JPH113659A - Manufacture of fluorescent surface for cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a phosphor layer at an ultra-narrow pitch and a black color absorbing layer by repeating each process of coating, exposure and development of photosensitive film per each color at a position to be formed with each color phosphor stripe layer so as to form a photoresist layer. SOLUTION: An inner surface of a panel 11 is coated with a photosensitive film 12 of water soluble ultraviolet hardening resin, and after drying it, a color selecting mechanism 13 is used as an optical mask, and a light source is provided at a position for exposure of a first color, for example green color (G), and the photosensitive film 12 is exposed. A non-hardening resin is eliminated for development by washing with pure water, and a stripe photoresist layer 14 is formed at a position to be formed with a green phosphor stripe layer. In the case of a second color and other following color, a stripe photoresist layer 14 is formed at a position to be formed with each color stripe layer in the similar order. With this structure, slit width of the color selecting mechanism 13 is restricted at minimum, and a carbon-stripe layer at an ultra-narrow pitch is thereby formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a phosphor screen of a cathode ray tube such as a color television receiver, and more particularly to a method for producing a phosphor screen having an ultra-fine pitch.

[0002]

2. Description of the Related Art The fluorescent screen of a color cathode ray tube improves the contrast of a screen by arranging a light-absorbing layer of a black substance or the like in a gap between red, green and blue phosphors.
For example, a color phosphor screen having a stripe type light absorbing layer is manufactured as follows.

First, as shown in FIG. 7A, a photosensitive film 12 made of a water-soluble ultraviolet curable resin such as PVA (polyvinyl alcohol) is applied to the inner surface of a panel 11 of a cathode ray tube. After drying, as shown in FIG. 7B, the photosensitive film 12 is exposed to ultraviolet light through a color selection mechanism 13. As the color selection mechanism 13 of this example, a large number of narrow strip-shaped grid elements 8 are arranged at a predetermined pitch in the horizontal direction of the screen, and a slit-shaped electron element that is long in the vertical direction of the screen between adjacent grid elements 8. A color selection mechanism called a so-called aperture grill, which is formed by stretching a color selection electrode thin plate having a beam transmission hole (hereinafter referred to as a slit) 9 formed between opposing support members of a frame. Used.

As shown in FIG. 6, an exposure method is such that an ultra-high pressure mercury lamp 40 is installed at a position for the first color, for example, green (G) exposure, and a color selection mechanism 13 is provided via a correction lens 41.
Is used as an optical mask to expose the photosensitive film 12 to ultraviolet light. Then, the second color, for example, the position at the time of blue (B) exposure, and the third color
The ultra-high pressure mercury lamp 40 is moved to a position at the time of exposing a color, for example, red (R), and a position corresponding to each color is similarly exposed. That is, after exposure three times, as shown in FIG. 7C, the uncured resin is removed by washing with pure water or the like, and development is performed to form a striped photoresist layer 14 at a position corresponding to each color.

Next, as shown in FIG. 7D, a carbon slurry is applied to the entire upper surface including the photoresist layer 14 and dried to form a carbon film 15. Next, as shown in FIG. 8E, a reversing agent 16 is applied on the carbon film 15, and the photoresist layer 14 is decomposed by the reversing agent 16 that has permeated the carbon film 15, as shown in FIG. 8F.

Further, development with pure water, so-called reversal development (that is, the carbon layer laminated thereon together with the photoresist layer 14 is also stripped) is performed, and as shown in FIG. An absorption layer is formed.

Next, the first color, for example, a green phosphor slurry is applied, dried, exposed to ultraviolet rays in the same manner as the above-described exposure method, and then developed to form a predetermined black stripe as shown in FIG. 8H. Green phosphor stripe 1 between light absorbing layers
8G is formed. Similarly, the second color, for example, the red phosphor stripe 18R and the third color blue phosphor stripe 1 are interposed between the other black stripe light absorbing layers.
8B are respectively formed. Thereafter, an intermediate film is applied and formed on the upper surfaces of these phosphor layers, and after a metal back layer of aluminum is formed, firing is performed to form a target color phosphor screen 19.

[0008]

SUMMARY OF THE INVENTION Each of these phosphor layers 1
The narrower the width of the light absorbing layer 8 and the black stripe light absorbing layer 17, the finer the image of the cathode ray tube and the higher the resolution. The width t of the black stripe light absorbing layer 17 is determined by the pitch p of the slits 9 of the color selection mechanism 13 as a result. Generally, the width (W) of the slit 9 = [pitch (p) of the color selection mechanism]
× [ultraviolet transmittance of the electrode plate for color selection], and the ultraviolet transmittance is almost constant (0.2 to 0.1).
22), the pitch p and the slit width W are in a proportional relationship. That is, to reduce the pitch p,
The width W of the slit 9 is reduced.

A mercury lamp 40 used for exposing the photosensitive film 12
The ultraviolet rays emitted from the slits 9 undergo a diffraction effect called Fresnel diffraction when passing through the slit 9 of the color selection mechanism 13. For this reason, the light intensity distribution in each slit 9 generated on the photosensitive film 12 does not have a square wave shape but has various shapes called a so-called Fresnel distribution.

For example, as shown in FIG. 9, the Fresnel index (F), which is a factor that determines the approximate Fresnel distribution, is GH, the distance between the color selection mechanism 13 and the inner surface of the panel 11 (so-called grill height), and W, the slit width. , UV wavelength λ
Then, it is represented by the following equation (1).

[0011]

(Equation 1)

When the Fresnel index (F) is 2.0 or less, the Fresnel distribution can be approximated by a Gaussian distribution. For example, as the slit width becomes smaller, the F value becomes smaller. FIG. 10 shows the shape of the Gaussian distribution due to the difference in the Fresnel index (F). According to FIG. 10, when the width W of the slit 9 decreases, that is, when the F-number decreases, the light intensity distribution has a shape with a wide base.

To further simplify the description, the shapes of these Gaussian distributions are approximated by triangles. FIG. 11 is a graph in which the amount of energy of each of the ultraviolet rays R, G, and B from the positions of the three light sources of red, green, and blue received by the photosensitive film 12 is approximated by a triangle. That is, the vertices of the triangle indicate that the exposure energy of each ultraviolet ray is the highest, and the base of the triangle indicates that the exposure energy is 0.

FIGS. 11a, 11b, 11c and 11d
The slit width becomes smaller in the order of. FIG. 11A shows a state in which the slit width W is sufficiently large and the ultraviolet rays R, G, and B do not overlap, and FIG. 11B shows a state in which the entire surface of the photosensitive film 12 is exposed without the ultraviolet rays overlapping. FIG. 3C shows a state in which adjacent exposure portions overlap, and FIG. 4D shows a state in which two exposures overlap on the entire surface of the photosensitive film 12.

The photosensitive film 12 is made of a photosensitive agent such as PVA, and the degree of polymerization is determined by the amount of light absorbed. When the degree of polymerization of the photosensitive film 12 is high, the photosensitive film 12 does not fall off when washed with water, and when the degree of polymerization is low, the photosensitive film 12 easily falls off by washing with water.

Therefore, when developing after exposing three ultraviolet rays R, G and B as in the conventional exposure method,
As shown by the dotted lines in FIGS. 11C and 11D, since the light energy amounts of the two ultraviolet rays are added, the phosphor stripe layer 18 is added.
The ratio of the degree of polymerization of the photosensitive film 12 between the portion where the black stripe light absorbing layer 17 is formed and the portion where the black stripe light absorbing layer 17 is formed, that is, the intensity ratio of the photosensitive film 12 with respect to water washing decreases, and the portion where the phosphor stripe layer 18 is formed is It is difficult to remove the portion where the black stripe light absorbing layer 17 is formed by washing with water.

Since the ratio of the degree of polymerization of the photosensitive film is considered to be proportional to the ratio of the amount of light energy of ultraviolet light of each color, FIG.
The maximum value of the light energy of a is defined as the A value, and the energy amount at the bottom of the triangle is as shown by the triangle in FIGS. The portion overlapping with the triangle becomes the B value because the adjacent exposure amounts are added. Further, in FIG. 3D, when the overlap of adjacent triangles is added, the B value and the A value become the same.

Here, from the relationship between the A value and the B value, (A
−B) / A is considered to be a contrast ratio of the exposure amount. In FIGS. 11A and 11B, the contrast ratio is 1.0, in FIG. 11C, about 0.33, and in FIG. Can be considered. Usually, the exposed part of the photosensitive film is
All are not left and developed by a process such as washing with water, and a portion having a small exposure amount, that is, a portion that is not completely cured (uncured) is also removed. The adjustment of the remaining portion and the removed portion can be adjusted to some extent by a washing method, but it is difficult to adjust the difference in the degree of polymerization of the photosensitizers, that is, the contrast ratio of the exposure dose to some extent.

When the contrast ratio is 0.5 or less, it is said that it is difficult to form the photoresist layer 14 of FIG. 7 and therefore the carbon stripe layer 17.
If the contrast ratio is 0, it cannot be formed.
Therefore, if the width W of the slit 9 is reduced by the conventional method, the adjacent ultraviolet rays are overlap-exposed, and the contrast ratio of the exposure amount becomes small, so that the development becomes difficult. Therefore, the width W of the slit 9 cannot be reduced. It is not possible, and it is difficult to produce an ultra-fine pitch phosphor screen.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a method for producing a phosphor screen for forming a phosphor layer having a fine pitch and a black light absorbing layer.

[0021]

According to the present invention, a photosensitive material is applied, exposed, and developed for each color, and then the entire surface of the panel is processed.
A light absorbing material is applied and reversal development is performed to form a light absorbing layer on the phosphor screen. According to this method of forming a phosphor screen, it is possible to form a phosphor layer and a black light absorption layer having a very fine pitch.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The method for producing a phosphor screen of a cathode ray tube according to the present invention comprises the steps of: forming a light absorbing layer on the phosphor screen of the cathode ray tube; A light absorbing material is applied to the entire surface and reversal development is performed.

Hereinafter, description will be made with reference to the drawings. FIGS. 1 to 5 show a case where the present invention is applied to the production of a color phosphor screen in which a light absorbing layer has a stripe type in a color cathode ray tube.

FIG. 1 is a block diagram of a method for producing a fluorescent screen of a cathode ray tube according to the present invention. 2 to 5 are process charts for producing a phosphor screen of a cathode ray tube according to the present invention. FIG. 2A (FIG. 1)
As shown in step 21 of FIG.
On the inner surface, a photosensitive film 12 made of a water-soluble ultraviolet curable resin such as PVA (polyvinyl alcohol) is applied. After drying,
As shown in FIG. 2B (see Steps 22 and 23 in FIG. 1), similarly to the above, the color selection mechanism 13 is used as an optical mask, and the light source, for example, the mercury lamp 40 is used as the first color, for example, green (G). The photosensitive film 12 is exposed at the position at the time of exposure.

Next, as shown in FIG. 2C (see step 24 in FIG. 1), the uncured resin is removed by washing with pure water or the like and developed, for example, at a position where a green phosphor stripe layer is to be formed. Then, a striped photoresist layer 14 is formed.

Next, as shown in FIG. 3D (see step 25 in FIG. 1), the photosensitive film 12 is applied to the inner surface of the panel 11 again. After drying, FIG. 3E (see steps 26 and 27 in FIG. 1)
As shown in (2), the photosensitive film 12 is exposed by moving the light source to the position for the second color, for example, blue (B) exposure, using the color selection mechanism 13 as an optical mask.

Next, as shown in FIG. 3F (see step 28 in FIG. 1), the photoresist layer 14 is developed by washing with pure water or the like to form a stripe-shaped photoresist layer 14 at a position where a blue phosphor stripe layer is to be formed. To form

Next, as shown in FIG. 4G (see step 29 in FIG. 1), the photosensitive film 12 is applied to the inner surface of the panel 11 again. After drying, FIG. 4H (see steps 30 and 31 in FIG. 1)
As shown in (1), the color selecting mechanism 13 is used as an optical mask, and the light source is moved to a position for the third color, for example, red (R) exposure, to expose the photosensitive film 12.

Next, as shown in FIG. 4I (see step 32 in FIG. 1), the uncured resin is removed by washing with pure water or the like and developed, and, for example, a stripe shape is formed at a position where a red phosphor stripe layer is to be formed. Is formed.

In this manner, a stripe-shaped photoresist layer 14 is formed at the position where each color phosphor stripe layer is to be formed.
As shown in (1), a carbon slurry is applied to the entire upper surface including the photoresist layer 14 and dried to form a carbon film 15. Next, as shown in FIG. 5K (see step 34 in FIG. 1), a reversing agent 16 is applied on the carbon film 15,
The photoresist layer 14 is decomposed by the reversing agent 16 that has permeated the carbon film 15.

Next, development with pure water, so-called reversal development (that is, peeling of the carbon layer laminated thereon together with the photoresist layer) is performed, and a predetermined pattern is formed as shown in FIG. 5L (see step 35 in FIG. 1). A carbon stripe 17, that is, a black stripe light absorbing layer is formed.

After performing the above-described reversal development processing, FIG.
As shown in FIG. 7, a green phosphor slurry of the first color, for example, a green phosphor slurry is applied, dried, exposed to ultraviolet light through a color selection mechanism 13, developed, and processed to form a green phosphor stripe 18G between predetermined carbon stripes 17. 1 (see step 36 in FIG. 1), and similarly in the same manner, between each of the other carbon stripes 17, for example, a blue phosphor stripe 18B of the second color.
Then, a red phosphor stripe 18R of the third color is formed (see steps 37 and 38 in FIG. 1). Thereafter, an intermediate film is applied and formed on the upper surfaces of these phosphor layers, and after a metal back layer of aluminum is formed, firing is performed to form a target color phosphor screen 19.

In the present invention, when the photoresist layer 14 is formed at the position where the phosphor stripe layer of each color is to be formed, the application, exposure and development of the photosensitive film 12 are repeatedly performed for each color. Is formed, so that there is no overlap with exposure for other colors. Therefore, as described with reference to FIG. 11, since the exposure energy contrast ratio between the exposure center point and the end portion can be sufficiently provided, the width W of the slit 9 of the color selection mechanism 13 is minimized.
It is possible to form the carbon stripe layer 17 having a very fine pitch.

The width of the photoresist layer 14 depends on the width of the photosensitive film 12.
11 is controlled by controlling the water pressure of the developing water and the developing time during the development after the exposure of FIG.
The desired width can be controlled by controlling the maximum value A of the light energy indicated by.

For example, with a 14-inch color cathode ray tube,
When the pitch is 0.1 mm and the transmittance is 0.2, the width (W) of the slit 9 is 0.02 mm, the distance (GH) between the color selection mechanism 13 and the photosensitive film 12 is 1.5 mm, and the wavelength of the ultraviolet light. When (λ) is 0.365 μm, the Fresnel index (F) is 1.21. In this case, in the conventional method, the exposure energy contrast ratio becomes almost 0, and it is difficult to form the photoresist layer 14. However, according to the method of the present invention, the contrast ratio becomes 0.9,
Practically, the carbon stripe layer 17 is obtained.

According to the method of the present invention described above, the light energy contrast ratio between the portion corresponding to the center of each slit 9 and the portion corresponding to the end can be increased.
It is possible to form the black stripe light absorbing layer 17 and the phosphor stripe layer 18 having the extremely small width W of the slit 9, and therefore, it is possible to produce an extremely fine phosphor screen. That is, in a color cathode ray tube, it is possible to form a super-fine pitch color phosphor screen having a light absorbing layer for improving landing alliance.

The present invention can also be applied to the manufacture of a fluorescent screen of a cathode ray tube having other color selection mechanisms such as a slot type and a dot type in addition to the above examples.

[0038]

According to the method for producing a fluorescent screen of a cathode ray tube according to the present invention, the light energy contrast between the portion corresponding to the center portion and the portion corresponding to the end of each electron beam transmitting hole of the color selection mechanism at the time of exposure is reduced. Even when a color selection mechanism having an electron beam transmission hole for an ultrafine beam is used as an optical mask, washing and development can be performed, and an ultrafine light absorbing layer can be formed. Therefore, a high-definition color phosphor screen can be manufactured. Moreover, since the method of the present invention can use the conventional equipment and method as it is, no new equipment investment is required, and no new education and learning for work are required.

[Brief description of the drawings]

FIG. 1 is a block process diagram showing a method for producing a fluorescent screen of a cathode ray tube according to the present invention.

FIGS. 2A to 2C are process diagrams (part 1) illustrating an example of a phosphor screen manufacturing method according to the present invention.

3A to 3F are process diagrams (part 2) illustrating an example of a phosphor screen manufacturing method according to the present invention.

4A to 4G are process diagrams (part 3) illustrating an example of a phosphor screen manufacturing method according to the present invention.

FIG. 5 is a process diagram (part 4) showing an example of a phosphor screen manufacturing method according to the present invention.

FIG. 6 is an explanatory diagram of a method of exposing a photosensitive film.

7A to 7D are process diagrams (part 1) showing a conventional method for producing a fluorescent screen of a cathode ray tube.

8A to 8H are process diagrams (part 2) showing a conventional method for producing a fluorescent screen of a cathode ray tube.

FIG. 9 is an explanatory diagram of an optical path of ultraviolet light.

FIG. 10 is a correlation diagram between a Fresnel index and a waveform.

FIG. 11 is an explanatory diagram of ultraviolet irradiation energy.

[Explanation of symbols]

11 panel, 12 photosensitive film, 13 color selection mechanism, 14
Photoresist layer, 15 carbon film, 16 reversing agent,
17 carbon stripe, light absorbing layer, 18G green phosphor stripe, 18B blue phosphor stripe, 18
R red phosphor stripe, 19 phosphor screen, 40 mercury lamp 41 correction lens,

Claims (1)

[Claims] In a light absorbing layer forming step on a fluorescent screen of a cathode ray tube, a photosensitive material is applied, exposed and developed for each color, and then a light absorbing material is applied to the entire surface of the panel, and reversal development is performed. A method for producing a fluorescent screen of a cathode ray tube, the method comprising: