JPH02265151A - Color television picture tube apparatus - Google Patents

Abstract

PURPOSE:To obtain high image resolution at the whole of the screen by correcting strain of beam spots due to a deflecting magnetic field by altering strength and weakness of a second electron lens in a first deflecting region where deflection degree is small and altering strength and weakness of a first electron lens in a second deflecting region where deflection degree is large. CONSTITUTION:A second parallel and plane lens L2 is weakened in a region where deflection degree of horizontal deflection angle is comparatively small and divergent angle of a beam entering into a large diameter lens L3 is extended and changed to under focusing direction as compared to that without deflection. A first parallel plane lens L1 is strengthened in a region where deflection degree of horizontal deflection angle is comparatively large and a second cross-over is formed between the first parallel plane lens L1 and the large diameter lens L3, rediverges, and enters in the large diameter lens L3 and therefore the beam is changed to under focusing direction largely as compared to that without deflection. Consequently, an electron beam is changed to over-focus direction and just-focused on a screen. By this method excellent beam spots at the whole screen are achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) The present invention relates to a three-electron beam type color picture tube device.

(Prior Art) In general, the mainstream color picture tube is what is called a three-electron gun type. Among these, an in-line type electron gun in which three electron guns are arranged in a row is used, and the horizontal deflection magnetic field is
), the vertical deflection magnetic field is applied in a vinction-like manner as shown in Figure 7 (
As shown in b), the three electron beams are self-converged by creating nonuniform magnetic fields that are each distorted into a barrel shape. Color picture tubes using this self-concentration method can reduce power consumption, which greatly contributes to improving the quality and performance of color picture tubes.
Currently, it is the mainstream color picture tube for general use.

On the other hand, the non-uniformity of the deflection magnetic field as described above has the disadvantage of lowering the resolution in the periphery of the screen of the color picture tube.

That is, the cross-sectional shape of the electron beam is distorted according to the deflection angle of the electron beam, and as shown in FIG. Beam spot 0 has a shape including a horizontally long elliptical high-brightness core portion (6) and a vertically long low-brightness halo portion ω, and the resolution at the periphery of the screen is significantly reduced.

The above-mentioned distortion of the electron beam spot is caused by the fact that the deflection yoke in the self-concentration system
Due to the application of a non-uniform magnetic field as shown in Figures (a) and (b), the electron beam within the deflection magnetic field is less focused in the horizontal direction, and conversely more focused in the vertical direction. It has become.

Such a decrease in resolution due to deflection distortion can be reduced by reducing the diameter of the electron beam passing through the main lens and the deflection magnetic field. For this purpose, a method is generally used to strongly focus the electron beam using a prefocus lens, but this has the disadvantage that the crossover diameter increases and the diameter of the electron beam aperture in the center of the screen increases. .

Alternatively, the prefocus lens can be made an asymmetrical lens,
Deflection distortion can also be reduced by keeping the electron beam underfocused in the vertical direction at the center of the screen.

In this case, the electron beam spot 1~ at the center of the screen generally has an elliptical shape with its long axis in the vertical direction, which also causes a reduction in resolution at the center of the screen.

Alternatively, the electron beam spot diameter at the periphery of the screen can be improved by a method of changing the intensity of the electron lens in synchronization with the deflection, a so-called dynamic focus method.

Such dynamic focusing methods include dynamically changing the divergence angle of the electron beam in the vertical direction in a prefocus lens or sublens;
There is a method that dynamically changes the vertical focusing power of the main lens, but in either method, the vertical diameter of the electron beam within the deflection magnetic field is larger when deflecting at the periphery of the screen than when deflecting at the center of the screen. Therefore, in a region where the deflection angle is particularly large, the electron beam is subjected to a larger deflection aberration, resulting in a disadvantage that the effect of improving the beam spot diameter becomes smaller.

The deflection aberration experienced by the electron beam is greater due to the horizontal deflection magnetic field than the vertical deflection magnetic field, so this drawback becomes a problem especially when scanning a horizontally long screen with a wide internal angle, such as on a high-definition television. The beam spot diameter deteriorates at the outermost edge of the screen in the horizontal direction and the outermost diagonal of the screen, resulting in a decrease in resolution.

As described above, the region where the effect of dynamic focusing is small varies somewhat depending on the electron gun and deflection yoke method, dimension, etc., but it is a problem when the horizontal deflection angle is about 90° or more.

As shown in Figures 12(a) and 12(b), this is approximately 10% of the total screen (in Figure 12(a)) when the screen aspect ratio is 4:3 and the deflection is 100°. (shaded area),
Aspect ratio [6:9.1] corresponds to about 20% of the entire screen (shaded area in FIG. 12(b)) in the case of 0° deflection.

Therefore, this is a problem particularly in the case of an aspect ratio of 16:9, and becomes a big problem in high-definition television cathode ray tubes that require high resolution up to the periphery of the screen.

(Problems to be Solved by the Invention) As described above, the prior art has a problem in that the beam spot diameter deteriorates at the outermost edge in the horizontal direction of the screen and the outermost edge in the diagonal direction of the screen during wide-angle deflection.

The present invention provides a color picture tube device that has high resolution from the center of the screen to the outermost edge of the screen even when the deflection angle is large or on a horizontally long screen such as a high-definition television.

[Structure of the invention]

(Means for Solving the Problems) The electron gun section of the color picture tube device according to the present invention has at least two electron lenses, a first and a second electron lens,
In the first deflection region where the amount of deflection is small, the strength of the second electron lens is changed to reduce beam deflection by the deflection magnetic field.
In the second deflection region where the amount of deflection is large, the strength of the first electron lens is changed to correct the distortion of the beam 11 spot 1 caused by the deflection magnetic field.

Particularly in areas where the amount of deflection is large, the diameter of the beam spot in the deflection magnetic field is reduced, so even when the amount of deflection is large, the deflection aberration can be reduced and good beam spotting can be obtained.

(Function) The vertical focusing state of the electron beam by the electron gun of the color picture tube device of the present invention is shown in equivalent optical models in FIGS. 2, 3, and 4. FIG. 2 shows a case where the electron beam is not deflected, FIG. 3 shows a case where the amount of deflection is small, and FIG. 4 shows a case where the amount of deflection is large.

When the electron beam is not deflected, the electron beam generated at the cathode is focused on the prefocus lens P, as shown in Figure 2.
After being focused to some extent by L, the first lens I, □, and the second lens 1.2, the light is focused by the third lens L3 and becomes a focus from 1 to 1 on the screen.

When the amount of deflection is small, the second lens L2 is weakened as shown in FIG. Therefore, the electron beam generated at the cathode is transmitted through the prefocus lens circle 7 and the first lens L.
The light is hardly focused by the lens L2 of the rear section 2, which has been focused by the mechanical process, and is focused by the third lens L3. Therefore, if there is no deflection magnetic field, the screen will be under-focused, but due to the deflection magnetic field, it will receive a force in the over-focus direction and will be brought into just focus.

When the amount of deflection is large, the -th lens is strengthened, and the second lens remains weakened, as shown in FIG.

Therefore, the electron beam generated at the cathode is focused by the prefocus lens PL and then largely focused by the first lens L1, and the electron beam is then focused by the first lens 1, □ and the third lens 1,
A crossover point occurs between 3 and 3.

Almost no electron beam is focused by the second lens 1.2, but is focused by the third lens L3. For this reason, the virtual object point position in the third lens L3 moves largely toward the screen, resulting in underfocus on the screen in the absence of a deflection magnetic field.

In reality, it receives a force in the overfocus direction due to the deflection magnetic field, and the focus changes from just 1 to focus. In addition, in this case, the vertical diameter D3 of the electron beam within the deflection magnetic field is much smaller than the diameter when it is not deflected (D□ in Figure 2), so if the amount of deflection is large, the deflection the electron beam receives Aberrations are reduced, and it is possible to easily achieve just focus on the screen even at fairly large deflection angles.

Regarding the horizontal focusing of the electron beam, the deterioration of the spot diameter due to the deflection magnetic field is small, so changing the strength of the first lens L□ and the second lenses 1 and 2 will not change the focusing state of the electron beam. We have to make sure that we don't do that. For this purpose, the first lenses I, □ and the second lenses 1, 2 are lenses having opposing electrodes as shown in FIG. 10, and act only in the vertical direction.

(Example) FIG. 1 shows a cross section of a part of the screen portion near the neck portion of a color picture tube device in which the present invention is implemented, taken along the plane X-2.

In Fig. 1, the electron gun section (100) disposed in the neck (c) includes a cathode K, a first grid Gx + a second grid G21, a third grid G3 + a fourth grid G41, a fifth grid The electron gun (100) consists of the GSI 6th grid GCt, the 7th grid G7 + the 8th grid G8, the insulating support BG that supports them, and the valve spacer (112), and the electron gun (100) has a stem pin (], 1
．． 3) is fixed.

Each of the cathodes has a heater inside and generates three electron beams BRI BG+ BB.

Further, the first grid Gx and the second grid G2 have three relatively small beam passing holes corresponding to the three cathodes K, and in these parts, the electron beams from the cathodes K are controlled and accelerated, so-called electron This becomes the beam forming section GE. The third grid G3 (on the side opposite G2) then likewise has three relatively large circular beam passage holes, as shown in FIG. 9, corresponding to the three cathodes K.

In addition, the fourth grid side electrode of the third grid G3, the fourth grid G41, the fifth grid GSI, the sixth grid 1 and GG+
The beam passage hole of the electrode on the side of the sixth grid I of the seventh grid G7 is common to all three electron beams, as shown in FIG. It has become. Therefore, the unipotential lens formed from the third grid G3, the fourth grid G4, and the fifth grid G5, and the unipotential lens formed from the fifth grid GSI, the sixth grid GG, and the seventh grid G7 are almost lenses in the horizontal direction. It is a so-called parallel plate lens, which has no focusing effect but only has a focusing effect in the vertical direction.

In the middle of the seventh grid G7 near the eighth grid GB side, there is an electrode (G7D) with three non-circular openings as shown in FIG. ) is provided.

The 8th grid Gll partially overlaps with the 7th grid G7,
It is a substantially cylindrical electrode that includes a seventh grid G7, which is a cylindrical electrode, and substantially forms a large diameter circular lens between it and the large circular beam passage hole (G7T) of the seventh grid G7. .

A valve spacer = (
112), which is in contact with the conductive film (10) coated from the inner wall of the funnel (A) to the inner wall of the neck 0, and a high voltage is supplied to the anode from the anode terminal provided on the funnel. There is. A magnetic field correction element for the magnetic field produced by the deflection yoke can also be placed at the tip of the eighth grid GB. The first grid G□ to the eighth grid G8 are fixedly supported on the cathode by the insulating support BG.

In addition, a deflection yoke ■ is attached from the neck (C) to the funnel (A), and includes a horizontal deflection coil and a vertical deflection coil to deflect the three electron beams BR, Bc+BB from the electron gun horizontally and vertically. Consists of. Furthermore, a multipolar magnet (51) is arranged for adjusting the trajectory of the beam.

In the above electrode configuration, for example, the cathode has about 15
The cutoff voltage is set to 0, and a video signal is added to this, the first grid G1 is set to ground potential, and the second grid G2 is set to 5
00V-IKV, 3rd grid G is 5-10KV, 4th grid G4 is 2-10KV, 5th grid G5 is 5
-10 KV, the sixth grid G6 applies 3-10 KV, the seventh grid G7 applies 5-10 KV, and the eighth grid G8 applies an anode high voltage of 25-35 KV.

Furthermore, voltages that change in synchronization with the deflection are applied to the fourth grid G4 and the sixth grid 1-65, as shown in FIGS. 5 and 6, respectively.

That is, the voltage VD2 applied to the fourth grid G4 shown in FIG. If the horizontal deflection angle is approximately 90 degrees or more and the amount of deflection is relatively large, the voltage will be reduced by 1 to 5 KV. Also,
Voltage VD applied to the sixth grid G, i shown in FIG.
When the deflection amount is small and the horizontal deflection angle is about 90° or less, the deflection becomes a parabolic shape that increases between about 3 and 10 KV as the deflection amount increases, and the horizontal deflection angle is about 90°.
When the above deflection amount is large, the voltage becomes a constant voltage of 5~], OKV.

With such a potential configuration, the beam generated from each cathode forms a first crossover between the first grid Gel and the second grid G2, and is then transferred to the second grid Ge.
The light is focused by the prefocus lens of the third grid G3 and enters the third grid G3.

3rd grid G3 + 4th grid G41 5th grid G
5 (referred to as the first parallel plate lens) and the unipotential lens formed by the fifth grid GSI, the sixth grid GGI, and the seventh grid G7 (referred to as the second parallel plate lens) are as described above. As shown above, since these lenses act only in the vertical direction, in the horizontal direction of the beam, the sixth lens is not affected by these lenses.
The large diameter lens formed by the grid Gb+the seventh grid G7 receives a focusing action and the beams on both sides are focused and concentrated on the screen.

Next, vertical focusing of the beam will be explained.

In the case of no deflection, the first parallel plate lens exhibits a weak focusing effect, and the second parallel plate lens exhibits a strong focusing effect.

Therefore, the beam incident on the third grid G3 is
7th grid 7F after being focused by the parallel plate lenses of
It is focused by a large-diameter lens formed by G7 and 8th Grits 1 to G6, and then focused on Jas 1 on the screen.

In a region where the amount of deflection is relatively small, where the horizontal deflection angle is about 90 degrees or less, the potential to the sixth grid 1 increases and the potential difference between the fifth and seventh grid potentials becomes small, so the second parallel plate lens is weakened. , the divergence angle of the beam incident on the large-diameter lens increases, and changes to the direction of underfocus compared to the case without deflection. Since this electron beam receives a force in the overfocus direction due to the deflection magnetic field, it is brought into just focus on screen 2.

In a region where the horizontal deflection angle is approximately 90° or more and the amount of deflection is relatively large, the fourth grid potential is low, so the first parallel plate lens is strengthened, and the first parallel plate lens and large diameter lens are In between, a second crossover is formed, and the light diverges again and enters the large aperture lens. Therefore, the beam changes significantly in the underfocus direction compared to the case without deflection. Since this electron beam is changed in the overfocus direction by the deflection magnetic field, it is focused on JAS 1 on screen 2. However, since the vertical diameter of the beam in the deflection magnetic field is significantly smaller than in the case without deflection, the amount of deflection aberration experienced by the beam is also reduced, and the beam is well focused even at a fairly large deflection angle.

〔Effect of the invention〕

As described above, according to the color picture tube device of the present invention, it is possible to obtain a good beam spot over the entire screen even at a considerably large deflection angle, thereby obtaining a color picture tube device with improved image performance. I can do it.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of the main parts of a color picture tube device embodying the present invention, FIGS. 2 to 4 are optical equivalent views of the Y-Z cross section of the electron gun section, and FIGS. 5 and 6 are The electrode voltage waveform given in the example, FIGS. 7 and 8 are schematic diagrams showing beam distortion due to deflection aberration, FIGS. 9 to 11 are front views of the electrode showing the electrode shape in the example, and FIG. 12 ( a) and FIG. 12(b) are schematic diagrams of screens for explaining the dynamic focus effect. Agent Patent Attorney Norihiro Chika Yudotake Hana Kikuo Diagram aspect ratio 4:3.110' In the case of deflection

Claims (1)

[Claims] (1) In a color picture tube device comprising an electron gun section, a deflection section, and a screen section, the electron beam emitted from the electron gun section is deflected and scanned in vertical and horizontal directions by the deflection section, wherein the electron gun section includes: An electron beam forming section including a cathode for generating, accelerating, and controlling an electron beam; and a main electron lens section for converging and concentrating the electron beam; and a second electron lens, the deflection in one direction by the deflection section is made up of at least first and second deflection regions, and the lens strength of the first electron lens is equal to the second electron lens.
A color picture tube device, characterized in that: the lens strength of the second electron lens changes depending on the amount of deflection of the second deflection region; and the lens strength of the second electron lens changes depending on the amount of deflection of the second deflection region.