Focus detecting optical head

Details Focus detecting optical head Focus detecting optical head

1990-02-13

1993-03-16

Chin, Tommy P.

Dynamic information storage or retrieval

With servo positioning of transducer assembly over track...

Optical servo system

369 4441, 369109, 369112, C11B 700

Patent

active

051950715

ABSTRACT:
An optical head for detecting defocuses of a target comprises a waveguide element having a substrate and an optical waveguide layer formed thereon. An optical coupler and one or more pairs of photodetectors are integrated with the waveguide layer. Light reflected back from the target is coupled with the waveguide layer through the coupler and then waveguided toward the photodetectors while being collected. Each of the photodetectors can detect the waveguided light so that a focus error signal can be obtained from the difference of the outputs of the photodetectors. The photodetectors of each pair are spaced from each other in a propagation direction of the waveguide layer so that one of the photodetectors can block off a fraction of the waveguided light from the other photodetector when the target surface is in focus. In another form, two pairs of photodetectors are spaced forward and rearward from the focused position of the waveguided light, respectively, with respect to a propagation direction of the waveguide layer so as to receive different portions of the waveguided light.

REFERENCES:
patent: 4815059 (1989-03-01), Nakayama et al.

Affiliated with

Also associated with

Rating

Focus detecting optical head does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Focus detecting optical head, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Focus detecting optical head will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-356001