JPH01175149A - Deflection device for in-line type color cathode-ray tube - Google Patents

Abstract

PURPOSE:To obtain good convergence characteristic by connecting a fixed resistor in parallel with one vertical deflecting coil, connecting a pair of serial circuits each consisting of a variable resistor and a diode to the other vertical deflecting coil, and connecting the diodes in opposite directions to each other. CONSTITUTION:During the operation, the deflecting current flows in the path shown by a solid line when the deflection is made to the upper side of a screen, and it flows in the path shown by a dotted line when the deflection is made to the lower side of the screen. To correct the drift of convergence in the vertical direction of the side beam between the upper and lower sections of the screen, the current flowing through a vertical deflecting coil 1a and the current flowing through a vertical deflecting coil 1b must be made different. The correction quantity is determined by the difference of the resistance value between a variable resistor 2a and a fixed resistor 4 on the upper side of the screen and by the difference of the resistance value between a variable resistor 2b and the resistor 4 on the lower side. When the type of diodes 3a and 3b, the variable resistors 2a and 2b, and the resistor 4 are optimized, the unbalance of convergence in the vertical direction of the side beam between the upper and lower sections of the screen can be corrected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Field of Industrial Application) This invention relates to a deflection device for an in-line color picture tube.

(Prior Art) Generally, an in-line color picture tube is equipped with a deflection device. And the in-line color picture tube is
It is structured as follows. That is, the glass bulb consists of a panel, a funnel joined to the panel, and a neck joined to the funnel. A phosphor screen that emits light in B (blue), G (green), and R (red) is formed on the inner surface of the panel, and a shadow mask is provided opposite to this phosphor screen. Furthermore, an in-line electron gun is enclosed within the neck.

On the other hand, the deflection device consists of a pair of saddle-shaped horizontal deflection coils and a pair of saddle-shaped vertical deflection coils, and is attached to the neck of the color picture tube.

In this deflection device, a pair of vertical deflection coils generates a pincushion-shaped magnetic field to correct the convergence shift. However, when correcting the vertical convergence shift of the side beams at the top and bottom of the screen, the circuit configuration of the conventional deflection device is as shown in Figure 2.

That is, resistors 5a and 5b are connected in parallel to each coil of the pair of vertical deflection coils la and lb, and a differential resistor 6 is connected between the pair of vertical deflection coils la and lb and the pair of resistors 5a and 5b. By operating this differential resistor 6, the vertical deflection coil la.

The deflection current flowing through 1b is different for each coil.

The vertical deflection coils la and lb are provided in an in-line type electron gun 7B, as shown in FIG.

They are arranged in a pair in the arrangement direction of 7G and 7H, and generate a vertical deflection magnetic field 8. And vertical deflection coils 1a, 1b
If the deflection currents flowing through the respective side beams are different, the left-right symmetry of the vertical deflection magnetic field 9 will be disrupted, as shown in FIG. Corrects the vertical convergence of the side beams.

(Problem to be solved by the invention) However, in the conventional deflection device as described above, the fourth
In the state of the differential resistor 6 when generating the vertical deflection magnetic field 9 shown in the figure, the distribution of the vertical magnetic field deflected toward the bottom of the screen is as follows:
As shown in FIG. 5, the distribution shapes of the magnetic fields are the same and only the directions of the magnetic fields are opposite.

Therefore, on the upper side of the screen as shown in Figure 6, the B beam 10 is on top and the R beam 11 is on the bottom, and even on the bottom side of the screen, the B beam 10 is on top or vice versa, or there is a difference in the amount of convergence shift between the top and bottom of the screen. It is difficult to correct a pattern where there is a difference.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an in-line deflection device for a color picture tube that can correct unbalanced convergence shifts between the top and bottom of the screen.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides an in-line color picture tube deflection device having a pair of saddle-type horizontal deflection coils and a pair of saddle-type vertical deflection coils. A fixed resistor is connected in parallel to one side of the vertical deflection coil, and a series circuit of a variable resistor and a diode is connected in parallel to the other side.
The in-line color picture tube deflection device is characterized in that the pair of diodes are connected such that their polarities are in opposite directions.

(Function) According to the present invention, the distribution shape of the vertical magnetic field for deflecting the screen vertically can be changed independently. As a result, it is possible to independently correct the vertical convergence deviation of the unbalanced side beams at the top and bottom of the screen.

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

The circuit configuration near a pair of saddle-type vertical deflection coils in the in-line color picture tube deflection device of the present invention is shown in Figure 1, and the same parts as in the conventional example (Figure 2) are given the same reference numerals. do.

That is, a fixed resistor 4 is connected in parallel to one coil 1b of a pair of saddle-type vertical deflection coils 1b connected in series, and a series circuit of a variable resistor 2a and a diode 3a is connected in parallel to the other coil 1b. and variable resistor 2b and diode 3
b is connected to the series circuit, and the diodes 3a, 3b
The polarities of each are connected in opposite directions.

Further, the connection point between these series circuits and the fixed resistor 4 is connected to the connection point between the vertical deflection coils 1a and 1b.

During operation, the deflection current when deflecting to the upper side of the screen follows the path shown by the solid line, and the deflection current when deflecting to the lower side of the screen follows the path shown by the dotted line.

Now, in order to correct the shift in the vertical convergence of the side beams at the top and bottom of the screen, the vertical deflection coil 1a
The current flowing through the vertical deflection coil 1b must be different from the current flowing through the vertical deflection coil 1b.

That is, the correction amount is determined by the difference in resistance value between the variable resistor 2a and the fixed resistor 4 on the upper side of the screen, and by the difference in resistance value between the variable resistor 2b and the fixed resistor 4 on the lower side of the screen.

In this way, by optimally selecting the types of diodes 3a s 3b, the variable resistors 2a% 2b, and the fixed resistor 4, it is possible to correct the unbalance of the vertical convergence shift of the side beams at the top and bottom of the screen. I can do it.

[Effects of the Invention] According to the present invention, the current flowing through each of the pair of saddle-type vertical deflection coils is made different to correct the shift in the vertical convergence of the side beams at the top and bottom of the screen. This is a pair of series circuits connected to each other, and the polarities of the diodes are opposite to each other, so the variable resistance that acts on the top and bottom of the screen is different. In other words, the distribution shape of the vertical deflection magnetic field for deflecting the screen vertically can be changed independently.

Therefore, it is possible to independently correct the unbalanced convergence shift in the vertical direction of the side beams occurring at the top and bottom of the screen, and as a result, it is possible to provide an in-line color picture tube deflection device having good convergence characteristics.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing the main parts of an in-line color picture tube deflection device according to an embodiment of the present invention, and FIG. 2 is a circuit diagram showing the main parts of a conventional in-line color picture tube deflection device. Figure 3 is a cross-sectional view showing the relationship between the electron beam and the deflection magnetic field, Figure 4 is a cross-sectional view showing the principle of correcting the vertical convergence deviation of the side beam at the top of the screen, and Figure 5 is the deflection towards the bottom of the screen. FIG. 6 is a cross-sectional view showing the shape of the magnetic field when this happens, and FIG. 6 is a plan view showing the unbalanced convergence shift of the side beams at the top and bottom of the screen. la, lb...Vertical deflection coil, 2a12b...variable resistor, 3a, 3b...diode, 4...fixed resistor. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] In an in-line color picture tube deflection device having a pair of saddle-type horizontal deflection coils and a pair of saddle-type vertical deflection coils, a fixed resistor is connected in parallel to one of the pair of saddle-type vertical deflection coils. and a pair of series circuits of a variable resistor and a diode are connected in parallel to the other, and the polarities of the pair of diodes are connected in opposite directions to each other. .