Micro-encoder using image obtained by ball lens assembled inside wafer

Abstract

An absolute micro-encoder based on the code imaging is developed. The ball lens (<1>300 f.lITI) is asse mbled inside the cavity between the pyrex glass lid and suspensions in the handling Si layer of the SOl wafer. The photodiode array is prepared in the device Si layer. The image of the scale is incident on the backside of the photodiodes. The electrical wiring to photodiodes does not disturb the optics. The curren t signal shows the sufficient contrast for resolv ing the maximum length code having the minimum line width of 13.6 !lI11.

Absolute Position Coding Method for Angular Sensor—Single-Track Gray Codes

“…Absolute angular measurement is the critical part for the accuracy of many precision control systems, such as the positioning of aerospace cameras, star positioning in astronomical observation, and precision weapon positioning in the national defense area [1,2,3,4,5]. The most widely used angular sensor is the absolute rotary encoder in which the coding disc carries all the unique angular information for each position in a magnetic or an optical way that can be recovered immediately after a power outage [6,7].…”