JPH0312422B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical field to which the invention relates] The present invention generally relates to a color image display device,
In particular, a multi-beam color picture tube with a low aberration beam focusing lens is equipped with a compact omnidirectional yoke.
The present invention relates to an apparatus for forming a novel self-focusing display capable of low stored energy operation without compromising beam focusing performance or high voltage stability.

[Prior art]

When shadow-mask multibeam color picture tubes were first used in color image display systems, dynamic concentration correction circuits were used to ensure that the beam was focused at every point in the scanning raster on the display screen. Since then, self-focusing display systems have been developed, such as those described in U.S. Pat. No. 3,800,176, which have eliminated the need for dynamic concentration correction circuits. In the system of the above-mentioned U.S. patent, three in-line electron beams are deflected by a deflection magnetic field with inhomogeneities that produce negative horizontal axial aberrations and positive vertical axial aberrations such that substantial concentration is obtained at all raster points. pass through.

When the method of the above US patent was first commercialized, the distance between the centers of adjacent beams on the deflection plane (S spacing)
was kept below approximately 5.08 mm to simplify concentration conditions; however, reducing the beam spacing in this way reduces the beam positioning opening provided in the oblong element of the focusing electrode of the electron gun source for the scanned beam. There is a limit to the diameter of the hole. Since the effective diameter of the focusing lens for each beam is determined directly by this aperture, if this aperture is small, the problem of deformation of the beam spot will occur due to spherical aberration accompanying the small diameter lens.

However, later it became possible to widen the beam spacing and increase the aperture diameter of the focusing electrode, which reduced the problem of spot deformation, but at the expense of increasing the problem of concentration.

For example, the next improvement to the self-concentrating display method described in the paper by Hamano et al., "Mininetsu Color Picture Tube" published in the March/April 1980 issue of Toshiba Review,
The outer diameter of the neck is significantly smaller (22.5 mm) than what is normally used (29.11 mm and 36.5 mm).
mm) A tube yoke structure is used in which a relatively compact deflection yoke is attached to a color picture tube. According to this paper, reducing the diameter of the neck saves horizontal deflection power, compared to the normal neck diameter.
Although the deflection sensitivity is improved by 20-30% compared to the 29.1 mm version, the size of the neck area makes it difficult to obtain sufficient focusing performance and high voltage stability (i.e., reliability against discharge). become.

[Disclosure of the invention]

It is an object of the present invention to provide a color image display device using a tube yoke structure in which deflection power saving, deflection sensitivity improvement, and yoke compactness can be achieved without relying on a reduction in neck diameter as in the above-mentioned "mini neck" system. The method of this invention has a small S interval (approximately 5.08 mm) like the above-mentioned "Mininetsu" method.
However, in the "mini-net" method, the effective focusing lens diameter is limited to be smaller than the center distance of adjacent beams incident on that lens.
A focusing electrode structure is used that forms an asymmetric main focusing lens whose major axis is three times or more larger than the beam center spacing.

Because the reduction in neck diameter of the "mini-net" method is not employed in this invention, focusing voltage levels equivalent to those commonly used in the past can be applied without sacrificing high voltage stability, and the focusing electrode structure There is adequate clearance to maintain a suitable clearance between the inner wall and the inner wall. At this voltage level, significantly higher focusing performance than that obtained with the "mini-net" approach described above is easily obtained. Also, some of the focusing performance may be sacrificed in order to relax the requirements of the focusing voltage source by operating at a reduced voltage level.

[Embodiments of the invention]

In the embodiment of the present invention, a normal tube having an outer diameter of 29.11 mm at the neck portion is used for the tube yoke structure. This eliminates the handling problems associated with the fragility of 22.5 mm diameter necks, both in tube manufacture and image display assembly, and also reduces the evacuation time associated with evacuation of "mini neck" tubes. It also solves long problems.

According to one embodiment of the invention using a 90° deflection angle, a 29.11 mm diameter tube with an S spacing of less than about 5.08 mm has an inner diameter of about 67.0 mm at the beam exit end of the horizontal deflection winding window (i.e. A self-concentrating 19V image display is provided by providing a compact deflection yoke of semi-troid type (i.e., vertical deflection winding is toroid-shaped and horizontal deflection winding is saddle-shaped) with a deflection angle of less than 0.76 mm per 1° of deflection angle. The stored energy requirement of the horizontal deflection winding of this compact 90° yoke is only 1.85 mJ at an anode voltage of 25 KV operation.

Another embodiment of the invention using a 110° deflection angle provides a tube with a similar S spacing and net diameter, with an inner diameter of about 81.5 mm at the beam exit end of the window (i.e., again per 1° deflection angle). Self-concentrating 19V with a compact semi-troid yoke (less than 0.76mm)
Displays images. The stored energy requirement for the horizontal deflection winding of this compact 110° yoke is the anode voltage
Only 3.5mJ at 25KV operation.

To appreciate the relative compactness of the yoke in the embodiment described above, it is important to note that the comparable internal diameter of a 90° deflection yoke used for a long time in the past with the wide S-spacing tubes described above is, for example, about 78.2 mm; It is sufficient to know that the inside diameter of a 110° deflection yoke used for long periods with wide S-spacing tubes is, for example, about 108.7 mm (both inside diameters are significantly greater than 0.76 mm per degree of deflection angle).

In both of the above-mentioned embodiments, a high level of focusing performance is ensured by inserting a focusing electrode structure having the general shape disclosed in US Patent Application No. 201692 into a 29.11 mm diameter neck portion. In this shape, a part of the main focusing electrode at the beam exit end of the electron gun assembly is perpendicular to the long axis of the tube neck, and three circular holes are formed here through which each electron beam passes separately.
Adjacent portions of the main focusing electrode also extend longitudinally from the portion to form a common enclosure for the entire beam path. The surrounding walls of the main focusing electrode are juxtaposed to form a common focusing lens for the beam therebetween. The inner major axis of the common surrounding wall of the last focusing electrode is, for example, 17.65 mm, and the inner major axis of the common surrounding wall of the next focusing electrode at the last end is, for example, 18.16 mm.
With this size, the internal space of the 29.11 mm diameter neck becomes wider (compared to the above-mentioned "mini neck"), creating a focusing lens whose major axis is at least 3.5 times the distance between the centers of the apertures. The required concentration effect on the beam emitted from the electron gun assembly is controlled by the difference between the long spans.

In one exemplary form of an electron gun assembly embodying the invention, the shape of the inner periphery of the common surrounding wall of the next last focusing electrode is, for example, a racetrack type as described in the above-mentioned US patent application. In contrast, the inner periphery of the common surrounding wall of the last focusing electrode has a dumbbell shape, for example, as described in US Patent Application No. 282,228. Furthermore, there is a lens asymmetry in the beam forming region of the electron gun assembly of the type that reduces the vertical dimension of each beam cross section at the entrance of the main focusing lens relative to its horizontal dimension. This asymmetry is introduced, for example, by cooperating a perpendicularly elongated rectangular opening with each circular hole in the first grid (G1) of the electron gun assembly.

By appropriately selecting the dimensions of the above-mentioned "race track type" and "drink type" surrounding walls and the rectangular aperture of G1, the permissible shape of the light spot at the center of the display raster and the edge green area can be adjusted to It is obtained by optimal balance of point aberrations.

FIG. 1 is a plan view of a picture tube yoke structure for a color image display system embodying the principles of the present invention. a substantially rectangular screen portion accommodating the screen (not shown) and a funnel portion 11 connecting the two;
F (partially shown). A yoke mounting base 17 of the deflection yoke structure 13 surrounds the adjacent portion of the neck portion 11N and the funnel portion 11F.

The yoke structure 13 includes a vertical deflection winding 13V wound toroidally around a magnetic core 15 of magnetizable material surrounding a yoke mount 17 (of insulating material) and a horizontal deflection winding 13H not visible in FIG. However, as shown in the front view of the removed yoke structure 13 in FIG.
The horizontal deflection winding 13H is wound in a saddle shape, and the effective conducting wire extending in the longitudinal direction is stuck in the throat of the yoke mount 17. The front end of the winding 13H is wound up and housed within the front edge 17F of the mounting base 17, and the rear end (not visible in FIGS. 1 and 2) is similarly housed within the rear edge 17R of the base 17. is housed in.

In FIG. 1, dimensional relationships suitable for one embodiment of the present invention are specified. Indicated by the front inner diameter "i" which corresponds to less than about 0.76 mm. Second
As shown, this inner diameter is measured at the front end of the active conductor of saddle winding 13H (ie, at the beam exit end of the window formed by the winding). The outer diameter "O" of the neck portion 11N of the color picture tube 11 is the usual 29.11 mm. An electrostatic beam focusing lens 18 (indicated by a dotted line lens) formed between the electrodes of the electron gun assembly in the network part 13 is arranged in the horizontal direction (i.e., 3
The across dimension "f" (on the horizontal plane occupied by the book's beam axes R, G, B) is 3.5 times or more the distance "g" between adjacent beam axes at the lens entrance (for example, about 5.08 mm).

FIG. 3 is a partially sectional side view of one embodiment of an electron gun assembly suitable for the neck portion 11N of the color picture tube 11 of FIG. The electrodes of the electron gun structure in FIG. 3 include three cathodes 21 (only one is visible in the side view of FIG. 3), a control grid (G1) 23, a shielding grid (G2) 25, and a first acceleration Focusing electrode (G3) 27
and a second accelerating and focusing electrode (G4) 29. Mounting bases for these electron gun elements are provided by a pair of parallel glass columns 33a, 33b, between which each electrode is supported.

Each cathode 21 is aligned with each aperture in each electrode G1, G2, G3, and G4 so that electrons emitted from the cathode can reach the display surface of the picture tube through the aperture. Electrons emitted from the cathode are transmitted by electrostatic beam forming lenses set between opposing aperture regions of the G1 and G2 electrodes 23 and 25, which are held at different unidirectional potentials (e.g., 0 volts and +1100 volts, respectively). Formed into three electron beams. Focusing of this beam onto the display surface is first performed by a main electrostatic focusing lens (18 in FIG. 1) formed between adjacent regions 27a and 29a of the G3 and G4 electrodes. For example, the G3 electrode is connected to the applied potential of the G4 electrode (e.g. +
25KV) is maintained at a potential of 26% (e.g. +6500V).

G3 electrode 27 has two flanged open ends abutting each other.
A front view of the front element 27a is shown in FIG. 4, a sectional view taken along the line C-C' is shown in FIG. 8, and a back view of the rear element 27b. is shown in FIG. 6, and a cross-sectional view taken along line E--E' is shown in FIG.

The G4 electrode 29 consists of a cup-shaped element 29a and an electrostatic shielding cup 29b whose flanged open end and apertured closed end abut against each other. The rear view of element 29a is shown in FIG. 5, and a cross-sectional view taken along line D--D' is shown in FIG.

Three openings 44 are formed in a portion 40 perpendicular to the axis that corresponds to the bottom of the concave portion at the closed front end of the G3 element 27a. The peripheral wall 42 of the concave portion, which forms a common surrounding wall for the three beams emitted from each of the apertures 44, has semicircles on both sides and parallel straight lines between them, and in the end view of FIG. It looks like a truck. The maximum horizontal inner diameter of the surrounding wall of G3 lies on the plane of the beam axis and is designated by f ₁ in FIG. Also, the maximum vertical inner diameter of the surrounding wall of G3 is determined by the interval between the parallel straight parts of the surrounding wall, and in Fig. 4 f ₂
It is expressed as. This vertical inner diameter is equal to f ₂ at any beam position.

Three openings 54 are also formed in a portion 50 perpendicular to the axis corresponding to the bottom of the concave portion at the closed rear end of the G4 element 29a. The peripheral wall 52 of the recessed part forming a common surrounding wall for the three beams incident on the G4 electrode has a parallel straight line shape at the center, but at both ends there is an excess half with a diameter larger than the parallel wall spacing at the center. It has a circular shape and looks like a "drinking bell" as shown in Figure 5. Due to this shape, the axial position of the central hole
The vertical inner diameter f ₅ of the enclosure wall of G4 is smaller than that at the axial position of the openings on both sides. The maximum horizontal inner diameter of the enclosure of G4 is in the plane of the beam axis and is designated f ₃ in FIG. The maximum vertical inner diameter of the surrounding wall of G4 corresponds to the diameter of the semicircles at both ends, and is indicated by f ₄ in FIG.

The maximum outer width of each "race track" and "dullbell" shaped region of the G3 and G4 electrodes is the same and is designated f ₆ in FIGS. 8 and 9. The diameters of the apertures 44, 54 are also the same and are indicated by d in FIGS. 8 and 9. The depths of the recesses of the G3 and G4 electrodes are also equal;
It is indicated by r in FIGS. 8 and 9. but
The depth of the hole in G3 (a ₁ in FIG. 8) and that in G4 (a ₂ in FIG. 9) are not equal. d, f ₁ , f ₂ , f ₃ , f ₄ ,
For example, the values of f ₅ , f ₆ , r, a ₁ , and a ₂ are as follows.
d=4.06mm, _f1 =18.16mm, _f2 =8.00mm, _f3 =17.65
mm, f ₄ = 7.24mm, f ₅ = 6.86mm, f ₆ = 22.22mm, r =
2.92mm, a ₁ = 0.86mm, a ₂ = 1.14mm. The center spacing g between adjacent apertures in each focusing electrode is, for example, 5.08 mm, as described with respect to FIG. Elements 27a, 29a
For example, the axial length of is 12.45 mm and 3.05 mm, respectively.
mm, and the gap between G3 and G4 of the structure in Figure 3 is, for example, 1.27
mm.

The prominent main focusing lens formed between the elements 27a and 29a has equipotential lines with relatively low curvature in the region that extends continuously between the opposing recessed wall surfaces and intersects the beam path, and has three electron It appears as a large single lens that intersects all of the beam's path. In contrast, in conventional electron guns without recesses, a significant focusing effect is provided by strong equipotential lines of relatively high curvature concentrated in each unrecessed aperture region of the focusing electrode. Since the elements 27a, 29a of the illustrated embodiment have recesses, the relatively high curvature equipotential lines in the aperture region play only a minor role in determining the quality of the focusing performance, which is rather related to the recessed wall surfaces. Determined by the size of the large lens used.

This ensures that the level of undesirable spherical aberration effects is relatively independent of aperture diameter and is dominated primarily by the dimensions of the large lens formed by the recessed wall, resulting in a narrow beam even when limiting the aperture diameter. Any spacing (such as the 5.08 mm mentioned above) can be used.
Under the above conditions, the diameter of the neck becomes a limiting factor in focusing performance, and if the above-mentioned dimensions are used in the focusing method of this invention, a good (even at the worst glass tolerance) inside the neck of the normal diameter (i.e. 29.11 mm) can be obtained. Very good focusing quality can be obtained with external dimensions of the focusing electrode such that it is easily applied with an acceptable spacing to the inner wall of the envelope that is compatible with high voltage stability. In contrast, the neck of the Hamano et al. "mini-neck" tube described above does not accommodate focusing electrode structures of the dimensions described above.

On the convergent side of the main electrostatic beam focusing lens 18 there is a concave portion of the element with race track shaped peripheral walls as described above. Such horizontal-vertical asymmetrical shape causes an astigmatism effect, and the vertical line group of the electron beam passing through the recessed part of the G3 electrode converges more than the horizontal line group. If the concave part of the G4 electrode that coexists with this is the same competitive track type, the main focusing lens 1
The divergent side of 8 also exhibits an astigmatism effect in the compensation direction.
This compensating effect is inadequately sized to prevent the presence of net astigmatism and may interfere with forming a light spot of the desired shape on the display surface.

One way to make the necessary additions to compensate for this astigmatism is to create an aperture in a plate perpendicular to the axis in the contact surfaces of elements 29a, 29b, as described in the aforementioned U.S. Patent Application No. 201692. The slot is formed using a pair of metal bands, and examples of the dimensions of each part using this method are described in the US patent application.

Another way to make the necessary additions to compensate for astigmatism is to change the shape of the recess of the G4 electrode to a "dullbell" shape, as described in the aforementioned US patent application Ser. No. 282,228. For this purpose, the diminutive shape is selected such that the reduction in the vertical dimension of the central region is substantially completely compensated for the astigmatism of the diverging part of the main focusing lens itself, or the compensation of the slot of G4 of the above type. Make selections that will supplement the effect. Examples of the dimensions of each part obtained by this method are also described in that US application.

Here, we will introduce another non-compensatory effect that combines the compensation effect of the dumbbell-shaped contour of the wall surface of the concave portion of G4 with the compensation effect obtained by introducing appropriate asymmetry into the beam forming lens formed by the G1 and G2 electrodes 23 and 25. A point aberration compensation method is used. To understand the nature of this compensatory effect,
It is appropriate to consider the structure of the G1 electrode 23 as shown in the rear view in FIG. 7 and in cross-sectional views in FIGS. 7a and 7b.

There are three apertures 64 (diameter d ₁ ) in the center of the G1 electrode 23, and each aperture communicates with a recess 66 on the back surface and a recess 68 on the front surface of the electrode 23. The shape of the peripheral wall of each concave portion 66 on the back surface is circular, and its diameter k is large enough to receive the front end of the cathode 21 (outline indicated by dotted lines in FIG. 7b) with a suitable gap. Further, the peripheral wall of each of the front recesses 68 is in the shape of a rectangular slot whose vertical dimension v is much larger than its horizontal dimension h. The center distance g between adjacent apertures 64 is the same as that of the G3 and G4 electrodes described above. Examples of other dimensions of the G1 electrode 23 are as follows. d ₁ = 0.615mm, k = 3.075mm, h = 0.711
mm, v = 2.134 mm, depth a ₃ of opening 64 = 0.102 mm, depth a ₄ of slot 68 = 0.203 mm, depth a ₅ of recess 66 = 0.457 mm. When assembled with the cathode 21 and the _G2 electrode 25, the distance between the cathode 21 and the bottom of the recessed portion 66 is, for example, 0.152 mm, and the distance between G1 and G2 is, for example, 0.178 mm.
mm.

In the assembled state shown in FIG.
The circular holes 26 are respectively the openings 64 of the G1 electrode 23.
slot 68 between them is G1.
- Introducing asymmetry on each converging side of the G2 beamforming electrode. This moves the intersection of the vertical lines of each beam further along each beam path than the intersection of the horizontal lines, so that the cross-section of each beam entering the main focusing lens has a horizontal dimension that is smaller than its vertical dimension. The direction of this "pre-deformation" of the beam cross-sectional shape is the direction that compensates for the light point deformation effect of the astigmatism of the main focusing lens.

One of the advantages of "pre-deforming" the beam before it enters the main focusing lens, as described above, is that it promotes equalization of focusing quality in the vertical and horizontal dimensions. The asymmetry of the main focusing lens means that the vertical dimension of the region of the lens that intersects the beam path is significantly larger than the diameter of the focusing electrode aperture (which limited the size of the focusing lens in conventional electron guns discussed above), but less than the horizontal dimension of that region. is of such a nature that it becomes smaller. Thus, each beam's vertical lines will see a smaller lens than its horizontal lines will see. The "pre-deformation" described above limits the vertical divergence of each beam as it passes through the main focusing lens, so that the separation of the vertical boundaries of correctly centered beams passing through a small, low quality vertical lens is large and high quality. so that the separation of the horizontal boundaries of the beam passing through the horizontal lens is less than that of the horizontal lens.

Another advantage of "pre-deforming" the beam entering the main focusing lens described above is that the yoke structure 13
The problem of vertical flare above and below the raster, which is related to an unfavorable vertical shift of the point of incidence of the beam onto the main focusing lens in response to the fringe magnetic field of the toroidal vertical winding 13V occurring behind the 13V toroidal vertical winding, is eliminated or reduced. . Although efforts are made to magnetically shield the beam from this fringe field, particularly in low velocity regions of the beam path, as described below, subsequent regions of the path are not substantially shielded from the fringe field. The aforementioned limitations on the vertical spread of each beam as it passes through the main focusing lens reduce the possibility that fringing fields will cause the shift of the point of incidence to push boundaries out of the relatively aberration-free lens region.

Another advantage of "pre-deforming" the beam entering the main focusing lens described above is to reduce the adverse effect of the main horizontal deflection field imparted by the saddle windings 13H to the spot shape on either side of the raster. In order to produce the necessary self-focusing effect in the yoke structure, the horizontally polarizing magnetic field is strongly pincushion-shaped over a significant portion of the axial length of the beam deflection region. As an unfortunate consequence of this inhomogeneity of this horizontal deflection field,
This tends to result in over-focusing of the vertical rays of each beam on both sides of the raster, but using the "pre-deformation" described above compresses the vertical dimension of each beam sufficiently as it passes through the deflection region, The overfocusing effect of is reduced to within acceptable limits.

Reference is made to US Pat. No. 4,234,814 to explain the "pre-deformation" of the beams mentioned above. In the structure of this patent, a horizontally long rectangular slot is provided on the back side of the G2 electrode in alignment and communication with each circular aperture of the G2 electrode.
This compresses the vertical dimension of each beam passing through the main focusing lens relative to its horizontal dimension by introducing an asymmetry in the diverging portion of each beam-forming lens. It can be seen that the advantage of introducing the above-mentioned asymmetry into the G1 electrode of the above-mentioned electron gun method is an improvement in the depth of focus in the vertical direction. The depth of focus obtained is usually determined by finely changing the focusing voltage (applied to the G3 electrode 27) over an appropriate range using a focusing voltage adjustment potentiometer provided in the display system, and adjusting the focusing voltage in the vertical direction. This allows optimization of horizontal focusing without significant disturbance.

As previously discussed, it is desirable to shield the low velocity region of each beam path from the backward fringing magnetic field of the deflection yoke. Therefore, the rear element 27 of the G3 electrode 27
A cup-shaped magnetic shielding element 31 is fitted into the third
As seen in the structure shown in the figure, the closed ends of both are abutted and fixed. As shown in FIGS. 6 and 10, three in-line holes 28 having circular peripheral walls are formed at the closed end of the cup-shaped element 27b, and at the closed end of the magnetic shielding fitting element 31. Three in-line apertures 32 are also formed with circular peripheral walls that align and communicate with apertures 28 when snapped into place.

In the structure of FIG. 3, aperture 28 is aligned with aperture 26 in G2 electrode 25 but axially spaced apart.
The dimensions of this part of the structure are, for example, as follows. Diameter of hole 26 = 0.615 mm, depth of hole 26 = 0.508 mm, diameter of hole 28 = 1.524 mm, hole 28
depth = 0.254 mm, diameter of hole 32 = 2.54 mm, depth of hole 32 = 0.254 mm, axial distance between aligned holes 26 and 28 = 0.838 mm, center distance between adjacent holes (as described above) g)=5.08mm. The length of the magnetic shielding fitting element 31 in the axial direction is, for example, 5.38 mm, whereas G3
For example, each of the elements 27b and 27a
They are 13.335mm and 12.45mm. The length of this shielding element (less than 1/4 of the total length of the G3 electrode) is determined by two competing wishes: to shield the beam path in the front focal region and to eliminate the distortion of the magnetic field that disturbs the concentration at the four corners. represents an acceptable compromise. The shielding element 31 is made, for example, of a magnetizable material (for example, an iron-nickel alloy of 52% nickel and 48% iron) with a higher magnetic permeability than the material of the focusing electrode element (for example, stainless steel).

The front element 29b of the G4 electrode 29 has a plurality of contact springs 30 around its front part, so as to contact the conventional carbon coating on the inner surface of the picture tube and transmit an anode potential (for example, 25 KV) to the G4 electrode. It's summery.
The closed end of the cup-shaped element 29b has a center spacing of 3, for example 5.08 mm, which passes each beam leaving the main focusing lens.
There are in-line apertures (not shown), preferably near the apertures on the inner surface of the closed end, in which a high permeability magnetic member for coma correction, such as that of US Pat. No. 3,772,554, is mounted.

The other electrodes (cathode, G1,
Application of the operating potential to G2, G3) takes place from the base of the picture tube via a conventional conductor arrangement (not shown).

The main focusing lens formed between the G3 and G4 electrodes of the structure of FIG. 3 has a net focusing effect on the three beams passing through it, so that the beams exit this lens with a tendency to concentrate, but element 27a , 29a influence the strength of this concentration effect. That is, this concentration effect increases when the size ratio favors the width of the enclosure wall of G4, and decreases when the ratio favors the width of the enclosure wall of G3. In the embodiments whose dimensions are illustrated above, it is desired to reduce the concentration effect, and G3, G4
It was found that the appropriate enclosure wall width ratio was 715/695.

When using the display system of FIG. 1, other neck enclosing devices are typically used to optimize the concentration of the beam at the center of the raster. This device may be of the adjustable magnetic ring type, for example, as described in US Pat. No. 3,725,831 or as described in US Pat.
The sheath type described in the specification of No. 4162470 may be used.

13 is a schematic illustration of a variation of the electron gun assembly of FIG. 3 that may be used in the apparatus of FIG. 1; FIG. In this variant, the shielding grid 25' and the main accelerating and focusing electrodes 27', 29'
A pair of auxiliary focusing electrodes 27'' and 29'' are provided between the two. The main focusing lens is formed between this final electrode, which in this case constitutes the G5, G6 electrodes. Auxiliary focusing electrode (G3 electrode 2) through which the beam passes first
7″) is the same potential as G5 electrode 27′ (e.g. +8KV)
The other auxiliary focusing electrode (G4 electrode 29″) is energized at the same level (e.g. 25KV) as the G6 electrode 29′.
is energized by As in the embodiment of FIG.
A respective beam is formed (from the electrons emitted from each cathode 21') by a respective beam forming lens formed between a control grid (G1 electrode 23') and a shielding grid (G2 electrode 25').

To realize this second embodiment, the G5 and G6 electrodes 27' and 29' can be replaced with G3 and G4 of the structure shown in FIG.
It has the same shape as the electrodes 27 and 29, has the above-mentioned dimensional order of "racetrack type" and "salmon shape", and is juxtaposed with a surrounding wall having the above-mentioned recessed apertures with a center spacing of 5.08 mm at the bottom. A "pre-deformation" of the beam of the type described above is also introduced by the asymmetry of each beam-forming lens. For example, G1, G2 electrodes 23', 2
5' in the form of the aforementioned U.S. Pat. No. 4,234,814;
A horizontal rectangular slot is provided on the back surface of the G1 electrode 23', and this slot is interposed between the three circular holes having a center spacing of 5.08 mm between the G1 and G2. For example, the intervening auxiliary focusing lenses 27'' and 29'', which are formed by cup-shaped elements having three in-line circular holes with center spacing as described above, are used to control the beam passing through the main focusing lens and the next deflection area. Symmetrical G3−G4 and G4−G5 with the net effect of a symmetrical reduction in cross-sectional dimensions
Introduce the lens. Although this size reduction may be desirable to reduce the overfocusing effect of the horizontal deflection field on the spot shape on either side of the raster, the central spot will be larger than in the simpler two-potential focusing scheme of Figure 3. . Using the configuration of FIG. 13, the low velocity beam path region shielding effect described for the fitting element 31 is matched by forming the G3 electrode 27'' from a high permeability material.

In order to increase the sensitivity of the deflection yoke of the method shown in Fig. 1, the shape of the conical part of the deflection area of the funnel part 11F of the tube envelope is changed by the effective conductor of the deflection winding 13H of the compact yoke. It is desirable to select a beam path as close to the outermost beam path (towards the four corners of the raster) as possible while avoiding collisions (collision with the inner surface of the funnel portion). Figure 11 is 90°
2 shows a funnel shape selected to be suitable for one embodiment of the method of FIG. 1 using deflection angles. The formula representing this shape is as follows.

X = CO + C1 (Z) + C2 (Z ² ) + C3 (Z ³ ) + C4 (Z ⁴ ) + C5 (Z ⁵ ) + C6 (Z ⁶ ) + C7 (Z ⁷ ) where X is the distance from the longitudinal axis A of the tube to the envelope The radius of the cone in mm measured toward the outer surface of It is the value expressed in mm of the distance measured in the direction, in this case C0 = 15.10490590, C1 = -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 , C7=2.482776160×
10 ^-11 , and this value is valid for Z values between 9.35 and 52.0 mm.

FIG. 12 shows a funnel shape selected to be suitable for one embodiment of the system of FIG. 1 using a 110° deflection angle. The formula representing this shape is as follows.

X = C0 + C1 (Z) + C2 (Z ² ) + C3 (Z ³ ) + C4 (Z ⁴ ) + C5 (Z ⁵ ) where X is the radius of the cone measured from the longitudinal axis A to the outer surface of the envelope expressed in mm. , Z is the distance in mm measured along axis A in the direction of the display surface from the plane Z = 0 that intersects with axis A at a point 1.27 mm in front of the joining line of the neck part and funnel part. C0=
14.5840702, C1=0.312534174, C2=
0.0242187585, C3=-6.99740898× ^10-4 , C4=
1.64032142×10 ⁻⁵ , C5=1.17802606×10 ⁻⁷ , and this value is valid for Z values from 1.53 to 50.0 mm.

For example, in the embodiment of type 19 with a deflection angle of 110° using the method shown in FIG. Envelope portion 11F, 11 between y'
The effective conductor of winding 13H is adapted to closely abut the outer surface of N. With the funnel shape of FIG. 12, the yoke of length (y-y') can be retracted (for purity control) by, for example, 5 to 6 mm without impinging the beam on the corners of the envelope.

Figure 14a shows the general form of the required inhomogeneity function H ₂ of the horizontal deflection magnetic field required for the yoke in Figure 2 to achieve self-focusing in the 110° deflection embodiment of the system in Figure 1, in practice HH ₂ . It is shown. Here, the horizontal axis indicates the position along the longitudinal axis of the tube (the position of plane Z=0 in FIG. 12 is shown for reference), and the vertical axis indicates the degree of deviation from the uniform magnetic field. In this Figure 14a,
An upward displacement (in the direction of arrow P) of the curve HH ₂ from the 0 axis indicates a "pincushion" non-uniformity of the magnetic field, and a downward displacement (in the direction of arrow B) indicates a "barrel-shaped" non-uniformity. The dotted curve HH ₀ drawn with respect to the horizontal axis at the same position shows the H ₀ function of the horizontal deflection magnetic field representing the relative magnetic field strength distribution along the tube axis. The positive wave of curve HH ₂ indicates the location of the strong pincushion field region mentioned above as the cause of the spot shape problem on both sides of the raster.

FIG. 14b shows the general form of the required inhomogeneity function H _{2 of the vertical deflection magnetic field to obtain a self-concentration result for the horizontal deflection magnetic field of FIG. 14a, with the horizontal and vertical axes being the same as in FIG. 14a} . The accompanying dotted curve VH ₀ shows the H ₀ function of the vertical deflection field and represents the relative field strength distribution along the tube axis. The left end of the curve VH ₀ demonstrates a significant spillover of the vertical deflection field to the rear of the toroidal winding 13V, as discussed above regarding the benefits of "pre-deformation" of the beam.

For example, based on the shape of FIG. 12 and suggested by the curve of FIG. 14b, the main deflection effect of the system of FIG. Occurs in nearby areas. Therefore, it can be seen that the small reduction in the net diameter relied upon in the "mini-net" method is not so important in achieving deflection efficiency. On the other hand, since there is no reduction of this type, focusing lens diameters that cannot be achieved with the "mini-net" method can be easily obtained, and high focusing quality is guaranteed, consistent with high voltage stability performance.

In FIG. 12, planes C and C' perpendicular to the axis represent the positions of the front and rear ends of the magnetic core 15 in the 110° deflection type 19 embodiment of the method shown in FIG. 1, respectively. As shown in the figure, the axial distance (y-y') between the front and rear ends of the effective conductor of the horizontal winding 13H is significantly larger (for example, 1.4 times) than the axial distance (C-C') between the front and rear ends of the magnetic core 15. , there is more than 1/2 (for example, 62.5%) of the extra conducting wire length behind the magnetic core 15. Distance between each plane (c-
y), (y−y′), and (y′−c′) are each approximately
They are 7.62mm, 50.8mm, and 12.7mm.

The feature of extending the effective conductor of the horizontal winding significantly behind the core helps to reduce the demand for stored energy (i.e., 1/2I _H L _H ² to be more specific) in the scheme and moves the horizontal center of deflection backwards. to make it easier to substantially coincide with the center of vertical deflection. This limitation on the backward travel of the horizontal windings arises from consideration of the effects on neck clearance and sufficient beam concentration at the four corners of the raster under the required yoke retraction conditions. The relative position and axial distance ratio between the winding 13H and the magnetic core 15 in FIG. It shows possible compromises. As can be seen by comparing the curves HH ₀ and VH ₀ in FIGS. 14a and 14b, the relative positions of the winding _13H and the magnetic core ₁₅ in FIG. It is desirable that the directional position substantially coincide with the directional position.

[Brief explanation of the drawing]

1 is a plan view of a combination of a picture tube and a yoke according to one embodiment of the present invention, FIG. 2 is a front view of the yoke structure of the apparatus shown in FIG. 1, and FIG. 3 is a view of the picture tube of the apparatus shown in FIG. 4, 5, 6, and 7 are end views of each element of the electron gun assembly in FIG. 3, and FIG. A cross-sectional view along line A-A' of the electron gun element of
7b is a cross-sectional view of the electron gun element in FIG. 7 taken along line B-B', and FIG. 8 is a cross-sectional view of the electron gun element in FIG. 4 taken along line C-B'.
9 is a sectional view taken along line D-D' of the electron gun element in FIG. 5, and FIG. 10 is a sectional view taken along line E-E' of the electron gun element in FIG. 6. , Figure 11 is
Figure 12 shows a picture tube funnel shape suitable for one embodiment of the invention using a 90° deflection angle;
FIG. 13 is a schematic diagram showing a modification of the electron gun assembly of FIG. 3, and FIGS. 14a and 14b are diagrams showing the yoke of FIG. FIG. 3 illustrates a non-uniformity function that may be preferably associated with one embodiment of a construction. 11N...Network part, 11F...Funnel part, 13...Yoke structure, 13H...Horizontal deflection winding, 13V...Vertical deflection winding, 18...Main focusing lens, 27, 29...Main focusing electrode, 27a, 29
a... juxtaposed parts, 40, 50... parts arranged perpendicular to the longitudinal axis, 42, 52... adjacent parts, 44, 54... inline apertures.

Claims (1)

[Scope of Claims] 1. A vacuum envelope including a screen part that accommodates a display screen, a cylindrical neck part, and a funnel part that connects the screen part and the neck part, and three in-line type vacuum envelopes installed in the neck part. a color picture tube having an electron gun structure for generating an electron beam; surrounding adjacent portions of the neck portion and the funnel portion to draw a display raster while substantially concentrating the beam over the entire screen;
It generates a deflection magnetic field that sets a predetermined deflection angle between the beam paths ending at both ends of the diagonal of the raster, with a saddle-shaped horizontal deflection winding and a toroid-shaped vertical deflection winding forming windows, respectively. a compact deflection yoke structure for setting each deflection center of the beam within the encircling area of the envelope; comprising three main focusing electrodes; each main focusing electrode having three in-line apertures disposed perpendicular to the longitudinal axis of the neck portion, through which each of the three beams passes; longitudinally extending adjacent portions forming a common enclosure for the paths of all of the beams; each adjacent portion of each of the electrodes exiting therefrom in such a manner that the beam paths converge therebetween; juxtaposed to form a common main focusing lens for the beam, and the center-to-center distance of each adjacent one of said three apertures is such that the center-to-center distance of each adjacent one of said beams passes through said center of deflection and is perpendicular to said axis. The shape of each of the juxtaposed portions is such that the major axis perpendicular to the axis of the main focusing lens is less than three times the center-to-center distance between the adjacent apertures; the diameter of the neck is large enough so that its inner surface is separated from the outer surface of the juxtaposed enclosure; the inner diameter of the compact yoke structure is set to 1 degree of the deflection angle at the beam exit of the window; A color image display device, characterized in that the color image display device is configured such that: