report
1.8.6 ICT: Application Profile: Displays

Short application description

There are a wide range of displays applications, the most ubiquitous being displays for portable electronics; such as computers and mobile telephones; and televisions. The current dominant technologies are liquid crystal display (LCD) and plasma display panel. Cathode Ray Tube (CRT) displays are increasingly being phased out in favour of these new technologies.

Graduations of screen sizes range from 1" or 2" to 3.5" for mobile devices, 12"-17" for laptop computers, and 19" to 70" for televisions. Typically all devices would be full colour, and with the exception of older screens for mobile devices, would be capable of showing full motion video.

There are three main groups of nanotechnology-enabled display technologies that are relevant for this application:

• Organic Light Emitting Diode (OLED), in which the emissive layer is an organic compound
• Field Emission Display (FED), in which an element such as a carbon nanotube acts as an electron source, striking a coloured phosphor
• Surface-conductive Electron-emissive Display (SED), which is similar to FED in many ways, the difference being that it only employs a single field emitting element - which could also be a CNT - per pixel.

The technology behind each of these approaches is described in more detail in the Technology Analysis section.

Functional requirements

The function requirements of displays include:

Refresh rate

A measure of how often the display refreshes the image that it is displaying - in CRT displays, this was the length of time taken for the cathode ray tube to scan across each pixel. A display with a slow refresh rate may appear to flicker. The refresh rate (or response rate) for LCDs is determined by the amount of time it takes to instruct each liquid crystal to change its state. A commonly used refresh rate is 60Hz, but higher rates (which are a multiple of 24, the number of frames per second in video film) will reduce the sensation of ‘judder' or motion blur.

Viewing Angle

LCD displays can be difficult to view at oblique angles - an effect which can easily be seen on a laptop computer screen. The viewing angle determines a ‘cone of visibility' extending from the display, within there is sufficient contrast for a person to view the image being displayed. A narrow viewing angle restricts some applications for televisions and displays.

Power

The power consumption of a display is particularly important in battery-powered mobile devices; within with they can be a major source of power consumption. LCDs have typically been considered to have higher power requirements than alternative display technologies, due to the requirement that they be backlit (and with part of this light then being blocked by a polarising filter).

Contrast Ratio

The contrast ratio of a device describes the ratio between the light intensity of the lightest part and the darkest part of the display. Taken in isolation, a higher contrast ratio should give a better display performance. Improvements to contrast ratios have been one of the selling points of OLED displays, which claim contrast ratios of 1 000 000:1 (LCD displays would typically have a contrast ratio of 5 or 10 000: 1). The noticeable effect for a viewer is that the black areas of an OLED display appear to be true black, whereas in an LCD they would be very dark grey.

Lifetime

A display's lifetime is often expressed as the time it will take for a display to lose half of its brightness, and is measured in hours. 60 000 hours is considered typical for LCD and Plasma displays. OLEDs have had particular challenges in longevity, as organic materials used have a tendency to degrade - this is a priority area in OLED research.

Boundary conditions

There are a set of very basic boundary conditions which apply in the market for device displays and television; that the device is capable of showing moving, colour images - whilst the major technologies described here do this, flexible displays are restricted to images which change far more slowing than 24 frames per second. 

Product examples

Sony XLE 1

Sony's XLE 1 is an OLED digital TV[1], and is currently commercially available. The screen size is 11" - OLED laptop displays of similar dimensions are also commercially available, though larger sizes that would be more suitable for televisions are not, as yet.

The XLE 1 is sold on its image quality and thinness (it is 3mm wide), through the product itself is relatively expensive at US$ 2499 - several times more expensive than much larger LCD and Plasma displays.

Nanospindt FED (Sony / FE Technologies)

A 19" FED was demonstrated at a number of events in 2008, showing an input from a high definition source (a Playstation 3). Coverage of the display cited a distinct lack of motion blur and true black, making for an impressive visual performance.

Toshiba SED

Toshiba first demonstrated an SED display in 2006, and it was then announced that commercial SED products would ship in the latter half of 2007. These were to have been targeted for profession users such as TV studios - an application in which the demand for high quality colour reproduction renders the users less price sensitive[2].

However, the technology was then the subject of a lengthy legal wrangle between Toshiba, Canon, and Applied Nanotech Inc. Canon and Toshiba had formed a joint venture named SED Inc. Applied Nanotech subsequently sued Canon, alleging that they had violated a confidentiality agreement by sharing information with Toshiba. SED Inc. then became a wholly owned subsidiary of Canon in 2007[3].  Applied Nanotech ultimately dropped their lawsuit in December 2008, enabling Canon to resume production of SED displays. Uncertainty remains as to the amount of development Canon was able to carry out during this period, and how close to market this technology now is.

Motorola Nano Emissive Display (NED)

Motorola demonstrated a 5" prototype NED in May 2005 with full colour video and a thickness of 3.3mm. The NED is believed to be Motorola's term for what is more generally understood to be a FED. Since this release, no more information has been forthcoming about Motorola's development of this technology.

Economic Information and Analysis

FED/NED and SED displays are not currently commercially available. Assuming that Canon resumes work on their SED; this is likely to be first to market in 2009/10.

OLED displays are commercially available, albeit largely restricted to portable electronic applications such as mobile phone screens and laptops. iSuppli states that the current OLED market size is around US$ 500, with over 80 000 units shipped in 2008[4]. Analysts Display Search predict that OLED displays will account for 5% of the display market by 2015 (the proportion currently being around 1%)[5].

Selected Key Companies Profiles

Canon

As of 2007, Canon wholly owns the assets of SED Inc., a joint venture established by Canon and Toshiba to develop Surface-conduction Electron-emitter Displays. Canon does not currently sell televisions or displays, but they are incorporated into the company's products, including camcorders and digital cameras.  

Sharp

Sharp is a Japanese electronics manufacturer with 2008 sales of US$ 35.5 million. [6] Audio-visual equipment - including LCD colour televisions - accounts for 39.4% of total sales. LCD modules for other devices, such as mobile phones and computers, are a further 30.5% of Sharp's annual sales. The company's research work includes further improvements to LCD technology, and the inclusion of optical sensors to record user input (as an alternative to touch screens).

FE Technologies

FE Technologies (http://www.fe-tech.co.jp/en/index.html) is developing FED technology under the product name ‘nano-Spindt'. The company is a spin-out from Sony, and continues the research and development that was carried out by that company. 

Motorola

Motorola released a 5" NED prototype in 2005. At this point the company claimed to have over 150 patents "in CNT and flat panel displays". No information about the company's NED has been available since this point.

[1] http://www.sonystyle.com/webapp/wcs/stores/servlet/ProductDisplay?catalogId=10551&storeId=10151&productId=8198552921665327724

[2] http://techon.nikkeibp.co.jp/english/NEWS_EN/20061225/125850/

[3] http://www.canon.com/press/2007/sed2007jan12.html

[4] http://www.isuppli.com/Abstract/ABSTRACT%20-%20OLED%20Market%20Tracker%202008.pdf

[5] http://www.displaysearch.com/cps/rde/xchg/displaysearch/hs.xsl/090219_oled_display_revenues_expected_to_reach_6b_in_2015.asp

[6] http://sharp-world.com/corporate/ir/library/annual/index.html