In our backlighting blog series, we have discussed how to approach a backlighting project and reviewed two popular backlighting technologies – discrete LEDs and light guide film. In this blog post, we will be focusing on the third backlighting technology – fiber optic weave.
What is fiber optic backlighting technology?
Fiber optic technology utilizes a bundle of thin optic fibers that transport light from a single LED to a large surface. Made of acrylic, every individual optic strand is thin, pliable, and extremely durable. However, it should be noted that the LED used is always a bullet LED, which requires a printed circuit board or copper flex circuit as a base. Bullet LEDs cannot be mounted directly on printed membranes.
Advantages of fiber optic backlighting technology
Fiber optics are often integrated in tandem with discrete LEDs, where surface-mount LEDs are used for indicator lighting and fiber optics are utilized to light up the larger area, including icons, texts, patterns, or graphics. As this backlighting technology requires only one LED to illuminate the entire assembly, the power consumption is fairly low.
Given the working mechanism of fiber optics, the color of the lit area or assembly is dictated by the color of the bullet LED. RGB bullet LEDs can be employed to achieve a wide array of color options. Lighting up different sections with different colors can be achieved by utilizing separate layers (separate optic bundles) and using desired colored LEDs as the light source. Alternatively, you can also use a white bullet LED and regulate the colors through the printed graphic overlay.
The main benefits of fiber optic include –
- Ability to illuminate large surfaces with a single bullet LED
- Low power consumption
- Minimal impact on tactile feedback over metal domes
- Mid-range price point
Limitations of fiber optic backlighting technology -
While using a single LED is one of the biggest advantages of a fiber optic technology, it may not be bright enough to illuminate a very large area, especially if the device is primarily used in ambient light. It may also be challenging to light different areas with different colors. This issue can be addressed by configuring more than one fiber optic bundle in the design. However, integrating multiple bundles often translates to increased cost.
While we continue to see this backlighting technology in several user interfaces, we anticipate that it may soon give way to thinner backlighting solutions as devices become smaller and lighter.
To see how a fiber optic backlighting technology works, watch our short video below.