LIQUID CRYSTAL DISPLAY APPARATUS

A liquid crystal display apparatus includes data lines extending in a first direction, gate lines extending in a second direction crossing the first direction, and pixels respectively connected to the data lines and the gate lines, each of the pixels including a liquid crystal layer, in which the first direction is parallel to an initial orientation direction of the liquid crystal layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from and the benefit of Korean Patent Application No. 10-2015-0180188, filed on Dec. 16, 2015, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

Field

Exemplary embodiments relate to liquid crystal display apparatuses. More particularly, exemplary embodiments relate to liquid crystal display apparatuses having reduced light leakage and disclination.

Discussion of the Background

As various electronic devices, such as, mobile phones, personal data assistants (PDAs), computers, and large TVs have been developed, demand for flat panel display apparatuses for electronic devices has gradually increased. Among flat panel display apparatuses, liquid crystal display (LCD) apparatuses have advantages over other display apparatuses in that LCD apparatuses have low power consumption, easily display a motion picture, and have a high contrast ratio.

An LCD apparatus includes a liquid crystal layer between two display sheets, and displays an image by controlling incident light to be transmitted or blocked by each pixel by changing the polarizing direction of the incident light through changing the arrangement direction of liquid crystal molecules in the liquid crystal layer, by applying an electric field to the liquid crystal layer.

SUMMARY

Exemplary embodiments include liquid crystal display apparatuses having data lines inclined at a constant direction.

Additional aspects will be set forth in part in the description which follows, and, in part, will be apparent from the disclosure, or may be learned by practice of the inventive concept.

According to an exemplary embodiment of the present invention, a liquid crystal display apparatus includes data lines extending in a first direction, gate lines extending in a second direction crossing the first direction, and pixels respectively connected to the data lines and the gate lines, each of the pixels including a liquid crystal layer, in which the first direction is parallel to an initial orientation direction of the liquid crystal layer.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIG. 1is a schematic plan view of a liquid crystal display apparatus500according to an exemplary embodiment of the present invention.

Referring toFIG. 1, the liquid crystal display apparatus500includes a display panel100, a gate driver200, a data driver300, and a driving circuit substrate400. The display panel100includes pixels P11through Pnm, gate lines GL1through GLn, and data lines DL1through DLm. The display panel100includes a display region DA and a non-display region NDA.

The pixels P11through Pnm are arranged in the display region DA in a matrix form. For example, the pixels P11through Pnm may be disposed in “n” rows and “m” columns crossing each other, in which “m” and “n” are integers greater than 0.

The gate lines GL1through GLn and the data lines DL1through DLm cross each other, and are insulated from each other. The gate lines GL1through GLn are connected to the gate driver200to receive gate signals from the gate driver200. The data lines DL1through DLm are connected to the data driver300to receive analog-type data voltages from the data driver300.

The pixels P11through Pnm are connected to corresponding gate lines GL1through GLn, and to corresponding to the data lines DL1through DLm, respectively. The pixels P11through Pnm receive data voltages through corresponding data lines DL1through DLm, respectively, in response to gate signals transmitted through the gate lines GL1through GLn. The pixels P11through Pnm may display a grayscale corresponding to the data voltages.

The gate driver200generates gate signals, in response to gate control signals transmitted from a timing controller (not shown) mounted on the driving circuit substrate400, and may provide the gate signals to the pixels P11through Pnm in sequence row-by-row through the gate lines GL1through GLn.

The gate driver200may be disposed on the non-display region NDA adjacent to the display region DA. AlthoughFIG. 1illustrates that the gate driver200is disposed on the left side of the display region DA, the gate driver200may be alternatively disposed on the non-display region NDA on the right side or on both sides of the display region DA.

The gate driver200may include gate driving chips (not shown). The gate driving chips may be mounted on the non-display region NDA adjacent to the left side of the display region DA by using a chip on glass (COG) method. The gate driving chips may be alternatively connected to the non-display region NDA adjacent to the display region DA by using a tape carrier package (TCP) method.

The data driver300receives image signals and data control signals from the timing controller (not shown). The data driver300generates analog data voltages corresponding to the image signals in response to the data control signals. The data driver300provides the analog data voltages to the pixels P11through Pnm through the data lines DL1through DLm.

The data driver300may include source driving chips310_1through310_k, in which “k” is an integer greater than 0 and less than m. The source driving chips310_1through310_kare respectively mounted on flexible circuit substrates320_1through320_k, and are connected to the non-display region NDA adjacent to the display region DA through the driving circuit substrate400. AlthoughFIG. 1illustrates that the data driver300is connected to the non-display region NDA adjacent to an upper side of the display region DA, the data driver300may be alternatively connected to the non-display region NDA adjacent to a lower side or both sides of the display region DA through the driving circuit substrate400.

The data driver300may be connected to the display panel100by using a TCP method. Alternatively, the source driving chips310_1through310_kmay be mounted on the non-display region NDA adjacent to the upper side of the display region DA by using a COG method.

Although not shown, the data lines DL1through DLm may be respectively connected to the source driving chips310_1through310_kthrough pad electrodes (not shown) on the non-display region NDA. The gate lines GL1through GLn may be respectively connected to the gate driver200through the pad electrodes (not shown) on the non-display region NDA.

FIG. 2is a cross-sectional view of a pixel of the liquid crystal display apparatus500ofFIG. 1. Referring toFIG. 2, the liquid crystal display apparatus500may include a first substrate110, a second substrate120facing the first substrate110, and a liquid crystal layer130disposed between the first and second substrates110and120.

The first substrate110may be an insulating substrate formed of, for example, glass or plastic. A buffer layer (not shown) may further be disposed on the first substrate110. The buffer layer has a structure, in which an organic material, an inorganic material, or organic and inorganic material are alternately stacked. The buffer layer may facilitate crystallization of a semiconductor, by preventing diffusion of moisture or impurities generated from the first substrate110, or by controlling a velocity of heat transfer when a semiconductor active layer is crystallized while simultaneously blocking moisture or impurities.

A thin-film transistor TFT is disposed on a region of an upper surface of the first substrate110. The thin-film transistor TFT may include a gate electrode141, an active layer142disposed on the gate electrode141, and a first electrode143and a second electrode144spaced apart from each other and disposed on the active layer142. According to the present exemplary embodiment, the first electrode143and the second electrode144may be a source electrode and a drain electrode, respectively.

A gate insulating film145may be disposed between the gate electrode141and the active layer142. According to the present exemplary embodiment, the active layer142may include amorphous silicon, and the gate insulating film145may be a monolayer or a multiple layer including an inorganic material. For example, the gate insulating film145may be a monolayer including silicon nitride (SiNx).

The first and second electrodes143and144may be conductive and disposed on the active layer142. The first and second electrodes143and144may respectively include lower layers143aand144aand upper layers143band144bdisposed on the lower layers143aand144a. The active layer142may include a region between the first electrode143and the second electrode144that are spaced apart from each other, and may function as a channel that electrically connects or disconnects the first electrode143and the second electrode144to each other.

According to the present exemplary embodiment, the lower layers143aand144aof the first and second electrodes143and144may include amorphous silicon, which may be conductive by doping the amorphous silicon with a dopant, for example, n+ amorphous silicon. The lower layers143aand144aof the first and second electrodes143and144may be ohmic contact layers, which may reduce a work function difference between the active layer142and the upper layers143band144b, by being disposed between the active layer142and the upper layers143band144b. The first and second electrodes143and144may directly contact the active layer142, respectively. More particularly, the active layer142and the lower layers143aand144amay directly contact each other, and the lower layers143aand144aand the upper layers143band144bmay directly contact each other.

The upper layers143band144bof the first and second electrodes143and144may include a metal layer, which may include at least one of molybdenum (Mo), aluminum (Al), copper (Cu), and titanium (Ti). The upper layers143band144bmay alternatively be a double layer of Ti/Cu, or a triple layer of Ti/Cu/Ti.

The gate electrode141may be a region protruded from the gate line GLn, and may receive a gate signal from the gate line GLn. The first electrode143may be a region protruded from the data line DLm, and may receive a data signal from the data line DLm. The second electrode144is spaced apart from the first electrode143with the active layer142including a semiconductor material disposed therebetween, and may receive a data signal from the first electrode143when a turn-on signal is applied to the gate electrode141.

A passivation layer151is disposed on the data lines DLm through DLm+1, the source electrode143, and the second electrode144of the thin-film transistor TFT spaced apart from the source electrode143by a gap, above the first substrate110. The passivation layer151may include a first hole that exposes a portion of the drain electrode144of the thin-film transistor TFT.

A first organic layer152is disposed on the thin-film transistor TFT. The first organic layer152is disposed on the passivation layer151. The first organic layer152exposes a portion of the drain electrode144of the thin-film transistor TFT, and includes a second hole corresponding to the first hole of the passivation layer151. The first organic layer152may include a photosensitive organic material.

A reflective layer153is disposed on the first organic layer152. The reflective layer153contacts the drain electrode144of the thin-film transistor TFT, which is exposed through the first hole of the passivation layer151and the second hole of the first organic layer152. The reflective layer153may include a metal having high reflectance, for example, Ag of Ag—Mo (AMO).

A color filter154may be disposed on the reflective layer153. The color filter154includes a third hole corresponding to the first and second holes, and a portion of the drain electrode144of the thin-film transistor TFT is exposed through the first through third holes.

The color filter154may convert incident light to a specific color. For example, the color filter154may be one of a red color filter, a green color filter, and a blue color filter that respectively converts incident light to red light, green light, and blue light. The color filter154may include an organic material, which may include a pigment or a dye of a color to be converted from incident light. The red color filter, the green color filter, and the blue color filter may be sequentially arranged in a length direction of the data lines DL1through DLm and the gate lines GL1through GLn. The arrangement order of the red color filter, the green color filter, and the blue color filter may be varied. When the pixel is a white pixel, the white pixel may be a region that reflects incident light, and thus, a filter that converts the incident light may be omitted.

A second organic layer155may be disposed on the first organic layer152, and cover the reflective layer153and the color filter154. The second organic layer155may include a fourth hole that exposes a portion of the drain electrode144of the thin-film transistor TFT, and corresponds to the second hole of the first organic layer152. The second organic layer155may include a photosensitive organic material.

A pixel electrode156is disposed on the color filter154, and is electrically connected to the thin-film transistor TFT through the first through third holes. The pixel electrode156may include a transparent and conductive material, for example, indium tin oxide (ITO) or indium zinc oxide (IZO).

A first orientation film157may be disposed on the pixel electrode156. The first orientation film157may be disposed between the first substrate110and the liquid crystal layer130. The first orientation film157may include an inorganic material, such as silicon oxide (SiO2), or an organic material, such as polyimide. A rubbing pattern may be included in a surface of the first orientation film157. The rubbing pattern may determine an initial orientation direction of the liquid crystal layer130that contacts the first orientation film157. More particularly, the direction of liquid crystal molecules of the liquid crystal layer130may be determined according to the orientation pattern of the first orientation film157that contacts the liquid crystal layer130.

The second substrate120faces the first substrate110, and a common electrode161may be disposed on the second substrate120and contact each other. The common electrode161may include, for example, ITO or IZO.

A second orientation film162may be disposed on the common electrode161. More particularly, the second orientation film162may be disposed between the second substrate120and the liquid crystal layer130. The second orientation film162may include an inorganic material or an organic material. The inorganic material may be SiO2, and the organic material may be polyimide. A rubbing pattern may be included in a surface of the second orientation film162. The rubbing pattern may determine an initial orientation direction of the liquid crystal layer130that contacts the second orientation film162.

The liquid crystal layer130is disposed between the first substrate110and the second substrate120, and includes liquid crystal molecules (not shown). The liquid crystal molecules of the liquid crystal layer130may display an image by a liquid crystal electrical field applied thereto. The arrangement of the electrodes and the orientation direction of the liquid crystal molecules may vary, depending on a mode of the liquid crystal display apparatus500. The liquid crystal display apparatus500according to the present exemplary embodiment may be in a twisted nematic (TN) mode, however, the liquid crystal display apparatus500may alternatively be in an in plane switching (IPS) mode, a fringe field switching (FFS) mode, or a vertical alignment (VA) mode.

A black matrix171may be disposed between the first substrate110and the second substrate120to prevent color mix between the pixels. The black matrix171may be disposed over the first substrate110, and cover the data lines DL1through DLm and the gate lines GL1through GLn. The black matrix171has a lattice shape having an opening, and a cross-section of a pixel may be determined by the opening. A spacer172is disposed between the first substrate110and the second substrate120facing the first substrate110, and maintains a gap therebetween. The spacer172may be disposed on a location where the black matrix171is disposed between the pixels.

When light enters the liquid crystal display apparatus500, the light is output to the outside through the liquid crystal layer130, after being reflected by the reflective layer153. When light transmits through the liquid crystal layer130, the transmittance of the light is controlled to realize an image. As such, the liquid crystal display apparatus500ofFIG. 2may be referred to as a reflection-type liquid crystal display apparatus.

Since layers are stacked on the first substrate110or the second substrate120of the liquid crystal display apparatus500, a step difference may occur in the pixels or between the pixels. In particular, when the liquid crystal display apparatus500is a reflection-type liquid crystal display apparatus, the liquid crystal display apparatus500may include the reflective layer153and the color filter154, and thus, the step difference may occur in greater degrees. The step difference may cause a rubbing fault in a rubbing process for the orientation of liquid crystal molecules, which may cause light leakage, and thus, may reduce color reproducibility.

In the liquid crystal display apparatus500according to the present exemplary embodiment, in order to prevent the rubbing fault, a length direction Dd of the data lines DL1through DLm may be disposed parallel to an initial orientation direction of the liquid crystal layer130. As used herein, “an initial orientation direction” may be referred to an orientation direction of at least a portion of the liquid crystal molecules included in the liquid crystal layer130, when an electric field is not applied to the liquid crystal layer130. In addition, “parallel” may be referred to being not only mathematically and completely parallel, but also being substantially parallel within an error range.

When the liquid crystal display apparatus500is in a TN mode, the orientation direction of liquid crystal molecules may be changed along a distance between the first substrate110towards the second substrate120. As such, the initial orientation direction in the TN mode may be referred to an initial orientation direction of a portion of the liquid crystal layer130adjacent to the first substrate110, on which the data lines DL1through DLm are disposed. When the liquid crystal display apparatus500is in a VA mode, the initial orientation direction may be referred to an average orientation direction of all liquid crystal molecules or an initial orientation direction of a portion of the liquid crystal layer130adjacent to the first substrate110, on which the data lines DL1through DLm are disposed. Hereinafter, for convenience of description, the initial orientation direction of the liquid crystal layer130will be described as the average orientation direction of liquid crystal molecules adjacent to the first substrate110on which the data lines DL1through DLm are disposed, when an electric field is not applied to the liquid crystal layer130, in order to avoid obscuring exemplary embodiments described herein.

FIG. 3is a drawing showing an arrangement relationship between the lines and the pixels, according to an exemplary embodiment of the present invention.FIG. 4is a drawing showing an RGBW arrangement of the pixels ofFIG. 3.

Referring toFIGS. 3 and 4, a liquid crystal display apparatus may include data lines extending in a first direction, gate lines extending in a second direction crossing the first direction, and pixels respectively connected to the data lines and the gate lines and respectively including the liquid crystal layer130. In the pixels, the data lines may be arranged to be parallel to the initial orientation direction of the liquid crystal layer130. More particularly, the first direction may be parallel to the initial orientation direction of the liquid crystal layer130. Here, the first direction may be referred to as a length direction Dd of the data lines, and the second direction may be referred to as a length direction Gd of the gate lines.

Generally, an initial orientation direction of the liquid crystal layer130may be inclined to a certain degree with respect to the length direction Gd. As such, the length direction Dd of the data lines according to exemplary embodiments of the present invention may be disposed to be inclined with a certain degree with respect to the length direction Gd of the gate lines. For example, if a liquid crystal display apparatus is in a mixed twisted nematic (MTN) mode, the length direction Dd of the data lines may be disposed to be inclined with an inclination angle in a range from 50 degrees to 85 degrees with respect to the length direction Gd of the gate lines. As used herein, the inclination angle may be referred to as an acute angle of angles between the length direction Dd of the data lines and the length direction Gd of the gate lines.

Pixels may be divided by the data lines and the gate lines. The pixels that emit lights of color different from each other may be sequentially arranged in the length direction Gd of the gate lines. For example, first through fourth pixels Pi(j−1), Pij, Pi(j+1), and Pi(j+2) that emit light of different colors may be arranged in the length direction Gd of the gate lines. For example, as illustrated inFIG. 4, the first pixel Pi(j−1) may be a red pixel R that emits red light, the second pixel P(ij) may be a green pixel G that emits green light, the third pixel Pi(j+1) may be a blue pixel B that emits blue light, and the fourth pixel Pi(j+2) may be a white pixel W that transmits incident light without converting the incident light.

As illustrated inFIG. 3, the first through fourth pixels Pi(j−1), P(ij), Pi(j+1), and Pi(j+2) may be sequentially arranged in the length direction Gd of the gate lines. For example, an ithgate line Gi may apply a gate signal to the sequentially arranged first through fourth pixels Pi(j−1), Pij, Pi(j+1), and Pi(j+2).

In the liquid crystal display apparatus according to an exemplary embodiment of the present invention, the data line may apply a data signal to the first through fourth pixels Pi(j−1), Pij, Pi(j+1), and Pi(j+2). Among the data lines, a jthdata line Dj may apply a data signal to sequentially arranged a fifth P(i−1)j, the second pixel Pij, a sixth pixel P(i+1)j, and a seventh pixel P(i+2)j. A portion of a region of the sixth pixel P(i+1)j may overlap a portion of a region of the fourth pixel Pi(j+2) in a perpendicular direction to the length direction Gd of the gate lines. For example, as illustrated inFIG. 4, the fifth pixel P(i−1)j may be a white pixel W that emits white light, the sixth pixel P(i+1)j may be a blue pixel B that emits blue light, and the seventh pixel P(i+2)j may be a red pixel R that emits red light.

Cross-sections of the pixels may have a polygonal shape inclined to a certain direction. For example, a first side of the cross-section of the pixels may be parallel to the length direction Gd of the gate lines, a second side that contacts the first side may be parallel to the length direction Dd of the data lines. The shape of the cross-sections of the pixels may include a parallelogram shape. Cross-sections of a pixel electrode and a filter included in the pixel may have an inclined shape corresponding to the cross-section of the pixel, or a cross-section of the opening of the black matrix may be the same as that of the pixel.

The data lines may alternately apply data signals having polarities different from each other to the pixels by a unit of a data line. For example, when an j−1thdata line Dj−1 and a j+1thdata line Dj+1 apply a positive “+” data signal to the pixels, a jthdata line Dj and a j+2thdata line Dj+2 may apply a negative “−” data signal to the pixels.

Among the pixels that emit the same color light based on a data line, adjacent pixels may be driven by data signals having different polarities from each other. For example, as illustrated inFIG. 4, a data signal applied to a red pixel R+ that is driven by the j−1thdata line D(j−1) may have a different polarity than a data signal applied to a red pixel R− that is driven by the jthdata line Dj. In this manner, when driving polarities of pixels that emit the same color light based on a data line are different, an occurrence of mono-color flicker may be reduced.

FIG. 5is a drawing showing an arrangement relationship between lines and pixels, according to an exemplary embodiment of the present invention. The pixels ofFIG. 5, as compared to the pixel illustrated with reference toFIG. 4, may be configured of a red pixel R, a green pixel G, and a blue pixel B, and may not include a white pixel W configured to transmit incident light, as the incident light is without color conversion.

FIG. 6is a drawing showing an arrangement relationship between lines and pixels, according to an exemplary embodiment of the present invention. The data lines may alternately apply data signals having different polarities from each other to the pixels by a unit of a data line. For example, when the j−1thdata line D(j−1) and the j+1thdata line D(j+1) apply a positive “+” data signal to the pixels, the jthdata line Dj and the j+2thdata line D(j+2) may apply a negative “−” data signal to the pixels. More particularly, the jthdata line Dj may apply a data signal to a white pixel “W−” located on (i−1)j and a blue pixel “B−” located on (i+1)j, and the j+1thdata line D(j+1) neighboring the jthdata line Dj may apply a data signal to a green pixel “G+” located on ij and a red pixel “R+” located on (i+2)j. In this case, a center pixel and adjacent pixel surrounding the center pixel may be applied with data signals having different polarities from each other. In this manner, although a parasitic capacitance may be generated due to misalignment between the pixels, since the variation in the parasite capacity may not be substantially changed, the amount of variation in kick-back may be substantially the same. Accordingly, the generation of a partial residual image may be reduced.

FIG. 7is a drawing showing an arrangement relationship between lines and pixels, according to an exemplary embodiment of the present invention. WhenFIG. 4is compared withFIG. 7, the length direction Dd of the data lines ofFIG. 7may be an opposite direction to the length direction Dd of the data lines ofFIG. 4. The length direction Dd of the data lines ofFIG. 7may be parallel to the initial orientation direction of the liquid crystal layer130included in the pixels. More particularly, the initial orientation direction of the liquid crystal layer130inFIG. 7may be opposite to the initial orientation direction of the liquid crystal layer130inFIG. 4.

It is contemplated that while data lines and an initial orientation direction of the liquid crystal layer130of the liquid crystal display apparatus500having a reflective type have been described above, however, the liquid crystal display apparatus500may also be applied to a transmission-type liquid crystal display apparatus.

In the liquid crystal display apparatus according to exemplary embodiments, since data lines are arranged corresponding to various rubbing directions of liquid crystals, light leakage due to mismatch between liquid crystal molecules and data lines may be reduced. Also, since the data lines are arranged corresponding to rubbing directions, generation disclination of the liquid crystal molecules may be reduced.

Although certain exemplary embodiments and implementations have been described herein, other embodiments and modifications will be apparent from this description. Accordingly, the inventive concept is not limited to such exemplary embodiments, but rather to the broader scope of the presented claims and various obvious modifications and equivalent arrangements.