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Why Light Guided Film is preferred for Backlighting Membrane Keypads

Here are a few ideas to help develop your backlighting solutions. Light Guided Film offers excellent results while staying cost-effective.

LGF Light Guided Film animation - membrane keypads membrane switches membrane keyboards graphic overlay

Why Light Guided Film is preferred for Backlighting Membrane Keypads

Product designers are under tremendous pressure these days to fulfil customer needs with rapidly changing technology and demanding product specifications. Some of the challenges are to make a product look great while adding value to the end-user in functionality and user experience. Our customers want to balance the aesthetic needs of new products against a cost-effective solution. Here are a few ideas to help develop your backlighting solutions.  Light Guided Film (LGF) will supply excellent results while staying within the project’s cost margins.

1. Lower Manufacturing Costs

Light Guided Film with LED-driven backlighting regularly offers lower costs than alternative forms of backlighting. LGF overcomes the need for expensive diffusers and light pipes. Often more traditional types of backlighting are more challenging to route from the PCB to the display in assembly. They may require dedicated mould tooling, which can be expensive. Therefore, the reduction of LGF component complexity makes assembly much more straightforward. This simplicity of design makes the manufacture of LGF Backlighting more affordable and decreases the products construction time.

2. Improved Illumination Options

Light Guide Film is a cost-effective solution when you need to illuminate either the whole membrane keypad or just individual key, switch or status icons. LGF backlighting can often be integrated into the keypad construction directly over key positions. The light transmitted is generally of uniform distribution and can be restricted to dedicated areas with no light bleed. Whereas using a light diffuser may not achieve an even spread of illumination. Beneficially, keys and indicators can be designed to change colour on an operation, with the incorporation of RGB LEDs adding a greater range of illumination options.

3. Flexible Design Options

LGF backlighting provides increased flexibility for product designers since Light Guide Film is slim and highly durable. With the total construction depth of a keypad typically only being 1.6mm thick, the possibilities for a more functional and creative product increases. One such benefit of applying LGF to your HMI design is that you gain the ability to mount the controller PCB further away from the actual user interface.

4. Increased Reliability

One of the issues with other backlighting technologies is that they can have a limited life span. Plus, when traditional backlighting ages, the intensity of the light source can start to dim. Adding a backlighting system to your product can be a critical feature of the equipment. As an integral part of your device, it seems logical that your product looks and performs flawlessly. Therefore, the thought of refitting these interfaces with a replacement backlighting system after some time seems pretty costly and inconvenient. The life expectancy of light guided film is far longer than the other alternatives, usually over 100,000 hours. Finally, as previously mentioned, LGF will display a consistent, balanced illumination over its entire operational life. No fading!

5. Eco Friendly

Traditional backlighting is guilty of converting most of the energy into heat. Subsequentially, this wastes as much as 75% of the power that passes through each bulb. Consequentially, as this energy converts into infrared heat radiation, neighbouring parts may become damaged over time. Every bit of energy that is converted into light and not wasted as heat, makes your design more energy-efficient and provides an eco-friendly benefit.

RH LGF Light Guide Film cross section diagram

Examples of Typical Applications:

  • Medical
    • Medical monitoring and drug delivery systems
    • Ventilators and critical care monitors
    • Nurse call systems
    • Hospital bed controls
    • Centrifuges and lab equipment.
  • Security and Defence
    • Military control systems
    • Rugged display user interfaces
    • Door entry systems
    • Marine navigation systems
  • Industrial Control
    • Instrumentation and user interfaces.
  • Automotive
    • Vehicle cab controls
    • Emergency vehicle control panels
    • Secret-til- lit cluster indicators.
  • Retail
    • Shop windows displays
    • Kiosk user interfaces
    • Point of Sale (POS)

So, when designing your next human-machine interface with rear illumination, please consider using light guided film. This may improve the performance of your device while also saving your budget! LGF can offer a display solution for every product you design in every market sector you can imagine! Call RH on 01264 721450 to discuss how we can help improve the design and illumination of your product.