JPS6072146A - Cathode ray tube - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a cathode ray tube (CRT),
In particular, it relates to the surface shape of the face plate 1 of the cathode ray tube panel.

[Behind the invention]

There are two basic types of faceplate/panel contours that are commercially available and used for rectangular CRTs with screens larger than approximately 23 cm in diagonal: spherical and cylindrical. . A planar profile is also possible, but is undesirable because it increases the thickness and weight of the faceplate panel required to provide the same envelope strength. Sara pr=, flat 7 ace play 1-CR
If T is a Nyadu mask color picture tube, this is suitable, but it is not preferred because the weight of the T/Yadou mask becomes large and it becomes very complicated.

Recently, it has been proposed that spherical faceplate panels be improved by increasing the radius of curvature of the panel by a factor of 1.5 to 2.

Increasing the radius of curvature reduces the curvature of the faceplate panel, allowing satisfactory results to be obtained even when viewing the picture tube screen off-axis.

Such cathode ray tubes with a large radius of curvature may provide improved viewing conditions, or there is a desire for a cathode ray tube with a flatter face grating or even appearance.

Ideas for new faceplate panel contours that give a flat-like feel were discussed in a February 25, 1983 paper by Ragland, J.
U.S. Patent Application No. 469, 772 (corresponding to Japanese Patent Application No. 59-34113) and U.S. Patent Application No. 46
No. 9,774 (corresponding to Patent Application No. 31321 of 1983), 1
Mr. D'Amato (R, J, D'A) dated February 25, 983
mato) et al. U.S. Patent Application No. 469,775 (
(corresponding to Japanese Patent Application No. 59-31320). The profile has a 9-degree curvature in both the major and minor axes of the faceplate panel, but is not spherical. In the preferred embodiments shown in each of these patent applications, the peripheral border of the picture tube screen is a flat plate.

In such picture tubes, it is important to contour the faceplate panel so that the different curvatures extending from the major and minor axes are properly matched.

In the projection tube shown in the above-mentioned U.S. Pat. It is taken.

[Summary of the invention]

The object of the invention is to improve a cathode ray tube comprising a rectangular faceplate 1 having an outer surface with a curvature of 7H in both the major and minor axes. A cathode ray tube has a cathode ray luminescent screen on its inner surface. At least in the center of the face grating, the curvature along the short axis is at least 10 percent greater than the curvature along the long axis.

In the improved cathode ray tube, a point on the outer surface near the boot end at the edge of the screen lies in a first plane perpendicular to the longitudinal axis passing through the center of the tube, and a point on the outer surface near the boot end at the edge of the screen A point on the proximate outer surface is in a second plane parallel to said first plane and remote from this plane, and a point on the outer surface near the diagonal end of the rectangular faceplate at the edge of the screen is in said second plane parallel to said first plane and remote from said plane. 1 and in a third plane parallel to this plane and away from this plane. The three surfaces are spaced apart from the center of the faceplate in the following order: second surface, first surface, and third surface.

The present invention proposes a faceplate panel profile that appears flatter than the longer radius picture tubes described above, yet does not require the use of thicker glass to maintain strength.

[Description of preferred embodiments]

FIG. 1 shows a rectangular cathode ray tube (CRT) in the form of a color picture tube lO having a rectangular faceplate 1 . . . a glass envelope consisting of a panel 12 and a tubular neck 14 , joined by a funnel 16 show.

The panel consists of a viewing faceplate 18 and a peripheral flange or sidewall 2o bound to the funnel j6 by a glass frit 17. A rectangular tricolor cathodoluminescent phosphor screen 22 is supported by the inner surface of faceplate 18. The screen is the short axis of the tube Y-Y
A linear screen with lines of phosphor extending substantially parallel to the plane of FIG. 1 is preferred, but a dot screen may also be used. A porous color selection electrode or gloss mask 24 is removably mounted within the faceplate panel 12 at a predetermined distance 1514 from the screen 22. In Fig. 1, an in-line electron gun 2 is shown schematically by dotted lines.
6 is centered within the neck 14, and the electron gun 26 generates three electron beams 28 which are directed into a coplanar convergent path through the mask 24 and toward the screen 22. The electron gun may be triangular or delta shaped.

The picture tube 10 of FIG. 1 has a yoke 3 which surrounds the neck 14 and the funnel 1G and is shown schematically near their junction.
Designed for use with an external magnetic deflection yoke such as the
Scanning is performed horizontally in the long axis XX direction and perpendicularly in the short axis Y-Y direction so as to draw a rectangular raster over the entire surface.

FIG. 2 shows the front side of faceplate panel 12. FIG.

The perimeter of the panel 12 forms a rectangle with slightly curved sides. The boundaries of the screen 22 are indicated by dots, glands. The boundary of this screen is a rectangle with straight sides and right angle corners.

Cross-sections of a particular panel along the minor axis Y-Y, the major axis X-X, and the diagonal are shown in Figure 3.4.5, respectively. The outer surface of the faceplate panel 12 is clearly curved in both the major and minor axes, such that at least in the central portion of the faceplate panel 12, the curvature along the minor axis is more pronounced than the curvature along the major axis. It is. For example, at the center of the faceplate, the ratio of the radius of curvature of the outer surface profile along the major axis to the radius of curvature along the minor axis is greater than 1.1 (ie, more than a 10% difference). From a plane P perpendicular to the longitudinal axis Z-Z passing through the center of the picture tube and touching the center of the panel 12, another plane parallel to this plane P (for example, Pl,
Panel contour up to P2 or P3) "1 sagittal height of the second point"
was measured. The sagittal heights S H1, Sn2, and Sn2 with respect to points on the outer surface of the face plates 1 and 18 near each end of the υ axis, major axis, and diagonal are shown in FIGS. 3, 4, and 5, respectively. has been done. There is a relationship between these three sagittal heights: SHI<5H2 (Sn2).

FIG. 6 is a diagram showing the outline of the outer surface of the panel superimposed on the long axis, short axis, and diagonal line.

Each contour shape terminates at the edge of the screen.

The long axis profile ends in a first plane P1 perpendicular to the longitudinal axis Z--Z of the picture tube. The short axis profile ends in a second plane P2 parallel to and remote from the first plane P1. The diagonal profile ends in a third plane P3 in the line 'Xl/- with the first plane P1 and remote from this plane.

The three surfaces are spaced apart from the central portion of the face grating in the following order: second surface P2, first surface P1, and third surface P3. A point on the outer surface near the long axis end at the end of the screen lies within the first plane Pl. A point on the outer surface near the minor axis end at the end of the screen lies within the second plane P2.

Points on the outer surface near the ends of the diagonals at the edges of the screen lie within the third plane P3. The ratio of the distance measured along the central longitudinal axis of the picture tube between the second surface P2 and the surface P touching the center of the face plate and the distance between the third surface P3 and the surface P is: It is greater than the value obtained by dividing the length of the short axis of the screen to the power of the square by the value of the diagonal length of the screen to the power of the square, and is smaller than 1. For a picture tube with an aspect ratio of 4:3, the lower limit of this spacing ratio is approximately 9/25. 5:3 As.

For picture tubes with a pect ratio, the lower limit of this spacing ratio is approximately 9/34. Accurate calculation of the faceplate profile requires the introduction of other subtle factors, and therefore the above ratios are to be considered only as approximations.

Similarly, the distance between the first surface P1 and the surface P and the third surface P
The ratio of 3 to the spacing between plane P is greater than the square of the major axis dimension of the screen divided by the square of the diagonal dimension of the screen, and is less than 1. For a picture tube with an aspect ratio of 4:3, the lower limit of this spacing ratio t': approximately 1
It is 6/25. In a picture tube with a 5:3 aspect ratio,
The lower limit of the ratio of the distances between major axes is 25/34. In the case of scratching, the upper limit value 1 is also outside this value range since a ratio 1 indicates a flat edge facelay 1. Alternatively, the distance between the second surface P2 and the third surface P3 is equal to the distance between the third surface P3 and the surface P3, which is the square of the short axis dimension of the screen divided by the square of the diagonal dimension of the screen. is substantially equal to the distance between the

Figure 7 shows lines 3-3 (minor axis), A-A, and B-B in Figure 2.
, and the contour of the outer surface parallel to the minor axis Y-Y taken along C-CK. Each contour is a curve in which the radius of curvature of each cross section increases as the distance from j::i 1I(I+ increases.

The outer surface of one embodiment of the faceplate is represented by a fourth-order, even, bivariate polynomial i/, which gives the reference plane quadrant symmetry and a smooth surface, as shown in FIG. ing. The curve of the surface along the minor axis is a circular curve with a radius of curvature Ro. The curve of the surface of side i of the faceplate parallel to the minor axis and at the edge of the screen is also a circular curve, but with a radius of curvature Re. The curve of the surface of the cross section parallel to the short axis between the short axis and the side edge of the screen is a circular curve, and its radius of curvature is Ri. The radius of curvature Ri is a function of the distance from the short axis to the long axis, and is expressed as Ro(Ri
(The relationship Re holds true. The curve of the surface at the top and bottom of the faceplate, parallel to the long axis and at the edge of the screen, is an elliptical curve with a radius of curvature R1.

The curve of the surface along the long axis is a slightly more complex function of distance from the short axis. Basically, this long axis curve is a circular curve with a radius of curvature R near the center of the face plate, but the curvature becomes thicker near the sides of the face plate. This increase in curvature near the sides of the faceplate can be thought of as a perturbation with respect to the basic radius of curvature.

The following table shows the dimensions of a picture tube constructed as described herein and having a viewing screen with diagonal dimensions of 69 cTn (2 inches).

Table S H1------------------
-------------------18mm5H
2−−−−−−−−−−−−−”−−−−−−−−−−
-----------------22murS H3
−−−−−−−−−−−−−−−−−−−−−−−−−
-------------26amRo -------
1−−−−−−−−−−−−−−−−−−−−−−−−
---1----1150mmRe----
−1−−−−−−−−−−−−−−−−−−−−−−−
----------ri1267nmRi -------
−−−−−−−−−−−−−−−−−−−) 1150
mm and <5126m+nR1−−−−−−−−
−−−−−−−−−−−−−−−−−−−−−−−−−
---= 4574 mInH(x)-----
−−−−−−−−−−−−−−−−−−−1673mm
As is well known, on the inside screen surface of the fcR face plate 1, a suitable wedge is added to the glass for the purpose of strengthening, and the contour is improved in the form of a bivariate polynomial. .

9 to 12 compare the contour shapes of the long axis, narrow axis, and diagonal surfaces of the face plate constructed according to the present invention, indicated by dotted lines, with the four contour shapes of the face plate, indicated by solid lines. FIG. All picture tubes had a viewing screen diagonal dimension of 69 cm (2 fins).

FIG. 9 shows the outline of a spherical faceplate of standard radius IR. An example of a standard radius for a picture tube with a diagonal dimension of about 635 mm is about 1034 mm. IR
Since the face plate of is spherical, the contour shapes of the major axis and the minor axis lie on diagonal contour shapes. The sasicle height for the IR faceplate, measured between the parallel plane passing through the diagonal ends and the center of the faceplate, is 52 mm. The difference in sasicle height between the long sleeve end and the short axis end is about 15 m1n, and the difference in sasicle height between the long sleeve end and the diagonal end is about 19 m7π.

The sagittal height at the diagonal ends of the novel faceplate profile of this invention (25 + trm) is greater than the sagittal height of the standard IR faceplate (52jun)
, but the curvature of the profile shape along the short axis of the new faceplate is similar to the curvature of IRfacepre=1. This curvature in the short axis of the new faceplate provides the necessary strength without significantly increasing the thickness of the glass, allowing it to mimic external pressure when the tube is evacuated. The next two spherical faceplates with larger radii of curvature provide the necessary strength by using relatively thicker glass and therefore make the picture tube heavier.

FIG. 10 shows a radius of curvature that is 1.5 times the radius of curvature of the standard IR faceplate shown in FIG.
A spherical surface of decreasing curvature with a radius of curvature of mm x - v
- Shows the contour shape of the The sagittal height of the 1.5R faceplate is approximately 39 mm. The sagittal height difference between the long axis end and the short axis end is approximately 11. mm, the sagittal height difference between the long axis end and the diagonal end is about 15 mm.

FIG. 11 has a radius of curvature twice that of the standard IR faceplate of FIG. 9, or about 2 (+ (10
Figure 2 shows the profile of a smaller curvature spherical faceplate with a radius of curvature of mm. The sasicle height for the 2R faceplate is 26 ynm, the same as that of the new faceplate profile. The sagittal height difference between the long axis end and the short axis end is 8 tnm, and the sagittal height difference between the long axis end and the diagonal end is about 9 tnm.

Although it is theoretically possible to create a spherical face plate with an even larger radius of curvature than the 2R face plate,
Economic and commercial disadvantages result from the required weight added to the faceplate glass and the added complexity of the Nyadu mask design. However, the present invention solves the above-mentioned drawbacks while providing the advantages of a picture tube with a flat face plate in terms of viewing the display. can be provided. In a picture tube with a diagonal dimension of 69 cm, the perimeter of the novel faceplate 18 at the edge of the screen varies by only ±4 mm from the plane passing through the edge of the long axis profile. . These changes are so slight that the edges of the screen appear substantially flat to the viewer. This flat edge of the screen gives the impression that the screen is flat even though the faceplate is curved. As shown by the difference in sagittal height for each of the 1R11 and 5R12R spherical faceplate examples, such a flat feel is not obtained with these spherical examples.

FIG. 12 shows the major axis, minor axis, and diagonal face plate profile for a flat edged face plate as described in the introduction of this specification.

Such a profile presents a truly flat screen perimeter, but generally this flat edge faceplate 1
If the diagonal line 71S shape is formed with considerable curvature, some surface distortion will be observed. The present invention forms a smooth face grating surface free from undesirable surface distortion.

A preferred embodiment of a picture tube with a diagonal of 69c7n has a sagittal height difference of 4 mm between the first surface P1 and the second surface P2, and a sagittal height difference between the first surface P1 and the third surface P2. Although the sagittal height difference with plane P3 has also been described as 4 m7n, other sagittal height differences are within the scope of this invention, as indicated by the limitations cited above regarding the spacing ratio. It is something. Furthermore, the invention is not limited to any particular type of cathode ray tube screen or electron gun.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a part of a shadow mask color picture tube cut along the axis using an embodiment of the present invention, and FIG. 2 is a plan view taken along line 2-2 in FIG. 1. Front view of the faceplate panel of the picture tube, Figures 3, 4, and 5
The figures are lines 3-3, 4-4 and 5-5 of Figure 2, respectively.
Figure 6 is a cross-sectional view along the line, Figure 6 is a composite diagram showing the long axis, short axis, and diagonal outlines of the faceplate panel of the picture tube shown in Figure 1, and Figure 7 is the 3 in Figure 2. - Composite diagram showing the contours of the faceplate panel along lines A-A, B-B and C-C overlaid; FIG. Figure 9 shows the major axis, short +iQb and diagonal profile of the faceplate panel of the present invention compared to a standard radius spherical panel; Figure 10 shows 1.5x Face play of the present invention compared to a spherical panel with a standard radius of 1. The major axis, minor axis of the panel,
FIG. 11 is a diagram showing the long axis, short axis, and diagonal contour of the faceplate panel of the present invention in combination with a spherical panel of double standard radius. The figure shows the vertical and diagonal profiles of a faceplate panel of the present invention compared to an aspherical flat edge panel. 10...Cathode ray tube, 18...Face plate, 2
2...Cathode ray luminescent screen, Pl...
P2...Second surface, P3...Third surface, P...Fourth surface, X-X...Long axis, Y-Y-...Short axis, 2-2
...Isogonal lines. 4+? Applicant 7-Lune A Corporet/Yon Agent Satoshi Shimizu and 2 others Continued from page 1 0 Inventor Frank Roland 183 Juniper Road, Ragland, United States Lancaster Dell, Pennsylvania

Claims (1)

[Claims] (1) A cathode ray tube having a rectangular faceplate having an outer surface having a curvature along both a minor axis and a major axis, the faceplate having a cathode ray luminescent screen on its inner surface; the curvature along the minor axis at least at the center of the tube is at least 10 percent greater than the curvature along the major axis, and a point on the outer surface near the major axis at an edge of the screen is in a first plane perpendicular to a longitudinal axis passing through the center, a point on the outer surface near the short axis end at an edge of the screen is spaced from the first plane; is in the second plane parallel to
A point on the outer surface near the diagonal end of the rectangular faceplate at the edge of the screen is the first
The first, second and third surfaces are parallel to the first, second and third surfaces and are in a third plane that is parallel to the tenth plane. From the fourth surface in contact with the central portion of the face grating, the second surface mentioned above, the first surface mentioned above,
and the above cathode ray tube, which are separated in the order of ``2, 3 and 3''.