A light-emitting diode, like a normal diode, consists of a PN junction. After energization, the holes injected from the P region into the N region and the electrons injected into the P region from the N region are recombined with the electrons of the N region and the holes of the P region within a few micrometers near the PN junction to generate spontaneous emission fluorescence.
The energy states of electrons and holes in different semiconductor materials are different. The energy released when the holes are recombined is different, and the wavelengths of the emitted light are different, thus showing different colors.
Light Emitting Diode is simply referred to as LED. It is made of a compound containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N), or the like.
When electrons and holes recombine, they can radiate visible light, and thus can be used to make light-emitting diodes. Used as an indicator light in circuits and instruments, or as a text or digital display. The gallium arsenide diode emits red light, the gallium phosphide diode emits green light, the silicon carbide diode emits yellow light, and the gallium nitride diode emits blue light. Organic light-emitting diodes OLED and inorganic light-emitting diode LEDs are further classified by chemical properties.
principle
It is a type of semiconductor diode that converts electrical energy into light energy. Like ordinary diodes, LEDs consist of a PN junction and also have unidirectional conductivity. When a forward voltage is applied to the light-emitting diode, holes injected from the P region into the N region and electrons injected into the P region from the N region are respectively separated from the electrons of the N region and the P region within a few micrometers near the PN junction. The hole complexes to produce fluorescence of spontaneous radiation. The energy states of electrons and holes in different semiconductor materials are different. When the energy released by the recombination of electrons and holes is different, the more energy is released, the shorter the wavelength of the emitted light. Commonly used are diodes that emit red, green or yellow light. The reverse breakdown voltage of the LED is greater than 5 volts. Its forward volt-ampere characteristic curve is very steep, and a current limiting resistor must be connected in series to control the current through the diode. The current limiting resistor R can be calculated by:
R=(E-UF)/IF
Where E is the supply voltage, UF is the forward voltage drop of the LED, and IF is the normal operating current of the LED. The core of the LED is a wafer consisting of a P-type semiconductor and an N-type semiconductor. There is a transition layer between the P-type semiconductor and the N-type semiconductor, called a PN junction. In some PN junctions of semiconductor materials, the injected minority carriers recombine with the majority carriers to release excess energy in the form of light, thereby directly converting electrical energy into light energy. The PN junction adds a reverse voltage, and minority carriers are difficult to inject, so they do not emit light. Such a diode fabricated by the principle of injection electroluminescence is called a light-emitting diode, and is generally called an LED. When it is in the forward working state (ie, the forward voltage is applied to both ends), when the current flows from the anode of the LED to the cathode, the semiconductor crystal emits light of different colors from ultraviolet to infrared, and the intensity of the light is related to the current.
Led is also called organic light-emitting diode, which uses the current flowing forward through the diode to emit light. When a forward voltage is applied to the PN junction of the light emitting diode, the PN junction barrier is lowered, and the diffusion motion of the carrier is greater than the drift motion, so that holes in the P region are injected into the N region, and electrons in the N region are injected into the P region. When the mutually injected holes meet with electrons, they will recombine, and most of the energy generated during recombination will appear in the form of light, and thus emit light.
Different diodes emit different colors because they have different materials inside (the wavelength of the luminescence is different). For example, a gallium arsenide diode emits red light, a gallium phosphide diode emits green light, and a silicon carbide diode emits yellow light. The white light is a combination of orange and blue or red, green and blue. The material inside the fine adjustment can also change the wavelength of the light and fine-tune the color, such as emerald green, light red, light blue, etc.
In the semiconductors that were not called very much, electrons and holes were in love under the influence of external forces, and they got married. The result was passionate, the crystal of happy life - photons ran out because of their different heights - wavelength Let you see different colors, green, red, yellow, blue, and so on. . . This is the principle of LED lighting, and why the light produced has a different color.
It uses the current flowing forward through the diode to illuminate. When a forward voltage is applied to the PN junction of the light emitting diode, the PN junction barrier is lowered, and the diffusion motion of the carrier is greater than the drift motion, so that holes in the P region are injected into the N region, and electrons in the N region are injected into the P region. When the mutually injected holes meet with electrons, they will recombine, and most of the energy generated during recombination will appear in the form of light, and thus emit light.
--Shenzhen Toplight lighting Co. Ltd.(led tube light/
LED linear light/led high bay light/led tri-proof light/Toplight/Toplight Lighting)
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