Smartphone Displays - AMOLED vs LCD

Introduction

Very often your only connection with the world is your phone's display. With the advent of smartphones, their screens are becoming windows to the information world, as you want to see it. Google's Eric Schmidt called it the other day the era when you will never be alone, or bored. Some people don't really care what screen they are looking at – they want to quickly check time, call, read messages and answer to email, without worrying too much about tidbits like resolution and color saturation. Others spend hours browsing rich websites, watching YouTube videos, or reading e-books on their smartphone screens.

That second category will only be growing, as it is hard to resist all the multimedia noise easily accessible from your phone. Moreover, in developing nations, the whole desktop PC/cable internet era might be skipped altogether for some regions, and people's first Internet access there could very well be via a smartphone tied up to a data plan. That is the reasoning behind the big battles among Google, Microsoft, Apple, Nokia and others, big and small, these days. And that is why screen technologies are becoming a major selling point -it is amazing what achievements have been reached in the span of just a few years, in terms of brightness, clarity and durability of today's touchscreens.

Technologies Overview

The two existing mainstream technologies for smartphone displays are LCD and OLED. Their advanced iterations in those gizmos are IPS-LCD, as found in Apple’s iPhone 4, and Super AMOLED, as present in the Samsung Galaxy S. Therefore, after a brief overview of the technology behind them, we will compare the two flagship smartphones displaywise, try to pierce through the marketing fluff, and come up with a conclusion, more suited for real-life decision making. Bear in mind that these two technologies are future-proof, and will be utilized in smartphones for the next few years as well.

Liquid Crystal Display (LCD), has been around for a while. We won’t go as far back as 1888, when an Austrian botanist discovers liquid crystals, but rather mark 1972 and 1973 when the first LCD watch and calculator were introduced. Then rapid advancements followed, adding colors, and improving the viewing angles, brightness and efficiency of the then power-hungry technology, which requires backlighting. Most major display companies make LCDs, the technology is very mature, without much production and supply issues.

Organic Light-Emitting Diodes (OLED) is a much newer development than LCD. Luminescence of organic materials when electric current is applied to them, was first observed in the 1950s by French researchers. Cambridge scientists reached the stage of efficient light emission from a green organic polymer in 1990, and the first commercial OLED devices came in the early 2000s, three decades after LCD ones. Below is a funny setup to explain the process of organic light emission, demonstrated on a pickle by Vladimir Bulovic from MIT:



A lot of the companies that were producing OLED screens, such as Sony, or Toshiba, have currently shelved their R&D and production plans due to cost-cutting. Thus Samsung is becoming the OLED industry juggernaut. The Koreans hold 98% of the world’s Active Matrix OLED (AMOLED) market in 2010.

On paper, and in the research labs, OLED has all the advantages to get you excited, when compared to LCD:

Simpler construction – the thin layer of organic polymers emits light itself, when electric current is applied, so no additional backlighting is needed. On top of that, production methods can incorporate all the elements needed close to one another, and OLEDs can even be printed on an industrial printer, if some of the ongoing research makes it up to commercial scale. Thus OLED displays can be extremely thin, even bendable. Illustrated below are the elements, constructing a typical LCD, and a typical AMOLED screen:



Low power consumption – due to the lack of powered backlighting, OLEDs are supposed to be more energy efficient than regular LCDs;

Brightness – since it is light-emitting, OLED is potentially the brighter technology. The very high contrast ratios also contribute to the brighter impression;

Higher contrast ratio – black color from OLED screens is indeed black, due to the simple fact that the pixel is off at that time, whereas the LCD backlighting is still on, producing greyish black. The contrast ratio of AMOLED displays is extremely high;

High and stable color gamut – the emissive displays have much wider color gamut reproduction, and this cannot be easily improved in LCD;

Faster response times – the organic diodes fire up and emit light immediately when current is applied, whereas with LCDs, some motion blur might be present with fast moving objects;

Wider viewing angles – LCD suffers from picture deterioration when viewed from certain angles, due to the nature of the direction in which light travels through the liquid crystals, while OLED screens’ brightness and color gamut are left intact up to almost 180 degrees of viewing;

Wider operational temperatures – your eyes will keep chugging photons from your OLED screen long after its LCD brethren has frozen or overheated.

"Then why isn’t everybody using AMOLED screens in their gadgets?", we could ask.