[ohohyodafarted]

15Hp22 was made by CBS Hytron. CBS owned the patent on the photographic deposition method of putting the phosphor dots directly onto the inside face of the screen.

RCA used a silk screening method to deposit phosphor dots onto a flat glass plate which was mounted inside the crt bulb.

IIRC RCA did some patent exchanges with CBS in order to be able to deposit phosphor dots directly onto the inside face of the 21AXP22. One of the rare instances that RCA had to grovel to another competitor to obtain the rights to a patent that RCA could not get around. Sarnoff was a real SOB and vowed that if RCA did not invent something they would not use it. But in this case Sarnoff had to eat crow.