The difference between LED and OLED

LED and OLED as a new semiconductor lighting technology, known as the fourth generation of lighting or green light source, compared with traditional lighting products, it has the characteristics of energy saving, environmental protection, long life, small size, and can be widely used in various instructions , display, decoration, backlight, general lighting and city night scenes.

Therefore, in recent years, some developed countries in the world are actively developing LED and OLED semiconductor lighting. However, LED and OLED have their own characteristics because of their different working principles and production processes.

led

The full name is a light emitting diode, which is generally manufactured using a III-IV inorganic semiconductor material and a chemical vapor deposition (CVD) process. As with the traditional semiconductor industry, its process costs are high and it is difficult to achieve large size.

Therefore, LEDs can only be used in the form of point light sources. In the field of indoor general lighting, in order to achieve lighting brightness in a certain space, the LED needs a high light-emitting brightness, so in order to prevent glare and produce soft light, the LED often needs to be installed with a lamp shade. However, as a result, the luminous efficiency of LED lamps will also decrease.

If you want to use LED to make a surface light source, for example, as the backlight of the LCD, you need to combine multiple LEDs with a complex optical system such as a light guide plate. In addition, the LED's luminous efficiency will drop rapidly with increasing temperature.

Due to the very small size of the LEDs, the heat generated during operation is difficult to dissipate in time, so the LED lamps must be equipped with heat sinks. Based on the above reasons, the advantages of LED light source technology, such as luminous efficiency, lightness and thinness, and cost advantages, will be greatly discounted after being made into lamps.

Currently, white LEDs are generally implemented by using blue LEDs to cover phosphor powders. Phosphor powder excited by the blue light emitted by the LED will produce yellow light, and then mix with the LED's own blue light white light. Although this method is low in cost, it has many disadvantages.

On the one hand, the color rendering index of white light generated by this method will be unsatisfactory, that is, the color of the object under the irradiation of white light will be deviated, making it unsuitable for applications where the color quality requirements are high; on the other hand, the phosphor powder It will burn out much faster than a blue LED, which will cause the emitted white light to drift toward blue and shorten its life.

OLED

The full name is an organic light emitting device. As its name implies, OLED is a device based on organic semiconductor materials. The materials used for OLEDs are small molecules and macromolecules. Currently, industrialization is mainly based on small-molecule organic materials.

Since small-molecule OLEDs use low-cost glass as a substrate and are manufactured by a large-area vacuum thermal evaporation film formation process, OLEDs are innate surface light source technologies. The OLED process process does not require the ultra-high vacuum and high temperature environment of the LED process technology, and the cost competitiveness is much higher.

Organic materials are theoretically much lower than inorganic semiconductor materials. However, due to factors such as industrial scale and material utilization in production, the cost of organic materials is still high. However, with the expansion of industrial scale, the cost of organic materials will drop significantly.

OLEDs generally emit light evenly and softly, which is close to the distribution of lambert radiation. Therefore, the OLED itself is almost a lamp and does not need to be used with a lamp shade. Currently, white light OLEDs are mainly formed by superimposing organic materials in three basic colors: red, green and yellow.

In addition, organic materials emit light spectrum is characterized by a wide half-width, so there is no large gap in the white OLED spectrum, which makes the OLED light source color rendering index is very excellent, especially suitable for indoor general lighting, and even professional photography And other applications. Moreover, by adjusting the light-emitting ratio of each color material, any shade of light can be generated to suit different applications.

Because OLEDs have a very large light emitting area, the heat generated during operation can be dissipated in a timely manner without the need for a heat sink. So OLEDs can be very thin and light, saving space costs. In addition, OLED can be designed into a variety of shapes, greatly expanding the application space of OLED lamps in the field of art and decorating.

The OLED killer's transparent features can even achieve applications that traditional lighting cannot completely imagine. For example, OLEDs can be made on window glass, let natural light transmit in during the day, and be used as lighting fixtures at night.