scholarly journals Optofluidic Formaldehyde Sensing: Towards On-Chip Integration

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 673 ◽  
Author(s):  
Daniel Mariuta ◽  
Arumugam Govindaraji ◽  
Stéphane Colin ◽  
Christine Barrot ◽  
Stéphane Le Calvé ◽  
...  
Keyword(s):  
Absorption Coefficient ◽  
Detection System ◽  
Fluorescence Emission ◽  
Complementary Metal Oxide Semiconductor ◽  
Image Sensor ◽  
Air Pollutant ◽  
Oxide Semiconductor ◽  
Excitation Wavelength ◽  
Formaldehyde Concentration ◽  
On Chip

Formaldehyde (HCHO), a chemical compound used in the fabrication process of a broad range of household products, is present indoors as an airborne pollutant due to its high volatility caused by its low boiling point ( T = − 19 °C). Miniaturization of analytical systems towards palm-held devices has the potential to provide more efficient and more sensitive tools for real-time monitoring of this hazardous air pollutant. This work presents the initial steps and results of the prototyping process towards on-chip integration of HCHO sensing, based on the Hantzsch reaction coupled to the fluorescence optical sensing methodology. This challenge was divided into two individually addressed problems: (1) efficient airborne HCHO trapping into a microfluidic context and (2) 3,5–diacetyl-1,4-dihydrolutidine (DDL) molecular sensing in low interrogation volumes. Part (2) was addressed in this paper by proposing, fabricating, and testing a fluorescence detection system based on an ultra-low light Complementary metal-oxide-semiconductor (CMOS) image sensor. Two three-layer fluidic cell configurations (quartz–SU-8–quartz and silicon–SU-8–quartz) were tested, with both possessing a 3.5 µL interrogation volume. Finally, the CMOS-based fluorescence system proved the capability to detect an initial 10 µg/L formaldehyde concentration fully derivatized into DDL for both the quartz and silicon fluidic cells, but with a higher signal-to-noise ratio (SNR) for the silicon fluidic cell ( S N R s i l i c o n = 6.1 ) when compared to the quartz fluidic cell ( S N R q u a r t z = 4.9 ). The signal intensity enhancement in the silicon fluidic cell was mainly due to the silicon absorption coefficient at the excitation wavelength,   a ( λ a b s = 420   nm ) = 5 × 10 4   cm − 1 , which is approximately five times higher than the absorption coefficient at the fluorescence emission wavelength, a ( λ e m = 515   nm ) = 9.25 × 10 3   cm − 1 .

scholarly journals Compensation for Process and Temperature Dependency in a CMOS Image Sensor

Sensors ◽  
2019 ◽  
Vol 19 (4) ◽  
pp. 870 ◽  
Author(s):  
Shuang Xie ◽  
Albert Theuwissen
Keyword(s):  
Complementary Metal Oxide Semiconductor ◽  
Process Variations ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Temperature Sensors ◽  
Oxide Semiconductor ◽  
Temperature Dependency ◽  
Image Pixels ◽  
On Chip ◽  
Dark Signal

This paper analyzes and compensates for process and temperature dependency among a (Complementary Metal Oxide Semiconductor) CMOS image sensor (CIS) array. Both the analysis and compensation are supported with experimental results on the CIS’s dark current, dark signal non-uniformity (DSNU), and conversion gain (CG). To model and to compensate for process variations, process sensors based on pixel source follower (SF)’s transconductance gm,SF have been proposed to model and to be compared against the measurement results of SF gain ASF. In addition, ASF’s thermal dependency has been analyzed in detail. To provide thermal information required for temperature compensation, six scattered bipolar junction transistor (BJT)-based temperature sensors replace six image pixels inside the array. They are measured to have an untrimmed inaccuracy within ±0.5 ⁰C. Dark signal and CG’s thermal dependencies are compensated using the on-chip temperature sensors by at least 79% and 87%, respectively.

scholarly journals Ultrasensitive interferometric on-chip microscopy of transparent objects

2016 ◽  
Vol 2 (6) ◽  
pp. e1600077 ◽  
Author(s):  
Roland A. Terborg ◽  
Josselin Pello ◽  
Ilaria Mannelli ◽  
Juan P. Torres ◽  
Valerio Pruneri
Keyword(s):  
Complementary Metal Oxide Semiconductor ◽  
Image Sensor ◽  
Phase Shifts ◽  
Oxide Semiconductor ◽  
Large Field ◽  
Interference Effects ◽  
Physical Processes ◽  
Detection Volume ◽  
Transparent Objects ◽  
On Chip

Light microscopes can detect objects through several physical processes, such as scattering, absorption, and reflection. In transparent objects, these mechanisms are often too weak, and interference effects are more suitable to observe the tiny refractive index variations that produce phase shifts. We propose an on-chip microscope design that exploits birefringence in an unconventional geometry. It makes use of two sheared and quasi-overlapped illuminating beams experiencing relative phase shifts when going through the object, and a complementary metal-oxide-semiconductor image sensor array to record the resulting interference pattern. Unlike conventional microscopes, the beams are unfocused, leading to a very large field of view (20 mm2) and detection volume (more than 0.5 cm3), at the expense of lateral resolution. The high axial sensitivity (<1 nm) achieved using a novel phase-shifting interferometric operation makes the proposed device ideal for examining transparent substrates and reading microarrays of biomarkers. This is demonstrated by detecting nanometer-thick surface modulations on glass and single and double protein layers.

scholarly journals Low-Cost 2D Index and Straightness Measurement System Based on a CMOS Image Sensor

Sensors ◽  
2019 ◽  
Vol 19 (24) ◽  
pp. 5461 ◽  
Author(s):  
Alain Küng ◽  
Benjamin A. Bircher ◽  
Felix Meli
Keyword(s):  
Measurement System ◽  
Degrees Of Freedom ◽  
Low Cost ◽  
Complementary Metal Oxide Semiconductor ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Oxide Semiconductor ◽  
Measurement Systems ◽  
Starting Point ◽  
Sensor Properties

Accurate traceable measurement systems often use laser interferometers for position measurements in one or more dimensions. Since interferometers provide only incremental information, they are often combined with index sensors to provide a stable reference starting point. Straightness measurements are important for machine axis correction and for systems having several degrees of freedom. In this paper, we investigate the accuracy of an optical two-dimensional (2D) index sensor, which can also be used in a straightness measurement system, based on a fiber-coupled, collimated laser beam pointing onto an image sensor. Additionally, the sensor can directly determine a 2D position over a range of a few millimeters. The device is based on a simple and low-cost complementary metal–oxide–semiconductor (CMOS) image sensor chip and provides sub-micrometer accuracy. The system is an interesting alternative to standard techniques and can even be implemented on machines for real-time corrections. This paper presents the developed sensor properties for various applications and introduces a novel error separation method for straightness measurements.

scholarly journals Angular Light, Polarization and Stokes Parameters Information in a Hybrid Image Sensor with Division of Focal Plane

Sensors ◽  
2020 ◽  
Vol 20 (12) ◽  
pp. 3391
Author(s):  
Francelino Freitas Carvalho ◽  
Carlos Augusto de Moraes Cruz ◽  
Greicy Costa Marques ◽  
Kayque Martins Cruz Damasceno
Keyword(s):  
Integrated Circuit ◽  
Incident Angle ◽  
Complementary Metal Oxide Semiconductor ◽  
Image Sensor ◽  
Light Polarization ◽  
Oxide Semiconductor ◽  
Stokes Parameters ◽  
New Paradigm ◽  
Depth Sensing ◽  
3D Image Reconstruction

Targeting 3D image reconstruction and depth sensing, a desirable feature for complementary metal oxide semiconductor (CMOS) image sensors is the ability to detect local light incident angle and the light polarization. In the last years, advances in the CMOS technologies have enabled dedicated circuits to determine these parameters in an image sensor. However, due to the great number of pixels required in a cluster to enable such functionality, implementing such features in regular CMOS imagers is still not viable. The current state-of-the-art solutions require eight pixels in a cluster to detect local light intensity, incident angle and polarization. The technique to detect local incident angle is widely exploited in the literature, and the authors have shown in previous works that it is possible to perform the job with a cluster of only four pixels. In this work, the authors explore three novelties: a mean to determine three of four Stokes parameters, the new paradigm in polarization cluster-pixel design, and the extended ability to detect both the local light angle and intensity. The features of the proposed pixel cluster are demonstrated through simulation program with integrated circuit emphasis (SPICE) of the regular Quadrature Pixel Cluster and Polarization Pixel Cluster models, the results of which are compliant with experimental results presented in the literature.

A Very Low Dark Current Temperature-Resistant, Wide Dynamic Range, Complementary Metal Oxide Semiconductor Image Sensor

2008 ◽  
Vol 47 (7) ◽  
pp. 5390-5395 ◽  
Author(s):  
Koichi Mizobuchi ◽  
Satoru Adachi ◽  
Jose Tejada ◽  
Hiromichi Oshikubo ◽  
Nana Akahane ◽  
...  
Keyword(s):  
Metal Oxide ◽  
Dark Current ◽  
Dynamic Range ◽  
Complementary Metal Oxide Semiconductor ◽  
Image Sensor ◽  
Metal Oxide Semiconductor ◽  
Oxide Semiconductor ◽  
Wide Dynamic Range
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