Optical pickup device and optical disc apparatus

An optical pickup device comprising:

• a semiconductor laser diode which emits an optical flux;
• an objective lens which converges the optical flux emitted from said semiconductor laser diode and radiates the optical flux to an optical disc;
• am optical branching element which branches an optical flux reflected from said optical disc;
• and
• a photodetector which receives an optical flux branched by said optical branching element and has a plurality of light receiving parts,
• wherein:
• said optical branching element has three areas A, B and C;
• said area C includes a center of said optical branching element;
• said area A is spaced in a track direction of the optical disc relative to said area C;
• said area B is spaced in a radial direction of the optical disc relative to said area C;
• said photodetector detects a reproduction signal from optical fluxes diffracted in said areas A, B and C;
• said plurality of light receiving parts which detect the beam diffracted in said area A of said optical branching element are aligned in a direction substantially perpendicular to a direction corresponding to the track of said optical disc;
• and
• said plurality of light receiving parts which detect the beam diffracted in said area B of said optical branching element are aligned in a direction substantially parallel to a direction corresponding to the track of said optical disc.

An optical disc apparatus comprising:

• an optical pickup device including:
• a semiconductor laser diode which emits an optical flux;
• an objective lens which converges the optical flux emitted from said semiconductor laser diode and radiates the optical flux to an optical disc;
• an optical branching element which branches an optical flux reflected from said optical disc;
• and
• a photodetector which receives an optical flux branched by said optical branching element and has a plurality of light receiving parts,
• wherein:
• said optical branching element has three areas A, B and C;
• said area C includes a center of said optical branching element;
• said area A is spaced in a track direction of the optical disc relative to said area C;
• said area B is spaced in a radial direction of the optical disc relative to said area C;
• said photodetector detects a reproduction signal from optical fluxes diffracted in said areas A, B and C;
• said plurality of light receiving parts which detect the beam diffracted in said area A of said optical branching element are aligned in a direction substantially perpendicular to or substantially parallel to a direction corresponding to the track of said optical disc;
• a laser lighting circuit which drives said semiconductor laser diode in said optical pickup device;
• a servo signal generator circuit which generates a focusing error signal and a tracking error signal by using signals detected by said photodetector of said optical pickup device;
• and
• an information signal reproducing circuit which reproduces an information signal recorded in said optical disc.

An optical disc apparatus comprising:

• an optical pickup device including:
• a semiconductor laser diode which emits an optical flux;
• an objective lens which converges the optical flux emitted from said semiconductor laser diode and radiates the optical flux to an optical disc;
• an optical branching element which branches an optical flux reflected from said optical disc;
• and
• a photodetector which receives an optical flux branched by said optical branching element and has a plurality of light receiving parts,
• wherein:
• said optical branching element has three areas A, B and C;
• said area C includes a center of said optical branching element;
• said area A is spaced in a track direction of the optical disc relative to said area C;
• said area B is spaced in a radial direction of the optical disc relative to said area C;
• said photodetector detects a reproduction signal from optical fluxes diffracted in said areas A, B and C;
• said plurality of light receiving parts which detect the diffracted in said area A of said optical branching element are aligned in a direction substantially perpendicular to a direction corresponding to the track of said optical disc;
• and
• said plurality of light receiving parts which detect the beam diffracted in said area B of said optical branching element are disposed in a direction substantially parallel to a direction corresponding to the track of said optical disc;
• a laser lighting circuit which drives said semiconductor laser diode in said optical pickup device;
• a servo signal generator circuit which generates a focusing error signal and a tracking error signal by using signals detected by said photodetector of said optical pickup device;
• and
• an information signal reproducing circuit which reproduces an information signal recorded in said optical disc.