scholarly journals Toward the Ultimate-High-Speed Image Sensor: From 10 ns to 50 ps

Sensors ◽  
2018 ◽  
Vol 18 (8) ◽  
pp. 2407 ◽  
Author(s):  
Anh Nguyen ◽  
Vu Dao ◽  
Kazuhiro Shimonomura ◽  
Kohsei Takehara ◽  
Takeharu Etoh
Keyword(s):  
Temporal Resolution ◽  
High Speed ◽  
Image Sensor ◽  
Image Sensors ◽  
Frame Rate ◽  
Resolution Limit ◽  
Performance Indices ◽  
Theoretical Limit ◽  
Theoretical Derivation ◽  
Trade Offs

The paper summarizes the evolution of the Backside-Illuminated Multi-Collection-Gate (BSI MCG) image sensors from the proposed fundamental structure to the development of a practical ultimate-high-speed silicon image sensor. A test chip of the BSI MCG image sensor achieves the temporal resolution of 10 ns. The authors have derived the expression of the temporal resolution limit of photoelectron conversion layers. For silicon image sensors, the limit is 11.1 ps. By considering the theoretical derivation, a high-speed image sensor designed can achieve the frame rate close to the theoretical limit. However, some of the conditions conflict with performance indices other than the frame rate, such as sensitivity and crosstalk. After adjusting these trade-offs, a simple pixel model of the image sensor is designed and evaluated by simulations. The results reveal that the sensor can achieve a temporal resolution of 50 ps with the existing technology.

scholarly journals Light-In-Flight Imaging by a Silicon Image Sensor: Toward the Theoretical Highest Frame Rate

Sensors ◽  
2019 ◽  
Vol 19 (10) ◽  
pp. 2247 ◽  
Author(s):  
Takeharu Etoh ◽  
Tomoo Okinaka ◽  
Yasuhide Takano ◽  
Kohsei Takehara ◽  
Hitoshi Nakano ◽  
...  
Keyword(s):  
Temporal Resolution ◽  
High Speed ◽  
Streak Camera ◽  
Image Sensor ◽  
Pulse Neutron ◽  
Frame Rate ◽  
Neutron Tomography ◽  
Single Shot ◽  
Resolution Limit ◽  
Lifetime Measurements

Light in flight was captured by a single shot of a newly developed backside-illuminated multi-collection-gate image sensor at a frame interval of 10 ns without high-speed gating devices such as a streak camera or post data processes. This paper reports the achievement and further evolution of the image sensor toward the theoretical temporal resolution limit of 11.1 ps derived by the authors. The theoretical analysis revealed the conditions to minimize the temporal resolution. Simulations show that the image sensor designed following the specified conditions and fabricated by existing technology will achieve a frame interval of 50 ps. The sensor, 200 times faster than our latest sensor will innovate advanced analytical apparatuses using time-of-flight or lifetime measurements, such as imaging TOF-MS, FLIM, pulse neutron tomography, PET, LIDAR, and more, beyond these known applications.

scholarly journals Toward the Super Temporal Resolution Image Sensor with a Germanium Photodiode for Visible Light

Sensors ◽  
2020 ◽  
Vol 20 (23) ◽  
pp. 6895
Author(s):  
Nguyen Hoai Ngo ◽  
Anh Quang Nguyen ◽  
Fabian M. Bufler ◽  
Yoshinari Kamakura ◽  
Hideki Mutoh ◽  
...  
Keyword(s):  
Visible Light ◽  
Temporal Resolution ◽  
High Speed ◽  
Image Sensor ◽  
Propagation Time ◽  
Resolution Limit ◽  
Silicon Photodiode ◽  
Driver Circuit ◽  
Practical Limit ◽  
Better Than

The theoretical temporal resolution limit tT of a silicon photodiode (Si PD) is 11.1 ps. We call “super temporal resolution” the temporal resolution that is shorter than that limit. To achieve this resolution, Germanium is selected as a candidate material for the photodiode (Ge PD) for visible light since the absorption coefficient of Ge for the wavelength is several tens of times higher than that of Si, allowing a very thin PD. On the other hand, the saturation drift velocity of electrons in Ge is about 2/3 of that in Si. The ratio suggests an ultra-short propagation time of electrons in the Ge PD. However, the diffusion coefficient of electrons in Ge is four times higher than that of Si. Therefore, Monte Carlo simulations were applied to analyze the temporal resolution of the Ge PD. The estimated theoretical temporal resolution limit is 0.26 ps, while the practical limit is 1.41 ps. To achieve a super temporal resolution better than 11.1 ps, the driver circuit must operate at least 100 GHz. It is thus proposed to develop, at first, a short-wavelength infrared (SWIR) ultra-high-speed image sensor with a thicker and wider Ge PD, and then gradually decrease the size along with the progress of the driver circuits.

Amorphous Silicon Image Sensor Arrays

1992 ◽  
Vol 258 ◽  
Author(s):  
M J Powell ◽  
I D French ◽  
J R Hughes ◽  
N C Bird ◽  
O S Davies ◽  
...  
Keyword(s):  
Amorphous Silicon ◽  
High Speed ◽  
Dynamic Range ◽  
Sensor Arrays ◽  
Image Sensor ◽  
Low Noise ◽  
Image Sensors ◽  
Frame Rate ◽  
Intimate Contact ◽  
Current Densities

ABSTRACTWe have developed a technology for 2D matrix-addressed image sensors using amorphous silicon photodiodes and thin film transistors. We have built a small prototype, having 192×192 pixels with a 20μm pixel pitch, and assessed its performance. The nip photodiodes can have dark current densities of less than 1011 A.cm-2 (up to 5V reverse bias) and peak quantum efficiencies of 88% (at 580nm). We operated the sensor in real time mode at high speed (50 Hz frame rate and 64μS line time). The image sensor has a low noise performance giving a dynamic range in excess of 104. The maximum crosstalk is about 2%, which allows at least 50 grey levels. The bottom contact of the photodiode acts as a light shield from light through the substrate, which enables the sensor to be operated as an intimate contact image sensor to image a document placed directly on top of the array. In this mode, the CTF was 75% at 2 lp.mm1. Good quality images are demonstrated in both front projection and intimate contact imaging modes.

scholarly journals On-CMOS Image Sensor Processing for Lane Detection

Sensors ◽  
2021 ◽  
Vol 21 (11) ◽  
pp. 3713
Author(s):  
Soyeon Lee ◽  
Bohyeok Jeong ◽  
Keunyeol Park ◽  
Minkyu Song ◽  
Soo Youn Kim
Keyword(s):  
Edge Detection ◽  
High Speed ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Image Resolution ◽  
Lane Detection ◽  
Frame Rate ◽  
Total Power ◽  
Detection Accuracy ◽  
Total Power Consumption

This paper presents a CMOS image sensor (CIS) with built-in lane detection computing circuits for automotive applications. We propose on-CIS processing with an edge detection mask used in the readout circuit of the conventional CIS structure for high-speed lane detection. Furthermore, the edge detection mask can detect the edges of slanting lanes to improve accuracy. A prototype of the proposed CIS was fabricated using a 110 nm CIS process. It has an image resolution of 160 (H) × 120 (V) and a frame rate of 113, and it occupies an area of 5900 μm × 5240 μm. A comparison of its lane detection accuracy with that of existing edge detection algorithms shows that it achieves an acceptable accuracy. Moreover, the total power consumption of the proposed CIS is 9.7 mW at pixel, analog, and digital supply voltages of 3.3, 3.3, and 1.5 V, respectively.

scholarly journals Design of an Edge-Detection CMOS Image Sensor with Built-in Mask Circuits

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3649
Author(s):  
Minhyun Jin ◽  
Hyeonseob Noh ◽  
Minkyu Song ◽  
Soo Youn Kim
Keyword(s):  
Power Consumption ◽  
Edge Detection ◽  
Low Power ◽  
High Speed ◽  
Cmos Image Sensor ◽  
Image Sensor ◽  
Frame Rate ◽  
Oxide Semiconductor ◽  
Total Power ◽  
Total Power Consumption

In this paper, we propose a complementary metal-oxide-semiconductor (CMOS) image sensor (CIS) that has built-in mask circuits to selectively capture either edge-detection images or normal 8-bit images for low-power computer vision applications. To detect the edges of images in the CIS, neighboring column data are compared in in-column memories after column-parallel analog-to-digital conversion with the proposed mask. The proposed built-in mask circuits are implemented in the CIS without a complex image signal processer to obtain edge images with high speed and low power consumption. According to the measurement results, edge images were successfully obtained with a maximum frame rate of 60 fps. A prototype sensor with 1920 × 1440 resolution was fabricated with a 90-nm 1-poly 5-metal CIS process. The area of the 4-shared 4T-active pixel sensor was 1.4 × 1.4 µm2, and the chip size was 5.15 × 5.15 mm2. The total power consumption was 9.4 mW at 60 fps with supply voltages of 3.3 V (analog), 2.8 V (pixel), and 1.2 V (digital).

scholarly journals Ultrafast optical imaging technology: principles and applications of emerging methods

Nanophotonics ◽  
2016 ◽  
Vol 5 (4) ◽  
pp. 497-509 ◽  
Author(s):  
Hideharu Mikami ◽  
Liang Gao ◽  
Keisuke Goda
Keyword(s):  
Optical Imaging ◽  
High Speed ◽  
Image Sensors ◽  
Frame Rate ◽  
High Temporal Resolution ◽  
New Class ◽  
Advantages And Disadvantages ◽  
Ultrafast Optical ◽  
Small Field Of View ◽  
Shutter Speed

AbstractHigh-speed optical imaging is an indispensable technology for blur-free observation of fast transient dynamics in virtually all areas including science, industry, defense, energy, and medicine. High temporal resolution is particularly important for microscopy as even a slow event appears to occur “fast” in a small field of view. Unfortunately, the shutter speed and frame rate of conventional cameras based on electronic image sensors are significantly constrained by their electrical operation and limited storage. Over the recent years, several unique and unconventional approaches to high-speed optical imaging have been reported to circumvent these technical challenges and achieve a frame rate and shutter speed far beyond what can be reached with the conventional image sensors. In this article, we review the concepts and principles of such ultrafast optical imaging methods, compare their advantages and disadvantages, and discuss an entirely new class of applications that are possible using them.

Electrical Properties of Ga2O3:Sn/CIGS Hetero-junction

2014 ◽  
Vol 1603 ◽  
Author(s):  
Kenji Kikuchi ◽  
Shigeyuki Imura ◽  
Kazunori Miyakawa ◽  
Misao Kubota ◽  
Eiji Ohta
Keyword(s):  
Thin Film ◽  
Visible Light ◽  
Dark Current ◽  
Carrier Density ◽  
High Speed ◽  
Depletion Region ◽  
Image Sensors ◽  
Frame Rate ◽  
Semiconductor Layer ◽  
High Quantum Efficiency

ABSTRACTThere is an increased need for highly sensitive imaging devices to develop high resolution and high speed image sensors. Incident light intensity per pixel of image sensors is getting lower because the pixel resolution and frame rate of image sensors are becoming higher. We investigated the feasibility of using a photoconductor with tin-doped gallium oxide (Ga2O3:Sn)/Cu(In,Ga)Se2 (CIGS) hetero-junction for visible light image sensors. CIGS chalcopyrite thin films have great potential for improving the sensitivity of image sensors and CIGS chalcopyrite semiconductors have both a high absorption coefficient and high quantum efficiency. Moreover, the band gap can be adjusted for visible light. We applied Ga2O3 as an n-type semiconductor layer and a hole-blocking layer to CIGS thin film to reduce the dark current. The experimental results revealed that dark current was drastically reduced due to the application of Ga2O3 thin film, and an avalanche multiplication phenomenon was observed at an applied voltage of over 6 V. However, non-doped Ga2O3/CIGS hetero-junction only had sensitivity in the ultraviolet light region because their depletion region was almost completely spread throughout the Ga2O3 layer due to the low carrier density of the Ga2O3 layer. Therefore, we used Ga2O3:Sn for the n-type layer to increase carrier density. As a result, the depletion region shifted to the CIGS film and the cells had sensitivity in all visible regions. These results indicate that Ga2O3:Sn/CIGS hetero-junction are feasible for visible light photoconductors.

scholarly journals An Image Signal Accumulation Multi-Collection-Gate Image Sensor Operating at 25 Mfps with 32 × 32 Pixels and 1220 In-Pixel Frame Memory

Sensors ◽  
2018 ◽  
Vol 18 (9) ◽  
pp. 3112 ◽  
Author(s):  
Vu Dao ◽  
Nguyen Ngo ◽  
Anh Nguyen ◽  
Kazuhiro Morimoto ◽  
Kazuhiro Shimonomura ◽  
...  
Keyword(s):  
High Speed ◽  
Motion Pictures ◽  
High Sensitivity ◽  
Image Sensor ◽  
Frame Rate ◽  
Memory Unit ◽  
Large Memory ◽  
Image Capturing ◽  
Weak Light ◽  
Very High

The paper presents an ultra-high-speed image sensor for motion pictures of reproducible events emitting very weak light. The sensor is backside-illuminated. Each pixel is equipped with the multiple collection gates (MCG) at the center of the front side. Each collection gate is connected to an in-pixel large memory unit, which can accumulate image signals captured by repetitive imaging. The combination of the backside illumination, image signal accumulation, and slow readout from the in-pixel signal storage after an image capturing operation offers a very high sensitivity. Pipeline signal transfer from the MCG to the in-pixel memory units enables the sensor to achieve a large frame count and a very high frame rate at the same time. A test sensor was fabricated with a pixel count of 32 × 32 pixels. Each pixel is equipped with four collection gates, each connected to a memory unit with 305 elements; thus, with a total frame count of 1220 (305 × 4) frames. The test camera achieved 25 Mfps, while the sensor was designed to operate at 50 Mfps.

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