JPH0773030B2 - Method for manufacturing cathode ray tube - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a method for manufacturing a cathode ray tube.

(Prior Art) In general, an electron gun assembly incorporated in a cathode ray tube, for example, a color picture tube, has a dot-shaped or band-shaped electron beam deposited on the inner surface of the face plate, and thereby is divided into red, green, and blue. It consists of three electron guns corresponding to each of the phosphor layers that emit light, and the intensity of the electron beam emitted from these electron guns, that is, the reproduced image of the three primary colors of red, green, and blue light. Reproduction is the cathode of each electron gun, the first electrode,
This is performed by changing the voltage applied to the so-called three-pole portion composed of the second electrode.

Of these, the cathode, in particular, is heated to a high temperature by a built-in heater, and each component constituting the cathode is thermally expanded, and the distance between the electron emission surface of the cathode and the opposing surface of the first electrode is changed. This change in the interval occurs even when the temperature distribution of each component of the cathode is non-uniform depending on the arrangement method of the electron gun, that is, the delta type or the in-line type. The implantation of the metal support of each electrode on the insulating support glass is incomplete, or the method of fixing the cathodes to the cathodes and the first electrode to the insulating support glass on the first electrodes, that is, the shape of the metal support, etc. If they are different, a difference appears in the change in the distance between the cathode and the first electrode between the three electron guns together with the energization time. This is the difference in the intensity of the electron beams emitted from the three electron guns, and until the reproduced image reproduced on the face plate has an accurate color, drawing an undesired reproduced image on the way for several minutes. Currently, it takes several tens of minutes.

Next, in order to explain the above-mentioned phenomenon in more detail, changes in time and current (brightness) of the electron beam are shown in FIG. 4, the cathode and the structure near the first electrode are shown in FIG. 1, and the cathode is shown in FIG. And / or the relationship between the strip-shaped metal support of the first electrode and the insulating support glass is shown.

First, FIG. 4 shows an example of a relationship between time and electron beam current (brightness). That is, it shows a change in current when a predetermined voltage is applied to each electrode of a color picture tube having an electron gun structure in which the current is adjusted to (I) value together with three electron guns. Yes, for example, curve 1a changes the current of an electron gun that hits a red phosphor, curve 1b changes the current of an electron gun that hits a green phosphor, and curve 1c changes the current of an electron gun that hits a blue phosphor. Then, at T1 hour after energization, the current amount of each electron gun shown by these curves is 2
The screen becomes a, 2b, and 2c, and the screen is reddish but gradually bluish, and becomes stable in a predetermined color (or white at a desired color temperature) after T2 hours.

Next, referring to FIG. 1, the changing state of the distance between the cathode 5 and the first electrode 6 will be described.

First, the cathode 5 will be described.
The side cylinder 5b having the support cylinder 5d is supported by three suspension plates 5c.
Is supported in the top opening of the support cylinder 5d and the outer cylinder 5e.
Is fixed at the welding point 5g, and the outer cylinder 5e is fixed to the insulating support glass 7 via the strip-shaped metal support 5f. or,
The heating portion 4a of the heater 4 is arranged in the side cylinder 5b, and both ends thereof are fixed to holding members (not shown) planted in the insulating support glass 7 via the heater support 4b.

Next, the first electrode 6 has a substantially cap shape, and an electron beam passage hole 6b is formed in the bottom surface thereof, that is, in the center of the surface 6a opposite to the electron emission surface 5a of the cathode 5. The side surface 6c is fixed to the insulating support glass 7 via the strip-shaped metal support 6d.

Also, it will be explained that the second electrode (not shown) also has an electron beam passage hole on the surface opposite to the surface 6a of the first electrode 6 and is planted on the insulating support glass 7 via a strip-shaped metal support. There is no end.

The arrangement of, for example, the cathode 5 among the above electrodes will be described with reference to FIG. 2 while changing the reference numerals from FIG. 1, and the outer cylinder 10 of the cathode 5 corresponding to the phosphor layers emitting red, green and blue colors, respectively.
a, 10b, and 10c are arranged in a line, and four insulating supporting glasses 7a, 7b, 7c, and 7d are respectively provided with strip-shaped metal supports 11a and 1
The strip-shaped metal supports 11a, 11 are fixed via 1b, 11c.
Of the b and 11c, the outer cylinders 10a and 10c of the cathode 5 on both sides are supported by one metal support 11a and 11c which circumscribes about half the circumference of the outer cylinder 10b of the cathode 5 at the center. It has a structure supported by two metal supports 11b having a V shape.

By the way, when the electron gun assembly having the above-described structure is mounted in a color picture tube and a predetermined voltage is applied to each electrode for operation, when the switch is turned on, a current flows through the heater 4 and the heat generating portion 4a generates heat. As a result, the electron emission surface 5a of the cathode 5 is heated, and thermoelectrons are emitted from the electron emission surface 5a. The thermoelectrons are generated by the electric potential of the three-pole portion including the first electrode 6 and the second electrode, and the current of the electron beam is generated. It becomes a bundle and collides with the phosphor layer.

In this case, the cutoff voltage by the second electrode is inversely proportional to the distance between the first electrode 6 and the cathode 5, and it is known that the smaller the distance between the first electrode 6 and the cathode 5, the larger the current. .

Next, the heater 4 is turned on by turning on the switch described above.
Explaining the displacement of each component due to thermal expansion when the heat generating part 4a of the heater heats up, and the electron emitting surface 5a of the cathode 5 is heated, the side cylinder 5b extends due to heat generation of the heat generating part 4a of the heater 4, The emission surface 5a moves in a direction toward the first electrode 6.
Next, the hanging plate 5c extends, the electron emission surface 5a moves in a direction away from the first electrode 6, and then the support cylinder 5d extends, and further the outer cylinder
5e extends, but these movements are completed in a relatively short time due to the small heat capacity of each component. However, the metal support 5f to be heated next has a large heat capacity, and the warp and the extending direction are not constant due to the fusion state with the insulating support glass 7.

This is apparent from the difference in shape of the metal supports 11a, 11b, 11c shown in FIG.
Since the difference between the fixed states of b and 11c appears in correlation with the difference between the distance between the first electrode 6 and the cathode 5, the current curves 1a, 1b and 1c shown in FIG. 4 are drawn, There is a drawback that the quality of the reproduced image on the color picture tube is degraded.

(Problems to be Solved by the Invention) As a method of fusing a metal support to the above-mentioned insulating supporting glass, usually, an insulating supporting glass made of low alkali borosilicate glass called multi-form glass is used as a jig. Place on top of the metal support and heat it with a burner from above the surface where the metal support is planted, and in the softened state, pre-fix the metal support to each electrode placed at the desired position with a jig or spacer. Although pressure is applied, the temperature from the softened state of the insulating support glass to the pressure changes abruptly. For example, the softening temperature of multi-foam glass is about 820 ° C., and the fusing operation is heating at about 1300 ° C. for 20 to 30 seconds, and then the insulating support glass is pressure-welded. In this case, the insulating support glass is pressed at a temperature close to room temperature in a short time of 0.5 to 1.0 seconds, and the temperature of the multi-form glass drops in a short time. For this reason, undesired strain or deformation is applied to the metal support during implantation. Therefore,
When the heater is heated, the warp or extension direction of the metal support is not constant.

The present invention has been made in view of the above problems, and since it is difficult to remove undesired strain and deformation when implanting a metal support, the cathode ray tube is designed to remove the strain during exhaust of the cathode ray tube. It aims at providing the manufacturing method of.

[Structure of the Invention] (Means for Solving the Problems) In order to eliminate the above-mentioned distortion, the present invention controls the temperature for heating the electron gun electrode from the outside during the exhaust of the cathode ray tube of the insulating support glass of the electron gun. This is a method of manufacturing a cathode ray tube in which the temperature is higher than the softening temperature.

(Function) Multifoam glass, which is usually used as an insulating support glass, is softened at a softening temperature of about 820 ° C in order to remove the strain due to its characteristics, and after the metal support is planted, the strain point is about 10% until it is fixed. It is necessary to maintain 480 ° C. for a certain period of time, and in the usual method for implanting a metal support, it is difficult to remove the strain because it is rapidly fixed after the softening of the multi-form glass, but this invention is exhausted. By heating the inside of the electron gun electrode to a heating temperature higher than the softening temperature of the insulating supporting glass and holding it for a certain period of time, the strain of the insulating supporting glass is removed.

(Example) Hereinafter, a method of manufacturing a cathode ray tube according to the present invention will be described in detail with reference to FIG. In general, the exhaust of a cathode ray tube, for example, a color picture tube, is usually performed by the high-frequency induction heating coil 9 arranged on the outer periphery of the neck portion 8 simultaneously with the exhaust from the exhaust tube.
Thus, the first electrode 6 and the cathode 5 of the electron gun electrode are heated around the center to degas the respective electrodes. For heating the electron gun electrode, conventionally, the maximum temperature is about 750 ° C. and the temperature is raised and lowered for a certain period of time.

However, according to the present invention, the temperature of the portions of the metal supports 5f and 6d to which the cathode 5 and the first electrode 6 are fixedly embedded in the insulating support glass 7 made of borosilicate glass is the same. Higher than the softening temperature of 840 ℃
The evacuation condition is to heat at a maximum temperature for a certain period of time.

Although the temperature is set to about 840 ° C. in the above embodiment, the strain can be removed at a temperature higher than the softening point of the insulating support glass 7. Also, when it becomes higher than the metal evaporation temperature of the electrode,
There is a case where a vapor deposition film is formed on the inner surface of the neck portion 8 due to the evaporation, and it is desirable that the vapor deposition temperature is not higher than the metal vaporization temperature.

[Effects of the Invention] According to the present invention, the change in current when a predetermined voltage is applied to each electrode of the cathode ray tube is as shown in FIG. 3, which is red and green as compared with the conventional FIG. , The change in the current of each blue color is eliminated, and the time T3 until the color stabilizes in a predetermined color (or white at a desired color temperature) is also shorter than in the conventional case.
As a result, it is possible to provide an excellent color picture tube that does not cause color unevenness, and its industrial value is extremely large.

[Brief description of drawings]

FIG. 1 is a sectional view showing an electron gun assembly and a coil for heating an electrode during exhaust of a cathode ray tube, which are used for explaining a conventional method and a method for manufacturing a cathode ray tube (color picture tube) according to the present invention.
1 is a sectional view taken along the line AA 'in FIG. 1 and viewed in the direction of the arrow. FIG. 3 is a characteristic curve diagram showing the relationship between the current and time of each electron gun of the cathode ray tube according to the present invention. FIG. 4 is a characteristic curve diagram showing a relationship between current and time of each electron gun of a conventional cathode ray tube. 5 ... Cathode, 5f ... Metal support, 6 ... 1st electrode, 6d ... Metal support, 7 ... Insulating support glass, 9 ... Heating coil.

Claims (1)

[Claims] 1. A cathode ray tube provided with an electron gun in which a plurality of electrodes including a cathode and a first electrode are fixed to a part of a metal support, and the other part of the metal support is embedded in an insulating support glass. During high-frequency heating of the cathode and the first electrode during evacuation of, the portion of the metal support embedded in the insulating support glass is made higher than the softening point of the insulating support glass and is held for a certain period of time. A method of manufacturing a cathode ray tube, which comprises heating.