Regarding car lights, we generally pay attention to the number of lumens and the power. It is generally believed that the higher the "lumen value", the brighter the lights! But for LED lights, you can't just refer to the lumen value. The so-called lumen is a physical unit that describes the luminous flux, which is explained by physics as a candle (cd, candela, luminous intensity unit, equivalent to the luminous intensity of an ordinary candle), in a solid angle (a unit circle with a radius of 1 meter). On the sphere, the angle represented by the spherical cone corresponding to the spherical crown of 1 square meter, which corresponds to the central angle of the mid-section (about 65°), produces the total emitted luminous flux.
In order to be more intuitive, we will use the LED flashlight to do a simple experiment. The flashlight is closest to life and can most directly reflect the problem.
From the above four pictures, we can see that the same flashlight has the same light source, but the reflector is blocked, so there is such a big difference, which shows that the brightness of the flashlight is not only related to the brightness of the light source itself, but also is inseparable from the reflector. Relationship. Therefore, the brightness of the headlights cannot be evaluated only by lumens. For the headlights, we should use a more realistic "light intensity" to judge,
Light intensity refers to the energy of visible light received per unit area, referred to as illuminance, and the unit is Lux (Lux or Lx). A physical term used to indicate the intensity of light and the amount of light on the surface area of an object.
The measurement method of illuminance is also relatively simple and crude. After loading, it can be measured only by the illuminometer. The lumens can only prove the data of the headlight itself before the car is installed. The light after the car needs to be concentrated and refracted by the reflector. If the focus is not right, if the light cannot be fully refracted, no matter how high the "lumen" is no point.
(National Standard Light Pattern Chart for Vehicle Lamps)
The car lights also need to emit light through the light source and then be refracted by the reflector cup. The difference from the flashlight is that the light spot of the car light is not circular like the flashlight. The requirements of the car lights are strict and complex, for driving safety and Considering the safety of pedestrians, a standard has been established for the angle and range of light, and this standard is called "light type".
The "light type" (low beam) of the headlights should be low on the left and high on the right, because the left side of domestic cars is the driver's position. In order to avoid dazzling lights and improve driving safety when the two cars meet each other during night driving. The light spot on the right is high. For the driver of the left-hand drive car, the right side of the vehicle has a relatively poor line of sight and needs a wider field of vision. Try to be able to illuminate the pavement, intersection and other road conditions with a larger area on the right, if possible. Take action ahead of time. (If it is a right-hand drive car, the light pattern is opposite)
Advantages of LED lights
1. LED light products are low-voltage starting, and the safety factor is relatively high;
2. LED light products start instantly, which is more in line with the needs of human vehicles;
3. Energy saving and environmental protection, with obvious advantages for the development of new energy vehicles in the future trend;
4. With the continuous optimization and improvement of the upstream high-power LED lamp bead industry chain, the cost-effective advantage of LED lights will be further revealed.
5. The plasticity of LED light source is relatively strong, which is very suitable for the future personalized consumption trend.
Post time: Aug-23-2022
