Implementation of Illuminance Measuring System with Silicon Photocell for Integral Stereolithography System

The illuminance on the imaging plane of integral Stereolithography system influences cured depth of resin and fabrication accuracy of part during building process. To control the cured depth of resin and fabrication accuracy, an illuminance measuring system using silicon photocell is developed. The illuminance measuring system consists of MCU, silicon photocell, gain adjustment circuit, I/V switching and amplifying circuit, RS-232 communication interface, LCD module and keyboard. The light illuminance signal received by silicon photocell is converted to weakly electric current signal, and current signal is converted to voltage signal and magnified via I/V switching and amplifying circuit, then the voltage signal is input to MCU to be processed. In terms of digital signal and the sensitivity of silicon photocell, the real illuminance value can be calculated. Measuring results are displayed with LCD and sent to PC with RS-232 communication interface. The lmplementation of illuminance measuring system provides a tool for control fabrication accuracy of part in building process for the integral Stereolithography system.