Five steps in producing LED lighting products

Since the emergence of external lighting, we divide lighting into three eras: the filament bulb era (incandescent lamp), the gas bulb era (fluorescent lamp), and the semiconductor light-emitting era (LED). Among them, the incandescent lamp with the longest history and the LED, the mainstream in the future, are the most important points for investigation. No matter how the era develops, the production process of the lighting industry is surprisingly similar, except that China is also at the downstream of the industry. The core technology is basically owned by countries and regions such as Europe, the United States, and Japan.

1. The principle of LED light emission is that when electrons pass through a layer of semiconductor material, they stimulate the semiconductor material to convert electrical energy into light energy. However, the light emission ability of a single layer of semiconductor is very weak, so many layers of single layer materials must be stacked up and pressed into a composite material similar to a thousand-layer cake, which is the "epitaxial wafer".

Therefore, the luminous efficiency of LEDs is determined by how many layers can be pressed into the same thickness. The thinner the single layer of material is, the more layers can be stacked, and the higher the luminous efficiency is. Currently, the thickness of each layer is generally only 2-20 microns, which also determines that epitaxial wafer production is the most difficult part of the entire LED production process.

2. Cutting - LED core: It is equivalent to extracting the filament from the tungsten wire material. The difference is that the epitaxial wafer is square after cutting.

Due to the special structure of the epitaxial wafer, it is very difficult to cut out the light-emitting core intactly. Not only does it require a vacuum environment, but it also requires a professional cutting machine. Currently, there are only two manufacturers in the world that produce such cutting machines.

3. Put the core into the LED chip: The chip is to the LED as the lamp holder is to the light bulb, which is the power supply part. The "chip" is a very important equipment to achieve the ideal effect of LED, because LED has very high requirements for current.

4. Encapsulate LED chips into luminous bodies: Encapsulate LED chips into luminous bodies, just like adding a lampshade to a filament lamp holder to make a light bulb. The shape of the lampshade can be different according to the needs, but the encapsulation technology determines the service life of the luminous body.

5. Lighting application: Just like using incandescent bulbs, different LED products can be assembled according to different functions and needs.

For LED lighting, the first three steps of epitaxial wafer, cutting and chip are upstream, the fourth step of packaging is midstream, and the fifth step of application is downstream. We need to use more energy to break through these problems.