KR100505863B1 - Shadowmask of Color CRT - Google Patents

Abstract

The present invention relates to a color cathode ray tube, and in particular, to increase the rate of change of the vertical pitch between electron beam passing holes according to the position of the effective surface in the short axis direction by 4% to 12% and in the diagonal axis direction by 3% to 10%. The present invention relates to a cathode ray tube that prevents moiré phenomena and improves purity characteristics.

The technical means of the present invention includes a panel having a phosphor screen on an inner surface, a funnel connected to the panel, an electron gun mounted to a neck portion of the funnel to emit an electron beam toward the phosphor screen, and a phosphor screen on the inner surface of the panel. A color cathode ray tube including a shadow mask arranged at a predetermined interval with respect to color, wherein the shadow mask is rectangular having a long axis and a short axis, and has an effective surface including a plurality of electron beam through holes and the effective surface. An enclosed ineffective surface, the vertical pitch of said electron beam through holes being greater than 0.15 mm and less than 0.35 mm; The vertical pitch of the electron beam through-holes is increased in the shorter direction from the center portion.

Description

Shadow mask for color cathode ray tube {Shadowmask of Color CRT}

The present invention is to implement a shadow mask having a vertical pitch that satisfies the moiré and purity characteristics at the same time, the conventional shadow mask vertical pitch design has a single pitch on the short axis with respect to the center portion and gradually tilt toward the long axis It is designed with decreasing pitch for the design.

In general color cathode ray tube, as shown in FIG. 1, R, G, B phosphor screens 4 are coated on the inner surface, and explosion-proof glass is fixed on the front part, and the rear end of the panel. A funnel (2) fused to each other, an electron gun inserted into the neck portion of the funnel to emit an electron beam (6), a deflection yoke (5) for deflecting the electron beam (6), and a predetermined distance inside the panel A shadow mask (3) having a plurality of holes formed therethrough so as to pass the electron beam, a frame (7) for holding and supporting the shadow mask so as to maintain a predetermined distance from the inner surface of the panel, and a spring (8); Inner shield (9) for shielding the cathode ray tube is less affected by the external geomagnetic, and a reinforcing band (11) installed around the side of the panel to prevent external impact.

In addition, there is a magnet (10) for correcting the trajectory of the electron beam so as to strike the predetermined phosphor accurately to prevent poor color purity.

Figure 2 shows the structure of a conventional shadow mask, PVo is a vertical pitch between the electron beam through hole (3a) in the center, PVc is a vertical pitch between the electron beam through hole at the end of the diagonal axis, PVe is an electron beam through hole at the end of the long axis It is vertical pitch of the liver, and PVt is the vertical pitch of electron beam through hole at the short axis end. The conventional shadow mask structure has the same PVo, PVc, PVe, and PVt or a difference of about 1% to 3%.

In the conventional screen, the phosphor screen 4 is formed on the rear surface 12 of the face plate, and as shown in FIG. 3, a plurality of stripe or dot-shaped phosphors having a predetermined arrangement structure ( R, G, B) and a light absorbing material such as a black coating 41 between the respective phosphors. In addition, the rear surface 12 has an aluminum thin film layer 42 formed as a conductive film layer to increase luminance of the phosphor screen 4, to prevent ion damage of the phosphor screen 4, and to prevent potential drop of the phosphor screen 4. Done.

At this time, in the phosphors R, G, and B applied to the screen as shown in Fig. 4, the distance between G and G (or R to R) in the major axis direction is determined by the horizontal pitch of the phosphor screen 4 ( SP), the distance between G and G (or R to R) in the short axis direction is referred to as the vertical pitch SW of the phosphor screen 4.

On the other hand, the vertical pitch (PV) of the shadow mask (3) is closely related to the moiré characteristic, which is an important characteristic of the cathode ray tube, in addition to affects the purity characteristics and shadow mask (3) strength.

The main factors that cause moiré phenomenon in cathode ray tube can be divided into factors affecting moiré wavelength and intensity. Factors affecting the moiré wavelength are the scanning line spacing of the electron beam and the vertical pitch of the shadow mask, and the spot size of the electron gun affects the moire intensity. The moire wavelength ≤ is calculated by the following equation.

Where S is the electron beam scanning line spacing, PV is the vertical pitch of the electron beam through hole, and N is an integer.

In addition, the formula for calculating the moire intensity (M) is as follows.

Where k (PV) is a constant determined by PV, A is a proportionality constant, and D is the spot size of the electron beam.

Since the moiré wavelength is best distinguished when 4 mm to 10 mm, the vertical pitch of the electron beam through hole should be determined so that the moiré wavelength does not fall within the above range. In addition, as the moire intensity value is larger, the moire phenomenon is more likely to occur, so it is better to make the moire intensity value smaller.

However, in case of cathode ray tube, scanning line spacing is different according to modes (640 × 480, 800 × 600, 1024 × 768, 1280 × 1024). Conventional shadow mask vertical pitch has a small change rate of 1% to 3% at the center. Therefore, it is impossible to adjust the vertical pitch so that the moire wavelength is 4 mm or less in each mode.

In addition, the moiré intensity can be prevented by the vertical pitch according to the spot size because the electron beam spot size is different for each position as shown in the above formula, but the conventional vertical pitch change rate is not possible.

In addition, looking at the moire characteristics, the relationship between the purity characteristics and the shadow mask vertical pitch, the moire characteristics are advantageous the smaller the vertical pitch, while the purity characteristics are advantageous the larger the vertical pitch.

On the other hand, Korean Patent Publication No. 97-3365 is formed so that the vertical pitch of the shadow mask gradually increases from the central portion to the short axis direction, and gradually decreases from the central portion to the major axis direction, and in Korean Patent Publication No. 99-27074, the vertical pitch of the shadow mask is It is formed to increase as the center goes to the outer part of the shadow mask.

However, conventional vertical pitch design techniques have been designed around moiré characteristics, which has been a problem for purity characteristics.

Accordingly, an object of the present invention is to implement a shadow mask design specification that simultaneously satisfies moiré and purity characteristics.

The present invention is designed to achieve the above object, a panel having a phosphor screen on the inner surface, a funnel connected to the panel, an electron gun mounted on the neck portion of the funnel and emits an electron beam toward the phosphor screen, the panel A color cathode ray tube including a shadow mask arranged at a predetermined interval with respect to an inner phosphor screen and serving as color screening, wherein the shadow mask is rectangular having a long axis and a short axis, and has an effective surface including a plurality of electron beam through holes. And an invalid surface surrounding the effective surface, wherein the vertical pitch of the electron beam through hole is larger than 0.15 mm and smaller than 0.35 mm; The vertical pitch of the electron beam through-holes is increased in the shorter direction from the center portion.

As a second technical solution, there is provided a panel having a phosphor screen on the inner surface, a funnel connected to the panel, an electron gun mounted on the neck portion of the funnel and emitting an electron beam toward the phosphor screen, and a phosphor on the inner surface of the panel. A color cathode ray tube including a shadow mask arranged at a predetermined interval with respect to a screen, and serving as color screening, wherein the shadow mask is rectangular having a long axis and a short axis, and has an effective surface including a plurality of electron beam through holes and the effective area. An invalid surface surrounding the surface, wherein the vertical pitch of the electron beam through hole is larger than 0.15 mm and smaller than 0.35 mm; The vertical pitch of the electron beam through-holes is increased in the direction of the diagonal axis from the center portion.

As a third technical solution, a panel having a phosphor screen on an inner surface, a funnel connected to the panel, an electron gun mounted on a neck portion of the funnel and emitting an electron beam toward the phosphor screen, and a phosphor on the inner surface of the panel. A color cathode ray tube including a shadow mask arranged at a predetermined interval with respect to a screen, and serving as color screening, wherein the shadow mask is rectangular having a long axis and a short axis, and has an effective surface including a plurality of electron beam through holes and the effective area. An invalid surface surrounding the surface, wherein the vertical pitch of the electron beam through hole is larger than 0.15 mm and smaller than 0.35 mm; The vertical pitch of the electron beam passing hole in the center portion of the shadow mask is smaller than the vertical pitch of the electron beam passing hole in the short end portion of the shadow mask and smaller than the vertical pitch of the diagonal axis end portion of the shadow mask.

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

In general, as shown in FIG. 2, the shadow mask 3 has two long axis planes x horizontally and two short axis planes y vertically in a rectangular shape. The two horizontal long axes may be referred to as long sides, and the two vertical short axes may be referred to as short sides. The major axis x is parallel to the central major axis of the shadow mask and the minor axis y is parallel to the minor axis of the shadow mask.

In the shadow mask 3, the electron beam passing holes 3a are arranged vertically in rows and horizontally in rows. The electron beam through holes 3a in one row are in a different column than the electron beam through holes 3a in adjacent rows. The vertical spacing between the electron beam through holes in the same row is the vertical pitch PV of the electron beam through holes and the horizontal spacing between the electron beam through holes in the same column is the horizontal pitch PH of the electron beam through holes.

The vertical pitch PV of the shadow mask of the technique according to the present invention has an electron beam through hole vertical pitch PV in the center of the shadow mask 3 being larger than 0.15 mm and smaller than 0.35 mm; The vertical pitch PV of the electron beam passing hole increases in a short axis direction from the center portion.

Y / X (mm) 0.00 30.00 60.00 90.00 120.00 150.00 170.00 177.35 180.00 0.00 0.260 0.260 0.259 0.259 0.258 0.257 0.256 0.255 0.255 25.00 0.260 0.260 0.260 0.259 0.258 0.257 0.256 0.256 0.256 50.00 0.262 0.262 0.261 0.261 0.260 0.259 0.258 0.257 0.257 75.00 0.264 0.264 0.264 0.263 0.262 0.261 0.260 0.260 0.260 100.00 0.268 0.268 0.267 0.267 0.266 0.265 0.264 0.264 0.263 125.00 0.274 0.274 0.274 0.273 0.272 0.271 0.271 0.270 0.270 133.15 0.276 0.276 0.276 0.275 0.274 0.273 0.272 0.272 0.272 135.00 0.276 0.276 0.276 0.275 0.275 0.274 0.273 0.272 0.272

TABLE 2 Shadow mask vertical pitch of a 19 "monitor cathode ray tube according to the present invention.

Table 2 shows an example of the vertical pitch of the shadow mask according to the present invention, wherein the vertical pitch of the center electron beam passing space is 0.2 mm to 0.3 mm.

That is, as shown in FIG. 5, the vertical pitch PV of the electron beam passing hole 3a increases from 4% to 12% of the vertical pitch PV of the central electron beam passing hole as it goes from the central portion to the short axis end. The vertical pitch (PVt) of the electron beam through hole was increased by 3% to 10% of the vertical pitch of the central electron beam through hole.

Therefore, when the vertical pitch of the central electron beam through hole is referred to as PVo, the vertical pitch of the single axis end electron beam through hole is referred to as PVt, and the vertical pitch of the diagonal axis end electron beam through hole is referred to as PVc. (2) is satisfied.

1.04PVo ≤ PVt ≤ 1.12PVo --------------- (Equation 1)

1.03PVo ≤ PVc ≤ 1.1PVo --------------- (Equation 2)

In addition, the vertical pitch PV of the central electron beam through hole was greater than or equal to 0.2 mm and smaller than or equal to 0.3 mm. If the vertical pitch (PVo) between the center electron beam through holes is smaller than 0.2 mm, the gap between the shadow mask hole and the hole is too small, so it is vulnerable to mask clogging defects, and there is a high possibility of coating mixed color defects, and the purity margin gap is too large. If the ICT productivity is reduced, and the vertical pitch PV is larger than 0.3 mm, the distance between the shadow mask 3 and the electron beam through hole 3a is too large, so that the resolution of the color monitor itself is increased. This is because the result is a decrease.

On the other hand, if the vertical pitch PVt of the electron beam through hole at the short end is increased to less than 4% of the vertical pitch of the central electron beam through hole, the productivity of ITC decreases for the same reason as when the vertical pitch is formed smaller than 0.2 mm. When the vertical pitch PVt of the electron beam through hole at the short end is increased by more than 12% of the vertical pitch of the central electron beam through hole, the resolution is lowered for the same reason as when the vertical pitch is formed larger than 0.3 mm.

In addition, the shadow mask 3 has a rectangular shape consisting of a long axis and a short axis, and comprises an effective surface including a plurality of electron beam passing holes 3a and an invalid surface surrounding the effective surface, and the electron beam passing holes 3a. The vertical pitch is larger than 0.15 mm, smaller than 0.35 mm, and the vertical pitch of the electron beam through-hole is increased from the center to the diagonal axis direction, and the vertical pitch of the electron beam through-hole PVc at the end of the diagonal axis is centered. It is preferable to increase 3% to 10% of the vertical pitch PV of the electron beam passing hole.

This means that when the vertical pitch PVc of the electron beam passing hole at the end of the diagonal axis is increased to less than 3% and more than 10% of the vertical pitch of the central electron beam passing hole, the vertical pitch PVt of the electron beam passing hole at the short end is passed through the center electron beam. Problems such as increasing less than 4% and more than 12% of the vertical pitch of the ball appear.

Further, preferably, the vertical pitch PV of the electron beam through hole 3a of the shadow mask is reduced to decrease in the long axis direction PVe from the central portion PVo.

On the other hand, the horizontal pitch (PH) of the shadow mask satisfies the following (Equation 3).

0.3 mm ≤ PH ≤ 0.6 mm --------------- (Equation 3)

In other words, when the horizontal pitch PH is smaller than 0.3 mm, the distance between the electron beam through holes 3a in the shadow mask is narrowed, which reduces the electron beam margin, which adversely affects the purity. The spacing between the electron beam passing holes is too far away, resulting in a drop in resolution.

In addition, the horizontal pitch PH of the electron beam passing hole 3a should be increased from the central portion PHo toward the major axis direction PHe.

The electron beam 6 is scanned by the phosphors R, G, and B formed on the screen by passing through the electron beam passing holes 3a of the shadow mask 3, and the horizontal pitch between the electron beam passing holes of the shadow mask (PH) ) And the vertical pitch PV also change the horizontal pitch SP and the vertical pitch SW of the screen phosphor 4.

Accordingly, it is preferable that the horizontal pitch SP of the screen phosphor satisfies the following formula (4) between the electron beam through holes 3a of the shadow mask.

PH ≤ SP ≤ 1.1PH --------------- (Equation 4)

In addition, the relationship between the vertical pitch (PV) of the shadow mask according to the present invention is that the outer surface is almost flat, the panel 1 having a predetermined curvature on the inner surface, the funnel 2 connected to the panel 1, and the funnel A shadow mask (3) mounted at a neck portion of the electron gun for emitting an electron beam (6) toward the phosphor screen (4) and arranged at a predetermined interval with respect to the phosphor screen (4) on the inner surface of the panel to serve as color screening (3). It is also applicable to a flat color cathode ray tube including), and by designing as described above to prevent moiré phenomenon and improve the purity characteristics.

The conventional electron beam through hole (3a) is formed of an electron beam through hole (Slot) type and a circular dot (Dot) type formed to be close to a square shape, according to the present invention, the shape of the electron beam through hole is a circle or a circle. It is characterized by a close shape.

Preferably, the vertical pitch of the electron beam through hole 3a is formed to be greater than or equal to 0.24 mm and less than or equal to 0.28 mm in the central portion PVo.

As such, those skilled in the art will appreciate that the present invention can be implemented in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative and not restrictive in all respects, and the scope of the present invention is indicated by the appended claims rather than the foregoing description, and the meaning and scope of the claims and All changes or modifications derived from the equivalent concept should be interpreted as being included in the scope of the present invention.

Therefore, according to the present invention, the vertical pitch between the electron beam passing hole of the shadow mask is increased from the central portion to the short axis end and increases from the central portion to the diagonal axis end, thereby satisfying not only the moire characteristic but also the purity characteristic at the same time. have.

1 is a cross-sectional view of a typical color cathode ray tube.

2 is a view showing the vertical pitch of the electron beam passing through the shadow mask.

3 is a diagram showing an electron beam passing hole and a phosphor screen of a shadow mask.

4 shows the horizontal and vertical pitch of phosphor screens.

5 is a view showing an embodiment of a shadow mask structure according to the present invention.

6 is a view showing a horizontal pitch of the electron beam passing through the shadow mask.

*** Explanation of symbols for the main parts of the drawing ***

1 panel 2 funnel

3: shadow mask 3a: electron beam passing hole

4: phosphor screen 6: electron beam

PH: Horizontal pitch PV: Vertical pitch

Claims (27)

A panel having a phosphor screen on an inner surface, a funnel connected to the panel, an electron gun mounted to a neck portion of the funnel to emit an electron beam toward the phosphor screen, and disposed at a predetermined interval with respect to the phosphor screen on the inner surface of the panel In the color cathode ray tube comprising a shadow mask that serves as color screening, The shadow mask has a rectangular shape consisting of a long axis and a short axis, and comprises an effective surface including a plurality of electron beam passing holes and an invalid surface surrounding the effective surface, and the vertical pitch of the electron beam passing holes is greater than or equal to 0.2 mm, Less than or equal to 0.35 mm, The vertical pitch of the electron beam through hole increases in the shorter direction from the center portion, The vertical pitch of the electron beam through hole increases in the direction of the diagonal axis from the center portion, The vertical pitch of the electron beam through-holes cathode tube, characterized in that to decrease in the direction of the long axis from the center. The method of claim 1, When the vertical pitch of the central electron beam through hole is called PVo, a cathode ray tube, characterized in that the following formula is satisfied. 0.2 mm ≤ PVo ≤ 0.3 mm The method of claim 1, And a vertical pitch of the single-ended tip electron beam passing hole is referred to as PVt and a central electron beam passing hole is referred to as PVo. 1.04PVo ≤ PVt ≤ 1.12PVo (delete) (delete) The method of claim 1, And a vertical pitch of the diagonal beam-end electron beam through hole is referred to as PVc, and a central electron beam through hole is referred to as PVo. 1.03PVo ≤ PVc ≤ 1.1PVo  (delete) (delete) (delete) (delete) The method of claim 1, The horizontal pitch of the electron beam through-holes cathode tube, characterized in that increases in the direction of the long axis from the center portion. The method of claim 11, When the horizontal pitch of the electron beam through-hole PH is, the cathode tube characterized in that the following formula is satisfied. 0.3 mm ≤ PH ≤ 0.6 mm (delete) The method of claim 11, When the horizontal pitch of the screen is called SP, the horizontal pitch of the shadow mask, PH, Cathode ray tube characterized in that the following formula is satisfied. PH ≤ SP ≤ 1.1PH (delete) (delete) (delete) The method of claim 1, The horizontal pitch of the electron beam through-holes cathode tube, characterized in that increasing in the direction of the short axis or diagonal axis in the center. (delete) The method of claim 1, The panel is characterized in that the outer surface is almost flat, the inner surface has a predetermined curvature. The method of claim 1, Cathode ray tube, characterized in that the shape of the electron beam through hole is circular or elliptical. (delete) The method of claim 1, When the vertical pitch of the central electron beam through hole is called PVo, a cathode ray tube, characterized in that the following formula is satisfied. 0.24 mm ≤ PVo ≤ 0.28 mm (delete) (delete) (delete) (delete)