Nowadays, high-density disc and high-speed optical disk drive have become popular as optical disc has many merits
such as cost effectiveness, high data transfer rate, large storage capacity, removability and compatibility. In this paper, we
presented a compatible optical pickup actuator for next generation versatile disc (NVD) system. This actuator has high
AC sensitivities and good 2nd resonance frequency through finite element method (FEM), and the actuator model
properly satisfied the specifications for NVD system. The FEM analyses method is successfully applied to design the
optical pickup actuator.
The lens actuator is one of the most important mechanical-electrical components in optical disc systems. It is used for adjusting the attitude and position of the objective lens. When it works, the resonance vibration including the first resonance and higher order resonance will happen near the resonance frequency, which will weaken the servo control capability, thus additional damper glue is necessary to restrain the resonance magnitude. In order to obtain better damping performance, the location of the damper glue and the structure of the damping filler are very important to control the resonance magnitude. In this paper, according to the flow feature of the damper glue, damping models in focusing, tracking and tilting direction are established with the help of Oseen flow equation, and equivalent damping coefficients are derived. Some samples with the design parameters are fabricated and tested, the damping coefficients obtained form the experiment are compared with the theoretical results, which shows the validity of the proposed fluid model and the design method.
This paper deals with the actuator movement measurement for objective lens actuator in optical pickup. An optical pickup is an optical apparatus to record and/or reproduce information from an optical disc, and move in a radial direction on the optical disc. The objective lens actuator helps move an objective lens in a tracking direction, a focusing direction, and/or a tilting direction, spot the laser beam on a correct portion of the optical disc. It basically carries out tracking and focusing movements, i.e., a biaxial movement. For high recording density media, the optical pickup actuator requires a triaxial or quadriaxial movement including a tilting movement in addition to the existing biaxial movement. For information recording and/or reproducing correctly, the movement range of the actuator should be proper to accurately follow the disc deviation. Alternative methods of movement measurement have been proposed. One method employed now uses a plane plate reflecting laser beam which describes the movement. It requires two laser devices for tracking direction and the focusing direction measurement respectively. Here we propose a method for describing the tracking and focusing movements on one laser device. In this method an external cone is used, with the same weight as the objective lens. It could reflect laser beam back to the linear CCD. The diameter of the external cone base is equal to that of the objective, which is crucial for a stable placement. The ratio of height to width of the external cone is designed and optimized, so that to satisfy the accuracy of the movement measurement and minimize the device. Measurement with this method has proved satisfactory for certain CD/DVD optical pickup.
The lens actuator is the important mechanical-electrical component in the optical disk reading/recording system.
According to the error signals from the optical pickup reading/writing process, namely the focusing and tracking error
signals, the focusing coils as well as the tracking coils are applied the corresponding corrective current (or voltage), thus,
the force generated by the current-on coils in the magnetic field will real-time actuate the objective lens to make the
focusing spot precisely fall on the disc information track, realizing the data reading/writing. As wire suspension type, the
suspension model determines the wire design process. According to the material mechanics, the force distribution on the
wires is analyzed and the four wire suspension model is set up, thus, the wire parameters are designated and the natural
frequency as well as the static sensitivity of the moving part can be determined. After serial material experiments using
Instron 5848 Microtester, better treatment for the wire fabrication is adopted with 1.5 hour aging and sliver cover-layer.
Moreover, the actuator with the suspension wire is tested by the laser vibrometer and results show the good performance
of the actuator, which proves the feasibility of the suspension model. Although the suspension model is set up on the four
wire suspension actuator used in DVD-ROM, it can also be used in the six wire suspension actuator in the HD DVD and