GB2364574A

GB2364574A - System for automatically emulating different directional earth magnetic fields

Info

Publication number: GB2364574A
Application number: GB0123890A
Authority: GB
Inventors: Se Hoon Oh
Original assignee: LG Electronics Inc
Current assignee: LG Electronics Inc
Priority date: 1999-03-18
Filing date: 2000-03-13
Publication date: 2002-01-30
Anticipated expiration: 2020-03-13
Also published as: GB0123890D0; GB2364574B; GB2364574A8

Abstract

A magnetic field control apparatus comprises input means 30 for selecting a desired magnetic field and a control system 20 for controlling the power supplied to a coil to automatically provide the desired magnetic field within a chamber 50. The control system may include a memory storing earth magnetic field values and corresponding power supply adjustment data. A gauss meter 11 may be used to automatically attain the magnetic field target value. Also disclosed is a method suitable for obtaining a desired magnetic field comprising the input of a desired earth magnetic value, reading corresponding earth magnetic field data stored in a memory and automatically adjusting a power supply according to the said data to obtain the desired earth magnetic field. Further disclosed is a method comprising keying in a desired earth magnetic value, displaying a menu, selecting a memory address and adjusting a power supply according to the power adjusting data which corresponds to the said memory address or generating an error signal if there is insufficient data.

Description

2364574 APPARATUS FOR AUTOMATICALLY CONTROLLING DIRECTIONAL

EARTH MAGNETIC FIELD AND METHOD THEREOF

The present invention relates to a technique for controlling an earth 5 magnetic field that has a close relation to picture quality, and more particularly, to an apparatus and a method for automatically controlling a directional earth magnetic field which is capable of automatically setting and modifying the strength and direction of the earth magnetic field.

In particular, earth magnetic field values are stored in a memory unit of a

10 system controller by using an automatic memory function so that when an earth magnetic field value to, be set as desired by an operator is inputted, earth magnetic field data corresponding to the earth magnetic field value inputted from the earth magnetic field data stored in the memory unit is read. Using this data, an output voltage of a power supply unit of an earth magnetic field

15 chamber is variably adjusted so that a desired earth magnetic field value is automatically set or modified.

Figure I is a schematic block diagram of an apparatus for controlling an earth magnetic field in accordance with conventional art, which includes a gauss meter I I installed in an earth magnetic field chamber, and power supply

20 units 10A, 10B and 10C connected to the gauss meter 11 for respectively supplying a power of three axes X, Y and Z.

In the conventional earth magnetic field, the operator identifies a numerical value of the gauss meter 11 and manually adjusts a voltage value of the power supply units 10A, 10B and IOC to set a desired earth magnetic field

25 value.

However, since the strength and the direction of the earth magnetic field values are different in every region of the world, the earth magnetic field values need to be set differently when a monitor is being manufactured depending on the regions where the monitor is to be sold. Thus, in such a conventional system, the operator has to set an earth magnetic field value by manually adjusting a voltage value of the power supply units 10A, IOB and IOC while 5 looking up a gauss meter. A problem with this is that it takes a long time to set and modify the earth magnetic field value, and thus, productivity is lowered.

An object of the present invention is to provide an apparatus for automatically controlling a directional earth magnetic field. This apparatus includes a system controller to which a gauss meter is connected through a 10 communication interface. Each earth magnetic field value measured by the gauss meter is transferred from the system controller through the interface and stored in a memory unit of the system controller, thereby providing an automatic memory function, and, when an earth magnetic field value desired to be set by a user is inputted through a key input, the system controller reads earth 15 magnetic field data corresponding to the earth magnetic field value inputted from the earth magnetic field data stored in the memory unit, and an output voltage of a power supply unit is adjusted by using the earth magnetic field data corresponding to the earth magnetic field value inputted from the earth magnetic field data stored in the memory unit, and an output voltage of a power

20 supply unit is adjusted by using the earth magnetic field data, thereby automatically setting the earth magnetic field value of an earth magnetic chamber.

Various aspects of the invention are defined in the independent claims.

Some preferred features are defined in the dependent claims.

25 As previously mentioned, the earth magnetic field value effects the picture quality of a monitor and is different in strength and direction in every region of the world. Thus, a suitable earth magnetic field value has to be set for each region in order to adjust the screen of the monitor, when the monitor is fabricated.

Accordingly, an automatic memory function is provided for automatically setting the strength and the direction of the magnetic field

5 generated by an earth magnetic field chamber.

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

10 In the drawings:

Figure I is a schematic block diagram of an apparatus for controlling an earth magnetic field in accordance with conventional art;

Figure 2 is a schematic view of an apparatus for controlling a directional earth magnetic field in which the present invention is embodied;

15 Figure 3 is a flow chart of an automatic memory process of Figure 2 in which the present invention is embodied; Figure 4 is a flow chart of a process of automatically controlling a directional earth magnetic field using the apparatus of Figure 2;

Figure 5 shows a displayed menu of Figure 4; 20 Figure 6 is a flow chart of a process of performing a memory process at three axes of X, Y and Z of Figure 3.

Figures 7A and 7B show tables of automatic memory data.

Figure 2 is a schematic view of an apparatus for controlling a magnetic field. This has a power supply unit 10 which applies a voltage to a coil of an

25 earth magnetic field chamber 50, which is operable to generate an earth magnetic field. Provided in the chamber 50 is a three axis gauss meter 11,

which is connected through a communication interface 12 to a system controller 20. Earth magnetic values measured by the gauss meter 11 are stored in the internal memory of the system controller 20, which is operable to variably control a voltage applied to the coil of the earth magnetic field chamber 50 from the power supply unit 10 to thereby automatically set an earth magnetic field

5 value.

The key input 30 inputs an input information or a command of a user such as selection of an address and a direction of the earth magnetic field to the system controller 20.

The screen display unit 40 displays an earth magnetic field value set by

10 the system controller 20.

Figure 3 is a flow chart of an automatic memory process.

First, X, Y, Z regions are set in the earth magnetic field chamber 50 and the three axes gauss meter 11 is positioned at a predetermined space at which the earth's magnetic field is to be measured, see step S1. Then, the system

15 controller 20 judges whether there is a memory scanning or not in step S2.

Upon such judgement, if there is no memory scanning, the system controller is taken out of the process loop, while, if there is a memory scanning, the system controller 20 memorizes values of X, Y, 0 in the memory in step S4, and then memorizes values of 0, Y, Z in step S5. Thereafter, the,system controller 20 20 updates the memory in step S6.

In the above processes, as the system controller 20 is connected to the gauss meter 11 by the communication interface 12, when the automatic memory function is performed, the system controller,20 receives the earth magnetic field value measured by the gauss meter I I through the communication interface and 25 stores it in its internal memory unit, so that the earth magnetic field value is read by 0. 1 G unit for each axis of the earth magnetic field chamber in the range of -0.6-+0.6G and memory tables of (X,Y,O) and (0,Y,Z) are formed.

The reason for forming two memory tables of (X,Y,O) and (0,Y,Z) when setting the automatic memory function is that if the memory is made by 13 steps on the three axes of (X,Y,Z), 2197 pairs of memory tables are made, which disadvantageously causes the time taken for setting the automatic memory to be 5 too long. Therefore, on the basis that the Z (horizontal direction) earth magnetic field is always '0' and by forming the two memory tables (X,Y,O) and (0,Y,Z) that respectively take X (vertical direction) earth magnetic field and Z (horizontal direction) earth magnetic field for changing the earth magnetic field, the direction of the earth magnetic field is changeable by referring to a

10 corresponding memory table every time when the direction of the earth magnetic field is rotated by 90', and at the same time, the time taken for automatic memory is reduced. Thereafter, the system controller 20 stores the earth magnetic field value as transferred by giving an address to the two memory tables.

15 Figure 4 is a flow chart of a process of automatically controlling a directional earth magnetic field by using the automatic memory function of

Figure 2. First, an earth magnetic field value desired to be set by the operator is inputted through key operation of the key input unit 30 in step S1. Then, a menu for selecting an earth magnetic field data is displayed on the screen

20 display unit 40 in step S2. The system controller 20 of Figure 2 judges that an address is selected in step S3. If the address was not selected in step S3, the system controller 20 judges again whether a basic earth magnetic field value was outputted in step S4. If the basic earth magnetic field value was not outputted, an error signal sound is generated and an error is displayed in step 25 S8. In the step S3, if the address was selected, an address memory is checked to determine whether there is an earth magnetic field value corresponding tot he address in step S5.

Upon checking the address memory in step S5, if there is no corresponding earth magnetic field value data, step S8 is performed, while if there is a corresponding earth magnetic field value data, the data memory is re checked to discern whether there is power supply adjusting data in the power 5 supply unit 10 in step S6. If there is no power supply adjusting data in step S6, step S8 is performed, while if there is power supply adjusting data, a corresponding power supply adjusting data of the memory table is read in step S7, and an output value of the power supply unit 10 is converted in step S9.

Figure 5 shows a displayed menu of Figure 4.

10 'Auto Memory (AUTO MEM)' is one for the earth magnetic field automatic memory processing shown in Figure 3 according to the selection of the operator. 'Address Memory (ADD WM)' is one for inputting the earth magnetic field value desired to be displayed by the operator on the axes of (X,Y,Z). 'INT/EXT' is one for determining whether the system is operated by 15 INT(Key board) or by EXT(Key box). 'SELF TEST' is for self-testing a hardware part of the system. 'Address(ADD)' is for selecting the address in step S3.

Figure 6 is a flow chart of a process of performing a memory at three axes of X, Y and Z of Figure 3. First, values of Xl, Yl and Z1, that is, target 20 values of the three axes earth magnetic field, are set in step S 1. The target value

X1 is compared to a gauss value x outputted from the X axis of the current power supply unit in step S2. If the value x is greater than the value X1, the value is reduced in step S3, while if the value x is smaller than the value X1, the x value is increased in step S4. If the value x is the same as the value X1, the 25 process goes to the next step.

Likewise, the target value Y I is compared with a gauss value y outputted from the Y axis of the current power supply unit in step S5. If the value y is greater than the value Yl, the value y is reduced in step S6, while, if the value y is smaller than the value Yl, the value y is increased in step S7. If the value y is the same as the value Yl, the process goes to the next step.

In the same manner, the target value Z I is compared with a gauss value z 5 outputted from the Z axis of the current power supply unit in step S8. If the value z is greater than the value Z1, the value z is reduced in step S9, while, if the value z is smaller than the value Z1, the value z is increased in step SIO. If the value z is the same as the value Z1, the process goes to the next step S2.

Figure 7A shows voltage and current output values of the power supply 10 units of each axis after automatically memorizing each earth magnetic field value of X and Y axes by taking Z axis to be '0', and Figure 7B shows voltage and current output values of the power supply units of each axis after automatically memorizing each earth magnetic field value of Y and Z axes by taking the X axis to be '0'. In this respect, the range of the earth magnetic field

15 value of each axis is -0.6-0.6G, and the maximum voltage value of the power supply unit is 50V and the maximum current value is 5A.

For a detailed explanation, the operator may input an earth magnetic field value desired to be set by operating the key of the key input unit 30, or may select an address of a desired earth magnetic field data from the menu displayed

20 on the screen. When the system controller 20 reads the earth magnetic field value data corresponding to the selected address, the output voltage of the power supply unit 10 is controlled by using the earth magnetic field data.

Under the control of the system controller 20, the power supply unit 10 applies a voltage of a predetermined level to the coil of the earth magnetic field

25 chamber, so that the earth magnetic field value desired by the operator is automatically set.

Here, the operator simply operates an UP/DOWN key or a SHIFT key provided in the key input unit 30, so that he or she adjusts the earth magnetic field value or the direction of the earth magnetic field displayed on the screen display unit 40 in every direction minutely to thereby easily consider how the earth magnetic field value and the direction change of the earth magnetic field

5 affect the picture quality of the monitor.

At the same time, the screen display unit 40 displays the earth magnetic field value as set under the control of the system controller on the screen.

The screen display unit 40 is made of a bifacial panel to display the set earth magnetic field value on both sides thereof, so that the operator part can

10 easily identify whether the earth magnetic field value was changed, and thus, an inadvertent modification of the earth magnetic field value due to the operator can be prevented.

Meanwhile, in a state that a menu for selecting an earth magnetic field data is displayed on the screen display unit 40, in case that an address of the 15 earth magnetic field value desired to be set by the user is not inputted or if the earth magnetic field data selected by the user does not exist, the system controller 20 generates a warning sound and displays an error message on the screen display unit 40. At this time, the user sets an earth magnetic field value and an earth magnetic field direction by operating the key.

20 That is, when the user inputs an earth magnetic field value desired to be set by key inputting, the system controller 20 reads an earth magnetic field data corresponding to the inputted earth magnetic field value from the memory unit and controls a voltage outputted from the power supply unit 10 by using the earth magnetic field data, thereby setting an earth magnetic field value as

25 desired by the user.

As so far described, in the apparatus and method for automatically controlling directional earth magnetic field of the present invention, after earth magnetic field values are stored in the memory unit of a system controller by using the automatic memory function, when the earth magnetic field value to be set as desired by an operator is inputted, the earth magnetic field data corresponding to the earth magnetic field value inputted from the earth

5 magnetic field data stored in the memory unit is read, and by using this data, the stored output voltage of the power supply unit is read and by using this data, the output voltage of the power supply unit of the earth magnetic field chamber is adjusted so as to be automatically set or modified to the desired earth magnetic field value.

Claims

CLAIMS:

1. A method for automatically controlling directional earth magnetic field, comprising the steps of:

generating an earth magnetic field by supplying power to a coil of the 5 earth magnetic field chamber; positioning a gauss meter at the place where an earth magnetic field is desired to be measured, receiving the earth magnetic field value measured by the gauss meter through a communication interface; 10 storing data indicative of the earth magnetic field value in a memory, reading the stored earth magnetic field data when an operator inputs an earth magnetic value desired to be set; and variably controlling an output voltage of a power supply using the earth magnetic field data as read to automatically set a desired earth magnetic field 15 value.

2. A method as claimed in claim 1, further comprising giving an address to each earth magnetic field value.

20

3. A method as claimed in claims I or claim 2, further comprising the steps of setting a target value for the earth magnetic field; comparing the current earth magnetic field value outputted from the power supply unit and the target value, and increasing or decreasing the current 25 earth magnetic field value accordingly until the target value is reached.

4. A method as claimed in claim 3, wherein the step of setting comprises setting a target value for the earth magnetic field of the three axes of X, Y and Z, and the step of comparing comprises:

comparing the current earth magnetic field value outputted from the power supply unit on the X axis and the target value of the X axis, and 5 increasing or decreasing the current earth magnetic field value on the X axis; comparing the current earth magnetic field value outputted from the power supply unit on the Y axis and the target value of the Y axis, and increasing or decreasing the current earth magnetic field value on the Y axis; and 10 comparing the current earth magnetic field value outputted from the power supply unit on the Z axis and the target value of the Z axis, and increasing or decreasing the current earth magnetic field value on the Z axis.