标签：OLED technology

Working principles of OLED technology

Organic Light-emitting Diodes (OLED), is a new kind to light-emitting component based on semiconductor technology. OLED have many advantages: solid state, active light emitting, high contrast, super thin, low power consumption, no angle restriction, fast respond, wide working temperature range and wide area, etc. Contributed by these advanced properties, OLED technology can not only be used in display area, but also in lighting industry. Many experts believed that once OLED will be a good replacement for LED as the technology matures. In this article we will give a small talk about the global OLED industry.

 

Organic Light-emitting Diodes (OLED), is a new kind to light-emitting component based on semiconductor technology.

 

The earliest development of OLED can be traced back to the 1930s, Dr. Destriau dispersed organic fluorescent compounds within polymers to obtain the first electroluminescent device. But not until 1987, when Tank C W from Kodak created the first OLED (based on small molecule fluorescent materials), this technology has been used in real applications. In 1990, Friend and Burroughes from the University of Cambridge developed a new compound based on OLED technology and named it as polymer OLED (PLED led lights).

 

OLED has a typical sandwich structure of an organic semiconductor layer between two electrodes. Positive electrode are made of ITO, which is a thin and transparent materials that with similar properties as semiconductors. The negative electrode normally used Ca, Al as materials, for the reason that these materials have lower power functions. When voltage applied on both side of electrodes, the organic semiconductor layer will be stimulated and generated photons. The color of rays all depend on the materials that used, usually there are red, green, blue and white rays. In order to obtain higher performance, scientists may add multiple layers within the semiconductor layer, such like holes injected layer (HIL), holes transmit layer (HTL), electron transmit layer (ETL), and electron injected layer (EIL).

 

According to the different organic film materials used in the carrier transporting layer and the light emitting layer, OLED also can be divided into small molecular OLED and macro-molecular OLED. According to different driving method, OLED also can be divided into passive (passive matrix) OLED and active (active matrix) OLED.

 

According to the principle of OLED technology and production process, the entire OLED industry chain can be divided into equipment manufacturing, materials, driver modules, panel and device manufacturing.

OLED technology will become the next breakthrough for LED lighting industry?

Since 2011, export orders from abroad dropped sharply together with a non-fully developed domestic market. Under such circumstance, many downstream LED street light companies intend to find some breakthrough in OLED technology.

 

OLED is an abbreviation of Organic Light-Emitting Diode, also called Organic Electro-luminesence Display, OELD. It has properties of lightweight and energy saving. This technology was firstly applied on displays. In 2003, OLED technology started to use on MP3 and received positive responds. Compare with LED, OLED was a so called new born baby, having strong vitality and cannot-be-underestimated potential. Facing intense competitive, LED producers started to move their attention in this field.

 OLED technology will become the next breakthrough for LED lighting industry?

In accordance with a recent report issued by SME Research Center of Peking University, the total output value of domestic LED industry is around 150 billion yuan in June, 2012. The estimated annual compound growth rate is 25% in next 3 years. The downstream LED applications, like LED displays, LED backing applications, indoor LED lights, will occupy more than 75% market. Indoor LED lights will become the biggest LED lighting market in near future. The estimated annual output value will be 25 billion yuan in 2012 and 100 billion yuan in 2015.

 

Since lacking of the core technique, most LED chips need to be brought from foreign companies. In most indoor lighting products, the chip cost take over about 60% of total cost. Thus, costs of domestic LED products will maintain in a higher level in short period of time. Downstream market is the fiercest in all LED market. The number of new built LED companies sharply growth recently, more and more manufacturer joint into this battle. Many of them were forced to drop prices, and the profit space was shrinking. Professor Peng Jin, secretary-general of Shenzhen semiconductor industry association indicated that those capable downstream enterprises should not only concentrate on overseas market. Presently, they need pay more attention on upstream, establishing their own LED chip Research and Development Department to create their own LED chip technique. Otherwise, “we are working for our competitors.”

 

The development of OLED technology also provided a new profit growth point for domestic LED manufacturers. Mr. Xiaofei Gao, President of LED Industry Research Institute felt confident about OLED’s future development. “Compare with LED, OLED can stimulate more creative to meet more individual needs”.