1. Selection of the wavelength of the base color
LED screen in all walks of life has a very wide range of applications, and in different places of application of the LED color wavelength has different requirements for the selection of the LED color wavelength is to achieve a good visual effect, some are to conform to people's habits, and some are industry standards, National standards and even international standards. For example, the full color LED screens in the screen of green nanotube-based color wavelength selection; Early everyone generally choose the wavelength of 570nm yellow green LED, although the cost is low, but led large screen curtain color gamut, color reduction, low brightness. And in the selection of the wavelength of the pure green tube 525nm, led large screen color gamut widened nearly one times, and the color reduction degree greatly improved, greatly improving the LED screen visual effect. For example, the big screen of securities, people are usually accustomed to in red to indicate the rise in stock prices, the use of green to indicate a decline in share prices, and the use of $ to express flat plate. In the transport industry is the national standard strictly defined by the blue-green band to express, red band for the prohibited line. Therefore, the choice of the wavelength of the base color is one of the important links of LED screen.
2, brightness adjustment
(1), modulation pulse width (PWM), the use of human eye can feel the frequency of change, the use of pulse width modulation method to achieve the gray level control, that is, periodically change the width of the light pulse. Pulse width modulation is more suitable for digital control, has been widely used, the most common method is the adoption of micro-computer. At present almost all LED displays are adopted pulse width modulation to control the grayscale level.
(2), ordinary LED tube allows continuous task current at about 20 ma, by changing the current flow through the LED, in addition to the red led saturation phenomenon, the rest of the LED brightness is basically proportional to the current flow.
(3), white field color coordinates of the deployment
White field color coordinate leveling is one of the most basic techniques for full-color LED screen screens. However, in the mid 1990s, due to the lack of industry standards and basic testing methods, usually only rely on the eye, based on the feeling to determine the white field color coordinates, resulting in serious bias and white color temperature of the random color. With the promulgation of industry standards and the completion of testing methods, many manufacturers began to standardize full-color color process. However, there are still some manufacturers due to lack of color theory guidance, often at the expense of some of the base color gray level to allocate $number color coordinates, comprehensive performance is not improved.
(4), color adjustment
High-definition LED screen is the three-color principle of the installation of light display. Determine red, green, blue one of the colors as the benchmark is based mainly on the choice of products red, green, blue color of different brightness, generally as the brightness of the benchmark is a low percentage of brightness, when the benchmark has reached the maximum brightness, for the two-color LED display needs to adjust another color, For the LED full color, we must adjust the other two kinds of LED colors.