A Novel MEMS Respiratory Flow Sensor

Abstract

Our experience in the design of an ultra-high speed image sensor targeting the theoretical maximum frame rate is summarized. The imager is the backside illuminated in situ storage image sensor (BSI ISIS). It is confirmed that the critical factor limiting the highest frame rate is the signal electron transit time from the generation layer at the back side of each pixel to the input gate to the in situ storage area on the front side. The theoretical maximum frame rate is estimated at 100 Mega-frames per second (Mfps) by transient simulation study. The sensor has a spatial resolution of 140,800 pixels with 126 linear storage elements installed in each pixel. The very high sensitivity is ensured by application of backside illumination technology and cooling. The ultra-high frame rate is achieved by the in situ storage image sensor (ISIS) structure on the front side. In this paper, we summarize technologies developed to achieve the theoretical maximum frame rate, including: (1) a special p-well design by triple injections to generate a smooth electric field backside towards the collection gate on the front side, resulting in much shorter electron transit time; (2) design technique to reduce RC delay by employing an extra metal layer exclusively to electrodes responsible for ultra-high speed image capturing; (3) a CCD specific complementary on-chip inductance minimization technique with a couple of stacked differential bus lines.

Biomedical Electronic Systems to Improve the Healthcare Quality and Efficiency

“…With this calibration, we hope that this physical activity measurement would allow a good quantitative estimator of the energetic expenses to what concern walking and running, and we hope that, using also other biological parameters to evaluate basic metabolism, it could be possible to estimate the daily energetic expenses. This would be very interesting since available method that measure the CO 2 , with mouth and nose tubing (Lay-Ekuakille et al, 2010) (Wei et al, 2010)., and the heat production (in a calorimetric box) are not suited for 24 hour measurements.…”

“…In the first method, the air flow is sensed while in the second one the breast dilatation is sensed. Air flow monitoring is accurate but is very uncomfortable, since it requires tubing or placing sensors both in mouth and in nose (Lay-Ekuakille et al, 2010) (Wei et al, 2010). This would rule out 24 hours logging.…”

A low-power thermal-based sensor system for low air flow detection

“…This rapidly increasing trend in the use of air flow sensing systems is being dictated by the sensor type, power consumption, linearity, and form factor of the system. The several types of sensors being utilized for low air flow measurements can be broadly categorized as thermistors thermopiles [1], pyroelectric elements [2], pn junctions [3], intensity modulated fiber optic [4], ultrasound based [5], micro-electro-mechanical systems based [6], capacitive based [7]–[8], electromagnet based [9]–[10], resonating microbridges [11] and prandtl tubes [12] among others. One category of air flow sensor uses an indirect measurement such as the air temperature [13], volume or pressure [14] to determine the air flow.…”

Capacitive sensor for respiration monitoring

“…There are several methods that are used for respiratory monitoring purposes in different settings and scenarios. Spirometers and carbon dioxide sensors are usually used in a clinical setting [7], [8], and they require contact with patient's airflow, thus affecting the patient's freedom of doing normal everyday activities. Other less invasive and obstructive methods encompass the use of piezoelectric sensors, resistive sensors, respiratory inductive plethysmographs, Doppler effect sensors, acoustic sensors, ultrasonic sensors, electromagnetic sensing, impulse radio ultrawideband (UWB) contactless respiratory monitoring, bioimpedance measurements, camera based approaches, fiber Bragg gratings sensors [9]- [18] etc.…”