Variable angle photometric characterization of a laminated glass embedding a lamellae system

Glazing units containing sunshading devices (vertical blades, roller shutters, Venetian blinds, etc.) are available on the market nowadays. These products are roughly divided into two families: double-glazed units with automatically controlled devices in the interspace and monolithic glasses embedding fixed devices. The luminous and solar behaviour of the incorporated sunshading devices is intentionally strongly dependent on the position of the sun in the sky, and therefore the optical characterization of this kind of advanced glazing requires transmittance and reflectance measurements as functions of at least one angular coordinate. In this paper a lamellae system embedded in a plastic matrix and sandwiched between two glass sheets is considered. Transmittance and reflectance of the sample computed from the geometrical parameters of the lamellae system are compared to the corresponding values measured with global and bidirectional variable angle measurement systems. As an example of application of the obtained data in real conditions, the laminated glass containing the lamellae system closes the window of a room and daylighting inside the room is evaluated.