Electron gun of CRT and manufacturing method therefor

Abstract

An electron gun cathode structure includes a support member made of an insulating material, a first grid fixed to the support member, and a cathode disposed on the side of the support member opposite to the first grid. A thermal expansion .DELTA.L.sub.s /L.sub.s of the insulating material constituting the support member due to heat from the cathode is larger than a thermal expansion .DELTA.L.sub.G /L.sub.G of a material constituting the first grid due to heat from the cathode. A manufacturing method of an electron gun cathode structure includes preparing a member including a first face and a second face having a step therebetween, a height of the step being equal to a predetermined distance d.sub.12, placing a first grid on the first face, placing a spacer on the second face, placing an insulating support member on the first grid and the spacer, and grinding a top surface of the spacer opposite to its surface that is fixed to the support member so that an actual distance d.sub.12 becomes a desired value. Further, a distance d between the top surface of the spacer and a cathode is measured with a non-contact type distance measuring instrument, and a position of the cathode with respect to the first grid is so set that a difference d-d.sub.12 becomes a desired value.

Dependencies are inferred from the claim text.