JP3807300B2 - Cathode ray tube equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cathode ray tube device such as a television receiver, and more particularly to a geomagnetism correction device used for improving landing deviation of an electron beam due to geomagnetism.
[0002]
[Prior art]
In this specification, the horizontal axis (direction parallel to the long side of the front panel) when the cathode ray tube is placed in a normal use state is the X axis, the vertical axis is the Y axis, the X axis and the Y axis. The axis that intersects the axis at right angles is called the Z axis. Further, “upper”, “lower”, “left”, and “right” are based on the time when the cathode ray tube is viewed from the front panel side unless otherwise specified.
[0003]
In an external magnetic field such as geomagnetism, the electron beam in the cathode ray tube is subjected to electromagnetic force according to Fleming's left-hand rule, the incident angle from the shadow mask to the phosphor screen changes, the landing position changes, and the predetermined phosphor dot A so-called mislanding occurs in which the electron beam does not hit the entire surface or hits an adjacent phosphor dot.
[0004]
FIG. 8 is a diagram showing the direction of deviation of the landing of the electron beam when the cathode ray tube is viewed from the front panel side. FIG. 8A shows the case where the front panel of the cathode ray tube faces north, and the force that the electron beam receives from the geomagnetism is leftward at the upper part of the screen and rightward at the lower part of the screen. FIG. 8B shows the case where the front panel faces east, and the force that the electron beam receives from the geomagnetism is directed to the right at the top left of the screen, to the left at the top right of the screen, to the left at the bottom left of the screen, and to the right at the bottom right of the screen. It is. FIG. 8C shows the case where the front panel faces south, and the force that the electron beam receives from the geomagnetism is directed to the right at the top of the screen and to the left at the bottom of the screen. FIG. 8D shows a case where the front panel faces west, and the force that the electron beam receives from the geomagnetism is leftward at the upper left part of the screen, rightward at the upper right part of the screen, rightward at the lower left part, and leftward at the lower right part. . From the above, when the cathode ray tube is facing north or south, the landing is shifted so that the entire screen is distorted into a parallelogram, and when it is facing east or west, the landing is shifted so that the entire screen is distorted into a trapezoid. become.
[0005]
FIG. 9 and FIG. 10 are graphs showing the relationship between the orientation (front panel orientation) of a cathode ray tube having a deflection angle of 90 ° and the direction and magnitude of the landing deviation of the electron beam. FIG. 9 shows the case of the upper part of the screen, and FIG. 10 shows the case of the lower part of the screen. The horizontal axis of the graph indicates the orientation of the cathode ray tube, where 0 ° is north, 90 ° is east, 180 ° is south, and 270 ° is west (the same applies hereinafter). The vertical axis indicates the magnitude of the landing deviation. When the value is positive, it indicates rightward movement, and when the value is negative, it indicates leftward movement.
[0006]
In FIG. 9, the landing deviation at the upper right of the screen (curve 9a), the landing deviation at the upper left (curve 9b), and the landing deviation at the center (dashed curve 9c) all change according to the sine wave sin (θ-α). In the case of 90 ° deflection, since the electron beam is deflected by ± 45 ° in the horizontal direction with respect to the Z axis, a phase difference of about 90 ° occurs between the upper right end and the upper left end. Α in the previous equation is 135 ° for the curve 9a, 45 ° for the curve 9b, and 90 ° for the curve 9c. In the case of the lower portion of the screen shown in FIG. 10, the lower right corner of the screen (curve 10a), the lower left portion of the screen (curve 10b), and the lower middle portion of the screen (dashed curve 10c) indicate whether the curves 9a, 9b, and 9c in FIG. Inverted form.
[0007]
FIG. 11 is a schematic diagram of a geomagnetism correction device conventionally used in some television receivers in order to correct a landing shift due to geomagnetism. Four X coils 101 are provided at four corners on the back surface (cone portion) of the funnel 22 of the cathode ray tube, and one Z coil 102 is provided so as to surround the entire funnel 22. An X-coil magnetic orientation sensor 103 for sensing geomagnetism in the X-axis direction is provided in a direction parallel to the X-axis, and a Z-coil magnetic orientation sensor 104 for sensing geomagnetism in the Z-axis direction is parallel to the Z-axis. It is provided in various directions. Both sensors are shown in the shape of arrows, and the direction of the arrows indicates that a positive output signal is generated with respect to the magnetic field in that direction.
[0008]
The output voltage of the X-coil magnetic orientation sensor 103 is converted into a current by the X coil drive circuit 105, and this current is supplied to the X coil 101. The output voltage of the Z-coil magnetic orientation sensor 104 is converted into a current by the Z-coil drive circuit 106, and this current is supplied to the Z coil 102. Of the four X coils 101, the upper and lower two on the left side generate magnetic fields in the same direction, the upper and lower two on the right side generate magnetic fields in the same direction, and the left and right coils generate magnetic fields in opposite directions. To be connected.
[0009]
FIG. 12 is a graph showing the relationship between the orientation of the cathode ray tube, the output of the X-coil magnetic orientation sensor 103 (curve 12a), and the output of the Z-coil magnetic orientation sensor 104 (curve 12b). The output 12a of the X-coil magnetic direction sensor 103 is represented by a sine wave sin θ that generates a peak output when the cathode ray tube faces in the east-west direction. The output 12b of the Z-coil magnetic azimuth sensor 104 is represented by a negative cosine wave −cos θ that generates a peak output when the cathode ray tube faces in the north-south direction.
[0010]
FIG. 13 shows the relationship between the orientation of the cathode ray tube and the value (relative value) of the correction magnetic field generated by the X coil and Z coil at each part of the screen. A positive value indicates a magnetic field that corrects a right landing deviation, and a negative value indicates a magnetic field that corrects a left landing deviation. In the upper left and right of the screen (curve 13a), it is represented by the sum sin (θ−α) of the magnetic field of the Z coil and the magnetic field of the X coil. In the upper right and lower sides of the screen (curve 13b), it is represented by a difference −sin (θ + α) between the magnetic field of the Z coil and the magnetic field of the X coil. At the top and bottom of the screen (dashed curve 13c), the magnetic field -cos θ of the Z coil is dominant.
[0011]
When the correction magnetic field shown in FIG. 13 and the landing deviation shown in FIG. 9 are compared, the phases are the same at the upper right, upper center, and upper left of the screen. That is, the landing correction by the correction magnetic field has the same phase and the opposite direction as the landing deviation shown in FIG. On the other hand, in the lower part of the screen, the Y-axis direction component of the electron beam current is opposite to the upper part of the screen, so that the landing moving direction is reversed even if a correction magnetic field having the same direction as the upper part of the screen is applied. That is, the landing correction by the correction magnetic field has the same phase as the landing deviation in FIG. 10 and the opposite direction, and cancels each other.
[0012]
In the case of a wide-angle cathode ray tube of 90 ° or more, for example, 110 °, the electron beam is deflected by ± 55 ° in the horizontal direction with reference to the Z axis. Is a phase difference of 180 ° −110 ° = 70 °. On the other hand, the magnetic direction sensor for Z coil and the magnetic direction sensor for X coil have a phase difference of 90 ° and do not coincide with the phase difference of 70 ° of landing deviation, so α = (180 ° −110 °) / 2 = 35. The output voltage amplitude ratio of the two sensors is set to 0.7 so that ° = tan-1 (Az / Ax).
[0013]
[Problems to be solved by the invention]
In the conventional geomagnetism correction device, regardless of the deflection angle of the cathode ray tube, the geomagnetism is separated and detected into the Z-axis direction component and the X-axis direction component, and the current converted by the drive circuit is passed through the Z coil and X coil. The magnetic field generated by each coil was synthesized over the entire screen area. For this reason, in a state where the cathode ray tube is placed in an arbitrary direction, it is difficult to specify the amount of each magnetic field of the X coil and the Z coil that contributes to the landing correction. There was a problem that it was difficult to specify the required output of the circuit. Therefore, the adjustment of the correction amount is performed by adjusting the correction amount of the Z coil in the geomagnetism in the Z axis direction where the output of the magnetic sensor for X coil becomes zero, and the output of the magnetic direction sensor for Z coil becomes zero. The correction amount of the X coil was adjusted in the geomagnetism of the direction. One sensor output is zero and only one coil generates a correction magnetic field, and the correction amount must be individually adjusted for each sensor, and the adjustment work is complicated.
[0014]
Further, in the conventional configuration, a total of five correction coils of four X coils and one Z coil are required.
[0015]
The present invention solves such a problem, and provides a cathode ray tube device including a geomagnetic correction device in which five conventional coils are replaced with four coils and the correction amount can be adjusted only once. Is.
[0016]
[Means for Solving the Problems]
According to the first aspect of the present invention, the panel and the funnel constitute an envelope, a phosphor surface is formed on the inner surface of the panel, a color selection electrode is provided opposite to the phosphor surface, and the neck of the funnel A cathode ray tube having an electron gun in the unit, four correction coils arranged symmetrically with respect to the X-axis and Y-axis of the cathode-ray tube on the side surface or the back side of the cathode ray tube, and components in two different directions of the external magnetic field And a drive circuit that converts an output signal of the magnetic orientation sensor into a current that flows through the correction coil, and the correction coil is configured to detect the cathode ray tube when viewed from behind. The first correction coil located in the upper left part, the second correction coil located in the lower left part, the third correction coil located in the upper right part, and the fourth correction coil located in the lower right part, Above One correction coil and the third correction coil partially overlap on the Y axis, and the second correction coil and the fourth correction coil partially overlap on the Y axis. It is characterized by.
[0017]
According to this configuration, the magnetic fields of the left and right correction coils contribute to the correction of the left and right areas of the screen, respectively, and the combined magnetic field of the portion where the left and right coils overlap contributes to the correction of the center upper and lower parts of the screen. Moreover, the conventional Z coil becomes unnecessary and the number of coils can be made four.
[0018]
According to a second aspect of the present invention, the first correction coil and the second correction coil generate a magnetic field in the same direction with respect to the cathode ray tube, and the third coil and the fourth coil Generates a magnetic field in the same direction with respect to the cathode ray tube, and the first correction coil and the second correction coil, and the third correction coil and the fourth correction coil are independent of each other. Is generated.
[0019]
With this configuration, since the magnetic fields generated by the upper and lower coils are in the same direction, the force exerted on the electron beam by the magnetic field is reversed between the upper part and the lower part of the screen, thereby correcting mislanding in the upper and lower parts of the screen.
[0020]
According to a third aspect of the present invention, the first correction coil and the second correction coil are connected in series, the third correction coil and the fourth correction coil are connected in series, The drive circuit includes a first drive circuit that supplies current to the first correction coil and the second correction coil, and a second drive circuit that supplies current to the third correction coil and the fourth correction coil. And a drive circuit.
[0021]
With this configuration, the first correction coil and the second correction coil, and the third correction coil and the fourth correction coil can generate magnetic fields independently of each other. Two drive circuits are sufficient.
[0022]
According to a fourth aspect of the present invention, the first to fourth correction coils are substantially elliptical and are arranged so that the major axis direction thereof is substantially parallel to the X axis.
[0023]
With this configuration, the first correction coil or the second correction coil and the third correction coil or the fourth correction coil can be easily overlapped on the Y axis.
[0024]
According to a fifth aspect of the present invention, the magnetic azimuth sensor includes a first sensor and a second sensor, and the first sensor is maximally deflected rightward in the X-axis direction when viewed from the panel side. The second sensor is arranged so that the highest sensitivity can be obtained in a direction substantially perpendicular to a straight line parallel to the trajectory of the electron beam at the time when the electron beam is deflected. It is arranged so that the highest sensitivity can be obtained in a direction substantially perpendicular to a straight line parallel to the orbit.
[0025]
According to this configuration, the magnetic azimuth sensor is installed so as to have a sensitivity peak in a direction perpendicular to the electron beam trajectory at the time of deflection on the left and right of the screen, and the landing deviation of the electron beam in all directions of the cathode ray tube and the output of the magnetic azimuth sensor Can be made similar.
[0026]
According to a sixth aspect of the present invention, the first sensor is parallel to the longitudinal direction of the first sensor and the trajectory of the electron beam when the horizontal deflection amount is deflected to the right in the X-axis direction from the panel side. The second sensor is arranged so that a straight line and the straight line parallel to the trajectory of the electron beam when deflected to the left in the X-axis direction are almost perpendicular. Are arranged in such a way.
[0027]
With this configuration, the first and second sensors can obtain the highest sensitivity in a direction substantially perpendicular to the trajectory of the electron beam at the time of maximum deflection in the X-axis direction.
[0028]
According to a seventh aspect of the present invention, the first sensor and the second sensor are arranged on a plane that intersects with the Y axis at a right angle.
[0029]
With this configuration, the X-axis direction component and the Z-axis direction component of geomagnetism can be detected efficiently.
[0030]
According to an eighth aspect of the present invention, an angle formed between the longitudinal direction of the first sensor and the Z axis and an angle formed between the longitudinal direction of the second sensor and the Z axis are 30 ° or more and 60 ° or less, respectively. It is.
[0031]
With this configuration, landing deviation due to geomagnetism can be corrected with a cathode ray tube having a maximum deflection angle of 60 ° to 120 ° in the horizontal direction.
[0032]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings.
[0033]
FIG. 2 is a schematic view of the cathode ray tube apparatus of the present invention. In the cathode ray tube 21, a panel (not shown) and a funnel 22 constitute an envelope, a phosphor surface (not shown) is formed on the inner surface of the panel, and a color selection electrode (not shown) is opposed to the phosphor surface. And an electron gun (not shown) is provided in the neck portion 23 of the funnel 22. The back surface portion (cone portion) of the funnel 22 includes four correction coils 1 to 4 arranged symmetrically with respect to the X axis and the Y axis. The cabinet 24 includes a circuit board 25 having a magnetic direction sensor 5 and a drive circuit 11 that converts an output signal of the magnetic direction sensor 5 into a current that flows through the correction coils 1 to 4.
[0034]
FIG. 1 is a diagram showing an outline of the configuration of a geomagnetic correction device in the cathode ray tube device of the present invention. Four correction coils 1 to 4 are disposed on the back surface of the funnel 22 and are approximately symmetrical with respect to the X-axis and the Y-axis of the cathode ray tube. The correction coils 1 to 4 include a first correction coil 1 disposed at the upper left portion of the funnel 22 as viewed from the back (electron gun side), a second correction coil 2 disposed at the lower left portion, and an upper right portion. It consists of a third correction coil 3 arranged and a fourth correction coil 4 arranged in the lower right part. The correction coils 1 to 4 generate a magnetic field having at least an X-axis direction component and a Z-axis direction component.
[0035]
The first to fourth correction coils 1 to 4 are substantially elliptical and are arranged so that the major axis direction thereof is substantially parallel to the X axis. As shown in FIGS. 1 and 3, the first correction coil 1 and the third correction coil 3 partially overlap on the Y axis. The second correction coil 2 and the fourth correction coil 4 also partially overlap on the Y axis. In the overlapping portion, a magnetic field is generated by adding the magnetic fields generated by the two coils. As will be described later, this portion mainly corrects the vertical landing deviation at the center of the screen.
[0036]
The magnetic azimuth sensor 5 is arranged so as to sense at least the X-axis direction component and the Z-axis direction component of geomagnetism, but is preferably arranged on a plane that intersects at right angles to the Y-axis. The magnetic azimuth sensor 5 includes a first sensor 6 and a second sensor 7 that respectively sense two different components of the external magnetic field in a plane perpendicular to the Y axis. Each sensor is indicated by a white arrow as in FIG. The “CRT direction” indicated by an arrow indicates the direction of the front panel.
[0037]
The first sensor 6 is arranged so that maximum sensitivity is obtained when it is placed in a predetermined direction. The direction is such that the vertical deflection amount is zero and the horizontal deflection amount is substantially perpendicular to the extension line of the electron beam trajectory when the horizontal deflection amount is maximally deflected to the right in the X-axis direction when viewed from the panel side. is there. On the other hand, the second sensor 7 is also arranged so as to obtain the maximum sensitivity when placed in a predetermined direction. The direction is a direction that is substantially perpendicular to the extended line of the orbit of the electron beam when deflected to the left in the X-axis direction to the maximum.
[0038]
When the magnetic azimuth sensor 5 is composed of two solenoid coils, as shown in FIG. 4, each longitudinal direction (direction parallel to the central axis) and extension lines 41 and 42 of the electron beam trajectory are substantially perpendicular to each other. It arrange | positions on the board | substrate 43 so that. The first sensor 6 is disposed so as to be perpendicular to a straight line 41 parallel to the trajectory of the electron beam when deflected to the maximum in the X-axis direction right side (left side in FIG. 4) when viewed from the panel side. The second sensor 7 is disposed so as to form a right angle with a straight line 42 parallel to the trajectory of the electron beam when deflected to the left in the X-axis direction when viewed from the panel side. When the deflection angle β of the cathode ray tube is 90 °, the first sensor 6 and the second sensor 7 are arranged so that the angle γ formed by the longitudinal direction of the first sensor 6 and the second sensor 7 is 45 °.
[0039]
The drive circuit 11 converts the output voltage signal of the magnetic direction sensor 5 into a current and supplies it to the first to fourth correction coils 1 to 4. The drive circuit 11 includes a first drive circuit 12 that supplies current to the first correction coil 1 and the second correction coil 2, and a first drive circuit that supplies current to the third correction coil 3 and the fourth correction coil 4. 2 drive circuits 13.
[0040]
Among the four coils, the first correction coil 1 and the second correction coil 2 are connected in series, and the third correction coil 3 and the fourth correction coil 4 are connected in series. The first correction coil 1 and the second correction coil 2 generate a magnetic field in the same direction with respect to the cathode ray tube. The third correction coil 3 and the fourth correction coil 4 generate a magnetic field in the same direction with respect to the cathode ray tube. Further, the first correction coil 1 and the second correction coil 2, and the third correction coil 3 and the fourth correction coil 4 generate magnetic fields independently of each other.
[0041]
Next, the principle of correcting the landing deviation by the geomagnetic correction device according to the present invention will be described.
[0042]
FIG. 5 shows the orientation of the cathode ray tube, the output voltage of the first sensor 6 (curve 5a), the output voltage of the second sensor 7 (curve 5b), and the sum of the output voltages of both sensors (dashed curve 5c). It is a graph which shows a relationship.
[0043]
In FIG. 5, the output voltage of the first sensor 6 is positive when the orientation of the cathode ray tube is in the range of 135 ° to 315 °. At this time, the polarities of the first correction coil 1 and the second correction coil 2 are set so that the first correction coil 1 and the second correction coil 2 generate a magnetic field that corrects the landing deviation in the right part of the screen. It has been decided. When the azimuth is in the range of 315 ° to 135 °, the output voltage is negative, and the direction of the magnetic field generated by the first correction coil 1 and the second correction coil 2 is opposite to that in the case of 135 ° to 315 °. become. The first correction coil 1 and the second correction coil 2 generate a magnetic field that changes in phase with the output voltage of the first sensor 6.
[0044]
On the other hand, the output voltage of the second sensor 7 is positive when the orientation of the cathode ray tube is in the range of 45 ° to 225 °. At this time, the polarities of the third correction coil 3 and the fourth correction coil 4 are set so that the third correction coil 3 and the fourth correction coil 4 generate a magnetic field for correcting the landing deviation in the left part of the screen. It has been decided. When the azimuth is in the range of 225 ° to 45 °, the output voltage is negative, and the direction of the magnetic field generated by the third correction coil 3 and the fourth correction coil 4 is opposite to the case of 45 ° to 225 °. become. The third correction coil 3 and the fourth correction coil 4 generate a magnetic field that changes in phase with the output voltage of the second sensor 7.
[0045]
The sum of the output voltages of both sensors (curve 5c) is a curve that takes a peak value when the direction is 0 ° and 180 °, that is, when the cathode ray tube is placed in the north-south direction.
[0046]
FIG. 6 is a graph showing the relationship between the orientation of the cathode ray tube and the landing correction amount at the top of the screen due to the magnetic field generated by the first correction coil 1 and the third correction coil 3. Compared with FIG. 5, it can be seen that the change in the landing correction amount (curve 6a) at the upper right of the screen changes in proportion to the output of the first sensor 6, that is, the magnetic field generated by the first correction coil 1. Similarly, the change in the landing correction amount (curve 6b) at the upper left of the screen changes in proportion to the output of the second sensor 7, that is, the magnetic field generated by the third correction coil 3. The change in the landing correction amount (curve 6c) on the center of the screen changes in proportion to the sum of the outputs of both sensors, that is, the combined magnetic field generated by the first correction coil 1 and the third correction coil 3.
[0047]
When the landing correction curve at the top of the screen shown in FIG. 6 and the landing deviation curve at the top of the screen due to geomagnetism shown in FIG. 9 are compared, the sign is inverted for each of the top right, top left, and top center of the screen. You can see that That is, of the landing deviation due to geomagnetism, the upper right of the screen is canceled by the landing correction by the magnetic field of the first correction coil 1, and the upper left of the screen is canceled by the landing correction by the magnetic field of the third correction coil 3, and the upper center of the screen Is canceled by the landing correction by the combined magnetic field of the first correction coil 1 and the third correction coil 3.
[0048]
For the lower part of the screen, the landing deviation due to geomagnetism is the reverse of the landing deviation at the upper part of the screen. The direction of the magnetic field generated by the second correction coil 2 is the same as the direction of the magnetic field generated by the first correction coil 1, and the direction of the magnetic field generated by the fourth correction coil 4 is determined by the third correction coil 3. The direction of the generated magnetic field is the same. On the other hand, since the Y-axis direction component of the electron beam is opposite to that in the upper part of the screen, the landing correction amount is obtained by inverting the positive and negative of the curve shown in FIG. As a result, the landing deviation due to the terrestrial magnetism is canceled by the landing correction by the magnetic field of the second correction coil 2 and the fourth correction coil 4 in the lower part of the screen as in the upper part of the screen.
[0049]
(Example)
Next, examples in which the effects of the present invention have been confirmed will be described. In the experiment, a cathode ray tube of 68 cm (29 inches) with a deflection angle of 90 ° was used.
[0050]
As shown in FIG. 3, the first correction coil 1 (or the second correction coil 2) and the third correction coil 3 (or the fourth correction coil 4) used in the present embodiment have a minor axis of 150 mm, It is an ellipse with a major axis of 300 mm and is wound 50 times with an enameled copper wire of 0.32 mmφ. The two coils overlap each other up to about 150 mm in the major axis direction.
[0051]
Sony Corporation MIU-212 was used for the magnetic orientation sensor. As shown in FIG. 4, the sensor was installed so that the angle γ formed by the Z axis and the longitudinal direction of each sensor was 45 °.
[0052]
The first drive circuit 12 and the second drive circuit 13 are each a voltage-current conversion circuit. The first drive circuit 12 and the second drive circuit 13 set the gain so that a current of 30 mA flows through the corresponding coil when the outputs of the first sensor 6 and the second sensor 7 are maximized, respectively. did.
[0053]
FIG. 7 shows the result of correcting the landing deviation during geomagnetism (30 μT) in Japan using the geomagnetism correcting apparatus having the above configuration. FIG. 7A shows the case where the cathode ray tube faces north, and FIG. 7B shows the case where it faces east. The landing deviation was limited to 7 μm (leftward) at the maximum.
[0054]
In the above, a case where a cathode ray tube having a deflection angle of 90 ° is used and two sensors are used in an orthogonal direction has been described. However, the present invention can cope with cathode ray tubes having various deflection angles by changing the relative angles of the two sensors. In FIG. 4, for example, in the case of 100 ° deflection (β = 100 °), the angle γ is (180 ° −100 °) / 2 = 40 °, and in the case of 110 ° deflection, the angle γ is (180 ° − 110 °) / 2 = 35 °. By changing the angle γ in the range of 60 ° to 30 °, it becomes possible to deal with a cathode ray tube whose deflection angle β is in the range of 60 ° to 120 °.
[0055]
The correction amount can be adjusted by adjusting the correction amounts on the left and right sides of the screen with the cathode ray tube facing north (0 °), east (90 °), south (180 °), and west (270 °). Well, it is not necessary to make the adjustment twice by changing the direction of the cathode ray tube as in the prior art. This is because the influence of the magnetic field of the first and second correction coils is dominant on the right side of the screen, and the influence of the magnetic field of the third and fourth correction coils is dominant on the left side of the screen. This is because it is not necessary to separate the influence of both coils by making the correction magnetic field of the coil zero. Ideally, the azimuth of the cathode ray tube is set to 45 ° or 225 ° to adjust the correction amount by the first and second correction coils, and the third and fourth azimuths at the azimuth of 135 ° or 315 ° are adjusted. It is preferable to adjust the correction amount by the correction coil. This is because, as shown in FIG. 5, the output of the magnetic azimuth sensor takes a peak value in each azimuth, so that the adjustment error becomes relatively small. However, as described above, even in the directions of 0 °, 90 °, 180 °, and 270 °, the output of the magnetic direction sensor takes a value close to the peak value, so that the adjustment error can be reduced.
[0056]
The example in which the four correction coils are arranged along the back surface of the funnel of the cathode ray tube has been described above. However, there are other correction coil arrangements that generate a magnetic field for correcting the landing movement in the X-axis direction on the screen. Various things are possible. As long as the direction of the magnetic field generated by the correction coil is not parallel to the trajectory of the electron beam deflected left and right, a force for moving the electron beam is generated. For example, the correction coil is arranged in a plane perpendicular to the Z axis, the correction coil is arranged on the upper surface portion and the lower surface portion of the cathode ray tube, or the left end portion of the left correction coil and the right end portion of the right correction coil. Are extended to the left and right side portions of the cathode ray tube, and the upper end portion of the upper correction coil and the lower end portion of the lower correction coil are extended to the upper surface portion and the lower surface portion of the cathode ray tube, respectively. be able to.
[0057]
【The invention's effect】
As described above, according to the present invention, the landing deviation of the electron beam in all directions of the cathode ray tube and the output of the magnetic direction sensor can be in phase, and the effects of the left and right coils on the screen can be separated.
[0058]
Further, there is an advantageous effect that the gains of the left and right drive circuits can be adjusted simultaneously when the cathode ray tube is oriented in either the east-west direction or the north-south direction.
[0059]
Further, according to the present invention, by using the magnetic azimuth sensor at an angle of ± 30 ° to ± 60 ° symmetrically with respect to the cathode ray tube axis (Z axis) on the horizontal plane, the maximum deflection angle is from 60 ° to 120 ° horizontally. Landing shift due to geomagnetism can be corrected with this cathode ray tube.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of a geomagnetic correction device in a cathode ray tube device of the present invention.
FIG. 2 is a schematic view of a cathode ray tube apparatus of the present invention.
FIG. 3 is a diagram showing a correction coil according to the present invention.
FIG. 4 is a diagram showing a magnetic orientation sensor according to the present invention.
FIG. 5 is a diagram showing the relationship between the orientation of a cathode ray tube and the output of a magnetic orientation sensor in the present invention.
FIG. 6 is a diagram showing the relationship between the orientation of the cathode ray tube and the landing correction amount in the present invention.
FIG. 7 is a diagram showing a result of correction of landing deviation in the present invention;
(A) is a diagram showing the case where the cathode ray tube faces north
(B) is a diagram showing a case where the cathode ray tube faces east.
FIG. 8 is a graph showing electron beam landing characteristics due to geomagnetism in a cathode ray tube;
FIG. 9 is a diagram showing the relationship between the orientation of a 90 ° -deflected cathode ray tube and landing deviation at the top of the screen.
FIG. 10 is a diagram showing the relationship between the orientation of a 90 ° deflection cathode ray tube and the landing deviation at the bottom of the screen.
FIG. 11 is a schematic diagram of a conventional geomagnetic correction device.
FIG. 12 is a diagram showing the relationship between the direction of the cathode ray tube and the sensor output voltage in a conventional geomagnetic correction device;
FIG. 13 is a diagram showing the relationship between the direction of a cathode ray tube and a correction magnetic field in a conventional geomagnetic correction apparatus.
[Explanation of symbols]
1 First correction coil
2 Second correction coil
3 Third correction coil
4th correction coil
5 Magnetic direction sensor
6 First sensor
7 Second sensor
11 Drive circuit
12 First drive circuit
13 Second drive circuit
21 Cathode ray tube
22 Funnel

Claims (8)

A cathode ray tube comprising a panel and a funnel forming an envelope, a phosphor surface formed on an inner surface of the panel, a color selection electrode provided opposite to the phosphor surface, and an electron gun provided in a neck portion of the funnel; ,
Four correction coils arranged symmetrically with respect to the X-axis and Y-axis of the cathode-ray tube on the side surface or the back surface of the cathode-ray tube;
A magnetic azimuth sensor for sensing components in two different directions of the external magnetic field;
A drive circuit that converts an output signal of the magnetic orientation sensor into a current that flows through the correction coil;
The correction coil includes a first correction coil located in the upper left portion of the cathode ray tube, a second correction coil located in the lower left portion, and a third position located in the upper right portion when the cathode ray tube is viewed from behind. And a fourth correction coil located at the lower right,
The first correction coil and the third correction coil partially overlap each other on the Y axis, and the second correction coil and the fourth correction coil partially overlap each other on the Y axis. A cathode ray tube device characterized by comprising: The first correction coil and the second correction coil generate a magnetic field in the same direction with respect to the cathode ray tube, and the third coil and the fourth coil have the same direction with respect to the cathode ray tube. Generates a magnetic field of
2. The cathode ray tube apparatus according to claim 1, wherein the first correction coil and the second correction coil, and the third correction coil and the fourth correction coil generate magnetic fields independently of each other. The first correction coil and the second correction coil are connected in series, the third correction coil and the fourth correction coil are connected in series,
The drive circuit includes a first drive circuit that supplies current to the first correction coil and the second correction coil, and a second that supplies current to the third correction coil and the fourth correction coil. The cathode-ray tube apparatus according to claim 2, further comprising: 4. The cathode ray tube apparatus according to claim 3, wherein the first to fourth correction coils are substantially elliptical and are arranged such that a major axis direction thereof is substantially parallel to the X axis. The magnetic direction sensor has a first sensor and a second sensor,
The first sensor is arranged so as to obtain the highest sensitivity in a direction substantially perpendicular to a straight line parallel to the trajectory of the electron beam when deflected to the right in the X-axis direction when viewed from the panel side.
The second sensor is also arranged so as to obtain the highest sensitivity in a direction substantially perpendicular to a straight line parallel to the trajectory of the electron beam when deflected to the left in the X-axis direction. 5. The cathode ray tube device according to any one of 4 above. In the first sensor, the longitudinal direction thereof and the straight line parallel to the trajectory of the electron beam when the horizontal deflection amount is deflected to the right in the X-axis direction from the panel side are substantially perpendicular to each other. Arranged,
6. The second sensor according to claim 5, wherein the second sensor is arranged such that a longitudinal direction thereof and a straight line parallel to the trajectory of the electron beam when deflected to the left in the X-axis direction are substantially perpendicular to each other. Cathode ray tube device. The cathode-ray tube apparatus according to claim 6, wherein the first sensor and the second sensor are arranged on a plane that intersects with the Y axis at a right angle. The angle formed by the longitudinal direction of the first sensor and the Z axis and the angle formed by the longitudinal direction of the second sensor and the Z axis are 30 ° or more and 60 ° or less, respectively. Cathode ray tube device.

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