KR20030028130A - Electron gun for color cathode ray tube - Google Patents

Abstract

PURPOSE: An electron gun for a color cathode ray tube is provided to achieve improved focus characteristics by improving the shape of electron beam emitted from the triode unit. CONSTITUTION: An electron gun comprises a cathode(10) serving as an electron beam emitter; a control electrode(20) having a third electron beam passing hole(21) for passage of electron beam emitted from the cathode; a screen electrode(30) arranged adjacent the control electrode, and which has a transversely elongated second inlet portion(32) and a rhombic second electron beam passing hole(31) formed at the electron beam incident side; one or more focusing electrodes(40) arranged in sequence from the screen electrode; and a final accelerating electrode arranged adjacent the focusing electrode, and which forms a main lens.

Description

Electron gun for color cathode ray tube

The present invention relates to an electron gun for a color cathode ray tube, and more particularly, to an electron gun for a color cathode ray tube having an improved structure of an electrode so as to improve focus characteristics.

A typical cathode ray tube employs a self-converging deflection yoke having an pincushion type deflection field and a barrel type deflection field and an inline electron gun. The deflection magnetic field of the double deflection yoke causes the electron beam to be vertically overfocused and horizontally underfocused to cause focus separation. Accordingly, the modified electron beam spot becomes asymmetric when deflected to the periphery of the screen. It may cause distortion. In addition, the in-line electron gun cannot obtain the uniformity of focus due to the change in the intensity of the electron lens generated by the change in the focus voltage.

In order to compensate for the distortion of the electron beam due to the non-uniform magnetic field of the deflection yoke, an electron gun having an elongated cross section of the electron beam landing at the periphery of the screen is disclosed in US Pat. No. 5,128,585.

The disclosed electron gun is made by forming an elongated inlet on the electron beam exit side and an elongated inlet on the electron beam exit side. The electron gun having such a control electrode compensates for the distortion of the electron beam at the periphery of the screen by moving the position of the cross-over point in the vertical direction than the horizontal direction to the screen side. However, this control electrode has a small diameter of the vertical electron beam passing through the rectangular electron beam through hole penetrated by the transverse and longitudinal inlets, causing interference with the mask, which serves as the color discrimination function of the electron beam during scanning. Will occur.

In addition, an electron gun for a color cathode ray tube having a control electrode having an elongated electron beam through hole and a screen electrode having an elongated electron beam through hole, and a focusing electrode facing the emission side of the screen electrode, is formed so that a circular electron beam through hole is formed. By minimizing the angle of incidence to the main lens formed by the focusing electrodes, the vertical focus uniformity is achieved by minimizing the spread of the electron beam spot landing on the periphery of the screen by the vertical deflection magnetic field of the deflection yoke. However, these electron guns have limitations on the screen of a very large or flat plane, and the vertical beam diameter of the electron beam in the center of the screen rapidly increases as the current increases due to the change of the spot of the electron beam sensitive to the amount of current change according to the magnitude of the video signal. It becomes large and the focus characteristic falls. In the case of the electron gun, when the current density of the electron beam is low, the electron beam diameter is small, and there is a problem in that moire is generated in the low luminance.

As described above, the electron gun has a quadrangular shape of an electron beam passing hole of an electrode, that is, a control electrode and a screen electrode, which forms a triode, and the shape of the beam is also close to a square. Therefore, when an electron beam close to the quadrangle enters the main lens, four vertices of the quadrangular electron beam are incident on the outer edge of the lens, which is affected by spherical aberration.

In addition, considering the case where the beam is incident on the periphery of the screen which is most affected by the deflection magnetic field of the deflection yoke, the combination of the pin magnetic field and the barrel magnetic field of the deflection yoke acts in the diagonal direction, and thus the rectangular cross section In the electron beam with, the spherical aberration is affected by the vertex of this rectangle, that is, the position where the electron beam is most widely spread, which worsens the focusing of the electron beam.

Furthermore, in the color cathode ray tube adopting the deflection yoke and the in-line type, the influence of this spherical aberration is inevitable due to structural reasons in which the size of the lens cannot be increased indefinitely, and the distortion of the electron beam due to non-uniform magnetic field is prevented. The phenomenon is inevitable.

The present inventors have attempted to improve the focus deterioration phenomenon by forming the shape of the electron beam as insensitive to such a phenomenon as possible if the above phenomenon cannot be completely eliminated.

In other words, the present invention is to solve the above problems, by modifying the shape of the electron beam emitted from the three poles can reduce the spherical aberration of the main lens and the divergence effect by the deflection yoke magnetic field to improve the focus characteristics The object is to provide an electron gun for a color cathode ray tube.

1 is a perspective view showing an electron gun for a color cathode ray tube according to an embodiment of the present invention.

2 and 3 are perspective views showing other embodiments of the electron gun for a color cathode ray tube according to the present invention having a screen electrode as shown in FIG.

Figure 4 is a perspective view showing an electron gun for a color cathode ray tube according to another preferred embodiment of the present invention

5 and 6 are perspective views showing other embodiments of the electron gun for color cathode ray tube according to the present invention having a screen electrode as shown in FIG.

7A and 7B are perspective views illustrating embodiments of a rhombus electron beam passing hole according to the present invention.

8 and 9 are views showing the shape of the electron beam according to an embodiment of the present invention and the shape of the electron beam according to a comparative example, respectively.

<Brief description of symbols for the main parts of the drawings>

10: cathode 20: control electrode

21: first electron beam passing through 22: first inlet

23: first electron beam through hole 30: screen electrode

31: second electron beam passing through 32: second inlet

33: first electron beam passing hole 40: focusing electrode

In order to achieve the above object, the present invention forms a three-pole portion, a control electrode formed with a cathode, a first electron beam passing hole for passing an electron beam emitted from the cathode, and installed adjacent to the control electrode, the electron beam is incident And a screen electrode on which a second inlet portion having a horizontal shape is formed and a second electron beam passing hole having a rhombus shape, and at least one focusing electrode sequentially installed from the screen electrode and adjacent to the focusing electrode. It provides an electron gun for a color cathode ray tube, characterized in that comprises a final acceleration electrode forming a lens.

According to another feature of the present invention, the first electron beam passing hole may have a circular or elongated rectangular shape, and the first electron beam passing hole has an elongated first inlet portion formed at the electron beam exit side, and has a rhombus shape. The first electron beam through hole of may be formed, wherein the first electron beam through hole of the rhombus shape may be formed to have a vertical width greater than the horizontal width.

According to another feature of the present invention, the second electron beam passing hole may be formed such that the vertical width is larger than the horizontal width.

In addition, the electron gun for the color cathode ray tube of the present invention for achieving the above object is installed adjacent to the control electrode, the control electrode is formed with a cathode, the electron beam emission source, the first electron beam passing hole to pass the electron beam emitted from the cathode And a screen electrode having a horizontally-shaped second inlet portion formed on the side from which the electron beam is emitted, and a second electron beam passing hole having a rhombus shape, and at least one focusing electrode sequentially installed from the screen electrode and adjacent to the focusing electrode. It is characterized in that it comprises a final acceleration electrode which is installed to form a main lens.

According to another feature of the present invention, in the electron gun as described above, the first electron beam passing hole may have a circular or elongated rectangular shape, and the first electron beam passing hole has a longitudinal first toward the electron beam exit side. An inlet may be formed, and the first electron beam through hole having a rhombus shape may be formed. In this case, the first electron beam through hole having a rhombus shape may be formed to have a vertical width greater than a horizontal width. The second electron beam passing hole may be formed to have a vertical width greater than a horizontal width.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the color cathode ray tube according to the present invention, the electron gun is installed at the neck portion of the cathode ray tube to emit an electron beam to excite the fluorescent film, and forms a cathode, a control electrode, a screen electrode, and an auxiliary and main lens forming the triode. It includes a plurality of focusing electrode and the final acceleration electrode.

1 is a view showing a triode forming an electron beam and forming a water point in an electron gun according to an exemplary embodiment of the present invention.

As shown in the drawing, the cathode 10 constituting the triode has an electron-emitting part impregnated or coated with an electron-emitting material at its front end and a heater for heating it to the rear of the electron-emitting part.

The first electron beam through hole 23 is formed at a position corresponding to the cathode 10 in the control electrode 20 provided adjacent to the cathode 10, and the screen electrode is adjacent to the control electrode 20. 30 and the focusing electrode 40 are disposed. All of these electrodes have electron beam passing holes 33 and 43 formed at positions corresponding to the cathode 10 and the first electron beam passing hole 23.

As shown in FIG. 1, the first electron beam through-hole 23 of the control electrode 20 is formed in a circular shape, and the second electron beam through-hole 33 formed in the screen electrode 30 is a horizontally-shaped side formed at an incident side thereof. 2nd lead-in part 32 of this, and the 2nd electron beam through-hole 31 of the rhombus shape formed in this 2nd lead-in part 32 is provided. In this case, the first electron beam through hole 23 formed in the control electrode 20 may be formed in a rectangular shape as shown in FIG. 2. The rectangular first electron beam through hole 23 is formed such that the width X1 in the vertical direction is larger than the width X2 in the horizontal direction, and the ratio is preferably such that X1: X2 is about 6: 5. . This length ratio may also be applied to the circular first electron beam through hole 23 as shown in FIG. 1 to form it as an elongated ellipse.

Also, as shown in FIG. 3, the first electron beam through hole 23 has an elongated first inlet 22 formed on the electron beam exit side of the control electrode 20, and the first inlet 22. It may be provided as a rhombus-shaped first electron beam through hole 21 formed in the inside.

As such, the shape of the electron beam through hole formed in the control electrode is not limited to the above-described embodiment, and may be modified in various forms for changing the cross section of the electron beam.

Meanwhile, a circular electron beam through hole 43 is formed in the focusing electrode 40 adjacent to the screen electrode, but any other shape may be used to improve focusing of the electron gun. The other focusing electrodes may have an electron lens and a quadrupole lens. Electron beam through holes may be formed.

Figure 4 shows the structure of the three-pole portion of the electron gun according to another embodiment of the present invention. The electron gun shown in the figure is to form the electron beam passing hole 33 of the screen electrode 30 toward the electron beam exit side in the electron gun as described in the above-described embodiment. In other words, the horizontally-shaped second lead-in portion 32 is formed on the emission side of the electron beam, and the second electron beam passage hole 31 having a rhombus shape is formed therein.

Thus, forming the second lead portion 32 of the screen electrode 30 to the electron beam exit side can be applied to a small cathode ray tube of low current, the second lead portion of the screen electrode 30 as in the above-described embodiment It is preferable to form 32 on the electron beam incidence side for a high current medium and large cathode ray tube.

Also in this embodiment, the electron beam through hole 23 of the control electrode 20 may be circular or elongated as shown in FIG. 4, and may have an elongated quadrangle as shown in FIG. 5. It may also be in the shape, and as shown in Fig. 6, it may be formed by the longitudinally-shaped first inlet 22 formed on the exit side and the first electron beam through hole 21 in the rhombus shape.

In addition, the description of the focusing electrodes is the same as in the above-described embodiment.

In the electron gun according to the present invention, the rhombus-shaped second electron beam through hole 31 formed in the screen electrode 30 and the rhombus shape of the control electrode 20 as in the embodiment shown in FIGS. 3 and 6. The first electron beam through hole 21 may be formed in an elongated shape, as shown in FIGS. 7A and 7B.

That is, the distance between the vertices L1 in the vertical direction is longer than the distance between the vertices L2 in the horizontal direction, and in this case, the ratio of L1: L2 is preferably about 6: 5.

In addition, the rhombus-shaped electron beam passing hole may preferably take a perfect rhombic shape as shown in FIG. 7A, but since the tip may be generated near each vertex of the rhombus when the mold is manufactured, slightly at the vertex of the rhombus as shown in FIG. 7B. The octagonal shape can be taken to be flat enough.

Referring to the operation of the electron gun for the color cathode ray tube according to the present invention configured as described above are as follows.

When a predetermined voltage is applied to each electrode constituting the electron gun, a cathode lens is formed between the control electrode 20 and the screen electrode 30. The control electrode 20 constituting the cathode lens has a stronger focusing force in the horizontal direction due to the elongated first electron beam passing hole 23 or the elongated first inlet 22. It will be located closer to the cathode 10 side.

A pre-focus lens is formed between the screen electrode 30 and the first focusing electrode 40. This prefocus lens has a stronger focusing force in the vertical direction due to the horizontally-shaped second inlet portion 32 formed in the screen electrode 30, and the beam is self-reduced due to the cross section of the beam reduced in the vertical direction. As a result, the vertical haze of the beam spot can be reduced when deflecting.

An auxiliary lens and at least one quadrupole lens may be formed from a rear end of the first focusing electrode 40, and a main lens for final focusing and acceleration of the electron beam immediately before the final acceleration electrode (not shown). ) Is formed.

The electron beam emitted from the cathode 10 is focused and accelerated while passing through the electron lens formed between each electrode, is deflected by a deflection yoke (not shown), and lands on the fluorescent film to excite the phosphor.

According to the electron gun according to the present invention, the electron beam passing holes of the control electrode and the screen electrode have a rhombus shape, so that the shape of the electron beam incident on the main lens can be a rhombus instead of a square.

8, the shape of the electron beam according to the exemplary embodiment of the present invention is close to a rhombus shape having vertices formed in the horizontal and vertical directions, and compares the conventional rectangular electron beam through-hole of FIG. The electron beam of the electron gun having the control electrode or the screen electrode provided is close to the distorted rectangle.

The shape of the electron beam greatly affects deflection yoke of the self-convergence method using a non-uniform magnetic field and distortion of the beam when incident on the main lens.

In other words, since the deflection effect of the deflection yoke acts in the diagonal direction at the periphery of the screen as shown in FIG. However, the rhombus electron beam of the present invention as shown in FIG. 8 is less affected by the deflection effect in the diagonal direction of the deflection yoke, thereby reducing the distortion of the beam.

In addition, even when the electron beam is incident on the main lens, the rectangular electron beam as shown in FIG. 9 has four vertex portions incident to the outside of the lens, and thus is more affected by spherical aberration, and as shown in FIG. By implementing a beam shape close to the shape of, it is possible to prevent a specific portion of the bundle of electron beams from being more affected by spherical aberration.

As described above, the electron gun for the color cathode ray tube according to the present invention changes the shape of the electron beam through-holes of the control electrode and the screen electrode forming the three-pole portion, thereby affecting the shape of the electron beam by the nonuniform magnetic field of the deflection yoke and the spherical aberration of the main lens. It may be less affected to minimize the distortion of the electron beam.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary, and those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Therefore, the true technical protection scope of the present invention will be defined by the technical spirit of the appended claims.

Claims (16)

A cathode which is an emission source of an electron beam; A control electrode in which a first electron beam passing hole is formed so that the electron beam emitted from the cathode passes; A screen electrode installed adjacent to the control electrode and provided with a second entry portion having a horizontal shape and a second electron beam passing hole having a rhombus shape to an incident side of the electron beam; At least one focusing electrode sequentially installed from the screen electrode; And Electron gun for a color cathode ray tube, characterized in that it comprises a final acceleration electrode is installed adjacent to the focusing electrode to form a main lens. The method of claim 1, The first electron beam passing hole is a color cathode ray tube electron gun, characterized in that made of a circular or longitudinal rectangular shape. The method of claim 1, The first electron beam passing hole is an electron gun for a color cathode ray tube, characterized in that consisting of the elongated first inlet portion formed on the electron beam exit side and the first electron beam through hole of the rhombus shape. The method of claim 3, wherein The first electron beam passing through the electron gun for a color cathode ray tube, characterized in that the vertical width is larger than the horizontal width. The method according to any one of claims 1 to 4, The electron beam gun for the color cathode ray tube, characterized in that the second electron beam passing through the vertical width is larger than the horizontal width. A cathode which is an emission source of an electron beam; A control electrode through which the electron beam emitted from the cathode passes, wherein a first electron beam passage hole is formed; A screen electrode installed adjacent to the control electrode and provided with an elongated second lead-in portion and a rhombus-shaped second electron beam passing hole toward an electron beam exiting side; At least one focusing electrode sequentially installed from the screen electrode; And Electron gun for a color cathode ray tube, characterized in that it comprises a final acceleration electrode is installed adjacent to the focusing electrode to form a main lens. The method of claim 6, The first electron beam passing hole is a color cathode ray tube electron gun, characterized in that made of a circular or longitudinal rectangular shape. The method of claim 6, The first electron beam passing hole is an electron gun for a color cathode ray tube, characterized in that consisting of the elongated first inlet portion formed on the electron beam exit side and the first electron beam through hole of the rhombus shape. The method of claim 8, The first electron beam passing through the electron gun for a color cathode ray tube, characterized in that the vertical width is larger than the horizontal width. The method according to any one of claims 6 to 9, The electron beam gun for the color cathode ray tube, characterized in that the second electron beam passing through the vertical width is larger than the horizontal width. A cathode which is an emission source of an electron beam; A control electrode through which the electron beam emitted from the cathode passes, the elongated first inlet portion and a rhombus-shaped first electron beam passage hole provided to the electron beam exiting side; A screen electrode installed adjacent to the control electrode and provided with a second insertion portion having a horizontal shape and a second electron beam passing hole having a rhombus shape toward an electron beam incident side; At least one focusing electrode sequentially installed from the screen electrode; And Electron gun for a color cathode ray tube, characterized in that it comprises a final acceleration electrode is installed adjacent to the focusing electrode to form a main lens. The method of claim 11, The first electron beam passing through the electron gun for a color cathode ray tube, characterized in that the vertical width is larger than the horizontal width. The method of claim 11 or 12, The electron beam gun for the color cathode ray tube, characterized in that the second electron beam passing through the vertical width is larger than the horizontal width. A cathode which is an emission source of an electron beam; A control electrode through which the electron beam emitted from the cathode passes, the elongated first inlet portion and a rhombus-shaped first electron beam passage hole provided to the electron beam exiting side; A screen electrode installed adjacent to the control electrode and provided with an elongated second lead-in portion and a rhombus-shaped second electron beam passing hole toward an electron beam exiting side; At least one focusing electrode sequentially installed from the screen electrode; And Electron gun for a color cathode ray tube, characterized in that it comprises a final acceleration electrode is installed adjacent to the focusing electrode to form a main lens. The method of claim 14, The first electron beam passing through the electron gun for a color cathode ray tube, characterized in that the vertical width is larger than the horizontal width. The method according to claim 14 or 15, The electron beam gun for the color cathode ray tube, characterized in that the second electron beam passing through the vertical width is larger than the horizontal width.