From flash lenses in mobile phones to LED lighting solutions in automotives, LED lenses are fully designed in-house in Shapeoptics. This article will share how to design and create an LED Lens using an optical illumination design software.
The following LED Lens is meant to house 7 LED light sources and acts to generate an intense beam of light for illuminating small objects. The 7 cell cluster LED Lens is molded from polycarbonate and sits atop a 7 cell LED lenses array. The LED Lenses may look like a fairly complex part. Upon closer inspection, the part may be broken down into 3 segments. The profile of the part suggests that it is cut from a single lens part. The large hole in the center of the part is also cut from a lens shape. The radial “flower” shape of the part consists of 6 hexagons, intersected with 6 compound parabolic concentrators (CPC) with lens shaped holes cut at the base of each CPC.
This article will break down the 7-Cell LED Lens into several simple pieces to create a fully parametric part. Before starting a part, it is important to know which features of a part need to be parameterized in the LED lenses. The overall thickness and diameter of the part will be parameterized. Other measurements representing the diameter of certain gaps and cuts will be represented by the constant, diamRatio. This ratio is attained from the initial specifications of the part. Each of these values is defined below:
Step 1 Design the main Lens
The main body of the LED Lens is created with the following commands:
After creating the initial lens, another smaller lens is created to act as the area subtracted from the main lens. The RAY command becomes very effective in positioning parts with respect to other parts. The RAY command will grant the user access to the location of a ray intersection specified in the RAY command. The resulting values act similarly to variables created by the CONSTANT command, and can undergo mathematical operations. In this example, the smaller lens needs to be placed close to the front surface (along the +z-axis) of the larger lens. Due to the curvature of the lens in the LED lenses, the placement of the smaller lens is not apparent without some calculations.
Step 2 Design the polygon shape
The polygon shape of the LED Lens is created with the following commands. This shape is made up of 6 hexagonal polygons arranged like a honey comb:
The parameters defining the base polygon utilize the user defined parameters. This ensures that the entire part may be fully parametric in the LED lenses. The “honey comb” pattern of the polygons is created through a ring array of the initial base polygon about the z-axis. It is important to note that the base shape used in a RING command must first be offset from the specified axis of rotation. Because the geometries are rotated about the origin (axis of rotation will be the z-axis), a copy of the initial polygon must be created and placed on top of the base shape. Once again, the top of the polygon is not clear without some tedious math, and a RAY command is used to find the offset distance of the copied polygon. And finally, the initial base polygon and the ring copies are then joined via the UNION command
Step 3: Design the CPC Array in the LED lens array
The next step requires operations utilized within all prior sections. The following commands detail an array of CPC objects that will be placed behind the newly created polygons for the LED lens array.
A ring array of 7 compound parabolic concentrators has small air LED lenses drilled at the rear apertures. Once again, the CPC geometries must be defined by the parameters declared at the beginning of the script. An individual CPC object with a hole is copied and offset along the y-axis using the same values attained by the previous RAY operation. The copied CPC is then rotated using the RING command and combined with the original CPC located at the origin.
Step 4: Finalize the Led lenses Array
The commands and images below show the objects that will be overlapped (polys and cpcLobes) as well as the overlapped parts and the resultant object named finalLED .
The object final LED lens is now ready to be exported as a CAD file (.IGS, .STEP,.STL, .SAT) or saved as a .ZSO or .ZPO file, to further ray tracing optimization and design in the LED illumination application.
The design file used in this particle is attached, please download it here.Design LED Lens array
Reference Source:
- https://www.zemax.com/
- Zemax Optical Design Program User’s Guide, Zemax Development Corporation
- https://en.wikipedia.org/wiki/Main_Page
