Patent Application
20070286003
These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
Reference is now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The following provides a detailed description of a temperature gain compensation system and method thereof for reducing the gap between two tracks in a label laser etching process and improving the quality of the laser-etched disc label.
It is to be understood that the horizontal moving distance of the lens is directly proportional to the tracking coil terminal voltage and is inversely proportional to the tracking coil resistance in a constant temperature situation. Therefore, the relationship between the horizontal moving distance of the lens and the tracking coil terminal voltage can be determined. Moreover, it can be surmises that the temperature depending tracking coil terminal voltage using a triangular geometric relationship. Wherein the horizontal moving distance of the lens is equal to the track distance, and the purpose is that all track distance are constant.
Please refer to
However in the label laser etching process, the temperature is not constant, and the tracking coil resistance depends on the temperature variation of the tricking coil. So the track distance is reduced with the rising temperature when the tracking coil terminal voltage keeps constant. Therefore, it must compensate the tracking coil terminal voltage for the track distance change.
Now assuming that there is a higher temperature T in next track burning process, and the tracking coil terminal voltage becomes V2 (point E in
Therefore, the purpose is to find the next track tracking coil terminal voltage. By a triangular geometric relationship between triangle CFD and CHE, it can be found the next track tracking coil terminal voltage. In
To find the next track tracking terminal voltage in the specific temperature, just obtain the track distance, the initial temperature of the track burning process, the initial tracking coil terminal voltage, and the temperature coefficient of the tracking coil resistor from the optical read/write head module specification. Then using the triangular geometric relationship is described above to acquire the next track tracking terminal voltage. Therefore a temperature compensator can dynamically receive and process a temperature signal from a temperature sensor to obtain a temperature difference, and calculate a feedback control signal by the temperature difference to compensate the terminal voltage for remaining the track distance.
Please refer to
The servo device 306 in this embodiment is an optical read/write head module and contains a lens 308, a focusing coil 310, a tracking coil 312, a sled motor 314, and the temperature sensor 316. The focusing coil 310 and the tracking coil 312 are used to control the lens 308 to move in the vertical and horizontal direction to focus the laser beam and burn a track. The lens 308 is mounted on the sled motor 314. Therefore, the sled motor 314 is used to move the lens 308 to a predetermined position. The temperature sensor 316 is use to transmit the temperature signal of the optical read/write head module to the temperature compensator 318.
In this embodiment, the burning signal is a disc label laser etching signal, and the temperature compensator can be realized in a semiconductor chip. In other embodiments the system could further comprise a nonvolatile storage module and the temperature compensator can be realized in a firmware stored in the nonvolatile storage module. Furthermore, the temperature compensator can be integrated into the DSP and executed by the DSP.
To describe the whole temperature gain compensative control method for disc label laser etching in detail, please refer to
The feedback control signal comprises a tracking coil terminal voltage value to adjust the lens motion of the servo device. Therefore, the tracking coil terminal voltage value compensates the tracking coil resistance which changes with the temperature and remains the constant track distance.
In view of the foregoing, step 408 describes that the temperature sensor 316 transmits a temperature signal to the temperature compensator 318 dynamically, and the temperature compensator compares the initial temperature with the temperature signal to obtain the temperature difference. Subsequently, step 410 describes that the temperature compensator 318 calculates the feedback control signal using the triangular geometric relationship that is described above. The feedback control signal contains the terminal voltage value of the tracking coil 312. After being processed and amplified by the DSP 302 and driver IC 304, the voltage value has become the tracking coil terminal voltage to compensate the tracking coil resistance changed with temperature.
To know the impact on the embodiment of this invention, please refer to
As described above, the temperature compensator receives the temperature signal from the temperature sensor dynamically and generates a feedback control signal. The feedback control signal can adjust the tracking coil terminal voltage. Thus, it can reduce the gap between two tracks in the disc label laser etching process and improves the quality of the laser-etched disc label.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
| Number | Date | Country | Kind |
|---|---|---|---|
| 95120261 | Jun 2006 | TW | national |
