LED lighting and OLED lighting difference
LED and OLED as a new type of semiconductor lighting technology, is called the fourth generation lighting source or a green light, compared to the traditional lighting products, it has the advantages of energy saving, environmental protection, long life, small size and other characteristics, can be widely applied to various instructions, display, decoration, back light source, general lighting and city night scene etc.. Therefore, in recent years in the world, some developed countries are active in the development of LED and OLED semiconductor lighting. However, LED and OLED due to the working principle and the production process, the existence of their own characteristics.
LED name is led, the general use of group III-IV inorganic semiconductor material and chemical vapor deposition ( CVD ) manufacturing process. As a traditional semiconductor industry, its process and high cost, difficult to achieve large size of. Therefore, LED can only be used in the form of point light source. In the universal interior lighting field, in order to achieve a certain space lighting brightness, LED requires very high brightness, so in order to prevent glare, soft light, LED often must use with shade. But then, LED light emitting efficiency will descend too. If you want to use LED to make a surface light source, such as LCD backlight, requires a combination of multiple LED and paired with the light guide plate and other complex optical system. In addition, the luminous efficiency of LED with temperature rising and decline. Because LED has very small volume, resulting from the operation of heat to the timely dissemination out, so it must be equipped with heat radiating device for LED lamps. Based on the above a few reasons, LED light source technology advantages such as lightweight, luminous efficiency and cost advantages, in the production of a lamp will be greatly discounted.
The current white LED is generally using blue LED covered phosphorescent powder mode ( as shown). Phosphor is excited by the blue light LED issued will generate yellow light, and LED itself and common mixed white light blue. While this approach is of low cost, but there are many disadvantages. On one hand, this way to produce white light color rendering index will not ideal, namely the under white light illumination object color will appear deviation, so that it is suitable for application in color, high quality requirements of the occasion; on the other hand, phosphorescent powder blue LED a lot faster than the aging, causes a white to blue drift, shorten life.
OLED is an organic light emitting device, as the name suggests, OLED is based on the organic semiconductor material production device. OLED materials used are small molecules and polymers, at present industrialization mainly to small molecular organic materials. Because of the small molecule OLED using low cost glass as substrate, a large area of vacuum thermal evaporation film-forming process, so OLED is congenital surface light source technology. OLED process without LED process of ultra high vacuum and high temperature environment, cost competitiveness of higher. Organic material theory than inorganic semiconductor material is much lower, only is currently limited to industrial scale and in the production of the material utilization rate and other factors, the cost is still very high in organic material. However, with the enlargement of the industry scope, organic material costs will be substantially reduced.
OLED generally uniform light and soft, close to the Lang Park ( Lambert ) distribution of radiation, so the OLED itself is almost like a lamp with lampshade, without the need to use. At present, white OLED mainly red green ( yellow ) blue three basic color organic material are sequentially superposed blend. In addition, organic materials luminescence spectrum is characterized by its half peak width is very wide, so white OLED spectrum does not have a larger gap, which makes the OLED light source color index is very good, especially suitable for indoor general lighting, and even the professional photography application. Moreover, through the adjustment of each color of light emitting material proportion, can produce any color of light, to adapt to different applications.
Because OLED has very large light-emitting area, work can generate heat emanates, without the need for heat radiating device. So OLED can be extremely thin, space saving cost. In addition, the OLED can be designed into various shapes, greatly expanding the OLED lamps in applications in the field of space art decoration. OLED killer can be transparent characteristic, and can realize the traditional lamp completely unthinkable applications, such as OLED production in a glass window, the day to allow natural light transmission in the evening, for illuminating lamps.
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