KR101654763B1 - Liquid crystal display panel and liquid crystal display device having the same - Google Patents

Abstract

A liquid crystal panel and a liquid crystal display device having the same are disclosed.

A liquid crystal panel and a liquid crystal display device having the same according to the present invention include first and second transparent electrodes on a lower substrate of a liquid crystal panel including pixels composed of three R, G, and B subpixels and one ECB mode subpixel And a third transparent electrode is formed on the upper substrate of the liquid crystal panel so that the horizontal electric field and the vertical electric field are both formed in the ECB mode subpixel to improve the aperture ratio to secure a wide viewing angle.

A wide viewing angle, a horizontal electric field, a vertical electric field, an ECB mode,

Description

[0001] The present invention relates to a liquid crystal panel and a liquid crystal display device having the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal panel, and more particularly, to a liquid crystal panel capable of securing a wide viewing angle by improving an aperture ratio and a liquid crystal display device having the same.

2. Description of the Related Art In recent years, various portable electronic devices such as a mobile phone, a PDA, and a notebook computer have been developed, and accordingly, a demand for a lightweight, thin flat panel display device is increasing. As such flat panel display devices, a liquid crystal display device (LCD), a plasma display panel (PDP), a field emission display device (FED) and a vacuum fluorescent display device (VFD) have been actively studied. However, , A liquid crystal display (LCD) is in the spotlight because of its high quality.

Such a liquid crystal display device has various display modes according to the arrangement of liquid crystal molecules. However, TN mode liquid crystal display devices are used because of their advantages such as easy monochrome display, quick response speed, and low driving voltage. In this TN mode liquid crystal display, liquid crystal molecules aligned horizontally with the substrate are oriented substantially perpendicular to the substrate when a voltage is applied. Therefore, there is a problem that the viewing angle is narrowed when the voltage is applied due to the refractive index anisotropy of the liquid crystal molecules. In order to solve such a viewing angle problem, a liquid crystal display device of various modes having a near wide viewing angle characteristic has been proposed. Among them, a liquid crystal display device of a transverse electric field mode (In Plane Switching Mode) is actually applied to mass production.

The IPS mode liquid crystal display improves the viewing angle characteristics by forming a horizontal electric field on a plane when a voltage is applied to orient the liquid crystal molecules in a plane direction. The IPS mode liquid crystal display device has excellent viewing angle characteristics because the initial alignment of the liquid crystal is arranged in parallel with the substrate and the substrate is rotated in an actual parallel direction to the substrate. However, the IPS mode has a problem that the response speed is slow and the aperture ratio is reduced, instead of excellent viewing angle characteristics.

Also, only a wide viewing angle may not be advantageous to the user. For example, in the case of creating a secret document, browsing, performing a job requiring security, or using an ATM device, a narrow viewing angle is required more than a wide viewing angle.

In accordance with this demand, a liquid crystal display device having three RGB sub-pixels driven in an IPS mode and one ECB sub-pixel driven in an ECB mode has been developed. The liquid crystal display device can be used as a display device having a wide viewing angle or a display device having a narrow viewing angle depending on a user's selection.

However, such a liquid crystal display device includes an ECB sub-pixel that always maintains a black state for the viewing angle control for each pixel, so that the entire aperture ratio is reduced by about 25%. In order to compensate the brightness according to the aperture ratio reduced by about 25%, the liquid crystal display device supports a backlight or a polarizing plate by a separate method for improving brightness compensation film and light. In the case of the luminance compensation film, the cost of about 4 $ per liquid crystal panel is expected, so that the manufacturing cost may increase.

In the present invention, three transparent electrodes are formed on a liquid crystal panel having pixels including three RGB subpixels and one ECB subpixel, so that both the horizontal electric field and the vertical electric field are formed in the ECB subpixel, And a liquid crystal display device provided with the liquid crystal panel.

Another object of the present invention is to provide a liquid crystal panel and a liquid crystal display device having the liquid crystal panel capable of securing a wide viewing angle according to the improvement of the aperture ratio.

It is another object of the present invention to provide a liquid crystal panel and a liquid crystal display device having the same that can reduce manufacturing cost by eliminating the need for a luminance compensation film.

A liquid crystal panel according to an embodiment of the present invention includes a unit pixel composed of R, G, and B sub-pixels defined by the intersection of a plurality of gate lines and data lines and sub-pixels for ECB mode, A thin film transistor formed for each subpixel for a pixel and an ECB mode; a common electrode line formed for each of the R, G, B subpixels and the ECB mode subpixel and horizontally aligned with the data line; A first transparent electrode that is formed for each of the subpixels for the pixel and the ECB mode and short-circuits the drain electrode of the thin film transistor; and a second transparent electrode formed for each of the R, G, and B subpixels and the ECB mode subpixel, A third transparent electrode formed on the second substrate facing the first substrate on which the first and second transparent electrodes formed on the sub-pixels for ECB mode are formed; remind A common connection line formed for each of the R, G, and B subpixels and for the ECB mode subpixel and for branching the second transparent electrode; and a second transparent electrode formed in the subpixel for ECB mode, And a liquid crystal layer formed between the first and second substrates.

A liquid crystal display device according to an embodiment of the present invention includes a unit pixel including R, G, and B sub-pixels defined by the intersection of a plurality of gate lines and data lines and sub-pixels for ECB mode, A thin film transistor formed for each subpixel and each subpixel for ECB mode; A common electrode line which is formed for each of the R, G, B sub-pixels and the ECB mode sub-pixel and which is parallel to the data line and is formed for each of the R, G, B sub-pixels and the ECB mode sub- A second transparent electrode formed on each of the R, G, and B sub-pixels and the sub-pixels for the ECB mode and forming a horizontal electric field with the first transparent electrode on the first transparent electrode, A third transparent electrode formed on a second substrate opposite to a first substrate having first and second transparent electrodes formed on the sub-pixel for the ECB mode, and a second transparent electrode formed on the second substrate opposite to the R, G, B sub- And a second connection electrode connected to the first electrode and the second electrode, the common electrode being connected to the storage electrode, And a liquid crystal layer formed between the first substrate and the second substrate, a gate driver for supplying a scan signal to the gate line of the liquid crystal panel, a data driver for supplying a data signal to the data line of the liquid crystal panel, Pixels for supplying the common voltage to the second and third transparent electrodes formed in the ECB mode subpixel of the liquid crystal panel and supplying common voltages to the second and third transparent electrodes formed in the R, And a voltage generating unit.

In the present invention, three transparent electrodes are formed on a liquid crystal panel having pixels including three RGB subpixels and one ECB subpixel, so that both the horizontal electric field and the vertical electric field are formed in the ECB subpixel, It is possible to secure a wide viewing angle.

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

1 is a plan view of a first substrate of a liquid crystal panel according to an embodiment of the present invention.

1, a plurality of gate lines GL and a plurality of data lines DL intersecting the gate lines GL are formed on a first substrate of a liquid crystal panel according to an exemplary embodiment of the present invention, A plurality of unit pixels defined by the plurality of gate lines GL and data lines DL are formed. At this time, the unit pixel includes four sub-pixels. The four sub-pixels include R, G, and B sub-pixels and sub-pixels for an ECB (Electrically Controlled Birefringence) mode.

A gate electrode 101 extending from the gate line GL and a source electrode 103 extending from the data line DL are formed in the four subpixels and a source electrode 103 extending from the source electrode 103, Drain electrodes 107 are formed. On the gate electrode 101, an active layer (not shown) is formed. The gate electrode 101, the active layer, and the source and drain electrodes 103 and 107 form a thin film transistor (TFT).

In the R, G, and B sub-pixels, a 1-1 first transparent electrode 110a having a large area and short-circuiting with the drain electrode 107, The common connection line 120a and at least two or more second-1 transparent electrodes 120b branching from the common connection line 120a are formed. In addition, a common electrode line (VL) horizontal to the data line (DL) is formed in the R, G, and B sub-pixels. Here, the first and second transparent electrodes 110a and 120b and the first common connection line 120a may be formed of a transparent conductive material such as ITO (Indium Tin Oxide).
In the sub-pixel for the ECB mode, the first and second transparent electrodes 110b and 110b, which are short-circuited with the drain electrode 107 and have a large area, and a second common connection line Line 120c and at least two or more second 2-2 transparent electrodes 120d branching from the second common connection line 120c are formed. In addition, a common electrode line (VL) horizontal to the data line (DL) is formed in the sub-pixel for the ECB mode. At this time, the first and second transparent electrodes 110b and 120d and the second common connection line 120c may be formed of a transparent conductive material such as ITO (Indium Tin Oxide).

The first 1-1 transparent electrode 110a and the 1-2 transparent electrode 110b are used as a pixel electrode and the 2-1 transparent electrode 120b is used as a first common electrode, And the electrode 120d is used as the second common electrode.

In the sub-pixel for the ECB mode among the four sub-pixels, a storage electrode 102 formed of the same process and material as the gate line GL is formed. The storage electrode 102 is formed in the sub- 1-2 the transparent electrode 110b. In addition, the first and second contact holes H1 and H2 are formed in the sub-pixel for the ECB mode.

The first contact hole H1 allows the common electrode line VL formed in the sub-pixel for the ECB mode and the second and second transparent electrodes 120d formed in the sub-pixel for the ECB mode to be electrically connected to each other. The second contact hole H2 may be formed by connecting the storage electrode 102 formed in the sub-pixel for the ECB mode to the first common connection line 120a or the second common connection line 120a formed in any one of sub- -1 < / RTI > transparent electrode 120b.

FIG. 2 is a plan view showing a second substrate bonded to a first substrate of the liquid crystal panel of FIG. 1. FIG.

As shown in FIGS. 1 and 2, a third transparent electrode 130 is formed on the entire surface of the sub-pixel for the ECB mode among the four sub-pixels. The third transparent electrode 130 is electrically connected to a transparent electrode connection line 135 overlapping the gate line GL of one of sub-pixels of adjacent R, G, and B sub-pixels. The transparent electrode connection line 135 is electrically connected to the third transparent electrodes 130 formed on the sub-pixels for the ECB mode formed for each unit pixel, and is connected to the common voltage generating unit (Vcom) to the third transparent electrode (130). The third transparent electrode 130 is used as a third common electrode.

The third transparent electrode 130 and the transparent electrode connection line 135 may be formed of indium tin oxide (ITO) as in the second common connection line 120c and the first and second transparent electrodes 110b and 120d. Oxide) or the like.

FIG. 3 is a cross-sectional view of the R subpixel of FIG. 1 taken along lines I-I '.

1 and 3, the R sub-pixel includes a gate insulating layer 104 formed on a first glass substrate 100, a data line DL formed at both ends of the gate insulating layer 104, A first transparent electrode 110a formed on a region where the data line DL and the common electrode line VL are not formed on the gate insulating layer 104, A protective layer 108 formed to protect the line DL and the common electrode line VL and the first transparent electrode 110a and a protective layer 108 formed on the protective layer 108 to protect the first transparent electrode 110a, And a second transparent electrode 120b overlapped with the second transparent electrode 120b.

As described above, since the first transparent electrode 110a is in a state of being short-circuited with the drain electrode 107 of the TFT of FIG. 1, the data signal supplied from the data line DL May be provided as the 1-1th transparent electrode 110a and used as a pixel electrode. A common voltage may be applied to the 2-1th transparent electrode 120b so that the 2-1th transparent electrode 120b may be used as a first common electrode. At this time, the first transparent electrode 110a has a larger area than the second transparent electrode 120b.

4 is a cross-sectional view of the sub-pixel for the ECB mode of FIG. 1 taken along II-II '.

1 and 4, the sub-pixel for the ECB mode includes a storage electrode 102 formed on the first glass substrate 100 and formed of the same process and material as the gate line GL of FIG. 1, A gate insulating layer 104 formed on the electrode 102 and a data line DL formed on both ends of the gate insulating layer 104 and not overlapping the storage electrode 102, A first transparent electrode 110b formed on the gate insulating layer 104 in a region where the data line DL and the common electrode line VL are not formed; A protective layer 108 formed on the protective layer 108 to protect the first and second transparent electrodes 110a and 110b and the common electrode line VL and the first and second transparent electrodes 110b, -2 transparent electrode 120d.

The storage electrode 102 may include a first common connection line 120a or a second transparent electrode 120b included in one of the R, G, and B subpixels adjacent to the subpixel for the ECB mode, And is electrically connected. Therefore, a common voltage is supplied to the first common connection line 120a or the second-1 transparent electrode 120b included in any one of the R, G, and B sub-pixels adjacent to the sub-pixel for the ECB mode The storage electrode 102 is provided with a common voltage.

Since the first and second transparent electrodes 110b are in a shorted state with the drain electrode 107 of the thin film transistor TFT of FIG. 1, the data signal supplied from the data line DL is supplied to the first- Lt; RTI ID = 0.0 > 110b < / RTI > A common voltage may be applied to the second-second transparent electrode 120d, and the second-second transparent electrode 120d may be used as a second common electrode. At this time, the first-second transparent electrode 110b has a larger area than the second-1 transparent electrode 120d.

5 is a cross-sectional view of the R subpixel of FIG. 2 cut along III-III '.

2 and 5, the R sub-pixel includes a gate insulating layer 104 formed on the first glass substrate 100, a data line DL formed at both ends of the gate insulating layer 104, A first transparent electrode 110a formed on a region where the data line DL and the common electrode line VL are not formed on the gate insulating layer 104, A protective layer 108 formed to protect the line DL and the common electrode line VL and the first transparent electrode 110a and a protective layer 108 formed on the protective layer 108 to protect the first transparent electrode 110a, And a second transparent electrode 120b overlapped with the second transparent electrode 120b.

The R subpixel includes a black matrix 124 formed on the second glass substrate 122 to correspond to the data line DL and the common electrode line VL of the first glass substrate 100, A red color filter 126 having red (R) color formed on a black matrix 124 and a planarization layer 128 formed on the red color filter 126. In addition, the R sub-pixel includes a liquid crystal layer (not shown) formed between the first and second glass substrates 100 and 122.

When the liquid crystal layer is driven, a data signal is provided to the 1-1 transparent electrode 110a, and a common voltage is applied to the 2-1 transparent electrode 120b so that the 1-1 transparent electrode 110a, A horizontal electric field is generated between the first transparent electrode 120a and the second transparent electrode 120b. That is, when the liquid crystal layer included in the R sub-pixel is driven, a horizontal electric field is generated in the R sub-pixel.

FIG. 6 is a cross-sectional view of the sub-pixel for ECB mode of FIG. 2 taken along line IV-IV '.

As shown in FIGS. 2 and 6, the sub-pixel for the ECB mode includes a storage electrode 102 formed on the first glass substrate 100 and formed of the same process and material as the gate line GL of FIG. 1, A gate insulating layer 104 formed on the electrode 102 and a data line DL formed on both ends of the gate insulating layer 104 and not overlapping the storage electrode 102, A first transparent electrode 110b formed on the gate insulating layer 104 in a region where the data line DL and the common electrode line VL are not formed; A protective layer 108 formed on the protective layer 108 to protect the first and second transparent electrodes 110a and 110b and the common electrode line VL and the first and second transparent electrodes 110b, -2 transparent electrode 120d.

The ECB mode subpixel includes a black matrix 124 formed on the second glass substrate 122 to correspond to the data line DL and the common electrode line VL of the first glass substrate 100, A planarization layer 128 formed on the entire surface of the second glass substrate 122 on which the black matrix 124 is formed and a third transparent electrode 130 formed on the planarization layer 128. In addition, the sub-pixel for the ECB mode includes a liquid crystal layer (not shown) formed between the first and second glass substrates 100 and 122.

The liquid crystal of the liquid crystal layer formed in the sub-pixel for the ECB mode is aligned in the same manner as the liquid crystal of the liquid crystal layer formed in the R sub-pixel of Fig.

In order to form a horizontal electric field (1) on the sub-pixels for the ECB mode, a data signal is provided to the first and second transparent electrodes 110b and a common voltage is provided to the second and second transparent electrodes 120d. At this time, the third transparent electrode 130 formed on the second glass substrate 122 maintains a floating state. That is, no common voltage is supplied to the third transparent electrode 130.

When the horizontal electric field (1) is formed in the sub-pixel for the ECB mode, only the 1-1, 1-2, 2-1 and 2-2 transparent electrodes 110a, 110b, 120b, And is involved in the operation of the liquid crystal layer. Since the horizontal electric field (1) is formed in the sub-pixel for the ECB mode, the liquid crystal formed in the sub-pixel for the ECB mode is driven like the liquid crystal formed in the R, G, and B sub-pixels of FIG. Since the sub-pixels for the ECB mode are driven in the same manner as the R, G, and B sub-pixels, the sub-pixels for the ECB mode transmit white light because no color filter exists.

The white light may be adjusted according to the gamma curve of the data displayed on the R, G, and B sub-pixels.

Since the horizontal electric field (1) is formed in the sub-pixel for the ECB mode and white light is transmitted, the aperture ratio of the unit pixel including the sub-pixel for the ECB mode can be improved.

In order to form a vertical electric field (2) on the sub-pixels for the ECB mode, a data signal is provided to the first and second transparent electrodes 110b and a common voltage is provided to the third transparent electrodes 130. [ At this time, the second and second transparent electrodes 120d formed on the first glass substrate 100 maintain a floating state. That is, the common voltage is not supplied to the (2-2) transparent electrode 120d.

As a result, when the vertical electric field (2) is formed in the sub-pixel for the ECB mode, only the first and second transparent electrodes 110b and 130 are involved in the operation of the liquid crystal layer formed in the sub-pixel for the ECB mode . Since the vertical electric field (2) is formed in the sub-pixel for the ECB mode, the ECB mode sub-pixel maintains the black state. When the vertical electric field (2) is formed in the sub-pixel for the ECB mode, the liquid crystal contained in the sub-pixel for the ECB mode is vertically erected so that the angle at which the image can be viewed is narrowed do. When a narrow viewing angle is required, the sub-pixels for the ECB mode are driven to form a vertical electric field (2).

As described above, the sub-pixel for the ECB mode can be applied to a liquid crystal display device having a wide viewing angle or a narrow viewing angle by forming a horizontal electric field (1) and a vertical electric field (2) according to the selection of an external user.

Since the horizontal electric field (1) is formed in the sub-pixel for the ECB mode and white light is emitted, the luminance of the unit pixel having the sub-pixel for the ECB mode is improved and a separate luminance compensation film is required unlike the conventional liquid crystal display . Since the luminance compensation film is not required, the manufacturing cost of the liquid crystal display device according to the present invention can be reduced.

1 is a plan view of a first substrate of a liquid crystal panel according to an embodiment of the present invention;

FIG. 2 is a plan view showing a second substrate bonded to a first substrate of the liquid crystal panel of FIG. 1;

3 is a cross-sectional view of the R subpixel of FIG. 1 taken along lines I-I ';

FIG. 4 is a cross-sectional view of the sub-pixel for ECB mode in FIG. 1 taken along II-II ';

5 is a cross-sectional view of the R subpixel of FIG. 2 cut along III-III ';

6 is a cross-sectional view of the sub-pixel for ECB mode of FIG. 2 taken along IV-IV ';

Claims (10)

A unit pixel composed of R, G, and B subpixels defined by intersections of a plurality of gate lines and data lines and subpixels for ECB mode; A thin film transistor of each of the R, G, and B sub-pixels and the sub-pixel of the ECB mode; A common electrode line horizontally aligned with the data lines on the R, G, B sub-pixels and sub-pixels for ECB mode; A first 1-1 transparent electrode that is short-circuited with a drain electrode of the thin film transistor on the R, G, and B sub-pixels; A second transparent electrode that is short-circuited with the drain electrode of the thin film transistor on the sub-pixel for the ECB mode; A first common connection line horizontal to the gate line and on the R, G, B subpixels; A 2-1 transparent electrode on the R, G, and B subpixels branched from the first common connection line and forming a horizontal electric field with the 1-1 transparent electrode on the 1-1 transparent electrode; A second common connection line horizontal to the gate line and on the sub-pixel for the ECB mode; A second-2 transparent electrode on the sub-pixel for ECB mode, which branches from the second common connection line and forms a horizontal electric field on the first transparent electrode and the second transparent electrode; A third transparent electrode on a second substrate opposite to the first substrate on which the 1-2 and 2-2 transparent electrodes are arranged on the sub-pixels for the ECB mode; A storage electrode disposed in the sub-pixel for the ECB mode and surrounding the edge of the first and second transparent electrodes on the sub-pixel for the ECB mode; And And a liquid crystal layer between the first and second substrates, The ECB mode subpixel includes a first contact hole for electrically connecting a common electrode line on the sub-pixel for ECB mode and a 2-2 transparent electrode on the sub-pixel for the ECB mode, And a second contact hole for electrically connecting the first common connection line on any one of the G, B sub-pixels. delete The method according to claim 1, The second contact hole connects the second-1 transparent electrode on any one of the subpixels of the R, G, and B sub-pixels to the storage electrode, and while the common voltage is applied to the second-1 transparent electrode, And the common voltage is applied to the electrodes. The method according to claim 1, Wherein a data signal is provided to a 1-2 th transparent electrode on the sub-pixel for ECB mode and a common voltage is provided to a 2-2 th transparent electrode on the sub-pixel for the ECB mode. 5. The method of claim 4, And the third transparent electrode is in a floating state when a common voltage is provided to the second-2 transparent electrode. The method according to claim 1, A data signal is provided to the first to second transparent electrodes on the sub-pixels for the ECB mode, and a common voltage is provided to the third transparent electrodes on the sub-pixels for the ECB mode. The method according to claim 6, And the second-2 transparent electrode formed in the sub-pixel for ECB mode is in a floating state when a common voltage is provided to the third transparent electrode. A unit pixel composed of R, G, B sub-pixels and sub-pixels for ECB mode defined by the intersection of a plurality of gate lines and data lines, and a thin film of each of the R, G, B sub- A first common electrode line on the R, G, and B sub-pixels, a common electrode line on the sub-pixel for the ECB mode and a horizontal common electrode line on the data line, And a first common connection line which is horizontal to the gate line and overlaps with the first common connection line on the R, G, and B sub-pixels, A second-1 transparent electrode on the R, G, and B subpixels branched from the first common connection line and forming a horizontal electric field with the first transparent electrode on the first transparent electrode, Horizontal to line A second common connection line on the sub-pixel for the ECB mode, and a second common connection line on the sub-pixel for the ECB mode, the second common connection line on the second common connection line, A third transparent electrode on a second substrate opposite to the first substrate on which the 1-2 and 2-2 transparent electrodes are arranged on the sub-pixels for the ECB mode; And a liquid crystal layer disposed between the first and second substrates, and a storage electrode disposed in the sub-pixel for the ECB mode and surrounding the edge of the first and second transparent electrodes on the sub-pixel for the ECB mode. A gate driver for supplying a scan signal to a gate line of the liquid crystal panel; A data driver for supplying a data signal to a data line of the liquid crystal panel; And A common voltage is supplied to the 2-1th transparent electrodes on the subpixels for the R, G, and B modes of the liquid crystal panel, and a common voltage is selectively applied to the 2-2nd and third transparent electrodes on the ECB mode subpixel of the liquid crystal panel And a common voltage generator for supplying a voltage, The ECB mode subpixel includes a first contact hole for electrically connecting a common electrode line on the sub-pixel for ECB mode and a 2-2 transparent electrode on the sub-pixel for the ECB mode, And a second contact hole for electrically connecting the first common connection line on any one of the G, B sub-pixels. delete 9. The method of claim 8, The second contact hole connects the second-1 transparent electrode on any one of the subpixels of the R, G, and B sub-pixels to the storage electrode, and while the common voltage is applied to the second-1 transparent electrode, And the common voltage is applied to the electrodes.

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