Next-Gen Displays Enabling Super-Friendly Devices (Part 1)

Interactivity is emerging as a key differentiating factor in the display world, and so are other aspects such as greenness, flexibility, performance, energy consumption and heat dissipation. Sitting in the background, powerful chips and software code are working magic to achieve these and other targets.

With pinches and tickles, new touch-enabled display technologies are making devices more personal than ever before

The most conspicuously visible aspect that ex­cites most customers about today's electron­ics products is the dis­play. Be it a new cell phone, tablet, television or laptop, the first thing that people look at is how bright and clear the display is. Understand­ably, the displays are fast evolving. Even as older screens are giving way to high-definition (HD) ones, quad HD and ultra HD are already on their way. Whether you are a fan of liquid-crystal displays (LCDs), light-emitting diode (LED) displays or Plasma screens, there is some im­provement happening every day in their performance or clarity.

A sample of Plasma screen

That said, the current genera­tion of mobile users has triggered a fresh set of parameters for evaluat­ing displays, and a brand new set of challenges for display makers and researchers. Interactivity has emerged as a key requirement, giv­ing rise to improved touch screens and immersive technologies. The need to conserve battery life has made engineers focus their energy on reducing the power consumed by displays.

As devices are getting packed into smaller footprints, there is also a need to make cooler displays that do not affect the performance of surrounding components. People spending a lot of time outdoors love to watch movies or play games on their mobile gadgets in their free time. This is enforcing the need for higher display performance even in smaller screens.

Likewise, the need to use mobile phones in rugged outdoor environ­ments is pushing manufacturers to come up with displays that show clear images even in bright daylight, robust and flexible displays that are not damaged by a fall, and so on. On top of this, there is the much-hyped 3D trend!

It takes a multi-disciplinary ap­proach to solve these problems and create a perfect experience for the us­ers. Materials sciences, nanotechnol­ogy, chemical engineering, physics, electronics, integrated circuit (IC) de­sign and software development are all waltzing together to create the super displays we see today. Much of the magic is, in fact, done by the powerful little chips and code that work in the background. Here is a quick round-up of some interesting display-related de­velopments in the year gone by.

Lighter and brighter touch screens - Apple style

Since people spend a lot of time using technology, they like their devices to be more interactive, with more natural forms of engagement. Some like to give voice inputs, while others like gestures. This demand for interactivity is greatly influencing the touch features of displays.

Apple-style touch-screen device

It is not surprising then that Apple adopted in-cell touch sensing in iPhone 5 despite knowing that it would raise the cost of the phone significantly. A normal capacitive touch screen uses a layer of glass on top and a layer of indium tin-oxide (ITO) underneath it. ITO is transparent and electrically-conductive. When a finger is brought near it, it acts like a capacitor - the capacitive change is detected by the circuitry in the phone, and the finger's position tracked. Below the ITO layer is another layer of glass, which has a second layer of ITO on it to isolate the LCD screen from electrical noise. So, actually the image has to go through two layers of glass and ITO. Even if you assume the best-quality glass and minimal refraction, some amount of clarity is lost. Plus, having multiple layers also increases the weight.

It is not surprising then that Apple adopted in-cell touch sensing in iPhone 5 despite knowing that it would raise the cost of the phone significantly.

In-cell multi-touch technology tries to overcome these problems by combining the LCD and touch sensing layers. It integrates touch into the thin-film transistor (TFT) LCD manufacturing process, obviating the need for additional sensors and glass.

Apple appears to have been thinking about this since as early as 2006, when it filed a provisional patent for methods of including touch ca­pabilities in displays. In August this year, they were granted a patent for an exten­sive application that covered several ideas as well as manufac­turing processes that could be used to build the displays. The abstract mentions that there are several forms in which the touch sensing elements may be integrated with the display circuitry: "Touch sensing elements can be completely implemented within the LCD stack up but outside and not between the color filter plate and the array plate. Alternatively, some touch sensing elements can be between the color filter and array plates with other touch sensing elements not between the plates."

Japan Display recently showcased three prototype displays in collabora­tion with Sony, Toshiba and Hitachi. Hyped as 'Innovation Vehicles,' these displays represent the technologies that will be incorporated into products in the recent future. One of the innova­tive features of these prototypes is the Pixel Eyes technology, which is compa­rable to in-cell sensing.

According to the company's an­nouncement at FPD International 2012, "In Pixel Eyes technology, the touch-panel is built in, rather than being attached from outside. The structure becomes simple, so it's easy to make the display thin. Such a thin display is very sensitive, so we've utilized that to enable writing with a pen. Currently, finger operation is the norm, but we would like to provide a pen-drawing solution next."

A screen that can bulge into buttons

We like to swipe and pinch our screens, but there are still times when we wish for a traditional keyboard experience - say, when typing a long document.

Californian company Tactus Tech­nology together with Touch Revolution seems to have an answer. Their new touch panel looks like the normal touch screen displays on existing handheld gadgets but it uses a tactile layer that sits atop the touch screen. This tactile layer is composed of fluid-filled micro­-channels, which can alter fluid pressure and redirect the liquid to create blister-­like buttons. Similarly, it can also make the buttons disappear in a jiffy.

This morphing technology can be used to give users a keyboard on-demand experience, by transform­ing a touch screen's flat surface into real physical buttons. While in the initial stages the company has pre­programmed the size and shape of the buttons, in the future it will be possible for the user to configure these too. The tactile layer consumes very little power while forming the buttons, but there is no power consumption once the but­tons are active.

This technology is expected to be used in products starting 2013.