JP3898788B2 - Color picture tube with improved shadow mask frame assembly support - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a color picture tube having a shadow mask attached to a perimeter frame suspended in connection with a cathode fluorescent screen, in particular to eliminate the problems due to the use of springs and washers on the support studs or It relates to an improved means of suspending the mask frame assembly in such a tube to reduce.
[0002]
[Prior art]
In most color picture tubes, the surrounding frame that supports the shadow mask is suspended from the faceplate panel by a spring that is welded directly to the frame or plate welded to the frame. In the case of direct welding, the spring is usually made of a bimetal material, and in the case of using a plate, the plate is bimetal. Since the spring or plate is heated by the transfer of heat from the mask through the frame, the bimetallic material expands differently, which causes the spring or plate to bend and move the mask frame assembly toward the screen placed on the panel. cause.
[0003]
For large tubes, it is common to use four springs to support the mask frame assembly within the glass rectangular faceplate panel of the tube. The springs are placed at the corners of the frame to minimize torsion and misalignment of the assembly within the panel. An opening in each spring engages a metal stud that is embedded in the interior corner of the panel. Examples of achieving such corner support are U.S. Pat. No. 4,723,088 issued to Sone et al. On Feb. 2, 1988 and U.S. Patent issued to Sone et al. On Mar. 1, 1988. No. 4,728,853. U.S. Pat. No. 4,723,088 shows a mask frame having diagonally cut corners with a support at each corner. The support is a curved plate that is welded to the frame at one end and includes an opening at the other end that engages a metal stud embedded in the side wall of the panel. U.S. Pat. No. 4,728,853 discloses a mask frame assembly support that includes two members welded together. One member having a flat plate shape is welded to the mask frame at several spaced points. The second member is welded to the first member at one end and includes an opening at the other end that engages a support stud in the side wall of the panel.
[Patent Literature]
US Pat. No. 3,999,098 [Patent Literature]
US Pat. No. 5,610,474 Specification
[Problems to be solved by the invention]
In a support system using four springs, it is possible to use a washer for one of the springs as taught in US Pat. No. 3,334,259 issued to Shrader on August 1, 1967. It is common. Using washers, three studs will define the support surface, but it is difficult to accurately place the fourth stud in the same plane. Thus, three of the support springs have apertures that are appropriately sized to engage each stud, and the fourth spring is a washer having an appropriately sized aperture welded to the springs. As well as large sized apertures. The purpose of using such a washer is to allow some flexibility in the location of the opening of the fourth spring washer relative to the opening of the other three springs, and all springs are suitable for the associated stud. It is to be arranged in. However, one problem that may arise when using a washer on a spring is that the stud contacts and sticks to both the spring and the washer. An advantage of the present invention is that the possibility of such sticking is reduced without affecting the curvature of the fourth spring compared to the other three springs.
[0005]
[Means for Solving the Problems]
In accordance with the present invention, a color picture tube includes a decompressed glass envelope having a rectangular faceplate panel comprising a faceplate and a peripheral sidewall. The panel includes therein a mask frame assembly attached by support means located at the corners of the panel. The mask frame assembly includes a shadow mask attached to the surrounding frame. At each corner, the support means includes a plate attached to the frame and a leaf spring. The leaf spring is attached to the plate at the first end and has an aperture in the free second end that engages a stud attached to the panel. In at least one corner, the leaf spring includes an enlarged aperture therein and a washer thereon. The washer has an aperture therein for engaging the stud. The enlarged aperture has a circular portion and a tapered portion. The tapered portion extends from the circular portion and extends toward a first end of a leaf spring attached to the plate . The tapered portion narrows toward the first end of the leaf spring.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a rectangular color picture tube having a glass envelope 10 consisting of a rectangular face panel 12 and a tubular neck 14 connected by a rectangular funnel 16. The panel 12 comprises a viewing face plate 18 and a peripheral flange or sidewall 20 sealed to the funnel 16. The face plate panel 12 includes two orthogonal axes, a main axis X parallel to a wide dimension (generally horizontal direction) and a slave axis Y parallel to a narrow dimension (generally vertical direction). The master-slave axis is perpendicular to the central longitudinal axis Z of the tube passing through the center of the neck 14 and the center of the panel 12. The mosaic three-color fluorescent screen 22 is carried by the inner surface of the face plate 18. Preferably, the screen is a line screen in which the fluorescent rays extend substantially parallel to the minor axis Y. Alternatively, the screen may be a dot screen. A perforated color selection electrode or shadow mask 24 is removably attached to the screen 22 in a predetermined spaced relationship by improved means. The electron gun 26 is mounted centrally within the neck 14 and generates three electron beams that are directed through the mask 24 along a focusing path to the screen 22.
[0007]
The tube of FIG. 1 is designed to be used with an external magnetic deflection yoke such as yoke 28 located near the funnel-neck junction. When activated, the yoke 28 causes the three beams to follow a magnetic field, which causes the beams to scan horizontally and vertically in a rectangular raster on the screen 22.
The shadow mask 24 is the part of the mask frame assembly 30 that includes the surrounding frame 32. The mask frame assembly 30 is shown disposed within the faceplate panel 12 in FIGS. The mask frame assembly 30 is attached to the panel 12 by four improved support means 34 shown in FIGS.
[0008]
Frame 32 includes two substantially vertical flanges, a first flange 36 and a second flange 38 in an L-shaped cross-sectional shape. The first flange 36 extends from the second flange 38 in the direction of the screen 22. The second flange 38 extends from the flange 36 in a direction toward the central longitudinal axis Z of the tube 8. The four corners 42 of the frame 32 are obliquely cut at an angle substantially perpendicular to the diagonal of the frame.
[0009]
The shadow mask 24 has a curved and perforated portion 25, a non-perforated end portion 27 surrounding the perforated portion 25, and a bent portion extending backward from the end portion 27 so as to be separated from the screen 22. And the existing skirt portion 29. The mask 24 extends into the frame 32 or is installed in the frame 32 and is welded to the inner surface of the first flange 36.
[0010]
Mask frame assembly support means 34 is included in each of the four corners of the frame and panel. Each support means 34 includes a stud 44, a cantilever leaf spring 46, and a plate 48. Each stud 44 is a conical metal member attached to the panel side wall 20. Each plate 48 is welded to one end of the flange 36 at an angled corner of the frame 32. The leaf spring 46 is attached to the other end of the plate 48 at one end thereof. An aperture 50 near the free end of each leaf spring 46 engages the conical portion of the stud. The plate 48, sometimes referred to as a clip, is a superposed bimetallic structure with two metal layers. One metal layer facing the frame is a high thermal expansion material, and the other metal layer facing the leaf spring is a low thermal expansion material.
[0011]
A prior art spring 52 having a washer welded thereto is shown in FIGS. Spring 52 includes two sides, each having a notch 55 therein. The spring 52 includes a large aperture 56 and the washer 54 includes a small aperture 58 that is appropriately sized for engagement with the support stud 60. In FIG. 5, the two apertures 56 and 58 are centered relative to each other. However, FIG. 6 shows that, as shown in the circled region 62, the two apertures 56 and 58 are not aligned and the stud 60 is simultaneously biting or restrained against both the spring 52 and washer 54. It shows a possible state.
[0012]
An obvious solution to reduce the constraint problem would be to make a large aperture 64 in the spring 66 as shown in FIG. However, the stress profile of the spring 68 in the tube shown in FIG. 8 shows that the enlarged circular aperture will strike the region 69 of the spring with high stress. In FIG. 8, an increase in the amount of shading indicates an increase in the amount of stress in the spring. Thus, the enlargement of the spring aperture reduces the deflection drag of the central portion of the spring, which is undesirable.
[0013]
An improved spring 70 is shown in FIGS. 9 and 10, and a combination of the improved spring 70 and washer 72 is shown in FIGS. The spring 70 has a straight side 74 and a droplet shaped aperture 76. The aperture 76 has a circular portion 78 and a three-piece or tapered portion 80. The circular portion 78 has approximately the same diameter as the diameter of the aperture 56 in the prior art spring 52. The tapered portion 80 extends toward the end of the spring attached to the plate 48. As can be seen from FIG. 8, the tapered portion 80 extends into the low stress region of the spring. Washer 72 has apertures 82 that are the same size as the other three spring apertures that directly engage their respective studs. The spring 70 has four portions that are inclined with respect to each other. The first portion 84 is generally welded to a plate such as the plate 48. The second portion 86 is inclined 15.46 degrees relative to the first portion 84 so as to be spaced from the plate. The third portion 88 extends from the second portion 86 at an angle of 11.26 degrees relative to the first portion 84. The fourth portion 90 is inclined 15.00 degrees with respect to the third portion 88.
[0014]
In a preferred embodiment for a tube having a 4x3 aspect ratio and a 79 cm rectangular viewing screen diagonal, a Carpenter Custom 455 stainless steel 0.5 mm thick leaf spring is used for a steel shadow mask. Used in combination with a .854 mm thick 3.165 cm long bimetal plate and a 1.575 mm thick 3.165 cm long bimetal plate for a nickel-iron alloy shadow mask. The maximum length of the leaf spring is 4.475 cm. The radius of the circular portion 78 of the opening 76 is 5.5 mm, and the total length of the opening 76 is 2.68 cm.
[Brief description of the drawings]
FIG. 1 is an axial cross-sectional side view of a color picture tube according to an embodiment of the present invention.
2 is a bottom view of the quadrant of the faceplate and mask frame assembly of the tube of FIG. 1. FIG.
FIG. 3 is a cross-sectional view of a corner portion of a tube panel showing a mask frame assembly supporting means.
FIG. 4 is a plan view of a prior art spring and washer.
FIG. 5 is a top view of a prior art spring and washer properly centered and engaged with a support stud.
FIG. 6 is a top view of a prior art spring and washer improperly centered and engaged with a support stud.
FIG. 7 is a plan view of a prior art spring having an enlarged aperture.
FIG. 8 is a plan view of a spring showing the position of stress therein.
FIG. 9 is a plan view of a novel spring.
10 is a side view of the spring of FIG. 9. FIG.
FIG. 11 is a plan view of the spring of FIG. 9 with a washer attached.
12 is a side view of the spring and washer of FIG. 11. FIG.
[Explanation of symbols]
8 Color picture tube 10 Envelope 12 Panel 14 Neck 16 Funnel 18 Viewing faceplate 20 Side wall 22 Fluorescent screen 24 Shadow mask 25 Opened portion 26 Electron gun 27 Non-perforated end portion 28 York 29 Skirt portion 30 Mask frame assembly 32 Peripheral frame 34 Support means 36, 38 Flange 44, 60 Stud 46 Plate spring 48 Plate 50, 82 Open hole 52, 66, 68, 70 Spring 54, 72 Washer 55 Notch 56, 64 Large aperture 58 Small aperture 74 Straight Side 76 Droplet-shaped aperture 78 Circular portion 80 Tapered portion

Claims (3)

A reduced pressure glass envelope having a rectangular faceplate panel comprising a faceplate and a peripheral sidewall, the panel including therein a shadow mask assembly attached by support means disposed at a corner of the panel. The shadow mask assembly includes a shadow mask attached to a surrounding frame, and the support means includes a plate and a leaf spring attached to the frame, the leaf spring being attached to the plate at a first end. A color picture tube having an aperture in a free second end that engages a stud attached to the panel and in which at least one corner the leaf spring has an enlarged aperture. And a washer included therein, the washer having an aperture therein for engaging the stud, wherein the enlarged Was apertures and a tapered portion at the opposite end a circular portion at one end, said tapered portion extending from the circular portion, said tapered portion a first of said plate spring mounted on the plate extend toward the end portion, a color picture tube of said tapered portion, characterized in that narrows towards said first end of said plate spring.   2. The color picture tube according to claim 1, wherein the peripheral shape of the leaf spring including the washer at the one corner is different from the peripheral shape of the remaining leaf spring not including the washer.   2. The color picture tube according to claim 1, wherein a side surface of the leaf spring at the one corner is a straight line.

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