8/14/2019 New Amorphous Silicon Image Sensor for X-ray

1/21

SEMINAR ON

NEW AMORPHOUS SILICON IMAGE

SENSOR FOR X-RAY DIAGNOSTIC

MEDICAL IMAGING AND OTHER

APPLICATIONS

PRESENTED BY: CHAITHRA MANDANNA K.

4KV05EC017

1

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

2/21

Contents Introduction

What Is a-Si?

Working of sensor and Block Diagram

Fabrication

X-Ray Detector System

TFT/Photodiode array

Imaging Examples.

Advantages.

Applications

Conclusion

References

2

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

3/21

Introduction

New high-resolution amorphous Silicon (a-Si)

image sensors specifically configured for

demonstrating film-quality medical x-ray imaging

capabilities.

Here we use dpix Amorphous silicon x-ray

image sensor array technology.

3

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

4/21

What Is a-Si??

Amorphous silicon (a-Si) is the non-crystalline

allotropic form of silicon. a-Si can be deposited at

75 degree Celsius temperature.

a-Si has become the material of choice for the

active layer in thin-film transistors (TFTs),

which are most widely used in large-area

electronics applications.

4

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

5/21

5

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

6/21

Fabrication Process

a-Si array is patterned on a large glass substrate.

Deposition and patterning of various metal layers,

thin film dielectrics ofSilicon nitride and a-Si to

form the TFT.

Depositions ofa-Si in the sequence nip to form the

photodiode.

Dielectrics for interlayer isolation and passivation. Gate driver and charge amplifier ICs are connected

to each line on the glass using TAB.

6

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

7/21

Photo micrograph of a 127 micron pixel

sensor.

7

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

8/21

X-Ray Detector SystemA 30 x 40 cm active area 127 micron pixel

image sensor module with gate and data boards TAB

(Tape-Automated Bonded) to the glass, which is

mounted on an aluminum backing plate.

8

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

9/21

Anatomy of a Pixel

9

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

10/21

Inside the dpiX a-Si Active Matrix Layer

10

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

11/21

What are Scintillators ???

Scintillators exhibits the property of emitting

optical photons in response to ionizing radiation.

Scintillators work by converting x-rays to visible

light.

Scintillator material used here is x-ray sensitive

phosphor - cesium iodide (CsI).

11

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

12/21

TFT/Photodiode array

Gate lines 3,200

Data lines 2,304

Total pixels73,72,800

Dimension30*40 cm

12

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

13/21

Advantage over conventional X-ray

technology Images can be displayed almost immediately on a

computer screen.

Can be improved through software.

Enabling quick and effective diagnosis.

Images can be shared electronically with radiologists

who are not on site.

Images can be stored electronically. Patients are benefited by a reduction of the x-ray

dose required to capture an image.

13

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

14/21

A digital x-ray image of A digital x-ray image of

a human hand phantom. a human chest phantom.

14

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

15/21

A digital x-ray of a bullet fired into

a light bulb, taken with a fast x-ray pulse.

15

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

16/21

Applications

A) Medical X-Ray Imaging

Radiographic Imaging

Cardiology

Dental Imaging

B) Other Radiation Imaging Applications

Non-Destructive Evaluation (aircraft

inspection , electronic inspection etc..)

C) Security

16

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

17/21

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

18/21

Future Developments

Array Size

Sensitivityimprovements are expected with

higher sensitivity phosphors. (scintillating

material)

Fill-factorthe fraction of light sensitive area in

each pixel.

Applications

18

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

19/21

Conclusion

New a-Si x-ray image sensor is well suited to

medical imaging and other applications.

a-Si technology provides fast, convenient and

mobile ways to take real-time images. The ability

to get immediate x-ray images for detection,

review, analysis, remote evaluation and decision

makes this is an invaluable tool for hundreds ofindustrial applications.

19

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

20/21

References

[1] IEEE transactions on measurements, volume41,issue 7, august 2008.

[2] Paper on Amorphous silicon TFT X-Ray Image

sensors by Richard L. Weisfield.

[3]www.dpixbrochure.com

20

8/14/2019 New Amorphous Silicon Image Sensor for X-ray

21/21

THANK YOU

QUERIES .

21