Lighting-based LED array research and simulation
Huo Yanming Wu Shumei (School of Electrical and Information Engineering, Hebei University of Science and Technology, Shijiazhuang 050018, China)
Abstract: LED is a green light source in the 21st century with broad lighting prospects. This paper first calculates the illuminance superposition of the LED array, and then simulates the array according to the superposition formula, analyzes the simulation results of the two LED array distributions, obtains the distribution characteristics of different arrays, compares the characteristics of the two arrays, and finally analyzes the different array distribution. Applicable luminaires provide a reliable basis for LED luminaire design .
Keywords: LED, array, simulation
LED is a kind of energy-saving and environment-friendly light source with long life, low power consumption and no radiation. Most experts predict that the 21st century will be based on solid luminescent materials, that is, the new light source represented by LED and the century of green lighting. LED light sources have a bright future. In recent years, there have been more and more types of LED lighting products, and it is particularly important to design suitable LED lamps. Since the power of a single LED is small, as a lighting, it is required to have a certain uniform luminous flux and illuminance in the illumination area. Therefore, it is necessary to adopt an array form of LEDs, increase the luminance and the light-emitting area of ​​the LED, and improve the uniformity of illumination. In this paper, the LED array is simulated and analyzed according to the simulation results. The characteristics of various arrays are obtained, and the lamps suitable for this array are analyzed to provide accurate reference basis for LED lamp design.
1. LED and its lighting applications
LED (Lighting Emitting Diode) is a light-emitting diode that uses a solid semiconductor chip as a light-emitting material. In the semiconductor, the carrier emits excess energy to cause photon emission, and directly emits red, yellow, blue, green, and blue. Orange, purple, white light. Because it is an energy-saving and environment-friendly light source with long life, low power consumption and no radiation, in recent years, LED light sources, especially white LEDs, have attracted great attention.
LED applications in the field of lighting mainly include night lighting, automotive lighting, traffic lights, special general lighting, special lighting and security lighting. With the continuous improvement of LED luminous efficiency, LED lighting will slowly replace incandescent lighting and enter thousands of households.
2. LED array illumination calculation and its distribution research
2.1 Calculation of LED array illumination
Luminosity refers to the degree to which an object is illuminated, expressed in terms of the luminous flux per unit area, expressed in units of Le [x] (Lux), or lm/m2. 1 勒 [克斯] is equal to 1 lumen [明] (lm) luminous flux is evenly distributed over 1 m2 of illuminance. The illuminance of an LED array is a linear superposition of multiple individual LED illuminances. Therefore only a single LED illumination is analyzed.
Usually the target distance illuminated by the LED is much larger than the LED itself, in which case the LED tube is reduced to a point source with a spatial intensity distribution. The point source is characterized by the ability to emit light of the same luminous intensity to the surrounding space at a 4 solid angle. Assuming that the bin dS receives the illumination of the LED point source S, the distance from the point source S to the bin dS is r, and the angle between the optical axis of the meta-beam emitted by the point source and the normal N of the bin is The illuminance on the panel is:
The light intensity distribution of the LED is not an ideal cosine distribution, which can be expressed as:
When the LED illuminates a plane perpendicular to its optical axis direction, the illuminance distribution on that plane is:
The above formula is the basis of the following LED array illumination simulation.
2.2 LED array research
2.2.1 Analysis of LED spacing in LED arrays
Since the LED is an incoherent light source, the illuminance of one LED to a certain area on the plane is a single superposition (multiple LEDs superimposed in the same way), then (where d is the distance between the two LEDs)
When d is increased to 0.0218, the illuminance of the area near the origin does not decrease much, and the distance is appropriate. The calculation results can be verified by simulation. As shown in Fig. 1, when d=0.0218m, the illumination near the origin is relatively uniform.
2.2.2 LED array distribution research
LED array distribution mainly studies the distribution pattern of LED arrays. According to the different distribution patterns of arrays, it can be divided into surface arrangement and stereo arrangement.
The surface arrangement is further divided into a plane arrangement and a surface arrangement. The planar arrangement of light distribution means that a plurality of LEDs are evenly arranged, and the angle between the axial directions is zero, and is mounted on a planar substrate to form a surface-emitting light source having a certain area. Its characteristics are: small illumination area, concentrated light output, uniform illumination, and high illumination. According to the functional requirements used, the specific shape of the light-emitting surface includes a rectangle, a circle, an ellipse, etc.; the surface arrangement mainly includes a cylindrical arrangement, a spherical arrangement, an irregular arrangement, and the like.
The stereo arrangement mainly includes a sphere and a cylinder.
In view of the space, this paper only analyzes the arrangement of the rectangles in the plane arrangement and the arrangement of the inner semi-cylindrical surfaces in the arrangement of the surfaces. The stereo arrangement is actually a special case of the arrangement of the surfaces (not only the illumination of the bottom surface but the illumination of each surface), and no specific analysis is performed.
3. LED array simulation and comparative analysis
The LED array was simulated with Matlab software.
3.1 Simulation results and analysis of rectangular plane
Figure 2 shows the simulation results of a 7 × 17 rectangular array. In this simulation, the array is 6 meters away from the illumination surface (the simulation distance should be changed according to the specific luminaire).
From the simulation results of Fig. 2, we can see that the center maximum illuminance of the 7×17 rectangular array is about 40 Lux, and the area of ​​the over-maximum illuminance, that is, 20 Lux, is about 0.75 m from the center. It can be seen from the above data that the illumination range of the rectangular array is relatively concentrated, and the lamps distributed by such arrays are suitable for the illumination field where the illumination surface is small and concentrated.
3.2 Simulation results and analysis of the inner semi-cylindrical surface
Figure 3 shows the simulation results of a 7×17 inner semi-cylindrical array. Ibid., the simulation takes the array from the illuminated surface to 6 meters.
From the simulation results in Fig. 3, we can see that the central maximum illuminance of the 7×17 inner semi-cylindrical array is about 3.3 Lux, and the area of ​​the maximum illuminance is half of the 1.65 Lux area, and the x-axis is about 7 m from the center. The y-axis is in the range of 0.8 m from the center. According to the above data, the illumination range of the inner semi-cylindrical array is distributed in a strip shape, and the array-distributed lamps are suitable for an illumination field in which one of the upward illumination areas is large and the illumination area is smaller in the vertical direction.
3.3 Array distribution on plane and surface comparison
For the two arrays analyzed above, the LEDs and the number used are the same, but according to the simulation results, we can see that there are great differences in illumination size and illumination area. The center of the array representing the rectangular distribution of the plane is relatively large, reaching 40 Lux, but the illumination area is relatively small, only about 0.75 m in the 20 Lux, and the center illumination of the array representing the inner semi-cylindrical surface of the curved surface is relatively small. It is only 3.3Lux, but the irradiation area is relatively large, and the area with half of the maximum illuminance value reaches 7m in one direction.
Comparing the simulation results, it can be concluded that the planar distribution array has small illumination area, concentrated light output, uniform illumination, and high illumination. It can be applied to module illumination, photoengraving, vanity mirror, concentrating (projection) lamps, etc.; The irradiation area is large, with divergent lighting effect, and special decorative lighting effects can be obtained, which are suitable for square lamps, street lamps, and the like.
4. Conclusion
In short, for the illumination calculation and distribution of LED arrays in LED lighting fixtures, the article focuses on the simulation and detailed analysis of LED arrays in specific designs and distributions, which has certain reference value for designing more perfect LED lamps. It is believed that with the continuous development of LED technology and the continuous improvement of the design and manufacture of LED lighting, new and better technical solutions and products will emerge in an endless stream.
references:
[1] Zhang Wei, Liu Tiegen, Zhang Xuemin et al. Simulation and distribution of LED road lights and experimental verification. Optical instruments, 2008.2
[2] Hu Hailei. Design of LED illumination optical system and its array illumination distribution research. Master thesis, 2005.4
[3] Wang Le. LED application and simulation of lighting. Journal of Lighting Engineering, 2007.3
[4] China Green Lighting Project Promotion Project Office, Department of Light Source and Lighting Engineering, Fudan University. Lighting Design Part of China Green Lighting Engineering Training Materials.
[5] Zhang Ping. A brief tutorial on the basics and applications of MATLAB. Beijing Aerospace University Press, 2002.3
[6] Yang Guang. Arrangement and Light Distribution of White LED Arrays in Lighting Fixtures. Lamps and Lighting, 2008.3
About the author: Wu Shumei, born in February 1980, female, graduate student of Hebei University of Science and Technology, research direction detection technology and automation equipment.
Huo Yanming, male, professor, professor of Hebei University of Science and Technology, Ph.D.
(This article is from the 2008 China Optoelectronic Industry High-level Forum Proceedings)
Wall brackets of cable tray are essential components in cable management systems. They are used to support cable trays on walls, ensuring that cables are organized and protected from damage. In this article, we will discuss the different types of wall brackets available in the market, their features, and how they are used.
Types of Wall Brackets
There are several types of wall brackets available for cable trays, including:
1. Standard Wall Brackets: These brackets are the most commonly used and are designed to support cable trays at a fixed distance from the wall. They are available in different sizes and materials, including galvanized steel, stainless steel, and aluminum.
2. Adjustable Wall Brackets: These brackets are designed to provide flexibility in the installation of cable trays. They can be adjusted to different angles, allowing for the installation of cable trays on uneven surfaces.
3. Ladder Rack Wall Brackets: These brackets are designed for use with ladder-style cable trays. They are available in different sizes and can be used to support cable trays at different heights.
Features of Wall Brackets
Wall brackets of cable tray come with several features that make them suitable for different applications. Some of the features to consider when choosing wall brackets include:
1. Material: Wall brackets are available in different materials, including galvanized steel, stainless steel, and aluminum. The choice of material will depend on the application and the environment in which the cable tray will be installed.
2. Load Capacity: Wall brackets come with different load capacities. It is important to choose a bracket with a load capacity that is suitable for the weight of the cable tray and the cables it will support.
3. Adjustability: Adjustable wall brackets provide flexibility in the installation of cable trays. They can be adjusted to different angles, allowing for the installation of cable trays on uneven surfaces.
4. Corrosion Resistance: Wall brackets made of galvanized steel or stainless steel are resistant to corrosion and are suitable for use in harsh environments.
Wall Brackets Of Cable Tray,Heavy-Duty Wall Brackets,Cantilever Wall Brackets,Tray-To-Tray Wall Brackets
Rayhot Technology Group Co.,Ltd , https://www.cnrayhot.com