Guide to Small Pitch LED Display

1. What Is Small Pitch LED Display?

Small pitch led display refers to indoor led display with led pixel spacing below P2.5, mainly including P2.5, P2.0, P1.8, P1.667, P1.56, P1.25 and other led display products, with the improvement of led display manufacturing technology, the resolution of traditional led display has been significantly improved.

Because of the small pixel pitch and high resolution per unit area, the small pitch led screen can display higher definition graphic images and videos and can also display more led hd video and image images, especially in the use of image splicing, which can be seamless and any large area splicing.

Small pitch led display is a complete system, including led display system, HD display control system and heat dissipation system, etc. Small pitch led display adopts pixel-level point control technology to achieve state control of the brightness, color reversibility and uniformity of the display pixel units. In the production process of the display all adopt automatic reflow soldering process, no manual post-soldering.

2. Advantages of Small Pitch Display:

 •  1). Technical Defects of DLP:

A. Previously, the indoor mid-to-high-end display market was dominated by DLP rear projection display, but there are technical defects, first, the 1mm spacing gap between display units that cannot be eliminated at all, which can swallow up at least one display pixel.

B. Secondly, it is also inferior to the direct light-emitting led display in terms of color expression.

C. The shortcoming is that the difference between DLP display units causes the uniformity of color and brightness of the whole display is very difficult to control, and as the running time of the product increases, the difference between units will also become larger and larger, and the spacing gap is difficult to keep consistent and will become more and more obvious.

D. The color difference between units and the adjustment of the spacing, even in the later maintenance and repair, is a relatively difficult thing. The biggest competitiveness of indoor high-density narrow pixel pitch led display is that the display is completely seamless, and the display color is natural and true.

E. At the same time, in the later maintenance, direct view led display already has a mature point-by-point correction technology, the use of more than one or two years of display can use the instrument for one-time correction of the whole screen, the operation process is simple, the effect is also very good.

 •  2). From many aspects of the evaluation of the two, it must be high-density fine pixel pitch led display is better than DLP rear projection and has the following advantages.

A. Seamless Splicing

Splicing large screen display technology in the maximum to meet customer demand has always been unable to avoid the impact of physical bezel, even ultra-narrow DID professional LCD screen, there is still an obvious splicing seam, only high resolution led display screen so that the splicing after the seamless requirements, high-density small pitch led seamless splicing advantage to highlight.

B. High Brightness Intelligent Adjustable

Led screen itself high brightness, to meet the strong light environment and dark light environment to the viewer comfortable viewing effect, to avoid visual fatigue, can be adjusted with the light sensor system for brightness.

C. High Gray Level for Better Color Performance

Even in low brightness display grayscale performance is almost perfect, its display screen hierarchy and vividness than the traditional display, but also can show more details of the image, no information loss.

D. High Refresh Frequency

The number of times the electron beam is repeatedly scanned on the image on the screen, the higher the number of scans, the higher the refresh rate, the better the stability of the displayed image (screen). The lower the refresh frequency, the more powerful the image flicker and jitter, the faster the eye fatigue. LED small pitch screen in high refresh, ingest screen stability, no ripple black screen, clear image edges, accurate restoration of the true information of the image.

E. Naturalized Color Reproduction

Adopting the international leading point-by-point correction technology, using the led luminescence principle, complete retention of color realism, avoiding other display technologies such as backlight projection of the material, light running path leading to color loss and deviation, to achieve the true sense of color reproduction.

F. Visual Experience In 3D Video

When customers choose to adopt 3D playback mode, the splicing wall will present shocking high-definition images, whether it is live TV, exhibition display, or digital advertising, are able to fully interpret the wonderful visual, so that the audience can enjoy an extraordinary visual experience.

3. Small Pitch LED Compared to Traditional Screen:

• 1). Spacing Problem

LCD and PDP both have the problem of splicing, DLP is slightly better, the projection fusion can handle the splicing area when handled properly; narrow pixel pitch technology has no splicing at all.

• 2). Display Effect

From the examination of grayscale, contrast, brightness, refresh rate and other indicators, DLP rear projection and projection and fusion technology display effect is the worst (decided by the physical properties of projection is the worst), LCD display effect is better, but after a long time use, due to brightness decay and dark edge, black corner, in addition to the screen and screen will appear between the brightness and color differences, and the human eye is sensitive to the differences.

LED backlight display technology grayscale, contrast, refresh rate and other indicators are very good, but also can easily solve the problem of light decay through point-by-point correction, but the biggest problem lies in 2 points.

A. Dead Light: the standard of high resolution outdoor led display dead light rate is generally one ten thousandth to three ten thousandths, but the standard of small pitch led needs to be significantly improved, take P2.5 specifications of small pixel pitch led display screen, for example, a total of 160,000 lamp beads per square meter; if the pitch is 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 If the standard requirement of “no more than 3 bad spots” is followed, it is almost impossible for the mini led display to reduce the dead light rate to three parts per million.

B. The contradiction of brightness and grayscale: indoor and outdoor applications one of the most significant differences is the change of ambient light. LED display in outdoor applications, the intensity of sunlight during the day is 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.

And for indoor, as often need to watch the display for a long time, the brightness of the led display should be significantly reduced, with reference to the brightness range of household TV sets is 350 cd/㎡-500 cd/㎡; the brightness range of DLP splicing wall is 250 cd/㎡-400 cd/㎡; the brightness range of LCD splicing wall is 450 cd/㎡-700 cd/㎡. LED as a self-luminous display technology, unlike passive light-emitting, the human eye is more sensitive, so it needs a lower brightness for the human eye to be comfortable.

LED display needs to be lower than about 300cd/m2 to achieve the best viewing effect on the human eye (the internationally accepted standard is that more than 700cd/m2 brightness viewing will cause harm to human eye health, in addition, some special applications for “low bright high gray” requirements are more demanding, such as television studios sometimes even require display brightness within 100cd/m2), looking at the current market specifications of 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.

Professional testing experts in the industry have conducted a large number of practical tests on a number of manufacturers of fine pitch direct view led video displays found that: when the display brightness is reduced to 500 cd/㎡ or even from 600 cd/㎡ down, the screen has begun to appear more obvious grayscale loss phenomenon. And with the further reduction of the brightness, gray loss is becoming more and more serious. And when the brightness is reduced to 200 cd/㎡ below, most of the display screen gray loss is extremely large, the picture quality is almost to the degree of “unbearable”. Therefore, how to achieve the minimum loss of grayscale at a brightness level of 300 cd/m2 is a threshold for led display application companies, which is also the moat of excellent enterprises.

• 3). Resolution

DLP, LCD have a high resolution, 60-inch single display unit resolution can reach 2K HD, while fine pixel pitch led display is lower than other technologies under the premise of cost control. For example, the resolution matching between the display and the signal source, outdoor led displays used in advertising and other fields do not need to have a standard resolution, customers are only concerned about the display effect and brightness.

After the small pitch led displays enter indoor applications, the downstream application areas are rapidly expanding, such as command, control, monitoring and other fields, often need to match the display to the standard resolution signal output from each subsystem, such as the 1,920×1,080 signal from HD cameras. And in the specified size, the standard led display case may not be able to splice the required standard resolution.

• 4). Cost Issues

Among all indoor large screen display solutions, the lowest cost is 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. At present, fine pitch led display and DLP back-projection splicing compared, it is difficult to say which is higher or lower, because of different point spacing specifications of fine pitch led video wall, the cost difference is large, the current P1.9 display price per square meter and DLP back-projection splicing equivalent, but consider the gross margin difference, the cost is even higher than the DLP splicing products.

For affordable industry users, under the premise of meeting the application requirements, consider the overall cost performance, small pitch led may not become the first choice. High cost has always been the main problem plagued by small pitch led, although 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 P1.25 is too high and still unaffordable for users. This also means that the current led process technology does not have a major innovation before, and then a small pitch, simply cannot be popularized.

• 5). Service Life

From the point of view of the length of use alone, 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.

4. Competition Between Display Methods:

• 1). Small Pitch LED VS DLP Splicing

Small pitch led screen has advantages in spacing, brightness, color saturation, resolution, and application flexibility, while DLP splicing wall has more advantages in picture delicacy and cost. These two technologies will form direct competition in the high-end indoor market.

• 2). Small Pitch LED VS LCD Splicing

Fine pitch direct view led video displays has significant advantages of seamlessness, longevity, and flexibility; but lcd splicing also has advantages in price and picture delicacy. However, affected by price and other factors, at this stage, small pitch led screens will mainly focus on the high-end market, while lcd splicing is mainly for the low-end market, so the competition between the two is not very prominent.

• 3). Small Pitch LED VS Projection Fusion

Small pitch led screen has advantages in color saturation, life span, post-maintenance, and demand for ancillary equipment, and does not have high requirements for the use of the environment; while the projection fusion system has higher brightness and certain price advantages, especially in the creative projection display has an irreplaceable position. Therefore, the two sides will not form a mutual replacement, small pitch led screen or will be in a specific range of applications to the projector fusion display challenges.

• 4). Small Pitch LED VS Large Size LCD

In comparison with the large-size LCD single screen, the so-called large-size LCD display products, the size range is limited to 70-110 inches, while the small-pitch led screen can cover from 70 inches to a theoretically unlimited size range, small-pitch led products have a broader size range, and the ability to meet market demand is also stronger. But in the LCD can be achieved within the display size, the LCD has a clear advantage in the degree of fine picture, while most products are more affordable. The competition between the two is significantly different and contradictory, not as a substitute for each other, but as a complementary cooperation in the face of different needs.

5. Small Pitch LED Display Applications:

With the continuous development and enhancement of led technology, indoor video wall display, especially small pitch products with its seamless splicing, low brightness and high gray, high refresh rate, ultra-high definition, low energy consumption, long life and many other characteristics to meet the market demand and energy-saving economic development advantages.

• 1). Television Audio

Before the emergence of led high-definition display, the more realized program is back-projection splicing or LCD splicing.

Traditional modular video wall display is difficult to meet the needs of such places in terms of technical parameters and performance, and the emergence of small-pitch products, directly overturned the studio’s understanding of led. Small pitch led video display screen in various technical indicators can easily meet the application of such scenes, and small led display because of no spelling, unit size is small, can easily meet the internal arc dance design, in contrast, color and other aspects is better than other video wall panels, so the broadcast application will be an important territory of hd led.

For the much-discussed more problem, in the led wall panel used in the field of broadcasting at the beginning, manufacturers and industry are trying to circumvent this optical problem through some technical means, but whether it is a soft film structure or hard screen structure, will improve the more effect at the same time cause the sharpness of the image quality is reduced. For the handling of moiré problem, we gradually agree more through the camera position adjustment, camera focal length of the joint adjustment and other means to minimize the moiré effect.

• 2). Smart City Construction

In the field of smart city construction, public safety, traffic, people’s livelihood, etc. have been closely related to the use of led display, which will also promote its high-speed development and popularization of the market. Small pitch led display as an alternative mainstream large screen display technology, will also play its inherent superior display advantages.

• 3). Enterprise Meeting Application

Thanks to the maturity of technology, in recent years, although the fine pitch direct view led displays price of video conferencing has been adjusted downward, however, for most enterprises, it is still a considerable investment, in line with the “good horse with a good saddle” design concept, the corresponding conference room supporting facilities should naturally be “high and mighty “Therefore, the video conferencing system display terminal in favor of small pitch led display, not only is the practical application needs of the inevitable, but also the enterprise through the hardware facilities to improve the image of the inevitable. It is also this pursuit of polarization, for high resolution led display provides an excellent opportunity to enter the conference room.

In large meeting places, the command and judgment scenes of multi-person meetings, shared video display is an indispensable hardware facility. Such scenes have higher illumination design or more transparent lighting design to meet the reading and writing needs of the people present. This higher illumination scene, the display brightness also put forward higher requirements at the same time, the display panel cannot be due to indoor lighting sources produce dazzling, reflections, and other interference.

Most of the fine pitch led display panels currently use matte black lights, plus the display surface is composed of rough pixels, so to meet the high brightness at the same time, and effectively overcome the impact of indoor lighting sources. At the same time, the seamless splicing advantage of led small pitch has been maximized in this application. Compared to rear projection and LCD (currently within 2mm of LCD narrow-edge splicing) the sense of gap, the user experience of led display is a level higher.

• 4). Public Security and Traffic Police

Display control system can access the electronic police system, 122 police system, GIS information system, GPS system, electronic monitoring system and all other business applications, synchronized call the scene key monitoring object information, data, images and other information, display the set range of public security, traffic police, fire and other police unit’s location and contact information, real-time on-site rescue observation and dispatch.

Connect the information center, network police detachment, technical investigation detachment and other business departments to realize the command center, command room, decision room and other sections of the collaborative display to help decision makers convene various departments, scientific deployment of resources, and the most rapid response to emergencies.

• 5). Military Application Fields

Advanced digital display technology, display unit seamless splicing technology, multi-screen image processing technology, signal switching technology, network technology and other scientific and technological means of application integrated into one, intuitive, real-time, all-round, fast to a variety of classes of information, image data, strategic orientation map and the scene of the situation real enlarged display, flexible to achieve military exercises, combat command, auxiliary decision-making, organization of troop training, Video conferencing, real-time monitoring and other complex functions in one, which greatly promotes the information visualization and intelligent construction of the military area and improves the efficiency and combat capability of the modern army. In recent years, small pitch led display technology has gradually matured and improved and is increasingly used in the construction of troops.

• 6). Security and Surveillance

With no splicing, good color performance, low energy consumption and other characteristics, small pitch led video panel can meet the high demand for picture quality of the scheduling command center, command and control center, studio, weather information center and other high-end indoor applications.

Compared with the DLP rear projection splicing screen, which is currently dominant in security monitoring, command and dispatch, and the fast-growing LCD splicing screen, the significant advantage of fine pitch led video wall is that there is no splicing, theoretically the size can be infinitely expanded, and the installation is flexible and diverse, the thickness of the screen body is thin, space-saving, high brightness, and can meet the needs of semi-outdoor environment.

In the early application of small pitch, in the field of security program design, especially small and medium-sized projects, we will feel helpless about the lack of resolution of the LED display, because the number of security signals, while the number of signals on the screen is also more, under the conditions of the display area constraints, the resolution is not enough, especially in the digital HD signal source backing, this hardware inequality phenomenon is particularly obvious.

Through the accumulation of experience in many projects, and familiarity with the security business model, LED + LCD hybrid mode, gradually accepted by customers. This model, to meet the customer’s multi-signal on-screen conditions, the introduction of LED as the main screen display, to avoid the technical defects such as LCD display screen spacing, but also a good response to security customers in the call for research and judgment signal to do zoom in on the demand for close-up.

Through the flexible configuration of the program, with different point spacing and LCD and other display technology integration, led display also cut into the security field of application, and with the increase in point density, there has been an opportunity to directly abandon the LCD in some projects, using the whole screen led display mode. Of course, with the progress of led technology, we will see more new display areas are explored.

• 7). Exhibition Display

Small pitch led display screen has a flexible formation mode, wide viewing angle, ultra-thin body, easy and fast installation and maintenance, and low power consumption, widely used in various public information display fields, such as hotel lobby, airport, cinema, hospital, and other information bulletin boards, as well as corporate image publicity, museum heritage display, sports stadium scoreboard, etc.

In the commercial field with public information display needs, small-pitch led display can replace the use of large and medium-sized commercial displays. Its significant advantage is that it can achieve a large size, low power consumption, long life, and can adapt to the use of long-time continuous power-on operation.

• 8). Business Education

LED small-pitch display can also meet the needs of various commercial fields of use, such as corporate meeting rooms, chairman’s office, network video conferencing, etc. It can replace the projector and create a bright office environment. Its rich electronic whiteboard supporting functions can also meet the information presentation needs of various schools and educational institutions.

Although the field of business and education is not the main direction of led small pitch screen, but compared with traditional projectors, electronic whiteboards, and other products, led small pitch screen is more convenient to install and maintain, especially its self-luminous characteristics, can meet the needs of bright conference rooms, classrooms, and other uses.

• 9). Home Field

The improvement of the fineness of the picture makes the indoor application of full wall led screen possible. The LED TV based on narrow pixel pitch led display technology, led small-pitch screen TV series, will also march into the family living room field. To the current dominant LCD TV, and projectors and other devices to challenge. Especially suitable for high-end home audio and video options such as villas.

As a household, the outstanding advantage of LED TV is the use of independent light-emitting technology, brightness, color, and refresh frequency have advantages over LCD TVs. Installation and maintenance and easier than the projector, and do not need to rely on the projection curtain, even in a bright audio-visual room can be displayed normally.

However, the current small pitch led display as a home TV product is still in the initial stage of testing the water. The problems are mainly the high cost, not suitable for long time viewing. And the smaller the pitch, the higher the price of the product, compared with the existing LCD TV, despite the size, power consumption and other aspects have obvious advantages, but the price short board is also obvious. Therefore, the most likely breakthrough of small pitch LED TV should be high-end villa large size private theater. In the future, with the decline in cost, the possibility of going into the living room of ordinary families is also there.

6. Small Pitch Display Control System:

Small pitch led display through the development of the past five years, there has been a huge improvement in the clarity of the high resolution led panel. As the density increases, the difficulty of further reducing the pixel pitch gradually increases.

 •  1). At the same time, the background support system of led wall display is undergoing a deep change. Display signal drive system (currently the market can be used is China’s Novastar and Colorlight system, the United Kingdom’s Brompton), which is commonly known as the sending card, receiving card. The transmitter card is embedded from the initial PCI slot, gradually developed to the configuration of independent power module external type.

And after the application of small pitch, the standard 1U rack type. These are only changes in appearance and access, in terms of the system’s carrying capacity, the transmitter card is gradually adapting to the standard video format of the video resolution of the carrying, the most typical such as support for 1080P signal single access; the introduction of HDMI interface input, etc., are in the front-end matrix with the small pitch signal access platform, spell control to do interface and resolution matching, NOVA’s H series control pixels can reach Several hundred million pixels.

 •  2). In terms of receiving card, single card with the ability to carry load as the pixel density of the display unit increases, the unit space is small, gradually derived from the strong carry load, small size of the memory stick type receiving card, such as NOVA’s A8S, A9S, A10S. and in the signal double backup, small pitch led display more traditional signal loop form, in the case of a stable and reliable system, this form can To do a certain degree of double backup role, but in the near future, more manufacturers will use the form of dual system card to replace the signal loop, so that the stability of the system to be more improved.

Can foresee, the system of receiving card suppliers in the search for business breakthroughs, there are also integrated circuit chip form of exploration and discussion, I believe it will not be too long, there will be a disruptive form of the display drive system to appear.

 •  3). In the video splicing wall signal access platform level, each level of equipment suppliers is also gradually from the rejection to accept small pitch led. from the current splicing wall standard hardware equipment splicing controller, the product from the initial interface fixed resolution output, to adapt to the small pitch led products signal access characteristics, the development of the interface resolution can be freely defined, SDI, DVI, HDMI or VGA.

From the initial led small pitch manufacturers industry-wide search for splicers that can customize the output resolution, to now the whole industry splicers have supported or are trying to support led splicing, which cannot be said to be a technical compromise and progress of the market.

We can easily find that led small pitch products in the traditional commercial display carrier, gradually penetrate the field of professional display, from the product itself, to the background system, all the time to adjust and improve.

 •  4). For led display system, in the current “intelligent” background, is the last link of data flow presentation. However, from the source of data collection, transmission links, data storage, decoding reproduction of various aspects of technical implementation have been to open interfaces, unified protocols, highly compatible direction, cannot help but say that the led display system has encountered an unprecedented opportunity to open the system.

In the context of big data, the integration of different stages of the system will be more rapid, led display system will be more open, in the system’s integrity, stability, linkage and control will be a higher level.

7. The Characteristics of Small Pitch LED Display Pamp Beads:

At present, the indoor splicing large screen market small pitch led display, DLP rear projection splicing screen, LCD LCD splicing screen in three parts of the world, where the small pitch led screen wall is the momentum is strong, it’s no splicing, high brightness, high gray, high contrast, long service life is unmatched by other splicing screen, but also recognized by the market, quickly grabbed a large share of the indoor splicing market. And bring such excellent performance to the narrow pixel pitch led display cannot be separated from the key devices applied in the manufacture of micro-pitch – led lamp beads:

• 1). The Characteristics of Small Pitch LED Beads:

A. 4-PIN RGB package, linear arrangement of chips.

B. Using black package substrate to improve color contrast.

C. Product weight is light, single LED weight as small as 1.0mg.

D. All-black RGB package is possible; 25% light loss.

E. The smallest size 0.5*0.5mm RGB package can be realized.

F. The surface of the product is matte, the screen light is softer.

G. Adopt silicone compression molding technology, improve the product temperature resistance, UV resistance, stress resistance.

Brightness 0~1200cd/㎡adjustable, with 160 degrees horizontal/vertical ultra-wide viewing angle, the whole screen runaway rate as low as one hundred thousandth, with a long service life of 100,000 hours, the average trouble-free working time of up to 50,000 hours, brightness uniformity of not less than 98%, chromaticity uniformity of ± 0.003Cx,Cy, with up to 99% of the light utilization rate, power consumption is only DLP and LCD Less than half of the power consumption of DLP and LCD, energy saving, environmental protection, easy maintenance, such outstanding performance, won the majority of user recognition.

• 2). The Importance of LED Beads:

A. LED beads are the most used components of micro-pitch led display, take P1.6 micro-pitch led display for example, the use of up to 360,000 per square meter.

B. The performance index of led beads directly affects the performance of the micro-pitch led display body and affects the audience’s evaluation of the display.

C. LED beads account for the largest proportion of the overall cost of the micro pitch led display, up to 30% to 70%.

• 3). The Impact of LED Beads on the Micro Pitch LED Display:

A. Impact on the brightness of the micro pitch led display depends on the size of the current flowing into the led beads and the brightness performance of the led beads themselves. the greater the current used by the led beads, the greater the luminous brightness of the micro pitch led display, good quality led beads have a good light conversion rate, a very small use of current can send a very high brightness of light, which is good for saving power consumption and maintaining the stability of the high resolution led display is good for saving power consumption and keeping stable.

B. Impact on runaway rate as the micro pitch led display consists of tens of thousands or even hundreds of thousands of groups of red, green, and blue led pixels, the failure of any color led will affect the overall visual effect of the display.

According to industry experience, the failure rate of hd led video wall assembly to aging 72 hours before shipment should not be higher than three ten thousandths (referring to the failure caused by the led lamp beads themselves), high quality led lamp beads failure rate is very low, the use of high quality led lamp beads micro pitch led display screen loss rate can be controlled at less than one hundred thousandth.

C. Impact on the service life of the led lamp beads theoretical life of 100,000 hours, far greater than the working life of other components of the micro-pitch led display, so as long as the quality of led lamp beads to ensure that the working current is appropriate, PCB thermal design is reasonable, display production process is rigorous, led lamp beads will be one of the most durable parts of the display machine, the use of high-quality led lamp beads micro-pitch led the service life of the display can reach 100,000 hours, and the mean time between failure (MTBF) can reach 50,000 hours.

D. Impact on the viewing angle the viewing angle of the micro-pitch led display is determined by the viewing angle of the led lamp beads. At present, indoor displays mostly use led beads with super wide viewing angles horizontally and vertically, making the horizontal and vertical viewing angles of micro-pitch led displays reach 160 degrees.

F. Impact on the pixel pitch led lamp bead size affects the pixel pitch of the led display and the resolution of the whole screen. SMD0707 type led lamp beads are mainly used in micro-pitch led display below P1.5, SMD1010 type led lamp beads are mainly used in P1.6, P1.9, P2.0 micro-pitch led display, SMD2121 type led lamp beads are mainly used in P2.5, P3 micro-pitch led display. SMD2121 led beads are mainly used for P2.5, P3 micro-pitch led display.

Under the premise of constant dot pitch, the increase of led bead size can increase the display area and reduce the sense of granularity, however, it will reduce the contrast due to the reduction of black area; on the contrary, the decrease of led bead size reduces the display area, increases the sense of granularity, increases the area of black area, and increases the contrast.

G. Impact on brightness/chromaticity/white balance consistency Micro-pitch led display is made up of countless red, green, and blue led pixels spelled out, and the consistency of the brightness and wavelength of each color led determines the brightness consistency, white balance consistency and chromaticity consistency of the whole display. Display manufacturers require device suppliers to provide led beads with a wavelength range of 5nm and a brightness range of 1:1.3, and these indicators can be graded by device suppliers through a spectrophotometric color separation machine.

Since led beads are angular, the micro led display also has angular directionality, that is, when viewed at different angles, its brightness is increasing or decreasing. Thus, the angular consistency of red, green, and blue LEDs will seriously affect the consistency of white balance at different angles, which directly affects the video color fidelity of the display. To do red, green, blue three LEDs in different angles when the brightness changes match the consistency, the need for strict scientific design in the package lens design, the choice of raw materials, which depends on the technical level of the package supplier.

The white balance of the normal direction of the display is good, if the angle consistency of the led beads is not good, the white balance effect of the whole screen at different angles will be bad. the angle consistency characteristics of the led beads can be measured by the led angle integrated tester, especially important for medium and high-grade display.

H. Impact on the anti-static ability led beads are semiconductor devices, sensitive to static electricity, very easy to cause static failure, so the anti-static ability is crucial to the life of the display. High-quality led beads can withstand 50Hz, 1500V (AC rms) test voltage for 1 minute without insulation breakdown.

I. Impact on the attenuation characteristics of the high resolution led panel will appear after a long time of work brightness decline and hd led video wall color inconsistency phenomenon, mainly due to the brightness of the led lamp beads attenuation caused by the led lamp beads attenuation will cause the display screen brightness reduction. Red, green, blue led brightness attenuation amplitude inconsistency will cause the led display high resolution color inconsistency, is what we often say the phenomenon of the display flower.

High-quality led lamp beads can well control the brightness decay amplitude. According to 1000 hours of room temperature light 20mA standard, red attenuation should be less than 2%, blue, green attenuation should be less than 10%, so blue, green led in the display design try not to use 20mA current, it is best to use only 70% to 80% of the rated current. Attenuation characteristics in addition to the red, green, blue led characteristics related to the use of current, PCB board thermal design, the use of the display environment temperature, etc. have an impact on the attenuation.

8. Core Technology of LED Small Pitch Display:

Along with the development of led technology, the brightness of led electronic display is also increasing, and the size is getting smaller and smaller, which means more and more indoor led small pitch display into the indoor will become a trend.

• 1). Effectively Reduce the Dead Light Rate

According to industry standards, the traditional led display dead light rate is as high as tens of thousands, but the small pixel pitch led display cannot be done for the time being, if there is a dead light on 10,000 square meters according to the previous standard, the display is almost impossible to watch. Therefore, the dead light ratio of
 
display must be controlled at one hundred thousandth or even one millionth to meet the needs of long-term use, otherwise, if many dead lights appear in a period, the user cannot accept.

• 2). Low Brightness and High Grayscale

Many people know that the human body sensor and outdoor lighting requirements for brightness is different, need to have a high refresh rate and energy-saving requirements, and indoor lighting more need to reduce the brightness, experiments show that from the perspective of the human eye sensor, led (active light source) than the passive light source brightness is two times higher, in terms of specific data, the best brightness of small pitch led display into the room is 200-400cd / m2. However, the grayscale loss caused by the reduction of brightness needs to be supplemented by technology.

• 3). System Power Double Backup

Small pitch led display any set of modules can be repaired from the front, maintenance is faster and more convenient; maintenance speed is more than 5 times faster than traditional products, stable operation, failure rate can be offset, power signal double backup, to ensure long and stable operation, support 7 * 24 hours continuous work.

• 4). Support System Access and Multiple Signals

Relative to outdoor video wall displays, small pitch led display signal display has the characteristics of multiple signal access and complex signal access, such as multi-location video conferencing, the need for remote access signal, local access signal and multi-person use access, etc. It has been experimentally proven that the simple use of split-screen solutions to achieve multiple signal access will reduce the signal standard. How to solve the problem of multiple signals, complex signal access, the need for fine pitch led video wall in the technical support.

• 5). Realize Seamless Splicing and Fast Correction

The biggest advantage of small pitch led display is seamless, but the requirements for splicing are higher. For LCD, if the splicing is even, there is no problem, and the seam line is not obvious. But this cannot be the case with small pitch led displays. If the squeeze between modules is too tight, there will be bright lines, and when the modules are left, there will be dark lines. Therefore, it is difficult to find the right splicing. So, it needs to provide some guarantee for the processing technology of the box, calibration technology and the guarantee of efficiency and good combination.

9. Nova HDR High-Definition Solution for Small-Pitch Display

In the led small-pitch display application, the image quality is always the core of the user’s attention. The advantages of the led display with high brightness and wide color gamut are not fully presented; also, some industry problems, such as uneven gray scale, low gray Accurate, etc., make the big led video wall quality in general, the human eye close viewing experience is not good.

To make the led display bring more real expressive power, the team of Nova scientists has been conquering a series of image quality problems for several years, and constantly enriching the content of high-quality display:

• 1). Support UHD / 4K Resolution for More Details:

A. 18-bit + technology, 4 times display grayscale enhancement, making the gradient more delicate and natural.

B. Fine grayscale technology for more accurate low-gray effect.

C. HDR10-Optima & HLG incorporates optimized tuning technology for led displays for a highly dynamic immersive experience.

• 2). Accurate Analysis, Real Display

MCTRL4K independent master control, with A8S / A10S receiving card, from the two dimensions of resolution and image quality to enhance the display effect, truly achieve 4K high-quality rendering, especially for the four-in-one and COB Display quality improvement.

Whether it is a conference, monitoring room, exhibition hall, or a radio and television live room, a commercial display, an indoor video wall display equipped with Nova’s high-quality solution can bring a better visual experience and deepen business value.

10. LED Small Pitch Display for Control Room:

The primary purpose of a display wall in any control room is to provide situational awareness and a useful common operating picture for multiple operators to simultaneously view relevant information and collaborate in critical decision‐making processes.

Display systems in control rooms should be treated differently than display systems used in boardrooms, auditoriums, signage, and short‐term viewing applications, because operators need to sit in front of the screens for longer hours monitoring critical information and handling incidents. The capability to interact efficiently with the display fine pitch led video wall defines operational efficiency and alertness.

Screen size, resolution of the individual screens, the resulting optimal visual acuity, sill height (distance from floor to bottom of screens) and available ceiling height are critically important considerations in effective control room design.

Optimal Visual Acuity is the maximum distance at which a person with normal vision can resolve the given pixel size. In a control room this is the recommended distance from the screen to the first row of operators. Beyond this optimal distance, resolution is wasted. Closer than this optimal distance, information space is wasted, and the display may be fatiguing to the operators. When designing a control room, you must consider:

 •  1). Space between the first row of operators and screen. Depth of the operators’ desks (consoles) and the available space in between the console and screen should be considered to permit free movement in the control room.

 •  2). Available ceiling height and sill height. Ensure that when seated or standing at the console, the operators have clear visibility of the entire image area. Often operators need to look over the monitor on their desk to the display wall. If the bottom of the screen is too low, important information may be lost and screen resolution is wasted.

 •  3). To avoid eye strain, it is recommended that the closest operators to the hd led wall should not be able to see the pixel structure of the displays. Optimum viewing distance is the distance before pixel structure is detected.

 •  4). It may also be worth noting that smaller displays would have more screen gap area than larger screens. The largest screen size that can meet the application’s minimum viewing distance would be preferred when considering screen‐to‐screen gap, cost (less units to fill the same size space) and power consumption.

11. Essential Knowledge to Buy Small Pitch LED Display:

led small pitch display can be described as a hot product in the industry, it is widely used in security monitoring, command centers, high-end conference rooms, high-end hotels, and other scenes. So, the necessary knowledge when buying small pitch led video wall screen:

 •  1). Comprehensive consideration of point spacing, size and resolution: Point spacing, size and resolution are some of the more important factors when people are in the small pitch led display. In practice, it is not the smaller the pitch, the higher the resolution, the better the actual application effect, but to consider the screen size, application environment and other factors.

The smaller the pitch of the small pitch led display products, the higher the resolution, the higher the price. Users in the purchase of products should fully consider their own application environment and program budget, to avoid the dilemma of spending a lot of money but cannot achieve the desired effect.

 •  2). Fully consider the maintenance cost: Industry users in the selection of small pitch led display products, to consider not only the purchase cost, and high maintenance costs. In practice, the larger the size of the screen body, the more complex the maintenance process, maintenance costs will naturally increase accordingly. In addition, the power consumption of small pitch is not easy to underestimate, large size fine pitch led display later operating costs are generally higher.

 •  3). Signal transmission compatibility is important: fine pixel pitch led display indoor signal access with diverse, large number, location dispersion, multiple signals with the screen display, centralized management, and other requirements, in practice, small pitch led display to efficient application, signal transmission equipment must not be taken lightly.

In the fine pixel pitch led displays market, not all small pitch led display can meet the above requirements, in the purchase of products, do not pay one-sided attention to the resolution of the product, to fully consider whether the existing signal equipment to support the corresponding video signal.

 •  4). LED small pitch display attracts users with its ultra-high-definition display screen and delicate display effect. Small pitch led display uses a new production process, completely overcoming the difficulties of traditional SMD small pitch cannot customer service, breaking the bottleneck of fine pitch led display moisture-proof, dust-proof, and impact-proof.

Small pitch maintenance operation is simple, without any tools, support module, power supply before maintenance, fast, low cost. 160 ° large viewing angle, 16bits high gray scale, indoor high brightness display, fantastic picture display effect, the picture is realistic and gorgeous.

12. Small Pitch LED Display Production Process Analysis:

• 1). Package Technology

The display below P2 density generally adopts SMD1212 lamp, LED pin shape using J or L packaging method. Lateral welding pin, welding area will be reflective, poor inking effect, inevitably need to increase the mask to improve contrast. Further increase in density, L or J package will not meet the application needs, must use QFN packaging method. No lateral welding pins, no reflection in the welding area, thus making the color rendering effect very good. In addition, the use of all-black integrated design molding, screen contrast ratio increased by 50%, display application picture quality effect compared to the previous display more excellent.

• 2). Mounting Technology

Micro pitch display RGB devices position of the slight offset will lead to screen body display uneven, is bound to require mounting equipment with higher precision.

• 3). Welding Process

Reflow soldering temperature rise too fast will lead to unbalanced wetting, which will inevitably cause the device to shift in the process of wetting imbalance. Too big wind cycle will also cause the device displacement. Try to choose more than 12 temperature zone reflow soldering machine, chain speed, temperature rise, cycle wind as a strict control items, that is, to meet the needs of welding reliability, but also to reduce or avoid the displacement of the device, as far as possible to control the demand range. Generally, 2% of the pixel pitch range as the control value.

• 4). Printed Circuit Board Process

Along with the development trend of micro-pitch display, 4-layer, 6-layer board is used, printed circuit board will use micro-perforation and buried hole design, printed circuit graphics wire fine, micro-perforation narrow pitch, the mechanical method used in processing drilling process technology can no longer meet the requirements, the rapid development of laser drilling technology will meet the micro-perforation processing.

• 5). Printing Technology

Too much, too little amount of solder paste, and printing offset directly affect the welding quality of the micro-pitch display lamp. The correct PCB pad design needs to be implemented into the design after communication with the manufacturer. The correct size of the stencil opening, and printing parameters are directly related to the amount of printed solder paste.

Generally, 0.1-0.12mm thickness of electropolished laser stencil is used for 2020RGB devices, and 1.0-0.8 thickness of stencil is recommended for devices below 1010RGB. The thickness, opening size and tin volume are proportionally increasing. Micro-pitch led soldering quality is closely related to solder paste printing. The use of printing machine with thickness detection, SPC analysis and other functions will play an important role in reliability.

• 6). Screen Assembly

The assembled box needs to be assembled into the screen body before it can display the refined picture and video. But the box itself size tolerance and assembly cumulative tolerance on the micro pitch display assembly effect cannot be ignored. The pixel spacing between the box and the box near the device is too large, too small will lead to display dark lines, bright lines. Dark line, bright line problem is now micro-pitch display cannot be ignored, the need to urgently overcome the problem. Some companies adjust it by putting 3m tape and box fine adjustment nut to achieve the effect.

• 7). Cabinet Assembly

Boxes are different modules spliced together, the flatness of the box and the gap between the modules is directly related to the overall effect of the box after assembly. Aluminum processing box, cast aluminum box is now widely used box type, flatness can reach 10 silk, module splicing gap between the two modules close to the pixel spacing for evaluation, two pixels too close to the light is bright lines, two pixels too far will lead to dark lines. Before assembling, we need to measure and calculate the module splicing gap, and then choose the relative thickness of the metal sheet as a jig to insert in advance for assembling.

• 8). System Card Selection

Micro pitch displays bright and dark lines and uniformity, color difference is the accumulation of criticism of led device differences, IC current differences, circuit design layout differences, assembly differences, etc. Some system card companies can reduce bright and dark lines and brightness, chromaticity unevenness through the correction of software. High-performance system cards are selected to correct the brightness and chromaticity of the small pixel pitch led display, which makes the flexible led high resolution display reach a better brightness and chromaticity uniformity and achieve a better display effect.

13. COB Technology Is Superior to SMD in Small Pitch LED Display:

In the field of led displays, with the development of upstream packaging technology, two different technologies for preparing led display panels have gradually emerged: SMD and COB. we can use these two technologies to produce small-pitch miniature led displays. We will share with you some information about these two technologies.

SMD is known as surface mount device, which refers to the use of surface mount technology to package LED products. It allows for the encapsulation of light cups, holders, crystal elements and other materials into different sizes of light beads. When producing display units with different pitches for miniature LED displays, the beads are soldered to the circuit board through high-speed SMT machines and high temperature reflow soldering.

Considering the technical difficulties in the packaging process, manufacturers prefer SMD to produce small size digital displays. SMD is the main technology for miniature LED displays with pixel pitch less than 10mm in the market.

On the other hand, COB, which stands for chip-on-board, is a new packaging technology that packages LED chips, rather than LED lights, directly onto the PCB. As a result, COB-LEDs will be freed from the physical size of SMDs for higher resolution. Cobs are available in P0.5 mm, P0.6 mm, P0.9 mm and P1.2 mm digital displays.

Compared to SMD, COB has several distinct advantages. The first advantage is high reliability. The mortality rate of miniature LED displays using COB packaging technology is much lower than the industry standard.

The reason for the high reliability is that COB led display technology eliminates the control link in the production process of a single lamp. In addition, it removes the lamp beads from the reflow process, so the high temperatures found in traditional methods do not affect the LED chips and solder lines.

Excellent heat dissipation and oxidation resistance also contribute to reliability. What’s more, COB uses high-standard coating technology to prevent led display failures caused by water, moisture, UV and other damage. It supports all-weather operation and can still operate in extreme temperatures from 30 to 80 degrees. A comprehensive protection process prevents bumps or scratches. If it gets dirty, the mini-LED display can even be cleaned with a damp cloth.

The second advantage of COB screen is that miniature led displays are easier to implement at smaller dot pitches. When designing the lamp bead diameter, COB is no longer limited by the size of the holder. As a result, it can cover the market below P1.0mm, which SMD technology cannot reach.

In addition, there is no denying that COB has better physical properties. modules in COB packages are not only lighter than those in SMD packages, but also have a larger field of view. Unlike SMD modules, COB led module can be bent at will, which are usually flexible at around 125 degrees.

With the above information, you may notice that COB technology is superior to SMD technology in led displays. If you are looking for high resolution micro led display, we have won a significant market share in many types of led video wall module. Certified by TUV, EMC, CE and RoHS standards, our products enjoy a high reputation worldwide.

• 1). Packaging Technology Difference

Now our conventional led display adopts surface mount SMD package, this package technology is to fix the led chip through the bracket, add epoxy resin curing inside, then fixed in PCB board through solder paste, then reflow soldering, let the led beads evenly arranged on the board, but this technology process is tedious, need certain operation time, and the minimum point spacing can only do 1.2, even if more Combined can be carried out to a smaller, but still cannot get rid of the problem of falling lights.

The COB package simplifies the packaging process of LED chips, LED chips directly integrated in the PCB board, the above glue fixed, the whole process is simpler, no reflow soldering, LED chips are more stable, while the point spacing can also be smaller.

• 2). Point Pitch Difference

Ordinary SMD package LED display is limited by the packaging technology, its point pitch is usually above P1.2, such as P1.2, P1.56, P1.875, P2.0, P3, P4 and so on, small pitch products are affected by welding technology, there will be lamp beads off and other phenomena, its development is limited mainly by the inability to achieve a point pitch below 1.0, resulting in the screen The resolution of the screen cannot continue to improve, if it is some of the picture quality requirements of high clarity occasions, it is not very suitable.

And COB package display can do smaller point spacing, such as P1.2, PO.9, PO.6 three products are using COB package, and the technology is mature, basically no drop light, greatly improving the overall resolution, screen clarity higher.

• 3). Stability Difference

Traditional LED display in the production and transportation, installation, because the lamp beads are exposed on the surface, finger touch or in the installation of other things collision will produce lamp beads off, resulting in a pixel does not light, mainly because its lamp beads are welded to the PCB board, collision to easily lead to drop lights, later if you want to repair can only be the technical staff to the scene welding or direct replacement of the unit board, resulting in a high after-sales rate.

And COB package displays better protection performance, in the installation and use of the process will not cause the lamp beads fall, so its surface is also more resistant to collision, stability greatly improved.

Basically, the main difference between cob display and led display comparison is the above three points, from the industry development, COB screen will be the future mainstream direction, COB display and traditional surface mount technology display compared, has high reliability, low cost, small pitch, wear and impact resistance, heat dissipation ability and many other advantages.

14. Features of New HD LED Screen:

Digital world is changing rapidly to seize the opportunities of the times. High resolution led display provides the efficient information services with excellent effects and video processing capabilities.

• 1). Product Features

Design in accordance with the 16:9, display unit in the aluminum cabinet design, one-time integral die-casting, magnesium alloy in the modular video wall bottom shell. With the anti-electromagnetic radiation, anti-shock, fan-less, dust-proof, and noiseless design.

• 2). Technical Advantages

With LCD to first led display the screen working status; the magnetism triggers the active front maintenance system to achieve up to 5 seconds of pre-maintenance and higher module restoration accuracy.

• 3). Structure Features

A. Temperature, power, signal, working hours system test, button and display synchronization, hidden power signal connector, embedded handles.

B. All components adopt leading precision machining technology to ensure product assembly accuracy≤0.1mm;. Automatic industrial 4.0 production line to reduce manual participation and ensure product assembly accuracy.

C. The cabinet has precise up and down and side to side seam sewing adjustment mechanism, which protects the led light during the assembly process.

• 4). Light Cabinet

Standard aluminum frame structure which is easy for on-site assembly and ensures the reliability of precision.

• 5). Test And Certification

All parameters exceed industry standards, series of products have passed 3C and CE certification, test reports of protection level, noise, flame retardant and smoke, issued by national authorities.

• 6). Practical Function

Useful functions, such as eliminating the residual image circuit design, eliminating the effect of residual image on the high quality led screen effect when the screen goes dark, reading the correction data function automatically, replacing the module on-site and updating and operating n data automatically.

15. Small Pitch LED Display Trends:

• 1). Ultra-small Pitch Products

The current small pitch products are basically between P1.2 and P2.5, and some industry insiders believe that the point distance will be further reduced and develop in the direction of “ultra-small pitch”. Small pitch led products have also entered the stage of homogeneous competition, to develop more high-definition products, to improve product competitiveness, technical recognition, has also become one of the choices of manufacturers, which also promotes the development of led display to the direction of ultra-small pitch.

• 2). Interactive Intelligent Demand

Intelligence is highly sought after and has a corresponding impact on people’s daily life and business activities, which also makes manufacturers start to conduct research and development to combine intelligent factors such as face recognition and gesture remote control with led displays.

• 3). Visual Experience Upgrade

The current pursuit of people’s visual experience is getting higher and higher, also prompted the led display in the form and display form of continuous innovation. LED transparent display is in such a trend quickly gain market recognition, smoothly cut into the high-end commercial display, stage display market.

The combination of high-resolution micro led display and holographic, can be said to be a combination of virtual and real display form, more evidence of people’s relentless pursuit of visual effects. In addition, 3D, VR and other emerging display technologies are applied to the trend of led 4k led video wall, but also further develop the use of led display field, will help the continuous expansion of the led display market.

• 4). Small-pitch LED Theater Applications Accelerate the Start

In recent years, driven by technological upgrading and market competition, small pitch led screen enterprises have been exploring how to “unlock” new applications of small pitch led. Especially under the impetus of mini-LED and micro-LED technology, the attention to high-resolution large-size applications continues to rise, and the application of led cinema screens is gradually accelerating.

Compared with traditional digital cinema projectors, the innate advantages of small-pitch led in brightness, so that it cannot only meet the dark environment to watch, but also in a bright environment, which makes fine pitch direct view led video displays not only to provide a unique new experience of viewing, but also to meet the needs of the conference, concert, event broadcast and other commercial activities.

At the same time, the full hd led screen has a wide color gamut, with 1024-4096 levels of gray control, realistic color, along with mini-LED, micro led technology landing application, its resolution is enough to achieve 4K, 8K application needs. Better picture quality also makes it the focus of movie fans chasing a better movie viewing experience.

Along with the small pitch led movie screen in many places around the world gradually settled, a theater projection technology revolution is also in the making. The application of led cinema screens has stepped on the starting line and has the potential to accelerate.