A lid (2) for an electronic circuit housing (4) has inner (24) and outer (22) laminated layers that are formed from two different materials, joined to each other and bowed outward from the housing (4) so that the inner layer (24) is under tensile bending stress at the interface between the layers, and...http://www.google.com/patents/US5268533?utm_source=gb-gplus-sharePatent US5268533 - Pre-stressed laminated lid for electronic circuit package
