JPH06318436A - Picture tube - Google Patents

Abstract

(57) [Abstract] [Purpose] To improve the withstand voltage characteristics without degrading the focus characteristics. A phosphor screen formed on an inner wall of a face plate portion, a cathode that emits an electron beam, a first grid electrode that controls the electron beam, a second grid electrode that accelerates the controlled electron beam, and the accelerated A main focusing lens forming grid electrode for focusing the electron beam is sequentially arranged in the emission direction of the electron beam, and an electron gun structure is provided on the neck portion of the grid electrode. In a picture tube having a grid electrode which has a symmetrical non-circular shape and has a taper formed all around the electron beam transmission hole, the taper is:
The widths from the edges of the transmission holes are all the same.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a picture tube, and more particularly to improvement of a grid electrode of an electron gun assembly of the picture tube.

[0002]

2. Description of the Related Art For example, in an electron gun assembly provided in a color picture tube, a cathode (cathode), a first grid electrode, a second grid electrode, a focus electrode, etc. are sequentially arranged on a central axis, and from this cathode Generated electron beam first
It is arranged so that it is guided to the side of the grid electrode or the second grid electrode, and the fluorescent screen is irradiated with light through the focus electrode or the like.

An electron beam transmission hole is formed in the grid electrode, and the transmission hole is usually circular, but in recent years, particularly rectangular ones have become known. .

This is because the rectangular shape having one side having the same length as the diameter of the circle makes it possible to increase the area of the transmission hole and improve the focus characteristic of the entire screen of the picture tube. is there.

Moreover, it has been known that a taper is provided all over the periphery of the transmission hole in order to improve the withstand voltage between other adjacent electrodes. By doing so, the electric field concentration at the edge of the transmission hole can be relaxed by forming the taper.

As such a technique, for example, JP-A-3-176930 and JP-A-3-179 are available.
It is described in detail in Japanese Patent No. 644, etc.

[0007]

In the case where the electron beam transmitting hole has a rectangular shape, it is necessary to provide R at the corner of the rectangular shape in order to manufacture the electron beam transmitting hole by press working with good productivity. Therefore, if a taper is simply formed around the rectangular electron beam transmitting hole, the taper shape state at the corner of the electron beam transmitting hole will be different from the taper shape state at the other side portions. .

For this reason, the electric field becomes nonuniform at the corners and other sides, which adversely affects the focus characteristics.

Therefore, the present invention provides a picture tube having an electron gun structure in which the electric field state around the electron beam transmission hole is made uniform in order to improve the withstand voltage characteristics without affecting the focus characteristics. is there.

[0010]

In order to achieve such an object, the present invention basically comprises the following means.

Means 1. A phosphor screen formed on the inner wall of the face plate, a cathode that emits an electron beam, a first grid electrode that controls the electron beam, a second grid electrode that accelerates the controlled electron beam, and the accelerated electron beam. A main focusing lens forming grid electrode for sequentially focusing in the electron beam emission direction, and an electron gun structure provided on the neck portion of the grid electrode. In a picture tube having a grid electrode having a circular shape and having a taper formed all around the electron beam transmission hole, the taper has the same width from the edge of the transmission hole. It is a thing.

Means 2. A picture tube comprising a phosphor screen formed on the inner wall of the face plate portion, a cathode for emitting an electron beam, and an electron gun assembly having a neck portion provided with a plurality of grid electrodes sequentially arranged in the electron beam emitting direction. In at least one of the grid electrodes, the electron beam transmission hole has a non-circular shape, and a taper is formed around the electron beam transmission hole, and the taper has a substantially rectangular outer edge. The radius of curvature of the corner portion of the taper outer edge portion is 0.05 mm or more.

[0013]

[Measures] 1. In the picture tube constructed as described above, in particular, in the taper formed around the electron beam transmission hole (non-circular) of the grid electrode, all widths in the radial direction from the edge of the transmission hole are the same. It has been formed in.

By doing so, the electric field state in the vicinity of the periphery of the electron beam through hole can be made uniform even in the vicinity of the electron beam through hole.

Therefore, the electric field state around the electron beam transmitting hole can be made uniform, and the withstand voltage characteristic can be improved without degrading the focus characteristic.

Further, the means 2. The picture tube constructed as described above does not necessarily have the above-mentioned means 1. as long as the corner portion of the outer edge portion of the Taber is provided. Even when the widths from the edges of the transmission holes are not all the same in the taper as described above, the same effect is obtained.

[0017]

FIG. 6 is a block diagram showing an embodiment of a color picture tube to which the electron gun assembly according to the present invention is applied.

In FIG. 1, there is a glass envelope 1, and a phosphor screen 3 is formed on the inner wall of a face plate portion 2 of the glass envelope 1.

This phosphor screen 3 has three colors (red, green, blue)
The phosphors are alternately applied in stripes.

An electron gun assembly 30 is arranged in the neck portion 20 of the glass envelope 1 so as to face the fluorescent screen 3.

This electron gun assembly 30 is for red, green,
It consists of each electron gun for blue.

The central electron gun among them is the cathode 7,
First grid electrode 9, second grid electrode 10, focusing grid electrode 11 and anode electrode 1 forming a main focusing lens
2. The shielding cups 13 are sequentially arranged with their central axes 16 aligned.

The same structure is adopted in the other electron guns on both sides, and the above-mentioned electrodes and the like are integrally formed with the electrodes having the same function of the other electron guns.

A voltage is applied to each of the electrodes and the cathodes 6, 7, and 8 which are integrally formed as described above via a stem pin, and such a voltage is applied to each of the cathodes 6, 7, and 8. An electron beam emitted from 8 is to be irradiated on the phosphor screen 3 with a predetermined beam diameter.

A shadow mask 4 is arranged on the side of the electron gun structure 30 of the fluorescent screen 3, and electron beams from the electron guns are focused on the surface of the shadow mask 4 and simultaneously overlap each other. Has become.

That is, each electron beam is adapted to be color-selected by the shadow mask 4, and only the component that excites and emits the phosphor of the color corresponding to each electron beam of the shadow mask 4. It reaches the phosphor screen 3 through the opening.

In order to scan the fluorescent screen 3 with such an electron beam, an external magnetic deflection yoke 14 is provided on a part of the outer surface of the glass envelope 1.

2A and 2B are detailed configuration diagrams showing an embodiment of the second grid electrode 10. FIG. 2A is a plan view and FIG. 2B is a sectional view taken along line IIb-IIb in FIG.

In the figure, there is a plate member 40 made of, for example, an Fe-Ni alloy, and three electron beam transmission holes 41A, 41B and 41C are formed in the plate member 40 at substantially the center thereof.
Are formed, and these electron beam transmission holes 41A, 41B,
41C has a substantially rectangular shape of the same shape and the same size, and are arranged side by side adjacent to each other.

The edge portions 46 of these electron beam transmitting holes are
If the corner portions of A, 46B, and 46C are not formed at right angles and are provided with a small radius of curvature, productivity in press working is improved and deformation of holes does not occur.

Each electron beam transmission hole 41A, 41
B and 41C are holes through which the red, green, and blue electron beams from the cathodes 6, 7, and 8 pass, respectively, and the taper 42A, 42 is formed in the entire peripheral area of these holes.
B and 42C are formed.

The tapers 42A, 42B and 42C will be described later with reference to FIG.

Each electron beam transmission hole 41A, 41B, 41
From the periphery of the plate material 40 which is parallel to the juxtaposed direction of C, a support part 43 is formed extending in a direction perpendicular to the juxtaposed direction, and the tip of this support part 43 is shown in FIG. It is designed to be embedded in a bead glass 44 not shown.

The bead glass 44 is a member for positioning and fixing each constituent member of the electron gun assembly 30 shown in FIG. 6 together with the second grid electrode 10, and is melted at the time of assembly and removed later. By inserting the rod member into the electron beam transmitting hole, it is pressed and fixed from both sides of the respective constituent members whose central axes are aligned with each other.

FIG. 1 is a detailed constitutional view showing an embodiment of the electron beam transmitting hole, (a) is a plan view and (b) is a sectional view taken along line Ib-Ib in (a).

In FIG. 3B, the taper 42A formed around the electron beam transmission hole 41A is, for example,
The diameter of the plate member 40 is gradually reduced from the surface of the plate member 40 to the inside of the plate member 40. The depth is 0.05 mm and the electron beam transmission hole 41A has the original diameter.

Further, the cross-sectional shape of the taper 42A in the electron beam traveling direction is substantially linear.

The tapered cross section may be curved.

Further, if the both ends of the tapered cross section, that is, the edge portion 46A of the electron beam transmission hole and the outer edge portion 47A of the taper are slightly curved, the electric field concentration at these edges can be alleviated and the withstand voltage characteristic between the electrodes can be improved. improves.

Then, as shown in FIG. 9A, the width of the taper 42A surrounding the electron beam transmission hole 41A is L at both the portion extending in the x direction and the portion extending in the y direction in the figure. In addition, the width at the corners is also L, for example. That is, the width in the radial direction from the center of the electron beam transmission hole 41A is all L.

In this case, the width in the radial direction from the center of the electron beam transmission hole 41A is not limited to L as long as the corner has a radius of curvature R.

As described above, the corner portion of the taper outer edge 47A does not have a right angle, and the radius of curvature R is taken. Therefore, the productivity in the press working is improved and the plate material 40 is not cracked at the corner portion. Further, by doing so, it is possible to make the taper width L from the electron beam transmitting hole substantially uniform.

Therefore, for example, the neck portion of the picture tube is φ2.
In the case of an electron gun structure of 9 mm, the length of one side of the electron beam transmission hole is 0.6 mm, the radius of curvature Ra of the corner portion of the electron beam transmission hole is 0.1 mm, and the pitch of each electron beam transmission hole is 5.5 mm. , The width L of the taper is 0.05 mm, and the radius of curvature R of the corner portion of the outer edge of the taper is 0.05 mm or more, the electron beam transmission holes 41A, 41B,
The electric field state in the vicinity of the periphery of 41C is almost uniform even in the vicinity of the corners of the electron beam transmission holes 41A, 41B, 41C, and does not adversely affect the focusing characteristics of the picture tube.

Further, it is preferable that the radius of curvature R of the corner portion of the taper outer edge portion is 0.10 mm or more.

Further, it has been found that when the radius of curvature R is 0.15 mm, it is extremely effective.

According to the above-described embodiment, in particular, by setting the radius of curvature R of the corner portion of the taper outer edge portion to be 0.05 mm or more, the electron beam transmission hole 41 of the grid electrode 10 can be obtained.
In the taper 42A, 42B, 42C respectively formed around A, 41B, 41C, the transmission holes 41A,
The widths L of the edges 41B, 41C from the edges 46A, 46B, 46C in the radial direction are substantially the same.

Therefore, the electron beam transmission holes 41A, 4A
The electric field conditions around 1B and 41C can be made uniform, and the withstand voltage characteristics can be improved without degrading the focus characteristics.

FIG. 3 shows another embodiment of the present invention in which recesses (slits) 45A, 45B and 45C are formed further on the phosphor screen side of the taper formed around the electron beam transmitting hole.

FIG. 7A is a view of the second grid electrode 10 'viewed from the phosphor screen side, and FIG. 9B is a sectional view taken along line IIIb-IIIb of FIG. 9A, showing slits 45A, 45B on the phosphor screen side.
45C is formed.

As a result, astigmatism can be formed and the deflection aberration by the deflection yoke 14 can be corrected.

FIG. 4 shows another embodiment of the present invention.
Recess (slit) 4 on the cathode side from the electron beam transmission hole
5A, 45B and 45C are formed.

FIG. 7A is a view of the second grid electrode 10 ″ viewed from the cathode side, and FIG. 8B is a sectional view taken along line IVb-IVb of FIG.
This is an example in which B and 45C are formed, whereby spherical aberration of prefocus can be reduced.

FIG. 5 shows still another embodiment of the present invention, in which the first grid electrode 9 has a taper formed around the electron beam transmission hole and a concave portion (slit) is formed on the fluorescent screen side. This is an example of application.

FIG. 7A is a view of the first grid electrode 9 seen from the phosphor screen side, and FIG. 9B is a sectional view taken along the line Vb-Vb of FIG. 9A, which shows slits 45 on the phosphor screen side of the first grid electrode 9.
This is an example in which A, 45B and 45C are formed, whereby spherical aberration of prefocus can be reduced.

It is needless to say that the present invention is not necessarily limited to the above-mentioned embodiments and can be applied to other grid electrodes.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the color picture tube which generates three electron beams has been described, but it is also applicable to the single electron gun type picture tube which generates one electron beam. Needless to say.

Furthermore, in the above embodiment, the taper is formed on the phosphor screen side of the electron beam transmission hole, but the present invention is not limited to this, and the taper is formed from the electron beam transmission hole to the cathode. It goes without saying that it may be formed on the side.

[0058]

As is apparent from the above description,
According to the picture tube of the present invention, the withstand voltage characteristic can be improved without degrading the focus characteristic.

[Brief description of drawings]

1A and 1B are detailed configuration diagrams of a main part showing a vicinity of an electron beam transmission hole of an embodiment of a second grid electrode of a color picture tube according to the present invention, and FIG. (B) is sectional drawing in the Ib-Ib line of (a).

2A and 2B are configuration diagrams showing an embodiment of a second grid electrode of the color picture tube according to the present invention.
Is a plan view and (b) is a sectional view taken along line IIb-IIb in (a).

3 (a) and 3 (b) are detailed configuration diagrams of essential parts showing the vicinity of electron beam transmission holes of another embodiment of the second grid electrode of the color picture tube according to the present invention, and FIG. 3 (a) is a plan view. , (B) are sectional views taken along line IIIb-IIIb in (a).

4 (a) and 4 (b) are detailed configuration diagrams of a main part showing the vicinity of an electron beam transmission hole of still another embodiment of the second grid electrode of the color picture tube according to the present invention, and FIG. Figure,
(B) is a sectional view taken along line IVb-IVb of (a).

5 (a) and 5 (b) are detailed configuration diagrams of a main part showing the vicinity of an electron beam transmission hole of an embodiment of the first grid electrode of the color picture tube according to the present invention, and FIG. (B) is a sectional view taken along the line Vb-Vb of (a).

FIG. 6 is a schematic configuration diagram showing an embodiment of a color picture tube according to the present invention.

[Explanation of symbols]

9 1st grid electrode 10 2nd grid electrode 40 Plate material 41A, 41B, 41C Electron beam penetration hole 42A, 42B, 42C taper 46A, 46B, 46C Electron beam penetration hole edge part 47A, 47B, 47C taper outer edge part R taper outer edge part Radius of curvature of the corner portion of Ra Ra radius of curvature of the corner portion of the electron beam transmission hole

Claims (16)

[Claims] 1. A phosphor screen formed on an inner wall of a face plate, a cathode for emitting an electron beam, a first grid electrode for controlling the electron beam, a second grid electrode for accelerating the controlled electron beam, and An electron gun structure in which a main focusing lens forming grid electrode for focusing the accelerated electron beam is sequentially arranged in the emission direction of the electron beam and provided in the neck portion, and the electron beam transmission hole of each of the grid electrodes is provided. In a picture tube including a grid electrode having a point-symmetrical non-circular shape and having a taper formed all over the periphery of the electron beam transmission hole, the taper has the same width from the edge of the transmission hole. A picture tube characterized in that. 2. A phosphor screen formed on the inner wall of the face plate portion, a cathode that emits an electron beam, a first grid electrode that controls this electron beam, a second grid electrode that accelerates this controlled electron beam, and this A picture tube comprising a main focusing lens forming grid electrode for focusing an accelerated electron beam, which is sequentially arranged in the emission direction of the electron beam, and an electron gun assembly provided at a neck portion, wherein at least one of the grid electrodes is provided. One is that the electron beam transmitting hole has a non-circular shape, and the electron beam transmitting hole has a taper in the periphery thereof, and the taper has a non-circular shape at its outer edge portion. A picture tube having a curved portion. 3. A phosphor screen formed on the inner wall of the face plate portion, a cathode that emits an electron beam, a first grid electrode that controls this electron beam, a second grid electrode that accelerates this controlled electron beam, and this. A picture tube comprising a main focusing lens forming grid electrode for focusing an accelerated electron beam, which is sequentially arranged in the emission direction of the electron beam, and an electron gun assembly provided at a neck portion, wherein at least one of the grid electrodes is provided. One is that the shape of the electron beam transmission hole is non-circular, and the periphery of the electron beam transmission hole has a taper, and the shape of the outer edge of the taper is substantially rectangular. A cathode ray tube having a corner portion having a finite radius of curvature. 4. The picture tube according to claim 3, wherein a radius of curvature of a corner portion of the tapered outer edge portion is set to 0.05 mm or more. 5. The picture tube according to claim 2, wherein said electron beam transmitting hole has a substantially rectangular shape, and its corner portion has a finite radius of curvature. 6. The picture tube according to claim 1, wherein the taper has a curved cross section in the electron beam emission direction. 7. The taper is characterized in that its cross section in the electron beam emission direction is substantially linear.
The picture tube according to any one of 1 to 3. 8. The picture tube according to claim 1, wherein the taper has a curved end portion in a cross section in the electron beam emission direction. 9. The taper is formed on the phosphor screen side of the second grid electrode.
The picture tube according to any one of 1 to 3. 10. The second grid electrode is formed with a single or a plurality of recesses for reducing the plate thickness, and the transmission hole and the tapered portion are formed in the recesses. The picture tube according to item 9. 11. The picture tube according to claim 10, wherein the recess is formed on the phosphor screen side. 12. The picture tube according to claim 10, wherein the recess is formed on the cathode side. 13. The picture tube according to claim 1, wherein the taper is formed on the phosphor screen side of the first grid electrode. 14. The first grid electrode is formed with a single or a plurality of recesses for reducing the plate thickness, and the transmission hole and the tapered portion are formed in the recesses. 13. The picture tube according to item 13. 15. A phosphor screen formed on an inner wall of a face plate portion, a cathode that emits an electron beam, a first grid electrode that controls the electron beam, a second grid electrode that accelerates the controlled electron beam, and the first grid electrode. A picture tube comprising a main focusing lens forming grid electrode for focusing an accelerated electron beam, which is sequentially arranged in the emission direction of the electron beam, and an electron gun assembly provided at a neck portion, wherein at least one of the grid electrodes is provided. One is that the electron beam transmission hole has a non-circular shape, and the electron beam transmission hole has a taper around its periphery, and the taper has a non-circular shape at its outer edge portion. A picture tube characterized in that the width on a plane perpendicular to the electron beam emission direction is almost the same. 16. A phosphor screen formed on an inner wall of a face plate, a cathode emitting an electron beam, a first grid electrode for controlling the electron beam, a second grid electrode for accelerating the controlled electron beam, and a second grid electrode for accelerating the controlled electron beam. A picture tube comprising a main focusing lens forming grid electrode for focusing an accelerated electron beam, which is sequentially arranged in the emission direction of the electron beam, and an electron gun assembly provided at a neck portion, wherein at least one of the grid electrodes is provided. One is that the electron beam transmitting hole has a substantially rectangular shape, and the electron beam transmitting hole has a taper in the periphery thereof, and the taper has a finite radius of curvature at the outer edge portion at the corner portion. It is substantially rectangular, and the width of the taper on a plane perpendicular to the electron beam emission direction is substantially the same at the side portion of the electron beam transmission hole. Picture tube according to.