JPH0318293B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a color picture tube device, and in particular to magnetization,
The present invention relates to a color picture tube device incorporating a demagnetizable permanent magnet member and a shadow mask.

A shadow mask type color picture tube device has a structure as shown in FIG.

That is, due to the impact of the electron beam on the inner surface, red,
A face plate 1 on which a phosphor screen 2 in which a phosphor layer emitting light in each color of green and blue is regularly arranged in a dot shape or a band shape is adhered, and the inner wall of a side wall portion 1 ₁ of this face plate 1 is implanted. A plurality of panel pins 5, a spring 6, and a mask frame 4 are connected to each other.
A shadow mask 3 having a plurality of openings 3a, which are electron beam passing holes, arranged opposite to the phosphor screen 2 at predetermined intervals through the phosphor screen 2, and a mask frame 4.
an inner shield 14 disposed on the side wall ₁₁ , a color picture tube connected to the net 9 which houses the electron gun 10 via a funnel 7 on the side wall ₁₁ ; It consists of a deflection device 8 attached to the outer wall of the funnel 7 via a wedge 8 ₂ and an adjustment magnet 11 attached to the outer wall of the funnel 9, and directs the electron beam 13 emitted from the electron gun 10 to the opening. It is made to strike a predetermined phosphor layer of the phosphor screen 2 through the phosphor 3a to reproduce a color image. In this case, in an unadjusted color picture tube device, due to assembly errors, errors in each component, etc., the electron beam 13 usually does not strike a predetermined phosphor layer correctly, but instead strikes another phosphor layer, often resulting in color mixture or errors. Landing occurs and correct color reproduction is not performed.

Generally, the main factor that determines the color reproducibility of a color picture tube device in which a shadow mask is installed is the mounting accuracy of the shadow mask 3 through its support structure, ie, panel pins 5, springs 6, and mask frame 4. Among these, the shadow mask 3 is usually made of an approximately 0.15 mm steel plate formed into a predetermined curvature, but this alone lacks mechanical strength, so it is reinforced with a frame called a mask frame 4, which is part of the support structure. It has been done. Although the above-mentioned structure is generally in practical use, it cannot be said that the color reproducibility or precision is sufficient. In particular, if mechanical force is applied during the assembly process of the color picture tube body after the phosphor screen is formed, the relative relationship between the opening 3a of the shadow mask and the phosphor layer forming the phosphor screen 2 may be "shifted" or deformed. This can cause problems. This deformation or “slippage”
is about 10μ to 30μ, which is not a very large amount, but the impact position of the electron beam 13 on the phosphor layer is affected by geomagnetism, etc. It comes differently. Thus, for example, after adjusting a color receiver,
When the installation position of this color receiver is changed so that the face plate 1 faces north or south, color reproducibility may deteriorate.

The above-mentioned problems can be solved with conventional technology,
For example, when adjusting a color picture tube device, the problem can be solved by adjusting the deflection device 8 with a wedge 8 ₂ and optimally adjusting the adjustment magnet 11.

However, in recent years, even in color picture tube devices, adjustments have been made as easily as in monochrome picture tubes, that is, when the deflection device 8 is fixed in a state pressed against the funnel 7 via the neck 9, the adjustment has already been completed. Recently, there has been a demand for a picture tube device of the type shown in FIG.

Although a picture tube like the one described above is theoretically possible, it is extremely difficult in practice. The reason for this is that, as mentioned above, there is always some "misalignment" or deformation in the shadow mask 3, and in addition, the dimensional accuracy of the face plate 1, funnel 7, net 9, electron gun, deflection device 8, etc. This is because there are "variations" in the characteristics.

As a method for solving the various drawbacks of the conventional color picture tube device, the applicant has previously developed a color picture tube as shown in FIG.

Next, an example will be explained with reference to FIG. In the figure, the same parts as in the conventional example are indicated by the same reference numerals, and will not be particularly described.

That is, the annular plate body 2 made of a permanent magnet member is supported by the inner shield 24 via the fixing part 25.
6 is provided, and a predetermined portion of this annular plate body 26 is magnetized or demagnetized by a coil 27 provided outside the tube to prevent mislanding of the electron beam. However, as a result of various experiments on such a color picture tube device, we found that the annular plate 26
By adjusting the mislanding, the linearity of the screen is lost and the screen is distorted. In this case, the linearity distortion varies depending on the individual tubes, so it is unpredictable.

This phenomenon will be explained with reference to FIG. In this figure, only the central electron beam is illustrated to simplify the explanation.

That is, an electron beam emitted from an electron gun (not shown) is deflected by a deflection device (not shown). If the intersection point O between the trajectory of the deflected electron beam and the central axis Z of the color picture tube is called the deflection center 28, then when the deflection center is O, the deflected electron beam 30 will move toward the opening 3a of the shadow mask 3. through,
The light hits the Z ₀ point on the phosphor layer 34 that emits a predetermined color. Next, consider the case where the deflection center shifts to O', that is, 29, due to assembly errors of the color picture tube or parts errors.The electron beam 3 deflected at the deflection center O'
When light 1 passes through the opening 3a of the shadow mask 3, it is incident on point _Z1 of the phosphor screen 2. In this case, since the electron beam 31 is not correctly incident on the phosphor layer, the color purity of the color image reproduced on the phosphor screen 2 deteriorates. The annular plate 2 attached to the inner shield 24 described above has such mislanding.
6, if the position of the magnetic field to be corrected is on the dashed-dotted line 33, then the electron beam 32 shown by the dashed-dotted line deflected at O' is the same as the electron beam 30 when deflected at the deflection center O. It must be further deflected at the magnetic field position 33 so that it follows the same direction of travel, and it must strike the Z ₀ point. Since the electron beam 32 would be incident on the _Z2 point if no correction magnetic field existed, the pattern originally located at the _Z2 would move to the _Z0 point. Therefore, if the center axis Z of the tube is taken as the origin, the linearity will be distorted by Z ₂ −Z ₀ /Z ₀ . It is clear that this distortion becomes larger as the one-dot chain line 33, which is the deflection surface, approaches the net side, and the correction becomes easier as it approaches the net side.

In addition, other problems with the color picture tube device shown in FIG.
has a complicated shape, and these shapes differ in a complicated manner depending on the tube type. Therefore, even when the annular plate 26 is magnetized in the same way, the magnetic field is combined with the inner shield 24 and the mask frame 4, resulting in a complicated shape. Moreover, since the amount of landing correction differs depending on the individual tube, it is very difficult to calculate its influence in advance.

The present invention was devised in view of the above-mentioned drawbacks of the conventional art and the problems of the prior application, and it is possible to assemble and adjust a color receiver using the same adjustments as a black and white picture tube, and it also eliminates pattern distortion and It is an object of the present invention to provide a color picture tube device equipped with a permanent magnet member that can be easily magnetized without considering the complexity of the magnetic field.

Next, one embodiment of the color picture tube device of the present invention will be described with reference to FIG. In the drawings, the same reference numerals as those in the conventional art and the prior application indicate the same parts.

In other words, red, green,
A face plate 1 on which a phosphor screen 2 in which a phosphor layer emitting light in each color of blue is regularly arranged in a dot shape or a band shape is adhered, and the inner wall of a side wall portion ₁₁ of this face plate 1 is implanted. A shadow mask 3 having a plurality of openings 3a, which are electron beam passing holes, which are arranged opposite to each other at a predetermined distance from a phosphor screen 2 via a mask frame 4, and a mask frame. Inner shield 14 disposed on 4 and side wall portion 1 ₁
A color picture tube, to which a net 9 containing an electron gun 10 is connected via a funnel 7, is fixed to the outer wall of the net 9 by a support portion ₈₁ , and is mounted via a wedge ₈₂ between the outer wall of the funnel 7. The deflection device 8 is composed of a deflection device 8 and an adjustment magnet 11 attached to the outer wall of the net 9, and the electron beam 13 emitted from the electron gun 10 is directed to a predetermined phosphor layer of the phosphor screen 2 through the opening 3a. It is almost the same as the conventional color picture tube device in that it is designed to reproduce a color image by colliding with the phosphor. An annular permanent magnet member 36 having a shape or a linear shape is provided, and by magnetizing or demagnetizing a desired portion of the permanent magnet member 36 from outside the tube, the electron beam 13 can be accurately projected onto each phosphor layer. It is characterized by the fact that it is possible to do so. With this structure, since soft iron is used for the shadow mask 3, most of the magnetic flux from the magnetized permanent magnet member 36 is transferred to the shadow mask 3.
The landing of the electron beam on the phosphor screen is corrected by the magnetic field formed around the opening of the shadow mask by this magnetic flux, and does not spread to areas other than the shadow mask 3, such as the space between the shadow mask 3 and the phosphor screen 2. Therefore, the magnetic poles that generate the correction magnetic field of the electron beam 13 formed on the permanent magnet member 36 do not need to be magnetized in consideration of the influence of complicated magnetic fields due to magnetic coupling with the inner shield, mask frame, etc. Magnetization may be performed by considering only the magnetic coupling with 3. Since the shadow mask 3 has a simpler shape than the mask frame 4 and the inner shield 24, it has the advantage that desired magnetization can be easily achieved. Further, since the deflection of the electron beam for mislanding correction is performed at the position of the shadow mask 3, the distortion of the pattern on the screen is about the same as the amount of correction, at most several tens of μm, and is hardly a problem when visually observed.

To explain this phenomenon with reference to FIG. 5, an electron beam emitted from an electron gun (not shown) is deflected by a deflection device (not shown). If the intersection point O between the trajectory of the deflected electron beam and the central axis Z of the color picture tube is called the deflection center 28, then when the deflection center is O, the deflected electron beam 30 will move toward the opening 3a of the shadow mask 3. The light passes through and hits the Z ₀ point on the phosphor layer 34 which emits a predetermined color. Next, due to assembly errors of the color picture tube and errors in parts, the center of deflection may be
Considering the case where the deviation is O′, that is, 29, the center of deflection
The electron beam 31 that has been deflected at O' is at the aperture 3a
If the light passes through the phosphor screen 2, it will be incident on the _Z1 point of the phosphor screen 2. In this case, since the electron beam 31 is not correctly incident on the phosphor layer, the color purity of the color image reproduced on the phosphor screen 2 will be poor. If a magnetic flux 35 is generated at the position of the shadow mask 3, the electron beam 31 is deflected at the aperture 3a and moves from point _Z1 to point _Z0 on the phosphor screen 2, and the mislanding is corrected. At this time, the distortion of the pattern on the screen is at most several tens of micrometers, as mentioned above.
In practice, this is almost no problem.

This kind of correction method not only corrects the deviation of the deflection center, but also
Of course, the present invention can also be used for other types of mislanding such as mislanding due to shadow mask assembly error and electron gun assembly error.

Further, the permanent magnet member 36 used for this correction is preferably a metal magnet with a coercive force of about 100 oersteds, such as Spinodal, Baicaloy, Kiunico, Kiunihue, etc., and the shape of the permanent magnet member 36 may be such that it completely surrounds the outer edge of the shadow mask. However, it may be placed only at a desired position, for example, at a position corresponding to a magnetizing coil of a magnetizing device for magnetizing a permanent magnet member.

Furthermore, when magnetizing the permanent magnet member 36, since the color picture tube's inner shield, shadow mask, mask frame, etc. are made of soft iron, they are magnetized at the same time, and it is difficult to accurately detect whether or not the permanent magnet member is magnetized. Since it is almost impossible to magnetize or demagnetize a permanent magnet member, applying an attenuated alternating magnetic field having an initial peak value of, for example, 100-odd oersted, does not demagnetize the permanent magnet member. It is possible to remove the magnetization of the mask frame, and good characteristics can be obtained without substantially changing the magnetization of the permanent magnet member. That is, the sixth
As shown in the figure, a plurality of magnetizing coils 37 are arranged opposite to the permanent magnet member 36, and a predetermined strong DC current 38 is passed through each of the magnetizing coils 37 as shown in FIG. It is preferred to add a damped alternating current 39 after the strong current 38.

The method of magnetizing the permanent magnet member 36 described above can be applied as is to a color picture tube having a so-called outer shield, which has a magnetic shield on the outside.

As mentioned above, although the color picture tube device of the present invention has a simple structure, it can prevent mislanding, which is the most important problem in a picture tube device, and it can also achieve good performance without causing problems in cost, dimensional accuracy of parts, or characteristics. It is possible to create products with special characteristics,
In addition, distortion of the pattern during adjustment is hardly a problem, and since there is little magnetic coupling with a magnetic shield etc., the magnetization method is extremely simple, and its industrial value is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of a conventional color picture tube device, FIG. 2 is a cross-sectional view of a color picture tube device of the prior application, FIG. The figure is a sectional view of one embodiment of the color picture tube device of the present invention, FIG. 5 is an explanatory diagram of pattern distortion in the embodiment of FIG. 4, and FIG. The explanatory diagram, FIG. 7, is a curve diagram showing a current waveform for magnetization or demagnetization. 2... Fluorescent screen, 3... Shadow mask, 4...
Mask frame, 7... Funnel, 8... Deflection device, 10... Electron gun, 26, 36... Permanent magnet member.

Claims (1)

[Claims] 1. A face plate with a phosphor screen on its inner surface, which has a regularly arranged phosphor layer that emits red, green, and blue light when an electron beam hits it, is attached to an electron gun via a funnel. In a color picture tube device, in which a deflection device is attached to the outer wall from the neck to the funnel of the color picture tube in which at least a shadow mask is installed, the deflection device is attached to the outer edge of the effective surface facing the phosphor screen of the shadow mask. A permanent magnet member that can be magnetized or demagnetized from outside the tube is disposed in contact with the shadow mask so that the electron beam can impinge on the corresponding phosphor layer through the shadow mask. Color picture tube device.