Novel fingerprint scanning arrays using polysilicon TFT's on glass and polymer substrates

Young, N. D.; Harkin, G.; Bunn, R.M.; McCulloch, D.J.; Wilks, Richard W.; Knapp, Alfred

doi:10.1109/55.553063

Cited by 126 publications

(47 citation statements)

References 6 publications

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“…Polysilicon field effect transistors (FETs) are the technology of choice in a number of large-area electronic applications, including flat-panel display/touch screens [1], fingerprint readers [2] and logic circuits [3]. Due to the high mobility of polycrystalline silicon [3,4], electronic devices and circuits made with this material operate at high frequencies and have larger current densities in their "on" state when compared to those made with other thin-film technologies, such as hydrogenated amorphous silicon or amorphous carbon.…”

Section: Introductionmentioning

confidence: 99%

Field Plate Optimization in Low-Power High-Gain Source-Gated Transistors

Sporea

Trainor

Young

et al. 2012

IEEE Trans. Electron Devices

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-Source-gated transistors (SGTs) have potentially very high output impedance and low saturation voltages, which make them ideal as building blocks for high performance analog circuits fabricated in thin-film technologies. The quality of the saturation is greatly influenced by the design of the field-relief structure incorporated into the source electrode. Starting from measurements on self-aligned polysilicon structures, we show through numerical simulations how the field plate design can be improved. A simple source field plate around 1µm long situated several tens of nm above the semiconductor can increase the low-voltage intrinsic gain by more than two orders of magnitude and offers adequate tolerance to process variations in a moderately scaled thin-film SGT.

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Section: Introductionmentioning

confidence: 99%

Field Plate Optimization in Low-Power High-Gain Source-Gated Transistors

Sporea

Trainor

Young

et al. 2012

IEEE Trans. Electron Devices

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“…Cross sections of the orginal (bold) and reconstructed object (dashed) 3D object from edge capacitance data with multiple transmitters. A and B: using (13), C and D: using (14) parameter in the deformation of the guess and 3) by the stopping criterion. We have shown that a simplification can be made to the minimization functional, which yields similar reconstruction results but makes the numerical execution three times faster.…”

Section: Discussionmentioning

confidence: 99%

“…It is also important to point out that there are capacitance measurements in which the load capacitance to single electrodes is measured [14,15,16]. These techniques also aim to create an 'image' of a remote object but in the vocabulary of this paper, this image is the sum of multiple c(x), each one sampled at the just point, the position of the corresponding transmitter.…”

Section: The Inverse Problemmentioning

confidence: 99%

An iterative method for electrostatic object reconstruction in a half space

Berkel¹,

Lionheart²

2006

Meas. Sci. Technol.

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Abstract. Sensing electrodes arranged in or around a display can provide input function for interactive displays. Commercially this is interesting because the sensing electrodes and electronics can be made in the same manufacturing process as that of the display itself thus reducing cost. In engineering terms the electrodes measure capacitance changes resulting from the presence and movement of objects such as hands and fingers in front of the display. At the quasi static frequencies used (100kHz) the human body is conductive and the hands or fingers provide a screen between the capacitive electrodes. There is no need to touch the actual display and the overall system constitutes a touchless gesture input system.Determining the shape of the hand or fingers is a boundary condition reconstruction problem of finding the boundary of an earthed conductive object D from electrostatic measurements. This is the ill-posed problem of recovering the zero-surface of a solution to Laplace's equation from Cauchy data on part of the boundary of a domain. The problem has similarities with object reconstruction in EIT or inverse scattering but is complicated because only a partial Dirichelet-Neumannn map is available as experimental data.We suggest an algorithm where at each iteration we have an approximation ∂D k to ∂D on which we calculate approximate Cauchy data by solving a Tikhonov regularized linear system. This data is used to modify ∂D k by extrapolation towards the zero-surface giving the next approximation ∂D k+1 .We implemented the algorithm in two and three space dimensions using the Boundary Element Method for discretization. Numerical results using simulated data with added noise show that simply connected but not necessarily convex objects can be reconstructed with reasonable positional accuracy and approximate shape, but as might be expected the shape is more accurately determined near the plane of measurements.

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“…Several groups have followed the challenging target to use low-cost polymer substrates, in spite of the more stringent limitations on the maximum processing temperatures, starting from the seminal work by N. D. Young at Philips Res. Lab (UK) [12,13] and followed by the groups at Lawrence Livermore National Lab. [14], Sony [15], Electronics and Telecommunications Research Institute (ETRI) [16][17][18], Samsung Advanced Institute of Technology (SAIT) [19][20][21], Korea Electronics Technology Institute (KETI) [22,23] and at University of Rennes [24,25], ultra-low-temperature polycrystalline silicon (ULTPS) devices were demonstrated.…”

Section: Methodsmentioning

confidence: 99%