Flat-panel picture display device with spacer means adjacent the display screen

A display device comprising an envelope, including a surface bearing a luminescent screen having a multiplicity of predefined areas, and electron source means for selectively energizing respective ones of said predefined areas to produce an image, characterized in that said display device comprises:

• a. at least one electron transport duct defined by at least one wall surface comprising a material having a predetermined secondary emission coefficient;
• b. electron producing means arranged for providing electrons in the at least one duct;
• c. means for establishing a predetermined electric field within the at least one duct to effect production of an electron current by secondary emission from said material;
• d. wall means having output apertures disposed in communication with said predefined screen areas and the at least one duct;
• e. a supporting spacer arranged between the luminescent screen and the wall means and including a plurality of openings for permitting electrons to pass from the output apertures to the predefined areas of the luminescent screen;
• and
• f. selection means for selectively effecting extraction of electron currents from the at least one duct for propagation through said apertures and toward said screen.

A display device comprising an envelope including a surface bearing a luminescent screen having a multiplicity of predefined areas and means for selectively energizing respective ones of said areas to produce an image, characterized in that said display device comprises:

• a. electron emitting means;
• b. at least one electron transport duct which has an electron-receiving portion in communication with the electron emitting means, has a plurality of output apertures, and has an inner surface which is formed, over a substantial length of the duct, from an insulating material having a secondary emission coefficient which is greater than one for a predetermined range of electron energies;
• c. means for producing within said duct an electric field with a predetermined field strength for effecting the transport of electrons from the electron-receiving portion to the vicinities of the output apertures by way of electron interactions with said inner surface of insulating material at energies within said predetermined range;
• d. selection means for selectively effecting the extraction of electron currents from the output apertures;
• and
• e. a supporting spacer arranged between the luminescent screen and the at least one electron transport duct and including a plurality of openings for permitting electrons to pass from the output apertures to the predefined areas of the luminescent screen.