KR19980067807A - Shadow mask for color cathode ray tube - Google Patents

Abstract

A shadow mask for a color cathode ray tube is disclosed. In the shadow mask for color cathode ray tube according to the present invention, the pitch of the electron beam through hole formed in the center portion of the perforated portion, the 2/3 point portion and the corner portion from the center portion is 1 times, 1.2 to 1.3 times, and 1.1 times the set values, respectively. Characterized in that formed. By employing the present invention, since the non-uniform spacing of the electron beams generated according to the doming phenomenon is uniform, there is an effect of preventing the color bleeding phenomenon due to the doming phenomenon.

Description

Shadow mask for color cathode ray tube

The present invention relates to a shadow mask for a color cathode ray tube, and more particularly to a shadow mask for a color cathode ray tube having an improved structure of beam passing holes.

The color cathode ray tube 1 is provided with a shadow mask 2 attached to the frame inside the panel 5 as shown in FIG. 1. Although the role of the frame 3 supports the shadow mask 2, the role of compensating for the error distance by moving forward by the amount of expansion during thermal deformation of the shadow mask 2 is also very important. That is, when power is applied to the shadow mask 2, the shadow mask 2 is thermally expanded to generate a dominant phenomenon, and the landing mask of the electron beam is generated because the position of the shadow mask beam through hole is changed by the dominant phenomenon. By moving the frame 3 forward through the bimetal hook on the spring 6 which suspends the frame 3 on the inner circumference of the panel 5, the shadow mask is advanced to move the beam mask forward. The corrected beam through hole is located on a normal track to compensate for the thermal expansion of the shadow mask.

FIG. 2 illustrates a shadow mask employed in FIG. 1, and FIG. 3 is an enlarged view of a portion of the shadow mask.

The shadow mask 2 is composed of a main body through which the electron beam passes, that is, a hole 2b and beam passing holes 2a formed in the hole 2b. The hole 2b is arc-shaped, has a curvature R of a predetermined size, and the longitudinal length y of the hole 2b is smaller than the length 2z in the transverse direction but is formed at a constant ratio. For example, the shadow mask of a cathode ray tube used in general television has a length ratio of 4 to 3 in the lateral direction and a longitudinal direction, and a 16 to 9 wide vision produced by the screen ratio of a movie theater. In addition, by the method of corrosion applied photolithography, hundreds of thousands of beam through holes 2a were drilled on the surface to pass each electron beam through the beam through holes 2a.

Referring to FIG. 3, which shows a partial extract of the beam passing holes 2a formed in the hole 2b, the beam passing holes 2a have an elongated rectangular shape having a pitch p of the same size. It is formed at regular intervals t, and the arrangement is similarly formed at regular intervals.

However, when power is applied to the color cathode ray tube, the electron beam emitted from the electron gun is bent by the deflection yoke attached to the neck portion of the cathode ray tube, and only the electron beam that reaches the front of the shadow mask and passes through the beam passing hole is applied to the screen surface. Is injected. At this time, the electron beams that do not pass through the beam passing hole (2b) hits the shadow mask to generate heat and cause thermal deformation. Although the above-described spring is installed to compensate for this thermal deformation, the thermal mask of the shadow mask shown in FIG. 4 is shown because the complete compensation function of the shadow mask is not possible. According to this thermal deformation, the pitches of the electron beam through holes formed in the perforations 2b are different for each part of the shadow mask. The central root c of the shadow mask aperture maintains its original pitch, but has a larger gap from the center to the edge a) (a '). In the transverse direction of the shadow mask perforations, two-thirds (b ') at the center expand at 1.1 times the original pitch, and edges (a) (a') are 1.3 times larger. As the pitch of the beam passing holes for each part is changed, color bleeding from the fluorescent surface occurs. In other words, the electron beam emitted from the electron gun is bent by the deflection yoke and passes through the beam passing holes formed in the predetermined area of the shadow mask hole to impinge the fluorescent film for each color to express the color, but the beam passes for each area of the shadow mask hole. Since the pitches of the balls are different, they are incident at different angles than the predetermined angles and invade the fluorescent membranes of different colors. Therefore, mixed colors appear rather than the desired colors, and color bleeding occurs.

The present invention was created to solve the above problems, and provides a shadow mask for color cathode ray tube without color bleeding by improving its structure to prevent mislanding caused by non-uniform thermal deformation of each part of the shadow mask according to the ming phenomenon. Has its purpose.

1 is a cross-sectional view schematically showing a color cathode ray tube.

FIG. 2 is a front view schematically illustrating a shadow mask employed in the color cathode ray tube of FIG. 1.

FIG. 3 is an enlarged view schematically illustrating a portion of a beam passing hole of the shadow mask for a color cathode ray tube of FIG. 2.

FIG. 4 is a graph schematically showing the pitch of beam passing holes for each part of the shadow mask according to the ming phenomenon.

5 is a graph schematically showing the pitch of beam passing holes for each part of the shadow mask according to the present invention.

Figure 6 is a graph schematically showing the mutual spacing of the beam through-hole arrangement for each part of the shadow mask according to the present invention.

Explanation of symbols for the main parts of the drawings

1 ... color cathode line

2 ... shadow mask

3 ... frame

4.inner shield

5 ... panel

6.Spring

2a ... beam passing through

2b.

s ... mutual spacing of beam through-hole arrangements

t ... gap of beam passing holes

p .... pitch of beam passing hole

y ... longitudinal length

z ... lateral length

In order to achieve the above object, the shadow mask for color cathode ray tube according to the invention has a pitch of electron beam through holes formed at the center of the perforated part, the 2/3 point part and the corner part from the center part, respectively, from 1.2 to 1.2. 1.3 times, characterized in that formed by 1.1 times.

In another aspect, the array of electron beam through holes formed in the hole portion is formed in a stripe shape.

In still another aspect, the spacing between the arrays of electron beam through holes is preferably formed differently, and between the centers of the perforations and the arrays of electron beam through holes formed at 2/3 points and corners from the center. Is characterized in that formed by 1 times, 1.2 times to 1.3 times, 1.1 times the set value, respectively.

Hereinafter, exemplary embodiments of a shadow mask for a color cathode ray tube according to the present invention will be described in detail with reference to the accompanying drawings. 5 is a graph schematically showing the pitch of the beam through holes of the shadow mask according to the present invention, Figure 6 is a graph schematically showing the size of the mutual gap of the beam through hole arrangement of the shadow mask according to the present invention.

The perforated portion of the shadow mask according to the present invention has an arc shape having a predetermined curvature at the edge thereof, and has a shape almost close to a rectangle whose length in the longitudinal direction is smaller than the length in the transverse direction. The shadow mask is one of the most important parts of the color cathode ray tube, and the electron beam is allowed to pass through hundreds of thousands of beam passing holes on the surface by a method using corrosion by photolithography. The electron beam through holes of the hole are different in pitch for each part of the shadow mask hole. The center portion (c) of the shadow mask perforated portion maintains the original spacing, and the edge portion (a) (a ') of the perforated portion that grows to 1.3 times the pitch of the beam through hole formed in the center portion of the perforated portion at the time of doming It creates a pitch about 1.1 times the pitch of the beam through hole on the center of the hole. In addition, the 2/3 portion (b) (b '), which extends up to 1.1 times the pitch of the beam through hole formed in the center of the hole in the doming phenomenon, forms a pitch about 1.3 times the pitch of the hole through the hole in the center of the hole.

The operation of the shadow mask having the configuration as described above is as follows.

Power is applied to the color cathode ray tube, and the electron beam is emitted from the electron gun, and the emitted electron beam is bent at a predetermined interval by the deflection yoke, and passes through the beam passing holes of the shadow mask to impinge on the fluorescent film to express color. Since the electron beam passing through the beam passing holes is 15% to 18%, nearly 80% of the electron beams hit the shadow mask body and are lost as heat. Therefore, the shadow mask is thermally deformed, and the distance between the beam through holes of each part of the shadow mask is also different from each other, so that the predetermined angle of the electron beam is changed. Although the present invention is different from the pitch of the beam through holes formed in the perforations to maintain the pitch at a constant rate even when the heat deformation, the angle of irradiation of the electron beam passing through the beam through holes to hit a predetermined fluorescent film only Therefore, color bleeding can be prevented and stable color can be realized.

Shadow mask according to another embodiment of the present invention, as shown in FIG. The spacing of beam through holes in each part of the shadow mask hole was changed. The center portion (c) with almost no deformation maintains the arrangement interval of the original beam passing holes, and the edge (a) (a '), which is deformed up to 1.3 times the original arrangement interval, is formed at about 1.1 times. (b) (b ') in the transverse direction of the shadow mask perforation, which is deformed by 1.1 times the array spacing of the beam through holes in (c), is 1.3 of the beam spacing over the center of the perforation. The interval of about two times was maintained. As a result, beam through holes which form different arrangement intervals of each hole portion during thermal deformation of the shadow mask form different arrangements of mutual intervals at the time of manufacture so as to maintain uniform non-uniform thermal expansion according to the doming phenomenon. It is possible to maintain the irradiation angle of the electron beam by arranging the spaced beam passing holes.

The shadow mask for color cathode ray tube employing the above-mentioned beam through holes has the following effects.

First, the color bleeding phenomenon of the fluorescent film is prevented.

The shadow mask according to the present invention is to compensate the pitch of the beam through holes generated at the time of the dominant phenomenon differently for each part to prevent the color bleeding caused by the deviation of the electron beam. In other words, the pitch of the beam passing holes maintains the current state on the center of the hole, and the edge where the pitch deformation is large makes the gap about 1.1 times the pitch of the beam passing hole in the center of the hole. Two-thirds of the center is about 1.3 times the pitch of the beam through-holes in the center, so that even when the shadow mask is thermally deformed, it is evenly spaced. Therefore, since the irradiation angle of the electron beam for each part that hits the fluorescent film as a whole can be maintained at a stable angle, color bleeding is prevented because only the fluorescent film of a predetermined part is expressed to express color. In another embodiment, by varying the distance between the array of beam through holes in the shadow mask perforations to maintain the same ratio of irradiation angle during thermal deformation, color bleeding caused by hitting only a predetermined fluorescent film and overlapping with other fluorescent films It has the effect of preventing.

Second, the color cathode ray tube has stable luminance.

As described above, the shadow mask according to the present invention maintains the pitch of the beam passing holes for each part of the perforated part appropriately at the irradiation angle of the electron beam during thermal deformation of the shadow mask by changing the pitch of the beam passing holes per the perforated part. Since the electron beam hits only a predetermined fluorescent film to express color, color blur can be prevented, thereby having a stable luminance. In addition to the method of varying the pitch of the beam through holes for each part of the shadow mask hole, there is also a method of maintaining the irradiation angle of the electron beam by varying the mutual spacing of the arrangement of the beam through holes formed in the hole. In other words, the center of the perforated part with constant intervals between the beam through hole arrays is kept as it is, and the edge of the perforated part with severe deformation is formed at about 1.1 times the set value and the 2/3 part is 1.3 of the set value. Make a boat. In this way, by varying the arrangement interval of the beam through holes formed in the hole to maintain the irradiation angle of the electron beam as a whole during thermal deformation of the shadow mask, it is possible to prevent color bleeding and to achieve stable luminance.

Although the present invention has been described with reference to the embodiments shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (4)

The shadow mask for color cathode ray tube, characterized in that the pitch of the electron beam through hole formed in the center portion of the perforated portion, the 2/3 point portion and the corner portion from the center portion is formed to 1 times, 1.2 to 1.3 times, 1.1 times the set values, respectively. . The method of claim 1, The shadow mask for color cathode ray tube, characterized in that the array of electron beam through holes formed in the hole portion formed in a stripe shape. The method of claim 2, The shadow mask for color cathode ray tube, characterized in that the spacing between the arrangement of the electron beam through holes are different. The method of claim 3, For the color cathode ray tube, characterized in that between the center portion of the perforated portion, and the array of electron beam through holes formed at the 2/3 point portion and the corner portion from the center portion are formed to 1 times, 1.2 times to 1.3 times, 1.1 times the set values, respectively. Shadow mask.