(19)
(11) EP 0 055 331 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
18.05.1983 Bulletin 1983/20

(43) Date of publication A2:
07.07.1982 Bulletin 1982/27

(21) Application number: 81107584

(22) Date of filing: 23.09.1981
(84) Designated Contracting States:
DE FR GB IT

(30) Priority: 31.12.1980 US 221695

(71) Applicant: International Business Machines Corporation
 ()

(72) Inventors:
  • Hevesi, Joseph Francis
     ()
  • Kambic, Stanley Frank
     ()
  • Kluepfel, Joseph Bruno
     ()
  • Schmidt, Frank John
     ()
  • Van Duynhoven, Thomas Jerome
     ()

   


(54) Method of trimming thin metal resistors


(57) A thin metal film resistor (15) of a capacitative graphic tablet is trimmed to make the resistor linear within about 0.25%. Alternating voltage is applied along the resistor by a source (40). The resistance of the resistor is measured at discrete points by a capacitative probe (34) and the resistance readings are stored in a data processor (45). A profile is calculated in the processor from the stored readings and a trim operation is made by an electro-erosion apparatus.






Search report