An expanding chassis for an imaging unit is provided, the expanding chassis for use in imaging systems having a plurality of imaging units arranged in an array. The expanding chassis comprises a rigid frame for housing a light engine and related circuitry, and for mounting a screen on a front surface of the rigid frame for use with the light engine. The expanding chassis further comprises at least one expandable interface pad on at least one side of the rigid frame. The rigid frame and the expandable interface pad have a combined thermal expansion characteristic that provides an overall expansion in the expanding chassis that substantially matches the expansion of the screen.