Decryption civilian aircraft power solid-state light source lighting technology

             Aircraft lighting (aircraft lighting) means for illuminating the cabin on the plane, make light signal and landing runway lighting equipment, lighting and machine into the machine and outdoor lighting and emergency lighting. The rapid development of solid-state light source technology to improve aircraft lighting brings opportunity.

 

Brief Background

 

Civil aircraft lighting system needs to achieve a variety of aircraft interior and exterior lighting function, and in strict compliance with quantitative performance requirements of the airworthiness regulations. Landing lights must provide sufficient illumination on the runway, so the pilot during approach, landing, taxiing and other ground phase can obtain sufficient information. Navigation lights, anti-collision light intensity values ​​and their distribution must be able to identify the aircraft contour and flight direction, to provide a visual reference nearby pilots, warning the pilot to take appropriate measures to avoid the collision.

 

Such systems installed in critical areas of aircraft aerodynamic surface, complex structure, space is relatively tight, you need to consider the local shape, the installation space, mechanical interface, weight and other factors. Traditional external lighting techniques often used bulky, short life, high cost of halogen lamps, the rapid development of solid-state light source technology to improve the exterior lighting brings opportunity.

 

Situation and Difficulties

 

Means a solid state light source emitting diode (LED), organic light emitting diode (OLED), polymer light emitting diodes (PLED) and other semiconductor electroluminescent (EL) light source technology, with high luminous efficiency, good color, color adjustable small emitting area easy to integrate, long life and other advantages, including LED light efficiency is currently the highest, most mature state of the art solid state light sources.

 

Currently civil aircraft external lighting has been extensive use of LED, navigation lights, exploration Ice, lights, red anti-collision lights and other LED products have matured. However, LED light source in a mature aviation lighting products in a manner similar to traditional lighting applications, but replaced the traditional light source LED, do not take full advantage of LED's characteristics and advantages. In addition, some onboard power lighting equipment yet to adopt LED light source, such as landing lights, taxi lights, turn the runway lights, white anti-collision lights.

 

Existing landing lights, taxi lights, cornering lights runway HID lamps commonly used as the light source, the use of high-pressure gas discharge light, can meet the lighting needs of high brightness, high illumination, and has good anti-vibration performance. But its life expectancy is only about 4 000 h, need frequent replacement. In addition, light starter a long time, usually after starting 15 min in order to achieve a stable light output. As a result of the high voltage power supply, light and power cables have a certain security risk, high-current discharge moment within the cable also increases the risk of fuel system, and electromagnetic interference generated greater need to take strict measures to shield. Since the power efficiency of the light source is only about 40%, most of the energy is converted to thermal radiation and ultraviolet radiation, the lamp of high operating temperature, and other equipment and structures Effect mounting region.

 

White anti-collision lights usually xenon lamp as a light source, a xenon lamp life of only 2 000 ~ 3 000 h, maintaining high frequencies. Working as a gas discharge lamp pulse, high ignition voltage, working current xenon lamp drive circuit demanding. Often with large capacity electrolytic capacitor and transformer circuits, high cost, electrolytic capacitor life is only about 4 000 h, need frequent replacement. Instantaneous high-current gas discharge mechanism due to electromagnetic interference also brought fuel dangerous problems.

 

In addition, some exterior lighting equipment installed in the pneumatic sensitive area, landing lights, cornering lights runway is usually installed in the wing wing root, affected slats, installation space is tight, or so white anti-collision lights, navigation lights mounted on the left and right wing slightly winglets, winglets for composite materials, the winglet winglet surface openings affect the strength of the local need for strengthening the structure, increasing the structural weight and cost. With the wide application of supercritical wing, leading edge thickness decreased, increased lighting installation difficulty, to achieve structural costly installation required. In addition, since the wing during flight will be deformed, if the structural support rigidity is not high enough, the stress generated in the shade, causing internal cracks, or even damage, is not conducive to the safety of aircraft flying.

 

Application Advantages

 

In aircraft lighting, LED technology has great prospect, LED lighting technology helps improve the overall performance of the aircraft lighting system. In the cockpit lighting, LED light guide plate, dome light / floodlight can provide an expert - Machine efficacy of display devices and low-fatigue visual environment; the cabin lighting, LED flood lights, reading lights, etc., may increase the cabin comfort, features an LED-based color-tunable illumination scenarios can be realized more situational cabin lighting, provide passengers with a pleasant opportunity environment; external lighting, LED light source can improve the efficiency, reliability, security, comfortable, effective visual information for pilots; use LED light source in emergency lighting can save power consumption, improve the life and reliability of the system. Given the inherent advantages of LED technology, and the current performance gap related products, civilian aircraft external lighting is bound to full adoption of LED products.

 

Currently civil aircraft external lighting has been extensive use of LED, navigation lights, exploration Ice, lights, red anti-collision lights and other LED products have matured, and used in the B787, A350 and other advanced models. However, LED lighting products in aviation applications mature manner similar to the traditional lamp light source, just replace the light source is LED, do not take full advantage of LED's characteristics and advantages.

 

In wingtip navigation lights, anti-collision lights of R & D, Goodrich company already has a mature product navigation lights and anti-collision lights in the development of LED products, are independent of the equipment, installation interfaces similar to traditional lamps.

Landing lights, taxi lights, cornering lights, and other high-power runway, research and development of high-intensity device, the world's leading supplier of lighting equipment have been carried out related research and development, and introduced the corresponding LED products. 2009, Honeywell introduced its modular LED landing lights, using a combination of the LED array.

 

Modular LED landing lights in life, reliability, maintenance and other aspects are much better than the existing HID technology, specific performance comparison shown in Table 1 below. By contrast parameter table that LED-based lighting equipment in working life, flight cycles, start time, strobe work, respect line safety and reliability have been greatly improved.

 

Development Trend of solid-state lighting device has a power increases, the light effect gradually improved, gradually increase the power efficiency characteristics. On the high-power solid-state lighting device design method, application of integrated modular design technology more widely, to further improve the reliability and maintenance of the equipment.

 

In the prior civil aircraft lighting systems, high-power landing lights, taxi lights, runway turn lights, white anti-collision lights, were not using solid state light sources. Exterior lighting system performance directly affects the security of the pilot visual ability and aircraft airworthiness regulations and relevant industry standards for landing lights, anti-collision lights have clear performance requirements. While the prior art to meet the performance requirements of Airworthiness to some extent, the use of conventional light sources to the system-level integration brought many problems. As stated above, the use of conventional light sources lead to a short life of the system, installation space is tight, maintain high frequency, electromagnetic compatibility is poor, long time starter.

 

Solid-state lighting technology to improve system performance and integration benefits brought an opportunity, you can see from the survey results, the major supplier of aviation lighting system has been fully transferred to the high-power solid-state light source application technology, and the development of the fledgling power combination type LED landing lights. While this technique has not been applied to mature models, based on the inherent advantages and technological development potential of solid state light source, and a significant advantage in system integration, it is expected that the next generation of technology will be widely used on civil aircraft.

 

Conclusion

 

According to the current situation and development trend of domestic and foreign technology, high-power solid-state light source lighting technology can significantly improve the overall performance of the machine and outdoor lighting. Integrated landing lights, anti-collision lights tip navigation technology has great compared to the traditional performance advantages, can effectively solve the interface definition of prior art, maintenance and installation issues. Application of solid-state lighting technology will greatly enhance the wing root landing lights, anti-collision lights tip navigation ease of integration, according to the characteristics of the aircraft shape, optimize local arrangement effectively reduce the impact on the shape, structure and the like. Solid-state lighting technology integrated design will help improve the overall performance and the overall performance of aircraft systems, reduce operating and maintenance costs.

 

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