Integration of optical element in insulated glazing

#The present application is the national stage of International Application No. PCT/EP2009/055543, filed on May 7, 2009, the contents of all of which are hereby incorporated by reference.

#This invention generally relates to a method of integrating an optical element in an insulated glazing unit. More particularly, the invention relates to an optical element having a plurality of perforations and a non-perforated area.

#Although large glass facades improve the architectural appearance of a building, a general disadvantage is overheating of the building caused by excessive solar transmittance of the facade. To solve this problem either air conditioning or solar shading, or a combination of the two, must be used. One of the primary motivations for the increased emphasis on solar shading has been governmental regulations (combined with a rise in energy prices) which require new buildings to be more energy efficient.

#The above and/or additional objects, features and advantages of the present invention, will be further elucidated by the following illustrative and non-limiting detailed description of embodiments of the present invention, with reference to the appended drawings, wherein:

#FIG. 1 shows examples of how an optical element functions.

#FIG. 2 shows graphs of the effective G-value for an optical element.

#In the following description, reference is made to the accompanying figures, which show by way of illustration how the invention may be practiced.

#FIG. 1 shows examples of how an optical element functions.

#In prior art optical elements or solar cells that are integrated between two glass panes are fully laminated over the entire surface. The laminate will fill the perforations in the optical element. When the optical element is not laminated, the perforations in the optical element are not filled with adhesive such as resin, but are filled with air or the gas used to fill the insulated glazing unit, and the angle of the light inside the perforations is the same as the light angle on the outside of the window, since the refractive index is the same. Thus, when the solar angle is large, the light coming through the perforations will have a large angle, see FIG. 1a). If on the other hand, the perforations are filled with an adhesive material such as a resin or polymeric material, which has a refractive index that is higher than for air, the angle of the light in the perforations will be smaller than the solar angle, see FIG. 1b). This can clearly be seen from Snell's law below. The result is that light coming from large angles, such as in the middle of the day, can be transmitted through the holes that are filled with adhesive such as resin due to the reduction in the angle. For a similar non-laminated optical element the light would be reflected off or absorbed by the optical element. Hence, by using a fully laminated optical element the optical element will allow for passage of light from almost all possible solar angles compared to a non-laminated optical element that would only allow for passage of light for small or medium size solar angles.