Fiber Optic Technical Brief
Differerentiate your products with Fiber Optic Back-Lighting
Membrane Switch and Keypad Lighting made easy!
Benefits:
- Uniform lighting over a large area
- Low power, one LED for entire panel
- Long life, essentially no fading
- Low cost, no inverter or complex drivers
- No EMI/RFI
- Durable, Reliable (tested to 5MM cycles)
- Thin (0.013”); superior tactile response
- Design flexibility, easily customizable
How Fiber Optic Backlighting Works:
Sheets of fiber backlighting material are made from either Woven or UniGlo fiber. UniGlo is generally preferred for switches due to its thinness (0.013”).
These fiber sheets are constructed to a specific length and width. The cable (tail) end is bundled into a ferrule and mated to a light source. Typically one layer of fiber is used in conjunction with a backreflector and, if desired, double sided adhesive can be mounted on thetop or bottom.
Light Sources:
- LED colors; Green, Blue, White, Amber, Red.
- 5mm round lamp type LED uses ST-250 clip. Supports up to 400 fibers (4” of panel width)
- 3mm round lamp type LED uses ST-160. Supports up to 135 fibers (1.35” of panel width)
Comparison with Other Technologies
Cable/Source Placement & Routing
Our Applications Engineering team is very creative with routing cables and sources around mechanical constraints.
Secondary Enhancements:
- Dbl sided adhesive with release liner can be mounted on the top or bottom of the panel
- Die-cutting;
a. Holes in the reflector only allow an indicator LED to show through the panel.
b. Holes through the entire panel allow for routing around mechanical elements.
Note that light will not transmit in thefiber downstream of the hole.
c. Shapes and cutouts
- Heat Formed Cable can allow for better routing around mechanical constraints. This may also be accomplished with mechanical elements in the end device (the fiber tail is flexible).
- Randomized Cables; LED dis-uniformities are not transmitted to the panel. Fibers that are adjacent in the panel are specifically ordered so as not to be adjacent next to the LED. This may also be accomplished by proper overlay
diffusion or by reducing the number of fibers attached to one LED.
- Opacify the End and/or sides; prevents stray light from affecting the look of the product.
This may also be accomplished by a bezel or selective printing on the overlay.
- Circuit elements printed on Back Reflector; eg conductive pads for use with a Rubber Keypad.
- Cable Coverings; such as heat shrink or flex wrap to protect the fiber optic cable.
- Multiple panels connected to one LED.
- Multiple colors on one panel; through multiple LED’s or a Tri-Color LED.
Prototyping:
- Typical Lead Time; 4-6 weeks. Faster turnaround can be accommodated if necessary.
- Typical Cost; $1-2k per lot
- Ask for a free non-custom sample that is close to your application.
