KR970008562B1 - Color cathode-ray tube - Google Patents

Abstract

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Description

Method and apparatus for forming fluorescent surface of colored cathode ray tube

1 is a longitudinal sectional view showing a typical cathode ray tube.

Figure 2 is a state diagram showing the temperature distribution acting on the shadow mask during operation of the cathode ray tube.

3 is a longitudinal sectional view showing a conventional shadow mask thermal deformation state.

4 is a longitudinal sectional view showing the present invention.

5 is a bottom view showing the installation state of a heating wire that is a heating part of the present invention.

* Explanation of symbols for main parts of the drawings

1: Front panel 7: Shadow mask

11: top plate 12: filter

13 correction lens 14 light source

15: heating part

The present invention relates to a method and apparatus for forming a fluorescent surface of a color cathode ray tube, and more specifically, to a shadow mask in a process of forming a black matrix and a fluorescent film so that a temperature of the same condition as that of the cathode ray tube is applied is applied to a shadow mask. It is to prevent the fall of color purity by.

A general color cathode ray tube is a vacuum container consisting of a rectangular front panel 1, a nutmeg funnel 2 and a neck 3, as shown in the attached first drawing. There is formed a phosphor screen 4 coated with red, green, and blue striped phosphor layers, and an inline electron gun 5 is provided in the neck 3 corresponding to the red, green, and blue phosphor layers. In the proximal position of the phosphor screen 4, a shadow mask 7 supported by the support frame 6 is provided by a bimetal spring 8, which is an elastic member.

Therefore, when the red, green, and blue electron beams are emitted from the electron gun 5 installed in the neck 3, the electron beam is deflected by the deflector 9 installed outside the funnel 2, and then the phosphor layer through the shadow mask 7 Landing on, a predetermined color image is reproduced on the phosphor screen 4. When the electron beam emitted from the electron gun 5 is affected by an external magnetic field such as a geomagnetic field, the electron beam is not landed correctly on the stripe phosphor layer, thereby degrading color purity of color image reproduction.

Accordingly, in order to eliminate the above phenomenon, the shield 10 of the ferromagnetic metal plate inside the funnel 2 is fixed to the sopot frame 6 to protect the electron beam from the geomagnetic field.

In this color cathode ray tube, the number of slit-shaped holes formed in the horizontal direction of the shadow mask 7 is 1/3 of the number of arrays of phosphors formed in the horizontal direction, and the effective electron beam passing through the slit-shaped holes is Less than one third of the emitted electron beam and the remaining electron beam collides with the shadow mask 7 to heat the shadow mask, so that the shadow mask is deformed when the cathode ray tube is operated.

Looking at the temperature distribution when the shadow mask is heated, it is heated to about 8 ℃ in the first region, the central region of 76 ℃, 72 ℃ in the third region, as shown in FIG.

Accordingly, as shown in FIG. 3, the shadow mask 7 is deformed to be out of the “q” which is a deformation allowance distance between the phosphor screen 4 and the shadow mask 7, and the electron beam x emitted from the electron gun 5 is emitted. Since the phosphor screen 4 is mislanded out of the predetermined phosphor layers 4a and 4b to 4a 'and 4b', the color purity is lowered.

In order to prevent such a drop in color purity, two methods have been proposed.

In the first method, the bimetal spring 8 supports the support frame 6 to the wall on the side of the front panel 1 so that the shadow mask 7 thermally expands due to the collision with the electron beam. In addition, it is a method of correcting the landing position of the electron beam that collides with the phosphor screen 4 while being thermally deformed to compensate for the entire position of the shadow mask.

The second method, which was previously filed in Patent Application No. 89-20120, solves this problem in the black matrix forming process and the fluorescent film forming process of the cathode ray tube.

In the black matrix forming process of the cathode ray tube, the drying process after the photosensitive agent injection and the doming correction process of shadow mask heating are added between the three-color exposure process, and the drying adjustment after the green, red, and blue phosphor injection is also performed during the fluorescent film formation process. The shadow mask heating method is added to prevent the shadow mask from being dope.

The shadow mask 7 predicts the mislanding points 4a 'and 4b' in advance when the shadow mask is normally transformed from the original position to the same position as the dashed line as the second degree when the cathode ray tube manufactured as described above is normally driven. Since it was prepared, it is possible to be landing at the phosphor point of 4a, 4b.

However, bimetal spring 8, the first of these methods, uses a bimetal spring to increase the number of parts resulting in an increase in the manufacturing process, resulting in reduced productivity as well as component coupling (between the support frame, bimetal spring and the front panel). It is difficult to raise the price and obtain the reliability due to the precision requirement, and in particular, the rapidity of compensating the dominant phenomenon due to the heat conduction path of the shadow mask, the support frame and the bimetal spring is poor.

In addition, since the second method performs the process under a single temperature condition during the black matrix forming process and the fluorescent film forming process, it is impossible to realize the temperature distribution during the actual operation such as the second degree, and thus mislanding the whole range of the phosphor screen. As a result, it is not possible to eliminate the local color purity, as well as the drying process after the photosensitive agent injection during the black matrix forming process, and the doming correction process for heating the shadow mask between the three color exposure processes. Since it is difficult to adjust the temperature change with movement or time delay, it becomes difficult to keep the temperature constant during operation.

The present invention has been made to solve such a problem in the prior art to prevent the occurrence of miss landing by manufacturing the shadow mask under the condition of the shadow mask is deformed during the manufacturing process of the shadow mask as the actual operation. The purpose is to make it possible.

Still another object of the present invention is to adjust the temperature at the time of heating the shadow mask by changing the resistance value of the central portion and the peripheral portion of the heating wire used as the heating portion.

According to an aspect of the present invention for achieving the above object, in the black matrix forming process and the fluorescent film forming process in the exposure, the shadow mask is applied to the product at the same temperature conditions as the temperature distribution that is heated in the outer area of the shadow mask Provided is a method of forming a fluorescent surface of a color cathode ray tube adapted to form a black matrix and a fluorescent film while the shadow mask is heated to a lower temperature toward the zone.

According to an aspect of the present invention for performing the above method, the filter and the saw are arranged to perform an exposure process by sequentially installing a filter, a correcting lens, and a light source under the top plate supporting the front panel on which the shadow mask is fixed. Provided is a fluorescent surface forming apparatus for a color cathode ray tube provided with a heating section for heating the temperature of the entire surface of the shadow mask to different temperatures between the plates.

Hereinafter, the present invention will be described in more detail with reference to FIGS. 4 and 5 of the accompanying drawings.

FIG. 4 is a longitudinal sectional view showing the present invention, and FIG. 5 is a bottom view showing the installation state of a heating wire which is a heating part of the present invention. In order to prevent the black matrix forming process and the fluorescent film forming process, the shadow mask 7 is heated at a lower temperature from the center area of the shadow mask to the outer area so as to be in the same condition as the temperature distribution heated when the product is applied to the product. In this state, a black matrix and a fluorescent film are formed.

That is, the process is performed in a state where the first region, which is the center of the shadow mask 7, is heated to a temperature of 78-82 ° C., the second area is 74-78 ° C., and the third area is 70-74 ° C. .

As a result, the heating temperature of the shadow mask can be easily adjusted to improve the reliability of the process, and the electron beam path during the operation of the cathode ray tube is matched with the light path during exposure and the operation of the electron beam path in the entire range of the phosphor screen 4. Landed correctly on the screen, high quality color purity is achieved.

Referring to the configuration of the fluorescent surface forming apparatus performing the process as described above is as follows.

In the device of the present invention, the filter 12 and the correction lens 13 are sequentially installed below the top plate 11 supporting the front panel 1 on which the shadow mask 7 is fixed, as in the fourth diagram. Under the lens, a light source 14 for irradiating light toward the front panel 1 is provided, and a heating unit for heating the shadow mask 7 to have different temperatures between the top plate 11 and the filter 12. (15) is provided.

The heating unit 15 is a hot wire, and as shown in FIG. 5, the center is narrowly spaced and wider toward the outer side of the cochlear form so that the temperature of the center portion of the shadow mask is higher than the temperature of the outer portion during the fluorescent surface forming process.

The hot wire is preferably a high melting hot wire such as nickel (Ni) in consideration of the service life and the like.

The heating temperature of the shadow mask is adjusted to the resistance value of the heating wire by varying the resistance values of the central portion and the peripheral portion of the heating wire as described above.

Therefore, when a predetermined voltage is applied to the heating wires of the heating unit 15 during the black matrix forming process and the fluorescent film forming process, the shadow mask 7 is applied to the actual product (cathode ray tube) and the shadow is the same as the temperature distribution. Since the temperature is distributed on the surface of the mask, the exposure is performed in this state.

That is, the shadow mask 7 is deformed by the heat generated by the operation of the hot wire, and the exposure operation is performed in a state in which the slit-shaped hole positions formed in the shadow mask are changed as shown in FIG.

The cathode ray tube manufactured as described above is applied to the product, and since the shadow mask is thermally deformed even though the shadow mask is thermally deformed by the electron beam, the electron beam is accurately landed on a predetermined phosphor because the shadow mask is thermally deformed. As well as obtaining the quality of the color purity, it is possible to heat the respective parts of the shadow mask to different temperatures without the addition of a process unlike the conventional, so that it is advantageous for temperature adjustment, thereby improving the workability.

Claims (5)

When the shadow mask is applied to the product during the black matrix forming process and the fluorescent film exposure, the black matrix and the matrix are heated at a lower temperature from the center to the outer area of the shadow mask so that the temperature is the same as the temperature distribution. A fluorescent surface forming method of a color cathode ray tube adapted to form a fluorescent film. In order to perform the exposure process by installing a filter, a correcting lens, and a light source in order under the top plate supporting the front panel to which the shadow mask is fixed, the temperature of the entire surface of the shadow mask is different between the filter and the top plate. A fluorescent surface forming apparatus of a color cathode ray tube, comprising a heating unit for heating to a temperature. 3. The fluorescent surface forming apparatus of a color cathode ray tube according to claim 2, wherein the heating portion is a hot wire, and a central portion thereof is narrowly spaced and wound around a cochlea in a wider direction. 4. The fluorescent surface forming apparatus of a color cathode ray tube according to claim 3, wherein the hot wire is a high melting hot wire. 5. The fluorescent surface forming apparatus of a color cathode ray tube according to claim 3 or 4, wherein the heating temperature of the shadow mask is adjusted to the resistance value of the heating wire by varying the resistance values of the central and peripheral portions of the heating wire.