FEATURE OPTICAL DESIGN
“Software will always need to evolve to accurately model any new technologies in the industry, including light sources and materials”
g
LED sources. ‘Any optical design program aimed at the lighting market,’ he said, ‘should be able to handle these types of systems, as well as have the flexibility to work with any new design forms that may come along. As new designs and tighter requirements come into play more often, the ability to automatically optimise a design to a user defined goal, such as flux level, illumination pattern and uniformity, is also a key factor. This allows the user to test multiple designs in a short period of time, without user involvement.’
Design freedom For Jongewaard, the most design freedom – in terms of optical component-types, materials and lamp types – stems from the software providing a flexible interface on top of an extensible raytracing foundation. He said: ‘Providing optical design features directly in the CAD software allows designers to create any type of geometry they prefer, as well as leverage design tools we provide. Their CAD models can even include all mechanical features that interact with the light and affect performance. The simulations must start with accurate input to obtain meaningful results. Because of this, we have invested heavily in specialised measurement equipment to characterise both light sources and material scattering properties. As new technologies and application types come into the industry, having extensible raytracing and output features allows us to support the new technologies more quickly.’ The use of freeform surfaces to tailor output distribution is something that allows designers to match the source distribution characteristics to the desired lighting output
The spot produced by the collimator style lens while using all smoothly polished optical surfaces
distribution, David noted. ‘The LightTools advanced design module includes a set of specialised tools to enable fast, robust modelling of reflective and refractive freeform optics in both single-surface and segmented configurations. The LucidShape software for automotive lighting design includes capabilities that automatically calculate and construct optical geometries based on user-defined illuminance and intensity patterns,’ David said. ‘This is a functional approach that enables designers to focus on overall design objectives, rather than the implementation details of complex optical components.’ With the evolution of lighting
technologies and applications, the software also had to evolve, and Jacobsen believes this will continue, at least in the short term. ‘The software will evolve to include more and more properties as they become available, such as new light sources and new diffusers,’ he said. ‘Increased ease-of- use will allow software to be used by a wide base of users, either with or without optical design experience. The ease of file sharing and/or integration with CAD software – such as SolidWorks, PTC Creo, Inventor, Catia – is also very desirable and important, as it allows most of the design work to be done in the CAD environment; then the optimisation and analysis to be done in the optical design software.’
A collimator style lens designed in Photopia around a checkerboard array of warm and cool white Cree XD16 LEDs
18 Electro Optics October 2019
Ever evolving LTI Optics’ Jongewaard agrees that software will evolve as lighting becomes ever more innovative and is used in new ways. ‘Software will always need to evolve to accurately model any new technologies in the industry, including light sources and materials,’ he said. ‘In the coming years this could mean the adoption of OLED or laser diode-based lighting, and the expansion of micro-structured or holographic optical
The spot with nearly the same beam size, but with much better colour mixing, achieved using a combination of faceting and etching on specific lens surfaces
systems. Furthermore, design tools will continue to expand in scope to cover a broader range optic styles, performance criteria and constraints, while also working to provide the most tolerant designs to aid manufacturing. ‘Optical design software will also
continue to leverage all computational hardware available via multi-core CPUs, GPUs and cloud computing, to make simulations as fast as possible. This provides designers with more refined optimisations and more realistic product visualisations.’ Tom Davies, chief photonics engineer
at Photon Engineering, believes that simulation tools will play an ever-increasing role in the development of illumination systems, providing predictive analyses during product design and diagnostic forensics during the manufacture and test process. ‘Correspondingly,’ he said, ‘it becomes increasingly important that the software used should provide the highest fidelity results possible, in the shortest amount of time possible. That’s why we recently invested a lot of time creating a new core architecture for our FRED software to utilise the massively parallel computing capabilities of GPUs.’ For David, advances will be made by combining simulation tools. ‘Illumination design software will increasingly combine macro- and nano-optics simulation, previously considered different modelling disciplines. Synopsys is already making progress in this area with an optical design workflow for nano-textured diffractive optical elements that enable smaller, lightweight AR/VR devices with improved displays and immersive experiences,’ said David. ‘This combination of simulation approaches will help foster smaller overall device packages and the ability to simulate more diverse operating environments.’ EO
@electrooptics |
www.electrooptics.com
LTI Optics
LTI Optics
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