微机械构件与微电子封装等一系列微机电结构正在向高密度、高集成度的方向发展，因此对微机电结构质量控制提出了越来越高的要求。针对微机械结构内部缺陷检测问题，提出了一种超声-激光全息复合无损检测方法。本文主要基于近场声学理论，研究近场超声波在微机械结构中的传播机制，旨在提高微机械结构内部缺陷检测的精度和可靠性。 针对基于法向质点振速声场重构过程的稳定性与可靠性问题，研究分析了波数域内的噪声特征，提出了一种改进的基于波数域滤波函数的降噪方法。通过基于点源激励的数值仿真算例，验证了该方法能够完善基于k-空间格林函数的重构效果，提高了近场声全息重构算法的抗噪声干扰能力。 针对传统瑞利积分无法描述圆形活塞近场区域声波分布问题，研究了基于空间傅里叶变换的换能器近场声特性。分析比较了不同波数成分的声场分布与声源大小、辐射频率及测量距离的关系，得出了传播波和倏逝波在空间声场中的变化规律、影响因素以及两者之间的对应关系。仿真结果表明，采用近场声全息计算换能器近场区域的声压分布，能够准确地反映圆形活塞在近场空间的声辐射规律，对换能器参数的确定提供了依据。 针对换能器在近场区域内无法对缺陷进行准确定位定量的问题，研究了近场超声波与内部微小缺陷的耦合声场特性。根据工件几何结构，建立了基于角谱理论的迭代算法模型，得到了超声波与工件内部微缺陷耦合后的声压分布。从波数领域研究微机械结构的声振问题，给出了金属薄板在集中力作用下的振动速度响应解析表达式，实现了基于角谱理论的有限声源辐射场的可视化表达。对含有微缺陷的铝合金薄板进行了有限元仿真，得出近场超声波与缺陷耦合后的工件表面动态声场变化规律，为金属薄板内部缺陷检测提供了理论依据。 融合光学全息显微镜的高横向分辨率与全场检测能力，以及近场声学技术的穿透能力和不受衍射极限理论限制的高分辨率，提出一种超声-激光全息的微机械结构表面声场检测方法。研究了脉冲激光数字全息检测原理，构建了微机械结构超声-激光全息检测系统。在近场超声纵波的激励下，采用数字全息子系统捕获到工件表面动态声场的瞬态全息图，并计算得到了微机械结构表面声场的相位与幅值，以此来判断微机械结构内部是否存在缺陷。 通过一系列理论分析与仿真计算，揭示了近场超声波在微机械结构中的传播机制。实验结果验证了超声-激光全息复合检测方法能够判断微机械结构中近场区域内是否存在微小缺陷。本文提出的检测方法具有较高的分辨率，突破了传统超声无损检测的衍射极限对分辨率的限制，实现了近场超声对微机械结构内部缺陷的检测。

A series of microelectromechanical structures, such as micromechanical components and microelectronic packaging, are developing in the direction of high density and high integration. The higher requirements for the quality control of microelectromechanical structures are put forward. Aiming at the problem of internal defect detection in micromachined structures, an ultrasonic laser holographic nondestructive testing method is proposed. In this paper, based on the theory of near field acoustics, the propagation mechanism of near field ultrasonic in micromechanical structure is studied in order to improve the accuracy and reliability of internal defect detection in micromechanical structure. In view of the stability and reliability of the sound field reconstruction process based on the normal particle, the noise characteristics in the wave number domain are studied and analyzed. An improved denoising method based on the filter function of the wave number domain is proposed. Through the numerical simulation example based on point source excitation, it is proved that the method can improve the reconstruction effect based on the Green function of k-space. The method improves the noise interference ability of the near-field acoustic holography reconstruction algorithm. In view of the fact that the traditional Rayleigh integral can not describe the acoustic distribution of circular piston near field, the near-field acoustic characteristics of transducers based on space Fourier transform are studied. The relationship between the sound field distribution of different wave numbers and the size of the sound source, the frequency of radiation and the measurement distance is analyzed and compared, The variation of the propagation and evanescent waves in the space sound field, between the influencing factors and the corresponding relation are obtained. The simulation results show that the sound pressure distribution in the near field region of the transducer by near field acoustic holography can accurately reflect the sound radiation law of the circular piston in the near field. The simulation provides the basis for the determination of the parameters of the transducer. Aiming at the problem that transducer can not accurately locate and quantify defects in the near field area, the coupling sound field characteristics of the near-field ultrasonic and the small internal defects are studied. According to the geometrical structure of workpiece, an iterative algorithm model based on angular spectrum method is established, and the sound pressure distribution after ultrasonic coupling with micro defect of workpiece is obtained. From the field of wave numbers, the acoustic vibration of a micromechanical structure is studied. The analytical expression of the vibration velocity response of a metal sheet under the action of the concentrated force is given. The visual expression of the radiation field of a finite source based on the theory of angular spectrum is realized. Finite element simulation of aluminum alloy sheet with micro defects is carried out. The change rule of the dynamic sound field of the workpiece surface after the coupling of the near-field ultrasonic wave and the defect is obtained, which provides the theoretical basis for the internal defect detection of the metal sheet. Combining the high transverse resolution and full field detection ability of the optical holographic microscope, the penetration ability of the near-field acoustic technology and the high resolution limited by the diffraction limit theory, a method of ultrasonic laser holography is proposed to detect the surface sound field of the micromechanical structure. The principle of pulsed laser digital holography is studied, and the ultrasonic laser holographic detection system for micro mechanical structure is constructed. Under the excitation of the near-field ultrasonic longitudinal wave, the transient hologram of the dynamic sound field on the workpiece surface is captured by the digital holography. The phase and amplitude of the surface sound field of the micromechanical structure is calculated, which aims to judge whether there are defects in the micromechanical structure. Through a series of theoretical analysis and simulation calculation, the propagation mechanism of near-field ultrasound in micromechanical structure is revealed. The experimental results verify that the ultrasonic laser holographic composite detection method can judge whether there are tiny defects in the near-field region of the micromechanical structure. The detection method proposed in this paper has higher resolution, which breaks through the limitation of the diffraction limit of the traditional ultrasonic nondestructive testing, and the near-field ultrasonic detection of internal defects in micromachined structures is realized.