- 學位論文
葉綠素含量讀出系統與晶片化實現
The Readout System of Chlorophyll Contents and Chip-Integration
摘要
本論文利用光學感測方式進行葉綠素含量的量測，葉綠素又與植物生長狀況有很大的相關性，所以透過葉綠素對光波長有不同的吸收特性以及比爾朗伯定律計算出其葉綠素含量，利用660nm強烈吸收特性反映出其葉綠素含量再透過940nm的極差吸收特性去反映出量測時的誤差，這些值都可藉由量測光二極體的光電流改變量得知，運用雙光源發光二極體、光二極體、轉阻放大器、類比數位轉換器、MCU即可完成葉綠素含量讀出系統與商用儀器相比可有效地減少近80%的成本，並且利用ZigBee網路進行無線傳輸。 透過TSMC 0.35um process將轉阻放大器以及類比數位轉換器和並列轉串列電路整合成一葉綠素含量讀出晶片，如此可有效地縮小全系統面積以及功耗，在桂花樹葉片的量測中本系統葉綠素含量的量測值與葉綠素實際含量相關係數可達0.72其誤差為±3個SPAD，而讀出晶片的光電流感測範圍可從0至50uA，整體面積為1.46×1.46 mm2，操作頻率為50K Hz。
並列摘要
The study aims to develop a device that measures the chlorophyll content in a leaf using the optical sensing method. Chlorophyll has great relationship in plant growth conditions. Because Chlorophyll has different absorption characteristics for light wavelength, so we using the idea of Beer Lambert Law which relates the absorption of light to the properties of the material through which the light is travelling, so that chlorophyll content can be determine. Utilizing the strong absorption characteristic of 660nm light wavelength to determine the chlorophyll content and then compare it with the absorption characteristic under 940nm wavelength to determine the measurement error, this can be done by determining the change in current of the photodiode. Light emitting diode, photodiode, transimpedance amplifier, ADC,and microcontroller unit can be used to complete the read-out circuit for chlorophyll content which is better and 80% cheaper than the ones in the market and using ZigBee to transmission. To Combine the transimpedance amplifier , ADC , and Parallel to Serial Circuit by using TSMC 0.35µm technology can effectively reduce the area and power consumption of the system. Using the proposed system to measure the chlorophyll content of Osmanthus leaves the correlation coefficient can reach 0.72 and the inaccuracy is ± 3 SPAD and Chip area is 1.46×1.46 mm2 sample rate is 50K Hz and current range is 0~ 50µA.