(19)
(11) EP 1 469 506 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
03.03.2010 Bulletin 2010/09

(43) Date of publication A2:
20.10.2004 Bulletin 2004/43

(21) Application number: 04252134.4

(22) Date of filing: 08.04.2004
(51) International Patent Classification (IPC): 
H01J 61/72(2006.01)
H01J 7/22(2006.01)
 H01J 61/32(2006.01)
H01J 9/40(2006.01)
(84) Designated Contracting States:
AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IT LI LU MC NL PL PT RO SE SI SK TR
Designated Extension States:
AL HR LT LV MK

(30) Priority: 16.04.2003 HU 0301023
02.01.2004 US 751156

(71) Applicant: GENERAL ELECTRIC COMPANY
Schenectady, NY 12345 (US)

(72) Inventors:
  • Bajnok, Janos
    2040 Budaors (HU)
  • Lukacs, Sandor
    2621 Veroce (HU)
  • Horvath, Andras
    2151 Fot (HU)

(74) Representative: Pedder, James Cuthbert et al
London Patent Operation, General Electric International, Inc., 15 John Adam Street
London WC2N 6LU
London WC2N 6LU (GB)

   


(54) Method for forming cold spot region and discharge lamp with such cold spot region


(57) A method for forming a cold spot region on a discharge tube (2) of a discharge lamp is disclosed In the method, a discharge tube (2) is formed, and a tubular extension (18) is formed on at least one end of the discharge tube (2). The tubular extension (18) has a smaller diameter than the diameter of the discharge tube end. The tubular extension (18) is formed so that a free end of the tubular extension (18) extends away from the end of the discharge tube (2). A reduced thickness portion (36) is formed on the tubular extension (18). The reduced thickness portion (36) is formed as a membrane (38).
A discharge lamp is also disclosed, which comprises a discharge tube (2) with a tubular extension (18) located at an end of the discharge tube (2). The tubular extension (18) has a smaller diameter than the diameter of the discharge tube end, and the tubular extension (18) comprises a reduced thickness portion (36). The reduced thickness portion (36) is a membrane (38), preferably formed of the material of the tubular extension (18).







Search report