一.引言光学测长仪器已从目视发展到投影,再进一步提高仪器的性能,就得采用光、机、电相结合的新原理。应用光电瞄准提高瞄准精度和减轻劳动强度就是途径之一。早在几十年前就已经利用光电瞄准来介决标尺的高精度计量问题,如瑞士Sip厂在1945年就利用光电显微镜检定标尺。但是光电瞄准用于测长仪器上还是最近的事。如民德Zeiss厂生产的光电瞄准立式测长仪,1976年在上海民德工业展览会上展出;瑞士 I. INTRODUCTION Optical length measuring instruments have been developed from the visual to the projection, and then further improve the performance of the instrument, you have to use the light, machine, electric combination of new principles. One of the ways to improve the aiming accuracy and reduce the labor intensity by using photoelectric targeting. As early as decades ago, photoelectric sighting has been used to determine the accuracy of scale measurement problems, such as the Swiss Sip factory in 1945 on the use of optical microscopy scale. But optoelectronics aimed at measuring instruments is still the most recent thing. Such as the German German Zeiss factory production of photoelectric aiming vertical measuring instrument, exhibited in Shanghai Midek Industrial Exhibition in 1976; Switzerland