A Time-of-Flight 3-D Image Sensor With Concentric-Photogates Demodulation Pixels

Lee, Tae-Yon; Lee, Yongjei; Min, Dong-Ki; Lee, Seung‐Hoon; Kim, Wanghyun; Jung, Jung-Kyu; Ovsiannikov, Ilia; Jin, Yu; Park, Yoondong; Fossum, Eric R.

doi:10.1109/ted.2014.2301875

Cited by 12 publications

(3 citation statements)

References 11 publications

(21 reference statements)

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“…Also, figure 3 reports as inset the Tauc's plot [27] (extrapolation of the linear portion of the plot of (E α film (E)) 2 versus photon energy E to intercept the energy axis) used to estimate The AC of (Cr:ITO_20) ITO shows reduced band-tailing with respect to ITO_20 and − (Cr:ITO_20) , a SiO 2 almost rapid rising-trend similar to ITO_80 and higher intensity than the absorption curves in figure 4. Since band-tailing effects are related to structural disorder inducing gap states close to the band-edges [28], the ML-method would indicate for (Cr: ITO_20) ITO improved order with respect to all the layers deposited on a-SiO 2 . Such statement is consistently supported by the following experimental evidences and observations.…”

Section: Example-application Of the Ml-method: Results And Discussionmentioning

confidence: 99%

Realistic absorption coefficient of each individual film in a multilayer architecture

Cesaria¹,

Caricato²,

Martino³

2015

J. Opt.

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A spectrophotometric strategy, termed multilayer-method (ML-method), is presented and discussed to realistically calculate the absorption coefficient of each individual layer embedded in multilayer architectures without reverse engineering, numerical refinements and assumptions about the layer homogeneity and thickness. The strategy extends in a non-straightforward way a consolidated route, already published by the authors and here termed basic-method, able to accurately characterize an absorbing film covering transparent substrates. The ML-method inherently accounts for non-measurable contribution of the interfaces (including multiple reflections), describes the specific film structure as determined by the multilayer architecture and used deposition approach and parameters, exploits simple mathematics, and has wide range of applicability (high-to-weak absorption regions, thick-to-ultrathin films). Reliability tests are performed on films and multilayers based on a well-known material (indium tin oxide) by deliberately changing the film structural quality through doping, thickness-tuning and underlying supporting-film. Results are found consistent with information obtained by standard (optical and structural) analysis, the basic-method and band gap values reported in the literature. The discussed example-applications demonstrate the ability of the ML-method to overcome the drawbacks commonly limiting an accurate description of multilayer architectures.

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Section: Example-application Of the Ml-method: Results And Discussionmentioning

confidence: 99%

Realistic absorption coefficient of each individual film in a multilayer architecture

Cesaria¹,

Caricato²,

Martino³

2015

J. Opt.

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“…Figs.5(a) and 5(b) show the charge modulators using photogate [8,30,44,45] and photogate with buried channel [14,15,25,46], respectively. Those structures are basically identical to the surface-and buried-channel CCDs.…”

Section: Charge-modulator-based Lock-in Pixelmentioning

confidence: 99%

Lock-in Pixel Based Time-of-Flight Range Imagers: An Overview

Yasutomi

Kawahito

2022

IEICE Trans. Electron.

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Time-of-flight (TOF) range imaging is a promising technology for various applications such as touchless control, augmented reality interface, and automotive. The TOF range imagers are classified into two methods: direct TOF with single photo avalanche diodes and indirect TOF with lock-in pixels. The indirect TOF range imagers have advantages in terms of a high spatial resolution and high depth precision because their pixels are simple and can handle many photons at one time. This paper reviews and discusses principal lock-in pixels reported both in the past and present, including circuit-based and charge-modulator-based lock-in pixels. In addition, key technologies that include enhancing sensitivity and background suppression techniques are also discussed.

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“…While these devices are a significant step forward for 3-D imaging, they suffer from their reliance on fast on-chip electronics to achieve high modulation frequencies. Currently, the best 3D imaging ToF devices on the market are based on photon mixing devices (PMD) and operate in the range of 20 -130 MHz modulation frequency [5,6]. This is particularly important for CW ToF systems, due to the depth resolution linearly scaling with the modulation frequency.…”

Section: Introductionmentioning

confidence: 99%

Open architecture time of flight 3D SWIR camera operating at 150 MHz modulation frequency

et al. 2017

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In the past two decades 3-D cameras have proven to be one of the next revolutions in machine vision. However, these devices are still an emerging technology with a particularly narrow set of commercially available devices. In this paper, the concept and execution of the first short wavelength infrared (SWIR) time-of-flight (ToF) 3-D camera system operating at a wavelength of 1550 nm is presented. By decoupling the optical and electrical components of the system in an open architecture we not only surpass many of the limitations of an on-chip integrated solution, but also can easily change the imaging device based on the requirements of the application. We achieve modulation frequencies up to 150 MHz, which exceeds the conventional values currently published for other large format modulators by about five times. This increase in the modulation frequency allows for a TOF camera with significantly higher depth resolution, while the open architecture design allows for a highly reconfigurable device that can be modified for specific working conditions.

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A Time-of-Flight 3-D Image Sensor With Concentric-Photogates Demodulation Pixels

Cited by 12 publications

References 11 publications

Realistic absorption coefficient of each individual film in a multilayer architecture

Realistic absorption coefficient of each individual film in a multilayer architecture

Lock-in Pixel Based Time-of-Flight Range Imagers: An Overview

Open architecture time of flight 3D SWIR camera operating at 150 MHz modulation frequency

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