Single surface diffractive element for optical pickup heads
US5652744A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 8, 1996 |
| Grant date | Jul 29, 1997 |
| Priority date | — |
| Expiry date | Feb 8, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0912
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical pickup device including a lighting source, a condensing apparatus, a diffracting means, and a light detector. The light source generates and emits a light beam to the diffracting means. The diffracting means includes a center region and an outer region which encloses the center region. As the light travels from the light source towards the optical storage medium the main zero-order beam which reads the information on the disk encounters only the center region of the diffracting means while the two sub-beams used for track following are created as +1 and -1 diffraction orders from the outer region of the diffracting means. The three beams reflected from the recording medium all pass through the center region of the diffracting means and are diffracted in the direction of the detector therefrom. The light detector consists of multiple detector elements which convert the light that shines upon them after reflection from the recording medium into electronic signals containing the information that was recorded on the medium.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.