[etype2]

Originally Posted by old_tv_nut

The unbroken vertical stripes mean that the shadow mask is not self supporting and must be made of strips under tension (Trinitron). By using broken stripes, the shadow mask is self supporting, just like a delta-gun mask. A disadvantage of continuous stripe screens is that less area is avaialble for black matrix, so the screen is more reflective of room light. However, a tension mask can take much more beam current before going out of shape, so the disadvantage can be reduced by using darker faceplate glass and more beam current to make up for the loss in brightness.

The heat build up problem was solved by running two fine tungsten wires across the aperture grille horizontally to keep the vertical wires of the grille rigid. This was done on the very first Trinitron. Sometimes a shadow was present from the tungsten wires, but in practice, not noticeable. The Trinitron stripes were wider then the slot mask tubes together with a greater percentage of electron energy reaching the screen provided a highly luminous image. The lower beam current on the first Trinitron required only 65watts (Max.) of power.

The really big advantage in in-line gun tubes is the simplification of convergence and loosening of tolerances needed to maintain purity. The final result was tubes needing no complex dynamic convergence circuits, with all CRT adjustments obtained by yoke and permanent magnet adjustment. This sequence of development was a major factor in reducing color TV prices in real terms. While general inflation went up by a factor of 7 to 10 times, color TV set prices stayed constant or actually declined. There was a long period when the common color TV set was a 19 inch table model selling for about $300.

Indeed, an advantage and the Trinitron required only two convergence controls as opposed to 16 in a delta CRT. Focusing three inline electron beams from one gun through the center of one “electronic lens” instead of three, provided better focus and depth of field then a delta gun tube. An analogy: in photography, the center of the lens is the sharpest. Additionally, Trinitron CRT’s achieved wide deflection angles which allowed the single gun closer to the aperture grill for better focus and slimmer cabinets.