scholarly journals Optimised Performance of Non-Dispersive Infrared Gas Sensors Using Multilayer Thin Film Bandpass Filters

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 472 ◽  
Author(s):  
Pinggui Wang ◽  
Xiuhua Fu ◽  
Des Gibson ◽  
Lewis Fleming ◽  
Sam Ahmadzadeh ◽  
...  
Keyword(s):  
Thin Film ◽  
Work Performance ◽  
Microwave Plasma ◽  
Light Emitting Diode ◽  
Spectral Characteristics ◽  
Optical Filter ◽  
Deposition Process ◽  
Bandpass Filters ◽  
Temperature Sensitive ◽  
Sensor Performance

In this work, performance improvements are described for a low-power consumption non-dispersive infrared (NDIR) methane (CH4) gas sensor using customised optical thin film bandpass filters (BPFs) centered at 3300 nm. BPFs shape the spectral characteristics of the combined mid-infrared III–V based light emitting diode (LED)/photodiode (PD) light source/detector optopair, enhancing the NDIR CH4 sensor performance. The BPFs, deposited using a novel microwave plasma-assisted pulsed DC sputter deposition process, provide room temperature deposition directly onto the temperature-sensitive PD heterostructure. BPFs comprise germanium (Ge) and niobium pentoxide (Nb2O5) alternating high and low refractive index layers, respectively. Two different optical filter designs are progressed with BPF bandwidths (BWs) of 160 and 300 nm. A comparison of the modelled and measured NDIR sensor performance is described, highlighting the maximised signal-to-noise ratio (SNR) and the minimised cross-talk performance benefits. The BPF spectral stability for various environmental temperature and humidity conditions is demonstrated.

scholarly journals Optimised Performance of Non-Dispersive Infrared Gas Sensors Using Multilayer Thin Film Bandpass Filters

2018 ◽  
Author(s):  
Pinggui Wang ◽  
Xiuhua Fu ◽  
Des Gibson ◽  
Lewis Fleming ◽  
Cheng Li ◽  
...  
Keyword(s):  
Thin Film ◽  
Work Performance ◽  
Microwave Plasma ◽  
Signal To Noise Ratio ◽  
Light Emitting Diode ◽  
Optical Filter ◽  
Deposition Process ◽  
Bandpass Filters ◽  
Temperature Sensitive ◽  
Sensor Performance

In this work performance improvements are described of a low power consumption non-dispersive infrared (NDIR) methane (CH4) gas sensor using customised optical thin film bandpass filters (BPF). BPF’s shape the spectral characteristic of the combined mid infrared III-V based light emitting diode (LED)/ photodiode (PD) light source/detector optopair, enhancing NDIR CH4 sensor performance. The BPF, deposited using a novel microwave plasma assisted pulsed DC sputter deposition process, is deposited at room temperature directly onto the temperature sensitive PD heterostructure. BPF’s comprise germanium (Ge) and niobium pentoxide (Nb2O5) alternating high and low refractive index layers respectively. Two different optical filter designs are progressed; with BPF bandwidths (BWs) of 160 nm and 300 nm. Comparison of modelled and measured NDIR sensor performance is described, highlighting maximized signal to noise ratio (SNR) and minimized cross talk performance benefits. BPF spectral stability for various environmental temperature and humidity conditions is demonstrated.  

Preparation and Processing of PZT Thin Film by Liquid Mist Microwave Plasma Enhanced Chemical Vapour Deposition

2011 ◽  
Vol 295-297 ◽  
pp. 1747-1750 ◽  
Author(s):  
Jun Jie Hao ◽  
Yang Yang Li ◽  
Hui Ming Ji
Keyword(s):  
Thin Film ◽  
Chemical Vapour Deposition ◽  
Vapour Deposition ◽  
Microwave Plasma ◽  
Special Functions ◽  
Chemical Vapour ◽  
Chelating Agent ◽  
Deposition Process ◽  
Water Solvent ◽  
Pzt Thin Film

PZT thin film was prepared on platinized Si substrates by liquid-source mist microwave plasma enhanced chemical vapour deposition. Using citric amine and ethylene glycol as chelating agent, a homogeneous, stable water solvent sol was prepared successfully, which was suitable to develop PZT thin film by LSMPECVD. From the analysis of FTIR spectra, the special functions of chelating agents were identified. It shows that this deposition process is nonuniform nucleation, the PZT thin film grew with island model. Prior to fill the blank sites on the substrate, the latter deposited PZT congregated together to reduce surface energy. The morphology and structure were characterized by SEM and XRD analysis.

scholarly journals LED Light Improved by an Optical Filter to Visible Solar-Like Light with High Color Rendering

Coatings ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 763
Author(s):  
Li-Siang Shen ◽  
Hsing-Yu Wu ◽  
Li-Jen Hsiao ◽  
Chih-Hsuan Shih ◽  
Jin-Cherng Hsu
Keyword(s):  
Light Emitting Diode ◽  
Multilayer Coating ◽  
Optical Filter ◽  
Deposition Process ◽  
Color Temperature ◽  
Light Sources ◽  
White Led ◽  
Easy Method ◽  
The Cost ◽  
Color Rendering

In this study, a new, cost-effective, rapid, and easy method to produce a sunlight-like D65 light source from a typical white light-emitting diode (LED) is discussed. The novelty of this method is that the emission spectrum of a typical white LED is measured first, then the reverse spectrum is used to design and fabricate a double-sided multilayer coating filter to set in front of the typical white LED. This can be verified experimentally to improve the color-rendering index of the white LED to 95.8 at the D65 color temperature. The optical thicknesses of the multilayer film are designed at a quarter wavelength. The layer-thickness errors during the deposition process are reduced due to easy monitoring with the turning-point method. By lowering both the cost and level of technology required to produce D65 light sources, in addition to the most direct consequences of increased D65 availability and affordability, the cost and level of technology required for research that heavily utilizes D65 light sources can also be lowered in turn, especially in the fields of clinical science, medicine, and related industries.

Reaction couples of ceramic thin films prepared by CVD

1988 ◽  
Vol 46 ◽  
pp. 798-799
Author(s):  
D.W. Susnitzky ◽  
S.R. Summerfelt ◽  
C.B. Carter
Keyword(s):  
Thin Film ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Solid State Reactions ◽  
Spatial Distributions ◽  
Diffusion Couples ◽  
Kinetics Studies ◽  
Ceramic Thin Films ◽  
Initial Stage

Solid-state reactions have traditionally been studied in the form of diffusion couples. This ‘bulk’ approach has been modified, for the specific case of the reaction between NiO and Al2O3, by growing NiAl2O4 (spinel) from electron-transparent Al2O3 TEM foils which had been exposed to NiO vapor at 1415°C. This latter ‘thin-film’ approach has been used to characterize the initial stage of spinel formation and to produce clean phase boundaries since further TEM preparation is not required after the reaction is completed. The present study demonstrates that chemical-vapor deposition (CVD) can be used to deposit NiO particles, with controlled size and spatial distributions, onto Al2O3 TEM specimens. Chemical reactions do not occur during the deposition process, since CVD is a relatively low-temperature technique, and thus the NiO-Al2O3 interface can be characterized. Moreover, a series of annealing treatments can be performed on the same sample which allows both Ni0-NiAl2O4 and NiAl2O4-Al2O3 interfaces to be characterized and which therefore makes this technique amenable to kinetics studies of thin-film reactions.

scholarly journals Influences of Spectral Power Distribution on Circadian Energy, Visual Comfort and Work Performance

2021 ◽  
Vol 13 (9) ◽  
pp. 4852
Author(s):  
Jack Ngarambe ◽  
Inhan Kim ◽  
Geun Young Yun
Keyword(s):  
Light Source ◽  
Power Distribution ◽  
Work Performance ◽  
Spectral Power ◽  
Light Emitting Diode ◽  
Essential Element ◽  
Visual Comfort ◽  
Light Emitting ◽  
Organic Light Emitting Diode ◽  
Spectral Power Distribution

Spectral power distribution (SPD) is an essential element that has considerable implications on circadian energy and the perception of lit environments. The present study assessed the potential influences of SPD on energy consumption (i.e., considering circadian energy), visual comfort, work performance and mood. Two lighting conditions based on light-emitting diode (LED) and organic light-emitting diode (OLED) were used as proxies for SPDs of different spectral content: dominant peak wavelength of 455 nm (LED) and 618 nm (OLED). Using measured photometric values, the circadian light (CL), melatonin suppression (MS), and circadian efficacy (CE) of the two lighting sources were estimated via a circadian-phototransduction model and compared. Additionally, twenty-six participants were asked to evaluate the said lit environments subjectively in terms of visual comfort and self-reported work performance. Regarding circadian lighting and the associated energy implications, the LED light source induced higher biological actions with relatively less energy than the OLED light source. For visual comfort, OLED lighting-based conditions were preferred to LED lighting-based conditions, while the opposite was true when considering work performance and mood. The current study adds to the on-going debate regarding human-centric lighting, particularly considering the role of SPD in energy-efficient and circadian lighting practices.

Preparation of boron carbide thin film by pulsed KrF excimer laser deposition process

2002 ◽  
Vol 407 (1-2) ◽  
pp. 126-131 ◽  
Author(s):  
Shin-ichi Aoqui ◽  
Hisatomo Miyata ◽  
Tamiko Ohshima ◽  
Tomoaki Ikegami ◽  
Kenji Ebihara
Keyword(s):  
Thin Film ◽  
Boron Carbide ◽  
Excimer Laser ◽  
Deposition Process ◽  
Laser Deposition ◽  
Krf Excimer Laser

Organic Light Emitting Material Direct Writing by Nanomaterial Enabled Laser Transfer

2009 ◽  
Vol 1179 ◽  
Author(s):  
Seung Hwan Ko ◽  
Heng Pan ◽  
Nipun Misra ◽  
Costas Grigoropoulos
Keyword(s):  
Mass Production ◽  
Laser Energy ◽  
Light Emitting Diode ◽  
Nanoparticle Size ◽  
Temperature Sensitive ◽  
Conductive Heat ◽  
Direct Writing ◽  
Light Emitting ◽  
Laser Transfer ◽  
Organic Light

AbstractOrganic light emitting material direct writing is demonstrated based on nanomaterial enabled laser transfer. Through utilization of proper nanoparticle size and type, and the laser wavelength choice, a single laser pulse could transfer well defined and arbitrarily shaped tris-(8-hydroxyquinoline)Al patterns ranging from several microns to millimeter size. The unique properties of nanomaterials allow laser induced forward transfer at low laser energy (0.05 J/cm2) while maintaining good fluorescence. The technique may be well suited for the mass production of temperature sensitive organic light emitting devices.The combined effects of melting temperature depression, lower conductive heat transfer loss, strong absorption of the incident laser beam, and relatively weak bonding between nanoparticles during laser irradiation result in the transfer of patterns with very sharp edges at relatively lower laser energy than commonly used, thus inducing minimal damage to the target organic light emitting diode material with no evidence of cracks. This technique can be applied to a broad range of laser wavelengths with proper selection of nanoparticle size and size distribution, as well as the material type. Additionally, nanomaterial enabled laser transfer may be particularly advantageous for the mass production of temperature sensitive devices.

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