Modeling Light Shaping Diffusers® in Zemax OpticStudio

Submitted on Thu, 11/10/2016 - 18:09

A unique platform developed by Luminit allows engineers and designers to accurately emulate the performance of Light Shaping Diffusers.

by Luminit Staff

If you subscribe to the belief that time is our most precious resource, then you may want to explore Luminit’s new LSD scatter model for Zemax OpticStudio. We designed this proprietary optical model so customers can visualize the output distribution of a Light Shaping Diffuser (LSD) and choose the right angle for their optical system, eliminating guesswork and saving hours of valuable time. The program is different from conventional optical design programs because Luminit diffusers are different from conventional diffusers.

How Luminit Light Shaping Diffusers Work

Unlike other light diffusers, Luminit LSDs use holographic diffuser technology to create pseudo-random micro-lens structures. Holographic patterns are imbedded on polycarbonate or polyester sheets, and these patterns can manipulate light by changing the direction of its energy. Because it works on the principle of surface scatter instead of volume (bulk) scatter, Luminit LSDs tend to have a much higher transmission efficiency and are designed to reduce the effects of diffraction, which eliminates zero order and chromatic variation (rainbow appearance).

scanning electron microscope view of light shaping diffuser

A scanning electron microscope (SEM) view of an LSD surface microstructure.

LSD Scatter Model: Calculating the Result

Last year, Luminit engineers developed a proprietary optical model that accurately calculates transmission characteristics or Bidirectional Transmission Distribution Function (BTDF) of our Light Shaping Diffusers. We took this one step further and created a model that allows users to emulate the transmission distribution of Light Shaping Diffusers within the Zemax OpticStudio platform (Professional and Premium versions only). While conventional optical design programs provide bulk scatter and surface scatter models based on mathematical probabilities or algorithms that predict output distribution,  Luminit’s optical model closely emulates our characteristic LSD profiles of transmission with a large range of incident angles and wavelengths. Utilizing the Zemax  “User Defined” type of scatter model, a Luminit proprietary function defines the statistical direction of the rays which allows the shape of the diffusion to follow the Luminit LSD product.  The model is designed to scatter the light at the surface of a volume object and allows you to select the catalog angle you desire. The files take the form of a DLL (Dynamic Link Library), which is native to OpticStudio and maximizes the processing speed of the ray trace.

Examples of Measured Profiles (Left) Compared to Modeled Profiles (Right)

1 degree lsd

30 degree

 

60 degree

Goniometer Readings: From 1 - 30 degree LSDs, the shape of the profile is fairly Gaussian. LSDs past 30 degrees the shape transitions into Trapezoidal then M shaped.

 

tilted measures

 

tilted measures

Measures Off-Axis: Luminit’s LSD scatter model can simulate tilted or off-axis light sources with excellent accuracy, which is particularly useful for elliptical angles. The first example is tilting a 60 degree LSD 60 degrees. The second example is tilting a 60x1 LSD 60 degrees.

Enhancing the Design Process

Luminit’s LSD scatter model for Zemax OpticStudio allows engineers to make an educated choice during the design process and is just another example of how Luminit stays on the forefront of science and technology to our customers’ efforts during the design cycle. The files are available for free and can be downloaded directly from the downloads tab on this website.