Method of convergence measurement for a color picture tube and an apparatus therefor
AssigneeTokyo Shibaura Denki Kabushiki Kaisha
InventorsShinichi Uno, Etsuji Suzuki, Ryuhachirou Douji, Mituji Inoue
Life of this patent
Estimating the term…
Abstract
The convergence of a color picture tube is measured by first indicating a prescribed pattern in a reference position on the picture tube. The image of a pattern for each light beam color in the picture tube is picked-up, and then this display position of the pattern is shifted. An image of the pattern in the shifted position is then picked-up for each beam color in the tube which gives a second image pick-up data. The average values of the data obtained from the non-shifted and shifted pattern for each light beam color is used to determine the convergence of the color picture tube.
Claims8
A method for measuring the convergence of a color picture tube, comprising the steps of:
- indicating a prescribed pattern in a reference position on the display screen of a picture tube on which a plurality of light emitting layers emitting light beams of different colors are successively and alternately arranged at regular intervals;
- picking up the image of a pattern for each light beam color from a predetermined position, thereby providing first image pickup data,
- shifting the display position of the pattern on the display screen from the reference position to a shifted position at a distance half the arrangement pitch of the light emitting layers, in the arrangement direction thereof from the reference position;
- picking up an image of the pattern in the shifted position, for each light beam color from the predetermined position, thereby providing second image pickup data;
- and
- calculating the average values of the first and second image pickup data for each light beam color and determining the convergence on the basis of the average values.
A convergence measuring apparatus for a color picture tube, comprising:
- means for selectively generating a prescribed pattern in a reference position on the display screen of a picture tube on which a plurality of light emitting layers emitting light beams of different colors are successively and alternately arranged at regular intervals, and in a shifted position at a distance half the arrangement pitch of the light emitting layers, in the arrangement direction thereof from the reference position;
- image pickup means opposed to the display screen of the picture tube and movable along the display screen, whereby images of the pattern are picked up for each light beam color;
- and
- arithmetic control means for calculating the average values of each light beam color of image pickup data for the patterns in the reference position and the shifted position provided by the image pickup means, and determining the convergence of the picture tube on the basis of the average values.
Dependencies are inferred from the claim text.