Industry Insights
Coating Films for “Smart Windows” October 15, 2014 | by Barbara Sies, General Manager, Business Development Manager, Carestream Tollcoating

Window films can be applied for various reasons including privacy, decorative applications, and most importantly energy and light management. Experts agree that up to 20 percent of a typical building’s heat can be lost through windows and doors. Double- and triple-glazed windows and tinting treatments are often used to help minimize this heat loss and lower energy costs.

Window treatments are typically described as passive or active. The passive technologies filter out light without the flexibility to adjust to changes in temperature or light. They block solar energy out even when the temperatures are cool and trap warm air in when outside temperatures are hot. Passive technologies include dyed and reflective films. The reflective films are generally vacuum coated metalized films.

Active or Smart Windows offer flexibility that can be tuned for optimum energy savings. They adapt based on the level of light or heat or by applying an electrical charge. Many of the active technologies can be continuously coated at environmental conditions. There are several types of active windows supported by the application of specially coated films including:

  • Photochromic – shading more light when the sun is bright and less, or none, at low light times.
  • Electrochromic – shading or blocking more light based on an external sensor that applies an electric field to the window.
  • Thermochromic – shading or blocking more light in response to the external window temperature.


smart window films, active window films

Smart windows adjust filtering settings to allow light in or keep it out.

Manufacturing smart window films has some unique challenges. Carestream Contract Manufacturing draws upon its expertise in solvent coating to coat films for architectural windows, sunroofs, rear view mirrors and more. The solutions may contain liquid crystals, nanoparticles or other additives that must be evenly dispersed. To ensure proper functionality of the solution, the mixing method, solution delivery system and filtration must be developed through experimentation.

The coating technique used will be dependent upon several factors including the viscosity and percent solids of the solution as well as the desired coating thickness. Carestream can provide highly uniform coatings, ensuring consistent tinting throughout the finished window. Our clean room manufacturing practices along with our recently upgraded air filtration system help minimize defects down to the micron level. Online laser and camera inspection systems help us monitor coating quality and quickly react to waste issues. In addition, the production coaters have dual coating stations that can either coat a second layer on the same side of the film, or apply a different solution on the back of the film. UV curing and lamination are also available – perfect for when an adhesive layer needs to be applied to the back side of the film.

What if you have only coated small-scale samples? Carestream can help scale-up your process from benchtop to full-scale production. Starting on one of our pilot lines, we can determine the optimum coating and drying conditions while minimizing raw material usage. From here, we move to the production machines to provide film meeting your specifications. Carestream also offers quality and analytical testing as well as defect analysis.

Window manufacturers hoping to benefit from the exponential growth expected in this market will need reliable suppliers who can provide quality-assured films with high-precision coatings. The unique combination of relevant technical knowledge and expertise, quality assurance and state-of-the-art coating facilities makes Carestream a superb partner in coating the films required to make smart windows perform as promised.

Manufacturing smart window films has some unique challenges. Carestream Contract Manufacturing draws upon its expertise in solvent coating to coat films for architectural windows, sunroofs, rear view mirrors and more.

Tollcoating Newsletter Signup