JPH0487236A - Cathode-ray tube - Google Patents

Abstract

PURPOSE:To easily apply a determined voltage to each electrode of an electron gun by connecting one end part of a resistance body provided along the electron gun to an electrode to which a relatively high voltage is applied, excluding an anode electrode, through a stem pin to resistively divide the voltage, and applying the determined voltage to an electrode to which a relatively low voltage is applied. CONSTITUTION:A resistance body 27 is provided along an electron gun 20, and one end part of the resistance body 27 is connected to, for example, an electrode G3 to which a relatively high voltage is applied, excluding an anode electrode G6, through a stem pin 24 to resistively divide the relatively high voltage applied to the electrode G3, and the resulting voltage is applied to electrodes G4, G5 to which a relatively low voltage is applied. Thus, a determined voltage is applied to one stem pin 24, whereby the voltage is resistively divided by the resistance body 24, and the determined voltage can be applied to other electrodes G4, G5. Thus, a required voltage can be easily applied to each electrode of the electron gun.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to a cathode ray tube, and in particular, a resistor is arranged along an electron gun, and the resistor divides the resistance of the electron gun. The present invention relates to a cathode ray tube in which a predetermined voltage is applied to a predetermined electrode of the cathode ray tube.

(Prior art) Cathode ray tubes that display images generally have a phosphor screen formed on the inner surface of the face plate of the envelope (in the case of color picture tubes, a phosphor screen is formed on the inner surface of the panel, and a phosphor screen is formed inside the neck of the envelope opposite to this phosphor screen). A structure in which an electron beam emitted from a disposed electron gun is deflected by a magnetic field generated by a deflection yoke attached to the outside of the envelope, and an image is displayed by scanning the phosphor screen horizontally and vertically. is formed.

Figure 4 shows the basic configuration of the electron gun. This electron gun has a cathode (K) and first to fourth grids (G1) to (G4) sequentially arranged from the cathode (K) in the direction of the phosphor screen, which are connected to a pair of insulating supports. (1) is formed into an integrally fixed structure. In this structure, the cathode (K) and the first to third
The grids (G1) to (G3) form an electron beam forming part (GEA) that controls electron emission from the cathode (K) and focuses the emitted electrons into an electron beam. By grid (G3) and (G4),
A main electron lens section (MLA) is formed which accelerates and focuses the electron beam emitted from the electron beam forming section (GEA) and forms an image on a phosphor screen.

The voltage applied to each electrode of this electron gun is applied to the fourth grid (
G4) includes an anode terminal provided in the cone part of the envelope,
The internal conductive film (2) is coated from this cone part to the inner surface of the adjacent neck part, and the anode is connected to the valve spacer (3) attached to the fourth grid (G4) and in pressure contact with this internal conductive film (2). A high voltage is applied to the other electrodes via a plurality of stem pins (5) which pass hermetically through the stem (4) sealing the neck end. The voltage applied to each electrode is such that the cathode (K) is set to a cutoff voltage of about 150V, a video signal is added to this, the first grid (Gl) is set to ground potential, and the second grid (G2) is set to 500V to 1kV. , third grid (G3
), 3 to 8 kV to 4th grid (G4), 25 to 30 kV to 4th grid (G4)
An anode high voltage of about V is applied.

By the way, in order to improve the resolution of a cathode ray tube, it is necessary to improve the performance of the electron gun, that is, the performance of the electron lens formed by each electrode. As a means to improve the performance of the electron lens, conventional methods include increasing the diameter of the electron beam passage hole in the electrode to form a large-diameter electron lens, or increasing the distance between the electrodes to form a long-focus electron lens with a gradual potential change. It is known to do.

However, in a cathode ray tube, since an electron gun is generally disposed within a narrow neck, there are geometrical limitations on increasing the diameter of the electron lens by increasing the diameter of the electron beam passage hole. Increasing the electrode spacing is also limited by the need to ensure that the focused electric field formed between the electrodes is not influenced by undesired electric fields in the neck.

Therefore, the distance between the third and fourth grids forming the main electron lens section is increased, and an intermediate electrode is provided between them.
Either keep this intermediate electrode at about 10 to 20 kV, which is between the voltages applied to the third and fourth grids, or
There is an electron gun that improves the performance of an electron lens by using a plurality of electrodes in addition to the fourth grid to form a composite electron lens in which the electrode potential is varied.

In any case, the voltage applied to each electrode of such an electron gun is applied via an internal conductive film coated on the anode terminal and the inner surface of the neck for the electrode to which the anode high voltage is applied, and for the other electrodes Among the electrodes to which a low voltage is applied, the voltage is applied via a plurality of stem pins that penetrate the stem sealing the neck end.

However, when a medium to low voltage is applied through the stem pins that pass through the stem, the withstand voltage between the stem pins increases because the multiple stem pins of the stem that seal the narrow neck end are placed close to each other. problem, and it is not possible to apply relatively high voltages or many different voltages.

Therefore, Japanese Patent Laid-Open No. 53-89360 discloses a means of disposing a resistor in the neck along the electron gun, dividing the anode high voltage applied to the above electrode by resistance, and supplying a predetermined voltage to the other electrodes.
This is shown in the issue of the publication, etc.

However, as the resistor that divides the anode high voltage is placed in a narrow neck as described above, it must have a large resistance value of several hundred to several thousand MΩ to reduce power consumption. Therefore, there is a problem in terms of reliability, and it is also difficult to accurately divide the voltage into a predetermined voltage. Furthermore, when a focus voltage is supplied through such a resistor, a variable resistor with extremely high resistance is required as a resistor for controlling the focus voltage, which is expensive. Further, there is a problem in that the electrode connected to the resistor cannot be used when measuring the gas inside the tube in the cathode ray tube manufacturing process.

(Problems to be Solved by the Invention) As mentioned above, in order to improve the resolution of a cathode ray tube, it is necessary to improve the performance of the electron gun, that is, the performance of the electron lens. It is desirable to have a composite electron lens structure. However, when trying to supply a predetermined voltage to each electrode of an electron gun with a composite electron lens structure through stem pins, the stem pins are placed close to each other, so the withstand voltage between the stem pins becomes a problem, and the voltage is relatively high. It is not possible to apply many different voltages. Therefore, regarding such an electron gun, there is a cathode ray tube in which a resistor is arranged along the electron gun, and the anode high voltage is resistance-divided by the resistor and supplied to a predetermined electrode. However, in general, the anode high voltage of cathode ray tubes is extremely high, at 25 to 30 kV, so the resistor that divides this anode high voltage must have a large resistance value to reduce power consumption. As a result, there are problems in terms of reliability, and it is also difficult to accurately divide the voltage into predetermined voltages. Furthermore, when a focus voltage is supplied through this resistor, a variable resistor with extremely high resistance is required as a resistor for controlling the focus voltage, which is expensive. Furthermore, when measuring the gas inside the tube during the manufacturing process of cathode ray tubes, problems arise in that the electrodes connected to the resistor cannot be used.

This invention was made in view of the above problems, and
An object of the present invention is to construct an electron gun with a structure that allows a predetermined voltage to be easily applied to each electrode of the electron gun, even if the electron gun has a composite electron lens structure in order to improve the resolution of a cathode ray tube.

[Structure of the Invention (Means for Solving the Problem) An electron gun having a cathode and a plurality of electrodes for controlling, accelerating and focusing an electron beam from the cathode onto a target, and an arrangement of the electron gun. In a cathode ray tube, the neck end of the envelope is hermetically sealed, and the cathode ray tube has a plurality of stem pins or a stem hermetically penetrated through which a predetermined voltage is applied to a plurality of electrodes of the electron gun. A resistor is arranged along the electron gun, and one end of the resistor is connected to one of the plurality of electrodes of the electron gun to which a relatively high voltage is applied, excluding the anode electrode, through the stem pin. Then, the relatively high voltage applied to this electrode is divided by resistance,
The structure is such that a predetermined voltage is applied to an electrode to which a relatively low voltage is applied.

(Function) As described above, a resistor is placed along the electron gun, and one end of the resistor is connected via a stem pin to an electrode to which a relatively high voltage is applied, except for the anode electrode. If we adopt a structure in which a relatively high voltage applied to the stem pin is divided by resistance and applied to the electrode to which a relatively low voltage is applied, by applying a predetermined voltage to one stem pin, the resistor A predetermined voltage can be applied to other electrodes by dividing the resistance. Moreover, since the voltage supplied via the stem pin is lower than the anode high voltage, the power consumption of the resistor is small (usually 10 to 40% of the anode high voltage), making it easy to manufacture and highly reliable. . Furthermore, since the resistance value can be reduced, a predetermined voltage can be applied accurately. Furthermore, if the electrode to which a relatively high voltage is applied is used for measuring the gas inside the tube in the cathode ray tube manufacturing process, the measurement of the gas inside the tube will not be a problem.

(Example) Hereinafter, the present invention will be described based on an example with reference to the drawings.

Figure 1 shows a color picture tube, which is one embodiment of the picture tube.
The figure shows the electron gun. This color picture tube has a panel (
1O) and a funnel (11) integrally joined to this panel (1o);
10) A phosphor screen (12) consisting of a three-color phosphor layer that emits blue, green, and red light is formed on the inner surface, and a large number of electron beams are placed inside the phosphor screen (12), facing A shadow mask (13) in which a passage hole is formed is arranged.

On the other hand, a cone (15) of the funnel (11) is provided with an anode terminal (16), and an internal conductive film (18) extends from the cone (15) to the inner surface of the area adjacent to the neck (17).
) is formed by coating. Also, inside the neck (17) are 3 electron beams (19B), (19G), (191?)
An electron gun (20) that emits .

This electron gun (20) has three cathodes (K) and three heaters (K) inserted inside each cathode (K).
(not shown) and first to sixth grids (G1) to (G6) sequentially arranged in the direction from the cathode (K) to the phosphor screen (12), which are connected to a pair of insulating supports (22). ) are fixed together. The cathode (K) side is connected to a stem pin (24) that airtightly passes through a stem (23) that seals the end of the neck (17).
), and the distal end side is supported by a plurality of valve spacers (25) attached to the sixth grid (G6) and in pressure contact with the internal conductive film (18).

Furthermore, in this color picture tube, the neck (1
A resistor (27) is attached to the back side of one of the insulating supports (22) along the electron gun (20) in the electron gun (7). This resistor (27) has a predetermined resistance pattern formed on an insulating substrate, and one end thereof is connected to the third grid (G3) via a predetermined stem pin (24).
The other end is connected to ground or a variable resistor via another predetermined stem pin (24).

By the way, the voltage to each electrode of the electron gun (18) is applied to the cathode (K), the heater, and the first to fifth grids (G1) to (G5) through a plurality of stem pins (24). Ru. For example, the cathode (K
) is connected via the stem pin (24) to a cut-off voltage of 150 µm and a voltage including the video signal, the first grid (G1) is grounded via the stem pin (24), and the second
50 to the grid (G2) via the stem pin (24).
A voltage of 0 v to 1 kV is applied to the third grid (G3), and a voltage of 8 to 9 kV is applied to the third grid (G3) via the stem pin (21). Further, a voltage of 1 to 2 kV is applied to the fourth grid (G4) through the resistor (27) as shown in FIG.
5 to the grid (G5) via the resistor (27).
A voltage of ~6 kV is applied. Also, the 6th grid (G6
) is connected to the anode terminal (16), the internal conductive film (18), and the valve spacer (25) in pressure contact with the anode terminal (16).
An anode high voltage of ~35 kV is applied.

By applying the above voltage, the electron gun (18) is connected to the cathode (K) and the first to third grids (Gl) to (G
3), the electron beam forming part (GEA) is formed by the third to sixth grids (G3) to (G6), and the main electron lens part (MLA) is formed by the third to sixth grids (G3) to (G6). ) forming the fourth and fifth grids (
When the voltage of about 8 to 9 kV applied to the third grid (G3) is divided by resistance and applied to G4) and (G5),
An electron gun with excellent performance can be obtained.

In other words, if the anode voltage Eb is resistance-divided by a resistor and applied to the third grid (G3) as in a conventional electron gun, when the anode high voltage is 32 kV, the power consumption W is Even if the resistance value R is 1000Ω, it becomes very large from W-Eb/R to approximately IW. However, like the electron gun in this example, the 8 to 9 kV applied to the third grid (G3)
When the voltage is divided by resistance and applied, the resistance value R becomes 100M.
Even if Ω, the power consumption W is only 0.64 to 0.81
W can be made very small.

Therefore, the design of the resistor becomes extremely easy and reliability is improved. Moreover, since the resistance value is small, it is easy to control the divided resistance value, it is possible to apply an accurate voltage divided by the resistance, and it is also easy to vary the divided voltage from the outside.

In the above embodiment, the case where the voltage applied to the third grid is resistance-divided and applied to the fourth and fifth grids has been explained. A predetermined voltage can be applied to the electron gun, and it can be easily applied to various types of electron guns other than the above embodiments.

[Effects of the Invention] As described above, a resistor is arranged along the electron gun, one end of the resistor is connected via a stem pin to an electrode to which a relatively high voltage is applied other than the anode electrode, If the structure is such that the relatively high voltage applied to this electrode is divided by resistance and a predetermined voltage is applied to the electrode to which a relatively low voltage is applied, the number of electrodes will be increased to improve the performance of the electron gun. However, the required voltage can be applied to each electrode via the stem pin, similar to an electron gun with a small number of electrodes, making it possible to create a highly practical cathode ray tube. In addition, since such a resistor divides a voltage lower than the anode high voltage by resistance, it does not need to have a high resistance unlike the conventional resistor which divides the anode high voltage by resistance, and the power consumption can be reduced. Resistor design becomes easier and reliability is improved. In addition, it becomes easy to control the divided resistance, and it is possible to accurately divide and apply the resistance. Furthermore, it has the effect of eliminating inconveniences in the cathode ray tube manufacturing process.

[Brief explanation of the drawing]

1 to 3 are detailed explanatory diagrams of the present invention, with FIG. 1 showing the configuration of a color picture tube as an embodiment thereof, FIG. 2 showing the configuration of its electron gun, and FIG. FIG. 3 is a diagram showing the connection configuration of resistors arranged along the electron gun, and FIG. 4 is a diagram showing the configuration of a conventional electron gun. DESCRIPTION OF SYMBOLS 10... Panel, 11... Funnel, 12... Phosphor screen, 16... Anode terminal, 18 Internal conductive film, 1.
9B, 19G, 191? ...3 electron beams, 20...
- Electron gun, 22... Insulating support, 2g-stem, 24... 3 pins on stem, 25 Valve spacer 27... Resistor, K... Cathode,
G1...first grid, G2...second grid,
G3...3rd grid, G4...4th grid, G5...5th grid, 1st grid, G6...6th grid
Grid.

Claims (1)

[Claims] An electron gun having a cathode and a plurality of electrodes for controlling, accelerating and focusing an electron beam from the cathode onto a target; and a neck end of an envelope in which the electron gun is arranged. a stem portion which is hermetically sealed and through which a plurality of stem pins for applying a predetermined voltage to the plurality of electrodes of the electron gun are hermetically penetrated; One end of the plurality of electrodes is connected to an electrode to which a relatively high voltage is applied, excluding the anode electrode, through the stem pin, and the voltage applied to this electrode is divided by resistance to obtain a relatively low voltage. A cathode ray tube comprising a resistor for applying a predetermined voltage to an electrode.