It’s fair to say the LED lighting industry is now a mature and highly commoditised space. The supply chains for core LED lighting components – from the LEDs themselves to control electronics and secondary optics – are well-established. With so many vendors offering off-the-shelf solutions, it’s tempting to think that most LED products can be built from catalogue parts alone. And in many cases, that’s absolutely true. Here David Scott-Maxwell, Director at Forge Europa, shares key insights and considerations.
The Limits of Standard Secondary Optics
But what if you’re trying to do something different? Maybe you’re looking to add tangible value and stand out in a saturated market, or perhaps you’re developing a novel LED application in a specialist sector that doesn’t fit neatly into the “general lighting” box. In situations like these, customisation becomes essential – and some of the most powerful differentiation can be found in custom LED optics.
Why optics? Because standard secondary optics are, by necessity, designed to serve a broad range of use cases. That means compromises – on beam shape, efficiency, form factor, or integration. But here’s the good news: custom LED optic design is not only possible, it’s very often quicker, easier and more cost-effective than most expect. That said, one golden rule applies – never design optics in isolation.
To fully unlock the benefits of optical customisation, the optics must be treated as a fundamental part of the entire LED product design. Only by designing LED optics in tandem with the light source, thermal management, control gear, mechanics, and aesthetic considerations can you realise true optimisation.
Very few organisations have both the technical scope and the practical experience to do this well – Forge is proud to be one of them.
Let’s Define Our Terms: What is an LED?
But before we get into the “how,” let’s go back to basics: What exactly do we mean by LED optics? What role do they play in an LED system? And why are they so essential?
First, let’s define the term ‘LED’. We’re talking here about the bare electronic component – the Light Emitting Diode – which, when powered via control electronics, emits light. Commercially available since the 1960s, today’s LEDs come in a vast array of shapes, sizes, power levels, and colours.
But one key characteristic of LEDs has changed little since the 1960s – the light they produce is still of limited use on its own. Most LED light emission is unfocussed, which means it needs help to become usable in real-world applications. In technical terms, modern LEDs typically emit light from a flat surface, and their intensity varies according to the cosine of the viewing angle. This isn’t new – the cosine emission pattern, known as ‘Lambertian’, is named after Johann Lambert, who published a foundational book on light measurement – Photometria – way back in 1760.
Primary Optics vs Secondary Optics
While some LEDs incorporate built-in lenses – so-called ‘primary optics’ – these typically only focus the LED light emission modestly and don’t produce light that is particularly useful in real-world applications. To address this, it’s common to use separate optical systems positioned in front of the LED to collect, shape, and direct the light. These are known as ‘secondary optics’.
Such LED secondary optics can take many forms – lenses, reflectors, fibres, light guides, diffractors, prisms – and often combinations of these working together.
And while there are plenty of high-quality off-the-shelf LED secondary optics available, they all share the same limitation – they’re constrained in one way or another. That might be in terms of beam shaping, physical dimensions, optical efficiency, or even cost. Customisation, then, offers a clear path to overcoming these limitations and unlocking unique value in your LED-based product.
Cost Assumptions – And the Reality at Forge
But what about cost? There’s a common perception that custom optical components are prohibitively expensive – that the design time, tooling costs and minimum order quantities make them unviable unless you’re producing at huge scale.
While that may have been true in the past, it’s certainly not the case at Forge. With over 30 years of experience, advanced design tools, and flexible manufacturing, we can put some bold and very achievable numbers on the table.
Custom LED secondary optics are typically designed within a few weeks to a few months. The ODM design cost? Zero – we don’t charge for design (subject to the usual Ts & Cs, of course). Tooling costs are usually in the low thousands, and low-volume manufacturing runs – starting in the hundreds of units – are entirely possible.
The old saying goes “Good, Quick, Cheap – pick any two”. In most industries that holds true. But when it comes to custom LED optics, we’re confident we can challenge that rule.
How to Approach LED Optic Design
But how do you design LED secondary optics? Where do you start? Well, as mentioned above, the first and most important rule is this – don’t start with the optic. It’s essential to approach LED product design from a whole-product perspective. That’s because the various design decisions are all tightly interconnected – and often competing. For example:
What LED or LEDs should you use?
How do you meet efficiency targets?
What mechanical constraints need to be considered?
How will the control electronics be realised?
What are the aesthetic and optical requirements?
How do you meet the target product cost?
At Forge, we’ve learnt – sometimes the hard way – that by tackling these decisions together, and iteratively, we can optimise every element of a custom LED product and deliver exceptional performance and innovation.
So, what does this look like in practice for custom LED optic design? Typically, the first step is to decide which LED or LEDs to use. At Forge, we’ve built deep and long-standing relationships with all major LED manufacturers and have a solid understanding of the global LED landscape. This allows us to identify and evaluate multiple viable options – and we often do just that, iterating through different candidates as the design evolves.
Simulation, Prototyping and Real-World Testing
The design process itself combines simulation and hands-on experimentation, pulling in a range of disciplines – from optical physics and mechanical engineering to electronics and production design.
We begin with mathematical modelling, using software to trace the path of light rays from the LED through the optical system and on to the end user. This process – known as ray tracing – demands a strong grasp of optical physics, material behaviour, and manufacturing realities. Our team use convergence tools to refine designs, typically exploring multiple optic geometries during the day, then running overnight ray tracing simulations to home in on the optimal solution.
Why Prototyping Still Matters
While simulation takes care of much of the optic design process, we’ve found that in almost all cases, prototyping is still essential. That’s because real-world manufacturing processes – particularly plastic injection moulding – introduce uncertainties that simulation tools can’t always predict. Things like light beam patterning or unwanted colour separation often only become apparent during physical testing.
To address this, we’ve developed a rapid prototyping capability focused on the most common type of LED optic – injection moulded plastic lenses. We’re able to cut small, single-cavity tools that can produce tens or even hundreds of prototype parts in as little as a couple of weeks.
Material Choices for Optical Components
Lenses like these can be manufactured from a range of materials depending on the application, with the most common being optically clear polycarbonate (PC) and acrylic (PMMA). Glass and silicone can also be used where their specific mechanical or optical properties offer advantages. Reflectors, meanwhile, can be produced from metals such as aluminium or from plastics with sputtered reflective coatings that can be tuned for specific optical filtering effects.
Once prototype optics are ready, we can begin early-stage testing alongside the LED, control electronics, thermal management, enclosure, and other system elements. This enables rapid evaluation of the complete product, allowing performance to be measured and the design to progress confidently toward completion.
Production Tooling and Beyond
Once we’re satisfied with the prototype optics, we move on to manufacturing the production tooling. For plastic lenses, this typically involves creating multi-cavity moulds with the necessary features for part removal and handling. Again, both tooling costs and lead times are generally modest.
More Than Just Performance – The Full Value of Custom Optics
While the principal benefit of custom LED optics might seem obvious – optimised performance – there are often many additional ways in which customisation can add value.
For instance, it’s quite common to integrate mechanical features directly into the optic itself, allowing it to interface seamlessly with the product enclosure. This can include the addition of seals, mounting features, or alignment aids – particularly useful in exterior and ruggedised applications such as street lighting, explosion-proof fixtures, automotive lighting, and marine environments.
Another subtle but highly effective customisation is the creation of LED optic arrays. These can reduce manufacturing and assembly costs while ensuring precise inter-optic alignment. Arrays are especially valuable in high-output or directional lighting applications like stage and theatre lighting, searchlights, and urban streetlighting.
They’re also widely used in non-human vision systems – for example, in ultraviolet curing (used for printing, adhesive bonding and stereolithography), as well as infrared illumination for machine vision inspection, night vision in security systems, automatic number plate recognition, and even cosmetic or therapeutic applications such as skin treatment.
Final Thoughts
So, whatever your LED application, we strongly encourage considering the many benefits of LED optic customisation – particularly when optics are designed as a fully integrated part of your overall product. To whet your appetite, here are just a few of the many innovative applications we’ve had the privilege of working on over the years:
Borosilicate glass lens manufactured in open mould with edges ground and polished
Application: Helicopter landing deck pixel in green or amber, part of a highly efficient LED helideck system for offshore use.
Benefits: Meets CAA CAP437 standards for helideck lighting. Operates in extremes of temperature (+/-50C). Extremely tough: withstands helicopter landing pressure, aviation fuel spillage, marine environment.
Single LED ultra-wide light dispersion lens
Application: Illumination of road bollards.
Benefits: Extremely high system efficiency is achieved in combination with low-cost high-reliability passive control electronics. The optic also incorporates ingress protection capability.
Ultra-narrow beam optic for single high-power LED
Application: High-end architectural downlights.
Benefits: Narrow beam width, high beam homogeneity, negligible colour separation, small physical size.
Full multi-optic optical system solution comprising plastic primary lens and aluminium diffused reflector
Application: Class-leading high-power commercial downlight.
Benefits: Class-leading system efficiency, low glare, ‘squared’ illumination. Protected by Forge patents in UK, USA, and Germany.
6-part collimator array for use with blue/violet LEDs
Application: Huge-array LCD-screen-type stereolithography 3D print resin curing.
Benefits: High collimation efficiency enables low 3D-print pixel size due to reduced inter-pixel crosstalk. 6x array provides economy of system manufacture due to ease of assembly.
Miniature highly robust optic
Application: Outdoor handrail-housed illuminators with asymmetric beam for covert application in architectural public spaces.
Benefits: High system efficiency, small physical size, extremely robust with high ingress & impact protection ratings.
Small optic from 8x cavity production tool shown on sprue
Application: Architectural wall-wash illumination.
Benefits: Very small size, high quality wall-wash beam with system in very close proximity to wall giving excellent illumination aesthetics (beam colour purity).
Prototype array of high-power ultra-narrow LED collimators
Application: High-reliability high-performance LED searchlight with illumination distances of several km.
Benefits: High optical performance, very high reliability including LED redundancy. Full solid-state professional security grade searchlight for visible and IR target illumination.
15-LED combination optic array providing precision light distribution and full ingress and impact protection
Application: Street & highway lighting.
Benefits: Class-leading system efficiency. Uniquely able to meet the diverse requirements of both street & highway lighting standards in a single modular light engine. Fully integrated ingress & impact protection.
