High-accuracy high-spatial resolution long range profile detection system

Abstract

The invention discloses a high-accuracy high-spatial resolution long range profile detection system, which comprises a workbench, a transmission platform, a laser light source, a scanning optical head, a beam splitting prism and a signal acquisition processing unit, wherein the scanning optical head is arranged on the transmission platform; the beam splitting prism is used for deflecting light output from the laser light source for incidence into the scanning optical head, and an incident direction is consistent with the scanning direction of the transmission platform; the scanning optical head is used for deflecting and focusing incident light beams to the surface of an object to be detected in a detection area, for the object to be detected, of the workbench; and light reflected by the surface of the object to be detected in the detection area for the object to be detected sequentially passes through the scanning optical head and the beam splitting prism, and enters the signal acquisition processing unit. The system can be used for the high-spatial frequency sampling measurement of the surface to be detected, and the measurement accuracy is high; and the system can be used for measuring a large-sized object, and is particularly suitable for the detection of an optical element on a synchrotron radiation beam.

Description

technical field [0001] The invention relates to the surface shape detection of large-scale mirror objects, in particular to a high-space resolution and high-precision long-distance surface shape detection system. Background technique [0002] The surface error of the optical element surface has a very important impact on the performance of the optical system. According to the distribution of the spatial frequency of the surface error, it can be divided into high spatial frequency, medium spatial frequency and low spatial frequency error. The existing research results show that different frequency errors have different effects on the imaging system. For example, the refraction effect of high-frequency errors and the scattering effect of low-frequency errors will not significantly change the shape of the point spread function on the image plane, but will only cause the focus energy to change. Divergence, reduction of imaged contrast and signal-to-noise ratio, in contrast, the ...

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Problems solved by technology

However, there are generally the following problems: (1) Due to the flaws of the optical components in LTP, which greatly limit the performance of LTP, the best LTP accuracy in the world (only 0.2 microrad) still cannot reach nanometer Focusing requirements cannot fully reflect the focusing performance of the optical components to be tested (references: Rommeveaux, A., L. Assoufid, et al. (2007). Second metrology round-robin of APS, ESRF and SPring-8 laboratories of elliptical and spherical hard-x-ray mirrors, San Diego, CA, USA, SPIE.p.2278-2280(1995); Qian, S. and K. Qian(2010).Study and considerations of nanometer and nano-radian surface profiler , SPIE, P.O.BOX 10 Bellingham WA 98227-0010 USA.); (2) and the highest measurable surface shape error spatial frequency is 1 line per millimeter (line per millimeter), which can reflect very little information on surface shape errors; (3) During the scanning process of the optical head, the rotation error of the air-bearing transmission table is very large, the order of magnitude is several microradians. Although the reference mirror can be used to compensate for this error, this increases the complexity of the system structure and calculation

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