FOCUSING DETECTOR AND CONTROLLER FOR OPTICAL DISC REPRODUCER

PURPOSE:To detect focusing, by making a reflected light from a disc incident to two concentric photodetectors via a lens having a circular cone-shaped refraction plane. CONSTITUTION:A reflected light from a disc is made incident to a photodetector 18 having two concentric elements 18A, 18B via a len...

Ausführliche Beschreibung

Gespeichert in:

Bibliographische Detailangaben
Hauptverfasser:	SHINO KUNINOBU, OOKI YUTAKA
Format:	Patent
Sprache:	eng
Schlagworte:	INFORMATION STORAGE INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS OPTICS PHYSICS
Online-Zugang:	Volltext bestellen
Tags:	Tag hinzufügen Keine Tags, Fügen Sie den ersten Tag hinzu!

Beschreibung
Zusammenfassung:	PURPOSE:To detect focusing, by making a reflected light from a disc incident to two concentric photodetectors via a lens having a circular cone-shaped refraction plane. CONSTITUTION:A reflected light from a disc is made incident to a photodetector 18 having two concentric elements 18A, 18B via a lens 17 of circular cone- shaped refracted plane. At a suitable focusing state, a spot S of the reflected light appears at a boundary of the photodetectors 18A, 18B as a center. The spot appears at the inside element 18B at under-focusing and it appears at the outer elements 18A at overfocusing. A focus controlling signal is obtained by taking a difference of the output of the two photodetectors.