OPTICAL ROTARY ENCODER

PROBLEM TO BE SOLVED: To automate soldering and protect a circuit board when a photodetecting element is mounted to the circuit board, by placing the photodetecting element on an auxiliary substrate of a through hole type having an anode conductor projecting at an end face and connecting the photodetecting element as one surface-mounted part onto the circuit board by soldering. SOLUTION: A photodetecting element 1 is placed and securely fixed on an auxiliary substrate 2, thereby constituting an integrated coupled member. The coupled member is loaded on each pad 71 on a surface of a circuit board 4 which corresponds to each semi-circular end face through hole 3. The member is loaded at a position surrounded by other pads 71 already loaded and fixed on an upper surface of the circuit board 4. The semi-circular end face through hole 3 and pad 71 are, as a surface-mounted part of the circuit board 4, automatically soldered, for example, in a reflow furnace (automatic soldering device) by heating/melting and cooling a solder. The photodetecting element 1 is accordingly surely and easily connected to the upper face of the circuit board 4 via the semi-circular end face through holes 3 of the auxiliary substrate 2.