JPH05328371A - Convergence correcting device - Google Patents

Abstract

PURPOSE:To apply a proper misconvergence correcting variable also to a large CRT with wide angle deflection by connecting two diodes which are connected in parallel so as to be mutually reversed at their polarity to both the ends of a vertical auxiliary coil in parallel. CONSTITUTION:Two diodes 31, 32 which are connected in parallel so as to be mutually reversed at their polarity are connected to the vertical auxiliary coil 23 in parallel. When a vertical deflecting current is increased and a current flowing between both the ends of the coil 23 reaches the forward voltage of the diode 31 or 32, the diode 31 or 32 is turned on and a part of the vertical deflecting current is by-passed to the diode 31 or 32, so that the current flowing through the coil 23 is not increased. Since the current of the coil 23 is not increased even when the vertical deflecting current is increased, a misconvergence correcting variable due to the unbalance of a horizontal deflecting current does not exceed a certain value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke convergence correcting device used in a television receiver.

[0002]

2. Description of the Related Art In recent years, television receivers have been moving toward a large screen and wide-angle deflection, and correction of misconvergence has become an important issue.

Generally, as a convergence correction device, a circuit for modulating the inductance of a horizontal deflection coil with a vertical deflection current as shown in FIG. 4 is used. Figure 4
In FIG. 1, reference numeral 1 is a deflection yoke, which is composed of horizontal deflection coils 11 and 12 connected in parallel and vertical deflection coils 13 and 14 connected in series. A convergence correction device 2 includes a first horizontal auxiliary coil 21 connected in series to the first horizontal deflection coil 11 and a second horizontal auxiliary coil 22 connected in series to the second horizontal deflection coil 12. A vertical auxiliary coil 23 connected in series to the vertical deflection coils 13 and 14 and permanent magnets 24 and 25 (FIG. 5). As shown in FIG. 5, the cores of the first horizontal auxiliary coil 21, the second horizontal auxiliary coil 22, and the vertical auxiliary coil 23 are ferrite drum cores.
Each of the horizontal auxiliary coil 21 and the second horizontal auxiliary coil 22 is wound on two ferrite drum cores, and the two cores of the first horizontal auxiliary coil 21 are a permanent magnet 24 and a vertical auxiliary coil 23. The two cores of the second horizontal auxiliary coil 22 are sandwiched between the vertical auxiliary coil 23 and the permanent magnet 25. The windings of the first horizontal auxiliary coil 21 and the second horizontal auxiliary coil 22 are connected so that the inductance of each of the two coils on each of the two cores becomes the sum. The core of the first horizontal auxiliary coil 21 and the core of the second horizontal auxiliary coil 22 are both cores saturated with a magnetic flux slightly larger than the sum of the magnetic flux of the horizontal deflection current and the magnetic flux of the permanent magnets 24 or 25. I'm using it. The magnetic flux of the vertical auxiliary coil 23 is the first horizontal auxiliary coil 21 and the second auxiliary coil 23.
The core of the horizontal auxiliary coil 22 is penetrated to differentially change the inductance of the first horizontal auxiliary coil 21 and the inductance of the second horizontal auxiliary coil 22. Therefore, the current I ₁₁ flowing through the first horizontal deflection coil ₁₁ and the second current I ₁₁
The current I ₁₂ flowing through the horizontal deflection coil 12 changes differentially according to the magnitude of the vertical deflection current.

Next, the point that the inductances of the two horizontal auxiliary coils 21 and 22 change differentially will be described. In FIG. 5, upper and lower coils 211 and 212 of the first horizontal auxiliary coil 21 and the second horizontal auxiliary coil 22.
The upper and lower coils 221 and 222 have the same shape,
Due to the number of turns, the magnetic flux penetrating through the core by these coils is of the same magnitude. Let that value be Φ2.

Further, the magnetic flux penetrating through the upper and lower cores of the first and second horizontal auxiliary coils 21 and 22 of the permanent magnets 24 and 25 by the vertical auxiliary coil 23 is Φv. Permanent magnet 2
4 and 25 have the same shape and the same magnetic force. If the magnetic flux penetrating through the upper and lower cores of the first and second horizontal auxiliary coils 21 and 22 by these magnets is Φm, the core of the upper coil 211 is Penetrating magnetic flux Φ211 = Φ
2 + Φm + Φv Magnetic flux Φ212 = Φ that penetrates the core of the lower coil 212
2-Φm−Φv The core of the horizontal auxiliary coil 21 uses a core that is saturated with a magnetic flux (Φ2 + Φm + Φα) slightly larger than the sum of the magnetic flux of the horizontal deflection current and the magnetic flux of the permanent magnet 24. Magnetic flux Φ that penetrates the core of the coil 211
211 does not increase more than (Φ2 + Φm + Φα) and becomes a constant value (Φ2 + Φm + Φα). Assuming that the inductance of the upper coil is L211 and the inductance of the lower coil is L212, the inductance value of the coil is proportional to the number of magnetic fluxes penetrating through it, so if the proportionality constant is k, then L211 = kΦ211 = k (Φ2 + Φm + Φα) L212 = kΦ212 = k (Φ2-Φm−Φα) Therefore, the inductance L21 of the first horizontal auxiliary coil 21 is L21 = L211 + L212 = k (2Φ2 + Φα−Φ
v) Similarly, L221 = kΦ221 = k (Φ2 + Φm−Φv) L222 = kΦ222 = k (Φ2-Φm + Φv) Since they do not reach the saturation magnetic flux, L22 = L221 + L222 = 2kΦ2 (constant) vertical auxiliary coil 23 In the period in which the vertical deflection current flowing in the vertical direction has the opposite polarity and the magnetic flux Φv in the vertical auxiliary coil 23 increases in the direction opposite to the direction shown in FIG. Φ2-Φm-Φv, the upper core of the second horizontal auxiliary coil 22 in FIG. 5 is saturated, and above the saturation point L21 = 2kΦ2 (constant) L22 = k (2Φ2 + Φα-Φv) From the above, two horizontal The inductances of the auxiliary coils 21 and 22 change according to the vertical deflection current, and the changes work differentially with each other. I understand. This pattern is shown in FIG. Therefore, the deflection current flowing through the two horizontal deflection coils 11 and 12 changes according to the vertical deflection current,
If the current of the horizontal deflection coil 11 increases, the current of the second horizontal deflection coil 12 decreases, and conversely, if the current of the first horizontal deflection coil 11 decreases, the current of the second horizontal deflection coil 12 increases. To do. By this differential operation, the cathode ray tube (C
The electron beam in (RT) is displaced in the direction shown in FIG.

At the center of the screen, the vertical deflection current is 0,
Since the magnetic flux of the direct auxiliary coil 23 is 0, the first horizontal auxiliary coil is
Inductor of auxiliary coil 21 and second horizontal auxiliary coil 22
Both coils have the same inductor without changing the
Value of the horizontal deflection coils 11, 12
Deflection current I₁₁And I₁₂Are the same size. screen
Vertical deflection coil 1 at a position above or below the center of
Since the current is flowing in 3 and 14, the same current is applied to the vertical assistance.
The magnetic flux of the vertical auxiliary coil 23 flows to the coil 23
Cores of the horizontal auxiliary coil 21 and the second horizontal auxiliary coil 22
Through the inductor of the first horizontal auxiliary coil 21.
Differential inductance of the second horizontal auxiliary coil 22
Deflection, and the deflection flowing in the horizontal deflection coils 11 and 12
Current I₁₁, I ₁₂The difference between the
Creates a valence pattern. Large vertical deflection current
The difference between the currents flowing in the two horizontal deflection coils in proportion to the magnitude
Becomes larger and the amount of misconvergence correction becomes larger.
It

[0007]

However, in such a conventional convergence correction device, the S-shaped misconvergence is not large in the case of a medium-sized or small-sized CRT even with wide-angle deflection, so that the misconvergence is caused by the magnetic field of the deflection coil. Although it can be reduced, the amount of misconvergence correction is uniquely determined in proportion to the vertical deflection current, and in the case of a large CRT with wide-angle deflection, the amount of misconvergence correction becomes excessive at the top and bottom of the screen, which is correct. I couldn't correct it.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a convergence correction device which gives a preferable amount of misconvergence correction to a large-sized wide-angle deflection CRT.

[0009]

In order to achieve the above-mentioned object, the present invention provides a vertical auxiliary coil of a conventional convergence correction apparatus in parallel with two diodes connected in parallel with opposite polarities so that an auxiliary The correction current flowing through the coil is controlled.

[0010]

According to the present invention, the correction current flowing in the auxiliary coil is controlled by the above-mentioned structure, so that the large-sized wide-angle deflection CRT can be obtained.
Also for this, it is possible to provide a preferable misconvergence correction amount.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
Will be described with reference to. FIG. 1 shows the connection between the deflection coil and the convergence correction device of the present invention, as in FIG. 4 of the conventional example. FIG. 2 is a structural diagram and a circuit diagram of a convergence correction device according to an embodiment of the present invention. The vertical auxiliary coil 23 of the conventional example shown in FIG.
The individual diodes 31 and 32 are connected. The components and connections other than these newly added two diodes 31 and 32 are exactly the same as those in the conventional example, and therefore the description thereof is omitted.

As the vertical deflection current increases, the vertical auxiliary coil 2
When the voltage V1 across 3 reaches the forward voltage Vd of the diode 31 or 32, the diode is turned on, the vertical deflection current is partially bypassed by the diode, and the current of the vertical auxiliary coil 23 does not increase. This pattern is shown in FIG. 3 as a waveform of the terminal voltage of the vertical auxiliary coil 23 by a solid line, and for comparison, the waveform of the terminal voltage of the conventional example is shown by a broken line in the same figure.

Therefore, the correction amount of misconvergence due to the imbalance of the horizontal deflection current becomes irrelevant to the vertical deflection current at this point. That is, the correction amount no longer increases at the top or bottom of the screen. The maximum correction amount can be adjusted by the resistance value of the vertical auxiliary coil 23 and the forward voltage value Vd of the diodes 31 and 32.

[0014]

As is apparent from the above description of the embodiments, according to the present invention, two diodes connected in opposite polarities to each other are connected in parallel to both ends of the vertical auxiliary coil. After the terminal voltage exceeds the forward voltage of the diode, the current of the vertical auxiliary coil does not increase even if the vertical deflection current increases, so the misconvergence correction amount due to the unbalance of the horizontal deflection current increases beyond a certain value. Without doing so, it is possible to provide a preferred convergence correction device for a large wide-angle deflection CRT.

[Brief description of drawings]

FIG. 1 is a diagram showing a connection between a deflection coil and a convergence correction device according to an embodiment of the present invention.

FIG. 2 is the same structure and circuit diagram of the convergence correction device.

FIG. 3 is a waveform diagram of the terminal voltage of the vertical auxiliary coil.

FIG. 4 is a diagram showing a connection between a conventional deflection coil and a convergence correction device.

FIG. 5 is a structure and circuit diagram of the convergence correction device.

FIG. 6 is a diagram showing that two horizontal auxiliary coils are differentially increased or decreased by a vertical deflection current.

FIG. 7 is a diagram showing a moving direction of a beam by the convergence correction device.

[Explanation of symbols]

 11 1st horizontal deflection coil 12 2nd horizontal deflection coil 13, 14 Vertical deflection coil 21 1st horizontal auxiliary coil 22 2nd horizontal auxiliary coil 23 Vertical auxiliary coil 31, 32 Diode

Claims (1)

[Claims] 1. Two horizontal auxiliary coils serially connected to each of the two horizontal deflection coils, one vertical auxiliary coil serially connected to the vertical deflection coil, and the vertical auxiliary coil in parallel. 2 connected in parallel with opposite polarities
The two horizontal auxiliary coils are magnetically coupled to the vertical auxiliary coils so that the inductances of the two horizontal auxiliary coils are differentially increased or decreased by a vertical deflection current flowing through the vertical auxiliary coils. Convergence correction device that is physically coupled.