With the development of science and technology, research in microelectronics, materials science, precision mechanics, life sciences and biology has penetrated into the atomic field. In order to adapt to this development, there is an urgent need for a nanometer and sub-nanometer precision measurement system with quantitative significance. Therefore, since the 1980s, a new discipline, nanometer metrology, has gradually been born. In 1982, the German physicist Binnich of the IBM Zurich Research Laboratory and the Swiss physicist Lorell designed the world's first scanning tunneling microscope (STM) and won the Nobel Prize in Physics in 1986. The principle of STM utilizes physics tunneling and tunneling current. It uses a very thin probe (the tip of the needle is a single atom) to approach the surface of the test piece and applies a bias between the probe and the test piece. When approaching the nanoscale distance, a tunnel current is generated, the magnitude of which is inversely proportional to the distance. STM has two application methods in metering: one is to maintain the tunnel current by feedback to determine the surface topography of the test piece; the other is to measure the tunnel current to characterize the probe and the test piece. distance. Following the scanning tunneling microscope, a series of detection techniques and instruments with atomic scales such as atomic force microscopy (AFM), scanning near-field optical microscopy (SNOM), and photon scanning tunneling microscopy (PSTM) have appeared. The application of these advanced technologies has enabled humans to observe the arrangement of individual atoms on the surface of matter for the first time in history and successfully realize atomic relocation. However, these instruments simply "observe" the internal structure of the molecule, without the concept of quantity. In the practical application of metrology, it is also necessary to solve the problem of traceability and establish measurement standards, that is, to provide a traceable length measurement method with nanometer accuracy. Since the 1990s, scientists from various countries have conducted a lot of research on this. The China Institute of Metrology and the German PDB have developed an atomic force microscope and a beat FB interferometer that can self-calibrate and achieve absolute measurement, solving the problem of traceability and measurement of single-dimensional dimensions. In 1994, NIST developed the first Molecular Measuring Machine. It is actually an ultra-high precision coordinate measuring machine with a measuring range of 50mm×50mm×12mm and a spatial measurement uncertainty of 1nm. The measuring machine adopts a traceable ultra-high resolution heterodyne laser interferometer as the measuring system. The interferometer uses optical 8 times frequency and phase 100 subdivision to achieve a resolution of 0.075 nm. The probes of the molecular measuring machine are divided into two types. : Confocal optical microscopy for low resolution measurements; tunnel or atomic force microscopy for high resolution measurements. The molecular measuring machine not only solves the problem of metering traceability, but also realizes the true meaning of nanometer measurement, and can operate a cluster of molecules and atoms (or even a single atom), which can be applied to the technical fields of micromachines, nanotubes, nanomaterial processing, etc. An important tool that is indispensable for scientific research and application. Polyester Mat,Pet Needled Mat,Pet Anti-Static Needled Mat Welding machine, Co., Ltd. , http://www.sdgeomaterial.com