Optical disc device and optical disc discriminating method

An optical disc device comprising:

• a laser light source for radiating a laser light beam illuminated via an objective lens on a signal surface of an optical disc;
• return light detection means for detecting the reflected light radiated from the laser light source and reflected from the signal surface of said optical disc;
• disc discriminating means for discriminating the type of said optical disc based on a detection output of said return light detection means;
• means for detecting tracking error signals of plural different types of different detection systems based on the detection output of said return light detection means;
• tracking means for displacing the objective lens along the radius of said optical disc responsive to said tracking error signals for tracking-controlling a laser spot of the laser light focussed on the signal surface of the optical disc;
• and
• controlling means for switching said detection system based on a discriminating output by said disc discriminating means for selecting one of said plural types of the tracking error signals responsive to the types of the optical discs, wherein said return light detection means includes first, second and third error signal generating means for performing pre-set calculations on plural detection signals selected from detection signals A, B, C, D, E, F, G and H from the photodetector for generating first, second and third tracking error signals and selection means for selecting one of said first, second and third tracking error signals.

A method of discriminating a loaded one of plural types of optical discs for data recording/reproduction using an optical disc device which includes a laser light source, a light detector, a processor, and discriminating, tracking and tracking error circuitry, comprising the steps of:

• radiating a laser light beam illuminated via an objective lens on a signal surface of an optical disc;
• detecting the radiated light reflected from a signal surface of said loaded optical disc;
• moving said objective lens in a sole focussing search operation such that a focal plane of said lens moves through a signal surface of said loaded optical disc;
• discriminating which of the plural types of said optical discs is the loaded one;
• switching tracking and detection systems based on a discriminating output for selecting one of plural types of tracking error signals responsive to the different types of the optical discs;
• and
• performing pre-set calculations on plural detection signals selected from detection signals A, B, C, D, E, F, G and H for generating first, second and third tracking error signals and selecting one of said first, second and third tracking error signals.