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公开(公告)号：DK0487796T3
公开(公告)日：1995-12-18
申请号：DK90312872
申请日：1990-11-27
Applicant: IBM
Inventor： SMITH KENNETH GEORGE , BEETESON JOHN
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).
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公开(公告)号：GB2273230A
公开(公告)日：1994-06-08
申请号：GB9225237
申请日：1992-12-02
Applicant: IBM
Inventor： BEETESON JOHN STUART , SMITH KENNETH GEORGE
Abstract: A cathode ray tube display comprises a cathode ray tube display screen 100. A drive circuit 20, 30, 40, 50 generates drive signals for producing a raster-scanned picture on the screen as a function of one or more input signals. One or more of the drive signals also generate a stray electric field that radiates from the display. The display further comprises a cancellation circuit 60, 70, 80, 90 connected to an emitter 120. In operation, the cancellation circuit 60, 70, 80, 90 generates a cancellation signal as a function of said one or more of the drive signals. The emitter 120 radiates a cancellation electric field in response to the cancellation signal to cancel or at least reduce the stray electric field.
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公开(公告)号：NO914254D0
公开(公告)日：1991-10-30
申请号：NO914254
申请日：1991-10-30
Applicant: IBM
Inventor： BEETESON JOHN , SMITH KENNETH GEORGE
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).
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