JPH0461590A - Magnetic field correction device for color cathode ray tube device - Google Patents

Abstract

PURPOSE:To correspond to detected magnetic field strength and to correct mis-landing continuously with respect to an azimuth by calculating an earth magnetism correction data and supplying a correction current to a correction coil from a drive circuit based on the calculated value so as to generate a correction magnetic field. CONSTITUTION:A magnetic azimuth sensor 10 is of flux gate type and a sinusoidal wave signal S1 and a cosine signal S2 are obtained with comparatively high sensitivity and high accuracy. Then a sinusoidal wave signal S1E and a cosine signal S2E are outputted from a magnetic azimuth sensor signal processing section 12 and the sinusoidal wave signal S1E and the cosine signal S2E are inputted respectively to a low pass filter (LPF) 14. Then correction signals S5,S6 are obtained from an adder subtractor circuit 16. The correction signals S5,S6 are is fed to correction coils 34-39 connected to a drive circuit 20 via a matrix circuit 18 together with the sinusoidal wave signal S1E.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a magnetic field correction device for a color cathode ray tube that is suitable for, for example, correcting mislandish ink.

[Summary of the invention]

The present invention relates to a magnetic field correction device for a color cathode ray tube that is suitable for use in correcting mislandish ink, for example, and in a magnetic field correcting device for a color cathode ray tube that corrects mislandish ink in a color cathode ray tube equipped with a color selection mask. It has a sensor, a calculation section, a drive circuit, and a correction coil.The magnetic magnetic sensor detects earth's magnetism, and the calculation section calculates geomagnetic correction data and supplies it to the drive circuit, and sends a correction current to the correction coil. By flowing the magnetic field and generating a correction magnetic field, it corresponds to the detected magnetic field strength and corrects continuous misland ink with respect to orientation, and also corrects misland ink of various color cathode ray tubes. It has been made possible.

[Conventional technology]

Conventionally, in a color cathode ray tube or the like using a color selection mask used in a color receiver, the electron beam may be displaced due to the influence of the earth's magnetism and may not reach a predetermined position of the phosphor. In other words, misland ink occurs and color utility is affected.
deteriorates. In particular, in the case of high-definition large color cathode ray tubes, the deterioration in color visibility is remarkable. For this purpose, a landing correction coil is installed in the funnel section of the color cathode ray tube, and a current corresponding to the measured geomagnetism value is passed through the coil, and the magnetic field generated here corrects the trajectory of the electron beam. Correction is made to compensate for the deterioration in color beauty.

As such a landing correction means, a geomagnetism detection device for a color television receiver (Japanese Patent Application Laid-Open No. 5247321) using a magnetic field detection coil for detecting the geomagnetism has been proposed.

[Problem to be solved by the invention]

However, in the conventional geomagnetism detection device for a color television receiver, characteristic errors are likely to occur between the two magnetic field detection coils employed.

For this reason, it is difficult to detect the earth's magnetic field with high precision, and there is a possibility that it is difficult to compensate for misland ink with high precision. Furthermore, a geomagnetic detection device must be manufactured to suit the characteristics of each device, resulting in a lack of versatility.

In view of the above-mentioned problems, an object of the present invention is to provide a magnetic field correction device for a color cathode ray tube, which corresponds to the detected magnetic field strength and continuously corrects the misland ink with respect to the direction, thereby improving its versatility. shall be.

(Means for Solving the Problem) The present invention provides a misland correction device for a color cathode ray tube (30) equipped with a color selection mask, as shown in the magnetic field correction device for a color cathode ray tube (30) shown in FIGS. 1 to 10, for example. A magnetic field correction device for a color cathode ray tube that corrects ink includes a magnetic sensor (10), a calculation unit (16), and a drive circuit (2).
0) and correction coils (34) (35) (36) (3
7) (38) and (39), the magnetic magnetic sensor (10) detects geomagnetism, the calculation unit (16) calculates geomagnetic correction data and supplies it to the drive circuit (20),
Correction coil (34) (35) (36) (37)
(38) A correction current is caused to flow through (39) to generate a correction magnetic field.

[Effect]

According to the magnetic field correction device for a color cathode ray tube of the present invention, the arithmetic unit (1G) calculates geomagnetic correction data from the value of the earth's magnetic field detected by the magnetomagnetic sensor (10), and based on this calculated value, the drive From the circuit (20) to the correction coil (
34) (35) (36) (37) (38) (
39) to generate a correction magnetic field by flowing a correction current.

As a result, the misland ink is corrected in accordance with the detected magnetic field strength and continuously with respect to the orientation.

[Example] Hereinafter, an example of the magnetic field correction device for a color cathode ray tube of the present invention will be described in detail with reference to the drawings.

In FIG. 1, for example, a fluxgate type Lumi 1 energy position sensor (10) for detecting the earth's magnetic field is provided in a television receiver. In this case, it is placed at the bottom of the chassis to avoid the influence of magnetic fields generated by internal circuits, etc., and to effectively detect earth's magnetism. This magnetic orientation sensor (10) has a well-known configuration including a drive coil to which an alternating current is applied to a permalloying core, and two detection coils orthogonal to each other. This magnetic azimuth sensor (10) is arranged horizontally and detects earth's magnetism by utilizing magnetic saturation when a magnetic field passes through two detection coils in orthogonal directions. FIG. 2 shows the output waveform from the magnetic orientation sensor (10). From the two detection coils, a sine wave (sin θ) signal S1 and a cosine wave (cos
θ) signal S2 is output. Here, the azimuth angle (θ) is expressed by the well-known formula (1) below, where EX is the phase of the sine wave signal SI, and EY is the phase of the cosine wave signal S2.

jan-' (EY/EX)
-(1) Furthermore, along with the azimuth angle (θ), the amplitude value becomes a value corresponding to the magnetic field strength of the earth's magnetism to be detected.

FIG. 3 shows a curve of drift of an electron beam due to the influence of earth's magnetism on a color cathode ray tube when correcting misland ink using a sine wave signal SI and a cosine wave signal St.

Afterwards, we will correct each of these drift curves, that is,
Corrections will be made for Mithrande Ink. This example is 9
This is a drift curve due to the influence of geomagnetism in a 0 degree deflection color cathode ray tube, and it is 5 inches (θ) in 4 directions (E, , S, WXN) on the screen Y axis shown in Figure 3A.
, and, for example, the displacement becomes a curve with a maximum value of 30 μm. Below the screen Y axis shown in Figure 3B - (minus) 5
in(θ), and 5in(θ+α) at the top left of the screen shown in Figure 3C, and -5i at the bottom left of the screen shown in Figure 3.
n(θ+α), 5in(θ
-α), and 5 inches (θ-α) at the bottom right of the screen shown in Figure 3F.
The curve becomes

Furthermore, a magnetic orientation sensor signal processing section (12) connected to the magnetic orientation sensor (10) is provided.

The magnetic orientation sensor signal processing unit (12) includes a transmitting unit that generates and sends an AC signal to be supplied to the drive coil of the magnetic orientation sensor (10), a sine wave signal SI, a cosine wave signal S
This is a well-known configuration comprising two systems of phase detection circuits, an integration circuit, a DC amplification circuit, etc., to which AC signals from the transmission section 2 and the transmission section are supplied. Here, a sine wave signal SIE having a voltage of 5 inches (θ) and a cosine wave signal SZE having a voltage of cos (θ) corresponding to the sine wave signal S1 and the cosine wave signal S2 are generated and output.

The sine wave signal SIE and the cosine wave signal S2E are each input to a low pass filter (LPF>(14)), where superimposed unnecessary waves, such as an AC signal supplied to the drive coil, are removed and the frequency is adjusted. Adverse effects with similar horizontal deflection frequency signals, ie, mixing of beat signals, etc., are prevented.

The sine wave signal SIE and cosine wave signal SzE that have passed through this low-pass filter (LPF) (14) are sent to an addition/subtraction circuit (16).
supplied to

The addition/subtraction circuit (16) receives the sine wave signal SIE and the cosine wave signal S.
From the EE, signals corresponding to the drift curves of the Misland ink shown in FIGS. 3A to 3F are generated.

FIG. 4 shows the addition/subtraction circuit (16) in detail. Here, the sine wave signal SIE is output as is, and the sine wave signal S and the d cosine wave signal SEE are simultaneously input to the addition circuit (16a) and subtraction circuit (16b), respectively. At this time, the cosine wave signal SEE is adjusted by the variable resistor V B 16,
The signal is supplied to an addition circuit (16a) and a subtraction circuit (16b), which generate the following correction signal S5 and correction signal S6.

3, E: 5in(θ) −
(2) 35:5in(θ) +cos(θ)=n
s in (fl + a) − (3) S,
: 5in (θ) + CO direct θ) = J loco, "5in (θ - α) ... (4) The value α here must be the same as the value α of the geomagnetic drift curve shown in Figure 3. Of course, the addition circuit (16a) is shown in detail in FIG.
a) combines the sine wave signal SIE and the cosine wave signal SEE through the resistors R, , R, and further connects the operational amplifier (17).
It is amplified by Note that the subtraction circuit (16b) may be configured by providing a phase inversion circuit to which the cosine wave signal siE is supplied to the addition circuit (16a). Also operational amplifier (1
The capacitor C connected to the input and output terminals of 7) operates equivalent to a low-pass filter (14). obtained here,
Sine wave signal SIE, correction signal S, and correction signal S6
is supplied to the matrix circuit (18). here,
Temperature compensation is performed by supplying a signal that detects the temperature. Further, a signal is generated in which the phases of the sine wave signal SIE, the correction signal S5, and the correction signal S6 are inverted. As a result, signals of the following curves corresponding to all of the drift curves shown in FIGS. 3A to 3F are obtained.

5in(θ)...(5)sin
(θ) ... (6) s'n (θ + α) ... (7) s'n (θ + α)
...(8) sin(θ−α)
...(9) sin(θ−α)
...00) In this case, variable resistor V11+,
The amplitude of the curve and the like are precisely adjusted using Vj13, Vl14, VR5, and Vl16.

The signals output from these matrix circuits (18) are supplied to the drive circuit (20), which is connected to correction coils (34) and (35) for misland ink correction.
(36), (37), (38), and (39), respectively.

Next, referring to FIGS. 6 to 9, the correction coil (34)
(39) will be explained.

The correction coils (34) to (39) are flexible and are located at predetermined portions of the funnel portion (32) of the color polarization tube (30), that is, as shown in FIGS. 3A to F. pasted in position. This correction coil (34)
The ends of (39) are connected to terminals provided on the deflection yoke (14) with lead wires (34a), (35a), (
36a), (37a).

(38a) and (39a) are connected. Here, the correction coil (35) has an elliptical shape. As a result, the anode button (41) and the F4 wire portion of the correction coil (35) are prevented from being extremely close together or having a sharp point, thereby preventing leakage at high voltage.

FIG. 8 shows an enlarged view of the correction coil (34).

This correction coil (34) is made of, for example, a 70 μm thick sheet-like flexible member made of polyimide material, and has an outer diameter of 200 mm x 20 On+n+ and an inner diameter of 120 m.
For example, a 70 μm thick 'Af&' formed in advance on one surface of a sheet-like substrate (42) punched and cut into a ring shape of 120 mm x 120 mm is formed into a spiral shape by etching. This correction coil (34) is manufactured in the same manner as a well-known flexible circuit board. The coil (44) has an electrode take-out part (44a) and an electrode take-out part (44b) made of &P fB material.
is provided, and a spiral coil of, for example, 30 turns of residual copper foil is formed between them.

Furthermore, a cover coat part coated with a polyimide material is formed leaving the electrode extraction parts (44a) and (44b), thereby preventing oxidation and damage to the members of the coil (44). Furthermore, an adhesive is applied to the other surface of the sheet-like substrate (42), or an adhesive layer surface is formed using double-sided adhesive tape, and this adhesive layer surface is used to attach the funnel portion (32) of the color cathode ray tube (30). Can be attached directly to the glass surface of the

Incidentally, other correction coils (36) to (39) are manufactured in the same manner, and are attached to each part of the funnel part (32) of the color cathode ray tube (30) as shown in FIGS. 6 and 7. Can be pasted tightly.

Here, FIG. 9 shows other examples of the correction coils (34) to (39). This example is designed to make it easier to attach the correction coils (34) to (39) to the glass surface of the funnel section (32) of the color cathode ray tube (30). That is, the funnel part (32)
The glass part is curved, and when attaching the correction coils (34) to (39) to this curved glass part, the part where the sheet-like substrate (42) etc. are concentrated because it is not flat,
A so-called wrinkled portion is generated, but here, a protrusion (48) that becomes a wrinkled portion is provided in advance on the completed correction coils (34) to (39). For example, in the case of the correction coil (34), a protrusion (48) is provided at the lower left side, orthogonal to the sheet-like substrate (42).

This protruding portion (48) may be formed by press working or the like after completion of the correction coil (34) so as to match the shape of the glass portion to which the funnel portion (32) is attached. Note that the other configurations are similar to the above example.

Next, the operation in the above configuration will be explained.

The magnetic orientation sensor (10) is of the so-called Franks gate type and generates a sine wave signal S shown in FIG.

and cosine wave signal S2 can be obtained with relatively high sensitivity and accuracy. Then, a sine wave signal Sat and a cosine wave signal 52ff are output from the magnetic direction sensor signal processing unit (I2),
The sine wave signal SIE and cosine wave signal SEE are respectively input to a low pass filter (LPF) (14). Here, superimposed unnecessary waves, such as AC signals supplied to the drive coil, are removed, and adverse effects such as beat signals and the like with horizontal deflection frequency signals, etc. whose frequencies are similar, are prevented.

After this, a correction signal S is sent from the addition/subtraction circuit (16).

[, Convex +A”5in (θ + α)] and correction signal S6 [,
fT"T sin (θ - α)] is obtained. In this case, the value α is the phase difference with the Y-axis curve. Here, the smaller the deflection angle of the color cathode ray tube, the more The left and right drift curve becomes closer to the Y-axis curve. That is, the phase difference α becomes smaller.

Furthermore, the larger the deflection angle of the color cathode ray tube, the larger the phase difference α. Therefore, as the value of the cosine wave signal SEE adjusted (reduced) by the variable resistor Vll16 of the adder/subtractor circuit (16) changes, the phase difference α changes. When used, it becomes possible to cope with this by only adjusting the variable resistor VMI6. Here, in Fig. 10, the cosine wave signal S! The case where the adjusted value of E changes and the phase difference α is 45° and 26° is shown. As can be easily understood from the figure, the curves E and C at the upper left and upper right of the screen have a phase difference of 45° with respect to the drift curve A on the Y axis, and the drift curve A on the Y axis has a phase difference of 45°. Curves DXF at the upper left and upper right of the screen have a phase difference of 45° with respect to curve B. Note that in the case of a turnip where the phase difference α at the bottom of the Y axis, the bottom left of the screen, and the bottom right of the screen is 45° and 26°, respectively, the phase difference is only reversed.

The correction signals S and S6 thus generated are connected to the correction coil (3) together with the sine wave signal SIE via the matrix circuit (18) to the drive circuit (20).
4) to (39), respectively. This correction coil (
34) to (39) are flexible and are provided with protrusions (48) in advance. As a result, the correction coil (3) is placed on the curved surface of the glass part of the funnel part (32).
4) to (39) are absorbed when they are pasted in close contact, so that, for example, manual pasting becomes easier and the workability is improved.

Furthermore, the coils (4) of the correction coils (34) to (39)
4) is a copper foil member that occupies a relatively large area and is attached to the funnel part (32), which eliminates the need for conventional magnetic shielding and also allows accurate correction of the trajectory that displaces the electron beam. This compensates for the deterioration in color utility.

In this way, geomagnetic correction data is calculated from the value of the detected geomagnetic field, and a correction current is applied based on this calculated value to generate a correction magnetic field. Misland ink can be corrected continuously. In addition, by simply adjusting and setting the variable resistor Vl16 of the adder/subtractor circuit (16), a single type of circuit board can be used to correct misland ink in various color cathode ray tubes, improving its versatility. .

It is clear that the present invention is not limited to the above-described embodiments, and that various changes can be made without departing from the gist of the present invention.

〔Effect of the invention〕

As can be understood from the above description, the magnetic field correction device for color cathode ray tubes of the present invention calculates geomagnetic correction data from the value of the detected geomagnetic field, and corrects it by flowing a correction current based on the calculated value. Since a magnetic field is generated, there is an advantage that the activation of the electron beam can be continuously corrected in accordance with the detected magnetic field strength and in accordance with the direction. This has the advantage of being able to handle beam activation correction and improving its versatility.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing an embodiment of the magnetic field correction device for a color cathode ray tube according to the present invention, Fig. 2 is a waveform diagram of the output signal of the magnetic direction sensor, and Fig. 3 is a diagram showing the waveform of the output signal of the magnetic direction sensor. Figure 4 is a block diagram showing the configuration of the adder/subtracter circuit; Figure 5 is a detailed circuit diagram of the adder circuit that constitutes the adder/subtracter circuit shown in Figure 4; Figure 6 is a diagram showing the configuration of the adder/subtractor circuit shown in Figure 4. FIG. 7 is a rear view showing the state in which the correction coil is installed; FIG. 7 is a side view showing the state in which the correction coil is installed for a color cathode ray tube; FIG. 8 is a plan view showing the detailed configuration of the correction coil; FIG. 6 is a plan view showing another embodiment of the correction coil shown in FIG. 6, and FIG. 10 is a characteristic diagram of a correction signal used to explain the operation of FIG. 1. (10) is a magnetic direction sensor, (12) is a magnetic direction sensor signal processing section, (14) is a low pass filter, (16)
) is an addition/subtraction circuit, (16a) is an addition circuit, (16b) is a subtraction circuit, (18) is a matrix circuit, (20) is a drive circuit, (30) is a color cathode ray tube, (34) (
35) (36) (37) (38) (39) are correction coils, Sl is a sine wave signal, S2 is a cosine wave signal, S, S
6 is a correction signal, and vtub is a variable resistor. Agent Hidemori Matsukuma 05 voice N, 71 of the calculation role. The 4th image of the power DJ [mouth's bathing, the 5th figure, 6th figure, the CTR, the 4th figure of Nishiki Nao, the 4th figure of Inuzu figure 7, the 4L illusion of the Minamimasa Phil, the 4th figure of the 8th figure. The full text of the detailed statement of procedural amendments for Figure 9 of JJ Shōhachi for Yamanomi ga 1 of Minamisho Coil is corrected as shown in the attached sheet. street

Claims (1)

[Scope of Claim] A magnetic field correction device for a color cathode ray tube that corrects misland ink in a color cathode ray tube equipped with a color selection mask, comprising: a magnetic sensor, a calculation section, a drive circuit, and a correction coil; A collar characterized in that the magnetic sensor detects earth's magnetism, the calculation section calculates earth's magnetic correction data, supplies it to the drive circuit, and causes a correction current to flow through the correction coil to generate a correction magnetic field. Magnetic field correction device for cathode ray tubes.