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Application of non imaging optics in LED lighting

At present, under the situation of global energy shortage, energy saving has become a serious problem we have to face. Lighting system in the light of the people at the same time, also all the time consumption of electricity, in order to minimize the consumption of electricity, energy-saving lighting system has been more and more attention. LED has been widely used in many fields because of its low energy consumption, long service life and high economy. Design of LED lighting system in the past is in the experiment using the model to complete, after the completion of the design once found its optical properties do not meet the requirements, we must re design, thus wasting a lot of manpower and financial resources. With the development and progress of Applied Optics, the theory and method of non imaging optics are also improved. Based on this point, this paper discusses the application of non imaging optics in LED lighting.

Non imaging optics and related concepts

Non imaging optics

Different from the traditional optical imaging and non imaging optics is not able to focus on light quality imaging and imaging in the target plane, the main concern is the utilization of energy source and the energy in the azimuth angle and the space of the specific distribution. As shown in Figure 1, in the imaging optical system, the main point is the light intensity and position information, and in the non imaging optical system, the main point is the energy transfer and re combination and distribution.

Figure 1 Schematic diagram of imaging and non imaging optics

Energy collection rate

Non imaging optics mainly focus on the distribution of energy, if the establishment of a as shown in Figure 2 of the non imaging optics model, from which they can see clearly that the plane A is represented by the entrance aperture area, and the plane A where is the exit aperture area. In the following example, we assume that the aperture area A of the device can make all the light pass through the area, and the ratio between the incident beam area and the beam area is C. Under normal circumstances, the maximum energy collection rate of 2D system is C2D=l/sin, while in the rotationally symmetric 3D system, the maximum collection rate is C3D=1/sin2. The concept of energy harvesting rate is mainly used in the evaluation of non imaging optical systems.

Figure 2 the concept of energy harvesting rate

geometrical optics

At present, geometrical optics has been widely used in the design of optical systems. The imaging optics and non imaging optical systems must be based on the theory of geometrical optics. There are four basic laws of geometrical optics, namely the law of rectilinear propagation of light, the law of independent propagation, the law of refraction and the law of reflection.

(1) the law of rectilinear propagation of light. The law states that the problem is that light travels in straight lines in a homogeneous and isotropic medium.

(2) the law of independent propagation of light. The light beams emitted by different light sources are independent of each other in a different direction, and do not affect each other.

(3) the law of reflection of light. When the three kinds of light of incident, reflection and projection are in the same plane, the reflection angle is equal to the absolute value of the angle of incidence and the sign is opposite.

(4) the law of refraction of light. Compared with the law of reflection, it is also that when three kinds of light are in the same plane, the angle of incidence and the angle of refraction are not related to the size of the angle.

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