The Effect of Polarizing Filters on LED Lights

Polarizing filters reduce glare.

Light waves polarized in many random directions cause visual difficulties such as glare. Polarizing filters send light waves in one direction, thereby reducing these difficulties. For LED and other lights, the contrast between objects becomes clearer as a result.

The Facts

Light emitting diodes, or LEDs, have no filament and fit directly into an electrical circuit. As a result, LED lights use less electric power and emit no excess heat. Electricity flows through a path created between a semiconductor anode and semiconductor cathode.

Light

As an electromagnetic wave, light oscillates in three-dimensional space at different angles. Linear polarization occurs when light waves only oscillate in one direction. LED and many other light sources polarize randomly, which means their light waves oscillate at various angles as time progresses.

Filters

Polarizing filters absorb and prevent light oscillation from all angles except one, essentially allowing light to pass through while reducing reflective glare and enhancing contrasts. According to the National Forensic Science Technology Center, using polarization filters on LED lights, particularly RGB LEDs, enhances contrasting shades well enough to distinguish stains that otherwise blend into the stained materials, such as blood on leather.

References

• National Forensic Science Technology Center: Visualization of Bloodstains on Dark Surfaces using Polarized Light
• Holiday LEDs: How Do LED Christmas Lights Work?
• Edmund Optics: Successful Light Polarization Techniques
• University of Colorado at Boulder: Polarizing Filters
• Great Landscapes: How to Use a Polarizing Filter

Resources

• NASA: Polarization & Color Filtering Applied to Enhance Photogrammetric Measurements