DVD reading-writing pick-up head employing multiple wavelengths

Year	Description
1999	Invention patented by Zu-Wen Chao and Yuan-Chin Lee on August 15th, 1999. Abstract: This invention relates to a DVD reading-writing pickup head employing multiple wavelengths for data access on an optical record medium. With the configuration of the pickup head of the present invention, the number of the used optical elements is minimized. The pickup head of the present invention includes a cemented birefringent prism, a plurality of objective lenses, quarter-wavelength plates and laser sources and a photo detector. The cemented birefringent prism is used to refract the laser beams generated by the laser sources into an incident branch and split the laser beams and a reflected branch reflected from the optical record medium.
Source: selected by the editor from original sources.

Invention: DVD reading-writing pick-up head employing multiple wavelengths