Design and Fabrication of a Low-Cost Thermopile Infrared Detector

Liang, Ting; Guan, Yihao; Cheng, Liang; Wu, Xuezhan; Bai, Yuehang; Xiong, Jijun; Qi, Lei

doi:10.3390/mi12091134

Cited by 7 publications

(3 citation statements)

References 11 publications

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“…Every object emits more infrared (IR) light when heated. IR lenses and thermopile sensors [260] are typically used to sense heat (via IR light). Using this method, the skin temperatures of humans and animals can be measured [261].…”

Section: ) Infrared (Ir) Near Ir (Nir) Spectroscopy (Nirs) and Functi...mentioning

confidence: 99%

Review of Stress Detection Methods Using Wearable Sensors

Taskasaplidis,

Fotiadis,

Bamidis

2024

IEEE Access

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Stress is a significant factor that affects well-being and health. Factors that trigger stress include work, social interactions, and economic and environmental factors. Stress may cause lower labor productivity, physical and mental health problems, and malfunctions in all social aspects of life. Psychosomatic health can be improved if proper stress detection mechanisms are present in daily life and stress reduction methods can occur. Wearable sensors are currently used in many commercial and scientific applications in a non-destructive or annoying manner. These devices are used in daily routines. In this paper, a comprehensive review of the latest literature and developments in stress detection methods is presented through extensive and holistic research on stress response, both at the level of the autonomic nervous system (ANS) and hypothalamic-pituitary-adrenal axis (HPA). This study focused on the exploitation of various methods, technologies, and data analysis systems to understand stress in a multifaceted and comprehensive manner. Various stress-related factors are presented along with biological signal measurements, and physical secretions or biomarkers are primarily used for stress detection. Furthermore, the manner in which body movement and posture measurements may be related to stress was investigated, together with speech and hand tremors. Various stress-detection technologies have been analyzed, and existing data analysis methods that can be applied to stress-detection systems have been highlighted. This review serves as a reference and guideline for exploring this area of interest, identifying research opportunities, and offering ideas, options, and suggestions for optimized solutions regarding future applications and research.

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Section: ) Infrared (Ir) Near Ir (Nir) Spectroscopy (Nirs) and Functi...mentioning

confidence: 99%

Review of Stress Detection Methods Using Wearable Sensors

Taskasaplidis,

Fotiadis,

Bamidis

2024

IEEE Access

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“…The main design elements of the designed thermopiles, although different in structure, are essentially the same. The detailed information for theory analysis and design can be found in our previous reports [17,18].…”

Section: Structure Designmentioning

confidence: 99%

Micromachined Infrared Thermopile Detector Based on a Suspended Film Structure

et al. 2023

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The micro-electromechanical system (MEMS) infrared thermopile is the core working device of modern information detection systems such as spectrometers, gas sensors, and remote temperature sensors. We presented two different structures of MEMS infrared thermopiles based on suspended film structures. They both deposited silicon nitride over the entire surface as a passivated absorber layer in place of a separate absorber zone, and the thermocouple strip was oriented in the same direction as the temperature gradient. The same MEMS preparation process was used and finally two different structures of the thermopile were characterized separately for testing to verify the impact of our design on the detector. The test results show that the circular and double-ended symmetrical thermopile detectors have responsivities of 27.932 V/W and 23.205 V/W, specific detectivities of 12.1×107 cm·Hz1/2·W−1 and 10.1×107 cm·Hz1/2·W−1, and response time of 26.2 ms and 27.06 ms, respectively. In addition, rectangular double-ended symmetric thermopile has a larger field of view than a circular thermopile detector, but is not as mechanically stable as a circular thermopile.

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“…The Seebeck effect is the electromotive force (emf) that develops across two points of an electrically conducting material when there is a temperature difference between them. Figure 2.3 shows a bulk micromachined thermopile detector [112]. The microbolometer is based on resistance changes due to temperature changes that accompany the absorption of infrared radiation.…”

Section: Thermal Detector Versus Photon Detectormentioning

confidence: 99%

Metasurface integrated uncooled silicon germanium oxide microbolometers for long wavelength infrared detection

Alkorjia¹

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[EMBARGOED UNTIL 6/1/2023] This report presents the design, fabrication, characterization, and noise optimization of metasurface enabled uncooled infrared (IR) microbolometers based on silicon germanium oxide (Si0.344Ge0.602O0.054), (Si0.425Ge0.512 O0.063). The metasurface enabled fabrication of the microbolometer with the supporting arms placed underneath the pixel without disrupting the Fabry-Perot resonant cavity typically used in conventional microbolometers. This allowed fabrication of the microbolometer with longer supporting arms without sacrificing the fill factor and thus increased the voltage responsivity. The longer support arms reduced the thermal conductance between the microbolometer pixel and the underlying substrate. The metasurface also allowed the IR absorption to be engineered to achieve broadband or narrowband response. The measured voltage responsivity, detectivity, and thermal response time were 1.52x104 V/W, 2.5x107 cm Hz1/2/W and 2.01 m seconds to filtered blackbody IR between 2-14 [mu]m. The voltage noise power spectral density (PSD) of the fabricated devices were reduced by annealing the devices in vacuum. In addition, the measured TCR, thermal conductance Gth, and absorptivity were 2.5 percent/K, 4.44x10-8 W/K, and 39 percent, respectively. The voltage noise power spectral density (PSD) of the fabricated devices with a different composition (SiGeO) was optimized by annealing the devices in vacuum and in forming gases. The results demonstrated annealing in vacuum reduced the voltage noise level and shifted the corner frequency to a lower frequency than that of annealing in forming gases. The lowest measured voltage noise in vacuum and in forming gases at the corner frequencies were 1.723 x 10-15 V2/Hz at 17 Hz and 1.91x10-14 V2/Hz at 30 Hz, respectively. The voltage noise before annealing at the same bias current and corner frequency was 5.62 x 10-10 V2/Hz for annealing in vacuum, 4.33 x 10-10 V2/Hz for annealing in forming gases. This is 4.33 x 105 times and 1.27 x 104 times reduction in noise, respectively. The results also demonstrated that annealing in vacuum provided much lower voltage noise reduction than annealing in forming gases. In addition, annealing in vacuum and in forming gases has shifted the corner frequency from 85 Hz to 17 Hz and from 80 Hz to 30 Hz, respectively. The results demonstrated that the voltage noise at 17 Hz after annealing in vacuum is 45.2 times lower than that of annealing in forming gases. The corresponding Hooge's parameters ?, [beta], and Kf for the devices before and after annealing in vacuum were 1.25, 2.23, 3.26x10-10, and 1.02, 2.07, 2.375x10-14 and in forming gases were 1.26, 2.24, 2.435x10-11, and 1.06, 2.09, and 7.078x10-14, respectively. The value of ? is close to 1 after annealing which indicates that the 1/f-noise is dominant at low frequencies. The corresponding 1/f-noise coefficients Kf for the devices that were annealed in vacuum and forming gases were changed from 3.26x10-10 to 2.375x10-14 and from 2.435x10-11 to 7.078x10-14 after 4 hours of annealing at 300 degreesC. The value of Kf started to decrease after each annealing time interval. The decrease in Kf is attributed to the reduction of 1/f-noise. The [beta] value was close to 2 when the device was annealed for 4 hours. This indicates that the voltage noise increased linearly with increasing the bias current. The spectral responsivity and detectivity for the fabricated devices were measured in vacuum and demonstrated tunablility with narrowband between 7 to 16 [mu]m by changing the metasurface disk diameter and periodicity.

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Design and Fabrication of a Low-Cost Thermopile Infrared Detector

Cited by 7 publications

References 11 publications

Review of Stress Detection Methods Using Wearable Sensors

Review of Stress Detection Methods Using Wearable Sensors

Micromachined Infrared Thermopile Detector Based on a Suspended Film Structure

Metasurface integrated uncooled silicon germanium oxide microbolometers for long wavelength infrared detection

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