FI73337B - FAERGBILDSPRESENTATIONSSYSTEM. - Google Patents

Description

1 73337 Color image display system

The present invention relates generally to color image display systems, and more particularly to an apparatus having a multi-jet color image tube including a deflection coil unit and a low aberration jet focusing lens to form a new self-converging display system capable of low storage energy performance without compromising high storage energy without jet.

Early use of perforated plate type multi-jet color picture tubes in color image display systems required dynamic convergence correction circuits to ensure the convergence of the jets swept across the image surface of the color picture tube at all points in the raster. Also later, as described, for example, in U.S. Patent No. 3,800,176 to Gross, et al., A self-cohesive display system was developed that eliminates the need for a dynamic convergence correction circuit. In the system described in the above-mentioned patent, Gross, et al., Three in-line electron beams are subjected to deflection fields containing inhomogeneities which provide negative horizontal isotropic astigmatism and positive vertical iso-tropical astigmatism in a manner consistent with -you.

In the original commercial solutions of the system described in said patent publication, Gross, et al., The center-to-center distance between adjacent jets in the deflection plane (S-distance) was kept less than 5.08 mm (i.e. less than 200 mils, i.e. 0.2 inches) to facilitate convergence requirements. This proximal distance between the jets imposes limitations on the diameters of the jet location apertures, which are arranged on the transverse elements of the focusing electrodes of the electron gun sources of the swept jets. The effective diameter of the focusing lens determined for each jet of the small diameters of these apertures is associated with the problem of jet point distortion due to the spherical afceration associated with the small diameter lenses.

Later, in commercial applications, 10 wider distances between the jets were used, which allowed the use of larger diameter apertures of the focusing electrode. This alleviated the problem of point distortion, but at the expense of making it more difficult to achieve convergence.

15 A later stage in the development of self-converging display systems, described, for example, in "Mini-Neck Color Picture Tube", E. Hamano, et al., Toshiba Review, March-April 1980, pages 23-26, uses a tube-deflection coil unit combination in which involves a relatively compact deflection coil unit, with the outer diameter of the neck of the color picture tube being significantly smaller (22.5 mm) than the outer diameters of the neck traditionally used until then (29.11 mm and 36.5 mml. In Hamano, et al., horizontal deflection reactive power savings Hamano, et al., however, states that a reduction in neck diameter leads to a reduction in neck diameter and improvements in deflection sensitivity of 20 to 30% (compared to traditional 29.11 mm neck systems). dimensions that make it more difficult to achieve a satisfactory swamp of focus performance and High-voltage stability (i.e., reliability with respect to arc formation).

The present invention relates to a color image display system using a tube / deflection coil unit 3,73337, in which deflection power savings, deflection sensitivity improvements and the deflection coil unit compactness compared to the corresponding features of the above-mentioned "mini-neck" system can be achieved without resorting to to reduce the diameter of the neck. The system according to the present invention uses a small S-spacing dimension of less than 5.08 mm, i.e. 200 mils, as in said "mini-neck" system. However, in contrast to the "mini-neck" system-10, in which the effective focusing lens diameter is limited to a dimension smaller than the distance between adjacent jets entering the lens as measured from the center to the center, a focusing electrode structure with an asymmetric main focusing lens is used. is significantly more than three times the distance between the jets measured from the center to the center.

The image display system according to the present invention is characterized by the features set forth in the characterizing part of the appended claim 20.

In the system of the present invention, which avoids the reduction in neck diameter associated with the "mini-neck" system, focusing voltage levels comparable to those traditionally used so far can be applied, without compromising on high voltage stability, a suitable connection between the focusing electrode structure and the inner walls. with sufficient space for the distance. At these voltage levels, the focusing performance is significantly better compared to what is easily achievable with the above-mentioned "mini-neck" system. Alternatively, part of said improvement in focusing performance may be to change the focus to facilitate operation at lower voltage levels to facilitate the requirements of the voltage source.

In an exemplary embodiment of the present invention, the tube / deflection coil assembly 4,73337 uses a tube having a conventional outer diameter of 29.11 mm. The handling problems associated with the more brittle 22.5 mm neck are avoided both during the fabrication of the tube and during the assembly of the image display system 5. The increase in emptying time associated with emptying the "mini-neck" tube is also avoided.

According to an exemplary embodiment of the present invention using a 90 ° deflection angle, a self-converging 19V image display is provided with a 29.11 mm neck tube having an S-distance dimension of less than 5.08 mm , and with an oak ring-type (horizontal deflection coils annular and vertical deflection coils saddle-shaped) compact deflection coil unit, the deflection coil-15 inner diameter of the horizontal deflection coils of the windows with a deviation of 30762 (i.e. less than 0.70 cm The requirement for the stored energy of the horizontal deflection windings of the compact 90 ° deflection coil unit, when the pipe operates at an extreme anode voltage of 25 kV, is as low as 1.85 mJ.

According to another exemplary embodiment of the present invention using a 110 ° deflection angle, a self-converging 19V image display is provided with a tube having the above neck and S-distance dimensions and a compact half-ring deflection coil unit having an inside diameter at the window jet outlet about 8.15 cm, or 3.21 inches (i.e., again less than 0.762 mm per 30 degrees of rotation angle). The stored energy requirement of the horizontal deflection windings of the compact 110 ° deflection coil unit, when the pipe operates at an extreme anode voltage of 25 kV, is as low as 3.5 mJ.

To evaluate the relative compactness of the deflection coil units in the above-described embodiments 5,73337, it should be noted that the exemplary value of the corresponding internal diameter of the 90 ° deflection coil unit previously widely used for the aforementioned wide S-distance tube types is 7.82 cm (3.08 inches). 5 In contrast, the 110 mm deflection coil unit widely used in connection with wide S-distance dimensions is 10.87 cm (4.28 inches) (both diameters being significantly larger than 0.762 mm per deflection angle).

10 In each of the exemplary embodiments described above, a high level of focusing performance is ensured by using a 29.11 mm neck focusing electrode structure, which is disclosed in U.S. Patent Application Ser. 201692, Hughes, et al., 15 general forms. In this construction, the main focusing electrodes at the jet output end of the electron gun apparatus each include a portion disposed transversely to the longitudinal axis of the tube neck and through which three circular apertures are pierced, each through which a different electron beam passes.

Each of said main focusing electrodes also includes a connecting portion extending longitudinally from said transverse portion and providing a common frame for all paths of said jets.

The respective longitudinally extending portions of said main focusing electrodes are placed side by side to define a common focusing lens for the jets. The main transverse main dimension of the common frame of the last focusing electrode is, for example, 17.65 mm (695 mils), while the main main transverse dimension of the last common interface of the previous focusing electrode is, for example, 18.16 mm (715 mils). These dimensions have benefited from a larger space of 29.11 mm (1145 mil) neck (compared to the above-mentioned "mini-neck" tube) to provide a focusing-35 lens with a major transverse dimension at least three and a half times larger than the gap between the apertures 6,73337. the dimension measured from the center of the distance to the center. The difference between the corresponding transverse dimensions controls the desired convergence of the jets from the electron gun device.

In an exemplary form of the electron gun apparatus of the system according to an embodiment of the present invention, the shape of the inner circumference of the last frame of the last focusing electrode is "Racetrack", as shown, for example, in Hughes, et al., Supra, while the shape of the inner frame of the last focusing electrode dog-bone ", as disclosed, for example, in U.S. Patent Application No. 282 228, pp. Greninger. In addition, the jet-forming region 15 of the electron gun apparatus is associated with a type of lens asymmetry that reduces the vertical dimension of the cross-section of each jet at the entrance of the main focusing lens relative to its horizontal dimension. This asymmetry is caused, for example, by the connection of a vertically-extending rectangular slit extending vertically to each circular opening of the first lattice (G1) of the electron gun assembly.

Appropriate selection of the dimensions of the "Racetrack" frame, the "dogbone" frame, and the G1 gratings achieves an acceptable point shape at both the center and edges of the display raster by optimizing the balance of astigmatism associated with these elements.

Included in the following drawings:

Figure 1 shows a diagram of a tube / deflection coil unit according to an embodiment of the present invention;

Figure 2 shows a front end view of the deflection coil unit of the device of Figure 1;

Figure 3 is a side view, partly in section, of the electron gun apparatus used in the neck portion of the image tube of the device 35 of Figure 1; 7 73337

Figures 4,5,6 and 7 are respective end views of the various elements of the electron gun apparatus of Figure 3;

Fig. 7a is a cross-sectional view of the electron gun element of Fig. 7 taken along line A-A 'of Fig. 7; Fig. 7b is a cross-sectional view of the electron gun element of Fig. 7 taken along line B-B "of Fig. 7;

Fig. 8 is a cross-sectional view of the cannon element of Fig. 4 taken along line C-C "of Fig. 4;

Figure 9 is a cross-sectional view-10 of the cannon element of Figure 5 taken along line D-D 'of Figure 5;

Figure 10 is a cross-sectional view of the cannon element of Figure 6 taken along line E-E 'of Figure 6;

Fig. 11 shows an outline of a picture tube funnel suitable for use in an embodiment of the present invention using a 90 ° deflection angle;

Fig. 12 shows an outline of a picture tube funnel suitable for an embodiment of the present invention using a deflection angle of 110 °;

Fig. 13 schematically shows a modification diagram of the electron-20 cannon apparatus of Fig. 3;

Figures 14a and 14b show graphically the inhomogeneity functions preferably associated with the deflection coil unit of Figure 2.

Figure 1 schematically illustrates a picture tube / deflection coil assembly of a color image display system in accordance with the principles of the present invention. The color image tube 11 includes a emptied shell having a funnel portion 11F (partially shown) connecting the cylindrical neck portion IIN (including in-line electron gun hardware) to a substantially rectangular image surface portion including a display surface (not shown due to the size of the drawing). The part connecting the pipe neck part (IIN) and the funnel part (11F) is the collar 17 of the deflection coil unit 13.

The deflection coil unit 13 includes vertical deflection-35 windings, 13V, which are annularly wound around a core 15 of magnetized material surrounding the remote ___ -. 17 ^ 8 73337 lusi 17 (consisting of an insulating material). The deflection coil unit further includes horizontal deflection coils 13H, which are covered in Fig. 1. However, as shown in the front end of the deflection coil unit 13 5 not installed, the horizontal deflection coils 13H are wound in a saddle shape with active longitudinally extending conductors lining the inner collar 17. The front end turns of the windings 13H are turned up and placed in the front edge portion 17F of the collar 17, the rear end turns 10 (not shown in Figures 1 or 2) being similarly mounted on the rear edge portion 17R of the collar 17.

Figure 1 shows dimensional relationships suitable for an embodiment of the present invention. The compactness of the deflection coil unit formed by the windings 15 13H and 13V can be determined by a front inner diameter "i" of less than 0.762 mm (30 ml) per degree (relative to the deflection angle provided by the deflection coil unit). As shown in Figure 2, this diameter is measured from the front end of the active conductors of the saddle windings 13H (i.e., from the jet outlet end of the windows formed by these windings). The outer diameter "o" of the neck portion IIN of the color image tube 11 is shown to be a conventional 29.11 mm (i.e., 1145 mil). The electrostatic jet focusing lens 18 formed between the electrodes of the electron gun apparatus placed on the neck 13 (and denoted by the dashed lens symbol) is shown to have a transverse dimension "f" in the horizontal direction (i.e. in the horizontal plane defined by the three jet axes R, 30 G and B), which is more than three and a half times greater than the distance "g" between adjacent axes at the inlet to the lens, the latter dimension being. for example 5.08 mm (200 mils).

Fig. 3 is a side view, partly in section, of an electron gun apparatus of the type of Example 35 suitable for use in the neck portion IIN of the color image tube 11 of Fig. 1.

The electrodes of the electron gun apparatus of Figure 3 include three cathodes 21 (one of which is shown in the side view of Figure 3), a control grating 23 (G1), a shield grating 25 (G2), a first acceleration and focusing electrode 27 (G3) and a second acceleration and focusing electrode 29 (G4). The cannon elements are framed by a pair of glass support rods 33a and 33b, which are placed parallel to each other in parallel and between which the different electrodes are suspended. 10 Each of the cathodes 21 is directed at the electrodes

With respect to the respective openings in G1, G2, G3 and G4 to allow the passage of electrons emitted from the cathodes to the surface of the picture tube. Electrons emitted from the cathodes are formed by three electron beams 15 by means of electrostatic jet-forming lenses 15 formed between opposite apertured regions of the G1 and G2 electrodes 23, 25, which electrodes are maintained at different DC potentials (e.g. 0 volts and 1100 volts, respectively). Focusing of the jets on the image surface is performed primarily by an electrostatic main focusing lens (18 in Fig. 1) formed between adjacent areas (27a, 29a) of the G3 and G4 electrodes. For example, the G3 electrode is held at a potential (e.g., +2500 volts) that is 26% of the potential (e.g., +25 kilovolts) applied to the G4 electrode.

The G3 electrode 27 consists of two cup-shaped elements 27a and 27b, with their flanged open ends facing each other. Fig. 4 shows a front view of the front element 27a 30a, and a cross-sectional view (along the line C-C'in Fig. 4) is shown in Fig. 8. A rear end view of the rear element 27b is shown in Fig. 6, and a cross-sectional view thereof (along the line EE in Fig. 6). ") is shown in Figure 10.

The G4 electrode 29 comprises a cup-shaped element 29a, ίο 73337 having a flanged open end at its ends with a closed end provided with an opening in the electrostatic shield cup 29b. The end view of the element 29a is shown in Figure 5 and its cross-sectional view is shown in Figure 9 (along line D-D "of Figure 5).

Three in-line openings 44 are formed in the transverse portion 40 of the element 27a of the G3, which portion is located at the bottom of the recess at the closed front end of the element. The walls 42 of the recess, which define 10 common frames for the three jets coming from the respective openings 44, have a semicircular contour on each side, while in the intermediate part the contours run straight and parallel, thus forming a "racetrack" shape in the end view of Figure 4. The maximum horizontal inside dimension of the G3 frame is located in the plane of the shower axes and is denoted by "f ^" in Figure 4. The maximum vertical dimension of the G3 frame is determined by the distance from straight, parallel wall portions and is denoted by "^ 2" in Figure 4. Vertical is equal to 20 location.

Three in-line openings 54 are also formed in the transverse portion 50 of the G4 element 29a, which portion is located at the bottom of the recess at the closed rear end of the element. The walls of the recess, which define 25 common frames for the three jets arriving at the G4 electrode, are straight and parallel in the central region. However, the outlines on each side form a semicircle with a larger arc diameter greater than the distance between the parallel walls in the central region 30, resulting in a "dogbone" shape in the end view of Figure 5.

As a result of this shape, the vertical dimension (f ^) of the G4 frame at the middle aperture axis position is smaller than the vertical dimensions of the G4 frame at the corresponding outer aperture axis positions. The maximum horizontal inner dimension 35 of the G4 frame is located in the plane of the jet shafts and is denoted by "f 73" in Fig. 5. The maximum vertical dimension of the G4 junction corresponds to the diameter associated with the arcs of the end regions and is denoted by "f ^" in Fig. 5.

The maximum outer widths of the G3 and G4 electrodes in the respective "Racetrack" and "dogbone" regions are the same and are denoted by "f" in Figures 8 and 9. The diameters of the apertures 44 and 54 are also the same and denoted by "d". "in Figures 8 and 9. The depths of the recesses of the electrodes G3 and G4 (r in Figures 8 and 9) are also equal. The depth of the opening G3 (a ^ in Figure 8) and the depth of the opening G4 (a2 in Figure 9) are different. Example values for dimensions d, f ^, f2, ^ 4 '^ 5' fg »r, a ^ and a2 are as follows: d = 4.064 mm (160 mils); = 18.16 mm (715 mils); = 8,000 mm (315 mils); ) = 17.65 mm (695 mils) = 7.240 mm (285 mils) = 6.86 mm (270 mils) f = 22.22 mm (875 mils) r = 2.92 mm

O

(115 mils); α δ = 0.86 mm (34 mils); and α2 = 1.14 mm (45 mils). The example dimension for the distance from the center to the center measured between adjacent apertures at each focusing electrode is, as shown in connection with Figure 1, equal to 5.08 mm (200 mils). Exemplary shaft lengths 27a and 29a are 12.45 mm (490 mils) and 3.05 mm (120 mils), respectively, while the exemplary G3-G4 distance of Figure 3 for the apparatus 01 »1.27 mm (50 mils) in Figure 3 is .

The main focusing lens formed between the elements 27a and 29a acts primarily as a single large lens intersected by all three electron beam paths 30 and whose equipotential lines are relatively gently curved in the areas where the jet paths intersect, extending continuously between opposite recesses. In contrast, in prior art cannons lacking such a recess, the main 12 733 37 focusing effect is provided by relatively sharply curved strong equipotential lines centered on each of the non-recessed aperture regions of the focusing electrodes. In the exemplary arrangement of elements 5a 27a and 29a, the relatively sharply curved equipotential lines in the aperture areas play only a minor role in determining the quality of focusing performance (which is better determined primarily by the size of the large lens associated with the recess walls).

10 As a result, a small dimension of the distance between the jets (such as the previously mentioned value of 5.08 mm) can be used despite the constraint on the aperture diameter, and it can be assured that the level of undesired ball aberrations is relatively independent of the aperture diameter. the dimensions of the large lens determined by the walls of the recess are decisive. Under these conditions, the diameter of the neck becomes a limiting factor for focusing performance. Using the above exemplary dimension values in the iron focusing system of the present invention, excellent focusing performance can be achieved with external dimensions of the focusing electrodes (e.g., f ^) that can be easily fitted within a neck of conventional diameter (29.11 mm, 1145 mil) allowing distances to the shell. inner-25 wall as well as good high voltage stability performance (even in the worst possible glass tolerance condition). On the other hand, the focus electrode-30 structure according to these exemplary dimensions cannot be fitted to the neck of the "mini-neck" tube described in Hamano, et al., Supra.

The convergence property of the electrostatic jet head focusing lens 18 is related to the depth of the element, which, as described above, has a "Racetrack" shape on the circumferential contour. The asymmetry between the horizontal and vertical directions of this shape results in an astigmatic effect: the greater convergence of the vertically separated rays of the electron beam passing through the G3 electrode-13,73337 transverse recess than its horizontally separated rays. If the adjacent recess of the G4 electrode has a similar "Racetrack" contour, the diverging side of the main focusing lens 18 also has a compensating type astigmatic effect. Such a compensatory effect would be inappropriate to prevent the existence of net astigmatism. This could prevent the desired shape of the dot 10 from being achieved on the display surface.

One solution to achieve the desired additional astigmatism compensation is, as described in the aforementioned application, Hughes, et al., To use a gap formed by a pair of horizontal strips 15 in the openings of the transverse plate at the boundary of the elements 29a and 29b.

Another solution to achieve the desired additional astigmatism compensation is, as described in the above-mentioned application, to modify the contour of the walls of the recess in the Greninger, G4 electrode-20 to a "dogbone" shape. To this end, the reduction in the vertical dimension associated with the center region of the "dog-bone" contour is selected to either achieve substantially full compensation for astigmatism in the diverging portion of the main focusing lens itself or to complement the G4 gap compensating effect of the type described above. Exemplary dimensional choices for that solution are presented in the aforementioned Greninger application.

A different solution to the astigmatism compensation problem is used here, in which the compensating effect of the "dogbone" design of the contour walls of the G4 recess is combined with the compensating effect obtained by providing a suitable asymmetry to the jet-forming lenses defining the G1 and G2 electrodes (23, 25).

14 733 37 In order to evaluate the nature of the latter compensating effect, it is appropriate to consider now the structure of the G1 electrode 23, the end view of which is best shown in Fig. 7 and the related cross-sectional views shown in Figs. 7a and 7b.

5 In the central part of the electrode 23, three circular openings 64 (diameter d 1) are pierced, each opening communicating with a recess 66 on the rear surface of the electrode 23 and a recess 68 on the front surface of the electrode 23. Each rear surface recess 66 has circular walls at the contour 10, the diameter "k" of the recess being large enough to receive the front end of the cathode 21 (drawn in dotted lines in Figure 7b) at a distance from the walls of the recess. Each front surface recess 68 has a rectangular slot-shaped contour, the vertical dimension "v" of the slot being significantly larger than the horizontal dimension "h" of the slot. The center-to-center distance (g) between adjacent apertures 64 is the same as the apertures of the aforementioned electrodes G3 and G4. Exemplary values G1 for the other dimensions of electrode 23 are as follows: d 1 = 0.615 mm (25 mils); k = 3.075 mm (125 mils); h = 0.711 mm (28 mils); v = 2.134 mm (84 mils); depth of aperture 64 (α 2) = 0.102 mm (4 ml); depth of gap 68 (α) = 0.2C3 mm (8 mils); depth (a ,.) of recess 66 = 0.457 mm (18 mils).

When cathode 21 and G2 electrode 25 are assembled, the example value for ka-25 for the distance between Tod 21 and the bottom of the recess 66 is 0.152 mm (6 mils), while the example value for distance G1-G2 is 0.178 mm (7 mils).

In the assembly situation of Figure 3, each of the three circular apertures of the G2 electrode 25 is aligned with one of the apertures 64 of the G1 electrode 30. The presence of each intermediate gap 68 creates an asymmetry on the converging side of each lens forming the jet G1-G2. As a result, the intersection of the vertically spaced rays of each jet is spaced farther along the path of the jet 35 than the intersection of the horizontally spaced radii of the jet. As a result, the horizontal dimension of the cross-section of each jet entering the main focusing lens is larger than its vertical dimension. This "predistortion" of the cross-sectional shape of the jet 5 is of the type that tends to compensate for the point distortion effect of the astigmatism of the main focusing lens.

One of the benefits of using the "predistortion" of jets entering the main focusing lens described above is the increased uniformity of focusing quality in the vertical and horizontal dimensions. The asymmetry of the main focusing lens is such that its vertical dimensions in the lens areas intersected by the jet paths, although significantly larger than the diameter of the apertures of the focusing-15 electrodes (which limited the size of the lens to smaller in those areas. Thus, in terms of the vertically spaced radii of each jet, the lens is smaller than in terms of the horizontally spaced radii of the jet. The "predistortion" described above limits the vertical propagation of each jet during the passage of the main focusing lens so that the difference between the vertical boundaries of a suitably centered jet passing through a smaller, inferior vertical lens is smaller than that of a larger, better quality horizontal jet.

30 Another advantage obtained by using the above description

"pre-distortion" of jets entering the main focusing lens is to avoid or reduce vertical oscillation problems at the top and bottom of the grid due to undesired vertical deviation of the entry points of the jets 35 entering the main focusing lens in response to annular vertical deviations.

ie 73 3 3 7 to the flange field behind the deflection coil unit L3. When, as will be described later, an attempt is made to provide the jets with a certain magnetic protection against this mitigation field, in particular for the low speed areas of the jet paths 5, the following areas of the pathways are substantially unprotected against this mitigation field. Limiting the vertical propagation of each jet through the main focusing lens during passage described above reduces the likelihood that the entry point deviation caused by the flange field 10 would push the boundary rays out of the relatively non-aberrant lens areas.

A further advantage obtained by using the "pre-15 distortion" of the jets entering the main focusing lens described above is the reduction of the detrimental effects on the raster side with respect to the point shapes of the horizontal main deflection field provided by the saddle windings 13H. In order to produce the desired self-converging effects required by the deflection coil unit 13, the horizontal deflection field 20 is strongly padded over a substantial portion of the axial longitudinal direction of the deflection area of the jet. A detrimental consequence of the inhomogeneities of the horizontal deflection field is the tendency of each jet to be vertically spaced apart on the ras-25 side. When using the "pre-distortion" described above, the vertical dimension of each jet as the jet passes through the deflection area becomes sufficiently reduced so that the overfocusing phenomena on the raster side are reduced to a tolerable level.

In describing an alternative approach to achieving the above "predistortion" of jets, reference may be made to U.S. Patent No. 4,234,814 to Chen, et al. The structure described in Chen, et al. Has a horizontally long 35 rectangular slit recess in the rear surface of the G2 electrode in the same line and connection with each circular opening of the G2 electrode. Thus, in the arrangement disclosed in that publication, the contraction of the vertical dimension of each jet passing through the main focusing lens relative to its horizontal dimension is achieved by creating an asymmetry with the diverging portion of the lens forming each jet. With the electron gun system described above, in which asymmetry was provided to the G1 electrode, it has been found to achieve a beneficial improvement in focusing depth in the vertical direction. The achieved focusing depth is such that the focusing voltage control potentiometer normally present in the display system can be used to change the exact value of the focusing voltage (applied to G3 electrode 27) in a suitable adjustment range to optimize focusing horizontally without the need for significant focus distortion.

As previously mentioned, it is desirable to protect the low velocity areas 20 of the respective jet paths from the backward deflection fields of the deflection coil unit. For this purpose, a cup-shaped magnetic shield 31 G3 is fitted to the rear element 27b of the electrode 27 and fixed thereto at its closed end (e.g. by welding) end-to-end with the closed end of the element 27b (as shown in the assembly drawing of Fig. 3). As shown in Figures 6 and 10, three in-line openings 28 are pierced at the closed end of the cup-shaped element 27b, the walls of which have a circular contour.

At the closed end of the magnetic shield 31 are similarly pierced three in-line openings 32 having a circular contour on the walls, which openings are aligned and in communication with the openings 28 when the cover 31 is fitted.

35 In the assembly of Figure 3, the apertures 28 are in a straight line but axially separated from the apertures 26 of the G2 electrode 25. Exemplary dimensions of this part of the assembly are: diameter of the aperture 26 = 0.615 mm (25 mils); depth of aperture 26 = 0.508 mm (20 mils); diameter of orifice 28 == 5 1.524 mm (60 mils); depth of aperture 28 = 0.254 mm (10 mils); diameter of orifice 32 = 2.54 mm (100 mils); and depth of aperture 32 = 0.254 mm (10 mils); the axial distance between the orifices 26 and 28 in a straight line is 0.838 mm (33 mils), and the distance between the adjacent apertures 10 of each of the three apertures, measured from center to center, is equal to the previously mentioned "g" value of 5.08 mm (200 mils). The example value of the axial length of the magnetic sheath 31 is 5.38 mm (212 mils), compared to the example values of the axial lengths 15 of the G3 elements 27b and 27a of 13.335 mm (525 mils) and 12.45 mm (490 mils). This sheath length (less than a quarter of the total length of the G3 electrode) represents an acceptable compromise between conflicting desires to protect the jet paths in the pre-focus area 20 and to avoid field distortion that interferes with angular convergence. For example, the protective shell 31 is formed of a magnetic material (e.g., a nickel-iron alloy in which 52% is nickel and 48% is iron) having a high permeability to the permeability of the material used in the focusing electrode elements (e.g., stainless steel).

The front element 29b of the G4 electrode 29 includes a plurality of contact springs 30 on its front circumference to make contact with the conventional graphitized inner surface of the picture tube to supply an extreme anode voltage (e.g., 25 kV) to the G4 electrode. The closed end of the cup-shaped element 29b includes three in-line apertures (not shown) in line, center-to-center distance of 5.08 mm (200 mils) according to the example, 35 for passing through corresponding jets leaving the 19,73337 main focusing lens. High permeability magnetic members attached to the inner surface of the closed end of the element 29b in the vicinity of the opening are preferably used for Koma correction purposes, as described, for example, in U.S. Patent No. 3,772,554 to Hughes.

The distribution of the operating voltages to the other electrodes (cathode, G1, G2 and G3) in the configuration of Figure 3 is performed through the base of the picture tube through conventional conductor structures (not shown).

The main focusing lens formed between the electrodes G3 and G4 of the assembly of Figure 3 has a net converging effect on the three jets passing through the lens, the jets deviating from the lens in a converging manner. The relative magnitudes of the horizontal dimensions of the adjacent frames of the elements 15a and 29a affect the magnitude of the converging effect. The increase in the converging effect is related to the dimensional ratio that favors the width of the G4 frame, and the decrease in the converging effect is related to the 20 dimensional ratio that favors the width of the G3 frame.

In an embodiment where the dimensions are as described above and a reduction in the converging effect is desired, a width ratio of 715/695 frames of G3-G4 is found to be suitable.

When using the display system of Figure 1, an additional neck-surrounding device (not shown) can be conventionally used to adjust the convergence of the jets at the center of the raster (i.e., static convergence) to the optimum mode. Such an apparatus may be, by way of example, an adjustable magnetic ring, the type of which is generally described in U.S. Patent No. 3,725,831 to Barbin, or, as another example, the type of shield, generally described in U.S. Patent No. 4,162,470 to Smith.

Fig. 13 schematically shows a modification of the electronic cannon apparatus of Fig. 3, which can alternatively be used in the apparatus of Fig. 1. According to the modification, a pair of additional focusing electrodes (27 ", 29") are placed between the protective grating (25 ') and the main acceleration and 5 focusing electrodes (21', 29 "). The main focusing lens is defined between these last electrodes (27 ', 29'). , which in this case comprise G5 and G6 electrodes. The additional transverse focusing electrode (G3 electrode 27 ") mounted transversely is energized with a sa voltage (e.g. + 8000V) than the G5 electrode 27 ', while the second additional focusing electrode (G4 electrode 29") is energized to the same voltage (e.g. +25 dV) as the G6 electrode 29. As in the embodiment of Figure 3, the private jets are formed (from the electrodes emitted by the respective cathodes 21 ') by means of respective jet forming lenses provided by the control grille (G1 electrode 23') and the protective grating (G2 electrode 25 ').

In an alternative embodiment, the G5 20 and G6 electrodes (27 "and 29") are, for example, the general shape that the G3 and G4 electrodes (27, 29) of the apparatus of Figure 3 are assumed to be, and the "Racetrack" and "dogbone" frames placed side by side. shape and dimensions as previously described, the distance from the center to the center of the recessed apertures at the bottom, as measured above, being 5.08 mm (200 mils) .The "predistortion" of jets of the type previously described is achieved by the asymmetry of the respective jet-forming lenses. For example, with the structural shapes of the G1 and G2 electrodes (23 ', 25') described in the aforementioned patent publication Chen, et al., Wherein the horizontally oriented rectangular slits join the rear surface G1 and G2 of the G2 electrode (23 ') with circular openings. between groups of three openings formed by the distance between the openings from the center tl 2i 733 Measured at 37 centers, the above is 5.08 mm (200 mils). Additional focusing electrodes (27 "·, 29") interposed, for example formed of cup-shaped elements with additional in-line groups of three circular apertures lined up in the bottoms (distance from center to center mentioned above) , provide symmetrical lenses G3-G4 and G4-G5, the net effect of which is a symmetrical reduction in the cross-sectional dimensions of the jet passing through the main focusing lens and the next deflection range. the reduction is achieved at the expense of providing a larger center size than that achieved with the simpler two-potential focusing system of Figure 3. Using the arrangement of Figure 13, protection of the low velocity jet path area previously discussed in the past. in connection with the ditch shell 31, is obtained, for example, by forming the G3 electrode (27 ') from a high permeability material.

To increase the sensitivity of the deflection coil unit of the system of Figure 1, it is desirable that the contour of the conical portion of the funnel portion (11F) of the tube shell 25 be selected so as to allow the active conductors of the deflection coil deflection coil 13H to be located so close to the outer jet path. angle) as much as possible while avoiding shadow (collision of the deflected jet with the inside of the funnel). Figure 11 shows a contour of a funnel suitable for an embodiment of the system of Figure 1 using a 90 ° deflection angle. The mathematical formula indicating the outline shown is as follows: X = CO + 35 Cl (Z) + C2 (Z2) + C3 (Z3) + C4 (Z4) + C5 (Z5) + C6 (Z6) + 7 22 733 37 C7 (Z); where X is the radius of the cone measured from the longitudinal axis of the tube towards the outer surface of the shell, expressed in millimeters, Z is the distance in millimeters along the axis A, in the direction of the display surface, Z = 0 at a plane cut point 1.27 mm forward of the neck / funnel joint; where CO = 15.10490590, Cl = - 0.1582240210, C2 = 0.01162553080, C3 = 8.880522990 · 10-4, C4 = -3.877228960. 10 ~ 5, C5 = 7.249226520. 10_7, C6 = -6.723851420. 10 ~ 9; and 10 C7 = 2.482776160. With 10 expressions valid for Z. values of 9.35 mm ... 52.0 mm.

Figure 12 shows a contour of a funnel suitable for an embodiment of the system of Figure 1 using a 110 ° deflection angle. The mathematical formula indicating the outline shown is as follows: X = CO + C1 (Z) + C2 (Z2) + C3 (Z3) + C4 (Z4) + C5 (Z5), where X is the radius of the cone measured from the longitudinal axis A "expressed in millimeters on the outer surface of the shell; Z is the distance in millimeters along the axis A 'in the direction of the display surface 20, the plane Z = O intersects at a point on the axis 1.27 mm forward of the neck funnel joint line; where CO 14.5840702, Cl = 0.312534174, C2 = 0, 0242187585, Cl = -6.99740898.10_4, C4 = 1.64032142.10 ~ 5, C5 = -7 1.17802606.10, the expression being valid for Z values of 25 1.53 mm ... 50.0 mm .

For example, in the embodiment of the system of Figure 1, with a deflection angle of 110 °, 19V diagonal, the throat of the deflection coil unit collar 17 is outlined such that the active conductors of the windings 13H may be closely adjacent to the outer portions of the shell portions 11F and IIN. 'when the deflection coil unit is in its foremost position. For example, the outline of the hopper of Figure 12 allows a deflection coil unit of that length (y-y ") to be retracted (5-6 mm 35 to adjust color purity) from its more advanced position n 23 73337 without causing a jet to collide with a corner of the shell.

Fig. 14a shows a general form of the H2 non-homogeneity function required by the horizontal deflection field required by the deflection coil unit of Fig. 2 to achieve a self-converging result in the 110 ° embodiment of the system of Fig. 1, with a solid line curve HH2, abscissa showing position along pipe length The position of the 12 plane Z = 0 is shown for position comparison purposes), the ordinate showing the degree of deviation of the field homogeneity. Figure 14a curve HH ^ upward offset of 0 axis (the direction of arrow P) shows a "cushion-like" field epähomoheeni-15 concentration whereas curve downward offset of 0 axis (the direction of arrow B) shows a "barrel-shaped" field inhomogeneity. The dotted curve HHg, drawn with respect to the same position abscissa, shows the function of the horizontal deflection field Hg to show a relative field strength distribution along the axis of the tube. The positive part of the curve HH2 indicates the location of the region of the strong pad-shaped field, which has been previously treated as the cause of point shape problems on the raster side.

Fig. 14b shows the general form of the H2 inhomogeneity function required by the vertical deflection field corresponding to the horizontal deflection field of Fig. 14a by means of the curve VH2 to achieve self-converging results, the abscissa and ordinate being as in Fig. 14a. The corresponding dotted curve VHg, expressing the vertical deflection-30 as a function of the field Hg, shows the relative field strength distribution along the axis of the tube. The far left part of the curve shows the crossing of the vertical deflection field at the rear of the annular windings 13V, as described above in connection with the advantages 35 of "pre-distortion" of the jet.

24 73337! i.

As can be seen, for example, when comparing the curves of Figure 14b to the contour of Figure 12, the main deflection operation of the system of Figure 1 occurs in an area where a suitable funnel contour allows the deflection coil unit conductors to be brought close to the outer jet paths.

The absence of a reduction in neck size associated with the "Minineck" system thus appears to play little role in achieving deflection performance. On the other hand, the absence of such a reduction makes it easy to obtain focusing lens dimensions that were impractical in a "mini-neck" tube, but which guarantee a high focusing quality without compromising on high-voltage stability performance.

In Fig. 12, the transverse planes c and c "indicate the position of the front and rear ends of the core 15, respectively, to 110 °, as described above, in the embodiment 19V of the system of Fig. 1. As shown, the axial distance between the front and rear ends of the horizontal conductors 13H y ') is significantly (e.g. 1.4 to 20 times) greater than the axial distance (c-c') between the front and rear ends of the core 15, more than half (e.g. 62.5%) of the extra conductor length is located on the back of the core 15. for cy, yy "and y'-c 'plane distances are about 7.62 mm (300 mils), 5.08 cm (2000 mils) and 12.7 mm (500 mils), respectively.

The use of a feature that provides a significant backward extension of the active conductors of the horizontal windings to the other side of the posterior end of the core helps to reduce the system's stored energy requirement (i.e., 2 30 h IjjLjj) and facilitates rearward displacement of the horizontal deviation center to a substantially vertical location. The limitations of this backward thrust of the horizontal windings are due to the free space requirements of the neck under the desired deflection coil retraction conditions, and the effect of achieving satisfactory convergence at raster angles. The relative position and axial length ratio of the windings 13H and the core 15 shown in Figure 12 represent an acceptable compromise between conflicting requirements, on the one hand increasing deflection efficiency and on the other hand achieving acceptable angular convergence performance and a suitable retraction range 10. As can be seen by comparing the respective curves HHq and VH1 in Figures 14a and 14b, the relative positions shown in Figure 12 for the coils 13H and core 15 preferably result in a substantially similar axial location of the respective peak-15 trees of the field strength distribution functions HHq and VHq HHq and VHq.

Claims (20)

A color display system comprising a color display tube which includes an evacuated housing including a display portion enclosing a display screen, a cylindrical neck portion, and a funnel portion connecting the display portion to the neck portion, and an electron gun assembly mounted within the neck portion in-line electron beams, a deflection yoke assembly (13) that circles adjacent segments of the neck (11N) and funnel (11F) portions for generating deflection fields that allow recording of grids on the screen with substantial convergence of the the beams throughout the presentation, establishing a given deflection angle between beam paths terminating at diagonally opposite raster corners, a yoke assembly including horizontal deflection winding (13H) with saddle configuration limiting respective window deflections and vertical deflecting winding (13w), respectively; for the rays within a region encircled by the housing, characterized in that it comprises a cannon assembly which includes a first and second main focusing electrode (27, 29. at the beam output end of the cannon assembly, which electrodes are poured at different potentials, each of said heads 25 vudofocusing electrodes include a portion (40, 50) disposed in the transverse direction with respect to the longitudinal axis of the neck and having a wooden group of in-line openings (44, 54) through each of which each of said beams passes, and a adjacent portion (42, 52) extending in the longitudinal direction therefrom and forming a common enclosure for the webs of all said beams, the respective adjacent portions of the electrodes being adjacent to each other and thereby forming a common main focusing lens between them (18) for the beams, from which the beam paths deviate in a coherent manner, that the distance (g) from center to center between adjacent apertures of each of the three groups n is such that the distance from center to center of adjacent beams among the beams is limited to less than 5.08 mm (200 miles) in transverse plane occupied by the deflection center, that the adjacent portions (27a, 29a) establishes a head value dimension (f) for the main focusing lens with substantially more than three times the distance from the center to the center between adjacent apertures, and that the diameter (0) of the neck portion (IIN) is large enough for the inside of the neck portion to be located on the distance from the exteriors of the adjacent enclosures and the inner diameter (i) of the compact yoke assembly (13) at the radius outlet end of the window is a total of less than 0.762 mm (30 mil) per degree of deflection angle. 2. A system according to claim 1, characterized in that the maximum transverse dimension (f2) of the main focusing lens (18) in a direction perpendicular to the main transverse dimension (f f) is smaller than the main transverse dimension but greater than the distance from the middle to the middle. openings. 3. A system according to claim 1 or 2, characterized in that the electron gun assembly includes beam forming means (23, 25) for bringing the cross-section of each beam at the input of the main focusing lens in the direction of the main value dimension of the main focusing lens. exhibit a maximum dimension greater than its maximum dimension in a direction perpendicular to the principal transverse direction. System according to claim 3, characterized in that the beam forming means include a three group of in-line cathodes (21), a first grid (23) disposed adjacent to the in-line cathodes and having a wooden group. of circular apertures (64) each aligned with a different cathode of the cathodes, a second lattice (25) disposed between the first lattice and the main focusing line and provided with a wooden group circular apertures which are aligned with each different aperture among the apertures of the first lattice, the lattices being held at different potentials (0.1100V) and between them forming beam-forming lenses for electrons emitted by the cathodes, and a slotted member (68) assigned to one of the grilles so that a substantially rectangular slit is inserted between each circular opening of the second grating and the respective aligned opening of the first grating. 5. A system according to claim 4, characterized in that the slotted member (68) is allocated to the first grid (23) and includes three substantially rectangular slots, which slits align with each and each of their different apertures between the circular apertures (64) of the first lattice and in a direction perpendicular to the direction of the main cross-sectional dimension of the focusing lens has a dimension considerably larger than its dimension in the direction of the main cross-section. 6. A system according to claim 4, characterized in that the common enclosure formed by the first main focusing electrode (27) which extends farther away from the jet outlet end of the electron gun assembly than the second main focusing electrode (29) in the direction perpendicular to the main transverse direction (f ^) of the main focusing lens is an inner cross-section (f ^) which is the same at the center of the central path among the radiation paths scm at the center of the outer paths among the radiation paths. 7. A system as claimed in claim 6, characterized in that the common enclosure formed by the second (29) main focusing electrode (29) has an internal cross-section (f) in a direction perpendicular to the main transverse direction (f f3) which is smaller at the center of the central web among the beams than it is at the center of the outer webs of the beams. 8. A system according to claim 7, characterized in that the adjacent enclosures of the two main focusing electrodes (27, 29) each have an internal maximum value dimension (f1 and f ^), which differ from each other. each other. 9. A system according to claim 8, characterized in that the maximum internal cross-dimension of the circumference of the first main focusing electrode (27) is greater than the maximum internal cross-dimension of the circumference of the second main focusing electrode (29). System according to claim 9, characterized in that the first main focusing electrode (27) is held at a potential (6500V) equal to approximately 26% of the potential (25 kV) at which the second main focusing electrode (29) halls. 11. A system according to claim 9, characterized in that the first main focusing electrode (27) also includes a hollow, substantially cylindrical portion of current conducting material which surrounds all beams and extends from the apertured, in a transverse direction. The device is provided with the portion of the first electrode adjacent to the second grid, and the device also includes: a casing of magnetizable material (31) of comparatively high permeability fitted into a segment of the cylindrical portion which is adjacent to the second grid and which protects the portions of the trajectories of the magnetic field enclosed by the envelope from magnetic fields generated by the yoke assembly. 30 12. A system according to claim 11, characterized in that the magnetizable enclosure (31) extends along less than 1/4 of the axial length of the first main focusing electrode (27b). 13. A system according to claim 6, characterized in that it comprises a first and a second auxiliary focusing electrode (27 ", 29") which encloses successive portions of the paths of the beams and is connected between them. the second grating (25 ') and the first main focusing electrode. System according to claim 13, characterized in that the first auxiliary focusing electrode (27 ") adjacent to the second grid is poured at such potential as the first main focusing electrode (21 ') and the second auxiliary focusing electrode (29") is poured at the same potential as the second main focusing electrode (29 '). 15. The system of claim 14, c h a r a c t e r i s e d in that the first auxiliary focusing electrode comprises a casing of magnetizable material 15 of relatively high permeability which circles parts of the paths of the jets and shields the circled jets of magnetic fields generated by the oscillating beam generated by the magnetic field. 16. A system according to claim 1 or 6, characterized in that the smallest distance between the inside of the neck portion and the outside of the adjacent enclosures is greater than 0.762 mm (30 mil). 17. A system according to claim 16, characterized in that the outer diameter of the neck portion is: about 29.1 mm. 18. A system as claimed in claim 1 or 6, characterized in that the compact deflection oak assembly includes a substantially toroidal core (15) of magnetizable material around which vertical deflection winding (13V) is toroidally wound. - the horizontal deflection winding (13H) is positioned relative to the core such that the radiation longitudinal end of the windows is located more remote from the display screen than the radiation longitudinal end of the core, the axial distance between the radiation longitudinal ends being equal to one