KR20010077103A - Scanning method of electron beam for beam index type CRT - Google Patents

Abstract

PURPOSE: A method for scanning an electron beam of a beam index type cathode ray tube is provided to realize high resolution by using a fine beam and to maintain the uniform focus characteristics on the whole screen by controlling a vertical microscope of the electron beam. CONSTITUTION: In the method for scanning the electron beam of the beam index type cathode ray tube, a panel(4), a funnel(6), a neck portion(8), electron guns(10a, 10b), an optical detector(12), deflection yokes(14a, 14b), an indexing circuit portion(16) are included. The panel(4) is formed in a fluorescent film screen. The funnel portion(6) is formed at the rear of the panel(4). The neck portion(8) is formed on the same axis at the rear of the funnel portion(6). The electron guns(10a, 10b) are installed on the inner circumference of the neck portion(8). The deflection yokes(14a, 14b) are stuck on the outer circumference of the funnel portion(6). The optical detector(12) detects the index light emitted from the index stripe and converts it into the index signal. The indexing circuit portion(16) is connected with the electron gun(10a, 10b).

Description

Scanning method of electron beam for beam index type CRT

The present invention relates to a beam index type cathode ray tube, and more particularly, to realize high resolution by implementing a fine beam diameter, and to adjust a vertical beam diameter of an electron beam to maintain a uniform focus characteristic across the entire surface. It relates to an electron beam scanning method of.

In general, the beam index type cathode ray tube generates, focuses, and accelerates an electron beam from an electron gun, and the basic principle of realizing an image by scanning it on a fluorescent film screen is the same as that of a general cathode ray tube. Is doing.

FIG. 7 is a cross-sectional view of a beam index type cathode ray tube according to the prior art, and FIG. 8 is an enlarged view of a fluorescent film screen. When the electron gun 1 emits a single electron beam 5 toward the fluorescent film screen 3, the electron beam (5) excites the index stripe 7 to generate a light pulse (index light) in the near ultraviolet region, which is detected by the photodetector 11 through the light collecting plate 9 and converted into an index signal. The index signal emits an accurate color signal in synchronization with the color signal in the indexing circuit unit 13 to implement a desired color.

Since the beam index type cathode ray tube having such a configuration does not have a shadow mask, it is necessary to implement a horizontal beam diameter D1 having a limited size so that the electron beam 5 does not emit the adjacent fluorescent film stripe 15. For this reason, the electron gun 1 provided in the beam index type cathode ray tube should realize a very small horizontal beam diameter compared to the electron gun provided in the general cathode ray tube, and a finer horizontal beam diameter is required to realize high resolution.

Thus, in order to implement a fine beam diameter, conventionally, a method of expanding the main lens diameter of the electron gun 1 by employing a funnel portion 19 having a larger diameter than the neck portion 17 or using a magnetic focus method is used. I adopt it. However, when the neck portion 17 is increased in diameter, the focus characteristic is excellent, but the power required for electron beam deflection is greatly increased to increase the power consumption of the entire cathode ray tube, and both techniques have a certain limitation in implementing the fine beam diameter. There is this.

The electron beam 5 emitted from the electron gun 1 is deflected by a magnetic field generated by a deflection yoke (shown by a broken line) to form a raster. As shown in FIG. 9, the electron beam 5 moves up and down the screen. The vertical beam diameter D2 increases as the distance from the virtual central horizontal axis, which is divided into two parts, is increased to the upper and lower parts of the screen, thereby deteriorating focus characteristics at the periphery of the screen. Therefore, when the vertical beam diameter is set based on the periphery of the screen in order to improve the focus characteristic at the periphery of the screen, it is difficult to maintain the image quality at the center of the screen.

In addition, there is a camel-type cathode ray tube of a prior art, which employs a plurality of electron guns and divides the screen. This has the advantage of shortening the electric field of the cathode ray tube and improving the focus characteristic of the screen, but it is difficult to harmonize the divided screen into one screen, and there is no change in the maximum current value of each electron beam emitted from the plurality of electron guns. There is a limit to the implementation of the fine beam diameter.

Therefore, the present invention was devised to solve the above problems, and an object of the present invention is to make a high-resolution beam index cathode ray by realizing fine beam diameter by reducing the maximum current value of each electron beam by allowing a plurality of electron guns to scan the same screen. The present invention provides a method for electron beam scanning of a tube.

Another object of the present invention is to provide an electron beam scanning method of a beam index type cathode ray tube which can maintain a uniform focus characteristic over the entire surface by adjusting the vertical beam diameter by adjusting the overlapping degree of the electron beam emitted from each electron gun.

1 is a rear perspective view of a beam index type cathode ray tube according to the present invention;

2 is a cross-sectional view of a beam index type cathode ray tube according to the present invention.

3 is a graph showing the horizontal beam diameter of the electron beam according to the change of the cathode current value.

4A and 6A are enlarged views of the fluorescent screen.

4B and 6B are graphs showing current density according to the vertical beam diameter of the electron beam.

5 is a schematic diagram illustrating a central horizontal axis of the screen.

7 is a cross-sectional view of a beam index type cathode ray tube according to the prior art.

8 is an enlarged view of a fluorescent screen;

9 is a schematic diagram showing the shape of an electron beam for each position of a screen.

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

A fluorescent film screen formed on an inner surface of the panel and having an index stripe;

A neck portion coupled to the rear of the panel and a rear portion of the panel and having a plurality of neck portions formed on the same axis;

A plurality of electron guns mounted on the inner circumferential surface of each neck portion to emit electron beams,

A plurality of deflection yokes mounted on an outer circumferential surface of the funnel portion facing the neck portion;

A photo detector for detecting the index light emitted from the index stripe and converting the index light into an index signal;

A beam index type cathode ray tube comprising an indexing circuit unit for synchronizing the index signal with a color signal to apply an accurate color signal to a plurality of electron guns,

The electron beam scanning method of the beam-index type cathode ray tube which deflects these electron beams so that the said electron beam emitted from each electron gun may scan the same area | region of a fluorescent film screen simultaneously is provided.

As described above, by simultaneously scanning the entire surface of the fluorescent film screen with a plurality of electron beams, the maximum current value and the average current value of each electron beam may be reduced, thereby realizing a smaller horizontal beam diameter. In addition, by arranging each electron beam side by side on the vertical axis, it is possible to control the vertical beam diameter of the final electron beam by adjusting the degree of overlap of each electron beam on the vertical axis.

As a result, the present invention realizes high resolution by implementing a fine beam diameter, and has the advantage of maintaining a uniform focus characteristic over the entire screen by adjusting the vertical beam diameter of the final electron beam.

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

1 is a rear perspective view of a beam index type cathode ray tube according to the present embodiment, and FIG. 2 is a cross-sectional view of the beam index type cathode ray tube according to the present embodiment.

As shown, the present embodiment has a panel 4 having a fluorescent screen 2 formed therein, a funnel portion 6 coupled to the rear of the panel 4, and a rear portion of the funnel portion 6. A plurality of neck portions 8 formed on the same axis, a plurality of electron guns 10 mounted on the inner circumferential surface of each neck portion 8, and a photo detector attached to the outer circumferential surface of the light receiving window 6a of the funnel portion 6 (12), a plurality of deflection yokes (14) attached to the outer circumferential surface of the funnel portion (6) facing each neck portion (9), and an index connected to the photo detector (12) and the plurality of electron guns (10). And a circuit portion 16.

The neck part 8, the electron gun 10, and the deflection yoke 14 may be provided in plural, and as illustrated, for example, a pair may be arranged side by side at a predetermined interval on the vertical axis of the screen.

In this embodiment, when the first and second electron beams 18a and 18b are respectively emitted from the first electron gun 10a and the second electron gun 10b, the first deflection yoke 14a and the second deflection yoke ( 14b) generates respective horizontal and vertical deflection magnetic fields such that the electron beams 181 and 18b emitted from the pair of electron guns 10a and 10b simultaneously scan the entire surface of the fluorescent film screen 2 to produce corresponding electron guns 10a and 10b. Deflect electron beams 181 and 18b emitted from

That is, even if the first and second electron guns 10a and 10b are located at the upper and lower portions of the screen that divide the screen up and down, respectively, the pair of deflection yokes 14a and 14b deflect the corresponding electron beams 18a and 18b. One screen is configured by simultaneously scanning the same area of the fluorescent film screen 2 with the same trajectory.

By emitting the electron beams 181, 18b from the pair of electron guns 10a, 10b by the electron beam scanning method described above, and simultaneously scanning the fluorescent film screen 2, the electron beam 18 causes the index stripe 20 to be scanned. Simultaneously exciting to emit index light, the emitted index light is detected by the photo detector 12 and converted into an index signal, which is synchronized with the color signal in the indexing circuit section 16 as the correct color signal as the first and second signals. It is transmitted to the electron guns 10a and 10b.

At this time, the pair of light detectors 12 for detecting the index light are arranged side by side at a predetermined interval on the horizontal axis of the screen intersecting the vertical axis where the pair of electron guns 10a and 10b are arranged to increase the light collecting efficiency of the index light.

As described above, the pair of electron guns 10a and 10b and the deflection yoke 14a and 14b simultaneously constitute a screen with a pair of electron beams 18a and 18b, thereby resulting in the final electron beam 18 reaching the fluorescent film screen 2. ) Has a higher current density than the electron beam in the general beam index type cathode ray tube.

Therefore, even if the maximum current value and the average current value of the electron beam 18 emitted from each electron gun 10 are reduced, the same brightness as that of the general beam index type cathode ray tube can be realized. Therefore, the maximum current value and the average current value of each of the electron beams 18a and 18b can be obtained. Can be reduced.

3 is a graph showing the change in the horizontal beam diameter of the electron beam according to the change of the cathode current value Ik with respect to one electron gun. As the cathode current value increases, the horizontal beam diameter of the electron beam increases, for example, while the cathode current value exceeds 1500 μA. It can be seen that the horizontal beam diameter of the electron beam is rapidly increasing.

Thus, reducing the maximum value of the cathode current, that is, the maximum current value of the electron beam, can effectively reduce the horizontal beam diameter of the electron beam.

Therefore, when the first and second electron guns 10a and 10b emit the electron beams 18a and 18b having the maximum current value and the average current value reduced than before, the first and second electron beams 10a and 10b emitted from the respective electron guns 10a and 10b. The electron beams 18a and 18b implement a horizontal beam diameter reduced according to the reduced current value. Since each of the first electron beam 18a and the second electron beam 18b reaches the same point in the fluorescent screen 2, the horizontal level of the final electron beam in which the first electron beam 18a and the second electron beam 18b are combined. Since the beam diameter is substantially the same as the horizontal beam diameter of each of the first and second electron beams 18a and 18b, a smaller horizontal beam diameter is realized.

As a result, a reduced horizontal beam diameter can be prevented from emitting light of adjacent other fluorescent film stripes, and has a further advantage in realizing high resolution.

Also in this embodiment, a pair of deflection yokes 14a, 14b deflect these electron beams such that the first and second electron beams 18a, 18b are arranged side by side on the vertical axis, and each of the electron beams 18a, 18b has a vertical axis. It is possible to control the vertical beam diameter of the final electron beam by adjusting the degree of overlap on the image.

4A is an enlarged view of a fluorescent screen, and FIG. 4B is a graph showing the vertical beam diameter of each electron beam and the density of the electron beam. The intensity of the deflection magnetic field generated by the first and second deflection yokes 14a and 14b is adjusted. The first and second electron beams 18a and 18b reaching the same point in the fluorescent film screen 2 are arranged to be shifted by a predetermined portion on the vertical axis. Thus, the center distance t between the vertical axes of the first and second electron beams 18a and 18b may be adjusted to enlarge or reduce the vertical beam diameter of the final electron beam.

As described above, the vertical beam diameter of the final electron beam reaching the fluorescent film screen 2 can be controlled to ensure uniform focus characteristics over the entire screen, which will be described in more detail. As the emitted electron beam is scanned closer to the central horizontal axis A that bisects the screen up and down as shown in FIG. 5, the first and second deflection yokes 14a and 14b are disposed between the vertical axes of the respective electron beams 18a and 18b. The first and second electron beams 18a and 18b are deflected to increase the center distance t to enlarge the vertical beam diameter of the final electron beam.

As the electron beam is scanned farther from the central horizontal axis A, as shown in FIGS. 6A and 6B, the first and second deflection yokes 14a and 14b have the center distance t between the vertical axes of the respective electron beams 18a and 18b. The first and second electron beams 18a and 18b are deflected to minimize ') to minimize the vertical beam diameter of the final electron beam.

Therefore, since the vertical beam diameter between the center portion and the peripheral portion of the screen due to the electron beam deflection is canceled, a uniform vertical beam diameter can be realized throughout the entire screen, thereby maintaining uniform focus characteristics across the center portion and the peripheral portion of the screen.

As described above, the present embodiment arranges the pair of electron guns and the deflection yokes side by side on the vertical axis of the screen. However, in addition to the above-described embodiment, the pair of the electron guns and the deflection yoke are arranged side by side on the horizontal axis of the screen. It is also possible to have a configuration arranged side by side and a configuration having two or more electron gun and the deflection yoke on the same axis, the electron beam scanning method of the deflection yoke is the same in all embodiments.

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 the range of.

As described above, the beam index type cathode ray tube according to the present invention simultaneously scans the front surface of the fluorescent screen with a plurality of electron beams, thereby reducing the maximum current value of the electron beam emitted from each electron gun, thereby realizing a reduced horizontal beam diameter. It can be easily realized.

In addition, by changing the center distance between the vertical axis of the electron beam emitted from each electron gun to control the vertical beam diameter of the final electron beam it is possible to maintain a uniform focus characteristic throughout the screen.

Claims (7)

A fluorescent film screen formed on an inner surface of the panel and having an index stripe; A neck portion coupled to the rear of the panel and a neck portion coupled to the rear of the panel and having a plurality formed on the same axis; A plurality of electron guns mounted on the inner circumferential surface of each neck portion and emitting electron beams; A plurality of deflection yokes mounted on an outer circumferential surface of the funnel portion facing the neck portion; A photo detector for detecting the index light emitted from the index stripe and converting the index light into an index signal; A beam index type cathode ray tube comprising an indexing circuit unit for synchronizing the index signal with a color signal to apply an accurate color signal to a plurality of electron guns, And a beam index type cathode ray tube for deflecting the electron beams so that the electron beams emitted from the electron guns simultaneously scan the same region of the fluorescent film screen. The method of claim 1, And a plurality of deflection yokes are arranged so that the electron beams emitted from each electron gun are arranged side by side on a vertical axis to deflect these electron beams so as to have a predetermined center-center distance. The method of claim 2, The electron beam scanning method of the beam index type cathode ray tube which deflects these electron beams, increasing the center distance between vertical axes as the electron beam emitted from each said electron gun approaches the center horizontal axis of a screen. The method of claim 2, And a beam index type cathode ray tube deflecting the electron beams while minimizing the center distance between the vertical axes as the electron beams emitted from the electron guns are moved away from the central horizontal axis of the screen. The method of claim 1, And a plurality of neck portions, an electron gun, and a deflection yoke are arranged side by side at predetermined intervals on the vertical axis of the screen. The method of claim 1, And a plurality of neck portions, an electron gun, and a deflection yoke are arranged side by side at predetermined intervals on a horizontal axis of the screen. The method of claim 1, And a plurality of neck portions, an electron gun, and a deflection yoke in pairs.