LEDs (light-emitting diodes), also bearing the more familiar English name LED (an abbreviation for light-emitting diode), are real unsung heroes in the world of electronics. They perform dozens of different functions and are now used in almost every electronic device. So, for example, they display symbols on light displays, transmit information from the remote control to the signal receiver, light at home or inform you about the current status of the device. The green, red and blue LEDs assembled together can form an image on a huge television screen or control traffic at a traffic light.
Shines but does not warm
In principle, LEDs are just miniature bulbs that fit perfectly into any electrical circuit. But at the same time, they do not have an incandescent filament, which is mandatory for ordinary lamps, as a result of which they are slightly heated. The light emitted by LEDs arises only as a result of the movement of electrons in a semiconductor, respectively, and their life is the same as that of a conventional transistor.
If we compare the service life of an LED and an incandescent lamp, then LED has thousands of hours more. Tiny LEDs have replaced tubes that illuminate high-definition LCDs, making them much thinner.
Where did this strange light come from?
Without delving into the jungle of physical processes, let us see how the LED is lit.
Light is a form of energy released by an atom, consisting of many small packets of particles with energy and momentum, which are called photons. They are produced when electrons move from a distant orbit to a closer one. The greater the distance traveled by an electron, the greater the energy of a photon emitted by it, characterized by a higher frequency. This frequency is precisely responsible for the length of the light wave, which determines the color of the radiation. For example, the atoms in a standard silicon diode are arranged in such a way that the electron falls over a relatively short distance. As a result, the photon frequency is so small that it is invisible to the human eye - it is in the infrared part of the light spectrum. Of course, this is not necessarily bad: infrared LEDs are ideal, in particular, for remote controls.
LEDs burning in red open a segment of light visible by a person and are already able, for example, to highlight numbers in an electronic clock. Depending on the materials used in the LEDs, they can be configured to glow in the infrared, ultraviolet and all colors of the visible spectrum between them.
Two of the casket, identical from the face
Shortly after the development of the red LED, LEDs and other colors appeared. Almost immediately, they began to be combined, placing in a single shell. A two-color LED is a device with two leads, where two oppositely directed diodes of different color radiation are installed in parallel in one housing. In this case, the color will depend on the polarity of the voltage supplied to the device.
Widely used are red-green LEDs used as an indicator of the device's readiness for operation (red on - off, green - on).
There is no perfection in the world, or a couple of shortcomings of an ideal light source
Obviously, LED technology is still imperfect. One of the drawbacks is their vulnerability to high temperatures. Excessive current flow and, as a result, overheating of the LED circuit cause permanent burn-out, often called LED fusion. In addition, until recently, LEDs based on advanced semiconductor materials were too expensive to use as natural light. But since the 2000s, with the launch of mass production, the price of LEDs has fallen several times and has become commensurate with the cost of conventional lamps, and given the long life, bright light, environmental friendliness and amazing energy efficiency, the use of LEDs has become a more economical option for lighting for the home .
Great and terrible red lantern
Let us dwell in more detail on where the red LED found application. It can rightfully be considered the "big brother" in the LED family, if only because it was the first LED operating in the visible radiation spectrum. Naturally, they began to apply it for practical needs earlier than others, and first of all to attract attention in case of equipment malfunction. Agree, when instead of the uniform rumbling of the engine, the red LED blinks rhythmically, highlighting one or another icon on the panel of your favorite car or a beloved washing machine, then at least this causes a feeling of slight alarm. Yes, it is for warning of such emergencies that they most often use an indicator of this type.
The mystery of red
Red color has the longest wavelength and is less susceptible to scattering, respectively, it is visible from the farthest distance. Therefore, it is not surprising that the flashing red LED is widely used for emergency and alarm lights. Moreover, the level of energy consumption of LEDs of this color is the smallest among all other LEDs in the visible spectrum, which ensures maximum operating time of the used lighting device.
It is customary to use red LED lights where there is a need for high-intensity light, while not disturbing other people. For example, they are preferred in the theater, in the cinema, and for reading astronomical maps. Red light does not strain the eyes, contributing to better dilatation of the pupils, and allows you to perfectly see objects that reflect light.
And LED gardeners have found worthy application in gardeners. Blue light stimulates the initial growth of the plant, and the use of red LEDs improves the process of flowering and fruit set. Here, LEDs are unrivaled because, emitting a huge amount of light, they do not overheat and do not dry the air, in contrast to lamps of another type, which can harm the future crop.
The farther, the "more wonderful"
Replacing old incandescent bulbs with LED bulbs is just the tip of the iceberg, the LED story is just beginning. Thanks to new developments, LED solutions are entering new horizons that were previously inaccessible to them. The most likely development trend associated with the use of organic LEDs, or OLED.
The organic materials used to create these semiconductors are plastic, which makes it possible today to create samples of flexible light sources and even displays. It seems that OLED technology will pave the way for the next generation of televisions and smartphones. After all, it’s really convenient to remove your TV from the wall, turn it into a tube and take it with you, let’s say, to the cottage.
It's hard to say where LED technology will go in the future, but one thing is clear - there will be no return to Edison's bulb.