Transparent display, let science fiction scene into reality

At present, the more common transparent screens are transparent LCD screen, transparent OLED screen and transparent LED screen.
Liquid crystal screen, also known as LCD screen, is a display device based on liquid crystal electro-optic effect and liquid crystal material as the basic component. The LCD screen is composed of a certain number of color or black-and-white pixels. The main principle is to stimulate the liquid crystal molecules through the current to generate points, lines and surfaces, and then cooperate with the back light source to illuminate, so as to form the picture. Therefore, the general LCD screen needs to be equipped with lighting equipment such as light source and reflector at the back, which does not meet the requirements of transparent screen.
However, for LCD display cabinets, such as the transparent screen vending machines mentioned above and some transparent screen windows, the situation is somewhat different. They cancel the light source and reflector on the back of the LCD screen, but use the rear box (i.e. exhibition container or container) as the backlight unit for lighting, that is, although these screens are indeed “transparent screens”, they are still inseparable from the rear light source. If the light of the box of the exhibition container is turned off, it will seriously affect the use effect.
Transparent OLED screen is the main force of transparent screen devices at present. OLED screen can drive the organic film to emit light through current, which has the characteristics of self luminescence. Each pixel of OLED screen can emit light by itself without relying on additional backlight.
The basic structure of OLED is a sandwich like structure composed of thin and transparent indium tin oxide (to) with semiconductor characteristics, which is connected with the power anode and another metal cathode. The whole structure layer includes hole transport layer (HTL), light emitting layer (EL) and electron transport layer (ETL). When the power is supplied to an appropriate voltage, the anode hole and cathode electrons will combine in the light-emitting layer to produce photons. According to different material properties, they can produce three primary colors: red, green and blue, which constitute the basic colors we see.
In addition, there are “transparent sub pixels” in the transparent OLED screen. This pixel itself does not emit light and does not participate in image display, but it is made of transparent materials. Therefore, the transparent OLED screen not only takes into account the display of color images, but also obtains a certain transparent effect. When the density of transparent sub-pixel is large enough to deceive people’s eyes, it is “transparent” in our view. Some transparent TVs use transparent OLED screens.
The principle of transparent LED screen is somewhat similar to that of transparent OLED screen. Both of them arrange the light-emitting units (light beads) on the transparent background to achieve the transparent effect. However, due to the size of LED light beads, the screen must be made larger to achieve better transparency

Therefore, most of the transparent LED screens we see are used in the window or large stage of the outer wall of the mall. It is difficult to see a small transparent LED screen.
The contradiction between transparency and privacy
In fact, some transparent screen products have appeared in our lives.
In 2009, Sony Ericsson launched the first transparent screen mobile phone Xperia pureness. Unfortunately, due to the technical level at that time, the screen transparency of this mobile phone is not very high, and it is still a black-and-white screen.
In 2011, Lenovo S800, the first color transparent screen mobile phone, came out. Compared with Xperia pureness, the transparency of S800 has been greatly improved. However, like Xperia pureness, it belongs to a functional machine, which is still a long way from the cool smart devices in the film.
In 2020, transparent screen devices made new progress, and Xiaomi launched transparent screen TV. Transparent screen TV has greatly improved the effect and transparency, but there are also some problems, such as the viewing effect cannot be guaranteed from the back, and the transmittance and resolution are not high.
At present, transparent screen technology is still developing. And the transparent screen that looks cool and full of sense of science and technology is also controversial.
On the one hand, the most important thing is that a completely transparent mobile phone is bound to have the problems of privacy and information leakage. If it becomes opaque when used, it deviates from the original intention of the transparent screen mobile phone.
On the other hand, a mature transparent device is not only transparent on the screen, but also needs to make the components such as battery, processor, camera, microphone and speaker transparent, which is still difficult at present. If complete transparency is achieved, the assembly, strength and surface wear resistance of mobile phones also need to be considered by manufacturers and users.


Post time: May-06-2022