Full color LED display with excellent brightness and color performance, as well as seamless picture integrity, more and more favored by the market. However, some cities also have some problems, such as the LED display screen brightness is too high to affect the surrounding residents' life, traffic and other aspects. How to adjust the brightness and color of LED display screen, here Huabang Ying optoelectronic small editor to share a few tips.
Selection of primary color wavelength
LED displays are widely used in various industries, and different applications have different requirements for the wavelength of the primary color of the LED. Some of the wavelengths of the primary color of the LED are selected for good visual effects, and some are for people Some of them are regulated by industry standards, national standards and even international standards. For example, the choice of the wavelength of the primary color of the green tube in a full-color LED display; in the early days, people generally used a yellow-green LED with a wavelength of 570nm. Although the cost is low, the color gamut of the display is small, the color reproduction is poor, and the brightness is low. After choosing a pure green tube with a wavelength of 525nm, the color gamut of the display has nearly doubled, and the color reproduction has been greatly improved, which greatly improves the visual effect of the display. For another example, on the stock market display screen, people are usually used to using red to indicate stock price rise, green to indicate stock price decline, and $ to indicate flat market. In the transportation industry, the national standards strictly stipulate that the blue and green bands are for traffic and the red band is forbidden. Therefore, the choice of primary color wavelength is one of the important links of LED display screens.
1. Modulate the pulse width, use the changing frequency that the human eye can feel, and use the pulse width modulation method to achieve grayscale control, that is, periodically change the light pulse width. Pulse width modulation is more suitable for digital control and has been widely used. The most common method is to adopt a microcomputer. At present, almost all LED displays adopt pulse width modulation to control the gray level.
2. Ordinary LED tubes allow a continuous task current of about 20 mA. By changing the current flowing through the LED, except for the saturation of the red LED, the brightness of the remaining LEDs is basically proportional to the current flowing.
Adjustment of white field color coordinates
White field color coordinate adjustment is one of the most basic technologies for full-color LED displays. However, in the mid-1990s, due to the lack of industry standards and basic testing methods, the white-field color coordinates were usually determined by human eyes and sensations, resulting in serious color cast and randomness of white-field color temperature. With the promulgation of industry standards and the completion of testing methods, many manufacturers have begun to standardize the color matching process for full-color screens. However, due to the lack of theoretical guidance for color matching, some manufacturers often adjust the color coordinates of 100 fields at the expense of gray levels of certain primary colors, and the overall performance cannot be improved.
The high-definition LED display is displayed according to the principle of light's three primary colors. Determining one of the red, green, and blue colors as the reference is mainly based on the different brightness of the red, green, and blue colors of the selected product. Generally, the brightness reference is the one with low brightness ratio. When the maximum brightness has been reached, it is necessary to adjust another color for a two-color LED display, and for a full-color LED display, the colors of the other two LEDs must be adjusted.