EP1139380A1 - Deflection device for use in a color cathode-ray tube - Google Patents

Abstract

The unit has a vertical deflection coil pair (120,130), a horizontal deflection coil pair (110), whereby at least one pair is divided into at least two parts, of which one part is provided for correcting convergence errors and the other for correcting geometry errors and the corrections are carried out independently of each other. Independent claims are also included for the following: a color image electron beam tube and a visual display unit containing a color image electron beam tube.

Description

The invention relates generally to a deflection unit for mounting on a color image tube and is particularly concerned with the correction of convergence errors and geometry errors in such a deflection unit.

Deflection units are mounted on an electron beam tube around the electron beams distract from the screen in the X and Y directions. The deflection unit is there essentially consisting of two pairs of coils and a ferrite core, which is used for the return of the magnetic flux. One pair of coils creates a magnetic field that the Deflects electron beams in the horizontal direction (X direction) while the other Coil pair of vertical deflection (Y direction) is used.

A frequently used design of modern color picture tubes is the in-line arrangement on, in which the beam generation systems are arranged side by side in one plane are. In such systems, three electron beams are generated, the axes of which are coplanar run and converge on the screen. That through for this kind of Color picture tubes suitable deflection generated image is self-converging, coma-free and has essentially no north-south rest distortions. This will be in the essentially achieved by changing the field shape in the Z direction. The Z direction is the axis running towards the screen.

Figures 1a and 1b illustrate the deflection fields for the vertical and horizontal Deflection direction in a deflection unit for in-line color picture tubes. As can be seen in the figures the field distributions are in the rear areas 10, 40 of the deflection unit of those of the middle section 20 and the front section 30, 50 of the deflection unit different.

The field shapes that can be used in such deflection units are shown in FIG 1c, the left field distributions in pillow form and the right in barrel form are. The upper field distributions in FIG. 1c are those for the vertical deflection direction used while the lower field representations are used for horizontal deflection be applied.

As can be seen from FIG. 1a, the vertical deflection direction is in the rear area the deflection unit a pillow-shaped, in the middle a barrel-shaped and a pillow-shaped deflection field is used in the front area. For the horizontal The deflection unit has the deflection direction in the rear area, as shown in FIG. 1b a barrel-shaped and in the front area a pillow-shaped deflection field. As described above, these arrangements make it self-converging, coma-free and north-south image distortion free.

Due to assembly errors of the picture tubes and the deflection units can essentially two types of errors occur: convergence errors and geometry errors. Convergence error are available when the color separation images are no longer congruent are. In contrast, there are geometry errors when the raster image is distorted on the screen. Convergence and geometry errors can also occur simultaneously.

An example of the presence of convergence errors is shown in Figure 2, where due of construction tolerances of the blue beam no longer with the red beam to cover can be brought. To correct such a convergence error is used in conventional Arrangements the deflection unit usually tilted, as shown in the figures 3a and 3b are shown for the X and Y directions, respectively.

This error correction has the disadvantage that due to the inhomogeneous fields in the front area of the deflection unit generates undesirable asymmetrical geometry errors can be. This will continue with reference to Figures 4a and 4b clear. FIG. 4a shows an ideal grid and FIG. 4b shows a distorted grid, caused by tilting the deflection unit in the Y direction.

Another correction device for coma errors known from the prior art, which occur because the grid dimensions of the three electron beams in the in-line type are different, which is a consequence of the eccentric location of the outer in-line cannons related to the horizontal or vertical deflection fields, includes an additional Coil pair, which is mechanically firmly connected on the back of the deflection unit is. This pair of coils allows suitable circuitry measures a correction of the convergence error. Although the additional pair of coils Convergence correction without significant geo-gear influence is possible, however the circuitry measures required for this are very complex.

The invention is therefore based on the object of a simplified deflection unit Specify mounting on a color image cathode ray tube, which improved convergence and geometry error correction. Another object of the invention is the provision of associated color image cathode ray tubes and display devices.

According to the invention comprises a deflection unit for mounting on a color image tube a vertical deflection coil pair and a horizontal deflection coil pair, wherein at least one of the coil pairs is divided into at least two parts is. One part is used to correct convergence errors and the other part to correct of geometry errors. The respective corrections are independent of the other Correction can be carried out.

This arrangement according to the invention has the advantage that it is a convergence correction allows without generating a significant geometry error.

Due to the separate adjustment of the two types of errors, deflection units are also included high sensitivity especially with regard to a correction of the coma error realizable.

In preferred configurations, the two parts are mechanically independent and spatially separated from one another, the one provided for correcting the geometry errors Part is closer to the screen level than that for correcting the convergence errors intended part.

To achieve a different correction behavior, only this can be done Vertical deflection coil pair or only the horizontal deflection coil pair or both coil pairs be divided.

Preferred configurations are defined in the subclaims.

Fig. 1a die in Z-Richtung veränderliche Feldform des Ablenkfeldes für die vertikale Ablenkrichtung zeigt;

Fig. 1b die in Z-Richtung veränderliche Feldform des Ablenkfeldes für die horizontale Ablenkrichtung zeigt;

Fig. 1c die kissen- und tonnenförmigen Ablenkfelder in horizontaler und vertikaler Ablenkrichtung verdeutlicht;

Fig. 2 eine Darstellung eines Konvergenzfehlers durch Aufbautoleranzen der Bildröhre und der Ablenkeinheit ist;

Fig. 3a und Fig. 3b die herkömmliche Kippkorrektur von Konvergenzfehlern in X-und Y-Richtung verdeutlichen;

Fig. 4a eine Abbildung des idealen Rasters ist;

Fig. 4b eine Abbildung eines Rasters mit asymmetrischen Geometriefehlern durch Kippen der Ablenkeinheit in Y-Richtung ist;

Fig. 5 ein Ausführungsbeispiel einer an eine Farbbild-Elektronenstrahlröhre montierten Ablenkeinheit in Schnittdarstellung zeigt;

Fig. 6a eine Schnittdarstellung mit Blick in Z-Richtung zur Verdeutlichung der Konvergenzfehlerkorrektur durch eine Y-Bewegung darstellt;

Fig. 6b eine Darstellung des durch die Anordnung der Figur 6a korrigierbaren Konvergenzfehlers ist;

Fig. 7a eine der Darstellung der Figur 6a entsprechende Anordnung für eine Korrektur in X-Richtung zeigt; und

Fig. 7b den durch diese Anordnung korrigierbaren Konvergenzfehler verdeutlicht.

The invention will now be explained in more detail with reference to the accompanying drawings, in which:

1a shows the field shape of the deflection field, which is variable in the Z direction, for the vertical deflection direction;

1b shows the field shape of the deflection field, which is variable in the Z direction, for the horizontal deflection direction;

1c illustrates the pillow-shaped and barrel-shaped deflection fields in the horizontal and vertical deflection direction;

Fig. 2 is an illustration of a convergence error due to build-up tolerances of the picture tube and the deflection unit;

3a and 3b illustrate the conventional tilt correction of convergence errors in the X and Y directions;

Figure 4a is an illustration of the ideal grid;

4b is an illustration of a grid with asymmetrical geometric errors by tilting the deflection unit in the Y direction;

5 shows an exemplary embodiment of a deflection unit mounted on a color image electron beam tube in a sectional illustration;

6a shows a sectional view with a view in the Z direction to illustrate the convergence error correction by means of a Y movement;

FIG. 6b is an illustration of the convergence error that can be corrected by the arrangement of FIG. 6a;

7a shows an arrangement corresponding to the illustration in FIG. 6a for a correction in the X direction; and

7b illustrates the convergence error that can be corrected by this arrangement.

Preferred embodiments of the invention will now be described with reference to the figures explained in more detail.

FIG. 5 shows a color image tube with an attached deflection unit in FIG Sectional view. The one attached to the neck of the color picture tube 100 includes Deflection unit first a horizontal coil 110, a vertical coil 120, 130 and one Ferrite core 140. As can be seen in the figure, the vertical coil is in a front Coil part 120 and a rear coil part 130 divided. By means of the front A geometry error can be corrected and adjusted in coil part 120. The rear coil part 130 enables independent correction of convergence errors, such as one Coma error.

The convergence error correction by the arrangement shown in Figure 5 will be referenced 6 and 7 now explained in more detail. Figure 6a shows one in the Y direction displaced vertical coil 130, whereby the convergence errors shown in Figure 6b have it corrected without generating geometry errors. In the shown in Figure 7a Arrangement, the rear vertical coil part 130 is displaced in the X direction, which enables the correction of another convergence error, which is illustrated in FIG. 7b is.

Although the vertical coil pair is subdivided in the embodiment described, can in another embodiment of the invention, the pair of horizontal coils can be divided. In a further preferred embodiment of the invention, both pairs of coils divided, which results in different correction behavior.

In a further preferred embodiment, the respective coil pair is not only in divided into two parts. Rather, it can be divided into three or more parts preferably a further improved error correction and convergence or geometry adjustment achieve.

The invention can preferably be used in saddle-saddle deflection units, but also in saddle-toroid deflection units apply. The invention is preferably found in "pure flat" color picture tubes Application.

Claims (10)

Deflection unit for mounting on a color image tube (100), comprising: a pair of vertical deflection coils (120, 130) and a pair of horizontal deflection coils (110), wherein at least one of the coil pairs is divided into at least two parts, one part of which is provided for correcting convergence errors and the other part for correcting geometric errors, and the respective corrections can be carried out independently of the other correction. Deflection unit according to claim 1, wherein the at least two parts are spatially separated and are arranged mechanically independently of each other and for the correction of Geometry errors provided part closer to the screen of the color image tube is located than that intended for the correction of convergence errors Part. Deflection unit according to claim 1 or 2, wherein the divided coil pair the horizontal deflection coil pair is. Deflection unit according to claim 1 or 2, wherein the divided coil pair the vertical deflection coil pair is. Deflection unit according to one of claims 1 to 4, further means for fine adjustment of the Comprehensive convergence error correction and / or geometry error correction. Deflection unit according to one of Claims 1 to 5, set up for use with an in-line color picture tube. Deflection unit according to one of claims 1 to 6, wherein the deflection unit is a saddle-toroid deflection unit is. Deflection unit according to one of claims 1 to 6, wherein the deflection unit is a saddle-saddle deflection unit is. Color image tube with a deflection unit according to one of claims 1 till 8. A display device comprising a color image tube (100) and a deflection unit according to one of claims 1 to 8.

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