The production and application of LED traffic guidance screens involved multiple technologies, including: semiconductor, optoelectronic technologies, integrated circuit, image processing and transmission, computer network communication, and manufacturing of electronic products. LED screens of different types and different performances will have huge differences in the aspect of material constitution, production process and control. Even products with same types and same performances but from different manufacturers, still have differences due to the different technologies used by these companies. LED traffic guidance screens can accurately transmit the real-time traffic information to drivers. They have following characteristics:
1) High brightness, reasonable visual angles:
Road traffic-induced information is mainly oriented to vehicles traveling on the road. They have less demand on visual angles. ±30o is sufficient. LED screens outside traffic guidance rooms should work in 24 hours. In the condition of direct sunlight, the display contents should be visible. It is required that LED traffic guidance screens should have a certain level of brightness. The visual distance under normal circumstances should be around 200m.
2) Red, green yellow will be three major display colors
The release of traffic information is mainly oriented to dynamic vehicles. Within the visual distance, dynamic vehicles stay for a very short time. Complex multi-grayscale graphics and animation content should be replaced by simple graphic logos or texts. Red, green and yellow are three prime colors that used in traffic signs, red represents stop, green represents suggestion, and yellow represents warning.
3) The brightness of screens can be automatically adjusted
LED traffic guidance screens normally worked on 24 hours in any environmental conditions. Makers should make sure that these their products are clearly visible during the sunny daytime with the maximum brightness, and also avoid the glare in rainy days and nights. Thus it requests that these screens should be capable of automatic adjusting. In normal conditions, the automatic adjusting range should not less than 8.
4) Remote control, intelligent detection
The installation passion of LED traffic guidance screens is distributed over a large area. Remote intelligent control systems are necessary. The widely distribution of LED screens makes the daily testing and maintenance work become more difficult. Remote control system can intelligently detect faults and do some simple adjustments. It is also a very important part of the intelligent transportation system.