What is prism film?
Jul 26, 2018
The prism film is an optical film manufactured by using a 3M microreplication technique to fabricate a prism structure made of an acrylic resin on a PET substrate, and has a microprism structure having a height of about 20 to 50 μm. According to the principle of geometric optics, the light emitted by the backlight passes through the circulation of the prism film and the backlight system, and finally converges in the front view direction to achieve the brightening effect.
Product structure and working principle
When the diaphragm is used in a backlight, when the light incident from the light source passes through the prism structure, only the light of the incident light within a certain angular range can be emitted by the refraction, and the remaining light does not satisfy the refractive condition. It is reflected back to the light source by the edge of the prism, and then re-exposed by the reflection sheet at the bottom of the light source. In this way, the light in the backlight is continuously recycled under the action of the prism structure, and the light originally diverging in various directions is controlled to an angle range of 70° after passing through the prism film, thereby achieving the effect of enhancing the axial brightness. According to the test, the effective penetration rate of the BEF series brightness enhancement film is about 60%.
Invention story
A magical brightening film BEF: A winter in Quebec, Canada, a 3M researcher is experimenting in a winter in Quebec, Canada. Due to its high latitude in the northern hemisphere, the winter sun hangs above the horizon all day low. So he invented a glass tube with a prism. When the oblique sunlight hits one end of the tube, it will propagate along the wall of the tube. The whole tube will illuminate like a tube, and the basement suddenly brightens.
BEF invention story illustration
Later, 3M used thin film technology to produce such a light pipe. For many years, the use of such prismatic conduits has been limited to the lighting or decoration of buildings, with only a small amount of sales per year.
In the 1990s, with the popularity of notebook computers, liquid crystal display technology began to develop rapidly. However, due to the unique characteristics and construction of the liquid crystal panel, the light utilization rate is low. How to increase the brightness of liquid crystal display has always been a problem that plagues researchers.
It is also a very accidental whimsy. 3M scientists found that if the prismatic catheter is cut open and tiled on the LCD backlight, it can play a role of concentrating, so that the positive brightness of the LCD screen is greatly increased. improve.
After a period of research and development, 3M combined with micro-replication technology and thin film technology, further optimized this product to make its brightening effect more remarkable, and named it BEF (Brightness Enhancement Film).
But how do you let customers accept this new product? 3M engineers purchased the same two of the best laptops on the market at the time. Adding one of the two BEFs with two prisms perpendicular to each other, its brightness has more than doubled!
When such two computers were placed in front of its manufacturers, they were quickly convinced. From this day on, BEF began its magical journey, which is widely used in various liquid crystal display products such as mobile phones, PDAs, computer monitors, and LCD TVs.
A
