Monday, 19 March 2012

The heart of Apple's latest tablet


‘Apple, the undisputed leader in enhancing user experience, has always rested on its attempt to define electronic gadgets from being merely application-specific embedded systems to become ornamental possessions. This is true of its latest iteration of its best-selling tablet, the iPad. Although the iPad has already made its mark, the latest release is the first major product launch after the demise of Apple Chief Executive Officer Steve Jobs.

The Retina Display on the new iPad, popularly referred to as the iPad 3, is at the heart of the new tablet. It is the most important of the enhancement, cantered around which the new iPad has been marketed primarily. It boasts the highest screen resolution in any class of mobile electronic gadgets, and Apple is the only player in the tablet segment to bring in this feature. This emphasis on increasing the screen resolution will improve the user experience enormously.

The new iPad sports a couple of fundamental enhancements but is not functionally very different from its recent predecessor. Apple has tried to enhance the user experience by enhancing the fundamentals such as display and connectivity.
Pixelation challenge


We live in the analogue, or the ‘continuous' world, where we can have infinite number of points between any two points in space — infinitesimal granularity. However, a computer or any electronic device performs its functions in the discrete, or the digital world. Computers are constrained in that they can work with only a finite number of points, or finite granularity.

For instance, a photograph on paper has infinitesimal graduations as the eye moves from one region of a picture to another. But on a computer operated digital screen, the graduations happen in steps, although these steps are usually not easily discernible to the human eye. The smallest of the graduations that a computer can render, in an attempt to deceive our senses into perceiving absolute continuity, is called a pixel, or the ‘picture element'.

The smaller the size of the pixel, the more ‘realistic' or ‘continuous' would the pictures appear to our senses. These pixels glow in various colours in a synchronised fashion to project the bright, colourful and realistic images that we see on computer screens.

When the human eye is able to distinguish the graduations or the steps, the display is of poor resolution, as one would have observed on low resolution screens where the edges of images or text appear jagged. The better the screen resolution, the smaller will be the size of the pixels, implying that they will contain more detail. This is at the heart of the push towards higher screen resolution.

Apple, by integrating the ‘Resolutionary' Retina Display on its tablet, has, for sure, heralded the ‘Mega Pixel War' in the tablet segment.
Packing them closer

Housing a mind boggling 3.1 million pixels within a 9.7 inch screen with an LED backlight, the new iPad has introduced a device with the highest resolution in the tablet segment.

In comparison with the high definition screens with a resolution of 1920 x 1080, that are available in the market, the Retina Display in the latest iPad displays a million pixels more on the device, with a resolution of 2048 x 1536. This is not trivial; compared to the iPad 2, the iPad 3 has double the resolution and four times the number of pixels. By quadrupling the pixels, precisely 264 ppi (pixels per inch), engineering challenges such as inter-pixel signal interference, micro-processor overloading and power consumption had to be taken care of.

Each pixel in most of the colour displays, consist of the red, green and blue sub-pixels, emulating the human eye physiology, which consists of the red, green and blue colour-detecting receptors (special neurons) in the retina of the eye.

These sub-pixels glow in various intensities and different combinations additively to render colour displays.
The challenges

With the super dense packing of pixels in the Retina Display, the sub-pixel signals of each pixel would encounter signal interference due to the close proximity of the neighbouring pixels. This concern of inter-pixel interference has been tackled, according to the design engineers at Apple by compartmentalising the pixel area and the current-carrying signal region. This is a marvellous engineering feat — to be able to accomplish this discretion at the micro level of the circuitry, yielding 3.1 million pixels within a 9.7 inch screen.

Ramping up of the number of pixels also means the microprocessor of iPad has more customers — the pixels, on the display to light up and work upon. This has been accomplished by using the A5X microprocessor, a closed architecture, state-of-the-art chip with a quad core graphics drive and a dual core processor. Apple claims, even with this enormous scaling up, the new iPad still yields 10 hours of battery life. All these enhancements, of course, come at the superlative price that Apple is known for.

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