KR20020007018A - Beam index type CRT - Google Patents

Abstract

PURPOSE: A beam index type cathode ray tube is provided to correct efficiently an electron beam by using an auxiliary deflection device for obtaining a big rotary angle. CONSTITUTION: A fluorescent layer screen(2) having an index stripe is formed on an inner face of a panel(4). An electron gun(12) is formed on an inner circumference of a neck portion(8) in order to emit an electron beam to the fluorescent layer screen(2). The electron gun(12) is formed with a cathode and a multitude of grid electrodes. An optical detector(18) is formed on an outer face of a funnel(6) for connecting the panel(4) with the neck portion(8) in order to detect an index beam from the index stripe. An index circuit portion(20) applies correctly a color signal to the electron gun(12) by synchronizing an index signal of the optical detector(18) with the color signal. A deflection yoke(14) deflects the electron beam by generating a deflective magnetic field. An auxiliary deflection portion(22) is installed on an outer circumference of the neck portion(8) in order to correct a trigger slope of the electron beam.

Description

Beam index type cathode ray tube {Beam index type CRT}

According to the present invention, in the beam index type cathode ray tube having an auxiliary deflection apparatus for correcting the electron beam inclination, the auxiliary deflection apparatus is provided in an elliptical shape to generate an asymmetric magnetic field to efficiently perform the correction of the electron beam with a smaller current value. It relates to a beam index type cathode ray tube.

In general, a color cathode ray tube is a display device that implements a predetermined screen by emitting a fluorescent screen by using an electron beam emitted from an electron gun. The color cathode ray tube is widely used for a home TV and a computer monitor due to its relatively low price and vivid image quality.

The color cathode ray tube adopts a shadow mask to separate the three-beam electron beam emitted from the electron gun into the corresponding R, G, and B fluorescent films. When the screen size is large or the electron beam is a high current region, the shadow mask is thermally expanded. Color purity decreases, and because the electron beam is affected by the geomagnetic field, it is necessary to install an inner shield for shielding the geomagnetic field, and to install a degaussing circuit and coil in the set circuit. There are many limitations.

In order to overcome the limitations of the color cathode ray tube described above, Japanese Patent Laid-Open Nos. 61-68836 and 63-105438 disclose a beam index type cathode ray tube without the need for a shadow mask and an inner shield. Doing.

The beam index type cathode ray tube forms an index stripe on a fluorescent film screen, and includes a light collecting plate and an optical sensor in the funnel that detect the index light. When the electron beam emitted from the electron gun excites the index stripe and emits the index light, It is designed to realize a desired color by synchronizing the index signal detected by the light collecting plate and the optical sensor with the color signal.

Unlike the normal cathode ray tube having a shadow mask, such a beam index type cathode ray tube emits a single electron beam, and thus has zero misconvergence, which is a deviation of three stem electron beams, and a shadow mask does not have a doming. It has a big advantage that there is no phenomenon and moire phenomenon.

However, the beam index type cathode ray tube is limited in terms of driving principle by the electron beam size, in particular the horizontal beam diameter. That is, as shown in FIG. 10, the electron beam size reaching the fluorescent film screen 1 is twice the width A of the black matrix film 3 plus the width B of one of the fluorescent film stripes 5. It is important to limit the horizontal beam diameter of the electron beam small because it must be smaller so as not to invade other colors.

Furthermore, as shown in FIG. 11, the windshield of the cathode ray tube is rectangular, and since the electron beam is deflected with respect to the center point of the screen, the electron beam is inclined at the periphery of the screen instead of being arranged vertically. This phenomenon becomes more serious as the screen is enlarged and planarized. According to the experiment, the electron beam of the 29-inch cathode ray tube is inclined at an angle of 15 degrees or more with the vertical axis.

The inclination of the electron beam increases the horizontal beam diameter of the electron beam and causes other color violations, and when one or more index stripes emit light, index signals are overlapped, which makes it impossible to accurately synchronize the color signals in the index circuit part. It has its drawbacks.

As a result, various techniques have been devised to correct the inclination of the electron beam. One of them, Japanese Patent Publication No. 57-199152, employs an auxiliary deflection device, and employs a symmetric quadrupole magnetic field for an electron beam passing through an electron gun. A method of rotating an electron beam by generating vi) is disclosed.

That is, when the auxiliary deflecting device 7 having the structure shown in FIG. 12 is mounted on the outer circumferential surface of the neck portion, the electron beam is rotated by the force F in the direction of the arrow by the magnetic force B from the N pole toward the S pole. By adjusting the amount of current supplied from the inclination correcting circuit 9 and the current direction, the inclination of the electron beam is corrected by adjusting the intensity of the magnetic force for each position at which the electron beam is scanned.

However, in the symmetrical 4-pole structure as described above, the magnetic fields are difficult to penetrate because the magnetic fields cancel each other at the center of the electron beam. There is a disadvantage. In addition, since the symmetrical four-pole structure receives the greatest force in the 45 ° direction, the electron beam is stretched in the 45 ° direction without the rotation of the electron beam at an additional angle even when the magnetic field is gradually applied.

As a result, the auxiliary deflection apparatus according to the prior art requires a considerable current supply to correct the inclination of the electron beam, and has a disadvantage in that the rotation angle of the electron beam is limited.

Therefore, the present invention is designed to solve the above problems, the object of the present invention is to compensate for the disadvantages of the existing auxiliary deflection device, it is possible to efficiently perform the correction of the electron beam with a smaller current supply, the same current supply The present invention provides an auxiliary deflection device capable of obtaining a large rotation angle and a beam index type cathode ray tube including the same.

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

2 is a front view of the auxiliary deflection apparatus;

3 and 4 are diagrams showing electron beam shapes simulated in the auxiliary deflection apparatus according to the prior art and the present invention, respectively.

5 and 6 are schematic views showing a part of the auxiliary deflection apparatus according to the prior art and the present invention, respectively.

7 is a front view of the auxiliary deflection apparatus according to another embodiment.

8 to 9 are graphs showing input waveforms of the auxiliary deflection apparatus.

10 is an enlarged view of a fluorescent screen.

11 is a schematic diagram for explaining an electron beam tilt.

12 is a front view of the auxiliary deflection apparatus according to the prior art.

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;

An electron gun embedded in the neck portion and emitting an electron beam toward the fluorescent screen;

A photo detector provided on an outer surface of the funnel connecting the panel and the neck portion to detect index light emitted from the index stripe;

An index circuit for applying an accurate color signal to the electron gun by synchronizing the index signal provided from the photo detector with a color signal;

A deflection yoke for generating a deflection magnetic field to deflect the electron beam emitted from the electron gun;

Beam index type cathode ray which is mounted on the outer circumferential surface of the neck portion and includes four auxiliary poles facing each other in the horizontal and vertical directions of the screen to have an elliptical arrangement to apply an asymmetric quadrupole magnetic field to the electron beam passing through the electron gun. Provide a coffin.

As the auxiliary deflecting device generates an asymmetric magnetic field, the rate at which magnetic fields cancel each other in the middle portion of the electron beam passing through is reduced, thereby enhancing the influence of the magnetic field on the electron beam. As such, the present invention has the advantage of correcting the inclination of the electron beam with higher efficiency even if a lower current is provided to the auxiliary deflection apparatus.

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 beam index type cathode ray tube according to the present embodiment, wherein the beam index type cathode ray tube includes a panel 4 having a fluorescent screen 2 formed therein and a funnel coupled to a rear of the panel 4. (6) and neck portion (8), electron gun (12) for emitting a single electron beam (10) toward the fluorescent film screen (2), deflection yoke (14) mounted on the outer circumferential surface of the funnel (6), and an index A photo detector 18 for detecting light 16, an index circuit 20 electrically connected to the electron gun 12 and the photo detector 18, and an auxiliary deflection device 22 for rotating the electron beam 10. ).

The fluorescent film screen 2 includes R, G, and B fluorescent film stripes 26 continuously formed between the black matrix films 24, an aluminum reflecting film 28 provided for improving luminance, and an aluminum reflecting film 28 Is formed at predetermined intervals, and is provided with an index stripe 30 that receives the electron beam 10 and emits the index light 16.

The photodetector 18 is attached to the outer surface of the transparent light receiving window 6a of the funnel 6, and usually consists of a light collecting plate 32 and an optical sensor 34, which collects the ultraviolet region (approximately 400). nm) of the index light is converted into an optical signal having a good response sensitivity of the optical sensor 34 (600 to 900 nm), and the optical sensor 34 converts an optical signal having a long wavelength provided by the light collecting plate 32 into an electrical signal. The signal is converted into an index signal and applied to the index circuit unit 20.

When the index circuit unit 20 synchronizes the index signal provided by the optical sensor 34 with the color signal and applies the correct color signal to the electron gun 12, the electron gun 12 emits an electron beam 10 corresponding to the color signal. The emitted electron beam is deflected by the deflection magnetic field generated by the deflection yoke 14 to reach the designated fluorescent film stripe 26 to express the correct color.

At this time, the electron beam 10 is deflected by the horizontal and vertical magnetic fields in which the deflection yoke 14 is generated based on the center point of the screen to form a raster, and the auxiliary deflection device 22 is an electron beam 10. ) Rotates the electron beam at a predetermined angle in advance before being deflected into the deflection yoke 14 and serves to correct the inclination of the electron beam at the periphery of the screen due to deflection.

FIG. 2 is a front view of the auxiliary deflecting device, and more specifically, the auxiliary deflecting device 22 is fixed to the inner circumferential surface of the elliptical support 36 and the elliptical support 36 mounted on the outer circumferential surface of the neck portion 8 and is horizontal to the screen. Four magnetic poles 38a, 38b, 38c, 38d disposed opposite to the direction H and in the vertical direction V, the coil 40 winding the four magnetic poles sequentially, and connected to both ends of the coil 40 And the inclination correction circuit section 42 for providing a current to the coil.

The four magnetic poles 38 are elliptical in which the distance between the first and second magnetic poles 38a and 38b facing in the horizontal direction is larger than the distance between the third and fourth magnetic poles 38c and 38d facing in the vertical direction. Of the electron guns 12 including the cathode K and the plurality of grid electrodes G1 to G4, in particular, facing the focus electrode G3 to affect the electron beam before entering the main focus lens 44. Crazy

When the auxiliary deflecting device 22 having the above-described configuration provides a predetermined current to the coil 40 in the inclination correcting circuit section 42, the four poles 38 wound around the coil 40 face each other in the horizontal and vertical directions. As a pair of magnetic poles are magnetized to the same polarity, a magnetic field is formed inside the auxiliary deflector 22 to rotate the electron beam 10.

That is, when charged particles enter a magnetic field, they receive a force, a so-called Lorentz force. As illustrated, the first and second magnetic poles 38a and 38b are magnetized to the S pole, and the third and fourth magnetic poles ( When 38c and 38d are magnetized to the N pole, the magnetic force B exits the N pole and goes to the S pole, and the current direction (the direction opposite to the electron beam propagation direction) passes under the ground, resulting in Lorentz force ( F) becomes the arrow direction.

Therefore, the electron beam 10 passing through the auxiliary deflection device 22 rotates by a predetermined angle with respect to the horizontal axis under Lorentz force in the direction of the arrow, thereby compensating the rotation due to the deflection to the periphery of the screen and together with the center of the screen. This allows the electron beam to enter vertically at the periphery.

At this time, the auxiliary deflection device 22 according to the present embodiment has the following advantages over the circular structure by arranging four magnetic poles in an elliptical shape. First, a smaller current value is required to rotate the electron beam at a desired angle. The second is that the rotation angle of the electron beam can be made much larger for the same current supply.

The above advantages are due to the fact that the four poles 38 constituting the auxiliary deflection device 22 are arranged in an elliptical shape to generate an asymmetric quadrupole field. That is, since the auxiliary deflection device 22 generates an asymmetric magnetic field, the rate at which magnetic fields cancel each other in the central portion through which the electron beam 10 passes can be greatly reduced, thereby enhancing the influence of the magnetic field on the electron beam. Even with a current supply much smaller than the current, the electron beam can be easily rotated at the desired angle.

3 shows an electron beam shape simulated by applying a current of 8 A to all four poles in a circular deflection device, and the electron beam 10 is rotated approximately 30 ° clockwise with respect to the horizontal axis H. Indicates.

4 shows an electron beam shape simulated by applying a current of 0.2 A to all four magnetic poles 38 in the elliptical auxiliary deflection device 22 according to the present embodiment, and the electron beam 10 has a horizontal axis H. FIG. As a reference, it rotates approximately 40 ° clockwise.

Based on the above simulation results, it can be seen that the present embodiment rotates the electron beam more smoothly with a much smaller current supply than the conventional circular structure.

Next, referring to the rotation angle of the electron beam, FIG. 5 is a schematic view showing one magnetic pole representing the S pole and the other magnetic pole representing the N pole in the circular auxiliary deflection apparatus, and the four magnetic poles are arranged in a circular shape. Accordingly, the magnetic force (B) from the N pole toward the S pole forms an angle of 45 ° with respect to the vertical axis (V), and the Lorentz force (F) forms an angle of 45 ° with respect to the horizontal axis (H).

As a result, the electron beam rotates with the greatest force in the 45 ° direction with respect to the horizontal axis. Even if the current value applied to each magnetic pole is increased, the electron beam rotates in the 45 ° direction instead of increasing the rotation angle of the electron beam.

6 is a schematic view showing the first magnetic pole 38a (S pole) and the third magnetic pole 38c (N pole) in the auxiliary deflection apparatus according to the present embodiment, wherein the horizontal interval between the four magnetic poles is larger than the vertical interval. As it is disposed in an elliptical shape, the magnetic force B from the north pole to the south pole forms an angle of 45 ° or more with respect to the vertical axis (V), and the Lorentz force (F) perpendicular to the magnetic force (B) is based on the horizontal axis (H). To achieve an angle of more than 45 °.

Therefore, since the electron beam 10 passing through the auxiliary deflecting device 22 is subjected to a force on the AA axis forming an angle of 45 ° or more with respect to the horizontal axis, it can be easily rotated at a rotation angle of 45 ° or more with respect to the horizontal axis. .

Here, the auxiliary deflecting device 22 according to the present embodiment takes into consideration that the distance between the pair of magnetic poles facing in the horizontal direction is greater than the distance between the pair of magnetic poles facing in the vertical direction, so that the influence on the electron beam is reduced. It is desirable to supply more current to the pair of magnetic poles facing in the horizontal direction.

As described above, the present embodiment can rotate the electron beam at a rotation angle of 45 ° or more with respect to the horizontal axis by providing an elliptical auxiliary deflection device that is long in the horizontal direction. In another embodiment, the auxiliary deflecting device may further include the third and fourth magnetic poles facing in the vertical direction rather than the distance between the first and second magnetic poles 38a and 38b facing in the horizontal direction. By arranging four magnetic poles so that the distance between 38c, 38d) is large, it can be made into a long oval in the vertical direction.

In both embodiments, the auxiliary deflecting device 22 of the above configuration rotates the electron beam at a larger rotation angle by expanding the influence of the magnetic field on the electron beam incident on the screen periphery to correct the electron beam tilt at the screen periphery. You have to.

That is, the inclination correction circuit section 42 of the auxiliary deflection apparatus 22 generates an input waveform corresponding to the deflection signal of the deflection yoke 14 and applies it to the coil 40. FIG. Fig. 9 shows an input waveform of one period in the vertical direction for one frame scan.

As shown in the figure, as the tilt correction circuit unit 42 deflects the electron beam 10 toward the periphery of the screen, the inclination correction circuit unit 42 can correct the inclination of the electron beam at the periphery of the screen by increasing the rotation angle of the electron beam.

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 present invention is provided with an elliptical auxiliary deflection device to generate an asymmetric magnetic field to enhance the influence of the magnetic field on the electron beam to facilitate the electron beam rotation even with a smaller current supply, and to rotate the electron beam at a larger rotation angle You can. This can effectively improve the electron beam rotation efficiency of the auxiliary deflection device while minimizing the power consumption required to drive the auxiliary deflection device.

Claims (7)

A fluorescent film screen formed on an inner surface of the panel and having an index stripe; An electron gun embedded in the neck portion and emitting an electron beam toward the fluorescent screen; A photo detector provided on an outer surface of the funnel connecting the panel and the neck portion and detecting an index light emitted from the index stripe; An index circuit for synchronizing the index signal provided from the photo detector with a color signal to apply an accurate color signal to the electron gun; A deflection yoke for generating a deflection magnetic field to deflect the electron beam emitted from the electron gun; Beam index type cathode ray which is mounted on the outer circumferential surface of the neck portion and includes four auxiliary poles facing each other in the horizontal and vertical directions of the screen to have an elliptical arrangement to apply an asymmetric quadrupole magnetic field to the electron beam passing through the electron gun. tube. The method of claim 1, The auxiliary deflection device, An elliptical support mounted on an outer circumferential surface of the neck portion; Four magnetic poles fixed to an inner circumferential surface of the support and disposed to face in the horizontal and vertical directions of the screen; A coil which is wound around and fixed to the magnetic poles sequentially; And a slope correction circuit unit connected to both ends of the coil to provide a current to the coil. The method of claim 1, And the auxiliary deflection apparatus is mounted so as to face the focus electrode of the electron gun. The method of claim 2, And a beam index type cathode ray tube arranged such that the distance between the pair of magnetic poles facing each other in the horizontal direction is greater than the distance between the pair of magnetic poles facing in the vertical direction. The method of claim 4, wherein And the slope correction circuit part provides a current larger than a pair of magnetic poles facing in the vertical direction to a pair of magnetic poles facing in the horizontal direction. The method of claim 2, And the distance between the pair of magnetic poles facing each other in the vertical direction is greater than the distance between the pair of magnetic poles facing in the horizontal direction. The method of claim 6, And a slope index circuit part that provides a current larger than a pair of magnetic poles facing in the horizontal direction to a pair of magnetic poles facing in the vertical direction.