JPS59158056A - 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), and more particularly to the surface shape of a face plate panel of a cathode ray tube.

[Background]

There are two basic faceplate panel shapes commercially used for rectangular CR and T screens with screen sizes larger than approximately 9 inches (approximately 22.9 cm) diagonally: spherical and cylindrical. There are two shapes. A flat shape is possible, but in order to give the same strength to the envelope, the thickness of the faceplate must be increased, which increases the weight, so it is preferable. Furthermore, a flat face plate (IT or shadow mask) is preferable in the case of a color picture tube, since obtaining a suitable shadow mask increases the weight and complexity of the mask. To provide a face plate panel having a curved shape that is neither cylindrical nor cylindrical, and can create an illusion of flatness for the viewer.

[Summary of the invention]

A cathode ray tube according to the present invention includes a rectangular faceplate shouldering a curved outer surface along both long and short axes.

The curvature of the rectangular face plate along the short length 44b is, at least in the central portion of the face plate, as follows:
The curvature of the curve along the long axis becomes larger (-).

[Detailed explanation]

FIG. 1 shows a color picture tube 10 having a glass envelope 11 as a rectangular cathode ray tube. The picture tube 10 consists of a rectangular faceplate panel 12 and a tubular neck connected to a funnel 16.

Panel 12 consists of a viewing faceplate 18 and a peripheral flange or sidewall 20 sealed to annular 16 by a glass frith 17.

A rectangular tricolor phosphor screen 22 is supported on the inside surface of the faceplate 18. The screen 22 is preferably a line type screen in which the phosphor lines extend substantially parallel to the short axis Y-Y of the picture tube (in a direction perpendicular to the plane of FIG. 1). It can also be a type. A color selection electrode or shadow mask 24 having a plurality of apertures is removably provided within the faceplate panel 12 at a predetermined distance from the screen 22. An in-line electron gun 26, schematically indicated by broken lines in FIG. Although centrally located within the neck 14 for projection, the electron gun may also be triangular or delta-shaped.

The quadrant 10 of FIG. 1 is configured for use with an external magnetic deflection yoke, such as the yoke 30 shown schematically surrounding the neck 14 and funnel 16, near the junction of the neck 14 and funnel 16. has been done.

Yoke 30id: three electron beams 28 are directed horizontally along the long axis direction (X-X) so as to draw a rectangular mask on the screen 22 using vertical and horizontal magnetic fluxes.
It is also caused to scan in the vertical force direction along the short axis direction (Y-Y).

FIG. 2 shows the front side of the face plate panel 2. As shown in FIG. The periphery of the panel 12 is rectangular with slightly curved sides. The boundaries of the screen 22 are shown in dashed lines in FIG. This boundary is rectangular.

The short axis (
3, 4 and 5, respectively, and FIG. 6 shows the cross-sectional shapes along the long axis c The relative shapes of the outer surfaces of the faceplate tunnel 12 along the axis and diagonal are shown for comparison. The shape of the outer surface of the faceplate panel 12 is curved along both the short axis and the long axis, and at least in the center of the panel 12, the curvature along the short axis is equal to the curvature along the long axis. The curvature is larger than the curvature. The curvature of the surface along the diagonal is selected such that the transition of the different curvatures along the major and minor axes is smooth.

In one preferred embodiment, the curvature along the short axis is 4/3 times as large as the curvature along the long axis, at least in the middle of the faceplate. In another preferred embodiment, the shape of the faceplate along the diagonal is such that the sign of the second derivative from the center to the corner of the faceplate changes at least once.

Since the curvatures along the long axis, short axis and diagonal are different, the height A of the panel edge (side wall) 20 can be made constant over the entire periphery of the panel, as shown in FIGS. 3-5. In order to obtain such a constant height edge, the shape of the faceplate between the edge of the screen and the edge of the panel must have a suitable sliding force. If such smoothness is difficult, the height of the rim may vary slightly around the picture tube, similar to a scallop shell. That is,
It is necessary to make the height of the hem a little higher at the diagonal end than the long sleeve end and short sleeve end. This invention encompasses these two types of edges.

Because the curvatures of the curvature along the major and minor axes are different, points on the outer surface of the panel directly opposite the edges of the screen 22 all lie on substantially the same plane P. When viewed from the front of the face plate panel 12 as shown in FIG. Therefore, when the picture tube 10 of the present invention is installed in a television receiver, a boundary mask or bezel (frame material) having a uniform width can be used to surround the picture tube. The edge of such a bezel that touches the tube at the above-mentioned rectangular contour of the tube is also effectively on the plane P, since the peripheral border of the image on the picture tube screen appears to be on a plane.

Even though the faceplate panel is curved along both the long and short axes, it creates the illusion that its image is flat.

In one embodiment of a picture tube, the faceplate panel is formed of two smooth cylindrical surfaces whose axes are orthogonal to each other. The radius of these two cylindrical surfaces is determined by the plane perpendicular to the Z axis such that these two cylindrical surfaces intersect the two cylindrical surfaces that touch at the center of the flannel, and this intersection line forms a rectangle. chosen to be formed. The following equations can be used to determine the geometric parameters of the wall surface shape along the major and minor axes.

However, R1□: radius of curvature in the long axis (X) direction, R2: radius of curvature in the short axis (Y) direction, el: length of the chord of the panel in the long axis (X) direction.

e2: length of the chord of the panel in the short axis (Y) direction, It is.

The shape of this panel is parallel to the X-axis and has a radius that varies from a value on the X-axis to a maximum value compared to the warp at both ends of the short axis, and a radius parallel to the Y-axis, Y
It is determined by a radius that varies from a value at the apex to a larger value at both ends of the long axis. The above short (
Since the radius on the Y) axis is shorter than the radius on the long (X) axis, the curvature of the curve along the short axis has a larger V than that along the long axis.

The radii (Si) at the ends of the major and minor axes should be large enough so that when the faceplate is viewed from a normal viewing distance, each part of the faceplate 1 at the end of the screen appears to be a straight line. The radius can be infinite so that the peripheral border of the panel lies completely in one plane, or it can be made so that the peripheral border of the panel slightly curves out of one plane but is still virtually flat. As you can see, you can also choose a very long time.

4:L2'l) The shape of the inner surface of the face plate 8 is slightly different from the shape of the outer surface UU. In order to obtain the best possible strength-to-weight ratio of the face plate panel, the thickness of the face plates 1 and 18 must be wedged to some extent, as shown in Figure 5, for example. It's guhime.

Therefore, the thickness d of the face plate 18 increases from the center to the ends. In the example of Taio,
The degree of wedge softening along the short axis (Y-Y) is the long axis f'X
The degree of wedge softening along -X) also becomes thicker. The degree of wedge softening required will vary depending on the size of the picture tube and other design considerations. Generally, the degree of wedge softening required is approximately 1 to 3 m1Jj, which is the difference between the thick part and the thin part. In some embodiments, it may be desirable to have a faceplate that is thicker at the corners than at either end of the major or minor axis.

Shadow Mask 24 4 songs 11id, 7 x - Sufv
- substantially parallel to the curved surface of the inner surface of the plate 18; However, something that does not have such a parallel relationship is shown in US Pat. No. 4,136,300. Masks that do not have a parallel relationship with the faceplate as shown in this patent may find application in the picture tube structure of this invention, as well as the variable spacing aperture arrays shown in this patent.

FIG. 7 shows another CRT face according to this invention! It shows the deformation of the curvature of the plate surface. In the embodiment shown in this figure, the curvature of the curvature along the short axis is comparable to that of the embodiment shown in FIG.・It is very small in the center of the faceplate and increases near the edge of the faceplate. In the embodiment shown in FIG. 7, the curvature along the long sleeve is
Near the edges of the faceplate, the force is greater than the overall curvature of the curve along the minor axis. With such a design, the central portion of the faceplate is horizontal, but points on the outer surface of the faceplate at the ends of the screen lie in one plane P, as in the previous embodiment. It is located at the top and forms a rectangular outline.

The shape of the shadow mask used in the CRT faceplate panel of FIG. 7 approximately matches the shape of the panel.

The shape of such a shadow mask is generally long (X)
The curvature along the axis can be obtained by drawing the central part corresponding to the 75th section of the entire curvature as a circle with a large radius, and the remaining part as a circle with a small radius. The curved surface along the short (Y) axis is such that the curvature along the long axis smoothly conforms to the desired mask perimeter shape, and may have variations similar to those used for curvature along the long axis. .

FIG. 8 is a plan view of a shadow mask 32 shown as an embodiment of the above shadow mask.

A broken line 34 indicates the boundary line of the aperture portion of the mask 32. The surface shapes of the mask 32 along the long (X) and short (Y) axes are shown as 9a and 9b in FIG. 9, respectively.

The curvatures of the mask 32 along the long and short axes are different from each other. The shape along the long axis has a small curvature near the center and a large curvature at one end. Such a mask shape exhibits excellent doming characteristics because the degree of curvature increases near both ends of the long axis. Doming (d) occurs when the temperature of a certain part of the shadow mask becomes higher than other parts, and that part rises above the surface of the entire mask.

In a shadow mask in another embodiment (not shown), the curvature of the curvature along both the long and short axes at the center is the same, but the curvature at both ends of the long axis is greater than the curvature at both ends of the short axis. It's getting bigger. The curvature of the curvature along the periphery of the mask parallel to the long axis is smaller on both sides of the mask than the curvature of the curvature along the long axis, and the sign of the second derivative of the shape along the short axis is parallel to the short axis. The sign is opposite to that of the second-order differential of the shape on both sides of the mask.

As with the faceplate panel described above, the diagonal shape of this shadow mask must be smooth to compensate for the different curvatures. When smoothed in this way, the shape along the diagonal from the center to the even shape becomes such that the sign of its second derivative changes at least once.

The present invention can be applied to a wide range of CRs and Ts, including not only black and white picture tubes but also line screen or dot screen type shadow mask color picture tubes.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a partial axial cross section of a shadow mask color picture tube which is one embodiment of the present invention, and FIG.
Figure 2 shows the face plate panel of the picture tube shown in Figure 1.
3 to 5 are cross-sectional views of the face plate panel of FIG. 2 at lines 3-3, 4' and 5-5 of section 2; FIG. 6 shows an overall shape of the outer surface of each face plate panel 1iQI in the sectional views of FIGS. 3 1 to 5, and FIG. 7 shows a face plate 1 in another embodiment of the present invention.・A diagram showing the overall shape of the outer surface along the long axis and short axis. ・FIG. 8 is a plan view of a shadow mask that can be used for the face plate panel shown in FIG. 9.
The figure is a diagram collectively showing a cross section of the shape of the shadow mask taken along lines 9a-93 and 9b-9b in FIG. 8. 10... Cathode ray tube (color picture tube), 12... Face plate panel, 14... Tubular neck, 16. 7 anel, 18... Rectangular face plate, 20... Side wall, 22... Screen, X-X ...long axis, Y-Y...short axis. '4 Kise' DA Person: R.S.N.Y. Representative: Satoshi Shimizu and 2 others.
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~---. Continued from page 1 0 Inventor Albert Maxwell Morrell 2778 Spring Valley Road, Lancasta, Pennsylvania, USA 0 Inventor Donald Lewis Weber 265 Longfellow Drive, Lancasta, Pennsylvania, USA

Claims (1)

[Claims] (1) having a rectangular face plate with an outer surface curved along both the short axis and the long axis, the rectangular face plate 1 having a curvature along the short axis at least in its center; A cathode ray tube whose curvature along its axis is increased.