At ISOM/ODS, Sony Corp. reported that it has developed a small-sized optical pickup module that supports the Blu-ray Disc standard for second-generation recording and playback equipment. The second-generation product designs require miniaturization of the optical pickup for stationary recorders and installation of recording/playback equipment in the mobile apparatuses, including laptop PCs. The technical development for the first-generation products already has been completed.
This time, in the second-generation products, Sony aimed at reducing the number of optical-system parts to half, from 16 to eight. The outside dimensions are held down to 11mm by 6mm by 4.1mm by integrating the main optical parts in the optical pickup. Being as thin as 4.1mm, Sony says that installation in thin recording/playback equipment for laptop PCs is also possible.
The module is constructed with a blue-violet semiconductor laser, photodetectors, a polarizing prism, a mirror, a diffraction grating, a cylindrical lens, hologram elements and a half-wave plate. As for the semiconductor laser element, a product manufactured by Sony Shiroishi Semiconductor Inc. is adopted. The power consumption of the semiconductor laser is about three times higher than infrared-semiconductor lasers for mini discs. Therefore, this time, a structure where the heat of the laser is released via lead frames is adopted. On the package embedded with a lead frame, semiconductor laser elements, the 45-degree mirror for the laser, photodetectors (PDIC) and a half-wave plate are installed, and finally combined with parts made of acrylic resin (PMMA) with the prism, lens and other functions.