JP2854642B2 - Cathode ray tube device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a cathode ray tube device, and in particular, to an electron gun by rapidly eliminating static electricity generated near a high voltage electrode of an electron gun. The present invention relates to a cathode ray tube device that stabilizes a beam trajectory and improves withstand voltage characteristics.

(Prior Art) Conventionally, it is known to provide a conductive film inside and outside a funnel portion of a cathode ray tube device. The internal conductive film is provided for applying a high voltage for guiding the electron beam emitted from the electron gun to the panel unit, and the external conductive film is provided for forming a high-voltage smoothing capacitor. As described above, since a high voltage is applied to the cathode ray tube device, a discharge occurs in the high voltage portion when the power switch is turned on or during operation, and a circuit element such as a cathode electrode, a heater electrode, or a transistor is generated by the discharge current. There was a defect that destroyed. To prevent such a drawback, Japanese Patent Laid-Open No.
No. 9358, forming a semiconductor film electrically connected to an external conductive film,
As disclosed in Japanese Patent No. 39, a method of changing the resistance value of an internal conductive film has been proposed. In other words, by using the conductive film as a kind of resistive film, the discharge current in the high voltage part is suppressed, and the peripheral circuit is prevented from being damaged.

Usually, the electron gun structure of the cathode ray tube device is ideally designed so as to concentrate on the center of the phosphor screen when the electron beam is not deflected. However, in practice, it is necessary to provide a cathode ray tube with an appropriate means for correcting the above-mentioned concentration error due to an allowable error or an assembly error in manufacturing the cathode ray tube and related parts. Therefore, in the manufacturing process of the cathode ray tube device,
After the electron gun is sealed to the neck, the deflection device is inserted, the mounting position of the deflection device, such as the tube axis and the radial position, is adjusted, and further, as shown in JP-B-51-45936, the It is necessary to mount a color purity adjusting ring magnet for magnetically adjusting the tube axis. Since the operation of adjusting the position of the electron beam and the color purity (hereinafter abbreviated as ITC operation) is mainly performed while operating the cathode ray tube device, static electricity is generated at the neck when the power switch is turned on. The static electricity induced on the surface of the neck glass is described in Japanese Patent Application Laid-Open No. Sho 59-1714.
It cannot be completely solved even by the method of JP-A-39. FIG. 5 shows the charge distribution in the neck portion at the moment when the cathode ray tube device is turned on. In FIG. 5, the horizontal axis represents the distance in the tube axis direction from the end of the external conductive film. The peak of the charge distribution in FIG. 5 is near the focusing electrode of the electron gun. FIG. 6 schematically shows the state of the charge. As shown in FIG. 7, the static electricity at the neck is attenuated with the passage of time due to spontaneous discharge, and a change in the charge distribution means that the trajectory of the electron beam becomes unstable. If the ITC work is performed in such a state, it is necessary to perform readjustment when the static electricity is eliminated, which leads to deterioration of work efficiency. Further, as disclosed in JP-A-53-98773, a high-resistance layer is formed in a region located on the surface side of the envelope of the deflecting device, and this high-resistance layer is electrically connected to a low-resistance layer in a funnel portion. However, if the insulating film of the horizontal deflection coil of the deflection device is incomplete, there is a possibility that a large current leaks.

(Problems to be Solved by the Invention) The present invention enhances the efficiency of ITC work by quickly eliminating the static electricity that makes the trajectory of the electron beam unstable, and furthermore, the occurrence of a large current leak. An object of the present invention is to obtain a cathode ray tube device without fear.

[Constitution of the Invention] (Means for Solving the Problems) In the present invention, for the above purpose, a panel portion having a fluorescent screen formed on an inner surface thereof, a neck portion having an electron gun opposed to the fluorescent surface mounted therein, At least a funnel portion that couples the panel portion and the neck portion, and a deflecting device attached to an envelope portion from the funnel portion to the neck portion, and an inner conductive film on the inner surface of the funnel portion on the outer surface. In the cathode ray tube device in which the external conductive film is formed, the region from the region near the electron gun on the outer surface of the neck portion to the external conductive film in the funnel portion is intermittently changed from a high-resistivity semiconductor film to a low-resistivity semiconductor film. A plurality of semiconductor films are formed, and a predetermined interval is provided between the plurality of semiconductor films and between the semiconductor film and the external conductive film.

(Function) The electric charge induced in the neck glass near the focusing electrode of the electron gun is concentrated on the semiconductor film having a specific resistivity formed near the focusing electrode of the electron gun, and the electric charge is passed through a plurality of steps. The static electricity can be rapidly eliminated by moving the electron beam to the external conductive film, and a stable electron beam trajectory can be obtained. In addition, since a predetermined interval is provided between the plurality of semiconductor films, it is possible to prevent the occurrence of current leakage at a portion where the horizontal deflection coil of the deflection device contacts without hindering the movement of the electric charge. It is.

(Example) Hereinafter, an example of the present invention will be described.

Embodiment 1 An embodiment of the present invention will be described with reference to FIG. 1 and FIG. FIG. 1 is a cross-sectional view showing an overall configuration of an embodiment in which the present invention is applied to a color cathode ray tube, and FIG. The panel (1), the funnel-shaped funnel (3) and the neck (2) form a vacuum envelope. A phosphor screen (4) is formed on the inner surface of the panel (1), and three necks (2) are arranged in a line along the horizontal axis of the panel (2) on the neck (2). An in-line type electron gun (5) for emitting an electron beam is provided. A shadow mask (11) is supported and fixed by a mask frame (12) at a position close to and opposed to the phosphor screen. Here, an inner conductive film (7) is formed on the inner surface of the funnel portion (3), and an outer conductive film (8) is formed on the outer surface. In such a color cathode ray tube, a deflecting device (9) is inserted in a portion from the funnel portion (3) to the neck portion (2). In the above color cathode ray tube, an external conductive film (8) of the funnel portion (3) from a region near the focusing electrode (6) of the electron gun (5) on the outer surface of the neck portion (2).
To form a plurality of semiconductor films (10) intermittently from high resistivity to low resistivity, and between the plurality of semiconductor films and between the semiconductor film (10) and the external conductive film (8). At predetermined intervals. That is, a semiconductor film (10.1) having a resistivity of 10 ^{9 to} 10 ⁸ Ωm is formed near the focusing electrode (6) of the electron gun, and the semiconductor film (10.1) having a high resistivity is directed toward the external conductive film (8). Then, a plurality of semiconductor films having a film width of 10 mm are formed at intervals of 5 to 15 mm so that the resistivity gradually approaches the resistivity of the external conductive film (8) of 10 to 10 ² Ωm. The number of semiconductor films to be formed is such that the distance from the neck portion (2) to the external conductive film (8) can be formed with the above-mentioned film width and interval. At this time, the change in the resistivity of the semiconductor film depends on the oxidation contained in the graphite. Adjust by changing the amount of iron. In addition, there are two methods of forming a film, a spray method and a brush coating. The spray method is more advantageous in terms of uniformity of the film. In the embodiment shown in FIG. 2, the resistivity of the semiconductor film (10.1) is 10 ^{9 to} 10 ⁸
Ωm, the resistivity of the semiconductor film (10.2) is 10 ^{8 to} 10 ⁷ Ωm, the resistivity of the semiconductor film (10.3) is 10 ^{7 to} 10 ⁶ Ωm, and the resistivity of the semiconductor film (10.4) is 10 ^{6 to} 10 ⁵ Ωm. Was changed to become In addition, for example, the change in resistivity from the semiconductor film (10.1) to the semiconductor film (10.4) between a plurality of semiconductor films is set to 10 ⁸ Ωm, 10 ⁶ Ωm, 10 ⁵ Ωm, and 10 ⁴ Ωm. If it is changed discontinuously, the movement of electric charges will be locally sharp, causing local electric charge concentration, causing cracks in the glass at the neck and causing a decrease in the degree of vacuum (hereinafter abbreviated as neck penetration). Is not preferred.

Next, the semiconductor film thus formed intermittently (10)
The operation of will be described. As shown in FIG. 5, in the charge distribution of the neck portion at the moment when the cathode ray tube device is turned on, the origin corresponds to the end of the external conductive film (8) of the funnel portion (3), and this portion is connected to the ground. Since they are connected, the charge distribution is zero. The peak of the charge distribution occurs near the focusing electrode (6) of the electron gun. By forming this charge intermittently in a plurality of semiconductor films (10),
As a first step, the semiconductor film (10.1) formed on the neck portion near the focusing electrode of the electron gun is concentrated, and this is sequentially passed through a plurality of steps as shown in FIG. The static electricity is eliminated by moving the semiconductor film to a lower semiconductor film and finally to the external conductive film (8). At this time, by gradually changing the resistivity of the semiconductor film (10) formed intermittently from the neck portion (2) to the external conductive film (8), electric charges can be smoothly led to the ground. FIG. 4 shows the change over time of the charge distribution in the neck portion (2) according to the embodiment of FIG. 2, which is faster than FIG. 7 showing the change over time of the charge distribution in a conventional cathode ray tube device. It can be seen that the static electricity has been eliminated. In addition, the reason why the semiconductor film is intermittent is that the horizontal deflection coil of the deflection device (9) comes into contact with the portion where the semiconductor film is formed. This is because if the insulation is insufficient, a large current leak may occur.

In the above embodiment, the interval between the semiconductor films is made uniform, but this interval may be changed. In this case, although not shown, the interval on the electron gun side may be set as large as about 20 mm, and the interval on the external conductive film side may be set as small as about 5 mm.

Embodiment 2 Another embodiment of the present invention will be described. Since the overall configuration of this embodiment is the same as that of the first embodiment, a detailed description is omitted. In Example 2, moisture is absorbed and water is absorbed from a region of the outer surface of the neck portion (2) near the focusing electrode (6) of the electron gun (5) to the external conductive film (8) of the funnel portion (3). The resistivity at the time of forming a plurality of polymer films intermittently from a low hygroscopic to a high polymer film that becomes a semiconductor region, substantially changing from high resistance to low resistance,
Further, a predetermined interval is provided between the plurality of hygroscopic polymer films and between the hygroscopic polymer film and the external conductive film (8). By absorbing moisture in the air, the hygroscopic polymer film lowers its resistance value and can function as a semiconductor film. That is, in this embodiment, a hygroscopic polymer film is used as a means for changing the resistivity. Those having high hygroscopicity act as low resistance, and those having low hygroscopicity act as high resistance. The function of transferring electric charges between the plurality of hygroscopic polymer films is the same as in the first embodiment, and a detailed description is omitted.

In the above embodiment, the polymer film is used as the hygroscopic semiconductor. However, the semiconductor film is not limited to the polymer film and has a hygroscopic property and the resistance value when absorbing moisture is within the range of the resistance value shown in the first embodiment. Any function can be used as long as it functions.

Example 3 As another means for changing the resistivity by using a hygroscopic semiconductor film, by changing the film width of a plurality of films having the same hygroscopic property from a large one to a small one, a substantially high resistance can be obtained. The resistance may be changed from low to low. Since there is no need to change the hygroscopicity for each film as compared with Example 2,
This is advantageous in cost.

Needless to say, the hygroscopic semiconductor film is not limited to the polymer film as in the second embodiment.

In the second and third embodiments, the distance between the films may be changed as in the first embodiment.

[Effects of the Invention] As described above, the semiconductor film is intermittently formed by sequentially lowering the resistivity from the neck portion to the external conductive film in the funnel portion, so that the static electricity generated near the focusing electrode of the electron gun is locally reduced. It is possible to quickly resolve the problem without causing neck penetration due to electrical charge concentration. Further, since an interval is provided between the semiconductor films, it is possible to prevent current leakage from the deflection device.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a cathode ray tube device of the present invention,
FIG. 2 is a partially enlarged cross-sectional view showing the state of formation of the semiconductor film in FIG. 1, and FIGS. FIG. 4 is a graph showing the temporal change of the charge distribution at the neck portion in the embodiment of the present invention, FIG. 5 is a graph showing the charge distribution at the neck portion of the conventional cathode ray tube device, and FIG. FIG. 7 is a schematic cross-sectional view showing a charging state of a neck portion of the tube device, and FIG. 7 is a graph showing a temporal change of a neck portion charge distribution in a conventional cathode ray tube device. (1) Panel (2) Neck (3) Funnel (4) Phosphor screen (5) Electron gun (6) Focusing electrode (7) Internal conductive film (8) ... external conductive film (9) ... deflection device (10) ... semiconductor film (11) ... shadow mask (12) ... mask frame

Claims (1)

(57) [Claims] 1. A panel portion having a fluorescent screen formed on an inner surface thereof, a neck portion having an electron gun opposed to the fluorescent surface mounted therein,
At least a funnel unit connecting the panel unit and the neck unit, and a deflecting device attached to an envelope part from the funnel unit to the neck unit, wherein an inner conductive film is formed on an inner surface of the funnel unit by an outer surface. In the cathode ray tube device in which an external conductive film is formed on the external conductive film of the funnel portion from the region near the electron gun on the outer surface of the neck portion, the resistivity is sequentially and intermittently changed from a high resistivity to a low resistivity. A plurality of semiconductor films, wherein a predetermined interval is provided between the plurality of semiconductor films and between the semiconductor film and the external conductive film.