|How to enhance the brightness of the LED screen.|
The two LED brightness is the effective use of the light generated from the wafer, to increase the amount of irradiation of the light irradiated to the expected direction; Another is to increase the wafer (chip) itself luminescence amount. If the LED screen brightness of less than the expected value found in the use, you can also try to use the following method to increase the brightness. The former is to try to increase the luminous efficiency of the active layer of the wafer, LED track lights, as well as increase external light extraction efficiency, improve the shape of the wafer or the wafer is large-scale utilization of high current density to increase the amount of light emission; the latter is the use of lightwave control technique, i.e. the use of encapsulating resin to form a special optical structure, so that the light irradiation of the wafer to a desired direction.
Change the current flowing through the LED production, to General LED tube allows continuous current of 20 mA, in addition to the red LED saturation, the other LED brightness is essentially proportional to the current flowing.
The contents of the serial transmission of the scanning plate each LED switching signal but an 8-bit binary luminance value. Each LED has its own pulse width modulator to control the lighting time. Thus, in a repeating cycle of light, each pixel in the 16-level grayscale only need four pulses, only eight of the 256 gray scale pulse and greatly reduce the frequency of the baud. Can be easily achieved with this decentralized control LED gray 256 gray scale control.
Use the the human visual inert, to achieve gradation control with pulse width modulation method, the optical pulse width (i.e. duty cycle) is periodically changed, as long as the repeating cycle of light is short enough (i.e., the ““refresh”” rate high enough), the human eye is feeling less than a light-emitting pixel jitter. There are two types of serial transmission control signal: a centralized control of each pixel grayscale scan board scan board from the control box of each row of pixel luminance value decomposition (i.e. pulse width modulation) , and then each line of the opening of the LED signal in pulses (lit, not lit 0) line serial transmission to the corresponding LED control whether the light.
Since the pulse width modulation is more suitable for digital control, so in today commonly used by the microcomputer to provide a LED factory display contents, almost all of the LED control system usually consists of three parts of the master box, the scan board and the display control means. The main control box from the computer's graphics card for one screen pixel colors brightness information, and then re-allocated to a number of pieces of the scanning plate, each scan board is responsible for controlling the LED screen on the number of rows (columns), and each row (column) on the LED display and control signal with serial transmission. Used in this way the device is less, but the serial transmission of a larger amount of data, in a repeating cycle of light, each pixel requires 16 pulses in 16 grayscale in 256 levels of gray, 256 pulses, the device operating frequency limit, generally only the LED screen to do the 16-level grayscale.