Device and method for measuring refractive index of plane equal-thickness medium

Abstract

The embodiment of the invention discloses a device and a method for measuring the refractive index of a plane equal-thickness medium, the measuring device comprises a spectrum confocal sensor, a spectrometer and a distance adjusting mechanism, the spectrum confocal sensor comprises a white light spot light source, a semi-transparent semi-reflecting mirror and a dispersion objective lens; the semi-transparent semi-reflecting mirror and the dispersion objective lens are sequentially arranged between the white light spot light source and the measured medium along the optical axis; the distance adjusting mechanism drives the spectrum confocal sensor and the measured medium to be close to each other or far away from each other, so that the distance between the dispersion objective lens and the measured medium is changed for three times along an optical axis; the spectrometer is opposite to the reflecting surface of the semi-transparent semi-reflecting mirror and is used for detecting the wavelengths of the upper surface and the lower surface which are focused and reflected on the detected medium; and the refractive index curve of the measured medium is calculated according to the four different wavelengths obtained through detection. According to the invention, the method 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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