KR900005932B1 - Color picture tube having improved shadow mask - Google Patents

Abstract

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Description

Collar award tube with improved shadow mask

1 is a partial axial cross-sectional view of a shadow mask collar water tube incorporating an embodiment of the present invention.

FIG. 2 is a front view by the face plate of the collar water pipe cut along the line 2-2 of FIG.

FIG. 3 is a composite view showing the surface release of the faceplate banking in the major axis 3a-3a and the minor axis 3b-3b cross section of FIG.

4 is a front view of the shadow mask of the color receiving tube of FIG.

FIG. 5 is a composite view showing the surface appearance of the shadow mask in the major axes 5a-5a, minor axes 5b-5b and diagonal 5c-5c cross sections of FIG.

FIG. 6 is a graph showing the shadow mask opening column spacing of the mask of the color receiving tube in solid line and the opening spacing of the conventional mask in dotted line. FIG.

FIG. 7 is an enlarged view of the shadow mask taken away from circle 7 of FIG.

8 is a graph of selected screen lines of a color receiver.

9 is a front view of a shadow mask proposed by faceplate curvature showing an outline of constant height.

10 is a front view of an improved shadow mask showing the contour of a constant constant height.

* Explanation of symbols for main parts of the drawings

10: color water pipe 12: face plate digging

14: neck 16: green

18: face plate 20: side wall

22: screen 24: mask

26: electron gun 28: electron beam

30: York

FIELD OF THE INVENTION The present invention relates to a color water tube in which a slit-aperture type shadow mask is mounted in close proximity to the cathode light emitting line screen of the tube, and particularly relates to a mask opening in the water tube to provide an improved mask appearance. It is about improving the column spacing.

Most color water tubes currently being manufactured are of the line screen-slit mask type.

This tube makes a spherical face plate with a line screen of cathode light emitters rounded and a slit aperture shadow mask adjacent to the screen a rather rounded face. The slit-shaped openings in the ear canal are arranged in rows that are substantially parallel to the minor axis of the canal or gradually increase the bend from the center of the mask to the short sides.

In recent years, modifications have been made to several awards. One of these amendments is a concept related to the appearance of a new faceplate to create a flat illusion. Such amendments are described in US Patent Applications 469,722 and 469,774, filed February 25, 1983 by RCA Corporation (Inventor, F.R. Ragland Jr.). The faceplate geometry of the modified tube has curves along the major and minor axis of the faceplate panner but is not circular. These major and minor axes are defined as the central horizontal axis and the vertical axis, respectively, when the tube is in the normal viewing position.

In the preferred embodiment described in this application, the major surface boundary of the tube screen is substantially planar or visually looks like a planar. In order to obtain this planar or substantially planar peripheral boundary, it is necessary to form a faceplate panel with a curved portion along the larger major axis at the side of the panel than at the center of the panel. Non-circular formation of faceplate panels causes problems with shadow mask appearance. If the shadow mask is formed as a straight cross section parallel to the minor axis along its side, the mask may have poor mechanical properties such as undesired microphonics or may cause doming problems.

Therefore, it is desirable to form a mask having a larger curvature in this cross section than that suggested by the faceplate panel outline. However, such mask appearance modifications require other changes in the tube, including changes in the mask opening pattern.

In the first linescreen-slit mask type tube, the shadow mask was nearly circular and the separation of adjacent opening rows along the major axis (horizontal separation) remained constant relative to the mask. Later tubes of this type, however, included shadow masks with increased bends, and A.M. Opening row spacing variations described in US Pat. No. 4,136,300 to Morrell. For these later tubes, the spacing between the centerlines of one row of openings was increased from the center to the end of the mask. This increase generally varied along the main axis as the square of the distance from the main axis.

The new aperture column spacing is described in US Patent Application No. 615,589 filed March 1, 1984. In that application, the spacing between adjacent rows of openings increases from the center to the side of the shadow mask approximately four times the distance from the small axis of the shadow mask. This variation in column spacing can be expressed as a constant coefficient multiple of the fourth power of the distance, where the coefficient is variable and larger in the cross section of the mask located parallel to the central horizontal axis than in the cross section on the central horizontal side.

This quadratic variation proved to be practically suited to the shadow mask appearance of the first generation of tubes, which are Planar. This first generation of tubes has shadow masks with substantially larger bends along the minor axis than the major axis. However, the curvature from the small axis to the side of the mask is reduced so that the mask curve in the cross section parallel to the small axis is relatively flat at the side of the mask. This flatness is also undesirable because it is susceptible to deformation during handling, resulting in somewhat unexpected stretch when heated during tube operation. The present invention provides an improvement on the column spacing of the openings which allows the complementation of various curves in such shadow masks in order to obtain greater curvature in terms of the mask.

According to the present invention, a color water tube having a substantially spherical slit opening shape in which a shadow mask is mounted in relation to a substantially spherical cathodic light emitting line screen has a gap between adjacent aperture rows near the small axis of the mask. It is improved to be smaller on the long side of the mask than near the main axis.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a spherical collar water tube 10 having a glass shell 11 consisting of a tubular neck 14 connected by a faceplate pan 12 and a perimeter 16. The digging consists of an observation face plate 18 and a peripheral flange or side wall 20, which is sealed to the perimeter 16 by a glass frit 17. A new spherical tricolor cathodic fluorescent screen 22 is attached to the inner surface of the face plate 18. The screen is a line screen with fluorescent lines extending slightly parallel to the small axis Y-Y of the tube (perpendicular to the plane of FIG. 1). The outline of the fluorescent line is described in more detail below. A new number of apertured color selection electrodes, or shadow masks 24, are mounted in the faceplate drill 12 at predetermined distances from the screen 22. The inline electron gun 26, schematically shown in dashed lines in FIG. 1, also generates three electron beams 28 to be directed along the initial coplanar convergent path from the mask 24 to the screen 22. So that it is mounted at the center position in the neck 14.

The tube 10 of FIG. 1 has an external magnetic deflection yoke, for example, three beams 28 subjected to vertical and horizontal magnetic flux so that the beams are horizontally in the direction of the main axis XX in the spherical raster on the screen 22, respectively. And yoke 30 shown as surrounding the neck 14 and the perimeter 16 adjacent to its junction to scan vertically in the direction of the small axis YY.

2 shows the front surface of the faceplate pane 12. The perimeter of the pawl 12 forms a sphere with slightly curved sides. The boundary of the screen 22 is shown in phantom in FIG. 2. This screen boundary is spherical.

A comparison of the relative geometry of the outer surface of the faceplate paneer 12 along the minor axis Y-Y and the major axis X-X is shown in FIG. The outer surface of the faceplate pane 12 curves along both the major axis and the minor axis, where the curvature along the minor axis is greater than the curve along the major axis at the center of the pawl 12.

For example, at the center of the faceplate, the ratio of the counterattack of the bend of the outer surface contour along the major axis to the counterattack of the bend along the minor axis is greater than 1.1 (greater than 10% difference). However, it is small at the center of the curved faceplate along the main axis and increases greatly near the end of the faceplate. In this embodiment, the curvature along the major axis near the end of the faceplate is greater than the normal curvature along the minor axis. According to this design, the central portion of the faceplate varies, but the points on the faceplate outer surface at the end of the screen lie substantially in plane P to form a substantially spherical peripheral appearance. Surface curves along the diagonal line are selected to smooth the transition between the major and other curves along the minor axis. The curvature along the minor axis should be about 4/3 times larger than the curvature along the main axis at the center of the faceplate panel.

By using differential curvatures along the major and minor axes, the points on the outer surface of the pinar located opposite to the ends of the screen 22 are substantially coplanar P. Viewed from the front of the faceplate paneer 12 substantially planar advantages form an outline on the outer surface of the substantially spherical fielder superposed on the end of the screen 22. Thus, when the tube 10 is inserted into a television receiver, it can be used around a tube of boundary mask or bezel of uniform width. The end of this bezel in contact with the tube in the spherical outline is also substantially in the P plane. Since the peripheral boundary of the image on the tube screen appears to be planar, the image is flat even though the faceplate panner is curved outward along both the major and minor axes.

4 shows a front view of a new shadow mask 24. The dotted line 32 shows the boundary of the opening of the mask 24. In Fig. 5, the surface contours along the major axis X-X, the surface contours along the minor axis Y-Y, and the diagonal lines of the mask 24 are shown by curves 5a, 5b and 5c. Mask 24 has a curved portion that differs in curvature along its minor axis and in curvature along its major axis. The contour along the major axis is slightly curved at the center of the mask and has greater curvature at the sides of the mask. The contours of such shadow masks can generally be obtained by representing the curvature of the main axis X-X as a circle of large radius about the central part of the main axis and a smaller radius about the rest of the main axis. More specifically, however, the height of the arrow along the main axis is substantially varied by the fourth power of the distance from the small axis Y-Y. The arrow height is the distance from the imaginary plane in contact with the center of the mask surface. The curvature parallel to the minor axis Y-Y is such that the curvature of the major axis can be inserted into the periphery of the mask as needed and may include the same bend variation as used along the major axis. This mask geometry exhibits slightly improved thermal expansion properties due to increased curvature near the end of the main axis. The creation of improved thermal expansion properties due to increased curvature is described in the above-mentioned US Pat. No. 4,136,300.

FIG. 6 shows the aforementioned US patent application No. 615,589 in the quadrant of the shadow mask 24 labeled with a solid line and labeled "H" and with a dotted curve and labeled "F". is a graph showing the a _h a tropical column spacing of the openings in the quadrant of the shadow mask constructed as described in the call. The vertical coordinates of the graph represent the distance from the main axis and the horizontal coordinates represent the column-to-column spacing of the openings measured from the center line of one row to the center line of the adjacent row as shown in FIG. The number of each curve is appended to identify the space from the minor axis it represents. For example, each curve denoted by 200 represents a gap between the 200th and 201th aperture rows.

In conventional shadow masks shown with dotted curves, the column-to-row spacing of the openings is uniform along the small axis and near the small axis, as shown by curves "F" -1 and "F" -150. Some curvature can be seen at line "F" -200, which indicates that the column-to-column spacing for space 200 is increasing slightly with distance from the main axis. Curves "F" -300 and "F" -306 are quite bent, which shows that the spacing of the rows versus columns increases substantially as the distance from the main axis increases.

The column-to-row spacing of the openings of the new and improved shadow masks differs significantly from the opening-to-row spacing of conventional masks near the small axis. As shown in FIG. 6, the opening column-to-row spacing A _h near the minor axis increases in distance from the main axis as shown by curves "H" -1, "H" -100 and "H" -100. Decrease accordingly. Near the 150th space, the opening row-to-row spacing begins to increase slightly as the distance from the main axis increases, as shown slightly curved at curve "H" -150. The curvature of this curve, representing the opening column versus column spacing, increases with distance from the small axis, as shown by the curves "H" -200 and "H" -300, but the curve "H" -305 is curved "H" -300. As can be seen from the comparison, the mask decreases slightly in terms of the mask.

The opening row-to-row spacing along the major axis increases approximately as a function of the fourth power of the distance from the minor axis. In the characteristic embodiment illustrated in FIG. 6, the variation of this major axis is approximately A _h = 30 + 0.00185 × ⁴ in mils. However, off the main axis, the fluctuations in the opening column to column spacing become more complex and fluctuate according to the equation A _h = a + bx ² + cx ⁴ , where a, b and c are functions of the square of the distance from the main axis. x is the distance from the small axis.

The screen 22 of the tube 10 is formed in a known photo processing process which is used as a photograpic master with a shadow mask 24. Problems arise when a linear light source is used during the exposure phase of a photo processing process. This problem is the misalignment of the image of the linear light source with the center line of the fluorescent line. This misalignment called "skew error" makes the control of the line width more difficult by increasing the intensity distribution used to print the fluorescent line, thereby increasing the sensitivity of the phosphor width to light exposure. In the known art, an exposure technique in which a sequential exposure of another screen area as shown in US Patent No. 3,888,673 to Suzuki et al., June 10, 1975 and a tilting of the linear light source is arranged in a band shape. (zonal exposure technique) and compensation for such skew errors by various means including bending the aperture and fluorescent lines as shown in US Pat. No. 3,889,145 to Suzuki et al. June 10, 1975. This was done. In the new tube 10, the skew problem is solved by varying the opening and column to column spacing as a function of the distance from the minor axis and the distance from the major axis. The resulting fluorescent line pattern includes a curved line in the area of the screen where the skew error is greatest and a straight line on the side of the screen where the skew error in the tube is minimal. This pattern is shown in FIG. 8, where solid lines 40 to 45 represent selected spaced apart fluorescent lines and dashed lines 46 represent straight lines parallel to the minor axis. As can be seen, the curvature of the fluorescent line increases up to the maximum curvature in lines 42 to 43 as the distance from the small axis increases, and then decreases to the last line 45 which is a straight line.

The advantage of the new aperture spacing is that the curvature of the shadow mask can be made larger in the cross section near the side of the mask parallel to the minor axis than without its use. The faceplate facer with a substantially pulley end suggests a mask face as shown by line 50 in FIG. Line 50 represents the outline on mask 52 of the same height. As can be seen, line 50 is substantially straight on the left and right side of the mask. This linearity causes substantial formation and handling problems. For example, slight contact with the mask causes it to bend inward during normal handling. Therefore, it is desirable to design a mask with greater curvature in terms of the mask to avoid this problem. The use of the new aperture spacing allows for an improved mask appearance as shown by line 54 of FIG. Line 54 represents the outline on the same mask 56. In this case, line 54 is substantially curved at the left and right sides of the mast, thus giving greater curvature parallel to the minor axis and thus giving greater strength.

Claims (2)

A shadow mask 24 for a color receiver 10 having a cathode light emitting line screen 22, the shadow mask having a plurality of slit-shaped openings arranged in rows, having two opposing long sides and two opposing short sides. Has a substantially spherical periphery, the major axis XX of the mask passing through the center of the mask and extending from the center along the short side and the small axis YY of the mask passing through the center of the mask from the center along the short side The aperture row extending generally in the direction of the minor axis and spaced apart from each other in the direction of the major axis, with the aperture row to column spacing A _h near the minor axis of the mask being at the long side of the mask. The shadow mask for the collar receiving tube 10 is smaller near the major axis of the opening and the opening tropical column spacing is larger near the edge of the mask than near the main axis. In column 24, the opening column-to-row spacing along a cross section parallel to the main axis but away from the main axis varies approximately according to the equation A = a + bx ² + cx ⁴ , where A is the opening row-to-row spacing. And a, b, c are different functions of the square of the distance from the major axis and x is the distance from the minor axis. 2. The shadow mask for a color water tube according to claim 1, wherein the opening column to column spacing A _h along the major axis XX increases as a function of the quadratic power of the distance from the small axis YY.

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