Research And Design Of LED Light Source For Military Vehicle-borne

In recent years, the semiconductor illumination technology developed rapidly. LED (Light-emitting diode) , as the core product in the lighting field, occupies a pivotal position. LED light sources are the fourth generation light sources, following the incandescent, fluorescent and gas discharge lamps. Since the 1990s, the"green light"policy has been proposed, LED light development also causes for concern. LED is a semiconductor device, which can light and has the electrical characteristics of the diodes. LED light source is one of the typical green light sources. It has nine fantastic advantages, namely, high luminescence efficiency, high lighting quality, low energy consumption, long life, reliability and durability, application flexibility, security, environmental protection, and short response time. Therefore, many domestic and foreign study groups are interested in the LED technology, which also accelerate the commercialization of LED light sources. LED can be widely used in the areas of display, traffic signals, automotive lighting, architectural decoration and so on. At the same time, many countries have begun to study the military aspects of LED lighting applications, to prepare the upper hand in military equipment.LED was used in cars as early as in the mid-1980s, mainly in the high brake lights. Currently, high-power LED has been extensively used for automotive lighting, accounting for about 18% of LED lighting market.In order to satisfy the needs of modern war, the development of military equipment of all kinds has tended to be flexible. In accordance with GJB, the equipment in military vehicles must pass the rigorous tests of high and low temperature, vibration, shock and other indicators. However, the civilian lighting lamps are still used as the light source of military vehicle-borne, but they can't meet the need of GJB, because they are easy to damage in strong shock and vibration. To improve the modernization level of our weaponry and meet the realistic operational requirements, it's necessary to research and develop the light emitting diodes for military vehicle-borne. In this article, we aimed to increase the characteristics and ensure the reliability of interior illumination in military vehicles, a white light source based on light emitting diodes was designed and fabricated.The light source designed for military vehicles was composed of PC lampshade, LED light source, aluminum circuit board and aluminum alloy shell. Polycarbonate was used as the raw material of PC lampshade. It is an amorphous, odorless, non-toxic, highly transparent and colorless or slightly yellow engineering thermoplastic with excellent mechanical properties. Aluminum circuit board was used to better resist against the shock and vibration and improve the properties of heat dissipation, which would make the light source more durable. During the production progress, the home-made light emitting diodes with low color temperature were used in this light source. The emitting spectra were measured. Through the mechanical design, the volume of the light source was reduced evidently. Soft seal was used to realize the dustproof, waterproof and shockproof. A series of measures were employed to improve the characteristic of the light source on voltage fluctuation. Cold resistance and heat resistance were evaluated. To meet the requirement of the vehicle power supply (DC24V), the light source used six high-power LED bulbs (1W), connecting in series. LED was fixed on the aluminum circuit board, while limiting the resistance in the series circuit. The voltage of each high-power LED bulb is 3.2V. The remaining voltage distributed on the limiting resistance. The operating current is 300mA. For LED's pn junction, the simplest current limiting scheme, which was highly reliable and easy to maintain, was adopted. Considering the voltage dropped across the circuit resistance, A 18? external current limiting resistance was joined in the circuit, which greatly enhanced the light source's ability to resist against voltage fluctuation.Finally, compared with the traditional light source, LED source, only 17mm in thickness, was reduced by 83mm, which greatly expanded the operating space in vehicle. Tolerances on moisture, dust and vibration were also meliorated. In the mode of DC voltage drive, when the voltage fluctuating±1V, the current changed only±100 mA, the LED light source could work normally. At the same time, the new light source based on LED possesses the characteristics of thinner size and good resistance against heat/cold, moisture, dust and vibration. It is a competent light source for interior illumination of military vehicles.In the next generation of LED designed for military vehicles, we will further consider its application in the war. Adopting external battery is one of the most important aspects, which will make the light source work properly after the cessation of the whole vehicle power. View of the small compartments and the soldiers in a high state of tension in the vehicle cabin, we will design other colors or color changing LED light sources, to facilitate their adaptation to the dangerous environment of war.