Abstract: A display device includes an evacuated envelope having a back wall and a plurality of mutually parallel internal support walls. Each of the support walls comprises a separable first and second wall member. Each of the first wall members has a proximal end in contact with the back wall. The support walls are substantially perpendicular to the back wall so that the support walls partition the device into a plurality of channels. A faceplate assembly integral with one surface of the envelope comprises in combination; a viewing faceplate, a mosaic screen, registration blocks disposed on the inner surface of the faceplate beyond the screen, a plurality of second wall members detachably attached to the registration blocks so that each of the second wall members extend between the distal end of a different one of the first wall members and the screen, and a plurality of discrete shadow masks slidably attached to and extending between adjacent ones of the second wall members.