Monday, October 22, 2018

Image Sensor Imperfections

Caeleste has updated its 3-year old presentation "Imperfections of high-performance image sensors" by Bart Dierickx:

SPAD Quenching with 7.8ps Timing Jitter

MDPI Instruments publishes a paper "Quenching Circuit and SPAD Integrated in CMOS 65 nm with 7.8 ps FWHM Single Photon Timing Resolution" by Frédéric Nolet, Samuel Parent, Nicolas, Marc-Olivier Mercier, Serge A. Charlebois, Réjean Fontaine, and Jean-Francois Pratte, Université de Sherbrooke, Canada.

"This paper presents a new quenching circuit (QC) and single photon avalanche diode (SPAD) implemented in TSMC CMOS 65 nm technology. The QC was optimized for single photon timing resolution (SPTR) with a view to an implementation in a 3D digital SiPM. The presented QC has a timing jitter of 4 ps full width at half maximum (FWHM) and the SPAD and QC has a 7.8 ps FWHM SPTR. The QC adjustable threshold allows timing resolution optimization as well as SPAD excess voltage and rise time characterization. The adjustable threshold, hold-off and recharge are essential to optimize the performances of each SPAD. This paper also provides a better understanding of the different contributions to the SPTR. A study of the contribution of the SPAD excess voltage variation combined to the QC time propagation delay variation is presented. The proposed SPAD and QC eliminates the SPAD excess voltage contribution to the SPTR for excess voltage higher than 1 V due to its fixed time propagation delay."

Sunday, October 21, 2018

Saturday, October 20, 2018

Fujifilm Claims #1 Market Share in CFA

Fujifilm investor presentation claims #1 market share in CFA manufacturing:

Indeed, the company has a broad range of CFA materials:

Friday, October 19, 2018

AutoSens Brussels Interviews: Sony, ON Semi, More

AutoSens conference held in Brussels, Belgium, in September 2018, publishes a nice collection of interviews with its exhibitors:

Thursday, October 18, 2018

GF Securities on Smartphone Camera Trends, Apple ToF Solution

Hong Kong-based GF Securities publishes "Greater China Smartphone Supply Chain" report dated by Sept. 26, 2018. The analysts say about the forthcoming Apple ToF solution:

"Due to Apple’s AR focus (Apple launched its ARkit in June-2017), we expect ToF to be installed in Apple's 2019 iPhone models. However, due to VSCEL-based ToF not being ready due to issues in power consumption, sensor form factor, etc., our supply chain checks suggest a microwave RF solution is more likely. The solution uses an RF wavelength to detect depth and combines 2D/3D images captured by a dual-cam to deliver AR functions. Compared to VSCEL-based ToF, the RF solution has a lower cost but a lower resolution and shorter distance. We expect the microwave RF chip to be provided by either Apple or Broadcom."

There are few major trends with respect to the smartphone cameras:

"We forecast global tri-cam penetration in smartphones of 15% in 2019 (>200m units) and 25% in 2020... Concerns about low-spec “three individual” design make little sense to us, as tri-cam models mostly use optical zooms which require alignment. We also do not think algorithms will be able to replace tri-cams, as optical zooms cannot be achieved only using software.

Besides, we expect the trend of large sensors to continue, driven by Sony’s quadra sensor and Apple’s move to 1/2.6”/2.25” sensors in 2H18/2H19, from 1/2.8” in 2H17, lifting lens and module spec requirements. As such, we expect highend sensors and lenses to be in tight supply in 2019. For Largan, we expect its “new weapon”, pure black lenses, to help it gain traction in front cameras given its better full screen design.

For lens makers, we believe rising shipments driven by the robust tri-cam adoption should help alleviate competition and strengthen leading players’ pricing power. Spec-wise, due to tri-cam’s requirement for lens uniformity, we expect a duopoly in lenses – Largan to take the lion’s share while Sunny will benefit from order overflow. We believe it will be difficult for other second-tier lens makers to catch up.

For module makers, we believe the tri-cam trend should help to lift CCM ASPs, as a tri-cam module can carry a US$40+ ASP, compared to dual-cam modules at US$20+ for the current high-end Chinese OEM models. Regarding market concerns of the potential lower spec of the “three individual” design, we believe the design does not make sense for mid/high end models, which accounts for the majority of current tri-cam demand, as adding one additional camera mostly addresses the zoom function. We note that zoom functions require active alignment to calibrate optical performance; thus, we believe “two + one” makes more sense.

While the optical industry may not see a meaningful 7P upgrade in 2018-19, the previous yield issue on the P20 Pro suggests a high-end 6P design is still difficult for both lenses and modules due to the large CMOS sensor size. Theoretically, the large CMOS sensor size will challenge the z-height of modules and lenses. Based on our survey of CMOS roadmaps, we expect the trend of large sizes to continue, driven by Sony’s introduction of a quadra sensor and Apple’s move to larger sensors, both requiring high lens specs (i.e., thinner, higher frequency, etc.) and thinner module structures. P20 Pro’s 40MP lens is the first for quadra this year, and we expect OPPO, Xiaomi and Vivo to follow suit.

"Driven by the trend towards multi-cams and large CMOS sensors, our supply chain survey suggests leading CMOS sensor and lens makers will continue to expand capacity. However, we note that Sony, which hasn’t come out with official expansion guidance, looks slow in its expansion, and our supply chain survey suggests it may only have a 10-15% expansion plan for 2019. As such, we expect supply of high-end CMOS sensors and lenses (which mostly pair with Sony’s sensors) to be tight in 2019. We therefore expect a favorable pricing environment in 2019 for leading CMOS sensor and lens players."

Digitimes: CIS Demand to Boom in 2019

Digitimes expects the CMOS sensor demand to boom in 2019, thanks to triple-camera phones adoption and ADAS applications in 2019. After Huawei triple-camera in its P20 and Mate 20 series models, other China vendors are expected to follow, and even Apple is said to likely adopt thriple camera in its future iPhones.

Sony enjoys most of this mobile market growth. In addition, Sony is tapping into the supply chains of first-tier automotive suppliers such as Denso and Bosch, and is also zeroing in on the demand for rearview mirror CIS devices from Japan automakers such as Nissan, Honda and Toyota. Taiwan's backend service provider Kingpak is actively striving for packaging orders from Sony, the newspaper sources said.

Wednesday, October 17, 2018

Artilux Ge-on-Si ToF Pixel

IEDM publishes a teaser for Artilux paper "Ge-on-Si Lock-In Pixels for Distance Ranging" by N. Na et al.

"Range-imaging is key to many electronics applications such as hand tracking, facial recognition, localization/mapping for navigation, object detection/ranging for autonomous driving, and many others. However, new technologies are needed to enable accurate range-imaging at wavelengths beyond the visible range, in order to ensure eye safety and for better performance. One approach is to develop better “lock-in” pixels for use in image sensor arrays. Lock-in pixels provide distance information indirectly, using the time-of-flight (TOF) principle. TOF systems determine the distance of an object by shining light on it, reflecting that light to the pixel and noting when it arrives, and calculating the distance light would have traveled in that time. Artilux, Inc. researchers will report the first Ge-on-Si lock-in pixels for indirect TOF measurements for such uses. These Ge-on-Si pixels demonstrated both high sensitivity (quantum efficiency >85% and >46% at 940nm/1550nm wavelengths, respectively) and high resolution (demodulation contrast >0.81 at 300MHz), a significant improvement from their pure Si pixel counterparts. The technology may open new routes to high-performance indirect TOF sensors and imagers, as well as the potential adoption of eye-safe lasers for consumer electronics. The researchers say the lock-in pixels were fabricated using a commercially available foundry technology and hence may be ready for mass production in the near future."

Sony Maps its CIS Products

Sony publishes the maps explaining its image sensor lineups for consumer cameras and industrial applications: