KR100302155B1 - Method for manufacturing cathode ray tube and electron gun using electron gun and electron gun - Google Patents

Abstract

An object of the present invention is to provide a cathode ray tube which displays an image whose time is stable in brightness at high resolution. Electron guns 2a, 2b, 2c provided in the cathode ray tube of the present invention were composed of electrostatic lenses 5a, 5b, 5c, electron beam forming portion 9, and the like. The electrostatic lens was formed of a tubular substrate 6 and a beam spot. The resistive structures 7a, 7b, 7c and the resistive structures formed on the tubular substrate are manufactured by a manufacturing method of searching for a resistance distribution that minimizes the coefficient C and also minimizes the beam spot coefficient Cm. Electrical connections 8a, 8b, 8c and the like for applying a constant voltage.

Description

Method for manufacturing cathode ray tube and electron gun using electron gun and electron gun

The present invention relates to a cathode ray tube used for a color television receiver and the like and an electron gun used for the cathode ray tube.

In recent years, the development of the projection type television receiver using a cathode ray tube is thriving as a large-screen, high-resolution television receiver.

Known forms of focusing electron beams of electron guns installed on cathode ray tubes include electrostatic lenses and magnetic lenses. In order to achieve high resolution, it is necessary to reduce the spherical aberration of the electrostatic lens or the magnetic lens. In general, when the lens diameter is increased, spherical aberration can be reduced.

In the case of the electrostatic lens, the maximum diameter is limited by the diameter of the neck portion of the cathode ray tube. This limitation does not apply to magnetic lenses, but magnetic lenses are not useful because of their high power consumption and weight. As a configuration for reducing spherical aberration of the electrostatic lens, without being limited to the diameter of the neck portion, for example, US Patent No. 3143681, as the electrostatic lens is provided with a resistive structure having a spiral pattern, effectively the neck portion A cathode ray tube with an enlarged diameter is disclosed.

Further, Japanese Patent Laid-Open No. 63-225464 discloses a structure of an electrostatic lens bearing a resistive structure formed by alternately disposing several spiral segments and several intermediate segments.

As a method for determining the length of the propagation direction of the electron beam of these spiral segments and the intermediate segment, it is described in the paper published in 1986, published in Optik, No. 4, Nos. 134 to 136. . This paper discloses that the minimum diameter of spots formed on the screen is proportional to the quarter power of the minimum value CO of the beam spot coefficient (C) shown in Eq. (2). The spherical aberration Cs of the electrostatic lens used in the calculation of Eq. (2) is calculated from the integral in the z-axis direction, which is the traveling direction of the electron beam, based on (Eq. 4).

Here, VO is the incident side voltage, zO is the z coordinate of the electro-optical object point at which the electron beam is generated, zs is the image point, i.e., the z coordinate of the screen on which the spot is formed, r is Radius of the paraxial orbit of an electron beam emitted at an angle of 1 radian from an object point, V is the potential distribution on the central axis of the coronal substrate, and V ', V ", V"' are one and two times of V respectively. , Three different derivatives are shown. These calculations are performed by computer simulation or the like, and the length of several cylindrical membrane portions and the length of several spiral portions are repeatedly calculated so that the beam spot coefficient C represented by Equation 2 becomes the minimum value CO.

Further, Japanese Patent Laid-Open No. 7-73818 discloses an electron gun which forms a unipotential electrostatic lens having the same configuration as the electron gun described above and having the same incident side voltage VO and the exit side voltage Vs.

In such a conventional cathode ray tube, when a predetermined voltage is applied to the resistance structure portion to operate, the spot diameter formed on the screen cannot be made sufficiently small, resulting in a result different from computer simulation. According to the conventional manufacturing method, an error of about 10 to 20% occurred with respect to the spot diameter characteristic of the cathode ray tube.

Moreover, when the amount of electric current supplied to an electron gun was made large, it turned out that the spot diameter changes with time. As the spot diameter fluctuates in time, the brightness of the displayed image becomes unstable in time.

An object of the present invention is to provide a cathode ray tube which displays an image having a stable time in brightness at a high resolution.

1 is a cross-sectional view of an electron gun according to a first embodiment of the present invention.

2 is a cross-sectional view of a cathode ray tube using an electron gun according to a first embodiment of the present invention.

3 is a flow chart of the manufacturing method of the present invention.

4 is a flowchart of a method of optimizing the focusing voltage Vf and calculating the beam spot coefficient C. FIG.

5 is an explanatory diagram showing a method for calculating the magnification M of an electrostatic lens.

6 is a graph showing the relationship between parameter (a) and electrostatic lens magnification (Mm).

7 is a graph showing the relationship between the parameter (a) and the spot diameter.

8 is a graph showing the relationship between the position of the main plane of the electrostatic lens and the focusing voltage Vf.

9 is a sectional view of an electron gun according to a second embodiment of the present invention.

10 is a graph showing the relationship between the ratio of the emission-side film thickness to the average film thickness and the focusing voltage Vf.

11 is a process explanatory diagram of a resistance structure part according to a second embodiment of the present invention.

12 is a sectional view of an electron gun according to a third embodiment of the present invention.

13 is an explanatory diagram of the electric field strength EO near the spiral portion and the electric field strength E near the center of the spiral portion.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, the manufacturing method of the electron gun which concerns on the 1st aspect of this invention selects a 2nd resistance value distribution from a 1st resistance value distribution, and the spherical aberration coefficient in the said 2nd resistance value distribution, and the magnification of an electrostatic lens. If the first beam spot coefficient obtained by determining or not satisfies a predetermined condition is not satisfied, the minimum value of the first beam spot coefficient is returned by returning the second resistance distribution as the first resistance distribution. A predetermined loop is applied to a first loop for searching for a distribution of the second resistance value that gives a value, to an aberration-independent function that depends on the magnification of the electrostatic lens and does not depend on the spherical aberration coefficient, and the minimum value of the first beam spot coefficient; If the second beam spot coefficient obtained according to the determination whether the predetermined condition is satisfied or not is satisfied, the second resistance value And a second loop for searching for a most suitable resistance value distribution giving a minimum value of the second beam spot coefficient as the distribution is returned to the first loop as the first resistance value distribution.

According to the above invention, an electron gun can be manufactured which makes the spot diameter of the electron beam small.

Moreover, in the manufacturing method of the electron gun which concerns on the 2nd aspect of this invention, in the said 1st aspect, the said 1st beam spot coefficient is a spherical aberration coefficient obtained by (Equation 4), and (Equation 5). By substituting the magnification of the electrostatic lens and the like into (Equation 2), the second beam spot coefficient is obtained by substituting the minimum of the magnification of the electrostatic lens and the first beam spot coefficient and so on (Equation 3). The aberration independent function and the first beam spot coefficient and the like can be obtained by substituting (Equation 1).

According to the above invention, an electron gun can be manufactured which makes the spot diameter of the electron beam small.

Moreover, the manufacturing method of the electron gun which concerns on the 3rd aspect of this invention WHEREIN: The said 1st or 2nd aspect WHEREIN: The resistance structure part is comprised from the resistive film formed in the inner wall of a tubular board | substrate, and the said resistive film set up the said tubular board | substrate. It is characterized in that formed in the state.

According to the above invention, the electron gun can be manufactured by a simple method with an electron gun having a small time variation in the spot diameter of the electron beam.

In the first or second aspect, the method for manufacturing an electron gun according to the fourth aspect of the present invention is the spiral portion closest to the exit side of the electron beam among the various spiral portions in which the resistance structure portion is formed on the inner wall of the tubular substrate. The length Ls is formed to be equal to or less than the inner diameter D of the tubular substrate.

According to the above invention, the electron gun can be manufactured by a simple method with an electron gun having a small time variation in the spot diameter of the electron beam.

Moreover, the electron gun which concerns on the 5th aspect of this invention is an electron gun provided with the electron beam forming part which generate | occur | produces an electron beam, the electrostatic lens etc. which focus an electron beam, An electrostatic lens is a tubular board | substrate, and the manufacturing method of this invention. And a resistance structure portion having a resistance distribution obtained by the above, and an electrical connection portion for applying a predetermined voltage to the resistance structure portion formed on the tubular substrate.

According to the said invention, the electron gun which makes the spot diameter of an electron beam small can be provided.

In addition, the cathode ray tube according to the sixth aspect of the present invention is a cathode ray tube having at least one electron gun for generating and converging an electron beam in a vacuum vessel, a screen for emitting light according to the beam of the electron beam, etc. This is an electron gun according to the fifth aspect.

According to the above invention, a cathode ray tube displaying a high resolution image can be provided.

The electron gun according to the seventh aspect of the present invention is an electron gun including an electron beam forming unit for generating an electron beam, an electrostatic lens for focusing the electron beam, etc., wherein the electrostatic lens includes a tubular substrate and an emission side of the electron beam. And a resistance structure portion composed of a resistive film whose resistance value is higher than the average of the overall resistance values, and an electrical connection portion for applying a predetermined voltage to the resistance structure portion provided on the tubular substrate.

According to the above invention, it is possible to provide an electron gun which reduces the time variation of the spot diameter of the electron beam.

In the electron gun according to the eighth aspect of the present invention, in the seventh aspect, the resistor film is characterized in that the film thickness on the emission side of the electron beam is thinner than the average of the total film thicknesses.

According to the above invention, an electron gun can be manufactured by a simple method using an electron gun having a small time variation in the spot diameter of the electron beam.

The electron gun according to the eighth aspect of the present invention is an electron gun including an electron beam forming portion for generating an electron beam, an electrostatic lens for focusing the electron beam, etc., wherein the electrostatic lens includes a tubular substrate and several cylindrical membrane portions. And a plurality of spiral parts are alternately arranged. Among the spiral parts, a resistance structure part having a length Ls closest to the emission side of the electron beam at or below the inner diameter D of the inertial board, and a resistance structure part installed on the tubular board. And an electrical connection portion for applying a predetermined voltage to the apparatus.

According to the above invention, it is possible to provide an electron gun which reduces the time variation of the spot diameter of the electron beam.

A cathode ray tube according to a tenth aspect of the present invention is a cathode ray tube having at least one electron gun for generating and connecting an electron beam, a screen for emitting light by beaming the electron beam, etc. An electron gun according to the aspect of the seventh, eighth or ninth aspect.

According to the above invention, it is possible to provide a cathode ray tube displaying an image whose brightness is stable in time.

Best Mode for Carrying Out the Invention Embodiments of the present invention will be described below with reference to the drawings.

1 is a block diagram showing an outline of an electron gun in the first embodiment of the present invention.

In FIG. 1, the electron gun 2a is comprised from the electrostatic lens 5a, the electron beam formation part 9, etc. In FIG. The electrostatic lens 5a consists of the tubular board 6, the resistance structure part 7a, the electrical connection parts 8a, 8b, 8c, etc., and has the main plane 25 in the z-axis direction (z = z25). Have

The electrical connection parts 8a and 8b are provided in the both ends of the tubular board | substrate 6 perpendicular | vertical to the z-axis, and are the thin-walled metal plate which provided the opening part in the center part, and are electrically connected by the lead wire 17. As shown in FIG. The electrical connection part 8c as a metal link is provided in the center of the resistance structure part 7a, and is electrically connected with the outside through the hole provided in the side wall of the tubular board | substrate 6. As shown in FIG.

The electron beam forming unit 9 is composed of a heater 9a, an electron source 9b, control electrodes 9c, 9d, 9e, a cylindrical electrode 9f, and the like. The control electrodes 9c, 9d and 9e are installed perpendicular to the z-axis and are thin walled metal plates with openings in the center. The cylindrical electrode 9f is a metal cylinder.

The tubular board | substrate 6 is a cylindrical board | substrate which has electrical insulation, such as a glass plate, for example. The resistive structure 7a formed on the inner wall of the tubular substrate 6 is made of a high resistance RuO 2-glass paste film having a sheet resistance of 5 MΩ, and cylindrical membrane portions 10a, 10b, 10c, 10d, which are cylindrical resistive films. 10e, 10f, 10g), and spiral portions 11a, 11b, 11c, 11d, 11e, 11f, etc. made of a resistive film having a predetermined spiral pattern.

The spiral portions 11a to 11f have the same pitch, and each has a predetermined length A1 to A6 in the z-axis direction, and the cylindrical membrane portions 10a to 10g each have a predetermined length B1 in the z-axis direction. To B7), the resistive structure 7a has the most suitable resistance value distribution Rzm depending on the spiral pattern. Hereinafter, for the sake of simplicity, the length in the z-axis direction is simply expressed as length.

When the incidence side voltage VO, the output side voltage Vs, and the focusing voltage Vf of the electron beam are respectively applied to the electrical connections 8a, 8b, and 8c, the spiral parts 11a to 11f function as voltage dividers. Inside the electrostatic lens part 5a, the potential distribution Vz corresponding to the resistance value distribution Rzm is generated on the central axis of the tubular substrate 6.

2 is a cross-sectional view showing the basic structure of a cathode ray tube using the electron gun 2a.

In FIG. 2, the vacuum container 1 is comprised from the optically transparent face plate 1a, the cone part 1b, the neck part 1c, etc. As shown in FIG. The screen 4 made of the phosphor film is formed on the inner wall of the face plate 1a. A conductor layer (not shown) was formed on the inner wall of the cone portion 1b and the screen 4, and is electrically connected to the outside by an anode button (not shown) provided on the cone portion 1b.

The magnetic deflection yoke 19 is attached to the outer surface near the connection portion of the neck 1c and the cone 1b. The end cap 20 is welded to the neck portion 1c and includes a pin 21 for electrically connecting the electron gun 2a and an external circuit. The electron gun 2a is attached in the substantially same axial shape with respect to the neck part 1c.

Hereinafter, the operation of the cathode ray tube of the present invention will be described.

A predetermined voltage is applied to the pin 21, and a screen voltage of, for example, 30 kV is applied to the conductor layer (not shown) formed on the screen 4. When the electron beam 3 generated and focused by the electron gun 2a shines on the screen 4, a spot 18 is formed on the screen 4 by the emission of the phosphor film. Furthermore, in this embodiment, the screen voltage is equal to the emission side voltage Vs by the lead wire 17.

The magnetic deflection yoke 19 controls the magnetic field generated in the x-axis direction in the horizontal direction and the y-axis direction in the vertical direction, thereby deflecting the electron beam 3 to change the position of the spot 18. Further, by controlling the beam current amount of the electron beam 3 generated by the electron gun 2a, the spot diameter of the electron beam 3 can be controlled to obtain a spot of desired brightness. In this way, the desired image can be displayed on the screen 4.

Here, the manufacturing method of the most suitable resistance value distribution Rzm which is a characteristic of this invention is demonstrated using drawing.

3 is a flowchart showing a manufacturing method of the present invention. In step S1, the distance P from the electro-optical object point z = zO to the main plane 25 of the electrostatic lens, the distance Q from the main plane 25 of the electrostatic lens to the image point, The incident side voltage VO, the exit side voltage Vs, the focusing voltage Vf, the length Lg of the glass tube, and the total number n of the spiral parts are provided. In the present embodiment, the emission side voltage Vs and the incident side voltage VO are the same. Moreover, parameter a is set to 0.2. The parameter (a) will be described later.

In step S2, the lengths B1 to Bn + 1 of the cylindrical membrane portions and the lengths A1 to An of the spiral portions are selected. In step S3, the resistance value distribution Rz of the resistance structure 7a is calculated from the length of the cylindrical membrane portion, the spiral length, and the like.

In step S4, the resistance value distribution Rz obtained in step S3 is used to optimize the focusing voltage Vf and calculate the beam spot coefficient C at that time. The processing of step S4 can be specifically performed by the flowchart shown in FIG.

In step S41, the focusing voltage Vf is selected, and in step S42, the potential distribution V (z) in the z-axis direction from the resistance value distribution Rz and the voltages VO, Vs, Vf and the like. Is calculated.

In step S43, the spherical aberration coefficient Cs can be obtained by calculating the potential distribution V (z) as shown in Eq. (4).

In addition, the magnification M of the electrostatic lens 5a is the paraxial orbit of the electron beam emitted at an angle of 1 radian from the electro-optical object point z = zO as shown in FIG. The inclination r '(zs) in the image definition (z = zs) of (31) can be calculated, and this slope r' (zs) can be calculated by substituting into (Equation 5).

The calculation method of magnification M is for example P. Grivet, Electron Optics. Pergamon Press, Oxford, 1972 and the like.

The beam spot coefficient C is calculated in step S44 from the magnification M obtained as described above, the spherical aberration coefficient Cs, and the like in step S44.

In step S45, it is determined whether or not the value C ^1/4 proportional to the spot diameter of the electron beam is approximately minimum, and if it is not approximately minimum, it returns to step S41 and again, steps S41 to S45. ).

In step S45, when judged to be substantially minimum, the focusing voltage Vf, the beam spot coefficient C, etc. at that time are advanced to step S5 of FIG. 3 as a result of step S4.

In step S5, it is determined whether the beam spot coefficient C is approximately minimum, and if not approximately minimum, the process returns to step S2. In this manner, the processing of steps S2 to S5 is repeated until the beam spot coefficient C is determined to be approximately minimum.

From the above steps S2 to S5, a first loop is formed, and the length (B1 to Bn + 1) of the cylindrical membrane portion and the spiral as the second resistance value distribution which substantially minimizes the beam spot coefficient C. Negative lengths A1 to An are determined.

If it is determined in step S5 that the beam spot coefficient C is approximately minimum, in step S6 the minimum value CO of the beam spot coefficient C and the minimum value MO of the magnification M are determined. . The resistance value distribution (Rz) obtained by the above process can also be calculated | required by the optimum fall method, the conjugate gradient method, etc.

Next, in step S7, the aberration independence function F is calculated using (Number 3), and further, the new beam spot coefficient Cm is calculated using (Number 1).

In step S8, it is determined whether the beam spot coefficient Cm is approximately minimum, and if it is not approximately minimum, it returns to step S2. In this manner, the processes of steps S2 to S8 are repeated until the beam spot coefficient Cm is judged to be approximately minimum.

From the above steps S2 to S8, the second loop is configured.

In step S8, if it is determined that the beam spot coefficient Cm is approximately minimum, the most suitable resistance value distribution is determined by the length (B1 to B1 + 1) of the cylindrical membrane portion at that time, the length (A1 to An) of the spiral portion, and the like. Rzm) is determined. The manufacturing method of the present invention is performed by computer simulation or the like.

Here, the parameter a will be described.

Moreover, the results of the experiments shown below were obtained under the following conditions.

That is, the output side voltage Vs and the incident side voltage VO are 30 kV, the inside diameter D of the tubular substrate 6 is 10 mm, the length Lg is 60 mm, and the electro-optical object point where the electron beam is generated. The distance from the position (z = zo) to the position z-z8a in the z-axis direction of the electrical contact 8a is 20 mm, and the distance from the electrical contact 8b to the image point (z = zs) on the screen 4 is 140 mm.

6 is a graph showing the relationship between the parameter a and the magnification Mm of the electrostatic lens when the beam spot coefficient Cm is minimized.

When a is 0, (number 1) and (number 2) become the same equation, and the magnification M becomes equal to the magnification MO. In this embodiment, MO is about three.

Since the aberration-independent function F depends on the magnification M and not on the spherical aberration Cs, when a becomes larger than 0, the magnification Mm of the electrostatic lens which minimizes the beam spot coefficient CH is It becomes smaller than magnification MO.

Further increasing a, magnification Mm is the length from the electron beam exit point z = zO in the electron beam forming portion 9 to the electrical connection 8a (z = z8a), and the electrical connection 8b. (z = z8b) to the minimum value Ml of the magnification depending on the length from the image point z = zs, the length Lg of the electrostatic lens 5a, and the like.

7 is a graph showing the relationship between the measured value of the parameter (a) and the spot diameter on the screen 4 of the cathode ray tube using the electron gun manufactured based on the manufacturing method of the present invention.

When the parameter a is 0.2, the spot diameter becomes smallest. In the present embodiment, the parameter a is set to 0.2 because of this reason.

In the electron beam forming portion 9, the electron beam actually occurs from a region having some width. However, (Equation 2) can be defined under the condition that the electron beam occurs at one point, and the aberration of the electron beam forming portion 9 is not considered. Also, in Equation 2, the repulsive force between the electron beams is not considered. The influence of the aberration of these electron beam forming portions 9 and the repulsive force between the electron beams on the spot diameter can be made smaller as the magnification decreases. Therefore, when a is enlarged, as mentioned above, the spot diameter of an electron beam becomes small by the influence which became small.

If a is made larger, the spot diameter increases inversely. This reason is considered to be because when a is increased, spherical aberration becomes large, and the influence exceeds the effect by decreasing magnification.

For the above reasons, it is considered that the spot diameter is the smallest when the parameter a is 0.2. In the case of an electron gun manufactured as a conventional manufacturing method, i.e., a = 0, the spot diameter is 0.23 mm (actual value), whereas in the case of the electron gun manufactured by the manufacturing method of the present invention, when a = 0.2, the spot diameter is The minimum value was 0.2 mm (actual value). Moreover, the focusing voltage Vf at this time is 7 kV.

In this way, by selecting the parameter a from the range surrounded by the dotted line in FIG. 7, the spot diameter can be made smaller than before.

Moreover, since the most suitable value of the parameter (a) depends on conditions such as the distance to the electron beam forming portion 9, the electrostatic lens forming portion 5a, the screen 4, and the like, It is not limited.

The electrostatic lens 5a according to the present embodiment is of the same potential type as the incident side voltage VO, the exit side voltage Vs, and the like, but the manufacturing method of the present invention has the incident side voltage VO and the exit side. The present invention can also be applied to bipotential electrostatic lenses having different side voltages Vs.

In addition, although the electrostatic lens 5a in this embodiment is equipped with the electrically insulating tubular board 6 and the resistance structure part 7a etc. which were formed in the inner wall of this tubular board 6, the electrostatic lens is not provided. It can also be configured using a resistance structure such as a ceramic in shape.

In addition, a color cathode ray tube may be formed by providing a structure in which a plurality of electrostatic lenses of the present invention are provided in one cathode ray tube, or a structure in which several electron beams are focused by one electrostatic lens.

EMBODIMENT OF THE INVENTION Hereinafter, the countermeasure against the subject of the temporal stability of the spot diameter in the manufacturing method of this invention is demonstrated.

FIG. 8 (a) is a graph showing the relationship between the distance P from the electro-optical object point to the main plane 25 of the electrostatic lens 5a and the focusing voltage Vf, and FIG. It is a graph showing the relationship between the distance Q from the main plane 25 of the electrostatic lens 5a to the screen 4 and the focusing voltage Vf.

From the eighth (a) and the eighth (b) diagrams, it can be seen that when the distance P and the distance Q are increased, the focusing voltage Vf becomes high. If the distance P is made larger, the distance Q becomes smaller. However, since the effect of the distance P is greater than the influence of the distance Q on the focusing voltage Vf, the distance P is made larger. If the process is performed again, a high focusing voltage Vf can be obtained. As shown in FIG. 8A, when the distance P is 60 mm and 70 mm, the focusing voltages Vf are 6.5 kV and 7.2 kV, respectively.

When the focusing voltage Vf is set high, the difference between the incident side voltage VO and the output side voltage Vs becomes small, so that the voltage load on the resistance structure portion can be reduced. That is, the electrical stability of the resistance structure portion can be improved.

In this way, the time variation of the spot diameter can be reduced by using the manufacturing method of the present invention.

In Table 1, examples of data calculated by the manufacturing method of the present invention are introduced.

Example 2

When the electron current 2a obtained by the manufacturing method of the present invention was experimented with increasing the beam current amount, the time variation of the spot diameter could not be made small enough. Hereinafter, the electron gun which solves this subject is demonstrated.

9 is a block diagram showing an outline of an electron gun in the second embodiment of the present invention. In FIG. 9, the electron gun 2b is comprised by the electrostatic lens 5b, the electron beam formation part 9, etc. In FIG. The electrostatic lens 5b has the same structure as that of the electrostatic lens 5a except for providing the resistive structure 7b. The resistive structure 7b includes cylindrical membrane portions 10a 'to 10g', spiral portions 11a 'to 11f', and the like.

The biggest characteristic about the structure of the resistance structure part 7b is that the thickness of the film | membrane of the electrical connection part 8b vicinity, ie, the emission side of an electron beam, is thinner than the average film thickness of the whole. In this embodiment, the average film thickness is 10 µm and the emission-side film thickness is 5 µm.

When the output side film thickness of the resistive structure 7b is made thin, the resistance value of the portion becomes large, so that the electric field strength on the output side of the resistive structure 7b becomes large. Therefore, the main plane 26 of the electrostatic lens Sb is the exit side approach, the distance P from the electro-optical object point to the main plane 26 of the electrostatic lens is large, and the main plane 26 of the electrostatic lens The distance Q to the image point becomes smaller. When the distance P becomes large, as shown in Fig. 8A, the focusing voltage Vf is set high.

10 is a graph showing the relationship between the ratio of the emission-side film thickness to the average film thickness of the resistive structure 7b and the focusing voltage Vf. It can be seen from FIG. 10 that when the ratio of the emission-side film thickness to the average film thickness is reduced, the focusing voltage Vf becomes high.

Therefore, when the manufacturing method of the present invention is applied to the above-described resistive structure portion, the difference between the incident side voltage VO, the exit side voltage Vs, and the focusing voltage Vf becomes small, and the voltage load to the resistive structure portion is reduced. Can be reduced.

For the above reason, even if the beam current amount is increased, the spot diameter can be kept stable in time.

Hereinafter, an example of the manufacturing method of the resistance structure part 7b in a present Example is demonstrated. 11 (a) and 11 (b) are explanatory views showing the manufacturing process of the resistance structure part 7b in a present Example.

As shown in Fig. 11 (a), a resistor coating liquid made of RuO2, a glass paste, an organic solvent, or the like is applied to the inner wall of the tubular substrate 6, which is a glass tube, and then burned to burn the resistor film 12. To form. When this operation is performed in a state where the tubular substrate 6 is upright, the film thickness of the upper portion of the resistor film 12 is naturally thinned by the weight of the resistor coating film itself.

As shown in FIG. 11 (b), the spiral portions 11a 'to 11f' are formed by scraping the predetermined position of the resistor film 12 in a spiral shape with a sharpener or the like. The remaining portion, which is not cut, becomes cylindrical membrane portions 10a 'to 10g', and a predetermined resistance value distribution can be provided in the resistance structure portion 7b.

As described above, the resistive structure 7b whose output side film thickness of the resistive structure 7b is smaller than the average film thickness can be manufactured.

Further, in the present embodiment, in order to increase the resistance value on the emission side, the emission-side film thickness of the resistance structure 7b is made thin. However, even when the film thickness is uniform or the exit side film thickness is thicker than the average film thickness, the same effect is achieved if the same conditions are satisfied, for example, by using a resistive film having a higher resistivity on the output side than the average of the total resistivity values. You can get it.

Example 3

Hereinafter, the electron gun in the third embodiment of the present invention will be described with reference to FIG.

In FIG. 12, the electron gun 2c is comprised from the electrostatic lens 5c, the electron beam formation part 9, etc. In FIG. The electrostatic lens 5c has the same structure as the electrostatic lenses 5a and 5b except for providing the resistive structure 7c. The resistive structure 7c includes cylindrical membrane portions 10a 'to 10g ", spiral portions 11a" to 11f ", and the like.

The maximum characteristic regarding the structure of the resistance structure part 7c is that the inside diameter D of the tubular board 6, the length Ls of the spiral part 11f "closest to the exit side, etc. are satisfied with (Number 6). In this embodiment, the inner diameter D is 10 mm and the length Ls is 8 mm.

According to the manufacturing method of the present invention, the spherical aberration of the electrostatic lens is relatively small when the lengths of the spiral portions 11d "to 11f" arranged from the electrical connecting portion 8c toward the electrical connecting portion 8b are increased in order. I could get the result. In fact, when a predetermined voltage was applied to the electron gun 2c having the above configuration, it was possible to display an image whose brightness was stable in time.

13 (a) shows the electric field strength EO near the spiral portion 11f "and the electric field strength E near the center of the spiral portion 11f". FIG. 13 (b) is a graph showing the relationship between the length Ls of the spiral portion 11f " and the electric field strength E. FIG.

As shown in FIG. 13 (b), when the length Ls is larger than the inner diameter D of the tubular substrate 6, the electric field strength E of the center portion is equal to the electric field strength EO near the spiral portion 11f ". Therefore, if the electric field intensity EO fluctuates slightly, the electric field intensity E of the center part also fluctuates accordingly.

When the length Ls is equal to or less than the inside diameter D, the vicinity of the cylindrical membrane portions 10f "and 10g" becomes substantially electroless and stabilizes in time, and the variation of the electric field strength E in the center portion is reduced. In this way, time variation of the spot diameter can be reduced.

Further, if the electron gun combines the structural features of the present embodiment with the structural features of the second embodiment, the time variation of the spot diameter can be further reduced.

In addition, if an electron gun having both the structural features of the present embodiment and the structural features of the second embodiment is manufactured by the manufacturing method of the present invention, a cathode ray tube which displays an image with stable brightness at time in high resolution is constituted. can do.

As described above, according to the manufacturing method of the electron gun according to the present invention, the brightness is increased at high resolution by searching for a resistance value distribution that can minimize the beam spot coefficient C and minimize the beam spot coefficient Cm. A cathode ray tube can be provided which displays an image that is stable in time.

In addition, according to the electron gun according to the present invention, the resistance structure on the emission side of the electron beam is provided with a resistive structure composed of a resistor film having a higher value than the average of the total resistance values, so that the time variation of the spot diameter can be reduced.

Further, according to the electron gun according to the present invention, the time variation of the spot diameter can be reduced as the length of the spiral portion closest to the emission side of the electron beam and the inner diameter of the tubular substrate among several spiral portions satisfy predetermined conditions. have.

Claims (9)

A method of manufacturing an electron gun that focuses an electron beam according to a resistance distribution of a resistive structure provided in an electrostatic lens, wherein a second resistance distribution is selected from a first resistance distribution, and the spherical aberration coefficient and the electrostatic force in the second resistance distribution are selected. It is determined whether or not the first beam spot coefficient obtained at the magnification of the lens is approximately minimum, and if not, the first beam spot coefficient is returned as the second resistance distribution is returned as the first resistance distribution. A first loop for searching for a second resistance distribution giving an approximate minimum value of < RTI ID = 0.0 > and < / RTI > Determine whether the second beam spot coefficient obtained by weighting is about minimum or not, and not about minimum And a second loop for searching for a third resistance distribution that gives an approximately minimum value of the second beam spot coefficient as the second resistance distribution is returned to the first loop as the first resistance distribution. The first beam spot coefficient can be obtained by substituting the spherical aberration coefficient obtained by [Equation 4] and the magnification of the electrostatic lens obtained by [Equation 5] into [Equation 2], The second beam spot coefficient includes the aberration ratio dependency function obtained by substituting the minimum value of the magnification of the electrostatic lens, the first beam spot coefficient, and the like into Equation 3, the first beam spot coefficient, and the like. Obtained by substituting into [Equation 1], and the parameter a in [Equation 1] is 0.2 vicinity, The manufacturing method of the electron gun characterized by the above-mentioned.

The method of manufacturing an electron gun as set forth in claim 1, wherein said resistive structure portion is composed of a resistive film formed on an inner wall of said tubular substrate, and said resistive film is formed in an upright position of said tubular substrate. The method of claim 1, wherein the resistance structure portion of the spiral portion formed on the inner wall of the tubular substrate, the length (Ls) of the spiral portion closest to the emission side of the electron beam to the inside diameter (D) of the tubular substrate or less The manufacturing method of the electron gun characterized by the above-mentioned. An electron gun including an electron beam forming portion for generating an electron beam and an electrostatic lens for focusing the electron beam, wherein the electrostatic lens has a resistance having a tubular substrate and a resistance distribution obtained by the method of manufacturing the electron gun according to claim 1. And a structural portion and an electrical connection portion for applying a predetermined voltage to the resistive structural portion formed on the tubular substrate. A cathode ray tube comprising at least one electron gun which generates and focuses an electron beam in a vacuum vessel, and a screen which emits light when the electron beam is irradiated, wherein the electron gun is the electron gun according to claim 5. In an electron gun including an electron beam forming unit for generating an electron beam and an electrostatic lens for focusing the electron beam, the electrostatic lens includes a tubular substrate and a resistor whose resistance value at the emission side of the electron beam is higher than an average of the overall resistance values. And an electrical connection portion for applying a predetermined voltage to the resistance structure portion provided on the tubular substrate. The electron gun according to claim 6, wherein the resistive film has a film thickness on the emission side of the electron beam thinner than an average of the overall film thickness. In an electron gun including an electron beam forming portion for generating an electron beam and an electrostatic lens for focusing the electron beam, the electrostatic lens is configured by alternately arranging a tubular substrate, several cylindrical membrane portions, and several spiral portions. And a predetermined voltage is applied to the resistance structure portion having a length Ls of the spiral portion closest to the emission side of the electron beam among the plurality of spiral portions less than or equal to the inner diameter D of the tubular substrate, and the resistance structure provided on the tubular substrate. An electron gun, characterized by comprising an electrical connection. A cathode ray tube including at least one electron gun for generating and converging an electron beam and a screen for emitting light by beaming the electron beam, wherein the electron gun is an electron gun according to claim 6, 7, or 8 in a vacuum container. Cathode ray tube.

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