JP2002231153A - Cathode-ray tube device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cathode-ray tube device provided with an electron gun structure having favorable image characteristics and drive characteristics capable of restricting enlargement of a beam spot diameter on a phosphor screen even when current quantity of an electron beam is increased, and reducing drive voltage quantity for changing the current quantity of the electron beam. SOLUTION: An electron beam generating part to generate the electron beam is provided with a cathode K, a first grid G1, a second grid G2, and an auxiliary electrode GS disposed between the cathode and the first grid. The electron beam generating part composed of these electrodes satisfies relation of: applied voltage to the first grid < applied voltage to the auxiliary electrode < applied voltage to the cathode < applied voltage to the second grid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode ray tube device, and more particularly, to a cathode ray tube for applying a current to a cathode to suppress an increase in a beam spot diameter at a high current and to change a current amount of an electron beam emitted from the cathode. A cathode ray tube device comprising an electron gun assembly provided with a means for reducing a drive voltage.

[0002]

2. Description of the Related Art At present, a self-convergence in-line type color cathode ray tube device having an in-line type electron gun structure for emitting three electron beams arranged in a line has been widely put into practical use.

[0003] The triode portion, ie, the electron beam generating portion, of this electron gun assembly is composed of a cathode and a first electrode and a second electrode which are sequentially arranged at a predetermined distance from the cathode in the direction of the phosphor screen. Have been. A voltage for extracting electrons from the cathode is applied to the second electrode. Thus, the electric field generated by the potential difference between the second electrode and the first electrode permeates the cathode through the opening of the first electrode. This penetrating electric field causes electrons to be emitted from the cathode.

On the other hand, a voltage for controlling the amount of emitted electrons is applied to the cathode. When the applied voltage to the cathode is made lower than the cutoff voltage value, when the applied voltage is reduced between certain voltage values, electrons start to be emitted from the cathode due to the penetrating electric field. Further, by reducing the voltage applied to the cathode, the amount of electrons emitted from the cathode also increases. Thus, in general,
The electron beam generator of the electron gun assembly generates and controls an electron beam.

Here, when a high current is emitted from the cathode, the electron beam emission area of the cathode is large. At this time, as shown in FIG. 4, since the curvature of the electric field formed between the cathode K and the first electrode G1 is small, the electron beam emitted from the periphery of the electron emission region of the cathode K has the central axis. A passing position, a so-called crossover position A, is different from a crossover position B of the electron beam emitted from the center of the electron emission region of the cathode K. For this reason, the virtual object point diameter increases, and the beam spot diameter formed on the phosphor screen increases, deteriorating the image quality.

The difference between the cut-off voltage value applied to the cathode for suppressing the emission of electrons and the voltage applied when the voltage applied to the cathode for emitting an electron beam from the cathode is reduced is generally called a drive voltage. ing. When a drive voltage value for obtaining a necessary amount of electron beam current is large, a load on a signal circuit for providing the drive voltage increases. In recent years, the frequency of video signals has been further increased due to the increase in resolution of images, and the load on signal circuits has increased, resulting in deterioration of withstand voltage characteristics and increase in manufacturing costs.

According to Japanese Patent Application Laid-Open No. 54-14154,
A configuration for preventing deterioration of a spot at a high current is disclosed. That is, as shown in FIG. 5, the electron beam generator in the electron gun assembly includes a cathode K and a first electrode G1
And an electric field correction electrode Gc disposed between the two. The same voltage as that of the cathode K is applied to the electric field correction electrode Gc. The electric field correction electrode Gc is connected to the first electrode G
1 has an opening smaller than the opening diameter. The electric field correction electrode Gc reduces the curvature of the electric field formed between the cathode K and the first electrode G1 so that the cathode K
The difference between the crossover position of the electron beam emitted from the center of the upper electron emission region and the crossover position of the electron beam emitted from the periphery of the electron emission region is eliminated, and the virtual object point diameter is reduced to improve the quality. Is to obtain a simple beam spot.

However, in this method, since the aperture diameter of the electric field correction electrode Gc is smaller than the aperture diameter of the first electrode, the electron emission region is limited when generating a high current electron beam. The drive voltage value must be increased, which further increases the load on the signal circuit described above.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and suppresses an increase in the beam spot diameter on a phosphor screen even when the amount of current of an electron beam increases. And a cathode-ray tube device provided with an electron gun assembly having good image characteristics and drive characteristics, which is capable of reducing the drive voltage for changing the amount of current of the electron beam. The purpose is to do.

[0010]

According to a first aspect of the present invention, there is provided a cathode ray tube device for generating an electron beam, and an electron beam generating unit for generating an electron beam. The electron beam is accelerated toward the phosphor screen, and an electron lens unit having an electron lens unit for focusing on the phosphor screen.In a cathode ray tube device including an electron gun assembly, the electron beam generating unit includes a cathode and a cathode. A first electrode for limiting an emission area of the emitted electron beam, a second electrode to which a voltage for extracting the electron beam from the cathode is applied, and an auxiliary electrode disposed between the cathode and the first electrode And the first electrode, the auxiliary electrode, and the second electrode are arranged in this order along the traveling direction of the electron beam, and the electron beam of each electrode is arranged in this order. The holes are arranged so as to be located on the same straight line, and satisfy a relationship of applied voltage to the first electrode <applied voltage to the auxiliary electrode <applied voltage to the cathode <applied voltage to the second electrode. And

[0011] The cathode ray tube device according to claim 2 is
The auxiliary electrode has an electron beam passage hole having a diameter substantially equal to or larger than the electron beam passage hole of the first electrode.

According to the cathode ray tube device of the present invention, a voltage between the voltage applied to the first electrode and the voltage applied to the cathode is applied to the auxiliary electrode. The electron beam passage hole of the auxiliary electrode has a larger diameter than the electron beam passage hole of the first grid. Therefore, the penetrating electric field from the second electrode is spread radially around the tube axis due to the influence of the auxiliary electrode, and the curvature of the electric field becomes gentle.

Accordingly, the crossover position of the electron beam emitted from the periphery of the electron emission region of the cathode approaches the crossover position of the electron beam emitted from the center of the electron emission region of the cathode, and the virtual object diameter is reduced. It can be reduced. Therefore, the beam spot diameter formed on the phosphor screen can be reduced, and a good image can be displayed.

The penetrating electric field from the second electrode is spread radially around the tube axis under the influence of the auxiliary electrode, and as a result, the penetrating electric field is densely distributed along the tube axis direction. Becomes stronger. Thereby, the amount of current per unit area emitted from the cathode increases. Moreover, since the electron beam passage hole formed in the auxiliary electrode has a larger diameter than the electron beam passage hole of the first electrode, the electron emission region is not narrowed by the auxiliary electrode.

Therefore, it is possible to efficiently control electron emission from the cathode. Therefore, a high-current electron beam can be emitted from the cathode at a lower drive voltage, and the load on the signal circuit can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the cathode ray tube device of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a cathode ray tube device, that is, an in-line type color cathode ray tube device, comprises an enclosure comprising a panel 1, a neck 5, and a funnel-shaped funnel 2 for integrally joining the panel 1 and the neck 5. It has a vessel. The panel 1 has on its inner surface a phosphor screen 3 composed of a three-color phosphor layer in the form of dots or stripes that emit blue, green, and red light. The shadow mask 4 has a number of electron beam passage holes inside thereof, and is arranged to face the phosphor screen 3.

The neck 5 has an in-line type electron gun structure 7 disposed therein. This electron gun structure 7
Emits three electron beams 6B, 6G, 6R arranged in a line composed of a center beam 6G and a pair of side beams 6B, 6R passing on the same horizontal plane.

The deflection yoke 8 is mounted from the large diameter portion of the funnel 2 to the neck 5. This deflection yoke 8
Are three electron beams 6B and 6 emitted from the electron gun assembly 7.
A non-uniform deflection magnetic field that deflects G and 6R in the horizontal direction (X) and the vertical direction (Y) is generated. This non-uniform magnetic field is formed by a pincushion-type horizontal deflection magnetic field and a barrel-type vertical deflection magnetic field.

The three electron beams 6 B, 6 G, and 6 R emitted from the electron gun assembly 7 are deflected by the asymmetric magnetic field generated by the deflection yoke 8 and move the phosphor screen 3 through the shadow mask 4 in the horizontal direction X and the vertical direction. Scan in the direction Y. Thereby, a color image is displayed.

As shown in FIG. 2, the electron gun assembly 7 includes three cathodes K (R, R) arranged in a row in the horizontal direction (X).
G, B), three heaters for individually heating these cathodes K (R, G, B), and five electrodes. Five electrodes, namely, an auxiliary electrode GS, a first grid G1 for limiting the emission area of the electron beam, a second grid G2 to which a voltage for extracting an electron beam from the cathode is applied, a third grid (focus electrode) G3, And a fourth grid (anode electrode) G4 has a cathode K (R,
G and B) are sequentially arranged in the direction of the phosphor screen. The heater, the cathode K (R, G, B) and the five electrodes are integrally fixed by a pair of insulating supports.

The auxiliary electrode GS, the first grid G1, and the second grid G2 are each formed by a plate-like electrode having an integral structure. These plate-like electrodes have three relatively small, substantially circular electron beam passage holes formed in a row in the horizontal direction X corresponding to the three cathodes K (R, G, B). In particular, the electron beam passage hole formed in the auxiliary electrode GS has a slightly larger hole diameter than the electron beam passage hole formed in the first grid G1. These auxiliary electrode GS, first grid G1, and second grid G2
Are arranged such that the electron beam passage holes formed respectively are located on the same straight line.

The third grid G3 is constituted by a cylindrical electrode having an integral structure. The cylindrical electrodes are arranged in a row in the horizontal direction X corresponding to the three cathodes K (R, G, B) on both end surfaces thereof, that is, a surface facing the second grid G2 and a surface facing the additional electrode Gs. Have three substantially circular electron beam passage holes. The electron beam passage hole formed on the surface of the third grid G3 facing the second grid G2 has a larger diameter than the electron beam passage hole formed on the second grid G2. Also, the third grid G
The third electron beam passing hole formed on the surface facing the fourth grid G4 has a larger diameter than the electron beam passing hole formed on the surface facing the second grid G2.

The fourth grid G4 is constituted by a cylindrical electrode having an integral structure. The cylindrical electrode is formed in a row in the horizontal direction corresponding to the three cathodes K (R, G, B) on both end surfaces thereof, that is, a surface facing the additional electrode Gs and an end surface on the phosphor screen side. And three substantially circular electron beam passage holes. The electron beam passage hole formed in the fourth grid G4 has a larger hole diameter than the electron beam passage hole formed in the surface of the third grid G3 facing the second grid G2.

In the electron gun assembly 7 having the above-described configuration, the cathode K (R, G, B) is connected to the electron gun power source 37 to 10
A voltage obtained by superimposing a video signal on a DC voltage of 0 to 200 V is applied. The first grid G1 is grounded. An intermediate voltage higher than the voltage applied to the first grid G1 and lower than the voltage applied to the cathode K (R, G, B) is applied to the auxiliary electrode GS. For example, the auxiliary electrode GS
, A voltage of about 10 to 100 V is applied from the electron gun power supply 38.

The cathodes K (R, R,
A voltage higher than the voltage applied to G, B) is applied. For example, a cut-off voltage of 500 to 1000 V is applied to the second grid G2 from the electron gun power supply 36 via a stem pin (not shown) that hermetically penetrates a stem (not shown).

The third grid G3 has a fourth grid G4
Is supplied as a reference voltage, for example, a DC voltage of about 6 kV, which is about 20 to 35% of the anode voltage applied.
An anode voltage Eb of 25 to 35 kV is applied to the fourth grid G4 from the high voltage power supply 35 via an anode terminal 30 provided in the funnel 2.

The electron gun assembly 7 applies the above-described voltage to each grid, thereby causing the electron beam generating section G
E, a prefocus lens PL, and a main lens ML are formed. The electron beam generator GE is formed by the cathode K, the auxiliary electrode GS, the first grid G1, and the second grid G2. The electron beam generator GE controls electron emission from the cathode K (R, G, B) and accelerates and focuses the emitted electrons to form an electron beam. The electron beam generator GE forms an object point with respect to the main lens.

The prefocus lens PL is formed by the second grid G2 and the third grid G3. This prefocus lens PL preliminarily focuses the electron beam generated from the electron beam generator GE.

The main lens ML includes a third grid G3 (focus electrode) and a fourth grid G4 (anode electrode).
Formed by The main lens ML finally focuses the electron beam prefocused by the prefocus lens PL on the phosphor screen.

Here, the operation of the electron beam generator GE will be described in more detail.

First, in the cut-off state, the cathode K is applied to the auxiliary electrode GS having an electron beam passage hole having a diameter slightly larger than the electron beam passage hole of the first grid G1.
A voltage intermediate between the voltages applied to (R, G, B) and the first grid G1 is applied. Therefore, the penetrating electric field penetrating the cathode K (R, G, B) from the second grid G2 through the electron beam passage hole of the first grid G1, is pulled by the auxiliary electrode GS as shown in FIG. And radially expanded about the tube axis Z. As a result, the penetrating electric field is densely distributed along the tube axis Z direction, and a stronger electric field intensity can be obtained than when the auxiliary electrode GS is not provided.

When the electron beam is emitted, as shown in FIG. 3, the curvature of the electric field radially expanded around the tube axis is smaller than that in the case where the auxiliary electrode is not provided, that is, the curvature becomes larger. , Cathode K (R, G,
B), the position of the electron beam emitted from the periphery of the electron emission region passing through the center axis Z approaches the center of the electron beam emitted from the center of the electron emission region of the cathode.

That is, the crossover position on the central axis Z of the electron beam emitted from the periphery of the electron emission region approaches the crossover position on the central axis Z of the electron beam emitted from the center of the electron emission region. As described above, the aberration received by the electron beam between the cathode K (R, G, B) and the first grid G1 can be reduced, so that a smaller virtual object point can be formed. Further, a smaller beam spot can be formed on the phosphor screen 3, and good image characteristics can be obtained.

The electric field strength of the penetrating electric field along the tube axis Z direction is higher than that without the auxiliary electrode GS. Therefore, when a drive voltage for emitting electrons from the cathode K (R, G, B) is applied to the cathode K to generate an electron beam from the cathode K,
Since the electron beam emission amount per unit area in the electron beam emission region is increasing and the electron beam passage hole of the correction electrode GS has a larger hole diameter than the electron beam passage hole of the first grid G1, The electrode GS does not narrow the electron emission region. Therefore, the cathode K (R, G,
B) makes it possible to emit a high-current electron beam.

Next, the configuration of another electron gun structure applied to the cathode ray tube device of the present invention will be described. This electron gun structure is basically the same as the structure of the electron gun structure of the above-described embodiment as shown in FIG. The electron beam generator GE has a structure as shown in FIG.

That is, the cathode K and the second grid G2
And an insulating plate-like member GH is disposed between them.
This plate-shaped member GH has three cathodes K (R, G, B).
, Three relatively small electron beam passage holes formed in a row in the horizontal direction X. These electron beam passage holes have the second grid G on the cathode K side.
It is formed in a tapered shape that is larger than the two sides.

The surface of the plate member GH on the cathode K side and the second
A metal film formed by sputtering or the like is provided on the surface on the grid G2 side except for the electron beam passage holes. The metal film arranged on the cathode K side of the plate member GH functions as an auxiliary electrode GS. Further, the plate-shaped member G
The metal film arranged on the second grid G2 side of H functions as the first grid G1.

The plate-like member GH having the auxiliary electrode GS and the first grid G1 is arranged such that the electron beam passage holes formed respectively are positioned on the same straight line with respect to the second grid G2.

The first grid G1 is grounded. An intermediate voltage higher than the voltage applied to the first grid G1 and lower than the voltage applied to the cathode K (R, G, B) is applied to the auxiliary electrode GS. For example, the auxiliary electrode GS
, A voltage of about 10 to 100 V is applied from the electron gun power supply 38.

The same effect as that of the above-described embodiment can be obtained also in the electron gun structure configured as described above. In addition, it is possible to easily arrange the auxiliary electrode and the first grid in a narrow space between the cathode K and the second grid G2.

In the above-described embodiment, the main lens ML has an axisymmetric BPF (Bi-Potential F).
Although the present invention has been described with respect to an electron gun assembly for an Ocus) type color cathode ray tube device, the present invention is not limited to the electron gun assembly having this structure, but includes a three-pole unit for generating and controlling an electron beam. It goes without saying that the present invention can be applied to other cathode ray tube devices having the provided electron gun structure.

As described above, the electron gun assembly applied to the color cathode ray tube device of the present invention has an electron beam generating section for generating an electron beam. The electron beam generator includes a cathode, a first grid for limiting an emission area of an electron beam emitted from the cathode, a second grid to which a voltage for extracting an electron beam from the cathode is applied, a cathode and a first grid. And an auxiliary electrode disposed between the grid and the grid. The electron beam generator constituted by these electrodes satisfies the relationship: applied voltage to first grid <applied voltage to auxiliary electrode <applied voltage to cathode <applied voltage to second grid.

The auxiliary electrode has an electron beam passage hole having a diameter substantially equal to or larger than the electron beam passage hole of the first grid.

Therefore, the penetrating electric field from the second grid is spread radially around the tube axis under the influence of the auxiliary electrode, and the curvature of the electric field becomes gentle. Thereby, the crossover position of the electron beam emitted from the periphery of the electron emission region of the cathode approaches the crossover position of the electron beam emitted from the center of the electron emission region of the cathode, and the virtual object diameter is reduced. Becomes possible. Therefore, the beam spot diameter formed on the phosphor screen can be reduced, and a good image can be displayed.

The penetrating electric field from the second grid is spread radially around the tube axis under the influence of the auxiliary electrode, and as a result, the penetrating electric field is densely distributed along the tube axis direction. Becomes stronger. Thereby, the amount of current per unit area emitted from the cathode increases. In addition, the electron beam passage hole formed in the auxiliary electrode is
Since the grid G1 has a larger hole diameter than the electron beam passage hole, the electron emission region is not narrowed by the auxiliary electrode.

Therefore, it is possible to efficiently control the electron emission from the cathode. Therefore, a high-current electron beam can be emitted from the cathode at a lower drive voltage, and the load on the signal circuit can be reduced.

[0048]

As described above, according to the present invention, it is possible to suppress an increase in the beam spot diameter on the phosphor screen even if the amount of current of the electron beam is increased, and to suppress the electron beam. The amount of drive voltage for changing the amount of current can be reduced, and a cathode ray tube device having an electron gun assembly having good image characteristics and drive characteristics can be provided.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view schematically showing a structure of a color cathode ray tube device according to one embodiment of the present invention.

FIG. 2 is a horizontal sectional view schematically showing a structure of an electron gun assembly applied to the color cathode ray tube device shown in FIG.

3 is a horizontal and vertical cross-sectional view showing a structure of an electron beam generating unit in the electron gun assembly shown in FIG. 2 and a relationship between a penetrating electric field and an electron beam orbit in the electron beam generating unit.

FIG. 4 is a horizontal and vertical cross-sectional view showing a structure of an electron beam generator in a conventional electron gun assembly and a relationship between a penetrating electric field and an electron beam orbit in the electron beam generator.

FIG. 5 is a vertical cross-sectional view showing a structure of an electron beam generator in a conventional electron gun assembly.

6 is a horizontal and vertical cross-sectional view showing the structure of another electron beam generator in the electron gun assembly shown in FIG. 2 and the relationship between the penetrating electric field and the electron beam orbit in the electron beam generator.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Panel 2 ... Funnel 3 ... Phosphor screen 4 ... Shadow mask 5 ... Neck 6 (R, G, B) ... Electron beam 7 ... Electron gun structure K (R, G, B) ... Cathode GS ... Auxiliary electrode G1 ... 1st grid G2 ... 2nd grid G3 ... 3rd grid G4 ... 4th grid GH ... plate-shaped member

Claims (3)

[Claims] An electron beam generating section for generating an electron beam, and an electron lens section for accelerating an electron beam generated from the electron beam generating section toward a phosphor screen and converging the electron beam on the phosphor screen. In a cathode ray tube device having an electron gun assembly, the electron beam generator includes a cathode, a first electrode for limiting an emission region of an electron beam emitted from the cathode,
A second electrode to which a voltage for extracting an electron beam from the cathode is applied, and an auxiliary electrode disposed between the cathode and the first electrode; the first electrode and the auxiliary electrode The second electrodes are arranged in this order along the traveling direction of the electron beam, and the second electrodes are arranged such that the electron beam passage holes of the respective electrodes are located on the same straight line, and the voltage applied to the first electrode < A cathode ray tube device, which satisfies a relationship of: applied voltage to an auxiliary electrode <applied voltage to a cathode <applied voltage to a second electrode. 2. The cathode ray tube according to claim 1, wherein said auxiliary electrode has an electron beam passage hole having a diameter substantially equal to or larger than an electron beam passage hole of said first electrode. apparatus. 3. The device according to claim 1, wherein the auxiliary electrode and the first electrode are formed of a metal film integrally provided on the cathode side and the second electrode side of a plate-shaped insulator. A cathode ray tube device according to item 1.