Do you need a lens for the led headlights?
A sign of judging the quality of LED lights is whether there is a condensing lens. if yes, it must have a good light shape, but if not, it can be astigmatic in poor light shape and so don’t buy it”. We often see a variety of tips on the Internet, but sometimes it is difficult for those who buy LED lights to identify the true from the false. The tip about lens I just mentioned is one of these.
Do LED lights have to be equipped with condenser lens, and if yes, what are the advantages and disadvantages? Today we’ll talk about this topic.
It starts with halogen lamp and xenon lamp, the predecessors of LED lamp.
Halogen lamp is an evolution of incandescent lamp that is able to stimulate heat radiation by electrifying tungsten wire in the lamp. The difference is that halogen gas like iodine or bromine will be injected into the bulb, so that the sublimated tungsten reacts with the halogen at a high temperature and then the cooled tungsten refreezes on the tungsten wire to form a balanced cycle, thereby avoiding premature breakage of tungsten wire. In this way, the bulb will live longer with higher brightness.
Xenon lamp, also known as high intensity discharge (HID), means that a mixture of inert gases including xenon activates inert gases in the quartz tube and makes them emit arc lights through 2300V high-voltage current. Different from the halogen lamp, such lamp can not rely on filament thermal radiation but generate arc lights, so as to obtain higher color temperature and brightness at lower power.
Condensing lens is flourishing with the popularity of xenon lamp.
Solution to the problem that it does not concentrate lights
People who keep an eye on PAVEDGE Lighting Lecture may remember the three elements of LED lights, that is, brightness, condensed light and installation. It is necessary to achieve satisfactory brightness under the condition of low output power as far as possible; it must gather lights and the light emitted is in good shape like paving; it must be easy to install and to dissipate heat. Actually, these three elements are also suitable for other lights.
Xenon lamp has technical advantages that halogen lamp can not compare with, but it also has a huge problem, that is, not concentrating light. As I said in the PAVEDGE Lighting Lecture 1, the point source light is best at concentrating lights, because it is 360-degree light and can effectively form a good shape through the lamp bowl. However, the planar source light is not good at gathering lights, so that PAVEDGE has to thin the gap between the beads through various techniques to make it as similar as possible to the spot source light. Xenon lamp is more difficult to gather lights than LED lamp, because it emits arc light after electrifying high-voltage inert gases in the quartz tube, which is similar to lightning. This light is more irregular and wilfully shines as it like!
In order to solve the problem that the xenon lamp can not gather lights, those with power in science and technology have specially configured a lens, which focuses randomly scattered lights, in the front of the xenon lamp, thus bringing out better light shape and directivity. Finally, we get the light shape that can be used at night.
Advantages and disadvantages of lenses
Many owners think that the lensed lamp is chic enough, commonly known as the “bull eye”, and it looks refreshing. But every thing has both sides.
First of all, the lens is a convex lens like half a glass ball, but when the light passes through it, the loss of light will be caused due to its internal structure. Compared with the lamp without lens, no matter what brand of the lamp you are using, it usually loses about 30% of brightness. And after a long time, the lens will be generally full of dust. The laboratory testing shows that the old lens can only reach 40% of the original brightness! And it’s hard to clean up.
Second, its installation cost is currently not cheap on the market, and it may be regarded as illegal refit by traffic police in some areas if the lamp is not from the original factory.
Third, LED lamp has a different luminous pattern from xenon lamp. Based on excellent industrial design (such as PAVEDGE series), it largely emits dot-shaped lights and depends on the lamp bowl to well ensure the parallel emission and uniform coverage of lights.
Fourth, there is almost no light loss in the lamp bowl without lens, so LED lamp is able to reach the brightness of the greatest value in the lamp bowl.
Fifth, since it is a convex lens, it inevitably has a focusing effect, which may burn the interior of the lamp assembly, such as decorative sheets and other materials.
The burn is where the red arrow points
There is nothing wrong with the condensing lens if you are using the xenon lamp; but if you are using the LED lamp, don’t follow the trend for a change, especially in the case that your LED lamp already has a good light shape. There is no need to install the “bull eye” to avoid waste, light loss and other unsafe factors.
Many car fans are very keen on the tangent line from the lens and trust everything based on the tangent. But as mentioned earlier, it is the xenon lamp that gives rise to the lens and so there is a lens tangent. In fact, the purpose of the lamp is to pave the road, not just for the tangent line, and it can still pave the road well even without a perfect tangent line. Therefore, do not follow cart-before-horse thinking that is to blindly pursue the tangent. The lens must be used in the xenon lamp, otherwise it will not gather lights, at the same time, flash to blind the car face to face. However, the era of xenon lamp has been nearing its ends and the LED era is the future, so the xenon lamp lens refitting industry is bound to fade away. The principle of LED lighting is close to that of halogen lamp. At this time, the use of lens will actually have a great loss of light (it doesn’t matter for the matrix to use lens because of N LEDs). And the LED lights themselves are perfectly capable of focusing lights, so it doesn’t make much sense to refit the lens.
If the original car is equipped with a lamp bowl, change into the LED light bulb directly. The choice of a LED lamp gathering lights better will make the lamp brightness and paving not weaker than that of the xenon lamp with modified lens. But if the original car is equipped with a lens, it is necessary to select a special lens product, because its lighting principle is different from the lamp bowl’s. For LED used in the ordinary reflecting lamp bowl, its effect will be greatly reduced and there will be a shadow. PAVEDGE’s special lens can solve the problem of lens brightness and light shape.