微机电系统与微机械零件的内部微缺陷需要高精度、强穿透性的非接触检测技术。目前缺少这样内部微缺陷的检测方法。针对上述问题，设计了超声与数字全息成像的复合系统。该系统结合了超声检测的强穿透能力和数字全息成像技术的高分辨率。该系统包括近场超声子系统、数字全息子系统和同步控制子系统。在近场超声子系统中，产生的近场超声波场穿过样品的内部缺陷，在样品表面形成表面超声波场，再通过数字全息子系统测量和分析这个表面超声波场的瞬态形貌，分析声波场中包含的内部缺陷信息。实验结果表明：该系统通过对超声波场的分析，可以测量出超声波场的瞬态三维形貌，并且可以有效的检测出50 μm的内部缺陷。

Non-contact detection of internal micro-defects of the micro-electro-mechanical system and minimechanism required a high accuracy and strong penetration test. The current detection methods were difficult to achieve high precision while also having strong penetrating power. In response to the above problems, a composite system of ultrasonic detection and digital holography imaging was designed. Ultrasonic detection technology had strong penetrating power, and digital holographic imaging had higher resolution. The composite system designed included a near-field ultrasonic subsystem, an digital holographic subsystem and a synchronous control subsystem. In the near-field ultrasonic subsystem, the generated near-field ultrasonic wavefields passed through the internal defect of the sample and formed the surface ultrasonic wavefield on the surface of the sample. The digital holographic subsystem mainly measured and analyzed the transient morphology of the surface ultrasonic wavefields, and the internal defect information contained in the surface ultrasonic wavefield could be analyzed. The experimental results show that the system can measure the transient 3D topography of the ultrasonic wavefield by analyzing the ultrasonic wavefield, and can effectively detect internal defects of 50 μm.