JPH0740472B2 - Electron gun electrode assembly for cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to improvement of an electron gun electrode assembly used in a cathode ray tube.

<Prior Art> In a normal color cathode ray tube, a cathode structure that individually generates three electron beams and an electron lens that is electrically and structurally common and is substantially individual or common in each electron beam passage are provided. An in-line type electron gun having an integrated electrode to be formed is widely used.

FIGS. 2 and 3 show an example of an electron gun electrode assembly having such a structure. In an in-line type electron gun that generates three electron beams in the same plane, the main electron lens has a bi-potential potential.
FIG. 4 is a front view and a side view of the in-line type electron gun electrode assembly 1 for obtaining the focus system, and FIG. 4 is a line AA ′ in FIG.
FIG. The electron gun electrode assembly 1 is composed of three cathode assemblies 10A, 10B, 10C which are insulated from each other and arranged in a line at an equal distance S in the same plane, and are sequentially arranged in opposition to the electron beam advancing direction. GI electrode 11, G2 electrode 12, which are electrically common and have three electron beam transmission apertures arranged in-line.
Each of the electrodes is composed of a G3 electrode 13 and a G4 electrode 14, and each electrode has an electrode supporter 15 integrally formed with it, and an auxiliary supporter 16 attached as necessary to reinforce the support strength. By embedding it in 17, it is fixed while maintaining a predetermined electrode interval. Electron gun electrode assembly 1 cathode assembly 10A, 10
Three cathodes 10K are fixed to B and 10C corresponding to the electron beam paths kept at the distance S at a predetermined distance from the G1 electrode 11 and inserted into and fixed to the support cylinder of each cathode assembly. A heater is inserted in 10 K to heat the electron emitting material applied to the top of the cathode to 700 to 850 ° C.

In a color cathode ray tube equipped with such an electron gun electrode assembly 1,
By applying a voltage to the heater, the temperature of the cathode 10K rises, and the temperature of the G1 electrode 11 rises due to heat radiation and heat conduction from this, and the temperature at the stable time, which is sufficient time after ignition of the heater, is about 300 to 400. Rise to ℃. On the other hand, G2 electrode 12, G3 electrode 13
Since they are far from the heat source of the cathode and because they are structurally thermally shielded by the G1 electrode 11, the temperature is less than about 150 ° C.
Stable at a lower temperature than the electrode 11. Therefore, during the operation of the cathode ray tube, the temperature rise of the G1 electrode 11 is the largest except for the cathode structures 10A, 10B and 10C, and the thermal expansion of the electrodes is also the maximum. In the XY plane of FIG. 4, the G1 electrode 11 tries to thermally expand (F ₁ ) in the Y-axis direction, but the electrode support 15 has an insulator support rod 17
Since it is fixed in the Y-axis direction, thermal expansion (F ₂ ) occurs in the X-axis direction. Therefore, since the central opening 11B of the G1 electrode 11 is located at the center of the electrode, it does not move in the XY plane due to thermal expansion.
The 11Cs move away from each other on the X axis. For example, if the coefficient of thermal expansion of the G1 electrode 11 made of stainless steel is 18 × 10 ^-6 mm / ° C, the temperature of the G1 power source is 300 ° C and S = 6.6 mm, the movement amount due to the thermal expansion of the outer openings 11A and 11C is about 0.036 mm. Become.

After the color cathode ray tube is sufficiently thermally stable, adjust the three electron beams to concentrate on one point on the phosphor screen, then turn off the power supply and cool it sufficiently and then turn on the power to set the three electron beams on the phosphor screen. Looking at the movement of the electron beam, the outer electron beams on both sides change from the under-concentrated state to the over-concentrated state with the lapse of time from the above reason, and both outer electron beams coincide with the central electron beam after a lapse of 30 minutes or more. During this time, an undesired image with a color shift is displayed on the fluorescent screen. This is called thermal convergence drift.

<Problems to be Solved by the Invention> In order to prevent thermal convergence drift,
G1 electrodes 11 and G2 that heat up to the highest temperature during cathode ray tube operation
The electrode 12 may be formed of a low thermal expansion material. For example, 42% Ni
If you use 42 alloy which is Fe-Ni alloy consisting of
The coefficient of thermal expansion at 200-400 ℃ is about 7.2 × 10 ^-6 mm / ℃,
The thermal expansion of the G1 and G2 electrodes is less than half that of the conventional one, and the thermal convergence drift can be made to a practically negligible level.

However, in the electron gun electrode assembly 1, its electrode supporter 15
Of the insulating support rod 17 set to the same interval l ₀ of the cathode assembly 10, the G1 electrode 11 to G4 electrode 14, and the auxiliary support.
Up to 16, although they are all set to the same value l ₁ ,
During operation of the cathode ray tube, a difference in the coefficient of thermal expansion and temperature rise of the electrode forming material causes a difference in the buried width between the G1 and G2 electrodes 11 and 12 (particularly G1 electrode) and the other electrode. That is, thermal expansion was taken
The buried widths of the G1 and G2 electrodes 11 and 12 hardly change when the cathode ray tube operates and does not operate, but the other electrodes are asymmetric with respect to thermal expansion. A little larger than the buried width of 12,12. For this reason, concentrated stress is always applied in the vertical direction in the Y-axis direction in the vicinity of the embedded portions of the G1 and G2 electrodes 11 and 12 where the embedded width does not change due to the operation or non-operation of the cathode ray tube. Due to the thermal history of the cathode ray tube during operation and during non-operation, the insulator supporting rod 17 finally cracks near the embedded portion of the G1 electrode 11 or the G2 electrode 12, and the electron gun electrode assembly
It had the drawback of leading to the destruction of 11.

The present invention has been made in view of the above-mentioned drawbacks, and an electron gun electrode assembly capable of preventing thermal convergence drift in the electron gun electrode assembly for a cathode ray tube and preventing the electron gun electrode assembly from being destroyed. It is provided.

<Means for Solving the Problems> The present invention provides an electron gun electrode assembly for a color cathode ray tube, which is constructed by embedding a plurality of insulator support rods in a plurality of electrode supporters embedded in a plurality of insulator support rods. It is characterized in that the embedded width of the other electrode is made smaller than the embedded width of the electrode supporter of the electrode formed of the thermal expansion material and embedded in the insulator support rod.

With such a configuration, the electrode groups formed of materials having different thermal expansion coefficients are mixed and embedded in the insulator supporting rods set at the same intervals, so that the thermal history of the cathode ray tube during operation and non-operation can be improved. Even if received, it is possible to prevent the insulator supporting rod from being broken.

<Example> Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a side view of an electron gun electrode assembly 20 according to an embodiment of the present invention. As in the conventional case, the electron gun electrode assembly 2 has three cathode assemblies 20A, 20B, 20C which are insulated from each other and arranged in a line at equal distances S in the same plane, and the electron beam traveling in opposition thereto. Electrically common to each other sequentially,
Three electron beam transmission apertures are composed of G1 electrode 21, G2 electrode, G3 electrode and G4 electrode 24, which are arranged in-line, and each electrode is required to reinforce the support strength and the electrode support 25 integrally formed. two of the insulator support rod 17 which is parallel to set to be a distance l ₀ auxiliary Shijiko 26 attached according to
By embedding in, it is fixed while maintaining a predetermined electrode interval.

Note that the G1 electrode 21 and the G2 electrode 22 are formed of a low thermal expansion material, for example, 42 alloy, and other electrodes are formed of a stainless material in order to prevent thermal convergence / drift. In this case, the embedding width of the electrode supporter 25 with respect to the insulator supporting rod 17 of the G1, G2 electrodes 21, 22 is set to l ₁ as in the conventional case, and the other electrodes are set to the embedding width l ₂ smaller than l ₁ . . Therefore, the G1 electrode 21 and the G2 electrode 22 formed of the low thermal expansion material hardly undergo thermal expansion even by the heat from the cathode during the operation of the cathode ray tube, and the thermal expansion is less than the embedding width l _{1 of} the insulator supporting rod 17 Because of this, the embedded width l ₂ of the other electrode, which has a slightly larger thermal expansion width than the G1 electrode 21 and the G2 electrode 22, is smaller,
It is possible to equalize the stresses applied to the insulator support rod 7 from all the electrode supports by thermal expansion. For this reason, all of the electrode support 25 and the auxiliary support 26 are mounted on the insulator support rod 17.
A uniform stress is applied to the insulator support rod 17, and the insulator support rod 17 is prevented from being destroyed by the thermal stress of the insulator support rod 17 without giving a local strain stress to the insulator support rod 17.

In the above explanation, in order to make the stress of the electrode support embedded in the insulator support rod uniform, all electrodes are set to G1, G
The reason for not forming the same low thermal expansion material as the two electrodes is as follows.

That is, in general, the low thermal expansion material has physical properties close to those of the elastic material, making it difficult to press work or micro-perforate the G1 electrode and G2 electrode, and it becomes very difficult to draw the G3 and G4 electrodes. Furthermore, since the low thermal expansion material cannot be made non-magnetic, it will be affected by an external magnetic field, or magnetically shield the magnetic correction element placed outside the glass neck of the color cathode ray tube to render its action ineffective. This is because there are such effects.

In the above description, the case where both the G1 electrode and the G2 electrode are made of the low thermal expansion material is taken up, but the present invention is not necessarily limited to this, and only the G1 electrode closest to the cathode may be made the low thermal expansion material.

Needless to say, the present invention can be applied to a case where two or more insulator support rods are used, for example, two on each side of the electrode support, that is, a total of four.

<Effects of the Invention> As described above, according to the present invention, a plurality of electrode groups formed of materials having different coefficients of thermal expansion are mixed and embedded in an insulator supporting rod set at the same interval to form an electron gun. It is possible to prevent the destruction of the insulator supporting rod even when the cathode assembly is constructed and the thermal history of the cathode ray tube during the operation and non-operation is received.

[Brief description of drawings]

FIG. 1 is a side view of an in-line type electron gun electrode assembly according to an embodiment of the present invention, and FIGS. 2 and 3 are front and side views of a conventionally used in-line type electron gun electrode assembly, respectively. The drawing is a sectional view taken along the line AA 'in FIG. 10A, 10B, 10C, 20B …… Cathode structure, 11,21 …… G1 electrode, 12,22
...... G2 electrode, 13,23 …… G3 electrode, 14,24 …… G4 electrode, 15,2
5 ... Electrode support, 16, 26 ... Auxiliary support, 17 ... Insulator support rod, 11A, 11B, 11C ... G1 Electron beam transmission aperture.

Claims (1)

[Claims] 1. An electron gun electrode assembly for a cathode ray tube, comprising an electrode support provided on a plurality of electrodes embedded in two or more insulator support rods, and an electrode formed of a relatively low thermal expansion material. An electron gun electrode assembly for a cathode ray tube, characterized in that the embedded width of an electrode support of another electrode is smaller than the embedded width of the electrode support of (1) and the electrode support is embedded in an insulator support rod.