US Patent 11853484 Waterproof electronic pen

A highly reliable waterproof electronic pen includes a board holder in a board housing including a recessed portion having an opening over a lower surface of the recessed portion. A circuit board is housed in the recessed portion of the board housing. Circuit components easily affected by heat are installed on a first surface of the circuit board, and circuit components not easily affected by heat are installed on a second surface of the circuit board. A thermosetting resin formed over the second surface of the circuit board when the circuit board is housed in the recessed portion seals the opening over the lower surface of the recessed portion of the board housing.