Konica Corporation

Konica-minolta Holdings, Inc.

Hidekazu Totsuka

Yuichi Atarashi

Shinichiro Saito

Kohei Ota

Kiyono Ikenaka

Katsuya Sakamoto

Mitsuru Mimori

An objective optical element of an optical pickup apparatus has a magnification m1 satisfying the following formula for a light flux of the wavelength &#x3bb;:&#x2212;1/7&#x2266;m&#x2266;&#x2212;1/25 and |m|&#x3c;|Mwhere Mis an optical system magnification from the first light source to the first optical information recording medium for a light flux of the wavelength &#x3bb;. 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 &#x3bb;. 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.

Objective optical element and optical pickup apparatus

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&#x2266;COMA2/COMA1&#x2266;1.0where COMA1 is a coma aberration (&#x3bb;1 rms) when a light flux goes slantingly to be incident with a view angle of 1&#xb0; onto the objective optical element when the first optical information medium is used, and COMA2 is a coma aberration (&#x3bb;2 rms) when a light flux goes slantingly to be incident with a view angle of 1&#xb0; onto the objective optical element when the second optical information medium is used.

Objective optical element, optical pick-up apparatus, and optical information recording reproducing apparatus

An objective lens for use in an optical pickup apparatus in which first and second light sources are provided on a same flat surface, converges each of the light fluxes from the first and second light sources onto an information recording plane through each of transparent substrates of a first and second optical information recording mediums and has a coma aberration of 0.015 &lgr;1 rms or less when recording or reproducing information is conducted for the first optical information recording medium, and a coma aberration of 0.015 &lgr;2 rms or less when recording or reproducing information is conducted for the second optical information recording medium.

Objective lens for optical pick-up apparatus and optical pick-up apparatus

Growing community of inventors

Hachioji, Japan

Hidekazu Totsuka