Prism

Today, the prism film has become an indispensable raw material for handheld devices in liquid crystal display devices. The following diagram shows a backlit structure of a mainstream mobile phone LCD display in which not only the prism film (TBEF / TBEF II -Ti / TBEF II -Mi) based on micro-replication technology is used, Membrane technology, reflectivity of 99% or more of the reflective film (ESR), and also combined with micro-replication technology and multi-layer BEF in the application of mobile phones (BEF-RP / BEF-RP IIr / BEF-RP II). Among them, TBEF is the abbreviation of Thin Brightness EnhancementFilm, is a prismatic brightening film, using 3M's unique micro-replication technology, the acrylic resin made of prism structure made on the PET substrate, the formation of a total thickness of only 60 ~ 65 micron prism diaphragm. In the notebook application of the prism in the notebook monitor is also the most popular applications, the most commonly used is BEFII material. According to the specific requirements, in the notebook's LCD screen can choose to use a prism or two ortho-placed prism. BEFII in notebook LCD display applications When the light emitted through the lower diffusion sheet passes through the prism film, it is collected in the axial direction. BEF II brightening effect map As shown above, after using a BEFII, the brightness angle will be reduced, but the relative center of the brightness and visual range of brightness will be about 50% increase. After using two orthogonal BEFIIs, the brightness angle will be further reduced, the viewing range will be closer to the central axis, while the center point brightness will be about 110% increase. Thus, the effect of increasing the brightness within the visible range is achieved. The use of displays and televisions is usually due to the fact that the brightness of the display and the television is greater than that of the notebook, so that only one prism is usually used. In large-size LCD modules, 3M is usually recommended to use BEFIII series of prism film. BEFIII compared to BEFII, from the perspective of its prism is not the same size of the micro-prism structure.

    Mirror film is the use of 3M micro-replication technology, the acrylic resin made of prism structure made in the PET substrate made of optical film, the surface is a height of 20 to 50 microns micro-prism structure. In accordance with the principle of geometrical optics, the light emitted by the backlight through the prism film and backlight system of the cycle, the final convergence in the face of the direction of the exit, so as to achieve brightening effect.

Product structure and working principle    When the diaphragm is used in the backlight, the light entering from the light source passes through the prism structure, and only the light of the incident light within a certain angle range can be emitted by the refraction, and the remaining light does not satisfy the refraction And is reflected by the edge of the prism back to the light source, and then by the bottom of the light source of the role of reflection and re-exit. In this way, the light in the backlight under the action of the prism structure, the continuous recycling, the original direction to the divergence of light through the prism film, was controlled to 70o angle range, so as to achieve the effect of axial brightness enhancement. According to the test, BEF series of bright film leaflets effective penetration rate increased by about 60%. 
Invention story    ordinary into the magical brightness enhancement film BEF: a winter of twenty years ago, a basement in Quebec, Canada, a 3M researchers are experimenting. Due to the high latitudes of the northern hemisphere, the winter sun is hanging above the horizon all day long. So he invented a glass with a prism catheter, oblique sun into the catheter after the end of the catheter will spread along the wall, the whole tube like a light through the body, the basement suddenly bright a lot.
BEF invented story illustrations    Later, 3M used thin film technology to produce this light pipe. In many years, the application of this prism catheter has been limited to the lighting or decoration of the building, only a small amount of sales each year.     In the nineties of the twentieth century, with the popularity of notebook computers, liquid crystal display technology began to develop rapidly. However, due to the unique characteristics and structure of the LCD panel, the utilization of light is very low. How to increase the brightness of liquid crystal display has been plagued by the difficulties of researchers.     But also a very occasional whimsy, 3M scientists found that if the prism catheter cut, tiled in the LCD backlight, you can play the role of condenser, so that the brightness of the LCD screen is much larger improve. After a period of research and development, 3M combined with micro-replication technology and thin film technology, to further optimize the product, so that the effect is more significant, and named BoF (BrightnessEnhancement Film).     But how to allow customers to accept this new product? 3M engineers bought the same two of the best laptops on the market at the time. One of the two with two prism direction perpendicular to the BEF, its brightness even more than doubled the original!     When two computers were placed in front of their manufacturers, they were soon convinced. From this day on, BEF began its magical journey, widely used in small to mobile phones, PDA, large computer monitors, LCD TVs and other liquid crystal display products.