LED For the consumer, has been widely used in the car, depending on the performance requirements to select the appropriate LED products, LED compared to traditional light sources in addition to the appearance different, the performance output and optical output is also not the same optical design and thermal design is different from the traditional lighting of the design concept is applied to the headlamp will face. However, because of its different from the characteristics of traditional light sources, and to successfully integrate with the body to overcome the technical problems for the models to create a new design concept.
LED has been widely used in interior lighting or instructions with light, we can see from Figure 1, from the dashboard of the car lights, car dome light, make-up lights, welcome light to the vehicle’s tail lights, front and rear turn signals. down lights, third brake lights, and other related applications can see the LED.
From the historical point of view of LED applications, as early as 1992 when the LED used in the precedent for the third brake light; 2000 is further applied to taillights, turn signals and brake lights; take the lead in the 2002 Audi A8 LED light source placed in front lamps as daytime running lights, turn on the imagination of designers and engineers in the front lamps. Can be seen on the many international auto show concept car, the LED lights as a headlight source.
LED inherent small size advantage, applied to the front lamps may reduce the volume of the entire group of lamps, and further to give up valuable space for engines and other related equipment existing halogen bulb or discharge lamp design lamps with a total length 300mm, in concept car design, LED lighting is only 125mm long. By the advantages of small size, with the design of a variety of different design, and then for the body shape to create a different visual perception, escape from the circular design of the traditional lamp.
Different as the application level, the depot also use the LED light source package corresponding to the different environmental requirements, according to the different needs of brightness can be simply divided into two directions with lighting and projection in three different Indication light source visible in the third brake light, rear light clusters (taillights, brake lights, turn signals, etc.), side lights, low lumens light output, low power required of about 70mW ~ 200mW, the heat generated package less affected body, so the package will ignore the impact of this heat, and direct use of the resin material coated to the package as a whole, the resin with low thermal conductivity (W / mK), so its thermal resistance heat is not easy to rise to 50 ~ 200K / W; illumination light source package power relative to the higher brightness of the daytime running lights, fog lights, can be applied to the directions of the light source used class of products, can also be used, before the direction of light, but also because of the loss of power increase (power about 1 ~ 5W), the thermal part can not, as indication light does not consider heat issues still need to use a piece of metal will heat export, in addition to the resin material package in order to maintain the optical efficiency , maintained at below 15K / W thermal resistance; and projection light source, light package brightness needs, the main lighting system (far lights, low beam, fog lights, etc.) before their application, and its single package required 4W or more, while less than 5K / W thermal resistance on the need to ensure that the cooling capacity to maintain the high temperatures of the engine room, and maintain the efficiency of the light output in the range of available
Different level, the total brightness needs about 80 lumens of brightness to the interior lighting is generally used in surface mount (SMT) package, single package about 2 lumens of output, efficiency up to 15 ~~ 20lm / W. About 30lm the brightness of the third brake light, is generally used in the artillery-type package structure (φ = 5mm), the brightness of the single package about 4 lumens, the efficiency of up to 20 ~~ 40lm / W.