Effect of Thin Film Thicknesses and Materials on the Response of RTDs and Microthermocouples

Imran, Muhammad; Bhattacharyya, Abhijit

doi:10.1109/jsen.2006.884167

Cited by 27 publications

(17 citation statements)

References 18 publications

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“…One practical solution is to apply multiple discrete temperature sensors to the skin such as thermocouples (11), thermistors (12), or resistive temperature detectors (4,6,13) with individual wirings for data readout. Indeed, there are many excellent temperature sensors that exhibit fast response, mechanical flexibility, physiological stability, and/or high sensitivity (4,6,13).…”

mentioning

confidence: 99%

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

Yokota

Inoue

Terakawa

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

320

298

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We report a fabrication method for flexible and printable thermal sensors based on composites of semicrystalline acrylate polymers and graphite with a high sensitivity of 20 mK and a high-speed response time of less than 100 ms. These devices exhibit large resistance changes near body temperature under physiological conditions with high repeatability (1,800 times). Device performance is largely unaffected by bending to radii below 700 μm, which allows for conformal application to the surface of living tissue. The sensing temperature can be tuned between 25°C and 50°C, which covers all relevant physiological temperatures. Furthermore, we demonstrate flexible active-matrix thermal sensors which can resolve spatial temperature gradients over a large area. With this flexible ultrasensitive temperature sensor we succeeded in the in vivo measurement of cyclic temperatures changes of 0.1°C in a rat lung during breathing, without interference from constant tissue motion. This result conclusively shows that the lung of a warm-blooded animal maintains surprising temperature stability despite the large difference between core temperature and inhaled air temperature. T emperature control plays a very important role in homeostasis, and body temperature varies both spatially and temporally in an effort to transfer heat between the living body and the environment via skin and respiratory organs. Accurate measurement of localized temperature changes in soft tissue regardless of large-scale motion is important in understanding thermal phenomena of homeostasis and realizing future sophisticated health diagnostics (1-3). Therefore, flexible temperature sensors which softly interface with tissue have been investigated frequently for applications in the medical field. However, these applications require the combination of sensitivity, fast response time, stability in physiological environments, and multipoint measurement. Before this work, to our knowledge, no experiment has simultaneously demonstrated orders-of-magnitude changes in electrical properties (sensitivity) repeatedly at varying physiological temperatures and conditions (stability) in a robust, easy-to-fabricate, flexible temperature sensor (processability).When sensors and electronics are directly attached to the surface of an animal body, the use of soft and flexible electronic devices is expected to reduce mechanical stress induced on the body. From this viewpoint, the field of flexible electronics has attracted much attention recently. The ability to gather information such as pressure and temperature from curvilinear and dynamic surfaces without impairing the movement or usability of the users is unmatched by conventional silicon electronics. There have been reports of the potential application of flexible electrodes on ultrathin substrates (4), flexible sensors that measure biological signals, electrocardiograms, temperature, pressure (5, 6), organic amplifier systems (7), high-sensitivity pressure sensors (8), and ultrathin and imperceptible devices (9, 10).To meas...

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mentioning

confidence: 99%

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

Yokota

Inoue

Terakawa

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

320

298

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“…Remote temperature sensors would offer the possibility of monitoring temperature of human body, perishable food and medicine by simply attaching a flexible tag. Several types of temperature sensors have been fabricated on flexible substrates, such as thermocouples,3 resistive temperature detectors (RTDs),4 and organic diodes 5. Thermocouples are based on the Seebeck effect and typically generate a voltage change between 40 to 70 μV/°C 3, 6.…”

Section: Ptc Effects Of the Several Investigated Polymersmentioning

confidence: 99%

Flexible Wireless Temperature Sensors Based on Ni Microparticle‐Filled Binary Polymer Composites

Jeon¹,

Lee²,

Bao³

2012

Advanced Materials

300

255

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Flexible and disposable sensors have great potential toward applications such as medical diagnostics, food safety and environmental monitoring. [ 1 , 2 ] Radio frequency identifi cation (RFID) tags were originally developed for identifi cation and tracking purposes. When RFID tags are combined with fl exible organic sensors, they could function as wireless sensors while possessing the merits of organic electronics, such as mechanical fl exibility, light weight and low cost. Remote temperature sensors would offer the possibility of monitoring temperature of human body, perishable food and medicine by simply attaching a fl exible tag. Several types of temperature sensors have been fabricated on fl exible substrates, such as thermocouples, [ 3 ] resistive temperature detectors (RTDs), [ 4 ] and organic diodes. [ 5 ] Thermocouples are based on the Seebeck effect and typically generate a voltage change between 40 to 70 μ V/ ° C. [ 3 , 6 ] As the resistance change of a standard 100 Ω RTD is only 0.4 Ω / ° C, [ 3 , 6 ] the readout of these temperature sensors requires hihgly accurate and complex electronic circuits, i.e. high gain amplifi ers and high precision analog to digital converters (ADCs), [ 7 ] making it diffi cult for integration and hence increases the overall cost in their fabrication process.In this work, we developed Ni microparticle-fi lled binary polymer composites as temperature sensors with greater improved reproducibility compared to single polymer composites. These materials showed a much higher sensitivity than other types of fl exible temperature sensors. In addition, the higher improved sensitivity enabled us to fabricate a wireless temperature sensor by integrating it with a passive RFID antenna. Our temperature sensor consists of a Ni microparticle-fi lled binary polymer composite with polyethylene (PE) and polyethylene oxide (PEO) as the matrix designed to be highly sensitive for monitoring human body temperature. Conductive particle-fi lled polymer composites have already been widely used commercially as antistatic and electromagnetic interference shielding materials. [ 8 ] In addition, it has also been shown that some polymer composites showed several orders of resistivity change with temperature. This phenomenon has been explored for self-limiting heating elements, over-current protectors and resettable fuses. [ 9 ] However, conductive particle-fi lled polymer composites have yet been used as temperature sensor. This is primarily due to the diffi culty in achieving a reproducible temperature sensing response. [10][11][12] Additionally, the sensitive ranges previously reported were > 70 ° C, [13][14][15] which is much higher than the temperature range needed for medical diagnostics, food safety and environmental monitoring.In our system, we chose a matrix polymer blend with both semi-crystalline PEO and PE. The resistivity versus temperature characteristic of a metal microparticle-fi lled polymer is determined largely by the thermal behavior of the polymer. As shown in Table 1 , amorphous ...

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“…The heat generated in the resistive heaters (Joule heating) as well as the response of the temperature sensors at different temperatures were obtained by solving the equations in the electrical domain. The temperature coefficient of resistance (TCR) of the temperature sensors (prototype TAMU/ULL-03), which represents the sensitivity of the sensor resistance to a change in temperature (Imran and Bhattacharyya, 2006), was 0.4%/ C (calculated using the models constructed in COMSOL Multiphysics).…”

Section: Design Aspects Of the Devices Fabricated At Tamu/ullmentioning

confidence: 99%

Chip-scale calorimeters: Potential uses in chemical engineering

Carreto-Vazquez

Liu

Bukur

et al. 2011

Journal of Loss Prevention in the Process Industries

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Effect of Thin Film Thicknesses and Materials on the Response of RTDs and Microthermocouples

Cited by 27 publications

References 18 publications

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

Ultraflexible, large-area, physiological temperature sensors for multipoint measurements

Flexible Wireless Temperature Sensors Based on Ni Microparticle‐Filled Binary Polymer Composites

Chip-scale calorimeters: Potential uses in chemical engineering

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