KR19980035722A - Tilt Correction Circuit of Monitor - Google Patents

Abstract

The present invention relates to a tilt correction circuit of a monitor, the device of the present invention is wound around the CRT net portion, the tilt correction coil 10 for generating a magnetic field according to the magnitude of the current flowing to correct the tilt of the screen; A key input unit 20 through which a user inputs an up / down key to correct the tilt; A microcomputer 30 for outputting a correction signal whose level is variable according to the key input; And a voltage connected between both ends of the tilt correction coil 10 to adjust a direction and magnitude of a current flowing through the tilt correction coil 10 by changing a voltage between both ends of the tilt correction coil 10 according to the correction signal. It is composed of a current adjusting unit 40, by changing the direction of the deflection current, the screen tilt phenomenon caused during the manufacturing process or under the influence of the geomagnetic field can be easily corrected according to the present invention, the effect is Big.

Description

A circuit for compensating tilt in a monitor

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tilt correction circuit of a monitor adapted to correct an inclination of a screen generated by a CRT or during a geomagnetic field.

In general, Cathode Ray Tube (CRT) focuses and accelerates hot electrons emitted from R, G and B electron guns, and then collides with R, G and B fluorescent surfaces through a point on a shadow mask to form pixels, and vertical and horizontal deflection coils. Sawtooth current flows to form a two-dimensional screen.

Since the CRT requires very precise operation to form high density pixels on a narrow screen, various correction devices, for example, a push magnet and a convergence magnet, are mounted on the neck of the CRT. In order to prevent deterioration of the image quality, an element coil is provided in the panel portion of the CRT.

FIG. 1 is a diagram illustrating a structure of a general CRT. As shown in FIG. 1, the CRT includes a base 1, an electron gun 2, a net 3, a cone 4, a panel 5, and a fluorescent plate ( 7) and the shadow mask 8 or the like.

Here, the base 1 is for connecting an electrical signal to the CRT, and the net 3 has an electron gun 2 for forming R, G, and B electron beams, which are emitted from this electron gun and focused and accelerated. It concentrates on this shadow mask 8 and impinges on the fluorescent surface 7.

When the display surface and the shadow mask 8 do not coincide with each other in the manufacturing process of such a general CRT, the screen is slightly tilted.

Also, the display is slightly inclined due to the influence of the geomagnetic field. As is well known, the earth forms a geomagnetic field with a huge magnet, which is a display operated by an electric magnetic field such as a CRT. It affects the device, and since this geomagnetic field is different depending on the position on earth, it is difficult to uniformly correct it.

The phenomenon that the screen is tilted due to such various causes is called tilt, and a tilt correction coil L as shown in FIG. 2 is generally used to correct this electromagnetically.

That is, in the conventional tilt correction circuit, as shown in FIG. 2, after winding the tilt correction coil L around the CRT net 3, the base ends of the two pairs of push-pull amplifiers Q1, Q2, Q3 and Q4. By adjusting the voltage, the current flowing through the tilt correction coil L is adjusted, thereby rotating the tilted screen as a whole to correct the tilt.

That is, when the MICOM outputs a tilt correction signal to control the magnitude of the correction current by the user's up / down key input, the differential amplifier OP1 compares the correction voltage with the reference voltage by the difference. Output amplified.

The signal output from the differential amplifier OP1 is buffered in the buffer OP2 and then applied to the base end of the push-pull amplifiers Q1 and Q2.

At this time, if the input side (A) voltage of the push-pull amplifiers (Q1, Q2) is greater than the output side (B) voltage, the transistors (Q1, Q4) is turned on, so that the power supply voltage (Vcc1) is the transistor ( It is applied to the collector stage of Q1) and output through the emitter stage and applied to the tilt correction coil L via the resistor R9 and the capacitor C1. Accordingly, the current in the tilt correction coil (L1) This occurs and is bypassed to ground through the emitter and collector stages of the transistor Q4.

On the contrary, when the voltage of the input side A of the push-pull amplifiers Q1 and Q2 is smaller than the voltage of the output side B, the transistors Q2 and Q3 are turned on, so that the power supply voltage Vcc2 becomes the transistor Q3. Is applied to the collector stage of the < RTI ID = 0.0 >)< / RTI > Accordingly, the current in the tilt correction coil (L1) This occurs and is bypassed to ground through the emitter and collector stages of the transistor Q2.

As a result, the direction and magnitude of the correction current applied to the tilt correction coil L are determined according to the A point voltage, that is, the base voltage applied to the push-pull amplifiers Q1 and Q2, and thus the direction and magnitude of the overall deflection current. Correct the tilt by changing.

However, the conventional tilt correction circuit has a problem in that the component is complicated as described above and requires a large amount of space for arranging the element in a limited space such as a PCB substrate of a monitor.

Accordingly, an object of the present invention is to provide a tilt correction circuit of a monitor that has a simple circuit configuration and corrects an inclination of a screen.

The tilt correction circuit of the monitor according to the present invention for achieving the above object, the tilt correction coil wound around the CRT net, generating a magnetic field according to the magnitude of the current flowing to correct the tilt of the screen; A key input unit for inputting an up / down key for the user to correct the tilt; A microcomputer for outputting a correction signal whose level is variable according to the key input; It is connected between both ends of the tilt correction coil, characterized in that it comprises a current control unit for controlling the direction and magnitude of the current flowing through the tilt correction coil by changing the voltage across the tilt correction coil in accordance with the correction signal do.

That is, when the microcomputer outputs the correction signal by the user's up / down key input, the current controller changes the voltage between both ends of the tilt correction coil according to the correction signal to change the direction and magnitude of the current flowing through the tilt correction coil. By doing so, the direction of the deflection current is changed.

1 is a diagram illustrating a structure of a general CRT;

2 is a circuit diagram showing a tilt correction circuit of a general monitor;

3 is a circuit diagram showing a tilt correction circuit of the monitor according to the present invention.

* Names of symbols for main parts of the drawings

10: tilt correction coil (L) 20: key input unit

30: micom 40: current supply unit

41: differential amplifier (OP1) 42: buffer (OP2)

43: clamping portion (D1, D2) R1 to R5: resistance

R6, C1: delay unit

Hereinafter, an embodiment according to the present invention will be described with reference to the accompanying drawings.

3 is a circuit diagram illustrating a tilt correction circuit according to the present invention.

As shown in FIG. 3, the apparatus of the present invention includes a tilt correction coil 10, a key input unit 20, a microcomputer 30, and a current control unit 40.

Here, the current controller 40 includes a differential amplifier 41 for receiving a correction voltage output from the microcomputer 30 and comparing the voltage with a reference voltage to amplify the difference; After receiving and buffering the output signal of the differential amplifier 41, it is supplied to one end of the tilt correction coil 10, and the feedback input signal output from the other end of the tilt correction coil 10, input side The buffer 42 is configured to supply a current to the tilt correction coil by the voltage difference between (A) and the output side (B).

Next, the operation and effects of the present invention configured as described above will be described in detail.

The key input unit 20 is a part in which a user inputs a key to correct the tilt, and includes an up / down key for controlling the magnitude of the correction current.

According to a user's up / down key input, the microcomputer 30 outputs a tilt correction signal to control the magnitude of the correction current. At this time, the correction signal is provided from the microcomputer 30, for example, a variable direct current (DC) voltage between 0 and 5V.

The differential amplifier 41 receives a correction signal between 0 and 5 V from the microcomputer 30, compares it with a reference voltage, amplifies the difference, and outputs the difference to the buffer unit 42.

Accordingly, the current flowing through the tilt correction coil 10 is adjusted by the voltage difference between the input side A and the output side B of the buffer unit 41.

That is, the maintenance signal output from the microcomputer 30 is input to the negative input terminal of the first OP amplifier OP1 by adjusting the current and voltage by the resistor R1, and the reference voltage (+) to the positive input terminal. ) Is entered.

Accordingly, the reference voltage input to the (+) input terminal of the first OP amplifier OP1 ) And the voltage input to the (-) input terminal is compared to determine the output voltage of the first OP amplifier OP1.

Since the output voltage of the first OP amplifier OP1 is input to the negative input terminal of the second OP amplifier OP1 through the resistor R3, the output voltage of the first OP amplifier OP1 is the resistor R5, Is applied to the tilt correction coil 10 via R6) and capacitor C1.

At this time, since the other end of the tilt correction coil 10 is fed back to the negative input terminal of the second OP amplifier OP2, the input side (A) voltage and the output side (B) of the second OP amplifier OP2. ), That is, the voltage across the tilt correction coil 10 is changed, and the direction and magnitude of the correction current are adjusted.

That is, when the input side A voltage of the second OP amplifier OP2 is smaller than the output side B voltage, the output side B voltage is converted into a current component through the resistor R6 and applied to the tilt correction coil 10 to be applied. On the tilt correction coil 10 Direction correction current flows.

On the contrary, if the input side A voltage of the second OP amplifier OP2 is greater than the output side B voltage, the input side A voltage is converted into a current component through the resistor R7 and applied to the tilt correction coil 10 to be tilted. On the correction coil 10 Direction correction current flows.

Accordingly, a magnetic field is generated according to the magnitude and direction of the correction current to change the deflection current direction, thereby correcting the tilt of the screen.

In addition, the apparatus of the present invention includes a clamping portion 43 composed of the first diode D1 and the second diode D2, so that the voltage supplied to the tilt correction coil 10 is only + Vcc to -Vcc. Restrict it to be variable.

Here, the capacitor C1 and the resistor R6 are time delay units, and prevent the current from being suddenly supplied to the tilt correction coil 10.

As described above, the apparatus of the present invention can change the direction of the deflection current by changing the voltage across the tilt correction coil 10 to change the direction and magnitude of the current flowing through the tilt correction coil, Since the screen tilt caused by the influence of the geomagnetic field can be easily corrected according to the present invention, the effect is great.

Claims (2)

A tilt correction coil 10 wound around the CRT net part and generating a magnetic field according to the magnitude of the flowing current to correct the tilt of the screen; A key input unit 20 through which a user inputs an up / down key to correct the tilt; A microcomputer 30 for outputting a correction signal whose level is variable according to the key input; And It is connected between both ends of the tilt correction coil 10, by changing the voltage across the tilt correction coil 10 in accordance with the correction signal to adjust the direction and magnitude of the current flowing through the tilt correction coil 10 Tilt correction circuit of the monitor, characterized by consisting of a current regulator (40). The method of claim 1, wherein the current control unit 40, A differential amplifier 41 which receives a correction voltage output from the microcomputer 30 and compares it with a reference voltage and amplifies the difference; After receiving and buffering the output signal of the differential amplifier 41, it is supplied to one end of the tilt correction coil 10, and the feedback input signal output from the other end of the tilt correction coil 10, input side And a buffer (42) for supplying current to the tilt correction coil due to the voltage difference between (A) and the output side (B).