JPH04174944A - Deflection device for color cathode-ray tube - Google Patents

Abstract

PURPOSE:To avoid unbalanced deflection so as to prevent the shift of convergence by forming in a pair of saddle type horizontally deflecting coils four circuits including resistors and intermediate terminals. CONSTITUTION:A pair of saddle type horizontally deflecting coils 9H1, 9H2 are provided with respective intermediate terminals 23 and resistors 25 are connected between each terminal 23 and each coil 9H1, 9H2 and between a positive terminal 24a and a negative terminal 24b and four closed circuits including the resistors 25 and the terminals 23 are formed in the pair of coils 9H1, 9H2. With such a constitution, when a vertically deflecting current is made to flow through each of vertically deflecting coils 9V1, 9V2, an induced current flows through the front end portion of each coil 9H1, 9H2 in such a manner as canceling out a magnetic field generated by a deflecting current flowing through the front end portion of each vertically deflecting coil 9V1, 9V2, but the induced current 26 flows through each closed circuit as indicated by the arrows and is attenuated by the resistors 26 constituting each closed circuit. Therefore the magnetic field 27 generated by the current 26 is uniformly deflected and the shift of convergence is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention (Industrial Application Field) The present invention relates to a deflection device for a color cathode ray tube, and more particularly to a deflection device for a color cathode ray tube suitable for an in-line color cathode ray tube.

(Prior Art) In general, an in-line color cathode ray tube has an envelope consisting of a panel (1) and a funnel (2) integrally joined to the panel (1), as shown in FIG. A phosphor screen (3) consisting of a striped three-color phosphor layer that emits blue, green, and red light is formed on the inner surface of the panel (1). A shadow mask (4) in which a large number of electron beam passage holes are formed is arranged. Also, funnel (2
) in the neck (5), a center beam (6G) and a pair of side beams (t3B) passing on the same horizontal plane,
(6R) - 3 electron beams arranged in rows (13B)
, (6G), (8R) electron gun (7)
is arranged, and the three electron beams (6B), (eG), and (SR) emitted from this electron gun (7) are deflected by a magnetic field generated by a deflection device (8) attached to the outside of the funnel (2). By scanning the phosphor screen (3) horizontally and vertically, the phosphor screen (3) is scanned horizontally and vertically.
3) It is formed in a structure that displays a color image thereon.

The deflection device (8) is usually 3 electron beams (6B
) , (6G), (61?) The horizontal deflection coil (9H) that generates a magnetic field that deflects horizontally is a saddle type, and the vertical deflection coil (9■) that generates a magnetic field that deflects vertically is a saddle type. Or a toroidal saddle/
Saddle type or semi-toroidal type deflectors are used.

Such a deflection device (8) is incorporated into a receiver or display device together with a color cathode ray tube, and is driven by a deflection drive circuit built into the receiver or display device. In particular, the vertical deflection coil (9) is driven by a sawtooth vertical deflection current (11) having a screen scanning period and a blanking period as shown in FIG. This vertical deflection current (1
The frequency of 1) is 80H for standard display devices.
z, but recent display devices have a
Some have a frequency of about 100Hz.

By the way, such a vertical deflection current (
11), for example, in a saddle/saddle type deflection device, a pair of saddle type vertical deflection coils (9 m,
(9v2) A current flows in the direction of arrow (12) at the front end (on the panel side of the color cathode ray tube), and this vertical deflection coil (
9m, (9V2) and a pair of upper and lower saddle-type horizontal deflection coils (9H1), (9H2) arranged concentrically inside it through a plastic separator (not shown).
) at the front end of the vertical deflection coil (9m, (9V
An induced current (13) generates a magnetic field that cancels the magnetic field generated by the current flowing through the front end of the tube 2). Furthermore, as shown in FIG. 7(b) in comparison with the vertical deflection current (11) in FIG. occurs strongly.

This induced current (■3) is caused by a pair of upper and lower horizontal deflection coils (9H1) and (9H
2) and 2) are opposite in direction, so they usually cancel each other out.

However, a pair of left and right vertical deflection coils (9Vl), (
If there is a difference in the inductance of the left and right induced currents (9V2), or if the horizontal deflection coils (9HL) and (9H2) are not placed concentrically with the vertical deflection coils (9V1) and (9V2), the left and right induced currents ( 13) become unbalanced and do not cancel each other out, and as shown in Fig. 9, a loop current (15) is generated and flows through a pair of horizontal deflection coils (9H).
1), (9H2) flows. As a result, the three electron beams are transmitted through this pair of horizontal deflection coils (9H1) and (9
Under the influence of the magnetic field generated in H2), the convergence characteristics on the screen deteriorate.

That is, as shown in Fig. 10, the induced current (13) flows through a pair of upper and lower horizontal deflection coils (9H1) and (9H2).
When flowing inside, this pair of horizontal deflection coils (9H1)
, (9H2) is adjacent to the horizontal axis (X-axis) side, a magnetic field (16) shown by the arrow is generated, and this magnetic field (16) causes the pair of side beams (8B), (OR) to
One side beam (blue) (8B) is indicated by the arrow (17b)
) is deflected in one vertical direction (Y-axis direction), and the other side beam (red) (6R) is deflected in ten vertical directions indicated by an arrow (x7r). As a result, as shown in Figure 11,
A convergence shift occurs at the upper end of the screen (18) in which the front side (19B) is at the bottom and the red side (19R) is at the top.

This convergence shift occurs within a range of about one fin at the top of the screen, especially during the retrace period when the vertical deflection current changes rapidly over time.
This is a serious problem that must be solved for high-resolution color display tubes that require convergence deviations of 0.3 to 0.4 mm or less.

(Problem to be Solved by the Invention) As described above, in a color cathode ray tube deflection device, a pair of upper and lower saddle-type horizontal deflection coils is used to cancel the magnetic field generated by the vertical deflection current flowing at the front end of the vertical deflection coil. An induced current is generated at the front end. Normally, this induced current cancels out because the directions are opposite in the pair of upper and lower horizontal deflection coils, but if there is a difference in inductance between the pair of left and right vertical deflection coils, or if the horizontal deflection coil is concentric with the vertical deflection coil. If the horizontal deflection coils are not arranged, the induced current becomes unbalanced and flows through the pair of horizontal deflection coils as a loop current. As a result, the three electron beams, especially the pair of side beams, are deflected by the magnetic field generated by this induced current, causing a convergence shift on the screen. This convergence shift is caused by a strong induced current that occurs during the retrace period, where the vertical deflection current changes rapidly over time.
This appears as a deviation of Jmm, which is a serious problem for high-resolution color display tubes that require a convergence deviation of 0.3 to 0.4 mm or less.

This invention was made to solve the above problem, and the induced current generated at the front ends of a pair of saddle-shaped horizontal deflection coils is unbalanced due to the vertical deflection current flowing through the front ends of the vertical deflection coils. The object of the present invention is to construct a deflection device for color cathode ray tubes that prevents local convergence deviations that occur in color cathode ray tubes.

[Configuration of the Invention (Means for Solving the Problems) At least a pair of saddle-shaped horizontal deflection coils connected in parallel, the pair of saddle-shaped horizontal deflection coils are connected to positive and negative voltage application terminals. In the deflection device for a color cathode ray tube, intermediate terminals were provided for each of the pair of horizontal deflection coils, and resistors were connected between these intermediate terminals and the pressure and negative voltage application terminals, respectively.

(Function) As described above, if intermediate terminals are provided for each of the pair of saddle-type horizontal deflection coils, and resistors are connected between these intermediate terminals and the positive and negative voltage application terminals of the horizontal deflection coils, respectively, Four closed circuits including a resistor and an intermediate terminal are formed in a pair of saddle-shaped horizontal deflection coils, and when a vertical deflection current flows in a conventional vertical deflection coil, an induced current flows in the front end of a pair of saddle-shaped horizontal deflection coils. By changing the direction of the current and attenuating the induced current using a resistor, the unbalanced deflection that the magnetic field generated by the induced current flowing in the front end of the pair of saddle-type horizontal deflection coils conventionally gives to the pair of side beams can be eliminated. By preventing this, it is possible to eliminate convergence shifts that occur locally on the screen.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

FIG. 2 shows a deflection device for a color cathode ray tube, which is an embodiment of the present invention. This deflection device is a saddle/saddle type deflection device, and a pair of saddle type horizontal deflection coils (9
H1) and (9H2) are arranged vertically symmetrically. Further, a pair of saddle-shaped vertical deflection coils (9 m, (9V2)) are arranged symmetrically outside the separator (20) with the vertical axis (Y axis) in between (only (9V2) is shown).

Furthermore, this vertical deflection coil (9Vl), (9V2
) A core (21) is disposed outside the core (21). and the pair of horizontal deflection coils (9H1).

(9H2) Vertical deflection coil (9Vl), (
9V2) are connected in parallel.

Moreover, as shown in FIG. 1, in the deflection device of this example, an intermediate terminal (23) is provided between each horizontal deflection coil (9H1) and (982), and is connected in parallel with each intermediate terminal (23). A pair of horizontal deflection coils (9H1)
.

(Positive terminal (24a) that applies horizontal deflection voltage to 9H2>
and the negative terminal (24b), respectively.
5) is connected to a pair of horizontal deflection coils (9H1),
It has a structure in which four closed circuits including a resistor (25) and an intermediate terminal (23) are formed at (9H2).

By the way, when the deflection device is configured as described above, when the vertical deflection current flows through the vertical deflection coils ('9V1) and (9V2), the horizontal deflection coil is arranged so as to cancel the magnetic field generated by the deflection current flowing through the front end thereof. (9HL).

An induced current (26) flows through the front end of (9H2), but as shown by the arrow, this induced current (26) flows through each closed circuit and is attenuated by the resistor (25) that constitutes each closed circuit. Therefore, as shown in Fig. 3, the direction of the induced current flowing through the horizontal deflection coil of the conventional deflection device changes, and the magnetic field (27) generated by this induced current (2B) side beam (BB),
(8R) is now deflected evenly, and the induced current (26) is applied to the pair of horizontal deflection coils (9H1) and (9H2).
Even if this occurs, it is possible to prevent a convergence shift from occurring.

In the above embodiment, a saddle/saddle type deflection device in which both the horizontal and vertical deflection coils are saddle-shaped has been described, but the present invention is a semi-toroidal deflection device in which the horizontal deflection coil is saddle-shaped and the vertical deflection coil is toroidal. It can also be applied to mold deflection devices.

[Effects of the Invention] An intermediate terminal is provided in each of a pair of saddle-type horizontal deflection coils of a color cathode ray tube deflection device, and a positive and negative voltage application terminal for each of the pair of saddle-type horizontal deflection coils is provided between these intermediate terminals and the pair of saddle-type horizontal deflection coils, respectively. Inserting a resistor prevents the unbalanced deflection that would otherwise be caused to the pair of side beams by the magnetic field generated by the induced current flowing at the front end of the pair of saddle-shaped horizontal deflection coils when a vertical deflection current flows through the vertical deflection coils. As a result, convergence shifts that occur locally on the screen can be eliminated.

[Brief explanation of the drawing]

1 to 3 are detailed explanatory diagrams of the present invention, FIG. 1 is a circuit diagram showing the configuration of a horizontal deflection coil of a deflection device that is an embodiment of the invention, and FIG. 2 is an embodiment of the invention. 3 is a diagram showing the configuration of a saddle/saddle type deflection device, FIG. 3 is a diagram for explaining the action of its horizontal deflection coil, FIGS. 4 to 11 are diagrams for explaining a conventional deflection device, Figure 4 shows the configuration of a color cathode ray tube, Figure 5 is a waveform diagram of the vertical deflection current flowing in the vertical deflection coil of the deflection device, Figure 6 is an explanatory diagram of the induced current flowing in the front end of the horizontal deflection coil, and Figure 7
Figures (a) and (b) are a vertical deflection current waveform diagram and a waveform diagram of the induced current flowing through the horizontal deflection coil corresponding to the vertical deflection current, respectively. Figure 8 explains the induced current flowing through the horizontal deflection coil. 9 is a circuit diagram of the horizontal deflection coil shown to explain the induced current flowing in the horizontal deflection coil, and FIG. 10 is a circuit diagram of the horizontal deflection coil shown to explain the action of the horizontal deflection coil. 11A and 11B are diagrams showing a convergence shift on the screen caused by a conventional deflection device. 9H1, 9H2... A pair of saddle-shaped horizontal deflection coils 9
Vl, 9V2... A pair of saddle-type vertical deflection coils 20
Separator 21 Core 23 Intermediate terminal 24a, 24b Voltage application terminal 25
...Resistance body agent Patent attorney Norihiro Ogo Figure 1 Figure 2 ξ Figure 3 Figure 4 Figure 5 Figure 6 Figure 8

Claims (1)

[Claims] In a color cathode ray tube deflection device comprising at least a pair of saddle-type horizontal deflection coils connected in parallel, the pair of saddle-type horizontal deflection coils are connected to positive and negative voltage application terminals. 1. A deflection device for a color cathode ray tube, characterized in that intermediate terminals are respectively provided, and resistors are connected between these intermediate terminals and the positive and negative voltage application terminals, respectively.