cross section side view of a micromirror package 500 showing the laminated layers forming the package substrate and providing a precision reference plane relative to the position of the micromirror device 404 in fig5 portions of the lower package layers 506 have been removed to expose discrete regions of the lower surface 514 of the upper layers 508 the lower surface 514 of the upper layers is the reference plane the reference plane again is the interface between the upper layers 508 and the lower layers 506 forming the package substrate when installed in a display system or other optical system the exposed portions of the reference plane are used to align the micromirror package the package of fig5 provides a more accurate alignment since the alignment features of the display system have direct access to limited regions of the reference plane 516 of the micromirror package 500 this eliminates any variance in the thickness of the upper layers 508 or in the transparent cover 512 in display systems that align to the transparent cover or any variance in the lower layers 506 in display systems that align to the bottom surface of the package in fig5 the only remaining variance between the actual micromirror device and the remainder of the display system is the thickness of the adhesive used to attach the micromirror to the package and any cupping or lack of planarity in the upper surface of the lower layers fig6 is a top view of the micromirror package 602 similar to that shown in fig4 showing the location of the reference plane regions around the package of fig4 fig7 is a perspective view of the micromirror package 602 in fig6 and.