A measuring device and measuring method for the refractive index of a plane equal-thickness medium

Abstract

The embodiment of the present application discloses a measuring device and method for measuring the refractive index of a plane equal-thickness medium. The measuring device includes a spectral confocal sensor, a spectrometer, and a distance adjustment mechanism. The spectral confocal sensor includes a white light point light source, a semi-transparent reflective mirror and dispersion objective lens; the half-transparent half-mirror and dispersion objective lens are sequentially arranged along the optical axis between the white light point light source and the measured medium; the distance adjustment mechanism drives both the spectral confocal sensor and the measured medium close to or far away from each other so that the distance between the dispersive objective lens and the measured medium changes 3 times along the optical axis; The wavelengths of the upper and lower surfaces reflected back; the refractive index curve of the measured medium is calculated according to the detected 4 different wavelengths. According to the invention, it has the advantages of high detection efficiency and small error.

Description

technical field [0001] The invention relates to the field of measuring the refractive index of transparent materials, in particular to a measuring device and a measuring method for the refractive index of a plane equal-thickness medium. Background technique [0002] The refractive index is one of the basic parameters of optical materials. The refractive index of the medium decreases with the increase of the wavelength of the incident light. The difference of the refractive index of different wavelengths is called dispersion. The research on the refractive index and dispersion of the medium is of great significance to understand the properties of the medium material, and it is also an essential parameter in the design of the optical system, and its size directly affects the imaging quality of the system. Accurately obtaining the refractive index values ​​of optical materials in the visible and near-infrared bands is very important for the production, use and optical design of...

AI Technical Summary

Problems solved by technology

However, these methods require complex operations, and some methods require the material to be processed into specific shapes and sizes

If you want to further obtain the refractive index curve and dispersion data of flat and thick media such as flat glass and flat crystal, you need to use the Schott formula or Sellmeier formula for fitting. These commonly used refractive index fitting formulas usually require at least 10 or more More accurate refractive index curves can be obtained only when the wavelength refractive index data is available, so the current refractive index measurement method takes a lot of time

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