Liquid crystal composition and display device comprising the same

Abstract

A liquid crystal composition and a display device including the same are provided. A display device according to one embodiment includes a first substrate including a pixel electrode, a second substrate including a common electrode, and a display panel interposed between the first substrate and the second substrate and including a liquid crystal layer, wherein the phase difference of the display panel is 285 nm to 325 nm, and the liquid crystal layer may include a liquid crystal composition having a refractive index anisotropy (Δn) of 0.097 to 0.137, a dielectric anisotropy (Δε) of -3.2 to -2.2, and an elastic modulus (K33) of 13 pN to 17 pN.

Description

Technology Field

[0001] The present invention relates to a liquid crystal composition and a display device including the same. Background Technology

[0002] The importance of display devices is increasing along with the development of multimedia. In response to this, various types of display devices, such as Liquid Crystal Displays (LCDs) and Organic Light Emitting Displays (OLEDs), are being used.

[0003] Among them, a liquid crystal display is one of the most widely used flat panel display devices currently, and includes two substrates on which field generating electrodes, such as pixel electrodes and a common electrode, are formed, and a liquid crystal layer placed between them. The liquid crystal display generates an electric field in the liquid crystal layer by applying voltage to the field generating electrodes, and thereby determines the direction of the liquid crystal molecules in the liquid crystal layer and controls the polarization of incident light to display an image. The problem to be solved

[0004] The problem that the present invention aims to solve is to provide a liquid crystal composition capable of improving response speed.

[0005] Another problem that the present invention aims to solve is to provide a display device with improved response speed.

[0006] The problems of the present invention are not limited to those mentioned above, and other unmentioned technical problems will be clearly understood by those skilled in the art from the description below. means of solving the problem

[0007] A liquid crystal composition according to one embodiment for solving the above problem may comprise, based on 100 parts by weight of the total composition, 20 to 60 parts by weight of at least one compound represented by the following chemical formula 1, 5 to 18 parts by weight of a compound represented by the following chemical formula 2, 5 to 18 parts by weight of a compound represented by the following chemical formula 3, 5 to 35 parts by weight of a compound represented by the following chemical formula 4, 1 to 8 parts by weight of a compound represented by the following chemical formula 5, 1 to 8 parts by weight of a compound represented by the following chemical formula 6, and 1 to 15 parts by weight of a compound represented by the following chemical formula 7.

[0008]

[0009]

[0010]

[0011]

[0012]

[0013]

[0014]

[0015] In the above chemical formulas 1 to 7, R and R' are each independently an alkyl group or an alkenyl group having 1 to 7 carbon atoms, and in the above chemical formula 7, X may be F or O.

[0016] The compound represented by the above chemical formula 1 may include a first compound in which R and R' are alkyl groups, and a second compound in which R is selected from an alkyl group or an alkenyl group and R' is selected from the other one.

[0017] The content of the second compound may be 18 to 36 parts by weight per 100 parts by weight of the total compound represented by Chemical Formula 1.

[0018] It may further include a compound represented by the following chemical formula 8.

[0019]

[0020] The content of the compound represented by the above chemical formula 8 may be 0.2 to 0.5 parts by weight per 100 parts by weight of the total liquid crystal composition.

[0021] The liquid crystal composition may have a refractive index anisotropy (Δn) of 0.097 to 0.137.

[0022] The liquid crystal composition may have a dielectric anisotropy (Δε) of -3.2 to -2.2.

[0023] The liquid crystal composition may have an elastic modulus (K33) of 13 pN to 17 pN.

[0024] Additionally, a display device according to one embodiment includes a first substrate including a pixel electrode, a second substrate including a common electrode, and a display panel interposed between the first substrate and the second substrate and including a liquid crystal layer, wherein the phase difference of the display panel is 285 nm to 325 nm, and the liquid crystal layer may include a liquid crystal composition having a refractive index anisotropy (Δn) of 0.097 to 0.137, a dielectric anisotropy (Δε) of -3.2 to -2.2, and an elastic modulus (K33) of 13 pN to 17 pN.

[0025] The liquid crystal layer above may have a cell gap of 2.0 to 2.6 μm.

[0026] The liquid crystal composition may include a compound represented by the following chemical formula 6.

[0027] [Chemical Formula 6]

[0028]

[0029] In the above chemical formula 6, R and R' are each independently an alkyl group or an alkenyl group having 1 to 7 carbon atoms.

[0030] The compound represented by the above chemical formula 6 may be included in an amount of 1 to 8 parts by weight per 100 parts by weight of the liquid crystal composition.

[0031] The above liquid crystal composition may further include a compound represented by the following chemical formula 7.

[0032] [Chemical Formula 7]

[0033]

[0034] In the above 7, R and R' are each independently an alkyl group or alkenyl group having 1 to 7 carbon atoms, and X is F or O.

[0035] The compound represented by the above chemical formula 7 may be included in an amount of 1 to 15 parts by weight per 100 parts by weight of the liquid crystal composition.

[0036] The liquid crystal composition may further comprise, based on 100 parts by weight of the total liquid crystal composition, 20 to 60 parts by weight of at least one compound represented by the following chemical formula 1, 5 to 18 parts by weight of a compound represented by the following chemical formula 2, 5 to 18 parts by weight of a compound represented by the following chemical formula 3, 5 to 35 parts by weight of a compound represented by the following chemical formula 4, and 1 to 8 parts by weight of a compound represented by the following chemical formula 5.

[0037] [Chemical Formula 1]

[0038]

[0039] [Chemical Formula 2]

[0040]

[0041] [Chemical Formula 3]

[0042]

[0043] [Chemical Formula 4]

[0044]

[0045] [Chemical Formula 5]

[0046]

[0047] In the above chemical formulas 1 to 5, R and R' are each independently an alkyl group or an alkenyl group having 1 to 7 carbon atoms.

[0048] The compound represented by the above chemical formula 1 may include a first compound in which R and R' are alkyl groups, and a second compound in which R is selected from an alkyl group or an alkenyl group and R' is selected from the other one.

[0049] The content of the second compound may be 18 to 36 parts by weight per 100 parts by weight of the total compound represented by Chemical Formula 1.

[0050] The above liquid crystal composition may further include a compound represented by the following chemical formula 8.

[0051] [Chemical Formula 8]

[0052]

[0053] The content of the compound represented by the above chemical formula 8 may be 0.2 to 0.5 parts by weight per 100 parts by weight of the total liquid crystal composition.

[0054] The liquid crystal layer above can have liquid crystals oriented to have a linear angle through a polymer network composed of a polymer of a reactive mesogen represented by the chemical formula 8.

[0055] Specific details of other embodiments are included in the detailed description and drawings. Effects of the invention

[0056] According to a liquid crystal composition according to one embodiment, the refractive index anisotropy (Δn) of the liquid crystal composition can be increased and the dielectric anisotropy (Δε) can be decreased. Accordingly, a display device including a liquid crystal composition according to one embodiment can lower the cell gap of the liquid crystal panel, thereby improving the response speed of the liquid crystal.

[0057] The effects according to the embodiments are not limited to those exemplified above, and a wider variety of effects are included in this specification. Brief explanation of the drawing

[0058] FIG. 1 is a plan view of a display device according to one embodiment. FIG. 2 is a block diagram schematically showing a display device according to one embodiment. FIG. 3 is a schematic perspective view of a display device according to one embodiment. FIG. 4 is a schematic circuit diagram showing an equivalent circuit of a pixel according to one embodiment. FIG. 5 is a plan view schematically showing the planar layout of a pixel according to one embodiment. FIG. 6 is a cross-sectional view schematically showing the structure along the cut line I-I' of FIG. 5. FIGS. 7 to 9 are schematic cross-sectional views showing an enlarged view of area A of FIG. 6. FIG. 10 is an image showing the image when the average response speed per total grayscale of the display device according to the embodiment is 1.8ms. Figure 11 is an image showing a comparative example when the average response speed for each grayscale is 4.6ms. FIG. 12 is a graph showing the response speed of the entire grayscale of the display device according to the embodiment. Figure 13 is a graph showing the response speed of the display device of the comparative example by total grayscale. Specific details for implementing the invention

[0059] The advantages and features of the present invention and the methods for achieving them will become clear by referring to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below but may be implemented in various different forms. These embodiments are provided merely to ensure that the disclosure of the present invention is complete and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims.

[0060] When elements or layers are referred to as being "on" another element or layer, this includes cases where another layer or element is interposed directly on or in the middle of another element. Throughout the specification, the same reference numerals refer to the same components. Shapes, sizes, ratios, angles, numbers, etc., disclosed in the drawings for describing embodiments are examples, and therefore the invention is not limited to the depicted details.

[0061] Specific embodiments will be described below with reference to the attached drawings.

[0062] FIG. 1 is a plan view of a display device according to one embodiment.

[0063] Referring to FIG. 1, a display device (1) according to one embodiment can be applied to various home appliances or Internet of Things devices such as smartphones, mobile phones, tablet PCs, PDAs (Personal Digital Assistants), PMPs (Portable Multimedia Players), televisions, game consoles, wristwatch-type electronic devices, head-mounted displays, monitors of personal computers, laptop computers, car navigation systems, car dashboards, digital cameras, camcorders, external billboards, electronic display boards, medical devices, inspection devices, refrigerators and washing machines, etc. In this specification, a television is described as an example of a display device, and the TV may have high resolution or ultra-high resolution such as HD, UHD, 4K, 8K, etc.

[0064] Additionally, the display device (1) according to some embodiments may include a display panel. For example, it may be a liquid crystal display device (LCD) including a liquid crystal panel. In other embodiments, the display device (1) may be a display device in which the liquid crystal panel is included in an organic light-emitting display device (OLED), an inorganic light-emitting display device (inorganic EL), a quantum dot light-emitting display device (QED), a micro-LED display device (micro-LED), a nano-LED display device (nano-LED), a plasma display device (PDP), a field emission display device (FED), or an electrophoretic display device (EPD) and performs a phase control or polarization control function. For example, the display device (1) may be a stereoscopic image display device in which the liquid crystal panel performs a polarization control function. In the following description, a liquid crystal display device is used as an example of a display device, and unless a special distinction is required, the liquid crystal display device applied to the embodiments will be simply abbreviated as "display device." However, the embodiments are not limited to liquid crystal display devices, and other display devices listed above or known in the art field may be applied within the scope of sharing the technical concept.

[0065] A display device (1) according to one embodiment may have a square shape in a plan view, for example, and may have a rectangular shape. If the display device (1) is a television, it is positioned so that the long side is located in the horizontal direction. However, it is not limited thereto, and the long side may be located in the vertical direction, and it may be installed to be rotatable so that the long side is variably positioned in the horizontal or vertical direction.

[0066] The display device (1) may include a display area (DPA) and a non-display area (NDA). The display area (DPA) may be an active area where an image is displayed. The display area (DPA) may have a rectangular shape in a plan view similar to the overall shape of the display device (1), but is not limited thereto.

[0067] The display area (DPA) may include a plurality of pixels (PX). The plurality of pixels (PX) may be arranged in a matrix direction. The shape of each pixel (PX) may be a rectangle or a square in a planar view, but is not limited thereto, and may be a rhombus shape with each side tilted toward one side direction of the display device (1). The plurality of pixels (PX) may include multiple color pixels (PX). For example, the plurality of pixels (PX) may include a first color pixel (PX) of red, a second color pixel (PX) of green, and a third color pixel (PX) of blue, though is not limited thereto. Each color pixel (PX) may be arranged alternately in a stripe type or a pentile type.

[0068] A non-display area (NDA) may be placed around a display area (DPA). The non-display area (NDA) may surround the display area (DPA) in whole or in part. The display area (DPA) is rectangular in shape, and the non-display area (NDA) may be placed adjacent to the four sides of the display area (DPA). The non-display area (NDA) may form the bezel of the display device (1).

[0069] A driving circuit or driving element for driving a display area (DPA) may be disposed in a non-display area (NDA). In one embodiment, a pad portion is provided on the display substrate of the display device (1) in a first non-display area (NDA) disposed adjacent to the first long side (lower side in FIG. 1) and a second non-display area (NDA) disposed adjacent to the second long side (upper side in FIG. 1), and an external device (EXD) may be mounted on the pad electrode of the pad portion. Examples of the external device (EXD) include a connecting film, a printed circuit board, a driving chip (DIC), a connector, a wiring connecting film, etc. A gate driving portion (20), which is directly formed on the display substrate of the display device (1), may be disposed in a third non-display area (NDA) disposed adjacent to the first short side (left side in FIG. 1).

[0070] FIG. 2 is a block diagram schematically showing a display device according to one embodiment.

[0071] Referring to FIG. 2, the display device (1) may include a display panel (10) that includes a liquid crystal layer between two substrates. The display panel (10) may include liquid crystal cells arranged in a matrix form by an intersection structure of data lines (DL) and gate lines (GL).

[0072] In one embodiment, the display device (1) may include a driving unit (60) that drives the display panel (10). The driving unit (60) changes the driving mode depending on whether the image data (RGB) input from an external system is a video or a still image. For example, if the image data (RGB) is a video, the driving unit (60) is driven in a high-speed driving mode with a high driving frequency, and if the image data (RGB) is a still image, the driving unit (60) is driven in a low-speed driving mode with a low driving frequency. To this end, the driving unit (60) may include a host system (40), a timing controller (50), a data driving unit (30), and a gate driving unit (20).

[0073] The host system (40) receives image data (RGB) from an external system, generates a driving mode signal (MS) corresponding to the image data (RGB), and outputs it to the timing controller (50). Specifically, the host system (40) can generate a driving mode signal (MS) corresponding to the video when the image data (RGB) is a video, and generate a driving mode signal (MS) corresponding to the still image when the image data (RGB) is a still image. The driving mode signal (MS) is a signal that operates in a high-speed mode when the image data (RGB) corresponds to a video, and on the other hand, when the image data (RGB) corresponds to a still image, it may be a signal that operates in a low-speed mode to reduce power consumption.

[0074] The timing controller (50) receives digital video data (RGB) of an input image from the host system (40) and can supply the digital video data (RGB) of the input image to the data driving unit (30). Additionally, the timing controller (50) can receive a driving mode signal (MS) from the host system (40). The timing controller (50) can align the digital video data (RGB) input from the host system (40) according to the arrangement configuration of the pixel array and then supply it to the data driving unit (30).

[0075] The timing controller (50) receives timing signals such as a vertical synchronization signal (Vsync), a horizontal synchronization signal (Hsync), a data enable signal (DE), and a dot clock (CLK) from the host system (40) and can generate control signals to control the operation timing of the data driver (30) and the gate driver (20). The control signals may include a gate timing control signal to control the operation timing of the gate driver (20) and a source timing control signal to control the operation timing of the data driver (30).

[0076] Gate timing control signals may include a Gate Start Pulse (GSP), a Gate Shift Clock (GSC), and a Gate Output Enable (GOE). The Gate Start Pulse (GSP) is applied to an Integrated Circuit (IC) that generates the first gate pulse, thereby controlling the IC to generate the first gate pulse. The Gate Shift Clock (GSC) is a clock signal commonly input to the Integrated Circuits and may be a clock signal for shifting the Gate Start Pulse (GSP). The Gate Output Enable (GOE) can control the outputs of the Integrated Circuits.

[0077] The source timing control signal may include a source start pulse (SSP), a source sampling clock (SSC), a polarity control signal (Polarity: POL), and a source output enable signal (SOE). The source start pulse (SSP) can control the data sampling start timing of the data driver (30). The source sampling clock (SSC) may be a clock signal that controls the data sampling timing in the data driver (30) based on a rising or falling edge. The polarity control signal (POL) can control the polarity of the data voltages sequentially output from each of the data driver ICs. The source output enable signal (SOE) can control the output timing of the data driver (30).

[0078] The timing controller (50) can implement interlaced driving by time-dividing one frame into n (n is a positive integer greater than or equal to 2) subframes and distributing the driving of gate lines (GL) through each subframe. The timing controller (50) can group the gate lines (GL) into n gate groups and assign each of the n gate groups to each of the n subframes according to their driving order.

[0079] The timing controller (50) controls the operation of the gate driver (20) in each subframe to complete sequential scanning of the gate lines (GL) included in the gate group for a period of 1 / n of the 1 subframe period, and generates a buffer operation control signal (LITEST) to cut off the driving power (high-potential driving voltage, base voltage) applied to the buffers of the data driver (30) for a period of (n-1) / n excluding the period of 1 / n during the 1 subframe period. That is, it can control the operation of the data driver (30) to stop during the skip period.

[0080] The data driver (30) may include a shift register, a latch array, a digital-to-analog converter, an output circuit, etc. The data driver (30) may latch digital video data (RGB) according to a source timing control signal, convert the latched data into an analog positive / negative gamma compensation voltage, and supply data voltages with polarity inverted at a predetermined period to data lines (DL) through a plurality of output channels. The output circuit includes a plurality of buffer units. The buffer units are connected to the output channels, and each output channel can be connected one-to-one to the data lines (DL). For example, the data driver (30) may control the polarity of the data voltages output to the output channels using a column inversion method to reduce power consumption. According to the column inversion method, the polarity of the data voltage output from the same output channel may be inverted on a sub-frame basis. Also, the polarity of the data voltages output from adjacent output channels may be opposite to each other.

[0081] The gate driver (20) can supply gate pulses to gate lines (GL) in the aforementioned interlaced driving method according to gate timing control signals using a shift register and a level shifter. The data driver (30) and the gate driver (20) can be mounted according to the COG (chip on glass) or COF (chip on film) method. Additionally, the gate driver (20) can be formed directly on a substrate. In one embodiment, the gate driver (20) being formed on a substrate will be described as an example.

[0082] FIG. 3 is a schematic perspective view of a display device according to one embodiment.

[0083] Referring to FIG. 3, a display device according to one embodiment may include a first substrate (100), a second substrate (200) facing the first substrate (100), and a liquid crystal layer (300) interposed between the first substrate (100) and the second substrate (200). The liquid crystal layer (300) includes a plurality of liquid crystals (LC), and the liquid crystals (LC) may have negative dielectric anisotropy.

[0084] A display device according to one embodiment may include a display area (DPA) and a non-display area (NDA). The display area (DPA) includes a plurality of pixels (PX). Each pixel (PX) may display one of the basic colors to implement color display. A gate line (GL) is arranged to extend in a first direction (DR1), and a data line (DL) is arranged to extend in a second direction (DR2), so as to transmit a gate driving signal and a data driving signal to each of the plurality of pixels (PX).

[0085] The liquid crystal cells of the pixels (PX) display an image of video data by adjusting the amount of light transmitted by the electric field difference between the data voltage applied to the pixel electrode and the common voltage applied to the common electrode. The common electrode is formed on a color filter array substrate in a vertical electric field driving method such as TN (Twisted Nematic) mode and VA (Vertical Alignment) mode, and is formed together with the pixel electrode on a first substrate (100), for example, a thin film transistor array substrate, in a horizontal electric field driving method such as IPS (In Plane Switching) mode and PLS (Plane to Line Switching) mode.

[0086] The first substrate (100) includes data lines (DL), gate lines (GL), thin-film transistors, pixel electrodes connected 1:1 to the thin-film transistors, and a storage capacitor (Cst) not shown connected 1:1 to the pixel electrodes. A black matrix and a color filter may be disposed on the second substrate (200). In another embodiment, the color filter may be disposed on the first substrate (100). A polarizer may be attached to each of the first substrate (100) and the second substrate (200), and an alignment layer for setting the pre-tilt angle of the liquid crystal may be disposed.

[0087] As an example applicable to one embodiment, the display device can be implemented in any liquid crystal mode, as well as TN mode, VA mode, IPS mode, and PLS mode.

[0088] FIG. 4 is a schematic circuit diagram showing an equivalent circuit of a pixel according to one embodiment, FIG. 5 is a schematic diagram showing a planar layout of a pixel according to one embodiment, FIG. 6 is a schematic diagram showing a cross-sectional structure along the cut line I-I' of FIG. 5, and FIG. 7 to 9 are schematic diagrams showing an enlarged view of area A of FIG. 6.

[0089] Referring to FIG. 4, a display device of one embodiment converts digital video data into an analog data voltage based on a gamma reference voltage and supplies it to a data line (DL), while simultaneously supplying a scan pulse to a gate line (GL) to charge the data voltage to a liquid crystal cell (Clc). To this end, the gate electrode of a thin-film transistor (TFT) is connected to the gate line (GL), the source electrode is connected to the data line (DL), and the drain electrode of the thin-film transistor (TFT) is connected to the pixel electrode of the liquid crystal cell (Clc) and one electrode of a storage capacitor (Cst).

[0090] A common voltage (Vcom) is supplied to the common electrode of the liquid crystal cell (Clc). The storage capacitor (Cst) charges the data voltage applied from the data line (DL) when the thin-film transistor is turned on, thereby maintaining the voltage of the liquid crystal cell (Clc) constant. When a scan pulse is applied to the gate line (GL), the thin-film transistor is turned on to form a channel between the source electrode and the drain electrode, supplying the voltage on the data line (DL) to the pixel electrode of the liquid crystal cell (Clc). At this time, the liquid crystal molecules of the liquid crystal cell (Clc) change their arrangement due to the electric field between the pixel electrode and the common electrode, thereby varying the incident light. A display device of one embodiment can be operated based on this principle.

[0091] Specifically, referring to FIGS. 5 and 6, the first substrate (100) is a substrate on which a switching element (120) for controlling the orientation direction of the liquid crystal (LC) within the liquid crystal layer (300) is disposed, and the second substrate (200) may be a counter substrate for sealing the liquid crystal layer (300) together with the first substrate (100).

[0092] The first substrate (100) may include a first insulating substrate (110), a switching element (120) disposed on the first insulating substrate (110), and a pixel electrode (150) disposed on the switching element (120).

[0093] The first insulating substrate (110) may be a transparent insulating substrate. For example, the first insulating substrate (110) may be a glass or plastic substrate. Additionally, the first insulating substrate (110) may be flexible.

[0094] A switching element (120) may be disposed on the first insulating substrate (110). The switching element (120) may be a thin-film transistor comprising a gate electrode (121) disposed on the first insulating substrate (110), a semiconductor layer (122) disposed on the gate electrode (121), and a source electrode (123) and a drain electrode (124) disposed spaced apart from each other on the semiconductor layer (122).

[0095] The gate electrode (121) is connected to the gate line (GL) to transmit a gate driving signal. The gate electrode (121) is formed from any one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. Additionally, the gate electrode (121) may be a multilayer formed from any one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. For example, the gate electrode (121) may be a double layer of molybdenum / aluminum-neodymium or molybdenum / aluminum.

[0096] A gate insulating film (131) that insulates the gate electrode (121) may be disposed on the gate electrode (121). The gate insulating film (131) may be made of silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy), and may be a single layer or a multilayer thereof.

[0097] A semiconductor layer (122) may be disposed on a gate insulating film (131). The semiconductor layer (122) may overlap with the gate electrode (121) on the gate insulating film (131). The semiconductor layer (122) may be made of a silicon semiconductor or an oxide semiconductor. The silicon semiconductor may include amorphous silicon or crystallized polycrystalline silicon. Here, polycrystalline silicon has high mobility (100 cm² / Vs or more), so it may have low energy consumption and excellent reliability, and oxide semiconductors have low off-current, so they may be selectively used as needed in this embodiment.

[0098] Source electrodes (123) and drain electrodes (124) spaced apart from each other may be disposed on the semiconductor layer (122). The source electrode (123) may be connected to a data line (DL) to transmit a data driving signal, and the drain electrode (124) may be electrically connected to a pixel electrode (150).

[0099] The source electrode (123) and the drain electrode (124) may be made of a single layer or multiple layers. If the source electrode (123) and the drain electrode (124) are single layers, they may be made of any one selected from the group consisting of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu), or an alloy thereof. Additionally, if the source electrode (123) and the drain electrode (124) are multiple layers, they may be made of two layers of copper / titanium or molybdenum / aluminum-neodymium, or three layers of titanium / aluminum / titanium, molybdenum / aluminum / molybdenum, or molybdenum / aluminum-neodymium / molybdenum.

[0100] A protective film (133) capable of protecting the switching element (120) may be disposed on the aforementioned switching element (120). The protective film (133) may be made of an inorganic material, an organic material, or a mixture thereof. If the protective film (133) is an inorganic material, it may be made of a single layer of silicon oxide (SiOx), silicon nitride (SiNx), or silicon oxynitride (SiOxNy) or a multilayer thereof. If the protective film (133) is an organic material, it may be made of an organic material such as polyimide, benzocyclobutene series resin, or acrylate series resin. If the protective film (133) is a mixture of inorganic and organic materials, the organic material may be disposed on the inorganic material to flatten the step difference at the bottom.

[0101] A pixel electrode (150) may be placed on the protective film (133). The pixel electrode (150) may be connected to a drain electrode (124) through a contact hole (140) and controlled by a data driving signal.

[0102] The pixel electrode (150) may include a first stem portion (151), a plurality of branch portions (152) that extend outward from the stem portion (151) and are spaced apart from each other with a slit (153) in between, and an extension portion (154) that extends to a switching element (120).

[0103] The stem portion (151) may include a horizontal stem portion extending in a first direction (DR1) and a vertical stem portion extending in a second direction (DR2). The stem portion (151) may divide the pixel electrode (150) into sub-regions, i.e., domains. The stem portion (151) may be formed in a cross shape, for example. In this case, the pixel electrode (150) may be divided into four sub-regions by the stem portion (151). The branch portions (152) located in each of the sub-regions may have different directions of extension. For example, as shown in FIG. 2, the branch portion (152) located in the sub-region in the upper right direction may extend obliquely from the stem portion (151) in the upper right direction, and the branch portion (152) located in the sub-region in the lower right direction may extend obliquely from the stem portion (151) in the lower right direction. Additionally, the branch portion (152) located in the upper left direction of the sub-region may be extended obliquely from the stem portion (151) in the upper left direction, and the branch portion (152) located in the lower left direction of the sub-region may be extended obliquely from the stem portion (151) in the lower left direction. The extension portion (154) may be extended from the stem portion (151) or the branch portion (152) to the switching element (120) and connected to the drain electrode (124) through the contact hole (140).

[0104] The pixel electrode (150) may include a transparent conductive material through which light can pass. The pixel electrode (150) may be made of indium tin oxide (ITO), indium zinc oxide (IZO), or indium tin zinc oxide (ITZO), but is not limited thereto, and any material that is transparent and conductive may be used.

[0105] A first alignment layer (160) may be disposed on the pixel electrode (150). The first alignment layer (160) may include a vertical alignment element, and the vertical alignment element may induce initial vertical alignment of the liquid crystals (LC) within the liquid crystal layer (300). The first alignment layer (160) may include polyamic acid or polyimide.

[0106] Meanwhile, the second substrate (200) may include a second insulating substrate (210), a light-blocking member (220) disposed on the second insulating substrate (210), a color filter (230), and a common electrode (250) disposed on the light-blocking member (220) and the color filter (230).

[0107] The second insulating substrate (210) may be a transparent insulating substrate such as the first insulating substrate (110). The light-blocking member (220) may be made of a material that blocks the transmission of light by absorbing or reflecting light of at least a specific wavelength band. For example, the light-blocking member (220) may be a black matrix. The light-blocking member (220) may be placed at the boundary between adjacent pixels to prevent color mixing defects.

[0108] The color filter (230) may be made of a material that absorbs a specific wavelength band of transmitted light or shifts or converts the wavelength of transmitted light to a specific wavelength. That is, the color filter (230) can selectively transmit only light of a specific wavelength band. FIG. 3 illustrates a light-blocking member (220) and a color filter (230) disposed on a second substrate (200), but one or more of the light-blocking member (220) and the color filter (230) may be disposed on a first substrate (100).

[0109] An overcoat layer (240) may be disposed on the light-blocking member (220) and the color filter (230). The overcoat layer (240) may be made of an organic material. The overcoat layer (240) may flatten the step difference caused by the components laminated on the second substrate (210).

[0110] A common electrode (250) may be disposed on an overcoat layer (240). The common electrode (250) may be disposed on a plurality of pixels to apply a common voltage. The common electrode (250) may form a vertical electric field in the liquid crystal layer (300) together with the pixel electrode (150). The common electrode (250) may control the orientation direction of the liquid crystal (LC) by forming an electric field in the liquid crystal layer (300) together with the pixel electrode (150). FIG. 6 illustrates a case where the pixel electrode (150) is disposed on a first substrate (100) and the common electrode (250) is disposed on a second substrate (200), but the pixel electrode (150) and the common electrode (250) may be disposed on the same substrate.

[0111] A second alignment layer (260) may be disposed on the common electrode (250). Since the second alignment layer (260) is configured identically to the first alignment layer (160), redundant descriptions are omitted.

[0112] A liquid crystal layer (300) may be disposed between the first substrate (100) and the second substrate (200). The liquid crystal layer (300) may include a plurality of liquid crystals (LC). The liquid crystal composition forming the liquid crystal layer (300) may have negative dielectric anisotropy. The liquid crystal (LC) may maintain a stabilized state in which its long axis is oriented in a direction approximately perpendicular to the orientation surface in an initial orientation state. Additionally, the liquid crystal (LC) may maintain a stabilized state with a predetermined line inclination angle.

[0113] A liquid crystal (LC) having negative permittivity anisotropy can be tilted such that its long axis forms a predetermined angle with respect to the direction of the electric field by the vertical electric field formed by the pixel electrode (150) and the common electrode (250). As the direction of the long axis of the liquid crystal (LC) changes, the phase difference delay value changes, and accordingly, the amount of light transmitted through the liquid crystal layer (300) can be controlled. In the embodiment, the initial orientation state refers to the orientation state of the liquid crystal (LC) when no electric field is formed in the liquid crystal layer (300).

[0114] Referring to FIGS. 7 to 9, a display device according to one embodiment may have a liquid crystal layer (300) that is polymer stabilized vertically aligned (PS-VA). The liquid crystal layer (300) that is polymer stabilized vertically aligned may be stabilized by aligning the liquid crystal (LC) to have a linear gradient through a polymer network composed of polymers of reactive mesogens (RM).

[0115] A liquid crystal layer (300) according to one embodiment may include a liquid crystal (LC) and a reactive mesogen (RM). The reactive mesogen (RM) may form a polymer network composed of polymers of reactive mesogens (RM) through a UV exposure process.

[0116] Specifically, as shown in FIG. 7, the liquid crystal layer (300) may have liquid crystal (LC) and reactive mesogen (RM) arranged in a disordered manner in the initial state.

[0117] As illustrated in FIG. 8, when an electric field is formed in the liquid crystal layer (300), the liquid crystals (LC) can be tilted in a direction parallel to the length direction of the branch portion (152 in FIG. 5) of the pixel electrode (150 in FIG. 5) in response to the electric field. In FIG. 5, the pixel electrode (150) is formed to have four domains, so that the direction in which the liquid crystals (LC) tilt in one pixel can be a total of four directions. When UV is irradiated while an electric field is applied to the liquid crystal layer (300), the reactive mesogen (RM) undergoes a polymerization reaction to form a polymer network (RMN) composed of polymers in contact with the aforementioned first alignment layer (160) and second alignment layer (260). The liquid crystals (LC) have a pre-tilt in the aforementioned direction determined by the polymer network (RMN).

[0118] As shown in FIG. 9, the liquid crystal layer (300) can be manufactured by irradiating fluorescent UV to finally exhaust the unreacted residual reactive mesogens (RM) within the liquid crystal layer (300).

[0119] The above-described liquid crystal layer (300) can improve the response speed of the liquid crystal (LC) by using a reactive mesogen (RM). In one embodiment, a liquid crystal composition capable of further improving the response speed of the liquid crystal (LC) will be described below.

[0120] A liquid crystal composition constituting a liquid crystal layer (300) according to one embodiment may include a neutral compound and a polar compound containing at least one fluorine atom.

[0121] Neutral compounds may include compounds represented by the following chemical formulas 1 to 3.

[0122] [Chemical Formula 1]

[0123]

[0124] [Chemical Formula 2]

[0125]

[0126] [Chemical Formula 3]

[0127]

[0128] In the above chemical formulas 1 to 3, R and R' may each independently be an alkyl group or an alkenyl group having 1 to 7 carbon atoms.

[0129] Specifically, each of chemical formulas 1 to 3 may include an alkyl group or an alkenyl group. Where both R and R' are alkyl groups or both are alkenyl groups, the alkyl groups or alkenyl groups may be the same or different from each other. The alkyl groups or alkenyl groups may each have the same number of carbon atoms or different numbers of carbon atoms.

[0130] The compound represented by Chemical Formula 1 may be included in an amount of 20 to 60 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 1 is included in an amount of 20 to 60 parts by weight per 100 parts by weight of the total liquid crystal composition, the stability of the liquid crystal can be improved.

[0131] In particular, the compound represented by Formula 1 may comprise at least two compounds. Specifically, the compound represented by Formula 1 may comprise a first compound in which at least one of R and R' comprises an alkyl group, and a second compound in which at least one of R and R' comprises an alkenyl group. In the first compound, R and R' may be alkyl groups, and in the second compound, R may be selected from an alkyl group or an alkenyl group, and R' may be selected from the other. In one embodiment, in the first compound, R and R' may be non-polar and may be alkyl groups. In the second compound, R (or R') may be an alkyl group and R' (or R) may be an alkenyl group.

[0132] The first compound may be a neutral compound, and the second compound may be a low viscosity compound. In this case, the second compound may be included in an amount of 18 to 36 parts by weight with respect to 100 parts by weight of the total compound represented by Formula 1, and the remaining amount may be the first compound. When the second compound is included in an amount of 18 to 36 parts by weight with respect to the compound represented by Formula 1, the viscosity of the liquid crystal composition can be appropriately controlled.

[0133] The compound represented by Chemical Formula 2 may be included in an amount of 5 to 18 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 2 is included in an amount of 5 to 8 parts by weight per 100 parts by weight of the total liquid crystal composition, the refractive index anisotropy (Δn), nematic phase-isotropic transition temperature (Tni), rotational viscosity (γ1), and elastic modulus (K11, K33) can be improved.

[0134] The compound represented by Chemical Formula 3 may be included in an amount of 5 to 18 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 3 is included in an amount of 5 to 18 parts by weight per 100 parts by weight of the total liquid crystal composition, the refractive index anisotropy (Δn), nematic phase-isotropic transition temperature (Tni), rotational viscosity (γ1), and elastic modulus (K11, K33) can be improved.

[0135] The compounds represented by the aforementioned chemical formulas 1 to 3 are neutral compounds, and each of them can improve the stability of the liquid crystal.

[0136] Meanwhile, polar compounds may include compounds represented by the following chemical formulas 4 to 7.

[0137] [Chemical Formula 4]

[0138]

[0139] [Chemical Formula 5]

[0140]

[0141] [Chemical Formula 6]

[0142]

[0143] [Chemical Formula 7]

[0144]

[0145] In the above chemical formulas 4 to 7, R and R' may each independently be an alkyl group or an alkenyl group having 1 to 7 carbon atoms. In the above chemical formula 7, X may be F or O.

[0146] Specifically, each of formulas 4 to 7 may include an alkyl group or an alkenyl group. Where R and R' are both alkyl groups or both alkenyl groups, the alkyl groups or alkenyl groups may be the same or different from each other. The alkyl groups or alkenyl groups may each have the same number of carbon atoms or different numbers of carbon atoms.

[0147] The compound represented by Chemical Formula 4 may be included in an amount of 5 to 35 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 4 is included in an amount of 5 to 35 parts by weight per 100 parts by weight of the total liquid crystal composition, the refractive index anisotropy (Δn), elastic modulus (K11, K33), and dielectric constant can be improved.

[0148] The compound represented by Chemical Formula 5 may be included in an amount of 1 to 8 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 5 is included in an amount of 1 to 8 parts by weight per 100 parts by weight of the liquid crystal composition, the refractive index anisotropy (Δn), nematic phase-isotropic transition temperature (Tni), rotational viscosity (γ1), and elastic modulus (K11, K33) can be improved.

[0149] The compound represented by Chemical Formula 6 may be included in an amount of 1 to 8 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 6 is included in an amount of 1 to 8 parts by weight per 100 parts by weight of the total liquid crystal composition, the refractive index anisotropy (Δn) and elastic modulus (K11, K33) can be improved and the viscosity can be lowered.

[0150] The compound represented by Chemical Formula 7 may be included in an amount of 1 to 15 parts by weight per 100 parts by weight of the total liquid crystal composition. When the compound represented by Chemical Formula 7 is included in an amount of 1 to 15 parts by weight per 100 parts by weight of the total liquid crystal composition, the refractive index anisotropy (Δn), dielectric constant, nematic phase-isotropic transition temperature (Tni), rotational viscosity (γ1), and elastic modulus (K11, K33) can be improved.

[0151] The compounds represented by the aforementioned chemical formulas 4 to 7 are polar compounds, each of which can improve the refractive index anisotropy (Δn) and elastic modulus (K11, K33) of the liquid crystal.

[0152] Meanwhile, the liquid crystal composition according to one embodiment may further include a compound represented by the following chemical formula 8.

[0153] [Chemical Formula 8]

[0154]

[0155] The compound represented by chemical formula 8 is a type of reactive mesogen and may contain methacrylates with many reaction sites.

[0156] The compound represented by Chemical Formula 8 may be included in an amount of 0.2 to 0.5 parts by weight per 100 parts by weight of the total liquid crystal composition. The compound represented by Chemical Formula 8 may form a polymer network composed of polymers through a UV irradiation process. Here, the compound represented by Chemical Formula 8 may form a polymer network or may remain in the liquid crystal layer (300) without forming a polymer network.

[0157] A liquid crystal composition according to one embodiment may include compounds represented by the aforementioned chemical formulas 1 to 7, respectively. In particular, it may include 20 to 60 parts by weight of a compound represented by chemical formula 1, 5 to 18 parts by weight of a compound represented by chemical formula 2, 5 to 18 parts by weight of a compound represented by chemical formula 3, 5 to 35 parts by weight of a compound represented by chemical formula 4, 1 to 8 parts by weight of a compound represented by chemical formula 5, 1 to 8 parts by weight of a compound represented by chemical formula 6, and 1 to 15 parts by weight of a compound represented by chemical formula 7.

[0158] The liquid crystal composition according to the above-described embodiment may have a low viscosity rotational viscosity (γ1) of 81 mPa·s or less by including a compound of Formula 7 that exhibits relatively high polarity. Additionally, the liquid crystal composition may secure an elastic modulus (K33) without viscosity increase by including compounds of Formulas 2, 3, 5, and 6 that include three rings. For example, the liquid crystal composition may have an elastic modulus (K33) of 13 to 17 pN. Furthermore, the liquid crystal composition may form a cell gap (d) of the liquid crystal panel of 2.0 to 2.6 μm to improve yield and reduce transmittance.

[0159] A liquid crystal composition according to one embodiment can improve response speed by relatively lowering the cell gap (d) as the refractive index anisotropy (Δn) increases. A liquid crystal composition according to one embodiment may have a refractive index anisotropy (Δn) of 0.097 to 0.137 and a dielectric anisotropy (Δε) of -3.2 to -2.2. Additionally, the liquid crystal composition may have an elastic modulus (K33) of 13 to 17 pN. Within the phase difference range of the liquid crystal panel, the liquid crystal composition may be adjusted so that the refractive index anisotropy (Δn) has a value corresponding to the cell gap (d), or conversely, so that the cell gap (d) has a value corresponding to the refractive index anisotropy (Δn). In one embodiment, the phase difference of the liquid crystal panel may be adjusted to have a range of 285 to 325 nm.

[0160] The liquid crystal composition described above can lower the cell gap (d) of the liquid crystal panel by exhibiting high refractive index anisotropy (Δn) and low dielectric anisotropy (Δε). Accordingly, the response speed of the liquid crystal in the liquid crystal panel can be improved.

[0161] Hereinafter, we will examine the transmittance characteristics of a display device including a liquid crystal composition according to the above-described embodiment. Below, we will manufacture the display device shown in FIGS. 5 and FIGS. 6 and disclose an example of the liquid crystal composition disclosed below.

[0162] <Example>

[0163] Using the liquid crystal composition of Table 1 below, a display device illustrated in FIGS. 5 and FIGS. 6 described above was manufactured, and a 27-inch QHD display device was manufactured.

[0164] compound Content (parts by weight) 28.5 9.0 11.5 11.0 20.5 5.0 5.5 9.0

[0165] The nematic phase-isotropic transition temperature (Tni), refractive index anisotropy (Δn), dielectric anisotropy (Δε), rotational viscosity (γ1), and elastic modulus (K11, K33) of the liquid crystal composition prepared according to the above-described example were measured and are shown in Table 2 below.

[0166] Examples Nematic phase-isotropic transition temperature (Tni) 74 Refractive index anisotropy (Δn) 0.117 Permittivity anisotropy (Δε) -2.7 Rotational viscosity (γ1) 75 Elastic modulus (K11) 14 Elastic modulus (K33) 15

[0167] Referring to Table 2 above, the liquid crystal composition according to the example showed a nematic phase-isotropic transition temperature (Tni) of 74°C, a refractive index anisotropy (Δn) of 0.117, a dielectric anisotropy (Δε) of -2.7, a rotational viscosity (γ1) of 75, an elastic modulus (K11) of 14, and an elastic modulus (K33) of 15.

[0168] The transmittance and average response speed for each total grayscale of the display device according to the above-described embodiment were measured and are shown in Table 3 below. At this time, the cell gap (d) of the display device was manufactured to be 2.6 μm.

[0169] Examples Transmittance (%) 3.1 Average response speed per overall grayscale level Overdrive enabled 1.8ms Overdrive not running 5.6ms

[0170] Referring to Table 3, the display device according to the embodiment showed a transmittance of 3.1%, and the average response speed per gradation during overdrive driving was 1.8ms.

[0171] In one embodiment, the same image was displayed on a display device having an average response speed of 1.8ms per grayscale manufactured according to the above embodiment, and on a display device having an average response speed of 4.6ms per grayscale as a comparative example, and then the image was scrolled from left to right and the presence of afterimage was observed.

[0172] FIG. 10 is an image showing a display device according to an embodiment, and FIG. 11 is an image showing a display device of a comparative example.

[0173] As shown in FIGS. 10 and 11, compared to the display device of the comparative example, it was confirmed that the display device according to the embodiment had relatively improved afterimage when scrolling images.

[0174] In one embodiment, the response time according to driving (Ton) and driving stop (Toff) for each of the following was measured for a display device having an average response speed of 1.8ms per overall grayscale manufactured according to the above-described embodiment, and a display device having an average response speed of 4.6ms per overall grayscale as a comparative example.

[0175] FIG. 12 is a graph showing the response speed of a display device manufactured according to an embodiment, measured across all grayscale levels, and FIG. 13 is a graph showing the response speed of a display device of a comparative example, measured across all grayscale levels.

[0176] As shown in FIGS. 12 and 13, it was confirmed that the display device according to the embodiment had a significantly faster response speed for each grayscale level compared to the comparative example.

[0177] As described above, the liquid crystal composition according to one embodiment can increase the refractive index anisotropy (Δn) and decrease the dielectric anisotropy (Δε) of the liquid crystal composition. A display device including the liquid crystal composition according to one embodiment can lower the cell gap of the liquid crystal panel, thereby improving the response speed of the liquid crystal.

[0178] Although embodiments of the present invention have been described above with reference to the attached drawings, those skilled in the art will understand that the present invention may be implemented in other specific forms without changing the technical concept or essential features thereof. Therefore, the embodiments described above should be understood as illustrative in all respects and not restrictive. Explanation of the symbols

[0179] 150: Pixel electrode 160: First alignment layer 250: Common electrode 260: Second alignment layer LC: Liquid Crystal RM: Reactive Mesogen

Claims

Claim 1 A liquid crystal composition comprising, based on 100 parts by weight of the total composition, 20 to 60 parts by weight of at least one compound represented by the following Chemical Formula 1; 5 to 18 parts by weight of a compound represented by the following Chemical Formula 2; 5 to 18 parts by weight of a compound represented by the following Chemical Formula 3; 5 to 35 parts by weight of a compound represented by the following Chemical Formula 4; 1 to 8 parts by weight of a compound represented by the following Chemical Formula 5; 1 to 8 parts by weight of a compound represented by the following Chemical Formula 6; and 1 to 15 parts by weight of a compound represented by the following Chemical Formula 7, wherein the refractive index anisotropy (Δn) is 0.097 to 0.137, the nematic phase-isotropic transition temperature is 74 degrees, and the rotational viscosity is 75. [Chemical Formula 1] [Chemical Formula 2] [Chemical Formula 3] [Chemical Formula 4] [Chemical Formula 5] [Chemical Formula 6] [Chemical Formula 7] In the above chemical formulas 1 to 6, R and R' are each independently an alkyl group having 1 to 7 carbon atoms or an alkenyl group having 2 to 7 carbon atoms, and in the above chemical formula 7, R and R' are alkenyl groups having 2 to 7 carbon atoms and X is O. Claim 2 The liquid crystal composition according to claim 1, wherein the compound represented by Chemical Formula 1 comprises a first compound in which R and R' are alkyl groups, and a second compound in which R is selected from an alkyl group or an alkenyl group and R' is selected from the other one. Claim 3 A liquid crystal composition according to claim 2, wherein the content of the second compound is 18 to 36 parts by weight per 100 parts by weight of the total compound represented by Chemical Formula 1. Claim 4 A liquid crystal composition according to claim 1, further comprising a compound represented by the following chemical formula 8. [Chemical Formula 8] Claim 5 A liquid crystal composition according to claim 4, wherein the content of the compound represented by the chemical formula 8 is 0.2 to 0.5 parts by weight per 100 parts by weight of the total liquid crystal composition. Claim 6 In claim 1, the liquid crystal composition is a liquid crystal composition having a refractive index anisotropy (Δn) of 0.097 to 0.

137. Claim 7 In claim 1, the liquid crystal composition is a liquid crystal composition having a dielectric anisotropy (Δε) of -3.2 to -2.

2. Claim 8 In claim 1, the liquid crystal composition is a liquid crystal composition having an elastic modulus (K33) of 13 pN to 17 pN. Claim 9 A display device comprising: a first substrate including a pixel electrode; a second substrate including a common electrode; and a display panel interposed between the first substrate and the second substrate and including a liquid crystal layer, wherein the phase difference of the display panel is 285 nm to 325 nm, and the liquid crystal layer has a refractive index anisotropy (Δn) of 0.097 to 0.137, a dielectric anisotropy (Δε) of -3.2 to -2.2, an elastic modulus (K33) of 13 pN to 17 pN, a nematic phase-isotropic transition temperature of 74 degrees, and a rotational viscosity of 75, wherein the liquid crystal composition comprises a compound represented by the following chemical formula 7. [Chemical Formula 7] In the above chemical formula 7, R and R' are alkenyl groups having 2 to 7 carbon atoms, and X is O. Claim 10 In claim 9, the liquid crystal layer is a display device having a cell gap of 2.0 to 2.6 μm. Claim 11 In claim 9, the liquid crystal composition is a display device comprising a compound represented by the following chemical formula 6. [Chemical Formula 6] In the above chemical formula 6, R and R' are each independently an alkyl group having 1 to 7 carbon atoms or an alkenyl group having 2 to 7 carbon atoms. Claim 12 A display device according to claim 11, wherein the compound represented by the chemical formula 6 is included in an amount of 1 to 8 parts by weight per 100 parts by weight of the liquid crystal composition. Claim 13 delete Claim 14 A display device according to claim 9, wherein the compound represented by the chemical formula 7 is included in an amount of 1 to 15 parts by weight per 100 parts by weight of the liquid crystal composition. Claim 15 A display device according to claim 9, wherein the liquid crystal composition further comprises, based on 100 parts by weight of the total liquid crystal composition, 20 to 60 parts by weight of at least one compound represented by the following chemical formula 1; 5 to 18 parts by weight of a compound represented by the following chemical formula 2; 5 to 18 parts by weight of a compound represented by the following chemical formula 3; 5 to 35 parts by weight of a compound represented by the following chemical formula 4; and 1 to 8 parts by weight of a compound represented by the following chemical formula 5. [Chemical Formula 1] [Chemical Formula 2] [Chemical Formula 3] [Chemical Formula 4] [Chemical Formula 5] In the above chemical formulas 1 to 5, R and R' are each independently an alkyl group having 1 to 7 carbon atoms or an alkenyl group having 2 to 7 carbon atoms. Claim 16 In claim 15, the compound represented by the above chemical formula 1 comprises a first compound in which R and R' are alkyl groups, and a second compound in which R is selected from an alkyl group or an alkenyl group and R' is selected from the other one. Claim 17 A display device according to claim 16, wherein the content of the second compound is 18 to 36 parts by weight per 100 parts by weight of the total compound represented by the chemical formula 1. Claim 18 In claim 15, the liquid crystal composition further comprises a compound represented by the following chemical formula 8 in a display device. [Chemical Formula 8] Claim 19 A display device according to claim 18, wherein the content of the compound represented by the chemical formula 8 is 0.2 to 0.5 parts by weight per 100 parts by weight of the total liquid crystal composition. Claim 20 In claim 18, the liquid crystal layer is a display device in which the liquid crystal is oriented to have a linear angle of inclination through a polymer network composed of a polymer of a reactive mesogen represented by the chemical formula 8.

Images