KR20020059942A - Electron gun for color cathode ray tube - Google Patents

Abstract

PURPOSE: An electron gun for a color CRT is provided to reduce noise due to the bulb space connector and improve sensitivity of the CRT by improving the structure of the bulb space connector of electron gun. CONSTITUTION: An electron gun comprises a shield cup(40) for shielding magnetic field leakage; and a bulb space connector(45b) welded to the outer surface of the shield cup, and which has an end contacting the inner periphery of a neck glass(21). The bulb space connector has a spring constant of 800N/m or lower. The bulb space connector has a contact portion formed at a flat panel so as to contact the inner surface of the neck glass.

Description

Electron gun for color cathode ray tube

The present invention relates to a color cathode ray tube, and more particularly, to a structure improvement of a bulb space connector of an electron gun that emits an electron beam to a screen.

Generally, as shown in FIG. 1, a color cathode ray tube includes a panel 1 having a fluorescent surface formed on its inner surface so that an image is formed, a funnel 2 formed in a bulb shape and attached to a rear surface of the panel, and a neck portion of the funnel. An electron gun 3 encapsulated in a deflection yoke, a deflection yoke 4 installed on an outer circumferential surface of the front funnel of the electron gun to deflect the electron beam emitted from the electron gun throughout the screen, and the deflected electron beams to be color-coded red, green, and blue. It consists of a shadow mask (6) fixed to the rear of the panel so that the stem pin (5) for applying a voltage to the electron gun (3).

In addition, the electron gun 3 is a device for generating and converging an electron beam by receiving the voltage applied from the stem pin 5, as shown in FIG. 2A, spaced apart from the heater 30 at a predetermined interval in front of the heater. A cathode 31 provided, a first grid electrode 32 spaced apart from the cathode, second, third, and fourth grid electrodes 33, 34, 35 spaced apart from the first grid electrode at a predetermined interval, and The shield cup 40 is attached to the first and second focusing electrodes 36 and 37, the anode 38, and the ends of the anode 38 disposed at a predetermined distance from the four-grid electrode to shield the leakage magnetic field. And a bulb space connector (hereinafter referred to as BSC, bulb space connector, 45a) for supporting the electron gun.

At this time, the electrodes are fixed to the bead glass 42 in order to maintain a constant interval, the shield tab 41 is positioned at the interruption of the bis glass, the alternating current to the second focusing electrode 37 The conductive wire 43 is connected between the stem pin 5 and the focusing electrode 37 to be applied.

In particular, as shown in FIGS. 2B and 2C, the BSC 45a is provided with contact portions 452a protruding in one direction at both ends of the flat plate 451a, and the middle portion thereof is welded to the shield cup 453a to form three BSCs ( 45a) is welded to the outer circumferential surface of the shield cup 40 so as to be spaced at an angle of 120 degrees.

Accordingly, the contact portion 452a of the BSC contacts the conductive layer 44 formed on one inner circumferential surface of the neck glass 21 at six points, thereby applying a high pressure to the anode electrode 38 to form an electrostatic lens. Improve the alignment of the gun.

That is, in the conventional BSC, contact portions 452a are formed at both ends of the flat plate 451a, and the middle portion thereof is welded 453c on the outer circumferential surface of the shield cup 40, so that the contact portions 452a of each BSC are the neck glass 21. Two points of contact with the anode-electrode conductive layer 44 formed thereon are in contact with the inner circumferential surface of the neck glass at six points as a whole.

In the color cathode ray tube having such a configuration, in order to improve image quality, a dynamic voltage is applied to one of the focusing electrodes of the electron gun having the structure as described above, and a constant voltage is applied to the other, or two or more grid electrodes. The same voltage is applied.

Accordingly, when the color cathode ray tube is operated, an electron beam is emitted from the surface of the cathode electrode 31 by the heat generated by the heater 30, and the electron beam is controlled by the first grid electrode 32 which is a control electrode, thereby accelerating the electrode. After being accelerated by the second grid electrode 33, it passes through the third grid electrode 34 and the fourth grid electrode 35, and the first focusing electrode 36 to which a constant voltage is applied, and the same voltage is applied. After passing through the second focusing electrode 37 and accelerated by the anode electrode 38, the phosphor passes through a shadow mask (see Fig. 1 and 6) installed at the rear of the panel.

However, since the same voltage is applied to the second focusing electrode 37 to improve the image quality in the conventional electron gun, as shown in FIGS. 3A and 3B, a large amount of dynamic voltage (at each outside point of the neck glass) AC voltage) is induced with a deviation in the longitudinal direction, and a maximum of 55 to 80% of the voltage applied to the electrode represented by Equation 1 is induced in the neck glass.

V = V _DC + V _{AC / COS} ωt

However, V _DC is a DC voltage applied to each electrode of the electron gun 3, V _{AC · COS} ωt is the same voltage applied to the second focusing electrode 37, ω is the angular frequency of the same voltage, and t is the time to be.

Due to the induced voltage, an electrostatic force is generated between the neck glass 21 and the second focusing electrode 37, and the electrostatic force is changed according to the change in the charge amount on the surface of the second focusing electrode 37 to which the same voltage is applied. , As shown in [Equation 2].

F (t) = (σ _b / 2ε ₀ ) CV _DC + (1/2) (dC / dz) {V _DC ² + (1/2) V _AC ² }

+ (σ _b / 2ε ₀ ) CV _{AC / COS} ωt + (dC / dz) V _DC V _{AC / COS} ωt

+ {(1/4) (dC / dz) V _AC ² _COS 2ωt

F (t) is an electrostatic force interacting between the neck glass 21 and the second focusing electrode 37 to which the same voltage is applied, σ _b is the surface charge density of the neck glass, and ε ₀ is the dielectric constant in vacuum. C is the capacitance between the second focusing electrode 37 and the neck glass 21 to which the same voltage is applied.

When the above electrostatic force acts between the neck glass and the second focusing electrode 37 to which the same voltage is applied, the force of the third, fourth and fifth terms of [Equation 2] is an alternating current component, so the _COS ωt component The second focusing electrode 37 and the conductive wire 43 to which the same voltage is applied are vibrated accordingly because they change with time.

In addition, between the focusing electrode 37 and the electrode opposite thereto, an electrostatic force such as [Equation 3] is generated, which vibrates the electron gun.

F (t) = ε ₀ × S × (dV) ² / (2 × D ² )

Where F (t) is the electrostatic force interacting between the electrode 37 and the electrode facing the same voltage, ε ₀ is the dielectric constant in vacuum, S is the counter area between the electrodes, and dV is the potential difference between the electrodes. And D is the distance between electrodes.

That is, the vibration generated from the second focusing electrode 37 to which the same voltage is applied by the electrostatic force described in [Equation 2] and [Equation 3] is transferred to the stem pin 5 via the conductive wire to which the same voltage is applied. It is transmitted to vibrate the neck glass 21 connected with the stem 215, and part of it is transmitted to the BSC 45a to also vibrate the neck glass 21.

At this time, the conventional BSC (bulb space connector) 45a has a length L of 5 to 6 mm, a width of 3.0 to 3.4 mm, a thickness of about 0.1 mm, and one contact portion 452a for each BSC. Since the spring constant shown is 800 to 1400 N / m, the spring constant per BSC is 1600 to 2800 N / m since one BSC is in contact with the neck glass 21 at two points.

In proportion to the spring constant, the BSC 45a is in contact with the neck glass 21 by the force generated by the electron gun 3 in the range of 4.5 kHz and 8 to 12.5 kHz, so that a large vibration is transmitted to the neck glass. The sensitivity of the cathode ray tube becomes worse.

In addition, the vibration frequency band of 4.5kHz, 10.5kHz, 4-5kHz, 8kHz or more transmitted through the conventional BSC prevents resonance due to the natural frequency matching of the neck glass having the natural frequency ranges of 1.2, 6.7, 7.6, 10.0, and 10.5kHz. Since the high frequency noise is generated in the neck glass, the sensitivity of the cathode ray tube is deteriorated.

The present invention relates to an electron gun of a color cathode ray tube, and to reduce the generation of noise by changing the shape and attenuation ratio of the bulb space connector so that the vibration generated in the electron gun is not transmitted to the neck glass to improve the sensitivity characteristics of the cathode ray tube. There is this.

1 is a schematic cross-sectional view showing a typical colored cathode ray tube

Figure 2a is a side cross-sectional view of the neck portion of a conventional color cathode ray tube sealed with an electron gun

FIG. 2B is a sectional view taken along the line I-I of FIG. 2A

2C is a front view and a side view of a conventional bulb space connector

3A is a graph showing the applied voltage at each position in the longitudinal direction of the neck glass.

3B is a side cross-sectional view showing the voltage measuring position of the neck glass when the same voltage is applied to the focusing electrode of the electron gun;

4A to 4C are front and side views showing a bulb space connector according to a first embodiment of the present invention, and a neck side view of a collar cathode ray tube showing a welding position of the bulb space connector;

5 to 7 are front and side views showing bulb space connectors according to embodiments of the present invention.

8 is a graph showing the relationship between the frequency ratio and the amplitude ratio according to the damping ratio;

9 is a graph showing the vibration damping effect per cover area of the damping foil according to the present invention

10A to 10D are respective graphs showing noise generation frequencies and noise levels generated in cathode ray tubes using respective bulb space connectors according to the present invention.

11 is a graph and table shown to compare the noise generation frequency and the noise level generated in the cathode ray tube using each bulb space connector.

Explanation of symbols on the main parts of the drawings

1 panel 2 funnel

3: electron gun 4: deflection yoke

5: stem pin 6: shadow mask

21: neck glass 40: shield cup

45a, 45b, 45c, 45d, 45e: Bulb space connector (BSC)

The present invention has been made to solve the above problems, the shield cup for shielding the leakage magnetic field and the color of the cathode ray tube consisting of a bulb space connector is welded to the outer circumferential surface of the shield cup one end contact with the inner circumferential surface of the neck glass In an electron gun; The spring constant of the bulb space connector is to provide an electron gun of a color cathode ray tube, characterized in that less than 800N / m.

More preferably, the bulb space connector according to the present invention has one contact portion formed on a plate to contact the inner circumferential surface of the neck glass at one point.

More preferably, the length of the BSC according to the present invention is in the range of 10 to 18 mm.

And, more preferably, a damping member is installed on the BSC surface according to the present invention.

When explaining the present invention according to the accompanying drawings as follows, Figures 4a to 4c is a front view and a side view showing a bulb space connector according to a first embodiment of the present invention color cathode ray indicating the welding position of such a bulb space connector Side view of the coffin.

5 to 7 are front and side views showing a bulb space connector according to embodiments of the present invention, and FIG. 8 is a graph showing a relationship between the frequency ratio and the amplitude ratio according to the damping ratio, and FIG. 9 is the present invention. Is a graph showing the vibration damping effect per cover area of the damping foil.

10A to 10D are graphs illustrating the noise generation frequency and the noise level generated in the cathode ray tube using the bulb space connectors according to the present invention, and FIG. 11 is the cathode ray tube in which the bulb space connectors are used. Graphs and tables are shown to compare the noise generation frequency and the noise level generated.

BSC (bulb space connector, 45b, 45c, 45d, 45e) according to the present invention is to reduce the force transmitted to the neck glass through the BSC vibration generated in the electron gun, such as expressed in [Equation 4] It is formed in the same shape and structure.

F = k × X

However, F is the force that the vibration generated from the electron gun is transmitted to the neck glass, k is the spring constant of BSC (bulbspace connector, 45b, 45c, 45d, 45e), and 3 × modulus of elasticity × moment of inertia / length ³ Derived by X, X represents amplitude.

That is, when the vibration of the electron gun caused by the electrostatic force generated when the same voltage is applied to the second focusing electrode is transmitted to the neck glass 21 through the BSCs 45b, 45c, 45d, and 45e, as shown in the above equation. , Is proportional to the spring constant and amplitude of the BSC.

Accordingly, in the present invention, by reducing the spring constant of the BSC is transmitted to the neck glass 21 to reduce the force to vibrate the neck glass.

To this end, in one embodiment of the present invention, as shown in Figure 4a, the BSC 45b of the first embodiment is formed with a contact portion 452b protruding in one end of the flat plate 451b and the other end is in the shield cup. It is formed to be welded.

Accordingly, the BSC 45b is in contact with the anode voltage applying conductive layer 44 formed on the inner circumferential surface of the neck glass at one point. Contact with the conductive layer.

The BSC 45b of the first embodiment is formed twice as long as the conventional BSC 45a, and its length 2L is 10 to 12 mm, the width is 3.0 to 3.4 mm, and the thickness is about 0.1 mm. Since one BSC comes into contact with the neck glass at one point, as shown in [Equation 4] for obtaining the spring constant, the spring constant per one BSC 45b is 1/16 of the spring constant of the conventional BSC 45a. The spring stiffness is also reduced by 1/16 times.

Accordingly, the spring constant per one BSC 45b of the first embodiment is about 100 to 175 N / m since the spring constant of the conventional BSC 45a is 1/16 times that of 1600 to 2800 N / m. When attached, it is formed with a spring constant of 300 to 525 N / m so that the spring constant is less than the minimum spring constant formed in the conventional BSC, i.e., less than 800 N / m.

As shown in FIG. 4B, the BSC 45b according to the present invention having the above configuration is attached to the outer circumferential surface of the shield cup 40 in the axial direction and formed on the inner surface of the neck glass 21. Are in contact with each other at one point.

On the contrary, as shown in FIG. 4C, one end of the BSC 45b according to the present invention is welded in the circumferential direction of the shield cup 40 so that the BSC 45b has one conductive layer 44 at each point. It can be understood that the contact direction on the shield cup can be formed in various ways.

On the other hand, the second embodiment of the electron gun according to the present invention, as shown in Figure 5, the length is about three times longer than the conventional, 1.5 times than the BSC 45b of the first embodiment in contact with the neck glass per one BSC at a point The BSC 45c is shown to be twice as long.

Accordingly, since the BSC 45c shown in the second embodiment has a length 3L of 15 to 18 mm, a width of 3.0 to 3.4 mm and a thickness of about 0.1 mm, the spring constant per BSC is conventional BSC. The spring constant is reduced to 1/54 of 1600-2800 N / m, and the spring constant is formed at about 30-50 N / m, and the spring stiffness is also reduced to 1/54 of the conventional, so that the spring constant of the BSC (45b, 45c) is 800 N. It is formed at less than / m.

In addition, in the third embodiment of the present invention, as shown in FIG. 6, in order to increase the damping ratio of the BSC, the shape in contact with the conductive layer at one point per one is as shown in the other embodiment, but damping effect has a damping effect. A BSC 45d is shown with the foil attached to the top or bottom surface.

The damping foil 50 is for damping the vibration of the electron gun delivered to the BSC 45d, and changes the vibration of the frequency component transmitted through the BSC 45d from mechanical energy to thermal energy.

The BSC 45d of the third embodiment to which the damping foil 50 is attached has a length of 10 to 12 mm, a width of 3.0 to 3.4 mm, and a thickness of about 0.1 mm, whereas the spring constant is 800 N / m. In particular, it is obtained at 300 to 525 N / m.

7 is a fourth embodiment of the present invention, the length of the BSC 45e is about three times longer than that of the conventional 45a, and the BSC of the first embodiment which contacts the neck glass at one point per BSC ( 45b) is 1.5 times longer and a damping foil 50 having a damping effect is attached to the upper or lower surface.

As such, the reason why the damping foil 50 is attached to the BSC is well represented in a graph showing the relationship between the natural frequency and the amplitude ratio according to the damping coefficient shown in FIG. 8.

At this time, the natural frequency is obtained as the ratio of the frequency to the natural frequency of the conductor to which the dynamic voltage is applied, and the amplitude ratio is calculated as the displacement caused by the force generated when applying the dynamic voltage to the displacement caused by the force generated at the DC voltage. .

That is, the closer the natural frequency ratio is to 1 and the smaller the damping coefficient is, the larger the amplitude ratio becomes. Accordingly, in the present invention, the vibration generated in the conducting wire and the second focusing electrode 37 to which the same voltage is applied by increasing the attenuation coefficient is transmitted through the BSC. It helps to reduce vibrations when transmitted.

Accordingly, when the damping coefficient is increased, the damping effect of the vibration is generated, so that the damping foil having the damping effect is attached to the BSCs 45d and 45e according to the present invention.

At this time, the damping foil attached to the BSC shown in the second and fourth embodiments shows the vibration reduction rate as shown in FIG. 11, and the vibration reduction rate is improved in proportion to the range covering the surface where the vibration has occurred. Therefore, the area attached to the BSC is considered accordingly.

The damping foil 50 is made of aluminum, acrylic viscous polymer, or the like, and is formed of a material having a material loss ratio of 0.1 or more in the frequency range of 1 to 10 Hz.

Analyzing the noise generation frequency of the neck glass to which the BSC (45b, 45c, 45d) according to the present invention having such a configuration can be obtained as shown in the graph shown in Figure 10a to 10d.

At this time, the vibration frequency component measurement formed in the region of each cathode ray tube is analyzed by fast fourier transform (FFT) and operation deflection shape (ODS), and the dotted line is the result of analyzing the noise generation frequency of the conventional electron gun. This is the noise generating frequency range when the BSCs 45b, 45c, 45d according to the present invention are applied.

As shown in FIG. 10A, the noise generating frequency range and the noise level generated in the cathode ray tube when the BSC indicated by the solid line is not mounted, the frequency range generated in the cathode ray tube equipped with the conventional BSC indicated by the dotted line, and When comparing the noise level, it can be seen that when the BSC is not installed, the noise level is low in the frequency band of 4.5 kHz to 6 kHz and 8 kHz or more.

That is, the noise generated by the frequency band of 4.5kHz ~ 6kHz, 8kHz or more can be seen that the frequency component transmitted through the BSC.

Therefore, it can be seen that the noise generated in the frequency band of 4.5 kHz to 6 kHz and 8 kHz or more when the noise is generated in the cathode ray tube can be reduced by applying the improved BSC according to the present invention.

This is shown through the measurement results shown in the graphs of Figs. 10b to 10d, and Fig. 9b is a graph showing the noise generating frequency range and the noise level generated in the cathode ray tube to which the BSC 45b of the first embodiment according to the present invention is applied. It can be seen that the noise frequency components between 4.5 kHz and 6 kHz and the noise frequency components between 8 kHz and 10 kHz are significantly reduced.

That is, since the spring constant of the BSC 45b is reduced by 1/16 times as compared with the related art, the rigidity of the BSC 45b is also weakened by 1/16 times, so that the force transmitted to the neck glass through the BSC is reduced, thereby reducing noise.

In addition, as shown in FIG. 9C, the noise generating frequency range and the noise level generated in the cathode ray tube to which the BSC 45c of the second embodiment according to the present invention whose rigidity is reduced to 1/54 is shown in FIG. 9C. As can be seen, the noise frequency components between 4.5 kHz and 6 kHz and the noise frequency components between 8 kHz and 10 kHz are significantly reduced.

In addition, the stiffness shown in FIG. 9D is reduced to 1/16 as compared with the prior art, and 4.5 kHz is generated even in the noise generating frequency range and the noise level generated in the cathode ray tube to which the BSC 45d of the third embodiment with the damping foil is applied so that the damping ratio is increased. It can be seen that the noise frequency component between ˜6 kHz and the noise frequency component between 8 kHz and 13 kHz are almost eliminated.

Therefore, as shown in Figs. 9B to 9D, the BSC according to the present invention does not eliminate the entire noise generating frequency generated by the electron gun, but the noise frequency component between 4.5 kHz and 6 kHz and the noise frequency component between 8 kHz and 10 kHz. Significantly reduced.

Accordingly, since the noise frequency range with the natural frequency of the neck glass is changed, a high frequency noise generation rate due to resonance is reduced.

In addition, as shown in Figure 11, when compared to the noise generation frequency in the absence of the BSC, it can be seen that the noise reduction effect of more than 15% occurs when the spring constant per BSC is less than 175N / m, experimentally If the spring constant per BSC is below 800N / m, it can be seen that there is a noise reduction effect of about 10%.

In addition, since the BSC according to the present invention has a smaller spring constant than the conventional BSC, the spring stiffness is reduced and the frequency of noise generation is significantly reduced.

As described above, since the spring space is reduced by changing the shape of the bulb space connector so that the vibration generated from the electron gun is not transmitted to the neck glass through the bulb space connector, the spring constant is reduced. Noise is reduced, the sensitivity of the cathode ray tube is improved.

In addition, the present invention reduces the noise generated in the neck glass natural frequency band because the damping member is installed on the upper or lower surface of the bulb space connector to increase the attenuation rate, thereby improving the sensitivity of the cathode ray tube.

Claims (8)

In the electron gun of the color cathode ray tube consisting of a shield cup for shielding the leakage magnetic field and a bulb space connector welded to the outer peripheral surface of the shield cup and one end contacting the inner peripheral surface of the neck glass, The electron gun of the color cathode ray tube, characterized in that the spring constant of the bulb space connector is less than 800N / m. The method of claim 1, An electron gun of a color cathode ray tube, wherein one contact portion is formed on a plate such that the bulb space connector contacts the inner circumferential surface of the neck glass at one point. The method of claim 1, The electron gun of the color cathode ray tube, characterized in that the spring constant of the bulb space connector is less than 530N / m. The method of claim 3, wherein The electron gun of the color cathode ray tube, characterized in that the spring constant of the bulb space connector is less than 175N / m. The method of claim 1, The electron gun of the color cathode ray tube, characterized in that the BSC length is in the range of 10-18mm. The method of claim 1, An electron gun of a color cathode ray tube, characterized in that a damping member is installed on the surface of the BSC. The method of claim 4, wherein The damping member is an electron gun of a color cathode ray tube, characterized in that the material loss ratio is formed from a material of 0.1 or more in the frequency range of 1 to 10 Hz. The method of claim 5, The damping member is an electron gun of a color cathode ray tube, characterized in that formed of aluminum or acrylic viscous polymer.