JPH067144U - Inline electron gun - Google Patents

Abstract

(57) [Abstract] [Purpose] To eliminate the difference in focus voltage and electron beam spot diameter caused by the prefocus lens system. A unipotential prefocus lens having a bipotential type main electron lens system and a hole spacing portion in which a central electrode potential is lower than both end electrodes and a part of electrode holes at both ends of the center electrode are smaller than a hole spacing between facing electrodes. In an in-line type electron gun having a system, the central electrode hole of the fourth electrode is made larger in diameter than the electrode holes at both ends. [Effect] The strength of the prefocus lens system formed in each of the electrode holes 1, 2, and 3 becomes the same. Thus, the positions of the virtual object points viewed from the main lens system are the same, and there is no difference in beam spot diameter and focus voltage on the screen, and good resolution can be obtained.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to an in-line type electron gun used for a color cathode ray tube.

[0002]

[Prior art]

FIG. 8 is a cross-sectional view of a cathode ray tube using an in-line type electron gun. 19 is a cathode ray tube frame, 20 is a shadow mask, 21 is a screen, and 22a and 22b are electron beams emitted from both ends of the inline type electron gun. , 23 are electron beams emitted from the central electron gun. FIG. 7 is a view showing the structure of a conventional in-line type electron gun. In the figure, 9 is a cathode, 8 is a heater, 10 is a first electrode, 11 is a second electrode, 12 is a third electrode, and 13 is a third electrode. 4 electrode (center electrode), 14 is the fifth _first electrode, 15 a fifth _second electrode (focus electrodes), the 16 sixth electrode, 17a, 17b are Bidogara scan for supporting the electrode. First electrode 10, second electrode 11, third electrode 12, fourth electrode 13, fifth _first electrode 14, the fifth _second electrode 15, to each of the sixth electrode 16 holes three electron beams pass Three are in one row. FIG. 5 shows a front view of the fourth electrode 13 as viewed in the direction of the arrow V in FIG. In this figure, 1, 2 and 3 are holes (electrode holes) through which the electron beam passes. FIG. 6 shows a cross-sectional view of the fourth electrode 13 seen from cross-sectional arrows VIa (VIb) and VI in FIG. 5, respectively. The fourth electrode 13 includes a fourth electrode 6 having holes 1, 2, and 3 having the same diameter, a _second electrode 6 having holes 1 and 3 having a diameter larger than that of holes 2, and a central axis of holes 1 and 2 and holes 3 and 2. intervals and a fourth _first electrode 5 which is narrower than that of the fourth _second electrode 6.

Next, the operation will be described. In the electron gun having the above-mentioned structure, normally, the potential of the first electrode 10 is used as a reference, the cathode 9 has a voltage of about 0 to 200 V, the second electrode 11 and the fourth electrode 13 have a voltage of about 100 to 1500 V, and the sixth electrode 16 has about 20000～35000V, third electrode 12, the fifth _first electrode 14, the fifth _second electrode 15 is under the potential of the order of 20% to 35% of the potential of the sixth electrode 16. At this time the fifth _first electrode 14 and the third electrode 12 is always the same potential. An electron beam is generated from the cathode 9 excited by the heater 8 and accelerated and shaped by the potential distribution constituted by the cathode 9, the first electrode 10 and the second electrode 11, and the third electrode 12 and the fourth electrode 13 are formed. , The bi-potential main focus generated by the 5 _2nd electrode 15 and the 6th electrode 16 after the electron beam has been narrowed down to some extent by the unipotential type prefocus lens system composed of the 5 _1st electrode 14. An electron beam is focused on the screen 21 by the electron lens system. In this case the three electron beams 22 a on the screen 21, 22b, 23 a in order to facilitate the focused at one point, advance the sixth electrode 16, the electron beam by the configured main electron lens system by the fifth _second electrode 15 The structure is such that 22a and 22b are brought closer to the electron beam 23 side (to take static convergence). In such an arrangement, it is necessary to design the pre-focus lens system so as to cancel the static convergence change due the potential fluctuation of the fifth _second electrode 15 of the main electron lens system. This, in one example is a child in a part eccentric structure as shown in FIGS. 5 and 6 the fourth electrode 13, is previously decentered prefocus lens, the third electrode being synchronized thereto and the 5 _second electrode 15 electron beam 22a in the direction opposite to the static convergence is changes in the main electron lens system when the potential of 12 is changed, if to change the 22b, static by the potential of the fifth _second electrode 15 on subscription over emissions 21 The change in convergence can be suppressed to a level where there is no practical problem.

[0004]

[Problems to be solved by the device]

Since the conventional prefocus lens system is configured as described above, the unipotential lens formed in the hole 2 is stronger than the unipotential lens formed in the holes 1 and 3. As a result, the virtual object point position viewed from the main electron lens system, which should be the same, is different between the electron beams 22a, 22b, and 23 as shown in 22c and 23c in FIG. 21 and the fifth _second electrode potential for focusing on (focus voltage), there is a problem that the electron beam spot size that can be on the screen 21 causes deterioration in the image quality of different color cathode ray tube with an electron beam 22a · 22b and 23 It was

The present invention has been made to solve the above-mentioned problems. The strength of the prefocus lens system is the same for all three holes, and the focus voltage generated by the prefocus lens system is reduced. The purpose is to eliminate the difference and the difference in electron beam spot diameter.

[0006]

[Means for Solving the Problems]

 The hole shape of the fourth electrode 13 of claim 1 according to the present invention has the same diameter as that of the fourth electrode. ₂ The hole diameter of hole 1 / hole 2 / hole 3 of electrode 6 is made larger than the hole diameter of hole 1 / hole 3 (both ends) so that the strength of the 3 holes of the prefocus lens is the same. It is

According to the second aspect of the present invention, the hole shape of the fourth electrode 13 is the same as that of the fourth electrode. ₂ Hole 1, hole 2, hole 3 and fourth of electrode 6₁ Regarding the hole diameter of the hole 2 of the electrode 5,₁ Electrode 5 and 4₂ The hole diameter of the hole 2 of the electrode 6 is₂ It is made larger than the hole diameters of the holes 1 and 3 of the electrode 6 to make the strength of the three holes of the prefocus lens the same.

[0008]

[Action]

The action in invention is the fifth _first electrode 14, the fourth electrode 13 are formed by holes in the third electrode 12 Noso respectively, with respect to the electron beam 22a · 22b · 23, the strength of the flop refocusing lens system By making the same, the position of the virtual object point seen from the main lens diameter is made the same, and there is no difference in beam spot diameter and focus voltage on the screen, and good image quality is obtained.

[0009]

【Example】

Example 1. An embodiment of this invention will be described below with reference to FIGS. 1 is a front view of a fourth electrode according to the present invention, and FIG. 2 is a cross-sectional view of cross-sectional arrows IIa (IIb) and II in FIG. In the figure, 13 is a fourth electrode, and 1, 2 and 3 are holes through which electron beams pass. 5 the fourth _first electrode, 6 is a fourth _second electrode. The diameter of the hole 2 at the center of the 4 _2nd electrode 6 is larger than the diameter of the holes 1 and 3 on both sides (that is, it has a recess).

As a result, in the unipotential prefocus lens system formed by the third electrode 12, the fourth electrode 13, and the 5 ₁ electrode 14, the hole diameter of the 5 ₂ electrode 5 and the hole diameter of the hole 3 are 2 The difference in the strength of the electron lens due to the larger hole diameter can be canceled by increasing the hole diameter of the hole 2 of the 4 _{2 2nd} electrode 6, and the same lens strength can be obtained. As a result, the difference between the beam spot diameters of the electron beams 22a, 22b and 23 on the screen 21 caused by the difference in the strength of the prefocus lens system is eliminated, and the electron beam 2 caused by the same cause is eliminated. It is also possible to eliminate the difference in focus voltage between 2a, 22b and 23. As a result, the deterioration of the image quality on the screen caused by the difference in the strength of the prefocus lens system is eliminated.

Example 2. In the first embodiment, the fourth electrode 13 is composed of two parts, the 4 ₂ electrode 5 and the 4 ₂ electrode 6, but the same shape is formed by one part by press molding or the like. Even if it has the same effect.

Example 3. Another embodiment of the present invention will be described below with reference to FIGS. FIG. 3 is a front view of a fourth electrode according to the present invention, and FIG. 4 is a cross-sectional view of cross-section arrows IVa, IVb and IV in FIG. In the figure, 13 is a fourth electrode, and 1, 2 and 3 are holes through which an electron beam passes. 5 the fourth _first electrode, 6 is a fourth _second electrode. Diameter of the hole 2 of the fourth _{and second} electrodes 6 is larger than the diameter of the hole 1-hole 3. At the same time the hole diameter of the hole 2 of the 4 _first electrode 5 also it is in the same diameter as the fourth _second electrode 6, a pore size Example 1 because of the effect of higher if it increases only the fourth _second electrode hole It can be made smaller than those of (1) and (2).

Example 4. In the third embodiment, the fourth electrode 13 is composed of two parts, that is, the 4 _1st electrode 5 and the 4 _2nd electrode 6, but one part forms the same shape by press molding or the like. Even if it has the same effect.

[0014]

[Effect of device]

 As described above, according to the present invention, the unipotential type prefocus lens formed in the hole 2 of the fourth electrode 13 has the same strength as that formed in the holes 1 and 3. Since the hole diameter of No. 2 is increased, there is an effect of eliminating the difference in beam spot diameter on the screen and the difference in focus voltage due to the imbalance of the strength of the prefocus lens system.

[Brief description of drawings]

FIG. 1 is a front view of a fourth electrode 13 according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view of hole 1, hole 3 and hole 2 of a fourth electrode 13 of FIG.

FIG. 3 is a front view of a fourth electrode 13 according to another embodiment of the present invention.

4 is a cross-sectional view of hole 1 / hole 3 and hole 2 of the fourth electrode 13 of FIG.

FIG. 5 is a front view of a conventional fourth electrode 13.

6 is a cross-sectional view of hole 1, hole 3 and hole 2 of the fourth electrode 13 of FIG.

FIG. 7 is an electrode configuration diagram of a general in-line type electron gun.

FIG. 8 is a cross-sectional view of a general in-line type color cathode ray tube.

FIG. 9 is a principle diagram of an electron lens system.

[Explanation of symbols]

1 Electrode hole at the side edge of the central electrode (4th electrode) 2 Electrode hole at the center of the central electrode (4th electrode) 3 Electrode hole at the side edge of the central electrode (4th electrode) 5 Hole smaller than the hole interval between the facing electrodes the fourth electrode 14 unipotential prefocus lens constituting the fourth _first electrode 6 4 ₁ third electrode 13 unipotential prefocus lens system constituting the first face and the electrode 4 ₂ electrode 12 unipotential prefocus lens system having a spacing 5 ₁ electrode forming the system 15 5 ₂ electrode forming the main electron lens system 16 6th electrode forming the main electron lens system

Claims (2)

[Scope of utility model registration request] 1. The potential of the center electrode of the prefocus lens system is set lower than the potential of the electrodes at both ends of the prefocus lens system, and a part of the electrode holes at both ends of the three electrode holes in the center electrode is provided. It has a unipotential type prefocus lens system having a hole spacing portion smaller than the hole spacing of the electrodes facing each other, and a main electron lens system, and the central electrode hole of the central electrode of the prefocus lens system is larger than the electrode hole diameters at both ends. An in-line type electron gun characterized by having a recess. 2. An electrode in which the potential of the center electrode of the prefocus lens system is set lower than the electrode potential of both ends of the prefocus lens system, and a part of the electrode holes at both ends of the three electrode holes in the center electrode face each other. It has a unipotential type prefocus lens system having a hole spacing portion smaller than the hole spacing of, and a main electron lens system, and that the central electrode hole of the central electrode of the prefocus lens system is larger than the electrode holes at both ends. Characteristic in-line type electron gun.