Sigma Koki (シグマ光機株式会社) is a supplier of optical equipment and devices for a broad range of applications from R&D to production equipment. It offers manufacturing equipment such as a 5-axis machining center, CNC lens polishing machine, optical coating machine, ring polisher, near field etching system, CNC lathe machine, ultrasonic cleaning machine, etc. The company also provides testing and measuring equipment that includes a spectrophotometer, scanning electron microscope, 3d optical surface profiler, laser calibration system, atomic force microscope, focometer, cleanrooms, and other products.