Abstract: A projection cathode ray tube which comprises a glass bulb consisting of a funnel portion having a large opening at one side and a small opening at the opposite side, a panel portion which has the inner surface protruded in a convex form toward the interior of the cathode ray tube and which is sealingly attached to the large opening of the funnel portion, and a neck portion receiving therein an electron-gun, which is sealingly attached to the small opening of the funnel portion, wherein the inner surface protruded in a convex form of the panel portion is polished. A sealing surface in the panel portion does not protrude from a useful screen area in the inner surface of the panel portion. At least three reference points may be provided either on the funnel portion or on the panel portion, or on both of them.

Abstract: A process for producing aromatic polyether ketones and polythioether ketones, which comprises reacting aromatic ethers or thioethers represented by the general formula: ##STR1## where each of R.sup.1 to R.sup.12 is a hydrogen atom, a halogen atom, a hydrocarbon group or an alkoxy group, n is an integer of 0 to 5, and X is an oxygen atom or a sulfur atom, with phosgene in aprotic solvent having a dielectric constant of lower than 20 and a dipole moment of lower than 3.0 in the presence of anhydrous halides of metals of Group III in the periodic table as a catalyst.