A transparent chromogenic panel in which color changes are selectively
effectable over predefined areas comprises a pair of facing glass
substrates each covered with a conductive layer divided into individual
energizeable areas each provided with as set of busbars. An electrochromic
electrode layer overlies at least one of the conductive layers. An
insulating adhesive sealant spaces apart the substrates and insulates the
busbar sets from each other and from exposure to the electrolyte and the
electrochromic layer, so that each busbar set may be individually
energizeable to effect a color change through a respective one of the
individual areas. A passive layer is advantageously superimposed over one
of the substrates, its color being chosen so that the color and the
transmissivity of the passive layer accommodates the range of color change
and transmissivity of the electrochromic layer to maintain the transmitted
color of the panel in a warm or neutral shade.