The Process Of Light Guide Plates Manufacturing
In order to understand the manufacturing process of light guide plate, we should know the parts and materials which are necessary for the light guide plate in advance.
a. Injection molding: optical PMMA particles, inks
b. Cutting forming: optical PMMA plates, inks
2. Optical PMMA particles and plates:
No matter what kind of manufacturing plan is proceeded to produce the light guide plate, the most important and original material is optical PMMA (POLYMETHYL METHACRYLATE), which is also known as acrylic or plexiglass. And it can be divided into PMMA particles and PMMA plates. The MMA monomers which are extracted from petroleum have been chemically processed to make optical PMMA particles. The optical PMMA particles which can be used by injection molding have been made into optical PMMA plates by method of Casting or Injection. There are some famous PMMA manufacturers, such as: (Japan) Mitsubishi Rayon, (Japan) Sumitomo Chemical Sumitomo, (Japan) Asahicasei, (Japan) Kula Lei Kuraray, (Taiwan) Chi Mei chemical, (Korea) World and Sehwa.
3. Ink: It is divided into ultraviolet (UV) and infrared (IR).
4. There are three main steps of cutting the light guide plate.
Step one: polish the luminous surface of the acrylic plate and then cut the acrylic plate into the form we need.
Step two: make the light guide lattice points according to the design.
Step three: clean the acrylic plate and then print the light guide points on it. Finally, dry the plate by infrared or ultraviolet.
5. Injection molding light guide plate is divided into printed light guide plate and non-printed light guide plate, whose process is basically the same as the casting mold. Non-printed light guide plate is that light guide points which have been designed are cast in the mold, and both light guide points and light guide plate are done in the final process of injecting mold. Printed light guide plate is that light guide points are printed after the acrylic plate has been injected.
Here, let’s see some photos in our factory.
These are the original acrylic plates which are very large, about 3.5*1.5 meter. The common specifications of the thickness are 1.0 mm, 1.5 mm, 2.0 mm, 2.5 mm,3.0 mm, 3.5 mm, 4.0mm, 5.0mm.
This is our new cutting forming machine for acrylic plates.
This is a front view picture of a working cutting forming machine.
This is a side view picture of a working cutting forming machine.
The light guide lattice points we design for the acrylic plates are carved into this transparent plate. And then light guide lattice points are printed on the surface of acrylic plates by silk-screen printing.
We often hear from our customers complain about why they need a dedicated plastic mold for a LED backlight. A dedicated light guide plate mold at least costs one thousand dollars. In fact, it is quite necessary. It not only can make light guide plates into irregular shapes and keep the shape the same from beginning to the end, but also increase the light transmittance and enhance the brightness.
We can see that there are some dedicated light guide plate molds in the photo. In fact, they are very heavy and made from steel. I have tried to lift one up, but didn’t succeed.
This is the injection molding machine of making light guide plates, it is pretty huge and has a very high working efficiency.