Understand LED lights in three minutes

  The light source has gone through the development process of incandescent lamp, fluorescent lamp and LED. LED has the advantages of low energy consumption, high brightness, mercury-free, non-toxic, long life, instant start, and strong plasticity. It has now replaced the traditional light source. This article is not against the traditional The light source does too much retelling,

  The so-called LED is the abbreviation of Light Emitting Diode, that is, light-emitting diode, which is a semiconductor light-emitting material. When a forward voltage is applied to both ends, the carriers in the semiconductor recombine and cause photon emission to generate light. LED can directly emit red, yellow, blue, green, cyan, orange, purple, and white light.

SMD chip lamp beads

  1. An LED light source is composed of brackets, chips, glue, phosphors, and wires

  2. The LED bracket is generally made of copper (also iron, aluminum, ceramic, etc.), because copper has good conductivity, there will be leads inside it to connect the electrodes inside the LED lamp beads.

  3. The high-end light source wires are all 0.999 pure gold wires with diameters of 0.8mil and 1.0mil. Some manufacturers pursuing low prices use copper-doped alloy wires to do it.

  4. Phosphors play a role in adjusting the color temperature of the light source.

  5. Common mid-to-high-end chips are: CREE, Bridgelux, Japan; Nichia, Osram, Germany; Taiwan: Epistar.

Epistar & Corey

Low-end chips: Guangjia, Taigou, Guanghong, New Century, Everlight, Baihong, Guanglei; Mainland China: Mulinsen, Xiamen San'an, Shanghai Blu-ray, Silan Mingxin, Dalian Lumei..... .. (Mainland China now mainly uses Taiwanese chips)

After the LED lamp bead is packaged and formed, the lamp bead can be removed from the bracket, and the copper feet at both ends of the lamp bead become the positive and negative electrodes of the lamp bead, which are used for welding to LED lamps or other LED products.

 common LED light source

The LED models that are commonly circulated in the market are 2835, 5050, 5730, 5630, 3030, 4040, 7030, and integrated COB and high-power lamp beads. The light source models are named after the length and width of the patch. Take the SMD patch as an example, as shown in the figure below It is a 2835 patch, which is 2.8 in width and 3.5 in length. This type of light source is often used in LED bulbs, downlights, spotlights, ceiling lights, light strips, tubes and so on. Each power is about 0.1W-1W more

SMD2835 patch

High-power lamp beads are usually 1W, 2W, 3W each, and are often used in spotlights and outdoor lamps.

High-power LED lamp beads

COB integrated light sources are commonly 5-50W each, and are often used in high-power lamps such as spotlights, track lights and floodlights.

COB integrated light source

LED parameter indicators often said

1. Color temperature: a unit of measurement that indicates the color components contained in the light, the unit is K (Kelvin), the smaller the value, the more reddish the color, the larger the value, the more bluish the color, the middle value is whiter, the normal use of the light color range is about 3000K -6500K, that is, warm white light and positive white light, the most popular neutral light now is about 4000K, (inferior light sources have very large chromatic aberration, common warm white light is reddish, and white light is blue)

Color temperature comparison table

2. Luminous efficiency: The ratio of the luminous flux emitted by the light source to the power consumption is called luminous efficiency, and the unit is LM/W (lumens/watt). Different light sources emit the same luminous flux, and the less power they consume, the higher the luminous efficiency.

3. Brightness: Defined as the brightness of the light source unit, that is, the luminous intensity per unit projected area. The unit of brightness is candela/square meter (cd/m2). Brightness is how people feel about the intensity of light. It is a subjective quantity.

4. Illuminance: Refers to the luminous flux of visible light received per unit area. Unit Lux (Lux or lx). It is used to indicate the intensity of the light and the amount of the surface area of the object being illuminated.

Illumination diagram

5. Color rendering index: (The simplest understanding is to restore the true color of the item. The higher the color rendering index, the more true the color is reflected. Generally, the color rendering index of high-quality LED light sources can reach more than 85, and the definition of daylight and incandescent lamps is 100) . The color rendering ability of a light source to an object is called color rendering, which is compared with the appearance of the object under the same color temperature or reference light source (incandescent lamp or daylight). The content of the spectrum emitted by the light determines the light color of the light source,

Schematic diagram of color rendering index

6. Luminous decay: LED luminous decay means that after a period of time when the LED is lit, its luminous intensity will be lower than the original luminous intensity, and the lower part is the LED luminous decay. According to international practice, the luminous decay is 30%. If the product is determined to be invalid, many inferior products have exceeded this value in less than half a year. There are many factors that affect the light attenuation. The quality of the light source itself, the driver, and the heat dissipation are all important factors that affect the light attenuation.

Factors affecting the quality of LEDs

1. The pros and cons of the selected raw materials.

2. Whether the packaging process is perfect (there is no dust, the components fit perfectly), and the heat dissipation copper pad material.

Six: Life: The theoretical life of high-quality LED is 100,000 hours

Why the life of LED lamps is short or even less than one year? There are many factors related to the life of the lamps, such as the quality of the driving power, the matching degree of the driving power and the light source, and the assembly process of the lamps.

Today, I introduced the LED light source. I believe everyone has a preliminary understanding of the LED light source. When buying LED lamps, everyone boldly asks "Boss, what chip do you use for the lamp?" There may be unexpected gains, don't you believe it? you try. Shopping guides will not be confused when introducing a lot of professional terms. Have you learned how smart you are?

The working principle of LED lamps will be updated below. After understanding, you can DIY your own personalized lamps. Remember to follow, like, share, manual codewords are not easy, your support is my biggest motivation for updating.