upper and lower supports 94 98 are composed of a carbon fiber composite though other compositions of the supports are possible the upper support 94 has an upper surface 102 and a lower surface 106 that contacts an upper surface 110 of the lower support 98 as shown in the illustrated embodiment the lower surface 106 includes a bearing layer 114 that is intended to reduce friction between the lower surface 106 and the upper surface 110 of the lower support 98 when the upper support 94 is moved with respect to the lower support 98 in the illustrated embodiment the bearing layer 114 is a polyimide laminate that is coupled to the lower surface 106 using a pressure sensitive adhesive in the illustrated embodiment the laminate is kapton u2122 available from dupont when the upper support 94 moves with respect to the lower support 98 any friction that builds up between the supports can interrupt the operation of the electronics that control the operation of the couch 82 and thus minimizing the friction is one of the goals of the invention further when the supports are composed of the carbon fiber composite the friction can cause the creation and build up of carbon dust which can cause problems with couch operation additionally if the surfaces.