Cavity resonance absorption in ultra-high bandwidth CRT deflection structure by a resistive load

An improved ultra-high bandwidth helical coil deflection structure for a cathode ray tube comprising:

• a) a first metal member having a bore with metal walls and a central axis therein, said metal walls establishing a first ground plane;
• b) a second metal member coaxially mounted, with respect to said central axis, within the bore of said first metal member and establishing a second ground plane;
• c) a helical deflection coil coaxially mounted, with respect to said central axis, within said bore and spaced between said two ground planes;
• and
• d) a resistive load coaxially mounted, with respect to said central axis, in an end of said bore and electrically coupled between said first and second ground planes to terminate one end of a coaxial line established by said first and second ground plane members to thereby inhibit cavity resonance in said structure, said resistive load having an impedance substantially equal to a characteristic impedance of said coaxial line.

An improved ultra-high bandwidth helical coil deflection device for a cathode ray tube comprising:

• a) a metal housing having a cylindrical bore therein with a central axis, said bore having walls establishing a first ground plane;
• b) a metal member coaxially mounted, with respect to said central axis, in said bore and establishing a second ground plane;
• c) a helical deflection coil coaxially mounted, with respect to said central axis, within said bore and spaced between said two ground planes, said helical coil having first and second ends which are electrically coupled to respective electrical connectors mounted to said housing;
• and
• d) a resistive load comprising a carbon film coaxially mounted in an end of said bore between said first and second ground planes and beyond one of said first and second ends of said helical coil to terminate one end of a coaxial line established by said first and second ground plane members to thereby inhibit cavity resonance in said structure, said resistive load having an impedance substantially equal to a characteristic impedance of said coaxial line.