The incorporation of new features and functionality into glazing units can create new applications for which glazing units were not previously thought suitable. Motor vehicle designs, for example, have tended in recent years to employ ever increasing glazed areas, rather than metal or other opaque body panels, in the window and roof area. Designs calling for entirely glazed window and roof areas have been proposed. Such designs, however, call for various passenger compartment features and devices to be provided in new ways. Thus, for example, protection is needed from sunlight glare, formerly provided by opaque vehicle roofs. For this purpose glazing units are known which provide solar load reduction ("SLR") means for preferentially reflecting infrared and other non-visible radiation (preferentially, that is, relative to light in the visible wavelength range). This is particularly advantageous if the glazing unit is utilized as a motor vehicle window or as an architectural window. Reducing the solar energy passing through a glazing unit is becoming increasingly important in architectural and automotive applications for reasons including improved environmental control and energy conservation. Particularly in the case of automotive applications, increased glazed surface area in the upper part of the vehicle body, that is, in the window and roof area, has resulted in greatly increased solar heating of the passenger compartment of the vehicle. Such heating by solar energy generally is referred to as solar load and there is a growing demand for glazing unit which significantly reduce solar load. It is undesirable to handle increased solar load by increasing the size of the motor vehicle air conditioning unit, in view of the overriding need to reduce the size, weight and power consumption of motor vehicle components for increased fuel efficiency. Accordingly, the need to reduce the solar energy load passing through vehicle glazing has become especially critical.
Additional functionality is desireable in glazing units and certain applications will require certain combinations of features. The present invention provides laminated glazing units advantageously incorporating functionality and combinations of functionality well suited to architectural, automotive and other applications. Particular objects and advantages of the present invention will be understood from the following discussions.