In this paper, the characteristics of polymeric packaging materials for Pre-mold QFN type cmos image sensor (CIS) have been carefully investigated. Hygro-mechanical property, the coefficient of moisture expansion (CME...
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In this paper, the characteristics of polymeric packaging materials for Pre-mold QFN type cmos image sensor (CIS) have been carefully investigated. Hygro-mechanical property, the coefficient of moisture expansion (CME) for different materials was measured through Thermal Mechanical Analysis (TMA) and Thermal Gravitational analysis (TGA) at given humidity and temperature. Moisture absorption/desorption diffusivity were determined under Arrhenius behavior. The transient moisture diffusion analysis described by Fick's equation is performed to evaluate the overall moisture distribution. In accordance with the JEDEC pre-conditioning standard JESD22-A120, reliability and thermal design were carried out due to mismatch of the coefficient of thermal expansion (CTE) and CME for multi-material package of CIS. A three-dimensional solid model of CIS based on finite element ANSYS software is developed to predict the thermal-induced strain, hygroscopic swelling deformation and the residual thermo-hygro-mechanical stress distributions. A series of comprehensive parametric studies were conducted in this research.
This paper proposes and demonstrates a polarization-analyzing cmossensor based on imagesensor architecture. The sensor was designed targeting applications for chiral analysis in a microchemistry system. The sensor f...
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This paper proposes and demonstrates a polarization-analyzing cmossensor based on imagesensor architecture. The sensor was designed targeting applications for chiral analysis in a microchemistry system. The sensor features a monolithically embedded polarizer. Embedded polarizers with different angles were implemented to realize a real-time absolute measurement of the incident polarization angle. Although the pixel-level performance was confirmed to be limited, estimation schemes based on the variation of the polarizer angle provided a promising performance for real-time polarization measurements. An estimation scheme using 180 pixels in a 1 degrees step provided an estimation accuracy of 0.04 degrees. Polarimetric measurements of chiral solutions were also successfully performed to demonstrate the applicability of the sensor to optical chiral analysis.
Many mixed-signal circuits are nonlinear time-varying systems whose noise estimation cannot be obtained from the conventional frequency domain noise simulation (FNS). Although the transient noise simulation (TINS) sup...
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Many mixed-signal circuits are nonlinear time-varying systems whose noise estimation cannot be obtained from the conventional frequency domain noise simulation (FNS). Although the transient noise simulation (TINS) supported by a commercial simulator takes into account nonlinear time-varying characteristics of the circuit, its simulation time is unacceptably long to obtain meaningful noise estimation results. Since the single-slope analog-to-digital converter with correlated double sampling (CDS/SS-ADC) in a cmos image sensor (CIS) is composed of several operation phases in which the circuit topologies are different from each other, the noise cannot be estimated by the conventional FNS. This paper presents a noise estimation method for the CDS/SS-ADC that uses the FNS results while the transient noise behavior is taken into account. The proposed method provides noise estimation results closer to that of the TNS than the conventional FNS, whereas the simulation time is about the same as that of the FNS.
This paper presents a 14-bit Incremental Sigma-Delta (Sigma Delta) analog-to-digital converter suitable for column wise integration in a cmos image sensor. A two step conversion is performed to improve the conversion ...
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This paper presents a 14-bit Incremental Sigma-Delta (Sigma Delta) analog-to-digital converter suitable for column wise integration in a cmos image sensor. A two step conversion is performed to improve the conversion speed. As the same Sigma Delta modulator is used for both steps, the overall complexity is reduced. Furthermore, the use of inverter-based amplifiers instead of operational transconductance amplifier facilitates the integration within the column pitch and decreases power consumption. MonteCarlo simulations have been done in order to validate the design of the inverter. The proposed ADC is designed in 0.18 mu m cmos technology. The simulation is performed with a 1.8 V voltage supply, a 20 MHz system clock frequency and an oversampling ratio (OSR) of 70, and achieves a power consumption is 460 mu W, a SNDR of 85.4 dB at a sampling rate of 250 kS/s.
This paper presents a cmos image sensor (CIS) with a zoom ADC, to quantize in-pixel temperature sensors, as well as for faster readout speed of the image pixels while maintaining low quantization noise. The proposed 1...
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This paper presents a cmos image sensor (CIS) with a zoom ADC, to quantize in-pixel temperature sensors, as well as for faster readout speed of the image pixels while maintaining low quantization noise. The proposed 15 bit zoom ADC has a 4 bit Unit Capacitor Array (UCA) SAR and a 13 bit incremental 2nd-order delta-sigma ADC (DSADC), as its first and second stage, respectively. The proposed UCA with improved switching and decoding technique minimizes capacitor area and switching energy, by 50 % and 75 %, respectively, compared to a conventional binary weight array (BWA) counterpart. Measurement results on 4 chips show the proposed zoom ADC could operate at least twice as fast, when maintaining the same signal-to-noise ratio (SNR), or improve its SNR by 9 dB, when maintaining its sampling speed, compared to a DSADC only alternative. The proposed 15 bit ADC is measured a SNR of 80.1 dB and INL and DNL within +/- 1.5 LSB and +/- 1 LSB (full scale voltage is 1 Vp-p), when operating at 31 kHz. The incorporated imager-based temperature sensors are measured to have inaccuracies within +/- 0.6 degrees C on 4 chips, between -20 and 80 degrees C, when quantized by the same zoom ADC.
This article presents a 50.1-Mpixel 14-bit 250-frames/s back-illuminated stacked cmos image sensor on 35-mm optical format exhibiting 1.18-e(-)rms random noise at 0 dB. This sensor employs a load reduction technique b...
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This article presents a 50.1-Mpixel 14-bit 250-frames/s back-illuminated stacked cmos image sensor on 35-mm optical format exhibiting 1.18-e(-)rms random noise at 0 dB. This sensor employs a load reduction technique by splitting half of pixel signal line using a Cu-Cu connection technology underneath the pixel area, pipelined operation with a gain-adaptive column-parallel kT/ C noise-canceling sample and hold, and a 250-frames/s scanning rate and 14-bit resolution delta-sigma analog-to-digital converter (ADC) circuit. Moreover, an on-chip online calibration of column mismatch maintains the non-linearity of the output image within -0.42%. As a result, FoM6 (e(-)* pJ/step) of 0.09 is obtained as the state-of-the-art performance.
We report on the optical properties of plasmonic hole arrays as they apply to requirements for plasmonic color filters designed for state-of-the-art Si cmos image sensors. The hole arrays are composed of hexagonally p...
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We report on the optical properties of plasmonic hole arrays as they apply to requirements for plasmonic color filters designed for state-of-the-art Si cmos image sensors. The hole arrays are composed of hexagonally packed subwavelength sized holes on a 150 nm Al film designed to operate at the primary colors of red, green, and blue. Hole array plasmonic filters show peak transmission in the 40-50% range for large (>5 X 5 mu m(2)) size filters and maintain their filtering function for pixel sizes as small as similar to 1 x 1 mu m(2), albeit at a cost in transmission efficiency. Hole array filters are found to robust with respect to spatial crosstalk between pixel within our detection limit and preserve their filtering function in arrays containing random defects. Analysis of hole array filter transmittance and crosstalk suggests that nearest neighbor hole-hole interactions rather than long-range interactions play the dominant role in the transmission properties of plasmonic hole array filters. We verify this via a simple nearest neighbor model that correctly predicts the hole array transmission efficiency as a function of the number of holes.
This paper presents a low-power always-on imagesensor for mobile and wearable device applications. The sensor continuously captures images for smart sensing, such as face detection, eye tracking, and gesture recognit...
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This paper presents a low-power always-on imagesensor for mobile and wearable device applications. The sensor continuously captures images for smart sensing, such as face detection, eye tracking, and gesture recognition, and it provides high-resolution images for capturing pictures with a unified sensor. The sensor employs a switchable dual mode: always-on (AO) mode with low power consumption and photo-shooting (PS) mode with high signal-to-noise ratio. For dual-mode operation with high energy efficiency, we implemented dynamic voltage scaling that provides 0.9 V analog-digital supply voltage for the AO mode and 3.3 V analog-1.8 V digital supply voltage for the PS mode. For low-voltage operation in the AO mode, a conventional four-transistor pixel operates as a charge-shared pixel. In order to suppress power consumption and frequency in conventional single-slope analog-to-digital converters (ADC), two neighboring column-parallel ADCs are reconfigured to one successive-approximation ADC for low-voltage and low-frequency operation in the AO mode with negligible area overhead. The fabricated 640 x 480 pixel prototype sensor operates at 45.5 mu W (at 15 fps, 320 x 240) in the AO mode, which significantly extends battery life when performing always-on sensing.
This paper presents a non-invasive, non-contact system for the measurement of the arterial dorsum manus vibration waveforms of Parkinson disease patients. The laser line method is applied to detect the dorsum manus vi...
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This paper presents a non-invasive, non-contact system for the measurement of the arterial dorsum manus vibration waveforms of Parkinson disease patients. The laser line method is applied to detect the dorsum manus vibration in rest and postural situations. The proposed measurement system mainly consists of a laser diode and a low cost complementary metal-oxide semiconductor (cmos) imagesensor. Laser line and centroid methods are combined with the Fast Fourier Transform (FFT) in this study. The shape and frequency and relative frequency of the dorsum manus vibration waveforms can be detected rapidly using our Parkinson's disease measurement system. A laser line near the wrist joint is used as the testing line. The experimental results show an obvious increase in the amplitude and frequency of dorsum manus variation in the measured region in patients suffering from Parkinson's disease, indicating the obvious effects of the disease. Both in postural and rest state measurements, as the patient disease age increases the vibration frequency increases. The measurement system is well suited for evaluating and pre-diagnosing early stage Parkinson's disease.
cmos image sensors with logarithmic response are attractive devices for applications where a high dynamic range is required. Their strong point is the high dynamic range, Their weak point is the sensitivity to pixel p...
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cmos image sensors with logarithmic response are attractive devices for applications where a high dynamic range is required. Their strong point is the high dynamic range, Their weak point is the sensitivity to pixel parameter variations introduced during fabrication. This gives rise to a considerable fixed pattern noise (FPN) that deteriorates the image quality unless pixel calibration is used. In the present work a technique to remove the FPN by employing on-chip calibration is introduced, where the effect of threshold voltage variations in pixels is cancelled, An imagesensor based on an active pixel structure with five transistors has been designed, fabricated, and tested. The sensor consists of 525 x 525 pixels measuring 7.5 mu m x 10 mu m, and is fabricated in a 0.5-mu m cmos process, The measured dynamic range is 120 dB while the FPN is 2.5% of the output signal range.
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