LED new direction in automotive applications

Since the early 20 century in 70 began manufacturing LED, but in recent years, the development speed of the technology has been improved significantly. The maximum available LED brightness has increased by several orders of magnitude, from the beginning of the 20 century 70 in early 20mA when 0.01 lumens, achieve the 1 lumens and above. With these improvements, the target application LED has also been greatly widened. Because of high luminosity 0.3 lumens, LED actually substitute products become incandescent lamp. They also have many advantages, one of the important advantages is that they are very reliable. In short, the LED life will be far more than the use of any system itself. This feature is most suitable for the car system in the automobile system, high reliability can ensure safety and avoid costly repairs. Therefore, the automotive industry has been relatively quickly turned in any feasible cases using LED technology, in fact, by virtue of the special requirements of the automotive industry is to further promote innovation in the field of LED. LED brightness in 1970 years with the development of 1995 years, LED gradually developed to provide a higher level of brightness. But since the 20 century 90 in the mid-1990s, with more innovative blue and white LED and these devices mean brightness, innovation has been accelerated step. Improved LED brightness is mainly attributed to the floor material progress. From the first p GaAs (GaAs) products, 20 in the late 70 century the industry turned to the use of nitrogen doped GaAsP and GaP, and made the first yellow and green LED, and then in the 20 century 90 in the early 1990s by single and double opposite sex GaAlAs achieved more than 0.1 luminosity lumens. Since the early 20 century 90 in various combinations of indium and gallium has a variety of colors as newer and more bright (including blue) of the LED floor. Despite the progress, but there are still many problems, such as the floor often excessive absorption produced by the LED light. Many methods have been adopted to avoid this problem. Lumiled by using transparent AlInGaP floor, to overcome this problem. Another method is to add Bragg reflective layer on the floor. This method brightness is two times the LED brightness light absorbing plate, but any light to 90 degrees from both will disappear. Vishay has been using OMA (organic mirror adhesion) technology improved the solution. In this technique, the mirror is covered in silicon plate. Exposure to all the light on the mirror from the device is reflected, in order to achieve the same level of brightness, realize and use method or transparent plate, its brightness is four times higher than the standard LED. LED LED efficiency not only bright; they also need to work effectively. This means that not only the minimum loss of electrical energy into light, but also to control the operation of the device in the current generated by the thermal effect. The great challenge LED is their junction temperature (when applied more current when the junction temperature rises) will directly affect the wavelength of light they produce. Therefore, increasing the forward current can only change the color of the device, but not make it brighter. Therefore, it is necessary to achieve a higher brightness of the chip and packaging technology with less current. Vishay has been using a series of ultra-thin PLCC package to solve the problem, the cooling efficiency of these packages is very high, so it can reduce the current caused by higher color change. This special PLCC-3 compatible with the industry standard PLCC-4 implementation liner, and has a large metal surface diffusion heat, we can use the standard tablet core and realize super bright LED 50mA by forward current power supply. The new device used in the TLMx320x series PLCC-3 package to 270k/W rated low thermal resistance, these devices can be driven by a higher current, can achieve brightness than the PLCC-2 package similar twice as high as LED. In the car market LED LED is successfully replace the incandescent lamp in the car, for automotive interior and exterior lighting. The equipment failure rate (the maximum failure rate per 1000 000 for 0.1) and the brightness and color must meet strict quality requirements. When multiple LED assembled together and used for dashboard lighting, instrument panel or entertainment system control, the consistency of the color and brightness of the lighting brightness is obviously very important; the area still needs to be consistent, and there is no shadow. But in the automobile system, due to the current LED has become a part of the color scheme of the car interior, and is also an important part of the manufacturers how to build brands, and therefore beyond the purely aesthetic requirements on the consistency requirements. This means that LED and specified for automobile manufacturing and the wavelength, the variation is only limited to the naked eye can not feel the degree, generally only a few nanometers. Car manufacturers want to build their own brand products, the use of unique LED color in fact, this desire has been produced to provide "on-demand color" senior professional skills requirements, which requires increasingly complex LED product, in these products, LED tablet core requires a combination of different colors in the same package. Due to the naked eye on color perception depends on the intensity of the color, it has its own design challenges, in the same chromatographic intensity, more high-end color (such as yellow) often cover the lower end of the color (such as blue). For example, to create a pure green LED, blue light intensity components must be roughly two times the intensity of light yellow element.