Small-pitch screens are mainly used in commercial fields, such as company meeting rooms, chairman's office, network video conferences, and information display needs of schools and educational institutions. Although the small-pitch LED attracts users with its advantages of high brightness, no seams, lightness and flexibility, and less installation space, there are still some irreconcilable contradictions in the small-pitch LED display, which will be serious if it cannot be properly resolved. Affect the experience of using the LED display.
Brightness reduction and gray-scale loss:
One of the most significant differences in indoor and outdoor display applications is the change in ambient light. When light-emitting diodes are used outdoors, the intensity of sunlight during the day is very high. Therefore, when light-emitting diodes are used outdoors, they need to have brightness and brightness! In fact, outdoors, the brightness of the LED display must reach 4000cd/m2 (luminous brightness per unit area), while indoors, the brightness of the full-color LED display must reach 800cd/m2 (Candra/m2) to ensure the normal operation of the display. , But at the same time, studies have shown that the sensitivity of the human eye to direct light sources is between 120cd/m2 and 150cd/m2, which is a compromise between health and visual effects, and LEDs are used as a self-luminous display Unlike passive lighting technology, human eyes are more sensitive to direct light sources, so human eyes need lower brightness to be comfortable.
Therefore, when the LED display enters the room, its brightness needs to be appropriately reduced to meet the needs of indoor display; but when the brightness of the LED display drops to 500cd/㎡ or even lower, or even below 600cd/㎡, it has begun to appear more obvious The phenomenon of gray-scale loss, and along with the further decrease in brightness, the gray-scale loss becomes more and more serious (generally speaking, the higher the gray level, the richer the color displayed on the display screen, the more delicate and full the picture, the gray is the display color The decisive factor of the quantity, for the LED display industry, the high-gray-scale screen brings the beauty closer to the real color). And when the brightness drops below 200cd/㎡, most monitors lose a lot of grayscale, and the picture quality almost reaches the level of "eye-catching", and a lot of picture details are missing.
(The picture on the left shows that the details of the picture are seriously missing after the grayscale is lost)
Image quality improvement and dead pixels increase:
The screen of the LED display screen is composed of countless LED lamp beads, so the fineness of the screen depends on the dot pitch (or density) of the lamp beads. The more LED lamp beads per unit area, the finer the picture of the LED screen The higher the display, the richer the display of screen details. Based on this, the current LED display is moving in the direction of small-pitch, mini-LED display.
But at the same time, due to technical defects, LED display screens are prone to bead dead pixels. Generally, the dead light rate of outdoor LED displays is generally 1 in 10,000 to 3 in 10,000, but for small-pitch LEDs , The failure rate of three ten thousandths can hardly meet the needs of daily use. Taking the small-pitch LED display of P2.5 specification as an example, there are 160,000 lamp beads per square meter; if the spacing is increased to 1 mm, each There are 1 million lamp beads per square meter. At this time, if the standard of "no more than 3 dead pixels" is used, the number of broken lights on the small-pitch LED display is uncountable; At 1 mm, the viewing is extremely poor.
3. Close observation and severe fever:
For indoor display devices, especially products that are positioned as display platforms for small and medium-sized conference rooms, audiences generally watch and use the screen at close range. Taking a typical conference display scene as an example, the screen is about 1.5 minutes away from the conference host and attendees. -5m.
However, the luminous efficiency of the LED display is very low. Studies have shown that the LED display is only 100W/W in the energy conversion process, and the electro-optical conversion efficiency is only about 20-30%, that is, only 20-30% of the input power Converted into light energy, the remaining 70~80% of the energy is all consumed by thermal radiation; in contrast, the incandescent lamps commonly used in the past can almost convert all the input electrical energy into light energy. Therefore, the LED display The heating of the screen is very serious.
Due to the long-term heating problem of the LED screen, its heat dissipation will cause the entire ambient temperature to rise (despite the cooling equipment such as air conditioners, the radiation generated by the long-term work of the screen still affects the surrounding environment is still uncomfortable), for those attending the conference If the meeting lasts for 1-2 hours or more, the place close to a heating screen will feel scorched, even if it is sitting relatively far away, after a meeting, even if it is not like on a hot pot An ant sweats like an ant, and it is difficult to maintain a good attitude. Prolonged sultry heat can make people feel uncomfortable.
The above are the more prominent problems among the many problems of the small-pitch LED display. Obviously, these problems are obstacles that must be overcome to limit the use of the small-pitch LED display in the indoor application environment. Although it is undeniable, compared with the traditional LED Compared with the display screen, the small-pitch LED display is a relatively technologically advanced new LED display product, but so far, the application of the small-pitch LED display in an environment like an indoor meeting room is still a problem worthy of attention. .
