JPS6024533B2 - How to make a shadow mask - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a shadow mask for a color cathode ray tube, particularly a color cathode ray tube called a black stripe type color cathode ray tube.

A black stripe type color cathode ray tube has three independent and continuous rear light stripes arranged vertically and repeatedly in the horizontal direction of the screen on the inner surface of the panel, forming a shadow mask 1 as shown in Fig. 1. Three electron beams corresponding to each color are irradiated onto the crab light strips of each color through the slotted aperture 2 that has been formed, so that the three primary colors are emitted. By creating a stripe shape, the vertical landing margin of the electron beam is increased and the comparability circuit of the receiver can be simplified. By filling both sides of the three-color crab light stripe with a light-absorbing material such as graphite, and by irradiating the entire width of the crab light stripe with an electron beam whose width is larger than the width of each halo stripe, an image can be created. The aim is to improve contrast and rear light surface brightness.

Therefore, the light emitting balance of the three-color crab light body depends on whether the black stripes that restrict the width of each crab light body stripe have the same width between the three colors and whether the shape is correct across the entire screen. This is the most important factor in screen uniformity. By the way, while the crab light body and the black stripe are each formed in a continuous stripe shape in the vertical direction, the aperture formed in the shadow mask 1 is divided into vertically divided slotted apertures 2 as shown in FIG. must be configured.

This is because in this type of color cathode ray tube, the inner surface of the panel and the shadow mask 1 are formed into a spherical surface or a curved surface similar to a spherical surface in order to accurately land the electron beam. In order to maintain the shape of the curved surface, the slotted aperture 2 cannot be made continuous in the vertical direction, so it is formed by dividing it into a plurality of parts, and the bridge part 9 is formed between them. For this reason, in forming the black stripes and crab light stripes, the photocurable resin coated on the inner surface of the panel is exposed to light from a light source through a shadow mask, as is generally known.
The exposed photocurable resin or crab photo material is left behind and the other parts are removed to form the desired crab photo material stripes and black stripes, so exposure is performed through a shadow mask. In this case, the image of the light source formed on the inner surface of the panel must be in the form of continuous stripes in the vertical direction. However, due to the presence of the bridge portion 3, this portion becomes a shadow, making it impossible to form a continuous stripe image. For this reason, a linear light source is used, and its longitudinal direction is defined by a slotted aperture 2.
By arranging the linear light source in the same direction as the longitudinal direction of the light source and forming an image of the linear light source on the inner surface of the panel through the slotted aperture 2, continuous image formation without the influence of the bridge portion 3 can be obtained. However, simply using a linear light source will cause the imaging stripe S to bend as it approaches the periphery of the panel 4, especially the four corners, as shown in FIG. Formed in this bent shape, the image quality is significantly impaired, and this effect is particularly large in the case of a black stripe type.

For this reason, in the past, in order to correct this bending, exposure was limited to a part of the panel surface, and while the exposed part was moved,
The inclination of the panel surface in the exposed area is controlled so that it is always parallel to the axis of the light source, thereby preventing the stripes from bending.

FIG. 3 shows the correction mechanism. A shadow mask is mounted on the inner surface of the panel 4 at a predetermined position, and a long linear light source 5 is attached to the panel 4 in the direction of the slotted aperture 2 formed in the shadow mask. The light source 5 is rotated by the motor 6, and in synchronization with this rotation, the shirt light source 7 is moved in the direction of the mirror axis of the panel 4. 7, the inner surface of the panel 4 is irradiated with a strip-shaped exposed portion 8 as shown in FIG. be exposed to light. Therefore, as the exposure section 8 moves, the slope of the marquee line of the light source 5 is changed so that the inclination of the panel surface on which the exposure section 8 is located and the axis of the light source 5 always maintain a parallel relationship. In this way, the stripe S formed on the panel surface 4 becomes approximately linear,
Bent shapes can be removed.

However, in the exposure method using this device, since the slit portion 7a of the shirt cover 7 is very narrow, the effective utilization rate of the light emitted by the light source 5 is significantly reduced, and the exposure time is therefore long, resulting in inefficiency. In this case, there is a drawback that a very large number of such exposure apparatuses are required.

The object of the present invention is to arrange the apertures 2 of the curved mask 1 along the intersection line formed by the intersection of the curved surface of the mask 1 and the plane created by the light source including the light emitting axis of the light source 5 having an elongated light emitting axis. It is an object of the present invention to provide a method for manufacturing a shadow mask that can form stripes without bends without using mechanical correction means such as an inclination of 5 and a mobile device of 7.

According to the present invention, a light source having a light emitting ball elongated in the short width (Y-axis) direction of a spherical shadow mask provided on the inner surface of a panel of a cathode ray tube is placed at the exposure center for forming crab light stripes, and the light emitting The plane created by Koto including the axis and the radius Rm
The intersection angle at a point on the spherical surface of the mask at a distance above the long axis (X-axis) from the center of the screen with a plane extending in the Y-axis direction that includes the center of curvature of the spherical mask is 8. When doing so, an original drawing is formed in which a row of slotted apertures that are continuous in the Y-axis direction via a bridge is arranged along an approximate aperture arrangement line that satisfies the relationship of the following equation, and the original drawing is attached to a metal flat plate. A method for manufacturing a shadow mask is obtained, which is characterized in that the metal plate is transferred to form a slotted aperture, and then the metal flat plate is formed into a spherical mask with a radius Rm.

Enemy Rm thing -

FIG. 5 is a diagram illustrating the arrangement of slotted apertures 2 formed in the shadow mask of a color cathode ray tube according to the present invention. In this example, the shadow mask has a spherical shape.

In this invention, among the light emitted from the light source 5, a line of intersection 1 made by a plane 10 made by Koto, which forms a forehead angle Q, and a surface of the shadow mask 1, is emitted from the exposure center (Z axis).
3 along which an aperture 2 is formed.

Here, to explain the arrangement of the secondary slotted apertures 2, conventionally, the apertures 2 are arranged along a straight line while the shadow mask plate is still in a flat state, and after the apertures 2 are formed, the plate is formed into a spherical surface. That's what I do.

Therefore, as shown in FIG. 5, the arrangement of the apertures 2 on the spherical surface is on the line 12 formed by the surface 11 passing through the spherical center point 15 and the shadow mask. This line of intersection 12 lies on the great circle 12, which is well known in geography. If the plane 11 forming this great circle 12 forms an opening angle of 3, for example, with the exposure center axis Z-axis, then the two planes 10 and 11
When two planes share an arbitrary '1 point 14 on the spherical mask, if that point 14 is expressed as Pm (phantom m, kem, zm), Q, 6 becomes the following equation. Q = Side I (Toshi)
m 3 = n' (poisonous damage;) [2} When the graph of the mask sphere is expressed as the following equation, m is given from the center coordinates of the sphere.

10〆10(z+m)2:Rm2 The slope of the glue and light east face 10 is given by the formula [1}, and is given by the following formula.

Zm [4, Z = Kotobukiichi X
Furthermore, the plane 11 that creates the great circle 12 is a plane that passes through the center of the sphere 15, which is determined from the equation (2).

Zm+m ■Z =---
×-m Therefore, the angle 8 between the intersection line 13 and the x-axis in the vicinity of one point pm on the intersection line 13 of the Koto plane 10 and the spherical Masku (see Figure 6) is given by the {3} formula [4} From the slope of the intersection graph obtained from the formula, the following formula is obtained.

8, knee n one, (×m2 10zm (zm+m))
6, Desired.

Therefore, 82:-n-. (phantom m20 (zm+ma)
[7} From the skin-to-skin result, 0, and 82 are illusions.
≠0, that is, as shown in FIG. 5, the stripe image S projected by the aperture 2 formed along the conventional aperture array line 12 is parallel to the intersection line 13,
Therefore, since the light beams passing through the conventional aperture 2 are not continuous, the exposed stripes S are not continuous at all.

Therefore, according to the method using the correction mechanism shown in FIG.
The angle formed by the aperture array line 12 of such a mask is 0
2, in order to align the angle 8 formed by the Koto plane 10, by tilting the elongated light source 5 around the x-axis in FIG. The aperture array line 12 forms an angle 8 with the axis at a point m
The stripes are made to continue smoothly in the vicinity of m, matching the angle a2 formed with the x-axis.

On the other hand, the shadow mask according to the present invention has a light east plane 10
Since the apertures 2 are arranged on the intersection line 13 of the spherical mask 1 and the spherical mask 1, the angle 8 formed by the image coincides with the angle 82 formed by the apertures 2.

Therefore, even though the light beam passes through the aperture, it is included in the light beam plane 10, so the light projected by the face inner surface 4 is on the intersection line of the light flux plane 10 and the face inner surface 4, and the exposed stripe S is , continues smoothly on this intersection line. Thus, according to the present invention, by arranging the apertures 2 having such array lines 13 in the mask 1, it is possible to eliminate the inefficiency and complexity of mechanically performing geometric optical correction as explained in FIG. 3, which has been conventionally used. It is possible to provide smooth continuous stripes without using a device with a complex structure.

Moreover, an exposure method is used that does not require an exposure device having movable parts such as a light source tilting mechanism and a movement mechanism for the shirt cover 7, and there is no reduction in the light utilization rate due to the narrow slit 7a of the shirt cover 7. Because it can be used, it is highly efficient, and because it requires inexpensive equipment that does not require various mechanisms, the number of units installed during mass production can be extremely reduced.Furthermore, the low price of exposure equipment means that equipment costs can be reduced. This has a significant effect on the product and helps reduce the product price. Furthermore, by making the aperture 2 have a curved array according to the present invention, the exposed stripes are corrected in units of one pitch of the aperture 2, so that they are more accurate than stripes produced by an exposure method in which the exposure area is limited by the shutter opening. The precision is dramatically improved, and it is possible to provide a crab light screen with a better stripe shape, which in particular improves the quality of black stripe type color cathode ray tubes. Currently, the commonly used mask plate manufacturing method is to transfer an original pattern of apertures onto a continuous flat metal plate using photo printing technology, and then create apertures using a chemical treatment method.

Therefore, an important problem in implementing the present invention is to create an original pattern for arranging the apertures according to the present invention on the spherical surface of the mask. Therefore, the point 22 cutting the x-axis of the aperture array line 19 on the spherical mask shown in FIG.
xmo, 0, zmo), the great circle 18 created by the plane parallel to the y-axis passing through pmo is the circumference of the point pmo from point 23 on the spherical surface of the formed spherical mask center axis (z-axis). If the upper length is Xo, then a straight line 18 on the flat mask passes through a point 22'' located at a distance of Xo on the x axis from the origin 23^ of the mask plate 1, as shown in FIG.

The aperture array line 19 according to the present invention, which is very close to the great circle 18, is approximately equal to the line 21 projected on the tangential cylindrical surface of the great circle 18 in FIG.

When the cylindrical surface 20 including the line 21 is developed on the XY coordinates as shown in FIG. 9, a straight line 18 which is the great circle 18 on the spherical surface
The array line 21r is determined by determining the distance in X and Y from one point p' on the aperture array line 21^ to the one point p on the aperture array line 21^. Therefore, great circle 1 passing through pmo
When defining a cylindrical surface with conductor 8 as a new coordinate system sphere 'y'z' as shown in Figure 8, the great circle 18 is placed on the x'y' plane, the center of curvature is the coordinate origin, and the point Let pmo be on x ball.

Now, in FIG. 7, a plane 16 including the great circle 18 and a light east plane 17 including the aperture array line 19 according to the present invention.
If the angle formed by is 8, the two planes 16 and 17 each form an angle Q8 with the z-axis, resulting in an 8' quadratic equation.

0=B-Q ■Here, Q and 8 are given as values on the spherical surface by the '1' formula [2}, so it becomes an 8'-order formula.

8 = Ne n - 1 (Rm 2 1 m vote x Tsurugi 21 x m〆) '9
) Therefore, in the coordinate system of Fig. 8, aperture array line 2
Since the great circle 18' is included in the 0) point 22'
Therefore, the Koto plane 17' is Xy'z
′ coordinate system, it is given by the following equation.

Z'=-tan8・X'0Rmtan8
00Here, since the radius of the conducting wire is Rm, its graph becomes the following equation.

x12 +y12=Rm2 (11
) If one point on this conducting wire is p', and the intersection of the generatrix passing through this point and the aperture array line 21' according to the present invention is p, then the distance pP from p' to p is the z' value, which is the value of P. If the coordinates are (x'y'), the 'IQ equation gives the following relationship.

pp'knee tan8 x'10Rm is na (12)
When the cylindrical surface 20 is developed on the mask flat plate, the developed conductive wire 18'' as shown in FIG. 9 is as described above (fu, 0).
Since it passes through, the X coordinate of point p becomes the following equation from equation (12).

×=×.

1PP Nifuten nOx'-Rmtan8 (13
) The Y coordinate of point p is the point 22' that cuts the x' axis of the conductor 18'.
It is the length on the circumference from p' to p', and is expressed by the following formula.

Y: RmSin-I theory (14) Here, x'y' obtained from equations (13) and (14) is point p' on the conductor line in Figure 8, so point p(XY) is calculated by the following equation. It becomes a relational expression.

〆-Rmnena-X reverse ten (Sin boiled) 2=・(15)R
m2 tan20, that is, the graph expressed by equation (15) is the aperture array line on the mask slope according to the present invention.

However, tana is given by formula [9}, but Xmo,
The relationship between the f and the circumferential length of the point pmo on the x-axis in FIG.

Blood = RmSin (magazine) (16) For example, the radius of curvature of the spherical mask Rm = 80. The distance from the light source to the center of the spherical mask is m = 535, and the point where the aperture array line cuts the x axis is F = 190 ribs. When the aperture array line is found, the following graph is obtained from equations (15) and (17).

Poisonous Poison Tatsumi Hoshokan Ju Si〆 (Poison.

)=1 (18) Next, if we examine the error relationship between the approximate aperture array line 21'' and the true array line 19 expressed by equation (18) within the range of the effective mask surface, we can see that the two array lines are Since it is included in the east plane 17, the error is 6X.
is the following formula. 6X=L-Rmtan-・(poison) (,
9) However, L is the maximum value from the great circle 18 to the approximate aperture array line 21 on the cylindrical surface.

The effective surface of the mask is as follows. Since the point where lflSI9仇嬬IYISI4仇吇L takes the maximum is Xo=190 feet and Y=140 sails, the value of X at this time is the following value.

Since X = 184.4 kalpas, L is L = 190 - 184.49 = 5.51 sails (
20) The error is obtained from the values of equations (19) and (20).

6X215, 5I column-8 Misaki n-・(ship) l≦〇. Therefore, the error is less than 0.01 square, and the approximate aperture array line 21'' can be regarded as an expansion of the true aperture array line 19 in practice.

Regarding the aperture array line according to the present invention, the mask curved surface is a spherical surface. However, even when the mask has a general curved surface, the stripes can be smoothly continuous by arranging the apertures on the intersection line of the Koto plane and the mask curved surface. can.

[Brief explanation of the drawing]

Figure 1 is a perspective view showing an example of a shadow mask used in a black stripe type color cathode ray tube, and Figure 2 is a perspective view showing an example of a shadow mask used in a black stripe type color cathode ray tube.
Front view showing the shape of crab light stripes or black stripes formed by an uncorrected light source, 3rd
FIG. 4 is a perspective view showing the exposure relationship using a conventional correction device, FIG. 4 is a front view illustrating the secondary exposure method, and FIG. 5 is a perspective view illustrating the aperture array line according to the present invention. 6 is an enlarged plan view showing the relationship between a conventional aperture and a projected image, and FIG. 7 is an explanation of a method of developing aperture array lines on a spherical surface to perform aperture array according to the present invention. 8 is an explanatory diagram using a coordinate system converted to simplify the development method in FIG. 7, and FIG. 9 is an explanatory diagram of aperture array lines on a mask slope constructed according to the present invention. . 1: Shadow Mask, 2: Slots Door/Gucha,
3: bridge portion, 4: panel, 5: light source with an elongated optical axis, 12, 19: array line of slotted apertures used in the color cathode ray tube according to the present invention, 13: array line of slotted apertures of slave, 10, 17: Plane created by Koto including the light emission axis of the light source. Figure 2 Figure 3 Figure 5 Figure 6 Figure 7 Figure 8 Tsutomu? figure

Claims (1)

[Scope of Claims] 1. A light source having an emitting axis elongated in the short axis (Y-axis) direction of a spherical shadow mask provided on the inner surface of the panel of a cathode ray tube is placed at the center of exposure for forming phosphor stripes, and the light emitting A plane formed by the light beam including the axis, and a plane extending in the Y-axis direction including the center of curvature of the spherical mask with radius Rm,
When the intersection angle at a point on the spherical surface of the mask at a distance of X_0 on the long axis (X axis) from the center of the screen is θ,
An original drawing of approximate apertures that satisfies the relationship of the following equation is formed, in which the apertures are arranged along the arrangement line, the original drawing is transferred to a metal flat plate to form a slotted aperture, and then the metal flat plate is transferred to a slotted aperture with a radius of Rm. A method for producing a shadow mask, characterized by forming it into a spherical mask. ((X+Rmtanθ-X_0)^2)/(Rm^2t
an^2θ)+(sinY/(Rm))^2=1