When detecting PCB board hollow, ordinary photoelectric sensor, the light source may penetrate the PCB board, resulting in unstable detection signal or missed detection. And SENPUM Special Photoelectric Sensors PH2-V Series The line spot will emit a long beam to cover the inspection area, and can output a stable signal as long as there is a light source to the PCB board. It is also suitable for PCBs with complex colours, or PCBs with uneven soldered parts.