The advantages and disadvantages of small spacing led display screen compared with traditional ld edisplay screen

- Jun 04, 2019-

1. Patchwork problem. Both LCD and PDP have the problem of stitching. DLP is better, and the splicing area can be disposed of when the projection fusion is properly handled. Small spacing LED display technology has no patchwork.


2. Display effect. From the gray level and contrast, brightness and refresh rate index, DLP rear projection and projection and the effect of fusion technology shows the worst (determined by the physical properties of projection the worst), LCD display effect is good, but after using for a long time, because of the brightness attenuation and appear dark side, black Angle, also can appear between the screen and screen brightness and color difference, and the human eye is sensitive to different things; LED display technology has good gray scale, contrast, refresh rate and other indicators, and can easily solve the problem of light decay through point-by-point correction, but the biggest problem is 2 points:


(1) dead light: outdoor LED display screen dead light rate standard is generally 1/10000 to 3/10000, but the small spacing LED standard needs to be significantly improved, take P2.5 specification of small spacing LED display screen for example, its per square meter total 160,000 lamp beads; If the gap is further reduced to 1mm, and there are 1 million beads per square meter, the LED display will hardly be able to reduce the dead light rate to 3 parts per million if the LCD standard is "no more than 3 bad points".


(2) the contradiction of brightness and grayscale: one of the most significant differences between indoor and outdoor applications is the change of ambient light. LED display screen in outdoor application, the intensity of daylight sunlight is very high, so, outdoor LED display screen needs bright, bright, bright! The brighter the display, the higher the technical specifications. For indoor use, the brightness of LED display screen should be significantly reduced due to the frequent need to watch the display screen for a long time. The brightness range of reference home TV is 350 CD/SQM -500 CD/SQM. The brightness range of DLP splicing wall is 250 CD /㎡-400 CD /㎡; The luminance range of the LCD Mosaic wall is 450 CD /㎡-700 CD /㎡. As a self-luminous display technology, LED is different from passive luminescence. Human eyes are more sensitive, so human eyes need lower brightness to be comfortable.


LED display needs to be less than 300 CD/square metre, can achieve the human eye is the best viewing (internationally recognized standards are, more than 700 CD/m2 brightness watch will cause harm to human health, in addition, some special application fields for more demanding high "low light grey", such as a television studio and sometimes require display brightness within 100 CD/m2), through small spacing on the market at present LED display specification, it is not difficult to find that the existing display luminance brightness there is a big gap with the practical application. Take a listed company in Beijing that produces LED products with small spacing as an example. The company's official website clearly indicates the specifications of LED products with small spacing, and the brightness value is greater than 1200cd/ m2, far higher than the comfort zone. Professional testing experts in the industry have carried out a large number of practical tests on the small spacing LED displays of several manufacturers and found that: when the brightness of the display is reduced to 500 CD/m2 or even from 600 CD/m2 downward, the picture has begun to appear a relatively obvious gray level loss phenomenon. And with the further decrease of brightness, the gray loss is more and more serious. When the brightness drops below 200 CD/m2, most of the screens lose a lot of grayscale and the picture quality is almost unreadable. Therefore, how to achieve the minimum loss of grayscale at the brightness level of 300cd/ m2 is a threshold for LED display application enterprises, which is also the moat of excellent enterprises.


3. Resolution. DLP and LCD both have high resolution, and the resolution of a single 60-inch display unit can reach 2K hd. However, the resolution of small-spacing LED display technology is lower than other technologies on the premise that the cost is controllable because the pixels are composed of lamp beads. For example, the resolution matching problem between the display screen and the signal source. Outdoor LED display screen used in advertising and other fields does not need to have standard resolution, and the customer only CARES about the display effect and brightness. After the introduction of small-spacing LED display into indoor application, the downstream application field expands rapidly. In fields such as command, control and monitoring, the display screen is often required to match the standard resolution signal output by each subsystem, such as 1,920× of hd camera. 1,080 signals, etc. Within the specified size, the standard LED display box may not be able to piece together the required standard resolution.


4. Cost. Among all indoor large-screen display solutions, the lowest cost is LCD splicing and projection and fusion (because the lowest cost LCD splicing wall occupies the largest share in the indoor display field), followed by PDP splicing. At present, compared with DLP rear projection splicing, small-spacing LED display is difficult to say which is higher and which is lower. Due to the small-spacing LED display with different gap specifications, the cost varies greatly. At present, the display price per square meter of P1.9 is comparable with DLP rear projection splicing, but considering the gross margin difference, the cost is even higher than DLP splicing product. For the industry users with the highest value for money, on the premise of meeting the application requirements, considering the comprehensive cost performance, small spacing LED may not become the first choice. High cost has long been a major problem with small spacing leds, which have many advantages. However, with the continuous input of the market, the rapid improvement of small-spacing LED technology, the cost of technology has been greatly reduced. Currently, the commercial cost of products under P1.2 is too high for users. This means that the current LED technology does not have a big innovation, no matter how small the spacing, it cannot be popularized.


5. Service life. In terms of service time alone, pure LED display technology has the longest service life, because in indoor applications, LED display brightness requirements are very low, the maximum output power of 20% can meet the requirements.