JP2002170504A - Deflection yoke and display device - Google Patents

Abstract

(57) [Summary] [Problem] To secure a desired XCV correction amount,
Reduce the inductance of the V correction coil. SOLUTION: A pair of horizontal deflection coils 16A and 16B connected in parallel, and a pair of horizontal deflection coils 16A and 16B are connected.
B and a pair of convergence correction coils 21A and 21B that are connected in series to each of the horizontal deflection coils 16A and 16B to vary the balance of current flowing through the pair of horizontal deflection coils 16A and 16B.
A and 16B are divided at coil intermediate portions T1 and T2, respectively, and the coil intermediate portions T1 and T2 are electrically connected to each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a cathode ray tube (CR)
Deflection yoke (DY) used to deflect an electron beam in a display device such as a television receiver or a computer display using T).
About.

[0002]

2. Description of the Related Art Generally, a display device using a cathode ray tube is:
A deflection yoke for deflecting the electron beam emitted from the electron gun up, down, left, and right is provided. The deflection yoke has a horizontal deflection coil and a vertical deflection coil, and is used by being mounted on a main body (glass bulb) of a cathode ray tube. In this deflection yoke, the horizontal deflection coil forms a horizontal deflection magnetic field that deflects the electron beam left and right (horizontal direction), and the vertical deflection coil forms a vertical deflection magnetic field that deflects the electron beam up and down (vertical direction). .

In such a display device, the three electron beams emitted from the electron gun are deflected up, down, left, and right by a deflection yoke, so that the spot of the electron beam is horizontally and vertically shifted on the fluorescent screen of the cathode ray tube. , A raster image is formed, and three electron beams are focused (convergence) at each scanning position, whereby a good image without color shift can be displayed. However, when a so-called convergence shift (hereinafter, referred to as “misconvergence”) in which the three electron beams do not converge on the phosphor screen occurs, this appears as a color shift or color unevenness on the screen.

Here, in an in-line type color cathode-ray tube in which an electron beam for emitting green phosphor is used as a center beam and each electron beam for emitting red and blue phosphors is used as a side beam, these three electrons are used. When the beam is deflected horizontally, as shown in FIG.
Misconvergence (hereinafter also referred to as “XCV”) may occur in which the positions of the electron beams (side beams) R and B corresponding to blue are shifted to cross on the horizontal axis of the screen. XCV is generated when the center position of the horizontal deflection magnetic field and the trajectory position of the electron beam are relatively displaced in the vertical direction. Factors that cause the XCV include an error in mounting the deflection yoke to the cathode ray tube, an error in mounting components in the deflection yoke, and a deviation in the winding distribution of the horizontal deflection coil.

As a means for correcting the XCV, a circuit configuration as shown in FIG. 10 is conventionally used. In FIG. 10, a pair of horizontal deflection coils 51A and 51B are arranged in pairs above and below (vertically) a deflection yoke, and are connected in parallel with each other. XCV correction coils 52A and 52B are connected in series to the pair of horizontal deflection coils 51A and 51B, respectively. Each of the XCV correction coils 52A and 52B is wound around a common bobbin to form a variable inductor.

In the above circuit configuration, when the inductance of the pair of XCV correction coils 52A, 52B is relatively changed (large or small), the balance of the current flowing in the pair of horizontal deflection coils 51A, 51B is correspondingly changed. Changes to When the current balance between the pair of horizontal deflection coils 51A and 51B changes, the center position of the horizontal deflection magnetic field changes in the vertical direction accordingly. Therefore, XCV can be corrected by appropriately adjusting the balance of the current flowing through the pair of horizontal deflection coils 51A and 51B with the XCV correction coils 52A and 52B.

[0007]

Since the XCV correction coils 52A and 52B do not contribute to the deflection of the electron beam, the inductance of the XCV correction coils 52A and 52B is reduced as much as possible in order to increase the deflection efficiency. Is more desirable. However, the XCV correction amount (correctable range) is determined by the inductance ratio of the XCV correction coils 52A and 52B to the inductance of the horizontal deflection coils 51A and 51B.
If the inductance of A and 52B is reduced, the XCV correction amount will be reduced accordingly. Therefore, conventionally, after securing a desired XCV correction amount, X
It was difficult to reduce the inductance of the CV correction coils 52A and 52B.

[0008]

A deflection yoke according to the present invention includes a pair of horizontal deflection coils connected in parallel, and a pair of horizontal deflection coils connected in series to each of the pair of horizontal deflection coils. It has a pair of convergence correction coils for varying the balance of flowing current, and has a configuration in which a pair of horizontal deflection coils are divided at respective coil intermediate portions and the coil intermediate portions are electrically connected to each other. . Further, the display device according to the present invention uses the deflection yoke having the above-described configuration.

In the deflection yoke having the above structure and the display device using the same, a pair of horizontal deflection coils are divided at the coil intermediate portions, and the coil intermediate portions are electrically connected to each other, so that the pair of horizontal deflection coils are electrically connected to each other. When varying the balance of the current flowing through the horizontal deflection coil with a pair of convergence correction coils, the inductance of the coil portion for which the current balance is to be varied is significantly reduced, and accordingly, the inductance of the convergence correction coil must be reduced accordingly. Becomes possible.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a schematic perspective view showing an overall image of a cathode ray tube according to the present invention. In FIG. 1, the main body (glass bulb) of the cathode ray tube 10 includes a panel section 11, a funnel section 12, and a neck section 13. On the inner surface of the panel section 11, a phosphor screen (not shown) in which red, blue, and green phosphors are arranged in a pattern is formed. On the other hand, an electron gun 14 serving as an emission source of an electron beam is provided in the neck portion 13. A deflection yoke 15 for deflecting the electron beam is mounted on a cone portion extending from the neck portion 13 to the funnel portion 12.

The cathode ray tube 10 having the above-described structure includes a panel portion 11
Along with various accessories necessary for reproducing a color image (or a black-and-white image) on the inner fluorescent screen, it is incorporated into a casing (not shown) together with a display device such as a television receiver or a computer display. You.

FIG. 2 is a side view including a partially broken cross section of the deflection yoke according to the present invention. In FIG. 2, the deflection yoke 15
Are equipped with components such as a horizontal deflection coil 16, a vertical deflection coil 17, a separator 18, a DY core 19, and a ring magnet 20. The horizontal deflection coil 16 is incorporated on the inner peripheral side of the separator 18, and the vertical deflection coil 17 is incorporated on the outer peripheral side of the separator 18. The separator 18 is made of an insulating material such as a resin, and has a substantially trumpet shape as a whole.

The horizontal deflection coil 16 is connected to the deflection yoke 1.
The vertical deflection coil 17 is wound in a pair on the left and right sides of the deflection yoke 15 in a saddle shape. Then, on the trajectory of the electron beam emitted from the electron gun 14, a pair of horizontal deflection coils 1
Numeral 6 generates a magnetic field (horizontal deflection magnetic field) for deflecting the electron beam left and right (horizontal direction), and a pair of vertical deflection coils 17 generates a magnetic field (vertical deflection magnetic field) for deflecting the electron beam up and down (vertical direction). . The vertical deflection coil 17 may be wound around the DY core 19 in a toroidal shape.

The DY core 19 is made of a magnetic material such as ferrite, and is formed in a substantially conical cylindrical shape having one opening in the direction of the center axis of the yoke larger than the other. This DY
The core 19 includes a horizontal deflection coil 16 and a vertical deflection coil 1.
In order to enhance the effect of the magnetic field generated by the, the deflecting coils 16 and 17 are mounted so as to cover them. The ring magnet 20 is used to correct the deflection yoke 1 in order to correct the trajectory shift of the electron beam due to an assembly error of the electron gun 14 or the like.
5 at the rear end.

FIG. 3 is a diagram showing a circuit configuration of a horizontal deflection system according to the embodiment of the present invention. In FIG. 3, a pair of horizontal deflection coils 16A and 16B are connected in parallel with each other. For a pair of horizontal deflection coils 16A and 16B,
A sawtooth current having a horizontal deflection period, that is, a horizontal deflection current Ih is supplied by a current supply means (not shown). An XCV correction coil 21A is connected in series to one horizontal deflection coil 16A of the pair of horizontal deflection coils 16A and 16B, and the other horizontal deflection coil 16B is used.
Is connected in series with an XCV correction coil 21B.
These XCV correction coils 21A and 21B vary the balance of the current (horizontal deflection current Ih) flowing through the pair of horizontal deflection coils 16A and 16B.

One horizontal deflection coil 16A has two coil portions 16A-1 and 16A with a coil intermediate portion T1 as a boundary.
-2. For example, the coil intermediate portion T1 temporarily winds a coil wire around a tap terminal in the course of winding of the horizontal deflection coil 16A, and then turns the coil wire from the tap terminal or another tap terminal electrically connected to the tap terminal. It is provided by restarting. Thus, assuming that the total number of turns of the horizontal deflection coil 16A is 100 turns, the coil portions 16A-1 and 16A-2 have a coil intermediate portion T1 at approximately half the number of turns (about 50 turns). Are almost equally divided. Similarly, the other horizontal deflection coil 16B is also divided into two coil portions 16B-1 and 16B-2 at the coil intermediate portion T2. Further, a pair of horizontal deflection coils 16A,
The coil intermediate portions T1 and T2 of the 16B are electrically connected to each other.

On the other hand, the XCV correction coil 21A
Are connected in series to one coil part 16A-2 (right side in the figure) of the horizontal deflection coil 16A divided at the coil middle part T1. Similarly, the XCV correction coil 21B has one (right-hand side) coil part 16B of the horizontal deflection coil 16B divided at the coil middle part T2.
-2 in series.

A pair of XCV correction coils 21A, 21B
Respectively constitute variable inductors. That is, the XCV correction coils 21A and 21B are connected to the pair of horizontal deflection coils 16A and 16B, for example, as shown in FIG. 4, while being wound on both sides of the hollow coil bobbin 22. A ferrite core 23 is inserted into the hollow portion of the coil bobbin 22. The core 23 is located in the hollow portion of the coil bobbin 22 in the direction of the central axis (the direction of the arrow in the drawing) M, N
It is movably guided and supported. A male screw (not shown) is formed on the outer periphery of the core 23. On the other hand, a rotary knob 24 is provided at an intermediate portion of the coil bobbin 22 in the center axis direction. A screw hole (female screw) (not shown) is formed in the center of the rotary knob 24, and a male screw of the core 23 is screwed into the screw hole.

In such a configuration, the rotary knob 24
Is rotated, the core 23 moves in the direction of the arrow M or the direction of the arrow N according to the rotation angle and the rotation direction. As a result, the insertion length of the core 23 with respect to each of the XCV correction coils 21A and 21B in the coil bobbin 22 changes relatively, and accordingly, the pair of XCV correction coils 2
Each inductance of 1A and 21B changes relatively.
That is, as the inductance of one XCV coil 21A increases, the other XCV correction coil 21A
B has a smaller inductance, and conversely, one XC
As the inductance of the V coil 21A decreases, the inductance of the other XCV correction coil 21B increases accordingly.

As described above, the XCV correction coils 21A, 21
When the inductance of B changes, the balance of the current flowing through the pair of horizontal deflection coils 16A and 16B changes accordingly. Thereby, the pair of horizontal deflection coils 16
Since the center position of the horizontal deflection magnetic field formed by A and 16B fluctuates in the vertical direction, misconvergence (XCV) as shown in FIG. 9 is corrected by appropriately adjusting the current balance. It becomes possible.

Here, in the present embodiment, a pair of horizontal deflection coils 16A and 16B
1, T2, and their coil intermediate portions T1, T2
2 are electrically connected to each other. Thereby, each coil part 16A-1, 16A-2, 16B-1, 16B-2 divided by coil middle part T1, T2.
Of the horizontal deflection coils 16A, 16B when the coil intermediate portions T1, T2 are not connected to each other.
Significantly smaller than the inductance of

More specifically, for example, the coil section 16A-
When the number of winding turns of each of the horizontal deflection coils 16A and 16B is set to about の of the number of winding turns of each of the horizontal deflection coils 16A and 16B, the relationship between the number of winding turns and the inductance (winding The number of wire turns is proportional to the parallel root of the inductance), so the coil portions 16A-1, 16A-2
Is about ４ of the inductance of the horizontal deflection coil 16A when the coil intermediate portions T1 and T2 are not connected to each other, and similarly, each of the coil portions 16B-1 and 16B-2 The inductance of
This is about ４ of the inductance of the horizontal deflection coil 16B when the coil intermediate portions T1 and T2 are not connected to each other.

On the other hand, the XCV correction amount is determined by the coil unit 16A-
It depends on the inductance ratio of the XCV correction coils 21A and 21B to the inductance of 2,16B-2. In this case, the inductance of the coil portions 16A-2 and 16B-2 is reduced as described above.
The horizontal deflection field is proportional to the ratio of the number of turns in the coil to the current, and the current is proportional to the square of the number of turns in the inductance ratio of the coil. Therefore, the XCV correction coils 20A and 20B are proportional to the square root of the inductance ratio between the horizontal deflection coils 16A and 16B and the coil portions 16A-2 and 16B-2 divided by the coil intermediate portions T1 and T2. By setting the inductance of XCV, it is possible to reduce the inductance of the XCV correction coils 20A and 20B as compared with the conventional case and to secure the same XCV correction amount as the conventional case.

Therefore, compared with the case where the coil intermediate portions T1 and T2 are not connected to each other, the XC required for providing the same current difference to the horizontal deflection coils 16A and 16B is obtained.
The inductance of the V correction coils 20A and 20B can be reduced. Further, the XCV correction coils 21A, 2
Comparing the case where the inductance of 1B is the same, it is possible to secure a larger XCV correction amount by interconnecting the coil intermediate portions T1 and T2. The reason is specifically described below.

FIG. 5 is a circuit diagram equivalently converted from the circuit shown in FIG. In this circuit diagram, respective coil portions 16A-1, 16B-1 of horizontal deflection coils 16A, 16B are shown.
, The inductance of each of the coil portions 16A-2,
The inductance of 16B-2 is L2, and the inductance of the XCV correction coils 21A and 21B is L3.
Assuming L4, the asymmetric current I1 flowing through the XCV coils 21A and 21B is expressed by the following equation (1).

[0027]

(Equation 1)

In the above equation 1, L2 + L3 = A,
L2 + L4 = B. Further, the resistance of the coil is ignored because it is sufficiently small with respect to the inductance, and the frequency jω of the inductance is also omitted.

The XCV correction is performed in the coil sections 16A-2 and 16B-2 through which the asymmetric current I1 flows. At that time, X
The CV correction amount is proportional to the product of the number of winding turns “Tm” of the coil units 16A-2 and 16B-2 and the asymmetric current I1, and Tm is proportional to the square root of L2. It is expressed by Equation 2.

[0030]

(Equation 2)

By substituting equation (1) into equation (2), the following equation (3) is obtained.

[0032]

(Equation 3)

Therefore, the XCV correction amount is expressed by the following equation (4).

[0034]

(Equation 4)

Further, according to the above equation (4), L3−L4 = C, L
3 + L4 = D, the XCV correction amount becomes
It is expressed by an equation.

[0036]

(Equation 5)

In equation (5), in order to maximize the XCV correction amount, L2 that minimizes the denominator may be obtained. Therefore, to find the change point, the denominator of Expression 5 is represented by Y, L2
Is differentiated by replacing the square root of X with X, respectively. First,
Replacing the denominator of Equation 5 with Y and the square root of L2 with X respectively gives Equation 6 below.

[0038]

(Equation 6)

Next, a value that becomes 0 (zero) is obtained as in the following equation 7 by differentiating the equation (6).

[0040]

(Equation 7)

Further, by substituting L3 + L4 = D into the above equation (7), the following equation (8) is obtained.

[0042]

(Equation 8)

According to equation 8, each coil section 16A-
When the inductance “L2” of 2,16B-2 is equal to the average inductance value of the XCV correction coils 21A, 21B, the XCV correction amount becomes maximum. Generally, the XCV correction coils 21A and 21B are the horizontal deflection coils 16A and 16B.
Since the inductance is smaller than that of the horizontal deflection coils 16A and 16B, by connecting the respective coil intermediate portions T1 and T2 to each other, the inductance "L2" can be reduced, and a large XCV correction amount can be secured. Further, when the same XCV correction amount is secured, XCV
Inductances L3, L of V correction coils 21A, 21B
4 can be reduced.

In the above equation (4), L1 + L2 =
27 μH, L3 = 2.2 μH, L4 = 0.5 μH (L3
+ L4 = 2.7 μH), when the XCV correction amount is calculated to be “1”, the relationship between the XCV correction amount and the inductance ratio of the horizontal deflection coil (L2 / (L1 + L2)) is expressed as shown in FIG. .

In FIG. 6, three straight lines (horizontal lines) E1,
E2 and E3 are the states where the horizontal deflection coils 16A and 16B are not divided (the state where there is no interconnection by the coil middle parts T1 and T2), and the inductances of the XCV correction coils 21A and 21B are doubled, doubled and 1/2 respectively. It shows the XCV correction amount when it is changed to twice. On the other hand, two curves E4
E5 divides the pair of horizontal deflection coils 16A and 16B at coil intermediate portions T1 and T2, respectively, and connects the coil intermediate portions T1 and T2 to each other. In this state, the inductances of the XCV correction coils 21A and 21B are respectively reduced. 1
Coil portions 16A-2, 16B-2
Shows the XCV correction amount when the inductance ratio is changed.

As can be seen from FIG. 6, the horizontal deflection coil 1
When the coils 6A and 16B are divided and connected to each other at the coil intermediate portions T1 and T2, even if the inductance of the XCV correction coils 21A and 21B is halved, the coil portion 16A-
By reducing the inductance ratio of the horizontal deflection coils 16A and 16B to about 20%, the XCV correction amount is equivalent to the case where the horizontal deflection coils 16A and 16B are not divided and the inductance of the XCV correction coils 21A and 21B is made one time. Can be secured.

Since the inductance of the XCV correction coils 21A and 21B is an inductance component that does not contribute to horizontal deflection, the deflection current required for horizontal deflection does not change even if the inductance increases or decreases. Therefore, the horizontal deflection coils 16A, 16
The power required for horizontal deflection changes by increasing or decreasing the total inductance of B and the XCV correction coils 21A and 21B. The horizontal deflection power “Power” is supplied to the horizontal deflection coils 16A and 16B and the XCV correction coil 2
If the total inductance of 1A and 21B is “Lt” and the horizontal deflection current is “Ih”, Power =
Lt × Ih ² . Therefore, when the inductance of the XCV correction coils 21A and 21B is reduced, the deflection power can be reduced accordingly. For this reason, the coil intermediate portion T of the horizontal deflection coils 16A and 16B
By interconnecting 1 and T2, it is possible to reduce the horizontal deflection power while ensuring the same amount of XCV correction as before.

In particular, in a deflection yoke used for a computer display having a high horizontal deflection frequency, by reducing the horizontal deflection power as described above, the heat generated during deflection and the load on the deflection circuit can be reduced. Further, the reduction in the inductance of the entire coil makes it possible to shorten the horizontal retrace period and lower the voltage of the horizontal deflection circuit.

In the above embodiment, the XCV correction coils 21A and 21B are connected in series to the pair of horizontal deflection coils 16A and 16B, respectively. However, the present invention is not limited to this. Not something.

For example, when correcting the misconvergence (hereinafter, XBV) in which the side beams B and R are distorted in a state of being curved in an arc on the horizontal axis of the screen as shown in FIG. Horizontal deflection coil 16A, 1
XBV correction coils 25A and 25B in series with 6B, respectively.
Is adopted. In this case, the XBV correction coils 25A and 25B are respectively wound around cores to which a bias magnetic field is applied by magnets. Also,
One XBV correction coil (for example, XBV correction coil 2
5A) is wound so as to generate a magnetic field in the same direction as the bias magnetic field by the magnet, and the other XBV correction coil (for example, XBV correction coil 25B) is wound so as to generate a magnetic field in the opposite direction to the bias magnetic field. Is done.

Even when such a circuit configuration for XBV correction is employed, a pair of horizontal deflection coils 16A, 1
6B are divided by the coil intermediate portions T1 and T2, respectively, and the coil intermediate portions T1 and T2 are electrically connected to each other, so that the same effect as in the previous embodiment can be obtained. Further, although not shown, the XCV correction coil 2 is connected in series to the pair of horizontal deflection coils 16A and 16B.
The same effect can be obtained by connecting both the 1A and 21B and the XBV correction coils 25A and 25B.

[0052]

As described above, according to the present invention, a pair of horizontal deflection coils are divided at a coil intermediate portion, respectively.
In addition, by electrically connecting the coil intermediate portions to each other, the inductance of the convergence correction coil can be reduced as much as possible, and a larger convergence correction amount can be secured. Thereby, when securing the same convergence correction amount, it is possible to reduce the inductance of the convergence correction coil and increase the deflection efficiency as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing an overall image of a cathode ray tube according to the present invention.

FIG. 2 is a side view including a partially broken surface of the deflection yoke according to the present invention.

FIG. 3 is a diagram showing a circuit configuration of a horizontal deflection system according to the embodiment of the present invention.

FIG. 4 is a diagram illustrating a mounting state of an XCV correction coil.

FIG. 5 is a circuit diagram equivalently converted from the circuit shown in FIG. 3;

FIG. 6 is a correlation diagram between a convergence correction amount (XCV correction amount) and an inductance ratio of a horizontal deflection coil.

FIG. 7 is a diagram showing an occurrence mode of misconvergence (XBV).

FIG. 8 is a circuit diagram showing another application example of the present invention.

FIG. 9 is a diagram showing an occurrence mode of misconvergence (XCV).

FIG. 10 is a diagram showing a circuit configuration of a conventional horizontal deflection system.

[Explanation of symbols]

16A, 16B: horizontal deflection coil, 16A-1, 16A
−2, 16B-1, 16B-2: coil part, 21A, 2
1B: XCV correction coil, 25A, 25B: XBV correction coil, T1, T2: coil intermediate portion

Claims (2)

[Claims] 1. A pair of horizontal deflection coils connected in parallel, and a pair of convergence correction coils connected in series to each of the pair of horizontal deflection coils to vary the balance of current flowing through the pair of horizontal deflection coils. A deflection yoke comprising: a pair of horizontal deflection coils each divided at a coil intermediate portion, and the coil intermediate portions are electrically connected to each other. 2. A pair of horizontal deflection coils connected in parallel, and a pair of convergence correction coils connected in series to each of the pair of horizontal deflection coils to vary the balance of current flowing through the pair of horizontal deflection coils. A display device using a deflection yoke, comprising: a pair of horizontal deflection coils each divided at a coil intermediate portion, and the coil intermediate portions are electrically connected to each other.