Patent ID: 6507360
Filing Date: 2003-01-14
Classification: G01N,H01J

Abstract:
A method of manufacturing a cathode ray tube, wherein the method includes inspecting a pattern provided on a display screen of or for a cathode ray tube, characterized in that the inspecting process comprises:selecting a camera and an adjustable focal length lens which will provide a sub-image of a portion of the display screen to the camera, fixing the relative positions of the display screen, the camera and the adjustable focal length lens with respect to each other, using at least one rotatable mirror to select the portion of the display screen being viewed by the camera at any viewing instant, rotating said mirror to successive angular positions such that the camera views a corresponding succession of a multiplicity of sub-images of respectively different portions of the display, changing the focal length of the lens to bring the sub-image into focus when the distance from the mirror to the portion of the screen being viewed changes as a result of the mirror rotation, while the mirror and lens adjustment are in a rest state at each respective angular position, obtaining data descriptive of a respective picked-up sub-image in the camera, and applying the respective data of each sub-image to a processing unit.