Device and method for measuring refractive index of flat plate type transparent medium

Abstract

A device for measuring the refractive index of a flat plate type transparent medium comprises a cassette, a frosted glass screen, a thin frosted glass screen, a CCD (charge coupled device) camera, a precision translation stage and a platform lining plate. The platform lining plate is arranged in the cassette, a semiconductor laser device, the frosted glass screen, a converging lens and the precision translation stage are mounted on the platform lining plate, the thin frosted glass screen and the CCD camera are mounted on the precision translation stage and synchronously move along with the precision translation stage, the semiconductor laser device, the frosted glass screen, the converging lens, the thin frosted glass screen and the CCD camera are sequentially and coaxially arranged in the cassette, and a shading cover is arranged on the cassette. A method for measuring the refractive index of the flat plate type transparent medium by the aid of the device includes that the flat plate type medium to be measured is placed between the converging lens and the precision translation stage, the diameter of a circular light spot on the thin frosted glass screen can be changed before and after the medium to be tested is placed between the converging lens and the precision translation stage, the refractive index of the medium can be obtained on the basis of calibration if only the diameter of the light spot is known after the medium to be measured is placed between the converging lens and the precision translation stage, and corresponding images of the circular light spot are acquired and measured by the computer in real time via the CCD camera. The method is applicable to measuring refractive indexes of solid and liquid media, operation is simple and convenient, measured data are fewer, a measurement range is unlimited, and the method and the device can be used for monitoring the refractive indexes in real time.

Description

technical field [0001] The invention relates to the measurement of the refractive index of solid and liquid, in particular to the measurement of the refractive index of a flat transparent medium with two parallel surfaces. Background technique [0002] Refractive index is an important optical parameter of the medium, and also an important performance index of some related industrial and agricultural products. It is widely used in optical materials, food, chemical industry, medicine and other fields. [0003] At present, there are many methods for measuring the refractive index of a medium. For a medium with two parallel surfaces, geometric optics and interferometry are commonly used. For example, the Abbe refractometer is used, but its disadvantage is that it is only applicable to the measurement of the refractive index in a specific range; there is a method of measuring the refractive index based on the lateral offset generated by the beam passing through the medium, and th...

AI Technical Summary

Problems solved by technology

For example, the Abbe refractometer is used, but its disadvantage is that it is only suitable for the measurement of the refractive index in a specific range; there is a method of measuring the refractive index based on the lateral offset generated by the beam passing through the medium, and then using a linear array CCD or PSD sensor to detect the offset. The disadvantage is that it is necessary to determine the incident angle of the beam, and adjust the linear array CCD or PSD sensor to be perpendicular to the outgoing light, and the operation is relatively difficult; there are also measurements using the interferometric method. High, cumbersome to operate

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