(1) pixel
LED display the smallest unit of light, with the ordinary computer display in the same meaning of the pixels; LED display can be individually controlled by each of the light-emitting unit called pixels.
(2) pixel diameter
Pixel diameter ∮ refers to the diameter of each LED luminescence pixel, in millimeters.
(3) pixel pitch
The central distance between the two pixels of the LED display is called the pixel pitch, also called the point spacing. The more dense the pitch, the higher the pixel density per unit area, the resolution is also high, the cost is high. The smaller the pixel diameter, the smaller the point spacing.
Second, the resolution
(1) module resolution
LED module horizontal pixels multiplied by the number of vertical pixels.
(2) screen body resolution
LED display horizontal pixels multiplied by the number of vertical pixels.
(3) LED display module
Composed of a number of display pixels, the structure of independent, can form the smallest LED display unit, typically 32 * 16,32 * 32,64 * 32 modules. The higher the resolution of the screen, the more content you can display, the more delicate the picture, but the higher the resolution, the more expensive the cost.
Third, brightness
In a given direction, the luminous intensity per unit area. The unit of brightness is cd / ㎡. The brightness and the unit area of the LED number, the brightness of the LED itself is proportional to; LED brightness and its drive current is proportional to, but the life and its current square is inversely proportional to, so can not be in order to pursue excessive brightness to drive current; at the same point density, LED The brightness of the display depends on the material used in the LED, package and size, LED chip, the higher the brightness; the other hand, the lower the brightness.
Fourth, grayscale
LED display the same level of brightness from the darkest to the brightest between the brightness level can be distinguished. The display is used to display the video screen. Each primary color should have 256 levels (8 bits) of grayscale processing capability; the gray scale depends on the number of bits processed by the video source and control system. At present, the domestic LED display mainly uses 8-bit processing system, that is, 256 (28) level gray. Simple understanding is from black to white a total of 256 kinds of brightness changes. Using RGB primary colors can constitute 256 × 256 × 256 = 16777216 kinds of colors. That is commonly referred to as 16 megapixel.
Fifth, contrast
The brightness of the LED display screen and the brightness of the background brightness; brightness = brightness (luminous brightness) / when the brightness of light; in order to be able to show the brightness of uniform text and images, from the surrounding light The effect of the screen should have sufficient contrast. For the LED display, the contrast to achieve more than 4096: 1 effect we go.
Sixth, white balance
LED display white can be mixed by the RGB three primary colors in proportion, R: G: B ratio of 3: 6: 1
Seventh, pixel out of control rate
Refers to the proportion of the minimum imaging unit (pixel) of the display that is not working properly (out of control). There are two modes of pixel runaway:
(1) blind spots, that is, blind spots, when the need to light it is not bright, called blind spots;
(2) bright spot, when it is not bright, it has been lit, called the bright spot.
In general, the composition of the pixels 2R1G1B (2 red, 1 green and 1 blue light), 1R1G1B, 2R1G, etc., and out of control generally will not be the same pixel in the red, green, blue lights at the same time all out of control , But as long as one of the lights out of control, we think that this pixel out of control. In accordance with SJ / T11141-2003 industry standards, the indoor screen pixel out of control rate should not be greater than three ten thousandths, outdoor screen pixel out of control rate should not be more than two thousandths, and for the discrete distribution.