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HOW TO ADD ILLUMINATION WITHOUT COMPROMISING YOUR PLASTIC ENCLOSURE’S IP RATING

Machined enclosures for LED backlighting

BENEFITS OF LED LIGHT PIPES

Light pipes – also known as light tubes or light guides – can be extremely useful. These handy transparent plastic rods or optical fibres are an efficient and cost-effective way to carry light from a PCB-mounted LED to an indicator panel.

They enable designs to be more compact – reducing manufacturing costs. They’re perfect for devices that require multiple indicators. They provide clear and clean status indication without the need for solder or crimped terminations.

Light pipes operate on the principle of total internal reflection: the material and shape are designed to minimise light loss, resulting in optimal brightness at the output end. On this basis, they don’t need to be conductive – eliminating the risk of short circuits due to pinched wires. So far so good. But there are some downsides…

DISADVANTAGES OF LED LIGHT PIPES

The first downside is that – in reality – there can still be some light loss; this can affect the brightness of the output. The second is that the LED and the target area must be aligned properly for best performance.

But it’s the third downside that can often prove to be the biggest headache for designers: watertightness. When it comes to waterproofing, light pipes can present a challenge. Their enclosure exit points can allow water ingress if not sealed correctly.

Ensuring a tight seal around these exit points is crucial. In theory, light pipes can be designed to meet specific Ingress Protection (IP) ratings by integrating them with gaskets or sealants that prevent moisture and particulate ingress.

However, this can be challenging in practice – especially if a proliferation of light pipes is required or the IP rating needs to be a higher one to cope with particularly harsh industrial and/or outdoor environments.

Fortunately, there is an alternative…

Enclosures with LED light pipes

PARTIAL BACKLIGHTING WITH INGRESS PROTECTION

Light pipes need an aperture through which to transmit light. And as discussed, that creates sealing issues. So OKW has an alternative that allows light to be transmitted through an enclosure – while maintaining ingress protection in accordance with the housing’s designated IP rating.

Enclosures can be custom machined to create light-permeable indentations. They are not apertures. Instead, they are a reduction in the thickness of the enclosure wall – thin enough to allow light to pass through but thick enough to keep out water and dust.

Importantly, the machining is done in such a way that it has no effect on the enclosure sealing requirements. Nor does it compromise the IP rating: the enclosure will still be waterproof in the conditions for which it was tested and certified.

And because the machining is done from the inside of the enclosure, you won’t see the indentations from the outside. The finished result is what appears to be an ‘invisible’ group of lights. They emit a soft and subtle glow when illuminated – but disappear from view altogether when not.

Depending on your requirements, you can dispense with light pipes altogether. Instead, you simply mount the board with the LEDs immediately beneath the indented surface. It’s a smart, simple and attractive solution that adds extra visual cachet.

SMART-PANEL enclosures machined for LED backlighting

SPECIFY SMART-PANEL WITH INDENTATIONS FOR BACKLIGHTING

Elegant SMART-PANEL enclosures for modern building control systems are a prime contender for this new backlighting solution. The ‘only when illuminated’ visibility of the LEDs perfectly complements the discreet aesthetics of these modern wall-mount enclosures.

SMART-PANEL is designed to fit standard flush-mount or cavity wall boxes, making it a popular choice for building services systems, smart home electronics, IoT/IIoT, offices, wireless communications, measurement/control, medical, laboratory and security technology.

Backlighting looks great on SMART-PANEL because it’s beautifully understated – and because the enclosures are moulded from gleaming  traffic white (RAL 9016) ASA+PC. It’s a sophisticated look, especially if you use the lighting to display numbers or letters.

View the SMART-PANEL range >>

Customised plastic enclosures

CUSTOMISATION SERVICES

Machining of indentations for backlighting is just one of many customisation services offered by OKW. Our CNC machining work covers a wide range of milling, tapping, engraving, drilling, countersinking and stamping.

Other customisation services include lacquering (now with an even wider choice of colours), printing of legends, logos and graphics, laser marking (perfect for sequential numbering, barcodes, QR or DataMatrix codes), decor foils, special materials, EMC shielding and installation/assembly of accessories.

View machining and customisation services >>

GET EXPERT ADVICE ON ENCLOSURE BACKLIGHTING

Contact OKW for technical advice on specifying electronic enclosures with backlighting. Don’t forget to request a sample and/or register for 3D models  (X_T, STP, SAT files).