Display technologies such as OLED/LCD/LED/Micro LED can achieve transparency
Aug 03, 2021
This year, Xiaomi launched a transparent OLED TV with a price of 50,000 yuan, which has earned gimmicks and a high degree of attention, and also brought transparent display into the public's field of vision. Compared to TV screens, the industry generally believes that commercial scenes that pursue beauty, technology, space, and budget are more suitable for transparent display.
Scrambled transparent display
In recent years, OLED has become a popular display technology in the global TV field. With the joint promotion and operation of many color TV brands, it has gradually gained a foothold in the high-end TV field.
According to data from the research organization Omdia, in the global TV product market of more than US$1,500, OLED products will account for 31.5%.
Wu Zhanghao, vice president of LG Display’s TV business unit, said: “LG Display’s transparent OLED screen demonstrates the infinite possibilities of OLED, and its differentiated experience will accelerate the global commercialization of transparent OLED.”
Industry experts believe that OLED’s Internet celebrity attributes have its own traffic, and OLED’s every move in the commercial field is also attracting attention, especially the technologically-sense transparent OLED display.
Earlier, the application of transparent OLED screens to the windows of Beijing Metro Line 6 and Shenzhen Metro Line 10 attracted the attention of industry, society and ordinary consumers. The screen can display real-time information, such as weather forecasts and news, train operation and train location, etc. It can be described as a walking billboard. Also with the help of transparent OLED to climb the hot search list is Xiaomi TV. After launching a transparent TV priced at 50,000 yuan, Xiaomi has earned enough attention. However, how long the OLED transparent display can stay on the home track is always a question mark.
Recently, LG Display signed an agreement with Panasonic to become its supplier of transparent OLED panels. Subsequently, Panasonic released two transparent OLED displays, using retail stores, museums and commercial lounges as potential application scenarios. Since then, LG announced that it has cooperated with a Swedish manufacturer to develop an automatic sliding door with a built-in transparent OLED display. Some people in the industry pointed out that the commercial scene is the application field of transparent OLED at this stage. LG Display has stated that transparent OLED displays have broad application scenarios, such as display windows and office spaces in shopping malls.
Industry experts believe that commercial scenes emphasize a sense of science and technology and a sense of space, which is an area where transparent display can flex its muscles. In an interview with a reporter from China Electronics News, Dr. Ma Beibei of CCID Think Tank Institute of Integrated Circuits said that the display in commercial scenes has relatively simple display content and has relatively loose requirements for display performance.
Transparent display technology "competes for beauty"
Although transparent display has received more attention due to OLED, it is not only OLED that can achieve transparent display, but LCD, LED, Micro LED, etc. can all achieve a certain degree of transparent display. At present, LCD and LED transparent display products have been applied on a large scale in the commercial display field, and the degree of industrialization is much higher than that of OLED transparent display.
Liu Huilian, chief analyst of Omdia, said in an interview with a reporter from "China Electronics News" that LCD adopts special liquid crystal materials and abandons CF and polarizers, which can also greatly increase light transmittance and achieve transparent display. At present, this technology is mostly used in commodity display cabinet screens, refrigerated cabinet screens, fish tank screens, unmanned vending machine screens, etc., and the price is high.
LED transparent screen is currently the most widely used transparent display product on the market. It has the characteristics of ultra-wide viewing angle, ultra-light and ultra-thin, high perspective rate (up to 80% to 95%), and low price. LED transparent display products can be divided into PCB hollow LED screens, LED ice screens, LED crystal film screens, etc., and have been widely used in window beautification, giant interior decoration, and large-screen displays. Among them, the LED crystal film screen is favored by the industry due to its flexibility and foldability.
It is reported that the crystal film screen adopts LED lamp bead bare crystal ball planting technology, the light board adopts transparent crystal film film, and the surface is etched with a transparent mesh circuit. After the components are pasted on the surface, the vacuum sealing process is adopted, which can be bent, cut, and can be directly pasted. On the glass curtain wall, the original structure of the building is not destroyed. The screen is invisible when not playing, and does not affect indoor lighting.
So, which transparent display technology is the perfect partner for commercial display?
In Liu Huilian's view, from the perspective of light transmittance, LED direct light-emitting transparent screens have the highest light transmittance, followed by OLED products, which have a light transmittance of about 40%. Since LCD is passively emitting light, it needs a backlight in any case, so the so-called transparency of LCD is not really transparent, but only through technical means to increase the light transmittance. From a cost perspective, OLED currently has the highest cost, followed by LCD. However, because the cost of LED direct-emitting transparent screens is related to many factors, including dot pitch, cabinets, lamp beads, PCB boards, power supplies, etc., the cost of high-PPI LED products may exceed LCD or even OLED.
Technical difficulties need to be broken
Speaking of why more and more transparent display products are used in commercial scenes, some experts believe that shopping malls, hotels and other places are pursuing a sense of space and aesthetics, and transparent display products can undoubtedly meet the above needs at the same time.
Liu Huilian believes that the market is increasingly pursuing standardized and modular building material-based displays. In the future, commercial display products may become an indispensable part of building modules, just like glass. However, at this stage, there are still many difficulties in various transparent display technologies that need to be broken, and the adaptability to commercial scenarios needs to be further improved.
The balance between transparency and resolution is the biggest difficulty faced by transparent OLED panels. If the screen resolution is increased, the light transmittance will also decrease.
In an interview with the reporter of "China Electronics News", Chen Hui, general manager of Ovi Revo, pointed out: "How to improve the resolution and transparency at the same time on the technical level is the key to the popularization of transparent OLED products to the general public."
Ma Beibei pointed out that as an active light-emitting technology, OLED does not require a backlight system and has a higher aperture ratio. It is suitable for making high-transmittance transparent screens. However, in the process of making the whole machine, a high degree of cooperation with other systems and components is required.
Like OLED transparent display products, LED transparent display also has technical problems.
Liu Tun, a senior analyst at CCID Consulting, told the reporter of "China Electronics News" that because of the large LED lamp beads in the commercial field, the resolution of LED transparent display products is low, which affects the image presentation effect. However, this type of display screen is generally placed in a shopping mall or a place with a larger space, and does not require high resolution. However, LED still has a long way to go if it wants to meet the requirements of fine commercial display. In Liu Tun's view, from the perspective of technical principles, Micro LEDs can also be made into transparent display products. If technical breakthroughs are achieved in the future, the resolution and display effects of transparent display products can be further improved.
