Easternkodak is a leading manufacturer in the small molecule OLED camp. It has mastered most of the core technologies of OLED materials and device design, and has more than 300 patents. So far, nearly 20 companies have been authorized by easternkodak. Geographically, easternkodak’s patent licensing objects began to focus on Japanese manufacturers. Then easternkodak gradually shifted its licensing scope to manufacturers in Taiwan and Hong Kong, including rheniubao, Dongyuan laser, Guanglei, lianzong Optoelectronics in Taiwan, truly international and Jingdian international in Hong Kong.
Easternkodak does not focus on European and American manufacturers. In 2001, easternkodak authorized its patent to European manufacturers (opsys Ltd.) for the first time, and there are few American companies licensed by easternkodak. Most of these Asian manufacturers who have obtained OLED patents from Eastern Kodak have LCD industry background, such as Sanyo and Samsung, so they have considerable advantages in product development and market channels. Eastern Kodak chose these manufacturers as patent licensing objects, which well promoted the commercialization of small molecule OLED technology.
Small molecule OLED devices can be manufactured by vacuum evaporation technology. Compared with devices based on p-led technology, sm-oled not only has lower manufacturing process cost, can provide display capacity of all 262000 colors, but also has a long service life. At present, the technology and process of small molecule OLED are more mature than that of polymer OLED, and has entered the market stage. The commercialized OLED displays can be divided into sm-oled with phosphor and passive matrix substrate, polymer + passive matrix substrate, and small OLED displays composed of active sm-oled. The vast majority of small and medium-sized OLED display products in the market are sm-oled, which are mainly used in MP3, mobile phone, on-board equipment and instruments.
Generally speaking, the brightness of small molecular materials is inversely proportional to their lifetime, so finding a balance between the two becomes the only solution. At present, the company has developed blue light materials with brightness of 200 CD / m2 and service life of more than 10000 h and green light materials with brightness of 200 CD / m2 and service life of more than 50000 H. In addition, Toyo ink’s green, blue and orange materials have also reached the practical stage. The biggest problem at this stage is red luminescent materials.
At present, the red light materials of Japanese manufacturers are acceptable if only their color purity is considered, but they have not reached the point of practicality if both service life and luminous efficiency are to be considered. In contrast, UDC has developed red and green materials with certain quality in color purity and service life. The company’s red light materials reach x0.71, Y: 0.29, service life of more than 10000 h and luminous efficiency of 6% on the chromaticity diagram. The green light is X: 0.28, Y: 0.64, service life of 10000h and luminous efficiency of 10%.
Although Kodak has not announced the luminous efficiency, the service life of red and green luminous materials has reached 4000H, and the chromaticity diagrams have reached x0.628, y0.368, x0.289 and y0.65 respectively. However, the above two manufacturers have not achieved much in terms of Blu ray materials. Therefore, at this stage, no material manufacturer can provide RGB three primary color luminescent materials that meet the three elements of color purity, service life and luminous efficiency at the same time.
Although the small molecule OLED has a multilayer structure, the process is also quite simple. The specific process is as follows: first, evaporate a layer of transparent ITO anode on the glass or transparent plastic substrate, cover it with a passivation layer, and place p-type and n-type organic semiconductor materials (i.e. hole and electron transport layers) on the passivation layer, The contact surface of p-type and n-type organic semiconductor materials is the organic light-emitting layer, then evaporate magnesium silver alloy on the top to form the cathode, and finally bond the anode and cathode lead. The internal coating of OLED is very thin, only 100 ~ 150nm, and the thickness of LED chip is at least μ M pole.
Editor in charge: Tzh