KR19980085694A - Method and device for removing initial noise screen of LCD power supply - Google Patents

Abstract

end. The technical field to which the invention described in the claims belongs:

Initial noise screen elimination technology for power supply of liquid crystal display

I. The technical problem the invention is trying to solve:

Provided are a method and an apparatus for removing a noise screen generated when an initial power is applied to a liquid crystal display.

All. The gist of the solution of the invention:

After a certain period of time, the microcontroller responsible for automatic control of the electronic 0f electronic device equipped with the liquid crystal display detects the power-on of the electrical 0f electronic device and removes noise caused by the unstable operating state of the initial electrical 0f electronic device. The transistor is controlled on and off by applying a start pulse to the backlight lamp of the LCD to drive the LCD, or by discharging a fixed capacity electrolytic capacitor that operates at power-on without using a microcontroller of an electrical 0f electronic device. It consists of a constant DC voltage connected to or disconnected from the ground terminal by on / off operation and connecting the start pulse with an AND gate. The start pulse is controlled by the applied start pulse control unit to remove the start pulse when the circuit is powered on.

la. Important uses of the invention:

It is used to remove the noise screen output when the LCD is initially powered on.

Description

Method and device for removing initial noise screen of LCD power supply

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display (hereinafter referred to as an LCD). In particular, when power is first applied to a liquid crystal display, the backlight lamp of the backlight of the liquid crystal display is stably started, and then the backlight lamp is returned to a normal state. It relates to a backlight lamp driving circuit and method for driving.

In recent years, the use of LCDs, which are smaller and lighter than cathode ray tube displays, is increasing as screen displays.

In general, LCDs are light-receiving elements that do not emit light by themselves, and thus, by attaching a backlight having a high transmittance to the rear of the liquid crystal panel, it is possible to clearly view image information displayed on the LCD with uniform brightness. Usually, a backlight lamp is used as a light emitting means of the backlight. Backlight lamps are miniaturized fluorescent lamps for general lighting to match the backlight while maintaining the efficiency as possible.

Hereinafter, a conventional backlight structure, a backlight lamp driving circuit, and an operation thereof will be described with reference to the accompanying drawings.

1 is a schematic structural diagram of a general backlight. The backlight is disposed on the rear surface of the light guide plate 12 to emit light, a reflector 14 positioned below the light guide plate 12 to reflect light, a reflective film 16 to prevent light leakage from the side of the light guide plate 12, and The light guide plate 12 is disposed on the upper portion of the light diffusion plate 18 to uniformly diffuse.

When the light emitted from the backlight lamp 10 is incident inside through one side of the light guide plate 12, the light guide plate 12 transmits the incident light to the diffuser plate 18, and the diffuser plate 18 uniformly diffuses the light transmitted from the light guide plate 12 to the LCD. It is delivered to the panel to display the LCD.

The backlight lamp 10 is generally composed of positive and negative electrodes, mercury vapor, argon gas, and a fluorescent film applied to the outer surface of the lamp. When an electrical voltage is applied to the discharge electrode of the backlight lamp 10, the gases inside collide with each other by the activated electrons emitted from the cathode discharge electrode, and light is generated from the fluorescent film by blowing on the fluorescent film. In this case, in order to uniformly discharge the backlight lamp 10, a backlight driving circuit for applying a high voltage pulse to the backlight lamp 10 is required.

2 is a diagram illustrating a conventional backlight lamp 10 driving circuit. Referring to FIG. 1, a conventional backlight lamp 10 driving circuit receives a pulse generated by a pulse generator 20 that generates a pulse having a predetermined period, and a pulse generated by the pulse generator 20 under the control of a microcontroller (not shown). In the pulse section adjusting section 30 for adjusting the ratio of the high / low level section of the pulse, the high-pressure generating section 26 for generating a high pressure in accordance with the pulse applied from the pulse section adjusting section 30, The backlight lamp 10 emits light by the generated high pressure.

The pulse generator 20 is a timing generator IC and generates a pulse having a predetermined period and applies the pulse interval controller 30 to the pulse interval controller 30. The pulse interval controller 30 is applied to the pulse generator 20 when the initial power is applied under the control of the microcontroller. The high level state is adjusted to be longer and the low level state is adjusted to be shorter. After a predetermined time, the applied pulse is applied to the high voltage generator 26 without changing the high / low intervals. Thereafter, the high voltage generator 26 amplifies and converts the received pulse into a high voltage for driving the backlight lamp 10. Thereafter, the high pressure amplified and converted by the high pressure generator 26 is applied to the backlight lamp 10 so that the backlight lamp 10 emits light at a constant brightness.

The high / low section of the pulse generated by the pulse generator 20 determines the level of the high pressure at which the high pressure output from the high pressure generator 26 is applied to the backlight lamp 10. That is, high voltage is applied to the backlight lamp 10 when the pulse is in the high level state, and the longer the period of the pulse high level is, the higher the level of the high pressure applied to the backlight lamp 18 is and the higher the high voltage is applied to the backlight lamp 18. The period of the pulse is usually 15.71 so that the backlight lamp 10 has the appropriate brightness. s and the pulse width of the high level is 6.51 A pulse signal of s (hereinafter referred to as normal pulse) is used.

If the LCD is left for a certain time without using the LCD, the electrons in the backlight lamp 10 become inactive. In the backlight lamp 10 in the inactive state, the lamp does not emit light even when a high-pressure level is applied according to the normal pulse. Therefore, when the initial power is applied to the LCD, that is, when the initial power is applied to the backlight lamp 10, the high voltage of the level according to the pulse signal (hereinafter referred to as start pulse) where the high level pulse width is longer than the high level pulse width of the normal pulse. Is applied to activate electrons in the backlight lamp 10 to emit the backlight lamp 10.

Hereinafter, the configuration and operation of the spread interval control unit 30 for converting the normal pulse applied from the pulse generator 20 into the above-described starting pulse upon initial power-up will be described in detail with reference to the accompanying drawings.

As shown in FIG. 2, the pulse section adjusting unit 30 includes an integrating circuit unit 32 for extending the high level section of the pulse applied from the pulse generator 20, an enable unit 34 for enabling the integrating circuit unit 32, and an integrating circuit unit. It consists of a first inverter (INV1) 22 and a second inverter (INV2) 24 connected to an input terminal and an output terminal of 32, respectively.

If the input terminal of the first inverter 22 is node A, the output terminal is node B, and the input terminal of the second inverter 24 is node C, and the output terminal is node D, the integrating circuit unit 32 is the node B and the output terminal of the first inverter 22. A resistor R1 connecting the node C, the input terminal of the second inverter 24, a diode D1 connected in parallel with the resistor R1 and forming a pass path from the second inverter 24 to the first inverter 22, and one side is connected to the node C. The capacitor C1 is connected to the enable unit 24.

The enable unit 24 has an N-type first transistor Q1 and a first transistor, whose collector stage is connected to a 5 V input power supply VCC, the emitter stage is grounded through a resistor R2, and receives a control signal of a microcontroller to the base stage. It is connected to the emitter end of the Q1 and the base end, the collector end is connected to one end of the capacitor C1 of the integrating circuit unit 32, the emitter end is composed of a grounded N-type second transistor Q2.

The operation of the pulse interval control unit 30 will be described with reference to FIGS. 2 and 3.

3A and 3B are signal waveform diagrams of respective nodes according to the control signal of the microcontroller in FIG. 2. First, when the initial power is applied to the LCD, the microcontroller (not shown) that controls the overall operation of the device equipped with the LCD recognizes power on and typically a high signal of 5V for about 2 to 3 seconds. Is applied to the base end of the first transistor Q1 of the enable section 34 in the pulse duration control section 30. Then, the first transistor Q1 and the second transistor Q2 in the enable 34 are turned on in turn, and one side of the capacitor C1 in the integrated circuit unit 32 is connected to the ground terminal GND, so the integrated circuit unit 32 is disabled by the voltage chargeable state of the capacitor C1. It becomes an operational state.

On the other hand, as shown in Figure 3a, the pulse at the node A point applied to the pulse interval control unit 30 from the pulse generator 20 passes through the first inverter 22, the waveform is reversed at the node B point. When the pulse signal is changed from the low level to the high level at the node B point, the voltage of the pulse at the node C point charges the capacitor C1 connected to the ground terminal and becomes chargeable based on the control signal of the microcontroller. As shown by waveform C, the transition from the low level to the high level is relatively slow. That is, the capacitor C1 is charged using the values of the resistor R1 and the capacitor C1 as time constants. Thereafter, the pulse of the point C of the node is applied to the second inverter 24, and the pulse passing through the second inverter 24 generates a pulse in which the high level section is extended from the node D as shown in FIG. 3A to the high voltage generator 26. Is approved. At this time, the normally extended high level section is approximately 11.51 s. Normally, the high section of the normal pulse is 6.51 In case of s, the high pressure generated by the high-pressure generator 26 is about 1.7 KV, and the high section of the starting pulse is 11.51. At s, the high pressure generated at the high pressure generating part 26 is about 2.7 KV.

By applying a high voltage of 2.7KV to the backlight lamp 10, the photoelectrons in the backlight lamp are sufficiently activated.

The start pulse is applied to the high-pressure generator 26 to activate the photoelectrons of the backlight lamp 10 for a period of about 2 to 3 seconds after the initial power is applied. When the high pressure generated in the high pressure generating unit 26 by applying the starting pulse is applied to the backlight lamp 10 for approximately 2 to 3 seconds, the photoelectric of the backlight lamp 10 is sufficiently activated. Then, the microcontroller is enabled in the pulse section control unit 30. A low level signal is applied to the base terminal of the first transistor Q1 in 34. Then, the first transistor Q1 and the second transistor Q2 are turned off in turn, and accordingly, the connection between the capacitor C1 and the ground terminal in the integrating circuit section 32 connected to the collector terminal of the second transistor Q2 is disconnected, thereby making the capacitor C1 impossible to charge. .

Accordingly, the pulse generated by the pulse generator 20 is applied to the high voltage generator 26 while maintaining the high level of the initial pulse while passing through the first inverter 22, the resistor R1 and the second inverter 24 in the integrated circuit 32. 3B is a pulse waveform diagram of each node A, B, C, and D when the control signal of the microcontroller is at a low level. As shown in FIG. 3B, the waveform at node A, which is the waveform of the pulse generated by the pulse generator 20, passes through the first inverter 22 and the second inverter 24 to the high voltage generator 26 without fluctuation of the high level section. Is approved.

However, since the electric 0f electronic device equipped with the LCD normally does not operate normally during the first predetermined time (about 2 seconds) when the power is turned on, a color or noise screen that is not determined is output to the LCD during that time. These noise screens are not only visually aesthetical, but also reduce the reliability of LCD products to the user.

Accordingly, an object of the present invention is to provide a method and apparatus for removing a noise screen generated when an initial power is applied to an LCD.

In order to achieve the above object, the present invention provides a microcontroller in charge of automatic control of an electronic 0f electronic device equipped with an LCD, and detects the power-on of the electrical 0f electronic device. After a certain period of time for which the battery is removed, the LCD is driven by applying a start pulse to the backlight lamp of the LCD, or discharging the electrolytic capacitor of a certain capacity that is operated at power-on without using a microcontroller of an electrical 0f electronic device. It is composed of a constant DC voltage connected to or disconnected from the ground terminal by the on / off operation of the transistor controlled by the on / off and connecting the start pulse with an AND gate. The start pulse is circuit-powered by a start pulse control section that applies a low level signal to the AND gate. Characterized in that it removes a certain time on.

1 is a schematic structural diagram of a general backlight

2 is a diagram illustrating a conventional backlight lamp driving circuit.

3A and 3B are signal waveform diagrams of respective nodes according to the control signal of the microcontroller in FIG.

4 is a microcontroller control flowchart of a process of removing initial power-on noise screen of a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 5 is a comparison diagram of backlight lamp driving pulse waveforms according to the prior art and the exemplary embodiment of FIG. 4.

6 is a backlight lamp driving circuit diagram according to another embodiment of the present invention

7 is a comparison diagram of the backlight lamp driving pulse waveform according to FIG.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, specific matters such as components of a specific circuit are shown, which are provided to help a more general understanding of the present invention, and the specific matters may be modified or changed within the scope of the present invention. It will be obvious to those skilled in the art.

First, an embodiment of implementing the present invention using an internal microcontroller for automatically controlling the overall operation of a product having an LCD will be described. In particular, in the following description, the microcontroller has a function of controlling the output of the start pulse and the normal pulse by applying a control signal to the pulse interval control unit 30 as shown in FIG. 2.

4 is a microcontroller control flowchart of a process of removing an initial noise screen of applying power to an LCD according to an exemplary embodiment of the present invention. Referring to FIG. 4, the microcontroller first detects power-on of the electrical 0f electronic device in step 40. If the electrical 0f electronic device is powered on, the time count starts at step 41. This is to wait for the noise of the initial power-on of the electric 0f electronic device to disappear without applying the backlight lamp start pulse of the LCD immediately when the power source is turned on. Thereafter, in step 42, the microcontroller determines whether 2 seconds have elapsed since the power-on. This is because noise generated at the initial stage of power-on of the electric 0f electronic device disappears in about 2 seconds. In the exemplary embodiment of the present invention illustrated in FIG. 4, the standby time is 2 seconds, but the generation time of the noise due to the initial power supply varies slightly depending on the electrical 0f electronic device, and thus, may be set to another suitable standby time accordingly. The subsequent operation is similar to the conventional one. In step 43, the microcontroller outputs a control signal in a high level state to the enable unit 34 in the pulse interval control unit 30 as shown in FIG. 2 to generate a start pulse. After that, start the time count in step 44 and determine whether 2 seconds have elapsed in step 45. Then, in step 46, the low-level control signal is output to the enable unit 34 in the pulse interval control unit 30 to generate a normal pulse. To 26.

In the above process, the microcontroller applies the start pulse to the backlight lamp 10 of the LCD to drive the backlight after a predetermined time (2 seconds) when it is determined that the initial noise due to the power-on of the electrical 0f electronic device is removed. The screen will not be displayed on the LCD.

The driving pulse waveform of the backlight lamp 10 according to the above process will be described with reference to the accompanying drawings. FIG. 5 is a comparison diagram of a backlight lamp driving pulse waveform according to the related art and the exemplary embodiment of FIG. 4. The waveform D shown in FIG. 5 is a pulse waveform at a node D point of the conventional backlight lamp 10 driving circuit as shown in FIG. 2, and the waveform E is a pulse interval according to an embodiment of the present invention shown in FIG. 4. This is the output pulse waveform of the controller 30. First, the section 1 shown in FIG. 5 is a section for the first 2 seconds after the power-on of the first electric 0f electronic device. Conventional waveform D has a high level of normal pulses (1. longer than (s) s) The start pulse, but waveform E according to the invention is kept low level by the microcontroller during this period. The section 2, which is the first 2 seconds, followed by the section 2, which is the next 2 seconds, is converted to the normal pulse state because the waveform D is now sufficiently activated. However, the waveform E according to the present invention starts from the start pulse. It is converted to the state to activate the backlight lamp 10. Then, the waveform E according to the present invention is converted to the normal pulse state in the section ③. As a result, as shown in FIG. 5, when the waveforms D and E are compared with each other, the waveform E is displayed in a form in which the waveform D is delayed for 2 seconds.

Hereinafter, an embodiment of implementing the present invention without using an internal microcontroller for automatically controlling the overall operation of a product having an LCD will be described.

6 is a circuit diagram illustrating a backlight lamp 10 according to another embodiment of the present invention. 6, the pulse interval control unit 30 for controlling and outputting the start pulse and the normal pulse is briefly displayed. The pulse interval control unit 30 may be configured to be controlled by a microconverter as shown in FIG. 2, but the pulse generated in the pulse generator 20 is generated as a normal pulse after a predetermined time has elapsed after a predetermined time. For example, there are also electric 0f electronic devices that are simply configured appropriately circuitry. 6 shows an embodiment in which the present invention can be applied even in such a case.

Referring to FIG. 6, the driving circuit of the backlight lamp 10 according to another exemplary embodiment of the present invention provides a pulse generator 20 for generating a predetermined pulse and a high / high voltage of the input pulses by receiving the pulse generated by the pulse generator 20. The pulse interval control unit 30 for adjusting the ratio of the low level interval, the start pulse control unit 50 for removing a predetermined time at the initial power-on of the pulse applied by the pulse interval control unit 30 and the start pulse control unit 50 The high voltage generator 26 generates high pressure according to the pulse, and the backlight lamp 10 emits light by the high pressure generated by the high pressure generator 26.

The pulse generator 20 is a timing generator IC and generates a pulse having a predetermined width and applies it to the spread section controller 30. The spread section controller 30 applies the pulse applied from the pulse generator 20 at a high level when the initial power is applied. Longer, the low level state generates a shorter adjusted start pulse, and after a predetermined time, the applied pulse is applied to the start pulse control unit 50 without changing the high / low section. The starting pulse controller 50 removes the starting pulse from the applied pulse about 2 seconds at the initial power-on. This is to start the backlight lamp 10 of the LCD after waiting for the initial noise generated at the initial power-on of the electronic 0f electronic device to disappear. In one embodiment of the present invention, after the start pulse generated in the pulse interval control unit 30 at the initial power-on is removed for about 2 seconds, the start pulse is applied to the high pressure generator 26, and the start pulse is used to activate the photoelectrons of the backlight lamp 10. In general, the start pulse generated by the pulse interval control unit 30 should be generated about 4 to 5 seconds because it should be applied for about 2-3 seconds. Thereafter, the high voltage generator 26 amplifies and converts the received pulse into a high voltage for driving the backlight lamp 10. Thereafter, the high pressure amplified and converted by the high pressure generator 26 is applied to the backlight lamp 10 so that the backlight lamp 10 emits light at a constant brightness.

Hereinafter, the configuration of the start pulse control unit 50 for removing the start pulse applied by the pulse generator 20 at the time of initial power application will be described in detail.

Referring to FIG. 6, the starting pulse controller 50 includes an electrolytic capacitor C2 connected to a DC terminal and a positive terminal, a resistor R1 and R2 connected in series to connect a negative terminal and a ground terminal of the electrolytic capacitor C2, and the electrolytic capacitor C2 at a ground terminal. The diode D2, which forms a path to the negative stage, is connected between the resistors R1 and R2 and the base stage, and the collector stage is connected through the DC power supply VCC and the resistor R5, and the emitter stage is grounded N-type transistor Q3, The collector terminal of transistor Q3 is connected to one of the two input terminals, the other input terminal is connected to the output terminal of the pulse interval control unit 30, and the output terminal is composed of an end gate 52 connected to the input terminal of the high voltage generator 26.

FIG. 7 is a waveform diagram of a backlight lamp 10 driving pulse according to FIG. 6. The operation of the start pulse controller 50 will be described with reference to FIGS. 6 and 7.

During the section ⓐ shown in FIG. 7 for the first two seconds after the initial power is applied to the start pulse control unit 50 when the electronic device is powered on, the charge charged in the electrolytic capacitor C2 is transferred through the resistors R3 and R4. Is discharged and turns on transistor Q3. When the transistor Q3 is turned on, the DC input voltage VCC applied through the resistor R5 is discharged through the collector terminal and the emitter terminal of the transistor Q3. Accordingly, a low level signal is input to the input terminal of the AND gate 52 connected to the collector terminal of the transistor Q3 (point F in FIG. 6) as shown by the signal F in FIG. 7. At this time, the start pulse is output from the pulse interval control unit 30 and the high level state is longer than the normal pulse state is input to the type force stage (point D of FIG. 6) of the AND gate 52 as shown by the signal D in FIG. Accordingly, during the period ⓐ, a low level signal is output to the output terminal (point G in FIG. 6) of the AND gate 52 as shown by the signal G in FIG. 7. The output signal G is applied to the high pressure generator 26 so that the high pressure generator 26 does not operate at all. Therefore, the backlight lamp 10 is not driven during the first two seconds after the power-on of the electronic 0f electronic device, so that the noise screen is not displayed on the LCD.

In an embodiment of the present invention shown in FIG. 6, the transistor Q3 is turned on by the discharge of the electrolytic capacitor C2, and the low level signal is input to one input terminal of the AND gate by discharging the DC input voltage to the ground terminal. Therefore, the period of 2 seconds means that the transistor Q3 is turned on, that is, the discharge time of the electrolytic capacitor C2. Therefore, the electrolytic capacitor C2 is set in advance to a capacity capable of applying an appropriate discharge current to the base terminal of the transistor Q3 so that the transistor Q3 can be kept on for only 2 seconds. In addition, since the generation time of the noise due to the initial power supply varies slightly depending on the electric 0f electronic device, the electrolytic capacitor C2 is set in advance to a capacity capable of discharging for a suitable time.

When the discharge of the electrolytic capacitor C2 is completed, the transistor Q3 is turned off and the DC voltage VCC input through the resistor R5 is not discharged to the ground terminal but is applied to the input terminal of the AND gate. Therefore, as shown in FIG. 7, the signal F is at a high level from the section ⓑ, and thus the output signal G of the AND gate 52 is equal to the starting pulse D output from the pulse duration controller 30 and applied to the AND gate 52. The output signal G is applied to the high voltage generator 26 to generate a high voltage for activating the photoelectron of the backlight lamp 10.

Since the pulse interval control unit 30 generates the starting pulse for only 4 seconds according to an embodiment of the present invention, the normal pulse is input to the input terminal D of the AND gate 52 from the section ⓒ after the ⓑ section for 2 seconds, and then goes to the output terminal of the AND gate 52. As shown in section ⓒ of FIG. 7, the output signal G outputs the same pulse as the normal pulse of the input signal D.

After a certain time (2 seconds) when the initial noise caused by the power-on of the electrical 0f electronic device is removed by the circuit described above, a startup pulse is applied to the backlight lamp 10 of the LCD to drive the backlight. It is not displayed.

Therefore, the present invention is a time when the microcontroller in charge of automatic control inside the electronic 0f electronic device provided with the LCD detects the power-on of the electrical 0f electronic device to remove noise due to the unstable operation state of the initial electrical 0f electronic device. After waiting for a time, the driving pulse is applied to the backlight lamp of the LCD to drive the LCD, or the on / off control is performed by discharging a fixed capacity electrolytic capacitor that is operated at power-on without using a microcontroller of an electronic 0f electronic device. It is composed of connecting a constant DC voltage and a start pulse connected to the ground terminal or starting pulse by an AND gate by the on / off operation of the transistor, and applying a low level signal to the AND gate for a predetermined time at the initial power-on. The start pulse control unit removes the start pulse when the circuit is powered on for a certain time. There is an advantage to remove the noise screen generated when the power is applied.

Claims (16)

In the method for removing the noise screen displayed on the liquid crystal display due to noise generated for a predetermined time in the initial power-on of the electrical 0f electronic device having a liquid crystal display, And a driving voltage is applied to a backlight lamp of the liquid crystal display after waiting for a predetermined time in the initial stage of power-on of the electrical 0f electronic device to drive the liquid crystal display after the noise disappears. The method of claim 1, wherein the predetermined time waiting time is 2 to 3 seconds. The method of claim 1, wherein the driving voltage of the backlight lamp is about twice higher than the voltage applied to the backlight lamp in a normal operation state for the first predetermined time. The method of claim 1, wherein the applying of the driving voltage to the backlight lamp after the predetermined time wait is performed by a controller that controls the overall automatic operation of the electrical 0f electronic device provided in the electrical 0f electronic device. A noise screen removal method characterized by the above-mentioned. And a pulse period adjusting unit for controlling the controller to output a start pulse for a predetermined time and then output a normal pulse at the time of initial driving to the backlight lamp of the liquid crystal display by a control unit, and a pulse output from the pulse period adjusting unit. When the start pulse is applied to apply a high-voltage pulse for activating the backlight lamp to the backlight lamp, when the normal pulse is applied to the high-voltage generator for applying a second high voltage pulse to stabilize the backlight lamp In the method for removing the noise screen displayed on the liquid crystal display by the noise generated for a predetermined time in the initial power-on of the electrical 0f electronic device provided, Waiting for the predetermined time at an initial stage of power-on of the electrical 0f electronic device to drive the liquid crystal display after the noise disappears; Controlling the pulse duration adjusting unit so that the starting pulse is applied to the high pressure generating unit for a predetermined time after the predetermined time waiting; And controlling the pulse duration adjusting unit so that the normal pulse is applied to the high voltage generating unit after the starting pulse is applied to the back lamp for a predetermined time. The noise screen removing method of claim 5, wherein a predetermined waiting time is 2 to 3 seconds at an initial stage of power-on of the electrical 0f electronic device. The method of claim 5, wherein the first high voltage pulse has a voltage level twice higher than that of the second high pressure pulse. 6. The method of claim 5, wherein the predetermined time waiting for the initial power-on of the electrical 0f electronic device is started immediately after the power-on of the electrical 0f electronic device is started and the time count is reached when a predetermined time is reached. Noise screen removal method The noise screen removing method of claim 5, wherein the predetermined time period for which the start pulse is applied to the high-pressure generator is 2 to 3 seconds. And a pulse period adjusting unit for controlling the controller to output a start pulse for a predetermined time and then output a normal pulse at the time of initial driving to the backlight lamp of the liquid crystal display by a control unit, and a pulse output from the pulse period adjusting unit. When the start pulse is applied to apply a high-voltage pulse for activating the backlight lamp to the backlight lamp, when the normal pulse is applied to the high-voltage generator for applying a second high voltage pulse to stabilize the backlight lamp An apparatus for removing a noise screen displayed on the liquid crystal display by noise generated for a predetermined time in the initial stage of power-on of an electric 0f electronic device provided therein, After the noise disappears, the start pulse control unit for ANDing the start pulse output from the pulse duration control unit and a low level state during the initial power-on of the electric 0f electronic device to drive the liquid crystal display. Noise screen removal device, characterized in that provided. The noise screen removing apparatus of claim 10, wherein the initial power-on predetermined time is 2 to 3 seconds. The apparatus of claim 10, wherein the start pulse output from the pulse duration control unit is output for 4 to 5 seconds. 11. The method of claim 10, wherein the low-level signal during the initial power-on of the electric power 0f electronic device by the discharge current of the electrolytic capacitor of a predetermined capacity to perform a discharge operation for a predetermined time when the power of the electric power 0f electronic device. And a switch element that is turned on to form a discharge path to a ground of a predetermined DC input voltage, and a signal output from a node between the DC input voltages. And a pulse period adjusting unit for controlling the controller to output a start pulse for a predetermined time and then output a normal pulse at the time of initial driving to the backlight lamp of the liquid crystal display by a control unit, and a pulse output from the pulse period adjusting unit. When the start pulse is applied to apply a high-voltage pulse for activating the backlight lamp to the backlight lamp, when the normal pulse is applied to the high-voltage generator for applying a second high voltage pulse to stabilize the backlight lamp An apparatus for removing a noise screen displayed on the liquid crystal display by noise generated for a predetermined time in the initial stage of power-on of an electric 0f electronic device provided therein, An electrolytic capacitor having a predetermined capacity performing a discharge operation for a predetermined time when the electric 0f electronic device is powered on; A switch element that is turned on by the discharge current of the electrolytic capacitor and forms a discharge path to the ground of a predetermined DC input voltage; The output terminal of the pulse interval control unit and one input terminal are connected to receive a pulse output from the pulse interval control unit, and the other input terminal is connected between the DC input voltage and the switch element to provide the DC input voltage during the discharge time of the electrolytic capacitor. And a low state signal is received by the discharge to the ground, and the output terminal comprises an AND gate connected to the high voltage generator. 15. The apparatus of claim 14, wherein the initial power-on predetermined time is 2 to 3 seconds. 15. The apparatus of claim 14, wherein a start pulse output from the pulse duration control unit is output for 4 to 5 seconds.