Large numerical aperture microscopic objective lens wave aberration measurement system and measurement method

Abstract

The invention discloses a measurement system and a measurement method for a wave aberration of a large numerical aperture microscope objective. The system comprises a laser, a collimating and beam expanding system, a neutral filter, rotating frosted glass, a first beam splitter, a second beam splitter, a wavefront sensor, a collecting lens, a diaphragms, a photomultiplier tube, a calibration planemirror and a cover slip. The invention discloses a non-coherent method for measuring the wave aberration of the microscope objective. The measurement system and the measurement method for the wave aberration of the large numerical aperture microscope objective can be applied to measurement for the wave aberration of any large numerical aperture (oil immersion / non-immersion oil) microscope objective; by using the characteristics that the incident parallel beam diameter is larger than an exit pupil of the microscope objective, the measurement for the wave aberration of any large numerical aperture microscope objective can be guaranteed. Since the non-coherent measurement mode is adopted, the influence of spurious fringes can be reduced; through the precise focusing function, the measured wave aberration is guaranteed to be not influenced by a defocusing factor; and meanwhile, by use of the own reflection of the cover slip, the measured wave aberration is consistent with the microscope objective design and the actual use state, and the accurate measurement of the microscope objective lens can be implemented.

Description

technical field [0001] The invention relates to the technical field of optical measurement, in particular to a large numerical aperture microscopic objective lens wave aberration measurement system and measurement method. Background technique [0002] With the rapid development of science and technology, the application fields of microscopes are becoming wider and wider. In addition to traditional teaching, scientific research, medical and industrial applications, there are new applications in the fields of microelectronics manufacturing, new material research and development, life science research and new drug development. The 2014 Nobel Prize in Chemistry was awarded to three scientists, including American scientists Eric Betzig, William Mona and German scientist Stefan Hell, in recognition of their contributions to the development of super-resolution fluorescence microscopy. The issuance of the award has further promoted the rapid development of microscopic technology to...

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Problems solved by technology

In addition, this method is also difficult to find conjugate points, and the operation is complicated

[0004] The third method is to use a flat mirror to reflect the measuring beam back. This method is different from the real wave aberration of a microscope with a cover glass, and it is not easy to determine the focal plane of the microscope objective lens.

The fourth method requires a reference microscope objective lens. The numerical aperture of the reference microscope objective lens must be greater than the numerical aperture of the measured microscope objective lens. There are two measurement methods. One defaults that the wave aberration of the reference microscope objective lens is zero. The result is the wave aberration of the microscopic objective lens to be tested. Generally, a standard microscopic objective lens is used as a reference objective lens. The second method is to compare and measure the three microscopic objective lenses rotated 180 degrees to obtain the wave aberration of the microscopic objective lens to be tested. , this method has high requirements for rotation accuracy, and the conjugate points of the two measurement methods are not easy to find

[0005] The above four methods are all based on interference, the core of which is the Tieman Green interferometer, which obtains the wave aberration of the microscopic objective lens through the interference fringes of the measuring beam and the reference beam. Since the microscopic objective lens itself contains multiple sets of lenses, except In addition to the main interference fringes, there are some stray light fringes, which also affect the measurement results

[0006] There are three domestic patents for the measurement of wave aberration of microscopic objective lenses: one is "a large numerical aperture objective lens wave aberration detection device and method" (Patent No. "Objective Lens Wave Aberration Detection System" (Patent No. 201310246734.3) applied by Zhang Yunhai, Suzhou Institute of Medical Engineering, Chinese Academy of Sciences, "Large Numerical Aperture Oil Immersion Lens Wave Aberration Detection Device" (Patent No. 201720366532.6) of Nanjing Donglilai Company, the first The Hartmann sensor method is adopted, the optical path adopts the transmissive optical path, and the light emitted by the diffuser plate is regarded as a beam of standard spherical waves. The biggest defect of the modified method is the limited numerical aperture measurement. At present, the maximum emission aperture of the diffuser plate at home and abroad is 0.8. Moreover, it cannot be immersed in oil and cannot be placed with a cover glass, so only dry mirrors with a numerical aperture below 0.8 and no cover glass can be measured

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