Since the emergence of external lighting, we have divided lighting into three eras:
the era of filament bulbs (incandescent lamps), the era of gas bulbs (fluorescent
lamps), and the era of semiconductor luminescence (LEDs). And among them, the
longest history incandescent lamp and the future mainstream LED are the most
important points of investigation. No matter how the times develop, the production
process of the lighting industry has astonishing similarities, except that China is
also in the downstream of the industry. The core technologies are mostly owned by
countries and regions such as Europe, America, and Japan.
The principle of LED emission is that when electrons pass through a layer of
semiconductor material, they excite the semiconductor material to convert electrical
energy into light energy. However, the luminescence ability of single-layer
semiconductors is weak, so many layers of single-layer materials need to be stacked
together and pressed into a composite material similar to a thousand layer cake,
which is called an "epitaxial wafer".
So, the luminous efficiency of LED depends on how many layers can be pressed in at
the same thickness. The thinner the single-layer material, the more layers it can
stack, and the higher the luminous efficiency. Nowadays, 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, but the difference is that the cut epitaxial wafer is square shaped.
Due to the special structure of epitaxial wafers, it is very difficult to cut the
luminescent core completely and without damage. Not only does it require a vacuum
environment, but also a professional cutting machine. Currently, there are only two
manufacturers in the world producing this type of cutting machine.
3. Place the core into the LED chip: The chip is to the LED, just as the lamp holder
is to the light bulb, it is the power supply part. Chips are very important
equipment for achieving the desired effect of LEDs, as LEDs have very high
requirements for current.
4. Encapsulating LED chips into luminous bodies: Encapsulating LED chips into
luminous bodies is like adding lampshades to a filament lamp holder to make a light
bulb. The shape of the lampshade can vary according to the requirements, but the
packaging technology determines the service life of the luminous body.
4. Encapsulating LED chips into luminous bodies: Encapsulating LED chips into
luminous bodies is like adding lampshades to a filament lamp holder to make a light
bulb. The shape of the lampshade can vary according to the requirements, but the
packaging technology determines the service life of the luminous body.
5. Lighting application: Just like using incandescent bulbs, assemble them into
different LED products 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. These issues require us to use more energy to overcome
them.