Design and analysis of price advantage, reason and system of LED automotive headlamp

The cost and complexity of the adoption of LED htacl light beam, but the matrix control function will bring the technology to the forefront.

Although there are some shining examples of LED applications in automotive headlamp, but the rate is still not as solid state lighting (SSL) as fast growth. A kind of unique design challenges in automotive applications, but the cost is still relatively high. However, the LED will increase the unique function to the headlights. In this paper, we will introduce the design can produce a powerful headlamp system.

Between general lighting and automotive lighting, you can compare. We all remember the traditional incandescent light bulbs. At the end of 2013, most American families usually use 40W and 60W incandescent bulb was banned in the United States manufactured or imported; but, even so, they still can buy. It should also be noted that in 2012, 75W and 100W lighting has been eliminated.

The reason they are eliminated, the U.S. Environmental Protection Agency (EPA) to better electro-optical output efficiency. The main reason is due to the transition of about 14% residential lighting accounts for power consumption (source: U.S. Energy Information Administration), helps to reduce the power consumption. The solid LED lamp requires only about 1/8 of the electricity can be produced the same amount of lumen output, so LED lights into our modern world.

From incandescent bulbs to the evolution of solid state electronic lamp and development of automobile industry of vehicle lighting happening now is very similar. Although the red LED lights have been used in the tail in more than 10 years, but the inside of the car and to change the lighting system before the adoption of LED has made significant progress. For example, more than 70% internal lights and more than 45% meter display backlight using LED lamp. In contrast, now more than 55% of the daytime driving lights (DRL) and about 5% headlights with LED lights. Ironically, although the headlights (the distant lights, fog lights) represents the biggest opportunity, but they are the least permeability! One of the main reasons is that carmakers cost is too high, consumers are reluctant to pay.

The car headlights

Before we discuss the reasons for the low rate lighting, it is necessary to know why a lot of drivers or original equipment manufacturers prefer LED lighting products. These include but not limited to the following:

The performance and design flexibility. LED because of its shape factors provide design flexibility, provides a wide dimming function. Please remember, the human eye deviation in light output is very sensitive.

Energy saving and emission reduction and low carbon dioxide emissions. LED not only has better power efficiency, thereby reducing the need for the power supply of energy, but also has a longer life cycle.

Cost. This may seem counterintuitive, but in non headlight applications, continuous cost reduction, improve the durability and quality makes LED become a new standard for terminal customer value.

Regulations Many of the provisions of the government's clear DRL and headlight and other lighting applications, increasing the demand for LED lighting.

In the LED automotive exterior lighting applications, Audi is generally considered to be a leader, anyone not surprised. Anyone who saw Audi's famous "eyebrow" daytime running lights in the rear-view mirror, they are very prominent. In addition, Audi for the first time in the 2004 Audi R8 first used LED headlamps. In addition, Audi is famous is able to guide the beam (Figure 1 you can see an example of beam steering) matrix headlights.

Figure 1. illustrates the matrix LED headlights to light.

So why not LED headlamps and other forms of automotive LED lighting so popular? The answer is of course cost. In the headlight, alternative LED is incandescent lamp, halogen lamp or high density discharge (HID) xenon lamp. Comparable LED may cost is 100% higher than that of halogen headlights, HID xenon lamp 1.5 times higher.

LED where appropriate?

In general, the light, LED headlight between halogen lamps and HID lamps, but provides more focused radiation LED headlights, and can also be controlled to produce different shapes. In addition, because of its small size, LED can be a very good operation, car manufacturers can produce a variety of shapes and components, perfect matching model.

Although don't emit heat LED light, but when the electric current passes through, produce a certain amount of the transmitter at the bottom of the heat, so the components of adjacent and connecting cables caused by the potential risks. Therefore, LED headlamp need cooling system, such as a radiator or fan, to prevent the melting. In addition, the cooling system in the engine compartment, for some other systems to maintain the proper temperature, the engine is not a cool area. This is another reason why LED headlights in the vehicle to design and implementation, therefore more expensive than HID lamp.

The only choice of LED may not be the next generation of headlights. The United States trade news in a recent article said, Audi launched an optional laser beam in its high performance in R8. This system is very good, not the light to the front vehicle, so the headlights can stay open and self adjustment, even if there are 8 cars in front of it. Compared with the LED laser beam, the spotlight of Audi along the road (500 feet) projecting beams in the far distance of two times, thus allowing the driver to see farther distance.

Using IC to promote LED

Now we have to solve the challenges of LED drive. Incandescent lamps produce light output, the premise is the current through the filament; while LED is not the same, LED needs to be designed