The charm of the transparent display is very prominent: the OLED display screen when in use, and the transparent glass when not in use. This feature makes transparent display quite potential in the commercial field, especially in the retail scene; even in the home color TV and emerging technology-based decoration markets, transparent display may become an epoch-making new technology.
However, the realization of transparent display is not easy: liquid crystal display, projection display, OLED display and large LED screen are all developing their own transparent technology routes.
Recently, a Korean manufacturer, Changsung Sheet, has installed a thin-film transparent LED display on the glass surface next to the Fujitec escalator in an Indian shopping mall. As an advanced case of thin-film LED transparent display, the deployment and application of the display have been completed without destroying any existing original design, and its market excellence is evident.
The market casts a veto, only one short board is needed
Each transparent display technology solution has its own many advantages – however, when it comes to marketization, as long as there is a clear short board, it may seriously limit the ‘real implementation’ of this technology, or even allow a Technical solution failed! Industry experts pointed out that a truly marketable transparent display technology must have no “too prominent shortcomings”.
From this point of view, the liquid crystal transparent display system was first excluded from the market. Because liquid crystal imaging relies on “backlight illumination”. Then there are two main ideas for transparent liquid crystal display: the first is to use a fully transparent direct-lit backlight product – this is obviously difficult to provide a good and feasible solution with the existing technology, unless the backlight itself is an “ice screen” Such a transparent LED screen is obviously not in line with the principle of economy; the second is the use of side frame backlight technology, the backlight does not occupy the display area space – this technology is easy to achieve.
However, the transparent LCD display of the side backlight scheme naturally has: 1. The overall picture brightness is relatively limited, and it is more difficult to improve the brightness, which obviously conflicts with the high-brightness demand of the commercial display market; 2. The side backlight The source makes the side thickness of the display relatively large, which seriously affects the look and feel of the picture quality in the multi-screen splicing picture.
Compared with the backlight problem of liquid crystal display, OLED display seems to have no “concerns” naturally. As a direct light-emitting technology, OLED display not only can be made transparent of substrates and circuits, but even its OLED materials can be made transparent. From a certain point of view, this is an ideal “transparent display technology route”.
However, most of the current commercial transparent display requirements require a relatively large display area, which makes the RGB three-primary color OLED display technology unable to meet the market demand temporarily. At the same time, for large-size OLED products using white light + color filter film technology, the color filter film system seriously hinders the realization of the effect of transparent display.
On the other hand, OLED display is the same as liquid crystal display. When faced with the high-brightness demand of commercial scenes, the brightness is insufficient. In fact, the brightness of OLED display on color TVs is not as good as that of liquid crystal display. When it comes to transparent display scenes, the brightness is obviously only lower. Insufficient brightness limits the development of OLED transparent displays in the commercial display market.
Brightness sufficiency is a big issue! “This point also troubles projection transparent display products. Projection transparent display technology itself is very similar to rear projection technology, and the main change is the specific transparent display screen. It can be said that the technical path to realize transparent display” is a new upgrade and development part “The simplest, with the “best cost experience” under the existing technology route.
However, like liquid crystal and OLED transparent displays, projection transparent displays are also slightly inferior in brightness: by using higher brightness projection hosts, this can be completely overcome, but the price increase of high-brightness projection hosts is “very scary”. On the other hand, OLED and liquid crystal transparent display can be made into a thin piece, and projection requires a host product, which limits its “applicability of application deployment” in many places.
Liquid crystal, OLED and projection, in the transparent display, a common technical shortcoming is “brightness”. And this is exactly the advantage of LED large screen display. ——In fact, LED transparent display has become the “main force” of the commercial transparent display market.
Two kinds of LED transparent display, continuous technical iteration
At present, the main application scenarios of transparent display are commercial advertisements, stage performances and other places. These scenarios have high requirements on the brightness performance of transparent displays. The biggest advantage of LED display technology is “good brightness”: whether it is a traditional large LED screen, mini-led or micro-led, all of them are “excellent” with their brightness advantages.
However, the transparent development of LED large screens is not without bottlenecks: according to the characteristics of the bottlenecks, LED transparent displays can be divided into two types.
The first is the so-called ice screen, which relies on the curtain technology of “large pixel spacing” to achieve transparent display. The essence of the ice screen transmittance reaching 85% is that through the side-type LED packaging and integrated structure, the LED light-emitting and driving lines occupy less than 15% of the screen area. The remaining 85% is the transparent range.
This structure determines this transparent LED large screen technology, which can maintain an advantage in brightness, but in terms of PPI resolution, the index is relatively low – of course, it is applied to a longer distance, such as tens of meters, or 5 meters Viewing in the above large space, the effect is still guaranteed. At the same time, this integrated technology relies on the traditional LED pixel lamp bead structure, and the “thickness” index of its products is relatively large, which is less effective in realizing thin-film applications such as projection transparent display and OLED transparent display.
The second LED transparent display is to take full advantage of the most advanced semiconductor technology, such as TFT substrate technology used in liquid crystal and OLED displays; and mini-led or micro-led ultra-micro lamp bead technology; and through standard mass transfer technology to achieve product integration and packaging. In theory, the geometric “shape” effect of such a product is no worse than that of OLED transparent display, and the display brightness is higher: higher PPI resolution can also be achieved under the same brightness.
The film-like transparent LED display screen of Changsung Sheet Company, which has been widely concerned by the media this time, is the result of adopting many new technologies. In fact, the combination of mass transfer, TFT substrate technology, mini-led or micro-led ultra-micro lamp bead technology can basically achieve high pixel density transparent LED display at any size – this technology is similar to ice screen products. , each electrical characteristic index is reduced by one or even several orders of magnitude.
There are new technologies that can be adopted, and their technologies are still on the road of rapid upgrading, which is also the biggest feature and advantage of LED transparent displays.” The room for breakthrough is limited; OLED transparent display, at present, mainly uses sacrifice resolution, that is, further reducing the brightness of the unit screen as the main path of transparency. The future prospect of this solution is not clear.
However, one uncertainty of OLED transparent display technology is that OLED material technology is still progressing on a large scale. It remains to be seen whether there will be better OLED materials or more advanced QLED materials in the future to achieve transparent display in other ways.
In contrast, the integration process of LED screen, substrate technology, luminous efficiency of LED crystal particles, and miniaturization technology are still developing rapidly. This is another reason why LED transparent displays are considered promising. ——At the same time, the curtain-type LED transparent screen also has the special competitive advantage of “almost very low cost”, which is conducive to the popularization of products.
Transparency shows great commercial significance, and the two technologies may coexist in the future
In commercial scenarios, there are too many blank spaces and transparent glass that can be transformed into transparent display carriers: industry insiders pointed out that transparent display, as a multi-functional and differential display technology, is becoming a new choice for many “showcases”.
Among them, LED transparent display is used in low-cost, low-resolution, high-brightness window applications; high-performance stage type, high-brightness applications; and Changsung Sheet’s thin-film transparent LED display such as close-up viewing, higher resolution And in higher brightness application scenarios, coverage, popularization, or breakthroughs have been achieved.
In contrast, liquid crystal transparent display has basically withdrawn from the market competition sequence. OLED transparent display, because of unclear advantages and limited supply, only appears in very individual demonstration cases. Projection transparent display has unique advantages in holographic transparency and close-range, high-resolution demand scenarios.
In this regard, most industry analysts believe that LED transparent technology and projection transparent display technology have covered almost all possible “transparent display demand scenarios”. The two may be the “winners” in the future transparent display market, in which LED transparent display is the main body; projection transparent display can be used as a differentiated supplement.