MXPA00001762A - Color picture tube having improved shadow mask frame assembly support - Google Patents

Abstract

A color picture tube (8) includes an evacuated envelope (10) having a rectangular faceplate panel (12) with two approximately parallel long sides (22, 24), two approximately parallel short sides (26, 28) and four corners. The panel comprises a faceplate (18) and a peripheral sidewall (20), and includes a shadow mask-frame assembly (38) mounted therein by springs (42) located at the four corners of the panel. The springs have apertures engaging studs (34) that are located on the peripheral sidewall at the four corners. The panel includes additional studs (54, 56) on the peripheral sidewall located near the centers of at least one pair of approximately parallel sides (22, 24) of the panel. Brackets (50, 52) are located on opposite sides of the shadow mask-frame assembly at the locations of the additional studs. The brackets include slots (59) therein. The slots are open on sides thereof facing the faceplate. The additional studs are positioned within the slots.

Description

COLOR PIPE AND PICTURE THAT HAS A SUPPORT D E SOM BRA MASK STRUCTURE ASSEMBLY.

This invention relates to a color image tube having a shadow mask attached to a peripheral structure, which is suspended in relation to the cathode-luminescent screen and, particularly with a support system for a mask structure assembly in said tube, which provides an improved shock handling capacity. In most color image tubes, a peripheral structure and a shadow mask are suspended on a faceplate panel by means of springs that are welded, either directly to the structure or to the plates, which at their Once they are welded to the structure. In large tubes, it is common to use four springs to support the mask structure assembly in the rectangular front plate panel of a tube. In many recent tubes, the springs are located in the four corners of the structure to minimize the rotation and change of position of the assembly within the panel. An opening in each spring couples a metal bolt that is integrated into an interior corner of a glass panel. A method for logging said corner support is described in the U.S. Patent. No. 4,723,088, registered to Soné et. at February 2, 1988. This patent shows a mask structure having truncated corners with supports in each corner. In the examples designated as "prior art", the mask structure assembly supports are bent metal plates that are welded to the structure at one end, and include an opening at the other end. The opening engages a metal bolt that is included in the side wall of the panel. The patent of Soné et al. teach how to form each support from two members that are soldiers. A first member, having a flat plate configuration, is welded at several separate points to a mask structure. The second member is welded to the first member at one end and includes an opening at the other end that engages a support pin on the side wall of the panel. The use of a corner support system for the support of a shadow mask of a color picture tube offers many advantages compared to the support system on axis. Hor, the corner support system has an undesirable characteristic of asymmetric resistance to shock loads. Tubes that employ corner support systems are typically less able to sustain shock loads in the horizontal direction (X) and to return the shade mask to a tolerable distance from its original position, than they are for loads of shock in the vertical direction (Y). The measure of the ability to handle the shock is a permanent deformation of the mask support system caused by subjecting the tube assemblies to an acceleration in the X direction. Such deformation commonly leads to a misalignment of the openings of the mask with respect to their normal positions, which, in turn, causes placement errors in the reception of electron beams. Such bad receptions are commonly referred to as misalignments, and, in tubes that are operating, the consequences of the misalignments are white field disuniformities and errors in color purity. Also known in the art are the continuous line screen tubes, which by their basic principle of operation, are very tolerant of alignment errors in the Y direction, but very intolerant of alignment errors in the X direction. are mounted in a usual manner in a shadow mask structure, the springs of the corner support system are typically flexible in the radial direction and very rigid in the tangential direction. These springs are typically mounted in the diagonal corners of the mask. Because the diagonal of the mask is not at 45 degrees with the X and Y axes, for example in a tube having an aspect ratio of 4x3 or 16x9 (X to Y), the resultant rigidities of the system in the X and Y directions are not equal. In tubes with an aspect ratio of 4x3, a line connecting the springs in the opposite corners makes an angle of 36.87 degrees with respect to the horizontal axis (X). A person skilled in the art could anticipate that the shock handling capacity in the horizontal direction (X) would be approximately 75% (so 36.87 degrees) of that in the vertical direction (Y). For tubes with an aspect ratio of 16x9, the difference between the shock load handling capabilities in the X and Y directions is believed to be even greater. The diagonal angle of the spring for a 16x9 aspect ratio tube is usually 29.00 degrees. This indicates that one should expect that the handling capacity of shock in the X direction would be approximately 55% (so 29.00 degrees) of that in the Y direction. It has been found that the shock handling capability of said tube with a relation 16x9 aspect may be unacceptable in many applications. The present invention addresses the problem of inadequate shock load capacity in a tube with an aspect ratio of 16x9. In accordance with the present invention, a color picture tube includes an empty coating having a rectangular face plate panel with two long sides approximately parallel, two short sides approximately parallel and four corners. The panel comprises a front plate and a peripheral side wall. The panel includes a shadow mask structure assembly mounted therein by means of springs located at the four corners of the panel. The springs have aperture coupling bolts which are located on the peripheral side wall at the four corners. The panel includes additional bolts in the peripheral side wall located near the centers of at least a pair of approximately parallel sides of the panel. Clamps are placed on opposite sides of the shadow mask structure assembly at the positions of the additional bolts. The clamps include slots inside them. The slots are open on the sides of these, facing towards the front plate. Additional bolts are placed inside the slots.

In the drawings: Figure 1 is an axially cut side view of a color picture tube exemplifying the present invention. Figure 2 is a plan view of the shadow mask structure assembly mounted within a faceplate panel of the tube of Figure 1. Figure 3 is a perspective view of a motion interruption clamp attached to the structure . Figure 4 is a perspective view of the motion interruption clamp of Figure 3 connected to a support bolt. Figure 5 is the same perspective view of another motion interruption clamp attached to the structure. Figure 6 is a perspective view of a third movement interruption clamp attached to the structure. Figure 1 shows a rectangular color image tube 8 having a glass envelope 10, comprising a faceplate panel 12 and a tubular neck 14 connected by a rectangular funnel 16. The panel 12 comprises a front faceplate 18 and a peripheral flange or side wall 20, which is sealed to the funnel 16. The faceplate panel 12 shown in Figure 2 includes two orthogonal axes: a major axis X, parallel to the approximately parallel long sides 22 and 24 ( usually horizontal) of panel 12, and a minor axis Y, parallel to the approximately parallel short sides 26 and 28 (usually vertical) of panel 12. The major and minor axes are perpendicular to the longitudinal central axis Z of the tube passing through the center of the neck 14 and the center of the panel 12. A phosphor screen with three-color mosaic 30 is carried by the inner surface of the faceplate 18. The screen 30 is preferably a screen in line with the lines of phosphorus extending substantially parallel to the minor axis Y. Alternatively, the screen may be a dot screen. A multi-aperture color selection electrode or shade mask 32 is removably mounted to the panel 12. The shade mask 32 is part of a mask structure assembly 38 that also includes a peripheral structure 40. The structure assembly The mask 38 also includes four springs 42 that engage four support bolts 34, which are included in the four corners of the panel 12, in a predetermined separate relationship with the screen 30. An electron gun 36 is centrally mounted within the neck 14 , for generating and directing the electron beams along convergent paths through the mask 32 to the screen 30. A magnetic deflection fork 41 is fixed to the tube at the junction of the neck with the funnel. The present invention improves the shock handling capability, especially of a 16x9 tube, by the addition of two clamps 50 and 52 to the mask structure assembly 38, and two additional bolts 54 and 56 to the panel 12, to provide means for stopping the movement caused by the collision of a mask structure assembly 38 along the major axis X of the tube 8. Each clamp 50 or 52 has a U-shaped configuration and is made of a single metal plate. As shown in Figures 3 and 4, one leg 57 of the U-shaped clamp is attached to the structure 40, while the other leg 58 includes a slot 59 that is open through the bottom 60 of the U-shape. of the clamp. Due to the opening in the slot 59, the clamps 50 and 52 can slide on their respective bolts, 54 and 56, without the need for any additional device for tightening the clamps. Therefore, the mask structure assembly 38 can be inserted and removed from the panel 12 by squeezing only the four corner springs 42. The additional shock load resistance in the X direction is achieved when the additional bolts engage the sides of the legs. clamp grooves, as the mask structure assembly begins to deflect in the X direction. So as not to alter the position of the shadow mask 32 in the panel 12, as defined by the corner support springs 42, the clamps 50 and 52 are welded to the structure 40 after the shadow mask is installed in the panel. Preferably, for the clamps 50 and 52 there are small tolerances of approximately 0.127 mm (0.005 inches) between the bolts 54 and 56 and the grooves of the clamps 59. The use of an open slot in a clamp, as described herein, avoids interference during the insertion and removal of the shadow mask; The clamps also do not interfere with any other processing equipment that is used in the manufacture of the tube. The configuration of the clamps may vary, to some extent, from that described with respect to the first preferred embodiment. For example, one clamp 61, shown in Figure 5, has a J-shaped configuration, and another clamp 64, shown in Figure 6, has a partially twisted J-shaped configuration. Both clamp 61 and 64 have grooves 62 and 66, respectively, within them, which are open and facing towards the faceplate 18, to allow the insertion and removal of the mask structure assembly without the need to tighten the clamps. The grooves have a generally Y-shaped configuration, with the upper tapered portion used to capture and direct the clamp over the bolt, during the insertion of the mask. The lower part of the Y shape is a V shape to accurately center the groove on the bolt, during the installation of the clamp on the structure. Once the slot is centered, the clamp is made slightly backwards, so that the pin is centered between the two parallel straight sides of the slot, with a slight tolerance between them. After the clamp has been pulled back, it is welded to the structure. Tests were performed on two diagonal tubes of 97 cm (38 inches) having aspect ratios of 16x9. A first tube had the four corner springs, but no clamp. The second tube was constructed with two clamps, in addition to the four corner springs. The results indicate that the first tube had no shock handling capacity of 25 g to tolerate a shock in the X direction, while the second tube, with the two clamps, demonstrated a shock handling capability in the X direction satisfactory to shock levels up to 35 g. Although the present invention has been described with respect to a tube having an in-line screen, which is more sensitive to horizontal misalignment than to vertical misalignment, it should be understood that the invention can also be applied to a tube having a dot screen, which is sensitive to misalignment in both horizontal and vertical directions. However, in the latter case, two additional clamps can be installed in the centers of the short sides of the panel to also improve the capacity in the vertical direction.

Claims (6)

1. A color image tube that includes an empty liner having a rectangular faceplate panel with two approximately parallel long sides, two short sides approximately parallel and four corners, the panel comprises a faceplate and a peripheral side wall, the panel furthermore includes a shadow mask structure assembly mounted within it by means of springs located at the four corners of the panel, the springs having openings that engage bolts located on the peripheral side wall at the four corners, where the panel includes additional bolts in the peripheral side wall, located near the centers of at least a pair of approximately parallel sides, and clamps located on opposite sides of the shadow mask structure assembly in the positions of the bolts, the clamps include grooves within of these, the slots are open on the sides of them, confronted the front plate, and the additional bolts are placed inside the slots. The tube according to claim 1, wherein the panel includes two additional bolts on the peripheral side wall located near the centers of the long sides, and two clamps located on the opposite long sides of the mask structure assembly. shade in the positions of the two additional bolts. The tube according to claim 2, wherein there is a small tolerance between the two additional bolts and the grooves. 4. The tube according to claim 2, wherein the panel includes an in-line screen. The tube according to claim 2, wherein the panel has an approximate aspect ratio of 16x9. The tube according to claim 2, wherein each of the grooves is generally Y-shaped, with the Y-shape having a V-shape at the bottom thereof.