Research On Microspectrometer Based On Cholesteric Liquid Crystal Microcapsule

Spectral analysis technology is widely used in scientific research,industrial production,material science and other fields.Traditional desktop spectrum systems usually have a huge volume,mainly used for laboratory spectral analysis.The miniaturization of the spectrometer can broaden its application field,have huge academic and industrial value.Currently,many miniature spectrometer systems have been commercialized,In the future,the microspectrometer can be combined with artificial intelligence,smartphones to achieve many emerging applications.In this paper,a novel microspectrometer based on cholesteric liquid crystal microcapsule(CLCM)is designed and prepared.This microspectrometer mainly uses CLCM as an adjustable filter to replace the grating in the traditional spectrometer to achieve spectral splitting.At the same time,we use laserinduced graphene(LIG)as the substrate,through temperature control,electronic control and other means,change the reflection filtering characteristics of CLCM,so as to get different reflection image information,establish the spectral response database under different light sources.We analyze and process the image information of CLCM under the unknown light source,the spectral curve of the unknown light source is "reconstructed".The main research content of this paper includes the following four parts:1、We use the COMSOL Multiphysics software to study the optical characteristics of cholesteric liquid crystal(CLC),explore the effects of pitch,incident light,and liquid crystal layer thickness on the CLC reflection spectrum.Then we use the software to study the characteristics of LIG thermodynamics,discuss the effects of laser power,scanning speed,and spot radius on the distribution of PI section temperature field and phase change process.2、We build a micro-temperature test platform based on CLCM,and the samples are designed and prepared.Meanwhile,the color of the CLCM is quantified,the reflection characteristics of CLCM are studied,and the thermochromic characteristics of CLCM are explored.It is proved that the Hue value and temperature of a single CLCM or multiple CLCMs show a positive correlation.3、We measure the DC conductivity of LIG samples under different laser parameters by four probe method.According to the experimental data,the conductivity of LIG is negatively correlated with the laser scanning speed and positively correlated with the laser power.Then,the electrothermal characteristics of Li G-based CLCMs are studied in this paper,and it is proved that the Hue value and the applied voltage intensity show a positive correlation between a single CLCM or multiple CLCMs.4、We use the HSI model as the basic principle and use MATLAB for image processing,then we study the correspondence between lighting sources and color values of CLCM,mainly including the correspondence between light source bands and the Hue value of CLCM,as well as the correspondence between light source intensity and the intensity value of CLCM.Based on the above correspondence,examples of narrow band and wide band spectrum reconstruction are carried out respectively to verify the feasibility of the microspectrometer.