Among the common lamps on the market, they are basically divided into two groups. The domestic lamps occupy ultra-low price, and the imported lamps become synonymous with burning packages. The quality difference between domestically produced lamps and imported lamps is mainly reflected in the following three aspects.

Light type accuracy

Most of the domestic lamp reflectors are not shaped by computer-aided design. Instead, they use a model of overturning, which directly pirates from the molded product. For more detailed things, few manufacturers really go deep into the research. For headlights, a final light pattern depends not only on the design of the reflector bowl, but also on the lens section (clear glass or polyester cover on the front of the headlights). It is completely achievable to completely imitate the two, but when it comes to the refractive index of the lens and the non-dot light source provided by the halogen filament, the accuracy of the light type is difficult to be easily copied.

We know that the refractive index affects the direction of light passing through the lens; and the distance between the lens and the reflector bowl also directly affects the accuracy of the direction of the outgoing light. The latter is easy to replicate, but the refractive index of the lens depends on the material itself, which is difficult to achieve complete reproduction without the analysis of precision instruments.

Moreover, for the halogen light source we use nowadays, it is not an ideal point source itself. As we all know, the filament has a certain length, and it is impossible to use the simple high school physics common sense to deal with the deflection of this light source. If the high school physics common sense can be directly used directly, we will buy a spherical glass shell by ourselves. After cutting into two halves, the inner surface is coated with a reflective film, and the lamp is placed at the position of the center of the ball, which can be used as a spotlight. It is.

In order to accurately control the final light pattern of the non-dot light source, it must rely on the professional auxiliary design software. After the light path calculation is performed by the software on the filament point by point, the light emitted from different positions of the filament at the light drop point is superimposed at this point. In order to get the final light design (this is why many people find HID after installation, the reason for the light divergence, the light point of the HID light source and the halogen light can not completely coincide, usually it is a curved fold line, similar to lightning same). Even when you use a bulb that is produced in a non-standard format, it will cause a deviation between the final exit light pattern and the design light pattern. A good luminaire will allow you to get the most out of your design, while only a small amount of light falls outside the design area.

High temperature resistance and oxidation resistance of reflective bowl coating

The most intuitive feeling of the coating of the reflective bowl is the reflectivity. Usually, the newly purchased lights can achieve a good reflection effect. Only in the surface of the reflectors with poor coating quality, a large number of bubbles, impurities, protrusions and other visual quality problems can be found. This is not always seen on normal quality products, as this is a defective product for general quality control systems. However, what really makes us distinguish between quality products and by-products is the inherent quality of the reflective film.

In order to save production costs and improve reflection efficiency, modern coating technology usually uses an aluminum film, and aluminum itself is easily oxidized by long-term exposure to air to form a non-reflective aluminum oxide layer; at the same time, in order to enable the coating to be reflective with the bowl metal The substrate is firmly bonded and is usually made of a polymer material. When the polymer material is irradiated with ultraviolet light, it will age rapidly, resulting in whitening of the reflective bowl. However, this does not mean that our existing reflective bowl will be exposed to the sun and cause aging. That point of ultraviolet light is only drizzle for polymer materials. The source of ultraviolet radiation that really makes it aging quickly is precisely the light source that we provide illumination for the lamps. --light bulb. The light source we use now is not a single wavelength, its wavelength is continuous, but we can't see the infrared and ultraviolet light in the naked eye. Therefore, many large manufacturers produce light sources with special indication: UVcut.

Another intrinsic quality of the coating is manifested in its high temperature resistance (which is of course related to the thermal design of the luminaire itself). The halogen lamps we use are thermoluminescent. The normal working temperature of the filaments is 2000 degrees Celsius. In the confined space of the lamps, such heat sources can heat the air inside the lamps to 150 degrees or more, and the infrared part of the continuous light waves is also It needs to be reflected by the coating (reflectivity is impossible to reach 100%), and the three heat transfer modes of heat conduction, convection and radiation are heating the coating. The continuous heating for a long time will make Li Gui and Li Wei appear in the original shape. The domestic fog lamp products I have used, no one product has been kept on the base of its reflective bowl after 10 hours of driving at night, and it is firmly attached, and only a small area of ​​foaming occurs. Good quality products.

Impact resistance, transmittance and temperature resistance of the lens

The so-called lens is the transparent mask in front of the lamp, usually made of two types of materials: glass and polyester. The biggest advantage of polyester products is its impact resistance. The stone shattered glass lampshade and windshield rolled up by the front tires on the gravel road is probably the heartache of many car lovers, and the polyester products are encountered. In this case, usually only a small white pockmark is left, or several extremely fine cracks of the turtle appear, without affecting the use of the entire lamp.

In addition, the ability of polyester materials to withstand sudden changes in temperature is also unattainable by glass materials. After all, the brittleness of glass is much higher than that of polyester. When we drive the lamp through a rainy and foggy road, if the quality of the glass is not good, If you wipe the lamp surface with a simple wet wipe, it will bring endless troubles to your journey, because the lamp will burst into several pieces. In terms of light transmittance, the glass material is superior to the polyester material in durability. If the quality of the polyester material is not good, it will age in a short period of time (half to one year), at which time the lens color becomes yellow and accompanied. There is whitening, and the glass is not affected by external conditions such as ultraviolet rays, and continues to maintain its initial transparency. In addition, students who pay attention to the light and light type need to pay attention to it. It is not the same size of the glass and polyester lens that can be directly replaced, because even if the two patterns are completely consistent, the difference in refractive index between the two materials will cause the light type to change.

Edit: Pony