LCD Display

Abstract

A liquid crystal display is provided. The liquid crystal display comprises: a liquid crystal panel including a liquid crystal layer, a pixel electrode and a common electrode; and a backlight unit including a light source to provide light to the liquid crystal panel. The pixel electrode comprises: a longitudinal electrode having a strip shape and extending in a vertical direction; a transverse electrode having a strip shape, crossing the longitudinal electrode and extending in a horizontal direction; and a branch electrode having a strip shape, extending from the longitudinal electrode or the transverse electrode, and including an inclined portion extending in an inclined direction. The common electrode is overlapped with the longitudinal electrode, a longitudinal opening extending in the vertical direction is defined in the common electrode, and the width of a portion of the pixel electrode where the longitudinal electrode and the transverse electrode cross each other is substantially the same as the width of the transverse electrode.

Description

[0001] This application claims priority to and all benefits arising from Korean Patent Application No. 10-2018-0108355, filed on September 11, 2018, the contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] The present disclosure relates to a liquid crystal display, and in particular, to a high-resolution liquid crystal display with high transmittance. Background Art

[0003] The liquid crystal display may include two field generating electrodes, a liquid crystal layer, a color filter, and a polarizing layer. The light generated from the light source reaches the viewer after passing through the liquid crystal layer, the color filter, and the polarizing layer, and the polarization characteristics of the light change according to the arrangement angle of the liquid crystal layer. As a result, the gray level of the image displayed by the light from the light source is controlled while the light is partially blocked by the polarizing layer. Summary of the invention

[0004] As the resolution of a display device becomes higher, the size of a pixel becomes smaller, so that transmittance is reduced when the display device displays in a conventional method.

[0005] Exemplary embodiments relate to a liquid crystal display having high transmittance.

[0006] An exemplary embodiment of a liquid crystal display includes: a liquid crystal panel including a liquid crystal layer, a pixel electrode and a common electrode; and a backlight unit including a light source, wherein the backlight unit provides light to the liquid crystal panel. In such an embodiment, the pixel electrode includes: a longitudinal electrode having a strip shape and extending in a vertical direction; a transverse electrode having a strip shape, crossing the longitudinal electrode, and extending in a horizontal direction; and a branch electrode having a strip shape, extending from the longitudinal electrode and the transverse electrode, and including an inclined portion extending in an inclined direction relative to the longitudinal electrode or the transverse electrode. In such an embodiment, the common electrode has a longitudinal opening overlapping the longitudinal electrode of the pixel electrode and extending in the vertical direction, and the width of the portion of the pixel electrode where the longitudinal electrode and the transverse electrode cross each other is substantially the same as the width of the transverse electrode or the width of the longitudinal electrode.

[0007] In an exemplary embodiment, the pixel electrode may further include an edge transverse electrode having a stripe shape, extending in a horizontal direction, and connected to an end portion of the longitudinal electrode.

[0008] In exemplary embodiments, the edge lateral electrodes may be connected to ends of the branch electrodes.

[0009] In an exemplary embodiment, the inclined portion of the branch electrode may form an angle ranging from about 60 degrees to about 80 degrees with the transverse electrode.

[0010] In an exemplary embodiment, the common electrode may further include a cutout opening having a width extending at the longitudinal opening.

[0011] In an exemplary embodiment, the cutout opening may overlap a portion where the longitudinal electrodes and the transverse electrodes cross each other.

[0012] In an exemplary embodiment, the pixel electrode may further include an edge longitudinal electrode having a stripe shape, connected to an end of the transverse electrode, and parallel to the longitudinal electrode.

[0013] In an exemplary embodiment, the pixel electrode may further include an edge longitudinal electrode having a stripe shape and parallel to the longitudinal electrode, and the edge longitudinal electrode may be connected to ends of the branch electrodes and may not be connected to the transverse electrode.

[0014] In an exemplary embodiment, the branch electrode may further include a portion parallel to the transverse electrode or the longitudinal electrode, thereby defining a bent structure with the inclined portion.

[0015] In an exemplary embodiment, the common electrode may further include a cutout opening having a width extending at the longitudinal opening, and the cutout opening may overlap a portion where the longitudinal electrode and the transverse electrode cross each other.

[0016] In an exemplary embodiment, the cutout opening may extend parallel to the lateral electrodes.

[0017] In an exemplary embodiment, the pixel electrode may include a first pixel electrode and a second pixel electrode adjacent to each other, and the liquid crystal panel may also include a first gate line, a second gate line, a first data line, a second data line, a first thin film transistor and a second thin film transistor, the first thin film transistor may be connected to the first pixel electrode and connected to the first gate line and the first data line, and the second thin film transistor may be connected to the second pixel electrode and connected to the second gate line and the second data line.

[0018] In an exemplary embodiment, the first gate line and the second gate line may receive the same gate signal as each other.

[0019] In an exemplary embodiment, the first pixel electrode and the second pixel electrode may be arranged along an extension direction of the first data line and the second data line, and the first data line and the second data line may be disposed to cross the first pixel electrode and the second pixel electrode, respectively.

[0020] In an exemplary embodiment, the liquid crystal panel may further include an upper polarizer and a lower polarizer respectively attached at both sides thereof.

[0021] In an exemplary embodiment, the backlight unit may further include a prism sheet disposed under the liquid crystal panel and a reflective sheet disposed under the prism sheet, the prism sheet may have a prism mountain, and the prism mountain may be disposed toward the reflective sheet.

[0022] In an exemplary embodiment, the extending direction of the prism mountain-shaped member may be the same as the short side direction of the liquid crystal panel, and the prism mountain-shaped member extending in the long side direction of the liquid crystal panel may not be included.

[0023] In an exemplary embodiment, the backlight unit may further include a light guide between the prism sheet and the reflective sheet, and the light source may be disposed at one side of the light guide.

[0024] In an exemplary embodiment, the liquid crystal panel may further include a diffuser attached to an upper surface of the upper polarizer.

[0025] In an exemplary embodiment, the diffuser may diffuse light incident thereto in a short side direction of the liquid crystal panel.

[0026] According to an exemplary embodiment, even if the size of a pixel is reduced as a liquid crystal display with high resolution is provided, the arrangement direction of the liquid crystal molecules is arranged to have high transmittance, thereby obtaining high transmittance. In such an embodiment, the characteristic degradation from the side viewing angle due to the arrangement characteristics of the liquid crystal molecules is effectively compensated by using a reversely arranged prism sheet that transmits light in the left and right directions.

[0027] In such an embodiment, the writing time of the data voltage is effectively ensured under high resolution. In such an embodiment, two data lines can be set for one pixel column so that the pixels of two rows can be turned on at the same timing. In such an embodiment, the two data lines can be set to cross the pixels so that the area covered by the black matrix is ​​reduced, thereby improving the transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The above and other features of the invention will become more apparent by describing in more detail exemplary embodiments of the invention with reference to the accompanying drawings, in which:

[0029] Figure 1 is a schematic diagram showing a connection relationship of pixel electrodes in a liquid crystal display according to an exemplary embodiment;

[0030] Figure 2 is a cross-sectional view showing an entire structure of a liquid crystal display according to an exemplary embodiment;

[0031] Figure 3 is a top view showing the structure of a pixel electrode and a common electrode in a pixel according to an exemplary embodiment;

[0032] Figure 4 It shows that according to Figure 3 A diagram showing the arrangement of liquid crystal molecules in an electrode structure;

[0033] Figure 5is a diagram showing an arrangement of liquid crystal molecules according to an angle of a branch electrode in a pixel electrode according to an exemplary embodiment;

[0034] Figure 6 is a graph showing angular transmittance according to branch electrodes in a pixel electrode according to an exemplary embodiment;

[0035] Figure 7 is a diagram of a structure of a pixel electrode, an arrangement of liquid crystal molecules, and transmittance according to an exemplary embodiment;

[0036] Figure 8 is a graph showing transmittance according to a comparative example and an exemplary embodiment;

[0037] Fig. 9 is a diagram showing the arrangement of liquid crystal molecules according to a comparative example and an exemplary embodiment;

[0038] Fig.10 is a diagram showing a change in characteristics according to a change in a cutout in a common electrode according to an exemplary embodiment;

[0039] Fig.11 is a graph showing changes in brightness in the front and side surfaces according to a comparative example and an exemplary embodiment;

[0040] Fig.12 is a diagram showing alignment characteristics of liquid crystal molecules according to voltage at a specific position in a comparative example and an exemplary embodiment;

[0041] Fig.13 is a diagram showing angles based on positions of liquid crystal molecules according to voltage in a comparative example and an exemplary embodiment;

[0042] Fig.14 is a diagram showing structures of a pixel electrode and a common electrode according to various exemplary embodiments;

[0043] Fig.15 is a diagram showing a structure of a common electrode according to various exemplary embodiments;

[0044] Fig.16 is a diagram showing light leakage in an upper side of an arrangement for liquid crystal molecules according to an exemplary embodiment;

[0045] Fig.17 is a diagram showing characteristics according to positions for arrangement of liquid crystal molecules according to an exemplary embodiment;

[0046] Fig.18 is a diagram showing characteristics of light provided from a backlight unit of a liquid crystal display according to an exemplary embodiment;

[0047] Fig.19is a graph showing characteristics of a prism sheet according to a comparative example and characteristics of a prism sheet according to an exemplary embodiment;

[0048] Fig. 20 is a graph showing characteristics changed by using a prism sheet according to an exemplary embodiment; and

[0049] Fig.21 is a graph showing characteristics of light for each position of a liquid crystal display according to an exemplary embodiment. DETAILED DESCRIPTION

[0050] The invention will be described more fully hereinafter with reference to the accompanying drawings in which exemplary embodiments of the invention are shown. However, the invention may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. The same reference numerals represent the same elements throughout.

[0051] In addition, in the drawings, for better understanding and ease of description, the size and thickness of each element are arbitrarily shown, and the invention is not limited thereto. In the drawings, for clarity, the thickness of layers, films, panels, regions, etc. are exaggerated. In the drawings, for ease of description, the thickness of layers, films, panels, regions, etc. are exaggerated.

[0052] It will be understood that when an element such as a layer, film, region, or substrate is referred to as being "on" another element, the element may be directly on the other element, or intervening elements may also be present. In contrast, when an element is referred to as being "directly on" another element, there are no intervening elements. In addition, in the specification, the words "on..." or "above..." mean disposed on or below an object part, and do not necessarily mean disposed on the upper side of the object part based on the direction of gravity.

[0053] It will be understood that, although the terms "first", "second", "third", etc. can be used herein to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings herein, the "first element", "first component", "first region", "first layer" or "first part" discussed below can be named as the second element, second component, second region, second layer or second part.

[0054] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limiting. As used herein, unless the context clearly indicates otherwise, the singular forms "one", "one (kind, person)" and "the (the)" are also intended to include plural forms including "at least one (kind, person) in..." "Or" means "and / or". "At least one (kind, person) in A and B" means "A and / or B". As used herein, the term "and / or" includes any combination and all combinations of one or more related listed items. It will also be understood that when the terms "include", "comprising" and variations thereof are used in this specification, it is explained that there are stated features, regions, wholes, steps, operations, elements and / or components, but it is not excluded that there are or add one or more other features, regions, wholes, steps, operations, elements, components and / or their groups.

[0055] The phrase "in plane" means viewing an object part from the top, and the phrase "in section" means viewing a vertically cut section of the object part from the side.

[0056] For ease of description, spatially relative terms such as "under," "below," "below," "above," "above," etc. may be used herein to describe the relationship of one element or feature to another element or feature as shown in the accompanying drawings. It will be understood that, in addition to the orientation depicted in the accompanying drawings, the spatially relative terms are intended to encompass different orientations of the device in use or operation. For example, if the device in the accompanying drawings is flipped, an element described as "under" or "below" other elements or features will subsequently be positioned as "above" the other elements or features. Thus, the exemplary term "under" may encompass both above and below orientations. The device may be otherwise positioned (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein interpreted accordingly.

[0057] As used herein, "about" or "approximately" is inclusive of the stated value and means: within an acceptable range of deviation for the particular value as determined by one of ordinary skill in the art, taking into account the measurements being discussed and the errors associated with the measurement of the particular quantity (i.e., the limitations of the measurement system).

[0058] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as those commonly understood by those of ordinary skill in the art to which the present disclosure belongs. It will also be understood that, unless expressly defined as such herein, terms (such as those defined in common dictionaries) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and the present disclosure, and will not be interpreted in an idealized or overly formal sense.

[0059] Exemplary embodiments are described herein with reference to cross-sectional views as schematic diagrams of ideal embodiments. As such, variations in the shapes of the diagrams, such as those caused by manufacturing techniques and / or tolerances, are expected to occur. Therefore, the embodiments described herein should not be construed as being limited to the specific shapes of the regions shown herein, but will include deviations in shape, such as those caused by manufacturing. For example, a region shown or described as flat may typically have rough and / or nonlinear features. In addition, the sharp corners shown may be rounded. Therefore, the regions shown in the accompanying drawings are schematic in nature, and their shapes are not intended to illustrate the precise shape of the regions and are not intended to limit the scope of the claims.

[0060] Hereinafter, exemplary embodiments of the invention will be described in detail with reference to the accompanying drawings.

[0061] Figure 1 is a schematic diagram illustrating a connection relationship of pixel electrodes in a liquid crystal display according to an exemplary embodiment.

[0062] Will refer to Figure 1 The pixel electrode 190, the gate line G in the lower panel of the liquid crystal display according to the exemplary embodiment are described in detail. i , G (i-1) and G (i-2) , data line D j , D' j , D (j+1) and D' (j+1) And the relationship between thin film transistor TFT.

[0063] In an exemplary embodiment, the lower panel of the liquid crystal display has one gate line G i Divided into two gate lines G (i-1) and G (i-2) In this embodiment, two data lines (a pair of data lines) are arranged in a column of pixel electrodes 190. In an exemplary embodiment, as shown in FIG. Figure 1 As shown in FIG. 1 , two data lines D j and D' j The other two data lines D are arranged to extend vertically and intersect with the pixel electrodes 190 in the first column (eg, the left column) of the plurality of pixel electrodes 190. (j+1) and D' (j+1) The data lines are arranged to extend vertically and intersect with the pixel electrodes 190 in the second column (e.g., right column) of the plurality of pixel electrodes 190. Here, when viewed from a plan view in the thickness direction of the lower panel of the liquid crystal display, the vertical direction may be an extending direction of the data lines, and the horizontal direction may be a direction perpendicular to the vertical direction.

[0064] Two thin film transistors TFT connected to the pixel electrodes 190 included in one column and vertically adjacent to each other are connected to gate lines G1 different from each other. (i-1) and G (i-2) and different data lines D j , D' j , D (j+1) and D' (j+1) In such an embodiment, the gate lines G (i-1) and G (i-2) The data lines D may be connected to each other, that is, their ends are connected to one gate line Gi so that the same gate-on voltage is applied to them at the same time. j , D' j , D (j+1) and D' (j+1) The two thin film transistors TFT that are vertically adjacent to each other are not connected to each other so that data voltages different from each other may be applied.

[0065] Will refer to Figure 1 The four adjacent pixel electrodes 190, the thin film transistor TFT, the gate line G (i-1) and G (i-2) And data cable D j , D' j , D (j+1) and D' (j+1) connection relationship.

[0066] Figure 1 There are shown four vertically and horizontally adjacent pixel electrodes 190. Each pixel electrode 190 is connected to a corresponding thin film transistor TFT (ie, an output terminal thereof).

[0067] Connected to the gate line G (i-1) and G (i-2) Among the thin film transistors TFT, the thin film transistors TFT arranged in the same row are connected to the same gate line, and the thin film transistors TFT arranged in different rows are connected to different gate lines. (i-1) and G (i-2) Each of the gate lines G is disposed between the pixel electrodes 190. (i-1) and G (i-2) The side ends are merged into a single gate line G i , thereby receiving the same gate signal. When gate lines receiving the same gate signal are referred to as one gate line, the number of gate lines may be half the number of rows of pixel electrodes 190. On the other hand, the number of all gate lines extending horizontally is the same as the number of rows of pixel electrodes 190.

[0068] The input terminal of the thin film transistor TFT is connected to the data line Dj , D' j , D (j+1) and D' (j+1) , thin film transistors TFT vertically adjacent to each other may be connected to different data lines. In an exemplary embodiment, when the gate signals applied to the thin film transistors TFT are the same as each other, the thin film transistors TFT are respectively connected to different data lines. In an exemplary embodiment, as Figure 1 As shown in FIG. 1 , the thin film transistor TFT disposed at the upper left side is connected to a pair of data lines D j and D' j The data line D disposed on the left side j , the thin film transistor TFT disposed at the lower left side is connected to the data line D' disposed at the right side j In an exemplary embodiment, as Figure 1 As shown in FIG. 1 , the thin film transistor TFT disposed at the upper right side is connected to the data line D disposed at the left side. (j+1) , the thin film transistor TFT disposed at the lower right side is connected to the data line D' disposed at the right side (j+1) In an alternative exemplary embodiment, the thin film transistor TFT disposed at the upper right side may be connected to the data line D' disposed at the right side. (j+1) , the thin film transistor TFT disposed at the lower right side may be connected to the data line D disposed at the left side (j+1) .

[0069] In an exemplary embodiment, a pair of data lines are disposed to extend vertically along the pixel electrode 190. In such an embodiment, if the pixel electrode 190 is divided into a left region and a right region based on the center of the pixel electrode 190, the pair of data lines may be disposed at the left region and the right region of the pixel electrode 190, respectively. In such an embodiment, the data line may be disposed while crossing the exact center of the left region or the right region. In an exemplary embodiment, as described above, the data line D j , D' j , D (j+1) and D' (j+1) Overlapping the pixel electrode 190 makes it possible to reduce the interval between the pixel electrodes 190 adjacent to each other in the horizontal direction, thereby reducing the area covered by the black matrix BM. As a result, in such an embodiment, transmittance is improved.

[0070] In an exemplary embodiment, the thin film transistor TFT in the display panel, the gate line G and the gate line G can be connected as described above. i , G (i-1) and G (i-2) And data cable D j , D' j , D(j+1) and D' (j+1) .

[0071] Figure 1 Such a structure may be provided in a lower panel among liquid crystal panels constituting a liquid crystal display. The liquid crystal panel includes a lower panel and an upper panel and a liquid crystal layer disposed between the lower panel and the upper panel. In an exemplary embodiment, the liquid crystal display further includes a backlight unit.

[0072] Will refer to Figure 2 To describe the structure of a liquid crystal display.

[0073] Figure 2 is a cross-sectional view illustrating an entire structure of a liquid crystal display according to an exemplary embodiment.

[0074] In an exemplary embodiment, if Figure 2 As shown in FIG. 1 , the liquid crystal display includes a liquid crystal panel ( 100 , 310 , 320 , and 330 ) and a backlight unit ( 400 , 410 , 420 , and 430 ).

[0075] The liquid crystal panel includes a display panel 100 , a lower polarizer 310 , an upper polarizer 320 , and a diffusion layer 330 .

[0076] In an exemplary embodiment, although Figure 2 Although not shown in the figure, the display panel 100 includes an upper panel and a lower panel and a liquid crystal layer disposed between the upper panel and the lower panel. Figure 1 As described, the pixel electrode 190, the gate line, the data line and the thin film transistor TFT are arranged in the lower panel. In such an embodiment, the common electrode 270 (shown in FIG. Figure 3 The common electrode 270 is provided in the upper panel, and an opening is defined in the common electrode 270. The arrangement direction of the liquid crystal molecules included in the liquid crystal layer changes according to the electric field generated by the pixel electrode 190 and the common electrode 270. In an exemplary embodiment, the liquid crystal molecules are liquid crystals of a vertical alignment ("VA") mode in which the liquid crystal molecules are vertically aligned (e.g., aligned in a vertical direction relative to the upper panel or the lower panel) in the absence of an electric field.

[0077] The lower polarizer 310 and the upper polarizer 320 are disposed (e.g., attached) on both surfaces of the display panel 100. Since each of the two polarizers 310 and 320 has a transmission axis, light having polarization characteristics in a direction parallel to the transmission axis is transmitted, and light having polarization characteristics in a direction perpendicular to the transmission axis is blocked. The transmission axes of the two polarizers 310 and 320 may be perpendicular to each other.

[0078] The diffusion layer 330 is disposed on the upper polarizer 320. In an exemplary embodiment, the diffusion layer 330 has a characteristic of diffusing light in one direction. Here, the one direction may be a direction parallel to the short side direction of the liquid crystal panel, and the short side direction of the liquid crystal panel may be the same as the extending direction of the data line. That is, the diffusion layer 330 diffuses the light emitted toward the front surface of the liquid crystal panel to the short side direction of the liquid crystal panel, thereby obtaining an effect of improving the brightness when viewed in the upper side or lower side of the front surface of the liquid crystal panel.

[0079] In an exemplary embodiment, the backlight unit of the liquid crystal display includes a light source 410 , a light guide 400 , a reflective sheet 430 , and a prism sheet 420 .

[0080] The light source 410 includes a light emitting diode (“LED”), etc., and may emit light to be provided to the liquid crystal panel.

[0081] In an exemplary embodiment, if Figure 2 , light emitted from the light source 410 is incident on the side surface of the light guide 400. The light guide 400 transmits light to the end thereof where the light source 410 is not provided, and the reflective sheet 430 is constructed in such a manner that light is not emitted downward. The light incident on the reflective sheet 430 is reflected back to the light guide 400. The light passing through the light guide 400 and the reflective sheet 430 is incident on the prism sheet 420 provided thereon.

[0082] The prism sheet 420 includes a plurality of prism structural members arranged in parallel to each other, each prism structural member having a triangular cross-section and including a prism mountain-shaped member extending long in one direction. One corner of the triangular cross-section of the prism structural member forms the prism mountain-shaped member. The prism mountain-shaped member protrudes toward the rear surface of the liquid crystal display. In such an embodiment, the prism mountain-shaped member is arranged toward the light guide member 400 or the reflective sheet 430. In such an embodiment, the prism structural member is arranged at the lower surface of the prism sheet 420, and the upper surface of the prism sheet 420 facing the liquid crystal panel has a flat structure.

[0083] In an exemplary embodiment, the backlight unit may include a single prism sheet 420. In such an embodiment, the extension direction of the prism mountain-shaped member is only one direction. In such an embodiment, the extension direction of the prism mountain-shaped member is the short side direction of the liquid crystal panel. The short side direction of the liquid crystal panel is the same as the extension direction of the data line and the length direction of the pixel electrode 190.

[0084] Figure 2 A triangular cross-sectional structure cut along a direction perpendicular to the extending direction of the prism mountain-shaped members of the prism sheet 420 is shown.

[0085] In such an embodiment, since the prism sheet 420 is defined by a single sheet, a prism sheet matching the long side direction of the liquid crystal panel or having prism mountains extending in the same direction as the gate lines is not provided.

[0086] Such a prism sheet 420 has a prism mountain-shaped member extending in the short side direction of the liquid crystal panel (the direction of the data line), so that the light is refracted and travels in a direction perpendicular thereto. In such an embodiment, the light incident on the prism sheet 420 is refracted from the inclined prism surface to both sides based on the prism mountain-shaped member and travels in the left / right direction. As a result, the light traveling in the direction perpendicular to the short side direction of the liquid crystal panel (the direction of the data line) (the long side direction of the liquid crystal panel or the direction of the gate line) is further increased (refer to Fig.18 ).

[0087] In an exemplary embodiment, as described above, in the case of using a single prism sheet 420, light traveling in the long side direction of the liquid crystal panel is increased, so that light traveling in the short side direction of the liquid crystal panel can be relatively reduced. In such an embodiment, the liquid crystal panel includes a diffusion layer 330 on the display panel 100, and the diffusion layer 330 has a characteristic of diffusing light in the short side direction of the liquid crystal panel to compensate for the reduction of light traveling in the short side direction of the liquid crystal panel, so that light can be completely and uniformly transmitted (refer to Fig.21 ).

[0088] Will refer to below Figure 2 to describe the path that light takes.

[0089] The light emitted from the light source 410 is transmitted through the light guide 400, and the reflective sheet 430 disposed at the lower surface of the light guide 400 transmits the light emitted below the light guide 400 to the prism sheet 420 or the upper side. The light enters the lower polarizer 310 of the liquid crystal panel, and the light also includes the components of the light transmitted to the left and right directions (the long side direction of the liquid crystal panel) when the light passes through the prism sheet 420. Only the light having the same polarization characteristics as the transmission axis of the lower polarizer 310 is transmitted and enters the display panel 100. The phase delay of the light changes when passing through the liquid crystal layer of the display panel 100, so that the polarization characteristics of the light can be changed, and the transmission degree of the upper polarizer 320 changes according to the changed polarization characteristics of the light. The light passing through the upper polarizer 320 is diffused in the upward and downward directions (the short side direction of the liquid crystal panel) while passing through the diffusion layer 330, and the light whose characteristics are changed by the prism sheet 420 is used to display the image.

[0090] Figure 2An exemplary embodiment is shown in which the light source 410 is disposed at the side surface of the light guide 400. However, the invention is not limited thereto. According to an alternative exemplary embodiment, the backlight unit may have a direct-type structure in which a hole is defined in the reflective sheet 430 and the light source is disposed in the corresponding hole. In such an embodiment, a lens may be disposed on the light source, and the light guide may be omitted.

[0091] Next, refer to Figure 3 The patterns of the pixel electrodes and the common electrode in the structure of the display panel 100 are described.

[0092] Figure 3 is a top plan view illustrating the structure of a pixel electrode and a common electrode in a pixel according to an exemplary embodiment.

[0093] Figure 3 (A) in FIG. 1 shows a structure of a portion of the common electrode 270 corresponding to the pixel electrode 190 according to an exemplary embodiment. Figure 3 In (A), a longitudinal opening 271 and a notch opening 275 are defined in a common electrode 270 disposed in an upper panel. The longitudinal opening 271 extends in the same direction as the extending direction of the data line. In addition, a notch opening 275 may be defined for each pixel electrode 190, and the notch opening 275 may be disposed at a position corresponding to a predetermined position of the pixel electrode 190 in the longitudinal opening 271. The common electrode 270 is formed to be connected to each other between adjacent pixel electrodes 190.

[0094] In an exemplary embodiment, the cutout opening 275 may have one of various shapes, for example, a shape extending in a direction perpendicular to the longitudinal opening 271. Alternatively, the cutout opening 275 may be omitted.

[0095] In an exemplary embodiment, a protrusion structure may be provided in the common electrode 270 instead of the openings 271 and 275. The protrusion structure may be provided by forming an additional protrusion pattern on the common electrode 270.

[0096] Figure 3 (B) in FIG. 1 shows a structure of a pixel electrode 190 according to an exemplary embodiment. Figure 3 In (B), the pixel electrode 190 includes a longitudinal electrode 191 having a stripe shape, a transverse electrode 192 having a stripe shape, and a branch electrode 193 extending in an oblique direction from the longitudinal electrode 191 or the transverse electrode 192. The branch electrode 193 forms a predetermined angle α with the transverse electrode 192. Figure 3(B) in FIG. 1 shows an exemplary embodiment in which the branch electrode 193 forms an angle of about 45° with the transverse electrode 192. However, the invention is not limited thereto. According to an alternative exemplary embodiment, an angle exceeding 45° may be formed. In an exemplary embodiment, the pixel electrode 190 is divided into four domains by the longitudinal electrode 191 and the transverse electrode 192, and the branch electrodes 193 included in one domain may extend in directions parallel to each other and may be arranged at predetermined intervals.

[0097] Figure 3 (C) in FIG. 1 shows a structure in which the pixel electrode 190 and the common electrode 270 are arranged to overlap each other. Figure 3 As shown in (C) of FIG. 1 , when the upper panel including the common electrode 270 and the lower panel including the pixel electrode 190 are assembled, the pixel electrode 190 and the common electrode 270 are aligned to overlap each other.

[0098] like Figure 3 As shown in (C) of FIG. 1 , the longitudinal electrode 191 of the pixel electrode 190 overlaps the longitudinal opening 271 of the common electrode 270. In such an embodiment, the cutout opening 275 of the common electrode 270 is defined to overlap with a portion where the longitudinal electrode 191 and the transverse electrode 192 cross each other. In an exemplary embodiment, a portion of the pixel electrode 190 at which the longitudinal electrode 191 and the transverse electrode 192 cross each other has a width substantially the same as a width of the longitudinal electrode 191 or a width of the transverse electrode 192, so that the portion does not extend from the longitudinal electrode 191 and the transverse electrode 192.

[0099] Next, refer to Figure 4 To describe Figure 3 The arrangement direction of the liquid crystal molecules in the electrode structure.

[0100] Figure 4 It shows that according to Figure 3 Diagram of the arrangement of liquid crystal molecules in the electrode structure.

[0101] Hereinafter, an angle Φ will be used to describe the alignment of liquid crystal molecules, and the angle Φ is defined as follows.

[0102] The angle Φ of the liquid crystal molecule refers to the angle between the long axis of the liquid crystal molecule 305 and the transverse electrode 192 of the pixel electrode 190 after projecting the long axis direction of the liquid crystal molecule 305 having a three-dimensional structure onto the surface of the pixel electrode 190 parallel to the substrate surface of the display panel 100. The direction of the transverse electrode 192 is the same as the extending direction of the gate line, that is, the direction perpendicular to the direction of the longitudinal opening 271 and the longitudinal electrode 191.

[0103] Figure 4 (A) in FIG. 2 shows the shape of the liquid crystal molecules 305 arranged adjacent to the common electrode 270 .

[0104] Reference Figure 4 In (A), the liquid crystal molecules 305 adjacent to the common electrode 270 are arranged along one side edge of the longitudinal opening 271, and the long axis direction of the liquid crystal molecules 305 is aligned in a direction perpendicular to the longitudinal opening 271 (for example, the extension direction of the gate line). Therefore, the angle Φ of the liquid crystal molecules 305 is about 0°. In such an embodiment, the liquid crystal molecules 305 arranged near the edge of the cutout opening 275 are arranged in a direction different from the liquid crystal molecules 305 along the longitudinal opening 271. Except for the liquid crystal molecules 305 near the cutout opening 275, the long axis direction of the liquid crystal molecules 305 is completely aligned in a direction perpendicular to the longitudinal opening 271 (angle Φ is about 0°).

[0105] Figure 4 (B) in FIG. 1 shows the shape of the liquid crystal molecules 305 arranged adjacent to the pixel electrode 190 .

[0106] Reference Figure 4 In (B), the angle Φ of the liquid crystal molecules 305 disposed near the longitudinal electrode 191 of the pixel electrode 190 relative to the transverse electrode 192 is approximately 90°. In such an embodiment, the liquid crystal molecules 305 are arranged to be substantially parallel to the transverse electrode 192 on the right edge and the left edge of the pixel electrode 190, so that the angle Φ is almost 0°. The arrangement of the liquid crystal molecules 305 between the longitudinal electrode 191 and the left edge and between the longitudinal electrode 191 and the right edge (hereinafter referred to as the "middle portion") forms an intermediate angle of the two angles Φ on the portion where the longitudinal electrode 191 is disposed and the portion located at the left edge and the right edge, so that the angle Φ of the liquid crystal molecules 305 between the longitudinal electrode 191 and the left edge and between the longitudinal electrode 191 and the right edge is approximately 45°.

[0107] Figure 4 (A) in FIG. 1 shows a portion of the liquid crystal molecules 305 close to the upper panel in the liquid crystal layer, because the liquid crystal molecules 305 are close to the common electrode 270. Figure 4 (B) in FIG. 1 shows a portion of the liquid crystal molecules 305 close to the lower panel in the liquid crystal layer because the liquid crystal molecules 305 are close to the pixel electrode 190 .

[0108] Since the liquid crystal layer is disposed between the upper panel and the lower panel, the reference Figure 4 (C) in the description is set Figure 4 The angle Φ of the liquid crystal molecules between the liquid crystal molecules shown in (A) and (B) (ie, the angle Φ of the liquid crystal molecules in the intermediate layer which is deviated from the upper panel and the lower panel by a predetermined distance).

[0109] like Figure 4As shown in (C), the liquid crystal molecules 305 in the intermediate layer have a Figure 4 (A) and Figure 4 The liquid crystal molecules 305 in (B) have an angle Φ between the angles Φ of the liquid crystal molecules 305. In such an embodiment, since the angles Φ of 0° and 90° are formed on the portions corresponding to the longitudinal electrodes 191 and the longitudinal openings 271, the liquid crystal molecules 305 in the middle layer may have an angle of 45° as the middle angle therebetween. The liquid crystal molecules 305 in the middle layer corresponding to the left and right edges of the pixel electrode 190 have an angle of about 0° because the angle is 0° near the common electrode 270 and is almost 0° near the pixel electrode 190.

[0110] In such an embodiment, the liquid crystal molecules 305 of the intermediate layer corresponding to the intermediate portion are affected by the angles of all adjacent liquid crystal molecules, and as a result, an intermediate angle between 0° and 45° is formed.

[0111] Therefore, as described above, the liquid crystal molecules 305 disposed at the middle layer corresponding to the middle portion may be aligned at an angle of 45° or less.

[0112] In an exemplary embodiment, when the angle Φ of the liquid crystal molecules 305 is 45°, the transmittance has a maximum value, and the transmittance has a minimum value in the case of 0° or 90°. Figure 5 As described, in order to improve transmittance, it is desirable to increase the angle Φ of the liquid crystal molecules 305 in the middle layer corresponding to the middle portion to about 45°.

[0113] Figure 5 is a diagram illustrating an arrangement of liquid crystal molecules according to an angle of a branch electrode in a pixel electrode according to an exemplary embodiment.

[0114] exist Figure 5 , an exemplary embodiment in which the angle α between the branch electrode 193 and the transverse electrode 192 is 45° is shown on the left, and an exemplary embodiment in which the angle α is 60° or greater is shown on the right. Figure 5 Angle Φ of the liquid crystal molecules in the interlayer is shown.

[0115] First, if Figure 4 and Figure 5 As shown in FIG. 1 , the angle α between the branch electrodes 193 and the transverse electrodes 192 is about 45°, and the angle Φ of the liquid crystal molecules 305 may be less than about 45° in the middle layer corresponding to the middle portion.

[0116] In an exemplary embodiment, if Figure 5As shown in the right side of FIG. 1 , when the angle α of the branch electrodes 193 is about 60° or more, the angle Φ of the liquid crystal molecules 305 disposed at the middle layer corresponding to the middle portion may be about 45°.

[0117] As a result, in such an embodiment, the transmittance is increased. Figure 6 A change in transmittance according to the angle α of the branch electrodes 193 is described.

[0118] Figure 6 is a graph showing transmittance according to angles of branch electrodes in a pixel electrode according to an exemplary embodiment.

[0119] Figure 6 The transmittance according to the comparative example (reference SVA) and the transmittance variation of the angle α of the branch electrode 193 according to the exemplary embodiment (AVA) are shown.

[0120] First, the comparative example (reference SVA) has a structure in which the pattern of the pixel electrode 190 is the same as that of the exemplary embodiment described above, but no opening is separately formed in the common electrode 270, and when the transmittance of the comparative example (reference SVA) is considered to be 100, the change in transmittance in the exemplary embodiment is shown in FIG. Figure 6 middle.

[0121] Figure 6 The black lines in the diagram indicating the degree of transmission represent data lines, gate lines, storage electrodes, etc. Figure 6 In the diagram, two lines vertically crossing the center of the pixel electrode correspond to the data lines, horizontal lines arranged above and below the pixel electrode correspond to the gate lines, and lines arranged near the two edges of the pixel electrode correspond to the storage electrodes.

[0122] exist Figure 6 , when the angle α of the branch electrode 193 is about 45°, the transmittance is improved to 106% compared with the comparative example. It can be shown that due to the longitudinal opening 271 formed in the common electrode 270, the black color is reduced at the longitudinal electrode 191 portion of the pixel electrode 190, and as a result, the transmittance is improved.

[0123] exist Figure 6 In FIG. 1 , when the angle α of the branch electrode 193 is about 55°, it can be shown that the transmittance is improved to 118%. When the angle α of the branch electrode 193 increases and then the angle of the liquid crystal molecules disposed at the corresponding portion increases to nearly 45°, the transmittance is improved.

[0124] Figure 6The figure on the right side of FIG. 1 shows two exemplary embodiments in which the angle α of the branch electrode 193 is about 65°. The second figure from the right side shows an exemplary embodiment in which the angle α of the branch electrode 193 is 65° (ie, AVA α=65° (opening)). Figure 3 As shown in FIG. 2(B) , the pixel electrode 190 includes a vertical electrode 191 , a horizontal electrode 192 , and branch electrodes 193 .

[0125] like Figure 6 , the diagram at the far right shows an exemplary embodiment having strip-shaped edge lateral electrodes disposed above and below the pixel electrode 190 (ie, AVA α=65° (closed)).

[0126] In such an embodiment, reference Figure 6 When the angle α of the branch electrode 193 is 65° and an edge transverse electrode is additionally formed in the pixel electrode 190, a maximum transmittance of 125% can be obtained. Figure 6 Comparing the rightmost figure in FIG. 1 with the second right figure, it can be shown that the black level is different in the portion adjacent to the edge lateral electrode. That is, the transmittance of the corresponding portion is improved due to the edge lateral electrode (i.e., compensated by the closed pattern), so that the transmittance is increased from 123% to 125%.

[0127] Next, refer to Figure 7 Describe in detail Figure 6 The rightmost structure of .

[0128] Figure 7 is a diagram of a structure of a pixel electrode, an arrangement of liquid crystal molecules, and transmittance according to an exemplary embodiment.

[0129] First, the structure of the pixel electrode 190 will be described.

[0130] According to an exemplary embodiment, Figure 7 As shown in FIG. 1 , one pixel electrode 190 includes a longitudinal electrode 191, a transverse electrode 192, a branch electrode 193, and an edge transverse electrode 196 connecting the branch electrode 193 and the longitudinal electrode 191. The edge transverse electrode 196 may be parallel to the transverse electrode 192. The branch electrode 193 forms an angle α of about 65° with the transverse electrode 192. The edge transverse electrode 196 connects the upper ends of the branch electrodes 193 so that the upper ends of the branch electrodes 193 are not opened. In such an embodiment, the four domains defined by the longitudinal electrode 191 and the transverse electrode 192 have a structure that is open on the left and right edges and closed on the upper and lower edges.

[0131] The common electrode 270 has Figure 3In such an embodiment, the common electrode 270 includes a longitudinal opening 271 and a notch opening 275, the longitudinal opening 271 is arranged at a position overlapping the longitudinal electrode 191, and the notch opening 275 is formed to overlap with the position where the longitudinal electrode 191 and the transverse electrode 192 cross each other.

[0132] In such an embodiment, as described above, the angle Φ of the liquid crystal molecules 305 disposed at various positions is about 45°. Therefore, the transmittance is substantially high.

[0133] Reference Figure 7 If the branch electrodes 193 have an angle with the transverse electrode 192 in the range of about 60 degrees to about 80 degrees, the angle Φ of the liquid crystal molecules 305 corresponding thereto is about 45°, so that the transmittance is improved.

[0134] Next, refer to Figure 8 A difference in transmittance according to a comparative example (SVA) and an exemplary embodiment (AVA) will be described.

[0135] Figure 8 is a graph showing transmittance according to a comparative example and an exemplary embodiment.

[0136] First, the comparative example on the left side has a structure in which an opening is not formed in the common electrode 270, and the exemplary embodiment on the right side has a structure in which an opening is not formed in the common electrode 270. Figure 7 The structure shown in .

[0137] The transmittance at the same position for the left and right pixels is shown in the middle graph. In the graph, the vertical axis represents the transmittance and the horizontal axis represents the distance from the left end of the pixel. The width of the pixel electrode in the exemplary embodiment is about 60 micrometers (μm).

[0138] In an exemplary embodiment, if Figure 8 As shown in the graph of , the transmittance is improved at the edge of the pixel electrode, and the transmittance is also improved near the longitudinal electrode 191 of the pixel electrode 190 due to the longitudinal opening 271 of the common electrode 270. Therefore, the overall transmittance can be improved by about 25%.

[0139] Next, refer to Fig. 9 To describe the arrangement of liquid crystal molecules.

[0140] Fig. 9 are diagrams illustrating arrangements of liquid crystal molecules according to comparative examples and exemplary embodiments.

[0141] exist Fig. 9 In FIG. 1 , the liquid crystal molecules of the exemplary embodiment are indicated by 305, and the liquid crystal molecules of the comparative example are indicated by 305-1. Fig. 9 In, with Figure 8 Arrangements of liquid crystal molecules of the corresponding comparative example and exemplary embodiment are shown to be overlapped.

[0142] The liquid crystal molecules 305-1 of the comparative example and the liquid crystal molecules 305 of the exemplary embodiment are similar at most positions, and the angles of the portion where the longitudinal opening 271 of the common electrode 270 is provided are substantially different from each other. It can be shown that the liquid crystal molecules 305 of the exemplary embodiment are arranged at an angle corresponding to about 45° so that the transmittance is high, and the liquid crystal molecules 305-1 of the corresponding portion of the comparative example are arranged in a direction close to the vertical direction so that the transmittance is low.

[0143] Next, refer to Fig.10 Changes in transmittance characteristics according to the position and presence of the notch opening 275 will be described.

[0144] Fig.10 is a graph illustrating a characteristic change according to a change of a cutout in a common electrode according to an exemplary embodiment.

[0145] exist Fig.10 middle, Fig.10 (C) and Fig.10 (D) in FIG. 1 shows an exemplary embodiment of a pixel electrode 190 including an edge transverse electrode 196 in which the common electrode 270 includes only a longitudinal opening 271. Fig.10 (A) and Fig.10 (B) shows an exemplary embodiment in which the common electrode 270 includes both the longitudinal opening 271 and the cutout opening 275 .

[0146] in addition, Fig.10 (B) and Fig.10 (D) in FIG. 1 shows an exemplary embodiment in which the position of the longitudinal opening 271 is set at a position that does not correspond to the longitudinal electrode 191 of the pixel electrode 190 (ie, is shifted relative to the longitudinal electrode 191 of the pixel electrode 190 ).

[0147] In short, if Fig.10 As shown in FIG. 1 , even if the position of the longitudinal opening 271 does not correspond to and does not match the longitudinal electrode 191, the change in transmittance is substantially small. Fig.10 As shown, spots may be visible.

[0148] In an exemplary embodiment without the cutout opening 275, as shown Fig.10 (C) and Fig.10 As shown in (D) in FIG. 5 , the transmittance slightly increases from 123% to 125%.

[0149] In the exemplary embodiment where the notch opening 275 exists, even if four domains overlap each other, the arrangement direction of the liquid crystal molecules may be effectively determined, and thus, the liquid crystal molecules may be substantially stable.

[0150] Next, refer to Fig.11 To describe the characteristics of the side surface.

[0151] Fig.11 : is a graph showing changes in brightness in the front and side surfaces according to a comparative example and an exemplary embodiment.

[0152] The front side refers to the front side of the liquid crystal panel, and the side side refers to the side side when the viewing angle moves from the front side of the liquid crystal panel to the long side direction. Fig.11 (A) shows a comparative example, Fig.11 (B) in FIG. 1 shows an exemplary embodiment. Fig.11 In the graph of , the horizontal axis represents voltage, and the vertical axis represents transmittance at a position of 60 degrees on the side. The transmittance of 100% is based on the maximum transmittance at the front of the comparative example.

[0153] like Fig.11 As shown in (A) in the comparative example, when the voltage is in the region of about 2.4 volts (V) to about 4 V, there is a region where the front transmittance is smaller than the side transmittance. Fig.11 In the figure, a picture showing the characteristics of the side according to the voltage of the part is added. As indicated by the picture, the light leakage phenomenon occurs at the side in the comparative example, so that the transmittance higher than the front transmittance occurs. In addition, it can be shown that the position of the light leakage is the middle part.

[0154] like Fig.11 As shown in (B) in FIG. 1 , in an exemplary embodiment, it can be shown that light does not leak from the side even at low grayscale, thus maintaining low transmittance. As a result, in an exemplary embodiment, grayscale inversion does not occur on the side.

[0155] Conventionally, when grayscale inversion occurs on the side as in the comparative example, a method is generally used in which one pixel electrode is divided into a sub-pixel electrode for displaying high grayscale and another sub-pixel electrode for displaying low grayscale to be identified on the side with an average value of high grayscale and low grayscale, thereby removing the grayscale inversion on the side. When one pixel includes two sub-pixel electrodes as described above, at least two thin film transistors are provided for one pixel, so that the structure of the pixel becomes complicated. In addition, when a pixel is formed in a small area to achieve high resolution, such a structure is not effectively formed in such a small area for the pixel.

[0156] In an exemplary embodiment, since grayscale inversion does not occur on the side, one pixel may have a structure including only a single pixel electrode and a single thin film transistor, so that the pixel structure may be efficiently formed in a small area to achieve high resolution.

[0157] In such an embodiment, Fig.11 As shown in , when high grayscale can be displayed with high transmittance, high brightness images can also be effectively displayed on the side.

[0158] Next, refer to Fig.12 To describe the angle Φ of the liquid crystal molecules on the side under a predetermined voltage.

[0159] Fig.12 is a graph showing alignment characteristics of liquid crystal molecules according to voltage at a specific position in a comparative example and an exemplary embodiment.

[0160] Fig.12 (A) shows a comparative example, Fig.12 (B) in FIG. 1 shows an exemplary embodiment. Fig.12 In each figure, the angle Φ of the liquid crystal molecules at the portion indicated by the circle is shown. Fig.12 In the comparative example of (A) in FIG. 1 , for example, when a voltage of 3 V is applied to the pixel electrode, an angle Φ of the liquid crystal molecules at a portion indicated by a circle is 35°.

[0161] Reference Fig.12 (A) in FIG. 3 shows that the liquid crystal molecule 305-1 has a substantially constant angle Φ regardless of the voltage. Considering that the maximum transmittance occurs when the liquid crystal molecule 305-1 is 45°, in the corresponding portion, since the maximum transmittance occurs at most voltages, the problem that the transmittance does not change according to the grayscale occurs.

[0162] In an exemplary embodiment, if Fig.12 As shown in (B) of FIG. 3 , the angle Φ of the liquid crystal molecules 305 increases according to the increase of the applied voltage. In such an embodiment, grayscale representation is effectively achieved on the side.

[0163] Already referred to Fig.12 The angle Φ of the liquid crystal molecules based on the predetermined position of the pixel electrode is described. Next, reference will be made to Fig.13 The angle Φ of the liquid crystal molecules at three different positions in one domain based on the pixel electrode is described.

[0164] Fig.13 is a graph showing angles at various positions of liquid crystal molecules according to voltages in a comparative example and an exemplary embodiment.

[0165] Fig.13(A) shows a comparative example, Fig.13 (B) in FIG. 1 shows an exemplary embodiment.

[0166] As in Fig.13 (A) and Fig.13 As shown in the arrangement diagram of liquid crystal molecules for 3 V at the bottom of (B) in FIG. 1 , the angle Φ of the liquid crystal molecules according to each voltage is shown for three parts (edge, middle, ridge) in one domain.

[0167] In the comparison example, Fig.13 As shown in (A) in FIG. 1 , for each voltage, the angle Φ of the liquid crystal molecules on the edge, the angle Φ of the liquid crystal molecules on the middle, and the angle Φ of the liquid crystal molecules on the ridge adjacent to the longitudinal electrode 191 are substantially different from each other.

[0168] In an exemplary embodiment, if Fig.13 As shown in (B) in FIG. 5 , the difference in the angle Φ of the liquid crystal molecules on the edge, the middle, and the ridge is significantly reduced.

[0169] like Fig.13 As shown in FIG. 1 , since the transmittance T is a function of the double angle of the liquid crystal molecules in the sine function (i.e., Φ) is proportional to the square of the value obtained (i.e., ), therefore, a spot may be recognized at a specific portion in the comparative example due to a significant difference in transmittance according to its position. In the comparative example, when the voltage has a predetermined value or more, the transmittance at the ridge or the middle may be limited.

[0170] In an exemplary embodiment, the angle Φ of the liquid crystal molecules changes according to the change of the voltage on the edge, the middle and the ridge, thereby changing the transmittance, so that the gray scale can be effectively presented. In such an embodiment, the angle Φ of the liquid crystal molecules is similar to each other on the edge, the middle and the ridge at the same voltage, so that spots that appear when the brightness of each part is different from each other can be effectively prevented.

[0171] In an exemplary embodiment, when a low gray scale is displayed by supplying a low voltage, the angle Φ of the liquid crystal molecules is also small, and when a high gray scale is displayed by supplying a high voltage, the angle Φ of the liquid crystal molecules is large. In such an embodiment, Fig.13 As indicated by "Auto-Steering" in (B), the angle Φ of the liquid crystal molecules is automatically adjusted according to the voltage or grayscale. However, in the comparative example, the angle Φ of the liquid crystal molecules does not change much according to the voltage, so that "auto-steering" does not occur.

[0172] Already referred to Figure 3 and Figure 7Structures of exemplary embodiments of a pixel electrode and a common electrode are described.

[0173] Next, refer to Fig.14 Various exemplary embodiments of the pixel electrode and the common electrode are described below.

[0174] Fig.14 is a diagram illustrating structures of a pixel electrode and a common electrode according to various exemplary embodiments.

[0175] exist Fig.14 , the structures of various embodiments of the pixel electrode 190 are shown. In such an embodiment, the pixel electrode 190 includes a longitudinal electrode 191, a transverse electrode 192, and a branch electrode 193, and an edge transverse electrode 196 having a strip shape or an edge longitudinal electrode 195 having a strip shape is additionally provided. The branch electrode 193 may include a non-inclined portion, and in an exemplary embodiment, the number of the transverse electrode 192 or the longitudinal electrode 191 may be two. In such an embodiment, as Fig.14 As shown in FIG. 2 , the structure of the common electrode 270 includes both a longitudinal opening 271 and a cutout opening 275 .

[0176] First, we will describe Fig.14 An exemplary embodiment of (A) in .

[0177] Fig.14 The pixel electrode 190 of (A) includes a longitudinal electrode 191 and a transverse electrode 192 and a plurality of branch electrodes 193 extending therefrom in an oblique direction. The edge transverse electrode 196 or the edge longitudinal electrode 195 is disposed at the ends of the plurality of branch electrodes 193, thereby having a closed structure in which the ends of the branch electrodes 193 are not open. In such an embodiment, the edge transverse electrode 196 is not disposed at the branch electrode 193 extending in the downward direction. The edge transverse electrode 196 disposed at the upper side and the edge longitudinal electrode 195 disposed at the left side are connected to each other, however, the edge longitudinal electrode 195 disposed at the right side is not connected to the edge transverse electrode 196 disposed at the upper side. In such an embodiment, the detailed connection structure may be variously modified.

[0178] The longitudinal opening 271 of the common electrode 270 is defined at a portion thereof corresponding to the longitudinal electrode 191 , and a cutout opening 275 is defined corresponding to a portion where the longitudinal electrode 191 and the transverse electrode 192 cross each other.

[0179] In an alternative exemplary embodiment, if Fig.14 As shown in (B) of FIG. 1 , the edge transverse electrode 196 may be disposed at a lower portion of the pixel electrode 190. In such an embodiment, the edge longitudinal electrode 195 disposed at the left side is connected to the edge transverse electrode 196 disposed at the upper side.

[0180] In addition to the edge transverse electrode 196 and the edge longitudinal electrode 195 being disconnected, Fig.14 The structure of (C) in Fig.14 The structure of (B) is similar. Fig.14 As shown in (C) , one side end of the transverse electrode 192 extends and is not connected to the edge longitudinal electrode 195 on the right side.

[0181] Fig.14 The structure of (D) includes the edge longitudinal electrode 195, but does not include the edge transverse electrode 196. Fig.14 As shown in (D) in FIG. 1 , the branch electrode 193 includes a portion that does not advance obliquely. That is, the branch electrode 193 has a structure extending from the longitudinal electrode 191 in a horizontal direction and bending in an oblique direction. However, according to an alternative exemplary embodiment, the branch electrode 193 may have a structure extending from the longitudinal electrode 191 in an oblique direction and then extending in a vertical direction or a horizontal direction while being bent.

[0182] In addition to its structure also including edge lateral electrodes 196, Fig.14 (E) and Fig.14 Similar to (D).

[0183] Fig.14 (F) in FIG. 1 shows an exemplary embodiment including two transverse electrodes 192 , wherein the longitudinal electrode 191 and the transverse electrode 192 cross each other at two locations so that two cutout openings 275 of the common electrode 270 are defined. Fig.14 In the exemplary embodiment of (F), the branch electrodes 193 of the pixel electrode 190 are arranged at different intervals at different angles. In such an embodiment, a gap or distance between two adjacent branch electrodes 193 is narrow at one end and wide at the other end.

[0184] Fig.14 (G) in FIG. 1 shows an embodiment having a structure in which the features of the exemplary embodiments of the invention described above are combined. In such an embodiment, the branch electrode 193 is obliquely formed at a portion close to the transverse electrode 192 (i.e., the upper and lower portions of the transverse electrode 192). In such an embodiment, the branch electrodes 193 of the curved structure are arranged at both sides thereof. In such an embodiment, the uppermost and lowermost branch electrodes 193 have a structure that is obliquely arranged without being bent again. The edge electrodes 195 and 196 for each portion are arranged to have a closed structure, and the transverse electrode 192 has a structure in which the end portion does not extend further to connect to the edge longitudinal electrode 195.

[0185] Fig.14(H) in FIG. 1 shows an exemplary embodiment in which the pixel electrode 190 has two longitudinal electrodes 191 and one transverse electrode 192. In such an embodiment, since there are two locations where the transverse electrode 192 and the longitudinal electrode 191 cross each other, two cutout openings 275 are defined corresponding to the crossing portions. Fig.14 The exemplary embodiment of (H) in FIG. 1 shows a structure without the edge electrodes 195 and 196 , but is not limited thereto. Alternatively, at least one of the edge electrodes 195 and 196 may be included.

[0186] Fig.14 The structure of the pixel electrode 190 shown in FIG. 1 only shows some exemplary embodiments of the invention, and the invention is not limited thereto. Such embodiments can be variously modified by combining the features described above.

[0187] Fig.14 The structure of the common electrode 270 in an exemplary embodiment is shown. In such an embodiment, the common electrode 270 includes a longitudinal opening 271 and a cutout opening 275 having a rhombus shape.

[0188] However, the structure of the common electrode 270 may be modified in various ways. Fig.15 The structure of the common electrode 270 in the exemplary embodiment is described.

[0189] Fig.15 is a diagram illustrating a structure of a common electrode according to various exemplary embodiments.

[0190] Fig.15 (A) in FIG. 1 shows an exemplary embodiment in which the common electrode 270 has the structure described above. Fig.15 The cutout opening 275 of (A) may have one of various shapes such as a rhombus, a circle, or an octagon.

[0191] In an alternative exemplary embodiment, if Fig.15 As shown in FIG. 2(B) , the common electrode 270 may not include the cutout opening 275 .

[0192] Fig.15 (C) shows another alternative exemplary embodiment in which the cutout opening 275 of the common electrode 270 may have a long elongated shape. In such an embodiment, the cutout opening 275 may extend in the horizontal direction and may be disposed at a position corresponding to the transverse electrode 192 among the pixel electrodes 190. Fig.15 The cutout opening 275 shown in (C) may have a structure extending from a portion where the transverse electrode 192 and the longitudinal electrode 191 cross each other and extending to a predetermined position of the transverse electrode 192 .

[0193] Hereinafter, features of an exemplary embodiment having the above-described pixel structure will be described in detail.

[0194] Fig.16 is a diagram showing light leakage in an upper side of an arrangement for liquid crystal molecules according to an exemplary embodiment, Fig.17 is a graph showing characteristics according to positions for arrangement of liquid crystal molecules according to an exemplary embodiment.

[0195] like Fig.13 As shown in (B) of FIG. 1 , in an exemplary embodiment, when a low voltage is applied to the pixel electrode, the angle Φ of the liquid crystal molecules may be small.

[0196] Fig.16 The case where the angle Φ of the liquid crystal molecules 305 is arranged to be small and the case where the user views the liquid crystal molecules 305 from the side and from above are shown.

[0197] When the angle Φ of the liquid crystal molecule 305 is small, when the user views the liquid crystal molecule 305 from the side, there is no light leakage because one end of the liquid crystal molecule 305 is seen. However, when viewed from above, light leakage occurs because the side of the liquid crystal molecule 305 is seen.

[0198] like Fig.16 As shown in the graph at the bottom of , when a voltage of 3 V is applied, when viewed from the side (horizontal side viewing angle), the transmittance is low, so that light leakage does not occur. However, when viewed from the upper side (vertical side viewing angle), the transmittance is high, so that light leakage occurs.

[0199] In an exemplary embodiment, the transmittance measured according to the angle of the side surface may be as follows: Fig.17 as shown in .

[0200] Fig.17 A result (A) having a shape close to a circle and a result (B) having a shape similar to the shape of the number "8" are shown. Each result is a line connecting the transmittance at a specific angle. Here, the result (B) is also called an 8-shaped brightness distribution.

[0201] First, the result (A) is obtained by measuring the transmittance at various angles in the case of the comparative example, in which the transmittance is relatively large at the upper side and the lower side, and the transmittance is substantially uniform.

[0202] In an exemplary embodiment, as shown by the result (B), the transmittance is low while concave when viewed from the right and left sides, and the transmittance is very high in the upper and lower sides. When a low voltage is applied to display a low grayscale, the high transmittance due to light leakage at the upper and lower viewing angles is undesirable.

[0203] In an exemplary embodiment, as described above with reference to Figure 2 As described, the prism mountain-shaped member is positioned toward the light guide member, and the extension direction of the prism mountain-shaped member is formed in the same direction as the short side direction of the liquid crystal panel (ie, the length direction of the pixel electrode or the extension direction of the data line).

[0204] Such a structure of the prism sheet 420 has a property of transmitting light to the left and right, thereby preventing light from being transmitted upward and downward.

[0205] Fig.18 Characteristics of light passing through the backlight unit when such a prism sheet 420 is included are shown.

[0206] Fig.18 is a graph illustrating characteristics of light provided from a backlight unit of a liquid crystal display according to an exemplary embodiment.

[0207] Generally, since there is no directivity, the light provided from the backlight unit to the liquid crystal display exhibits a constant brightness in a circular shape (also referred to as a circular brightness distribution). Fig.18 As shown in , light provided from the backlight unit to the liquid crystal display can have relatively high brightness on the left and right sides and relatively low brightness on the upper and lower sides, so that because the prism sheet 420 is oriented in such a manner that the prism mountain-shaped member faces the light guide member and the extension direction of the prism mountain-shaped member is arranged in the same direction as the length direction of the pixel electrode (i.e., the extension direction of the data line), the brightness is displayed in an elliptical shape that spreads widely to the left and right (hereinafter, referred to as an elliptical brightness distribution).

[0208] In the following, reference will be made to Fig.19 Characteristics of light emitted from the backlight unit of the comparative example and the backlight unit of the exemplary embodiment will be described.

[0209] Fig.19 2 is a graph showing characteristics of a prism sheet according to a comparative example and characteristics of a prism sheet according to an exemplary embodiment.

[0210] Fig.19 The characteristics of light emitted from the backlight unit according to the exemplary embodiment (reverse prism) and the comparative example (orthogonal prism) are shown. In the case of the comparative example, the prism mountain is arranged toward the display panel, two prism sheets are used, and the extension directions of the prism mountain of the two prism sheets are perpendicular to each other. In such a structure, since the extension directions of the prism mountain are two directions perpendicular to each other, light propagates not only in the left-right direction but also in the up-down direction. As a result, compared with Fig.18 Instead, the light has a circular brightness distribution.

[0211] Fig.19(A) in FIG. 1 shows the amount of light in a direction perpendicular to the extending direction of the prism mountain-shaped member (ie, in the side surface) in the exemplary embodiment (reverse prism). Fig.19 As shown in (A) in FIG. 1 , in the exemplary embodiment, the half width (i.e., the width of the portion having 50% of the light amount) is 18° (the angle on one side is 9° so that the angle on both sides is 18°). When compared with the case of the comparative example (orthogonal prism or C prism), the half width is smaller by about 19°, which is smaller by 38° as a whole.

[0212] Fig.19 (B) in the figure shows the amount of light viewed from the same direction as the extension direction of the prism mountain-shaped member of the exemplary embodiment (reverse prism or R prism) (i.e., from the upper side or the lower side), and such amount of light can be basically the same as the amount of light of the comparative example (C prism).

[0213] This is because the characteristic has an elliptical brightness distribution due to the prism sheet 420 .

[0214] Will refer to Fig. 20 Characteristics of an exemplary embodiment including the prism sheet 420 and the pixel structure described above are described in more detail.

[0215] Fig. 20 is a graph showing characteristics changed by using a prism sheet according to an exemplary embodiment.

[0216] Fig. 20 (A) shows the brightness distribution according to the angle in the exemplary embodiment. Fig.17 The brightness distribution of the character “8” is shown in FIG.

[0217] Fig. 20 (B) in FIG. 4 shows the brightness distribution after being compensated by the prism sheet 420 in the exemplary embodiment.

[0218] Fig. 20 (B) in FIG. 1 shows a nearly circular brightness distribution at the center, which is consistent with the brightness distribution through the prism sheet 420 and Fig. 20 That is, the prism sheet 420 has a brightness that is concave in the side (where light is provided laterally through the prism sheet 420), so that a higher brightness occurs. On the other hand, in Fig. 20 In (A), since less light is provided to the upper and lower sides through the prism sheet 420, high brightness due to light leakage from the upper and lower sides is weakened, thereby displaying relatively low brightness.

[0219] In an exemplary embodiment, as described above, the prism sheet 420 is oriented in such a manner that the prism mountain faces the light guide and the extension direction of the prism mountain is the same as the length direction of the pixel electrode (i.e., the extension direction of the data line), so that compensation occurs in pixels having the pattern of the pixel electrode and the pattern of the common electrode described above.

[0220] Next, refer to Fig.21 The brightness distribution of light according to each position of the display device will be described. Specifically, the change of the brightness distribution of light passing through the diffusion layer 330 will be described in detail.

[0221] Fig.21 is a graph showing characteristics of light at each position of a liquid crystal display according to an exemplary embodiment.

[0222] Fig.21 Schematically shows Figure 2 The liquid crystal display shown in FIG. Fig.21 A light source 410 is also shown supported behind the light guide 400 , and a light source substrate 411 for supplying power to the light source 410 is also shown. Fig.21 It is also shown that the liquid crystal display may further include a housing 500 such as a base for accommodating the display panel and the backlight unit together.

[0223] Fig.21 The brightness distribution of light passing through the light guide member (LGP) 400, the brightness distribution of light passing through the prism sheet 420, and the brightness distribution of light emitted from the liquid crystal display (LOP / panel) are respectively shown.

[0224] First, in Fig.21 (A) in FIG. 4 shows light incident on the prism sheet 420 after passing through the light guide 400. The light from the light guide 400 is incident on the prism sheet 420 with a brightness distribution similar to a circular shape.

[0225] exist Fig.21 (B) in FIG. 4 shows the brightness distribution of the light emitted after being incident on the prism sheet 420 (eg, R prism). Fig.21 As shown in (B) of FIG. 4 , light propagates to the left and right sides through the prism sheet 420 and does not propagate vertically, thereby having an elliptical-shaped brightness distribution on the side.

[0226] The light emitted from the prism sheet 420 passes through the lower polarizer 310, the display panel 100, the upper polarizer 320, and the diffusion layer 330 to be recognized by the user. Fig.21 (C) in FIG. 1 shows the brightness distribution of the light emitted through the diffusion layer 330 .

[0227] exist Fig.21 In the brightness distribution of (C), Fig.21Compared with the brightness distribution of (B) in FIG. 1 , the brightness increases at the upper and lower sides. This is because the diffusion layer 330 in the exemplary embodiment may have the property of diffusing light in the up and down directions. In such an embodiment, the prism sheet 420 transmits light in the right and left directions, so that the light is reduced in the up and down directions. However, in such an embodiment, since the diffusion layer 330 diffuses in the up and down directions, the light in the up and down directions is compensated and displayed.

[0228] Fig.21 An exemplary embodiment in which the light source 410 is disposed at one side of the light guide is shown, but is not limited thereto. Alternatively, the light source 410 may be disposed below the display panel (a direct-down structure). When the light source 410 has a direct-down light source, a hole may be defined in the reflective sheet 430, and the light source may be disposed in the hole. In such an embodiment, a lens may be additionally disposed on the light source. In such an embodiment having a direct-down structure, the characteristics of the light provided to the prism sheet 420 are not significantly changed, and the prism sheet 420 may be applied. Fig.21 The brightness distribution is shown in .

[0229] While the invention has been described in connection with what are presently considered to be practical exemplary embodiments, it will be understood that the invention is not limited to the disclosed embodiments, but on the contrary is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the claims.

Claims

1. A liquid crystal display, comprising: A liquid crystal panel, comprising a liquid crystal layer, a pixel electrode and a common electrode; as well as a backlight unit including a light source, wherein the backlight unit provides light to the liquid crystal panel, Wherein, the pixel electrode comprises: A longitudinal electrode having a strip shape and extending in a vertical direction; a transverse electrode having a strip shape, crossing the longitudinal electrode and extending in a horizontal direction; and a branch electrode having a strip shape, extending from the longitudinal electrode or the transverse electrode, and comprising an inclined portion extending in an inclined direction relative to the longitudinal electrode or the transverse electrode, wherein the common electrode has a longitudinal opening and a notch opening, the longitudinal opening overlaps the longitudinal electrode of the pixel electrode and extends in the vertical direction, the notch opening has a width extending at the longitudinal opening and overlaps a portion where the longitudinal electrode and the transverse electrode intersect each other, The width of the portion of the pixel electrode at which the longitudinal electrode and the transverse electrode cross each other is the same as the width of the transverse electrode or the width of the longitudinal electrode, The longitudinal opening of the common electrode only defines the common electrode corresponding to the pixel electrode into two separate parts, and The cutout opening has a diamond shape, a circular shape, or an octagonal shape instead of an elongated shape.

2. The liquid crystal display according to claim 1, wherein: The pixel electrode further includes an edge transverse electrode, which has a strip shape, extends in the horizontal direction, and is connected to the end of the longitudinal electrode. The edge lateral electrodes are connected to ends of the branch electrodes, and The inclined portion of the branch electrode forms an angle with the lateral electrode in a range of 60 degrees to 80 degrees.

3. The liquid crystal display according to claim 1, wherein: The pixel electrode further includes an edge longitudinal electrode, which has a strip shape, is connected to an end of the transverse electrode, and is parallel to the longitudinal electrode.

4. The liquid crystal display according to claim 1, wherein: The pixel electrode further includes an edge longitudinal electrode, which has a strip shape and is parallel to the longitudinal electrode, and The edge longitudinal electrodes are connected to ends of the branch electrodes and are not connected to the transverse electrodes.

5. The liquid crystal display according to claim 1, wherein: The branch electrode further includes a portion parallel to the transverse electrode or the longitudinal electrode, thereby defining a bent structure with the inclined portion.

6. The liquid crystal display according to claim 1, wherein: The pixel electrode includes a first pixel electrode and a second pixel electrode adjacent to each other, The liquid crystal panel further includes a first gate line, a second gate line, a first data line, a second data line, a first thin film transistor and a second thin film transistor. The first thin film transistor is connected to the first pixel electrode and is connected to the first gate line and the first data line. The second thin film transistor is connected to the second pixel electrode, and is connected to the second gate line and the second data line. The first gate line and the second gate line receive the same gate signal as each other, The first pixel electrode and the second pixel electrode are arranged along an extending direction of the first data line and the second data line, and The first data line and the second data line are disposed to cross the first pixel electrode and the second pixel electrode, respectively.

7. The liquid crystal display according to claim 1, wherein: The liquid crystal panel further includes an upper polarizer and a lower polarizer respectively attached to both sides of the liquid crystal panel, The backlight unit further includes a prism sheet disposed below the liquid crystal panel and a reflective sheet disposed below the prism sheet. The prism sheet has a prism mountain-shaped piece, and the prism mountain-shaped piece is arranged toward the reflection sheet, The extending direction of the prism mountain-shaped member is the same as the short side direction of the liquid crystal panel. does not include a prism mountain-shaped member extending in the long side direction of the liquid crystal panel, The backlight unit further includes a light guide member located between the prism sheet and the reflective sheet, and The light source is disposed at one side of the light guide.

8. The liquid crystal display according to claim 7, wherein: The liquid crystal panel further includes a diffuser attached to an upper surface of the upper polarizer, and The diffuser diffuses light incident on the diffuser in the short side direction of the liquid crystal panel.

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