JP2003100232A - Color cathode-ray tube and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellent black matrix type color cathode-ray tube that is excellent in the uniformity of a screen, has the good texture of the screen, and can display high quality image, by reducing the unevenness on the fluorescent screen. SOLUTION: Exposing light passes through a plurality of electron beam through-holes 244, and allows an effect caused by the electron beam through- holes 244 having a shortcoming to be reduced, and an unevenness index showing nonuniformity on the fluorescent screen to decrease.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a color cathode ray tube, and more particularly to a black matrix film comprising a phosphor picture element and a non-emissive light absorbing material layer surrounding the phosphor picture element on the inner surface of the panel portion. The present invention relates to a black matrix type color cathode ray tube.

[0002]

2. Description of the Related Art A black matrix type color cathode ray tube is widely used as a video tube of a television receiver or a monitor tube of a personal computer or the like. FIG. 8 is a schematic cross-sectional view illustrating a structural example of a black matrix type color cathode ray tube. This color cathode ray tube includes a panel section 20 and a funnel section 2
1 and the neck portion 22 form a vacuum envelope, and an anode button 23 for introducing a high voltage is embedded in a part of the funnel portion 21. Reference numeral 24 is a shadow mask assembly, an example of which is shown in FIG. 9 described later in detail.

Further, reference numeral 25 is an electron gun, which is housed in the neck portion 22 and has the anode button 10.
The high voltage introduced from is applied via the internal conductive film. Reference numeral 26 is a deflection yoke, which is mounted on the transition region between the neck portion 22 and the funnel portion 21 of the vacuum envelope, and horizontally modulates the three modulated electron beams 27 emitted from the electron gun 25. By deflecting vertically (Y direction), the electron screen 27 two-dimensionally scans the fluorescent screen 28 to reproduce an image. The high voltage introduced from the anode button 10 is also applied to the conductive film formed on the phosphor screen 28. 29 is a magnetic shield.

A fluorescent screen 2 provided on the inner surface of the panel section 20.
As shown in FIG. 10, the details of an example of which is shown in FIG. 8, 8 is generally applied with phosphors of three colors of red (R), green (G), and blue (B) in a dot shape or a stripe shape. And a black matrix film that surrounds the phosphor pixel, and is arranged in close proximity to and facing the phosphor screen 28 to form a color selection electrode assembly (here, the shadow mask assembly 2
4. In the following description, the color selection electrode will be described as a shadow mask).

FIG. 9 shows an example of the shadow mask assembly shown in FIG. 8, showing the details of the shadow mask assembly in which the shadow mask, the mask frame and the spring are fixed, and FIG. 9 (a) is a side view. , (B) are plan views, and the same parts as those in the above-mentioned drawings are denoted by the same symbols. Figure 9
In (a) and (b), the shadow mask assembly 24 is composed of a shadow mask 241, a mask frame 242, and a spring 243. Shadow mask 241
11 has a main surface 241a having a large number of electron beam passage holes 244 whose shape is shown in FIG. 11, which will be described later, and a skirt portion bent at a right angle to the main surface 241a. . Then, the skirt portion is inserted inside the mask frame 242, and the skirt portion and the mask frame 242 are inserted.
And are welded and fixed at the positions indicated by x. The spring 243 is welded and fixed to each side of the mask frame 242, and constitutes a part of a mechanism for suspending the shadow mask assembly 24 in the panel portion.

The main surface 241a of the shadow mask is a portion that faces the fluorescent surface on the inner surface of the panel portion after shaping, and the perforated area in which a large number of electron beam passage holes 244 are formed and the periphery thereof are shown by a dotted line. It is composed of the outer peripheral portion of the non-perforated area. The main surface 241a is substantially rectangular and has different radii of curvature along the major axis, along the minor axis and along the diagonal. This is to achieve both the flatness of the screen as a color cathode ray tube and the maintenance of the mechanical strength of the shaped shadow mask.

Although aluminum killed steel is mainly used as a constituent material of the shadow mask 241, a shadow mask with a thin plate is used with the recent trend toward higher definition of color cathode ray tubes. In the color cathode ray tube using this thin shadow mask, a phenomenon called mask doming is likely to occur in which a part of the shadow mask is thermally deformed during operation and the electron beam spot is displaced from a predetermined position on the fluorescent screen. .

As a countermeasure, a mechanism for suspending the shadow mask assembly in the panel portion is improved and, in consideration of thermal expansion coefficient and physical hardness as the constituent materials, the difficulty of perforation is higher than that of the aluminum killed steel. Amber is also used regardless. In such a shadow mask, an original plate having a large number of electron beam passage holes at predetermined positions is punched into a predetermined shape by etching. After that, it is press-shaped and shaped into a shape having a substantially rectangular main surface having a substantially spherical shape and a skirt portion that is continuous with the main surface and is bent at about 90 degrees with respect to the main surface. The shaped shadow mask is fixed to the mask frame to form a mask assembly for use.

FIG. 10 is an enlarged schematic sectional view of a part of the main part of the color cathode ray tube shown in FIG. In FIG. 10, the fluorescent surface 28 provided on the inner surface of the panel unit 20 is 3
A three-color phosphor picture element 281 formed by applying color phosphors in a dot shape or a stripe shape, a black matrix film 282 surrounding the phosphor picture element 281, and a metal reflection film 2
As described above, the shadow mask assembly 24 having the light emitting element 83 is disposed in close proximity to the phosphor surface 28.

The three-color phosphor picture element 281 is dot-shaped,
It is composed of a red (R) color phosphor picture element 281R, a green (G) color phosphor picture element 281G and a blue (B) color phosphor picture element 281B. As is well known, the three-color phosphor picture element 281 has three light sources 30G and 30B indicated by imaginary lines after applying phosphor slurries of respective colors to the inner surface of the panel portion where the black matrix film 282 is formed. The corresponding specific electronic beam of the shadow mask 241 from the position of 30R respectively.
It is formed in the window portion of the black matrix film 282 through the step of performing the exposure shown by the arrow through the hole passing hole 244.

That is, for example, red phosphor picture element 281R
Is formed by being exposed only by the exposure light beam from the red exposure light source 30R through the corresponding one specific electron beam passage hole 244 of the shadow mask 241. Similarly, the blue and green phosphor picture elements are also exposed only by the light from the respective exposure light sources, in other words, the light rays emitted from one light source pass through one electron beam passage hole, One-to-one corresponding 1
This forms individual phosphor picture elements. Therefore, the original shape of the electron beam passage hole through which the light has passed appears in the phosphor picture element.

FIG. 11 shows an electronic beam of the shadow mask 241.
It is a cross-sectional schematic diagram of an example of the hole passing hole 244. In FIG. 11, the electron beam passage hole 244 has a shape in which a large hole and a small hole are combined at a boundary. A large hole (first hole portion) 244L faces the fluorescent screen 28 side and a small hole (second hole portion) 244S faces the electron gun 25 side with the boundary portion 244B as a boundary. Large hole (first hole) 244L
The bending direction of the small hole (second hole portion) 244S changes at the inflection point P0. That is, the shadow mask 2 shown in FIG.
The electron beam passage hole 244 of 41 is a large hole (first hole portion) 24.
4L and a small hole (second hole) 244S. This electron beam passage hole 244 is generally formed by etching a thin metal plate as described above. As mentioned above, the amber material is more difficult to perforate than aluminum killed steel. .

FIG. 12 is an explanatory view of a geometrical optical exposure profile for exposing and forming a phosphor screen, and the same parts as those in the above-mentioned drawings are denoted by the same symbols. In FIG. 12, an exposure dose profile 31 has a maximum area Dmax in the panel portion, the exposure intensity increases and the area decreases as the distance increases, and the minimum surface area Dmin at the top surface sets the specifications at a desired position 311. By doing so, it is used in a method of forming, for example, a phosphor picture element having a required area D. The phosphor screen of such a black matrix type color cathode ray tube is disclosed in, for example, Japanese Patent Publication No. 46-218.

[0014]

In the conventional black matrix type color cathode ray tube in which the black matrix film surrounds the phosphor picture elements as described above, bright and dark "rough irregularities" are generated on the phosphor screen and There is a problem that the uniformity of the image is deteriorated, the texture of the screen is impaired, and a high-quality image display cannot be obtained. Particularly, in the monitor tube, there is a problem that the screen becomes high definition and the brightness variation due to the unevenness easily causes eyestrain because the image is read from a close distance of, for example, about 50 cm. This will be described with reference to the drawings.

FIG. 13 is a front view of the panel portion 20, FIG. 13A is an overall view, and FIG. 13B is an enlarged plan view showing the portion A of FIG. The same reference numerals correspond to the same parts. In FIG. 13B, a plurality of phosphor picture elements 28 among the phosphor picture elements 281 forming the phosphor screen 28.
1B1, 281B2, 281B3, 281R3, 281
G4 has an illegal non-circular shape, and the red phosphor picture element 2
81R2 is a small-diameter picture element. These incorrect phosphor picture elements are formed from the exposure profiles shown in FIGS.

FIG. 14 is an explanatory view of a geometrical optical exposure profile of another example for exposing and forming a fluorescent screen. FIG. 14A is a normal profile, FIG. 14B is the normal profile, and FIG.
Is an incorrect profile. That is, FIG. 14 (A)
14B is the exposure profile of a normal phosphor picture element, whereas in FIG. 14B, the exposure profile lacks as shown by points c1 and d1. Blue phosphor picture element 281B2, 281B3
In addition, an irregularly shaped phosphor picture element such as a red phosphor picture element 281R3 is formed.

Further, in FIG. 14C, since the exposure profile is projected as shown by points c2 and d2, the blue phosphor picture element 281 is the phosphor picture element on the phosphor screen.
B1 and a green fluorescent substance picture element 281G4, such as a partially protruded fluorescent substance picture element, are formed. When such illegal phosphor picture elements are scattered between normal phosphor picture elements, unevenness of brightness and darkness occurs on the screen and the uniformity of the screen is deteriorated, and the texture of the screen is impaired. There was a problem that image display could not be obtained.

The causes of the unevenness of the phosphor screen are caused by the shadow mask, the black matrix film and the phosphor picture elements, which are related to the formation of the phosphor screen, and the metal reflection film. In particular, if there is a problem in the electron beam passage hole 244 of the shadow mask, the problem is entirely projected on the black matrix film and the phosphor picture element corresponding to the electron beam passage hole. This will be described with reference to FIG.

FIG. 15 is a schematic sectional view of another example of the electron beam passage hole of the shadow mask. In FIG. 15, a large number of electron beam passage holes 244 formed in the shadow mask 241 are large holes (first hole portions) 24 opened on the panel side.
4L and a small hole (second hole portion) 244 opened on the electron gun side
S, the large hole (first hole portion) 244L and the small hole (second hole portion)
It is composed of a boundary portion (third hole portion) 244B connecting the 244S.

The boundary between the first hole portion 244L and the third hole portion 244B is the first inflection point P1 from the first hole portion 244L to the third hole portion 244B, the second hole portion 244S and the third hole portion 244.
The boundary of B is defined by the second inflection point P2 extending from the second hole 244 to the third hole 244B. That is, FIG.
It can be rephrased that the electron beam passage hole 244 of the shadow mask shown in (4) is composed of the first hole portion, the second hole portion, and the third hole portion.

In the case of a shadow mask having such electron beam passage holes, the shadow mask 241 shown in FIG.
Third hole portion 24 which is a boundary portion of the electron beam passage hole 244 of
4B has a dimension T wider in the thickness direction as compared with the above-mentioned FIG. 11, so that irregularities occur in the black matrix film and the phosphor picture element due to irregular reflection of exposure light rays at the boundary portion. Further, the surface roughness of the inner surface of the electron beam passage hole 244 also causes a shape error.

Further, as a cause of unevenness, the problem of the film thickness of the black matrix film, the particle size of the phosphor itself, the filming composition, the film thickness of the metal reflection film, etc. are affected, and these various causes are combined. The unevenness of the fluorescent screen described above occurs,
A problem that high-quality image display cannot be obtained occurs, and a solution is required. The evaluation of such unevenness of the fluorescent screen has a problem that a person who makes a visual judgment has a large individual difference and it is difficult to obtain an accurate judgment. However, a technique for quantitatively measuring this is disclosed in JP-A-10-253497. It is disclosed in the publication.

FIG. 16 is a block diagram showing an embodiment of the known image quality measuring method and apparatus disclosed in the above publication. In FIG. 16, reference numeral 32 is a color cathode ray tube to be inspected, 33 is a camera, 34 is an image processing device, and 35 is a signal generator. Using these devices, the area of the fluorescent dots of the color cathode ray tube to be inspected, the amount of light emission per unit area of the fluorescent dots, the variation in the light emission distribution inside the fluorescent dots, the shape of the fluorescent dots, and other various physical properties of each pixel. The image quality is evaluated by extracting one or a plurality of characteristic features and calculating a quantification scale.

According to the image quality measuring method and apparatus described in this publication, the unevenness index representing the uniformity of the fluorescent screen is defined as one of the various physical characteristic values, for example, the area of the fluorescent dot, or A plurality of, for example, the fluorescent dot area and the amount of light emission per unit area of the fluorescent dot, each characteristic amount is extracted, and the numerical value obtained by subtracting the minimum value of the characteristic amount from the maximum value of the extracted characteristic amounts is the average value of the characteristic amounts. It is possible to obtain the value by dividing it by and expressing the obtained value as a percentage to quantify it.

That is, when this is expressed by an equation, the unevenness index (%) = {[(maximum value of feature amount) − (minimum value of feature amount)] / (average value of feature amount)} × 100. As described above, although the unevenness can be quantified, the problem associated with the unevenness has not been solved yet.

One of the objects of the present invention is to provide an excellent black matrix type color cathode ray tube in which unevenness is less likely to occur, the uniformity of the screen is excellent, the texture of the screen is good, and high-quality image display can be obtained. To do.

[0027]

In order to achieve the above-mentioned object, the present invention eliminates the cause of unevenness in each process by forming a fluorescent screen by superimposing a plurality of exposure rays having different exposure trajectories on each other. Reduced and improved the uniformity of the screen. The typical configuration of the present invention is as follows.

(1), a panel portion having a phosphor screen having a phosphor picture element and a black matrix film on the inner surface thereof, and a shadow mask arranged to face the phosphor screen and having a large number of electron beam passage holes; A collar having a vacuum envelope composed of a neck portion accommodating a gun and a funnel portion connecting the panel portion and the neck portion and having a deflection yoke on the outer periphery.
The cathode ray tube is characterized in that the phosphor screen has a phosphor image element having a small area in the peripheral portion as compared with the central portion, and the unevenness index representing the uniformity of the phosphor surface is 7% or less.

(2) In the above (1), the unevenness index is 4% or less.

(3) In the above (1) or (2),
The phosphor picture element has a dot shape.

(4) In any one of the above (1) to (3), in the shadow mask, the phosphor screen side is a large hole and the electron gun side is on a boundary of the electron beam passage hole. It is formed in a small hole and the thickness of the boundary is 6μ.
It is characterized by being m or less.

(5) In any one of the above (1) to (4), the size of a small area phosphor pixel in the peripheral portion of the phosphor screen is the size of the phosphor pixel in the central portion. 2/3 to 1 / 3n (n is an integer).

(6) In any one of the above (1) to (5), the unevenness index showing the uniformity of the black matrix film is 5% or less.

(7) In any one of the above (1) to (6), the unevenness index showing the uniformity of the shadow mask is 3% or less.

(8) In any one of the above (1) to (7), the unevenness index showing the uniformity of the black matrix film is smaller than the unevenness index showing the uniformity of the shadow mask.

(9) A panel section having a phosphor screen having a plurality of phosphor picture elements and a black matrix film on the inner surface thereof, and a shadow mask arranged to face the phosphor screen and having a large number of electron beam passage holes. , A neck portion accommodating the electron gun, a panel portion and a neck portion are connected to each other, and a deflection yaw is provided on the outer periphery.
A method of manufacturing a color cathode ray tube having a vacuum envelope configured with a funnel portion having a black matrix, wherein the black matrix film is formed by superposing a plurality of exposure light rays having different exposure trajectories. To do.

(10) In the above (9), the plurality of phosphor picture elements on the phosphor screen are formed by exposure by superimposing a plurality of exposure light rays having different exposure trajectories.

(11) In the above (9) or (10), the plurality of phosphor picture elements on the phosphor screen are formed by exposure by superimposing exposure light rays that have passed through different electron beam passage holes. Is characterized by.

(12) In any one of the above (9) to (11), the black matrix film is formed by exposing by exposing the exposure light beams passing through different electron beam passage holes. To do.

The present invention is not limited to the above-mentioned structure and the structure of the embodiment described later, and various modifications can be made without departing from the technical idea of the present invention.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to examples. FIG. 1 is a schematic cross-sectional view illustrating a structural example of an embodiment of the color cathode ray tube of the present invention. The color cathode ray tube shown in FIG. 1 has a panel portion 51 having a phosphor screen 50 having a black matrix film composed of a phosphor picture element and a non-emissive light absorbing material layer on the inner surface thereof, and a neck portion 52 accommodating an electron gun 61. , And the funnel portion 53 that connects the panel portion 51 and the neck portion 52 together form a vacuum envelope.

The phosphor screen 50 on the inner surface of the panel portion 51 is generally a phosphor picture formed by applying phosphors of three colors of red (R), green (G) and blue (B) in a dot shape or a stripe shape, respectively. The phosphor screen 50 has an element, a black matrix film that surrounds the phosphor picture element and is composed of a non-emissive light-absorbing substance layer such as carbon, and a metal reflective film that serves as a metal back layer. As will be described later, is provided with phosphor picture elements having different areas, and the unevenness index representing the uniformity of the phosphor screen is 7% or less. Further, a shadow mask 54 is arranged near the fluorescent screen 50. The shadow mask 54 is made of an amber material in consideration of the coefficient of thermal expansion and physical hardness.

The shadow mask 54 is a press-molded self-supporting shape-retaining type. The periphery of the shadow mask 54 is welded to the mask frame 57, and is suspended and supported by a stud pin 60 erected on the inner wall of the skirt portion of the panel portion 51 via a suspension spring 59. To be done. A magnetic shield 58 is fixed to the electron gun 61 side of the mask frame 57. A deflection yoke 55 is provided in the transition region between the neck portion 52 and the funnel portion 53 of the vacuum envelope.
The three modulated electron beams B emitted from the electron gun 61 are deflected horizontally (X direction) and vertically (Y direction) to scan the fluorescent screen 50 two-dimensionally with the electron beam B. Reproduce the image.

The internal conductive film 62 formed on the inner surface of the funnel portion 53 applies the high voltage introduced from the anode button to the electrode forming the main lens of the electron gun 61 and the metal reflection film of the fluorescent screen 50. To do. In addition, 65 shows the whole color cathode ray tube.

FIG. 2 is a plan view of the main part of the phosphor screen of the embodiment of the color cathode ray tube of the present invention shown in FIG. 1, which corresponds to the vicinity of the outermost periphery of the electron beam passage hole of the shadow mask. The same parts as those in the above-mentioned drawings are denoted by the same symbols. Figure 2
In each color phosphor picture element 281G, 281B and 28
1R has the same predetermined size as the conventional regular phosphor picture element, while each color phosphor picture element 281g, 281b and 2
81r is a small-area phosphor picture element, which is about 2 compared to the regular one.
The area is / 3. In addition, each color phosphor picture element 281g ',
Reference numerals 281b 'and 281r' are phosphor picture elements having a smaller area, which is about 1/3 the area of a regular picture element. Line L
Is a line connecting the outermost electron beam passage holes.

FIG. 3 is a plan view for explaining the method for exposing and forming the phosphor screen shown in FIG. 2, and the same parts as those in the above-mentioned drawings are denoted by the same symbols. In FIG. 3, the green phosphor picture elements 281G, 281g, and 281g 'are formed by exposing three light sources 30G1, 30G2, and 30G3 as exposure light sources.
Are arranged at an interval of 3S, which is three times the interval S of the exposure light sources of the three colors, and the regular green phosphor picture element 281G emits three light rays that have passed through three different electron beam passage holes 244. Overlapping exposure.

The small-area green phosphor picture element 281g is exposed by two light sources of the exposure light sources 30G1 and 30G3, and the area is ⅔ of 281G. Further, the small area green phosphor picture element 281g 'is exposed by one light source of the exposure light source 30G3, and the area is 1/3 of 281G. The same method as the phosphor picture element can be used for forming the black matrix film 282. Note that reference numerals 30B1, 30B2, 30B3 and 30R in FIG.
Reference numerals 1, 30R2, and 30R3 indicate respective exposure light source arrangements for other colors. In this example, the three light sources 30G1 and 3G3
Although 0G2 and 30G3 are arranged in parallel, the same effect can be obtained by moving one or a plurality of light sources.

FIG. 4 is a plan view showing another example of the arrangement of exposure light sources used in the method for manufacturing a color cathode ray tube of the present invention.
In this example, nine light sources 30G1 to 30G9 which are three times as large as those in FIG. 3 are used.
Is used. Therefore, the small-area green phosphor picture element 281g to be formed has various sizes of about 1/9 to 6/9 of the regular one, and the formation range is only in the long side direction of the phosphor screen in FIG. On the other hand, with these nine arrangements, the phosphor picture elements having a small area are formed in both the long and short sides of the phosphor screen.
Also in this example, the number of light sources can be reduced by moving the light sources.

FIG. 5 and FIG. 6 show the relationship between the characteristics of the shadow mask and the nonuniformity index representing the uniformity of the fluorescent screen, the black matrix film and the shadow mask when a plurality of exposure light sources are used to superimpose exposure rays having different trajectories. FIG. Figure 5
6 uses 9 light sources, and FIG. 6 uses 9 light sources. The thickness dimension T and unevenness of the boundary portion 244b of the electron beam passage hole 244 of the shadow mask 241 shown in FIG. It shows the relationship of the indexes. 5 and 6, the variation in the diameter of the electron beam passage hole 244 of the shadow mask used is within 2%.

First, FIG. 5 shows the fluorescent screen pitch: 0.26 m.
m, shadow mask material: amber material, shadow mask plate thickness: 0.13 mm, electron beam passage hole diameter: 115-1
An area was used as a physical feature amount in the method disclosed in Japanese Patent Laid-Open No. 10-253497 mentioned above using a color cathode ray tube having a 51 cm screen diagonal size with a specification of 20 μm. In FIG. 5, the thickness T of the boundary portion 244b of the specific electron beam passage hole is 7 μm.
Even if an illegal light profile is exceeded, the exposure light passing through the other electron beam passage hole cooperating with this particular electron beam passage hole will cover the desired shape to obtain a desired shape. The unevenness index, which indicates the uniformity of the surface, does not exceed 7%.

On the other hand, with the conventional single exposure orbit, 7 μ
When the thickness exceeds m, the unevenness index reaches 10%, and even when it exceeds 6 μm, the unevenness index exceeds 8%. When the unevenness index exceeds 8%, unevenness of brightness and darkness on the fluorescent screen remarkably occurs. The uniformity deteriorated, the quality of the screen was impaired, and high-quality image display could not be obtained. Therefore, the unevenness index representing the uniformity of the phosphor screen needs to be 7% or less, and preferably 4% or less, the existence of the unevenness can be ignored, and higher quality image display can be realized. To this end, the boundary 2
Although the thickness dimension T of 44b is preferably 6 μm or less, the tolerance of the thickness dimension T is widened by superimposing a plurality of exposure tracks.

Next, as shown in FIG. 6, using a shadow mask having the same specifications as in FIG. 5 and using nine exposure light sources, it was confirmed that the unevenness index can be further reduced as compared with FIG. 5 using three light sources. Has become. In particular, the unevenness index of the black matrix film is improved compared to the shadow mask alone, and the effect of the present invention due to the superposition of a plurality of exposure trajectories is remarkably exhibited. Further, the tolerance of the surface roughness of the electron beam passage hole 244 is higher than that of the conventional one. Here, the data of the BM (black matrix) film and the mask (shadow mask) in FIG. 5 and FIG. 6 were collected during the manufacturing process of the color cathode ray tube.

Although the surface of a shadow mask is usually blackened, the thickness of this blackened film is at least about 10% thicker than that of the standard specification, so that even if the surface roughness is the same, it is standard. The unevenness index can be improved compared to the specifications. That is, in the case of shadow masks having surface roughnesses of 0.12 μm and 0.30 μm, the unevenness index of the black matrix film using the standardized blackening film is 3.2%,
The value of 4.0% was improved to 3.1% and 3.6% by increasing the blackened film thickness by 10%, and the unevenness index of the phosphor screen was also improved accordingly.

Here, in the above embodiment, the characteristics of the shadow mask and the unevenness index were explained. However, as described above, the cause of the unevenness of the fluorescent screen is not only the shadow mask but also the black matrix film and the fluorescent substance picture. Since various elements such as the element and the metal reflection film are also related, the unevenness index can be further improved by improving the respective characteristics.
FIG. 7 is a plan view of an example of an exposure apparatus used in the method for manufacturing a color cathode ray tube according to the present invention, in which an apparatus main body 71 has three light sources 72.
1, 722 and 723 are arranged at intervals of 3S,
The device main body 71 is mounted on a light house for use.

[0055]

As described above, according to the present invention,
Even if there is a problem with a small number of electron beam passage holes by superimposing exposure light rays with different exposure trajectories on exposure, defects can be eliminated by a synergistic effect, and unevenness occurring on the fluorescent screen can be eliminated. The present invention has enabled an excellent black matrix type color cathode ray tube capable of producing a high-quality image display with excellent screen uniformity, excellent screen uniformity, and a manufacturing method thereof.

[0056]

[Brief description of drawings]

FIG. 1 is a schematic sectional view illustrating a structural example of an embodiment of a color cathode ray tube according to the present invention.

FIG. 2 is a plan view of a main part of a phosphor screen of the color cathode ray tube according to the present invention shown in FIG.

3 is a plan view for explaining the exposure forming method of the fluorescent screen shown in FIG. 2, showing the relationship between the surface roughness near the boundary of the electron beam passage hole of the shadow mask and the unevenness index of the fluorescent screen. FIG.

FIG. 4 is a plan view showing another example of the arrangement of exposure light sources used in the method for manufacturing a color cathode ray tube according to the present invention.

FIG. 5 is an explanatory diagram of the relationship between the thickness of the boundary portion of the electron beam passage hole of the shadow mask and the exponent index of the fluorescent screen when the exposure light rays having different trajectories are superimposed by using three exposure light sources.

FIG. 6 is an explanatory diagram of the relationship between the thickness of the boundary portion of the electron beam passage hole of the shadow mask and the unevenness index of the fluorescent screen when the exposure light beams having different trajectories are superposed using nine exposure light sources.

FIG. 7 is a plan view of an example of an exposure apparatus used in the method for manufacturing a color cathode ray tube according to the present invention.

FIG. 8 is a schematic cross-sectional view illustrating a structural example of a black matrix type color cathode ray tube.

9A and 9B show an example of the shadow mask assembly shown in FIG. 8, FIG. 9A being a side view and FIG. 9B being a plan view.

10 is a schematic cross-sectional view showing an enlarged part of a main part of the color cathode ray tube shown in FIG.

FIG. 11 is a schematic sectional view of an example of an electron beam passage hole of a shadow mask.

FIG. 12 is a geometrical optical exposure profile for explaining phosphor screen forming exposure.

FIG. 13 shows a front view of a panel portion of a color cathode ray tube,
(A) is a front view of the whole, (b) is a plan view showing an enlarged A portion of (a).

FIG. 14 is an explanatory diagram of another example of a geometrical optical exposure profile for exposure to form a fluorescent screen, where (a) is a normal profile and (b) and (c) are incorrect profiles.

FIG. 15 is a schematic cross-sectional view of another example of the electron beam passage hole of the shadow mask.

FIG. 16 is a configuration diagram showing an embodiment of an image quality measuring method and apparatus.

[Explanation of symbols]

20, 51 Panel portion 21, 53 Funnel portion 22, 52 Neck portion 24, 54 Shadow mask 25, 61 Electron gun 28, 50 Fluorescent screen 32 Color cathode ray tube 33 Camera 34 Image processing device 35 Signal generator 241 Shadow mask 244 electron Beam passing hole 244b Boundary 244L Large hole 244S Small hole 281G, B, R Phosphor picture element 282 Black matrix film 283 Metal reflection film 281 g, g ', b, b', r, r'Small area phosphor Picture element.

Claims (12)

[Claims] 1. An electron gun comprising: a panel section having a phosphor screen having a phosphor picture element and a black matrix film on an inner surface thereof; and a shadow mask arranged to face the phosphor screen and having a large number of electron beam passage holes. A color cathode ray tube having a vacuum envelope formed by a housed neck portion, a panel portion and a neck portion connected to each other, and a funnel portion having a deflection yoke on the outer circumference. Has a small area phosphor element in the peripheral area compared to the area, and the unevenness index that indicates the uniformity of the fluorescent surface is 7%
A color cathode ray tube characterized in that: 2. The color cathode ray tube according to claim 1, wherein the unevenness index is 4% or less. 3. The color cathode ray tube according to claim 1, wherein the phosphor picture element has a dot shape. 4. The shadow mask has a large hole on the phosphor screen side and a small hole on the electron gun side with the electron beam passage hole at a boundary, and the thickness of the boundary is formed. Is 6
The color cathode ray tube according to claim 1, wherein the color cathode ray tube has a thickness of less than or equal to μm. 5. The size of a small area phosphor picture element in the peripheral portion of the phosphor screen is 2/3 of the size of the phosphor picture element in the central portion.
The color cathode ray tube according to any one of claims 1 to 4, wherein the color cathode ray tube is 1 to 3 / 3n (n is an integer). 6. The color cathode ray tube according to claim 1, wherein the unevenness index showing the uniformity of the black matrix film is 5% or less. 7. The color cathode ray tube according to claim 1, wherein the unevenness index showing the uniformity of the shadow mask is 3% or less. 8. The color cathode ray tube according to claim 1, wherein the unevenness index showing the uniformity of the black matrix film is smaller than the unevenness index showing the uniformity of the shadow mask. 9. A panel section comprising: a phosphor screen having a plurality of phosphor picture elements and a black matrix film on an inner surface thereof; and a shadow mask arranged to face the phosphor screen and having a large number of electron beam passage holes. A method of manufacturing a color cathode ray tube having a vacuum envelope including a neck portion accommodating a gun, and a funnel portion connecting a panel portion and the neck portion with each other and having a deflection yoke on an outer periphery, The method for manufacturing a color cathode ray tube, wherein the black matrix film is formed by exposing a plurality of exposure light beams having different exposure trajectories in an overlapping manner. 10. The method of manufacturing a color cathode ray tube according to claim 9, wherein the plurality of phosphor picture elements on the phosphor screen are formed by exposure by superimposing a plurality of exposure light rays having different exposure trajectories. 11. The plurality of phosphor picture elements on the phosphor screen are formed by exposing the exposure light rays that have passed through the different electron beam passage holes by superimposing them. Manufacturing method of color cathode ray tube. 12. The color cathode ray tube according to claim 9, wherein the black matrix film is formed by exposing the exposure light beams passing through the different electron beam passage holes in an overlapping manner. Manufacturing method.