Does the LED optical lens act as reflection or refraction?
LED lighting systems; non imaging optics; design; lenses; aspheric mirrors; refracting platesLED light source has many advantages compared with the traditional light source, which has become the consensus, but the LED chip has the advantages of small size, compact structure, the luminous area is relatively smaller, it is a 180 degree angle from the Lambertian source of light, the light intensity distribution and is proportional to the cosine of the angle, which is issued by the LED light source the light in the illuminated surface of the illumination with the exit angle increases rapidly. The attenuation characteristic of the light source is obviously very difficult to meet the actual needs of outdoor lighting purposes. Therefore LED in outdoor lighting applications, we must according to different situations and needs, the two optical design according to the characteristics of LED light source thus, issued by the LED light chip shaping and change, especially the intensity distribution. The two optical design process that actually belongs to the category of non imaging optical design.
Non imaging optical design in twentieth Century 30s, only is to try to improve some properties of optical products practice, until 70s, non imaging optical design theory has gradually become a system. Compared with the design of optical imaging system about source of information transmission, non imaging optical system design is concerned with the use of light energy and light distribution control. Due to the structure of non imaging optical system is simple, high energy utilization rate, therefore caused widespread concern in the design of LED lighting system, currently has a hot research, especially for LED lighting system in the illuminated surface to achieve the required light distribution, non imaging optical design can play a decisive the role of the key.
In the non imaging optical design of LED lighting system, optical elements are basic lens, aspherical mirror and refractive lens plate. The light emitted from the point light source can make the convergence or divergence, to change the size of the beam angle, thereby changing the illuminated surface lighting product and illumination purposes. The aspherical reflector shape is usually two rotating surface, its working principle and lens and reflector lens is completely different, with the refraction principle, the mirror is reflected or the principle of total reflection, the aperture angle is below 40 degrees, rather than above the spherical reflector aperture angle up to 130 degrees, i.e. it can greatly enhance the ability to collect light. The main function is to change the light refraction in the exit direction or change the beam in a particular direction angle, in fact it is a common and familiar LED light system abroad Around the plastic panel, the plastic panel according to structure classification, main tooth refraction plate, trapezoid refractive plates and cylindrical refracting plate. Each tooth refracting plate is equivalent to the surface of a wedge lens, refraction effect can make the light deflection, but will not change the beam angle of the main beam to change exit direction. The equivalent of trapezoidal refracting plate of flat glass and a wedge lens body, it can make a beam of light into three directions, and the three direction of the beam intensity ratio is the ratio of its area of control plane and inclined plane. The cylindrical refracting plate is also known as the compound eye lens, which is composed of a a series of cylinders, each cylinder is equivalent to a cylindrical lens in the generatrix direction, the direction of the incident light to maintain the original, while in the non cylindrical generatrix direction, the role of the lens in all directions are convergence or divergence, so as to realize the beam spread angle For the purpose of
