Semiconductor Laser Pickup for Optical Video Disk Player

Almost five years have passed since the concept of the optical video disk system was first presented, and several kinds of systems have been developed these few years. 1,2,3,4 Recently, the standardization of these confused optical video disks was made and optical video disk player systems have already reached the stage of commercial development.5 Optical video disk systems offer several advantages to mechanical and capacitive video disk systems. High image quality, still and slow motion picture capability are some of its chief attractions. Unfortunately, large, complicated, and expensive optical pickups still remain a problem. Part of the difficulties is the use of the He-Ne laser as a light source. Although the He-Ne laser is one of the most stable and compact gas laser among several commercial available lasers, its size, over 200mm length and 30mm in diameter, is still too large for a compact optical pickup. Moreover, high voltage power supply of over 1.5KV are not desirable for home use systems. In addition, the optical system used in the pickup is quite complex because separate laser beams are used to detect the auto-focusing signal, the tracking signal, and the video signal. These factors make for a very expensive overall cost in labor for manufacturing and maintenance.