JPH036614B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides a metal cylinder body having an annular flange portion, an annular metal plate, and a metal mesh plate having a peripheral edge sandwiched between the flange portion and the metal plate. This relates to a mesh electrode for an image pickup tube comprising: a thickness of the cylindrical portion of the metal cylinder;
By making the thickness of the flange portion continuously formed on the cylindrical portion approximately half or less, it is possible to increase the diameter of the electrode and therefore the lens diameter, and to improve the resolution by reducing lens aberration. That's what I got.

A photoconductive image pickup tube used in a television camera or the like is usually constructed as shown in FIG. 1, with a mesh electrode 3 disposed between a final focusing electrode 1 and a target electrode 2. The mesh electrode 3 consists of a metal cylinder 3b having an annular flange 3a, an annular metal plate 3c, and a circular thin metal mesh plate 3d. The periphery of is sandwiched. Then, on the outer peripheral surface of the final focusing electrode 1,
A metal sleeve 5 is attached coaxially through an annular insulator 4 made of alumina porcelain, and the metal cylinder 3b of the mesh electrode 3 is fixed to the tip of the metal sleeve 5. The target electrode 2 consists of a transparent conductive film 7 attached to the inner surface of a glass face plate 6 and a photoconductive film 8 attached to the inner surface of this film 7. 9 is a cathode, 10 is a control electrode, 11 is an acceleration electrode, 12 is a first focusing electrode, 13 is a second focusing electrode, and 14 and 15 are metal bands as fasteners for the annular insulator 4.

The mesh electrode 3 captures secondary electrons and creates an electron lens between it and the final focusing electrode 1. Therefore, even the slightest eccentricity is not allowed between the mesh electrode 3 and the final focusing electrode 1. Moreover, it is made of copper or nickel.
A fine metal mesh plate 3d with a light transmittance of 500 to 1500 lines/inch and a light transmittance of about 40 to 55% has a flange part 3a sandwiching its periphery and an annular metal plate 3 with a plate thickness of about 0.1 mm.
After being welded to c, it is heated to several hundred degrees in a vacuum or hydrogen atmosphere for recrystallization.
In particular, high mechanical strength is required for the flange portion 3a.

For this reason, the plate thickness of the flange portion 3a is at least
The thickness of the cylindrical part of the metal cylinder 3b is approximately twice that of the final focusing electrode 1 (approximately 0.2 mm). This has been one of the factors that prevents the diameter of the electron lens generated between the two.

The present invention has been made with the above-mentioned points in mind, and the mesh electrode for an image pickup tube of the present invention is constructed, for example, as shown in FIGS. 2 and 3. That is, the flange portion 3 of the metal cylinder 3e that sandwiches the metal mesh plate 3d with the annular metal plate 3c.
f has a plate thickness T that is comparable to or greater than that of the conventional plate, but the wall thickness t of the cylindrical portion 3g continuously formed on the flange portion 3f is approximately half or less of the plate thickness T. . In other words, if the plate thickness T is approximately 0.4 mm, the wall thickness t can be approximately 0.2 mm, and the plate thickness T
If the thickness is approximately 0.5 mm, the wall thickness t should be approximately 0.1 mm to 0.25 mm.
It can be made into mm. The plate thickness T is selected to be about 0.4 mm or more, preferably about 0.5 mm or more.

The mesh electrode according to the present invention configured as described above can increase the diameter of the cylindrical portion 3g of the metal cylinder 3e without impairing the support strength of the metal mesh plate 3d, and the final focusing distance between the metal cylinder 3e and the final focusing By increasing the diameter of the electron lens generated between the electron lens and the electrode 1, the influence of lens aberration can be reduced and resolution can be increased. Further, since the coaxiality between the flange portion 3f and the cylindrical portion 3g integrated therewith can be maintained to a high degree, eccentricity does not occur between the final focusing electrode 1 and the cylindrical portion 3g.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the electrode configuration of a conventional image pickup tube, FIG. 2 is a sectional view of a main part of an embodiment of the mesh electrode for an image pickup tube of the present invention, and FIG. 3 is a cutaway perspective view of the same main part. be. 3c...metal plate, 3d...metal mesh plate, 3
e...metal cylinder body, 3f...flange part, 3g...
Cylindrical part.

Claims (1)

[Claims] 1 A metal cylinder body having an annular flange portion, a metal mesh plate having an annular metal plate and a peripheral edge sandwiched between the flange portion and the metal plate, the cylindrical shape of the metal cylinder body A mesh electrode for an image pickup tube, wherein the mesh electrode has a wall thickness that is approximately half or less of the thickness of the flange portion continuously formed thereon.