Thermal deformation of a tension mask and beam landing shift for a perfectly flat CRT under localized heating

Thermal deformation of a tension mask under localized heating was analyzed using the finite element method. Landing shift of the electron beam could b e predicted based on these analysis results. In CRT, landing shift of the e lectron beam due to thermal deformation of the tension mask made the color purity of the screen worse. In order to get the final results of thermal de formation, the tensile force within the mask and the welding processes betw een the rail and the extended mask had to be analyzed sequentially. Then, t hermo-elastic finite element analysis was performed on every part inside th e CRT including the tension mask. The analysis showed that thermal radiatio n was the main heat transfer mechanism. Because the tension mask has numero us slits, it was efficient to model it as a shell without slits. And the ef fective thermal conductivity and effective elastic modulus were introduced and calculated. From the displacement analysis results of the tension mask, landing shift of the electron beam could be predicted, Experiments were al so performed to confirm our analysis results. Temperature distributions and beam landing shift of the tension mask were measured and the results were in good agreement with those of analysis.