JPH04298940A - Color image tube - Google Patents

Abstract

PURPOSE: To provide stable mechanical strength by providing an exhausted envelope having a rectangular face plate panel. CONSTITUTION: A mask-frame structure support means 34 contains a stud 52, a spring 54, and a plate shaped member 56, and the stud 52 is a cone shaped metallic member attached to a panel side wall 20. One of the edges of the plate shaped member 56 is welded to a flange 42 at a sharply bent part of a frame 32, and the spring 54 is attached to another edge of the plate shaped member 56. The stud 52 fits in a hole 58 of a free edge of the spring 54. Therefore, as it is lightweight and material saving, a small warp during a long time operation is attained to be stable against mechanical impact and vibration.

Description

[Detailed description of the invention]

0001

FIELD OF THE INVENTION The present invention relates to a color picture tube of the type having a shadow mask mounted on a peripheral frame suspended in a predetermined relationship to a viewing screen.
The present invention relates to a color picture tube having a shadow mask frame with reduced weight.

As the size of color picture tubes has increased, there has been a corresponding increase in the size and weight of the tube components. One of these elements is a shadow mask frame. Current color picture tubes use a steel frame to support the shadow mask within the tube's faceplate panel. One type of frame is formed by bending a continuous L-shaped steel member and welding the ends together. Another type of frame is formed by pressing a flat sheet of steel into the shape of the frame. The third type of frame was dated April 27, 1976 and was published by T. M. Shrader and K. Long.
．． A. Canadian Patent No. 988 issued to Mr.
, No. 141. This Canadian patent shows a frame formed of four pieces welded together at the four corners of the frame. The purpose of using four members is
This is to provide an adjustable frame that precisely fits a particular mask. Each of the four members includes two flanges configured to have an L-shaped cross section. One of the two flanges extends toward the screen of the tube, and the second flange extends from the first flange toward the central longitudinal axis of the tube. In each frame member, a first flange extends longer than a second flange at each end of the member. The extensions of these first flanges overlap each other at the corners of the frame, where the four frame members are welded together.

The three types of frames mentioned above are typically supported within the faceplate panel by three or four springs attached to the sides of the frame. Recently, large tubes have been proposed that have a mask frame supported within a faceplate by four springs located at the corners of the mask frame. The invention provides a reduced weight frame that can be used with tubes having corner supported springs.

0004

SUMMARY OF THE INVENTION An improved color picture tube according to the present invention has an evacuated envelope with a rectangular faceplate panel. The panel has a viewing screen on its inner surface and a shadow mask structure is mounted therein by support means located at the four corners of the panel. The shadow mask structure includes a perforated shadow mask and a peripheral frame to which the mask is attached. The frame includes two flanges arranged to form an L-shaped cross section. The support means are attached to the corners of the frame. According to the invention, the frame is formed by four sections welded together at each end. Each section has an elongated portion forming each side of the frame and angled corners forming the corners of the frame at each end. At both ends of each section, two flanges are in surface contact with each other and partially overlap each other. According to this construction, the frame has a certain thickness along each side thereof, with an increased thickness at each corner due to the overlap of the corners. This provides a more solid attachment area for attaching the support means.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a rectangular color picture tube 8 having a glass envelope 10. Envelope 10 includes a rectangular faceplate panel 12 and a tubular neck 14 joined by a rectangular funnel 16. Panel 12 has a viewing faceplate 18 and a peripheral flange or sidewall 20 sealed to funnel 16. The faceplate panel 12 has two orthogonal axes, a long axis X parallel to the wide dimension (usually the horizontal dimension) and a short axis Y parallel to the narrow dimension (usually the vertical dimension). have. These major and minor axes are 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. A mosaic three-color phosphor screen 22 is provided on the inner surface of the face plate 18. The screen is preferably a line screen with lines of phosphor extending substantially parallel to the minor axis Y, but may also be a dot screen. A porous color selection electrode, ie, a shadow mask 24, is removably attached to the screen 22 at a predetermined interval and positional relationship. An electron gun 26 is centered within the neck 14 and generates three electron beams that are directed along convergent paths through the mask 24 and onto the screen 22.

The tube of FIG. 1 is designed for use with an external magnetic deflection yoke 28 located near the funnel-to-neck connection. When energized, the yoke 28
places three electron beams under the influence of a magnetic field. This magnetic field acts on the beam to cause it to scan the screen 22 horizontally and vertically to trace a rectangular raster on the screen.

Shadow mask 24 forms part of a mask-frame structure 30 that includes an improved peripheral frame 32 in accordance with the present invention. Figure 1
In , mask-frame structure 30 is shown disposed within faceplate panel 12 . As shown in Figure 2, the mask-frame assembly 30 is attached to the panel 12 by four support means 34 located at the four corners of the assembly.

The mask frame 32 of the present invention is formed of four sections: two identical long sections 36 and two identical short sections 38. One of the long sections 36 is shown in FIG. 3 and one of the short sections 38 is shown in FIG. Each section has a frame edge portion and two beveled portions forming frame corners at opposite ends of the section. During assembly, the sections overlap each other at both ends and are welded together to complete the frame as shown in FIG. The overlap at the ends of each section creates a region at each corner whose thickness is the sum of the thicknesses of the two bevels, increasing the stiffness of the frame at the location of the support means. For example, a frame with each section 0.7 mm thick would have a corner thickness of 1.4 mm. To provide sufficient rigidity to the frame, embossments 40 are provided at multiple locations in all four sections of the frame.

As shown in FIGS. 6 and 7, frame 32 has two flanges 42 and 44 forming a substantially vertical L-shaped cross-sectional structure. First flange 42
extends towards the screen 22 from the joint of the two flanges, and the second flange 44 extends inwardly from the joint of the flanges in the direction of the central longitudinal axis Z of the tube 8. The four corners of frame 32 are chamfered (truncated) and angled substantially perpendicular to the diagonal of the frame.

The shadow mask 24 has a curved perforated portion 4
6. It has a non-porous boundary portion 48 surrounding the perforated portion 46, and a skirt portion 50 that is bent rearward from the boundary portion 48 and extends in a direction away from the screen 22. The mask 24 is fitted within the frame 32, i.e., located inside the frame, with the skirt portion 50 extending from the first flange 42.
welded to the inside surface of the

Mask-frame structure support means 34, shown in detail in FIG. 6, are included at each of the four corners of the frame and panel. Each support means 34 includes a stud 52;
It includes a spring 54 and a plate member 56. Each stud 52 is a conical metal member attached to the side wall 20 of the panel. Each plate member 56 is welded near one end to the flange 42 at a truncated corner of the frame 32. One end of the spring 54 is a plate member 56
attached to the other end. A conical portion of stud 52 engages a hole 58 provided near the free end of each spring 54.

Although frame 32 is shown as planar, the invention is applicable to frames of other shapes, such as barrel or arcuate shapes. A frame constructed in accordance with the present invention uses less material and is lighter than a frame of the same strength constructed from a single piece. The result is lower cost, better thermal performance, and less warpage during long-term operation. The thinner the material, the easier it is to process and the finished frame more stable against mechanical shock and vibration.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional side view taken along the axis of a color picture tube embodying the present invention.

2 is a plan view taken along line 2-2 of FIG. 1 showing a quarter section of the faceplate of the tube of FIG. 1; FIG.

FIG. 3 is a plan view of a long section of a shadow mask frame.

FIG. 4 is a plan view of a short section of a shadow mask frame.

FIG. 5 (a) is a top view of the completed shadow mask frame, (b) is a side view of the frame along line 6-6 in (a), and (c) is a side view of the frame along line 7-7 in (a). It is a side view of a frame.

6 is an enlarged cross-sectional view of a corner of the faceplate panel of the tube of FIG. 1; FIG.

7 is an enlarged plan view of a corner of the tube frame of FIG. 1; FIG.

[Explanation of symbols]

10 Envelope 12 Face plate panel 22 Screen 24 Shadow mask 32 Frame 34 Support means 42 First flange 44 Second flange

Claims (1)

[Claims] 1. An evacuated envelope with a rectangular faceplate panel, said panel having a viewing screen on its inner surface, and further provided with support means disposed at the corners of said panel. A color picture tube comprising the evacuated envelope having a shadow mask-frame structure mounted inside the tube, wherein the shadow mask-frame structure includes a perforated shadow mask and a peripheral frame to which the mask is mounted. and the support means is attached to a corner of the frame, and the frame is formed by four sections welded together at each end, each section being attached to a side of the frame. and two beveled portions forming corners of the frame at opposite ends of the section, each of these sections having a first and a second section forming a generally L-shaped cross section as a whole. consisting of members of substantially uniform thickness having two flanges, these sections being arranged so that the rectangular shape of the frame is formed;
Adjacent first and second flanges are overlap welded to each other at the bevel, so that the frame has a uniform thickness along each side and a thickness at each corner. A color picture tube having a thickness provided by superimposed bevels, thereby providing a more solid area for mounting said support means.