Patent ID: 6097355
Filing Date: 2000-08-01
Classification: H01J,H04N

Abstract:
A method of calculating beam landing errors in an electronic display device having color phosphor elements, and electron guns to generate electron beams to impinge on corresponding phosphor elements, said method comprising the steps of:(i) generating a magnetic field having a first magnitude to deflect an electron beam relative to the corresponding phosphor element on which said electron beam is to impinge and measuring the intensity of light emitted by said phosphor element as said electron beam impinges thereon;(ii) reversing the polarity of said magnetic field and repeating step (i) thereby to measure at least two different light intensities influenced by each polarity magnetic field of said first magnitude;(iii) changing the magnitude of the magnetic field to a second magnitude and repeating steps (i) and (ii) thereby to measure at least two different light intensities influenced by each polarity magnetic field of said second magnitude;(iv) approximating the at least two different light intensities influenced by the magnetic fields of said first magnitude with a first straight line and approximating the at least two different light intensities influenced by the magnetic fields of said second magnitude with a second straight line and determining an intersection point of said first straight line and said second straight line;(v) generating a magnetic field having a magnitude corresponding to said intersection point and measuring the intensity of light emitted by said phosphor element as said electron beam impinges thereon; and(vi) calculating a beam landing error using a characteristic of said phosphor element and at least some of said measured light intensities and corresponding magnetic field magnitudes.