JPH07212773A - Deflection yoke for color cathode ray tube - Google Patents

Abstract

PURPOSE:To correct the deflection state of a G beam at an upper part of a screen at the start of electronic beam scanning by connecting a series circuit comprising a 2nd frame correction coil and an anti-parallel connection diode pair in parallel with a series circuit consisting of a resistor and an inductor of a vertical deflection circuit. CONSTITUTION:An inductor L being an impedance element is connected in series with a resistor R in a vertical deflection circuit for a deflection yoke 3. A series circuit comprising a 2nd frame correction coil L2 and anti-parallel connection didoes D1, D2 is connected in parallel with the series circuit comprising the resistor R and the inductor L. The impedance of the inductor L is preferably selected to be nearly equal to that of the coil L2. A deflection current hardly flows to the coil L having a high impedance at the start of electronic beam scanning and then also to the resistor R because of the series connection of the inductor L to the resistor R, resulting that the same degree of the deflection current flows to the resistor R and the coil L2 and then a G beam at the upper part of the screen is not directed outward from R, B beams and then the direction of the G beam is in matching with the direction of the R, B beams.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deflection yoke for a color cathode ray tube, and more specifically, it is mounted on a color cathode ray tube having an in-line type electron gun built therein and deflects an electron beam from the in-line type electron gun vertically and horizontally. The present invention relates to a deflection yoke for a color cathode ray tube.

[0002]

2. Description of the Related Art A color cathode ray tube 2 having a built-in in-line type electron gun 1 emits an electron beam emitted from the in-line type electron gun 1 as shown in FIG. A deflection yoke 3 for deflecting in the orthogonal direction, that is, in the vertical direction and the horizontal direction is provided.

The deflection yoke 3 is formed by winding a vertical deflection coil for vertically deflecting an electron beam [RGB beam] from the in-line type electron gun 1 and a horizontal deflection coil for horizontally deflecting the electron beam. The structure is general. Here, regarding the vertical deflection by the deflection yoke 3,
As shown in FIG. 4, in the upper and lower end positions of the screen m of the color cathode ray tube 2, the R beam and the B beam of the electron beams from the in-line type electron gun 1 are in the normal positions, but the G beam is the RB. It has a narrow characteristic of being inside the normal position of the beam.

In order to correct the narrow characteristic of the G beam, the deflection yoke 3 is provided with coma correction coils L ₁ and L ₂ which are vertically positioned with respect to the inline type electron gun 1 as shown in FIG. [See FIG. 3]. The illustrated coma correction coils L ₁ and L ₂ are referred to as a two-stage four-pole coma coil system, and a first coma correction coil L ₁ and a second coma correction coil L ₂ which will be described later are wound in double. Has been done.

As described above, the vertical deflection circuit of the deflection yoke 3 which is involved in the vertical deflection of the electron beam and which has the coma correction coils L ₁ and L ₂ has a vertical deflection coil L _{V as} shown in FIG.
And a first coma correction coil L ₁ and a resistance R are connected in series, and a series circuit of a _second coma correction coil L ₂ and an antiparallel diode pair D ₁ and D ₂ is connected in parallel to the resistance R. It is composed of

In this vertical deflection circuit, the first frame correction
IL L₁Causes the upper half of screen m to face upward and
In the half, the deflection of the G beam, which is directed downward, is smaller than that of the RB beam.
Correcting the narrow characteristics of the G beam by making it larger
I am trying to do it. Also, this first coma correction coil
L₁Only the top or bottom of the screen m as shown in FIG.
G beam from RB beam at intermediate position a from the center to
Too biased outward. Therefore, the second frame correction
IL L₂And anti-parallel diode pair D₁, D₂Series circuit with
Provided, the electron beam is a part of the upper quadrant and lower quadrant of the screen m
When scanning a part (hatched part in Fig. 7), the reverse parallel
Diode pair D₁, D₂And the second coma correction coil L₂Directly
Column circuit, first coma correction coil L₁And vertical deflection coil
L_VThe vertical deflection current flows through the
Part other than] when scanning the anti-parallel diode pair D
₁, D₂Is turned off, the resistance R and the first frame correction coil
Le L ₁And vertical deflection coil L_VVertical deflection current flows through
And try to correct the excessive deflection of the G beam.
It

[0007]

By the way, when the electron beam is deflected by the deflection yoke 3 to start scanning from the upper end of the screen m, in the vertical deflection circuit, the impedance of the second coma correction coil L ₂ is high. , The vertical deflection current hardly flows through the second coma correction coil L _2, and the vertical deflection current mainly flows through the resistor R. If the vertical deflection current easily flows through the resistor R at the beginning of scanning as described above, the G beam is directed to the outside of the RB beam at the upper end of the screen m as shown in FIG. Becomes difficult to match.

Further, in the color cathode ray tube 2 comprises a frame correction coils L _1, L _2, the frame correction coils L _1, L ₂ on the characteristic, the direction of arrangement of the line type electron gun 1 in the upper and lower ends of the screen m On the other hand, a phenomenon called cross miss convergence occurs in which the RB beam tilts. Therefore, there is also a problem that a means for correcting the cross miss convergence must be provided separately from the vertical deflection circuit.

Therefore, the present invention has been proposed in view of the above problems, and an object thereof is to correct the deflection state of the G beam at the upper end of the screen by a simple means at the beginning of the scanning of the electron beam. Another object of the present invention is to provide a deflection yoke for a color cathode ray tube, which is equipped with a vertical deflection circuit that can be used.

[0010]

As a technical means for achieving the above object, the present invention is assembled in a color cathode ray tube having an in-line type electron gun built therein, and is orthogonal to the beam arrangement direction of the in-line type electron gun. A vertical deflection coil for deflecting the electron beam in the direction and a coma correction coil for correcting the electron beam vertically deflected are provided, and the vertical deflection coil, the first coma correction coil, and the resistor are connected in series. In a vertical deflection circuit of a deflection yoke in which a series circuit of a second coma correction coil and an antiparallel diode pair is connected in parallel to a resistance, an impedance element is connected in series to the resistance, and a series circuit of the resistance and the impedance element is connected. In addition, a series circuit of a second coma correction coil and an anti-parallel diode pair is connected in parallel.

The impedance element is preferably an inductor, and more preferably has an impedance substantially equal to that of the second coma correction coil.

[0012]

In the deflection cathode for a color cathode ray tube according to the present invention, the impedance element is inserted and connected in series with the resistor, so that the impedance element prevents the deflection current from flowing into the resistor at the start of scanning of the electron beam and is connected in parallel. The same amount of deflection current is allowed to flow through the resistor and the second coma correction coil. As a result, the G beam does not go to the outside of the RB beam at the top of the screen
It is possible to match the B beam.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a deflection yoke for a color cathode ray tube according to the present invention will be described with reference to FIGS. The same parts as those in FIGS. 3 to 8 are designated by the same reference numerals, and a duplicate description will be omitted.

A feature of the present invention is that in the vertical deflection circuit of the deflection yoke 3 as shown in FIG. 1, an inductor L, which is an impedance element, is inserted and connected in series with a resistor R, and the resistor R and the inductor L are connected in series. In addition, the series circuit of the second coma correction coil L ₂ and the anti-parallel diode pair D ₁ and D ₂ is connected in parallel. In addition, this inductor L is
It is desirable to have an impedance that is substantially the same as that of the second coma correction coil L ₂ .

In the vertical deflection circuit of the present invention, since the inductor R is inserted and connected to the resistor R in series, it is difficult for the deflection current to flow in the _second coma correction coil L ₂ having a high impedance at the start of scanning the electron beam. Similarly, since the impedance of the inductor L is high, it becomes difficult for the deflection current to flow through the resistor R. As a result, the same degree of deflection current will flow through the resistor R and the second coma correction coil L ₂ connected in parallel, which causes the G beam to be the RB beam at the upper end of the screen m as shown in FIG. It is possible to match the G beam with the RB beam without facing the outside.

Further, in the color cathode ray tube 2 provided with the coma correction coils L ₁ and L ₂ as in the present invention, due to the characteristics of the coma correction coils L ₁ and L ₂ , the in-line type electron gun is provided at the upper and lower ends of the screen m. Although a phenomenon called cross-misconvergence in which the RB beam is inclined with respect to the arrangement direction of 1 has occurred, the inductor L in the present invention can also be used as a means for correcting this cross-miss convergence.

[0017]

According to the deflection yoke for a color cathode ray tube according to the present invention, an impedance element is connected in series to the resistance of the vertical deflection circuit, and the series circuit of the resistance and the impedance element is connected to the reverse of the second coma correction coil. By connecting the series circuit with the parallel diode pair in parallel, the deflection state of the G beam at the upper edge of the screen can be corrected at the beginning of scanning the electron beam, and the cross-miss convergence due to the characteristics of the coma correction coil is improved. It can be done and its practical value is great.

[Brief description of drawings]

FIG. 1 is a vertical deflection circuit diagram showing an embodiment of a deflection yoke for a color cathode ray tube according to the present invention.

FIG. 2 is a front view of a screen showing a G beam correction state by the vertical deflection circuit of the present invention.

FIG. 3 is a side view showing a deflection yoke attached to a color cathode ray tube.

FIG. 4 is a front view of a screen showing narrow characteristics of a G beam in a color cathode ray tube.

FIG. 5 is a front view showing a coma correction coil included in a deflection yoke.

FIG. 6 is a vertical deflection circuit diagram showing a conventional deflection yoke for a color cathode ray tube.

FIG. 7 is a front view of a screen showing a split state for correcting G beam deflection by a vertical deflection circuit.

FIG. 8 is a front view of a screen showing an undesired deflection state of a G beam and a cross miss convergence of an RB beam by a conventional vertical deflection circuit.

[Explanation of symbols]

1 in-line type electron gun 2 color cathode ray tube 3 deflection yoke R resistance L impedance element [inductor] L _V vertical deflection coil L ₁ first coma correction coil L ₂ second coma correction coil D ₁ , D ₂ anti-parallel diode pair

Claims (3)

[Claims] 1. A vertical deflection coil which is assembled to a color cathode ray tube having a built-in in-line type electron gun and deflects the electron beam in a direction orthogonal to the beam arrangement direction of the in-line type electron gun, and the vertically deflected electron beam. A vertical deflection coil, a first frame correction coil and a resistor are connected in series, and a serial circuit of a second frame correction coil and an anti-parallel diode pair is connected in parallel to the resistor. In the vertical deflection circuit of the connected deflection yoke, an impedance element is connected in series to the resistance, and a series circuit of the second coma correction coil and the antiparallel diode pair is connected in parallel to the series circuit of the resistance and the impedance element. A deflection yoke for a color cathode ray tube characterized in that 2. A deflection yoke for a color cathode ray tube, wherein the impedance element according to claim 1 is an inductor. 3. A deflection yoke for a color cathode ray tube, wherein the inductor according to claim 2 has an impedance substantially equal to that of the second coma correction coil.