Organic light-emitting diodes hold promise for powering our future generations of electronic displays, lighting, and signage. They blend high brightness and contrast with low energy consumption, while parallel research in new materials could bode well for thinner and flexible OLED installations in unique and once-thought impossible ways.
Organic light-emitting diodes (OLEDs) are the future of lighting and displays. OLEDs can be defined as solid-state semiconductor devices that are made from thin films of organic molecules that create light when electrical power is applied to them. These devices are 200 times thinner than a strand of human hair. Advances in OLED technology may lead to a new age of low-energy display and lighting products that are larger, transparent, and flexible.
OLEDs emit soft light evenly across large areas. OLEDs offer crisp and bright displays on electronic devices and use less power than conventional light-emitting diodes (LEDs) or liquid crystal displays (LCDs) that are commonly used today. Any device that uses conventional types of LEDs and LCDs can benefit from OLED.
Efficient form, intense brightness, and lower power consumption make it possible for OLEDs to be incorporated into just about any design. OLEDs are in commercial use already, for screens on TVs and smartphones and for residential lighting. In addition, the performance of white-light-emitting OLEDs has shown steady improvement, and they are considered by many to be the light source of the next generation. Since global energy prices are rising again and are likely to continue to rise as the Indian and Chinese economies grow, the drive to achieve viable and cost-effective OLED products may become more focused.
One of the key features of an OLED display is that it works without a backlight. Therefore, this type of display features deep black levels and a higher contrast ratio than a LCD in low ambient light conditions, such as a dark room. Also, OLEDs refresh almost 1,000 times faster than LCDs; therefore, a device with an OLED display could change information in almost real time. There are several types of OLED technologies (for example, passive-matrix OLED), and all of them have particular applications.
One area where this technology is finding applications is large panel displays. OLED tiles can be fitted together seamlessly, making just about any size or shape of display possible — including curved ones. Thinner and lighter displays compared with LED screens will enable them to be installed in places previously thought impossible. Their light output is significantly higher than LCD displays, making OLEDs suitable for high-ambient light areas such as airport and train terminals as well as shopping malls. Their performance matches top-quality high-resolution LED screens while being significantly easier to install.
Today rigid glass substrates are used to produce OLEDs, but the research into the use of thin glass, metal foil, and plastic substrates may put OLEDs squarely into the commercial realm. Utilizing the flexibility of OLEDs enables manufacturers to integrate these materials with roll-to-roll manufacturing processes that use less costly, solution-processed emissive materials that allow for the production of flexible displays and lighting products.
The other obvious application for OLEDs is lighting. Although LEDs are the predominant technology, OLEDs will become more applicable as their costs to manufacture come down. This form of illumination does not heat up even after numerous hours of use; it does not contain damaging substances like mercury and consumes little power.
OLED lighting can be produced with a thickness of only 2 mm. The change will not be in the installation process but instead in using lighting in new and unique ways. Materials may become even thinner in the future and therefore be able to curve more freely, making it possible to apply them anywhere and in any way.
Developing adequately durable and flexible OLEDs will necessitate the need for better materials and further research of manufacturing tools and processes. Flexible plastic substrates require more effective barrier layers to protect OLEDs from the effects of moisture and oxygen. Thin-film encapsulation is also required to create thin and flexible metal- and glass-based OLEDs.
A number of companies (GE, Samsung, Mitsubishi, Philips, and many display manufacturers) and research institutes are studying the use of metal and plastic substrates suitable for OLED applications. This may eventually result in very flexible OLED panels for both lighting and display products, ensuring that any type of surface area, flat or curved, will be able to host a light source.
A number of innovative demonstrations by lighting companies have already hinted at the potential of flexible OLED technology. Considerable research efforts are being invested, and, if successful, flexible OLED panels may become commercially available as soon as at the end of this decade.
Troy David is president of Keystone Electronics Corp., a manufacturer of electronic interconnect components based in Astoria, N.Y. Keystone’s products include battery holders and clips, brackets, fuse clips and holders, screw terminals and terminal blocks, terminal boards, and spacers. Its capabilities include stamping, machining, and assembly services, as well as application engineering assistance for product modifications. The company is RoHS compliant and ISO 9001 certified.