The development trend of optical films for backlight modules is similar to that of LCDs: both will tend to develop towards higher brightness, thinner design, lighter weight, and wider color gamut.
According to statistics and predictions from Display Search, with the continuous growth in global demand for liquid crystal modules, the global market demand for optical films used in liquid crystal displays will also show a steady growth trend. It is expected that in 2017, the global market demand for optical films used in backlight modules of liquid crystal displays will reach 720 million square meters. Among them, the market demands for reflective films, diffuser films, brightness enhancement films, microlens optical films, and dual brightness enhancement films will reach 184 million square meters, 184 million square meters, 204 million square meters, 76 million square meters, and 71 million square meters respectively.
Optical films for backlight modules include reflective films, light guide plates, diffuser films, brightness enhancement films, composite films, quantum dot enhancement films, reflective incremental composite films, etc. Their technology utilizes optical microstructures and scattering particles to redistribute light energy and achieve specific application purposes.
The most important function of the diffuser film is to provide a uniform surface light source for liquid crystal displays, and it also has a certain effect of increasing brightness, referred to as BEF for short. It is a key component in the TFT-LCD backlight module. It is an optical film with a uniform prism pattern precisely formed on the surface of highly transparent PET using acrylic resin.
With the continuous increase in global demand for liquid crystal modules, the global market demand for diffuser films used in liquid crystal displays will also show a steady growth trend. It is expected that by 2017, the global market demand for diffuser films used in backlight modules of liquid crystal displays will reach 290 million square meters, an increase of 20 million square meters compared to 2016, with a growth rate of approximately 7%.
Simply put, an optical composite film integrates two or more optical functions into a single film. It is driven by several of its development trends and demands: currently, liquid crystal display screens are becoming larger and larger, pursuing both thinness and lightness, as well as brightness effects. The advantages of composite films lie in their small thickness and low cost, while their disadvantages include a decrease in brightness (due to damaged prism peaks leading to reduced light-gathering ability; adhesives absorbing part of the light) and increased manufacturing difficulty.
Brightness-enhancing polarizers can reuse the light loss of polarizers, recovering at least 50% of the light loss.
2017 is the first year of quantum dots. Recently, people have begun to come into contact with this term. Ordinary liquid crystal displays have many quantum dot upgraded products, but what is the real meaning of such products? In fact, current quantum dot TVs are a type of liquid crystal TV plus quantum dot backlight films; they are essentially liquid crystal TVs. Of course, quantum dots themselves can emit light, so in fact, imaging can be achieved using only quantum dot materials, but such products are still very immature at present.
Quantum dots are nanoscale fluorescent materials with inherent luminescent properties. The quantum dots in quantum dot wide color gamut films generate red and green light when irradiated by a blue LED backlight, and mix with part of the blue light transmitted through the film to produce white light.
Although the QLED camp continues to emphasize that color saturation is better than OLED and there is no issue with service life, at this stage, due to poor external quantum efficiency and difficulty in maintaining long-term luminescence, truly self-luminous QD displays are still difficult to reach a commercial level.
Therefore, in the short term, the QLED camp will still rely on QD backlight products to compete, that is, laying a film full of quantum dots on the backlight, commonly known as QDEF.
By leveraging the luminescent properties of quantum dots to improve color gamut and backlight efficiency, the color and brightness of the screen are enhanced, resulting in color effects that are at least 30%-50% better. However, since the backlight is an essential component, it will increase the overall thickness of the device, so the advantage compared to OLED TVs is not obvious. Therefore, the new generation of QLED TVs may adopt glass light guide plate solutions to reduce thickness.
According to data from industry chain surveys, the current price of overseas quantum dot films is 80-100 US dollars per square meter, and the unit price of domestic quantum dot films is around 60 US dollars per square meter. It is expected that with the expansion of production capacity and improvement of processes, the price reduction of quantum dot raw materials and films is a major trend. The cost reduction will drive the continuous improvement of the penetration rate of quantum dot TVs. Based on industry chain understanding and calculations, it is judged that the price of quantum dot films will stabilize at around 20 US dollars per square meter in about 3-5 years. With the decrease in its cost, it is highly likely to be promoted and popularized in the market in the future.
