What is the meaning of single and double color LED screen?
Author:Li Jinxia Time:2021-06-09 08:01 Browse(458)
Popular point understanding is: monochrome refers to a color luminous LED screen, generally in the store above the single red word screen, the main colors are: single red, single yellow, single green, single white
Popular point understanding is: monochrome refers to a color luminous LED screen, generally in the store above the single red word screen, the main colors are: single red, single yellow, single green, single whiteTwo color refers to the LED display screen composed of two colors of LED lights. Generally, the names of drugs are displayed in hospitals. Generally, there are two colors of red and green, which can display any color mixed with red and green, but can not display the blue part.
this paper introduces the design of two color LED display screenFull color LED screen refers to that led is composed of three primary colors of red, green and blue.

What is the meaning of single and double color LED screen?

it can display full-color pictures and videos.
it can display full-color pictures and videosI hope I can help you due to their low working voltage (only 1.5-3V).
they can emit light actively and have a certain brightness, which can be adjusted by voltage (or current), and have shock resistance, vibration resistance and long service life (100000 hours), At present, there is no other display mode that can match the LED display mode.
there is no other display mode that can match the LED display modeThe red and green LED together as a pixel production of the display screen is called two-color screen or color screen; The display screen with red, green and blue LED tubes as one pixel is called tricolor screen or full-color screen.
the pixel size of indoor LED screen is generally 2-10 mm.
several kinds of LED chips that can produce different primary colors are often packaged into one. The pixel size of outdoor LED screen is mostly 12-26 mm, and each pixel is composed of several monochrome LEDs. The common finished product is called pixel tube, Two color pixel tube is generally composed of 3 red and 2 green, and three color pixel tube is composed of 2 red, 1 green and 1 blue   No matter using led to make monochrome, bicolor or tricolor screen.
this paper introduces the design of LED screenTo display an image, the brightness of each LED that constitutes a pixel must be adjustable, and the fine degree of adjustment is the gray level of the display screen.
the higher the gray level is.
the more delicate the displayed image is, the richer the color is, and the more complex the corresponding display control system is.
generally, the 256 gray level image has very soft color transition, while the 16 gray level color image has very soft color transition, The color transition boundary is very obvious.
so.
at present, the color LED screen should be made into 256 gray level.
the color LED screen should be made into 256 gray levelSecond, the method of controlling LED brightness   There are two ways to control the brightness of LED.
one is to change the current flowing through the LED.
generally, the continuous working current of LED is allowed to be about 20 mA. Except for the saturation of red LED, the brightness of other LEDs is basically proportional to the current flowing through; Another method is to use the visual inertia of human eyes, and use the pulse width modulation method to achieve gray control, that is to change the light pulse width (i.e. duty cycle) periodically, as long as the cycle of repeated lighting is short enough (i.e. the refresh frequency is high enough), The human eye can't feel the jitter of the light-emitting pixels.
because PWM is more suitable for digital control.
today, microcomputer is widely used to provide LED display content, almost all LED screens use PWM to control the gray level.
in this paper, we introduce a new method to control the gray level of LED screens   The control system of LED is usually composed of main control box, scanning board and display and control device.
the main control box obtains the brightness data of a screen pixel from the display card of the computer.
then it is redistributed to several scanning boards, each scanning board is responsible for controlling several rows (columns) on the LED screen, and the display and control signals of the LED on each row (column) are transmitted in serial mode.
the main control box obtains the brightness data of a screen pixel from the display card of the computerAt present, there are two ways of serial transmission of display control signal: one is to control the gray level of each pixel on the scanning board.
the scanning board decomposes the brightness value of each row of pixels from the control box (i.e. pulse width modulation), and then transmits the turn-on signal of each row of led to the corresponding LED in the form of pulse (light is 1, no light is 0) in a serial way, This method uses less devices.
but the amount of serial transmission data is large, because in a repeated lighting cycle, each pixel needs 16 pulses at 16 gray levels and 256 pulses at 256 gray levels. Due to the limitation of device operating frequency, the LED screen can only achieve 16 gray levels   Another method is that the serial transmission content of the scanning board is not the switch signal of each LED, but an 8-bit binary brightness value.
each LED has its own pulse width modulator to control the lighting time.
in this way.
in a repeated lighting cycle, each pixel only needs 4 pulses in 16 level gray, and only needs 8 pulses in 256 level gray, The serial transmission frequency is greatly reduced.
with this method of decentralized control of LED gray level, 256 level gray level control can be easily realized.
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