Mosaic pixel FPA technology comprises a novel microbolometer array design which, together with advanced packaging and integrated optics, can provide enhanced performance in short range sensing applications. Initially developed for passive infrared (PIR) security sensors, the technology can be applied to other non-military applications where a large pixel size is acceptable and a high detective performance is required. In this paper we discuss to two applications in depth: low cost thermography and non-imaging cheap sensors for pedestrian detection and other applications. Both have the advantage of very low NETD. We also discuss development of miniaturised IR sensors, as initially conceived for mosaic pixel technology.
{"title":"Application of mosaic pixel microbolometer technology to very high-performance, low-cost thermography and pedestrian detection","authors":"K. Liddiard","doi":"10.1117/12.2018593","DOIUrl":"https://doi.org/10.1117/12.2018593","url":null,"abstract":"Mosaic pixel FPA technology comprises a novel microbolometer array design which, together with advanced packaging and integrated optics, can provide enhanced performance in short range sensing applications. Initially developed for passive infrared (PIR) security sensors, the technology can be applied to other non-military applications where a large pixel size is acceptable and a high detective performance is required. In this paper we discuss to two applications in depth: low cost thermography and non-imaging cheap sensors for pedestrian detection and other applications. Both have the advantage of very low NETD. We also discuss development of miniaturised IR sensors, as initially conceived for mosaic pixel technology.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132022020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
E. Klem, Jay S. Lewis, C. Gregory, Garry B. Cunningham, D. Temple, A. D'Souza, E. Robinson, P. Wijewarnasuriya, N. Dhar
While InGaAs-based focal plane arrays (FPAs) provide excellent detectivity and low noise for SWIR imaging applications, wider scale adoption of systems capable of working in this spectral range is limited by high costs, limited spectral response, and costly integration with Si ROIC devices. RTI has demonstrated a novel photodiode technology based on IR-absorbing solution-processed PbS colloidal quantum dots (CQD) that can overcome these limitations of InGaAs FPAs. The most significant advantage of the CQD technology is ease of fabrication. The devices can be fabricated directly onto the ROIC substrate at low temperatures compatible with CMOS, and arrays can be fabricated at wafer scale. Further, device performance is not expected to degrade significantly with reduced pixel size. We present results for upward-looking detectors fabricated on Si substrates with sensitivity from the UV to ~1.7 µm. We further show devices fabricated with larger size CQDs that exhibit spectral sensitivity that extends from UV to 2 µm.
{"title":"Room temperature SWIR sensing from colloidal quantum dot photodiode arrays","authors":"E. Klem, Jay S. Lewis, C. Gregory, Garry B. Cunningham, D. Temple, A. D'Souza, E. Robinson, P. Wijewarnasuriya, N. Dhar","doi":"10.1117/12.2019521","DOIUrl":"https://doi.org/10.1117/12.2019521","url":null,"abstract":"While InGaAs-based focal plane arrays (FPAs) provide excellent detectivity and low noise for SWIR imaging applications, wider scale adoption of systems capable of working in this spectral range is limited by high costs, limited spectral response, and costly integration with Si ROIC devices. RTI has demonstrated a novel photodiode technology based on IR-absorbing solution-processed PbS colloidal quantum dots (CQD) that can overcome these limitations of InGaAs FPAs. The most significant advantage of the CQD technology is ease of fabrication. The devices can be fabricated directly onto the ROIC substrate at low temperatures compatible with CMOS, and arrays can be fabricated at wafer scale. Further, device performance is not expected to degrade significantly with reduced pixel size. We present results for upward-looking detectors fabricated on Si substrates with sensitivity from the UV to ~1.7 µm. We further show devices fabricated with larger size CQDs that exhibit spectral sensitivity that extends from UV to 2 µm.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"14 31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115581322","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huseyin Kayahan, Ömer Ceylan, M. Yazici, Y. Gurbuz
This paper presents a digital ROIC for staring type arrays with extending counting method to realize very low quantization noise while achieving a very high charge handling capacity. Current state of the art has shown that digital readouts with pulse frequency method can achieve charge handling capacities higher than 3Ge- with quantization noise higher than 1000e-. Even if the integration capacitance is reduced, it cannot be lower than 1-3 fF due to the parasitic capacitance of the comparator. For achieving a very low quantization noise of 200 electrons in a power efficient way, a new method based on measuring the time to measure the remaining charge on the integration capacitor is proposed. With this approach SNR of low flux pixels are significantly increased while large flux pixels can store electrons as high as 2.33Ge-. A prototype array of 32x32 pixels with 30μm pitch is implemented in 90nm CMOS process technology for verification. Simulation results are given for complete readout.
{"title":"A fully digital readout employing extended counting method to achieve very low quantization noise","authors":"Huseyin Kayahan, Ömer Ceylan, M. Yazici, Y. Gurbuz","doi":"10.1117/12.2018518","DOIUrl":"https://doi.org/10.1117/12.2018518","url":null,"abstract":"This paper presents a digital ROIC for staring type arrays with extending counting method to realize very low quantization noise while achieving a very high charge handling capacity. Current state of the art has shown that digital readouts with pulse frequency method can achieve charge handling capacities higher than 3Ge- with quantization noise higher than 1000e-. Even if the integration capacitance is reduced, it cannot be lower than 1-3 fF due to the parasitic capacitance of the comparator. For achieving a very low quantization noise of 200 electrons in a power efficient way, a new method based on measuring the time to measure the remaining charge on the integration capacitor is proposed. With this approach SNR of low flux pixels are significantly increased while large flux pixels can store electrons as high as 2.33Ge-. A prototype array of 32x32 pixels with 30μm pitch is implemented in 90nm CMOS process technology for verification. Simulation results are given for complete readout.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123305533","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we present a room-temperature micro-photonic bolometer that is based on the whispering gallery mode of dielectric resonator (WGM). The sensing element is a hollow micro-spherical optical polymeric resonator. The hollow resonator is filled with a fluid (gas or liquid) that has a large thermal expansion. When an incoming radiation impinges on the resonator is absorbed by the absorbing fluid leading to a thermal expansion of the micro-resonator. The thermal expansion induces changes in the morphology of the resonator (size and index of refraction), that in turn lead to a shift of the optical resonances (WGM). The optical resonances are typically excited using a single mode optical fiber. The preliminary analysis presented in this paper, shows that these sensors can measure energies of the order of 0.1J/m2.
{"title":"Room-temperature micro-photonic bolometer based on dielectric optical resonators","authors":"T. Ioppolo, E. Rubino","doi":"10.1117/12.2016303","DOIUrl":"https://doi.org/10.1117/12.2016303","url":null,"abstract":"In this paper we present a room-temperature micro-photonic bolometer that is based on the whispering gallery mode of dielectric resonator (WGM). The sensing element is a hollow micro-spherical optical polymeric resonator. The hollow resonator is filled with a fluid (gas or liquid) that has a large thermal expansion. When an incoming radiation impinges on the resonator is absorbed by the absorbing fluid leading to a thermal expansion of the micro-resonator. The thermal expansion induces changes in the morphology of the resonator (size and index of refraction), that in turn lead to a shift of the optical resonances (WGM). The optical resonances are typically excited using a single mode optical fiber. The preliminary analysis presented in this paper, shows that these sensors can measure energies of the order of 0.1J/m2.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121020734","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a method which combines with Bilateral Filter and cross cumulative residual entropy. It will be applied to infrared and visible registration. In this algorithm, firstly, according to infrared image and optical image characteristics, we put forward edge extraction algorithm based on the Bilateral Filter. Secondly, we use Cross Cumulative Residual Entropy (CCRE) as the similarity measure to match the reference images and transformed images effectively. Finally, we introduce the idea of calibration to reduce operation time. Bilateral filter can reduce noise and protect edge, and cross cumulative residual entropy uses cumulative distribution function instead of probability density function to overcome the noise on the local minima. The experiment proved that registration is effective.
{"title":"IR and visible images registration method based on cross cumulative residual entropy","authors":"Chaowei Li, Qian Chen, G. Gu, Tian Man","doi":"10.1117/12.2014267","DOIUrl":"https://doi.org/10.1117/12.2014267","url":null,"abstract":"This paper presents a method which combines with Bilateral Filter and cross cumulative residual entropy. It will be applied to infrared and visible registration. In this algorithm, firstly, according to infrared image and optical image characteristics, we put forward edge extraction algorithm based on the Bilateral Filter. Secondly, we use Cross Cumulative Residual Entropy (CCRE) as the similarity measure to match the reference images and transformed images effectively. Finally, we introduce the idea of calibration to reduce operation time. Bilateral filter can reduce noise and protect edge, and cross cumulative residual entropy uses cumulative distribution function instead of probability density function to overcome the noise on the local minima. The experiment proved that registration is effective.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127588368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yao O. Jin, Hitesh A. Basantani, Adem Ozcelik, Tom Jackson, M. Horn
Vanadium oxide (VOx) thin films have been intensively studied as an imaging material for uncooled microbolometers due to their low resistivity, high temperature coefficient of resistivity (TCR), and low 1/f noise. Our group has studied pulsed DC reactive sputtered VOx thin films while reactive ion beam sputtering has been exclusively used to fabricate the VOx thin films for commercial thermal imaging cameras. The typical resistivity of imaging-grade VOx thin films is in the range of 0.1 to 10 ohm-cm with a TCR from -2%/K to -3%/K. In this work, we report for the first time the use of a new biased target ion beam deposition tool to prepare vanadium oxide thin films. In this BTIBD system, ions with energy lower than 25ev are generated remotely and vanadium targets are negatively biased independently for sputtering. High TCR (<-4.5%/K) VOx thin films have been reproducibly prepared in the resistivity range of 103-104 ohm-cm by controlling the oxygen partial pressure using real-time control with a residual gas analyzer. These high resistivity films may be useful in next generation uncooled focal plane arrays for through film rather than lateral thermal resistors. This will improve the sensitivity through the higher TCR without increasing noise accompanied by higher resistance. We report on the processing parameters necessary to produce these films as well as details on how this novel deposition tool operates. We also report on controlled addition of alloy materials and their effects on VOx thin films’ electrical properties.
{"title":"High-resistivity and high-TCR vanadium oxide thin films for infrared imaging prepared by bias target ion-beam deposition","authors":"Yao O. Jin, Hitesh A. Basantani, Adem Ozcelik, Tom Jackson, M. Horn","doi":"10.1117/12.2016277","DOIUrl":"https://doi.org/10.1117/12.2016277","url":null,"abstract":"Vanadium oxide (VOx) thin films have been intensively studied as an imaging material for uncooled microbolometers due to their low resistivity, high temperature coefficient of resistivity (TCR), and low 1/f noise. Our group has studied pulsed DC reactive sputtered VOx thin films while reactive ion beam sputtering has been exclusively used to fabricate the VOx thin films for commercial thermal imaging cameras. The typical resistivity of imaging-grade VOx thin films is in the range of 0.1 to 10 ohm-cm with a TCR from -2%/K to -3%/K. In this work, we report for the first time the use of a new biased target ion beam deposition tool to prepare vanadium oxide thin films. In this BTIBD system, ions with energy lower than 25ev are generated remotely and vanadium targets are negatively biased independently for sputtering. High TCR (<-4.5%/K) VOx thin films have been reproducibly prepared in the resistivity range of 103-104 ohm-cm by controlling the oxygen partial pressure using real-time control with a residual gas analyzer. These high resistivity films may be useful in next generation uncooled focal plane arrays for through film rather than lateral thermal resistors. This will improve the sensitivity through the higher TCR without increasing noise accompanied by higher resistance. We report on the processing parameters necessary to produce these films as well as details on how this novel deposition tool operates. We also report on controlled addition of alloy materials and their effects on VOx thin films’ electrical properties.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"112 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122253641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Qin Wang, M. Rajabi, A. Karim, S. Almqvist, M. Bakowski, S. Savage, J. Andersson, M. Göthelid, Shun Yu, O. Gustafsson, M. Hammar, C. Asplund
Quantum structures base on type-II In(Ga)Sb quantum dots (QDs) embedded in an InAs matrix were used as active material for achieving long-wavelength infrared (LWIR) photodetectors in this work. Both InAs and In(Ga)Sb are narrow band semiconductor materials and known to possess a large number of surface states, which apparently play significant impact for the detector’s electrical and optical performance. These surface states are caused not only by material or device processing induced defects but also by surface dangling bonds, oxides, roughness and contaminants. To experimentally analyze the surface states of the QD structures treated by different device fabrication steps, atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) measurements were performed. The results were used to optimize the fabrication process of the LWIR photodetectors in our ongoing project. The dark current and its temperature dependence of the fabricated IR photodetectors were characterized in temperature range 10 K to 300 K, and the experiment results were analyzed by a theoretic modeling obtained using simulation tool MEDICI.
{"title":"Surface states characterization and simulation of Type-II In(Ga)Sb quantum dot structures for processing optimization of LWIR detectors","authors":"Qin Wang, M. Rajabi, A. Karim, S. Almqvist, M. Bakowski, S. Savage, J. Andersson, M. Göthelid, Shun Yu, O. Gustafsson, M. Hammar, C. Asplund","doi":"10.1117/12.2015966","DOIUrl":"https://doi.org/10.1117/12.2015966","url":null,"abstract":"Quantum structures base on type-II In(Ga)Sb quantum dots (QDs) embedded in an InAs matrix were used as active material for achieving long-wavelength infrared (LWIR) photodetectors in this work. Both InAs and In(Ga)Sb are narrow band semiconductor materials and known to possess a large number of surface states, which apparently play significant impact for the detector’s electrical and optical performance. These surface states are caused not only by material or device processing induced defects but also by surface dangling bonds, oxides, roughness and contaminants. To experimentally analyze the surface states of the QD structures treated by different device fabrication steps, atomic force microscopy (AFM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) measurements were performed. The results were used to optimize the fabrication process of the LWIR photodetectors in our ongoing project. The dark current and its temperature dependence of the fabricated IR photodetectors were characterized in temperature range 10 K to 300 K, and the experiment results were analyzed by a theoretic modeling obtained using simulation tool MEDICI.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"8704 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130428779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
S. Velghe, S. Magli, G. Aubry, N. Guerineau, S. Rommeluère, J. Jaeck, B. Wattellier
Recent developments in the Mid Wave InfraRed (MWIR) optical domain were made on materials, optical design and manufacturing. They answer increasing demands for more compact, less temperature dependent optical systems with increased optical performances and complexity (multi- or hyper- spectral imagery). At the same time, the characterization of these components has become strategic and requires solutions with higher performance. The optical quality of such devices is measured by wave front sensing techniques. PHASICS previously developed wave front sensors based on Quadri-Wave Lateral Shearing Interferometry (QWLSI) using broadband microbolometers cameras for infrared measurements. However they suffer from reduced light sensitivity in the MWIR domain, which limits their use with broadband sources such as black bodies. To meet metrology demands, we developed an innovative wave front sensor. This instrument combines the metrological qualities of QWLSI with the radiometric performances of a last generation detection block (Infrared Detector Dewar Cooler Assembly, IDDCA) with a quantum infrared focal plane array (IRFPA) of HgCdTe technology. The key component of QWLSI is a specific diffractive grating placed a few millimeters from the focal plane array. This requirement implies that this optics should be integrated inside the IDDCA. To achieve this, we take advantage of the experience acquired from recent developments with optics integrated in IDDCA. Thanks to this approach, we developed a high spatial resolution MWIR wave front sensor (160x128 points) with a high sensitivity for accurate measurements under low-flux conditions. This paper will present the instrument technological solutions, the development key steps and experimental results on various metrology applications.
{"title":"Dewar-cooler-integrated high sensitivity MWIR wave front sensor","authors":"S. Velghe, S. Magli, G. Aubry, N. Guerineau, S. Rommeluère, J. Jaeck, B. Wattellier","doi":"10.1117/12.2015905","DOIUrl":"https://doi.org/10.1117/12.2015905","url":null,"abstract":"Recent developments in the Mid Wave InfraRed (MWIR) optical domain were made on materials, optical design and manufacturing. They answer increasing demands for more compact, less temperature dependent optical systems with increased optical performances and complexity (multi- or hyper- spectral imagery). At the same time, the characterization of these components has become strategic and requires solutions with higher performance. The optical quality of such devices is measured by wave front sensing techniques. PHASICS previously developed wave front sensors based on Quadri-Wave Lateral Shearing Interferometry (QWLSI) using broadband microbolometers cameras for infrared measurements. However they suffer from reduced light sensitivity in the MWIR domain, which limits their use with broadband sources such as black bodies. To meet metrology demands, we developed an innovative wave front sensor. This instrument combines the metrological qualities of QWLSI with the radiometric performances of a last generation detection block (Infrared Detector Dewar Cooler Assembly, IDDCA) with a quantum infrared focal plane array (IRFPA) of HgCdTe technology. The key component of QWLSI is a specific diffractive grating placed a few millimeters from the focal plane array. This requirement implies that this optics should be integrated inside the IDDCA. To achieve this, we take advantage of the experience acquired from recent developments with optics integrated in IDDCA. Thanks to this approach, we developed a high spatial resolution MWIR wave front sensor (160x128 points) with a high sensitivity for accurate measurements under low-flux conditions. This paper will present the instrument technological solutions, the development key steps and experimental results on various metrology applications.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129817743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
D. Winters, P. Langehanenberg, J. Heinisch, E. Dumitrescu
The imaging quality of assembled optical systems is strongly influenced by the alignment errors of the individual lenses in the assembly. Although instrumentation for characterizing centering errors for the visual spectral range existed for some time, the technology to include the LWIR (8-12µm) and the MWIR (3-5µm) spectral ranges was only recently developed. Here, we report on the development and performance of such a measurement system that is capable of fully characterizing the alignment of all individual elements of an IR lens assembly in a non-contact and non-destructive fashion. The main component of the new instrument is an autocollimator working in the LWIR that determines the position of the center of curvature of each individual IR lens surface with respect to the instruments reference axis. This position data are used to calculate the shift and tilt of the individual lenses with respect to each other or a user-defined reference axis like e.g. the assembly housing. Finally, to complete the whole picture, the thicknesses and air gaps between individual lenses are measured with a low coherence interferometer built into the instrument. In order to obtain precise data, the instrument software takes the measured real centering error into account and directs the user to optimally align the assembly with respect of the interferometer reference axis, which then determines the position of the vertex positions along the optical axis and from these the center thicknesses of each lens and the air gaps between lenses with an accuracy below one micrometer.
{"title":"Precise opto-mechanical characterization of assembled infrared optics","authors":"D. Winters, P. Langehanenberg, J. Heinisch, E. Dumitrescu","doi":"10.1117/12.2015679","DOIUrl":"https://doi.org/10.1117/12.2015679","url":null,"abstract":"The imaging quality of assembled optical systems is strongly influenced by the alignment errors of the individual lenses in the assembly. Although instrumentation for characterizing centering errors for the visual spectral range existed for some time, the technology to include the LWIR (8-12µm) and the MWIR (3-5µm) spectral ranges was only recently developed. Here, we report on the development and performance of such a measurement system that is capable of fully characterizing the alignment of all individual elements of an IR lens assembly in a non-contact and non-destructive fashion. The main component of the new instrument is an autocollimator working in the LWIR that determines the position of the center of curvature of each individual IR lens surface with respect to the instruments reference axis. This position data are used to calculate the shift and tilt of the individual lenses with respect to each other or a user-defined reference axis like e.g. the assembly housing. Finally, to complete the whole picture, the thicknesses and air gaps between individual lenses are measured with a low coherence interferometer built into the instrument. In order to obtain precise data, the instrument software takes the measured real centering error into account and directs the user to optimally align the assembly with respect of the interferometer reference axis, which then determines the position of the vertex positions along the optical axis and from these the center thicknesses of each lens and the air gaps between lenses with an accuracy below one micrometer.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125055762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The development and implementation of wafer level packaging for commercial microbolometers has opened the pathway towards full wafer-based thermal imaging systems. The next challenge in development is moving from discrete element LWIR imaging systems to a wafer based optical system, similar to lens assemblies found in cell phone cameras. This paper will compare a typical high volume thermal imaging design manufactured from discrete lens elements to a similar design optimized for manufacture through a wafer based approach. We will explore both performance and cost tradeoffs as well as review the manufacturability of all designs.
{"title":"A practical approach to LWIR wafer-level optics for thermal imaging systems","authors":"Alan Symmons, R. Pini","doi":"10.1117/12.2015254","DOIUrl":"https://doi.org/10.1117/12.2015254","url":null,"abstract":"The development and implementation of wafer level packaging for commercial microbolometers has opened the pathway towards full wafer-based thermal imaging systems. The next challenge in development is moving from discrete element LWIR imaging systems to a wafer based optical system, similar to lens assemblies found in cell phone cameras. This paper will compare a typical high volume thermal imaging design manufactured from discrete lens elements to a similar design optimized for manufacture through a wafer based approach. We will explore both performance and cost tradeoffs as well as review the manufacturability of all designs.","PeriodicalId":338283,"journal":{"name":"Defense, Security, and Sensing","volume":"74 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2013-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115454220","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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