Large Stadium LED display of how to meet the needs of the audience
Stadiums installed LED display and related key technical indicators are mainly display white point chromaticity coordinates, smoothness, brightness and uniformity, the largest line of sight, out of control pixel rate of viewing angle, contrast and so on. Its core requirement is to ensure visual clarity and comfort referee, the audience.
The maximum brightness
LED display the normal display brightness is to evaluate the quality of an important indicator. The higher the brightness of the display, the better the vividness of the image, the distance seems more clear, but it can not exceed a certain range, or give viewers visual fatigue will cause some light pollution. The maximum brightness test items in the first quantifiable hard targets, manufacturers and customers are more concerned about the project, there are certain requirements that detects environment, small changes in the general environment illumination, and to adjust the display to a high gradation and measured at the highest brightness level maximum brightness. The actual site inspection found in the normal direction of the display is the key to ensure detection accuracy. Due to the different display illumination environment, find the maximum brightness of the display is different. Therefore, the maximum luminance required targets buyers and sellers of contract as a test basis. The maximum brightness of the display is the first project in a fixed target, the majority of domestic display manufacturers are concerned about the project, most of the test results to achieve contractual requirements. The key is to find the optical axis is detected, followed by testing work should not have been used in the display after a fairly long period of time, it is recommended to use more than six months prior to detection of the display need to be cleaned. To ensure the best visual effects we configured the maximum brightness of the entire screen ≥5000cd / m, its maximum brightness in detail in Table 1.
Partial raised or recessed will lead LED display viewing angle of dead ends, in order to ensure the LED display image is not distorted, we must ensure flatness meet the requirements. Flatness measuring method is: the long side of the ruler is placed on the led screen at any position, ruler measuring the maximum gap between the sides of the display panel with plug. The electronic industry standards and Sports Industry Standard SJ / T11281-2003 "LED display test methods" and GB / T29458-2012 "stadiums LED display requirements and test methods" module splicing gap should be less than 2mm.
Maximum line of sight
For installation of the stadium screen, the venue should be formally fixed seat spectator most to meet the maximum sight distance requirements. LED display is the biggest line of sight means that under normal conditions of use, able to see the maximum distance LED display characters. Generally the product of character height and line of sight representation. It should make the formal fixation stadium seats more than 95% of the audience to meet the maximum sight distance requirements.
The maximum viewing distance and character height is calculated as: H = k • d
Formula: H = maximum line of sight, the unit is m;
k = horizon coefficient, generally take 345;
d = the height of the characters, the unit is m.
Pixels out of control rate
Emitting status and control requirements do not match the pixel that is the ratio of total pixels pixels out of control rate. Out of control pixel LED display include blind spots and often highlights categories. It detects a need to control the display show the white balance and red, green and blue color. At the highest gray level status led screen is cleared and the state, were observed in the control condition does not match the pixel and calculate the corresponding pixel runaway rate. The whole screen pixels out of control rate measurements: the entire screen with a few blind spots, and the entire screen with the ratio of the number of pixels of the entire screen is Always count the whole screen pixels out of control rate. Calculate the red pixels out of control rate; measure out the same way the blue pixel and green pixel runaway rate runaway rate. Take the maximum value as the whole screen pixels out of control rate. Measuring areas of pixels out of control rate is similar. Stadium (indoor sports venues) LED display control rate should be less than ten thousandths, stadium (outdoor physical exercise and competition venues, stadium for the comprehensive stadium) display control rate should be less than one thousand two-thirds, and is a discrete distribution.
According to GB / T29458-2012 "stadiums LED screen requirements and test methods", stadiums LED display horizontal viewing angle is not less than ± 50 °, vertical viewing angle of not less than 10 °, under the perspective of not less than 20 °.
Uniformity indicators pixel light intensity uniformity of the display module brightness uniformity and brightness uniformity module three. These indicators detected in the production process of the display is very scientific in quality testing products played an important role. Rarely detected in the actual detection of the whole screen, it is recommended to detect the production process and before shipment. Stadiums LED display inhomogeneity should be less than 10%.
The highest contrast
Contrast is under certain environmental illumination, the display brightness and the led display during normal operation completely turn off than the background brightness of the screen surface. This is an important optical performance reflects not only the display brightness situation also reflects the influence of the ambient light on the display.
As the highest contrast detection requires certain environmental illumination requirements, in field testing more difficult to achieve, but in the factory in the room is relatively easy and accurate detection of the higher-contrast display, viewers clarity as possible. Similar detection methods contrast and brightness, first measure the average luminance of the display during normal operation, and then also measure the average luminance of a black screen, then the calculation formula. According to sports venues LED display, when the background illumination is less than 20lx, display contrast should be able to reach 100e1.
The white color coordinates
White balance is one of the most important indicators display, white red, green, and blue mixed in the ratio of brightness is made. Will display the white balance adjusted according to the brightness of the test method were measured chromaticity coordinates screen surface a plurality of regional centers. Display white point color coordinates should be used wavelength indication error small absolute spectral color measurement instrument. Due to improved display control system technology, the display brightness for each color can be adjusted, so a good test results. If the result is relatively large, we need to re-adjust the mixing ratio of the three primary colors to achieve the best white field effect. However, the display shows white color temperature detected at the all-white image, so the current test results reflect only the tri-color luminance curve at the highest point of the coupling of luminance, luminance curve does not reflect all of the three coupling situation. White color coordinates test method to detect all-white image at the highest gray level and the highest brightness level. The white color coordinates according to the environment within the adjustable color temperature of 5000K-9500K, press CIE1931 color system, tolerance is Δx|≤0.030, |Δy|≤0.030.