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What is the principle of LED lighting?

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What is the principle of LED lighting?

If you want to understand the principle of LED light-emitting, you must first understand LED and the structure of LED lights.

Only then can you know how LED emits light. Let’s take a look below!

1.What is LED?

LED is the abbreviation of English Light Emitting Diode, which means light-emitting diode in Chinese. It is ma-de of compounds containing gallium (Ga), arsenic (As), phosphorus (P), nitrogen (N), etc.

2.Structure of LED lights

The core part of the light-emitting diode is a wafer compos-ed of p-type semiconductor and n-type semiconductor. There is a transition layer between the p-type semiconductor and n-type semiconductor, called a p-n junction. As shown in the picture below, it mainly consists of five parts: bracket, silver glue, chip, gold wire, and epoxy resin.

3.LED lighting principle

When current passes through the chip, the electrons in the N-type semiconductor and the holes in the P-type semiconductor violently collide and recombine in the light-emitting layer to produce photons, which emit energy in the form of photons (that is, the light we see).

4.Colorful LED lighting principle

If you want to know the principle of colorful LED light-emitting, first let’s get to know the three primary colors of red (R), green (G), and blue (B).

Other different colors can be obtained by different combinations of these three colors. For example, when red light and green light are lit at the same time, the red and green lights are mixed into yellow.

The color-changing principle of the color-changing lamp is that when two LEDs are lit up respectively through three primary color LEDs, it can emit yellow, purple, and cyan (such as red If the red, green and blue LEDs light up at the same time, they will produce white light.

If there is a circuit that can make red, green, and blue LEDs light up in pairs, individually, and three primary color LEDs at the same time, then it can emit seven different colors of light, so the colorful LED lights appear.

This phenomenon produces different colors depending on the different proportions of their superposition.

What is the difference between expensive LED lights and cheap LED lights?

There are many categories of LED lights, and they can be simply divided into two categories.

One is the light source type, which mainly includes spotlights, downlights, street lights, etc. that serve as lighting functions.

The other type is lanterns, which mainly include chandeliers, special-shaped lamps, floor lamps, etc., which serve as decoration and lighting.

Decorative or finished lamps, the difference between expensive and cheap ones is easy to understand.

For example, they are all chandeliers, one is K9 crystal chandelier, the other is ordinary, and there are even glass, rubber, etc.

The materials are different, and the prices are different. It’s the same, so I won’t go into details.

The poster probably didn’t want to ask this. Today we will talk about the core luminous source and power supply parts of LED lights;

Let’s talk about lamp beads first

Roughly speaking, if you want to explain it in detail, LED is a solid-state semiconductor chip that can convert electrical energy into light energy.

One end of the chip is a P-type semiconductor, and the other end is an N-type semiconductor. When current passes through the wafer, the electrons of the N-type semiconductor will be push to the P-type semiconductor.

When the N-type semiconductor electrons meet the P-type semiconductor electrons, Energy will be emitt-ed in the form of photons, which is the principle of LED lights.

The wavelength of light, that is, the color of light, is determin-ed by the material forming the P-N junction.

The core of the LED light source is the crystal/chip that emits LED light.

After the chip has been manufactur-ed through epitaxy, evaporation, etching, grinding and other manufacturing processes, the number of P-N electrons in the chip, scratches on the P-N electrode, etc.

will result in a difference in the brightness of the conversion rate of the chip from electricity to light. Some have higher conversion rates and are brighter, while others have lower conversion rates, which we call bare crystal brightness.

In addition, each chip has an attenuation degree, which is the change in efficiency of converting electrical energy into light energy within a certain period of time.

The more stable it is, the better. Theoretically, the effective life of the chip can reach 100,000 hours.

After the chip production is complet-ed, there is packaging, that is, the LED chip is ma-de into lamp beads that everyone can see in daily LED lamps.

The function of packaging is to protect the LED chip while transmitting light to the maximum extent and dissipating the heat energy generated by light emission.

Currently, there are pin-type positive and flip-chip processes, COB-type centralized packaging, power-type packaging, etc.

Depending on the packaging process, the final price of LED will be different.

Secondly, the same packaging structure has different final control over heat dissipation and stability, and its price will also be different.

Let’s talk about power supply

LED power supply, also called driving power supply, has only one function, providing stable voltage and constant current power supply to LED lamp beads.

If the operating current of the LED exceeds the rate current or the voltage is unstable, the LED will quickly age and be damage.

LED is a very energy-saving product with low power consumption.

Generally, the working voltage is only a few volts. A few that reach tens of volts are special-purpose lamps.

The current used is also relatively low, generally calculated in milliamps. The lamps we see every day, The wiring is directly connect to the 220V household mains power.

It is first pass through the driving power supply, and then the voltage is stabilize and rectified before being transmitted to the LED lamp bead.

It is divid into isolate and non-isolate. The non-isolate power supply is directly connect to the LED lamp after the voltage is reduce.

The isolated power supply is that the input and output are isolate through a transformer.

There is a process of electrical conversion to magnetic and then electrical conversion. It is relatively safer than non-isolated power supply.

The power supply is high and the cost is also more expensive.

In addition, whether the LED drive power supply has functional guarantees such as short-circuit protection, surge protection, power-off protection, leakage protection, etc. is also a core factor that affects the final price of the lamp.