Papers by Keyword: DVD

Abstract: DVB-T system is a hi-tech product that integrated software, hardware, mechanism, optics all-in-one. It includes digital television's decoding, error correction, standard compatible, frequency search, DVD servo system, pick-up trace, DVD data stream decoding, driving for TFT-LCD, lithium battery's charge/discharge control, power supply management, different work mode's switch, complex machine structural design and so on. Needs software, Hardware, Structural engineers' cooperation, every function needs muck complex technology support.

Abstract: For Ag film used for storage media, it is required to have heat-resistant, anti-constant temperature, anti-constant humidity characteristics and corrosion resistance, while the high reflectivity of Al is maintained. An Ag thin film (additive elements Pd, Cu and P) was produced on glass substrates and various heat treatments were conducted. Then, the fine structure on this thin film was observed by AFM, and fine structure evaluation in the inside was carried out by in-plane diffraction and X-ray diffraction. In addition, residual stress analysis was performed. These results were compared and examined, and the fine structure and physical properties in a metallic thin film were evaluated.

Abstract: A novel design of triple-wavelength design for a compact optical pickup head is presented here. We propose the use of two rhomboid beam-splitter prisms for HD-DVD, DVD and CD devices to align signals with three different wavelengths on the same optical axis. The light is collimated by a collimating lens. The parallel beams are incident on the wavelength selector. The wavelength selector separates the wavelengths with different numerical apertures. The different wavelength signals are focused on the disc by an objective lens.

Abstract: DVD player is regarded as a mature and low-cost commercial product for multimedia and computer data storage. Fundamentally the pickup head is a key part of the DVD player and it uses focused laser beam to read the data on the DVD disk tracks whose width is approximately 0.74μm. This research focused on the control aspect applied to a DVD pickup head for the development of an auto-focusing laser probe. Practically, the laser pickup head has the S-curve linearity property with the measuring range of about 7μm [3]. To extend the measurement range, the feedback control of VCM in the focusing direction is needed. This study used Genetic Algorithms (GAs) to search for appropriate PID gains for VCM control. In MATLAB simulation, the GAs tuning scheme could produce the optimised gains within less than 0.02 sec. Moreover, the experimental results demonstrated that the VCM auto-focusing measurement range could be extended to 1350μm.