Optical detector, optical pickup and optical information reproducing apparatus using optical pickup

Abstract

An optical pickup has a semiconductor laser having two laser sources of different wavelengths disposed in the same package, one diffraction grating and one optical detector. A plurality of light reception areas each having four divisional light reception planes of a -character shape are disposed at positions where light beams reflected from an optical disc are applied. A focus error signal is generated by an astigmatism method by using independently these light reception areas and a tracking error signal is generated by a differential phase detection method by using one or both the light reception areas.

What is claimed is:  
     
         1 . An optical detector comprising no laser source in a package of said optical detector, comprising: 
 a first light reception area column in which three light reception areas are arranged in an order of a third light reception area, a first light reception area and a fourth light reception area, said first light reception area column being irradiated with a light beam having a first wavelength;    a second light reception area column in which three light reception areas are arranged in an order of a fifth light reception area, a second light reception area and a sixth light reception area, said second light reception area column being irradiated with a light beam having a second wavelength larger than said first wavelength;    wherein each of intervals between centers of each of said third, first and fourth light reception areas arranged in said first light reception area column is larger than each of intervals between centers of each of said fifth, second and sixth light reception areas arranged in said second light reception area column.    
     
     
         2 . An optical detector according to  claim 1 , wherein each of said third, first, fourth, fifth, second and sixth light reception areas is divided with a first division line and a second division line which intersect with each other, and each of said third, first, fourth, fifth, second and sixth light reception areas has four light reception planes.  
     
     
         3 . An optical detector according to  claim 1 , wherein each of said third, first, fourth and second light reception areas is divided with a first division line and a second division line which intersect with each other, and each of said third, first, fourth and second light reception areas has four light reception planes, and each of said fifth and sixth light reception areas is not divided and has one light reception plane.  
     
     
         4 . An optical detector according to  claim 1 , wherein each of said third, first, fourth and second light reception areas is divided with a first division line and a second division line which intersect with each other, and each of said third, first, fourth and second light reception areas has four light reception planes, and each of said fifth and sixth light reception areas is divided with a division line in a direction intersecting with a longitudinal direction in which said light reception areas of said second light reception area column are arranged, and each of said fifth and sixth light reception areas has two light reception planes.  
     
     
         5 . An optical detector according to  claim 1 , wherein each of said first and second light reception areas is divided with a first division line and a second division line which intersect with each other, each of said first and second light reception areas having four light reception planes, and each of said third and fourth light reception areas is divided with a division line in a direction intersecting with a longitudinal direction in which said light reception areas of said first light reception area column are arranged, each of said third and fourth light reception areas having two light reception planes, and each of said fifth and sixth light reception areas is not divided and has one light reception plane.