LED phenomena by humans were first observed 90 years ago. This happened in Russia in 1923, when Oleg Losev first observed the glow of silicon carbide in the radio engineering laboratory of Nizhny Novgorod. Scientific articles on this topic were published in the 30s of the last century, and the first developments appeared only in the 70s. in Leningrad, Zelenograd and Kaluga. The active development of these techniques is associated with the orders of the traffic police for the manufacture of 1000 traffic lights for the 850th anniversary of the capital, in which instead of incandescent lamps brighter green LEDs were used.
The LED is a semiconductor crystal attached to a substrate of aluminum or copper and decorated with an optical system and contact outputs. The SMD LED (surface montage details) differs from other types in that the parts in it are mounted directly on the surface. The crystal structures for this technology are grown by organometallic epitaxy. During this process, within one day, the required structures (chips) can be grown on a maximum of 12 substrates.
Further, the obtained crystals are processed using high technology: the cases are mounted on them, the outputs are made, additional substances are applied, heat removal and the necessary focusing are organized. This stage is very expensive, so SMD LEDs are much more expensive than conventional lamps. It is believed that the cost of one lumen generated by the LED is 100 times higher than the same unit created by a halogen lamp.
The positive characteristics of these systems include low heating, high color purity, lack of infrared and ultraviolet radiation, sufficient strength, durability and safety. Today, the leading country of all where SMD LEDs are manufactured is Japan.
When working with these elements, the following characteristics are usually considered:
- light that can be white (warm or cold), blue, green, yellow or red. White light SMD LEDs are obtained in various ways, including using the RGB method, when different colors are mixed using a lens or other optical system;
- country of origin of the chip (usually Taiwan);
- luminous flux (in lumens);
- required voltage;
- the number of crystals (chips);
- the necessary current strength;
- angle of illumination (from 45 to 140 degrees);
- the presence or absence of a substrate, which is often paid extra.
SMD LEDs are widely used for lighting in a wide variety of areas. They are loved by designers for their high quality of light and electrical safety, and community workers - for their low energy consumption and high vandal resistance. The only exception to the application of these technologies today is the presence of large areas, so they are not used in production. LED strip today can be seen in apartments, cafes and offices, including in rooms with a humid environment, because There are certain types of diodes that are not afraid of water.
The service life of these devices is long enough (up to 50,000 hours for powerful samples), so we can say that SMD LEDs are the best way to illuminate in the future.