geometry Tag

Application Example: Color Mixing Lightpipe

LEDs, have surpassed incandescent light sources in recent years for most applications. Benefits of the LED include compact size, high power efficiency, and a long lifespan. LEDs also have undesirable qualities that optical engineers must address, such as the need for color mixing and collimation....

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Application Example: Mobile Displays

Mobile devices such as smartphones, e-readers, and watches are becoming ubiquitous in today’s world. Precise optical engineering is required to optimize the performance of mobile features such as the camera system, sensors, and the display. A key design objective for a mobile display is uniform...

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Afocal Optimization

The attached FRED example demonstrates how to optimize the inter-lens spacing of a Galilean beam reducer using geometric ray collimation as the optimization metric. Open the model and expand out the Geometry folder and the Collimator subassembly node.  Observe that there are three geometry elements...

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Importing Doublets

This article outlines the general process for importing a Cemented Doublet from an optical model, using an Edmund Optics 45089 Achromat as an example (Zemax file used).  When FRED imports a doublet, two individual singlet elements are created and the user has two options: Use...

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Compute Distance Between Objects

The attached FRED file contains an embedded script which shows how you can calculate the distance between two objects using the scripting language. The script works by using the TransformPosition command, which takes a starting coordinate system, a new coordinate system and a position vector...

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CAD Surface Position and Orientation

When FRED imports a CAD model, all of its surfaces are defined by NURBs, or trimmed versions of those NURBs called Trimmed Parametrics. These parametric surfaces are always defined in the global coordinate system. One of the major difficulties with this definition is that the...

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Axicon Lens Example

This is a model of a Thorlabs Axicon Lens AX2520-UV which is used in this model to convert a plane wave input beam into a ring profile. The raytrace is performed coherently using FRED’s Gaussian Beam Decomposition technique. To minimize ray errors at the center...

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Cassegrain Telescope Builder

A while ago, I was reading through Joe Geary’s excellent book, “Introduction to Lens Design” 1, and it occurred to me that his first order construction of a Cassegrain telescope could be very easily written up as a BASIC script in FRED. The example file that...

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Optimizing Lens Modules

The Lens Module family of surfaces (Infinite conjugate, finite conjugate, afocal and spherical) provide a convenient mechanism for quickly defining an ideal lens element.  If the circumstance arises where a lens module surface is desired to be included in an optimization, the user will find...

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Telescope Model Using OAP’s

This knowledge base article demonstrates modeling of a three mirror 5x afocal telescope system as prescribed in “Modern Lens Design: A Resource Manual” by Warren Smith (McGraw Hill).  This article discusses how to construct the off-axis parabolas (OAPs) in FRED using the surface apertures to...

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