KR20010077288A - Shadow mask in cathode ray tube - Google Patents

Abstract

PURPOSE: A shadow mask of a color cathode-ray tube is provided, which restricts doming effect due to thermal expansion according to electron beams irradiated on the shadow mask to improve color purity. CONSTITUTION: A color cathode-ray tube has a shadow mask on which an electron reflecting layer is formed. The electron reflecting layer is formed on the face of the shadow mask on which electron beams are irradiated. The electron reflecting layer contains a material for reducing doming. The material for reducing doming is configured of an electron reflecting material and heat reflecting material. The electron reflecting material contains at least one of tungsten and bismuth. The electron reflecting material is included in the material for reducing doming by 10-33wt%. The heat reflecting material is contained in the material for reducing doming by 47-7-wt%. The electron reflecting layer is formed through screen printing method.

Description

Shadow mask in cathode ray tube

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask for a color cathode ray tube, and more particularly, to a shadow mask for a color cathode ray tube capable of reducing a doming phenomenon in which the shadow mask swells due to the collision of electron beams emitted from the cathode.

1 is a schematic diagram of a typical color cathode ray tube, FIG. 2 is an enlarged view of a shadow mask and a panel portion of the color cathode ray tube, and FIG. 3 is a view showing a phosphor of the panel and an electron beam reaching the phosphor.

1 to 3, a cathode ray tube generally includes a stem pin 101 to which a voltage is applied, a cathode 102 for emitting electrons, and an electron emitted from the cathode to control / accelerate the lens. The first electrode 103, the second electrode 104, the third electrode 105, the fourth electrode 106, the fifth electrode 107, and the sixth electrode 108 for forming a phosphor to emit light A panel 114 to which 201 is applied, a funnel 109 connected to the panel 114 to maintain a vacuum therein, and an upper portion of the sixth electrode 108. A shielded cup 110 for fixing the electron gun to the neck portion of the funnel 109 while electrically connecting the electron gun and the funnel 109 to the neck, and an electron beam formed by the electrons emitted from the electron gun. a deflection yoke 111 for evenly deflecting the beam 112 to the entire panel 114 and a shadow for selecting colors by maintaining a predetermined distance from the panel 114 It consists of a shadow mask 113.

The operation of the cathode ray tube having the above configuration will be briefly described.

First, when a voltage is supplied to the stem pin 101, heat is applied to the cathode 102, and electrons are emitted from the cathode 102 to which the heat is applied. The emitted electrons are focused / accelerated by the first electrode 103 to the sixth electrode 108. The electron beam 112 formed by the focused / accelerated electrons is deflected by the deflection yoke 111 and irradiated evenly on the entire panel 114, and the electron beam 112 is a shadow mask provided in front of the panel 114. Passing through 113, the light is collided with the phosphor 201 coated on the panel 114 to emit light.

Here, the shadow mask 113 is used for color discrimination of the electron beam 112 from each of the R, G, and B electron guns, and the shadow mask 113 is formed of small holes 202. When the electron beam 112 emitted from the cathode is irradiated onto the phosphor 201, the electron beam 112 blocks and reflects the electron beam 112, thereby controlling the amount of the electron beam 112 irradiated.

That is, the hole 202, through which the electron beam 112 passes, formed in the shadow mask 113 is formed smaller than the size of the phosphor to be irradiated, so that only a portion of the electron beam 112 passes through the hole 202, The remainder is landing on the shadow mask 113 to adjust the amount 301 of the electron beam 112 irradiated to the phosphor.

In addition, as described above, the hole 202 through which the electron beam 112 formed in the shadow mask 113 passes is formed to be smaller than the size of the phosphor to be irradiated, whereby the center of the electron beam 112 and the phosphor 201 to be irradiated. Even if the center of the beam does not coincide with each other, the same amount of 301 electron beam 112 is irradiated to the phosphor 201 when the center of the beam does not coincide with each other so that the center does not coincide with the coincidence of the center. The degree of light emission of the phosphor 201 can be made equal (see FIGS. 3A and 3B).

Meanwhile, the electron beam 112 landing on the shadow mask as described above reaches 80% of the irradiated electron beam 112, and only the remaining 20% 301 passes through the hole 202 of the shadow mask 113. The phosphor 201 is irradiated. Accordingly, the temperature of the shadow mask 113 is increased by the electron beam 112 irradiated to the shadow mask 113, thereby causing thermal expansion of the shadow mask 113, thereby causing a dominant phenomenon in which the shadow mask 113 swells. Cause.

In addition, the domming phenomenon causes a mislanding phenomenon in which the electron beam 112 is not irradiated to the phosphor 201 accurately, resulting in a phenomenon in which color purity is reduced.

Thus, as a conventional technique for solving the above problems, to form an electron reflection film on the surface irradiated with the electron beam 112 of the shadow mask 113 with bismuth oxide (Bi ₂ O ₃ ) or the like to the shadow mask 113. There is a way.

In addition, the method of forming a coating film by printing by forming a slurry by spraying or high viscosity using an electron reflecting material, a glass component, an appropriate amount of water, etc. have.

However, forming the electron reflecting film of bismuth and the glass component has an electron reflecting effect, but when spraying 5 mg / cm 2 or more of the electron reflecting film, clogging of the holes formed in the shadow mask occurs, It is difficult to implement, and forming an electron reflection layer containing the tungsten, lead, bismuth, etc., the electron reflection effect is weakened when the layer is formed to a thickness of 2 ~ 3㎛, the electron reflection when formed to a thickness of 10㎛ Although the effect is well seen, when the thickness of the electron reflection layer is formed to 4 μm or more, a phenomenon occurs in which a hole of the shadow mask 113 is clogged, and thus its application is difficult.

In addition, a method of forming a coating film by evaporation using tungsten includes tungsten in a heat treatment process of a shadow mask and a frit sealing process in which the panel 114 and the funnel 109 are combined at a high temperature. When oxidized and dropped by this tungsten oxide, the peeling phenomenon which produces a vacancy generate | occur | produces, and when the peeling phenomenon is severe, the phenomenon which the part of the coating film which fell apart closes the hole of a shadow mask will also fall and the function of a shadow mask will fall. There is a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and by forming an electron reflection film that effectively reflects electrons to the electron beam irradiated to the shadow mask of the color cathode ray tube, and thereby effectively reduces thermal expansion, doming the shadow mask It is an object of the present invention to provide a shadow mask for color cathode ray tubes that can suppress the phenomenon and improve the color purity of the cathode ray tube.

1 is a schematic view of a typical colored cathode ray tube.

2 is an enlarged view of a shadow mask and a panel portion of a color cathode ray tube.

3 shows a phosphor of a panel and an electron beam reaching the phosphor;

4 is a view showing a process of forming an electron reflection film of the shadow mask for cathode ray tubes according to the present invention.

<Explanation of symbols for the main parts of the drawings>

101 ... Stempin 102 ... Cathode

103 to 108 ... First electrode to sixth electrode

109 ... Funnel 110 ... Shield Cup

111 ... deflection yoke 112 ... electron beam

113, 407 shadow mask 114 panel

201 ... phosphor 202 ... hole

401 ... printed board 402 ... frame

403 ... screen mesh 404 ... paste

405 ... scraper 406 ... squeegee

In order to achieve the above object, the shadow mask for color cathode ray tube according to the present invention, in the color cathode ray tube comprising a shadow mask having an electron reflection film, the electron reflection film formed on the surface to which the electron beam of the shadow mask is irradiated electron beam And a dominant reducing material configured to select at least one of mullite or silicon carbide as an electron reflection material and a heat reflection material for reflecting the light.

Here, the electron reflecting material is preferably contained at least one selected from tungsten or bismuth.

In addition, the electron reflection material is contained 10 ~ 33wt% of the dominant reducing material, the heat reflection material is preferably contained 47 ~ 70wt% of the dominant reducing material.

The electron reflection film is preferably formed by a screen printing method.

According to the present invention, it is possible to suppress the doming phenomenon due to thermal expansion by the electron beam irradiated to the shadow mask to effect the irradiation of the effective electron beam to improve the color purity.

As described above, when the electron beam radiated from the cathode in the cathode ray tube is irradiated to the phosphor, the shadow is partially blocked and reflected by the shadow mask to adjust the amount of the irradiation so that the phosphor emits light at a constant brightness. In this case, the shadow mask reflects the irradiated electron beam and undergoes thermal expansion by the irradiated electron beam. Such thermal expansion causes a dominant phenomenon in which the shadow mask swells to block and reflect the electron beam. It lowers and makes irradiation of an electron beam unstable, and the color purity of the fluorescent substance which light-emits by the electron beam irradiated is reduced.

Therefore, by forming an electron reflecting film formed on the surface irradiated with the electron beam of the shadow mask to reduce the effective electron reflection, thereby reducing the thermal expansion of the shadow mask by the electron beam irradiated thereby to make the irradiation of a stable electron beam to the phosphor to achieve a color purity Can be improved.

Here, the electron reflecting film includes a domming reducing material for exerting the effect, which is an electron reflecting material for effectively reflecting electrons according to its function and a heat reflecting material for reducing thermal expansion by irradiation of an electron beam. It is distinguished by.

The electron reflecting material is configured to include at least one of bismuth or tungsten, the content is preferably made of 10 ~ 33wt% of the dominant reducing material, the heat reflecting material is silicon dioxide (SiO ₂ ) and alumina (AL ₂ At least one of mullite or silicon carbide composed of O ₃ ) is selected and included, and the content thereof is preferably 47 to 70% of the dominant reducing material.

That is, the contents of the two components of the dominant reducing material, the electron reflecting material and the heat reflecting material have a relative relationship with each other. For example, when bismuth or tungsten as the electronic reflecting material is 10wt%, silicon carbide or mullite as the heat reflecting material is 70wt%. When bismuth or tungsten as the electron reflecting material is 33 wt%, silicon carbide or mullite as the heat reflecting material is 47 wt%.

Mullite is a chemical combination of alumina (Al ₂ O ₃ ) and silicon oxide (SiO ₂ ), the melting point of which is a stable crystal at 1850 ° C. is produced by the heating of clay, high fire resistance and high mechanical strength Therefore, it exhibits a stable effect as a heat reflection material.

In addition, when the electron reflection film is formed using the mullite or silicon carbide (SiC), the bonding force is enhanced by the silicon (Si) component included therein, so that the peeling phenomenon as in the prior art is eliminated even after the blackening process.

The electron reflection film as described above is preferably formed by a screen printing method, which will be described in detail with reference to the accompanying drawings.

4 is a view illustrating a process of forming an electron reflection film of a shadow mask for a cathode ray tube according to the present invention.

First, a screen mesh 403 having a reticulated structure with both ends fixed to the frame 402 is positioned on the printed board 401.

In addition, the printing ink used in the screen printing method is composed of a solvent for imparting flexibility to improve workability, a glass raw material and a dope reducing material for enhancing the bonding force, the solvent and the glass raw material, and the present invention. In order to reduce the electronic reflection and thermal expansion of the purpose, the dominant reducing agent is put together in a roll-mill and uniformly mixed for 2 hours or more using a disperser.

Here, the solvent serves to adjust the viscosity and concentration of the ink in order to facilitate the printing process, the glass raw material is printed on the shadow mask 407 after printing the printing ink for forming an electron reflection film, When the blackening process is performed at 600 ° C., it is completely vitrified to serve to bond the above-mentioned electron reflection film well and to firmly attach the electron reflection film to the shadow mask.

Then, a shadow mask 407 is placed between the printed circuit board 401 and the screen mesh 403, and a paste composed of printing ink in which a solvent, a glass raw material, a dominant reducing material, etc. are well mixed on the screen mesh 403. 404 is evenly applied to the screen mesh 403 using a scraper 405, and the paste 404 is again applied with a uniform pressure using a squeegee 406, while the screen mesh 403 is applied. Swipe in between to print as desired.

Here, the printing ink is formed of particles of the size of 3 ~ 5㎛, the screen mesh 403 is 5 ~ 6㎛ of slightly larger than that in order to pass through the printing ink particles of the size of 3 ~ 5㎛ It is made of gaps.

After the printing ink is applied on the shadow mask 407, the shadow mask 407 is blackened at about 600 ° C. to form an electron reflection film.

Such an electron reflection film effectively reflects electrons, and can effectively reduce thermal expansion of the shadow mask by irradiation of an electron beam.

As described above, the shadow mask for the cathode ray tube according to the present invention forms an electron reflection film on the surface to which the electron beam of the shadow mask is irradiated to effectively reflect the electron beam, and thus the doming phenomenon due to thermal expansion of the shadow mask by the electron beam irradiated accordingly. By suppressing the stably the electron beam is irradiated to the phosphor, there is an advantage that can improve the color purity of the phosphor.

Claims (5)

In the color cathode ray tube comprising a shadow mask having an electron reflection film, The electron reflecting film formed on the surface to which the electron beam of the shadow mask is irradiated comprises a color reflecting material comprising an electron reflecting material reflecting the electron beam and a domming reducing material formed by selecting at least one of mullite or silicon carbide as a heat reflecting material. Tolerant shadow mask. The method of claim 1, The electron reflection material is a shadow mask for color cathode ray tube, characterized in that at least one selected from tungsten or bismuth. The method according to claim 1 or 2, The shadow reflector for the color cathode ray tube, characterized in that the electron reflection material is contained 10 ~ 33wt% of the dominant reducing material. The method of claim 1, The heat reflection material is a shadow mask for color cathode ray tube, characterized in that containing 47 ~ 70wt% of the dominant reducing material. The method of claim 1, The electron reflection film is a shadow mask for color cathode ray tube, characterized in that formed by the screen printing method.