KR100258993B1 - Shadow mask type color crt and manufacture thereof - Google Patents

Abstract

PURPOSE: A shadow mask type color braun tube and manufacturing method thereof is provided to prevent deterioration of color purity and to improve doming phenomenon by forming electron absorption film inside inner shield. CONSTITUTION: An inside surface of panel(10) is sprayed with fluorescent film photo-emitting red, green, blue separately. Funnel is melted and adhered closely with above panel(10) and maintains inside part in state of vacuum. Electron gun is sealed with neck part of above funnel and scans electron beam. Shadow mask(40) is installed near to and opposite against above fluorescent film. Deflection yoke deflects above electron beam. Inner shield(100) is formed to be opposite against above shadow mask(40), and blackening film and electron absorption film(101) is formed inside surface of inner shield. Above electron absorption film(101) is black aluminum coating film.

Description

Shadow mask type color brown tube and manufacturing method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a shadow mask type color CRT and a method of manufacturing the same, and in particular, to form an electron absorbing film on the inner side of an inner shield so as to reduce the doming shape. A shadow mask type brown tube and a manufacturing method thereof are provided.

As shown in FIG. 1, a conventional shadow mask type color brown tube is a screen panel in which a dot or stripe type fluorescent film 11 emitting red, green, and blue light is applied to an inner surface thereof. 10), a funnel 20 which is hermetically fused to the rear end of the screen panel 10 to keep the inside in a vacuum state, and is enclosed in a cylindrical neck portion 21 of the funnel 20 to be electron beam 31 A shadow mask 40 which is arranged so that an electron gun 30 for scanning the electron beam 30 and a plurality of apertures corresponding to a dot or a stripe of the fluorescent film 11 are arranged in close proximity to the fluorescent film 11; A deflection coil 50 for deflecting the electron beam 31 so that the entire surface of the fluorescent film 11 can be sanded through the aperture, and a blackening film is formed to face the shadow mask 40. It consists of the inner shield 60 shaped so that it may become.

In the drawing, reference numeral 71 denotes a stud pin fixed to the screen panel 10, 72 denotes a frame supporting the shadow mask 40 and an inner shield 60, and 73 denotes the stud pin 71. It is a spring that the frame 72 is fixedly supported.

Referring to the first diagram attached to the operation of the conventional shadow mask-type color-brown tube configured as described above is as follows.

First, the electron flow is controlled by the signals of three primary colors in three electron guns 30 corresponding to three primary colors, and the individual electron beams 31 are scanned.

At this time, when a current flows in the deflection coil 50 placed on the neck portion 21, the electron beam 31 is deflected at a wide angle by this magnetic field.

The deflected electron beam 31 is converged to a plurality of apertures arranged corresponding to the dots of the fluorescent film 11 in the shadow mask 40.

Then, the electron beam 31 collides with the red, green, and blue dots of the fluorescent film 11 corresponding to the respective apertures, and emits light. The red phosphor in the red beam, the green phosphor in the green beam, and the blue The blue light emits blue phosphors.

At this time, the electron beam 31 that strikes the fluorescent film 11 and reproduces the image corresponds to about 20% of the total scanning amount of the electron gun 30, and the remaining about 80% of the electron beam 31 is a shadow mask ( 40), causing a temperature rise.

As a result, the shadow mask 40 is thermally expanded to cause a swelling phenomenon in which the surface thereof swells.

Then, the corresponding position between the aperture of the shadow mask 40 and the dot of the fluorescent film 11 is changed, so that the mislanding amount of the electron beam 31 is increased, so that the color purity is reduced.

In order to solve such a color purity degradation, "Korean Patent Publication No. 90-3951" has potassium silicate (K ₂ ) mainly composed of bismuth oxide (Bi ₂ O ₃ ) or tungsten (WO ₃ ) having good heat radiation and electron reflecting ability. SiO ₃ , potassium silicate), and a pure water (slurry) was prepared and then sprayed in multiple layers on the surface where the electron beam 31 is incident in the shadow mask 40 to form a film.

In this way, the manufacturing process of the spray-coated shadow mask 40 is performed by mask molding → blackening → MR welding (welding of mask and frame), SR welding (welding of spring and frame) → mask stabilization heat treatment → phosphor coating → baking → CMA. (Coated mask assembly) in the panel and the mask is separated after the spray coating is made.

In the blackening process, the shadow mask 40 forms a blackening film in a modified gas atmosphere in which LPG is burned, and has a thermal radiation function and an oxidation preventing function.

The spray coating process is to coat the suspension on the surface of the shadow mask 40 so that when the electron beam 31 injected from the electron gun 30 impinges on the shadow mask 40, the kinetic energy of the electrons is converted into thermal energy. It has a thermal radiation function and an electron reflection function that scatters backward while preventing the conversion to thermal energy after the impact on the shadow mask 40.

However, bismuth oxide (Bi ₂ O ₃ ) of the conventional shadow mask coating has a weak electron reflecting function, tungsten (WO ₃ ) has a problem that does not effectively improve the doming phenomenon of the mask because the thermal radiation function is weak.

Therefore, the present invention has been proposed to solve the above problems of the prior art, to provide a shadow mask type color brown tube and a method of manufacturing the same to form an electron-absorbing film on the inner surface of the inner shield to reduce the dominant characteristics. There is this.

The technical means of the present invention for achieving the above object is a panel coated with a fluorescent film that emits red, green, and blue, respectively, on the inner surface, and a funnel that is hermetically fused to the panel to keep the interior in a vacuum state, and An electron gun encapsulated in the neck of the funnel to scan the electron beam, a plurality of apertures corresponding to the red, green, and blue dots of the fluorescent film are arranged so that the shadow mask is installed close to the fluorescent film, and the electron beam is fluorescent through the aperture. The deflection coil is deflected so as to be able to sand the entire surface of the film, and the element coil shielding the geomagnetism is combined, and an inner shield formed to face the shadow mask by forming a blackening film and an electron absorbing film on the inner surface thereof.

On the other hand, the manufacturing process of the inner shield is characterized in that it comprises the steps of forming the inner shield, forming a blackening film on the inner shield, and forming an electron absorbing film on the inner surface of the inner shield.

1 is a cross-sectional view of a conventional shadow mask type color brown tube.

Figure 2 is a detailed configuration of the main portion of the shadow mask-type color-brown tube according to the present invention.

3 is a manufacturing process diagram of the inner shield according to the present invention.

Figure 4 is a graph of the doming characteristic contrast of the color tube according to the prior art and the present invention.

* Explanation of symbols for main parts of the drawings

100: inner shield 101: electron absorption film

Hereinafter, the present invention will be described with reference to the accompanying drawings.

2 is a detailed configuration diagram of the shadow mask type color brown tube according to the present invention, wherein the electron absorption film 101 is formed on the upper surface of the blackening film formed on the inner surface of the inner shield 100.

In one embodiment, the electron absorption film 101 is applied with a black aluminum (black AL) coating film excellent in the electron absorption function.

When explaining the overall configuration by adding the main configuration diagram of the color brown tube shown in FIG. 2 to the cross-sectional view of the color brown tube shown in FIG. 1, a dot or star life type fluorescent film that emits red, green, and blue light respectively ( 11) a screen panel 10 coated on the inner surface, a funnel 20 which is hermetically fused to the rear end of the screen panel 10 to keep the inside in a vacuum state, and a cylindrical neck of the funnel 20. The electron gun 30 encapsulated in the portion 21 and scanning the electron beam 31 and a plurality of apertures corresponding to dots or stripes of the fluorescent film 11 are arranged to face the fluorescent film 11 in close proximity. A shadow mask 40 provided, a deflection coil 50 for deflecting the electron beam 31 so that the entire surface of the fluorescent film 11 can be quadrupled through the aperture, and a blackening on the inner surface. A film (not shown) and the electron absorption film 101 is formed to the shadow mask 40 It is comprised by the inner shield 100 shape opposed to the.

Meanwhile, as illustrated in FIG. 3, the inner shield 100 may be manufactured in the order of inner shield molding → blackening film formation → electron absorption film formation (aluminum deposition) → assembly to a mask assembly → frit sealing.

The electron absorption film forming process is divided into a high vacuum aluminum deposition step and a low vacuum aluminum deposition step when using aluminum as an example of the coating material. That is, after first depositing aluminum in high vacuum (10E-6 to 10E-7 Torr), the electron absorption film 101 is formed by redepositing aluminum in low vacuum (10E-2 to 10E-3 Torr).

Therefore, the shadow mask type color brown tube of the present invention that has undergone such a manufacturing process has an inner shield when about 80% of the total scanning amount of the electron beam 31 scanned by the electron gun 30 is reflected from the coating layer of the shadow mask 40. The electrons reflected from the electron-absorbing film 101 formed on the inner side of the 100 are effectively absorbed.

Therefore, the temperature rise of the shadow mask 40 due to scattering and convection of heat in the CRT is reduced again.

Table 1 below is a comparative data of the prior art and the present invention through the experiment.

However, the experimental conditions are 1) The mask is made of AK steel, and is coated with bismuth oxide (Bi ₂ O ₃ ) thereon. 2) The inner shield is made of low carbon steel containing less than 0.005 wt% carbon.

As shown in the experimental data of Table 1, the electron reflection coefficient is maintained at a low level of 0.2 and the thermal radiation coefficient is also maintained at a low level of 0.6 so that the electrons reflected from the coating layer can be effectively absorbed by the electron absorption film 101. Will be.

As described above, the doming characteristic of the color brown tube to which the inner shield 100 formed on the inner surface of the electron absorption film 101 coated with black aluminum is applied is shown in the control graph of FIG.

As can be seen from the graph shown in the drawing, when the cathode ray tube is initially driven, the shadow mask expands due to the action of the electron beam, and initially shows the highest mislanding value, and thereafter, it is somewhat stabilized by the action of the frame and the spring, so that a constant mislanding state is achieved. It continues.

In this case, as shown in FIG. 4, the present invention improves the initial mislanding peak value (a) by about 25% and the mislanding amount (c) after the stabilization is also improved by about 33%, compared to the prior art. It can be seen that time (b) is also significantly reduced.

As described above, the present invention forms an electron absorbing film on the inner side of the inner shield and absorbs the electrons reflected from the coating layer of the shadow mask, thereby improving the doming property and preventing the color purity from being lowered.

Claims (4)

A panel coated with a fluorescent film emitting red, green, and blue light on the inner surface, a funnel which is hermetically fused to keep the inside of the panel in a vacuum state, an electron gun encapsulated in the neck portion of the funnel, and scans an electron beam; And an inner shield formed so as to face the shadow mask by forming a shadow mask disposed to face the fluorescent film, a deflection coil deflecting the electron beam, and a blackening film and an electron absorbing film formed on an inner surface thereof to face the shadow mask. Shadow mask type color brown tube to say. The shadow mask type color tube according to claim 1, wherein the electron absorption film is a black aluminum coating film. In a shadow mask type color brown tube to which an inner shield for shielding a geomagnet is applied, the manufacturing process of the inner shield may include forming the inner shield, forming a black film on the inner shield, and forming the inner shield. Method of producing a shadow mask type color tube, characterized in that it comprises the step of forming an electron absorption film on the inner surface. [4] The method of claim 3, wherein the electron absorbing film forming step comprises depositing aluminum in a vacuum to form a film.