基于二元声学的方法提出了一种折射/衍射混合声透镜设计方案,该声透镜在对光声信号进行二维成像时体现出了极大的优越性,与单声透镜相比,除了有实时成像、成像焦深较大且可以利用时间分辨技术实现层析成像的优点外,还可以利用二元声学透镜独特的色散特性校正单声透镜的轴向色差,可以极大提高成像的分辨力。通过计算机模拟了有一定带宽的点声源通过该声透镜像面上的点扩展函数,与经单声透镜的结果比较,可以看出点扩展函数弥散斑得到明显改善,极大地消除色差对成像质量的影响。

The design project of a diffractive-refractive hybrid acoustic lens based on binary acoustical principle is presented. In photoacoustic imaging, the diffractive-refractive hybrid acoustic lens, comparing with single acoustic lens, has many advantages including real-time imaging, long imaging focal depth, using time-delay to realize tomographic imaging and especially its achromatization merit to increase imaging resolution. It is simulated that point spread function received after point acoustic source with band width passes through the diffractive-refractive hybrid acoustic lens. Compared with that through single acoustic lens, point spread function is greatly improved in the simulated figure and the influence of axial chromatism on imaging quality is partly eliminated.