【摘要】：在薄膜生產(chǎn)和加工中,實(shí)現(xiàn)對(duì)薄膜厚度在線精確測(cè)量,對(duì)控制薄膜產(chǎn)品的精度和降低成本,有著非常重要的意義。本文通過一種基于紅外線的薄膜厚度測(cè)量技術(shù),實(shí)現(xiàn)對(duì)薄膜厚度實(shí)時(shí)在線的測(cè)量。本文主要研究使用紅外技術(shù)實(shí)現(xiàn)對(duì)薄膜厚度測(cè)量的原理,并在此原理基礎(chǔ)上設(shè)計(jì)了以DSP為核心處理器的紅外薄膜厚度在線測(cè)量系統(tǒng)。該系統(tǒng)主要包括紅外信號(hào)發(fā)生電路、紅外信號(hào)接收電路、模擬信號(hào)處理電路、數(shù)字信號(hào)核心處理器TMS320F2812以及人機(jī)交互界面。實(shí)現(xiàn)紅外信號(hào)驅(qū)動(dòng)、光電轉(zhuǎn)換、模擬信號(hào)處理、AD采樣、數(shù)字信號(hào)處理、數(shù)據(jù)的實(shí)時(shí)顯示和人機(jī)交互等功能。本系統(tǒng)基于原理,即利用透射光光強(qiáng)衰減程度和薄膜厚度之間滿足該定理,通過最終測(cè)量透射光光強(qiáng)所對(duì)應(yīng)的電信號(hào)實(shí)現(xiàn)對(duì)薄膜厚度的測(cè)量。為了盡量避免干擾,該在線測(cè)量系統(tǒng)加入了反饋裝置。本文介紹了薄膜厚度在線測(cè)量系統(tǒng)的實(shí)現(xiàn)過程,對(duì)在線系統(tǒng)的軟硬件部分分別進(jìn)行了分析、設(shè)計(jì)和調(diào)試。本系統(tǒng)以處理器TMS320F2812為核心,主要由光信號(hào)驅(qū)動(dòng)電路、紅外接收電路、模擬信號(hào)處理電路、AD采樣和處理電路、人機(jī)交互四個(gè)部分組成。本文使用AVR單片機(jī)配合LM317穩(wěn)壓器來產(chǎn)生2.0k Hz的方波,驅(qū)動(dòng)紅外發(fā)光管產(chǎn)生3.4um紅外測(cè)量光;使用以Pbse紅外光敏電阻為核心構(gòu)成的紅外接收電路獲取紅外透射光信號(hào),經(jīng)過光電轉(zhuǎn)換轉(zhuǎn)換成電信號(hào),電信號(hào)經(jīng)過前置信號(hào)處理和放大后,引入到模擬濾波芯片MAX275設(shè)計(jì)的標(biāo)準(zhǔn)帶通濾波器中,最終得到信噪比較高的模擬信號(hào);采用16位8通道AD7606對(duì)模擬信號(hào)和紅外接收電路溫漂信號(hào)進(jìn)行信號(hào)采樣,DSP核心處理器F2812使用FIR數(shù)字濾波器進(jìn)行數(shù)字濾波,并將紅外接收電路溫漂信號(hào)作為反饋信號(hào)引入到數(shù)據(jù)計(jì)算中,利用原理,得到薄膜厚度與光強(qiáng)度關(guān)系;DSP核心處理器F2812和液晶顯示觸摸屏經(jīng)過程序設(shè)計(jì)和通信設(shè)置,實(shí)現(xiàn)人機(jī)交互功能。本系統(tǒng)應(yīng)用CCS軟件開發(fā)平臺(tái)結(jié)合MATLAB中的濾波工具,實(shí)現(xiàn)對(duì)系統(tǒng)軟件部分的編程,調(diào)試以及仿真。實(shí)驗(yàn)結(jié)果表明,本系統(tǒng)能夠排除干擾,在測(cè)量量程內(nèi)實(shí)現(xiàn)精度控制在5%以內(nèi)的指標(biāo)要求,實(shí)現(xiàn)對(duì)薄膜厚度進(jìn)行實(shí)時(shí)在線準(zhǔn)確測(cè)量。
[Abstract]:In the production and processing of thin films, it is of great significance to realize the on-line accurate measurement of film thickness and to control the precision and reduce the cost of film products. In this paper, a kind of infrared film thickness measurement technology is used to measure the film thickness in real time. In this paper, the principle of infrared thin film thickness measurement using infrared technology is studied. Based on this principle, an infrared film thickness measurement system based on DSP core processor is designed. The system mainly includes infrared signal generating circuit, infrared signal receiving circuit, analog signal processing circuit, digital signal core processor TMS320F2812 and man-machine interface. The functions of infrared signal driving, photoelectric conversion, analog signal processing, AD sampling, digital signal processing, real-time display of data and man-machine interaction are realized. The system is based on the principle that the attenuation degree of transmitted light intensity and the thickness of the film satisfy the theorem, and the thickness of the film can be measured by the electrical signal corresponding to the final measurement of the intensity of the transmitted light. In order to avoid interference as far as possible, a feedback device is added to the online measurement system. This paper introduces the realization process of the film thickness online measurement system, and analyzes, designs and debugs the software and hardware parts of the online system. The system is composed of four parts: optical signal driving circuit, infrared receiving circuit, analog signal processing circuit, AD sampling and processing circuit and man-machine interaction. In this paper, AVR single-chip microcomputer and LM317 regulator are used to generate 2.0 k Hz square wave, and the infrared luminous tube is driven to generate 3.4um infrared measurement light. Infrared receiving circuit composed of Pbse infrared photosensitive resistor is used to obtain infrared transmission light signal, which is converted into electric signal by photoelectric conversion, and the signal is processed and amplified by pre-signal. The analog signal with high SNR is obtained by introducing it into the standard bandpass filter designed by analog filter chip MAX275. The 16 bit 8 channel AD7606 is used to sample the analog signal and the temperature drift signal of the infrared receiving circuit. The core processor F2812 of DSP is digitally filtered by FIR digital filter. The temperature drift signal of the infrared receiving circuit is introduced into the data calculation as the feedback signal and the relationship between the film thickness and the light intensity is obtained by using the principle. DSP core processor F2812 and LCD touch screen are programmed and set up to realize man-machine interaction. This system uses CCS software development platform and the filter tool in MATLAB to realize the programming, debugging and simulation of the software part of the system. The experimental results show that the system can eliminate interference, achieve the requirement of accuracy within 5% of the measurement range, and realize the real-time and accurate measurement of film thickness.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TN219;TP274

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本文編號(hào)：2423452