JPH033034Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a convergence correction circuit, and more particularly, to a circuit for correcting misconvergence of a center beam due to coma aberration.

2. Description of the Related Art Generally, in a color television receiver or color display device equipped with an in-line color cathode ray tube and a cell convergence type deflection yoke, the horizontal deflection magnetic field of the deflection yoke has a pink-tension type magnetic field distribution, and the vertical deflection magnetic field has a barrel-type magnetic field distribution. It is well known that this causes center beam misconvergence (hereinafter referred to as coma error) due to coma aberration, as shown in FIG.

As a means to correct the above frame error,
Conventionally, as shown in FIG. 6, a set of magnetic pieces 1a and 1b is provided in the electron gun to shield or enhance the three beams R, G, and B as needed, or As shown in FIG. 7A, there is one in which one or more sets of correction coils 2a and 2b that generate a hexapole magnetic field or a quadrupole magnetic field are arranged near the electron gun.

Problems to be Solved by the Invention In the device shown in Figure 6, due to variations in the dimensions of the magnetic pieces 1a and 1b and the magnetic field distribution of the deflection yoke,
On the other hand, the device shown in FIG. 7A generally has the circuit configuration shown in FIG.
Each variation in the number of windings causes variations in the amount of coma error correction, and each of them has the problem that it is difficult to optimally correct the coma error.

SUMMARY OF THE INVENTION An object of the present invention is to provide a convergence correction circuit that can arbitrarily set the coma error correction amount and correct misconvergence of horizontal lines of side beams on the upper and lower sides of the screen.

Means for Solving the Problems In FIG. 1, the variable resistor 13 is an example of a means for arbitrarily varying the coma error correction amount. This variable resistor is connected in parallel to the correction coil, and the other end of its movable piece is connected to the connection point of the correction coil.

Function The variable resistor 13 activates the coma error correction coil 2.
The ratio of the vertical deflection currents flowing through a and 2b can be arbitrarily varied.

Embodiment FIG. 1 shows a basic circuit diagram of the circuit of the present invention, in which the same parts as in FIG. 7B are given the same numbers. In the figure, a variable resistor 13 is connected in parallel to both ends of the correction coils 2a and 2b connected in series. 11 and 12 are vertical deflection current input terminals.

The vertical deflection current that has entered the terminals 11 and 12 branches and flows through the correction coils 2a and 2b, the series connection of the vertical deflection coil 3, and the variable resistor 13. At this time, by varying the movable piece 13a of the variable resistor 13, the magnitude of the vertical deflection current flowing through the correction coils 2a and 2b can be arbitrarily varied, thereby setting the amount of coma error correction to the optimum value. obtain.

FIG. 2A shows a circuit diagram of an example of the present invention, in which the same parts as in FIG. 7B and FIG. 1 are given the same numbers. In the figure, 14 is a variable resistor, and its movable piece 14a is connected to a connection point 15 between the correction coils 2a and 2b.

The vertical deflection current that has entered the terminals 11 and 12 flows through the correction coils 2a and 2b, the vertical deflection coil 3, and the variable resistor 13. Movable piece 14a of variable resistor 14
is connected to the connection point 15 between the correction coils 2a and 2b, so the magnitude of the vertical deflection current flowing through the correction coils 2a and 2b, respectively, can be arbitrarily varied in opposite directions at the same rate by the variable resistor 14. In other words, the ratio of the vertical deflection currents flowing in each can be arbitrarily varied.

In this way, the magnitude of the vertical deflection current flowing through the correction coils 2a and 2b can be varied in opposite directions at the same rate, so that the total vertical deflection current flowing through the correction coils 2a and 2b can be adjusted as shown in the first diagram. cannot be varied, but it is possible to vary the balance of the vertical deflection currents flowing in each.

For example, if the current flowing through the correction coil 2a is made larger than the current flowing through the correction coil 2b, the magnetic field acting on the beam R will be larger than that on the beam B, as shown in FIG. 2B. As shown in FIG. 3A, the horizontal line of the side beam R on the upper and lower sides of the screen changes to be outside of the horizontal line of the side beam B.

On the other hand, if the current flowing through the correction coil 2b is operated to be larger than the current flowing through the correction coil 2a, the magnetic field acting on the beam B becomes larger than that on the beam R, contrary to the above. As shown in FIG. 3B, the horizontal line of the side beam B on the upper and lower sides of the screen changes so that it is on the outside of the horizontal line of the side beam R.

As described above, although the amount of coma error correction cannot be varied in this embodiment, by adjusting the variable resistor 14, it is possible to correct the misconvergence of the horizontal lines of the side beams R and B on the upper and lower sides of the screen.

In addition, as shown in FIG. 4, the movable pieces 16a, 17
By using the variable resistors 16 and 17 provided with a, it is possible to set the coma error correction amount to an optimum value, and also correct misconvergence of the horizontal lines of the side beams on the upper and lower sides of the screen.

Further, in each of the above embodiments, the coma error correction coils 2a and 2b are connected in series with the vertical deflection coil 3, but the invention is not limited to this, and the coma error correction coils 2a and 2b are connected in parallel with the vertical deflection coil 3. You can.

Further, although each of the above embodiments deals with a vertical coma error, the same concept can be applied to a horizontal coma error.

Effects of the invention The circuit of this invention connects a variable resistor in parallel to the coma error correction coil, and connects the other end of the movable piece to the connection point of the correction coil, thereby reducing the misconvergence of the horizontal lines of the side beams on the upper and lower sides of the screen. The impedance of the deflection coil can be corrected, significantly improving the image quality of color television receivers and color display devices, and by setting the resistance value of the variable resistor arbitrarily to widen the variable range of the amount of coma error correction, the impedance of the deflection coil can be improved. Even if the number of turns of the correction coil is changed, the optimum amount of correction can be obtained without changing the number of turns of the correction coil, and the correction coil can be standardized.

[Brief explanation of drawings]

Figure 1 is a basic circuit diagram of the circuit of the present invention, Figure 2 is a circuit diagram of an example of the circuit of the present invention and a diagram for explaining the magnitude of the magnetic field acting on the beam, and Figure 3 is a side beam on the upper and lower sides of the screen. Figure 4 is a circuit diagram of another embodiment of the circuit of the present invention, Figure 5 is a pattern of misconvergence due to comatic aberration, and Figure 6 is a conventional correction means. FIG. 7 is a diagram and a circuit diagram for explaining the magnitude of the magnetic field acting on the beam in another example of the conventional correction means. 2a, 2b...column error correction coil, 3...
... Vertical deflection coil, 11, 12 ... Vertical deflection current input terminal, 13, 14, 16 ... Variable resistor, 13
a, 14a, 16a, 16b...movable piece, 15...
...connection point.

Claims (1)

[Scope of Claim for Utility Model Registration] A convergence correction circuit in which a deflection coil and two series-connected correction coils for correcting misconvergence of a center beam due to coma aberration are connected between deflection current input terminals, A convergence correction circuit comprising a variable resistor connected in parallel to a correction coil, and the other end of the movable piece of the variable resistor connected to a connection point between the two correction coils.