KR100744392B1 - Liquid crystal display device - Google Patents

Abstract

An LCD is provided to reduce the number of interfaces between an observer and a liquid crystal layer of a light shutter part, thereby suppressing the deterioration of display quality due to loss of light, by forming a polarizing plate on an ITO(Indium Tin Oxide) electrode of an upper substrate for the light shutter part in a slit type. An LCD comprises an image display part(110) and a light shutter part(120) facing the image display part. The image display part includes a display liquid crystal layer(111), first upper and lower substrates(112,113) formed at both sides of the display liquid crystal layer, a first polarizing plate(114) formed on the first lower substrate, and a second polarizing plate(115) formed on the first upper substrate. The light shutter part includes a second upper substrate(122), a second lower substrate(123), and a light shutter liquid crystal layer(121) interposed between the second upper substrate and the upper lower substrate. ITO electrodes(124) are respectively formed on opposite faces of the second upper substrate and the second lower substrate. A third polarizing plate(125) is formed on the ITO electrode of the second upper substrate in a slit type.

Description

Liquid crystal display device

1 is an exploded cross-sectional view showing a conventional liquid crystal display device;

2A and 2B are cross-sectional views illustrating operations of the optical shutter unit and the optical compensation unit of FIG. 1 according to whether voltage is applied;

3 is an exploded cross-sectional view showing a liquid crystal display device according to an embodiment of the present invention;

4A and 4B are cross-sectional views illustrating operations of the optical shutter unit of FIG. 3 according to whether voltage is applied in a normal black VA mode;

5A and 5B are cross-sectional views illustrating the operation of the optical shutter unit of FIG. 3 according to whether voltage is applied in a depleted white TN mode.

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

100 ... LCD Display 110 ... Image Display

115 ... second polarizer 120 ... optical shutter

121 ... optical shutter liquid crystal layer 122 ... second upper substrate

123 ... second lower substrate 124 ... ITO electrode

125. The third polarizer

The present invention relates to a liquid crystal display, and more particularly, to a liquid crystal display capable of realizing a two-dimensional and three-dimensional image by a parallax barrier method.

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 a liquid crystal according to an applied voltage. An information display window of a portable terminal, a screen display of a notebook computer, etc. It is used as an information display window.

Such LCDs mainly display two-dimensional images. Recently, as the display characteristics of LCDs have improved, technologies for displaying three-dimensional images in three dimensions have been developed. Two-dimensional images and three-dimensional images have been developed. Techniques for selectively converting images according to the needs of users are being developed.

1 is a cross-sectional view of a liquid crystal display capable of selectively converting a 2D image and a 3D image using a conventional parallax barrier method.

Here, the parallax barrier method to be described in FIG. 1 is a kind of a method of converting a 2D image or a 3D image to be selectively displayed. In this case, even if the user does not wear special glasses having polarization characteristics, When the image with binocular disparity is presented on the same plane, the image is divided into left and right, so that the human eye can feel a three-dimensional effect.

Referring to the drawing, the liquid crystal display device 10 includes an image display unit 20, an optical shutter unit 30, and an optical compensator 40.

The image display unit 20 includes a liquid crystal panel 21 and first and second polarizing plates 22 and 23 provided on both sides of the liquid crystal panel 21.

The optical shutter unit 30 is provided on the liquid crystal layer 31 and above and below the liquid crystal layer 31, and the upper and lower substrates 32 and 33 on which the ITO electrode 34 is formed on the surface facing the liquid crystal layer 31. The third substrate 35 is provided on one side of the lower substrate 33 and has an optical axis orthogonal to the optical axis of the second polarizing plate 23.

Here, the ITO electrode 34 provided on the lower substrate 33 is provided only in a part of the lower substrate 33.

Therefore, when a voltage is applied to the ITO electrode 34 provided in the optical shutter unit 30, no electric field is formed in the liquid crystal molecules 31a on the region where the ITO electrode 34 is not provided on the lower substrate 33. Therefore, there is no change in the arrangement of the liquid crystal molecules 31a, and an electric field is formed on the liquid crystal molecules 31a on the ITO electrode 34 provided on the lower substrate 33 so that the arrangement direction of the liquid crystal molecules 31a is at a predetermined angle. Is tilted.

The optical compensation unit 40 is interposed between the image display unit 20 and the optical shutter unit 30, and is divided into a 0 ° phase difference unit 42 and a λ / 2 phase difference unit 41, and a 0 ° phase difference unit 42. ) Is provided in an area corresponding to the ITO electrode 34 of the lower substrate 33, and the λ / 2 phase difference part 41 is provided in an area where the ITO electrode 34 of the lower substrate 33 does not exist.

In the liquid crystal display device 100 having such a structure, as shown in FIG. 2A, when the voltage is applied to the optical shutter unit 30, the operation relationship between the optical shutter unit 30 and the optical compensator 40 will be described. Light incident from (not shown) is polarized by the third polarizing plate 35 to be sent to the liquid crystal layer 31, where light incident on the lower substrate 33 to the region without the ITO electrode 34 is a liquid crystal. Since there is no change in the arrangement direction of the molecules 31a, the light emitted to the light compensator 40 as it is and incident to the region where the ITO electrode 34 on the lower substrate 33 exists is tilted of the liquid crystal molecules 31a. By polarizing by λ / 2 is emitted to the light compensation unit 40.

The light passing through the region where the ITO electrode 34 exists on the lower substrate 33 among the light incident to the optical compensation unit 40 passes through the 0 ° phase difference unit 42 and passes through the second polarizing plate 23. The light emitted and passing through the region where the ITO electrode 34 does not exist on the lower substrate 33 is polarized through the λ / 2 phase difference part 41 and is emitted through the second polarizing plate 23.

When the voltage is not applied to the optical shutter unit 30 as shown in FIG. 2B, there is no change in the arrangement direction of the liquid crystal molecules 31a, so that the ITO electrode 34 is not provided on the lower substrate 33. Light incident from the backlight unit does not pass.

Therefore, when the 3D image is to be viewed, light is applied to the optical shutter unit 30 so that a part of the image display unit 20 is provided with light, and when the 2D image is to be viewed, the optical shutter unit 30 is provided. A voltage is applied to all the light so as to be provided to the image display unit 20.

However, the liquid crystal display device 10 having such a structure provides an observer from the liquid crystal layer 31 of the optical shutter unit 30 by providing a light compensating unit 40 for adjusting the phase difference of incident light in order to selectively control light transmission. Increasing the interface therebetween, the display quality of the screen is reduced due to light loss due to reflection at the interface, etc., and the manufacturing process of the liquid crystal display device 10 is complicated by inserting the optical compensation unit 40. There is a problem.

Accordingly, the present invention has been made to solve the above problems, and improved liquid crystal display device using a parallax barrier method for realizing 2D and 3D images to prevent deterioration of display quality of the screen and to simplify the manufacturing process. Its purpose is to provide.

The liquid crystal display device of the present invention for achieving the above object, the display liquid crystal layer, the first upper and lower substrates provided on both sides of the display liquid crystal layer, the first polarizing plate and the first upper substrate provided on one side of the first lower substrate An image display unit having a second polarizing plate provided on the other side; And an optical shutter unit provided on the other side of the image display unit and having an optical shutter liquid crystal layer interposed between the second upper substrate and the second lower substrate and the second upper substrate and the second lower substrate. In the liquid crystal display device, the second upper substrate and the second lower substrate are each provided with an ITO electrode on the entire surface facing each other, the third polarizing plate on the ITO electrode provided on the second upper substrate in a slit form. Characterized in that provided.

Here, the liquid crystal molecules of the optical shutter liquid crystal layer are positive liquid crystal molecules, and the optical axis of the second polarizing plate is orthogonal to the optical axis of the third polarizing plate provided on the ITO electrode.

In addition, the liquid crystal molecules of the optical shutter liquid crystal layer are negative liquid crystal molecules, and the optical axis of the second polarizing plate is preferably parallel to the optical axis of the third polarizing plate provided on the surface of the ITO electrode.

(Example)

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

3 is a cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to the drawings, the liquid crystal display device 100 is provided with an image display unit 110 for displaying a screen, and is provided above or below the image display unit 110, and controls the transmission of light incident from a backlight unit (not shown). The optical shutter unit 120 is included.

In the present invention, the optical shutter 120 is provided on the upper portion of the image display unit 110 will be described as an example.

The image display unit 110 includes a display liquid crystal layer 111, first upper and lower substrates 112 and 113 provided at both sides of the display liquid crystal layer 111, a first polarizing plate 114 provided at one side of the first lower substrate 113, and The second polarizer 115 is provided on the other side of the first upper substrate 112.

Since the image display unit 110 is a general content of the liquid crystal panel of the liquid crystal display device for displaying a two-dimensional image, a detailed description thereof will be omitted.

The optical shutter unit 120 includes an optical shutter liquid crystal layer 121 and third polarizers 125 provided on one side of the second upper and lower substrates 122 and 123 and the second upper substrate 122 provided on both sides of the optical shutter liquid crystal layer 121. ).

On the surfaces of the second upper and lower substrates 122 and 123 facing the optical shutter liquid crystal layer 121, the ITO electrodes 124 are formed in a box shape, that is, the front surfaces of the second upper and lower substrates 122 and 123 are provided. .

The third polarizer 125 is provided in the form of slits in which a plurality of third polarizers 125 are spaced apart from each other at predetermined intervals on the ITO electrode 124 of the second upper substrate 122.

At this time, the optical axis of the third polarizing plate 125 provided on the ITO electrode 124 is orthogonal or parallel to the optical axis of the second polarizing plate 115.

Here, when the optical axis of the third polarizing plate 125b provided on the ITO electrode 124 of the second upper substrate 122 is orthogonal to the optical axis of the second polarizing plate 115, the positive liquid crystal is formed on the optical shutter liquid crystal layer 121. Molecules are provided, and the parallel case is a case where negative liquid crystal molecules are provided in the optical shutter liquid crystal layer 121.

The reason for providing the third polarizing plate 125 in the optical shutter liquid crystal layer 121 is to reduce the occurrence of the interface between the image display unit 110 and the observer and to suppress the reflection phenomenon of light generated at the interface. It is to improve the elegance.

The operation of the optical shutter unit according to whether a voltage is applied in the liquid crystal display device having the above structure is as follows.

First, as shown in FIG. 4A, when the liquid crystal display device 100 is in the normal black VA mode, that is, when the liquid crystal molecules 121a of the optical shutter liquid crystal layer 121 are formed of negative liquid crystal molecules, the second upper and lower substrates 122 and 123 may be provided. When no voltage is applied to the ITO electrode 124, since the molecular arrangement of the liquid crystal molecules 121a is maintained, the second polarizing plate may be a portion of the second upper substrate 122 without the third polarizing plate. The polarized incident light is emitted as it is, and since the optical axis of the incident light and the optical axis of the third polarizing plate are parallel to the portion where the second polarizing plate is provided, the incident light is emitted through the third polarizing plate.

However, when voltage is applied to the ITO electrodes 124 provided on the second upper and lower substrates 122 and 123 as shown in FIG. 4B, the phase difference of the liquid crystal molecules 121a present in the optical shutter liquid crystal layer is changed by λ / 2.

Accordingly, incident light generated by the third polarizing plate is blocked by the third polarizing plate while passing through the optical shutter liquid crystal layer to the region where the third polarizing plate is present on the second upper substrate, and the incident light is directly provided to the region where the third polarizing plate is not present. It is emitted.

Therefore, in the normal black VA mode, a voltage is applied to the optical shutter unit 120 to implement a 3D image, and a voltage is not applied to the optical shutter unit 120 to implement a 2D image. Since it is not necessary, the 3D image or the 2D image may be selectively displayed depending on whether the voltage of the optical shutter unit 120 is applied.

Next, as shown in FIG. 5A, when the liquid crystal display device 100 is in the normal white TN mode, that is, when the liquid crystal molecules 121a of the optical shutter liquid crystal layer 121 are made of positive liquid crystal molecules, the liquid crystal display device 100 may be formed on the second upper and lower substrates 122 and 123. When no voltage is applied to the provided ITO electrode 124, the liquid crystal molecules of the optical shutter liquid crystal layer are all emitted regardless of the presence or absence of the third polarizer because the arrangement direction is not changed.

However, when a voltage is applied to the ITO electrodes 124 provided on the second upper and lower substrates 122 and 123 as shown in FIG. 5B, the liquid crystal molecules 121a of the optical shutter liquid crystal layer are changed in phase by λ / 2, and thus, the second polarizing plate. The incident light polarized by the 115 is emitted as it is without the third polarizing plate, and the portion provided with the third polarizing plate is orthogonal to each other because the optical axis of the third polarizing plate passes through the optical axis and the optical shutter liquid crystal layer. The incident light is blocked by the third polarizing plate.

In the liquid crystal display device 100 of the normal white TN mode, a voltage is applied to the optical shutter unit 120 to implement a 3D image, and a voltage is applied to the optical shutter unit 120 to implement a 2D image. By not applying the 2D or 3D image can be selectively displayed.

The liquid crystal display device 100 having such a structure selectively implements a 2D image and a 3D image by providing a third polarizing plate in the form of slits spaced apart from each other at predetermined intervals on the ITO electrode of the second upper substrate. By distinguishing the white and black implementation of the light emitted from the optical shutter unit, it is possible not only to display two-dimensional and three-dimensional images without additional components or processes, but also between the liquid crystal layer of the optical shutter unit and the observer. It is possible to reduce the display quality degradation of the screen due to light loss by reducing the number of interfaces present in the.

As described above, according to the liquid crystal display of the present invention, white and black implementations of light emitted from the optical shutter unit are distinguished by providing a third polarizing plate in the form of slits spaced apart from each other at predetermined intervals on the ITO electrode of the second upper substrate. This enables not only to display two-dimensional and three-dimensional images without additional components or processes, but also to reduce the number of interfaces existing between the liquid crystal layer and the observer in the optical shutter unit than conventional screens. It provides an effect that can reduce the display quality deterioration.

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 (3)

An image display unit including a display liquid crystal layer, a first upper and lower substrates provided at both sides of the display liquid crystal layer, a first polarizing plate provided at one side of the first lower substrate, and a second polarizing plate provided at the other side of the first upper substrate; And an optical shutter unit provided on the other side of the image display unit and having an optical shutter liquid crystal layer interposed between the second upper substrate and the second lower substrate and the second upper substrate and the second lower substrate. In the liquid crystal display device, The second upper substrate and the second lower substrate, respectively, the ITO electrode is provided on the entire surface facing each other, the third polarizing plate is provided on the ITO electrode provided on the second upper substrate in the form of a slit. Display. The method of claim 1, The liquid crystal molecules of the optical shutter liquid crystal layer are positive liquid crystal molecules, The optical axis of the second polarizing plate is perpendicular to the optical axis of the third polarizing plate provided on the ITO electrode. The method of claim 1, The liquid crystal molecules of the optical shutter liquid crystal layer are negative liquid crystal molecules, The optical axis of the second polarizing plate is parallel to the optical axis of the third polarizing plate provided on the ITO electrode surface.

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