Color picture tube having an expanded focus lens type inline electron gun with an improved stigmator

Abstract From the Canadian patent

An improved color picture tube has an inline electron gun for generating and directing three electron beams, a center beam and two side beams along coplanar, paths toward a screen of the tube. The gun includes a main focus lens for focusing the electron beams. The main focus lens is formed by two spaced electrodes each having three separate inline apertures therein. Each electrode also includes a peripheral rim. The peripheral rims of the two electrodes face each other. The apertured portion of each electrode is within a recess set back from the rim. The main focus lens electrode closest to the screen includes a slot on the side facing the screen. The slot extends in the direction of the …