JPS5840583A - Crt display - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube (hereinafter referred to as CRT) display device. In the deflection device for the CRT display, other components having a magnetic field distribution may come close to the deflection coil and adversely affect the deflection magnetic field created by the deflection coil. The purpose of the present invention is to provide a magnetic field that cancels out the above-mentioned adverse effects, and to correct the distortion of the deflection magnetic field that occurs due to the adverse effects 1.Here, other components having magnetic field distribution include a flyback transformer, These include amplitude adjustment coils, linearity coils, distortion correction transformers, etc.

In recent years, CRT display devices using in-line picture tubes, whose application has been rapidly expanding in all fields, have a very wide magnetic field distribution created by the deflection coil used in the in-line method, unlike the conventional delta method. Therefore, this magnetic field distribution is easily coupled to components having other magnetic field distributions. Furthermore, when a magnetic material approaches a deflection coil, it affects deflection distortion and color purity, so careful consideration is required for practical application.

Therefore, in order to prevent this kind of problem from occurring, conventional design considerations have been made to ensure a physical distance between the deflection coil and the Kaimei components. However, in terms of design, maintaining a sufficient distance between the CRT display device and the deflection coil increases the size of the CRT display device itself, which goes against the demands of the market for low cost and compactness.

Conventional examples are shown in Figs. 1 to 4. In FIG. 1, 1 is an in-line picture tube, 2 is a deflection coil, and 3 is a flyback transformer.

In FIG. 1, the deflection coil 2 has a very wide magnetic field distribution, so it is magnetically coupled to the flyback transformer 3.
As shown in FIG. 2, deflection distortion is produced on the left side of the screen.

The reason for this will be explained using FIGS. 3A and 3B. In FIG. 2, the frame 4 indicates a CRT screen, the solid line a indicates a normal image, the broken line indicates an abnormal image subjected to deflection distortion, respectively.

In FIG. 3A, Ml is the magnetic field created by the deflection coil 2. Because the beam current flows toward the spine of the paper rather than the surface of the paper,
According to Fleming's left hand rule, the magnetic field M1(L) in the left half
The beam current moves to the left, and the magnetic field M in the right half
1(R) causes the beam current to move to the right and normal deflection operation is performed. Here, F(R) and F(L) are the beam currents due to the different colors M1(R) and Ml(L) It shows the direction of the applied force. The reason why deflection distortion occurs will be specifically explained with reference to FIG. 3B.

In FIG. 3B, M2 is the magnetic field produced by the flybank transformer 3 that adversely affects the deflection. When this M2 is coupled to the magnetic field bj1 (L) created by the deflection coil 1, points A and B as shown in the same figure.

Since a force F (a force perpendicular to M2 according to Fleming's left-hand rule) is applied to the beam current of C in addition to the normal deflection, it causes the deflection distortion shown in Figure 2. be. FIG. 4 shows this state of deafness on the screen.

Here the electron beam A/.

B/ and C' correspond to A, B, and C in FIG. 3, respectively.

The present invention eliminates the above-mentioned conventional drawbacks.

FIG. 5 shows an embodiment of the present invention.

In FIG. 6, numerals 1 to 3 are the same as in FIG. 1, and are an in-line picture tube, a deflection coil, and a flyback transformer, respectively. Reference numeral 6 denotes a device that applies a magnetic field in order to cancel out the adverse effects, which is a feature of the present invention. To explain in detail below, the magnetic field generated by the flyback transformer 3, that is, M2 in FIG.
Due to the magnetic field of -M2, M2-M2=O, the magnetic field that adversely affects the deflection coil 2 disappears, and a normal image shown by the solid line a in FIG. 2 is reproduced. Note that the magnetic field device 4 can be replaced with, for example, an amplitude adjustment coil, and whether the magnetic field generated by the flyback transformer 3 is M2 or -M2, the desired magnetic field can be realized by simply switching the connection wires. It is possible to provide an extremely simple device that can be used in a variety of ways.

As is clear from the above embodiments, according to the present invention, it is possible to cancel out the magnetic field that adversely affects the magnetic field created by the deflection coil in an extremely inexpensive and easy method, and therefore it is possible to bring other parts close to the deflection coil. It enables high performance, low cost, and compact design.It also makes it possible to cancel out image distortion by using a component called an amplitude adjustment coil, which is almost always required in CRT display devices. Furthermore, regardless of the polarity or direction of the magnetic field coupled to the deflection coil, the direction of connection and installation of the amplitude adjustment coil can be appropriately set to eliminate the magnetic field that has an adverse effect. can be easily canceled out.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a schematic configuration of a conventional cathode ray tube display device, FIG. 2 is a diagram showing an image on the screen for explaining problems in the conventional example, and FIGS. 3A and B are diagrams of the conventional example. FIG. 4 is a diagram showing the problem on the screen, and FIG. 6 is a diagram showing the cause and appearance of the problem on the cathode ray tube. FIG. It is a figure showing a schematic structure. 1... In-line video tube, 2...
Deflection coil, 3...Flyback transformer, 5
... A magnetic field device that creates a magnetic field that cancels the magnetic field generated by a flyback transformer. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 3 (A) Figure 3 (8) Figure 4

Claims (2)

[Claims] (1) It is equipped with an in-line picture tube equipped with a deflection coil, and in response to the presence of a magnetic field that affects the deflection magnetic field obtained by the deflection coil, it has a device that applies a magnetic field that cancels out the influencing magnetic field. Characteristic cathode ray tube display device. (2) A cathode ray tube display device according to claim 1, wherein the device for applying a magnetic field that cancels out an influencing magnetic field is constituted by an amplitude adjustment coil.