Abstract: Apparatus and methods for system and method for testing and aligning a CRT which can sequentially perform all of the tests needed to precisely align the CRT and provide real-time feedback for operator adjustments. The system can integrate each of the measurements and automatically verify measurements previously performed as required. An improved color CCD camera is also provided which can maintain focus irrespective of variations in the thickness and glass curvature of the CRT screen. Further, photodiode optical filter and lens assemblies and wobulator assemblies can be incorporated into the system to further improve the testing and aligning of the CRTs.

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 require a magnetic field to be generated to deflect an electron beam relative to the corresponding phosphor element on which the electron beam is to impinge. The intensity of light emitted by the phosphor elements in the measurement area is measured as the electron beam impinges thereon. The polarity of the magnetic field is reversed and the above step is repeated. Thereafter, the magnitude of the magnetic field is changed and the above two steps are repeated thereby to measure at least two different light intensities resulting from electron beam influenced by each polarity magnetic field. The at least two different light intensities resulting from electron beams influenced by each polarity magnetic field are then approximated with straight lines and an intersection point of the straight lines is determined.