Fresnel lens, threaded lens: Parametric generation

A Parametric Fresnel Lens Generator

A parametric Fresnel lens generator based on OpenSCAD, allowing you to get the Fresnel lens you want without needing to learn optical principles. Through a simple UI, you can generate Fresnel lens models of various focal lengths and diameters, with adjustable parameters and being fully open-source. It is very suitable for educational demonstrations or as a geek toy, and can also be used as a component in your projects. However, please note that due to the limitations of FDM printing resolution and material refractive index, the printed lenses will have significant errors. They are only suitable for decoration, educational demonstrations, or as geek toys, and are not suitable for optical applications.

I tried to print some scaled-down studio light models, but couldn't find suitable Fresnel lenses, so I wrote this small tool to generate Fresnel lenses. You can use it to generate Fresnel lenses of any focal length and diameter, for the front of flashlights, spotlights, or anywhere you want to focus light. I recommend using a smooth build plate and applying a UV coating after printing for better results.

A Fresnel lens, also known as a threaded lens, was invented by the French physicist Augustin Fresnel. One side of the lens surface is smooth, while the other side is etched with concentric circles of increasing size. Its texture is designed based on light interference and diffraction, as well as requirements for relative sensitivity and reception angle.

Parameters:

• Focal Length: Determines the focusing distance of the lens;
• Diameter: Controls the opening size of the lens;
• Number of Rings: The number of Fresnel steps; a higher value results in a smoother approximation;
• Base Thickness: The thickness of the flat base of the lens, ensuring structural strength;
• Material Refractive Index: The refractive index of different plastics or resins can affect curvature calculations;
• Model Quality: Sets the number of geometric subdivisions, affecting detail and rendering speed.