JPH11149885A - Electron gun for color cathode-ray tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-line 3 beams type color cathode-ray tube that can as possible as uniformly possible shape of three electron beams at right and left ends part of a phosphor surface. SOLUTION: This color cathode-ray tube electron gun 10 has focusing electrode 51 (51A, 51B, 51C) divided into a half or more. For the divided focusing electrode 51, one of holes, in which outer electron beams R, B among the three electron beams pass through, is of a large diameter and the other one is small diameter at the opposing divided focusing electrodes. Inside the same divided focusing electrodes, the hole in which one of the outer electron beams passes is a large diameter, and the hole in which the other one of the outer electron beams is small in diameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an in-line three-beam type electron gun for a color cathode ray tube used for a color cathode ray tube constituting a color picture tube or a color display device, for example.

[0002]

2. Description of the Related Art At present, the demand for resolution of a color cathode ray tube is increasing more and more, and in particular, a problem concerning a spot shape of an electron beam around a screen is attracting attention.

In general, the resolution characteristics of a color cathode ray tube largely depend on the size and shape of an electron beam spot on a phosphor screen serving as a screen. That is, unless the spot diameter of the electron beam is small and close to a perfect circle, good resolution characteristics cannot be obtained.

As the deflection angle of the electron beam increases, the trajectory of the electron beam from the electron gun for the cathode ray tube to the phosphor screen becomes longer. For this reason, if the focus voltage is maintained so as to obtain an electron beam spot with a small diameter and a perfect circle at the center of the phosphor screen, the periphery of the phosphor screen will be in an overfocus state. As a result, an electron beam spot having a small diameter and a perfect circle cannot be obtained in the peripheral portion of the phosphor screen, and good resolution cannot be obtained.

Therefore, in recent years, as the deflection angle of the electron beam increases, the focus voltage of the electron beam colliding with the peripheral portion of the phosphor screen is increased to weaken the function of the main lens. Guns have been proposed. However, this dynamic focus method is not suitable for an in-line three-beam type electron gun for a cathode ray tube as it is. That is,
In a conventional cathode ray tube electron gun of an in-line three-beam type in which three cathodes are arranged in a horizontal straight line, when the deflection magnetic field of the deflection yoke is equal, the vertical and horizontal peripheral portions of the fluorescent screen are vertical. An arcuate convergence error (overconvergence) occurs.

Therefore, conventionally, dynamic convergence is performed by setting the horizontal deflection magnetic field distribution by the deflection yoke to a pincushion shape and the vertical deflection magnetic field distribution to a barrel shape.

However, when the deflection yoke having such a structure is used, the electron beam passing through the deflection yoke and deflected toward the peripheral portion of the phosphor screen converges in its vertical direction (vertical direction). (Convex lens effect) and a diverging effect (concave lens effect) in the horizontal direction (lateral direction). As a result, the electron beam spot at the peripheral portion of the phosphor screen does not have a perfect circle but has a horizontally long shape. Therefore, at the left and right peripheral portions of the phosphor screen, there are problems that the electron beam spot is distorted and the focus characteristic is deteriorated.

In order to solve such a problem, a so-called electrostatic quadrupole lens (hereinafter simply referred to as a quadrupole lens) is used.
An electron gun for a cathode ray tube incorporating a
Japanese Patent Application Laid-Open No. 99249/99, Japanese Patent Application Laid-Open No. 62-237642, and Japanese Patent Application Laid-Open No. 3-93135.

FIG. 18 is a schematic diagram showing the configuration of a generally used electron gun for a color cathode ray tube incorporating a quadrupole lens. The electron gun 70 has three cathodes K _R , K _G , and K _B arranged in line in parallel.
_{(K R, K G, K} B) toward and from the anode side, the first electrode 11, second electrode 12, third electrode 13, fourth electrode 14, fifth electrode, the sixth electrode 16, the shield cup 17 They are sequentially arranged coaxially. The fifth electrode is divided into two, a 5-1st electrode 51 and a 5-2nd electrode 52. The second electrode 12 and the fourth electrode 14 are electrically connected.

In the electron gun 70 for a color cathode ray tube, a constant first focus voltage Ef1 is applied to the third electrode 13 and the 5-1st electrode 51 via the stem. On the other hand, a second focus voltage Ef2 in which a parabolic waveform voltage synchronized with horizontal deflection is superimposed on the first focus voltage Ef1 is applied to the 5-2 electrode 52. Thus, the 5-1 electrode 51 and the 5-2 electrode 52
And a quadrupole lens (not shown) is formed between the lens and the focus lens (not shown) formed between the 5-2 electrode 52 and the sixth electrode 16. Causes a change in intensity. As a result, it is possible to improve the shape of the electron beam in the peripheral portion of the phosphor screen in the left-right direction.

By providing the quadrupole lens as described above, as the electron beam approaches the horizontal end of the phosphor screen, the electron beam undergoes a diverging action (concave lens effect) in its vertical direction (vertical direction). On the other hand, it is converged in the horizontal direction (lateral direction) (convex lens effect). as a result,
The electron beam spot at the periphery of the phosphor screen approaches a perfect circle, and as a result, a good resolution can be obtained.

The effect of providing the quadrupole lens in this way is significant. This method of simultaneously operating the quadrupole lens and the dynamic focus voltage is widely used in displays, large-sized TVs, and electron guns for color cathode ray tubes for high-definition TVs.

[0013]

In the above-mentioned known prior art, the same amount of quadrupole effect and convergence are given to the three electron beams R, G and B. Accordingly, as shown in FIG. 19, a schematic diagram of the cathode ray tube,
The three electron beams R, G, and B emitted from the screen and colliding with the peripheral portions of the screen on the right side and the left side of the screen of the phosphor screen 4 differ in the degree of the focusing action and the diverging action received in the magnetic field of the deflection yoke 2. . Therefore, the state of distortion of the electron beam spot at the left and right peripheral portions of the fluorescent screen 4 differs for the three electron beams R, G, and B. In the figure, reference numeral 3 denotes a glass bulb. In addition, “the right side of the screen” and “the left side of the screen” respectively mean the right side and the left side when the fluorescent screen 4 of the color cathode ray tube is observed from the outside.

Usually, the focus voltage and the like are set so that the spot shape of the central electron beam G among the three electron beams R, G, and B is optimal. In this case, when three electron beams R, G, and B collide with the right side of the fluorescent screen 4, the electron beam R is more affected by the deflection magnetic field formed by the deflection yoke 2 than the electron beams G and B. Receive strongly. As a result, the distortion of the beam spot of the electron beam R on the phosphor screen 4 becomes larger than the other electron beams G and B. On the other hand, when three electron beams R, G, and B collide with the left side of the phosphor screen 4, the electron beam B
Are more strongly affected by the deflection magnetic field formed by the deflection yoke 2 than the electron beams G and R. As a result, the distortion of the beam spot of the electron beam B on the phosphor screen 4 becomes larger than the other electron beams R and G.

That is, the spots located at the innermost of the three spots corresponding to the respective electron beams, that is, the spot of the electron beam R on the right side of the screen and the spot of the electron beam B on the left side of the screen are particularly deteriorated in shape.

Accordingly, in a recent large-sized color display monitor having a high resolution, due to such a phenomenon, red characters are blurred on the right side of the phosphor screen 4 and blue characters are blurred on the left side of the phosphor screen 4. May be unclear.

Therefore, as one means for solving such a problem, a (red) electron beam R irradiating the red phosphor and a (blue) electron beam B irradiating the blue phosphor are respectively An electron gun giving quadruple lens effects with different intensities was proposed earlier.

However, in the above-described electron gun, the red electron beam R and the blue electron beam B can be provided with quadrupole lens effects having different intensities, but cannot be provided with converging effects having different intensities. Therefore, it is impossible to completely correct the difference between the focus voltages among the three electron beams R, G, and B.

In order to solve the above-mentioned problem, the present invention provides an in-line three-beam type electron beam for a color cathode ray tube which can make the beam spot shapes of three electron beams at the left and right ends of the phosphor screen as uniform as possible. Offers a gun.

[0020]

According to the first aspect of the present invention, there is provided a color cathode ray tube electron gun having a focus electrode divided into two or more parts.
Of the three electron beams, the size of the hole through which the outer electron beam passes is such that one of the opposed divided focus electrodes has a large diameter and the other has a small diameter. The hole through which one outer electron beam passes has a large diameter, and the hole through which the other outer electron beam passes has a small diameter.

The second electron gun for a color cathode ray tube according to the present invention has a focus electrode divided into two or more, and the outer one of the three electron beams passes through the divided focus electrode. The thickness of the electrode around the hole to be formed is such that one of the opposing divided focus electrodes is formed thicker and the other is formed thinner, and within the same divided focus electrode, one outer electron beam passes. The perimeter of the hole is thick, and the perimeter of the hole through which the other outer electron beam passes is formed thin.

According to the first configuration of the present invention described above, the size of the hole through which the outer one of the three electron beams passes is one of the divided focus electrodes facing each other, one of which has a large diameter. The other has a small diameter, and within the same divided focus electrode, the hole through which one outer electron beam passes has a large diameter, and the hole through which the other outer electron beam passes has a small diameter. Thereby, lens effects having different intensities can be given to the two outer electron beams.

According to the above-described second configuration of the present invention, the thickness of the electrode around the hole through which the outer one of the three electron beams passes is one of the divided focus electrodes facing each other. In the same divided focus electrode, the periphery of the hole through which the electron beam passes on one side is thick, and the periphery of the hole through which the electron beam on the other side passes is thin. By being
The two outer electron beams can be given lens effects with different intensities.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has a focus electrode divided into two or more parts. In the divided focus electrodes, the size of a hole through which the outer one of three electron beams passes is reduced. One of the opposed divided focus electrodes has a large diameter and the other has a small diameter. In the same divided focus electrode, the hole through which the electron beam on one side passes has a large diameter and the other outside has the large diameter. Is an electron gun for a color cathode ray tube having a small aperture through which the electron beam passes.

According to the present invention, in the electron gun for a color cathode ray tube, a fixed focus voltage is applied as a first focus voltage, and a parabolic waveform voltage synchronized with horizontal deflection to the fixed focus voltage is applied as a second focus voltage. A configuration is adopted in which a superimposed voltage is applied and a voltage in which a waveform voltage similar to a sawtooth wave synchronized with horizontal deflection is superimposed on a fixed focus voltage as a third focus voltage.

According to the present invention, in the above-mentioned electron gun for a color cathode ray tube, in the divided focus electrodes, one of the opposing electrodes has a first focus voltage and the other has a third focus voltage.
Is applied.

According to the present invention, in the electron gun for a color cathode ray tube, the first focus voltage is supplied through a resistor dividing the anode voltage, and the second and third focus voltages are supplied directly from the stem. Configuration.

The present invention has a focus electrode divided into two or more parts.
Of the three electron beams, the thickness of the electrode around the hole through which the outer electron beam passes is formed such that one of the divided focus electrodes facing each other is thicker and the other is thinner. This is an electron gun for a color cathode ray tube in which the outer periphery of a hole through which one outer electron beam passes is formed thicker and the outer periphery of the other outer hole through which an electron beam passes is formed thinner.

According to the present invention, in the above-mentioned electron gun for a color cathode ray tube, a fixed focus voltage is applied as a first focus voltage, and a parabolic waveform voltage synchronized with horizontal deflection to the fixed focus voltage is applied as a second focus voltage. A configuration is adopted in which a superimposed voltage is applied and a voltage in which a waveform voltage similar to a sawtooth wave synchronized with horizontal deflection is superimposed on a fixed focus voltage as a third focus voltage.

According to the present invention, in the above-mentioned electron gun for a color cathode ray tube, in the divided focus electrodes, one of the opposing electrodes has a first focus voltage and the other has a third focus voltage.
Is applied.

According to the present invention, in the above-mentioned electron gun for a color cathode ray tube, the first focus voltage is supplied through a resistor dividing the anode voltage, and the second and third focus voltages are supplied directly from the stem. Configuration.

An embodiment of an electron gun for a color cathode ray tube according to the present invention will be described below with reference to the drawings.

The electron gun for a color cathode ray tube according to the present embodiment has a focus electrode divided into three parts, and the focus electrode divided into three parts has a hole through which the outer one of the three electron beams passes. The size is such that one of the opposed divided focus electrodes has a large diameter and the other has a small diameter, and within the same divided focus electrode, a hole through which one outer electron beam passes has a large diameter. The case where the other outer hole through which the electron beam passes has a small diameter is shown.

FIG. 1 shows the arrangement of electrodes of the electron gun for a color cathode ray tube according to the present embodiment. This electron gun 10 has three cathodes K _R , K _G , and K _B arranged in parallel in a line.
From the cathode K (K _R , K _G , K _B ) toward the anode, the first electrode 11, the second electrode 12, the third electrode 13, and the fourth electrode
Electrode 14, fifth electrode, sixth electrode 16, shield cup 1
7 are sequentially arranged coaxially. The second electrode 12 and the fourth electrode are electrically connected to conduct.

The fifth electrode corresponding to the focus electrode is divided into two, a 5-1 electrode 51 and a 5-2 electrode 52. Further, the 5-1st electrode 51 is the 5-1st electrode.
An A electrode 51A, a 5-1B electrode 51B, and a 5-1C electrode 51C are divided into three. Therefore, the focus electrode (fifth electrode) is divided into four, and the 5-1A electrode 51
A, the 5-1B electrode 51B and the 5-1C electrode 51C form a first quadrupole lens, and the 5-1C electrode 51C and the 5-2 electrode 52 form a second quadrupole lens. It is formed. The operation of the quadrupole lens of the second quadrupole lens is controlled by the first quadrupole lens.

A voltage of, for example, 0 V (or several tens of V) is applied to the first electrode 11, and a voltage of, for example, 200 to 800 V is applied to the second electrode 12 and the fourth electrode 14. An anode voltage of, for example, 22 kV to 30 kV is applied to the electrode 16.

A fixed focus voltage (for example, 5 to 7 kV) is applied to the third electrode 13 and the 5-1A electrode 51A and the 5-1C electrode 51C on both outer sides of the divided 5-1 electrode 51. 1 focus voltage) Ef1 is applied. The fixed focus voltage E is applied to the 5-1B electrode 51B.
A third focus voltage Ef3 in which a waveform voltage (see FIG. 2) having a shape similar to a saw blade synchronized with the horizontal deflection of f1 and a fixed focus voltage Ef1 are superimposed is applied. Also,
A second focus voltage Ef2 in which a parabolic waveform voltage (see FIG. 2) synchronized with the horizontal deflection of the fixed focus voltage Ef1 and the fixed focus voltage Ef1 are superimposed is applied to the 5-2nd electrode 52. These three focus voltages Ef1, Ef2, Ef3 are normally supplied from the stem portion at the tip of the electron gun 10.

Here, although not shown, a divided resistor is arranged on the side of the electron gun 10, the anode voltage is divided by the divided resistor to supply a fixed focus voltage Ef1, and the remaining two focus voltages are supplied. A configuration in which Ef2 and Ef3 are supplied from the stem unit may be adopted. In this case, the number of focus voltages supplied from outside through the stem portion can be reduced.

Further, the 5-1A electrode 51A, the 5-1A
Each of the B electrode 51B and the 5-1C-th electrode 51C has 3
Two electron beam passage holes are provided. FIG. 3 is a schematic view showing an example of the shape of the electron beam passage hole of each of the 5-1 electrodes 51A, 51B, and 51C. FIG. 4A is a cross-sectional view of the 5-1 electrode 51 (51A, 51B, 51C) divided into three sections taken along a horizontal plane, and FIG. 4B shows the arrangement of through holes corresponding to three electron beams. Is shown in a schematic perspective view. FIGS. 3 and 4 show a case where a cylindrical shielding body 26 is provided in the central passage hole through which the electron beam G passes.

In the present embodiment, the passage holes for the electron beams on both sides are formed in a large-diameter circular shape or a small-diameter circular shape. Then, as shown in FIG. 3 and FIG. 4, the electron beam passing holes 21A, 2A provided on one end side on the opposing surfaces of the respective 5-1 electrodes 51A, 51B, 51C.
1B and 21C (in this embodiment, the electron beam R passes) are provided at electron beam passing holes 23A and 23A provided at the other end.
23B and 23C (in this embodiment, the electron beam B passes), the size of the aperture of the electron beam passage hole is reversed. Further, each of the 5-1 electrodes 51A, 51B, 51
The diameters of the electron beam passage holes provided on both end sides of C are opposite to those of the electron beam passage holes provided on the surface of the 5-1 electrode facing each other, and one of them is large. The caliber, the other is small.

More specifically, the electron beam passing holes 21A and 23A provided on both ends of the 5-1A electrode 51A are respectively provided with the electron beam passing holes 21B and 21B provided on both sides of the opposing 5-1B electrode 51B. The size of the caliber is opposite to that of 23B,
The electron beam passage holes 21B and 23B provided at both ends of the 5-1B electrode portion 51B are connected to the facing 5-1C electrode 5B.
Electron beam passage holes 21C and 2C provided at both ends of 1C
3C has a configuration in which the diameter is reversed.

That is, the electron beam passage holes 21A and 21C provided at one end side of the outer 5-1A electrode 51A and the 5-1C electrode 51C (the electron beam R in this embodiment).
Pass) is a large-diameter circular shape, and the electron beam passage holes 22A and 22C provided in the center (through which the electron beam G passes) are a medium-diameter circular shape, and the electron beam provided at the other end is provided. The beam passage holes 23A and 23C (in this embodiment, the electron beam B passes) have a small-diameter circular shape. On the other hand, the electron beam passage hole 21B (in this embodiment, the electron beam R passes) provided on one end side of the center 5-1B electrode 51B has a small diameter circular shape,
An electron beam passage hole 22B provided in the center (through which the electron beam G passes in the present embodiment) has a medium-diameter circular shape, and an electron beam passage hole 23B provided in the other end side (in this embodiment, The electron beam B passes) is a large-diameter circular shape.

In the case of FIGS. 3 and 4, this gives
The red electron beam R passing relatively outside the deflection magnetic field on the right side of the screen passes through the large-diameter, small-diameter, and large-diameter electron beam passage holes.
The converging lens effect is generated in the quadrupole lens of the electrode 51, and the converging lens effect which conventionally works is strengthened. Conversely, the blue electron beam B passing relatively inside the deflecting magnetic field on the right side of the screen passes through the small-, large-, and small-diameter electron beam passage holes. The diverging lens effect is generated in the quadrupole lens 51, and the converging lens effect which conventionally works is weakened.

At this time, the central green electron beam G is
The 5-1B electrode 5 at the center of the divided 5-1 electrode 51
The 1B electron beam passage hole 22B is the 5-1C electrode 51C.
Is shielded by the shielding body 26 protruding from the third focus voltage Ef3 having a sawtooth-like shape applied to the 5-1B-th electrode 51B.

Even when the shield 26 is not provided, the center green electron beam G can be prevented from being affected by the third focus voltage Ef3 in the following manner. (1) By making the difference between the diameters of the electron beam passage holes on both sides sufficiently large, or by setting the diameters of the electron beams R and B on both sides large, the amplitude of the waveform voltage Ef3 is suppressed small, and the green color on the left and right sides of the screen is obtained. The difference in the focus voltage of the electron beam G can be suppressed.
(2) The effect of the waveform voltage Ef3 on the green electron beam G can be reduced by increasing the center electron beam passage hole or setting the diameter of the center electron beam G small. In addition, the above-mentioned means (1) and (2) can be adopted simultaneously.

As described above, the difference between the convergence of the electron beams due to the deflecting magnetic field received by the electron beams R and B on both outer sides is canceled, and the three electron beams R, G and B are canceled.
Have the same good shape. The operation on the left side of the screen is the reverse of the above-described operation on the right side of the screen.

In the example described above, the electron beams R and B on both sides are formed by the focus electrode (the 5-1st electrode 51) divided into three.
Is the case where one receives the convergent lens effect and the other receives the divergent lens effect.

Not only in such a case, but also when both electron beams receive the convergent lens effect or both the electron beams receive the divergent lens effect, the electron beams R,
By providing a difference in the lens strength affecting B, the effect of the present invention can be obtained similarly. For example, when the electron beams R and B on both sides receive the convergent lens effect,
The intensity of the main lenses of the electron beams R and B on both sides may be set in advance to be lower than the intensity of the main lens of the central electron beam G. In the case where both lenses receive the divergent lens effect, the opposite may be performed.

As another embodiment of the present invention, an electron gun for a color cathode ray tube configured to give a quadrupole lens effect having different intensities to the red electron beam R and the blue electron beam B proposed above. It can also be applied to FIG.
FIG. 3 is a schematic diagram showing an example of the shape of the electron beam passage hole of each of the 5-1st electrodes 51A, 51B, and 51C in this case. In FIG. 5, each of the electron beam passage holes on both outer sides has a vertically long or horizontally long rectangular shape, and the directions of the long side and the short side are reversed. The vertical rectangular electron beam passage holes and the horizontal electron beam passage holes have different sizes and areas, and the vertical rectangular electron beam passage holes are smaller and smaller in area.

Thus, in addition to the effect of arranging the large-diameter circular or small-diameter circular electron beam passage holes in the above embodiment, the electron beam passage holes have a rectangular shape with a non-point shape. Therefore, a quadrupole lens effect can be provided.

In the above embodiment, the 5-1 electrode 51 is divided into three parts. However, in the configuration of the conventional electron gun 70 shown in FIG. 18, the third electrode 13, the 5-1 electrode 51, and the 5-
The present invention can be applied by dividing at least one of the two electrodes 52 and the sixth electrode 16 into three.

Here, another example of the third focus voltage Ef3 is shown in FIGS. 6A and 6B. FIG. 6A shows the case of a waveform that changes linearly in a shape similar to a sawtooth. FIG. 6B
Is a voltage in which a sinusoidal waveform generated intermittently once per horizontal deflection period is superimposed on the fixed focus voltage Ef1.

Originally, the waveform shown in FIG. 2 is desirable. However, the waveform shown in FIG. 6A can provide a sufficient effect, and the deterioration of focus is particularly severe at the outermost periphery of the screen. The waveform of FIG. 6B is also effective.

In addition, in the electrode configuration of FIG.
Electron beam passage holes 21B and 23 on both sides of B electrode 51B
The diameter of B may be the same. In the electrode configuration of FIG. 5, the electron beam passage holes 2 on both sides of the 5-1B electrode 51B are provided.
The rectangles 1B and 23B may have the same size.

As shown in FIG. 7, the present invention can be applied to an electron gun having two electrodes to which a parabolic second focus voltage Ef2 is applied. In this electron gun 20, the fourth electrode 14 is
The first electrode 41 and the 4-2nd electrode 42 are divided into two,
A fixed focus voltage Ef1 is applied to the 4-1st electrode 41, and a second focus voltage Ef2 in which a parabolic waveform voltage synchronized with horizontal deflection is superimposed on the fixed focus voltage Ef1 is applied to the 4-2nd electrode 42. Applied. Other configurations are the same as those of the electron gun 10 shown in FIG.

Further, the focus electrode is not divided into three parts, but two parts.
Even in the case of division, the same effect can be obtained.
FIG. 8 shows an electrode configuration of an embodiment of the electron gun in that case. In this electron gun 30, the sixth electrode 16 is divided into two parts,
The 6-1 electrode 61 and the 6-2 electrode 62 are electrically connected to the 6-1 electrode 61 and the shield cup 17 so that conduction is established. 3 focus voltage Ef3 is applied. Other configurations are the same as those of the electron gun 70 shown in FIG.

FIGS. 9A and 9B are plan views of the sixth electrode 16 (61, 62) at this time, and FIG. 9C is a cross-sectional view in a horizontal plane. From FIG. 9, the center electron beam G
The electron beam passing holes 22D and 22E through which the electron beams pass have the same diameter, and the electron beam passing holes through which the electron beams R and B on both sides pass are respectively the 6-1 electrode 61 and the 6-th electrode.
In the two electrodes 62, the passage holes having a larger diameter than the electron beam passage holes 22D and 22E having different diameters and passing the central electron beam G are opposed to the passage holes having a smaller diameter.

In the case of FIG. 9, for the red electron beam R, the electron beam passage hole 21D of the 6-1st electrode 61 has a large diameter, and the electron beam passage hole 21E of the 6th-2 electrode 62 has a small diameter. , About the blue electron beam B, 6-1.
The electron beam passing hole 23D of the electrode 61 has a small diameter,
The electron beam passage hole 23E of the electrode 62 has a large diameter.

By arranging the electrodes in such a shape, the effect of the present invention can be obtained even in the electrode structure shown in FIG.

Next, another embodiment of the color cathode ray tube according to the present invention will be described. In this embodiment, the thickness of the electrodes around the electron beam passage holes on both outer sides is changed.

In the present embodiment, the electrode arrangement of the electron gun uses the electrode arrangement of the electron gun 10 shown in FIG. As the focus voltages, three focus voltages having the waveforms shown in FIG. 2 are applied.

Also in the present embodiment, a configuration in which three focus voltages Ef1, Ef2, and Ef3 are supplied from the stem of the electron gun, and a split resistor is arranged on the side of the electron gun, and the split resistors are used. The fixed focus voltage Ef1 is supplied by dividing the anode voltage and the remaining focus voltage Ef1 is supplied.
Any of the configurations of supplying f2 and Ef3 from the stem portion can be adopted.

FIG. 10 is a schematic diagram showing an example of the shape of the electron beam passage hole of each of the focus electrode portions 51A, 51B, 51C in the present embodiment. In addition, the fifth
FIG. 11A is a cross-sectional view of the -1 electrode 51 (51A, 51B, 51C) cut along a horizontal plane, and FIG. 11B is a schematic perspective view showing the arrangement of through holes corresponding to three electron beams. . FIGS. 10 and 11 show a case where a cylindrical shielding body 26 is provided in the central passage hole through which the electron beam G passes.

As shown in FIG. 10, each electron beam passage hole has a circular shape having the same diameter. Then, as shown in FIG. 11, each of the 5-1st electrodes 51A, 51B, 5
On the opposing surfaces of 1C, the electron beam passing holes 21A, 21B, and 21C provided at one end (in this embodiment, the electron beam R passes) are provided with the electron beam passing holes 23A provided at the other end. , 23B, and 23C (in this embodiment, the electron beam B passes), the plate thickness of the electrode around the electron beam passage hole is different. Further, each 5-1 electrode 5
The periphery of the electron beam passage holes provided on both ends of 1A, 51B, and 51C has a different plate thickness from the periphery of the electron beam passage holes provided on the opposing surface of the 5-1 electrode. .

More specifically, the periphery of the electron beam passage holes 21A and 23A provided at both ends of the 5-1A electrode 51A is located at the both sides of the opposing 5-1B electrode 51B. The plate thickness is different from that of the periphery of 21B and 23B, and the periphery of the electron beam passage holes 21B and 23B provided at both ends of the 5-1B electrode portion 51B is the opposite of the fifth-first electrode portion 51B.
The plate thickness is different from those around the electron beam passage holes 21C and 23C provided at both ends of the 1C electrode 51C.

That is, the electron beam passage holes 21A and 21C (in this embodiment, the electron beam R) are provided at one end of the outer 5-1A electrode 51A and the 5-1C electrode 51C.
Is passed through), and the periphery of the electron beam passage holes 22A and 22C (through which the electron beam G passes) provided in the center is the small plate thickness, and the electron provided at the other end is provided. The periphery of the beam passing holes 23A and 23C (in this embodiment, the electron beam B passes) is large in thickness. On the other hand, the periphery of the electron beam passage hole 21B (in this embodiment, the electron beam R passes) provided on one end side of the central 5-1B electrode 51B is large, and the electron provided in the center is provided. The periphery of the beam passage hole 22B (in this embodiment, the electron beam G passes) has a small plate thickness, and the electron beam passage hole 23B provided in the other end side (in this embodiment, the electron beam B passes). The area around () is a small plate thickness.

In the case of FIGS. 10 and 11, the red electron beam R passing relatively outside the deflecting magnetic field on the right side of the screen is used to transmit the small, large, and small electron beam passing holes. , The 5th divided on the right side of the screen
A convergent lens effect occurs in the quadrupole lens of the -1 electrode 51,
The convergent lens effect which operates conventionally is strengthened. Conversely, a blue electron beam B passing relatively inside the deflection magnetic field on the right side of the screen
Passes through the electron beam passage holes having the large, small, and large plate thicknesses, so that the 5-1 electrode 51 divided on the right side of the screen is divided.
The diverging lens effect is generated in the quadrupole lens of the above, and the converging lens effect which conventionally works is weakened.

At this time, the center green electron beam G is
The 5-1B electrode 5 at the center of the divided 5-1 electrode 51
The 1B electron beam passage hole 22B is the 5-1C electrode 51C.
Is shielded by the shield 26 protruding from the third focus voltage, and is not affected by the third focus voltage Ef3 having a sawtooth-like shape.

The thickness of the 5-1B electrode 51B at the center of the 5-1 electrode divided into three may be the same around the electron beam passage holes 21B and 23B on both sides.

Even when the shield 26 is not provided, the center green electron beam G can be prevented from being affected by the third focus voltage Ef3 in the following manner. (1) The amplitude of the third focus voltage Ef3 is kept small by making the difference between the plate thicknesses around the electron beam passage holes on both sides sufficiently large, and the green electron beam G on the left and right sides of the screen.
Can be suppressed from occurring in the focus voltage. (2) The third focus voltage Ef for the green electron beam G can be reduced by reducing the plate thickness near the center electron beam passage hole or by increasing the diameter of the center electron beam G.
3 can be reduced. In addition, the above-mentioned means (1) and (2) can be adopted simultaneously.

As described above, the difference between the convergence of the electron beams due to the deflecting magnetic field, which is received by the electron beams R and B on both sides, is canceled, and the three electron beams R, G and B are canceled.
Have the same good shape. The operation on the left side of the screen is the reverse of the above-described operation on the right side of the screen.

In the above example, the focus electrodes (the 5-1st electrode 51) divided into three separate the electron beams R and B on both sides.
Is the case where one receives the convergent lens effect and the other receives the divergent lens effect. Not only in such a case, but also when both electron beams receive the convergent lens effect,
Even when both of them receive the divergent lens effect, the effect of the present invention can be obtained by the difference in the lens strength affecting the electron beams R and B on both sides. For example, when the electron beams R and B on both sides receive the convergent lens effect, the intensity of the main lens of the electron beams R and B on both sides is set in advance to be weaker than the intensity of the main lens of the central electron beam G. It is good. In the case where both lenses receive the divergent lens effect, the opposite may be performed.

Further, as still another embodiment of the present invention, an electron for a color cathode ray tube configured to give a quadrupole lens effect having different intensities to the previously proposed red electron beam R and blue electron beam B is described. It can also be applied to guns. FIG. 12 shows the respective 5-1 electrodes 51A, 51 in that case.
FIGS. 3A and 3B are schematic diagrams showing examples of the shapes of the electron beam passage holes of B and 51C. In FIG. 12, each of the electron beam passage holes on both outer sides has a vertically long or horizontally long rectangular shape, and the directions of the long side and the short side are reversed. The vertically elongated electron beam passage hole and the horizontally elongated electron beam passage hole have different sizes and areas of the rectangle in the configuration of FIG. 5 described above, but have the same size in FIG. Further, the plate thickness around the electron beam passage hole of each of the 5-1st electrodes 51A, 51B, 51C is made the same as the configuration shown in FIG.

Thus, in addition to the effect of making the periphery of the electron beam passage hole large or small in the above embodiment, the electron beam passage hole has a rectangular shape with an astigmatic shape. A dipole lens effect can be provided.

Incidentally, even in a configuration in which the thickness of the electrode around the electron beam passage hole is changed, the third focus voltage E
The waveform voltage shown in FIG. 6A or FIG. 6B can be used for f3.

The configuration in which the thickness of the electrode around the electron beam passage hole is changed is similar to that of the fourth electrode 14 shown in FIG.
Can also be applied to the electron gun 10 divided into two parts.

Further, the sixth electrode 16 previously shown in FIG.
The present embodiment can be applied to the electron gun 30 configured to be divided into the 6-1 electrode 61 and the 6-2 electrode 62. 13A and 13B show plan views of the sixth electrode 16 (61, 62) at this time, and FIG. 13C shows a cross-sectional view in a horizontal plane. 13A and 13B, the electron beam passage holes have the same circular shape with the same diameter. From FIG. 13C, the periphery of the electron beam passage holes through which the electron beams R and B on both outer sides pass respectively correspond to 6-1. Electrode 6
The first and sixth-second electrodes 62 have different plate thicknesses, and a large plate thickness portion and a small plate thickness portion are opposed to each other.

In the case of FIG. 13, for the red electron beam R, the periphery of the electron beam passage hole 21D of the 6-1st electrode 61 is large and the electron beam passage hole 2D of the 6th-2 electrode 62 is large.
1E has a small plate thickness, and the blue electron beam B has a small plate thickness around the electron beam passage hole 23D of the 6-1st electrode 61 and the electron beam passage hole 23 of the 6th-2 electrode 62.
The periphery of E has a large thickness.

By configuring the electrodes in such a shape, the effects of the present invention can be obtained even in the electrode configuration of FIG.

In the structure shown in FIG. 11A, the large-thick portion (peripheral portions of the electron beam passage holes 23A, 21B, and 23C) extends in the direction facing the 5-1 electrode 51, which is divided into three parts. However, as shown in FIG. 14, the large thickness portions of the outer electrodes 51A and 51C (the peripheral portions of the electron beam passage holes 23A and 23C) may be recessed. Further, a structure having a combination of these shapes may be employed.

As a method of forming the small plate thickness portion and the large plate thickness portion, the following method can be considered. (1) As shown in the plan view and the cross-sectional view of the 5-1B electrode 51B in FIGS. 15A and 15B, respectively, the concave portion 2 is formed around the electron beam passage hole 23B by coining press.
(2) As shown in the plan view and the cross-sectional view of the 5-1B electrode 51B in FIGS. 16A and 16B, burring press processing is performed around the electron beam passage hole 21B. To give
Method of Forming Cylindrical Projection 28 to Increase Substantially Plate Thickness (3) As shown in plan and sectional views of the 5-1B electrode 51B in FIGS. 17A and 17B, respectively, the electron beam passage hole 21B A method of increasing the plate thickness by combining two or more components such as a plate electrode material and a ring-shaped component 29 in the peripheral portion of

The electron gun for a color cathode ray tube according to the present invention is not limited to the above-described embodiment, but may take various other configurations without departing from the gist of the present invention.

[0083]

According to the above-mentioned electron gun for a color cathode ray tube according to the present invention, the difference in the convergence effect of the electron beam due to the deflection magnetic field, which affects the three electron beams, is canceled, and three electrons are emitted around the screen. A good shape of the beam is obtained at the same time. In addition, the phenomenon that red focus is degraded on the right side of the screen and blue focus is degraded on the left side of the screen is eliminated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing an electrode arrangement of an embodiment of an electron gun according to the present invention.

FIG. 2 is a diagram illustrating an example of a waveform of a focus voltage applied to the electron gun of FIG. 1;

3A to 3C are diagrams showing shapes of a 5-1st electrode of the electron gun of FIG. 1;

4A and 4B are diagrams showing a positional relationship of a 5-1 electrode of the electron gun of FIG. 1;

5A to 5C are diagrams showing shapes of a 5-1st electrode in another form of the electron gun of FIG. 1;

6A and 6B are diagrams showing still another embodiment of the waveform voltage applied to the electron gun of FIG. 1;

FIG. 7 is a schematic configuration diagram showing an electrode arrangement of another embodiment of the electron gun according to the present invention.

FIG. 8 is a schematic configuration diagram showing an electrode arrangement of still another embodiment of the electron gun according to the present invention.

9A and 9B are diagrams showing the shape of a sixth electrode of the electron gun of FIG. FIG. 9C is a diagram showing a positional relationship of a sixth electrode of the electron gun in FIG. 8.

10A to 10C are diagrams showing shapes of a 5-1st electrode of still another embodiment of the electron gun of FIG. 1;

11A and 11B are diagrams showing the positional relationship of the 5-1st electrode in the case of the embodiment of FIG.

FIGS. 12A to 12C are sectional views of another embodiment of the electron gun shown in FIGS.
It is a figure showing the shape of an electrode.

13A and 13B are diagrams showing shapes of a sixth electrode of another embodiment of the electron gun of FIG. C is a diagram showing a positional relationship of a sixth electrode in the case of the forms of FIGS. 13A and 13B.

FIG. 14 is a diagram showing a configuration in which a large-thickness portion of the 5-1st electrode in FIG. 10 is changed.

FIG. 15 is a diagram illustrating a method of changing the plate thickness of A and B electrodes.

FIG. 16 is a diagram illustrating a method of changing the plate thickness of A and B electrodes.

FIG. 17 is a diagram illustrating a method of changing the plate thickness of the A and B electrodes.

FIG. 18 is a schematic configuration diagram of an example of a conventional electron gun for a color cathode ray tube incorporating a quadrupole lens.

FIG. 19 is a schematic view of a color cathode ray tube.

[Explanation of symbols]

1, 10, 20, 30 ... electron gun, 2 ... deflection yoke, 3 ...
Glass bulb, 4 fluorescent screen, 11 first electrode, 12 second electrode, 13 third electrode, 13A third A electrode, 13B
... 3B electrode, 14 ... 4th electrode, 16 ... 6th electrode, 17
... Shield cup, 21A, 21B, 21C, 21D,
21E, 22A, 22B, 22C, 22D, 22E, 2
3A, 23B, 23C, 23D, 23E: Electron beam passage hole, 26: Shield, 27: concave portion, 28: cylindrical projection, 29: ring-shaped component, 41: 4-1 electrode, 42
... 4-2nd electrode, 51 ... 5-1th electrode, 51A ... 5th
1A electrode, 51B ... 5-1B electrode, 51C ... 5-1
C electrode, 52... 5-2 electrode, 61... 6-1 electrode, 6
2 ... 6-2 _{electrode, K, K R, K G} , K B ... cathode, R,
G, B: electron beam, Ef1: fixed focus voltage (first focus voltage), Ef2: second focus voltage, Ef3: third focus voltage

Claims (8)

[Claims] A focus electrode divided into two or more parts, wherein a size of a hole through which an outer one of three electron beams passes in the divided focus electrode is
One of the opposed divided focus electrodes has a large diameter and the other has a small diameter. In the same divided focus electrode, one of the holes through which the outer electron beam passes has a large diameter and the other has a large diameter. The electron gun for a color cathode ray tube, wherein the hole through which the outer electron beam passes has a small diameter. 2. A fixed focus voltage is applied as a first focus voltage, and a voltage obtained by superimposing a parabolic waveform voltage synchronized with horizontal deflection on the fixed focus voltage is applied as a second focus voltage. The electron gun for a color cathode ray tube according to claim 1, wherein a voltage obtained by superimposing a waveform voltage similar to a sawtooth wave synchronized with horizontal deflection on the fixed focus voltage is applied as the focus voltage. 3. The color according to claim 2, wherein the first focus voltage is applied to one of the opposing electrodes and the third focus voltage is applied to the other of the divided focus electrodes. Electron gun for cathode ray tube. 4. The method according to claim 1, wherein the first focus voltage is supplied through a resistor that divides an anode voltage, and the second and third focus voltages are supplied.
3. The electron gun for a color cathode ray tube according to claim 2, wherein the focus voltage is supplied directly from a stem portion. 5. A focus electrode having two or more divided focus electrodes, wherein, in the divided focus electrodes, the thickness of an electrode around a hole through which an outer electron beam among three electron beams passes is: One of the divided focus electrodes opposed to each other is formed thicker and the other is formed thinner. In the same divided focus electrode, the periphery of the hole through which one of the outer electron beams passes is thicker,
An electron gun for a color cathode ray tube, characterized in that the other outer side of the hole through which the electron beam passes is formed thin. 6. A fixed focus voltage is applied as a first focus voltage, a voltage obtained by superimposing a parabolic waveform voltage synchronized with horizontal deflection on the fixed focus voltage is applied as a second focus voltage, and a third focus voltage is applied. The electron gun for a color cathode ray tube according to claim 5, wherein a voltage obtained by superimposing a waveform voltage similar to a sawtooth wave synchronized with horizontal deflection on the fixed focus voltage is applied as the focus voltage. 7. The color according to claim 6, wherein the first focus voltage is applied to one of the opposing electrodes and the third focus voltage is applied to the other of the divided focus electrodes. Electron gun for cathode ray tube. 8. The method according to claim 8, wherein the first focus voltage is supplied through a resistor that divides an anode voltage, and the second and third focus voltages are supplied.
7. The electron gun for a color cathode ray tube according to claim 6, wherein the focus voltage is supplied directly from a stem portion.