公开(公告)号：NO941869D0

公开(公告)日：1994-05-19

申请号：NO941869

申请日：1994-05-19

Applicant: IBM

Inventor： JACKSON FREDERICK S ,  LEAVER DAVID ,  KNOX ANDREW RAMSAY ,  BEETESON JOHN

IPC: G09G1/00 ,  H01J20060101 ,  H01J15/04 ,  H01J29/00 ,  H01J29/06 ,  H01J29/98 ,  H04N3/16 ,  H04N9/29 ,  H01J

Abstract: A cathode ray tube display having reduced electric field emissions comprising a cathode ray tube 100, an element 200 for detecting modulations in the final anode voltage of the CRT, the signal not being directly dependent on the deflection driving means 115. A matching network 205 provides phase and gain correction to the signal from element 200, amplification means 210 receives the signal from network 205 and an emission means 215 radiates a cancelling electric field dependent on the modulations detected by said element 200.

公开(公告)号：NO914254L

公开(公告)日：1992-05-29

申请号：NO914254

申请日：1991-10-30

Applicant: IBM

Inventor： BEETESON JOHN ,  SMITH KENNETH GEORGE

IPC: H01J29/76 ,  H01J29/00 ,  H04N9/29

Abstract: A display comprising a cathode ray display tube (1) having an electromagnetic deflection yoke (2) is described. A pair of first deflection coils (7,6) are located symmetrically about the longitudinal axis of the tube (1) on opposite sides of the yoke (2) for producing within the tube (1) a first magnetic deflection field. A pair of second deflection coils (8,20) are similarly located symmetrically about the longitudinal axis on opposite sides of the yoke (2) for producing within the tube (1) a second magnetic deflection field at right angles to the first deflection field. The display is further provided with a pair of first cancellation coils (4,3) connected to the first deflection coils (7,6) for producing a first cancellation field which tends to cancel a first stray field produced by the first deflection coils (7,6). Support means (10,11) secure the first cancellation coils symmetrically about the longitudinal axis. The display additionally comprises a pair of second cancellation coils (50,32) coupled to the second deflection coils (8,20) for producing a second cancellation field which tends to cancel a second stray field produced by the second deflection coils (8,20). Further support means (51,52) are provided for positioning the second cancellation coils (50,32) symmetrically about the longitudinal axis in such a way that a plane containing a second cancellation coil (50) is perpendicular to any plane containing a first cancellation coil (4). Preferably, the display also comprises control means (64) for generating a predetermined cancellation current in the second cancellation coils (50,32) in response to a particular second deflection current in the second deflection coils (8,20).

公开(公告)号：NO914254A

公开(公告)日：1992-05-29

申请号：NO914254

申请日：1991-10-30

Applicant: IBM

Inventor： BEETESON JOHN ,  SMITH KENNETH GEORGE

IPC: H01J29/76 ,  H01J29/00 ,  H04N9/29

CPC classification number: H01J29/003 ,  H01J2229/0015