针对平行光束法的不足,探讨了在应力仪上实现准聚焦法的可行性。研究表明,采用准直入射光管和大张角平行接收光阑的几何布置,不仅有效地减小了光斑面积,可测小范围的应力,而且大幅度地提高了接收强度,缩短了测试时间。较之平行光束法,准聚焦法仍允许试样有一定的设置偏差,应力测定精度满足试验要求。 Aiming at the deficiency of parallel beam method, the feasibility of quasi-focusing method on stress meter is discussed. The research shows that the geometric arrangement of collimated incident light pipe and large aperture parallel receiving aperture not only reduces the spot area effectively, but also can measure the stress in a small range, but also greatly improves the receiving intensity and shortens the test time. Compared with the parallel beam method, quasi-focusing method still allows the sample to have a certain set of deviations, stress measurement accuracy to meet the test requirements.