Renault Group

Solarbay opacifying sunroof : Spectacular innovation born from a unique joint-development

14 February 2024
Innovation & technology

As part of the Renaulution strategic plan, Renault has chosen to work with the best in order to offer its customers new innovations on its models. The Solarbay opacifying glass roof, developed in partnership with Saint-Gobain, is one example of this. It was unveiled on Rafale and Scénic E-Tech electric and announced on Symbioz. How did the two companies meet the challenge of integrating an intelligent glass roof capable of opacifying in segments on demand? Patrice Hamel, Director of Vehicle Project Engineering at Renault Group, and Tim Jurkowski, VP Sales Marketing & Project at Saint-Gobain Sekurit, explain.

BY Nicolas Le Boucher

Escape. Take to the road with passengers’s head in the clouds, in a light-filled cabin unobstructed by the sun. The experience aboard Renault Rafale and Scénic E-Tech electric equipped with the Solarbay opacifying panoramic glass roof is unique. Because as well as providing excellent thermal comfort and optimum light levels on board, it protects against the sun by darkening on demand, either in its entirety or in halves, in a fluid movement over nine segments. All in a matter of seconds. The effect is striking, to say the least.

A perfect illustration of the innovations that make Renault models "cars for living", this magical glass roof is the result of an unprecedented joint development project between Saint-Gobain and Renault.

Saint Gobain had the technology we were looking for and was therefore the ideal partner to develop Solarbay! But in fact, we quickly went from partnership to co-development. To better combine our skills!

Patrice Hamel
Director of Vehicle Project Engineering at Renault Group

Demanding specifications for Solarbay

The Solarbay opacifying sunroof uses PDLC (Polymer Dispersed Liquid Crystal) technology,” explains Tim Jurkowski, VP Sales, Marketing, and Projects at Saint-Gobain. Used in the construction industry, this opacification technique is based on the displacement of molecules caused by an electric field. In the car industry, only premium manufacturers have used this technology for opaque glass roofs. Renault is the first generalist manufacturer to do so, adding the function of partial and segmental opacification. "To meet Renault's ambitions for its new models, Saint-Gobain Sekurit took up the challenge of adapting it to the interiors of several vehicles" adds Tim.

Renault Rafale unveils Solarbay opaque glass roof

This was one of the constraints in the engineering specifications drawn up for Saint-Gobain. “Circuitry for sunroof opacification had to be easy to install on a range of vehicles. In addition, we wanted the innovative feature to be rolled out on several new models in succession, what we call the ‘wave effect’. Not to forget we also had a tight schedule,” says Patrice on Renault’s side.

The Solarbay roof can be made opaque in segments on demand

More than meets the eye

While the PDLC opacification technology used in the Solarbay opaque glass roof is undoubtedly the most spectacular for all passengers, the technology used to ensure thermal comfort on board is no less remarkable.

The Solarbay glazed roof uses multi-layered glass for excellent thermal comfort

A special coated glass is used to protect passengers from temperature variations and the "icicle" effect in winter and the "sauna" effect in summer when entering the car. “A first layer, 100 times thinner than a stand of hair, reflects most of the infrared radiation from the sun’s rays. A second layer stops heat from entering the vehicle interior in summer, and from escaping the car in winter,” explains Tim.

The glass is made using nearly 50% recycled glass from scraps that come from automotive glass production. This was an obvious choice to make for Renault and Saint Gobain, two companies actively working towards the energy transition and striving to ensure a better-preserved environment.


A unique joint-development between Renault and Saint Gobain Sekurit

During the Solarbay co-development period, meetings between the various working groups were held one after the other. Dedicated joint teams of more than 100 people worked in agile mode to coordinate the development of the glass roof with vehicle development. The Renault teams work with the vehicle architecture teams to integrate the roof so that it is as large as possible (1,470 x 1,117 mm on Rafale).
As for Saint-Gobain, “the challenge was to keep a close eye on both product development and vehicle development, while respecting Renault’s deadlines and quality requirements,” Tim recalls.
Having a fostered a trust-based relationship and guided by Renault's specifications, Saint Gobain succeeded in developing a discreet control box in the ceiling light to control the opacification manually.

Solarbay is a perfect illustration of Renault's ambition to develop technologies that are useful and accessible to as many people as possible by teaming up with the best.

The Solarbay glass roof is the result of joint development between Renault and Saint Gobain Sekurit