JPH08124492A - Color cathode-ray tube - Google Patents

Abstract

PURPOSE: To provide a screen having a good contour with no unevenness at the vertical boundary plane of its effective screen by forming elongate holes by which slot holes(SH) touching the vertical boundary line of the effective screen area of the shadow mask are communicated with other slot holes located inside them, if the former slot holes have half or less of normal vertical length. CONSTITUTION: In an array M of slot holes in a shadow mask 8, the slot holes 7 touching the vertical boundary line C of an effective screen area (b) and each having half or less of normal vertical length (m) are communicated with other slot holes 7 located inside them, so as to form elongate slot holes 7'. The slot holes 7' are formed simultaneously with the other slot holes 7 during manufacture of the shadow mask 8. When the slot holes 7' are formed as to the slot holes 7 each having half or less of the normal length (m), the maximum length of each slot hole 7' is m+m/2+n.

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 including a shadow mask in which a large number of vertically elongated slot 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. 7, 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 slot holes 7 formed between the electron gun 5 and the fluorescent film 6 is arranged. It is common.

The electron gun 5 shown in FIG. 7 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 a fluorescent film 6 as well. Is three vertically elongated striped phosphors (not shown) formed in the vertical direction. On the other hand, the shadow mask 8 is formed with a large number of vertically elongated slot holes 7 corresponding to the fluorescent film 6 in a predetermined arrangement in the vertical and horizontal directions.

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 slot hole 7 of the shadow mask 8, and then faces. When reaching the fluorescent film 6 on the inner surface of the panel 2 and scanning the fluorescent film 6,
A center beam G and a side beam R of the electron beam,
B causes the striped phosphors of the corresponding colors to emit light to display a desired color image.

In the shadow mask 8 used in the color cathode ray tube constructed as described above, as shown in FIG. 8, the slot holes 7 each having a constant vertical length m have a constant stripe pitch P _V in the vertical direction. It has a slot hole group M in which the aligned row of slot holes L are arranged in the horizontal direction at a constant interval P _H. As a result, the bridge 1 having a constant vertical length n is provided between the slot holes 7 arranged in the vertical direction of each slot hole row L.
0 is formed.

The slot hole group M is arranged, for example, such that the slot holes 7 of the adjacent slot hole row L are vertically shifted by a ratio based on the stripe pitch P _V , or the slot holes 7 are arranged. The holes 7 are arranged randomly based on a random number. This allows
The slot hole 7 and the bridge 1 are formed by passing the electron beam.
The occurrence of the moire phenomenon due to the interference between the bright and dark fringes of the shadow mask 8 caused by 0 and the bright and dark fringes on the screen due to the horizontal scanning bright lines generated by the horizontal scanning of the electron beam is suppressed as much as possible. There is.

[0007]

By the way, in the shadow mask 8 used in the color cathode ray tube, for the slot hole group M, the slot holes 7 of the adjacent slot hole row L are arranged.
Since they are arranged in a state of being vertically displaced from each other, there are the following problems.

That is, as shown in FIG. 8, an effective screen area b is set in the shadow mask 8 in correspondence with an effective screen a [described later] on the face panel 3 of the color cathode ray tube. The slot hole group M is provided therein. Therefore, as described above, when the slot holes 7 of the slot hole row L in the slot hole group M are displaced in the vertical direction, the slot holes 7 in contact with the upper and lower boundary lines c of the effective screen area b are other than this. Some slot holes 7 do not have a constant vertical length m.

As described above, the slot hole 7 in contact with the upper and lower boundary lines c of the effective screen area b of the shadow mask 8 has a constant vertical length m, for example, half or less of the normal vertical length m. Otherwise, when the fluorescent film 6 is formed on the inner surface of the face panel 3, when the shadow mask 8 is used for the exposure process, the opening area of the slot holes 7 is smaller than that of the other slot holes 7, so that portion is not formed. When the color image is displayed on the face panel 3 by the fluorescent film 6 formed by this, the upper and lower boundary portions d of the effective screen a of the face panel 3 are displayed as shown in FIG. The unevenness e appears, and it is difficult to obtain an image having a good contour due to the unevenness e.

Therefore, the present invention has been proposed in view of the above problems, and an object of the present invention is to provide an image with a good contour without causing unevenness at the upper and lower boundaries of the effective screen of the face panel. It is to provide a color cathode ray tube capable of obtaining

[0011]

As a technical means for achieving the above object, the present invention provides a horizontal slot hole row in which a plurality of vertically elongated slot holes having a predetermined vertical length are arranged in the vertical direction. A shadow mask having a group of slot holes arranged so that each slot hole of an adjacent row of slot holes is vertically shifted, and an electron beam from an electron gun is placed in an effective screen area of the shadow mask. In the color cathode ray tube that irradiates the fluorescent film on the inner surface of the face panel through the positioned slot hole, the shadow mask is in contact with the upper and lower boundary lines of the effective screen area, and the vertical length is a slot hole having a predetermined value or less. It is characterized in that a slot elongated hole that connects both slot holes is provided without forming a bridge formed between the slot holes located inside thereof.

In the present invention, the opening width of the slot long hole is made smaller than the other slot holes over the entire length in the vertical direction, or the opening width of the slot long hole is smaller than that of the other slot holes. It is desirable that the taper shape is such that it gradually decreases toward the upper and lower boundaries of the effective screen area.

[0013]

In the shadow mask used in the color cathode ray tube according to the present invention, when the slot holes in contact with the upper and lower boundary lines of the effective screen area are less than half of the normal vertical length,
Since a slot long hole that connects the two slot holes is formed without forming a bridge between the slot hole and the slot hole located inside the slot hole, during exposure using this shadow mask, the effective screen area Since there is no shortage of the amount of exposure light at the portion in contact with the upper and lower boundary lines, no unevenness appears at the upper and lower boundary portions of the effective screen of the face panel.

[0014]

FIG. 1 shows an embodiment of a color cathode ray tube according to the present invention.
6 to 6 will be described. The following example is shown in FIG.
When applied to the shadow mask 8 used for the color cathode ray tube, the same parts as those in FIG.

Also in the shadow mask 8 used in the color cathode ray tube of the present invention, the slot hole group M has the slot holes 7 of the adjacent slot hole rows L commingled with each other in order to suppress the occurrence of the moire phenomenon as much as possible. The stripe pitch P _V
The slot holes 7 are arranged so as to be displaced in the vertical direction by a ratio based on, or the slot holes 7 are arranged randomly based on a random number.

In the present invention, as shown in FIG. 1, in the slot hole group M of the shadow mask 8, the slot hole 7 in contact with the upper and lower boundary lines c of the effective screen area b is, for example, a regular vertical length m. In the case of less than half of the above, the slot slot 7 is made to communicate with each other without forming the bridge 10 between the slot hole 7 and the slot hole 7 located inside thereof. Form. The formation of the slot long holes 7 ′ is performed simultaneously with the formation of the other slot holes 7 when the shadow mask 8 is manufactured. As described above, when the slot elongated hole 7 ′ is formed for the slot hole 7 having a length equal to or less than half the normal vertical length m, the longest slot elongated hole 7 ′ is m + m / 2 + n.

As described above, the predetermined slot hole 7 which is in contact with the upper and lower boundary lines c of the effective screen area b of the shadow mask 8 is communicated with the inner slot hole 7 to eliminate the bridge 10 as a slot long hole 7 '. When the fluorescent film 6 is formed on the inner surface of the face panel 3, when the exposure process is performed using the shadow mask 8, there is no shortage of the amount of exposure light at that portion. Therefore, the fluorescent film 6 thus formed.
When a color image is displayed on the face panel 3 by
As shown in FIG. 2, no unevenness appears at the upper and lower boundary portions d of the effective screen a of the face panel 3 (see FIG. 9).

Here, in the above embodiment, the case where the opening width of the slot long hole 7'is made the same as the opening width of the other slot holes 7 over the entire length m in the vertical direction has been described. The present invention is not limited to this, but can be configured as follows.

That is, since the slot elongated hole 7'is formed, the opening area of the slot elongated hole 7'becomes larger. Therefore, during the exposure process using the shadow mask 8, the exposure through the slot elongated hole 7'is performed. The amount of light may increase, and as a result, the end portion 6a 'of the striped phosphor 6'at a corresponding portion of the phosphor film 6 formed on the inner surface of the face panel 3 may become wider as shown in FIG. .

Therefore, in order to prevent this phenomenon,
As shown in FIG. 4, it is desirable that the opening width α of the slot long hole 7 ′ be slightly smaller than the opening width β [β> α] of the other slot holes 7. In this case, the opening width α of the slot long hole 7 ′ is 0.75 to the opening width β of the other slot holes 7.
About 0.98 is preferable. If it is smaller than 0.75, the amount of exposure light is too short to obtain a good striped phosphor 6 ', and if it is larger than 0.98, the end portion 6a' of the striped phosphor 6'is wide. The desired effect of preventing this cannot be obtained.

In this way, as shown in FIG. 5, the end portion 6a 'of the striped phosphor 6'in the corresponding portion of the phosphor film 6 formed on the inner surface of the face panel 3 does not become wide, and It becomes easy to form all the end portions 6a 'of the striped phosphor 6'in a uniform width.

In the above description, the case where the opening width α of the slot elongated hole 7'is made uniform over the entire length m in the vertical direction has been described. However, as shown in FIG. ″ May have a tapered shape so that its opening width gradually decreases toward the upper and lower boundary lines c of the effective screen area b (see FIG. 1).

[0023]

According to the present invention, when the slot hole in contact with the upper and lower boundary lines of the effective screen area of the shadow mask is less than half of the normal vertical length, the slot hole and the slot hole located inside thereof. Since a slot long hole that connects the two slot holes is formed without forming a bridge between the shadow mask and the shadow mask, the amount of exposure light at the portion in contact with the upper and lower borders of the effective screen area is increased during exposure using this shadow mask. Since there is no shortage, unevenness does not appear at the upper and lower boundaries of the effective screen of the face panel, an image with a good contour can be obtained, and a high-quality color cathode ray tube can be provided.

[Brief description of drawings]

FIG. 1 is a front view for explaining an embodiment of the present invention, showing a shadow mask used for a color cathode ray tube including an enlarged main part thereof.

FIG. 2 is a front view showing an effective screen of a face panel of a color cathode ray tube according to the present invention.

FIG. 3 is a partially enlarged front view showing an end portion of a striped phosphor in a phosphor film on an inner surface of a face panel.

FIG. 4 is for explaining another embodiment of the present invention,
Partially enlarged front view of a shadow mask having slotted holes with a small opening width

5 is a partially enlarged front view showing an end portion of a striped phosphor in a phosphor film on an inner surface of a face panel in the case of the embodiment of FIG.

6 is an enlarged front view of a main part of a shadow mask having a slotted hole having a tapered shape for explaining a modification of the embodiment of FIG.

FIG. 7 is a cross-sectional view showing a specific configuration example of a color cathode ray tube.

FIG. 8 is a front view including a partial enlargement showing a shadow mask of a conventional color cathode ray tube.

FIG. 9 is a front view showing an effective screen of a face panel of a conventional color cathode ray tube.

[Explanation of symbols]

 3 Face panel 5 Electron gun 6 Fluorescent film 7 Slot hole 7'Slot long hole 8 Shadow mask 10 Bridge L Slot hole row M Slot hole group b Effective screen area c Vertical border line m Vertical length

Claims (3)

[Claims] 1. A slot hole row having a plurality of vertically elongated slot holes having a predetermined vertical length arranged in the vertical direction is arranged in the horizontal direction, and each slot hole of an adjacent slot hole row is shifted in the vertical direction. A color cathode ray tube having a shadow mask having a group of slot holes arranged in the above, and irradiating an electron beam from an electron gun onto a fluorescent film on the inner surface of the face panel through the slot holes located in the effective screen area of the shadow mask. In the shadow mask, the shadow mask is in contact with the upper and lower boundaries of the effective screen area, and without forming a bridge formed between the slot hole having a vertical length of a predetermined value or less and the slot hole located inside thereof. A color cathode ray tube, characterized in that a slot elongated hole is provided which connects the two slot holes. 2. The color cathode ray tube according to claim 1, wherein the opening width of the slot elongated hole is made smaller than the opening widths of the other slot holes over the entire length in the vertical direction. 3. The color cathode ray tube according to claim 1, wherein the slot slot has a tapered shape such that the opening width thereof gradually decreases toward the upper and lower boundaries of the effective screen area.