(19)
(11) EP 0 068 111 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.05.1983 Bulletin 1983/19

(43) Date of publication A2:
05.01.1983 Bulletin 1983/01

(21) Application number: 82103884

(22) Date of filing: 05.05.1982
(84) Designated Contracting States:
BE CH DE FR GB IT LI NL SE

(30) Priority: 30.06.1981 US 279281

(71) Applicant: International Business Machines Corporation
 ()

(72) Inventor:
  • Piggin, Bruce Paul
     ()

   


(54) Cathode structure and method of making the same


(57) ositive photoresist technology is used on a sapphire substrate (7.1) carrying a patterned metallization layer (11.1) to expose areas (41.3, 41.4) of metallization within delineated apertures in the photoresist. Into these apertures needle-shaped triple carbonate particles (50.3, 50.4) are deposited cataphoretically normal to the metallization areas to form electron emissive areas. A further layer of photoresist is deposited to cover these areas and the first layer of photoresist and exposed through oversize mask so as to leave photoresist as encapsulation material (48.13, 48.14) covering the top and sides of the electron emissive material.
The encapsulated planar cathode structure is inserted into a multibeam cathode ray tube and heated so as to remove the encapsulation material.






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