JPS62145631A - Electron gun body structure - Google Patents

Abstract

PURPOSE:To obtain an electron gun body structure having favorable beam focus characteristic and static convergence characteristic in active temperature without needing a jig newly, by making the second grid electrode as a bimetal structure. CONSTITUTION:The first grid electrode 2 or the second grid electrode 3 is made as a structure that the metal plates of different coefficients of thermal expansion such as a bimetal are stuck to each other. The electrode around both side beam transit holes of the first grid electrode 2 and the second grid electrode 3 which are fixed to an insulating support as not shown with up and down four points is able to be transformed in the travelling direction of electron beams or in the contrary direction thereof under active temperature. This transformation is merely owing to the nature of the bimetal, so that no jig is needed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to an in-line electron gun assembly used in a color picture tube or the like, and particularly to the structure of a first grid electrode and a second grid electrode.

[Background of the invention]

FIG. 1 shows a horizontal sectional view of an embodiment of the present invention.

This figure is the same as the conventional in-line electron gun assembly for a color picture tube except for the structure of the second grid electrode, so problems with the conventional electron gun will be explained using this figure.

In the figure, 1 is three cathodes, 2 is a first grid electrode, 3 is a second grid electrode, 4 is a third grid electrode, 55 is a fourth grid electrode,
6 each represents a shield cup. The three electron beams 7a, 7b, 7c emitted from the cathode l are the first
Grid electrode 2, second grid electrode 3. Passing holes 2a to 4a, 2b to 4b, and 2c to 4 respectively provided in the fourth grid electrode 4
After passing through the side beams 7a and 7c separately,
is an asymmetric main lens 6a formed by electron beam passing holes 4a' and 5a provided corresponding to the third grid electrode 4 and fourth grid electrode 5, respectively, or an asymmetric main lens 6a formed by similarly passing holes 4c' and 50. By passing through each lens 6c, the paths of the beams are bent in the direction of the center beam 7b, and the beams are concentrated at one point on a phosphor screen (not shown). The operation of the electron gun has been explained using an example of an electron gun in which the first grid electrode 2 and the second grid electrode 3 of the electron gun structure are integrated, but both electrodes have an electrode part with a center beam optimization hole and a side beam Some are separated into two electrode parts that also have optimization holes.

In any case, in these conventional electron guns, a prefocus lens is formed between the side beam passage holes 3a, 3C of the second grid electrode 3 and the corresponding passage holes 4, □, 4c of the third grid electrode 4. form an asymmetrical upper bound, and as a result, the side beams 7a and 7c are connected to the main lenses 6a and 6.
Before each beam enters C, it is deflected toward the center beam 7b, causing misconvergence due to overconcentration or blurring of concentration due to spherical aberration of the main lens.

In order to solve this problem, in an electron gun in which the first grid electrode 2 and the second grid electrode 3 are of a separate type, the part of the electrode having electron beam passing holes on both sides, which is far from the central axis of the electron gun, is the third grid electrode 4. There are examples in which the first grid electrode 2 or the second grid electrode 3 is installed away from the flat part of the second grid electrode 3 (Japanese Unexamined Patent Publication No. 70662/1982), and in an electron gun structure that is completely integrated, the flat part of the second grid electrode 3 and the The distance to the facing third grid electrode is t'lt
There is an example (Japanese Patent Application Laid-open No. 87739/1989) in which the second grid electrode is modified so that it becomes larger, such as moving away from the center of the child gun. By these operations, the side beams 7a and 7C become 4a and 4C.
The beam propagates along the axis of the sensor beam and prevents it from being deflected toward the sensor beam, thereby improving the static convergence characteristics and beam spot characteristics.

However, the improvement according to the above-mentioned known example requires a jig to deform the first grid (six-pole electrode 2) or the second grid electrode 3, and the effect of deforming the electrode is reduced due to thermal expansion of each electrode during operation. There are problems such as the possibility of

[Purpose of the invention]

The object of the present invention is to provide a first grid electrode 2 or a second grid electrode 3.
is deformed at the operating temperature without using a jig or the like,
The object of the present invention is to provide an electron gun structure with good beam focus characteristics or static convergence characteristics on a fluorescent screen.

[Summary of the invention]

To achieve the above object, the present invention provides a first grid electrode 2
Alternatively, the second grid electrode pi3 may have a structure in which metal plates having different coefficients of thermal expansion, such as bimetals, are bonded together. As a result, the first
The grid electrode pA2 or the electrodes around both side beam passage holes of the second grid electrode 3 can be deformed in the direction of electron beam travel or the opposite direction at the operating temperature. This deformation is simply due to the nature of the bimetal and does not require any jig.

[Embodiments of the invention]

FIG. 1 shows, as an embodiment of the present invention, an electron gun having an in-line integrated structure in which the second grid electrode 3 is made of metals 31 and 32 having different coefficients of thermal expansion. The difference from the conventional example is that the second grid electrode has a bimetal structure.

FIG. 2 shows an enlarged view of the embodiment from the cathode 1 to the third grid electrode 4 in the embodiment of FIG. 1 at operating temperatures, and the operation of this embodiment will be explained.

During operation, normally the cathode I is at about 740°C, the first grid electrode 2 is at about 210°C, and the second grid electrode 3 is at about 125°C.
It is heated to a certain degree. Therefore, by constructing the second grid @ pole 3 using a metal with a relatively high coefficient of thermal expansion for 31 and a metal with a relatively low coefficient of thermal expansion for 32, the metal parts between 3a and 3b and between 3b and 30 The second grid electrode 3, whose upper and lower sides are fixed with insulated indicators, can be easily deformed as shown in FIG. Further, the amount of deformation can be set by changing the ratio of the metal thicknesses of 31 and 32.

In this embodiment, since it is possible to deform the electrode as shown in FIG. 2 during operation, it is possible to create a new shape using a jig for deforming the electrode as described above using the known example. It is not necessary and can be easily obtained, and thereby the beam spot characteristics and static convergence characteristics on the phosphor screen can be improved.

Next, as a second example, in an electron gun in which the first grid electrode 2 and the second grid electrode 3 are not integrated, the metal pieces having the side beam passage holes 2a and 2c of the first grid electrode 2 are each formed into a bimetal structure. An example of this is shown in Figure 3. In this example, a metal with a relatively high expansion coefficient is used for 21, a metal with a relatively low expansion coefficient is used for 22, and the metal piece 1 having the center beam passage hole 2b remains the same as before. By partially using bimetal in this way, the same effect as the previous example can be obtained.

In the above embodiments, the first grid electrode 2 or the second grid electrode 3
Although an electron gun in which either one of the two has a bimetal structure has been described, it is of course also effective to make both of them a bimetal structure.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to obtain an electron gun assembly with good beam focus characteristics, static convergence characteristics, etc. at the operating temperature without requiring any new jig.

[Brief explanation of drawings]

FIG. 1 is a horizontal cross-sectional view of an in-line electron gun assembly which is an embodiment of the present invention, and FIG. 2 is a diagram showing the operation of the three-pole section and prefocus section of the in-line integrated electron gun according to the present invention. FIG. 3 is an enlarged sectional view of a triode section and a prefocus section of an in-line electron gun having partially separated grid electrodes according to the present invention. DESCRIPTION OF SYMBOLS 1... Cathode, 2... First grid electrode, 3... Second grid electrode, 4... Third grid electrode, 5... Fourth grid electrode 68-6c... Main electron lens , 7a-7c...
electron beam. Early 1st 2nd mouth 4th

Claims (1)

[Claims] 1. In an in-line electron gun, at least the whole or part of the first grid electrode or the second grid electrode has a structure in which at least two metal sheets having different coefficients of thermal expansion are bonded together in the direction from the cathode to the third grid electrode. An electron gun structure characterized by: