COLOR PICTURE TUBE DEVICE

PURPOSE:To concurrently and easily focus and concentrate electron beams and sufficiently exert the performance of a large-diameter electron lens by specifying the length from the screen side end of the first electrode to the screen side end of the second electrode against the opening diameter of the second electrode. CONSTITUTION:The length l8 from the screen side end GD7T of the first electrode GD7 to the screen side end of the second electrode GD8 is set to 20-70% against the opening diameter d8 of the second electrode GD8. A large electron lens ML is formed between the first cylinder electrode LCY7 and the second cylinder electrode LCY8 passing three electron beams BR, BG, and BB and a conducting film on the inner face of a neck, and individual electron lenses AL1-AL3 for a plate-shaped electrode ECD independently passing three beams BR, BG, and BB are formed in the region of the lens ML. The aberration of the large electron lens ML is offset, the three electron beams BR, BG, and BB on a screen are similarly focused and concentrated at one point. The performance of the common large-diameter electron lens ML is sufficiently exerted, and the electron beams can be focused on the screen surface in the optimum convergence state and the optimum concentration state respectively.