Patent ID: 7148620

Claim:
An image display device comprising: a rectangular face substrate which has an inner surface on which anodes and fluorescent materials are formed and on which a display region is formed which has two parallel sides in one direction and two parallel sides in another direction that is orthogonal to the one direction; a back substrate which forms a plurality of cathode lines which extend in one direction and are arranged in another direction in parallel and have electron sources thereon, and control electrodes which intersect the cathode lines in a non-contacting manner at least inside of the display region, extend in another direction and are arranged in the one direction in parallel, thus forming pixels at intersections with the cathode lines on an inner surface thereof, wherein the control electrodes are formed by arranging in parallel a plurality of mutually independent strip-like electrode elements each having one or a plurality of circular electron passing apertures which allow electrons from the electron sources to pass therethrough to the face substrate side, the back substrate being arranged to face the face substrate with a given gap therebetween; and a sealing frame which is interposed between the face substrate and the back substrate while surrounding the display region in such a way as to maintain the given gap between the face substrate and the back substrate; wherein assuming a diagonal screen size of the display region which is formed on the face substrate as D(mm), the number of pixels which are arranged in one direction as Nh, the number of pixels which are arranged in another direction as Nv, the distance between the electron passing apertures formed in the strip-like electrode elements which constitute the control electrodes as db(mm), the distance between the electron sources and the strip-like electrode elements as Lkg(mm), and an aperture diameter of the electron passing apertures as φG(mm), provided that the aperture diameter φG(mm) is expressed by the following formula (1), D 3 · Nh 2 + Nv 2 - 2 ⁢ db > ( - 0.23 · ln ⁡ ( db ) + 0.49 ) · Lkg + 0.02 · ln ⁡ ( db ) + 0.125 ( 1 ) the following formula (2) is established, (0.46·ln( db )+2.5)· Lkg +0.006·ln( db )+0.04 ≦φG ≦(−0.41·ln( db )−0.68)· Lkg +0.014·ln( db )+0.14.5 (2).