LED Display Screen Vocabulary


Introudction of the LED Display Screen Vocabulary and expressions.

1、Pixels,Pixel diameter,Pixel pitch
1.1 Pixels
Minimum luminous LED Display unit, the same with ordinary computer monitor . LED display of each light emitting unit may be individually controlled called pixels.
1.2 Pixel diameter
∮ means each pixel diameter led light pixel diameter, in millimeters
 1.3 Pixel pitch
Center two-pixel distance between the led display is called pixel pitch, also known as the dot pitch. More dense spacing within the higher pixel density per unit area, the resolution is also high, the cost is high. Pixel diameter is smaller, the smaller the dot pitch.
2、Resolution Ratio
2.1 Module resolution
LED Modules horizontal pixels multiplied by the vertical pixels
2.3 LED Display mode
It is composed by several pixels, structure independent,it can composed the smallest unit of the led screen. , such as 32*16, 32*32, 64*32 led modules etc.
In a given direction, the luminous intensity per unit area on. Brightness of the unit is cd/sqm
The brightness of LED depends on the material of led lamps, encapsulation mode and sizes. The bigger of led chip
The higher the brightness, other wise,the lower the brightness
4、Grey level
LED display in the same level of brightness from the darkest to the brightest to the difference between the brightness of the series.Used to show a video screen display, each color should be gray processing capacity of 256 (8 bit)
       Gray level depends on the video source and control system, dealing with figures.At present domestic LED display mainly adopts eight processing system, namely 256 (28) grey level.Simple understanding is a total of 256 from black to white brightness changes.Use RGB trichromatic can constitute a 256 x 256 x 256 = 16777216 colors.Known as the 16 million colors.
5、Contrast ratio
Under the certain environment illumination, LED display the ratio of maximum brightness and background brightness
  Contrast ratio=luminance/non-luminance (reflect bright)
      In order to be able to show the brightness uniformity of words and images, is not affected by ambient light, screen should have enough contrast.For LED display, contrast to 4096: more than 1 effect is good.

6、White Balance
White LED display can be made from a mix of RGB tricolor in proportion. The ratio for R:G:B=3:6:1
Color Coordinate---CIE chromaticity diagram
7、 Pixel un control rate
       Refers to the minimum imaging display unit (pixels) work is not normal (control) the proportion of
There are two patterns for un-control rate.
a)blind spot: when need it bright, it dark , called blind spot
b)Bright spot,When need it to be dark, then it always bright. Call bright spot
8.Generally, pixels have 2 r1g1b (two red, one green and one blue light), 1 r1g1b, 2 r1g, etc., and out of control does not generally is red, green, and blue light in the same pixel all out of control at the same time, but as long as one lamp is out of control, we think this pixel is out of control. 
In accordance with the regulations of the industry standard SJ/T11141-2003, indoor screen pixel rate should be not more than three over ten thousand out of control, and outdoor screen pixels is out of control rate should be not more than two over one thousand, and the discrete distribution.
9 refresh frame frequency
The number of unit time display screen information update;General is 25 hz, 30 hz, 50 hz, 60 hz, etc., in the frame frequency is higher, change the image of the continuity, the better
10.1 static screen and scanning screen
When display text, images, video, LED display lights on the spot when the display is light shining at the same time;
10.2 Scanning screen
Use of persistence of vision characteristic of human eyes, in a very short period of time will LED display all light respectively
At present, scanning screen is commonly a quarter flicking and flicking, 1/16, 1/8, 1/8.Also for adaptation of different resolution, and the setting of other scanning;
Scanning screen and static screen at the request of the display brightness is different, in the same light tube with the same brightness, static screen is higher than scanning the brightness of the screen, so the static screen commonly used outdoors, and scanning screen commonly used indoors
11、 Best viewing distance, minimum distance
11.1 Best viewing distance
Can see on the display content, just completely and not flat color, image content is the most clear position relative to the screen body vertical distance
11.2 Minimum distance
For a certain shape, brightness, distance of two points of light, unable to determine the position of the two points to the minimum vertical distance of two points
The influencing factors of minimum stadia and minimum perspective:The shape of the light spot, Brightness, distance
 Best viewing distance =pixel pitch /(0.3-0.8)。unit:m
        e.g.:P4(φ3)the best viewing distance:5--13.3m;

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