Passion Project 3.3 - Research

Wavelength and Optical Density

Laser Strike Protection Eyewear

Laser Protective Acrylic

Laser Protective Glass

Darkening Methods

PPG Industries Aviation Window Supplier 
       787 Window Technical Sheet
GKN Aerospace Window Supplier
       Boeing 757, 767, 777 

• SPD (Suspended Particle Device)
• Particles are in random patterns without charge
• Dark without charge
• Clear with charge
• On Boeing 787 windows but take time to transition
• 
• Liquid Crystals
• Particles are misaligned but align parallel with charge
• Translucent without charge
• Transparent with charge
• Transition is instant
• 
• Electrochromic Device
• Particles change color with charge
• Clear without charge
• Darken with charge
• Transition is instant
• 

SPD Devices are ruled out because of the time it takes to transition

Further research is needed on whether PDLC or electrochromic windows have the better optical density (OD) and visual light transmission (VLT).
     
If both are similar, electrochromic windows will be preferred because they are clear without charge thus not being an obstruction in catastrophic power loss situations; however, if PDLC has significant advantages, PLDC could still be used due to the reliability of modern backup power units including the APU (auxiliary power unit) or the implementation of a dedicated emergency power unit.