DE1279067B - Device for correcting raster registration errors for a three-color television picture tube - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. α .:

H04n

German class: 21 al -34/11

Number: 1279 067

File number: P 12 79 067.9-31 (R 41050)

Filing date: July 9, 1965

Open date: October 3, 1968

The invention relates to a device for correcting grid misregistration for a Three-color television picture tube in which three electron beams, which are initially roughly parallel to the tube axis and extend at equal angular distances from one another with respect to this, through one to the tube axis at least approximately coaxial deflection coil arrangement in two directions grid-like and further each radially deflectable with respect to the tube axis by an arrangement for dynamic convergence and one of the electron beams in the one raster deflection direction with respect to the tube axis is offset.

There are known cathode ray tubes for color television receivers, which with three electron beams * 5 work that selectively excite groups of fluorescent substances that emit light of three different colors, such as red, Green and blue, emit. The luminescent screen of such a tube consists of a multitude of in Phosphor dots arranged in groups of three, including corresponding openings in a shadow mask are assigned, which is arranged behind the luminescent screen. The electron beams prevail the openings of the shadow mask in different directions and then hit the associated phosphor points on.

The beam generation systems of such a tube and thus the electron beams generated by these systems are often arranged in such a way that the blue system is spaced vertically above the longitudinal axis of the tube lies, while the red and green systems are at a distance from the tube axis and in one Angular distance of 120 ° around the tube axis compared to the blue system offset on opposite ones Sides of the axis are arranged. The electron beams must therefore have different sections run through the deflection field, which is designed in combination with other devices so that a results in optimal coverage of the rays with the fluorescent points and during the beam deflection a convergence of the three rays is guaranteed at all points of the luminescent screen.

The initial convergence of the three electron beams in the center of the fluorescent screen is achieved by statically controlled magnetic devices. This can be achieved with either permanent magnets or electromagnets. Because of the angular spacing of the electron beams with respect to the longitudinal axis of the picture tube and the special properties of the field generated by the deflection coil arrangement, which must meet additional necessary conditions, the blue grid tends to be a means for correcting
Grid misregistration for a
Three-color television picture tube

Applicant:

Radio Corporation of America,

New York, N.Y. (V. St. A.)

Representative:

Dr.-Ing. E. Sommerfeld, patent attorney,

8000 Munich 23, Dunantstr. 6th

Named as inventor:
Maximilian John Obert,
John McDaniel Ammermann,
Indianapolis, Ind. (V. St. A.)

Claimed priority:

V. St. v. America July 15, 1964 (382 786)

to become wider than the other two grids, so that there are beam misregistrations at the side edges of the image appear. For color television picture tubes with a deflection angle that does not significantly exceed 70 ° it is possible by means of the deflection fields and by static and dynamic convergence arrangements achieve an acceptable coverage or coincidence of all three grids.

At larger deflection angles, e.g. B. 90 ° or more, the arrangements used so far are not enough more about an acceptable beam convergence and grid coverage at the side edges of the image surface to reach. The deflection coil arrangement can be redesigned to avoid such convergence errors or to correct grid registration errors, but then mostly other convergence errors occur that are noticeable in other areas of the image. But this would be more disturb as errors that appear on the side areas of the image. Due to manufacturing tolerances the deflection coil arrangement can also slightly differ in the widths of the three grids.

Another possible solution is to move the blue beam horizontally or laterally Correct direction dynamically. However, this requires additional facilities and circuitry

809 619/365

3 4

arrangements for their feeding. The receiver will be red system 17 so that it is shown in FIG. 1 cannot be seen thereby more complicated and in the production and is.

more expensive to operate. It is therefore desirable that the con-outside of the tube 10 is at the transition of the

vergence of the three electron beams with the front neck 12 in the widening piston part U existing arrangements and possibly simple and 5 a deflection coil arrangement 18 mounted. The favorable ones to achieve additional facilities. The present invention relates to the mounting arrangement

The invention is intended to eliminate these difficulties for the deflection coil set, which will be described in more detail will. will practice. Immediately behind the deflection coils 18

The object of the present invention is to provide a beam convergence device 19, based on the disadvantages of the Stan- io described above. Further back on the neck 12 is located of the prior art and a device 20 for improving color purity Correction of grid misregistration for a unit and behind it a side magnet 21. The picture tube Specify three-color television picture tube, the very 10 and the additional devices mentioned are simpler and is inexpensive. so that a more detailed explanation is not necessary.

This object is achieved with a device of FIG. 1 The three beam generating systems of the type shown in FIG is pivotally mounted, which is perpendicular to the relative position of the systems and which stands through them on the plane which the tube axis and generated rays are designated with B, R and G, which in one raster deflection direction with respect to the ao The blue electron beam B lies directly above the Tube axis offset electron beam contains. Longitudinal axis 22. The red and green electron

Further developments and advantageous refinements beam R or G are located below the axis of the invention are identified in the subclaims on opposite sides of this. That draws. Convergence device that forms part of the

The invention is illustrated below on the basis of a calculation by means of which a convergence of the three Typical embodiment in conjunction with rays causes at all points of the screen the drawing explained in more detail, it shows, contains pole pieces 23, which the individual beam

1 shows a side view of a partially open plan. The three-beam color television picture tube cut to the blue beam B and the arranged pole pieces 23 generate, for example, an external component 30 excitation by an excitation magnet 24 arranged outside the tube neck, 12 when the tube is operated.

F i g. Figure 2 is a cross-sectional view in a plane 2-2 field between them through which the blue beam is radial 1, is moved with respect to the axis 22. For the red one

Fig. 3 is a side view of part of the Fig. 3 and green rays R and G are corresponding PoI Figs. 1 and 2, a partially 35 pieces23 and magnets 24 provided, the red beam cut and fitted onto the neck of the tube and the green beam radially in direction of the tube deflection coil support axis and deflecting away from this axis so that wäh -

F i g. 4 shows a perspective view of a deflecting beam deflection at all points of the image coil adjustment arrangement; Screen a meeting of the three rays

Fig. 5 is a sectional view of the deflection coil holder 40 is guaranteed. tion in a level 5-5 of FIG. 3 and the through the fields between the pole pieces 23

Fig. 6, 7, 8 graphical representations of the effected radial corrective movements of the red Grids that appear on the screen of the FIGS. 1 and the green beam with respect to the axis 22 entbis 3 and hold both a vertical and a horizontal tube on the component in the following explanation of the execution. The radial corrective movement of the approximately example of the invention is referred to. blue ray, on the other hand, consists exclusively of

F i g. Figure 1 shows a three-beam shadow mask color of the vertical component of motion. To the picture tube It was to achieve the desired beam convergence with a relatively large expanding beam convergence the front part 11 and a relatively thin cylin- therefore required a horizontal or lateral throat throat 12. The piston is provided in front by a 50 control of the blue beam. Both Front panel 13 completed, on the back of devices that were previously in connection with color images Fluorescent screen 14 is arranged, the tube a relatively small deflection angle (z. B. 70 °) verVielzahl of triples of phosphor dots were turned, this horizontal control was done by corresponding electron beams of the blue beam during the beam scan are stimulable and then light three different 55 by a static control field. The Create colors, e.g. B. Red, Green and Blue. Behind the initial static convergence of the three rays The luminescent screen is a perforated mask 15, in the middle of the image field by permanent magnets which has a multitude of openings, which are set, functionally part of the conical of the phosphor dot triples aligned vergence magnetic structure 24, and by a are and together with other elements of the 60 additional permanent side magnet 21. It has Tube the three electron beams onto the belonging- however, it has been shown that it is with larger distractors Directs fluorescent dots. In the neck 12 of the picture angles, z. B. 90 ° or more, with this control tube 10 three electron beam generation directions are no longer possible, in the extreme systems, of which only the blue system is left and right of the image field, d. H. at 16 and the red system 17 are visible. The systems 65 of its borders, a perfect convergence of all deliver the three electron beams for the three beams during operation.

Stimulation of the screen 14. The green system lies. A satisfactory overlap of the red and

in practically the same horizontal plane as the green grid, tubes with large

5 6

Ren deflection angles by suitable dynamic projections 46, 47 which are slidable from the

Control of the convergence magnet devices 24, rear side slots 37 and 38 of the housing

can be recorded using vibrations suitable 25.

Achieve shape. This is due to the fact that the rear edge 42 of the bearing half-shell 39 is the one

red and green beam by means of the inner pole pieces 5 at the lower rear slot 36 of the housing 25

A horizontal recess 48 (FIG. 5) is provided corresponding to the pole pieces 23. The cone-

can give movement component. Such a frustum-shaped section 43 has an opening 49

horizontal dynamic correction by means of the pole (Fig. 3), which has a fork-shaped end portion 51 of a

pieces 23 is not possible with the blue beam arm 52 picks up. The arm 52 is shown in FIG. 4 ge

Lich, as explained above. One can show the solution in more detail. It extends in the arrangement

this problem an additional control device to the rear and is there with one to the outside

Provide with the necessary circuits, provided by reaching projection 53. The lead

the required lateral movement of the blue has lateral flanges 54 and is designed so

Electron beam as a function of deflection, so that it has the lower rear slot 36 of the housing

dynamic, is effected. In the following now 15 spans or includes 25, the flanges 54

Embodiment to be described, example of the invention on the inside of the housing end 29 (FIG. 5)

However, such additional, dynamic locations can be applied. A screw 55 is located in the projection 53

working side deflectors for the blue beam screwed into the inside of the indentation

omitted. 48 attacks and the height of the rear part of the

The embodiment of the invention is now allowed to set 20 bearing half-shell 39. The for on the basis of FIG. 3 to 5 described. The illustrated height adjustment arm 52 has two positioned Bracket for the deflection coil arrangement stood up ribs 56, which are on opposite- (deflection yoke) consists essentially of three moving the sides of a web 57 of the holder 39 Main parts. One of these parts is a hollow, sewing-can and securing arm 52 in a lateral direction cylindrical housing 25. Place the housing 25.

25 has an annular front end 26 with a die deflection coil assembly 58, in section of which Number of forward protrusions 27 one of the horizontal deflection coils 59 and a ferrite. These projections 27 engage on the back core 61 shown is from the bearing half funnel-like widening piston part 11 shell 39 and is on this on suitable, of the picture tube 10. 3 ° attached manner not shown (Fig. 3).

The second main part of the bracket for the Ab- Through the lower front projection 44 and Steering coil assembly consists of an annular rear lateral projections 46, 47 of the Ab-frame 28, of the steering coil holder 39 in the rear end 29 of the housing are clamping screws 62, 63 25 intervenes. The frame 28 is used to mount the or 64 screwed. These screws are used to Convergence coils, of which the blue convergence 35 fixing the bracket 39 and the deflection coil 24 is shown in dashed lines. The frame 28 assembly 58 in a desired location with respect to comprises the neck 12 of the picture tube 10 and is connected to the beam generating systems and the of these in sem by a number of electron beams generated towards the rear of the picture tube. if attached stretching fingers 31, which are loosened by means of one of the three clamping screws, the brace 32 comprising them is firmly pressed against neck 12 40 bracket 39 and the deflection carried thereby will. coil assembly 58 along the axis of the picture tube

In the front part of the housing 25 a lower one can be moved, whereby the various front

Slot 34 is formed, and two corresponding lateral jumps in the associated slots in the housing 25

Slots 35, 35 a are located on opposite slides. The clamping screws 62, 63, 64 are with

the sides of the picture tube (Fig. 5). In the rear part 45 approximately U-shaped brackets 65, 66 and 67 are provided,

of the housing 25 are a lower slot 36 and which rest on the outside of the housing 25,

two lateral slots 37, 38 are provided. All of these when the screws are tightened.

Slots are used to receive projections or the rear lateral projections 46, 47 are

Lugs, which on one of the other main parts of the somewhat narrower than the slots 37

Bracket are formed. 50 or 38. To a certain vertical movement of the

The third part of the bracket to allow for the deflecting projections in their slots, though coil assembly consists in an upwardly open the height of the rear end of the bracket with the help Bearing half-shell for the deflection coil assembly. of the arm 52 and the adjusting screw 55 are set The bearing half-shell 39 comprises a front and is. Those behind are also in the same way Edge 41 or 42, the approximately semicircular 55 borrowed front projections 45, 45 ″ somewhat narrower are. In the illustrated embodiment, the than the slots 35, 35 a, so that the front end of the front edge 41 a larger radius of curvature bracket can pivot when the height of the hinals the rear edge 42. The bearing half-shell comprises the lower part is set.

also a substantially frustoconical problem underlying the invention and Section 43 which connects the edges 41,42. The 60 its solution by means of the deflection lower described Edge 41 is coil holder with a lower projection 44 is in the following with reference to the provided, which in the longitudinal direction of the picture tube in FIG. 6, 7 and 8 explained. For this explanation, lower front slot 34 of the housing 25 slide assumed that the adjustment screw 55 from the can. The bearing half-shell is also provided with two protrusions 53 for height adjustment front lateral projections 45, 45a provided, 65 arm 52 (Fig. 3, 4 and 5) turned back so far which is in the front lateral slots 35 and 35 a, that the rear edge 52 of the bracket 39 on of the housing 25 are able to slide. The rear of the inside of the rear section 29 of the GeRand 42 of the bearing half-shell 39 has two lateral housings 25 and the rear end of the deflection

coil assembly its lowest position with respect to the If after the adjustment of the coverage of the

Tube neck and thus occupies the three rays. Fig. 6 shows a typical misregistration in dynamically operating magnetic convergence of the sides of the green, blue and red grids, as devices should point out that the blue is narrower than without dynamic convergence and without adjustment If the deflection coil holder is made to coincide according to the red and green grid of the invention, a coincidence can occur. The vertical center lines 68 of the three of all three grids are achieved by making the grid R, G and B coincide in the illustration with respect to the rear end of the deflection coil arrangement and intersect the tube axis. In Fig. 6 is lowers the three rays. The side edges of the blue grid by three vertical lines then move away from the picture frame, of which line 68 practically goes through the center of the field, while the sides of the red and green center of the front panel 13 of the screen tube go Approach the center of the image field while lines 69, 71 line the side edges of the

indicate the blue grid and on the left or right-hand red and green grid through the on the rays on the th side of the screen. Because of the dynamic convergence fields acting in FIG. The arrangement of the three beams shown in FIG. 2 is sufficient and that this is not the case with the blue grid with respect to the tube longitudinal axis 22 is to be expected, is possible, since there is no possibility for the blue ray the ability of a dynamic blue acting in a lateral direction, which is arranged directly above the tube axis System 16 supplies a grid that consists of horizontal correction. With the adjustable direction is centered with respect to the screen surface. 20 deflection coil support mechanisms are therefore This is also shown in FIG. 6. the deflection fields of the deflection coils to the side

Because of the position also shown in Fig. 2, the convergence correction of the blue beam is used, the red beam, which runs to the left of the tube axis 22 by the adjustable tilting of the deflection coils, the red grid is normally arranged around a horizontal axis, one of the blue grid to the right shifted, as in 25 all three grids to a relatively simple fig. 6 is shown. When the vertical middle and cheap way are achieved, as described above, the grid lines 68 were put together on the tube axis. If the lines 73, 74, which represent the lateral margins of dynamic fields for correcting horizontal ones of the red grid, are used on the left and right misregistration of the blue grid, then already existing ones will fall. At the edge of the image field shifted to the right with respect to the edges 69, 71 of the blue grid of the described embodiment of the invention. For reasons that do not speak for additional circuit arrangements, the edges 76, 77 for generating a lateral direction of the green raster are located to the left of the corresponding correction field for the blue beam or an edge 69, 71 of the blue raster. Modification of the flux distribution of the deflection coil

F i g. Fig. 7 shows the arrangement written by the three beams, by which other convergence errors occur Grid if the static and dynamic would be required.

Convergence, but not the support for the The amount by which the deflection coil assembly

Deflection coil assembly are adjusted. The center line, tilted or moved by the adjusting screw 55, of the three grids must fall back in the middle, is relatively small and pretty much the screen together. On the left and right 40 critical. In a color television receiver of the pray side of the image field, although the edges 73 fall signed type enables the adjustment of 76 and 74, 77 of the red and green raster together screw 55, for example, a movement of the Abmen, the edges of the blue rasters 69 and 71 Steering coil assembly by 1 mm in both directions, however, lie outside the edges of the other of the coaxial position with respect to the tube axis, both grids. The width Wg of the blue grid is 45. With this adjustment, the blue grid can be somewhat larger than the width W _RG of the corners by 1.65 to 1.9 mm and in one of the red and green grids. Distance of about 10.7 cm from the respective corners

The error shown in Fig. 7 will change by about 0.88 to 1.02 mm; the change corrected the present invention. As mentioned, should then take practically up to the horizontal center line the rear end of the deflection coil assembly 50 table down to zero.

initially in its lowest position with respect to the embodiment of the invention described

Tube neck and the three rays are located. Um is for the usual arrangement of the beam generating device in FIG. 7, where the blue system overlaps, the height adjustment screw 55 located on the tube axis is turned. Understandably, the invention is not limited to the rear end of the deflection coil arrangement 55, but can be lifted with respect to the tube neck. If it is more correct to use it for other beam arrangements, all three grids coincide, as in z. B. if one of the three systems, which is shown in a Fig. 8, so that all three grids have a mutual angular distance of 120 ° around the tube the same width W. It should be mentioned that the renachse are distributed, in the horizontal direction next to width W 'is slightly smaller than the width W _{B of} the 60 of the tube axis. In this case, the uncorrected blue grid and somewhat larger than the beam of the horizontal next to the tube axis would be the width W _{RG of} the coincident red and lying systems through the dynamic congreen grid, as shown in FIG. The vergence effecting pole pieces 23 only a lateral lifting of the rear end of the deflection coil arrangement experienced dynamic convergence, while a vernation thus causes that the sides of the blue 65 vertical convergence correction would not be possible. Ge raster approach the center of the image field, while the measure of the invention can then remove a dynamic side of the red and green raster from the image correction in the vertical direction achieved by the center of the field. the fact that the deflection coil arrangement in a horizontal

IO

zontal plane is tilted about a vertical axis. Since the main coordinates of a television picture are horizontal and run vertically, is absent in the electron beam which moves with respect to the tube axis in Direction of one of the coordinates is shifted, the possibility of a dynamic correction in direction the other coordinate. In order to effect this dynamic correction on the relevant beam, the deflection coil arrangement must therefore be adjustable by tilting or rotating.

In the described embodiment of the invention, the deflection coil arrangement was adjusted by means of arm 52 and screw 55 attached to the rear of the deflection coil assembly are arranged. However, the invention is not limited to this particular arrangement and location the adjustment arrangement limited. A corresponding adjusting screw or device with the same effect can also be arranged at the front end of the deflection coil assembly to avoid the deflection coil ao arrangement for setting the dynamic correction for the blue beam by a desired one To be able to increase or decrease the amount. There is of course a certain margin between the front end of the deflection coil assembly and the tubular piston that controls the relative movement between these elements allows. The special arrangement of arm and screw represents only one embodiment of the invention. Other equivalent arrangements to one of Hand adjustable arrangement can be used to adjust the deflection coil arrangement to effect the required dynamic convergence correction.

35

Claims (7)

Patent claims: 1. Device for correcting grid misregistration for a three-color television picture tube, in which three electron beams, which initially run approximately parallel to the tube axis and at equal angular distances from one another with respect to it, are grid-like in two directions by a deflection coil arrangement which is at least approximately coaxial to the tube axis and furthermore through an arrangement are each deflectable radially with respect to the tube axis for dynamic convergence and one of the electron beams is offset in the one raster deflection direction with respect to the tube axis, characterized in that the deflection coil arrangement (58) is pivotably mounted about an axis which is perpendicular to the plane which the tube axis (22) and the electron beam (B) offset in one raster deflection direction with respect to the tube axis. 2. Device according to claim 1, characterized in that the deflection coil arrangement (58) by means of an adjusting screw (55) or a device with the same effect around the said Axis is pivotable. 3. Device according to claim 2, characterized in that one on the tube (10,11,12) attached holder (25) is provided for the deflection coil assembly (58) and that the adjusting screw (55) is arranged between the holder and the deflection coil assembly so that the deflection coil assembly with respect to the Bracket is movable. 4. Device according to claim 3, characterized in that the deflection coil arrangement (58) is fitted into a bearing (39), which in the holder (55) is parallel to the tube axis slidably and rotatably mounted about the normal axis. 5. Device according to claim 4, characterized by devices (62, 63, 65, 66) for Determination of the bearing (39) of the deflection coil arrangement (58) with respect to the holder (25) during operation. 6. Device according to claim 4, characterized in that the adjusting device (55) between the bearing (39) of the deflection coil arrangement (58) and the holder (25) is arranged. 7. Device according to one of the preceding claims, wherein the grid is vertical and have a horizontal deflection direction and the one electron beam in a vertical direction Direction is offset with respect to the tube axis, characterized in that the deflection coil arrangement (58) is adjustable in a vertical plane about a horizontal axis. Considered publications:
"Proceedings of the IRE", 1951, October, pp. 1249-1263. 1 sheet of drawings 809 619/365 9.68 © Bundesdruckerei Berlin