Color picture tube device

Abstract

PURPOSE: To reduce uneven deterioration in a fluorescent substance and to decrease a difference between coloring based on the deterioration and coloring in a non picture area by lighting the no picture area which is not relevant at the outside of a picture display area when a picture smaller than the effective area of a fluorescent screen is displayed. CONSTITUTION: When a picture whose aspect ratio is 3:4 is displayed in the center area of a fluorescent screen 6 whose aspect ratio is 9:16, the entire fluorescent screen 6 is scanned and electron beams B, G, R are made incident even in the outside of the picture display area 9. Since the electron beams B, G, R radiate the entire face of a shadow mask 5, deterioration of the fluorescent substance is caused not only in the picture display area 9 but also in the no picture area 10a and the faster progress of the deterioration in the fluorescent substance in the picture display area 9 caused when only the picture display area 9 is scanned than that at the outside is suppressed. Then the difference of the coloring caused sometimes in the case of displaying the picture on the entire fluorescent screen 6 is not made remarkable. COPYRIGHT: (C)1991,JPO&Japio

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    Publication numberPublication dateAssigneeTitle
    JP-H0830762-AFebruary 02, 1996Nec Corp, 日本電気株式会社Print-of-seal image density converting device