|LED display screen application and development|
LED display screen is a new type of flat panel display device that appeared in the 1990s. Due to its high brightness, clear picture and bright colors, it is unique in the public multimedia display field, so the market space is huge.
LED display market
Climbing as technology advances
The development of LED display can be divided into the following stages: the first stage is from 1990 to 1995, mainly monochrome and 16-level two-color graphic screen. It is used to display text and simple pictures, and is mainly used in public places such as stations, financial securities, banks, post offices, etc. as a public information display tool.
The second stage was from 1995 to 1999, with a 64-level, 256-level grayscale dual-primary video screen. Applications such as video control technology, image processing technology, and fiber-optic communication technology have taken LED displays to a new level. The large-scale integrated circuit chip for LED display control was also developed and applied by domestic enterprises at this time.
In the third stage, since 1999, red, pure green and pure blue LED tubes have flooded into China. At the same time, domestic enterprises have carried out in-depth research and development work, and full-color displays produced using red, green and blue primary color LEDs have been widely used. A large number of public places such as sports venues, convention centers, and plazas have been introduced, bringing the domestic big screen into the full-color era.
With the rapid development of the LED raw material market, surface mount devices have been available since 2001, mainly used in indoor full color screens, and with high brightness, bright colors, low temperature characteristics, freely adjustable dot pitch, different price requirements According to the acceptance, in just over two years, the product sales have exceeded 300 million yuan, and the surface mount full-color LED display application market has entered the new century. In order to adapt to the "slimming" plan of the 2008 Olympic Games, Liard developed a surface mount dual-primary display, which is widely used in training halls and competition timing scoring systems. In terms of full-color screens in the Olympic venues, for the austerity investment, most of the full-color screens are detachable. They can be used as live broadcast tools during the Olympic Games. They can be used for rental after the event, as a public application tool for performances and national policy announcements. The method can recover the cost as soon as possible.
As far as the market is concerned, China's accession to the WTO and Beijing's successful bid for the Olympic Games have become a new opportunity for the development of the LED display industry. The domestic LED display market has continued to grow. Currently, in the domestic market, the domestic LED display market share is nearly 95%. The international market for LED displays is expected to grow at a rate of 30% per year.
At present, the main led panel manufacturers of LED display are concentrated in Japan, North America and other places, and the share of LED manufacturers in China is negligible. According to incomplete statistics, at least 150 manufacturers in the world currently produce full-color screens, of which about 30 are large-scale companies with complete products.
Domestic LED display
Where is the technology gap?
With the continuous expansion of the LED display market, the domestic full-color market is gradually divided into three grades. The first gear is the high-end products produced by internationally renowned companies such as Barco and Panasonic; the second gear is the products produced by domestic large-scale enterprises using Nichia high-quality LEDs; the third gear is the display screens made by LEDs produced in China. These three grades of LED display also have a big difference in price and function.
In terms of technology, the development of LED display screens must closely follow the quality characteristics of world-class enterprises. At present, the domestic high-quality LED display screens and foreign top products have little difference in image processing technology and front-end video processing technology. The main gap lies in the following Two aspects:
Single point color confirmation
The “single point color confirmation” technology ensures a realistic color display that lasts for years.
At present, the domestic products can only adjust the unit module and the unit box, and can not achieve true single point adjustment, so there is a difference in color and brightness consistency, especially after the display unit is replaced by maintenance, due to the LED The parameters may change, the display effect is difficult to keep consistent with the original screen, and this work is done by dedicated large-scale equipment in foreign countries, and there is no such equipment developed in China due to product characteristics, and also hopes that the society-related industry And equipment manufacturers can pay attention.
This work is currently done in Bacolyd: in the module, the LED tubes in each pixel have their own color and brightness values. These LEDs must be accurately measured at the factory installation. Once, these data are simultaneously stored in the EEPROM in each module, and when the display signal is processed, the digital processing device (DIGITIZER) will read the information from each EEPROM and correct the brightness and color difference of the LED. To ensure that the display is in a consistently optimal state.
At present, the casings of domestic products are basically processed by single-piece sheet metal. The processing technology is poor, the precision is not high, the appearance is not beautiful, and the waterproofness is not very good. Especially in the harsh outdoor environment, the system is unstable. .
The cabinets adapt to harsh working conditions, and the external hardware of all cabinets is housed in an aluminum alloy casting box with IP65 standards. The special sealing measures used in the cabinet are sufficient to prevent the entry of rain and dust. The number "5" is a level to prevent liquid infiltration, and is also one of the design requirements, so that the display system can work normally in rainy or water-free environments.