Learn How Gentex Dimmable Windows Cut Glare Without Taking Away the View

Q Aviation Week: What problems do EDWs solve that mechanical shades can’t?

A Mike Behm: It depends on the user. From a crew perspective, connecting the windows to the flight attendant panel lets them shape the lighting in the cabin and create a mood, such as sunrise and sunset themes. On a plane full of 400 people, one window cracked open, even slightly, changes the lighting for everyone when the crew is trying to let people rest. Crews can control windows by zone and let passengers adjust their own within set limits. And flight attendants don’t have to open and close shades — or reach over sleeping passengers to do so. For passengers, the windows are infinitely dimmable, so they work like sunglasses. At the first or second setting, you can still enjoy the scenery below, just without the blinding glare.

Q: How does the technology work?

A: It’s electrochromic, a chemical-based electro-optical device we’ve spent roughly three decades tuning. When powered, the chemicals absorb visible light and the window turns dark. Remove the power and they clear, returning to their native transparent state. We can tune the coatings and chemistry for different applications. On an airplane, the window has to get dark enough to work as a shade. We’re always pushing to make the transition faster. The flight attendant panel is the main control, passengers adjust at the window, and some premium cabins add controls to the in-flight entertainment screen.

Q: How do the windows deliver on both reliability and safety?

A: The windows have no moving parts and are insulated from both the environment and the passenger, so they’re very durable. Reliability runs eight to 10 times better than a standard pull-down shade, measured in flight hours between failures, an order of magnitude improvement. There’s no doubt the added cost pays itself back through the operational efficiency of the airplane. First-generation 787s are still flying with the Gentex windows installed on them. Fail-safe, or default clear, is paramount too. It’s an actual requirement of certification, because in a fire or another emergency, crew or others need to look outside or inside the aircraft. It matters most for door windows. On the 787, we have a dimmable window in the emergency door, and default clear there is absolutely mandatory.

Q: How do EDWs help with cabin heat?

A: The newest systems pair the window with an infrared rejection film, a heat-management layer that blocks infrared, which is a big source of solar heat. Our windows run coolest in the clear state because they absorb UV light, so most of it never passes through, even when the window is clear. Compared with an open pull-down shade, a clear Gentex window is much cooler. Operators in the Middle East and parts of Asia see tarmac temperatures around 130 degrees in summer, so thermal performance is part of our design whenever we set up a new dimmable window program.

Q: Where does Gentex go from here?

A: We’re working diligently to expand. The 787 has our windows as standard, and the A350 and the 777X, which launches next year, offer them as options. The wide-body market is where we start. That leaves the A330, older 777s and a large fleet where retrofits and off-the-shelf solutions can make integration easier and cheaper. Then there are single-aisle jets. The 737 and A320 families build well over 100 airplanes a month, and the MAX and A321XLR now fly transatlantic and long intra-Asia routes of six to eight hours. Airlines are seeking to harmonize the passenger experience, design, and technology, across routes and aircraft. Between how those airplanes are used and the sheer scale at which they’re built, that’s a huge opportunity for continued growth.

Q: What else is Gentex bringing to the cabin?

A: Cabin lighting is a primary focus for what comes next. We make our own electronics here in Michigan and design our own optics, so we’re well suited to passenger lighting. We’re finally seeing opportunities to prove it, and that’s exciting potential growth for us.

About The Expert 

Mike Behm works with aircraft manufacturers and airlines to expand the use of Gentex electronically dimmable windows across wide-body and single-aisle platforms.