RH provides a wide range of backlighting solutions.
We supply our customers with a comprehensive range of backlighting solutions that provide an excellent option for your Human-Machine Interface (HMI) needs. Backlighting is essential for some customers’ branding or other customers; it is a crucial feature of better device functionality. Therefore, it doesn’t matter if you create a membrane keypad, rubber keypad or capacitive touchscreen interface; backlighting can highlight your product and stand out from the norm. Backlighting is also crucially important in low-light environments adding maximum contrast and consistent edge definition.
The selection of backlighting technology:
- Light Guide Film (LGF)
- LED’s
- Acrylic Edge Lit Tiles
- Electroluminescent (EL)
The benefits of backlighting solutions:
- Aid visibility in low lighting conditions
- Predictive hints to guide user operation
- Operational status and warnings indication
- Enhance the visual appeal of the product
- Increase quality perception
- Branding purposes
Light Guide Film. (LGF)
LGF is a thin film backlighting technology that will direct light produced by side-firing or right-angle LEDs across the area that needs to be backlit. Thus, the advantage of Light Guide Film is that it fabricates into almost any shape. The result provides consistent backlighting across one or more areas within the switch.
Light Guide Film (LGF) has the following potential advantages:
- It has a low profile for incorporation into membrane switches that can not exceed a certain thickness (i.e. small or lighter devices)
- LGF has an impact where the tactile feel of buttons is limited.
- It provides even backlighting across large and small areas. (including applications where the light remains on while the switch is powered.)
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Building up multiple LGF layers.
The use of multiple films can be used within one application to provide discrete backlighting solutions to different graphic features. Other coloured LEDs work to achieve unique lighting effects, whereas white LEDs can light different printed graphics on the overlay.
Light-emitting diodes. (LED)
LEDs are used primarily as indicator lights and are a popular, low-cost, point-source lighting method. Embedded LED’s emit very little heat and come in a variety of colours, including red, yellow, green, blue, white, and bi-colour lamp packages. Depending on the surroundings, various intensities are available. Some LED backlighting solutions are designed especially for viewing in outdoor environments instead of others for indoor use.
Surface-mounted LEDs bonded into our polyester switch construction provide a reliable and cost-effective light source. This construction can use an even greater variety of lamp packages in PCB Membrane Switches and Copper Flex Switches. These can be through-hole soldered, which enhances durability.
Other features of LED backlighting solutions:
- Reliability and long life – typically more than 50,000 hours.
- Low cost.
- Efficient power consumption, operating on low voltages.
- Available in a wide variety of colours, intensities, and lamp packages.
Acrylic Edge Lit Tiles.
Acrylic edge-lit tiles use embedded LEDs to light the surface of the tile. These tiles have a printed dot pattern on the rear face to make the light diffuse evenly. Finally, a unique diffusing film hides the dot pattern on the front of the tile. This pattern results in a bright and even light over a large area using only 1 or 2 LEDs per tile. The addition of more LEDs will increase the brightness and evenness of larger tiles.
Features of acrylic edge-lit tiles include:
- The ability to fit tiles with multiple coloured LEDs or RGB LEDs creates colour-changing effects.
- The option is to embed 2- 3mm tiles into Keypads or use overlays to produce backlit areas. (They are perfect for indicator panels and capacitive switch panels.)
- Fitting multiple tiles to a PCB assembly offers an array that lights individually or in conjunction with a secret lit overlay.
Electroluminescent Lighting. (EL)
EL lamps contain phosphorus, which converts electrical energy directly into light energy. The high efficiency of this conversion minimises power consumption and reduces losses due to heat or Infra-red emissions. EL backlighting devices consequently consume relatively little power under regular operation. They are best suited for low and no light applications where the backlight is not always on.
Some additional features for EL lamps are:
- EL lamps consume very little power
- Provides uniform, balanced backlighting of the entire membrane switch area
- The thin profile and durability make it suitable for most membrane switch constructions
