Turning the display screen into the same transparency as glass, a scene that sounds like it would only be realized in a science fiction movie, has now gradually fallen into reality.
Xiaomi’s transparent TV illustrates this possibility: it can display all kinds of video content, but also like a glass cabinet, allowing you to see the wall and decorations on the back of the TV through the screen.
How is that achieved?
The shape of the TV is relatively fixed, like a "black box", with many parts hidden inside. Therefore, the idea of making the TV transparent is simply "remove all that is not necessary, and what is left must be transparent", which also runs through the birth of Xiaomi's transparent TV.
The first is the back panel of the TV. The back panel is almost all black, and there are various components hidden inside: T-CON board, power supply board, main board, etc... These are all non-essential items that prevent the TV from becoming transparent.
But "removing" does not mean "throwing away". What needs to be done is to take these components out of the back panel and reintegrate them into an external host, and then establish a connection with the screen through a cable to make it work normally.
This kind of processing scheme has actually been partially adopted on the Mi Mural TV, that is, the heavy and redundant "burden" on the TV back panel is removed, and the host part of the original back panel is externally installed, thus realizing the extremely thin and light screen. The external solution provides a prerequisite for the transparency of the TV. The plan of Xiaomi Transparent TV to separate the host and the screen is similar to this, but more complicated.
After eliminating redundant physical components, you can now focus on the screen itself. At present, the screen display schemes widely used in TVs are LCD (liquid crystal) and OLED. Both of them can be made transparent, but OLED is because of its nature. Luminous characteristics, has the inherent advantages of making transparent TV.
To know that OLED is better than LCD, we need to revisit a knowledge point, that is, the "self-luminous" characteristic of the OLED screen itself, which means that each red, green or blue sub-pixel on the screen will emit light by itself without relying on additional The backlight.
Only in this way, OLED screens can omit the common liquid crystal layer, backlight layer and other modules in traditional LCD screens, achieve higher color contrast, and ensure sufficient lightness and thinness in form.
This innate structural feature also meets the needs of many manufacturers who want to make the display screen thinner, or even bend and fold.
But for transparent TV, the real difficulty is to make these millions of tiny pixels "transparent enough." Of course, we can take it for granted that as long as we choose a substrate with a higher light transmittance, and replace the upper and lower cover plates, and the positive and negative electrodes with glass, we can easily let light pass through the panel, making it the same as glass.
But now, panel manufacturers have also thought of a more tricky approach, that is, to introduce the concept of "transparent pixels."
The introduction of transparent sub-pixels is what makes the TV transparent. LG transparent OLED screen-it adds a new "transparent sub-pixel" based on the original four pixels of red, green, blue and white. This kind of pixel does not emit light, nor does it participate in image display, but it itself is made of highly transparent materials.
Finally, when countless such pixels are evenly distributed on the panel, the screen will naturally obtain a certain transparent effect, but at the same time it can also take into account the display of color images.
On this point, I personally like Xiaomi’s "blind" explanation. That is, a shutter with a pattern, if the leaves are completely closed, you can see the complete picture, but at the same time the scenery behind is completely blocked by the shutter.
But if you unscrew the blinds at an angle, you will find that although the picture on the blades is split, it does not affect the overall look and feel, and you can still clearly identify the pattern content on the blinds. Moreover, the unscrewed blinds make the outdoor scenery show through, and the picture and the scenery coexist.
By analogy, blinds and windows form a whole transparent screen. The display area is the "blade" of the blinds, and the transparent area is the "gap between the blades" after unscrewing.
Although the transparent area cannot display the image, if the "gap between the leaves" is properly controlled and made small enough that the human eye cannot detect it, the display area composed of each leaf can show a clear and complete pattern. And the "gap between the leaves" also reveals the scenery behind, achieving a visually magical transparent effect.
After understanding the principle of "blinds", we will analyze the principle from a microscopic point of view. In addition to the WRGB 4 sub-pixels in the conventional OLED screen, the pixels of the transparent OLED have also increased by nearly 50% of the area "transparent sub-pixels."
"transparent sub-pixel + WRGB sub-pixel" constitutes a single pixel of the transparent OLED screen, so the structure of the pixels on this 55-inch transparent screen has 1920X1080=2073600.
In summary, these enough WRGB sub-pixels form the "leaf" in the blind principle and are responsible for displaying images; in addition, enough transparent sub-pixels form the "gap between the blades" in the blind theory and are responsible for transparency.
Because nearly half of the total number of pixels is completely transparent as a whole, such a transparent area is large enough and evenly distributed, so extremely high transparency is achieved from the visual effect, and the other half of the display area composed of WRGB is also It has more than half the number of pixels to display the image, so the display level is also high.
But you may have noticed that under such a structure, the pixels that really allow light to pass through are actually only a part of the total.
This is why, at this stage, the transparency of transparent TVs is only about 30-40%, not 100%. After all, some sub-pixels are still used for image display, but as long as the density of transparent sub-pixels is high enough and the amount is large enough, it is enough. "Cheated" the user's visual senses.
Making the screen transparent only solves the first problem of transparent TV. After all, in addition to the screen, the back of the traditional TV also has power supplies, motherboards, audio and other devices, which can't disappear out of thin air.
From the perspective of technology itself, the transparent display is not a very black technology. In the early years, manufacturers including Samsung, LG, and Panasonic have shown many prototype solutions using transparent panels, and none of them are related to TV sets.
The transparent notebook displayed by Samsung at CES 2010. In 2010, Samsung launched a concept laptop equipped with a transparent OLED screen. You can see the Windows system running on the screen, and the clarity of icons and text is very good.
In 2012, Samsung also showed a prototype of a "smart window" that supports touch. You can imagine the feeling of sliding on a piece of transparent glass and tapping the interface, which is infinitely close to the scene in a science fiction movie. .
In fact, Samsung was the company that had the most hope to commercialize transparent OLED screens-it did get orders from several manufacturers in 2016, but shortly after shipment, Samsung temporarily decided to stop the production of transparent OLED screens. Instead, the focus is on the research and development of OLED screens for smart phones with more potential and more profit.
At present, the only supplier with mass production capacity of transparent OLED screens in the world is LGD. The panel used in this Xiaomi transparent TV is also provided by LG.
The "coolness" of transparent TV is also the main reason why it is so desirable. But in terms of practicability, TV sets may not be the most suitable category for transparent displays.
After all, when we watch TV, we do not simply look at that screen, but rather look at the pictures and image content displayed on the screen.
But in a transparent screen, the display subject becomes very messy. You will not only see the picture of the TV itself, but also through the screen, you will see the wall on the back of the TV, ornaments, etc., and even the light in the real world. , Will have a negative impact on the picture.
After experiencing the Xiaomi transparent TV, I know that only when the light is relatively dim or the background is a black wall environment, can you get a better viewing effect. Otherwise, the picture of transparent TV is not as clear as traditional TV.
If you are looking for practicality, perhaps what you need is a TV that can adjust the transparency, which can display video content normally like a traditional TV, and can become a transparent decoration when not in use, or Display simple information such as time and weather.
The transparent TV prototype designed in cooperation with the furniture brand Vitra can adjust the transparency. Such a product is not impossible. Last year, a transparent TV prototype displayed by Panasonic can switch back and forth between transparent and opaque states.
This OLED TV adds a similar polarizing layer, which is equivalent to making a layer of "blinds" for the TV. Only by controlling the opening and closing of the "blade" through the electric current to block the light from the back, the screen can no longer be transparent and return to the state of a traditional TV. But the disadvantage is to abandon the light and thin characteristics of the OLED screen itself.
In addition to TV sets, transparent display screens can also find many application scenarios. Such as outdoor billboards, or information display boards in companies and museums.
A dynamic advertising stand made of transparent OLED screen. The "Magic Screen" of Shenzhen Metro also has fields like public transportation and automobiles. For example, some netizens shot a video of the "Magic Window" system in the Shenzhen Metro. It not only retains the transparency of the glass itself, but also can be used in the glass. Information such as stations and route maps are displayed on the screen. This is actually the result of the transparent OLED screen. In fact, it is also useful on mobile phones, but it is not up, so it is not understood by many people.
