Renault-Concept-Car Zoé

Glass Roof Element Development

Under a Starry Sky...
Renault chose the 2005 Geneva Motor Show to unveil its latest concept car, called "Zoé". The small upper-range urban vehicle is designed to provide genuine motoring pleasure. Visitors to the show were presented with a compact, attractive and dynamic model: Zoé features clear-cut lines and rounded forms as well as a luxurious, functional and asymmetrically designed interior that offers three fullsize seats and a voluminous boot. Glass roof panels inlaid with LEDs bring plenty of light into the interior. A further interesting new development is a memory stick that enables drivers to personalise their car: one click will automatically adjust the music, settings and interior ambience to match the taste of the individual driver.

Renault-Concept-Car "Zoé"
Renault entrusted the electronics department of Bertrandt France with designing and producing the glass elements that light up like a starry sky, as well as the corresponding control electronics. The entire development was determined by the innovative interior. The originality of the concept enriched this exciting project and inspired all those involved to come up with numerous new ideas.

The glass elements consist of laminated glass panels that integrate a polyester film with LEDs and four layers of coloured PVB (polyvinyl butyral). The laminated glass is heated in an autoclave for eight hours at 130 °C and under pressure of 15 bar. During this process, the PVB melts and forms a homogeneous combination of the different elements.

This process is made more complex by the fact that all the elements are applied under limited conditions in terms of their usability. For this reason, the development and execution of this cutting-edge technology represented a major challenge.


A poetic touch from Renault’s design department

A control system allows all the parameters for switching the LEDs on and off to be regulated. The two glass panels can be controlled independently of one another and the time delay before they reach their maximum light intensity can be set individually or can be configured via an Ethernet connection in the vehicle.

The system calibration software, which was developed by Bertrandt France, allows the different parameters to be adapted to the surroundings. For example, it makes it possible to predefine several configurations that offer the user a selection of different lighting sequences. The system also offers interaction between the user and the lighting ambience in the interior. For example, it can create a link between the light intensity and the speed of the car or allow the lighting of the glass panels to be automatically activated by external parameters.

Future perspectives

The positive response from the media encouraged the Renault design team to consider developing transparent conductors to the LEDs. The engineers are currently working on this idea and the results of their work may well be seen in one of the next concept cars from Renault.