JP3541637B2 - Electron gun for color cathode ray tube - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
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]
[Prior art]
Conventional color cathode ray tubes generally use a convergence-free deflection yoke (CDY), that is, a method in which the convergence of the entire screen is adjusted only by the deflection yoke without external correction, and R (red), G (green), The convergence of the three electron beams B (blue) is adjusted.
Therefore, the magnitudes of the deflection magnetic fields received by the three electron beams are different from each other.
[0003]
As shown in the schematic diagram of the cathode ray tube in FIG. 10, three electron beams R, G, and B emitted from the electron gun 1 and colliding with the peripheral portion of the phosphor screen 4 on the right and left sides of the screen are deflected by the deflection yoke 2. There is a difference in the degree of focusing action and diverging action received in the magnetic field.
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.
[0004]
Normally, the focus voltage and the like applied to the electron gun are set so that the spot shape of the central electron beam G among the three electron beams R, G, and B is optimized.
[0005]
[Problems to be solved by the invention]
In general, when designing the deflection yoke 2, for example, if the convergence of the red electron beam R and the blue electron beam B on the left and right sides of the screen is matched, as shown in FIGS. Is shifted toward the center of the screen.
Note that the direction of this shift depends on the design of the deflection yoke 2.
[0006]
Therefore, usually, in order to correct the central green electron beam G, the magnetic field distribution of the deflection yoke 2 is more complicatedly adjusted.
Therefore, as a side effect, the shape of the electron beam is distorted, the focus is deteriorated, and the convergence at the four corners of the screen is deteriorated, but it is difficult to adjust these.
[0007]
For example, when three electron beams R, G, and B collide with the right side of the screen of the phosphor 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 screen of the fluorescent screen 4, the electron beam B is more affected by the deflection magnetic field formed by the deflection yoke 2 than the electron beams G and R. Receive strongly. As a result, the distortion of the beam spot of the electron beam B on the phosphor screen 4 becomes larger than that of the other electron beams R and G.
[0008]
In order to solve the above-mentioned problem, in the present invention, the center electron beam can be adjusted by the electron gun, so that the deflection yoke and the electron gun adjust the three electron beams to the optimum state, An object of the present invention is to provide an electron gun for a color cathode-ray tube in which distortion of a beam is small and focus deterioration at a peripheral portion of a screen is small.
[0009]
[Means for Solving the Problems]
The electron gun for a color cathode ray tube according to the present invention has a focus electrode divided into two, and a hole through which a central electron beam among the three electron beams passes is formed on the opposing surfaces of each of the divided focus electrodes. Are formed so as to be deviated from the center of the electrode in the direction of the electron beam on the outer side opposite to each other.
[0010]
Another electron gun for a color cathode ray tube according to the present invention has a focus electrode divided into three, and a hole through which a central electron beam among three electron beams passes on opposing surfaces of the focus electrode divided into three. However, the focus electrodes on both outer sides are formed so as to be deviated from the center of the electrode in the direction of one outer electron beam, and the center focus electrode is formed so as to be deviated from the center of the electrode in the direction of the other outer electron beam. Configuration.
[0011]
According to the above-described respective configurations of the present invention, the holes through which the central electron beam passes are biased in the direction of the outer electron beam on the opposite side on the opposing surfaces of the focus electrode divided into two or three. By being formed, the path of the central electron beam can be adjusted independently.
Therefore, even if the position of the spot of the central electron beam is shifted from the spots of the electron beams on both outer sides due to the action of the deflection yoke, the position of the spot of the central electron beam can be corrected.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention has a focus electrode divided into two, and a hole through which a central electron beam among the three electron beams passes is opposed to each other from the electrode center on opposing surfaces of each of the divided focus electrodes. Is an electron gun for a color cathode ray tube which is formed so as to be deviated in the direction of the electron beam on the outside.
[0013]
Further, according to the present invention, in the electron gun for a color cathode ray tube, a fixed focus voltage is applied to one of the two divided focus electrodes, and the other focus electrode is synchronized with the fixed focus voltage by horizontal scanning of the deflection yoke. A voltage on which a voltage having a waveform similar to that of the saw blade is superimposed is applied.
[0014]
According to the present invention, in the electron gun for a color cathode ray tube, a fixed focus voltage is applied to a focus electrode on the anode side.
[0015]
The present invention has a focus electrode divided into three, and a hole through which a central electron beam among the three electron beams passes on opposite surfaces of the focus electrode divided into three is formed on both outer sides of the focus electrode. In the above, the electron gun for a color cathode ray tube is formed so as to be deviated from the center of the electrode in the direction of the electron beam on one side, and the center focus electrode is formed so as to be deviated from the center of the electrode in the direction of the electron beam on the other side. It is.
[0016]
Further, according to the present invention, in the electron gun for a color cathode ray tube, a fixed focus voltage is applied to both outer focus electrodes of the three divided focus electrodes, and a horizontal scan of a deflection yoke is performed to a fixed focus voltage at a center focus electrode. A configuration in which a voltage in which a voltage having a waveform similar to that of a synchronized saw blade is superimposed is applied.
[0017]
Conventionally, the convergence of the three electron beams R, G, and B on the left and right sides of the screen is adjusted by the deflection yoke 2, but in the present invention, the electron gun 1 further provides the green electron beam G shown in FIGS. Correct the deviation.
[0018]
Prior to description of an embodiment of an electron gun for a color cathode ray tube of the present invention, a comparative example of an electron gun for a color cathode ray tube to which the present invention is applied will be described.
FIG. 13 shows a schematic configuration diagram of a comparative example of an electron gun for a color cathode-ray tube incorporating a quadrupole lens which is generally widely used.
The electron gun 70 has three cathodes K _R , K _G , and K _B arranged in parallel and in-line. From the cathodes K (K _R , K _G , K _B ) toward the anode, the first cathodes K _R , K _G , and K _B. The electrode 11, the second electrode 12, the third electrode 13, the fourth electrode 14, the fifth electrode, the sixth electrode 16, and the shield cup 17 are sequentially coaxially arranged. The fifth electrode is divided into two, a 5-1 electrode 51 and a 5-2 electrode 52. The second electrode 12 and the fourth electrode 14 are electrically connected.
[0019]
For example, a voltage of 0 V (or several tens of V) is applied to the first electrode 11, and a voltage of 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 sixth electrode 16.
[0020]
An electrode surface 151 having vertically elongated electron beam passage holes 151A, 151B, 151C as shown in FIG. 14A is provided on the surface of the 5-1st electrode 51 facing the 5-2nd electrode 52. ing. On the other hand, on the surface of the 5-2 electrode 52 facing the 5-1 electrode 51, an electrode surface 152 having horizontally elongated electron beam passage holes 152A, 152B, 152C as shown in FIG. 14B is provided. Have been.
[0021]
In this color cathode-ray tube electron gun 70, the 5-1 electrode 51, through the stem portion, for example, a constant focus voltage F _c of 5kV~7kV is applied. On the other hand, the third electrode 13 and the 5-2 electrode 52, the focusing electrode F parabolic waveform voltage synchronized e.g. amplitude 500~1000V the horizontal deflection of the _c and the focus voltage F _c and is superimposed voltage F _v ( (See FIG. 15).
[0022]
Thereby, a quadrupole lens (not shown) is formed between the 5-1 electrode 51 and the 5-2 electrode 52, and the quadrupole lens is formed by the 5-2 electrode 52 and the sixth electrode 52. A change in intensity occurs in a main electron lens formed between the lens and the so-called focus lens (not shown). As a result, it is possible to improve the shape of the electron beam in the peripheral portion of the phosphor screen 4 in the left-right direction.
[0023]
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), while It receives a focusing action (convex lens effect) in the horizontal direction (lateral direction). 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.
[0024]
The effect of providing the quadrupole lens in this manner is significant.
This method of simultaneously operating the quadrupole lens and the above-mentioned voltage F _v (so-called dynamic focus voltage) is widely used for displays, large-sized TVs, and high-definition TVs and electron guns for color cathode ray tubes.
[0025]
Next, an embodiment of an electron gun for a color cathode ray tube according to the present invention will be described with reference to the drawings.
The electron gun 10 for a color cathode ray tube shown in FIG. 1 has three cathodes K _R , K _G , and K _B arranged in parallel in a line, and the cathode K (K _R , K _G , K _B ) is connected to the anode side. , The first electrode 11, the second electrode 12, the third electrode 13, the fourth electrode 14, the fifth electrode, the sixth electrode 16, and the shield cup 17 are sequentially coaxially arranged.
[0026]
The fifth electrode corresponding to the focus electrode is divided into two, a 5-1 electrode 51 and a 5-2 electrode 52, and the 5-1 electrode 51 is further divided into a 5-1A electrode 51A and a 5-1A electrode 51A. -1B electrode 51B.
[0027]
The electrode structure of the color cathode ray tube electron gun 10 is different from the color cathode ray tube electron gun 70 shown in FIG. 13 in that the 5-1 electrode 51 is used instead of the 5-1 electrode 51 which is the focus electrode. This corresponds to a configuration divided into two.
[0028]
Similarly to the color cathode ray tube electron gun 70 shown in FIG. 13, a voltage of, for example, 0 V (or several tens of V) is applied to the first electrode 11, and 200 to 200 V is applied to the second electrode 12 and the fourth electrode 14. A voltage of 800 V is applied. An anode voltage of, for example, 22 kV to 30 kV is applied to the fifth electrode 16.
[0029]
In the electron gun 10 having the structure shown in FIG. 1, the shape of the electron beam passage hole on the side of the 5-2 electrode 52 of the 5-1 electrode 51 is shown in FIG. FIG. 2B shows the shapes of the electron beam passage holes on the side.
FIG. 3 is a cross-sectional view of the 5-1 electrode 51 (51A, 51B) and the 5-2 electrode 52, which are divided into two, cut on a horizontal plane.
[0030]
In FIG. 2A, electron beam passage holes 251R, 251G, and 251B are provided on the electrode surface 251 corresponding to the three electron beams R, G, and B, respectively.
In FIG. 2B, electron beam passage holes 252R, 252G, and 252B are provided on the electrode surface 252 corresponding to the three electron beams R, G, and B, respectively.
[0031]
The shapes of the electron beam passage holes 251R, 251G, 251B and 252R, 252G, 252B shown in FIG. 2A and FIG. Although the shape is a perfect circle or another shape having no feature, in the electron beam passage holes 251G and 252G corresponding to the green electron beam G, the interval between the other electron beam passage holes differs between FIGS. 2A and 2B. I have.
Therefore, the electron beam passage hole (that is, the center) corresponding to the green electron beam G is closer to the transmission hole 251B of the blue electron beam B than the center O of the electrode in FIG. 2A, and is red from the center O of the electrode in FIG. 2B. Are formed on the transmission hole 252R side of the electron beam R.
[0032]
That is, in the present embodiment, as shown in FIG. 3, the green electron beam passage hole provided at the center of the 5-1A electrode 51A on the cathode side of the 5-1 electrode 51 divided into two parts, as shown in FIG. 22A is provided so as to be deviated toward the blue electron beam passage hole 23A (see the electrode surface 251 in FIG. 2A). On the other hand, in the 5-1st electrode 51B on the anode side, the green electron beam passage hole 22B provided at the center is provided so as to be biased in the direction of the red electron beam passage hole 21B (see the electrode surface 252 in FIG. 2B). ).
[0033]
The green electron beam passage holes 22A and 22B provided at the center of the two 5-1 electrodes 51A and 51B are biased in different directions, and the red and blue electron beam passage holes 21A provided on both outer sides. And 21B, and 23A and 23B at the same position, the green electron beam G can be adjusted independently of the electron beams R and B on both outer sides.
[0034]
As shown in FIG. 3, on the anode side of the 5-1st electrode 51, that is, on the surface of the 5-1B electrode facing the 5-2nd electrode 52, as shown in FIG. The electrode surface 151 provided with the vertically long astigmatic electron beam passage holes 151A, 151B, 151C shown in FIG.
On the other hand, on the cathode side of the 5-2nd electrode 52, that is, on the surface opposed to the 5-1B electrode 51B, similarly to the electron gun 70 of FIG. 13, the horizontally long astigmatic electron beam passage hole 152A shown in FIG. , 152B, and 152C are formed.
[0035]
Then, the first 5-1B electrode 51B of the two divided anode side of the 5-1 electrode 51, through the stem portion, for example, a fixed focus voltage F _c of 5kV~7kV is applied. On the other hand, the third electrode 13. and the 5-2 electrode 52, voltage is for example amplitude synchronized with the horizontal deflection of the parabolic shape of 500~1000V fixed focus voltage F _c and the fixed focus voltage F _c is superimposed The voltage _Fv-1 is applied (see FIG. 5A).
[0036]
Thereby, a quadrupole lens (not shown) is formed between the 5-1B electrode 51B and the 5-2 electrode 52, and the quadrupole lens is formed by the 5-2 electrode 52 and the sixth electrode 52. A change in intensity occurs in a main electron lens formed between the lens and the so-called focus lens (not shown). As a result, although not shown, the electron beam in the peripheral portion of the phosphor screen in the left-right direction can be formed in a more favorable shape.
[0037]
Further, in the present embodiment, furthermore, the two divided cathode side of the 5-1 electrode in the first 5-1A electrode 51A, for example, the amplitude is synchronized with the horizontal deflection of the fixed focus voltage F _c is ± 50 V A voltage _Fv-2 in which a waveform voltage having a shape similar to a saw blade and a fixed focus voltage _Fc are superimposed is applied (see FIG. 5B).
[0038]
Thus, in the 5-1 electrode 51 which is divided into two parts, is first 5-1B electrode 51B to a fixed focus voltage F _c of anode side is applied, fixed focus voltage F _c to the 5-1A electrode 51A of the cathode side By applying the above-described voltage _Fv-2 on which a waveform voltage having a shape similar to a saw blade synchronized with the horizontal deflection is superimposed, for example, as shown in FIG. , And has an effect of bending the green electron beam G.
[0039]
With this configuration, as shown in FIG. 6, the center green electron beam G on the left and right sides of the screen is relatively shifted from the position of the broken line as compared with the electron beams R and B on both sides as indicated by arrows. The convergence of the three electron beams R, G, and B can be matched because the electron beams move outward in the screen.
[0040]
When giving a voltage waveform in which the sign is inverted from that of the focus voltage waveform _Fv-2 shown in FIG. 5B and + and-are reversed, the arrangement of the beam holes shown in FIGS. 2A and 2B is reversed. I do.
[0041]
According to the electron gun 10 of the above-described embodiment, the adjustment of the center green electron beam G by the electron gun 10 can be performed independently of the electron beams R and B on both outer sides. Of the three electron beams R, G, and B on the left and right sides of the screen by combining the adjustment of the electron beams G and the adjustment of the red and blue electron beams R and B mainly on both sides by the deflection yoke 2. Can be easily performed.
[0042]
As a result, the electron beam receives less distortion than the color cathode ray tube of the comparative example, the focus is less deteriorated in the peripheral portion of the screen, and a uniform resolution can be obtained over the entire screen.
[0043]
Next, another embodiment of the electron gun for a color cathode ray tube according to the present invention will be described.
The present embodiment is a case where the focus electrode is divided into three, that is, a case where the 5-1st electrode 51 is divided into three.
[0044]
The electron gun 20 shown in FIG. 7 has three cathodes K _R , K _G , and K _B arranged in line in parallel, and the first cathodes K _R , K _G , and K _B are arranged in the first direction from the cathodes K _R , K _G , and K _B to the anode side. The electrode 11, the second electrode 12, the third electrode 13, the fourth electrode 14, the fifth electrode, the sixth electrode 16, and the shield cup 17 are sequentially coaxially arranged.
[0045]
The fifth electrode corresponding to the focus electrode is divided into two, a 5-1 electrode 51 and a 5-2 electrode 52, and the 5-1 electrode 51 is further divided into a 5-1A electrode 51A and a 5-1A electrode 51A. -1B electrode 51B and a 5-1C-th electrode 51C.
[0046]
The three divided 5-1 electrodes 51, that is, the 5-1A electrode 51A, the 5-1B electrode 51B, and the 5-1C electrode 51C are provided with three electron beam passage holes, respectively. These three electron beam passage holes are provided such that the center electron beam passage hole is biased in the direction of one side of the electron beam passage hole, as shown in FIGS. 2A and 2B in the previous embodiment.
[0047]
Here, FIG. 8 is a cross-sectional view of the 5-1 electrode 51 (51A, 51B, 51C) and the 5-2 electrode 52, which are divided into three, cut on a horizontal plane.
As shown in FIG. 8, in the present embodiment, of the 5-1A electrode 51A and the 5-1C electrode 51C at both ends of the 5-1 electrode 51 divided into three, the green color provided at the center is provided. The electron beam passage holes 22A and 22C are provided in a direction toward the blue electron beam passage holes 23A and 23C, like the electrode surface 251 shown in FIG. 2A.
On the other hand, in the center 5-1 electrode 51B, the green electron beam passage hole 22B provided in the center is biased toward the red electron beam passage hole 21B as in the electrode surface 252 shown in FIG. 2B. Provided.
[0048]
With this configuration, the center green electron beam G can be adjusted independently of the outer electron beams R and B, as in the previous embodiment.
[0049]
Further, 3 to split the 5-1A electrode 51A and the 5-1C electrode 51C of the both outer sides of the 5-1 electrode 51, fixed focus voltage F _c is applied.
Further, the voltage F _v-1 where the voltage of a synchronized parabolic shape in the horizontal deflection and fixed focus voltage F _c is superimposed fixed focus voltage F _c is applied to the third electrode 13 5-2 electrode 52 .
Furthermore, 3 in the divided center of the 5-1B electrode 51B of the 5-1 electrode 51, fixed focus voltage F is the waveform voltage of similar shape to the saw blade in synchronism with the horizontal deflection fixed focus voltage of _c F _c voltage F _v-2 superimposed on is applied.
Each of the voltage waveforms is, for example, the voltage waveforms _Fc , _Fv-1 , and _Fv-2 shown in FIGS. 5A and 5B, as in the previous embodiment.
[0050]
In the electron gun of the present embodiment, other configurations (including the applied voltage) are the same as those of the conventional electron gun 10 shown in FIG. I do.
[0051]
With the above-described configuration, for example, as shown in FIG. 9, the potential distribution becomes asymmetric with respect to the green electron beam G, and an effect of bending the green electron beam G is exerted.
Therefore, similarly to the electron gun 10 of the previous embodiment, the center green electron beam G on the left and right sides of the screen moves relatively toward the outside of the screen as compared with the electron beams R and B on both sides. The convergence of the beams R, G, B can be matched.
Further, the center electron beam G can be adjusted by the electron gun 20 independently of the outer electron beams R and B, so that the adjustment of the green electron beam G by the electron gun 20 and the deflection yoke 2 can be performed. , The convergence of the three electron beams R, G, and B on the left and right sides of the screen can be easily adjusted.
[0052]
Further, as in the present embodiment, the 5-1st electrode is divided into three, and the fixed focus voltage _Fc and the waveform voltage _{Fv-2 are} applied between the outer electrodes 51A and 51C and the center electrode 51B. , The adjustment of the central electron beam G can be performed more effectively than the case where the two-divided 5-1st electrode is provided as in the above embodiment.
[0053]
The arrangement of the focus electrode divided into two or three and the applied voltage waveform are not limited to the above embodiments, but preferably, the solid focus voltage _Fc is applied to the divided focus electrodes. The electrode to be used is arranged closest to the anode, so that the influence on the subsequent quadrupole lens and the main lens is reduced.
[0054]
In each of the above-described embodiments, the case where the present invention is applied to an electron gun for a color cathode ray tube having a quadrupole lens is described. It can be applied to an electron gun.
For example, a configuration in which a focus electrode divided into two or three is provided immediately on the cathode side of the main lens, and a central electron beam passage hole is formed so as to be biased in opposite directions to each other on opposing surfaces of each focus electrode. Can also be taken.
[0055]
The electron gun for a color cathode ray tube of the present invention is not limited to the above-described embodiments, and may take various other configurations without departing from the gist of the present invention.
[0056]
【The invention's effect】
According to the above-mentioned electron gun for a color cathode ray tube according to the present invention, the focus electrodes divided into two or three are arranged, and the passing holes of the central electron beam are mutually separated on the opposing surfaces of the divided focus electrodes. By being formed so as to be biased toward the outer electron beam on the opposite side, the center electron beam can be adjusted independently of the outer electron beam.
[0057]
Furthermore, when the fixed focus voltage and a voltage obtained by superimposing a fixed focus voltage on a waveform voltage having a shape similar to a saw blade synchronized with horizontal deflection of the fixed focus voltage are respectively applied to the divided focus electrodes, The deviation of the spot position between the center electron beam and the outer electron beams can be corrected.
[0058]
Therefore, it is possible to easily adjust the convergence of the three electron beams on the left and right sides of the screen.
As a result, the electron beam receives less distortion than the conventional color cathode ray tube, the focus is less deteriorated at the peripheral portion of the screen, and a uniform resolution can be obtained over the entire screen.
[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.
2A and 2B are diagrams showing an example of the shape of an electron beam passage hole of an 5-1st electrode of the electron gun of FIG.
3A and 3B are cross-sectional views showing the shape of a 5-1 electrode of the electron gun of FIG.
FIG. 4 is a diagram showing a state in which a central electron beam in the electron gun of FIG. 1 passes through 5-1.
5A and 5B are diagrams showing examples of a waveform of a focus voltage applied to a focus electrode of the electron gun of FIG. 1;
FIG. 6 is a diagram illustrating that a central electron beam is corrected.
FIG. 7 is a schematic configuration diagram showing an electrode arrangement of another embodiment of the electron gun according to the present invention.
8A and 8B are cross-sectional views showing the shape of the 5-1st electrode of the electron gun of FIG.
FIG. 9 is a diagram showing a state in which a central electron beam in the electron gun of FIG. 7 passes through 5-1.
FIG. 10 is a schematic view of a color cathode ray tube.
FIG. 11 is a front view showing irradiation positions of three electron beams on a phosphor screen.
FIG. 12 is a sectional view showing irradiation positions of three electron beams on a phosphor screen.
FIG. 13 is a schematic configuration diagram of a comparative example of an electron gun for a color cathode ray tube incorporating a quadrupole lens.
14A and 14B are diagrams showing shapes of focus electrodes constituting a quadrupole lens of the electron gun of FIG.
FIG. 15 is a diagram illustrating an example of a waveform of a focus voltage applied to a focus electrode of the electron gun of FIG. 13;
[Explanation of symbols]
1, 10, 20 electron gun, 2 deflection yoke, 3 glass bulb, 4 phosphor screen, 11 first electrode, 12 second electrode, 13 third electrode, 14 fourth electrode, 16 sixth electrode, 17 shield cup, 21A , 21B, 21C, 22A, 22B, 22C, 23A, 23B, 23C Electron beam passage hole, 515-1 electrode, 51A 5-1A electrode, 51B 5-1B electrode, 51C 5-1C electrode, 525-2 electrode , 70 electron _{gun, K, K R, K G} , K B cathode, R, G, B electron beams, F _c fixed focus voltage

Claims (5)

It has a focus electrode divided into two,
On the opposing surfaces of each of the two divided focus electrodes, a hole through which the center electron beam among the three electron beams passes is formed so as to be deviated from the center of the electrode in the direction of the outer electron beams opposite to each other. An electron gun for a color cathode ray tube. A fixed focus voltage is applied to one of the two divided focus electrodes, and a voltage having a waveform similar to a saw blade synchronized with horizontal scanning of the deflection yoke is superimposed on the fixed focus voltage on the other focus electrode. 2. The electron gun for a color cathode ray tube according to claim 1, wherein the applied voltage is applied. 3. The electron gun for a color cathode ray tube according to claim 2, wherein the fixed focus voltage is applied to the focus electrode on the anode side. It has a focus electrode divided into three,
On the opposing surfaces of the three divided focus electrodes, a hole through which the center electron beam among the three electron beams passes is formed in the outer focus electrodes. Is formed biased in the direction,
The electron gun for a color cathode ray tube, wherein the focus electrode at the center is formed so as to be deviated from the center of the electrode toward the electron beam on the other side. Of the three divided focus electrodes, a fixed focus voltage is applied to the outermost focus electrodes, and a waveform similar to a saw blade synchronized with horizontal scanning of the deflection yoke is applied to the center focus electrode at the fixed focus voltage. The electron gun for a color cathode ray tube according to claim 4, wherein a voltage on which a voltage is superimposed is applied.

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