Liu Cixin, a famous Chinese science fiction writer, mentioned his daughter's home after 200 years : "In this hyper-information age, all objects can be turned into a display screen, including the four walls of your home. You can make the walls disappear at any time and place yourself in any scene." , which in “The letter to my daughter: the World after 200 Years (Preface of the book ,the Wandering Earth)” .

    The book, published in 2016, depicts the world 200 years later, in 2216.  As a display practitioner, I think this scenario is not far away from becoming a reality. And there is already a related technology as a preliminary form of this scenario: the transparent display.

    A transparent display is a kind of screen that looks like glass, which can be transparent and display videos, pictures and other information .

    According to the technical solution, the transparent display can be divided into liquid crystal transparent display, OLED transparent display, LED transparent display, holographic projection display, MICRO LED transparent display, PDP transparent display, etc.  Some types are gradually out of the mainstream market with the decline of their technology, such as PDP transparent display;  Some types are difficult to be applied on a large scale due to high cost and excessive restrictions, such as holographic display;  And some types also need a significant improvement in technology to enter the practical, such as MICRO LED transparent display.  Now the mainstream market is mainly LCD transparent display, OLED transparent display and LED transparent display.

    Generally, there are two methods to achieve liquid crystal transparent display. The first is to remove the backlight, and use the external light as the light source to achieve the transparent effect. The second is to place the backlight on the side of the display. The former is suitable for large sizes and the latter for small sizes.

    Since the OLED screen emits light actively, so when the TFT substrate and electrode materials are made of transparent materials, the light transmittance of the device can reach more than 85% at ON state, and the light can be observed from both sides at OFF state.

    Transparent LED display is the micro-innovation of LED industry to the light bar screen. The SMT process, lamp packaging, control system are targeted improvement. Coupled with the hollow structure, permeability is greatly improved. LED transparent display is the only kind that can be arbitrarily large , not subject to size area in all transparent display technology.  The pictures appears to be suspended above the glass wall when the viewer stands at the suitable distance.

    In recent years, transparent display technology has developed rapidly. From transparent mobile phone screen, transparent window display, transparent TV, transparent display car glass, transparent display refrigerator, all kinds of products emerge in endlessly in various application scenarios, to bring people cool visual experience and deep impression. So its future development is full of imagination.

    The indoor walls made of transparent display basically realized the function of the book, which can be transparent and display any picture. Of course, a wall also need to have insulation, load-bearing and other functions, so this is just a prototype. We believe that as technology changes and industries cross over, the scenarios in the book are not far off.