Patent ID: 11874144
Assignee: LI LIN
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 23:
24. A method for determining a displacement measurement, comprising:
scanning a code carrier comprising an absolute position reference code channel (APRCC) comprising at least one pit line or one missing pit line, which is uniquely distributed among one or more neighboring pit lines, and a relative displacement measurement code channel (RDMCC) comprising an arrangement of one or more pit lines in a circumferential direction and one or more bump lines, using an optical laser assembly (OLA), by:
controlling at least one 2-D coil actuator with a power driver to adjust a position of an optical objective lens inside of the OLA, drive an objective lens of the OLA to a position on top of the APRCC to read a first group of RF signals for the absolute position reference, focus a laser beam on the one or more bump lines and the one or more pit lines in a direction perpendicular to a surface of the data storage medium, decode, with a photo detector, the laser beam reflected off the one or more bump lines and the one or more pit lines in the APRCC to generate a plurality of electronic signals and to obtain relative displacement reference information, and drive the objective lens of the OLA to a position on top of the RDMCC to read a second group of RF signals for an incremental displacement measurement;
emitting a laser beam using a laser diode onto the code carrier;
decoding the laser beam after it reflects off the code carrier using a signal processing unit to obtain a group of electric signals; and
calculating the displacement and/or the velocity based on the obtained electric signals.