JP2001229854A - Deflection yoke and display apparatus using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deflection yoke for allowing an improvement in displayed image quality and a display apparatus provided with the deflection yoke. SOLUTION: This deflection yoke comprises a pair of horizontal deflection coils 10a, 10b for generating a horizontal deflection magnetic field that deflects an electron beam in a direction of a horizontal axis H, a pair of vertical deflection coils for generating a vertical deflection magnetic field that deflects the electron beam in a direction of a vertical axis V, a ferrite core formed of magnetic material, a pair of correction magnets 16a, 16b for generating a correcting magnetic field that corrects the orbit of the electron beam, and electromagnetic coils 17a and 17b for generating a magnetic field in a direction opposite to the correcting magnetic field generated by the correction magnet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a deflection yoke and a display device using the same, and more particularly, to a deflection yoke mounted on a cathode ray tube for displaying an image.

[0002]

2. Description of the Related Art In recent years, a display device has a large screen and a flat screen. In particular, when the screen is flattened, the conventional deflection yoke has a problem that the raster distortion becomes large and sufficient correction cannot be performed.

As shown in FIGS. 12 and 13, a conventional deflection yoke is composed of a pair of upper and lower (on the vertical axis V) horizontal deflection coils 5 mounted inside an injection-molded mold 51.
0a and 50b, a pair of left and right (on the horizontal axis H) vertical deflection coils 53a and 53b attached to the outside of the mold 51, and a ferrite core 5 formed of a magnetic material.
4, a pair of upper and lower correction magnets 55a and 55b for correcting raster distortion, and a pair of upper and lower correction elements 56 for correcting convergence of the electron beam.

For example, as shown in FIG. 14, when the raster distortion 34 at the peripheral portion of the screen and the raster distortion 35 at the intermediate portion of the screen are of a pincushion type with respect to the reference frame 35, the conventional deflection yoke is The principle of correcting distortion will be described. As shown in FIG. 15, the correction magnet 55a forms a leftward magnetic field when viewed from the opening side of the deflection yoke, that is, from the phosphor screen side. In addition,
In FIG. 15, the action of the magnetic field in the third and fourth quadrants is substantially the same as that in the first and second quadrants, so that the illustration is omitted for convenience.

As shown in FIG. 15, the electron beam 42 deflected to the peripheral portion of the screen is subjected to a Lorentz force acting upward in the vertical axis V according to Fleming's law by the magnetic field 36 formed by the correction magnet 55a. F
Receive H. Similarly, the electron beam 44 deflected to the screen middle receives a Lorentz force FL acting upward in the vertical axis V direction by the magnetic field 36. Electron beam 4
4 is a correction magnet 55a compared with the electron beam 42.
Is large, the magnitude of the acting Lorentz force FL is also smaller than the Lorentz force FH. That is, FH>
FL. For this reason, the correction amount of the pincushion-type raster distortion 35 in the middle portion of the screen is smaller than the correction amount of the pincushion-type raster distortion 35 in the peripheral portion of the screen.

Further, since the correction magnets used mainly for correcting the raster distortion have individual differences in the amount of magnetization of the correction magnets, the Lorentz forces FH and FL are not always constant.
Also, the ratio of these Lorentz forces is not always constant.

Accordingly, as shown in FIG. 16, even if the raster distortion 46 at the peripheral portion of the screen can be corrected in accordance with the reference frame 32, the pincushion-type raster distortion 47 at the intermediate portion of the screen cannot be corrected sufficiently. On the contrary, there is a possibility that the raster distortion of the pincushion type in the middle part of the screen is excessively corrected to the barrel type.

Further, as shown in FIG. 17, even if the raster distortion 49 in the middle of the screen can be corrected in accordance with the reference frame 32, the pincushion-type raster distortion 48 in the periphery of the screen.
May be excessively corrected to a barrel type, and conversely, pincushion type raster distortion at the periphery of the screen may not be sufficiently corrected.

For this reason, it is difficult for the conventional technique to simultaneously correct raster distortions in both the peripheral portion and the intermediate portion of the screen.

[0010]

As described above, the conventional correction magnet has an individual difference in the amount of magnetization, and the Lorentz acting on the electron beam deflected to the peripheral portion of the screen and the intermediate portion of the screen. The magnitude of the force varies. Therefore, even if the raster distortion in the peripheral portion of the screen can be corrected, there is a possibility that the raster distortion in the intermediate portion of the screen remains. Further, even if the raster distortion in the middle part of the screen can be corrected, there is a possibility that the raster distortion in the peripheral part of the screen remains.

Therefore, it is difficult to simultaneously correct the raster distortion in both the peripheral portion and the intermediate portion of the screen.
The problem of deteriorating the quality of the displayed image occurs.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above-described problems, and has as its object to provide a deflection yoke capable of improving the quality of a display image and a display device having the deflection yoke. It is in.

[0013]

According to another aspect of the present invention, there is provided a deflection yoke including a pair of horizontal deflection magnetic fields for generating a horizontal deflection magnetic field for deflecting an electron beam in a horizontal axis direction. A coil, a pair of vertical deflection coils for generating a vertical deflection magnetic field for deflecting the electron beam in the vertical axis direction, a ferrite core formed of a magnetic material, and a pair of corrections for generating a correction magnetic field for correcting the trajectory of the electron beam. A magnet, and an electromagnetic coil for generating a magnetic field in a direction opposite to a correction magnetic field generated by the correction magnet.

According to a fifth aspect of the present invention, there is provided a display device for connecting an electron gun assembly for generating an electron beam, a neck for enclosing the electron gun assembly, a panel having a phosphor screen therein, and the neck and the panel. An envelope having a funnel, a deflection yoke mounted on an outer surface of the funnel,
Wherein the deflection yoke includes a pair of horizontal deflection coils for generating a horizontal deflection magnetic field for deflecting the electron beam in the horizontal axis direction, and a pair of horizontal deflection coils for generating a vertical deflection magnetic field for deflecting the electron beam in the vertical axis direction. A vertical deflection coil,
A ferrite core formed of a magnetic material, a pair of correction magnets for generating a correction magnetic field for correcting the trajectory of the electron beam, and an electromagnetic coil for generating a magnetic field in a direction opposite to the correction magnetic field generated by the correction magnet, It is characterized by having.

[0015]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a deflection yoke according to an embodiment of the present invention;

As shown in FIG. 1, a display device having a deflection yoke according to the present invention, that is, a color cathode ray tube device, includes an in-line type electron gun assembly which emits three electron beams arranged in a row in a horizontal direction H. I have.

This color cathode ray tube apparatus includes a panel 101
, A neck 105, and a funnel 102 connecting the panel 101 and the neck 105.

The panel 101 is formed in a substantially rectangular shape having a major axis in the horizontal direction H and a minor axis in the vertical direction V, and emits red (R), green (G), and blue (B) light on its inner surface. And a phosphor screen 103 composed of a striped or dot-shaped three-color phosphor layer and a metal back layer. Further, this color cathode ray tube device has a shadow mask 104 mounted at a position facing the phosphor screen 103 at a predetermined interval. The shadow mask 104 has a large number of apertures inside the shadow mask 104 for passing an electron beam.

The neck 105 is formed in a substantially cylindrical shape having a central axis coinciding with the tube axis Z, and has a substantially circular cross-sectional shape. The neck 105 has three electron beams 106B and 106 arranged in a line in a line on the same horizontal plane.
An electron gun structure 107 for emitting G and 106R is provided.

These three electron beams 106G, 106B,
106R are arranged in a row in the horizontal direction H, and are discharged along a direction parallel to the tube axis direction Z. Of the three electron beams,
The electron beam 106G as the center beam travels on the trajectory closest to the center axis of the neck 105. Also,
Electron beams 106B, 10 as a pair of side beams
6R travels on the trajectory of both sides of the center beam 106G.

The electron gun assembly 107 focuses the three electron beams 106R, 106G, and 106B on the phosphor screen 103, and simultaneously
The three electron beams converge on the phosphor screen 103 surface.

This color cathode ray tube device has a deflection yoke 108 mounted outside the funnel 102 and an external conductive film 113 formed outside the funnel 102.
And an internal conductive film 117 formed on the inner surface extending from the funnel 102 to a part of the neck 105. The internal conductive film 117 is electrically connected to an anode terminal for supplying an anode voltage.

In the color cathode ray tube device having such a structure, the three electron beams 10 emitted from the electron gun
6B, 106G and 106R are deflected while self-concentrating by an asymmetric magnetic field composed of a pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection magnetic field generated by a deflection yoke 108, The screen 103 is scanned in the horizontal direction H and the vertical direction V. Thereby, a color image is displayed.

The deflection yoke 108 applied to this color cathode ray tube apparatus has a pair of horizontal deflection coils 10a and 10b for forming a horizontal deflection magnetic field as shown in FIGS.
And a pair of vertical deflection coils 11 for forming a vertical deflection magnetic field.
a and 11b, a ferrite core 12 formed of a magnetic material, a holding mold 13 formed of an injection-molded resin, a pair of correction elements 14a and 14b for forming a correction magnetic field mainly for correcting convergence,
A pair of correction magnets 16a and 16b formed in a rod shape for mainly correcting raster distortion are provided.

The holding mold 13 is formed in a substantially conical shape with the tube axis Z as a central axis. This holding mold 13
As shown in FIG. 3, a pair of vertical deflection coils 11a are arranged on the outer horizontal axis H so as to face each other.
And 11b.

As shown in FIG. 4, the holding mold 13 has a pair of horizontal molds disposed to face each other on a vertical axis V inside thereof as viewed from the opening side, that is, the phosphor screen 103 side. It holds the deflection coils 10a and 10b. In addition, the holding mold 13 holds a pair of correction magnets 16a and 16b disposed on the vertical axis V inside thereof so as to face each other.

Vertical deflection coils 11a and 11b, and
The horizontal deflection coils 10a and 10b are used to rotate a metal mold composed of a male mold and a female mold processed into a predetermined shape at the same time or to fix the mold and wind an electric wire in a gap between the male mold and the female mold. Respectively to form a saddle shape.

The ferrite core 12 is used for the vertical deflection coil 1.
In order to prevent the deflection magnetic field formed by 1a and 11b from leaking outside, it is arranged so as to surround the vertical deflection coils 11a and 11b along the side surface of the holding mold 13.

The correction elements 14a and 14b are electromagnetic coils formed by winding electric wires around a U-shaped silicon steel plate. The pair of correction elements 14a and 14b are arranged at symmetric positions so as to face each other on the vertical axis V.

Further, as shown in FIG. 4, the deflection yoke 108 has a pair of electromagnetic coils 17a and 17b arranged on the vertical axis V so as to face each other. These electromagnetic coils 17a and 17b are formed by directly winding electric wires around each of the correction magnets 16a and 16b formed in a bar shape. The electromagnetic coils 17a and 17b are supplied with a current flowing in a predetermined direction, so that the correction magnets 16a and 16b are
A magnetic field opposite to the correction magnetic field formed by b is formed. The strength of the magnetic field formed by the electromagnetic coils 17a and 17b is adjusted by controlling the magnitude of the current flowing through the coils.

As shown in FIG. 5, the two electromagnetic coils 17a and 17b are connected to two vertical deflection coils 11a and 11b.
b is electrically connected in series. Therefore, these electromagnetic coils 17a and 17b are provided with the vertical deflection coil 1
A vertical deflection current flowing through 1a and 11b is supplied. Therefore, as the vertical deflection current supplied to the vertical deflection coils 11a and 11b increases, the vertical deflection magnetic field acting on the electron beam increases, and the deflection amount of the electron beam increases. That is, as the electron beam is deflected toward the periphery of the screen, the vertical deflection current increases.

As described above, when the raster distortion in the middle portion of the screen is corrected only by the correction magnet having a strong magnetization amount, that is, a correction having a Lorentz force sufficient to correct the raster distortion in the middle portion of the screen. When a magnet is used, the electron beam deflected to the periphery of the screen approaches the correction magnet, and receives a strong Lorentz force due to the action of a stronger correction magnetic field, and is excessively corrected upward in the vertical axis V direction. For this reason, as shown in FIG. 6, the pincushion-type raster distortion 60 in the middle portion of the screen is corrected, but the pincushion-type raster distortion 61 in the peripheral portion of the screen becomes a barrel type and cannot be corrected.

On the other hand, as shown in FIG.
a forms a magnetic field 9 in the opposite direction to the correction magnetic field formed by the correction magnet 16a, that is, rightward when viewed from the opening side. Although the direction of the correction magnetic field is not shown in FIG. 7, the correction magnetic field is formed to the left from the direction of the magnetic pole of the correction magnet 16 a when viewed from the opening side. In FIG. 7, the action of the magnetic field by the correction magnet 16b and the electromagnetic coil 17b in the third and fourth quadrants is substantially the same as that in the first and second quadrants, and is not illustrated for convenience. I do.

As described above, since the electromagnetic coil 16a acts in a direction opposite to the direction of the correction magnetic field, it acts to weaken the intensity of the correction magnetic field. As described above, since the vertical deflection current is supplied to the electromagnetic coil 16a, as the deflection amount of the electron beam increases, the vertical deflection current increases, and the strength of the magnetic field formed by the electromagnetic coil 16a increases. It gets stronger.

As shown in FIG. 7, the electron beam 6 deflected to the periphery of the screen receives a Lorentz force FH2 acting downward in the vertical axis V direction by the magnetic field formed by the electromagnetic coil 16a. Further, the electron beam 8 deflected to the screen middle receives a Lorentz force FL2 acting downward in the vertical axis V direction by a magnetic field formed by the electromagnetic coil 16a. The magnetic field close to the electromagnetic coil 16a is
Because of the strong Lorentz force FH2, the Lorentz force FL2
Stronger.

For this reason, the electron beam 6 deflected to the peripheral portion of the screen receives a strong Lorentz force acting upward in the vertical axis V by the correction magnetic field, so that the pincushion-type raster distortion is excessively corrected, and the barrel is deformed. Although a type of raster distortion is generated, a strong Lorentz force acting downward in the vertical axis V direction is received by the magnetic field formed by the electromagnetic coil 16a, so that the barrel type raster distortion can be corrected.

The electron beam 8 deflected to the middle portion of the screen having a relatively small amount of deflection receives a strong Lorentz force acting upward in the vertical axis V by the correction magnetic field, thereby correcting the pincushion type raster distortion. . At this time, since the deflection amount of the electron beam 8 is relatively small, the vertical deflection current is relatively small, and since the electron beam 8 is relatively far from the electromagnetic coil 16a, Lorentz acting downward in the vertical axis V direction is used. The force has little effect on the electron beam 8. Therefore, the pincushion-type raster distortion in the middle portion of the screen is mainly corrected by the correction magnetic field formed by the correction magnet 16a.

That is, the raster distortion at the periphery of the barrel-shaped screen is corrected by weakening the correction magnetic field formed by the correction magnet 16a by the magnetic field formed by the electromagnetic coil 17a, and at the same time, the screen distortion is generated. The raster distortion of the portion is corrected mainly by the correction magnetic field formed by the correction magnet 16a, and it is possible to display a screen with less distortion.

In the above-described embodiment, the electromagnetic coil is wound directly around the correction magnet. However, this is not always necessary, and any position may be used as long as the electromagnetic coil forms a magnetic field in a direction to cancel the correction magnetic field. It may be arranged.

In the above embodiment, the electromagnetic coil 16 (a, b) is electrically connected to the vertical deflection coil 11 (a, b) in series as shown in FIG. 9
May be connected to the bridge circuit 18 shown in FIG. The bridge circuit 18 is formed by, for example, four diodes. The bridge circuit 18 rectifies the vertical deflection current supplied to the vertical deflection coils 11 (a, b) and supplies the current to the electromagnetic coils 16 (a, b). By appropriately selecting the impedance ratio of the diodes constituting the bridge circuit 18, the magnitude of the current supplied to the electromagnetic coils 16 (a, b) can be adjusted, and the magnitude of the magnetic field formed by the electromagnetic coils can be adjusted. The strength can be adjusted. For this reason, it is possible to simultaneously correct the raster distortion of the peripheral portion of the screen and the intermediate portion of the screen according to the amount of magnetization of the correction magnet.

Further, in the above-described embodiment, the current supplied to the two electromagnetic coils 16 (a, b) is constant, but in consideration of individual differences in the amount of magnetization of the correction magnet, It is also possible to adjust the balance of the ratio of the respective currents and individually adjust the strength of the magnetic field formed by the electromagnetic coil.

That is, the two electromagnetic coils 16 (a, b) shown in FIG.
b) is electrically connected in series. A variable resistor 19 functioning as an adjusting unit is connected to the two electromagnetic coils. By adjusting this resistance, it is possible to adjust the current flowing through each electromagnetic coil.

The two electromagnetic coils 16 shown in FIG.
(A, b) are connected in parallel with each other, and these are electrically connected in series to the two vertical deflection coils 11 (a, b). A variable resistor 19 functioning as an adjusting means is also connected to these electromagnetic coils 16 (a, b).

In the above description, the strength of the magnetic field generated by each electromagnetic coil is adjusted by controlling the current flowing through the electromagnetic coil using a bridge circuit, a variable resistor, or the like. The magnetic field generated by the electromagnetic coil may be adjusted by changing the number of turns.

As described above, since the current supplied to the electromagnetic coil for adjusting the intensity of the correction magnetic field can be adjusted individually, the correction magnetic field can be adjusted according to the variation in the amount of magnetization of the correction magnet. Can be adjusted.

As described above, according to the deflection yoke of the present invention and the display device having the deflection yoke, that is, the color cathode ray tube device, when an image is displayed on a flat screen, not only the peripheral portion of the screen but also the peripheral portion of the screen is displayed. It is possible to simultaneously correct the raster distortion in the middle part of the screen, and it is possible to improve the quality of the displayed image.

[0047]

As described above, according to the present invention, it is possible to provide a deflection yoke capable of improving the quality of a display image and a display device having the deflection yoke.

[Brief description of the drawings]

FIG. 1 is a sectional view schematically showing the structure of a display device provided with a deflection yoke according to the present invention.

FIG. 2 is a side view schematically showing a structure of a deflection yoke according to the present invention.

FIG. 3 is a rear view of the deflection yoke shown in FIG. 2;

FIG. 4 is a front view of the deflection yoke shown in FIG. 2;

FIG. 5 is a circuit diagram showing an electrical connection between the electromagnetic coil shown in FIG. 4 and a vertical deflection coil.

FIG. 6 is a diagram illustrating an example of a screen in which barrel-type distortion occurs at a peripheral portion of the screen when the pincushion-type raster distortion is corrected using only the correction magnet.

FIG. 7 is a diagram for explaining correction of a pincushion-type raster distortion by a correction magnet and an electromagnetic coil.

FIG. 8 is a diagram illustrating a screen on which pincushion-type raster distortion has been corrected.

FIG. 9 is another circuit diagram showing an electrical connection between the electromagnetic coil and the vertical deflection coil.

FIG. 10 is another circuit diagram showing the electrical connection between the electromagnetic coil and the vertical deflection coil.

FIG. 11 is another circuit diagram showing an electrical connection between the electromagnetic coil and the vertical deflection coil.

FIG. 12 is a side view schematically showing a structure of a conventional deflection yoke.

FIG. 13 is a front view of the deflection yoke shown in FIG.

FIG. 14 is a diagram for explaining a pincushion-type raster distortion.

FIG. 15 is a diagram for explaining correction of a pincushion-type raster distortion by a correction magnet.

FIG. 16 is a diagram illustrating an example of a screen in which a pincushion-type raster distortion remains in the middle of the screen when raster distortion in the peripheral area of the screen is corrected by the conventional deflection yoke using only the correction magnet. .

FIG. 17 is a diagram illustrating an example of a screen in which barrel-type raster distortion remains at the periphery of the screen when raster distortion in the middle of the screen is corrected by the conventional deflection yoke using only the correction magnet.

[Explanation of symbols]

 10 (a, b) horizontal deflection coil 11 (a, b) vertical deflection coil 12 ferrite core 13 holding mold 14 (a, b) correction element 16 (a, b) correction magnet 17 (a, b) b) Electromagnetic coil 108 Deflection yoke

Claims (5)

[Claims] A pair of horizontal deflection coils for generating a horizontal deflection magnetic field for deflecting the electron beam in the horizontal axis direction; a pair of vertical deflection coils for generating a vertical deflection magnetic field for deflecting the electron beam in the vertical axis direction; A ferrite core formed by the body, a pair of correction magnets for generating a correction magnetic field for correcting the trajectory of the electron beam, and an electromagnetic coil for generating a magnetic field in a direction opposite to the correction magnetic field generated by the correction magnet. A deflection yoke, comprising: 2. The deflection yoke according to claim 1, wherein the electromagnetic coil is wound directly around the correction magnet. 3. The deflection yoke according to claim 1, wherein the electromagnetic coil is electrically connected in series with the vertical deflection coil. 4. The deflecting device according to claim 1, wherein said deflection yoke further comprises an adjusting means for adjusting a ratio of a current flowing through each of said electromagnetic coils when a plurality of said electromagnetic coils are connected. yoke. 5. An electron gun assembly for generating an electron beam, an envelope having a neck for enclosing the electron gun assembly, a panel having a phosphor screen therein, and a funnel connecting the neck and the panel. A deflection yoke mounted on an outer surface of the funnel, wherein the deflection yoke comprises: a pair of horizontal deflection coils for generating a horizontal deflection magnetic field for deflecting the electron beam in a horizontal axis direction; A pair of vertical deflection coils that generate a vertical deflection magnetic field that deflects in the axial direction, a ferrite core formed of a magnetic material, a pair of correction magnets that generate a correction magnetic field that corrects the trajectory of the electron beam, and the correction magnet A display device, comprising: an electromagnetic coil that generates a magnetic field in a direction opposite to a generated correction magnetic field.