KR100705632B1 - Liquid crystal display device having after-image removal function - Google Patents

Abstract

The disclosed liquid crystal display device having an afterimage removing function includes a liquid crystal panel including a liquid crystal panel, a backlight unit disposed on a rear surface of the liquid crystal panel, a driving circuit unit for applying a driving signal to the liquid crystal panel, and a chassis unit for assembling the liquid crystal panel and the backlight unit; It is provided on one side of the liquid crystal display module and provided with an afterimage removing unit for removing the afterimage generated in the liquid crystal panel by the magnetic field, and according to the liquid crystal display device having the afterimage removal function of this structure is the cause of the afterimage occurrence during image change By rearranging the ions accumulated at the interface between the alignment layer and the liquid crystal cell by the magnetic field, an afterimage may be removed.

LCD, afterimage

Description

Liquid crystal display device having after-image removal function

1 is a schematic cross-sectional view showing a liquid crystal display device having an afterimage removing function according to an embodiment of the present invention;

2 is a block diagram showing the afterimage removing unit of FIG.

3A and 3B are diagrams illustrating an afterimage disappearing process by the electromagnet of FIG. 1;

<Description of the symbols for the main parts of the drawings>

10 ... LCD 20.LCD Module

30 ... LCD panel 40 ... Drive circuit

50 ... Backlight 60 ... Chassis

70 ... image retention unit 71 ... electromagnet

72 ... drive section 72a ... drive section

72b ... heat drive 80 ... alignment layer

90 ... liquid crystal cell

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having an afterimage removal function capable of removing an afterimage frequently generated in a liquid crystal display device used for a monitor or a cathode ray tube.

In general, a liquid crystal display device is an electronic device that changes and transmits various electrical information generated by various devices into visual information by using a change in transmittance of liquid crystal according to an applied voltage. An information display window of a portable terminal and a screen display of a notebook computer are used. It is used as an information display window.

However, such a conventional liquid crystal display device has a problem that a previous image pattern called an afterimage remains frequently when a specific still image is driven for a predetermined time and then another image is to be displayed.

Such afterimages occur because the alternating voltage is applied to the liquid crystal cell and the blocking is repeated, and thus the electric double layer is formed by accumulating the DC voltage component in the liquid crystal cell and adsorbing the alignment film due to the difference in the dielectric constant in the liquid crystal. That is, when ions in the liquid crystal cell are arranged at a predetermined position in order to realize a specific image and then display another image, afterimages are generated because ions of DC voltage components accumulated while implementing the previous image are not rearranged. It happens. Here, since the liquid crystal display, the liquid crystal cell, and the alignment layer are general technologies, detailed description thereof will be omitted.

Therefore, the frequent occurrence of such an afterimage in the liquid crystal display has a problem of degrading the quality and reliability of the product.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has an object of improving the quality and reliability of a product by removing afterimages frequently generated in liquid crystal displays.

The liquid crystal display device having an afterimage removing function of the present invention for achieving the above object includes a liquid crystal panel, a backlight unit provided on the rear surface of the liquid crystal panel, a driving circuit unit for applying a driving signal to the liquid crystal panel and the liquid crystal panel. A liquid crystal display module including a chassis to assemble a panel and the backlight unit; And an afterimage removing unit installed at one side of the liquid crystal display module to remove an afterimage generated in the liquid crystal panel by a magnetic field formed by an electromagnet.

Here, the afterimage removing unit includes a plurality of electromagnets for forming a magnetic field to change positions and energy states of ions causing afterimages in the liquid crystal panel, a driving unit for applying current to form a magnetic field in the plurality of electromagnets, and the driving unit. It is preferable to include a control unit for controlling.

In addition, the plurality of electromagnets are preferably arranged in a matrix.

In addition, the driving unit preferably includes a row driving unit provided on the row side of the matrix arrayed electromagnets and a column driving unit provided on the column side.

In addition, each of the row driving unit and the column driving unit may independently apply a current to each of the plurality of electromagnets.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic cross-sectional view of a liquid crystal display device having an afterimage removing function according to an exemplary embodiment of the present invention.

Referring to the drawings, the liquid crystal display device 10 having an afterimage removing function includes a liquid crystal display module 20 and an afterimage removing unit 70.

The liquid crystal display module 20 includes a liquid crystal panel 30, a backlight unit 50 disposed on a rear surface of the liquid crystal panel 30, and a driving circuit unit 40 for applying a driving signal to the liquid crystal panel 30. ) And a chassis 60 for assembling the liquid crystal panel 30 and the backlight unit 50. Here, the liquid crystal display module 20 is generally used, and drawings thereof will be omitted, and each component will be briefly described.

The liquid crystal panel 30 includes a lower glass substrate on which a thin film transistor array is formed, an upper glass substrate on which a color filter is formed, and a liquid crystal cell provided by a liquid crystal injected between the lower glass substrate and the upper glass substrate.

The lower glass substrate is provided with a thin film transistor as a switching element and a pixel electrode for applying a signal voltage applied through the thin film transistor to the liquid crystal cell.

The upper glass substrate is provided with a color filter and a common electrode for applying a voltage to the liquid crystal cell.

An alignment layer for aligning the liquid crystal is formed on a surface where each of the lower glass substrate and the upper glass substrate contacts the liquid crystal, and a polarizing plate is attached to the opposite surface on which the alignment film is formed. Here, the lower glass substrate and the upper glass substrate are twisted 90 ° to each other, and the liquid crystal molecules in the liquid crystal cell are continuously twisted at 90 ° between the upper and lower glass substrates.

The driving circuit unit 40 converts the video signal temporally and spatially and supplies the voltage level corresponding to each pixel to the liquid crystal panel 30 through respective wirings.

The backlight unit 50 scans, as a light source, planar light with uniform brightness onto the liquid crystal panel 30.

The chassis unit 60 is a frame for making the liquid crystal panel 30, the driving circuit unit 40, and the backlight unit 50 into one assembly.

The liquid crystal constituting the liquid crystal cell controls the transmission degree of the white plane light emitted from the backlight unit 50 by changing its molecular structure according to the applied voltage.

The liquid crystal display module 20 controls the light transmitted through the white plane light incident from the backlight unit 50 to the liquid crystal panel 30 according to the signal voltage of each pixel input from the driving circuit unit 40. Color image will be realized.

That is, when the backlight unit 50 irradiates the white plane light to the liquid crystal cell, the white plane light does not pass through the liquid crystal due to the liquid crystal molecules that are continuously twisted by 90 ° in a state in which no voltage is applied.

At this time, when a voltage is applied to the liquid crystal by using the thin film transistor, the liquid crystal having a molecular arrangement of 90 ° twisted state is aligned in one direction perpendicular to the upper and lower glass substrates while the twisted state is released and the white plane light is transmitted straight through. Here, the amount of transmission of the white plane light entering the liquid crystal is adjusted according to the degree of twisting and unwinding of the alignment direction of the liquid crystal molecules, and the degree of twisting and unwinding of the alignment direction of the liquid crystal molecules is controlled by the applied voltage.

The white plane light thus passed is provided to the pixels of the color filter to implement a desired image.

The afterimage removal unit 70 is installed outside the chassis 60 at the portion where the backlight 50 is installed, and includes a plurality of electromagnets 71, a driver 72, and a controller 73 as shown in FIG. 2. .

Electromagnets 71 are for forming a magnetic field by receiving a current from the driving unit 72 controlled by the control unit 73, are arranged in a matrix, the magnetic field generated by the electromagnets 71 is a liquid crystal The force is applied to the display module 20, particularly inside the liquid crystal cell.

The driving unit 72 is for applying a current to the electromagnets 71 to form a magnetic field in the electromagnets 71. The driving unit 72 is a row driving unit 72a and a column driving unit on the row side and the column side of the electromagnet 71 arranged in a matrix. 72b).

Each of the row driver 72a and the column driver 72b selectively and independently applies a current to the plurality of electromagnets 71 so that a magnetic field is complexly generated in the plurality of electromagnets 71. As such, when the magnetic field is complicated, the arrangement direction of the ions, which is the cause of the afterimage to be described later, may be easily rearranged.

According to the liquid crystal display device 10 having the afterimage removing function having such a structure, an alternating voltage is applied to the liquid crystal cell 80 as shown in FIG. 3A so that the DC voltage component is formed at the interface between the alignment layer 90 and the liquid crystal cell 80. When the ions accumulate and the previous image remains as an afterimage when the image is changed, the control unit 73 operates the driving unit 72 to send a current to the electromagnets 71.

Then, a magnetic field is formed in the electromagnets 71, and the magnetic field exerts its force to the liquid crystal cell 80 as shown in FIG. 3B, and the ion of the DC voltage component accumulated at the interface between the alignment layer 90 and the liquid crystal cell 80. Rearrange them so that afterimages do not occur when the image changes.

As described above, since the magnetic field is complicated by the plurality of electromagnets 71, the ions of the DC voltage component accumulated at the interface between the alignment layer 90 and the liquid crystal cell 80 may be easily rearranged.

According to the liquid crystal display device having the afterimage removal function of the present invention as described above, an afterimage removal unit having an electromagnet is installed in the liquid crystal display device, and accumulates at the interface between the alignment film and the liquid crystal cell that cause afterimage change when the image is changed. By rearranging the ions by the magnetic field it can provide an effect that can eliminate the afterimage generation.

It is to be understood that the invention is not limited to that described above and illustrated in the drawings, and that more modifications and variations are possible within the scope of the following claims.

Claims (5)

A liquid crystal display module including a liquid crystal panel, a backlight unit disposed on a rear surface of the liquid crystal panel, a driving circuit unit for applying a driving signal to the liquid crystal panel, and a chassis unit for assembling the liquid crystal panel and the backlight unit; And And an afterimage removing unit installed on one side of the liquid crystal display module to remove an afterimage generated in the liquid crystal panel by a magnetic field formed by an electromagnet. The method of claim 1, The afterimage removing unit controls a plurality of electromagnets for forming a magnetic field to change positions and energy states of ions causing afterimages in the liquid crystal panel, a driver for applying a current to form a magnetic field in the plurality of electromagnets, and the driving unit. Liquid crystal display device having an afterimage removal function comprising a control unit. The method of claim 2, And said plurality of electromagnets are arranged in a matrix. The method of claim 3, And the driving part comprises a row driving part provided on the row side of the matrix-magnet electromagnet and a column driving part provided on the column side. The method of claim 4, wherein And each of the row driver and the column driver independently applies a current to each of the plurality of electromagnets.

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