MXPA96005628A - Color picture tube that has a mascaratensionada and a soporteflexi frame set - Google Patents

Abstract

The present invention relates to a color image tube (10 having a tensioned mask and a support frame assembly, each of the mask and the rectangular support frame being, and having two long sides parallel to a major axis central thereof, and two short sides parallel to a central minor axis thereof, the mask having a substantially cylindrical contour, curving along the major axis, and being straight along the minor axis, characterized in that: The frame includes two first members parallel to the major axis, and two second members, joined to the ends of the first members, parallel to the minor axis, each of the first members having a rigid region and a flexible section cantilevered from the rigid section, and joining the mask at the distal ends of the flexibl sections

Description

COLOR PICTURE TUBE THAT HAS A TENSIONED MASK AND A FLEXIBLE SUPPORT FRAME ASSEMBLY This invention relates to color picture tubes having tensioned masks attached to support frames, and particularly to a tube with a mask-frame assembly having a tensioned mask which is attached to a flexible support frame. A color image tube includes an electron gun to generate and divide three electron beams towards a screen of the tube. The screen is located on the inner surface of a face plate of the tube, and is formed of a set of emitting phosphor elements of three different colors. A mask with openings, which may be a shadow mask or a focus mask, is interposed between the gun and the screen, to allow each electron beam to impact only the phosphor elements associated with that beam. A shadow mask is a thin metallic sheet, such as steel, which is contoured to be a little parallel to the inner surface of the face plate of the tube. A focus mask comprises double sets of conductive lines that are perpendicular to one another, and normally separated by an insulating layer. One type of color picture tube has a cylindrical face plate and a tensioned shadow mask mounted thereon. In order to maintain tension on the mask, the mask must be attached to a relatively massive support frame. Although it has been found that these tubes have wide consumer acceptance, there is still a need for another improvement in the types of tubes having cylindrical face plates, to reduce the weight and cost of the mask-frame assemblies in those tubes . The present invention provides an improvement in a color image tube having a tensioned mask and a support frame assembly. Each of the mask and support frame is rectangular, and has two long sides that are parallel to a central major axis thereof, and two short sides that are parallel to a central minor axis thereof. The mask has a substantially cylindrical outline, curving along the major axis, and straight along the minor axis. The improvement comprises the frame including two first members that are parallel to the major axis, and two second members, attached to the ends of the first members, which are parallel to the minor axis. Each of the first members includes a rigid section and a flexible cantilevered section from the rigid region. The mask is attached to the distal ends of the cantilevered flexible sections. In the drawings: Figure 1 is a top view, partially in axial section, of a color image tube embodying the invention. Figure 2 is a side view, partially in axial section, of the color picture tube of Figure 1. Figure 3 is a perspective view of a tensioned-frame shadow mask assembly. Figure 4 is a perspective view of a tension-frame approach mask assembly. Figure 5 is a perspective view of a mask frame. Figure 6 is a partial cross-sectional view of the mask-frame assembly, taken on line 6-6 of Figure 3. Figure 7 is a partial cross-sectional view of the frame, taken on line 7-7 of Figure 5. Figure 8 is a partial cross-sectional view of the mask-frame assembly during manufacture. Figure 9 is a partial perspective view of another mask-frame assembly. Figure 10 is a partial plan view of a flexible section of a frame with interdigitated portions. Figures 1 and 2 show a color image tube having a glass envelope 11 comprising a rectangular face plate panel 12 and a tubular neck 14 connected by a rectangular funnel 15. The funnel 15 has an internal conductive coating (not shown) extending from an anode button. 16 to the neck 14. The panel 12 comprises a substantially cylindrical viewing face plate 18, and a peripheral flange or side wall 20, which is sealed to the funnel 15 by a glass frit 17. The inner surface of the face plate 18 carries a phosphor screen of three colors 22. The screen 22 is a line screen , with the phosphor lines configured in groups of three, each group of three including a phosphor line of each of the three colors. A substantially cylindrical multi-aperture color selection electrode or tensioned mask 24 is mounted in a removable manner in a separate predetermined relation on the display 22. The color selection electrode or tensioned mask 24 may be a shadow mask or a Focus mask. An electron gun 26, shown schematically by the dotted lines of Figures 1 and 2, is centrally mounted inside the neck 14, to generate and direct three in-line electron beams, a central beam and two lateral or external beams, as along the converging paths through the mask 24 to the screen 22. The tube 10 is designed to use an external magnetic deflection yoke such as the yoke 30 shown in the vicinity of the junction of the funnel with the neck. When activated, the yoke 30 subjects the three beams to magnetic fields that cause the beams to scan horizontally and vertically in a rectangular grid on the screen 22. The tensioned mask, shown in the form of a leftover mask tensioned 24 'in Figure 3 includes two long sides 32 and 34, and two short sides 36 and 38. The two long sides 32 and 34 of the mask parallel to a central major axis, X, of the mask; and the two short sides 36 and 38 parallel to a smaller central axis Y, of the mask. The tensioned shadow mask 24 'of Figure 3 includes an apertured portion containing a multiplicity of elongated slots that are parallel to the minor axis of the mask. Each slot extends from near one long side of the mask to near the other long side. Another form of tensioned mask, is a tensioned focus mask 24", shown in Figure 4. The tensioned focus mask 24" includes double sets of conductive lines 25 and 27, which are perpendicular to each other and separated by a layer insulator (not shown). A frame 40 for use with either a tensioned shadow mask or a tensioned focus mask, is shown in Figures 5, 6, and 7. Frame 40 includes four major members: two curved long side members 42 and 44, which are substantially parallel to the major axis X of the tube, and two straight short-side members 46 and 48, which are parallel to the minor axis Y of the tube. Each of the two curved members 42 and 44 includes a rigid section 50 and a flexible section 52 cantilevered from the rigid section. The rigid sections 50 are hollow tubes, and the flexible sections 52 are metal plates. The flexible sections 52 vary in their height (vertical dimension of section 52 in Figures 5 and 6) from the center longitudinally to the ends of the sections to allow for the best tension accommodation on the mask. Each of the straight members 46 and 48 has an L-shaped cross section. The two long sides of the mask 24 are welded to the distal ends of the flexible sections 52 of the two curved members 42 and 44. In a preferred embodiment , the rigid sections 50 of the curved members 42 and 44 are hollow square steel tubes 4130 having a wall thickness of 0.175 centimeters. The thickness of the flexible sections 52 is determined by considering the thickness of the mask, the flexibility of the total mask-frame set and the limits of the desired unwrapped envelope registration. In a further preferred embodiment, the flexible sections 52 are stainless steel plates 302 that are 0.157 centimeters thick. The flexible sections can also be bimetallic plates, such as stainless steel / stainless steel, or stainless steel / Invar. The two straight members 46 and 48 are preferably made of CRS-1018 steel having a thickness of 0.318 centimeters. In Figure 8 there is shown a method for joining the mask 24 (24 'or 24") to the flexible sections 52. First, the long sides 32 and 34 of the mask 24 are stopped by two vacuum supports 53 (one is shown ) that move apart, as shown by force vector 54, to put the mask under tension.At the same time, the flexible sections 52 are bent towards each other, as shown by the force vector 56, with the ends Then, a welding head 58 is moved along the mask 24, welding the mask to the distal ends of the flexible sections 52. Finally, the vacuum supports are removed. 53, and remove the excessive portion of the mask.

The springing of the flexible sections 52, after removing the force vector 56, keeps the mask under tension. In Figure 9 another preferred embodiment of a mask-frame assembly 60 is shown. This assembly 60 is similar to the assembly shown in Figures 3 and 5, except for the inclusion of an additional member 62 on each short side of the frame, and a change in the locations where the straight members 46 and 48 are welded to the curved members 42 and 44. Each additional member 62 is closely spaced from, and parallel to, a straight member 46 or 48 on a short side of the mask assembly - frame 60. At one end, the straight members 46 and 48 are welded to the curved member 42 at sufficient points to ensure that they are rigidly joined. At the other end, the straight members 46 and 48 are welded to the curved member 44, as shown in Figure 9, that is, at several points 64 at the top of the straight member 46, and only at a long 66 point. from the side of the straight member 46. This connection allows some degree of flexibility around the weld points 64 like the pivots. The additional members 62 are welded firmly to the bottom of both curved members 42 and 44. Preferably, the additional members 62 are 300 Series stainless steel, which has a thermal expansion coefficient different from the CRS-1018 steel of the straight members 46 and 48. When the assembly 60 is heated, the additional members 62 expand more than the straight members 46 and 48. Due to the flexible connections between the straight and curved members, the differential expansion between the additional members 62 and the straight members 46 and 48 release the traction in the flexible sections 52, and the tension in the mask 24. A modified flexible section 68 is shown in Figure 10. The modified flexible section 68 includes narrow grooves 70 (eg, 0.33 millimeters wide) which they are cut in the section from both their upper part and their lower part in an interdigitated manner. This interdigitated structure helps to minimize a wrinkling that tends to occur in the mask, due to a bad coupling by the thermal expansion between the material of the flexible section and the material of the mask. Although rigid sections 50 have been shown as hollow square tubes, other preferred configurations for this section are also possible, such as those having L-shaped, C-shaped, or triangular cross-sections. In addition, although the straight members 46 and 48 have been shown with L-shaped cross sections, other preferred configurations may be C-shaped, triangular, or box-shaped.

Claims (6)

1. A color image tube (10 having a tensioned mask (24, 24 ', 24") and a support frame assembly (40, 60), each of the mask and the rectangular support frame, and having two long sides (32, 34) parallel to a central major axis (X) thereof, and two short sides (36, 38) parallel to a central minor axis (Y) thereof, the mask having a substantially cylindrical contour, curving along the major axis, and being straight along the minor axis, characterized in that: The frame (40, 60) includes two first members (42, 44) parallel to the major axis (X), and two second members (46). , 48), attached to the ends of the first members, parallel to the minor axis (Y), each of the first members having a rigid region (50) and a flexible section (52, 68) cantilevered from the rigid section, and the mask joining the distal ends of the flexible sections

2. The color image tube (10) as defined in claim 1 , characterized in that the height of the cantilevered flexible section (52, 68) varies from the center to its ends. The color image tube (10) as defined in claim 1, characterized in that the rigid section (50) has a hollow box-shaped cross section. The color image tube (10) as defined in claim 1, characterized in that the second members (46, 48) have L-shaped cross sections. The color image tube (10) as shown in FIG. defined in claim 1, characterized by two additional members (62) spaced apart from, and parallel to, the two second members (46, 48) with the additional members being attached to the ends of the first members (42, 44), and being the additional members of a material having a coefficient of thermal expansion different from that of the second members. The color picture tube (10) as defined in claim 1, characterized in that the cantilevered flexible section (68) has grooves (70) therein, along its distal and proximal ends, forming portions interdigitated of the flexible section. SUMMARY The present invention provides an improvement in a color image tube having a tensioned mask and a support frame assembly. Each of the mask and support frame is rectangular, and has two long sides that are parallel to a central major axis thereof, and two short sides that are parallel to a central minor axis thereof. The mask has a substantially cylindrical outline, curving along the major axis, and being straight along the minor axis. The improvement comprises the frame including two first members that are parallel to the major axis, and two second members, attached to the ends of the first members, which are parallel to the minor axis. Each of the first members includes a rigid section and a flexible cantilevered section from the rigid section. The mask is attached to the distal ends of the cantilevered flexible sections. * * * * *