JPH02112136A - Inline type electron gun body structure - Google Patents

Abstract

PURPOSE:To enable the fitting of raster sizes on the fluorescent surfaces of center and side beams without deflection error by making each beam passing hole of an accelerating focusing electrode in a cylindrical form and varying the respective length and sectional form between the center and both sides thereof. CONSTITUTION:The relation of each beam passing hole of a first accelerating focusing electrode 4 and second accelerating focusing electrode 5 is set C1<C2, B1<B2, A1<A2. Thus, the electric potential distribution is made as shown by the dotted line in the drawing, and a high electric potential is applied to the center beam from near a cathode 1b of its emitting point. Therefore, the center beam is more strongly drawn than the side beams, and the horizontal raster size of the center beam is increased on the fluorescent surface. On a plane surface formed by the vertical axis and pipe axis containing each electron gun, the vertical raster size on the fluorescent surface can be changed by the center and side beams by mutually changing each beam passing hole length, A1 and A2, B1 and B2, and C1 and C2.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to an in-line electron gun assembly suitable for use in a color picture tube.

(Prior Art) In general, in a color picture tube equipped with an in-line type electron gun structure, when deflected by an external magnetic deflection yoke, the raster dimensions of the center beam and the side beams on both sides change on the screen (phosphor screen) due to the coma distortion. ) is different in each part, which may cause misconvergence.

Therefore, as a countermeasure against this problem, a magnetic material for controlling the deflection sensitivity (rusk size) is usually provided on the plane of the electron gun assembly of the color picture tube.

That is, a conventional color picture tube equipped with an in-line electron gun structure is constructed as shown in FIG. A glass vacuum envelope is formed. And face plate 1
A phosphor screen 14 is formed on the inner surface of the tube 1, and this phosphor screen 14 is a linear phosphor screen in which band-shaped phosphors are arranged substantially parallel to the short axis of the tube axis (direction perpendicular to the plane of the paper). A shadow mask 15 is detachably attached to face the phosphor screen 14 by conventional means. On the other hand, neck 1
An in-line electron gun assembly 16 is housed within the vacuum envelope 3, and a deflection yoke 7 is attached near the boundary between the funnel 2 and the neck 3 of the vacuum envelope.

By the way, the conventional in-line type electron gun assembly 16 is constructed as shown in FIGS. 4 and 5, and includes three cathodes 1a,
,b,],c are arranged at equal intervals on the same plane. each cathode], a, 1 b, 1 ci, respectively: a control electrode 2, a shielding electrode 3, a first accelerating and focusing electrode 4, a second accelerating and focusing electrode 5, and a non-magnetic shield each having a beam passage hole. Cups 6 are sequentially arranged at predetermined intervals, and are supported by glass supports (not shown).

As is clear from FIG. 3, such an in-line electron gun assembly 16 generates three electron beams 18 during operation, and these electron beams 18 pass through the shadow mask 15 along a concentrated path on the same plane. The light collides with the fluorescent screen 14.

In this case, vertical and horizontal magnetic fluxes are applied to the three electron beams 18 by the deflection yoke 17, and the beams are deflected horizontally and vertically to scan, thereby forming a rectangular raster on the phosphor screen 14.

As shown by the line pp in Fig. 3, the deflection starting plane is approximately l-/3 (=1) of the deflection yaw 17, or because of one leakage magnetic flux, the deflection area of the color picture tube or the deflection yoke]
-7 to the area of [electron gun structure]6 in the axial direction. Note that for simplicity, the actual curve of the deflected beam path in the deflection region is not shown in FIG.

By the way, as is clear from FIGS. 4 and 5, two annular magnetic bodies 7a and 7c are arranged at the bottom of the shielding cup 6 along the beam passage holes on both sides. The leakage magnetic flux 19 from the deflection yoke 17 extends to the rear of the shielding cup 6, so that the electron beam is slightly deflected just before the electron beam 18 passes through the magnetic bodies 7a and 7c. Conventionally, using this leakage magnetic flux] 9, the magnetic body 7a is
.

7c is placed at the bottom of the shielding cup 6 to shield the leakage magnetic flux [9] from being deflected to the side beams, and by strengthening the deflection of the center beam, the raster sizes of the center beam and the side beams are matched.

(Problems to be Solved by the Invention) However, the magnetic body 7as7c has a property called magnetization (magnetization). Due to this characteristic, there is a phenomenon in which the center beam deviates to the left of the side beams near the center of the phosphor screen 14 and does not deviate near the periphery of the phosphor screen 14.

To explain this phenomenon, when horizontally deflecting magnetic flux is horizontally deflected from left to right on the phosphor screen 14, the magnetic flux densities of the magnetic bodies 7a and 7c draw a POQ curve as shown in FIG. In this case, POQ is the horizontal deflection direction, and QRP is the retrace period of the horizontal deflection, which is a portion that cannot be seen on the phosphor screen 1-4.

Therefore, residual magnetization of magnitude A remains at the center of the phosphor screen. This residual magnetization generates a magnetic field as shown in FIG. 7(a), which acts more strongly on the side beams than on the center beams.

As a result, the side beam is deflected to the right of the center beam at the center of the phosphor screen, causing a leftward shift phenomenon of the center beam. However, as can be seen from the two points of the hysteresis curve and point Q, the area around the phosphor screen is magnetized symmetrically, as shown in FIG. 7(b), and no leftward deviation of the center beam occurs. Therefore, if we adjust the left deviation of the center beam on the fluorescent screen using a magnet, we get
There is a problem that the center beam may shift to the right around the phosphor screen 14.

In this way, one leakage magnetic flux of the deflection yoke 17 is used,
The magnetic material 7a%7C, which is used to match the raster sizes of the center beam and side beams on the phosphor screens 1-4 by controlling each of them, inevitably has a residual amount, as can be seen from the hysteresis curve in Figure 6. Magnetization remains.

Therefore, a deviation in deflection (misalignment) occurs between the center beam and the side beams at the center of the phosphor screen.

This invention was made in view of the above circumstances, and the raster size on the fluorescent screen of the center beam and side beam, which is the purpose of the magnetic material, can be improved without causing deflection deviation (positional deviation) and without using a magnetic material. [Structure of the Invention] (Means for Solving the Problems) This invention provides an in-line electron gun structure in which each beam passage hole of an acceleration and focusing electrode is formed into a cylindrical shape. , is an in-line electron gun assembly configured such that lengths or cross-sectional shapes are different between the center and both sides.

(Function) According to the present invention, it is possible to match the raster sizes of the center beam and side beams on the fluorescent screen, which is the purpose of the magnetic material, without causing deflection deviation (positional deviation) and without using a magnetic material. I can do it.

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

The potential distribution of a conventional general electron gun structure is as shown in FIG. Potential penetrates toward the control electrode. As a result, only the center beam is pulled at a higher potential than the side beams, and the raster size of the center beam becomes larger on the phosphor screen.

Therefore, the in-line electron gun assembly of the present invention is constructed as shown in FIG. 1, and the same parts as in the conventional example (FIG. 4) are designated by the same reference numerals (=I).

As shown, three cathodes on the same line]-a11b, l
They are arranged at predetermined intervals. These three cathodes], a
, ], b, lc, control γ cathode 2, shielding electrode 3,
A first acceleration and focusing electrode 4, a second acceleration and focusing electrode 5, and a shielding cup 6 are sequentially arranged at predetermined intervals. Each electrode 2.3.4.5.6 then has three cathodes 1as1. bslC
Each has a corresponding beam passage hole.

That is, the control electrode 2 has beam passage holes 2], 22, 23. The shielding electrode 3 has beam passing holes 31, 32, 33.
have.

Further, the first accelerating and focusing electrode 4 has beam passage holes 41, 42, 43 on the electron beam input side, and beam passage holes 44, 45, 46 on the electron beam output side.

In this case, the beam passage holes 4] to 46 are all cylindrical, and the beam passage holes 42 and 45 in the center are short in length;
The beam passage holes 4], 43, 44, and 46 on both sides are set long.

In other words, if the length of the beam passing hole 42 in the center is 01, and the length of the beam passing holes 41.43 on both sides is shifted from C2, then C
, <C2. If the length of the other central beam passage hole 45 is B, and the length of the beam passage holes 44.46 on both sides is B2, then B is set to <82.

Furthermore, the second accelerating and focusing electrode 5 has beam passage holes 51, 52, 53 on the input side of the electron beam. in this case,
The beam passage holes 51, 52, 53 are all cylindrical,
The length of the beam passing hole 52 in the center is long, and the beam passing holes 51 and 53 on both sides are set short.

In other words, if the length of the central beam passing hole 52 is A, and the length of the beam passing holes 51.5B on both sides is A2, then A,
>A2.

Further, the shielding cup 6 has beam passing holes 6], 62, 63, and in this invention, no magnetic material is provided as in the prior art.

Now, in the above case, the relationship between the beam passing holes of the first acceleration and focusing electrode 4 and the second acceleration and focusing electrode 5 is set as described above, so the potential distribution is as shown by the dotted line, and the center beam is A high potential is applied from the vicinity of the cathode 1b at the emission point of the center beam. Therefore, the center beam is pulled more strongly than the side beams, and the horizontal raster size of the center beam becomes larger on the fluorescent screen 14.

On the other hand, a plane surface that creates vertical axes and tube axes containing each electron gun,
By changing the mutual lengths of 1711A and A2 in FIG. 1, B1 and 82, and CI and 02, the vertical raster size on the phosphor screen 14 can be changed between the center beam and the side beam.

- As an example, if the lengths of B1 and 82 of the first accelerating and focusing electrode 4 are the plane between the horizontal axis and the tube axis BI 82 = 2 mm and the plane between the vertical axis and the tube axis BI 82 = 1 mm, then in a 14' color picture tube, the fluorescence The horizontal raster size on surface 14 changes by about 1 mm, and the vertical raster size changes by about 0.5 mm.

(Modified Example) FIG. 2 shows a modified example of the present invention, in which the same effects as in the first embodiment can be obtained. That is, in the case of this Figure 2,
The upper half of the first accelerating and focusing electrode 4 is shown, and cuts 45a145b are provided on both sides of the central beam passing hole 45 (beam passing holes 44 and 46 side). In other words, X
The length in the tube axis direction is set to be different between the tube axis direction and the Y direction.

According to this modification, the potential distribution mainly changes in the lateral direction,
It is possible to mainly increase the raster size of the center beam in the lateral direction.

Furthermore, in the above embodiments and modifications, the acceleration focusing electrode 4.5
The lengths of the beam passing holes in the center and both sides were different, but even if the lengths were the same and the cross-sectional shapes were different between the center and both sides, the same effect as in the above example could be obtained. can get.

[Effects of the Invention] According to the present invention, deflection deviation (position deviation) between the center beam and the Zide beam at the center of the phosphor screen is caused by the residual magnetization of the magnetic material that utilizes the leakage magnetic flux of the deflection yoke.
It's fleeting. Furthermore, even without using a magnetic material, it is possible to match the rask size of the center beam and the zyte beam around the phosphor screen, which is a function of the magnetic material.

[Brief explanation of drawings]

FIG. 1 is an analytical view showing an in-line electron gun assembly according to an embodiment of the present invention, FIG. 2 is a perspective view showing a modification of the invention, and FIG. 3 is a diagram showing a conventional in-line electron gun assembly. 4 is a sectional view showing a conventional in-line electron gun structure; FIG. 5 is a plan view showing a shielding cup of the conventional in-line electron gun structure; FIG. The figure is a characteristic curve diagram showing the hysteresis curve of the magnetic material, Figures 7(a) and (b) are plan views showing the pattern of the magnetic field in the shielding cup of a conventional in-line electron gun assembly, and Figure 8
The figure is a cross-sectional view showing the pattern of the magnetic field at the first accelerating and focusing electrode and the second accelerating and focusing electrode of a conventional in-line electron gun 11η. 1 a % 1 b s 1 c... cathode, 2... control electrode, 3... shielding electrode, 4... first acceleration focusing electrode,
5... Second acceleration focusing electrode, 6... Shielding cup, 41
．． 42.43.44.45.46.51.52.53・
・Bim passage hole. applicant's agent

Claims (1)

[Claims] In an in-line electron gun structure, in which three cathodes, a control electrode, a shielding electrode, and at least one acceleration and focusing electrode each having a beam passage hole corresponding to each cathode are sequentially arranged at a predetermined interval, An in-line electron gun assembly characterized in that each beam passing hole of the acceleration and focusing electrode is cylindrical, and the length or cross-sectional shape is different between the center and both sides.