JPH08124491A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE: To make the rate of occurrence of moire phenomenon as small as possible and to make less conspicuous the fringes produced by the stripes of a shadow mask itself by making as small as possible the rate of interference between the fringes of the shadow mask and fringes produced by horizontal-scanning luminescent lines. CONSTITUTION: Of four slot hole lines L1 to L4 (portions indicated by diagonal lines) in an array M of slot holes in a shadow mask 8, a slot hole 7 of the second slot hole line L2 adjacent a slot hole 7 of the first slot hole line L1 is deviated vertically downward by 2/4 of a stripe pitch PV. A slot hole 7 of the third slot hole line L3 adjacent the slot hole 7 of the second slot hole line L2 is deviated upward and in the direction opposite to that of deviation of the former slot hole 7, by 1/4 of the stripe pitch PV. A fourth slot hole 7 adjacent the slot hole 7 of the line L3 is deviated downward and in the direction opposite to that of deviation of the slot hole 7 of the line L3 , by 2/4 of the stripe pitch PV, and a repeating pattern is formed at each of the four slot hole lines L1 to L4 . Since the arrangement of the slot hole lines L1 to L4 is discontinuous and has no regularity in displaying a color image, the rate of interference between the fringes of the shadow mask 8 and fringes produced by horizontal-scanning luminescent lines is made as small as possible so as to reduce the rate of occurrence of moire phenomenon.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a color cathode ray tube,
More specifically, the present invention relates to a color cathode ray tube equipped with a shadow mask in which a large number of vertically elongated slit-like holes are formed in a predetermined arrangement in the vertical and horizontal directions.

[0002]

2. Description of the Related Art For example, as shown in FIG. 2, a color cathode ray tube comprises a bulb 4 in which a neck 1, a funnel 2 and a face panel 3 are joined and integrated, and an electron gun 5 for irradiating an electron beam into the neck 1. On the other hand, a structure in which a fluorescent film 6 is formed on the inner surface of the face panel 3 and a shadow mask 8 having a large number of through holes 7 formed between the electron gun 5 and the fluorescent film 6 is arranged. It is common.

The in-line type electron gun 5 shown in FIG. 2 irradiates three electron beams of a center beam G and a pair of side beams R and B passing on a horizontal plane including the bulb tube axis, and also fluorescent light. The film 6 is formed by vertically forming three vertically long stripe-shaped phosphors (not shown). Corresponding to this, the shadow mask 8 has vertically long slit-shaped through holes 7 vertically and horizontally. Many are formed according to the arrangement relationship of.

The electron beam emitted from the electron gun 5 is vertically and horizontally deflected by a magnetic field generated by a deflection yoke 9 mounted on the outer periphery of the funnel 2, passes through each through hole 7 of the shadow mask 8, and then faces. After reaching the fluorescent film 6 on the inner surface of the panel 2 and scanning the fluorescent film 6, the center beam G of the electron beam and the side beams R and B of the electron beam emit striped phosphors of corresponding colors to emit a desired color. Display an image.

As shown in FIG. 3, the shadow mask 8 used in the color cathode ray tube constructed as described above has slit-shaped through holes 7 [vertical length m] at a constant stripe pitch P _V in the vertical direction. having a through hole group M which are arranged in the horizontal direction with a hole row L arranged at regular intervals P _H. In this shadow mask 8, in order to secure the mechanical strength, one through hole row L and a through hole row L adjacent thereto have both through holes 7 in the vertical direction by ½ stripe pitch P _V. They are arranged in a staggered manner. As a result, every other through hole row L has the through holes 7 arranged in parallel with the horizontal direction. A bridge 10 [vertical length n] is formed between the through holes 7 arranged in the vertical direction of each through hole row L.

[0006]

By the way, in the color cathode ray tube, horizontal scanning of the electron beam causes a large number of horizontal scanning bright lines lined up in the vertical direction to appear on the face panel screen, and the horizontal scanning bright lines represent the bright portion, Bright and dark stripes are formed with a dark portion between each horizontal scanning bright line. On the other hand, in the shadow mask 8 through which the electron beam is transmitted, the bridge 10 located between the through holes 7 of each through hole row L is set between the two through hole rows L adjacent to each other.
Since it has a regularity that is shifted by a / 2 stripe pitch P _V, bright and dark stripes are generated by the through holes 7 and the bridge 10. As a result, the moire phenomenon occurs due to the interference between the bright and dark fringes of the shadow mask 8 and the bright and dark fringes of the horizontal scanning bright line.

On the other hand, in addition to the moire phenomenon, bright and dark stripes may appear on the screen due to the stripe pattern of the arrangement of the through holes 7 and the bridges 10 of the shadow mask 8 itself. That is, as described above, in the shadow mask 8, one through-hole row L and a through-hole row L adjacent to the certain through-hole row L are used as the through-holes 7 of both.
Are arranged so as to be vertically shifted by a 1/2 stripe pitch P _{V, since} the shift direction of the through holes 7 is directed in one direction, the bridges 10 formed between the through holes 7 are arranged.
As for, also, they are regularly arranged in a state of being displaced in one direction. As a result, when the shadow mask 8 is viewed from a certain direction, a striped pattern occurs in the entire shadow mask 8 because the directionality of displacement of the through holes 7 and the bridge 10 is uniform, and the striped pattern of the shadow mask 8 itself. As a result, bright and dark stripes appear on the screen.

Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to suppress the occurrence of the moire phenomenon as much as possible and at the same time conspicuous the bright and dark stripes due to the stripe pattern of the shadow mask itself. It is to provide a color cathode ray tube which can be eliminated.

[0009]

As a technical means for achieving the above object, the present invention provides a through hole row in which vertically long slit-like through holes are arranged at a predetermined stripe pitch in the vertical direction at predetermined intervals. A shadow mask having a group of through holes arranged in a horizontal direction, wherein the shadow mask is interposed between an electron gun for irradiating an electron beam and a fluorescent film having stripe-shaped phosphors formed on the inner surface of the face panel, In a color cathode ray tube in which an electron beam from an electron gun is deflected in horizontal and vertical directions and scanning is performed on a fluorescent film through a through hole of a shadow mask, the shadow mask is a first one of four through hole arrays. The through-holes of the second through-hole row are shifted in the vertical direction by 2/4 stripe pitch with respect to the through-holes of the through-hole row, and in the opposite direction to the through-holes of the second through-hole row. , Third The through holes of the through hole row are shifted by a 1/4 stripe pitch, and the through holes of the fourth through hole row are 2/4 stripes in the direction opposite to the shift direction with respect to the through holes of the third through hole row. It is characterized in that it has a through hole group in which a pattern is repeatedly formed for each of these four through hole rows by shifting the pitch.

In the present invention, it is desirable that the through holes of each through hole row be randomly arranged within a range of ± 1/16 stripe pitch from the designated position by a random number.

[0011]

In the color cathode ray tube according to the present invention, the through hole group of the shadow mask is formed in the repeating pattern for each of the above-mentioned four through hole rows, and the through holes of the adjacent through hole rows are
Since the array of the through holes is discontinuous and has no regularity by shifting in the vertical direction at a pitch of 4, 2/4, and 3/4 stripes, there is no regularity. The interference with the stripes can be suppressed as much as possible, and the occurrence of the moire phenomenon can be reduced.

Further, since the through holes are displaced while being inverted, the displacement direction is not directed in one direction. In this way, since the directionality of the displacement of the through holes and the bridge is not uniform, the stripe pattern becomes less noticeable in the entire shadow mask,
It is possible to reduce the bright and dark stripes appearing on the screen.

If the through holes of each of the through hole rows are randomly arranged within a range of ± 1/16 stripe pitch from the designated position by random numbers, the moire phenomenon is reduced and bright and dark stripes due to the stripe pattern of the shadow mask itself are formed. The reduction becomes even more remarkable.

[0014]

FIG. 1 shows an embodiment of a color cathode ray tube according to the present invention.
Will be described. The following embodiment is applied to the shadow mask 8 used in the color cathode ray tube of FIG. 2, and the same parts as those in FIG.

The feature of the present invention resides in the shadow mask 8 arranged between the electron gun 5 enclosed in the neck 1 of the bulb 4 and the fluorescent film 6 formed on the inner surface of the face panel 3. The through holes 7 forming the through hole group M are in an arrangement relationship.

[0016] Specifically, the shadow mask 8, hole rows arranged at regular stripe pitch P _V slits JoToruana 7 in the vertical direction as shown in FIG. 1 L ₁ ~L ₄ regular intervals P _H
Therefore, the through holes 7 in the adjacent through hole rows L _{1 to} L ₄ are provided with the through hole group M arranged in the horizontal direction, and based on the 1/4 stripe pitch P _V , 2/4, 3/4 The through hole rows L _{1 to} L ₄ are shifted in the vertical direction with the stripe pitch P _V being reversed. At this time, each through hole row L _{1 to} L
The vertical length n of the bridge 10 formed between the _four through holes 7 is a constant value.

Four through hole rows L ₁ through in the through hole group M
2/4 of the through holes 7 of the second through hole row L ₂ adjacent to the through holes 7 of the first through hole row L ₁ in L ₄ [hatched portion in the figure]
Shifted downward by vertically striped pitch P _V, with respect to the second hole row L ₂ of the through holes 7 upward opposite the shift direction, through holes of the third hole rows L ₃ adjacent 7 in 1 /
It is shifted by 4 stripe pitch P _V , and the through holes 7 of the adjacent fourth through hole row L ₄ are moved downwardly with respect to the through holes 7 of the third through hole row L ₃ in the downward direction in the direction opposite to the shift direction. The four stripes are shifted by a pitch P _V , and a repeating pattern is formed for each of these four through hole rows L _{1 to} L ₄ .

Incidentally, if the through holes 7 of the fourth through hole array L ₄ are displaced upward by 3/4 stripe pitch P _{V in the} direction opposite to the displacement direction, the next four through hole arrays L ₁ to The through holes 7 of the first through hole row L ₁ of L ₄ are located. Accordingly, the four holes columns L ₁ by forming a repeating pattern every ~L _4, holes 7 for each the four holes columns L ₁ ~L ₄
Will be parallel to the horizontal direction.

Although the arrangement relationship of the through holes 7 of the through hole rows L _{1 to} L ₄ has been described above, the arrangement relationship of the bridges 10 between the through holes 7 will be described below. When coordinates are set with the horizontal position of the bridge 10 of L ₁ as the origin O, Y of the bridge 10 of the first through hole array L ₁ is set.
The coordinates are 4 times the 1/4 stripe pitch P _v , the Y coordinate of the bridge 10 in the second through hole row L ₂ is 2 times the 1/4 stripe pitch P _v , and the bridge 10 in the third through hole row L ₃ . Is arranged at each position where the Y coordinate is 3 times the 1/4 stripe pitch P _v , and the Y coordinate of the bridge 10 of the fourth through hole row L ₄ is 1 times the 1/4 stripe pitch P _v .

In the color cathode ray tube using the shadow mask 8, the electron beam emitted from the electron gun 5 is deflected vertically and horizontally by the magnetic field generated by the deflection yoke 9, and passes through each through hole 7 of the shadow mask 8. Scanning is performed on the phosphor film 6 on the inner surface of the face panel 2 so that the center beam G and the side beams R and B of the electron beam cause the striped phosphors of the corresponding colors to emit light to display a desired color image.

At this time, in the shadow mask 8 of the present invention,
The through hole group M is formed in a repeating pattern for each of the _{four through} hole rows L _{1 to} L ₄ described above, and the adjacent through hole rows L _{1 to} L _{4 are formed.}
By shifting the through holes 7 in the vertical direction at a 1/4, 2/4, and 3/4 stripe pitch _Pv while shifting them, the array of the through hole rows L _{1 to} L ₄ becomes discontinuous and regular. Since it does not have, it is possible to suppress the interference between the bright and dark fringes of the shadow mask 8 and the bright and dark fringes due to the horizontal scanning bright line as much as possible, and reduce the occurrence of the moire phenomenon.

Further, since the through holes 7 are displaced while being inverted, the displacement direction is not oriented in one direction. In this way, the directionality of the displacement of the through holes 7 and the bridge 10 is not uniform, so that the stripe pattern becomes less noticeable in the entire shadow mask 8, and the bright and dark stripes appearing on the screen can be reduced.

Further, the through holes 7 of each of the through hole rows L _{1 to} L ₄ ,
That is, the bridges 10 located between the through holes 7 can be randomly arranged by the random number R _n within the range of ± 1/16 stripe pitch P _V from the specified position Y ₀ described above. The position of the bridge 10 is set based on the equation.

Y = Y ₀ + (R _n −0.5) × (1/16) In this way, the bridge 10 between the through holes 7 is ± 1/16 stripe pitch P _V from the designated position Y _0. By randomly arranging by the random number R _n within the range of, the reduction of the moire phenomenon and the reduction of the bright and dark fringes due to the striped pattern of the shadow mask 8 itself become more remarkable.

[0025]

According to the present invention, the occurrence of the moire phenomenon can be reduced by suppressing the interference between the bright and dark fringes of the shadow mask and the bright and dark fringes of the horizontal scanning bright lines as much as possible, and at the same time, The striped pattern appearing on the shadow mask itself becomes inconspicuous, and the bright and dark stripes appearing on the screen can be reduced. As a result, it is possible to provide a high-quality color cathode ray tube capable of realizing a good screen, and its practical value is great.

[Brief description of drawings]

FIG. 1 is an enlarged partial plan view showing a through hole group of a shadow mask incorporated in a color cathode ray tube for explaining an embodiment of a color cathode ray tube of the present invention.

FIG. 2 is a sectional view showing a specific structural example of a color cathode ray tube.

FIG. 3 is an enlarged partial plan view showing a through hole group of a shadow mask in a conventional color cathode ray tube.

[Explanation of symbols]

5 electron gun 6 fluorescent film 7 through hole 8 shadow mask L _{1 to} L ₄ through hole array P _V stripe pitch M through hole group

Front page continuation (72) Inventor Nobumitsu Aihara 2-9-1 Harashirashi, Otsu City, Shiga Kansai Nihon Electric Co., Ltd.

Claims (2)

[Claims] 1. A shadow mask having a through-hole group in which vertically elongated slit-like through holes are arranged in a horizontal direction at predetermined intervals in a vertical direction with a predetermined stripe pitch, and a shadow mask is provided, and an electron beam is irradiated. The shadow mask is interposed between the electron gun and the phosphor film having the stripe-shaped phosphor formed on the inner surface of the face panel, and the electron beam from the electron gun is deflected in the horizontal and vertical directions, and the through hole of the shadow mask is formed. In the color cathode ray tube that scans on the fluorescent film via the shadow mask, the shadow mask has two through holes in the second through hole row with respect to two through holes in the first through hole row among the four through hole rows. / 4 stripe pitch is vertically shifted, and the through holes of the third through hole row are shifted by ¼ stripe pitch in the direction opposite to the shift direction with respect to the through holes of the second through hole row. Third
The through-holes of the fourth through-hole row are shifted by 2/4 stripe pitch in the direction opposite to the displacement direction of the through-hole rows, and a transparent pattern is formed for each of these four through-hole rows. A color cathode ray tube having a group of holes. 2. The color cathode ray tube according to claim 1, wherein the through holes of each of the through hole rows are randomly arranged within a range of ± 1/16 stripe pitch from the designated position by a random number.