JP3136522B2 - Cathode ray tube electron gun electrode - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a single electrode plate having a large thickness, in which the inner surfaces of the holes, including the periphery of the opening on the front and back of the electrode plate, are smooth, have high dimensional accuracy, and are uniform. The present invention relates to a cathode ray tube electron gun electrode having an electron beam passage hole for forming an electron lens, which is perforated in dimensions and shape, and particularly to an in-line type color cathode ray tube electron gun electrode.

[0002]

2. Description of the Related Art Since cathode ray tubes are generally mass-produced, cathode ray tube electron gun electrodes are usually manufactured by using a pressing method as widely as possible.

When the electrodes of the electron gun of the cathode ray tube are manufactured by press working, if the plate thickness is up to about 0.5 mm, a problem arises even if the electrode is manufactured by a conventional punching method, that is, by conventional punching. Absent. However, when the thickness of the electrode is as large as 0.8 mm or more, if the hole is drilled by conventional punching, a plan view is shown in FIG.
As shown in the cross-sectional view, at the time of drilling, the inner surface of the hole becomes a smooth shearing surface 6 at a certain depth from the surface of the electrode plate 4 on the side directly touched by the end of the punch, but is deeper than that. By the way, a large number of small irregularities are formed on the inner surface of the hole to form a fractured surface 5 which looks like a satin finish. As the thickness of the electrode is larger, the portion of the fracture surface 5 is proportionately larger.

The accuracy of the hole diameter and the accuracy of the hole diameter center with respect to the center axis of the electron beam orbit are lower in the fracture surface than in the shear surface. Further, the amount of the fracture surface varies depending on the press die used for manufacturing the electrode. In the portion where the inner surface of the electron beam passage hole has a broken surface as described above, the hole diameter accuracy and the hole diameter center accuracy with respect to the center axis of the electron beam trajectory are poor. In the case where the fracture surface of the beam passage hole is large, the focus characteristic of a cathode ray tube using the electron gun is adversely affected.

[0005]

As a countermeasure to the above-mentioned conventional problem, as shown in FIG. 4, two thin plate-like electrodes having electron beam passing holes formed at the same position by a conventional punching method are used. It has also been practiced to use them in such a manner that each fractured surface portion is placed inside so that the sheared surface portion is on both outer surface sides, but such a structure increases the man-hours for manufacturing the electrode and deteriorates the accuracy during assembly (electronic beam). However, there is a problem that the focus characteristic is not so much improved in spite of the increase in the cost of the electrode and the troublesome work.

Japanese Patent Application Laid-Open No. Sho 62-285336 discloses that, after forming an electron beam passage hole of a plate-like electrode having an electron beam passage hole in a plate-like member by pressing, the hole is formed. In the method of manufacturing a plate-like electrode for an electron gun for an electron tube, wherein the lower hole is formed by shaving, the lower hole is formed in a half-punched state by the press working, and the scrap is formed into the lower hole of the plate-like member. It is disclosed that the shavings are removed together with shavings generated by the shaving process in the shaving process. The purpose of this manufacturing method is that the scum generated during the preparation of the pre-hole or shaving remains in the mold and the scum is generated,
In order to prevent the outer periphery of the electrode and the vicinity of the electron beam passage hole from being damaged, and to prevent the cathode ray tube in which such an electrode is incorporated from having a withstand voltage defect or a focus defect, the hole is formed. It is not to improve the shape and dimensional accuracy of.
In addition, it is inevitable that a broken surface remains at one end of the hole during shaving.

According to the present invention, the inner surface of the hole, including the periphery of the opening on the front and back of the electrode plate, is smooth, high in dimensional accuracy, and uniform on a single electrode plate having a thickness of 0.8 mm or more. An object of the present invention is to provide a cathode ray tube electron gun electrode having an electron beam passage hole for forming an electron lens, which is formed in a desired size and shape.

[0008]

According to the present invention, there is provided a cathode ray tube having an electron beam passing hole having a hole depth of 0.8 mm or more formed by pressing for forming an electron lens. In the tube electron gun electrode, a single hole is formed on a single electrode plate having a thickness equal to the depth of the hole by first using a punch having a diameter smaller than a desired hole diameter to form a pilot hole, and then by shaving processing. Finishing into a hole of the desired size and shape having a smooth inner surface including most of the surface of the fractured surface generated during conventional punching, and chamfering or curved surfaces by taper symmetrically around the front and back surfaces of both ends of the hole Is chamfered to a depth substantially equal to the depth of the fractured surface portion remaining at one end of the hole even after the shaving process.
Alternatively, a tapered or curved surface may be formed before shaving.

[0009]

According to the above-described means, even when a thick electrode plate is used, the inner surface of the electron beam passage hole is smoothly finished by shaving processing and is perforated to a desired shape with high precision. In addition, some of the fractured surfaces remaining at one end of the hole after shaving are removed in the same way for each product by chamfering the front and back surfaces of both ends of the hole, improving the opening accuracy at the entrance and exit of the electron beam to the electrode plate. A cathode ray tube using such an electron gun electrode has good focus characteristics and high uniformity.

[0010]

FIG. 1 shows an embodiment of the present invention in an in-line type color cathode ray tube, and FIG.
FIG. 3B is a cross-sectional view taken along an orthogonal plane passing through the center of the central electron beam passage hole. FIG. 2 is an enlarged view of a cross section of the electron beam passage hole. In these figures, 1a, 1
b and 1c are electron beam passage holes arranged at equal intervals in a horizontal line, 2a, 2b and 2c and 3a, 3b and 3c are respectively around the front and back openings of the electron beam passage holes of the electrode plate. 2 shows a chamfered portion formed by a taper formed by press working. In this embodiment, 85% or more of the inner surface of the electron beam passage hole has a shear surface.

Electrodes of an electron gun used when the bulb diameter of the bulb is 29 mm. Each of the electron beam passage holes 1a, 1b,
The inner diameter of 1c was 4.0 mm, and the pitch of these holes was 5.5.
mm, the plate thickness of the electrode plate was 1.0 mm, and the depth of the chamfering process around the opening at both ends of the hole was 0.1 mm. A product having excellent focus characteristics and high uniformity was obtained.

[0012]

As described above, according to the present invention, the entire inner surface of the electron beam passage hole is smoothed and drilled with high shape and dimensional accuracy. Since both sides in the direction are pressed, the accuracy of opening on the front and back surfaces of the electrode plate can be improved, and the focus characteristics can be stabilized and a good cathode ray tube electron gun electrode can be obtained using one thick electrode plate.

[Brief description of the drawings]

FIG. 1A is a plan view of one embodiment of the present invention, and FIG. 1B is a cross-sectional view taken along an orthogonal plane passing through the center of a central electron beam passage hole of the embodiment.

FIG. 2 is an enlarged sectional view of an electron beam passage hole of the embodiment.

FIG. 3A is a plan view of a conventional cathode ray tube electron gun electrode,
(B) is a cross-sectional view taken along an orthogonal plane passing through the center of the central electron beam passage hole of the same conventional example.

FIG. 4 is a cross-sectional view of a conventional product in which two thin electrode plates are stacked to take measures to improve hole diameter accuracy.

[Explanation of symbols]

1a, 1b, 1c: electron beam passage holes, 2a, 2b,
2c, 3a, 3b, 3c: chamfered part, 4: electrode plate,
5: fracture surface, 6: shear surface.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-76230 (JP, A) JP-A-57-32536 (JP, A) JP-A-55-74036 (JP, A) JP-A-62 2425 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01J 29/50

Claims (3)

(57) [Claims] 1. A cathode-ray tube electron gun electrodes the electron beam apertures are formed by pressing the electrode plate for the electron lens forming, symmetrically peripheral portion of the front and back surfaces side of the electron beam passage holes of the electrode plate A cathode ray tube electron gun electrode characterized in that chamfering with a taper or chamfering with a curved surface is performed at a depth substantially equal to the depth of a fractured surface portion remaining at one end of the electron beam passage hole. 2. A cathode ray tube electron gun electrode in which an electron beam passage hole is formed in an electrode plate by press working to form an electron lens, wherein the electron beam passage hole has a depth of 0.8 mm.
A cathode ray tube electron gun electrode characterized in that the periphery of the electron beam passage hole on both the front and back surfaces of the electrode plate is chamfered by a taper or by a curved surface. 3. A cathode ray tube electron gun electrode in which an electron beam passage hole is formed in an electrode plate by press working to form an electron lens. A cathode ray tube electron gun electrode characterized in that chamfering is performed by a curved surface, and 85% or more of the inner surface of the electron beam passage hole is constituted by a shear surface.