PRECISION-IN-LINE (P.I.L.) COLOR PICTURE TUBE
This tube as the name suggests has three guns which are aligned precisely in a horizontal line. The gun and mask structure of the P.I.L. tube together with yoke mounting details are illustrated in Fig. The in-line gun configuration helps in simplifying convergence adjustments.
As shown in the figure color phosphors are deposited on the screen in the form of vertical strips in triads. (R, G, B) which are repeated along the breadth of the tube. To obtain the same color fineness as in a delta-gun tube the horizontal spacing between the strips of the same color in adjacent triads is made equal to that between the dots of the same color in the delta-gun tube.
As shown in Fig.(b), the aperture mask has vertical slots corresponding to color phosphor stripes. One vertical line of slots is for one group of fine strips of red green and blue phosphors. Since all the three electron beams are on the same plane, the beam in the center (green) moves along the axis of the tube. However, because of inward tilt of the right and left guns the blue and red beams travel at an angle and meet the central beam at the aperture grille mask.
The slots in the mask are so designed that each beam strikes its own phosphor and is prevented from landing on other color phosphors. The P.I.L. tube is more efficient, i.e., has higher electron transparency and needs fewer convergence adjustments on account of the in-line gun structure.
It is manufactured with minor variations under different trade names in several countries and is the most used tube in present day color receivers.