Publisher: Supplier of LED Display Time: 2018-03-09 Views: 1567
1. Selection of primary color wavelength: LED displays have a very wide range of applications in all walks of life, and different applications have different requirements for the primary color wavelength of LEDs. Some of the choices for LED primary color wavelengths are to achieve good visual effects. , some are in line with people's habits, and some are industry standards, national standards or even international standards. For example, in the selection of the wavelength of the primary color of the green tube in the full-color LED display; in the early days, people generally chose a yellow-green LED with a wavelength of 570 nm. 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 is nearly doubled, and the color reproduction is greatly improved, which greatly improves the visual effect of the display. Another example is the stock market display screen. People are usually used to using red to indicate that the stock price has risen, green to indicate that the stock price has fallen, and $ to indicate a flat. In the transportation industry, it is strictly stipulated by national standards that the blue and green bands indicate passage, and the red band is forbidden. Therefore, the selection of the wavelength of the primary color is one of the important aspects of the LED display.
2. Brightness adjustment:
1. To modulate the pulse width, use the frequency of the change that the human eye can feel, and use the pulse width modulation method to achieve grayscale control, that is, to 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 use a microcomputer. At present, almost all LED displays use pulse width modulation to control the gray level.
2. The ordinary LED tube allows a continuous duty current of about 20 mA. By changing the current flowing through the LED, except for the saturation phenomenon of the red LED, the brightness of the other LEDs is basically proportional to the current flowing.
3. Allocation of white field color coordinates: The allocation of white field color coordinates 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 color coordinates of the white field were usually determined only by the human eye and feeling, resulting in severe color cast and randomness of the color temperature of the white field. With the promulgation of industry standards and the completion of testing methods, many manufacturers began to standardize the color matching process of full-color screens. However, due to the lack of theoretical guidance on color matching, some manufacturers often sacrifice the gray level of some primary colors to allocate 100-field color coordinates, and the overall performance cannot be improved.
4. Color adjustment: The high-definition LED display is displayed according to the principle of three primary colors of light. Determining one of red, green and blue as the benchmark is mainly based on the different brightness of the selected product red, green and blue. Generally, the brightness benchmark is the one with the lower brightness ratio. When the maximum brightness has been reached, another color needs to be adjusted for a two-color LED display, and the other two LED colors need to be adjusted for a full-color LED display.