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

Claim 0:
1. A displacement measurement system comprising:
a code carrier comprising:
a data storage medium and, within the data storage medium, 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;

a first composite subsystem comprising:
an optical laser assembly (OLA) comprising a first 2-D coil actuator that is configured to:
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, and
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;
a first signal processing unit;
a first power driver, which is configured to control the first 2-D coil actuator to focus or reposition the laser beam; and
a central control and signal output unit (CCSOU).