Splicing problem. LCD and PDP have splicing problem, DLP is slightly better, the projection fusion in the proper handling of the splicing area can be dealt with; small pitch LED display technology is completely no splicing.
Display effect. From the gray scale, contrast, brightness, refresh rate and other indicators, DLP rear projection and projection and fusion technology display effect is the worst (by the physical properties of the projection of the worst), LCD display effect is better, but after a long time of use, due to the brightness attenuation and the appearance of dark edges, black corners, in addition to the screen and the screen between the brightness and color differences, and the human eye on the difference of the thing is very sensitive;
LED display Technology grayscale, contrast, refresh rate and other indicators are very good, can also be easily solved through the point-by-point correction of light decay, but the biggest problem lies in 2 points: ① dead lights: outdoor LED display screen dead light rate of the standard is generally one in 10,000 to three out of 10,000, but the small pitch LED standards need to be significantly improved, take the P2.5 specifications of the small pitch LED display screen as an example, each square meter of **** there are 160,000 Lamp beads; if the pitch further to the level of 1 mm, there are 1 million lamp beads per square meter, at this time, if in accordance with the LCD screen "no more than 3 bad points" standard requirements, LED display is almost impossible to reduce the rate of dead lamps to three parts per million. ② brightness and grayscale contradiction: indoor and outdoor application of a most significant difference is the change of environmental light. LED display in outdoor applications, the intensity of sunlight during the day is very high, so the outdoor LED display needs to be bright, bright, bright! The higher the brightness of the display, the higher the technical specifications of the display. For indoor, because often need to watch the display for a long time, the brightness of the LED display should be greatly reduced, with reference to the brightness range of the household TV is 350 cd/㎡-500 cd/㎡; the brightness range of the DLP splicing wall is 250 cd/㎡-400 cd/㎡; and the brightness range of the LCD splicing wall is 450 cd/㎡-700 cd/㎡. LED as a self-luminous LED as a self-luminous display technology, and passive light-emitting different, the human eye is more sensitive, so you need a lower brightness human eyes will be comfortable. LED display needs to be lower than 300 cd / square meter or so, to be able to achieve the best viewing effect of the human eye (internationally recognized standard is that more than 700 cd / square meter brightness viewing will be detrimental to the health of the human eye, in addition, some of the special application areas on the "Low brightness and high gray" requirements are more demanding, such as television studios sometimes even require the display brightness within 100cd / square meter), look at the current market specifications of the small pitch LED display, it is not difficult to find the existing display brightness and the actual application of brightness there is a big gap. To a production of small pitch LED products listed companies in Beijing, for example, the company's official website clearly indicates the specifications of LED small pitch products, the brightness value is greater than 1200cd / ㎡, much higher than the comfort zone. Professional test experts in the industry on a number of manufacturers of small spacing LED display screen for a large number of practical tests found: when the display brightness reduced to 500 cd / ㎡ or even from 600 cd / ㎡ down, the screen has begun to appear a more obvious phenomenon of gray-scale loss. And with the further reduction of brightness, gray loss is also more and more serious. When the brightness is reduced to 200 cd / m2 below, most of the display of gray-scale loss is very great, the picture quality is almost to the degree of "unbearable". Therefore, how to achieve the minimum loss of grayscale under the brightness level of 300 cd / square meter, for the LED display application enterprise is a threshold, which is also the moat of the excellent enterprise.
Resolution: DLP, LCD has a high resolution, 60 inches of a single display unit resolution can reach 2K HD, and small pitch LED display technology due to the pixel is composed of lamp beads, so under the premise of cost control, the resolution is lower than the other technologies. For example, the display and the signal source resolution matching problem, used in advertising and other areas of outdoor LED display screen does not need to have a standard resolution, customers only care about the display effect and brightness. Small pitch LED display into indoor applications, downstream applications rapidly expanding, such as command, control, monitoring and other fields, often need to display to match the standard resolution of the various subsystems output signals, such as high-definition camera 1,920 × 1,080 signals and so on. The standard LED display box may not be able to match the required standard resolution within the specified dimensions.
Cost. In all indoor large screen display solutions, the lowest cost LCD splicing and projection and fusion (because the lowest cost LCD splicing wall in the indoor display field accounted for the largest share), followed by PDP splicing. Currently small-pitch LED display and DLP rear projection splicing compared to, it is difficult to say which one is higher or lower, because of the different point-spacing specifications of the small-pitch LED display, the cost difference is large, the current P1.9 display per square meter price and DLP rear projection splicing is comparable to the difference in gross margins, the cost of even higher than the DLP splicing products. For the affordable first industry users, under the premise of meeting the application requirements, consider the comprehensive cost-effective, small pitch LED may not become the first choice. Has been high cost is the main problem plaguing the small pitch LED, although the small pitch LED has many advantages. However, with the continuous investment in the market, the rapid improvement of small pitch LED technology, the cost of technology has been significantly reduced. The current commercial cost of products below P1.2 is too high, and users still can't afford it. This also means that the current LED process technology has not been a major innovation, and then small pitch, simply can not be popularized and promoted.
Life. From the point of view of the length of time, pure LED display technology has the longest service life, because indoor applications, LED display brightness requirements are very low, up to 20% of the maximum output power to meet the requirements.