JP2595954B2 - Cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention enables so-called dynamic misconvergence correction of a cathode ray tube, that is, a convergence-free deflection yoke (CFD), a pin-free deflection yoke (PFD) and the like. The present invention relates to a color cathode ray tube having a deflection yoke, and particularly to correction of lateral misconvergence of a center beam.

[Summary of the Invention]

The present invention relates to a color cathode ray tube having a deflection yoke provided to enable dynamic convergence, wherein a flat plate is formed in parallel with 2 on an inner surface of an open end of an inner electrode of an electrostatic convergence means provided integrally with an electron gun. By arranging the magnetic small pieces, only the lateral misconvergence of the center beam can be independently corrected without affecting the longitudinal misconvergence of the center beam.

[Conventional technology]

2. Description of the Related Art There has been proposed a cathode ray tube in which a plurality of electron beams arranged in an in-line arrangement are scanned with respect to a stripe-type color phosphor screen so that dynamic misconvergence can be corrected by appropriately selecting a magnetic field distribution of a deflection yoke. The deflection yoke designed in this way is called a convergence-free deflection yoke (CFD). Also, since the pin-free deflection yoke (PFD) is generally designed to include the CFD, it has the same dynamic misconvergence correction function. On the other hand, as an electron gun used for such a color cathode ray tube, a double beam single electron gun having an electrostatic convergence means as shown in FIG. 10 is known. This electron gun has a first grid G ₁ , a second grid G ₃ common to three cathodes Kr, Kg, Kb corresponding to red, green and blue.
Grid G _2, the third grid G _3, fourth grid G ₄ and the fifth
Is the grid G ₅ is arranged, composed of four electrode plates downstream of the fifth grid _{G 5 (7a) (7b)} (7c) and electrostatic convergence diene scan means comprising (7d) (6) is arranged. Each electron beam crosses approximately at the center of the main electron lens formed by the third, fourth and fifth grids G ₃ , G ₄ and G ₅ , passes through the electrostatic convergence means (6), and converges on the phosphor screen. Is done.

In a convergence-free deflection yoke, the magnetic field of a horizontal deflection magnetic field coil (saddle coil) is used as a pincushion magnetic field and the magnetic field of a vertical deflection magnetic field coil (toroidal type coil) is used as a barrel magnetic field to correct dynamic misconvergence. ing. However, the dynamic misconvergence cannot be completely corrected, and as shown in FIG. 9, the center beam (1B) (1R) with respect to the side beams (1B) and (1R) at the screen X end and at the corner (not shown). 1G) horizontal misconvergence (hereinafter referred to as HCR) and the screen Y
Center beam (1G) at end, corner (not shown)
Vertical misconvergence (hereinafter referred to as VCR) occurs. These HCR and VCR values are adjusted to be within the standard. The values of HCR and VCR are negative if the center beam (1G) is misconvergence toward the center of the screen at the X and Y edges of the screen with respect to the side beams (1R) and (1B), and vice versa. Value. Normally, as shown in FIG. 9, VCR is on the minus side, and HCR is on the plus side.

Therefore, when designing and developing such a convergence-free deflection yoke, the magnetic field distribution is adjusted before and after by the shape of the horizontal deflection coil, that is, the side beam (1) is adjusted.
R) (1B) To obtain the dynamic convergence, use a pincushion magnetic field as a whole, but to adjust the HCR, partially create a barrel magnetic field in front (cathode side) of high misconvergence sensitivity to the beam. Is kept small. Next, an adjustment is made to minimize the misconvergence of other types (other than HCR). At the stage of performing this adjustment, the horizontal deflection magnetic field is readjusted, and the HCR may increase to a level that cannot be ignored. Figure 10 and 11 of the electron gun as shown in FIG convergence diene scan means (6) the fifth grid G ₅ positions U-shaped pair consisting of permalloy of side pole piece with respect to VCR (21) [( 21a)
(21b)] is corrected by welding. A part of the magnetic field (23) passes through the pole pieces (21a) and (21b) by the VCR correction pole pieces (21a) and (21b), and the magnetic field applied to the side beams (1R) and (1B) is weakened. At the same time, the magnetic field for the center beam (1G) is strengthened, and the swing delay of the center beam (1G) is corrected, so that the VCR is corrected.

On the other hand, in the prior art, in order to correct the above HCR,
A pair of U-shaped pole pieces (24) [(24a), (24b)] made of permiro are attached to the electron gun. However, the position of the HCR correction pole pieces (24a) and (24b) is generally the same as that of the VCR correction pole piece (21) because the horizontal deflection magnetic field coil is a saddle type. The density is small and it is difficult to correct HCR. For this purpose, as shown in FIGS. 10 and 12, an HCR correction pole piece (24) is mounted near the tip of the convergence means (6) having a relatively large magnetic flux density.

[Problems to be solved by the invention]

However, since the conventional HCR correction pole piece (24) has a U-shape, the vertical deflection magnetic field is also changed simultaneously by the part (plate-shaped part) parallel to the direction of the vertical deflection magnetic field. The pole piece (21) had to be redesigned.

In many cases, the operation of attaching the HCR correction pole piece (24) to the convergence means (6) is performed after assembling the electron gun, that is, after the beading step of holding each electrode with bead glass. The workability was poor such as deformation, and the magnetic properties of the HCR correction pole piece (24) were liable to change due to heat during welding, and the misconvergence (HCR) was unstable.

The present invention has been made in view of the above-described circumstances, and provides a cathode ray tube capable of performing HCR correction so that the effect on VCR is small and the HCR is stabilized.

[Means for solving the problem]

The present invention provides a pair of first electrode plates, ie, outer electrode plates (7c) and (7d), and a pair of second electrodes disposed in parallel between the first electrode plates (7c) and (7d). A cathode ray tube having an electron gun (14) provided at a subsequent stage with an electrostatic convergence means (6) composed of plates or inner electrode plates (7a) and (7b) and a deflection yoke (15); The inner electrode plates (7a) and (7b) constituting the means (6) are provided with flat magnetic pieces (32) parallel to the inner electrode plates (7a) and (7b) on the inner surfaces of the open ends.

To correct the lateral misconvergence of the center beam to the negative side, a pair of magnetic pieces are opposed to each other at positions corresponding to the centers of both inner electrode plates (7a) and (7b) as shown in FIG. (32) is provided. When correcting the lateral misconvergence of the center beam to the plus side, the two side electrode plates (7a) and (7b) face each other on both sides of the open end inner surfaces as shown in FIG. A pair of magnetic pieces (32) are provided.

[Operation] As shown in FIG. 2, electrostatic convergence means (6)
When the magnetic pieces (32a) and (32b) are provided at the center of the inner surfaces of the open ends of the inner electrode plates (7a) and (7b), the magnetic field distribution of the horizontal deflection magnetic field (pincushion magnetic field) (32) is As shown in the figure, the magnetic field (3
1) is weakened, so the HCR is corrected to a negative value.

As shown in FIG. 4, two pairs of magnetic pieces (32a) and (32b) were provided on both sides of the inner surfaces of the open ends of the inner electrode plates (7a) and (7b) of the electrostatic convergence means (6). At this time, the magnetic field distribution of the horizontal deflection magnetic field (31) is as shown in FIG. 5, and conversely, the magnetic field (31) for the center beam (1G) is strengthened and the HCR is corrected to the plus side.

Moreover, since the HCR correction magnetic piece (32) is arranged so that its plate surface is perpendicular to the vertical deflection magnetic field (barrel magnetic field), the vertical deflection magnetic field vertically aligns the plate surface of the magnetic piece 32. So that only the HCR is independently corrected without affecting the vertical deflection field, and thus without changing the VCR. Also, when assembling the electron gun, after welding the magnetic pieces (32a) (32b) to the inner electrode plate (7a) and (7b), annealed, then each grid (G ₁₎ ~
(G _5), each electrode of the electrostatic convergence diene scan means (6) (7
a) to (7d) are held in a jig and beaded. Therefore, the magnetic property of the magnetic piece (32) is stabilized by this annealing treatment, and the misconvergence property, that is, (HC
R) becomes stable.

〔Example〕

Hereinafter, embodiments of a cathode ray tube according to the present invention will be described with reference to the drawings.

In FIG. 1, (11) shows a cathode ray tube as a whole, (12) a striped color phosphor screen in which each of red, green and blue phosphors formed on the inner surface of the panel is formed in a stripe shape, ) Is a color selection electrode, for example, an aperture grill, disposed opposite to the color phosphor screen, and (10) is an internal conductive film. (14) is an electron gun arranged in the neck (9). In this electron gun (14), for example, three cathodes K, [(Kr), (Kg), (Kb)] corresponding to red, green and blue are arranged in a horizontal plane, and a common first grid
G ₁ , second grid G ₂ , third grid G ₃ , fourth grid
G ₄ and a fifth grid G ₅ are sequentially arranged coaxially, and an electrostatic convergence means (6) is arranged downstream of the fifth grid G ₅ . The electrostatic convergence means (6) comprises inner electrode plates (7a) and (7b) facing each other.
And an outer electrode plate (7
c) and (7d). And each beam (1R),
Third grid G ₃ and fourth grid for (1G) and (1B)
Common main electron lens is formed by G ₄ and the fifth grid G _5. Each of the beams (1R), (1G), and (1B) intersects and diverges at substantially the center of the main electron lens. 7b), the two-sided beams (1R) and (1B) pass between the opposed inner and outer electrode plates (7a) and (7c), and between (7b) and (7d), respectively. Phosphor screen (13)
Converged on above.

The inner electrode plate of the convergence diene scan means (6) (7a) and (7b) is applied the same anode voltage and the fifth grid G _5, the outer electrode plate (7c) and the high pressure of lower than the anode voltage in (7d) A convergence voltage is applied. A convergence-free deflection yoke (CFD) (1
5) is arranged. Further, U-shaped 1 made of permalloy fifth grid G ₅ side position of convergence diene scan means (6)
A pair of pole pieces, ie a pole piece for VCR correction (21)
[(21a) and (21b)] are welded.

In this embodiment, in particular, a chip-shaped HCR correction made of a flat magnetic piece, that is, a permalloy, is opposed to the inner surfaces of the open ends of the inner electrode plates (7a) and (7b) of the convergence means (6). Pole piece (32) [(32a)
(32b)] is attached by welding or the like.

As a specific example, in the development stage of the convergence-free deflection yoke, the VCR correction pole piece (21) [(21a) (21b)] to be attached to the electron gun (14) was determined, and various types of misconvergence were determined. When suppressed, the value of HCR at the X end of the screen is +0.05, and the horizontal deflection magnetic field is a pincushion magnetic field as a whole.
It became 0.13. This value is not sufficient in view of the variation in characteristics. Therefore, without changing the coil shape of the horizontal deflection magnetic field, as shown in FIG. 6, an HCR correction pole piece (32) made of 42NiFe permalloy having a length of a = 1 mm, a width of b = 1 mm and a thickness of t = 0.25 mm was used. Provide this pole piece (32)
Was attached to the center of the inner surfaces of the open ends of the inner electrodes (7a) and (7b) of the convergence means (6) as shown in FIG. As a result, the HCR is shifted to the negative side without affecting the VCR.
0.1mm could be corrected. By this, HCR of the screen X edge
= −0.06, HCR at the corner = + 0.04, and the convergence characteristics were improved.

Also, as shown in FIG. 4, the inner electrode plates (7a) and (7b)
Two pairs of pearl pieces (32
a) By attaching (32b), the HCR can be corrected to the plus side.

Before assembling the electron gun, the HCR correction pole piece (32) and the VCR correction pole piece (21) are welded to the inner electrode plates (7a) (7b) of the electrostatic convergence means (6). Anneal at 1200 ° C in ₂ atmospheres.
Then, through the jig, the first grid G ₁ ~ fifth grid
G ₅ , outer electrode plates (7c) (7d) and inner electrode plates (7a) (7
b) Assemble and beading to assemble the electron gun. Among the jigs, as shown in FIG. 7, the inner electrode plate (7a)
The jig or center spacer (33) sandwiched between (7b) and (7b) should be removed from the HCR so that it can be removed after the beading process.
A groove (34) for escaping the correction pole piece (32) is provided.

According to the configuration described above, the VCR is affected by attaching the chip-shaped HCR correction pole piece (32) to the inner surfaces of the open ends of the inner electrode plates (7a) and (7b) of the electrostatic convergence means (6). , It is possible to independently correct only the HCR. In particular, at the development stage of a cathode ray tube equipped with a convergence-free deflection yoke, the VCR correction pole piece (21) was determined to minimize various misconvergences, and then the coil shape of the horizontal deflection magnetic field of the deflection yoke was changed. HCR can be corrected without any change. By the way, if the magnetic field on the deflection yoke side is changed in order to correct the HCR, the landing pattern of the beam changes, and other elements must be changed significantly, delaying the development of the cathode ray tube. However, according to the present invention, the HCR can be corrected without changing other elements.

In addition, since the HCR correction pole piece (32) has a small shape, it is possible to weld the inner electrode plates (7a) and (7b) alone before the electron gun assembling process (so-called beading process). Annealing can be performed after welding. This stabilizes the magnetic characteristics of the pole piece (32) and stabilizes the misconvergence characteristics (ie, HCR). Furthermore, there is no need to attach the HCR correction pole piece (32) to the beaded electron gun,
The workability is not deteriorated and the electron gun is not deformed.

〔The invention's effect〕

According to the present invention, the VCR, which has been adjusted in advance, is mounted on the inner surface of the open end of the second electrode plate, that is, the inner electrode plate of the electrostatic convergence means of the electron gun.
Only the HCR can be corrected without affecting other types (other than the HCR) such as misconvergence, that is, without adjusting the convergence-free deflection yoke.
Therefore, it is easy to develop a cathode ray tube having a convergence-free deflection yoke or a pin-free deflection yoke.
In addition, before the electron gun assembling process, the HCR correction magnetic small piece is welded to the inner electrode plate for annealing, so that the magnetic properties of the magnetic small piece are stabilized, and the misconvergence (ie, HC)
R) becomes stable.

[Brief description of the drawings]

1 is a sectional view showing an example of a cathode ray tube according to the present invention, FIG. 2 is a perspective view showing an example of an electron gun according to the present invention, and FIG. 3 shows a magnetic field distribution applied to the electron gun of FIG. FIG. 4 is a perspective view showing another example of the electron gun according to the present invention, FIG. 5 is a diagram showing a magnetic field distribution applied to the electron gun of FIG. 3, and FIG. 6 is an HCR correction according to the present invention. FIG. 7 is a perspective view showing an example of an assembly jig, FIG. 8 is a perspective view showing an example of an inner electrode plate of an electrostatic convergence means,
FIG. 9 is a plan view showing the longitudinal misconvergence and the transverse misconvergence of the center beam, and FIG.
FIG. 11 is a perspective view showing an example of a conventional electron gun, FIG. 11 is a plan view thereof, and FIG. 12 is a perspective view of a main part showing another example of the conventional electron gun. (6) is an electrostatic convergence means, (11) is a cathode ray tube, (14) is an electron gun, (21a) and (21b) are VCR correction pole pieces, (24a) (24b) (32a) (32b) It is a pole piece for HCR correction.

Claims (1)

(57) [Claims] An electron gun provided with a pair of first electrode plates, a pair of second electrode plates disposed in parallel between the first electrode plates, and an electrostatic convergence means provided at a subsequent stage, and a deflection yoke. A cathode ray tube comprising: a flat plate-shaped magnetic piece arranged in parallel with the second electrode plate on an inner surface of an open end of the second electrode plate.