JPH0136283Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention is an electromagnetic deflection yoke for use in display cathode ray tubes, such as color television receivers, for correcting positional deviations of electron beams in color television receivers, such as color shifts, caused by various variations in the deflection yoke. It concerns York. Generally, the deflection yoke attached to a CRT has a ferrite core with a vertical deflection coil and a horizontal deflection coil attached to it to generate a vertical deflection magnetic field and a horizontal deflection magnetic field to control the direction of the CRT's electron beam. Due to variations in the dimensions of the coils and uneven winding of the coils, some of them are of poor quality, causing color shifts in television receivers. Conventionally, these materials are made of so-called ferrite rubber sheets, which are made by kneading fine powders such as Mn-Zn ferrite in rubber or PVC resin at a volume ratio of about 6:4, and are 0.5 mm thick and 10 mm thick. It is cut into sheets of approximately 20 mm and pasted on the inner surface of the deflection yoke, and by selecting the number of sheets to be pasted and the position at which they are pasted, the magnetic field distribution is changed and color shift is corrected. However, it is extremely difficult to affix more than three sheets because the CRT is mounted quite closely inside the deflection yoke, and even if the affixing position is near the center of the yoke and the effect is strengthened, it is not possible to affix more than 3 sheets. Currently, about 10% of the deflection yokes produced cannot be repaired and are discarded. The present invention replaces the conventionally used ferrite rubber magnet sheet by incorporating soft magnetic metal/alloy fine powder, which has a magnetic flux density more than twice that of ferrite, into rubber or flexible plastic. This is characterized by processing this into a sheet and attaching it to the inner wall of the electromagnetic deflection yoke. The saturation magnetic flux density of ferrite is approximately 3000gauss
Fe, Fe−Co, Fe−Al, Fe−Al−
Alloys such as Si, Fe-Si, and Fe-Ni are soft magnetic materials with saturation magnetic flux densities of 6,000 gauss or more, and when they are contained in rubber or plastic at a volume ratio of 60% or more, even a single piece becomes ferrite. It has more than twice the effect of pasting two ferrite rubber sheets, and in some cases it can achieve the same effect as five ferrite rubber sheets. Deflection yokes, which were conventionally discarded as being impossible to correct, can now be easily corrected, making it possible to extremely increase productivity. However, the metals and alloys used in this invention have an extremely low electrical resistance of less than 100μΩ・cm, so when used in a high frequency band for a long time, the temperature of the sheet will decrease several times due to heat generation due to eddy current.
Since the temperature rises by 10℃, it is necessary to use magnetic powder with a particle size finer than 50 mesh. The present invention will be explained with reference to the drawings. The figure shows an electromagnetic deflector in which a sheet made of soft magnetic metal or alloy fine powder, which has a magnetic flux density more than twice as high as that of the ferrite of the present invention, is contained in rubber or flexible plastic and processed into a sheet shape. It is a cross-sectional view of the opening of the yoke, in which 1 is a horizontal deflection coil, 2 is a vertical deflection coil, 3 is a mounting bracket for both the coils, 4 is a ferrite yoke, 5 is a sheet of the present invention, and 6 is a cathode ray tube. Table 1 shows the degree of correction of color shift by a sheet made of rubber or plastic containing a soft magnetic material with a saturation magnetic flux density of 6000 gauss or more, standardized by the value of a ferrite sheet. I can understand that it is effective.

[Table] The mixing ratio of the metal/alloy magnetic material to rubber and plastic was approximately 3:1 by volume. As described above, according to the electromagnetic deflection yoke of the present invention, it is possible to extremely effectively correct the positional deviation of the electron beam of the display cathode ray tube, for example, the color deviation.

[Brief explanation of the drawing]

The figure is a sectional view of the opening of the electromagnetic deflection yoke to which the sheet of the present invention is attached. 1... Horizontal deflection coil, 2... Vertical deflection coil, 3... Coil mounting bracket, 4... Ferrite yoke, 5... Sheet of the present invention, 6... CRT.

Claims (1)

[Scope of utility model registration request] In the electromagnetic deflection yoke used in cathode ray tubes for displays, the saturation magnetic flux density is
An electromagnetic deflection yoke characterized by attaching to the inner wall of the electromagnetic deflection yoke a sheet containing soft magnetic metal or alloy powder of 6000 gauss or more and less than 50 mesh in rubber or plastic in a volume ratio of 60% or more.