SMART PIXEL ARRAYS

Introduction Crux of a smart pixel array Components of SPA Packaging of smart pixel arrays Applications, Advantages & Disadvantages Conclusion Future scope

CONTENTS:

UNDERSTANDING A PIXEL :-It is the smallest unit of picture that can be represented or controlled. Each pixel has its own address.

The Address of a PIXEL corresponds to its co ordinates.

What is a SMART PIXEL??

Smart Pixels are the integration of photo detector arrays and processing electronics on a single semiconductor chip .

These are driven by their capability to perform parallel processing of large pixelated images by reducing a complex image into a manageable stream of signals.

SMART + PIXEL = “SMART PIXEL”

The name SMART PIXEL is a combination of two ideas

"PIXEL" is an image processing term denoting the smallest part of an image and

"SMART" is coined from standard electronics and reflects the presence of logic circuits.

FINALLY, a smart-pixel array can be defined as a two-dimensional array of optoelectronic devices that combines optical inputs and outputs with electronic processing circuitry.

SITUATION BEFORE THE ADVENT OF SMART PIXEL ARRAYS (SPAs):

In order to perform logical functions it requires a certain amount of interaction for processing which took significantly more optical energy .

This disadvantage forced the inventors to process the logical functions electronically giving birth to the SMART PIXEL ARRAYS.

WHY SMART PIXEL ARRAYS ??

Smart pixel arrays (SPAs) hold great promise as an enabling technology for board-to-board interconnections in digital systems

For taking advantage of the high space–bandwidth product of optics, optically interconnected two dimensional arrays of smart pixels have emerged as an attractive interconnection platform

SPAs as an emerging optoelectronic technology is crucial to meet the demanding performance needs in high-speed switching ; optical interconnects in computers, and flat-panel display applications

CRUX OF SMART PIXEL ARRAYS

“Process electronically, communicate optically.”

VERTICAL CAVITY SURFACE EMITTING LASER (VCSEL)

The Vertical Cavity Surface Emitting Laser (VCSEL) is a very important and useful light source.

They are constructed out of material that is convenient for fabrication of photo detectors and in some cases logic.

COMPONENTS OF SPA :

OPTICAL DECODER

PROCESSING ELEMENTS

I/O PINS

VCSEL DRIVERS

PHOTO DETECTOR ARRAY

PACKAGING :

Thermosonic flip-chip bonding is used to mount both the VCSEL chip and the CMOS chip to the glass substrate.

Then they are mounted in ceramic packages which have holes drilled in their bottoms in order to provide optical access.

The package is then closed by adding the heat-sink/ground-plate.

APPLICATIONS OF SPAs

SPAs have an umpteen No. of uses in the field of image processing, data processing, digital signal processing.

Many applications requiring high performance image capturing use smart-pixel arrays, which integrate very special functionality at the pixel level.

The 3D image sensors consisting of smart pixel arrays are used to evaluate size, shape and volume in industrial automation applications.

Smart pixel arrays are also used for optical data interconnect and optical memory access. 

Microscopic topographer

Megapixel high speed camera

3D camera3D Image Sensor

ADVANTAGES OF SPAs :

Smart pixel arrays provide high data-transmission rates through high-speed switching.

Smart pixel arrays provide decreased cross-talk, by virtually eliminating interference phenomenon.

Smart pixel interconnects are lighter as they are made of feather-light fiber ribbons when compared to today’s copper wires. 

Smart pixel arrays provide high processing speeds by consuming significantly less optical power.

DISADVANTAGES OF SPAs

The greatest challenge being faced by smart-pixel technology is economic.

There exists Potential problems’ in getting the electrical design to interact with the optics

The low efficiency of photodetectors results in reduced switching speed thus decreasing the data transfer rate.

Non-uniformity may result due to fabrication imperfections.

CONCLUSION:

Thus Smart pixel arrays , the integration of photodetector arrays and processing electronics on a single semiconductor chip, have been driven by its capability to perform parallel processing of large pixelated images and in real-time reduce a complex image into a manageable stream of signals that can be brought off-chip. Data retrieval rates will also improve by orders of magnitude by using smart pixel arrays.

THE FUTURE

The major goal will be to achieve more compact packaging and to scale the SPAs to larger array dimensions. The former not only leads to smaller components, but shortens electrical connections within the SPA, thereby leading to higher potential speeds.

The SPAs have a great prospect in the future especially in the field of image processing.

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