JPH03149733A - Purity correcting device - Google Patents

Abstract

PURPOSE:To correct the purity error over the whole face of a cathode-ray tube without changing the picture element distortion quantity by arranging purity magnetic field generation yokes on the neck tube of a color television cathode-ray tube, and feeding the correction currents synchronous with the horizontal deflection current and vertical deflection current and the DC current. CONSTITUTION:At least two pairs of purity magnetic field generation yokes (DY) 1 and 3 provided with at least two pairs of coils 1a-1d generating two pairs of electron beam deflection magnetic fields perpendicular to each other are provided in planes vertical to the tube axis of the neck tube of a cathode- ray tube 5. A purity magnetic field generation yoke driving circuit 18 which sets the currents with optional magnitudes synchronous with the horizontal deflection current and vertical deflection current in coils 1a-1d and drives coils 1a-1d so as to generate the purity magnetic field with the optional desired magnitude and direction at each position of the display screen of the cathode-ray tube 5 is provided. Purity adjustment can be performed over the whole face of the cathode-ray tube 5 without changing the picture element distortion quantity by adjusting the position and the incidence angle of an electron beam when it enters the magnetic field generated by the deflection yokes DY 1 and 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a purity correction device for a color television.

[Conventional technology]

The purity of shadow mask type color television depends on the direction and angle of incidence of the electron beam when it enters the shadow mask, and these direction and angle of incidence vary depending on the product.

The doming of the shadow mask, the influence of the earth's magnetic field, etc. may cause the value to differ from the design value.

In order to correct the error with the above design value, a static magnet for pipulity correction is conventionally attached to the neck of the well-known CRT, and by adjusting this static magnet, the error with the design value can be corrected. was being corrected.

However, since the purity error varies depending on the location on the cathode ray tube surface, it is impossible to perform purity correction on the entire cathode ray tube surface using the above method.

Furthermore, as described in Japanese Patent Application Laid-Open No. 63-37793, in order to correct the amount of movement of the electron beam toward the center of the cathode ray tube surface caused by doming, a magnetic field in the rotational direction that changes over time is applied to the cathode ray tube panel surface. By generating this, the purity correction was performed.

However, with this method, it is impossible to correct an electron beam that moves in a direction other than the center of the cathode ray tube surface, or to perform dynamic purity correction over the entire cathode ray tube surface.

According to the conventional correction method described above, it is impossible to correct the purity error caused by the incident direction and angle of incidence of the electron beam, which has an arbitrary error from the designed value, over the entire surface of the cathode ray tube.

[Problem to be solved by the invention]

The present invention provides a integrity correction device that can correct integrity errors caused by product variations, shadow mask doming, the influence of geomagnetism, etc. over the entire surface of a color television cathode ray tube without changing the amount of image distortion. It's about doing.

[Means to solve problem a]

In order to solve the above-mentioned problems, the present invention uses a purity magnetic field generating yoke PY that can arbitrarily set the direction of the magnetic field within the same plane and change its magnitude to a color television cathode ray tube. The convergence yoke C
Y is placed on the neck tube of a color television cathode ray tube, and by passing a correction current synchronized with the horizontal deflection current and vertical deflection current from a digital comparator and Zens correction circuit, when it enters the magnetic field created by the deflection yoke DY-, by adjusting the position and incidence angle of the electron beam.

Adjusts the utility across the entire CRT without changing the amount of image distortion.

(1. Effect) According to the present invention, it is possible to correct purity errors caused by product variations, doming of shadow masks, and the influence of earth's magnetic field over the entire surface of a color chi-revision cathode ray tube without changing the amount of image distortion. .

〔Example〕

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention,
Figure 1 is a side view showing how PY, CY, and DY are installed.
FIG. 2 is a cross-sectional view taken along line 8-A' of PYI in FIG.

In Figure 1, l is the first PY, 2 is cy, and 3 is the second PY.
PY, 4 is DY, and 5 is a cathode ray tube for color television.

In Fig. 2, la, lb, lc, and ld are coils for generating a purity correction magnetic field, and 1e is a coil la.
, the vertical purity correction magnetic field generated by the coil IC, if is the coil lb.

1g is a polarity correction composite magnetic field of vertical polarity correction magnetic field le and horizontal polarity correction magnetic field 1f,
18 is a PY drive circuit which will be described later.

18f1 and 18f2 are independent amplifiers.

The coil la and coil le are connected to an amplifier 18fl, and the coil tb and coil ld are connected to an amplifier 18f2. The M amplifier 18fl and the amplifier 18f2 can set dynamic currents and direct currents synchronized with the horizontal and vertical deflections, and by muting the currents, the direction and magnitude of the purity correction composite magnetic field 1g can be changed. Also 2nd P
Y3 also has the same function as explained in the first PYI.

FIG. 3 is a diagram illustrating the operation of the embodiments shown in FIGS. 1 and 2, and shows changes in the orbit of the electron beam due to PY.

In Fig. 3, 6 to 13 are line segments indicating the magnetic field range, 14 is the cathode ray tube surface, 15 is the trajectory of the electron beam without PY correction, and 16 is the trajectory of the electron beam with PY correction. be. Section 647 is the magnetic field range due to the first PYI, Section 8-9 is the magnetic field range due to CT4, Section 1-0
-11 is the magnetic field range due to the second PY3, and section 12-13 is the magnetic field range due to DY4.

The electron beam 16 passing through the section loaf is electromagnetically deflected by the first PYl and passes through a different trajectory from the trajectory 15. Also, the electron beam 16 is in the section 8-9.

It is electromagnetically deflected by CT4, electromagnetically deflected by the second PY3 in section 10-11, and further electromagnetically deflected in section 12-13.
is electromagnetically deflected by DY4, and the cathode ray tube surface 1
4, the same point 17 as trajectory 15 is reached. That is, the electromagnetic deflection amount set by the second PY3 in the section 10-11 is set so as to reach the same point 17 as the electron beam trajectory 15 on the cathode ray tube surface 14.

Therefore, by combining the two sets of the first PYI and the second PY3, the electron beam trajectory 15 on the cathode ray tube surface 14 is
At the same point 17, it is possible to set electron beam trajectories 16 with different incident directions and angles.

FIG. 4 is a diagram showing a configuration diagram of the PY drive circuit, and 1
8a is a data block, 18b is a beam trajectory calculation block, 18c is a CY feedback data calculation block, 18d is a correction data memory block, 18
e is the D/A converter, 18f is the amplifier block, 1
9 is a digital convergence circuit.

In FIG. 4, the desired adjustment amount of the current required for deflection of the first PYI is manually or automatically determined and input into the data block 18a. Thereafter, the correction current data of the first PYl is stored in the correction data memory 18d.

Further, the correction current data of the second PY3 is determined by the beam trajectory calculation block 18b according to the correction current value of the first PYI. Thereafter, the correction current data of the second PY3 is stored in the correction data memory 18d. The 1st PYI and 2nd PY3 stored in the correction data memory 18d
The correction data is converted into analog data by the D/A converter 18e, amplified by the amplifier block 18f, and sent to the first PYI and the second PY3.

In addition, the CY feedback data calculation block 18c calculates the first P from the data in the data single block 18a.
Feedback data corresponding to the YI correction data is calculated and the data is output to the digital convergence circuit 19.

FIG. 5 is a diagram showing another embodiment of the present invention, and the same reference numerals in the figure have the same functions as in FIG. 1. Furthermore, this embodiment is characterized in that the position of CY2 is placed closer to DY4 than the second PY3, and can be applied to cases where the position of CY2 is fixed due to the structure of the electron gun and the arrangement shown in FIG. 1 is impossible.

FIG. 6 is a diagram showing another embodiment of the present invention, and the same reference numerals in the figure have the same functions as in FIG. 1. Further, this embodiment is characterized in that the position of CY2 is placed closer to the CPT socket than the first PY, and can be applied to cases where the position of CY2 is fixed due to the structure of the electron gun and the arrangement shown in FIG. 1 is impossible.

FIG. 7 is a diagram showing another embodiment of the present invention, with 20
are four magnetic poles PY, 20a, 20b.

20c and 20d are purity correction magnetic field generation coils, 20
e, 20f, 20g, 20h are centripetally shaped magnetic poles, 2
01 is a vertical purity correction magnetic field generated by the purity correction magnetic field generation coils 20a and 20c, and 20j is a horizontal purity correction magnetic field generated by the purity correction magnetic field generation coils 20b and 20d.

In FIG. 7, the magnetic pole 20e has a centripetal shape.

2Of, 20g, and 20h are used, and the magnetic poles 20e, 20f, 20g, and 20h are used.

Vertical and horizontal purity correction magnetic fields 20i.

20j can be made into a substantially uniform magnetic field, and the cathode ray tube surface 14
The deterioration of the electron beam spot shape can be significantly improved.

FIG. 8 is a diagram showing another embodiment of the present invention, 21
is a six-pole magnetic pole PY, 21 a to 21 j are purity correction magnetic field generation coils, and 21 is a purity correction magnetic field generation coil 21 a, 21 b, 21 c.

A vertical purity correction magnetic field 211 is generated by the purity correction magnetic field generating coils 21g, 21h, 21i, and 21j.

In FIG. 8, it is characterized by the use of a six-pole magnetic pole PY21, and the vertical and horizontal purity correction magnetic fields 21 and 211 have a substantially uniform magnetic field by forming the magnetic poles into a six-pole configuration. Further, in the vertical and horizontal purity correction magnetic fields 21, 21
1 has a more uniform magnetic field than the vertical and horizontal purity correction magnetic fields 201° 20j of the embodiment shown in FIG.
Deterioration of the electron beam spot shape on the cathode ray tube surface 14 can be further improved than in the embodiment shown in FIG.

FIG. 9 is a diagram showing another embodiment of the present invention, 22
is a py@ dynamic circuit for flowing direct current to PY.

22a is a DC power supply, and 22b is a variable resistor that makes the DC current value variable. In other countries, the same reference numerals as in FIG. 1 operate in the same way.

A major feature of FIG. 9 is that it is composed of a PY Ill and a drive circuit that flows a DC current.

The direct current can be arbitrarily set by using a variable resistor 22b, for example lf. Therefore, static purity correction can be performed over the entire surface of the color television cathode ray tube.

The present invention is effective when there are relatively few fluctuations in purity, and has the advantages of simple construction and cost reduction.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

In the present invention, a color television CRT,
The direction and angle of incidence of the electron beam on the shadow mask can be adjusted as desired. Therefore, dynamic purity correction can be performed without changing the amount of image distortion at each position of the color television cathode ray tube.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention. A side view showing the youthful state of CY and DY, Figure 2 is the first
3 is a characteristic diagram showing the effect of trajectory deflection of the electron beam by PY in the embodiment of FIG. 1, FIG. 4 is a block diagram of the Pym dynamic circuit, and FIG. , FIG. 6 is a side view showing another embodiment of the present invention, and FIG. 7 is a side view showing another embodiment of the present invention, and FIG. 7 shows a PY core arranged in a centripetal shape with respect to the neck tube of a color television cathode ray tube and a substantially uniform magnetic field in order to generate a substantially uniform magnetic field. FIG. 8 is a cross-sectional view showing a substantially uniform magnetic field generating coil using six magnetic poles for generating a substantially uniform magnetic field. FIG. 9 is a cross-sectional view showing a substantially uniform magnetic field generating coil using six magnetic poles for generating a substantially uniform magnetic field. It is a side view showing an example. l...No. IPY. 2-...CY. 3.--2nd PY. 4...-DY. 5...Color television CRT. 1a, 1b, 1c, 1d - Purity correction magnetic field generating coil. 1e--Purity correction magnetic field generating coil la. The vertical purity correction magnetic field generated by 1c. 1f -- Purity correction magnetic field generating coil lb. The horizontal purity correction magnetic field generated by 1d. 1g... Composite magnetic field vector of vertical purity correction magnetic field 1e and horizontal purity correction field i if. 6 to 13...Line segments for indicating the magnetic field range. 14... Cathode ray tube surface. 15.--Trajectory of electron beam without PY correction. 16... Trajectory of electron beam with PY correction. 17... The destination of the electron beam on a color television CRT. 18.--pym motion circuit. 18a... - data person Ka block. 18b--Beam trajectory calculation block. 18c...-CY feedback data calculation block 18d...Correction data memory block. 18a--D/A converter. 18f--Amplifier block 18f1, 17f2--Amplifier in amplifier block 17f. 19...Digital convergence circuit. 20.-4 magnetic pole PY. 20a, 20b, 20c, 20d - Purity correction magnetic field generation coil. 20e, 20f, 20g, 20b - Centripetally shaped magnetic poles. 201...Purity correction magnetic field generation coil 20a. The vertical purity correction magnetic field generated by 20c. 20j...Purity correction magnetic field generating coil 20b. The horizontal purity correction magnetic field generated by 20d. 21-1.6 magnetic pole PY. 21a to 21j--Purity correction magnetic field generation coil. 21k -- Purity correction magnetic field generating coil 21a. 21b, 21c, 21d, 21e. Vertical purity correction magnetic field generated by 21f. 211...Purity correction magnetic field generating coil 21g. Horizontal purity correction magnetic field generated by 21h, 21i, and 21j. 22-.py drive circuit. 22a...DC power supply. 22b...variable resistor.

Claims (1)

[Claims] 1. A purity correction device for a color TV cathode ray tube, which generates two sets of electron beam deflection magnetic fields perpendicular to each other along the neck tube of the cathode ray tube in a plane perpendicular to the tube axis. At least two sets of purity magnetic field generating yokes each having at least two sets of coils are provided, and
By setting a current of an arbitrary magnitude in each coil in synchronization with the horizontal deflection current and the vertical deflection current, a purity magnetic field having an arbitrary desired magnitude and direction is generated at each position of the cathode ray tube display screen. A purity correction device comprising a purity magnetic field generation yoke drive circuit for driving each of the coils. 2. The purity correction device according to claim 1, wherein a convergence correction yoke is provided in addition to the purity magnetic field generation yoke along the neck tube of the cathode ray tube, and a horizontal deflection is applied to a coil wound around the convergence correction yoke. A convergence circuit that generates a convergence correction magnetic field at each position of a cathode ray tube display screen by setting an arbitrarily large current in synchronization with the current and the vertical deflection current. correction device. 3. The purity correction device according to claim 2, wherein the purity magnetic field generation yoke drive circuit provides the convergence circuit with correction data for correcting the amount of misconvergence that occurs with the purity correction. Purity correction device. 4. The purity correcting device according to claim 1, wherein the purity magnetic field consists of a substantially uniform magnetic field. 5. In the purity correction device according to claim 1, the purity magnetic field generating yoke is comprised of a yoke with four magnetic poles centripetal to the neck tube of a cathode ray tube, and the purity magnetic field is formed by the four magnetic poles. A purity correction device comprising a substantially uniform magnetic field. 6. The purity correction device according to claim 1, wherein the purity magnetic field generating yoke is composed of a yoke with six pole magnetic poles having a centripetal shape with respect to the neck tube of a cathode ray tube, and the purity magnetic field is formed by the six pole magnetic poles. A purity correction device comprising a substantially uniform magnetic field. 7. The purity correction device according to claim 2, wherein the convergence yoke is disposed between the two sets of purity magnetic field generation yokes. 8. The purity correction device according to claim 2, wherein the convergence yoke is arranged on the deflection yoke side of the purity magnetic field generation yoke. 9. The purity correction device according to claim 2, wherein the convergence yoke is disposed on the cathode ray tube socket side of the purity magnetic field generation yoke. 10. A purity correction device for a color TV cathode ray tube, which includes two sets of coils that generate two sets of electron beam deflection magnetic fields perpendicular to each other in a plane perpendicular to the tube axis along the neck tube of the cathode ray tube. What is claimed is: 1. A purity correction device comprising: a set of purity magnetic field generating yokes, and a DC current is caused to flow through each of the coils. 11. The purity correction device according to claim 10, wherein a convergence correction yoke is provided in addition to the purity magnetic field generation yoke along the neck tube of the cathode ray tube, and a horizontal deflection is applied to a coil wound around the convergence correction yoke. A convergence circuit that generates a convergence correction magnetic field at each position of a cathode ray tube display screen by setting a current of arbitrary magnitude in synchronization with the current and the vertical deflection current. correction device. 12. The purity correcting device according to claim 10, wherein the direct current is made variable.