Key Technologies and Research Development of CMOS Image Sensors _SEMINAR PPT

8/2/2019 Key Technologies and Research Development of CMOS Image Sensors _SEMINAR PPT

http://slidepdf.com/reader/full/key-technologies-and-research-development-of-cmos-image-sensors-seminar-ppt 1/19

Key Technologies and Research

Development of CMOS Image

Sensors



INTRODUCTION

There are two types solid-state image sensor:

• CCD (Charge Coupled Device) SENSOR:A CCD Image sensor is ananalog device . When light strikes the chip it is held as a smallelectrical charge in each photo sensor . The charges are converted

to voltage one pixel at a time as they are read from the chip .Additional circuitry converts the voltage into digital form.

• CMOS(Complementary Metal Oxide Semiconductor) SENSOR :InCMOS sensor, each pixel has its own charge- to-voltage conversion ,

and the sensor often includes amplifiers , noise-correction , anddigitization circuits . These other functions on-chip increase thedesign complexity but reduce the space required for processing.



CMOS IMAGE SENSOR(CIS)

The development of CMOS image sensor has experienced two

generations:

1.PPS (Passive pixel sensor) : These where the first image sensor devices

used in the 1960s.In passive pixel CMOS sensors , a photosite converts

photons into an electrical charge . This charge is then carried off the

sensor and amplified . The problem with these sensors is noise thatappears as a background pattern in the image . To cancel out this noise ,

sensors often use additional processing steps.

2.APS (Active Pixel Sensor):Image sensor elements with in-pixel

amplifiers are called ‘APS’ . Circuitry at each level determines what its

noise level is and cancels it out , thus reducing the noise associated with

each pixel .It is this active circuitry that gives the active pixel device its

name.



ADVANTAGES OF CIS

• Wide dynamic range

• pixel size

•

read out speed• power consumption

• anti-radiation capability



TWO KEY PROBLEMS OF AFFECTING IMAGE

QUALITY OF CMOS SENSOR

• Structure of CMOS Sensor

• Noise of CMOS Sensor



Structure of CMOS Sensor



Noise of CMOS Sensor



LATEST RESEARCH PROGRESS OF

CMOS IMAGE SENSOR

•

New Sensor-Exmor R CMOS

• Development of Noise Suppression for CMOS

Image Sensor



New Sensor-Exmor R CMOS

Exmor is the new technologyimplemented by Sony in the

field of CMOS Image sensors .

This revolutionary new

technology performs on-chip

analog to digital conversion

and two-step noise reductionin parallel on each column of

CMOS sensor . The new

Exmor R CMOS sensor work

on “BACK ILLUMINATED

TECHNOLOGY” unlike

conventional sensors that

works on “FRONT

ILLUMINATED TECHNOLOGY”.



Working of Exmor R CMOS sensor• In conventional sensors , the light receptors are placed behind the

wire circuits.(Front I Illuminated Technology).The wire circuits partlyblocks the light , while travelling to the receptive areas of sensor ,thus reducing the total amounts of light that reach to the lightreceptor.

•During low light conditions , the signals from the sensor have to beboosted electronically , creating the noise that’s seen as fuzzyimages or grains.

• The Exmor R CMOS sensor that works on back illuminatedtechnology which replaces the position of layers , so that lightreceptors are not blocked by wire circuits . Thus the light falls to

receptive areas of the of sensor and thus resulting in more light andthere is no need to boost the signals from sensor . This , in turnreduces the noise up to a great extent and hence results inimproved video and still picture quality with less light especially inlow light conditions.





Development of Noise Suppression

for CMOS Image Sensor



THE APPLICATION OF CMOS IMAGE SENSOR IN

THE FIELD OF REMOTE SENSING

• The Observation Application of UV Spectral

•The Observation Application of Bright Stars

• The Application of Remote Imaging

• The Application of Star Tracker

• The Application of Solar Sensor



The Observation Application of UVSpectral

• CMOS image sensor uses standard production technique of CMOS semiconductor, the noise margin is big, anti-jamming

ability is very strong, spatial radiation protection ability is very

good, therefore CMOS image sensor can be used in the UV

spectral detector.



The Observation Application of Bright

Stars

• When we use CCD imaging system to detect the bright star,

the pixel element is very easy saturated, this brings a series of

problem, such as blooming and smear and so on. If uses the

CMOS imaging system, which dynamic range is big, and it

does not have overflow between the pixel element, so wemay use CMOS imaging system to observe starry sky, which

includes the bright stars. Similarly, in other needs of the large

dynamic range of space applications, we also use the CMOS

imaging system.



The Application of Remote Imaging

• At present, there are many earth observation imagingsystems, but the price of imaging system is very expensive,the power consumption is very high, the system size is veryhuge, it is difficult to achieve miniaturization. With thedecrease of spacecraft size, the light imaging technology will

become the main observation method, but the CCD imagesystem is difficulty to meet the requirements of volume,weight and the power consumption, however, the CMOSimage sensor has some advantages in power consumption,volume, weight, the cost, the radio resistance ability and so

on, therefore the CMOS image sensor has a widespreadapplication prospect in the field of remote imaging.



The Application of Star Tracker

• With the development of spacecraft and the satellite technology, thestar tracker plays a vital role in navigation systems of spacecraft. Thestar tracker is mainly used for high accuracy posture determining of thesatellite, the airship, the aerospace craft, space station, it can be usedin rockets, missiles, guidance and control, but also can be use forprecise location and survey of the submarine, ships. Tradition star

tracker is based on CCD image sensor, because higher weight, powerconsumption and volume, the CCD image system is difficult to use inmicro-satellites.

• If we use the CMOS image sensor, these problems can be solved verywell, therefore under the premise of guaranteeing the image quality,CMOS image sensor can be used in star tracker.

•



The Application of Solar Sensor

• The solar sensor is a widely used posture sensor, which has

strict requirements to the system weight, the system volume,

the system power consumption and so on, at the same time,

the rapid localization needs a fast readout speed. In view of

the technical advantages of CMOS sensor, it is impossible touse CMOS image sensor to replace CCD in solar sensor.



THE END

THANK YOU

*NO QUESTIONS PLEASE

*DUE TO LACK OF KNOWLEDGE IN VLSI

Key Technologies and Research Development of CMOS Image Sensors _SEMINAR PPT

Documents