divided into at least first and second concentric optical functional regions. The second functional region is provided with a diffractive structure to correct a spherical aberration of a converged light spot on an information recording plane to be regulated in a range where reproduction and/or recording information for a first optical information recording medium can be conducted when the refractive index of the optical element and the wavelength of the first light source vary due to a change of the working temperature of the optical system.

Abstract: An objective lens for use in an optical pickup apparatus has a diffractive optical surface. A first light flux having a first wavelength of ?1 is converged as a first number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto an information recording plane of the first optical information recording medium having a thinner protective substrate t1 by the diffractive optical surface and a second light flux having a second wavelength of ?2 (?1<?2) is converged as a second number diffraction order diffracted-ray other than the zero-th order diffracted-ray onto the information recording plane of the second optical information recording medium having a thicker protective substrate t2 (t1<t2) by the diffractive optical surface. The second number diffraction order is different from the first number diffraction order.

Abstract: An optical pickup apparatus includes: a first light source for emitting a first light flux; a second light source for emitting a second light flux; a third light source for emitting a third light flux; and an objective optical unit having a first optical path difference providing structure and a second optical path difference providing structure. Magnifications of the objective optical unit for the first-third light fluxes have almost same value. The first optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be one of under-correction and over-correction for all of the first light flux, the second light flux, and the third light flux. The second optical path difference providing structure provides a predefined optical path difference and changes a spherical aberration to be the other of under-correction and over-correction of the spherical aberration only for the second light flux.

Abstract: An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: |?SA1/?U|·|?U|+|?SA2/?T|·|?T|?0.07 ?rms where ? represents a wavelength of a light source, ?SA1/?U represents a change of a spherical aberration for an object-to-image distance change ?U (|?U|?0.5 mm) and ?SA2/?T represents a change of spherical aberration for a temperature change ?T (|?T|?30° C.), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface.

Abstract: An optical pickup apparatus conducts recording or reproducing information for an information recording plane of a first or second optical information recording medium and comprises a first light source and a second light source mounted on a same base board; a converging optical system; and a coupling lens. The converging optical system comprises an objective lens to converge a first or second light flux having passed through the coupling lens on a first or second optical information recording medium; and a diffractive structure to change a focal length in accordance with a wavelength of a light flux emitted from the first light source or the second light source.

Abstract: An objective lens of an optical pickup apparatus converges a divergent light flux onto an information recording surface. The following conditional formula is satisfied: |?SA1/?U|·|?U|+|?SA2/?T|·|?T|?0.07 ?rms where ? represents a wavelength of a light source, ?SA1/?U represents a change of a spherical aberration for an object-to-image distance change ?U (|?U|?0.5 mm) and ?SA2/?T represents a change of spherical aberration for a temperature change ?T (|?T|?30° C.), the object-to-image distance is a distance between the light source (a light emitting point) and the information recording surface.

Abstract: The present invention has a beam shaping element for converting the light source 11 into a light flux whose emitting angle is almost equal and for projecting it, and a generation amount of the astigmatism generated by the temperature change is suppressed by a linear expansion of the beam shaping element.

Abstract: An optical pick-up apparatus comprising: a first light source emitting a the first light flux; a second light source emitting a second light flux; a third light source emitting a third light flux; and an optical element, wherein the optical element has a first optical surface having a first area including an optical axis of the optical element, and a second area positioned outside the first area, the second area includes a light-shielding structure being capable of substantially shielding the third light flux and being capable of transmitting the first light flux and the second light flux.

Abstract: An optical pickup apparatus comprises a first, second and third light beam sources for emitting first light beams having wavelengths ?1, ?2 and ?3 (?1<?2<?3) for a first, second and third recording medium respectively having a first, a second and a third protective layers of thickness t1, t2 and t3, an objective optical lens for converging the first, the second and the third light beams onto respective recording surfaces of the first, second and the third recording media, a tracking device for moving the objective optical lens, a first divergent angle changing element for changing a divergent angle of light beams, which is capable of moving in the optical axis direction and placed in an optical path, and a coma aberration correction element for correcting coma aberration caused when the tracking device moves the objective optical element.

Abstract: An optical pickup apparatus for recording and/or reproducing information on a first optical information recording medium and a second optical information recording medium includes: a first light source emitting a first light flux with a wavelength ?1; a second light source emitting a second light flux with a wavelength ?2; and an objective lens of a finite conjugate type converging the first and second light fluxes. The objective lens has astigmatism for the first light flux, and the direction of occurrence for the astigmatism is the same as the direction in which astigmatism of the first light flux resulting from tracking is reduced. Further, an image height of the objective lens in the direction of tracking is within a prescribed range and astigmatism of the objective lens takes the minimum value.

Abstract: This invention provides an optical pickup apparatus which includes a plurality of light sources, a beam shaping element which is arranged in an optical path through which a light beam emitted from at least one of the light sources passes, and an optical system which includes a divergence angle conversion element and an objective lens and is arranged in an optical path through which the light beams emitted from the plurality of light sources pass, and records and/or reproduces information by condensing, through the objective lens, the light beam emitted from each light source on the information recording surface of a corresponding optical information recording medium. An almost elliptical cross-sectional shape of the light beam which enters the beam shaping element is shaped into a cross-sectional shape closer to an almost circular shape or a circular shape, and the light beam emerges from the beam shaping element.

Abstract: An objective optical element for use in an optical pickup apparatus, includes an objective lens to converge the light flux emitted from the first and second light sources; and an optical functional surface including a common region and an exclusive region. When a first optical information medium is used, a sine condition unsatisfied-amount whose value is maximum exists on the common region. The following formula is satisfied: 0.5?COMA2/COMA1?1.0 where COMA1 is a coma aberration (?1 rms) when a light flux goes slantingly to be incident with a view angle of 1° onto the objective optical element when the first optical information medium is used, and COMA2 is a coma aberration (?2 rms) when a light flux goes slantingly to be incident with a view angle of 1° onto the objective optical element when the second optical information medium is used.

Abstract: An optical pickup apparatus having a light source unit including a plurality of light emitting, a beam regulating element to regulate a light flux emitted from the light source unit so that the an angle of divergence of the light flux emitted from the light source unit is changed to a first direction and/or a second direction, wherein a distance from each of the light emitting element to a surface of a protective layer that protects the recording surface is constant regardless a type of the optical information recording medium.