JPH0982240A - Cathode ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the local distortion in the corner part of an image by selecting the sticking position of a magnet for landing correction on a specified line segment corresponding to the diagonal line on a face panel image plane. SOLUTION: A magnet(MG) 12 for landing correction is arranged on a second line segment which is parallel to a first line segment along the ridge line of a funnel 2 corresponding to the diagonal line of a face panel image plane passing through the center of a neck 3 and a deflection yoke 7, and shifted by the distance W on the inside in the X-X axis direction. By arranging the MG 12 in the position of the second line segment 18, the distortion amount in the vertical direction to the horizontal direction which is local distortion in the longitudinal direction of a lateral line of one measure of a cross hatching pattern of four corners of upper, lower, right, and left edges of an image is reduced to the maximum value of the landing correction amount. The local distortion of the image in the corner parts, and especially the local distortion amount in the vertical direction can be reduced.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cathode ray tube,
In particular, the present invention relates to a cathode ray tube configured to correct local distortion by attaching a landing correction magnet to the cathode ray tube.

[0002]

2. Description of the Related Art Conventional color cathode ray tubes (hereinafter C
As shown in FIG. 9B, RT is a peripheral device 10 including a face panel 1, a glass tube wall including a funnel portion 2 and a neck portion 3, and red (R) and green (G) formed on the inner surface of the face panel 1. ), A blue (B) three-color stripe (or dot) phosphor screen 4, and a color selection element body (shadow mask) having an electron beam passage slit arranged facing the screen 4 in the vicinity thereof. A color selection device 5 and an electron gun 6 which emits and focuses a plurality of electron beams disposed in the neck 3 are provided, and a saddle type deflection yoke (hereinafter DY) is provided near the boundary between the outer periphery of the neck 3 and the funnel portion 2. 7) is inserted.

The electron beam 8 which has passed through the slit of the color selection element of the color selection device 5 in the above-mentioned CRT is accurately landed on the phosphor stripe of the phosphor screen 4.

In this case, in order to make the electron beam 8 incident on the phosphor stripe correctly, for example, the center of the deflection yoke 7 corresponding to the diagonal line of the face panel screen of the peripheral device 10 viewed from the funnel portion 2 side of FIGS. 1 and 9B. A landing correction magnet (hereinafter referred to as MG) 12 is attached on a first line segment 11 along a funnel portion passing through.

The above-mentioned MG 12 is formed in a disk shape having a diameter of about 10 mm, and N pole and S pole are magnetized in the diameter direction.

Generally, as shown in FIG. 9B, a face panel 1
As indicated by arrow C, the electron beam 8A when the electron beam 8 mislandes to the left when viewed from the front side is called landing in the minus (-) direction, and the electron beam 8B when the electron beam 8 mislandes to the right side. Is called plus (+) direction landing.

With the above-described structure, the MG 12 is the face panel 1
In order to correct the mislanding of the corner portion of the screen displayed on the fluorescent screen of No. 1, a peripheral position in which the peripheral edge of the front opening of the deflection yoke 7 is viewed from the funnel side in order to correct the mislanding. As shown in FIG. 1 of FIG. 10, the reference position is set to zero, and the MG 12 is attached to the predetermined positions such that the distances L ₁ , L _2, ...
The orbit of is shifted so as to land in the + or-direction.

In FIG. 1, the distances L ₁ , L ₂ , L ₃ ... Are 20.
The state of being attached to the positions of mm, 40 mm, and 60 mm is shown, but these MG12 are usually the first in the first quadrant.
Only one is arranged on the line segment 11 of. Also, the second to the fourth
If the mislanding occurs on the first line segment 11 of the quadrant, the MG 12 is attached. Of course, MG12 cannot be attached without mislanding.

The landing shift amount of the MG 12 is increased as it approaches DY 7, but local distortion occurs at the screen corner.

[0010]

In order to inspect the local strain as described above, as shown in FIG. 9B, the transparent board 14 is fixed on the bezel 13 and the crosshatch pattern projected on the CRT is indicated by an arrow. Observe from the C direction.

FIG. 9A is a view of the crosshatch 15 on which the CRT is projected through the transparent board 14 from the direction of arrow c, and a black frame double frame 16 is displayed in the effective screen of the transparent board 14.
Is engraved with a width of about 2 mm. If the corner portion of the cross hatch pattern 15 does not protrude from the frame 16, it is treated as a normal local distortion.

FIG. 10 is an enlarged view of the D portion of the corner portion of the cross hatch pattern 15 of FIG. 9A. In this case, one example of the local distortion in the cross hatch pattern 15 at the corner portion is shown, but this example is the local distortion that occurs when the landing is corrected in the-direction. The size of one cross of the cross hatch pattern 15 in the horizontal and vertical directions is 38 mm × 38 mm.

The interval between the straight line drawn horizontally and vertically from the peak point 17 of the local strain and the outer frame of the crosshatch pattern 15 at the point where the straight line is set horizontally and vertically at 38 mm is set in the vertical direction with respect to the horizontal direction. The amount of strain (hereinafter referred to as 1H-V) is defined as the amount of strain in the horizontal direction with respect to the vertical direction (hereinafter, 1V-V).
-H)), the horizontal distortion amount indicated by 1V-H can be corrected to some extent by an electric circuit or the like.
The amount of distortion in the vertical direction indicated by H-V is determined by the combination of CRT and DY7 and there is no correction means.
The local strain of must be minimized.

Further, in the + direction landing, the local strain is not a convex shape as shown in FIG. 10 but a concave shape.
The strain amount of HV and 1V-H can be measured.

The subject of the present invention is 1H-V and 1 as described above.
The present invention intends to provide a CRT which is designed to minimize the amount of VH distortion.

[0016]

According to the present invention, on a funnel 1 of a cathode ray tube, a first line segment 11 parallel to a first line segment 11 along a funnel 2 corresponding to a diagonal line of a screen is moved toward a horizontal axis. The landing correction magnet 12 is disposed on the second line segment 18.

According to the CRT of the present invention, the sticking position of the MG 12 is selected on the line segment 18 which is translated inward of the first line segment 11 corresponding to the diagonal line of the face panel screen, so that the image local at the corner portion is selected. It is possible to reduce distortion, especially the amount of local distortion in the vertical direction.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION The cathode ray tube (CR of the present invention will be described below.
T) will be described in detail with reference to FIGS. FIG. 1 is a block diagram of a CRT according to the present invention, which is viewed from the funnel 2 side of a peripheral 10 formed of a glass tube wall, and a deflection yoke (DY) 7 is fitted to a neck 3. ing.

The first line segment 11 along the ridgeline of the funnel corresponding to the diagonal line of the face panel screen passing through the center of the neck 3 and DY7 and the high voltage anode on the vertical Y axis passing through the center of the neck 3 and DY7. If the button portion 19 is provided and the horizontal direction orthogonal to the Y axis is the X axis, the conventional landing correction magnet (MG) 12 sets the peripheral end position of the front opening of the DY 7 to the reference position zero, and the first line. MG12 is affixed to predetermined positions of distances L ₁ , L ₂ , L _3, ... Along the minute 11, but in the first quadrant divided by the X and Y axes in this example, the first line segment 11 is X- The MG 12 is arranged on the second line segment 18 that is translated inward in the X-axis direction by a distance W corresponding to one MG 12.

The MG 12 used in this example is formed into a disk shape with, for example, a ferrite having a diameter of 10 mmφ as shown in FIG. 2, and the X'and Y'axes of the Y'axis passing through the center of the disk are attached as shown in FIG. The position of α degrees rotated from the Y ′ axis when the first line segment 11 or the second line segment 18 of the position is vertically aligned is N degrees.
And S poles are opposite axes.

Therefore, in this example, the parallel movement distance between the first line segment 11 and the second line segment 18 is W = 10 mm.

In FIG. 3, the MG 12 is shown as attached to the first line segment 11, but the polarity of the MG at the time of maximum correction in the + or − direction landing is the first line segment 11 or the second line segment. The opposing axes of the magnetic poles N and S of the MG 12 are arranged so as to be orthogonal to the line segment 18, and the MG 12 is attached at a position distant from the DY 7 in order to reduce the influence of image distortion as much as possible.

FIG. 4 shows the influence of the landing correction amount (hereinafter referred to as L / D) of the electron beam 8 by the magnetic field B of the MG 12 attached to the second line segment 18 of the funnel 2. Since the magnetic flux directed in the direction receives a force in the direction indicated by arrow f, L / D is shifted in the + direction.

In FIG. 1, on the second line segment 18 of the first quadrant divided by the X and Y axes, the distance L ₁ ′ from DY 7 as shown in FIG.
In the case where there is local distortion in the upper left corner of the screen as shown in FIG. 3, the first line segment 11 in the second quadrant is translated downward by the width W toward the X axis. The MG 12 is attached to the position of the distance L ₂ ′ from the opening end of the DY 7 on the second line segment 18 thus formed.

Similarly, when there are local distortions in the lower left and right corners of the screen, the first line segment 11 in the third and fourth quadrants is similarly translated to the second line upward by the width W in the X axis. D on minute 18
MG at positions L ₃ ′ and L ₄ ′ from the opening end of Y7
12 may be attached.

[0026]

EXAMPLES L ₀ of the second segment 18 position of the L ₀ ~L ₂ position as well as conventional first line segment 11 of the present invention in FIGS. 5 and 7 to
The result of measuring the landing correction amount (μm) and the local strain values of 1H-V and 1V-H when the MG 12 is arranged at the L ₃ position, that is, the strain amount of one cross hatch in the upper left corner of the screen. Indicates.

In this example, a 17-inch CRT is used, and the L / D point is -135 mm in the X-axis direction from the screen center and +103 mm in the Y-axis direction at the upper left corner of the screen, and the image size during image distortion measurement is H = 293 mm. V = 234 mm.

In FIGS. 5 and 7, the distances L ₀ = ₀ mm and L ₁ =
The case where the opposing axis of the magnetic pole of the MG12 shown in FIG. 2 at 20 mm, L ₂ = 40 mm, and L ₃ = 60 mm is rotated counterclockwise with reference to the rotation angle α is shown as a minus (−) angle. is there.

As can be seen from FIGS. 5 and 7, the landing correction amount L / D shows a larger value as the MG12 is attached to a position closer to DY7, for example, L ₀ = ₀ mm, α = −
At 45 °, L / D is 12.9, L ₁ = 20 mm, α = −
At 45 °, L / D is 10.8, L ₂ = 40 mm, α = −
At 45 °, L / D gradually decreases to 0. Also L /
The value of-in D indicates the case of landing in the-direction as described above.

Similarly, for example, MG12 with α = −45 °
Vertical local distortion 1H-V in the horizontal direction of the image at the rotation position of
Is L ₀ = ₀ mm is −0.1 (conventional example −2.06), L ₁
= -0.25 at 20 mm (conventional example-1.04), L ₃ =
At 40 mm, it tends to be small as -0.03 (conventional example -0.55).

That is, at each distance L from DY7, 1 of the crosshatch pattern 15 at the four corners of the upper, lower, left and right edges of the image is displayed.
It can be seen that 1H-V, which is the local distortion in the vertical direction of the horizontal line of the square, is reduced at the maximum landing correction amount by disposing the MG 12 at the position of the second line segment 18.

Incidentally, 1V-H affected by the landing correction at the corner portion, that is, 1V-H which is a local distortion in the horizontal direction of one vertical line of the cross hatch pattern 15 of the image, is also a conventional pasting position. However, these changes can be electrically corrected by the correction circuit included in the television deflection circuit.

FIGS. 6 and 8 show L ₁ = 20 of FIGS. 5 and 7.
The relationship between the rotation angle α and the local strain of the MG 12 in mm in the present example and in the related art is plotted. As indicated by the solid curve 20 for 1H-V and the broken curve 21 for 1V-H, it can be seen that the local distortion is reduced in the characteristic curve of FIG.

[0034]

According to the cathode ray tube of the present invention, 1H-V and 1V- can be obtained only by changing the attaching position of the landing correction magnet from the first line segment position to the moved second line segment position.
Since the local distortion in the H direction can be reduced, it is possible to obtain a cathode ray tube capable of improving the image quality level by eliminating the image distortion at the corner portion.

[Brief description of drawings]

FIG. 1 is a configuration diagram for explaining a magnet installation position of a cathode ray tube according to the present invention.

FIG. 2 is an explanatory diagram of a sticking direction of a landing correction magnet used in the cathode ray tube of the present invention.

FIG. 3 is an explanatory diagram of a landing correction magnet attachment position in each quadrant of the cathode ray tube of the present invention.

FIG. 4 is a diagram for explaining the influence of the landing correction magnet of the cathode ray tube of the present invention on the electron beam.

FIG. 5 is a diagram showing change data of local distortion and landing correction amount due to the landing magnet of the cathode ray tube of the present invention.

FIG. 6 is a characteristic curve diagram showing the relationship between the rotation angle (α) of the landing magnet of the cathode ray tube of the present invention and the local strain.

FIG. 7 is a diagram showing change data of local distortion and landing correction amount by a landing magnet of a conventional cathode ray tube.

FIG. 8 is a characteristic curve diagram showing a relationship between a rotation angle (α) of a landing magnet of a conventional cathode ray tube and a local strain.

FIG. 9 is an explanatory diagram of a conventional local strain inspection method.

10 is an enlarged view of a portion D of FIG. 9 and is an explanatory view of local distortion.

[Explanation of symbols]

 1 Face Panel 2 Funnel 4 Phosphor Screen 8 Electron Beam 10 Perimeter 11 First Line Segment 12 Landing Correction Magnet 14 Transparent Board 15 Crosshatch 18 Second Line Segment

Claims (2)

[Claims] 1. On a funnel of a cathode ray tube, landing correction is performed on a second line segment which is parallel to a first line segment along the funnel corresponding to a diagonal line of a screen and which is moved toward a horizontal axis. A cathode ray tube comprising a magnet for use. 2. The landing correction magnets are arranged along a second line segment, which is a parallel translation of the first line segment based on the peripheral edge of the opening of the deflection yoke fitted to the neck. The cathode ray tube according to claim 1, wherein