Digital Image Sensor Evolution and New Frontiers.

This article reviews nearly 60 years of solid-state image sensor evolution and identifies potential new frontiers in the field. From early work in the 1960s, through the development of charge-coupled device image sensors, to the complementary metal oxide semiconductor image sensors now ubiquitous in our lives, we discuss highlights in the evolutionary chain. New frontiers, such as 3D stacked technology, photon-counting technology, and others, are briefly discussed.

Pixel-wise programmability enables dynamic high-SNR cameras for high-speed microscopy.

High-speed wide-field fluorescence microscopy has the potential to capture biological processes with exceptional spatiotemporal resolution. However, conventional cameras suffer from low signal-to-noise ratio at high frame rates, limiting their ability to detect faint fluorescent events. Here, we introduce an image sensor where each pixel has individually programmable sampling speed and phase, so that pixels can be arranged to simultaneously sample at high speed with a high signal-to-noise ratio.

Design and Characterization of a Burst Mode 20 Mfps Low Noise CMOS Image Sensor.

This paper presents a novel ultra-high speed, high conversion-gain, low noise CMOS image sensor (CIS) based on charge-sweep transfer gates implemented in a standard 180 nm CIS process. Through the optimization of the photodiode geometry and the utilization of charge-sweep transfer gates, the proposed pixels achieve a charge transfer time of less than 10 ns without requiring any process modifications. Moreover, the gate structure significantly reduces the floating diffusion capacitance, resulting in an increased conversion gain of 183 µV/-.

Pixel-wise programmability enables dynamic high-SNR cameras for high-speed microscopy.

High-speed wide-field fluorescence microscopy has the potential to capture biological processes with exceptional spatiotemporal resolution. However, conventional cameras suffer from low signal-to-noise ratio at high frame rates, limiting their ability to detect faint fluorescent events. Here, we introduce an image sensor where each pixel has individually programmable sampling speed and phase, so that pixels can be arranged to simultaneously sample at high speed with a high signal-to-noise ratio.

Threshold Uniformity Improvement in 1b Quanta Image Sensor Readout Circuit.

A new readout architecture for single-bit quanta image sensor (QIS) consisting of a capacitive transimpedance amplifier (CTIA) before a 1-bit quantizer to improve the threshold uniformity of the readout cluster is proposed in this paper. The 1-bit quantizer in the previous single-bit QIS had significant threshold non-uniformity likely caused by the fluctuation of the common-mode voltage of the jot output. To guarantee the stability of the common-mode voltage of input signals fed to the 1-bit quantizer, the CTIA is added before the 1-bit quantizer.

Simulating 50 keV X-ray Photon Detection in Silicon with a Down-Conversion Layer.

Simulation results are presented that explore an innovative, new design for X-ray detection in the 20-50 keV range that is an alternative to traditional direct and indirect detection methods. Typical indirect detection using a scintillator must trade-off between absorption efficiency and spatial resolution. With a high-Z layer that down-converts incident photons on top of a silicon detector, this design has increased absorption efficiency without sacrificing spatial resolution.

Billion-pixel x-ray camera (BiPC-X).

The continuing improvement in quantum efficiency (above 90% for single visible photons), reduction in noise (below 1 electron per pixel), and shrink in pixel pitch (less than 1 μm) enable billion-pixel x-ray cameras (BiPC-X) based on commercial complementary metal-oxide-semiconductor (CMOS) imaging sensors. We describe BiPC-X designs and prototype construction based on flexible tiling of commercial CMOS imaging sensors with millions of pixels. Device models are given for direct detection of low energy x rays (<10 keV) and indirect detection of higher energies using scintillators.

1/ Noise Modelling and Characterization for CMOS Quanta Image Sensors.

This work fits the measured in-pixel source-follower noise in a CMOS Quanta Image Sensor (QIS) prototype chip using physics-based 1/ noise models, rather than the widely-used fitting model for analog designers. This paper discusses the different origins of 1/ noise in QIS devices and includes correlated double sampling (CDS). The modelling results based on the Hooge mobility fluctuation, which uses one adjustable parameter, match the experimental measurements, including the variation in noise from room temperature to -70 °C.

Non-avalanche single photon detection without carrier transit-time delay through quantum capacitive coupling.

Searching for innovative approaches to detect single photons remains at the center of science and technology for decades. This paper proposes a zero transit-time, non-avalanche quantum capacitive photodetector to register single photons. In this detector, the absorption of a single photon changes the wave function of a single electron trapped in a quantum dot (QD), leading to a charge density redistribution nearby.

The Quanta Image Sensor: Every Photon Counts.

The Quanta Image Sensor (QIS) was conceived when contemplating shrinking pixel sizes and storage capacities, and the steady increase in digital processing power. In the single-bit QIS, the output of each field is a binary bit plane, where each bit represents the presence or absence of at least one photoelectron in a photodetector. A series of bit planes is generated through high-speed readout, and a kernel or "cubicle" of bits (x, y, t) is used to create a single output image pixel.

Application of the Quanta image sensor concept to linear polarization imaging-a theoretical study.

Research efforts in linear polarization imaging have largely targeted the development of novel polarizing filters with improved performance and the monolithic integration of image sensors and polarization filter arrays. However, as pixel sizes in CMOS image sensors continue to decrease, the same limitations that have an impact on color and monochrome CMOS image sensors will undoubtedly affect polarization imagers. Issues of low signal capacity and dynamic range in small pixels will severely limit the useful polarization information that can be obtained.

Quantum Random Number Generation Using a Quanta Image Sensor.

A new quantum random number generation method is proposed. The method is based on the randomness of the photon emission process and the single photon counting capability of the Quanta Image Sensor (QIS). It has the potential to generate high-quality random numbers with remarkable data output rate.

Color filter array patterns for small-pixel image sensors with substantial cross talk.

Digital image sensor outputs usually must be transformed to suit the human visual system. This color correction amplifies noise, thus reducing the signal-to-noise ratio (SNR) of the image. In subdiffraction-limit (SDL) pixels, where optical and carrier cross talk can be substantial, this problem can become significant when conventional color filter arrays (CFAs) such as the Bayer patterns (RGB and CMY) are used.

3,5-Difluoro-phenyl phenyl sulfone.

In the title compound, C(12)H(8)F(2)O(2)S, which is a precursor of functionalised poly(aryl-ene ether sulfone) polymers, the dihedral angle between the aromatic ring planes is 84.43 (8)°. In the crystal structure, aromatic π-π stacking [centroid-centroid separations = 3.