Key technologies of OLED lighting industry

Although OLED lighting products are only in the initial stage, but the current brightness, Oled lighting device efficiency and lifetime in R & D level has reached a high level, such as Kodak (Kodak), the company (UDC), PHILPS (Philips), SIEMENS (Simens), OSRAM (Osram) and Novaled's research have achieved good results. These enterprises in the planning process of OLED lighting industry, in addition to continue to improve the efficiency and life of white OLED, has reduced the price as the main direction of research and development, and even the upper reaches of the material and equipment providers plan included in, to form a complete industrial chain, promoting the development and application of OLED lighting products market.

It is understood, Philips GE, Konica Minolta, Lumiotec, OSRAM and other international companies is expected to 2010-2012 will be launched OLED lighting products, in fact, these companies have started small batch production of OLED lighting products (production companies in the world main road map plan of OLED lighting products such as Figure 1). Nevertheless, OLED lighting to achieve the level of fluorescent lamps and are widely used, there are still many problems to be solved, mainly includes three aspects of efficiency, life and production costs, and the cost should be the key factors restricting the popularity of OLED lighting.

Figure 1 OLED lighting production line

OLED lighting to reach the level of application of fluorescent lamp in efficiency, the power efficiency of at least 70lm/W, although the OLED lighting device about 100lm/W have been reported, but it is produced in very extreme cases, efficiency usually made out of the OLED lighting device is only 30~50lm/W, obviously this not meet the requirements.

OLED high efficiency need to solve the problem of material and structure

OLED lighting to reach the level of application of fluorescent lamp in efficiency, the power efficiency of at least 70lm/W, although the OLED lighting device about 100lm/W have been reported, but it is produced in very extreme cases, efficiency usually made out of the OLED lighting device is only 30~50lm/W, obviously this not meet the requirements.

From the material point of view, to achieve such a high efficiency, must use the phosphorescent material luminescence efficiency is 100%, the green and red phosphorescent materials have no problem to be solved is the blue phosphorescent materials play an important role. Blue phosphorescence efficiency, now is the lack of high stability of luminescent materials, is currently the main technical difficulties hinder the efficiency of the improved OLED lighting device, so the practical development of high efficiency and high stability of blue phosphorescent material production technology has become a main research direction in this field.

From the point of view of device structure, the effective design of device structure is also the key to improve the efficiency of the device. At present, the structure of the device is composed of multiple light-emitting layer, single light-emitting layer, stacked structure and top emitting structure. Multi light emitting layer structure is the preparation of white OLED devices up to a relatively mature technology, the performance of the device, is the best, but a complex process may affect it in the future yield and production cost of OLED lighting device, and the device structure is still sometimes spectrum and chromaticity coordinates with the driving voltage change shortcomings. However, more luminous layer structure due to good device performance, and the spectra and chromaticity coordinates with voltage variation problem could be solved by the design of the device structure, so if you can get it in control and improve the rate of finished products, or the structure is a kind of production technology, the structure is Philips, UDC, Novaled the company currently in use.

Although the single light emitting structure can avoid the changes of color purity with driving voltage in a certain extent, may also simplify the process in the production process, but the efficiency and stability of the unsatisfactory of the structure can not be used in practical applications.

Laminated structure with single emitting layer and multi layer structure of the light emitting characteristics, it is through the charge generation layer of a device structure and a plurality of light emitting units connected in series, laminated device has very good spectral stability, and high luminous efficiency, high brightness and good stability characteristics make fold layer structure device in practical application is very competitive, if you can get further improvement in technology of laminated structure complex, laminated structure of the device is expected to become the mainstream technology of white OLED lighting production.

The top emission structure due to the effective emitting area and improve the efficiency advantages, it may become an important direction of technology development of white OLED lighting, and other structure and top emission structure combine to develop higher performance of white OLED.

Improving light extraction technology under the premise of controlling cost

In addition to the material and device structure, there is a very important technology to improve the efficiency of white light OLED, that is, light extraction technology, which is the OLED lighting devices to achieve power efficiency can be applied when the technology must be used. The extraction technology can be used, in as much as possible to increase the output of light at the same time, must also consider the practicability, so far, researchers have developed many light extraction technology can meet the application requirements, but really is not much, the main reason is the cost problem caused by the complexity of the technology and a large area of.

The present invention relates to a light extraction technology which is relatively good and can be applied, which comprises the following steps: a coupling film composed of a prism or a micro lens is formed on the outer surface of the substrate