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EspañolWhen designing the LED lighting system, first determine the design requirements and conditions, such as materials, lighting system structure, light source distribution, etc. According to these relevant requirements, determine what kind of optical design it belongs to, that is, 2D system, rotationally symmetric system or 3D system, and then select different design methods according to the specific optical design. The size of LED chips is generally negligible, and to further simplify the design process, a point light source scheme can be used for design.
3.1 Design of optical coupling system
Usually, in practical applications such as projection lights, projector light sources, and night lighting systems, a collimated projection surface light source is often required. Specifically, it is necessary to obtain a surface light source with a relatively small projection angle. When the light is projected onto the subject, it will be captured by the human eye through diffuse reflection. We can consider LED chips as an approximate Lambert light source, with a relatively large divergence angle and a far field distribution that cannot meet the requirements. At the same time, the light energy output by a single power type LED chip cannot meet the actual required brightness. Therefore, the collimating LED optical system not only needs to achieve the collimation output of the light emitted by the LED chip on a large area, but also needs to be easy to expand. Some designs usually use secondary optical elements to achieve collimation of light sources. The so-called secondary optical elements specifically refer to the use of collimating lenses in conjunction with packaged LEDs to achieve collimation. However, the LED lighting system designed using this method will have certain drawbacks, namely the additional loss caused by the air gap between the lens and the LED. Let's assume that we can directly use_ A collimating lens encapsulates the chip to prevent the generation of air gaps. Due to the need for rotational symmetry, the encapsulated lens is designed as a cap type. At this point, the LED chip serves as the light source in the lighting system, which is immersed in the lens. The light source emitted by the LED is collimated in three different ways. In order to further achieve a larger area of collimated light source, the lens must have a certain degree of scalability during design. Therefore, the upper surface of the lens can be designed as a regular hexagonal shape, so that the packaged LED light field can be concentrated in a smaller emission angle, thereby achieving the requirement of collimating the light source.
3.2 Indoor Lighting Source Design
Due to the fact that indoor lighting sources are easily visible to the human eye, their luminous surface should be as uniform and gentle as possible. At the same time, as indoor lighting must have a large range, it is required that the divergence angle should be at least greater than 120 °. To meet these requirements as much as possible and ensure the best utilization of light sources, it is necessary to ensure that the light emitted by LED lighting can be evenly and diffusely illuminated onto the emitting surface. Because the main light source indoors is usually set at the center of the room, resulting in a rotational symmetry of its light field shape. Therefore, in the design process of a given distribution, it is not only necessary to control the exit angle of the light, but also to control the energy transmission of the light source. This design can control the output angle of the light source within ± 60 °, and further achieve uniform distribution of far-field light intensity, which is fully consistent with the requirements of indoor lighting for the light source.
3.3 Design of three-dimensional given light distribution
In indoor lighting, our main focus is on the design of two-dimensional given light distribution, and in order to achieve some more complex and practical given light distribution, it is necessary to understand its design methods in three-dimensional. When designing three-dimensional given light, the design idea can be determined according to specific requirements. Usually, the three-dimensional Free surface with separated variables can be used for design, so that it is easy to obtain rectangular illuminance distribution. This design idea has a broad application prospect in the design of LED street lights.
