Abstract: A cathode ray tube having a glass envelope with a conductive layer covering a portion of the inner surface of the envelope. The major part of the surface covered by the conductive layer is relatively rough to obtain good adhesion of the conductive layer. An electrode within the tube is connected electrically to the conductive layer by a contact spring that presses against a limited region of the conductive layer. The area of the glass surface that is directly behind this limited region is made sufficiently smooth to prevent the contact spring from being held out of engagement with the conductive layer by glass protuberances projecting through the conductive layer and causing arcing between the contact spring and adjacent areas of the conductive layer.