KR100639050B1 - Electron gun for cathode ray tube and the cathode ray tube having the same - Google Patents

Abstract

Electron gun for cathode ray tube constructed to prevent the shadowing of the shadow mask by blocking a certain amount of the electron beam that does not pass through the beam passing aperture among the electron beam emitted from the electron gun and impinges on the shadow mask, and the electron gun is disposed on the electron beam path And an opening and closing device for repeatedly opening and closing the electron beam path.

The opening and closing device forms three electron beam through holes and is reciprocated in a direction perpendicular to the traveling direction of the electron beam so that the electron beam through holes coincide with and shift the electron beam path, and the shutter member opens and closes the electron beam path. And a solenoid arranged to reciprocate the shutter member while the current flow applied to the coil under the control of an external circuit is turned on / off. The shutter member blocks the flow of the electron beam that will scan the shadow mask body, thereby reducing the electron beam that collides with the shadow mask.

Cathode ray tube, electron gun, electron shutter, shadow mask, doming, electron beam, solenoid, electron shield

Description

Electron gun for cathode ray tube and cathode ray tube comprising same {Electron gun for cathode ray tube and the cathode ray tube having the same}

1 is a cross-sectional view of a cathode ray tube according to the present invention.

2 is an enlarged sectional view of an electron gun according to the present invention;

3 is an enlarged cross-sectional view of the electron gun cut out based on the line A-A of FIG. 1;

4 is a schematic diagram of an opening and closing device among the electron gun according to the present invention;

5 and 6 are cross-sectional views of the opening and closing device respectively showing an electron beam open / close state.

7 is a graph showing the amount of electrons for each of the green, blue, and red electron beams passing through the switching device.

Figure 8 is a graph showing the amount of electrons for each of the green, blue, red electron beam emitted from the electron gun according to the prior art.

The present invention relates to a cathode ray tube, and more particularly, to prevent the shadowing of the shadow mask by blocking a certain amount of the electron beam that does not pass through the beam passing aperture among the electron beams emitted from the electron gun and impinges on the shadow mask. It relates to an electron gun for one cathode ray tube.

In general, a cathode ray tube is a display device in which a three-beam electron beam emitted from an electron gun emits green, blue, and red fluorescent films formed on a fluorescent film screen to realize a predetermined image.

To this end, the cathode ray tube includes a panel having a fluorescent screen formed on its inner surface, a neck portion for mounting an electron gun, and a funnel for connecting the panel and the neck portion, and a shadow having a plurality of beam passing apertures formed inside the fluorescent screen. I wear a mask.

When the electron gun emits three lines of electron beams, the electron beam is deflected by the magnetic field where the deflection yoke is generated to form a raster on the screen of the fluorescent film. These three lines of electron beams are formed at the beam passing aperture of the shadow mask. After they are matched, they pass through and are separated into the corresponding green, blue, and red fluorescent layers to realize accurate colors.

8 is a graph showing the amount of electrons for each of the green, blue, and red electron beams emitted from the electron gun and reaching the shadow mask 1, and the electron beams are continuously emitted while controlling the amount of electrons by the screen signal.

The emission level of the fluorescent film is controlled by the electron amount control, and the emission levels of the green, blue, and red fluorescent films that receive the electron beam through the same beam passing aperture are added and mixed to provide a specific color and contrast per pixel. Will be represented.

However, about 20% of the continuously emitted electron beams pass through the beam passing aperture 1a of the shadow mask 1 and reach the fluorescent screen, and the remaining 80% of the electron beams corresponding to the hatched portions The impingement on the shadow mask 1 causes thermal expansion of the shadow mask 1, that is, a domming phenomenon.

When the doming phenomenon occurs, the path of the electron beam is shifted, which hinders accurate color realization, thereby degrading the quality of the cathode ray tube.

Therefore, as a countermeasure for preventing the shadowing of the shadow mask, a shadow mask may be made of INVAR steel having a low coefficient of thermal expansion instead of an aluminum Kiel (AK) steel having a high coefficient of thermal expansion, or the shadow mask may be formed of the aluminum kicked steel. During fabrication, various methods have been devised to increase the reflectance on the surface of the shadow mask, or to coat various materials with excellent thermal barrier or strength properties.

However, the Invar steel has a disadvantage in that the mechanical workability is not good and the price is high. In addition, the method of coating various materials on the surface of the shadow mask complicates the manufacturing process of the shadow mask, and causes disadvantages such as clogging of the aperture for beam passing.

In particular, since the above methods allow collision of the electron beams that cause the shadowing of the shadow mask, there is no fundamental anti-doming measure.

Therefore, the present invention has been devised to solve the above problems, and an object of the present invention is to reduce the amount of the electron beam that collides with the shadow mask among the electron beams emitted from the electron gun to minimize the temperature rise of the shadow mask to reduce the shadow to expensive invar steel The present invention provides a cathode ray tube that prevents shadowing of shadow masks without making a mask or coating various materials.

In order to achieve the above object, the present invention,

A cathode emitting hot electrons,

A control electrode and a screen electrode for controlling and electron beaming hot electrons emitted from the cathode;

A focus electrode and an anode electrode for focusing and accelerating the electron beam;

A pair of supports for aligning the cathode and the plurality of electrodes in a row,

Provided is a cathode ray tube electron gun including a means for selectively blocking only the electron beam scanning between the beam passing aperture of the shadow mask among the electron beam continuously emitted from the cathode.

In addition, the present invention to achieve the above object,

A panel forming a fluorescent film screen inside the front surface;

An electron gun which emits three stem electron beams toward the fluorescent screen;

A deflection yoke for deflecting the electron beam to form a raster on the screen;

And a shadow mask forming a plurality of beam passing apertures to separate the three-stage electron beam into the corresponding green, blue and red fluorescent films in the fluorescent screen.

The electron gun provides a cathode ray tube having an opening and closing device for repeatedly opening and closing the electron beam path to selectively block only the electron beam scanning between the beam passing apertures of the shadow mask.

Since the electron beam colliding with the shadow mask may be minimized by the opening and closing device, the temperature rise of the shadow mask may be suppressed to prevent the doming phenomenon.

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

1 is a cross-sectional view of a cathode ray tube according to the present invention, in which a cathode ray tube is mounted inside a neck portion 6 and a panel 4 having a fluorescent screen 2 formed thereon, and facing toward the fluorescent screen 2. An electron gun 20 emitting a three-stem electron beam 8, a deflection yoke 12 mounted outside the funnel 10 and generating horizontal and vertical deflection magnetic fields, and a shadow mounted inside the fluorescent screen 2 A mask 14.

The electron gun 20 emits three lines of electron beams 8 whose current density is controlled by a screen signal, and the emitted electron beams 8 are deflected by the magnetic field in which the deflection yoke 12 is generated, thereby providing a shadow mask 14. The beam passing apertures 14a formed in the laser beams are sequentially scanned, and these three stem electron beams 8 are matched in one beam passing aperture 14a and then passed through the corresponding green, blue, and red fluorescence. The film is separated to form the correct color.

At this time, the electron gun 20 according to the present embodiment includes an opening and closing device for repeatedly opening and closing the electron beam path, and the opening and closing device does not pass through the beam passing aperture 14a of the shadow mask 14 by the opening and closing device. And selectively blocks only the electron beam that impinges on the shadow mask 14.

FIG. 2 is an enlarged cross-sectional view of the electron gun according to the present embodiment, and FIG. 3 is a cross-sectional view of the electron gun cut along the line A-A of FIG.

As shown, the electron gun 20 includes three cathodes 22B, 22G, and 22R for emitting hot electrons, and a control electrode 24 and a screen for pre-focusing and electron beaming the hot electrons emitted from the cathode 22. An electrode 26, a focus electrode 28 and an anode electrode 30 for focusing and accelerating the electron beam, a pair of supports 32 for aligning the cathode 22 and a plurality of electrodes in a line, and an electron beam path It includes an opening and closing device 40 for sequentially opening and closing the.

The cathode 22 is heated by a built-in heater to emit hot electrons, and in general, the potential of the control electrode 24 is changed in accordance with the screen signal while the cathode 22 potential and the potential of the screen electrode 26 are fixed. Control the current density, ie the amount of electrons.

The electron beam in which the electron amount is adjusted in this way is prefocused on the prefocus lens 34 formed between the screen electrode 26 and the focus electrode 28, and the main focus lens formed between the focus electrode 28 and the anode electrode 30. The final focusing and acceleration at 36 is directed to the fluorescent screen 2.

At this time, the opening and closing device 40 is disposed between the screen electrode 26 and the focus electrode 28, in particular in front of the prefocus lens 34 to control the flow of the electron beam before pre-focusing. The configuration of the switchgear 40 is schematically shown.

As shown, the opening and closing device 40 includes a shutter member 42 forming an electron beam through hole 42a for each green, blue, and red electron beam, and is disposed at one end of the shutter member 42 and turned on of an external circuit. The solenoid 44 which reciprocates the shutter member 42 by on / off control, and the ground connection part 46 arrange | positioned at the opposite side end of the shutter member 42 are comprised.

The shutter member 42 reciprocates in a direction perpendicular to the electron beam propagation direction, thereby repeatedly blocking the electron beam flow while the electron beam passage hole 42a coincides / deviates from the electron beam path. The shutter member 42 is preferably made of a metal material having a high electrical conductivity to facilitate electron discharge and is made of a material having a low coefficient of thermal expansion so that thermal deformation due to electron collision does not occur.

The solenoid 44 is coupled to the shutter member 42 by a built-in spring member 48, and the shutter member 42 is turned on / off while the current flow applied to the coil 50 is controlled by an external circuit. To reciprocate.

In addition, the ground connection part 46 is connected to an external ground circuit and serves to ground the electrons accumulated in the shutter member 42 by the contact with the shutter member 42 to the outside.

The opening and closing device 40 having such a configuration is firmly fixed to the electron gun by a support not shown.

5 and 6 are cross-sectional views of the switchgear showing the open / blocked states of the electron beams, respectively.

First, as shown in FIG. 5, when the electron beam 8A that scans the beam passage aperture 14a of the shadow mask 14 occurs, the shutter member 42 is in an open state, and in the open state, The electron beam passing holes 42a formed in the member 42 coincide with the electron beam passing holes 26a and 28a formed in the screen electrode 26 and the focus electrode 28, and the electron beam 8A emitted from the cathode 22. Pass it through.

Subsequently, when generating the electron beam 8B which scans between the beam passing apertures 14a, the shutter member 42 is positioned in the electron beam blocking state as shown in FIG. In the movement of the shutter member 42, when an ON signal is applied to the solenoid 44 and a current is supplied to the coil 50, the inside of the solenoid 44 is magnetized while pulling the shutter member 42 toward the solenoid 44. By pulling.

When the shutter member 42 is positioned in the electron beam blocking state as described above, the electron beam through hole 42a formed in the shutter member 42 is displaced from the electron beam path, and the shutter member 42 blocks the electron beam path to prevent the electron beam 8B. Will block the flow.

Thereafter, when the electron beam 8A, which scans the aperture 14a for beam passing again, applies an OFF signal to the solenoid 42 to stop supply of current flowing through the coil 50, the spring member 48 is caused by the elastic force. The shutter member 42 passes the electron beam 8A while returning to the open state as shown in FIG.

At this time, the upper end of the shutter member 42 is in contact with the ground connection part 46 in the open state, and the electrons accumulated in the shutter member 42 in the blocking state by the ground connection part 46 are discharged to the outside.

By controlling the electron beam flow by the operation of the opening and closing device 40 as described above to reduce the amount of electron beam impinging on the shadow mask (14).

FIG. 7 is a graph showing the amount of electrons for each of the green, blue, and red electron beams passing through the opening and closing device 40 to reach the shadow mask 14. As shown in the drawing, the electron beam is emitted while the amount of electrons is controlled by the potential change of the control electrode 24, and is scanned by the operation of the opening and closing device 40 in addition to the beam passing aperture 14a in the shadow mask 14 body. A certain amount of electron beam is blocked.

As a result, it can be seen that the amount of electrons impinging on the shadow mask 14 indicated by hatching is significantly reduced compared to the conventional cathode ray tube (shown in FIG. 8).

Here, since the time required for the reciprocating movement of the shutter member is in units of nanosecs (ns), it is difficult to completely block all the electron beams colliding with the shadow mask due to the operating characteristics of the switching device, but 30 to 70% of the electron beams collide with the shadow mask. The degree can be easily cut off.

In general, considering the observation that domming does not occur in an aluminum-kilted steel shadow mask even when only 30% of the amount of electrons reaching the shadow mask is blocked, the amount of electrons colliding with the shadow mask in the electron gun according to the present embodiment Blocking only about 30% is effective in preventing doming.

Therefore, the cathode ray tube according to the present embodiment has an advantage of effectively reducing the amount of electrons colliding with the shadow mask to fundamentally prevent the shadowing of the shadow mask.

Although the preferred embodiments of the present invention have been described above, the present invention is not limited thereto, and various modifications and changes can be made within the scope of the claims and the detailed description of the invention and the accompanying drawings. Naturally, it belongs to

As described above, the cathode ray tube according to the present invention can selectively reduce only the electron beam that collides with the shadow mask by the operation of the switching device. As a result, the quality of the cathode ray tube may be further improved by fundamentally preventing the shadow mask from causing the degradation of the cathode ray tube.

Claims (10)

A cathode for emitting hot electrons; A control electrode and a screen electrode which control and electron beam hot electrons emitted from the cathode; A focus electrode and an anode electrode for focusing and accelerating the electron beam; A pair of supports for aligning the cathode and the plurality of electrodes in a row; And means for selectively blocking only the electron beam scanning between the beam passing apertures of the shadow mask among the electron beams continuously emitted from the cathode to prevent doming. The electron gun for a cathode ray tube according to claim 1, wherein said means comprises an opening and closing device arranged on the electron beam path to open and close the electron beam path repeatedly. The method of claim 2, wherein the opening and closing device, A shutter member for forming three electron beam through holes, the shutter member reciprocating in a direction perpendicular to the traveling direction of the electron beam to open and close the electron beam path while the electron beam path coincides with and shifts the electron beam path; And a solenoid disposed at one end of the shutter member, the solenoid configured to reciprocate the shutter member by on / off control of an external circuit. delete The method of claim 3, wherein the opening and closing device, An electron gun for a cathode ray tube disposed at one end of the opposite side of the shutter member, further comprising a ground connection portion which is grounded to the outside and grounds electrons accumulated in the shutter member to the outside in contact with the shutter member. The electron gun of claim 2, wherein the opening and closing device is disposed between the screen electrode and the focus electrode. A panel forming a fluorescent film screen inside the front surface; An electron gun that emits three stem electron beams toward the fluorescent screen; A deflection yoke for deflecting the electron beam to form a raster on the screen; And a shadow mask forming a plurality of beam passing apertures to separate the three-stage electron beam into the corresponding green, blue and red fluorescent films in the fluorescent screen. And the electron gun has an opening and closing device for repeatedly opening and closing the electron beam path to selectively block only the electron beam scanning between the beam passing apertures of the shadow mask. The method of claim 7, wherein the opening and closing device, A shutter member for forming three electron beam through holes, the shutter member reciprocating in a direction perpendicular to the traveling direction of the electron beam to open and close the electron beam path while the electron beam path coincides with and shifts the electron beam path; And a solenoid disposed at one end of the shutter member, the solenoid reciprocating the shutter member by on / off control of an external circuit. The method of claim 8, wherein the opening and closing device, The cathode ray tube is disposed at one end of the opposite side of the shutter member, and further comprising a ground connection part which is grounded to the outside and grounds electrons accumulated in the shutter member to the outside in contact with the shutter member. The cathode ray tube according to claim 8, wherein the opening and closing device is disposed between the screen electrode and the focus electrode of the electron gun.

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