JPH0572052B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method for manufacturing a cathode ray tube having a phosphor surface consisting of phosphor stripes in three colors of red, green, and blue. The present invention relates to a method of manufacturing a so-called high-definition color cathode ray tube with extremely small pitch.

[Background technology and its problems]

Conventionally, in order to manufacture color cathode ray tubes using the so-called black matrix method, in which the gaps between each phosphor were filled with a black substance in order to obtain sufficient contrast, carbon stripes were formed in advance on the front panel of the cathode ray tube using carbon, which is a black substance. After creating the carbon stripes, a phosphor slurry in which green, blue, and red phosphors are dispersed in a photosensitive resin is sequentially poured in, and pattern exposure is performed to create phosphor stripes between the carbon stripes. Are known. During the pattern exposure, a shadow mask, which is a color selection mechanism that serves to ensure that the three electron beams irradiated from an electron gun hit only the phosphor of the corresponding color, is used as a light shielding plate, and the light source is Generally, the phosphor slurry of each color is sequentially exposed by moving the electron beam to the center of deflection of each electron beam.

By the way, when a shadow mask is used as a light-shielding plate as described above, the shadow mask is removed from the front panel after each phosphor slurry is exposed, and the exposed phosphor slurry is developed and the next color of fluorescein is applied. The operation of pouring the body slurry, attaching the shadow mask again, and performing exposure must be repeated. Since the shadow mask has a structure such that it is held by a spring on the front panel, there is a risk that the shadow mask may be slightly misaligned when it is attached or removed.

Alternatively, because the temperature conditions are different between the carbon stripe creation and the phosphor stripe creation, there is a risk that the position of the shadow mask will deviate from the carbon stripe pattern when the phosphor stripe is created.

If the shadow mask is misaligned in this manner, the carbon stripes and the phosphor stripes do not match in position, and the quality of the color cathode ray tube is significantly degraded, such as by the inability to maintain white balance. In particular, the pitch of each phosphor stripe is 0.2
In so-called high-definition color cathode ray tubes, which are extremely small at ~0.3 mm, the above-mentioned drawbacks have become even more noticeable.

[Purpose of the invention]

SUMMARY OF THE INVENTION The present invention was proposed in order to eliminate the drawbacks of the above-mentioned conventional methods. The purpose is to provide a manufacturing method.

[Summary of the invention]

That is, in order to achieve the above-mentioned object, the present invention sequentially applies a phosphor slurry in which red, green, and blue phosphors are dispersed in a photosensitive resin to the inner surface of the front panel of a cathode ray tube on which carbon stripes are formed. When forming a phosphor screen by pattern exposure using a shadow mask as a light-shielding plate, a filter is placed between the shadow mask and the light source used for the pattern exposure to filter out the light from the light source in the wavelength range to which the photosensitive resin is sensitive. After blocking the light with this filter and arranging a light receiving element at at least one location on the outer surface of the front panel, and setting the position of the light source so that the amount of light incident on the light receiving element is maximized, The method is characterized in that the filter is removed, and the phosphor slurry is exposed in a pattern using the light source and shadow mask, and then developed.

〔Example〕

Hereinafter, a method for manufacturing a single electron gun three-beam type cathode ray tube to which the present invention is applied will be explained in accordance with the process order with reference to the drawings.

In the present invention, first, a front panel 1 molded from a transparent material such as glass is prepared, and the inner surface of the front panel 1, that is, the front panel 1 is sealed with a funnel section and a neck section, which will be described later, to form a cathode ray tube. When the cathode ray tube is assembled, black matrix carbon is pattern-exposed in advance using a slit-shaped shadow mask 3 on the inward facing surface of the cathode ray tube to create vertical stripes 2 as shown in FIG. put.

Next, as shown in FIG.
A green phosphor slurry 4 in which a phosphor that emits green light when irradiated with an electron beam is dispersed in an ultraviolet curable resin is poured over the entire inner surface of the front panel 1, and the front panel 1 has a slit shape having a narrow vertical gap 3a. Attach Shadow Mask 3.

The ultraviolet curable resin is preferably one that is cured by exposure to ultraviolet light and can be easily developed with water, and polyvinyl alcohol sensitized with ammonium dichromate is usually used.

As shown in FIG. 3, a light source 5 is placed above the shadow mask 3, and a light receiving element 6 is placed on the outer surface of the front panel 1, facing the light source 5. Further, between the shadow mask 3 and the light source 5, a gelatin filter 7 (for example, a Wratten filter manufactured by Eastman Kodak Co., Ltd.) for blocking ultraviolet rays is arranged.

As the light source 5, a forced air-cooled ultra-high pressure mercury lamp (approximately 1 KW) or the like is used.

The gelatin filter 7 may be of any type as long as it absorbs light in the wavelength range to which the ultraviolet curable resin contained in the green phosphor slurry 4 is sensitive.
Use something that can block light of 440 nm or less.

The light-receiving element 6 may be any element as long as it is sensitive to the light transmitted through the gelatin filter 7 out of the light from the light source 5, in this case light in the visible light range, and can indicate the amount of light. . The light receiving elements 6 are preferably provided at at least three locations near the center and near both ends of the front panel 1.

The light source 5, the gelatin filter 7, the shadow mask 3, the front panel 1, and the light receiving element 6 are arranged in this way, the light source 5 is turned on, and the light source 5 is turned on so that the light from the light source 5 becomes maximum at the light receiving element 6. Move 5 to set the position.

That is, as shown in FIG. 11A, if the light source 5 is accurately aligned, the light a passing through the gap 3a of the shadow mask 3 will match the gap between the carbon stripes 2, and most of the light will be lost. When the light a reaches the light receiving element 6, the amount of light received becomes maximum.

On the other hand, as shown in FIG. 11B, if the position of the light source 5 is shifted, a portion of the light a passing through the gap in the shadow mask 3 is blocked by the carbon stripe 2, and the light receiving element 6 The amount of light that reaches the area decreases, and the amount of light received decreases.

Therefore, by setting the light source 5 at a position where the amount of light incident on the light receiving element 6 is maximum, the green phosphor slurry 4 can be exposed with high precision at a predetermined position between the carbon stripes 2. It turns out.

Note that when setting the position of the light source 5 described above, the light source 5
Since the gelatin filter 7 blocks the ultraviolet light of the light emitted from the green phosphor slurry 4, the green phosphor slurry 4 will not harden.

Next, the gelatin filter 7 is removed and the green phosphor slurry 4 is subjected to pattern exposure, and after the shadow mask 3 is removed, it is developed using water to form a vertically striped green color as shown in FIG. A phosphor stripe 8 is created.

Next, as shown in FIG.
A blue phosphor slurry 9 in which a phosphor that emits blue light when irradiated with an electron beam is dispersed in an ultraviolet curable resin is poured into the inner surface, and the shadow mask 3 and A gelatin filter 7 is provided and the light source 5 is positioned so that the amount of light received by the light receiving element 6 is maximized as shown in FIG. 6.The gelatin filter 7 is removed and exposed.
Development is performed to create blue phosphor stripes 10 as shown in FIG.

Furthermore, similarly, a red phosphor slurry 11 in which a phosphor that emits red light when irradiated with an electron beam is dispersed in an ultraviolet curable resin is poured as shown in FIG. After setting the position, exposure and development are performed to create a red phosphor stripe 12 as shown in FIG.

In this way, a green phosphor stripe 8, a blue phosphor stripe 10, a red phosphor stripe 12
For the front panel 1, which has a fluorescent surface made of
After passing through the interlayer coating process, metal backing process, etc.
A funnel portion (not shown) is sealed, and a neck portion provided with an electron gun is attached to complete a color cathode ray tube.

As described above, in the above embodiment, since the position of the light source 5 is set while checking the amount of light incident on the light receiving element 6, each phosphor slurry 4,
It is now possible to perform highly accurate pattern exposure on carbon stripes 9 and 11, improving the positional accuracy of the carbon stripes 2 and each phosphor stripe 8, 10, and 12 formed between these carbon stripes 2, and improving quality. It has become possible to obtain cathode ray tubes with high performance. In particular, each of the phosphor stripes 8, 10,
Even in a high-definition color cathode ray tube with a small pitch as shown in FIG.

Furthermore, in the above-mentioned embodiments, the manufacturing yield when forming the fluorescent surface is improved, and the exposure table used during exposure does not require mechanical precision, making management easier.

By the way, the present invention is applicable not only to the single electron gun three-beam color cathode ray tube to which the above-mentioned slit-shaped shadow mask is attached, but also to the production of shadow-mask-type color cathode-ray tubes to which a dot-shaped or slot-shaped shadow mask is attached. It can be applied to

Furthermore, the photosensitive resin used in each of the phosphor slurries 4, 9, and 11 does not need to be an ultraviolet curable resin; in this case, a filter is used to block light in the wavelength range to which the photosensitive resin is sensitive; When the above-mentioned sensitive wavelength range is light other than the above-mentioned light-sensitive wavelength range, for example, when the above-mentioned light-sensitive wavelength range is visible light, a light-receiving element b sensitive to infrared light may be used.

Furthermore, if necessary, the light source 5 and the shadow mask 3 may be used during pattern exposure to correct errors caused by a difference in refractive index in the lens system based on the difference in wavelength between the light used for the pattern exposure and the light incident on the light receiving element 6. A correction lens may be provided between them.

Furthermore, a shielding plate provided with an aperture window having an appropriate width, for example, about 5 cm, is placed on the shadow mask 3, and the optimum position of the light source 5 in the portion facing into the aperture window is set by the light receiving element 6. Then, by moving these shielding plates and the light-receiving element 6 to determine the optimum position of the light source 5 at that location, sequential pattern exposure is performed to further form the phosphor stripes 8, 10,
It is also possible to improve the positional accuracy of 12.

〔Effect of the invention〕

As is clear from the description of the above embodiments, in the present invention, pattern exposure is performed on the phosphor slurry while confirming the position of the light source using a light receiving element, so that the carbon stripe and the phosphor stripe are It has become possible to manufacture high quality cathode ray tubes by matching the positions with high precision.

[Brief explanation of drawings]

1 to 10 are schematic cross-sectional views of main parts showing a method for manufacturing a cathode ray tube to which the present invention is applied according to the process order, and FIG. 1 is a carbon stripe creation process, and FIG. 2 is a green fluorescent Figure 3 shows the light source position setting process, Figure 4 shows the green phosphor stripe creation process, Figure 5 shows the blue phosphor slurry pouring process, Figure 6 shows the light source position setting process,
FIG. 7 shows a blue phosphor stripe forming step, FIG. 8 shows a red phosphor slurry pouring step, FIG. 9 shows a light source position setting step, and FIG. 10 shows a red phosphor stripe forming step. Figure 11A and 1
FIG. 1B is an enlarged cross-sectional view of a main part for explaining the light source position setting method, and FIG. 11A shows a state in which the light source is correctly placed, and FIG. 11B shows a state in which the light source is misaligned. 1... Front panel, 4, 9, 11... Fluorescent slurry, 5... Light source, 6... Light receiving element, 7... Gelatin filter.

Claims (1)

[Claims] 1. A phosphor slurry in which red, green, and blue phosphors are dispersed in a photosensitive resin is sequentially applied to the inner surface of the front panel of a cathode ray tube on which carbon stripes are formed, and a pattern is formed using a shadow mask as a light shielding plate. When exposing to light to form a phosphor screen, a filter is placed between the shadow mask and the light source used for pattern exposure, and out of the light from the light source, the light in the wavelength range to which the photosensitive resin is sensitive is blocked by the filter. After arranging a light receiving element at at least one location on the outer surface of the front panel and setting the position of the light source so that the amount of light incident on the light receiving element is maximized, the filter is removed and the phosphor slurry is applied. A method for manufacturing a cathode ray tube, comprising pattern exposure using the light source and a shadow mask, and development.