Optical Design: Software Interoperability Between CODE V & LightTools

Patrick Le Houillier

Jun 29, 2022 / 3 min read

The latest trend for many applications in optics is to bring multiple facets of optical design together to complete all the steps necessary to bring concepts to reality–from the proverbial clean sheet to the point when you bring the product to market. While some bridges exist between photonics and optics designs and between optics with multi-physics matters, perhaps the most compelling requirement is for a bridge between imaging and illumination design, where designs often require a level of iterative design that goes back and forth in the quest for perfection. Add to this the advancements in optimization and tolerancing, stray light elimination, and the importance of accuracy (especially for augmented and virtual reality systems leveraging sensors and optics, where user immersion is of paramount importance), and it is clear that interoperability between imaging and illumination models is a hot topic.

New Developments in Interoperability: the OSF File Format

For a few years now, LightTools has been able to leverage an interface with RSoft Photonic Device Tools in order to use patterns from LED extraction features to trace rays into the far field, and CODE V has been able to design projection lenses for use in LucidShape for advanced pixel lighting solutions for automotive headlight systems. To build on this momentum, the next step was clear: enable CODE V and LightTools to communicate as seamlessly as possible. The first step toward this goal has been accomplished, as CODE V 2022.03 and LightTools 2022.03 include features that enable these two software solutions to start speaking the same language. New grouping commands from CODE V, new lens design structures and surface modeling in LightTools, as well the new optical system file (.osf) format now enable a seamless transition for a CODE V model be opened in LightTools. On top of this, the new architecture allows you to bring in parametric updates when CODE V model improvements are needed.

cell phone camera lens in CODE V 2022.03

Fig 1. A cell phone camera lens in CODE V 2022.03

On the CODE V side, you start by opening a sequence file with the model of interest, like this cell phone camera, for example. After the initial model is made, CODE V 2022.03 can generate the .osf file for LightTools 2022.03 to read. Rays generated in CODE V for design and visualization purposes are also included in the .osf file.

On the LightTools side, you can start by loading a model that features the cell phone housing, which you can generate in LightTools or using SOLIDWORKS and the LightTools SOLIDWORKS Link Module. Then you can import the .osf file and mate it with the mounting geometry, with baffles and aperture stops being combined through Boolean operations. In the resulting model, you can either start the stray light analysis process or investigate mismatches or other potential issues.

.osf model of the same cell phone camera lens

Fig 2. The .osf model of the same cell phone camera lens, opened in LightTools 2022.03

If it is necessary to make changes to the optics in CODE V for performance reasons, you can import them via another .osf file, and LightTools preserves all of the changes internal to it such as optical property changes and Boolean operations. You are then free to work with the model as needed.

The same system, updated after an optimization in CODE V 2022.03, ready for stray light analysis

Fig 3. The same system, updated after an optimization in CODE V 2022.03, ready for stray light analysis

For models that contain more complex geometry and design surfaces made to represent prisms or a combination of optical elements of different shapes, it is necessary to indicate the design intent so that the order in which rays have to interact with surfaces in CODE V is properly indicated in LightTools 2022.03, which now supports surface-based ray tracing.

The design intent of the surface group determined in CODE V dictates how LightTools perceives prism lines and builds the geometry.

Fig 3a. and 3b. The design intent of the surface group determined in CODE V dictates how LightTools perceives prism lines and builds the geometry.

The Path to Interoperability

Being able to take work from CODE V to LightTools is the first step toward full interoperability. LightTools 2022.03 is where multiple disciplines meet, with imaging joining illumination, then enhanced by mechanical CAD. The new and improved interoperability features between CODE V and LightTools enable you to easily simulate optical systems that contain imaging and non-imaging components, thereby streamlining product development time. You can leverage the industry-leading design, optimization, and tolerancing capabilities of CODE V and LightTools to develop a broad range of optical systems, from augmented reality headsets and head-up displays to smartphone optics and electro-optical imaging systems.

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