| Since the 1990 s, compared with cooled infrared detector,uncooled infrared detectors have the advantages such as no refrigeration, low cost, low power consumption, light weight, compact and easy to use. Therefore uncooled infrared detectors quickly attracted national attention and became the frontier research of modern infrared technology. Uncooled infrared detector has been a research focus of many countries.In this dissertation, a readout integrated circuit(ROIC) with adaptive, low noise, high uniformity and integrity has been described for the uncooled micro-bolometer. Substrate temperature induced error compensation, non-uniformity correction,ADC and temperature sensor circuit have been integrated on the ROIC chip. A 640 × 512 experimental uncooled micro-bolometer focal plane array(FPA) has been designed and implemented on silicon without TEC(thermoelectric cooler) ROIC. The main results are as follows:1. A generic circuit model based on the thermal and electrical properties of micro-bolometer has been developed. This model can be used to simulate the optical, thermal and electrical performance of micro-bolometer such as thermal capacity, thermal conductivity, bias voltage, temperature coefficient of resistance(TCR), temperature rise and responsivity. The noise performance based on micro-bolometer and a capacitor feedback transimpedance amplifier(CTIA) has been discussed, and also including the effects of noise, responsivity and noise equivalent temperature difference(NETD) for bias voltage, integrate time and integrate capacity. Based on the discussion above, to improve the performance of the system, improve the bias voltage is more effective than the increasing integration time.2. The design of ROIC. The ROIC includes five modules: adaptive bridge bias circuit, integral and sampling circuit, digital-to-analog converter(DAC), analog-to-digital converter(ADC) and CMOS temperature sensor circuits.(1) A substrate temperature compensation resistor has been introduced for adaptive bridge bias circuit allowing micro-bolometers to operate without TEC. The measurement data shows that the maximum difference of the output voltages is only 261 mV over 80 K substrate temperature change.(2) Two shared capacitances have been used for integral and sampling allowing ROIC to operate with high frame rate.(3) The output voltage of DAC is used to adjust the bias on each pixel. All DAC share a resister string, and only decoders are integrated to ROIC channel. This technique is used to realize low power consumption and compact for ROIC. Measurements show the 6bits DAC enables the non-uniformity reduces to 13%.(4) The column level integration single-slope ADC can be used to improve anti-interference effectively. According to the test results,the INL is ±1.2LSB and DNL is ±0.7LSB, and the noise performance is reduced effectively.(5) An on chip temperature sensor is designed to replace the conventional temperature sensor, resulting in improvement of the output signal performance. According to the experimental chip test results, the sensitivity is 22.8mV/K,and the linearity performance of the on chip temperature sensor is 99.95%.3. A 640×512 micro-bolometer array is fabricated onto the ROIC using a special Micro-machine process.According to the ROIC test results, the temporal RMS noise voltage is 199.7 μV and the fixed pattern noise is 3.6mV. After vacuum package,measurement and calculation results of the monolithic uncooled micro-bolometer FPA show that the responsivity of 2.97mV/K and the temporal RMS noise voltage of 210 μV have been obtained.Analysis shows that the effect of bias voltage and the integration time on NETD. The imaging effect is very good at different substrate temperature.
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