The application of non imaging optics in the design of LED lighting system

LED lighting system in the design, we should first determine the design requirements and conditions, such as material, structure, light source lighting system distribution, in accordance with the relevant requirements to determine which belongs to what kind of optical design, 2D system, rotational symmetry system or 3D system, and then according to the optical design of the specific choice of different design methods. While the size of the LED chip size can generally be ignored, while further simplifying the design steps can be used to point light source design.

Design of optical coupling system

Under normal circumstances, there is a need for a collimated projection of the surface light source in the projection lamp, projector light source, and night lighting system. In particular, it is necessary to obtain a relatively small projection angle of the surface light source, when the light is projected onto the object, the diffuse reflection will be captured by the human eye. We can see that the LED chip is an approximate Lambertian light source, its divergence angle is relatively large, and the far field distribution can not meet the requirements. At the same time, the light output from a single power LED chip can not meet the actual requirements of the brightness. To this end, collimating LED optical system not only to achieve the LED chip light emitted in a larger area of the collimated output, but also must be easy to expand. In order to realize collimating light source, two optical elements can be used in some designs, and the so-called secondary optical element, which is used in conjunction with the packaged LED, is used to realize the collimation. However, the LED lighting system designed by this method has some defects, that is, the additional loss caused by the air gap between the lens and the LED. The following assumptions about the direct use of _ a collimating lens encapsulation of the chip, to prevent the occurrence of air gap. Because of the need for rotational symmetry, the encapsulation lens is designed as a cap type. At this point, the LED chip as a light source in the lighting system, it will be immersed in the lens, the light emitted by the LED through three different ways of collimation. In order to achieve a larger area of collimating light source, the lens must be designed to be scalable. Therefore, the upper surface of the lens can be designed into a regular hexagon, so that the LED light field after the package is all concentrated in the small emission angle, so as to realize the requirement of the collimating light source.

Interior lighting design

Since the indoor lighting source is easily seen by the human eye, its luminous surface should be as uniform and soft as possible. At the same time, indoor lighting must have a larger range, which requires the divergence angle should be at least greater than 120 degrees. In order to meet these requirements as much as possible and to ensure that the light source can be best utilized, it is necessary to make the light emitted by the LED illumination uniformly and diverge on the light emitting surface. Because the main light source in the room is usually located in the center of the room, so that the shape of the light field with rotational symmetry. Therefore, in the design process of a given distribution, not only to control the emission angle of light, but also to control the energy transmission of the light source. The design of the utility model can make the light outlet angle of the light source be controlled in the range of less than 60 degrees, and further realize the uniform distribution of the far field intensity, which is consistent with the requirements of the indoor illumination to the light source.

The three-dimensional light distribution design

We mainly study in interior lighting is designed for light distribution in two dimensions, and in order to achieve some complex and practical light distribution, we must understand the 3D design method. In the light of the three-dimensional design, in accordance with the specific requirements to determine the design ideas, usually can be taken to design 3D free surface separation of variables, it can easily obtain rectangular illuminance distribution, the design ideas in the design of LED street lamp on a more broad application prospects.