Konica Minolta Opto, Inc.

Konica Corporation

Konica-minolta Holdings, Inc.

Kiyono Ikenaka

Yuichi Atarashi

Tohru Kimura

Kohei Ota

Shinichiro Saito

Mitsuru Mimori

Eiji Nomura

Katsuya Sakamoto

Kenji Ogiwara

Junji Hashimura

Mika Wachi

Hidekazu Totsuka

Tatsuji Kurogama

Katsuya Yagi

Koji Honda

An optical system has an optical functional surface including a common region used for conducting information recording and/or reproducing for both of a first optical information recording medium and a second optical information recording medium. The common region comprises a refractive surface of an imaginary basic aspherical surface and a optical path difference providing structure in which plural ring-shapes zones are separated around the center of an optical axis and neighboring ring-shaped zones are displaced to each other in a direction of an optical axis so as to cause an optical path difference obtained by multiplying a predetermined wavelength &#x3bb;s (&#x3bb;s&#x3c;&#x3bb;) with almost an integer. The refractive surface of the imaginary basic aspherical surface is structured such that a spherical aberration becomes under on the first information recording medium and a spherical aberration becomes over on the second information recording medium.

Optical pickup device and objective lens used in the same

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.

Optical pickup apparatus and objective optical element

An optical pickup apparatus for conducting recording and/or reproducing information for a first optical information recording medium including at least a transparent protective substrate, a first information recording surface, and a second information recording surface which are laminated in this order from a light source side along an optical axis, comprising:

Optical pick-up apparatus

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 &#x3bb;1 and a second wavelength &#x3bb;2, and a second phase structure corrects at least one of a spherical aberration generated when the first wavelength &#x3bb;1 is changed in a range of &#xb1;10 nm, a best image point movement generated when the first wavelength &#x3bb;1 is changed in a range of &#xb1;10 nm, and a spherical aberration generated when environmental temperature is changed.

Objective optical element and optical pickup apparatus

An optical pickup apparatus comprises first, second and third light sources to emit light fluxes of wavelength &#x3bb;and &#x3bb;for conducting recording and/or reproducing information for first, second and third optical information recording mediums having respective protective substrates of thickness t, tand tand 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 &#x3bb;, on the second optical information recording medium with n-th order diffracted-light ray of the wavelength &#x3bb;, and on the third optical information recording medium with k-th order diffracted-light ray of the wavelength &#x3bb;generated by the diffractive optical element respectively, wherein one of m, n and k is different from one of other two numbers.

Optical pickup apparatus and optical element

An optical pickup apparatus, comprising: a light source to emit a light flux; a light converging system including an objective lens to converge the light flux emitted from said light source onto an optical information recording medium; a first diffraction element placed within an optical path up to the optical information recording medium; a light flux splitting element that is placed within the optical path from said light source up to the optical information recording medium and that splits an incident light flux emitted by the light source; a monitor element that receives a light flux split by said light flux splitting element and outputs a signal according to a received light amount; a second diffraction element placed between said light flux splitting element and said monitor element; and a control section that controls the drive of said light source according to the signal from said monitor element.

Optical pickup apparatus with temperature compensation

An optical pickup apparatus for recording and/or reproducing information for an optical information recording medium, comprising a light converging optical system including a coupling lens and an objective lens, wherein a first diffraction structure is installed on the objective lens, and a second diffraction structure is arranged on the coupling lens, whereby the spherical aberration and chromatic aberration caused by the difference in the thickness of the protective layer are corrected in the light converging optical system as a whole.

Optical pickup apparatus

The present invention provides an optical pickup apparatus including: a first light source; a second light source; and a light-converging optical system including a coupling lens and an objective lens. The coupling lens includes a first diffractive structure. The optical pickup apparatus satisfies a predetermined condition according to the chromatic aberration, focal length, and dispersion of the material.

An objective lens is provided for an optical pickup apparatus at least reproducing information for a first optical disc, and recording and/or reproducing information for second and a third optical discs. The objective lens includes an optical surface including a common area including a diffractive structure having a cross section in a serrated shape and divided into a plurality of ring-shaped zones. Refractive index differences between media arranged at both side of the optical surface for a light flux with one and the other wavelength satisfy a predetermined condition, and the objective lens satisfies a predetermined conditions defined by using an approximate coefficient which makes a Pearson's correlation coefficient R satisfy 0.99998&#x2266;R when a depth parallel to the optical axis of step differences between the ring-shaped zones at a vertical distance from the optical axis is approximated by a least squares method.

Objective lens and optical pickup apparatus

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 &#x3bb;(350&#x2266;&#x3bb;(nm)&#x2266;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.

Optical pickup apparatus and optical information recording and/or reproducing apparatus

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 &#x3bb;and the second light flux with a wavelength of &#x3bb;but in the case where the protective substrate tof the second optical information recording medium and the protective substrate tof 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.

The present invention provides an optical pickup apparatus including a first light source, a second light source, a third light source, and a light-converging optical system including an objective lens. The objective lens includes at least one optical surface with a diffractive structure. The diffractive structure includes a plurality of ring shaped zones. Each of the ring shaped zones is concentrically arranged around an optical axis and includes a step difference extending along the optical axis. In the objective lens, the predetermined conditions according to the offence against a sine condition, an average of step differences of the plurality of ring shaped zones, a focal length, and a magnification, are satisfied.

An objective optical element for use in an optical pickup apparatus first-third light sources emitting first-third light fluxes and a light converging optical system, includes a first optical path difference providing structure for providing an optical path difference which provides a substantial phase change to the third light flux and does not provide a substantial phase change to the first and second light fluxes; and a second optical path difference providing structure for providing an optical path difference to the first light flux, the second light flux and the third light flux, wherein the objective optical element converges the first-third light fluxes through the protective layers with the thicknesses t1-t3 onto an information recording surface of the first-third optical information media respectively.

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Hino, Japan

Kiyono Ikenaka