What is Quantum Dot Film？

Quantum dot film is a relatively new technology that is starting to gain popularity in the world of display manufacturing. So what is quantum dot film, and how does it work? In this blog post, we will discuss the basics of quantum dot film and how it is made. Stay tuned for future posts that will go into more detail about the benefits of using quantum dot film in displays!

Quantum dot concept and principle

Quantum dots: quantum do is actually a nanoscale semiconductor, by applying a certain electric field or light pressure to this nano semiconductor material, they will emit a specific frequency of light, and the frequency of the emitted light will change with the size of this semiconductor, so by adjusting the size of this nano semiconductor can control the color of the emitted light, because this nano semiconductor has the property of limiting electrons and electron holes, this property is similar to the atoms or molecules in nature, and therefore is called quantum dots.

The smaller the quantum dots are, the shorter the wavelengths can be generated, and the larger the quantum dots are, the longer the wavelengths can be generated; by exchanging the wavelengths of light emitted by blue LEDs, the desired wavelengths of light can be obtained; by absorbing short wavelengths of light, individual quantum dots radiate a narrow spectrum of light of relatively long wavelengths; by preparing and assembling quantum dots of the same size, luminous pink with high color purity and sharp spectra can be obtained, and color reproducibility can be achieved and improved, and power consumption reduced.

What is Quantum Dot Film？

Quantum dot film: The quantum dots are dispersed on resin material, dispersed and membranized, and encapsulated with 2 sheets of water vapor high barrier film to form a sandwich-like multilayer composite structure.

As the particle size of quantum dots is between 1 and 10 nm, the specific surface area is very large, resulting in oxygen and water vapor easily damage to the surface of quantum dots, resulting in a fluorescence burst. That is quantum dot technology currently facing the subject: anti-heat, anti-oxidation, waterproof. Therefore, it is necessary to use two layers of high-barrier film and special polymeric materials wrapped in quantum dots to solve these problems.

Anti-heat countermeasure: Adopt the film form and set the necessary distance from the LED light source of the heat generation source.

Anti-oxidation/water countermeasure: Adopt water vapor high barrier film for a wrap-around package.

Product Features

Quantum dot film as a new nano-material with unique light characteristics, can accurately and efficiently convert high-energy blue light into red and green light, quantum dots can form a thin film on the LED backlight of the LCD display, with blue LED irradiation can emit the full spectrum of light, through the fine adjustment of the backlight, can significantly improve the color gamut performance, so that the color is more vivid.

Quantum dot display technology has been comprehensively upgraded in various dimensions such as color gamut coverage, color control accuracy, red, green, and blue color purity, etc. It is regarded as the high point of global display technology, and also as a display technology revolution affecting the world. Compared with traditional LCD displays, the color gamut of quantum dot display can reach 110%.

Quantum dot film is a wide color gamut special optical film made of quantum dots, barrier resin, and optical grade hydroxide barrier film as the main raw materials, combined with high precision coating technology.

Product Benefits

The advantages of quantum dot film can be summarized as "high, pure, and stable" three major aspects.

"High" is the high color gamut, under the NTSC standard, the color gamut of ordinary LED TV is only 72%, the first generation of high color gamut TV is only 82%, the OLED display can reach 100%, while the color gamut coverage of quantum dot TV is up to 110%.

"pure" is the color pure, color purity than ordinary LED to improve more than 50%, accurate rendering of natural colors;

"Stable" is stable performance, long life of the film, stable inorganic nano-materials of quantum dots can ensure that the color is constant and does not fade, color lasting and stable up to 60,000 hours.

How Quantum Dot Film is made？

Quantum dot materials are sensitive to water vapor and oxygen due to their special properties, thus necessitating the use of high-barrier films for structural encapsulation. When coating, we must consider not only the control of the coating thickness but also the total thickness after laminating into a sandwich structure. The current quantum dot film coating thickness is generally around 50-100um, and this relatively large coating volume can be applied in several ways such as comma, roll coating, and slit.

A more ideal coating method is slit coating. Slit coating is the principle of its operation is to pump the fluid in a certain amount into a mold that can spread the fluid evenly. It is a closed system and secondly, it is pre-metering the coating material by means of a precision metering pump.

It is based on these two points that the slit coating method has some advantages that other coating methods do not have: more uniform coating weight and overall distribution; easy switching between thick and thin coating processes; minimized volatile emissions, coating contamination, raw material waste, and workplace mess.

Due to the high coating accuracy, the extrusion volume can be controlled by the power motor speed of the precision metering pump body, enabling a closed-loop loop. With constant system tension, the rotational speed of the slit coating head's glue feed motor is a function of quantum dot film thickness. The thickness of the quantum dot film is detected online in real time, and after relevant calculations, it is fed back to the glue-feeding motor of the slit coating head. By changing the speed of the glue-feeding motor, the thickness of the quantum dot film can be precisely controlled.