KR830000807B1 - Cathode ray tube with improved screen - Google Patents

Abstract

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Description

Cathode ray tube with improved screen

1 is a plan view cut along an axis of a cathode ray tube having a mask having an opening formed therein;

FIG. 2 is a rear view of the mask and face plate taken at cut line 2-2 of FIG.

3 and 4 are enlarged portions of the cathode ray tube indicated by circle 4 of FIG. 2 to explain the cathode ray tube according to the prior art and the cathode ray tube using the first embodiment of the present invention, respectively.

5 and 6 are enlarged views of a portion of a photomaster for exposing opposite sides of a shadow mask made in accordance with the present invention.

TECHNICAL FIELD The present invention relates to a cathode ray tube having a cathode light emitting line screen and a slit-type opening forming mask, and more particularly to a screening structure having improved visibility.

Recently developed and commercially available for use in color television receivers, a rectangular rectangular face plate with a line screen made of a cathode light emitting material and a shadow mask provided with a slightly spherical but slit opening adjacent to the screen are installed. It is. The slits of the masks are arranged in parallel vertical columns. Each column contains a plurality of slits vertically separated by the web portions of the mask.

The web portions of adjacent columns are vertically staggered from one another. Because of this staggering and because the length of the slit-shaped openings is generally constant, the rim line of the designated top and bottom screens preferentially cuts through the openings in each column, but sometimes cuts the web portions. The webs of some columns of the screen are adjacent to the desired screen line border while the openings of the remaining columns are adjacent to the border line, forming a step in some portions of the top and bottom edges of the screen. This staircase of screenin is aesthetically undesirable as it may be noticeable to the viewer sitting near the screenin.

The cathode ray tube according to the present invention has a cathode ray emitting line screen and a slit type aperture forming mask provided in the tube at regular intervals. The slits in the mask are arranged in a substantially parallel columnar form, each column containing a plurality of slits vertically separated by the web portions of the mask. Several end portions of the opening columns were modified to create a more aesthetically appealing screenin rim.

The invention is now described in detail by the accompanying drawings.

FIG. 1 illustrates a rectangular color water tube eninened with a vacuum glass encapsulation tube 20 consisting of a longitudinal panel 22 bonded to a funnel 26 and a tubular nach 24. An inner view of panel 22 is shown in FIG. The panel 22 is composed of a peripheral flange, that is, a wall 30 and a face plate 28 sealed to the funnel 26. The mosaic three-color cathode light emitting line screen 32 is provided on the inner surface of the face plate 28 and consists of an array of phosphor lines extending substantially parallel to the vertical axis (y-y) of the tube. The area between the cathode emission lines is also filled with light absorbing material. A color selection electrode, or shadow mask 34 (preferably illustrated), which has formed a plurality of openings, is detachably installed in the panel 22 while maintaining a predetermined distance with respect to the screen 32. Mask 34 includes a plurality of slit-shaped openings that are aligned in a substantially parallel vertical column. Each column contains a plurality of slits vertically separated by the web portions of the mask. The web portions of adjacent columns are vertically staggered so that the openings are located in a normal brick pattern when viewed sideways.

An in-line electron gun 36 (illustrated diagrammatically) is installed in the neck 24, which generates a three electron beam 38 B, 38R, 38G to form a coplanar ( coplanar) along the convergence path and through the mask 34 to the screenin 32.

The tube of FIG. 1 is designed for use with an external lateral deflection yoke 40 surrounding them near the junction of the neck 24 and funnel 26. When an appropriate voltage is applied to the yoke 40, the three electron beams 38 B, 38 R, 38G scan horizontally and vertically in a rectangular raster over which these beams are screened 32. Subject to vertical and horizontal disturbances. For simplicity, the actual curve of the passage of the deflection beams in the deflection zone is not shown in FIG. Instead, these beams are shown as instantaneously bent at the deflection plane p-p.

An enlarged view of a portion of panel 22, referred to as circle 4 in FIG. 2, is shown in FIGS. 3 and 4, respectively, with respect to the prior art water tube and the water tube containing an embodiment of the present invention, respectively.

3 shows a prior art aperture forming mask 42 partially cut away to show a portion of the screen-in 44 of the water pipe. Mask 42 includes a plurality of slits-shaped openings 46 arranged in column 48. With the exception of some openings 50 near the periphery of the mask, the lengths of all the slits shaped openings 46 are the same. Each opening 46 of each column 48 is separated from an adjacent opening of the same column by a mask web portion. In small portions of the mask shown, the lengths of these web portions are essentially the same as measured in the longitudinal direction of the slits. The center to center distance between successive web portions 52 in the same column is the vertical repeat web distance Web repeat distance (WRD). The repeating web distance continues through the entire mask. Because of this repeating web pattern and it is desirable to align the screen's edge with the slightly curved top and bottom edges of the panel 22 and mask 42, the designated border line usually not only opens the opening columns at the opening position point, Occasionally, the web is cut or cut close to, resulting in an insufficient opening pattern to perform a complete etch. These patterned but unetched openings are indicated by dotted lines 54 and 56 in FIG. Since the mask is used as a photo master to form the screen, the desired edge line passes through or near a web portion, thereby forming a screen with irregular top and bottom edges. An example of this irregular rim is shown in FIG. 3, and the phosphor line 58 having one set of three lines shows that the adjacent openings are not etched because the partial openings 56 (shown in dashed lines) are not etched. Ending at a lower point than 60).

A portion of a tube having a regular and smooth top and bottom screen edges in accordance with the present invention is shown in FIG. The mask 62, except that the mask 62 has slit-shaped openings that abut the desired border line over the entire width of all the opening columns as the upper and lower peripheral portions of the opening patterns of some columns are modified. Over most of it will have the same slit-like opening as the mask 42 of FIG. The mask 62 includes a plurality of slit-shaped openings 64 arranged in columns 66, with the openings 64 in each column being separated by a web 68. The center to center spacing between the webs 68 above the main center of the mask 62 is the repeating web distance WRD. In this embodiment, all webs with a center that can occur within a 1/2 web repeat distance from the desired rim line are missing. While forming the automaster and constructing the aperture pattern, which is used to actually expose the screen, the half-WRD in the border or the center that can cause the 1/2 WRD outside the border if the opening pattern continues beyond the border. Some webs with s are omitted. Since the web patterns outside the border are omitted because the border patterns can be shifted slightly, it affects the intersection of the border border line with the columns and also the slits. Taping the ends of the spheres does not affect the rim line contour of the screen. By removing the webs from near the opening pattern border, the end openings of all the columns will span the full width and reliably align with the top and bottom rugged border lines. Since the opening columns end along a smoothly contoured line, the resulting screen-in 70 will likewise have its top and bottom edges smooth as shown in FIG.

Although the repetitive web distance has been described herein as being constant, it should be understood that embodiments in which the repetitive web distance may be slightly changed throughout the mask to suit a particular purpose are included in the scope of the present invention. Furthermore, while the present invention has been described with respect to tubes with vertically extending opening columns, the present invention is also applicable to tubes with slitting opening columns extending horizontally.

In the shadow mask, the opening of the opening to the screen-in side of the mask is larger than that of the opening to the electron gun side of the mask. These openings are formed by first coating a thin sheet of non-etched mask material onto the photosensitive coating material and then exposing the coating from the opposite side of the thin sheet through the associated poro master. This coating is then developed and the thin plate etched to form openings. 5 and 6 show opening patterns 80 and 82 of shadow mask pot masters 84 and 86, respectively, used to expose opposite surfaces of certain shadow masks. The pattern 80 in FIG. 5 shows the opening of the opening set in the electron gun side of the mask, and the pattern 82 in FIG. 6 shows the opening of the opening to be set in the screen-in side of the mask. In each figure, the border of the opening array is shown by line 88. In the pattern 80 on the electron gun side, the elements at the end of the pattern in the edge line 88 (entries at the end of the pattern in the screen-in pattern 82) extend beyond the edge line 88. The purpose of extending the pattern arrangement on one side of the mask beyond the intended opening area is to form a blind recess in the mask to relieve the stresses that occur while forming the mask into a hemispherical shape. By weakening the peripheral area outside the aperture array, the stress on the mask webs is somewhat relieved and the chance of web cracking during shaping the mask is reduced.

5 and 6, the dashed line 90 in the rim line 88 represents the spacing of 1/2 repeat web distance. As shown, no web center point is located between the dashed line 90 and the rim line 88, providing a smooth outline around the periphery of the aperture array. In the prior art with a set repeating web distance, the position at which the web can exist is indicated as "A". However, experiments have shown that the removal of some webs in this periphery creates problems. For example, when the removal of the web made the opening at the end too long, there was excessive distortion of the opening while shaping the mask to have a hemispherical contour. Therefore, in order to compensate for this deformation, additional webs must be applied to the pattern just outside the 1/2 repeat web distance. These additional webs are labeled "B" in the figure. In general, when a center point of the web is not between 1.1 and 1.5 of the repeating web distance in the rim line 88, some web must be added. 5 and 6, the limits of 1.1 and 1.5 are designated by lines 92 and 94, respectively. An additional web “B” is applied to the center of the elongated slatted openings. The vertical dimension of the added web “B” is approximately half of the vertical dimension of a normal web.

As shown in FIG. 6, in the elongated pattern on the screen-in side of the mask 86, the same criteria are used to move the web pattern as used in the rim 88, except for coowners, which will be described later. Lose. Moving the patterned webs that are elongated is necessary so that they do not form at the site of the partial web edge 88 so as not to affect the shape or length of the opening at the site of the edge 88. In FIG. 6, the patterned web that is moved within the 1/2 repeat web distance 96 outside the rim 88 is referred to as "D".

If the patterned webs are removed at the extended pattern site, a problem of basic overweakening occurs in the nose owners of the mask. Therefore, in order to compensate for this overweaking, webs must be added to the extension pattern at the mask coowners at the edge 88 of the opening pattern. These additional webs are referred to as "C" in FIG.

Claims (1)

A cathode-emitting line screen and a slit-type opening forming mask provided in a constant relation to the screen are configured, and the slits of the mask are arranged in a column in parallel, and each column is connected to the web portions of the mask. A cathode containing multiple slits separated by, the center-to-center spacing between adjacent waves in the column throughout the main portion of the mask, defined as the web repeat distance, with the web portions of adjacent columns vertically staggered with respect to each other The tube according to claim 1, characterized in that the aforementioned columns (66) contain no centers of any web (68) within the range of 1/2 repeat web distance (WRD) from either end of the columns.

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