KR900005543B1 - Crt having a faceplate panel with an essentially planar screen periphery - Google Patents

Abstract

A C.r.t. has a square-cornered front plate on the inner surface of its screen, the outer surface of the screen being shaped such that, in the centre part of the screen, the curvature of the smaller axis (Y-Y) is at least 10 per cent greater than that of the larger axis (X-X), points towards the edge of the screen at the end of the large axis lie in a first plane lying normal to the longitudinal axis (Z-Z) of the tube. Corresp. points at the end of the smaller axis lie in a second plane lying parallel with the first plane, while points at the ends of the diagonals lie in a third plane parallel with the first plane. The three planes lie very close together in the order: second plane; first plane; third plane; the planes lying parallel to the plane tangential to the middle of the screen.

Description

Cathode ray tube

1 is a partial plan view along an axial direction of a shadow mask type color water tube of the present invention.

2 is a front view of the faceplate panel of the water pipe taken along line 2-2 of FIG.

3, 4 and 5 are cross sectional views of the faceplate panels taken along lines 3-3, 4-4 and 5-5 of FIG. 2, respectively.

6 is a composite representation of the major, minor and diagonal surface contours of the faceplate panel of FIG.

FIG. 7 is a composite representation of faceplate panel contours taken along lines 3-3, A-A, B-B and C-C of FIG. 2. FIG.

8 is a quadrant diagram showing the radius of curvature and the function of the faceplate panel of the present invention.

9 shows the contours of the major, minor and diagonal contours of the panel of the present invention as compared to the standard radial spherical panel.

10 shows the contours of the major, minor and diagonal contours of the panel of the present invention as compared to a 1.5 times standard radius spherical panel.

11 shows the contours of the major, minor and diagonal contours of the panel of the present invention as compared to twice the standard radius spherical panel.

12 shows the long axis, short axis, and diagonal contour lines of the faceplate panel of the present invention as compared to an aspherical flat panel.

* Explanation of symbols for main parts of the drawings

12: face plate panel 18: screen face plate

22: screen

The present invention relates to a cathode ray tube, and more particularly, to a surface contour of a face plate panel of a cathode ray tube.

Conventionally, two faceplate panel contour lines have been generally used for spherical, cylindrical rectangular cathode ray tubes having a screen size of 23 cm or more diagonally. Although flat contour lines may be used, the thickness and weight of the faceplate panels needed to maintain the same sheath tension are undesirable. Furthermore, there is a disadvantage in that the weight added when applying the cathode ray tube of the flat faceplate panel to the shadow mask type color receiving tube and the shadow mask suitable for it are complicated.

Recently, a method for improving the spherical cathode ray face panel by increasing the curvature radius of the panel by a factor of 1.5 to 2 has been proposed. This increase in radius of curvature reduces the curvature of the faceplate panel, resulting in a more satisfactory screen effect. However, the faceplate panel of such a cathode ray tube requires a more flat faceplate or a cathode ray tube that looks flat.

The concept of new faceplate panels exhibiting a flat shape has been described in United States Patent Application Nos. 469,722, 469,774 and 469,775, filed February 25, 1983. The contour lines have curvatures along the major and minor axis of the faceplate panel but are not spherical. In the preferred embodiment disclosed in this patent application the perimeter of the cathode ray tube screen is planar. In such a cathode ray tube, it is important that the diagonals of the faceplate panel have contours such that the different curvatures extending from the major and minor axes are properly mixed.

This mixed curvature in cited US patent application No. 469,774 results in a curvature with a minus sign of the second degree function of the diagonal outline from the center to the outward direction.

The present invention seeks to improve a cathode ray tube comprising a tetragonal faceplate panel having an outer surface with curvature along each of its short axis and long axis. The faceplate panel also includes a light emitting screen on its inner surface. At least on the central portion of the faceplate, the curvature along the short axis becomes at least 10% greater than the curvature along the long axis. The improvement is that the points on the outer surface whose major axis is close to the end, ie at the screen edge, are placed on the first plane perpendicular to the central longitudinal axis of the cathode ray tube, and the points on the outer surface whose minor axis is close to the end point. Parallel to the first plane and spaced apart and placed on the second plane. And points on the outer surface proximate the diagonal end of the tetrahedral faceplate are placed on a third plane parallel to the first plane and spaced apart. The three planes are laid out in the order of the second plane, the first plane and the third plane from the center portion of the faceplate panel.

The cathode ray tube of the present invention provides a faceplate panel that looks flatter than the previously proposed long radius cathode ray tube, and the cathode ray tube eliminates the use of thick glass to maintain strength.

The present invention will now be described in detail with reference to the drawings.

1 shows a quadrangular cathode ray tube in the form of a color water tube 10 with a glass shell 11 and comprises a tubular neck 14 connected by a quadrilateral faceplate panel 12 and a funnel 16. . The panel includes a flange 20 sealed to the funnel 16 by a screen face plate 18 and a glass material 17. A triangular tricolor fluorescent screen 22 is overlaid on the inner surface of the faceplate 18. The screen is a sunscreen formed of phosphorus extending parallel to the minor axis Y-Y of the cathode ray tube. The screen may also be formed as a point screen. The shadow mask 24 is mounted inside the faceplate panel 12 at regular intervals from the screen 22. Although the inline electron gun 26 is briefly indicated by a dotted line in FIG. 1, the electron beam is mounted at the center of the neck 14 and guided to the screen 22 through the shadow mask 24 along the converging path on the same plane. Occurs.

The water pipe 10 of FIG. 1 is designed to use an external magnetic deflection yoke, such as a yoke 30 surrounding the neck and funnel junction, and the deflection yoke 30 is a quadrilateral of the screen 22. In the raster, three electron beams 28 are subordinate to the vertical and horizontal magnetic lines so that the electron beams are scanned in the horizontal direction of the major axis XX and the vertical direction of the minor axis YY, respectively.

2 shows a front side of the faceplate panel 12. The perimeter of the panel 12 is a slightly curved rectangle. The boundary of the screen 22 is shown by the dotted line. The boundaries of this screen form a quadrilateral with a straight line and a right angle.

The minor axis (Y-Y), the major axis (X-X) and the cross section taken along the diagonal of the faceplate panel are shown in FIGS. 3, 4 and 5, respectively. The outer surface of the panel 12 is bent along its major and minor axes, where the curvature along the minor axis is greater than the curvature along the major axis at least on the center of the panel 12. For example, at the center of the faceplate panel, the ratio of the radius of curvature of the surface contour along the major axis to the radius of curvature along the minor axis is greater than 1.1 or greater than 10%. The heights SH1, SH2, SH3, indicated by arrows in the figure, are the heights from the edges of the screen 22 to the outermost circumferential surface of the face plate 18 at the ends of the short axis, the major axis and the diagonal, respectively. The heights indicated by the three arrows have the following relationship:

SH1 <SH2 <SH3

6 shows the long, short and diagonal outer panel surface contours superimposed on one another. The end of each contour ends at the edge of the screen. That is, the long axis contour ends at the first plane P1 perpendicular to the longitudinal axis Z-Z of the water pipe, and the short axis contour ends at the second plane P2 parallel to and intersect with the first plane P1. The diagonal contour lines are parallel to the first plane and end at the third plane P3 with a gap. The three planes are separated from the central portion of the plate in the order of the second plane, the first plane, and the third plane. At the edge of the screen, the points on the outermost surface of the longitudinal axis near the longitudinal axis lie on the first plane, and the points on the outermost surface of the longitudinal axis near the longitudinal axis lie on the second plane, the outer surface of the diagonal longitudinal edges. The points above lie on the third plane. The ratio of the distance measured along the central longitudinal axis of the water pipe between the tangential plane at the center of the second plane and the face plate and the distance between the third plane and plane P is squared and divided by the diagonal length of the screen and divided. It is greater than the shortening of but less than 1. If the aspect ratio of the screen of the water pipe is 3: 4, the gap ratio has a minimum limit of about 9/34. Similarly, the spacing ratio between the first plane and the plane P relative to the spacing between the third plane and the plane P is greater than and less than one, with the long axis length of the screen squared and divided by the diagonal length of the screen. If the receiving tube screen has an aspect ratio of 3: 4, then the minimum of the spacing ratio is about 16/25. If the aspect ratio of the water pipe screen is 3: 5, the minimum limit of the major axis spacing ratio is 25/34. In each case, the maximum limit would exceed the inner range since the ratio itself would refer to the flat edge of the faceplate. Also, the distance between the second plane P2 and the third plane P3 is equal to the square of the short axis of the screen, divided by the diagonal length of the screen and squared, and multiplied by the distance between the third plane and the plane P.

FIG. 7 shows the outer surface contours taken along lines 3-3, A-A, B-B and C-C of FIG. 2 and parallel to the minor axis Y-Y. Each contour is circular and each cross section becomes larger as the radius of curvature is farther from the short axis.

The outer surface according to the first embodiment of the faceplate panel is shown in FIG. 8 by quadrant. The surface curvature along the short axis is circular with a radius of curvature Ro. The surface curvature parallel to the minor axis and on the side of the faceplate panel at the edges of the screen is also circular with a radius of Re. The surface curvature at the portion parallel to the minor axis between the minor axis and the screen side is a circle whose radius is Ri. The radius of curvature is a function of the distance along the major axis from the minor axis and has the following relationship: Ro <Ri <Re

The surface curvatures at the top and bottom of the faceplate panel are circular, the radius of which is RI. Surface curvature along the long axis results in a more complex summation H (x) over distance from the short axis. Basically, the curvature of the long axis becomes circular near the center of the faceplate panel whose radius is R, but the curvature increases near the side of the faceplate. This increase leads to perturbations in the fundamental radius of curvature R.

The table below shows the dimensions of the water tube with a 27-inch diagonal screen screen configured in this way.

[table]

The inner screen surface of the faceplate is defined by adding suitable chain groups to the glass as in the prior art to increase strength.

9-12 show dotted lines representing the long axis, short axis and diagonal surface contours of the face plate constructed in accordance with the present invention.

Conventionally, four faceplate contours are shown in bold lines to be compared with the present invention. All the water tubes here have a diagonal screen size of 27 inches.

In Figure 9, standard R is represented as a spherical faceplate contour. The standard radius of the water tube with a diagonal length of about 635 mm is, for example, about 1034 mm. The height of the arrow measured between the parallel plane intersecting the diagonal ends and the central surface of the faceplate is 52 mm at the faceplate with standard radius R. The difference in arrow height between the major and minor ends is about 15 mm, and the difference in arrow height between the major and diagonal ends is about 19 mm.

Although the arrow height (26 mm) at the diagonal end of the new face plate contour is 1/2 of that of the standard R face plate (52 mm), the curvature of the new face plate contour along the short axis is very similar to the curvature of the standard face plate. similar. Such curvature along the shortening of the new faceplate provides the required strength and is able to withstand atmospheric pressure when the water tube is evacuated without significantly increasing the thickness of the glass. The two spherical face plates following this have a longer radius of curvature and the required strength can be obtained by using relatively thick glass.

FIG. 10 shows a spherical face plate contour with a radius of curvature (1500 mm) reduced to 1.5 times the radius of curvature of the standard face plate of FIG. The arrow height for the faceplate of 1.5R is about 39 mm. The difference in arrow height between the major and minor ends is about 11 mm, and the difference in arrow height between the major and diagonal ends is about 15 mm.

FIG. 11 shows a spherical face plate contour having a small curvature and has a radius of curvature twice (2000 mm) than the radius of curvature of the standard face plate of FIG. The arrow height for the face plate of 2R is 26 mm, which is the same as that of the new face plate contours. The difference in arrow height between the major and minor ends is 8 mm, and the difference in arrow height between the major and diagonal ends is about 9 mm.

Although spherical faceplates with a radius of curvature longer than those of the 2R faceplate may theoretically exist, it is difficult to commercialize due to the increased weight required to form faceplate glass and the complexity of shadow mask design. However, the novel faceplate and water tube of the present invention can provide a flatter faceplate panel water tube while avoiding the above drawbacks. The perimeter of the novel faceplate 18 of the present invention at the screen edge has a displacement of only ± 4 mm from the plane passing through the end of the long axis contour of the 69 cm diagonal water tube. Since this displacement is small, the edges of the screen appear to be actually flat to the viewer. The flat edges of the screen have the effect of appearing flat even though the actual faceplate panels have curvature.

Figure 12 shows the major, minor and diagonal faceplate contours for the flat edge faceplate as described above. Such contours provide the outline of a real flat screen. However, if it is formed to form the actual curved portion of the diagonal contour of this flat face plate, some surface distortion will appear.

Although a preferred embodiment of a 69 cm diagonal water tube has limited the difference in arrow height between the first and second planes to 4 mm, the scope of the present invention is also different as indicated by the limits based on the spacing ratios as described above. It may also include a difference in arrow height. Moreover, the present invention is not limited to any particular form of cathode ray tube screen or electron gun.

Claims (7)

A tetragonal faceplate panel having an outer surface with curvature along the minor axis and the major axis, the faceplate panel including a light emitting screen on its inner surface, the curvature along the minor axis being curvature along the minor axis, at least on the center of the faceplate; In a television receiving tube which is at least 10% larger, the points on the outer surface near the end of the long axis XX at the corners of the screen 22 are first perpendicular to the central longitudinal axis ZZ of the receiving tube 10. Points on a plane P1, the points on the outer surface of which the minor axis YY at the edge of the screen are near the end, lie on a second plane P2 parallel to the first plane and spaced apart, and Points on the outer surface near the diagonal end of the tetragonal plate 18 lie on a third plane P3 parallel to and spaced from the first plane, wherein the first, second and third planes are A second plane parallel to the first, second, and third planes and in the center portion of the faceplate; , The first plane and the third plane are spaced apart from the fourth plane P, which is in contact with each other, and the outer surface curvature along the short axis is rounded from the center of the face plate to the second plane, and the outer surface curvature along the long axis. Is rounded on the center of the face plate, the curvature of the cathode tube is characterized in that its curvature increases from the vicinity of the edge of the face plate to the first plane. The center longitudinal axis (ZZ) of the water pipe (10) according to claim 1, wherein the ratio of the space (SH1) between the second and fourth planes to the space (SH3) between the third and fourth planes is determined. A cathode ray tube, characterized in that it is greater than the value obtained by dividing the diagonal length of the screen by the square divided by providing the shortened length of the screen (22). The method of claim 2, wherein the square length of the screen 22 of the water pipe having a screen aspect ratio of 3: 4 divided by the square length of the screen is divided by greater than 9/25 and smaller than 1. Cathode ray tube characterized in that. 3. The method of claim 2, wherein the square length of the screen 22 of the water pipe having an aspect ratio of 3: 5 divided by the square length of the diagonal of the screen is greater than 9/34 and less than one. Cathode ray tube characterized in that. The center longitudinal axis (ZZ) of the water pipe (10) according to claim 1, wherein the ratio of the distance (SH1) between the first and fourth planes to the interval (SH3) between the third and fourth planes is determined. The cathode ray tube, characterized in that greater than the value obtained by dividing the length of the long axis of the screen (22) by the square divided by the length of the diagonal of the screen. 6. A value according to claim 5, wherein the aspect ratio of the screen is obtained by dividing the length of the long axis of the screen 22 by the square of the diagonal length of the screen, which is greater than 16/25 and less than 1 in a water pipe having a 3: 4 ratio. Cathode ray tube having a. 6. A value according to claim 5, wherein the square of the long axis of the screen 22 of the water pipe having an aspect ratio of 3: 5 divided by the diagonal of the screen is greater than 25/34 and less than one. Cathode ray tube characterized in that it has.

Images