Tuesday, December 12, 2017

MEMSDrive OIS vs. VCM-based OIS

MEMSDrive publishes comparison videos of its OIS against iPhone X and Galaxy Note8 VCM-based OIS:

IEDM Papers Review

Semiconductor Engineering publishes Mark Lapedus review of IEDM 2017 Imaging Session papers:

- TSMC and EPFL presented "a paper on what they call the world’s first back-illuminated 3D-stacked, single-photon avalanche diode (SPAD) in 45nm CMOS technology.

The SPAD achieves a dark count rate of 55.4cps/μm2, a maximum photon detection probability of 31.8% at 600nm, over 5% in the 420-920nm wavelength range, and timing jitter of 107.7ps at 2.5V excess bias voltage at room temperature.

- Sony presented "a paper on a CMOS photon detector - a non-electron-multiplying CMOS image sensor photon detector. Based on a 90nm process, Sony’s CMOS photon detector features 15μm pitch active sensor pixels with a complete charge transfer and readout noise of 0.5 e- RMS.

The pixel circuit is a conventional 4T pixel. The pixels are arrayed, resulting in a high conversion gain of 132uV/e-, according to the paper. The photodiode is expanded to a size of 14.7μm x 13.1μm in a pixel with a pitch of 15μm, resulting in a physical fill factor of 76% without using back illumination. 4 pixels in a column are simultaneously accessed and read.

Samsung Improves its Iris Scanner

Korea Herald: The oncoming "Galaxy S9’s iris scanner will have an improved camera lens and functions to make it better to recognize the eyes of users.

The iris camera lens will be improved to 3MP from 2MP of Galaxy S8 and Galaxy Note 8 to capture clearer images. The scanner will better recognize users’ irises even when they wear eyeglasses, move their eyeballs or are in a too dark or too light environment. The response time will also be shorter from the current one second.

Samsung is also on target to expand the iris scanner into budget models possibly late next year or early 2019 with the ultimate aim of replacing physical banks with mobile banking.

A Samsung spokesperson said, “Iris scanner is the safest biometric authentication (among iris, fingerprint and face recognition) and we will continue to improve the system for upcoming smartphones for safer banking transactions.

Galaxy S8 iris scanning

MIPI Alliance Opens Access to its MIPI I3C Sensor Interface Specification

BusinessWire: Starting today, all companies, including those not currently members of MIPI Alliance, may access the MIPI I3C v1.0 specification so they may evaluate the incorporation of the specification into their sensor integration plans and design applications.

MIPI I3C provides a welcome update to the I2C technology that has been widely adopted over the past 35 years. Extending access provides an opportunity to spur innovation and help other industries beyond mobile," said Joel Huloux, chairman of MIPI Alliance. "It helps MIPI members as well, because it supports greater adoption and interoperability, strengthens the ecosystem and provides for a richer development environment.

Panasonic and Osaka University Develop Blood Vessel Endoscope

Asahi Shimbun: Panasonic and Osaka University have developed what they say is the world’s first vascular endoscopic catheter with an image sensor on its head that they say greatly improves blood vessel observations and could change existing therapies. The new catheter has a color resolution of about 480,000 pixels, about 50x higher than the existing devices.

An image sensor, a lens and a fiber-optic illuminator are embedded in the head of the vascular endoscopic catheter, which measures 1.8mm across and 5mm long.

Taisho Biomed Instruments Co., a manufacturer of medical devices, plans to release the new vascular endoscopic catheter for sale to hospitals this year. Panasonic has set a shipping target of about 8,000 units in fiscal 2021.

Synaptics Unveils 2nd Generation Under-display Optical Fingerprint Sensor

PC Perspective: Synaptics unveils FS9500 Clear ID family of optical fingerprint sensors for smartphones with OLED displays. Synaptics attaches a fingerprint senor module to the underside of the display and using the OLED display itself as the light source to illuminate the user's fingerprint so that the optimized CMOS image sensor can scan the fingerprint from the reflected light bounced through the gaps in between pixels. The new sensor can work with up to 1.5mm-thick displays.

Synaptics uses "Quantum Matcher" and "PurePrint" machine learning technology to enhance security and adapts to different external lighting environments, including a direct sunlight. The company says that its new fingerprint sensor is able to work faster and in more situations than a 3D facial recognition systems: its fingerprint sensor is able to read a user's fingerprint in 0.7s versus 1.4s for a facial recognition camera. The Clear ID In-Display fingerprint sensor is said to have approximately 99% spoof rejection rate due to the AI-powered PurePrint technology that discerns real fingerprints from fakes.

GlobeNewsWire: Synaptics is said to bring its in-display fingerprint sensors to mass production with one of the top five OEMs.

GlobeNewsWire: Synaptics's previous generation Natural ID FS9100 family of optical-based, under-glass fingerprint authentication solutions have been named a CES 2018 Innovation Awards Honoree. The Natural ID FS9100 family is said to be the industry’s first optical-based fingerprint sensors for smartphones enabling secure authentication through 1mm thick cover glass.

Synaptics is currently sampling its third-generation optical solution for in-display fingerprint authentication to select customers with mass production with a Tier 1 OEM expected in the current calendar year.

Monday, December 11, 2017

12nm Pixel Size

There is a funny mistake in Xiaomi Redmi 5 Plus smartphone promotional video:

2-step Column-Parallel Delta-Sigma ADC

CentraleSupelec, France, publishes a paper "A 14-b Two-step Inverter-based Σ∆ ADC for CMOS Image Sensor" by Pierre Bisiaux, Caroline Lelandais-Perrault, Anthony Kolar, Philippe Benabes, and Filipe Vinci dos Santos presented at IEEE International NEWCAS Conference, in June 2017 at Strasbourg, France.

"This paper presents a 14-bit Incremental Sigma Delta (IΣ∆) analog-to-digital converter (ADC) suitable for a column wise integration in a CMOS image sensor. A two-step conversion is performed to improve the conversion speed. As the same Σ∆ modulator is used for both steps, the overall complexity is reduced. Furthermore, the use of inverter-based amplifiers instead of operational transconductance amplifier (OTA) facilitates the integration within the column pitch and decreases power consumption. The proposed ADC is designed in 0.18 µm CMOS technology. The simulation shows that for a 1.8 V voltage supply, a 20 MHz clock frequency and an oversampling ratio (OSR) of 70, the power consumption is 460 µW, achieving an SNR of 83.7 dB."

Sunday, December 10, 2017

Imec Quantum Dot Sensor

MDPI Special Issue on the 2017 International Image Sensor Workshop (IISW) publishes Imec, KU Leuven, and Ghent University paper "Thin-Film Quantum Dot Photodiode for Monolithic Infrared Image Sensors" by Pawel E. Malinowski, Epimitheas Georgitzikis, Jorick Maes, Ioanna Vamvaka, Fortunato Frazzica, Jan Van Olmen, Piet De Moor, Paul Heremans, Zeger Hens, and David Cheyns. The paper describes a somewhat similar to Invisage IR image sensor:

"This work describes a CMOS-compatible pixel stack based on lead sulfide quantum dots (PbS QD) with tunable absorption peak. Photodiode with a 150-nm thick absorber in an inverted architecture shows dark current of 10−6 A/cm2 at −2 V reverse bias and EQE above 20% at 1440 nm wavelength. Optical modeling for top illumination architecture can improve the contact transparency to 70%. Additional cooling (193 K) can improve the sensitivity to 60 dB. This stack can be integrated on a CMOS ROIC, enabling order-of-magnitude cost reduction for infrared sensors."

Saturday, December 09, 2017

Canon Global Shutter Sensor Paper

MDPI Special Issue on the 2017 International Image Sensor Workshop (IISW) publishes Canon paper "Development of Gentle Slope Light Guide Structure in a 3.4 μm Pixel Pitch Global Shutter CMOS Image Sensor with Multiple Accumulation Shutter Technology" by Hiroshi Sekine, Masahiro Kobayashi, Yusuke Onuki, Kazunari Kawabata, Toshiki Tsuboi, Yasushi Matsuno, Hidekazu Takahashi, Shunsuke Inoue, and Takeshi Ichikawa.

"CISs with GS function have generally been inferior to the rolling shutter (RS) CIS in performance, because they have more components. This problem is remarkable in small pixel pitch. The newly developed 3.4 µm pitch GS CIS solves this problem by using multiple accumulation shutter technology and the gentle slope light guide structure. As a result, the developed GS pixel achieves 1.8 e− temporal noise and 16,200 e− full well capacity with charge domain memory in 120 fps operation. The sensitivity and parasitic light sensitivity are 28,000 e−/lx·s and −89 dB, respectively. Moreover, the incident light angle dependence of sensitivity and parasitic light sensitivity are improved by the gentle slope light guide structure."