[电] bipotential electrostatic lens, immersion electrosraic lens
shuāng diàn wèi jìng diàn tòu jìng ㄕㄨㄤ ㄉㄧㄢˋ ㄨㄟˋ ㄐㄧㄥˋ ㄉㄧㄢˋ ㄊㄡˋ ㄐㄧㄥˋ