JPH04360389A - Television receiver - Google Patents

Abstract

PURPOSE:To eliminate the need for a troublesome job by deciding an earth magnetism correction quantity to minimize a magnetic field detected by a magnetic field sensor and implementing external magnetic field correction in response to the correction quantity when a television receiver is set. CONSTITUTION:A magnetic field in a television receiver is detected by a magnetic field sensor 21 and a correction quantity control section 22 controls a correction quantity in response to the magnetic field and when a current is supplied to an earth magnetism correction coil 24 via a coil drive section 23, a magnetic field in the television receiver is changed and controlled. Furthermore, the magnetic field in this state is again detected to control the correction quantity and the magnetic field is changed and controlled, the processing above is repeated to converge the effect of the external magnetic field so as to be minimized, the earth magnetism correction quantity is decided and stored in a correction quantity storage memory 25. When the television receiver is turned on, the correction quantity in the correction quantity storage memory 25 is read and a current is supplied to the earth magnetism correction coil 24 via a coil drive section 23 to correct the earth magnetism.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a television receiver having a function of correcting external magnetic fields such as terrestrial magnetism that adversely affect the television receiver.

0002

BACKGROUND OF THE INVENTION In recent years, there has been an increasing demand for television receivers to produce large-screen images that provide even more impact and realism, as well as higher-quality images. Therefore, in a direct-view color television receiver using a cathode ray tube (hereinafter referred to as CRT), the beam landing condition changes depending on the direction the television receiver is facing due to the influence of horizontal geomagnetism. This effect becomes a problem as it becomes a John receiver. For example, red in a color television receiver,
In the green and blue (hereinafter referred to as R, G, and B) coloring process, after the electron beam passes through the shadow mask, it may not land correctly on each phosphor, or it may land on a phosphor of a different color. I put it away. In order to suppress the influence of the earth's magnetic field, there are methods such as applying shield plates to the back and sides of the CRT, and installing a coil that generates a magnetic field to cancel the earth's magnetic field on the inside and outer circumference of the television receiver, and passing current through the coil. There is a method to correct the geomagnetism.

[0003] A conventional geomagnetic correction method will be explained below with reference to the drawings. As shown in FIG. 3, its components include a television receiver 31 and a CRT
33 is a geomagnetic vector, 34 is a coil for geomagnetic correction, and 35 is the direction of the generated magnetic field. As shown in FIG. 3A, the earth's magnetism relative to the television receiver 31 is divided into three orthogonal components: a vertical direction, a horizontal direction parallel to the CRT surface 32, and a horizontal direction perpendicular to the CRT surface 32. Figure 3(b) shows how to cancel the vertical geomagnetic component.
As shown in FIG. 3(c), to cancel the horizontal geomagnetic component parallel to the CRT surface 32, as shown in FIG. 3(c), to cancel the horizontal geomagnetic component perpendicular to the CRT surface 32, as shown in FIG.
As shown in (d), coils 34 are arranged in each case to flow current to correct the geomagnetism.

[0004] However, since television receivers are generally manufactured for limited use areas on the earth, the vertical geomagnetism can be adjusted by setting the geomagnetic field in advance to suit the area of use. In this range, the coil 34 shown in FIG. 3(b) becomes unnecessary. Also, C
In response to changes in the geomagnetic field in the horizontal direction parallel to the RT plane 32, the electron beam fluctuates almost vertically, but R, G, B
In the case of a CRT having a stripe structure in which each phosphor is arranged in one vertical column, the coil 34 shown in FIG. 3(c) is not provided because the influence on beam landing is small. Furthermore, in the direction of omitting the coil, the coil 34 for correcting the geomagnetism in the horizontal direction perpendicular to the CRT surface 32 shown in FIG. 3(d) is often arranged only on the outer periphery of the CRT surface 32. If the earth's magnetism is corrected by appropriately applying current to the coils 34 arranged in this manner, it is possible to suppress changes in the beam landing state depending on the direction in which the television receiver 31 faces.

FIG. 4 shows a schematic configuration of a geomagnetic correction circuit for a conventional television receiver. As shown in FIG. 4, its components include a direction/correction amount setting section 41, a coil drive section 42, a geomagnetic correction coil 43, and a direction 44 for feedback by visual inspection of the screen.

[0006] A user or a service person determines the direction in which the installed television receiver faces, and selects and inputs the direction into the direction/correction amount setting section 41 using an operation panel or a remote control. According to the direction, current is applied to the geomagnetic correction coil 43 via the coil drive unit 42 with a preset correction amount to perform geomagnetic correction. Alternatively, while checking the beam landing state by directly viewing the screen or viewing it under a microscope, the direction/correction amount setting unit 41 directly adjusts the current flowing through the geomagnetic correction coil 43 using the feedback direction 44 to perform geomagnetic correction. Is going.

[0007]

However, in the above-mentioned conventional television receiver, the horizontal geomagnetic field relative to the television receiver changes each time the direction in which the television receiver is installed changes. Determine the direction and enter the selection, or
Manual adjustments must be made by visually checking the screen, etc.
This has the problem of requiring very troublesome work.

The present invention solves the above-mentioned conventional problems, and even if the direction in which the television receiver is installed is changed, the user does not have to judge the direction or make manual adjustments by visual inspection. The object is to provide a television receiver that does not require troublesome operations.

[0009]

[Means for Solving the Problems] In order to achieve the above object, the television receiver of the present invention includes a coil that generates a magnetic field inside the television receiver, and a sensor that is provided near the coil and detects the magnetic field. and a control unit that controls the amount of correction according to the magnetic field detected by the sensor, and a drive unit that causes current to flow through the coil according to the amount of correction.
When the television receiver is in a standby state (this is a standby state in which power is turned on only to parts that require preheating, such as the CRT heater, hereinafter referred to as the standby state), the sensor The storage section stores a correction amount determined by repeatedly operating the control section and the driving section so that the detected magnetic field becomes the minimum value.

0010

[Operation] The television receiver configured as described above detects the influence of the magnetic field inside the television receiver using a sensor when the television receiver is in standby mode, that is, when only necessary parts such as the CRT heater are being driven. The external magnetic field is canceled out by measuring the magnetic field in the area that is easily affected by the magnetic field, and by controlling the control unit and the driving unit to flow current through the coil so as to minimize the measured magnetic field. Since the magnetic field is measured when the television receiver is in standby mode, it is not affected by the magnetic field generated by the television receiver itself (for example, the magnetic field caused by the deflection yoke) and has the feature of being able to accurately correct the external magnetic field. It is. Therefore, even if the direction in which the television receiver is installed is changed, the user or service person has to judge the direction and enter the selection, or make manual adjustments by visually checking the screen, which is a cumbersome task. Appropriate external magnetic field correction, such as terrestrial magnetism, can be performed simply by executing the above operation while the television receiver is in standby mode.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the television receiver of the present invention will be described below with reference to the drawings. FIG. 1 shows a television receiver equipped with a coil for correcting horizontal terrestrial magnetism. As shown in FIG. 1, its components include a television receiver 11, a CRT screen 12,
13 is a geomagnetic correction coil. FIG. 2 is a block diagram of a portion of the television receiver according to this embodiment relating to geomagnetic correction. As shown in FIG. 2, its components include a magnetic field sensor 21, a correction amount control section 22, a coil drive section 23, and a coil drive section 23.
4 is a geomagnetic correction coil, 25 is a correction amount storage memory as a storage section, and 26 is a feedback path based on magnetic field detection.

[0012] The operation related to geomagnetic correction of the television receiver configured as above will be explained. If you change the direction or location in which the television receiver is installed, the horizontal geomagnetic field relative to the television receiver will change and affect beam landing, so users should change the direction or location in which the television receiver is installed. This fact is input using an operation panel or remote control (not shown). Thereby, in order to determine an appropriate amount of geomagnetic correction, when the television receiver is in standby, the magnetic field sensor 21 first detects the magnetic field inside the television receiver, and then the amount of correction is determined according to the detected magnetic field. Control unit 22
The magnetic field inside the television receiver is changed and controlled by controlling the amount of correction by controlling the amount of correction, and by passing current through the geomagnetic correction coil 24 via the coil drive unit 23 according to the amount of correction. Furthermore, the magnetic field in this state is detected again, the correction amount is controlled, and the operation of changing and controlling the magnetic field is repeated until it converges to minimize the influence of the external magnetic field, determining the appropriate geomagnetic correction amount, and then making corrections. The amount is stored in the amount storage memory 25. When the television receiver is in the on state, the correction amount stored in the correction amount storage memory 25 is read out, and current is passed through the geomagnetic correction coil 24 via the coil drive unit 23 according to the correction amount, thereby adjusting the geomagnetic field. Corrections can be made. In this way, by canceling out the influence of external magnetic fields such as the earth's magnetism with the magnetic field produced by the magnetic correction coil, the television receiver can receive images in the best condition when the power is turned on, even if the position or direction of the receiver changes.

[0013]

As is clear from the above description, the television receiver of the present invention includes a coil that generates a magnetic field inside the television receiver, a sensor that detects the magnetic field provided near the coil, and a sensor that detects the magnetic field. It has a control section that controls the amount of correction according to the detected magnetic field, a drive section that sends current to the coil according to the amount of correction, and a storage section that stores the amount of correction. The control unit and the drive unit are repeatedly operated to determine the correction amount so that the magnetic field detected by the sensor becomes the minimum value when the television receiver is in the on state, and the amount of correction is stored in the memory unit. Due to the configuration in which current is passed through the coil according to the amount of correction, images can be received in the best condition even if the direction in which the television receiver is installed is changed. In addition, users and service personnel do not have to perform troublesome tasks such as determining the direction and inputting a selection, or manually adjusting the direction by visually checking the screen, etc., and when the television receiver is in standby, the Appropriate correction of external magnetic fields such as earth's magnetism can be performed simply by executing the operation.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the concept of arranging coils for geomagnetic correction in a television receiver according to an embodiment of the present invention.

FIG. 2 is a block diagram showing the configuration of a portion related to geomagnetic correction in a television receiver according to an embodiment of the present invention.

[Figure 3] (
(a) is an external perspective view showing the direction of the earth's magnetic field and an external perspective view of the television receiver (b) is an external perspective view showing the position of the coil for correcting the earth's magnetic field in the television receiver with respect to the vertical earth's magnetic field (c) is a horizontal view parallel to the CRT surface (d) is an external perspective view showing the position of the geomagnetic correction coil of the television receiver with respect to the geomagnetism in the horizontal direction perpendicular to the CRT surface.

[Figure 4] Block diagram showing the configuration of a conventional television receiver related to geomagnetic correction

[Explanation of symbols]

21 Magnetic field sensor 22 Correction amount control section 23 Coil drive section 24 Geomagnetic correction coil 25 Correction amount memory

Claims (1)

[Claims] 1. A coil that generates a magnetic field inside a television receiver, a sensor that detects the magnetic field provided near the coil, and a control unit that controls a correction amount according to the magnetic field detected by the sensor. , comprising a drive unit that causes a current to flow through the coil according to the correction amount, and a storage unit that stores the correction amount, and the magnetic field detected by the sensor when the television receiver is in a standby state has a minimum value. In the television receiver, the storage section stores the correction amount determined by repeatedly operating the control section and the drive section.