FEATURE OPTICAL DESIGN
Model behaviour
Keely Portway looks at how optical software is being used to design light sources
T
he use of optical modelling in the design of lighting systems has increased in recent years, largely due to the transition to energy-
efficient LEDs. And, with the emergence of other lighting technologies, such as solid- state lighting and OLEDs, optical design software is a key tool for non-experts to create a range of innovative lighting products that are used in increasingly imaginative ways. One of the latest trends in the lighting
market, according to Dave Jacobsen, senior application engineer at Lambda Research Corporation, is the move to more compact and higher performing luminaires. ‘Many of the new, smaller designs are taking advantage of the benefits LEDs bring to the table,’ he said, ‘and OLEDs are showing up in display applications, adding a new option for these types of applications.’ This need for smaller and more efficient light sources is important for applications such as architectural lighting, said Stuart David, group director of applications engineering at Synopsys’ optical solutions group. ‘Freeform lenses and freeform reflectors can reduce the physical footprint of light sources in architectural lighting,’ he said, ‘while also making it possible to achieve new photometric qualities.’
Size matters Mark Jongewaard, president at LTI Optics, noted that many of the new trends in lighting systems are still driven by the prevalence of LEDs as the primary light source. He said: ‘The small size of LEDs compared to other sources like fluorescent or HID (high intensity discharge) has allowed for the design of smaller and more precise optical systems, as well as more flexible form factors for large, luminous
16 Electro Optics October 2019
surfaces. The range of spectrums available from LEDs has also led to the increased use of colour mixing in general lighting, whether for RGB mixing, variable white tuning, or tuning for specific reasons like circadian lighting for human health or plant growth cycles in horticultural lighting.’ As more off-the-shelf optical components become available for LEDs, Jongewaard continued, it is important to design custom optical systems that better meet the needs of a specific market to maintain product differentiation. When it comes to lighting design, one notable trend, according to Jacobsen, is the assignment of design tasks to engineers that do not necessarily have an optical design background. This could prove challenging, as there
are a number of key considerations when designing a light source. David said: ‘If you are designing an LED source, you need to consider maximising the photon extraction from an LED die to improve luminance. Maximising output power or minimising the electrical energy is also important, as is optimising package size for a particular application and managing the output spectrum to improve colour rendering. Optical design software for lighting applications can help designers address all of these design considerations.’
Synopsis’ LightTools software, for
example, has a set of capabilities for simulating colour rendering, or chromatic effects in an illumination system. Software such as this can be used to automatically optimise a design to achieve the best chromatic performance, based on the application’s particular requirements.
Design for life
When designing a new light source, the first step usually starts with a specification or a market need, according to Lambda’s Jacobsen. ‘This could be a certain illumination level, a lighting pattern, or a certain architectural look to the luminaire,’ he said. The next step is to select an appropriate source for the luminaire, which has the necessary light output and spectrum for the application. ‘Factors such as source life and serviceability may also need to be considered,’ added Jacobsen. ‘Then start the design process, which can be done using optical design and analysis software, or manually by hand. In either case, being able to draw on training or past experience gives the designer a leg up in getting started. After the design process has been completed it is time to build a prototype and test it to see if the finished product meets the initial requirements.’
Design of diffractive optical elements for augmented
and virtual reality applications in
Synopsys’ RSoft and LightTools products
@electrooptics |
www.electrooptics.com
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40
