How to improve LED display brightness correctly
Time:2018-10-08
Views:1162
The methods to improve LED brightness can be roughly divided into two types, namely increasing the luminous quantity of the chip itself.Another approach is to effectively use the light generated by the chip to increase the amount of light that reaches the desired direction.The former is to try to improve the luminous efficiency of the active layer of the chip, improve the chip shape and increase the efficiency of external light extraction, or to use the high-density current to increase the luminescence of the chip.The latter USES light wave control technology, which USES encapsulated resins to form special optical structures that allow the light generated by the chip to shine in the desired direction.
If the LED display fails to achieve the expected brightness after use, try the following methods to improve the brightness.
1. Change the current flowing through the LED. Generally, the LED tube allows continuous working current at about 20 milliamperes.
2. Take advantage of the visual inertia of human eyes and use the pulse width modulation method to realize the grayscale control, that is, to periodically change the width of the light pulse (namely duty cycle). As long as the cycle of repeated lighting is short (i.e. the refresh frequency is high enough), human eyes will not feel the jitter of luminous pixels.Since pulse width modulation is more suitable for digital control, in today‘s world where microcomputers are widely used to provide LED display content, almost all LED control systems are usually composed of the main control box, scanning board and display control device.The master control box takes a screen of pixel‘s colored brightness data from the computer‘s display card, and then redistributes it to a number of scanning boards, each of which controls a number of rows (columns) on the LED display, and the LED display signals on each row (column) are transmitted in series.
There are two types of serial transmission display control signal way: one is a centralized control each pixel gray scanning board, scanning board will come from the control box of the brightness values of all pixels decomposition (pulse width modulation), then all LED to the opening of the signal pulse form (0) light is 1, dawn in line with serial transmission to the corresponding LED on, whether to control its light.In this way, fewer devices are used, but the data transmitted in series is relatively large, because in a cycle of repeated lighting, 16 pulses are required for each pixel under level 16 grayscale and 256 pulses are required under level 256 grayscale. Due to the working frequency limitation of devices, LED display can only achieve level 16 grayscale.
3. The content transmitted in series is not the switching signal of each LED, but the brightness value of an 8-bit binary.Each LED has its own pulse width modulator to control the lighting time.Thus, in a cycle of repeated illumination, each pixel needs only 4 pulses at level 16 gray and only 8 pulses at level 256 gray, greatly reducing the frequency of serial transmission.This decentralized control method of LED grayscale can easily realize 256-level grayscale control.
分享
.jpg)
ChatNow