A light modulator comprising a light-reflective metallized membrane defining a deformable mirror disposed over a semiconductor substrate of one conductivity type in which a matrix array of field effect address transistors are formed, the metallized membrane cooperating with a matrix of floating metallic field plate members disposed on an insulating layer covering the substrate to define an array of air gap capacitors for line addressing by the field effect address transistors. The floating metallic field plates are opaque to light and prevent photocharge generation in the active regions of the matrix array of field effect address transistors. The metallized membrane is spaced from the field effect address transistors and the metallic floating field plates by an upstanding semiconductor grid structure which is formed on the insulating layer of the semiconductor substrate and defines gate electrodes for the address transistors. The metallized membrane is mounted on the upstanding semiconductor grid structure by molecular bonding to the contact members disposed over the semiconductor grid structure. The metallized membrane is formed of a polymer of nitrocellulose as a flexible carrier layer on at least one surface of which is disposed a thin metallic coating providing a light reflective surface. Each transistor in the array of field effect address transistors is line-addressable, and the metallized membrane in each cell of the matrix array of air gap capacitors is deflectable inwardly toward the substrate in response to the signal on the address transistor corresponding thereto. Should a potential above a predetermined magnitude be placed on an individual air gap capacitor, the metallized membrane will transfer charge to the floating field plate and return to zero deflection. The floating field plate thereby not only acts as a light-blocking layer, but also prevents voltage-induced collapse of the metallized membrane to the surface of the semiconductor substrate.