JPH0355747A - Deflection yoke - Google Patents

Abstract

PURPOSE:To easily cope with a change even if trilemma is changed by providing a pair of auxiliary coils disposed in opposite positions on the rear part X-axis of main horizontal deflection coils and selectively dividing a part of the current running to the horizontal deflection coils. CONSTITUTION:In opposite positions on the rear part X-axis of main horizontal deflection coils 5, 6, a pair of auxiliary coils 2, 3 are provided, and a part of the current running into the coils 5, 6 is selectively divided by the coils 2a, 3a of the auxiliary coils. A current IC divided by a variable inductance 4 is sent to the coils 2a, 3a, whereby a magnetic flux PHI0 is formed. When the horizontal deflection magnetic flux density in the rear part of the coils 5, 6 is increased by the magnetic flux PHI0, a blue beam 7 is increased at the time of deflection to left against CRT scope, and the horizontal deflecting force of a red beam 8 is increased at the time of deflection to right, generating a miss-convergence quantity differed from the miss-convergence quantity generated by the magnetic field distribution of the coils 5, 6. Thus, trilemma can be changed without changing the design of the coils 5, 6.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a deflection yoke used in cathode ray tubes (hereinafter abbreviated as CRT), and in particular to a self-convergence type deflection yoke that facilitates convergence design. It's about York.

[Conventional technology]

Color CR with 3 electron guns arranged in-line
When a deflection yoke with a self-convergence direction is attached to the T, generally the two sides corresponding to the electron beam are
The misconvergence pattern that the colors draw on the screen is the 9th
This is shown in Figures 11 and 11. Further, the 42 colors corresponding to the electron beams on both sides are generally blue (B) and red (R).

In FIG. 9, the horizontal convergence of (7) B/H at the horizontal axis end (hereinafter referred to as the X axis) is expressed as X. We will call it .

In addition, in Figure 1O, the vertical axis end (hereinafter Y l+ll
Y is the horizontal ξ convergence of B/H at We will call it .

Furthermore, in FIG. 11, B at the top corner of the CRT screen is
P Q is the vertical misconvergence of the horizontal line of /H.
Let's call it v.

Now, each of these misconvergence (×...Y...
It is known that there is a correlation between the amounts of convergence of the three regions (hereinafter referred to as trins), and that if the sum of the convergence amounts (hereinafter referred to as trins) is expressed by the following formula, the value will be a constant value. It is being

Trilemma = XH + (-Y.) + P Qv The above equation is considered to be one important index for evaluating the convergence characteristics of a self-convergence type deflection yoke, and it is desirable that the value of this trilemma be zero.

Conventionally, in order to make this trilemma zero, as shown in Figure 12, the length of the horizontal deflection coil and the length of the vertical deflection coil have been optimized, and the relative positions of these horizontal and vertical deflection coils have been optimized. Measures have been taken to adjust the relationship. Note that 9 in FIG. 12 is a saddle-shaped coil.

[Problem to be solved by the invention]

However, it is known that the value of this trilemma changes depending on the size of the CRT screen. With conventional design methods, when the CRT screen size changes, as mentioned above, the design must be changed each time, such as the length and positional relationship of the horizontal and vertical deflection coils, making it difficult to adapt to various CRTs. Designing such a deflection yoke required a great deal of effort and time.

This invention was made to solve the above-mentioned problems, and it is possible to obtain a deflection yophe that can easily accommodate changes in the trilemma due to changes in the size of the CRT screen. The purpose is to [Means for Solving the Problems] The deflection yoke according to the present invention is disposed separately from the main horizontal deflection coil at a position opposite to the rear part of the main horizontal deflection coil on the This is equipped with l pairs of auxiliary coils that selectively shunt a portion of the flow. [Function] In order to selectively shunt a part of the current flowing through the main horizontal deflection coil to the pair of auxiliary coils in this invention, the main horizontal deflection magnetic field can be divided without mechanically changing the length of the main horizontal deflection coil. Change the rear magnetic field strength. [Embodiments] Hereinafter, embodiments of the deflection yoke of the present invention will be described with reference to the drawings. FIG. 1 is a rear view of one embodiment. This first
In the figure, 1 is a deflection yoke, and 2 and 3 are a pair of auxiliary coils arranged symmetrically about the Y axis, which are attached to the rear rear surface of the deflection yoke l on the electron gun side. This pair of auxiliary coils 2.3 are connected to coils 2a, 3aJIr-
It is coiled and structured.

A variable inductor 4 as a variable impedance element is arranged below the pair of auxiliary coils 2.3. The variable inductor 4 is for controlling the horizontal deflection current i1 that is shunted to the auxiliary coil 2.3.

Figure 2 is a circuit diagram of the horizontal deflection coil.
In the figure, 5.6 is a pair of main horizontal deflection coils,
They are connected in parallel to form a parallel circuit. A parallel circuit including an auxiliary coil 2.3 and a variable inductor 4 is connected in series to this parallel circuit.

! , indicates the current in which the horizontal deflection current ■, is shunted by the variable inductor 4. Fig. 3 is a diagram showing the magnetic flux of the auxiliary coil 2.3, and in this Fig. 3, φO is generated when the current ■, shunted by the variable inductor 4, is applied to the coil 2a3a. Shows no magnetic flux.

7 is the blue beam and 8 is the red beam. FIG. 4 (4) shows a YZ-axis sectional view of the deflection yoke l,
Figure 4 (Bl indicates the magnetic flux density distribution of the horizontal deflection magnetic field on the Z-axis. 9 in Figure 4 indicates the saddle type coil which is the main horizontal deflection coil, 10 indicates the rear end, and ll indicates the magnetic flux density distribution of the horizontal deflection magnetic field on the Z-axis. An imaginary rear end portion is shown.Furthermore, 13 is a core made of ferrite, and a vertical deflection coil 12 is wound around this core 13 made of ferrite.

Due to the aforementioned magnetic flux φ0, the distribution of the rear horizontal deflection magnetic flux density in the Z-axis direction changes from the solid line 14 to the broken line 1 in FIG.
5, the rear end 10 of the saddle-shaped coil 9, which is the main horizontal deflection coil, becomes the virtual rear end 1.
This is considered to be equivalent to extending to the broken line part indicated by l.

? When the horizontal deflection magnetic flux density at the rear of the horizontal deflection coil is increased by the aforementioned magnetic flux φO, the horizontal deflection force of the blue beam 7 when deflected to the left and the red beam 8 when deflected to the right increases with respect to the CRT screen. This results in a misconvergence X) which is different from the convergence generated by the magnetic field distribution of the horizontal deflection coil 5.6. FIG. 5 is a diagram showing this situation.

Therefore, the trilemma can be changed without making any design changes to the main horizontal deflection coils 5, 6.

In the above embodiment, electric current was applied to the auxiliary coils 2 and 3 so as to generate the same magnetic flux, but as shown in FIG. And between 33 and 33, the current! , by adding a variable inductor l6 to change the balance of currents IL, I
It is possible to vary R.

In this way, the current IL. When the IR is changed, an imbalance occurs in the horizontal deflection {n flux density at the rear left and right portions of the main horizontal deflection coil 5.6.

Therefore, it is possible to give differentially different magnetic flux densities to both side beams (blue beam 1 red beam) of the CRT. In Fig. 7, φL and φR are respectively applied to coils 2a and 3a. Flowing electricity? JtlL. It shows the magnetic flux generated by IR. Here, if IL>IR,
φL>φR.

FIG. 8 shows a confluence pattern of both side beams (blue beam, red beam) horizontally deflected by φL and φR. As shown in FIG. 7, when φL>φR, the horizontal deflection force of the blue beam is stronger than that of the red beam, so the amplitude of the blue beam becomes larger than the amplitude of the red beam at both ends on the X-axis of the screen.

Therefore, in the case of a reverse misconherence pattern that occurs due to manufacturing errors in the deflection yoke and CRT, that is, when the amplitude of the blue beam is smaller than the amplitude of the red beam,
By adjusting the variable inductor l6, it becomes possible to correct ξ-sconvergence. [Effects of the Invention] As described above, according to the present invention, a pair of auxiliary coils are provided at opposing positions on the X-axis at the rear of the main horizontal deflection coil, and the current flowing through the main horizontal deflection coil is connected to the auxiliary coils. Since a part of the deflection is selectively shunted, it is possible to use an auxiliary coil instead of changing the design of the main deflection coil to correct the trilemma. Accordingly, the main horizontal deflection coil can be shared, and design efficiency can be improved.

In addition, misconvergence caused by manufacturing errors in deflection yokes, CRTs, etc. It also has the advantage of being able to easily correct the asymmetric precepts and providing a highly accurate deflection yoke.

[Brief explanation of drawings]

Fig. 1 is a rear view of a deflection yoke according to an embodiment of the present invention, Fig. 2 is a circuit diagram of a horizontal deflection coil in the above embodiment, and Fig. 3 shows the magnetic flux generated by the rear auxiliary coil in the above embodiment. Explanatory drawings, Figure 4 is a YZ-axis sectional view of the deflection yoke in the same example as above, Figure 4 (marked is a characteristic diagram showing the magnetic flux density distribution of the horizontal deflection magnetic field on the Z-axis in the same example as above, and Figure 5 is a An explanatory diagram showing a misconvergence pattern for explaining the same embodiment as above, FIG. 6 is a circuit diagram of a horizontal deflection coil of a deflection yoke according to another embodiment of the present invention, and FIG. 7 is an embodiment of the embodiment shown in FIG. 6. 8 is an explanatory diagram showing the state of magnetic flux imbalance due to the rear auxiliary coil in the embodiment shown in FIG. An explanatory diagram showing the convergence pattern of (blue beam, red beam), Fig. 9 shows the horizontal direction misconvergence X of B/H at the horizontal axis end (hereinafter referred to as the X axis) in a conventional deflection yoke. Explanatory diagram, 1st
Figure 0 shows the horizontal misconvergence Y. FIG. 11 is an explanatory diagram showing the vertical misconvergence PQv of horizontal lines of B/H at the four corners of the CRT screen in a conventional deflection yoke, and FIG. 12 is an explanatory diagram showing the trilemma in the conventional deflection yoke. It is an explanatory view showing an adjustment method. ■... Deflection yoke, 2, 3... Auxiliary coil, 2a,
3a... Coil, 2b, 3b... Magnetic core for trapping coil, 4, l6... Variable inductor, 5.6... Main horizontal deflection coil, 9... Saddle type coil. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] In a deflection yoke used in a cathode ray tube having multiple electron guns, a pair of auxiliary coils are provided separately from the main horizontal deflection coil at opposing positions on the X-axis at the rear of the main horizontal deflection coil. A deflection yoke characterized in that the auxiliary coil is provided with a variable impedance element that selectively shunts a part of the current flowing through the main horizontal deflection coil so as to generate a magnetic field in the same direction as the magnetic field.