48.1: Vibration Prevention Technology in Jumbo Flat CRTs of Tension Type Iron Mask

A decent technology to solve the microphony phenomenon in the tension type jumbo CRTs of iron shadow mask has been developed. Starting from the relation between mask tension and its vibration amplitude and the relation between necessary beam‐landing margin and guard band, the minimum amplitude required to prevent an observer from recognizing beam‐mislanding is calculated. Various types of tension distribution and their corresponding mask amplitude response were analyzed and tested. So‐called the ‘Flat‐U’ type tension was resulted to be the tension distribution for minimum amplitude and doming suppression in association with an appropriate mask pattern design, we could successfully meet the set‐maker's microphony requirement.