Liquid crystal display device

Abstract

This disclosure provides a liquid crystal display device with high display quality. [Solution] The liquid crystal display device has a plurality of pixels arranged in a matrix including a plurality of rows and a plurality of columns, and comprises a first substrate, a liquid crystal layer, and a second substrate in order from the back side toward the observation surface side, wherein the first substrate has a first electrode, an insulating layer, and a second electrode, each of which has one longitudinal opening extending along the row or column direction of the plurality of pixels, and further comprises a plurality of nonlinear elements arranged corresponding to each pixel, and the liquid crystal layer contains liquid crystal molecules and a chiral dopant, and in a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state without applied voltage is arranged parallel to or perpendicular to the longitudinal direction of the opening.

Description

Technical Field

[0001] The following disclosure relates to a liquid crystal display device.

Background Art

[0002] A liquid crystal display device generally has a structure in which a liquid crystal layer is enclosed between a pair of substrates, and is widely used for various applications by taking advantage of features such as being thin, lightweight, and having low power consumption. For example, Patent Document 1 discloses a liquid crystal display device in which a liquid crystal layer disposed between a pair of substrates contains a liquid crystal compound and a chiral dopant at a predetermined concentration. Further, Patent Document 2 discloses a liquid crystal display device having a structure in which a chiral agent that imparts rotation to liquid crystal molecules in the same direction as the direction in which the liquid crystal molecules rotate when an electric field is generated between a strip-shaped electrode and a second electrode is added to a liquid crystal layer sandwiched between a pair of substrates.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] An object of the present disclosure is to provide a liquid crystal display device with high display quality.

Means for Solving the Problems

[0005] (1) One embodiment of the present disclosure is a liquid crystal display device having a plurality of pixels arranged in a matrix including a plurality of rows and a plurality of columns, comprising, in order from the back side toward the observation side, a first substrate, a liquid crystal layer, and a second substrate, wherein the first substrate has, in order from the back side toward the observation side, a first electrode, an insulating layer, and a second electrode having one longitudinal opening for each of the plurality of pixels extending along the row or column direction of the plurality of pixels, and further comprises a plurality of nonlinear elements arranged corresponding to each pixel, and the liquid crystal layer comprises liquid crystal molecules and a chiral dopant, wherein, in a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state without applied voltage is arranged parallel to or perpendicular to the longitudinal direction of the opening.

[0006] (2) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configuration of (1) above, the liquid crystal molecules have positive dielectric anisotropy, and in a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state without applied voltage is arranged parallel to the longitudinal direction of the opening.

[0007] (3) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configuration of (1) above, the liquid crystal molecules have negative dielectric anisotropy, and in a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state without applied voltage is arranged perpendicular to the longitudinal direction of the opening.

[0008] (4) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configuration of (1), (2), or (3) above, the thickness of the liquid crystal layer is 5% or more and less than 25% of the twist pitch of the liquid crystal molecules twist-oriented by the chiral dopant.

[0009] (5) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configuration of (1), (2), (3) or (4) above, in a plan view, the orientation direction of the liquid crystal molecules on the second substrate side in the state of no applied voltage is parallel to the orientation direction of the liquid crystal molecules on the first substrate side in the state of no applied voltage.

[0010] (6) In addition to the configurations of (1), (2), (3), (4), or (5) above, one embodiment of the present disclosure has a product (Δn × d) of the birefringence Δn of the liquid crystal molecule and the thickness d (μm) of the liquid crystal layer, which is given by the following formula (1):

[0011]

number

[0012] (7) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configuration of (1), (2), (3), (4), (5) or (6) above, the pre-tilt angle of the liquid crystal molecules on the first substrate side in the state of no applied voltage is 1° or more and 5° or less with respect to the main surface of the first substrate, and the pre-tilt angle of the liquid crystal molecules on the second substrate side in the state of no applied voltage is substantially 0° with respect to the main surface of the second substrate.

[0013] (8) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configurations of (1), (2), (3), (4), (5), (6), or (7) above, the first substrate further comprises a color filter layer and a planarization film disposed on the liquid crystal layer side of the color filter layer.

[0014] (9) One embodiment of the present disclosure is a liquid crystal display device in which, in addition to the configurations of (1), (2), (3), (4), (5), (6), (7), or (8) above, the first substrate further comprises a longitudinal light-shielding film disposed between the plurality of pixels, and in a plan view, the longitudinal direction of the light-shielding film is arranged parallel to the longitudinal direction of the opening.

[0015] (10) Some embodiments of the present disclosure, in addition to the configurations of (1), (2), (3), (4), (5), (6), (7), (8), or (9) above, further include a first polarizing plate having a first polarization axis and a second polarizing plate having a second polarization axis. The first polarizing plate is disposed on the back side of the first substrate, and the second polarizing plate is disposed on the observation surface side of the second substrate. The first polarizing plate and the second polarizing plate are arranged such that the first polarization axis and the second polarization axis are orthogonal to each other. In a plan view, the second polarization axis is arranged parallel or orthogonal to the longitudinal direction of the opening. This is a liquid crystal display device.

Effects of the Invention

[0016] According to the present disclosure, a liquid crystal display device with high display quality is provided.

Brief Description of the Drawings

[0017] [Figure 1] It is a cross-sectional schematic view of the liquid crystal display device 1 according to Embodiment 1. [Figure 2] It is an enlarged plan schematic view of the liquid crystal display device 1 according to Embodiment 1. [Figure 3] It is an enlarged schematic view within the broken-line frame in FIG. 2. [Figure 4] It is a cross-sectional view taken along line A1 - A2 in FIG. 3. [Figure 5] It is an enlarged plan schematic view of the liquid crystal display device 1 according to Embodiment 2. [Figure 6] It is an enlarged plan schematic view of the liquid crystal display device 1 according to Embodiment 3. [Figure 7] It is an enlarged plan schematic view of the liquid crystal display device 1 according to Embodiment 4. [Figure 8] It is an enlarged plan schematic view of the liquid crystal display device 1R in the FFS mode of the comparative form.

Modes for Carrying Out the Invention

[0018] (Definition of Terms) In this specification, the observation side means the side closer to the screen (display surface) of the liquid crystal panel or display device, and the back side means the side further away from the screen (display surface) of the liquid crystal panel or display device.

[0019] Two lines (including axes, directions, and bearings) are said to be parallel if the angle between them (absolute value) is 0° or greater and less than 1°, preferably 0° (perfectly parallel). Two lines (including axes, directions, and bearings) are said to be orthogonal if the angle between them is greater than 89° and 90° or less, preferably 90° (perfectly orthogonal).

[0020] The voltage-applied state refers to a state in which a voltage equal to or greater than the threshold voltage is applied between the first electrode and the second electrode. The voltage-free state refers to a state in which a voltage below the threshold voltage is applied between the first electrode and the second electrode (including no voltage applied). The voltage-free state is also referred to as the voltage-free state, and the voltage-applied state is also referred to as the voltage-applied state.

[0021] The pre-tilt angle of a liquid crystal molecule represents the angle of inclination of the liquid crystal molecule relative to the direction parallel to the main surface of the substrate. The angle parallel to the main surface of the substrate is 0°, and the angle normal to the main surface of the substrate is 90°.

[0022] The following describes liquid crystal display devices according to embodiments of this disclosure. This disclosure is not limited to the embodiments described below, and design modifications can be made as appropriate within the scope of satisfying the configuration of this disclosure. In the following description, the same reference numerals will be used in common across different drawings for the same parts or parts having similar functions, and repeated explanations will be omitted as appropriate. Each aspect of this disclosure may be combined as appropriate without departing from the gist of this disclosure.

[0023] (Embodiment 1) Figure 1 is a schematic plan view of the liquid crystal display device according to this embodiment. Figure 2 is an enlarged schematic plan view of the liquid crystal display device according to this embodiment. Figure 3 is an enlarged schematic view of the area within the dashed frame (dashed rectangular frame) in Figure 2. Figure 4 is a cross-sectional view (schematic cross-sectional view) of the line A1-A2 in Figure 3.

[0024] As shown in Figures 1 to 4, the liquid crystal display device 1 of this embodiment has a plurality of pixels 10P arranged in a matrix including a plurality of rows and a plurality of columns, and comprises a first substrate 100, a liquid crystal layer 300, and a second substrate 200, in order from the back side toward the observation surface side. The first substrate 100 has, in order from the back side toward the observation surface side, a first electrode 100E1, an insulating layer 100F, and a second electrode 100E2, which has one longitudinal opening 100E2X for each pixel 10P that extends along the row or column direction of the plurality of pixels 10P. The first substrate 100 further has a plurality of nonlinear elements 100T arranged corresponding to each pixel 10P. The liquid crystal layer 300 includes liquid crystal molecules 300L and a chiral dopant. In a plan view, the orientation direction of the liquid crystal molecules 300L on the first substrate 100 side in the state without applied voltage is arranged parallel to or perpendicular to the longitudinal direction of the opening 100EX2.

[0025] In this embodiment, the liquid crystal display device 1 can generate a transverse electric field (fringe electric field) in the liquid crystal layer 300 by applying a voltage between the first electrode 100E1 and the second electrode 100E2 to perform display, thereby sufficiently suppressing light leakage and oblique color mixing and achieving good image quality. Oblique color mixing is also called color shift within the viewing angle. For example, when the liquid crystal display device 1 of this embodiment is used in a head-mounted display (HMD), a practical range of image quality can be obtained. The liquid crystal display device 1 is an FFS (Fringe Field Switching) mode liquid crystal display device.

[0026] Figure 8 is an enlarged schematic plan view of the liquid crystal display device 1R in FFS mode for comparison.

[0027] As shown in Figure 8, the liquid crystal display device 1R comprises, in order from the back side toward the observation surface side, a first polarizing plate having a first polarization axis 510AR, a first substrate, a liquid crystal layer containing liquid crystal molecules 300LR, a second substrate, and a second polarizing plate having a second polarization axis 520AR. The liquid crystal display device 1R further comprises a longitudinally shaped light-shielding film 100MR, a red color filter 170RR, a green color filter 170GR, a blue color filter 170BR, and a spacer 600R.

[0028] The first substrate of the liquid crystal display device 1R comprises a gate line 120LR, a source line 150LR, and a pair of electrodes. One of the electrodes, electrode 100ER, is provided with a longitudinally shaped opening 100EXR. The opening 100EXR provided in electrode 100ER is also called a slit or pixel slit.

[0029] In the FFS mode liquid crystal display device 1R, considering the standardization of the operating direction of liquid crystal molecules and the arrangement of polarizers and optical films, the orientation direction 300LAR of the liquid crystal molecules 300LR in the no-voltage state is arranged in a plan view such that it is parallel to the horizontal or vertical direction of the screen of the liquid crystal display device 1R and forms an angle of approximately 5° to 15° with respect to the longitudinal direction 100EAR of the pixel slit. That is, the longitudinal direction 100EAR of the pixel slit is arranged to form an angle of approximately 5° to 15° with respect to the orientation direction 300LAR of the liquid crystal molecules 300LR in the no-voltage state (in the example of Figure 8, the vertical direction of the screen of the liquid crystal display device 1R). In recent years, it has been proposed to improve transmittance by tilting the source line extension direction and the light-shielding film direction with respect to the orientation direction of the liquid crystal molecules in the no-voltage state, in line with the longitudinal direction of the pixel slit.

[0030] However, depending on the angle between the orientation direction of the liquid crystal molecules and the longitudinal direction of the pixel slit, there is a problem that light leakage and oblique color mixing are likely to occur. Furthermore, if the orientation direction of the liquid crystal molecules and the longitudinal direction of the pixel slit are parallel, the direction of movement of the liquid crystal molecules is unstable, and sufficient transmittance cannot be ensured. Further investigation by the inventors revealed that when the longitudinal direction of the pixel slit, the extension direction of the source line, and the longitudinal direction of the light-shielding film are arranged parallel to each other and tilted with respect to the orientation direction of the liquid crystal molecules, the disruption of the orientation direction of the liquid crystal molecules due to the step difference between the source line and the light-shielding film, and the optical diffraction phenomenon caused by the thin film (e.g., light-shielding film, source line, etc.) that forms a certain angle with the polarization direction of the polarization axis can cause light leakage. In addition, it was found that when the orientation direction of the liquid crystal molecules and the longitudinal direction of the pixel slit are arranged to form the above angle, it is difficult to take the measure of making the light-shielding film wider in order to sufficiently suppress oblique color mixing, considering the transmittance.

[0031] In contrast, the liquid crystal display device 1 of this embodiment solves the above problem by having the longitudinal direction 100E2A of the opening 100E2X arranged parallel to the horizontal or vertical direction (row or column direction of the multiple pixels 10P) of the screen 10 of the liquid crystal display device 1, similar to the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side when no voltage is applied, and by including a chiral dopant together with the liquid crystal molecules 300L in the liquid crystal layer 300. In FFS mode, the electric field in the region where the electrodes are close to the substrate on which the pixel electrodes or common electrodes are formed tends to affect the operation of the liquid crystal molecules. Therefore, the operation direction of the liquid crystal molecules 301L is determined by the effect of the chiral dopant on the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side. As a result, even if the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 is arranged parallel or perpendicular to the longitudinal direction 100E2A of the aperture 100E2X, the operating direction of the liquid crystal molecules 300L is controlled to a constant direction. Therefore, the liquid crystal display device 1 has a high display quality. Furthermore, in such a liquid crystal display device 1, for example, the source line 150L and the light-shielding film 100M can be arranged parallel to the horizontal or vertical direction of the screen 10 of the liquid crystal display device 1 (the polarization direction can also be arranged parallel to the horizontal or vertical direction of the screen 10 of the liquid crystal display device 1), and the liquid crystal display device 1 can more effectively prevent light leakage and oblique color mixing while ensuring high transmittance.

[0032] The liquid crystal display device 1 of this embodiment will be described in more detail below.

[0033] As shown in Figures 1 to 4, the liquid crystal display device 1 of this embodiment comprises, in order from the back side toward the observation surface side, a first substrate 100, a liquid crystal layer 300, and a second substrate 200. The liquid crystal display device 1 includes an active area (image display area) on which an image is displayed, and the active area is composed of a plurality of pixels 10P arranged in a matrix in the horizontal direction 11D and the vertical direction 12D of the screen 10.

[0034] <First board> The first substrate 100 comprises a first support substrate 110, a plurality of gate lines 120L arranged on the liquid crystal layer 300 side of the first support substrate 110, a first insulating layer 130 arranged on the liquid crystal layer 300 side of the plurality of gate lines 120L, and a plurality of source lines 150L arranged on the liquid crystal layer 300 side of the first insulating layer 130. The plurality of gate lines 120L are arranged parallel to the horizontal direction 11D of the screen 10. The plurality of source lines 150L are arranged parallel to the vertical direction 12D of the screen 10. The plurality of gate lines 120L and the plurality of source lines 150L are formed in a grid pattern as a whole so as to demarcate each pixel 10P. Nonlinear elements 100T are arranged at the intersections of each gate line 120L and each source line 150L.

[0035] The horizontal direction 11D forms a 90° angle with respect to the vertical direction 12D. The horizontal direction 11D corresponds to the row direction (hereinafter also simply referred to as the "row direction") of the matrix-arranged picture elements 10P, and the vertical direction 12D corresponds to the column direction (hereinafter also simply referred to as the "column direction") of the matrix-arranged picture elements 10P.

[0036] Preferably, the gate line 120L is arranged perpendicular to the longitudinal direction 100E2A of the opening 100E2X in a plan view. That is, the first substrate 100 is provided with a gate line 120L, and preferably the gate line 120L is arranged perpendicular to the longitudinal direction 100E2A of the opening 100E2X in a plan view. In this case, one of the extending direction of the gate line 120L and the longitudinal direction 100E2A of the opening 100E2X may be arranged parallel to the horizontal direction 11D of the screen 10, and the other may be arranged parallel to the vertical direction 12D of the screen 10. Therefore, the liquid crystal display device 1 can achieve higher resolution while further improving transmittance and reducing oblique color mixing.

[0037] In this embodiment, the gate line 120L is arranged parallel to the horizontal direction 11D of the screen 10, and the source line 150L is arranged parallel to the vertical direction 12D of the screen 10. However, the gate line 120L may be arranged parallel to the vertical direction 12D of the screen 10, and the source line 150L may be arranged parallel to the horizontal direction 11D of the screen 10.

[0038] Each nonlinear element 100T is a three-terminal switch (e.g., a thin-film transistor (TFT)) having a semiconductor layer 100S, a gate electrode protruding from (or being part of) the corresponding gate line 120L, a source electrode protruding from (or being part of) the corresponding source line 150L, ​​a drain electrode 150D connected to the corresponding pixel electrode among a plurality of pixel electrodes (first electrode 100E1 in this embodiment), and a semiconductor layer 100S. The source electrode and drain electrode 150D are electrodes provided in the same source wiring layer 150 as the source line 150L, ​​and the gate electrode is an electrode provided in the same gate wiring layer 120 as the gate line 120L. The semiconductor layer 100S is connected to the drain electrode 150D via a through-hole 10CH1. The first electrode 100E1 is connected to the drain electrode 150D via a through-hole 10CH2.

[0039] A gate driver is connected to gate line 120L, and a source driver is connected to source line 150L. Controllers are connected to both the gate driver and the source driver. The gate driver sequentially supplies scan signals to gate line 120L based on control from the controller. The source driver supplies data signals to source line 150L based on control from the controller at the timing when the nonlinear element 100T enters a voltage-applied state due to the scan signal.

[0040] Each pixel electrode is set to a potential corresponding to the data signal supplied via the corresponding nonlinear element 100T, generating a fringe electric field between the common electrode and the pixel electrode, causing the liquid crystal molecules 300L of the liquid crystal layer 300 to rotate. In this way, the magnitude of the voltage applied between the common electrode and the pixel electrode is controlled, changing the retardation of the liquid crystal layer 300 and controlling the transmission or opacity of light.

[0041] The various wirings and electrodes constituting the gate wire 120L, source wire 150L, ​​and nonlinear element 100T can be formed by depositing metals such as copper, titanium, aluminum, molybdenum, and tungsten, or their alloys, in single or multiple layers using sputtering or the like, followed by patterning using photolithography or the like. For these various wirings and electrodes formed in the same layer, the manufacturing process can be made more efficient by using the same material for each component.

[0042] The first substrate 100 comprises, in order toward the liquid crystal layer 300 side, a first support substrate 110, a gate wiring layer 120 on which gate lines 120L are provided, a first insulating layer 130, a semiconductor layer, a source wiring layer 150 on which source lines 150L are provided, a second insulating layer 160, a color filter layer 170, a planarization film 180, a first electrode 100E1, an insulating layer 100F, a second electrode 100E2 on which an opening 100E2X is provided, and a light-shielding film 100M.

[0043] The first insulating layer 130 is a gate insulating layer. The first insulating layer 130 is, for example, an inorganic insulating film. As an inorganic insulating film, for example, silicon nitride (SiN x ), inorganic films such as silicon dioxide (SiO2) (with relative permittivity ε=5~7), or laminated films thereof can be used.

[0044] The semiconductor layer preferably contains an oxide semiconductor or p-Si (Polycrystalline Silicon). Examples of oxide semiconductors include, but are not limited to, IGZO (In-Ga-Zn-O: indium gallium zinc oxide) and ZnO (zinc oxide).

[0045] The second insulating layer 160 is, for example, an inorganic insulating film. Examples of inorganic insulating films include silicon nitride (SiN). x ), inorganic films such as silicon dioxide (SiO2) (with relative permittivity ε=5~7), or laminated films thereof can be used.

[0046] The color filter layer 170 is positioned on the liquid crystal layer 300 side of the second insulating layer 160. The color filter layer 170 is composed of, for example, a red color filter 170R, a blue color filter 170B, and a green color filter 170G.

[0047] Multiple pixels 10P include, for example, a red pixel 10PR equipped with a red color filter 170R, a blue pixel 10PB equipped with a blue color filter 170B, and a green pixel 10PG equipped with a green color filter 170G. Three pixels 10P, namely red pixel 10PR, blue pixel 10PB, and green pixel 10PG, constitute one pixel 1P. Within one pixel 1P, the three pixels 10P are arranged in a striped pattern.

[0048] In this embodiment, the first substrate 100 has a color filter layer 170, but the second substrate 200 may have the color filter layer 170 instead of the first substrate 100. The color filter layer 170 is, for example, a microcolor filter layer.

[0049] The planarization film 180 is positioned on the liquid crystal layer 300 side of the color filter layer 170. The planarization film 180 is an insulating film that absorbs irregularities on the surface (substrate) on which the film is formed, and flattens the substrate surface on which the film is formed. The planarization film 180 makes it possible to maintain a constant cell thickness in the liquid crystal display device 1. An organic insulating film is preferred as the planarization film 180. As the organic insulating film, for example, an organic film such as acrylic resin, polyimide resin, or novolac resin can be used. As the organic insulating film, for example, an organic film with a low relative permittivity (relative permittivity ε = 2 to 5), such as a photosensitive acrylic resin, can be preferably used.

[0050] The first electrode 100E1 faces the second electrode 100E2 at least partially via an insulating layer 100F. The second electrode 100E2 is provided with an opening 100E2X that extends along the row or column direction of the plurality of pixels 10P. This enables the liquid crystal display device 1 to realize an FFS mode display mode. Here, "partially facing" the first electrode 100E1 and the second electrode 100E2 means that at least a part of the first electrode 100E1 faces at least a part of the second electrode 100E2. The second electrode 100E2 is provided with one (only one) longitudinal opening 100E2X for each pixel 10P.

[0051] One of the first electrode 100E1 and the second electrode 100E2 is a pixel electrode, and the other electrode is a common electrode. In this embodiment, the first electrode 100E1 is a pixel electrode, and the second electrode 100E2 is a common electrode.

[0052] Pixel electrodes are electrodes positioned in each region enclosed by two adjacent gate lines 120L and two adjacent source lines 150L. Pixel electrodes are positioned for each pixel 10P. Each pixel electrode is connected to a corresponding nonlinear element 100T, and is connected to the corresponding source line 150L via a semiconductor layer provided by the nonlinear element 100T. The pixel electrodes are set to a potential corresponding to the data signal supplied via the corresponding nonlinear element 100T.

[0053] A common electrode is, for example, an electrode formed on almost the entire surface, regardless of the boundary of pixel 10P. A common signal, maintained at a constant value, is supplied to the common electrode, and the common electrode is maintained at a constant potential.

[0054] The second electrode 100E2 is positioned closer to the liquid crystal layer 300 than the first electrode 100E1. The opening 100E2X of the (upper layer) second electrode 100E2, which is positioned closer to the liquid crystal layer 300, is located on the lower layer first electrode 100E1. In this embodiment, the lower layer first electrode 100E1 is located in at least the region corresponding to the opening 100E2X, but there may be regions within the region corresponding to the opening 100E2X where the first electrode 100E1 does not exist. For example, if the lower layer first electrode 100E1 is a common electrode, the first electrode 100E1 may be a solid electrode with an opening in the region corresponding to the through-hole connecting the upper layer second electrode 100E2, which is a pixel electrode, and the drain electrode of the nonlinear element 100T.

[0055] The electric field applied to the liquid crystal molecules 300L is determined by the potential difference between the opening 100E2X of the upper second electrode 100E2 and the lower first electrode 100E1. Therefore, in terms of the operation of the liquid crystal molecules, either the upper electrode (second electrode 100E2) or the lower electrode (first electrode 100E1) may be a pixel electrode or a common electrode. When the upper electrode is a pixel electrode, it must be electrically insulated from adjacent pixel electrodes. For example, the upper electrode has a configuration in which one opening 100E2X is provided in each square-shaped pixel electrode. On the other hand, when the upper electrode is a common electrode, the upper electrode has a configuration in which one opening 100E2X is provided in the region corresponding to each pixel of a solid electrode that extends across the entire screen area (i.e., the total number of openings in the common electrode is the same as the number of pixels).

[0056] It is preferable that the first electrode 100E1 is a pixel electrode and the second electrode 100E2 is a common electrode. Such a liquid crystal display device 1 makes it possible to reduce the step difference caused by the electrodes and to easily form through-holes 10CH2 between the pixel electrodes and the drain electrodes. Specifically, positional interference between the through-holes 10CH2 and the light-shielding film 100M becomes less likely, simplifying the design of the liquid crystal display device 1. Furthermore, if the light-shielding film 100M is a conductor such as a metal, electrical interference between the through-holes 10CH2 and the light-shielding film 100M becomes less likely, simplifying the design of the liquid crystal display device 1.

[0057] The first electrode 100E1 may be a common electrode, and the second electrode 100E2 may be a pixel electrode. Such a liquid crystal display device 1 can reduce the parasitic capacitance [Cgd] of the nonlinear element 100T.

[0058] The first electrode 100E1 and the second electrode 100E2 can be formed by depositing a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or tin oxide (SnO), or an alloy thereof, in a single or multiple layer by sputtering or the like, and then patterning it using photolithography.

[0059] The insulating layer 100F is an interlayer insulating film and has the function of insulating the first electrode 100E1 and the second electrode 100E2. An inorganic insulating film can be used as the insulating layer 100F. For example, silicon nitride (SiN) x ), inorganic films such as silicon dioxide (SiO2) (with relative permittivity ε=5~7), or laminated films thereof can be used.

[0060] The first substrate 100 is preferably provided with a light-shielding film 100M. The light-shielding film 100M has the function of blocking light. The light absorption rate of the light-shielding film 100M should be 30% or more. The sum of the light absorption rate and reflectance of the light-shielding film 100M is preferably 80% or more, and more preferably 95% or more. The light absorption rate of the light-shielding film 100M is determined by performing general reflectance measurements and general transmittance measurements and subtracting the reflectance and transmittance from 100%.

[0061] The light-shielding film 100M preferably contains a metal. The metal contained in the light-shielding film 100M is preferably a metal with relatively low reflectivity, such as molybdenum or titanium. The light-shielding film 100M may also contain materials other than metal.

[0062] The 100M light-shielding film is, for example, a metal film. The reflectance of the above metal film is, for example, 40% or more and 60% or less. The reflectance is the reflectance in the visible light region (e.g., wavelength 380nm to 780nm) and is measured by a method compliant with JIS R3106:2019. As a measuring device, for example, a spectrophotometer (e.g., Konica Minolta CM-700d) is used.

[0063] The light-shielding film 100M may be a laminate containing a metal film and an insulating film. The insulating film included in the laminate is, for example, an inorganic insulating film. The laminate may be, for example, a laminate in which an insulating film such as silicon oxide or silicon nitride is sandwiched between a plurality of metal films. When the light-shielding film 100M is the above laminate, the metal film included in the laminate is preferably a semi-transparent thin metal film layer. By adopting this configuration, the reflectivity of the light-shielding film 100M can be reduced by utilizing light interference.

[0064] The light-shielding film 100M is preferably arranged between a plurality of pixels 10P (boundaries of pixels 10P), and the shape of the light-shielding film 100M is preferably longitudinal. That is, the first substrate 100 is provided with longitudinally shaped light-shielding films 100M arranged between a plurality of pixels 10P (boundaries of pixels 10P), and in a plan view, the longitudinal direction of the light-shielding film 100M is preferably arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X. In such a configuration, the liquid crystal display device 1 can be arranged parallel to the horizontal direction 11D or vertical direction 12D of the screen 10 of the liquid crystal display device 1, thereby achieving high resolution while further improving transmittance and reducing oblique color mixing.

[0065] It is preferable that the longitudinally shaped light-shielding film 100M is arranged in an island-like manner between multiple pixels 10P (boundaries of pixels 10P) such that at least a portion of it overlaps the source line 150L. This allows the liquid crystal display device 1 to more effectively suppress color shifts during monochrome display caused by light leakage from adjacent pixels 10P, mainly at oblique viewing angles.

[0066] <Second board> The second substrate 200 includes a second support substrate 210.

[0067] The second substrate 200 may also have a second substrate-side light-shielding film 20BM on the liquid crystal layer 300 side of the second support substrate 210. The second substrate-side light-shielding film 20BM may be provided in a grid pattern, for example, to partition each color filter.

[0068] The second substrate-side light-shielding film 20BM is, for example, a black matrix layer. The material of the black matrix layer is not particularly limited as long as it has light-shielding properties, but a resin material containing a black pigment or a metal material with light-shielding properties is preferably used. The black matrix layer is formed, for example, by a photolithography method in which a photosensitive resin containing a black pigment is applied to form a film, followed by exposure and development.

[0069] Preferably, the light-shielding film 20BM on the second substrate side extends along the row direction (horizontal direction 11D in this embodiment) between two adjacent pixels 10P in the column direction (vertical direction 12D in this embodiment), and is not positioned between two adjacent pixels 10P in the row direction (it is not extended along the column direction between two adjacent pixels 10P in the row direction). In this embodiment of the liquid crystal display device 1, peeling of the light-shielding film 20BM on the second substrate side can be suppressed compared to the case where the light-shielding film 20BM on the second substrate side extends both between two adjacent pixels 10P in the column direction and between two adjacent pixels 10P in the row direction. In addition, from the viewpoint of alignment accuracy when bonding the first substrate 100 and the second substrate 200, the aperture ratio can be increased compared to the case where the light-shielding film 20BM on the second substrate side extends in the column direction. The second substrate-side light-shielding film 20BM extends, for example, in the row direction between the outer frame of the screen 10 of the liquid crystal display device 1 and each pixel 10P. In this specification, "extending along a certain direction" means "extending parallel to a certain direction."

[0070] <Spacer> A spacer 600 may be provided between the first substrate 100 and the second substrate 200. The spacer 600 has the function of securing a gap in the space where the liquid crystal layer 300 is formed. The spacer 600 is placed on at least one of the first substrate 100 and the second substrate 200, and may be placed on both substrates. For example, a spacer provided on the second substrate 200 does not need to have its tip in contact with the first substrate 100.

[0071] The spacer 600 has, for example, a columnar shape. The planar shape of the spacer 600 may be, for example, a polygon, a circle, or an ellipse. The spacer 600 may be, for example, a frustocone, a cylinder, an elliptical frustocone, an elliptical column, a pyramidal frustocone, or a prismatic prism. Examples of pyramidal frustocones include pyramidal frustocones. Examples of prismatic prisms include prismatic prisms.

[0072] The spacer 600 preferably contains, for example, a cured product of a photosensitive resin. Examples of photosensitive resins include resins having ultraviolet-reactive functional groups.

[0073] <Liquid crystal layer> The liquid crystal layer 300 contains liquid crystal molecules 300L and a chiral dopant. More specifically, the liquid crystal layer 300 is composed of a liquid crystal material containing liquid crystal molecules 300L and a chiral dopant, and the amount of light transmitted is controlled by applying a voltage to the liquid crystal layer 300 and changing the orientation state of the liquid crystal molecules 300L in the liquid crystal material according to the applied voltage. The liquid crystal material exhibits nematic liquid crystal properties within a certain temperature range.

[0074] In this embodiment, the liquid crystal molecules 300L have positive dielectric anisotropy. A liquid crystal display device 1 in this configuration can further improve the response speed. The dielectric anisotropy (Δε) is given by the following equation (L1): Δε = (dielectric constant in the long axis direction of the liquid crystal molecule) - (dielectric constant in the short axis direction of the liquid crystal molecule) Equation (L1) Defined by: Liquid crystal molecules having a positive value of dielectric anisotropy are also referred to as positive-type liquid crystals, and liquid crystal molecules having a negative value of dielectric anisotropy are also referred to as negative-type liquid crystals. The long axis direction of the liquid crystal molecules 300L becomes the alignment direction (slow axis direction). The liquid crystal molecules 300L are homogeneously aligned in the state without applied voltage.

[0075] A chiral dopant is also referred to as a chiral dopant. The chiral dopant is not particularly limited. For example, when the liquid crystal layer 300 is viewed in plan view from the observation surface side, those that cause a clockwise twist in the liquid crystal molecules toward the front direction are preferably used. Specifically, for example, S-811 (manufactured by Merck Electronics) etc. may be used. The chiral dopant contained in the liquid crystal layer 300 may be only one type, or may be two or more types.

[0076] In the liquid crystal layer 300, the liquid crystal molecules 300L are twisted and aligned. The content of the chiral dopant contained in the liquid crystal layer 300 (the total amount when two or more types are included) is preferably adjusted so as to satisfy the relational expression of "(0.05 × p) < d < (0.25 × p)", where d is the thickness of the liquid crystal layer and p is the twist pitch of the liquid crystal molecules 300L twisted and aligned by the chiral dopant. In other words, it is preferable that the thickness (d) of the liquid crystal layer is 5% or more and less than 25% of the twist pitch (p) of the liquid crystal molecules 300L twisted and aligned by the chiral dopant. Thereby, the liquid crystal display device 1 is more sufficiently suppressed from generating display defects, and also has a faster response speed when a voltage is applied. Generally, even when the content of the chiral dopant contained in the liquid crystal layer 300 is the same, as the ambient temperature decreases, the above-mentioned twist pitch (p) tends to become shorter. Therefore, it is preferable to satisfy the above relationship at the lowest temperature in the operating temperature range of the liquid crystal display device.

[0077] The thickness of the liquid crystal layer (also referred to as cell thickness) (d) is more preferably 10% or more of the above twist pitch (p), and more preferably 15% or more. The twist pitch is the thickness of the liquid crystal layer 300 corresponding to one turn of the spiral structure (360° twist).

[0078] In the liquid crystal display device 1 of this embodiment, in which the liquid crystal molecules 300L have positive dielectric anisotropy, in a plan view, the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side in the state without applied voltage is arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X, and the liquid crystal layer 300 contains a chiral dopant in the manner described above. As described above, a liquid crystal display device 1 of this embodiment has high display quality and a sufficiently fast response speed, and can also suppress light leakage and oblique color mixing more sufficiently while ensuring high transmittance.

[0079] In a plan view, it is preferable that the orientation direction 302LA of the liquid crystal molecules 302L on the second substrate 200 side in the no-voltage state is parallel to the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side in the no-voltage state. That is, it is preferable that the orientation direction 302LA of the liquid crystal molecules 302L is arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X. This allows the liquid crystal display device 1 to achieve higher contrast and also improve response speed.

[0080] The orientation direction of liquid crystal molecules, unless otherwise specified, refers to the orientation direction of liquid crystal molecules located in the center of the aperture of the second electrode in a plan view. The center of the aperture is the region where the center of the aperture in the longitudinal direction (a region with a certain range) and the center of the aperture in the width direction (a direction that forms a 90° angle with the longitudinal direction) (a region with a certain range) overlap. The center of the aperture in the longitudinal direction is, for example, the region located in the middle of the three regions obtained by dividing the aperture into three equal parts in the longitudinal direction. The center of the aperture in the width direction is, for example, the region located in the middle of the three regions obtained by dividing the aperture into three equal parts in the width direction.

[0081] The orientation direction of liquid crystal molecules in the absence of applied voltage can be determined as follows. Since the alignment film (for example, an alignment film using a commonly used heat-resistant polymer) has a phase difference in the orientation direction of the liquid crystal molecules, the direction of the phase difference of the alignment film measured by a micro-polarization measuring device can be used as the orientation direction of the liquid crystal molecules in the state without applied voltage. That is, the direction of the phase difference of the first alignment film 410 can be used as the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side in the state without applied voltage. Similarly, the direction of the phase difference of the second alignment film 420 can be used as the orientation direction 302LA of the liquid crystal molecules 302L on the second substrate 200 side in the state without applied voltage. As a micro-polarization measuring device, for example, the "TFM-120AFT-PC" manufactured by Oak Manufacturing Co., Ltd. is used.

[0082] If the phase difference of the alignment film is minute and it is difficult to determine the direction of the phase difference of the alignment film, a laminate comprising an alignment film, a liquid crystal layer containing liquid crystal molecules, and a polarizing plate in this order may be subjected to polarized light having a polarization axis that forms a 90° angle with respect to the transmission axis of the polarizing plate from the direction of the alignment film, and the direction showing the minimum transmittance may be defined as the orientation direction of the liquid crystal molecules in the voltage-free state.

[0083] In this embodiment, it is preferable that the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side in the no-voltage state is substantially 0° with respect to the main surface of the first substrate 100, and the pre-tilt angle of the liquid crystal molecules 302L on the second substrate 200 side in the no-voltage state is substantially 0° with respect to the main surface of the second substrate 200. This allows the liquid crystal display device 1 to achieve even higher contrast and higher transmittance. In this specification, substantially 0° with respect to the main surface of the substrate means 0° or more and less than 1° with respect to the main surface of the substrate, preferably 0° or more and 0.5° or less, and more preferably 0° or more and 0.2° or less.

[0084] <Orientation film> The liquid crystal display device 1 preferably further comprises alignment films. More specifically, the liquid crystal display device 1 preferably comprises a first alignment film 410 between the first substrate 100 and the liquid crystal layer 300, and a second alignment film 420 between the second substrate 200 and the liquid crystal layer 300 (see Figures 1 to 4). The first alignment film 410 and the second alignment film 420 have the function of controlling the orientation of the liquid crystal molecules 300L contained in the liquid crystal layer 300.

[0085] The first alignment film 410 and the second alignment film 420 are preferably horizontal alignment films. This makes it easier to control the pre-tilt angle of the liquid crystal molecules 300L within the above range. The horizontal alignment film has the function of aligning the liquid crystal molecules horizontally when no voltage is applied.

[0086] Methods for aligning the first alignment film 410 and the second alignment film 420 include methods such as severing polymer chains in a certain direction of the alignment film by irradiation with polarized ultraviolet light (decomposition-type photoalignment method), generating a cis-trans isomerization reaction in the photofunctional groups in the alignment film by irradiation with polarized ultraviolet light (isomerization-type photoalignment method), and rubbing the surface of the alignment film with a napped cloth to increase the proportion of polymer chains on the surface aligned in a certain direction (rubbing alignment method). The orientation treatment methods for the first alignment film 410 and the second alignment film 420 may be the same or different.

[0087] <Polarizing plate> The liquid crystal display device 1 preferably further comprises polarizing plates. More specifically, the liquid crystal display device 1 preferably further comprises a first polarizing plate 510 having a first polarization axis 510A and a second polarizing plate 520 having a second polarization axis 520A (see Figures 1 to 4). The first polarizing plate 510 is arranged on the back side of the first substrate 100, and the second polarizing plate 520 is arranged on the observation surface side of the second substrate 200.

[0088] It is preferable that the first polarizing plate 510 and the second polarizing plate 520 are arranged so that the first polarization axis 510A and the second polarization axis 520A are orthogonal to each other. Here, the polarization axis means the transmission axis. The first polarizing plate 510 and the second polarizing plate 520 are, for example, absorption type polarizing plates, and the first polarizing plate 510 has a first polarization axis 510A and a first absorption axis orthogonal to the first polarization axis 510A, and the second polarizing plate 520 has a second polarization axis 520A and a second absorption axis orthogonal to the second polarization axis 520A. A liquid crystal display device 1 in this configuration can further suppress light leakage and achieve even better image quality.

[0089] The second polarization axis 520A is preferably arranged in a plan view parallel to or perpendicular to the longitudinal direction 100E2A of the aperture 100E2X, i.e., the orientation direction 302LA of the liquid crystal molecules 302L on the second substrate 200 side in the state without applied voltage. A liquid crystal display device 1 in this configuration facilitates the design of the optical system on the light-emitting side, suppresses light leakage, and can improve the contrast of the liquid crystal display device 1.

[0090] For example, in a plan view, the first polarization axis 510A may be arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X (the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side when no voltage is applied), and the second polarization axis 520A may be arranged perpendicular to the longitudinal direction 100E2A of the aperture 100E2X (the orientation direction 302LA of the liquid crystal molecules 302L on the second substrate 200 side when no voltage is applied). Alternatively, in a plan view, the first polarization axis 510A may be arranged perpendicular to the longitudinal direction 100E2A of the aperture 100E2X, and the second polarization axis 520A may be arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X.

[0091] <Other components, etc.> The liquid crystal display device 1 preferably further includes a light source. The light source is not particularly limited as long as it emits light, and may be a direct-lit type, edge-lit type, or any other type. The light source preferably includes, for example, a light-emitting diode (LED), a light guide plate, and a reflective sheet, and may further include a diffusion sheet or a prism sheet. For example, the liquid crystal display device 1 shown in Figure 4 includes a backlight (not shown) on the back side of the first polarizing plate 510.

[0092] The liquid crystal display device 1 is also composed of multiple components, including the aforementioned components, as well as external circuits such as TCP (tape carrier package) and PCB (printed circuit board); optical films such as viewing angle expansion film and brightness enhancement film; and a bezel (frame). Some components may be incorporated into other components. These are not particularly limited, and those commonly used in the field of liquid crystal displays can be used, so a detailed explanation is omitted.

[0093] (Embodiment 2) In this embodiment, we will mainly describe the features specific to this embodiment, and will omit explanations of content that overlaps with Embodiment 1 described above. Figure 5 is an enlarged schematic plan view of the liquid crystal display device 1 according to this embodiment. The liquid crystal display device 1 of this embodiment is substantially the same as the liquid crystal display device 1 of Embodiment 1, except that the dielectric anisotropy of the liquid crystal molecules 300L and the orientation direction of the liquid crystal molecules 300L in the no-voltage state are different.

[0094] In the liquid crystal display device 1 of the above embodiment 1, the liquid crystal molecules 300L have positive dielectric anisotropy, but in this embodiment, the liquid crystal molecules 300L have negative dielectric anisotropy. A liquid crystal display device 1 of this form can improve transmittance.

[0095] In the liquid crystal display device 1 of this embodiment, in which the liquid crystal molecules 300L have negative dielectric anisotropy, in a plan view, the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side in the state without applied voltage is arranged orthogonally to the longitudinal direction 100E2A of the aperture 100E2X, and the liquid crystal layer 300 contains a chiral dopant in the manner described above. As described above, a liquid crystal display device 1 of this embodiment has high display quality and sufficiently high transmittance, and it is also possible to suppress light leakage and oblique color mixing more sufficiently while ensuring high transmittance.

[0096] Furthermore, in a plan view, it is preferable that the orientation direction 302LA of the liquid crystal molecules 302L on the second substrate 200 side in the no-voltage state is parallel to the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side in the no-voltage state. That is, it is preferable that the orientation direction 302LA of the liquid crystal molecules 302L is also arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X. This allows the liquid crystal display device 1 to achieve higher contrast and also improve response speed.

[0097] (Embodiment 3) In this embodiment, we will mainly describe the features specific to this embodiment, and will omit explanations of content that overlaps with Embodiment 1 described above. Figure 6 is an enlarged schematic plan view of the liquid crystal display device 1 according to this embodiment. The liquid crystal display device 1 of this embodiment has substantially the same configuration as the liquid crystal display device 1 of Embodiment 1, except that the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side in the state of no applied voltage is 1° or more with respect to the main surface of the first substrate 100. The pre-tilt angle of the liquid crystal molecules 302L on the second substrate 200 side in the state of no applied voltage is substantially 0° with respect to the main surface of the second substrate 200.

[0098] In the state where no voltage is applied, the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side is preferably 1° or more and 5° or less. In this embodiment of the liquid crystal display device 1, the asymmetry of the liquid crystal molecules 300L on the first substrate 100 side and the second substrate 200 side is increased due to the influence of the chiral dopant, which makes it easier for the liquid crystal molecules 301L on the first substrate 100 side to move. Therefore, the orientation stability of the liquid crystal molecules 300L when a charge is applied is further improved, and the liquid crystal display device 1 can further improve its response speed. In other words, when the pre-tilt angle of the liquid crystal molecules 301L is within the above range, the liquid crystal molecules 300L can maintain a more stable orientation state, and the liquid crystal display device 1 can exhibit better display characteristics. The above pre-tilt angle is more preferably 1° or more and 4° or less, even more preferably 1° or more and 3° or less, and particularly preferably 2° or more and 3° or less.

[0099] In this embodiment as well, the first alignment film 410 and the second alignment film 420 are preferably horizontal alignment films. Here, as a method for easily adjusting the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side to within the above range, for example, a method can be used in which the first alignment film 140 is aligned by a rubbing method using a rubbing alignment film (for example, a liquid crystal alignment material (SunEver) "SE" series manufactured by Nissan Chemical Corporation). The direction of the rubbing process may be, for example, from top to bottom in Figure 6, or from bottom to top in Figure 6. If the rubbing process is performed in the former direction, a downward pre-tilt angle is generated, and if the rubbing process is performed in the latter direction, an upward pre-tilt angle is generated. Regardless of which direction the rubbing process is performed in, the effect obtained is substantially the same.

[0100] (Embodiment 4) In this embodiment, we will mainly describe the features specific to this embodiment, and will omit explanations of content that overlaps with Embodiment 2 described above. Figure 7 is an enlarged schematic plan view of the liquid crystal display device 1 according to this embodiment. The liquid crystal display device 1 of this embodiment has substantially the same configuration as the liquid crystal display device 1 of Embodiment 2, except that the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side in the state of no applied voltage is 1° or more with respect to the main surface of the first substrate 100. The pre-tilt angle of the liquid crystal molecules 302L on the second substrate 200 side in the state of no applied voltage is substantially 0° with respect to the main surface of the second substrate 200.

[0101] In the state where no voltage is applied, the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side is preferably 1° or more and 5° or less. In this embodiment of the liquid crystal display device 1, the asymmetry of the liquid crystal molecules 300L on the first substrate 100 side and the second substrate 200 side is increased due to the influence of the chiral dopant, which makes it easier for the liquid crystal molecules 301L on the first substrate 100 side to move. Therefore, the orientation stability of the liquid crystal molecules 300L when a charge is applied is further improved, and the liquid crystal display device 1 can further improve its response speed. In other words, when the pre-tilt angle of the liquid crystal molecules 301L is within the above range, the liquid crystal molecules 300L can maintain a more stable orientation state, and the liquid crystal display device 1 can exhibit better display characteristics. The above pre-tilt angle is more preferably 1° or more and 4° or less, even more preferably 1° or more and 3° or less, and particularly preferably 2° or more and 3° or less.

[0102] In this embodiment as well, the first alignment film 410 and the second alignment film 420 are preferably horizontal alignment films. For a method to easily adjust the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side to within the above range, refer to the description in Embodiment 3 above.

[0103] The embodiments of this disclosure have been described above, but all of the individual matters described may apply to the disclosure as a whole.

[0104] The present disclosure will be described in more detail below with reference to examples, but the present disclosure is not limited to these examples. Contrast was measured using a "Colorimeter BM-5A" (manufactured by Topcon Techno House Co., Ltd.), and transmittance and response speed were measured using an "LCD-5200" (manufactured by Otsuka Electronics Co., Ltd.).

[0105] (Example 1-1) A liquid crystal display device 1 of Example 1-1, corresponding to the liquid crystal display device 1 of Embodiment 1, was fabricated (see Figures 1 to 4). The liquid crystal display device 1 in this example was an active matrix liquid crystal display device for HMD with a resolution of 1400 ppi. The size of each pixel (each pixel 1P) was 18 μm square, and the size of each subpixel (each picture element 10P) was 6 μm × 18 μm.

[0106] The liquid crystal display device 1 comprises, in order from the back side toward the observation surface side, a first polarizing plate 510, a first substrate 100, a first alignment film 410, a liquid crystal layer 300, a second alignment film 420, a second substrate 200, and a second polarizing plate 520.

[0107] The first substrate 100 of the liquid crystal display device 1 was fabricated as follows. First, a gate wiring layer 120 including a gate electrode and gate line 120L, a gate insulating layer (first insulating layer 130), a TFT (nonlinear element 100T) having IGZO® as a semiconductor layer, and a source wiring layer 150 including a source electrode and source line 150L were formed in order on the first support substrate 110. The gate line 120L extended parallel to the horizontal direction 11D of the screen 10, and the source line 150L extended parallel to the vertical direction 12D of the screen 10. The source line 150L also functions as a light-shielding film between pixels 10P. Although IGZO® was used for the semiconductor layer driving the pixels 10P, a TFT having p-Si as a semiconductor layer was used in the peripheral circuit section of the liquid crystal display device 1.

[0108] Furthermore, a color filter layer 170, consisting of a red color filter 170R, a blue color filter 170B, and a green color filter 170G, was formed on the source wiring layer 150 using a colored organic resist. Next, a planarization film 180, made of an organic insulating film, was formed on the color filter layer 170 to ensure flatness. Then, through-holes 10CH2 for electrically connecting the drain electrode and the pixel electrode of the TFT were formed, penetrating the color filter layer 170 and the planarization film 180.

[0109] Next, in order to perform display in FFS mode, a first electrode 100E1, which is a pixel electrode, an insulating layer 100F, and a second electrode 100E2, which is a common electrode, were formed on the planarized film 180 in that order. The first electrode 100E1 and the second electrode 100E2 were transparent electrodes. Then, a long-shaped light-shielding film 100M made of molybdenum was formed on the second electrode 100E2 to fabricate the first substrate 100.

[0110] Furthermore, a first alignment film 410 and a spacer 600 for ensuring cell thickness were formed on the light-shielding film 100M in that order. In this embodiment, the spacer 600 was formed on the first substrate 100, but the spacer 600 may be formed on the second substrate 200, or on both the first substrate 100 and the second substrate 200.

[0111] The second electrode 100E2 is provided with longitudinally shaped openings 100E2X that extend along the row or column directions of the multiple pixels 10P. In a plan view, the longitudinal direction 100E2A of the openings 100E2X is positioned parallel to the vertical direction 12D of the screen 10 (specifically, at an angle of 0°). Also in a plan view, the longitudinal direction of the light-shielding film 100M is positioned parallel to the vertical direction 12D of the screen 10 (specifically, at an angle of 0°).

[0112] The first alignment film 410 was a photodegradable alignment film in which liquid crystal molecules are aligned perpendicular to the transmitted polarized light upon irradiation with polarized ultraviolet light. In a plan view, the first alignment film 410 was irradiated with polarized ultraviolet light to perform a photoalignment treatment so that the alignment direction 301LA of the liquid crystal molecules 301L on the first substrate 100 side, in the state without applied voltage, is arranged parallel to the longitudinal direction 100E2A of the aperture 100E2X and also parallel to the vertical direction 12D of the screen 10.

[0113] Next, the second substrate 200 of this example was fabricated by forming a second substrate-side light-shielding film 20BM on the second support substrate 210. The second substrate-side light-shielding film 20BM was positioned on the outer frame of the screen 10 and extended along the row direction (horizontal direction 11D) between two adjacent pixels 10P in the column direction (vertical direction 12D). The second substrate-side light-shielding film 20BM was not positioned between two adjacent pixels 10P in the row direction (it did not extend along the column direction between two adjacent pixels 10P in the row direction).

[0114] Furthermore, a second alignment film 420 was formed on the second substrate side light-shielding film 20BM. In a plan view, the second alignment film 420 was subjected to an alignment process so that the orientation direction 302LA of the liquid crystal molecules 302L on the second substrate 200 side, when no voltage is applied, is arranged parallel to the vertical direction 12D of the screen 10.

[0115] A liquid crystal cell was fabricated by arranging the first substrate 100 with the first alignment film 410 and the second substrate 200 with the second alignment film 420, which were prepared as described above, so that the first alignment film 410 and the second alignment film 420 faced each other, and bonding the two substrates together via a liquid crystal layer 300. Next, a first polarizing plate 510 having a first polarization axis 510A was placed on the first substrate 100 opposite to the liquid crystal layer 300, and a second polarizing plate 520 having a second polarization axis 520A was placed on the second substrate 200 opposite to the liquid crystal layer 300, such that in a plan view, the first polarization axis 510A and the second polarization axis 520A were orthogonal, and the second polarization axis 520A was orthogonal to the longitudinal direction 100E2A of the aperture 100E2X. The second polarization axis 520A was arranged parallel to the vertical direction 12D of the screen 10. A driver and a drive circuit system were also connected to the liquid crystal cell. Furthermore, a backlight system was placed on the back side of the first polarizing plate 510 to fabricate the liquid crystal display device 1 of this embodiment.

[0116] Here, as the liquid crystal material constituting the liquid crystal layer 300, a liquid crystal mixture exhibiting positive dielectric anisotropy and a nematic phase within a certain temperature range was used, to which a chiral dopant was added. Merck Electronics' "S-811" was used as the chiral dopant, and the twist pitch (p) of the liquid crystal molecules 300L, which were twist-oriented by the chiral dopant, was adjusted to be approximately 8 times the cell thickness d of the liquid crystal layer 300. That is, the thickness (d) of the liquid crystal layer 300 was 12.5% ​​of the above twist pitch (p).

[0117] In this example, in a plan view, the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 in the state without applied voltage was arranged parallel to the longitudinal direction 100E2A of the opening 100E2X (specifically, at an angle of 0°).

[0118] The liquid crystal display device 1 in this example exhibited minimal light leakage and sufficiently suppressed oblique color mixing. Furthermore, when the contrast was measured using a colorimeter BM-5A (manufactured by Topcon Techno House Co., Ltd.), the liquid crystal display device 1 in this example achieved a high display contrast of approximately 400 to 600. Moreover, its response speed was faster than that of the liquid crystal display device 1 in Example 2, which will be described later.

[0119] In this example, we also investigated by appropriately varying the birefringence Δn and cell thickness d (μm) of the liquid crystal molecule 300L. We found that when their product (Δn × d) satisfies equation (1) above, oblique color mixing was more sufficiently suppressed and the response speed was superior.

[0120] Furthermore, when we investigated liquid crystal display devices in which the first polarization axis 510A and the second polarization axis 520A were positioned 90° differently from the first polarization axis 510A and the second polarization axis 520A of Example 1-1, we obtained the same results as in Example 1-1.

[0121] (Examples 1-2) A liquid crystal display device 1 of Example 1-2, corresponding to Embodiment 1, was fabricated (see Figures 1 to 4). The liquid crystal display device 1 of this example had the same configuration as the liquid crystal display device 1 of Example 1-1, except that the twist pitch (p) of the 300L of liquid crystal molecules twist-oriented by the chiral dopant was 24% of the cell thickness (d).

[0122] In this example, the relationship between the occurrence of display defects and the driving voltage was examined for the liquid crystal display device 1. The results are shown in Table 1. Here, the presence or absence of a display defect was determined by whether or not discrination lines were observed in the display area of ​​the liquid crystal display device 1 when a predetermined voltage was applied between the first electrode 100E1 and the second electrode 100E2. In Table 1, "×" means that discrination lines were observed visually, and "〇" means that discrination lines were not observed visually.

[0123] Discrination lines are lines that arise due to the orientation of liquid crystal molecules and are visible as dark lines under normal display conditions. Because the locations where discrination lines occur are uneven, their presence reduces brightness and causes display unevenness.

[0124] [Table 1]

[0125] In Table 1, "Driving Voltage (%)" is the voltage applied between the first electrode 100E1 and the second electrode 100E2, and represents the maximum brightness (i.e., maximum transmittance T) in the liquid crystal display device 1. max This value is set to 100% when the voltage obtained is 100%. As shown in Table 1, when the voltage was increased, discrination lines were observed when the drive voltage exceeded 85%. This is thought to be due to the fact that applying a high voltage between the first electrode 100E1 and the second electrode 100E2 makes reverse twist orientation more likely to occur. Furthermore, there was hysteresis in the occurrence of this malfunction; when the voltage was increased, discrination lines were not observed until the drive voltage reached 85%, but once discrination lines appeared, it was necessary to lower the drive voltage to 70% to eliminate them. Reverse twist orientation is an orientation state in which the rotation direction of the liquid crystal molecules 300L is reversed from the normal direction.

[0126] (Example 2) A liquid crystal display device 1 of Example 2, corresponding to the liquid crystal display device 1 of Embodiment 2, was fabricated (see Figures 1, 4, and 5). The liquid crystal display device 1 of this example had the same configuration as the liquid crystal display device 1 of Example 1-1, except that the liquid crystal molecules 300L had negative dielectric anisotropy, and the orientation processing directions of the first alignment film 410 and the second alignment film 420 were 90° different from those of Example 1-1.

[0127] In this example, in a plan view, the orientation direction 301LA of the liquid crystal molecules 301L on the first substrate 100 in the state without applied voltage was perpendicular to the longitudinal direction 100E2A of the opening 100E2X (specifically, at an angle of 90°).

[0128] The liquid crystal display device 1 in this example also exhibited minimal light leakage, high display contrast, and sufficient suppression of oblique color mixing. Furthermore, the liquid crystal display device 1 in this example showed higher transmittance than the liquid crystal display device 1 in Example 1-1.

[0129] Furthermore, when we investigated a liquid crystal display device in which the first polarization axis 510A and the second polarization axis 520A were positioned 90° differently from the first polarization axis 510A and the second polarization axis 520A of Example 2, we obtained the same results as in Example 2.

[0130] (Example 3) A liquid crystal display device 1 of Example 3, corresponding to the liquid crystal display device 1 of Embodiment 3, was fabricated (see Figures 1, 4, and 6). The liquid crystal display device 1 of this example had the same configuration as the liquid crystal display device 1 of Example 1-1, except that the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side in the no-voltage state was 2-3°.

[0131] In this example, the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 was adjusted to 2-3° by performing the orientation treatment of the first alignment film 140 using the rubbing method with a rubbing alignment film (liquid crystal alignment material (SunEver) "SE" series manufactured by Nissan Chemical Corporation). The orientation treatment of the second alignment film 240 was the same as in Example 1-1.

[0132] The liquid crystal display device 1 in this example also exhibited minimal light leakage, high display contrast, and sufficient suppression of oblique color mixing. Furthermore, although the liquid crystal display device 1 in this example had slightly lower transmittance than the liquid crystal display device 1 in Example 1-1, it had a faster response speed.

[0133] Furthermore, the effect obtained was almost the same whether the rubbing process was performed from top to bottom in Figure 6 (resulting in a downward pre-tilt angle) or from bottom to top in Figure 6 (resulting in an upward pre-tilt angle).

[0134] (Example 4) A liquid crystal display device 1 of Example 4, corresponding to the liquid crystal display device 1 of Embodiment 4, was fabricated (see Figures 1, 4, and 7). The liquid crystal display device 1 of this example had the same configuration as the liquid crystal display device 1 of Example 2, except that the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 side in the no-voltage state was 2-3°.

[0135] In this example, the pre-tilt angle of the liquid crystal molecules 301L on the first substrate 100 was adjusted to 2-3° by performing the orientation treatment of the first alignment film 140 using a rubbing method with a rubbing alignment film (liquid crystal alignment material (SunEver) "SE" series manufactured by Nissan Chemical Corporation). The orientation treatment of the second alignment film 240 was the same as in Example 2.

[0136] The liquid crystal display device 1 in this example also exhibited minimal light leakage, achieved high display contrast, and sufficiently suppressed oblique color mixing. Furthermore, although the liquid crystal display device 1 in this example had slightly lower transmittance than the liquid crystal display device 1 in Example 2, it had a faster response speed.

[0137] Furthermore, the effect obtained was almost the same whether the rubbing process was performed from top to bottom in Figure 7 (resulting in a downward pre-tilt angle) or from bottom to top in Figure 7 (resulting in an upward pre-tilt angle).

[0138] While embodiments of the present disclosure have been described above, the present disclosure is not limited to the embodiments and their variations, and can be implemented in various forms and variations thereof without departing from its essence. Furthermore, the multiple components disclosed in the embodiments and their variations may be modified as appropriate. For example, some components from all the components shown in one embodiment or variation may be added to the components of another embodiment or variation, or some components from all the components shown in one embodiment or variation may be removed from the embodiment or variation.

[0139] Furthermore, the drawings schematically show each component in order to facilitate understanding of the invention, and the thickness, length, number, spacing, etc. of each component shown may differ from the actual dimensions due to the convenience of drawing creation. Also, the configuration of each component shown in the above embodiments is merely an example and is not particularly limiting, and it goes without saying that various modifications are possible within the scope that does not substantially deviate from the effects of this disclosure. [Explanation of Symbols]

[0140] 1, 1R: Liquid crystal display device 1P: Pixels 10: Screen 10CH1, 10CH2: Through-hole 10P:Picture element 10PB:Blue pixel 10PG: Green picture element 10PR: Red pigment 11D: Horizontal 12D: Vertical direction 20BM: Second substrate side light shielding film 100: First board 100E1: First electrode 100E2: Second electrode 100E2A, 100EAR: Longitudinal direction 100E2X, 100EXR: Opening 100ER: Electrode 100F: Insulating layer 100M, 100MR: Light shielding film 100T: Nonlinear element 110: First support substrate 120: Gate wiring layer 120L, 120LR: Gate wire 130: First insulating layer 150: Source wiring layer 150D: Drain electrode 150L, ​​150LR: Source wire 160: Second insulating layer 170: Color filter layer 170B, 170BR: Blue color filter 170G, 170GR: Green color filter 170R, 170RR: Red color filter 180: Flattening film 200:Second board 210:Second support board 300: Liquid crystal layer 300L, 300LR, 301L, 302L: Liquid crystal molecules 300LAR, 301LA, 301LAR, 302LA, 302LAR: Orientation direction 410: First orientation layer 420:Second alignment film 510: First polarizing plate 510A, 510AR: First polarization axis 520:Second polarizing plate 520A, 520AR: Second polarization axis 600, 600R: Spacer

Claims

1. It has multiple picture elements arranged in a matrix containing multiple rows and multiple columns, The device comprises, in order from the back side toward the observation surface side, a first substrate, a liquid crystal layer, and a second substrate. The first substrate has, in order from the back side toward the observation side, a first electrode, an insulating layer, and a second electrode having one longitudinal opening for each of the plurality of pixels that extends along the row or column direction of the plurality of pixels, and further comprises a plurality of nonlinear elements arranged corresponding to each pixel. The liquid crystal layer comprises liquid crystal molecules and a chiral dopant. In a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state where no voltage is applied is arranged parallel to or perpendicular to the longitudinal direction of the opening, in a liquid crystal display device.

2. The liquid crystal molecule has positive dielectric anisotropy, The liquid crystal display device according to claim 1, wherein, in a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state without applied voltage is arranged parallel to the longitudinal direction of the opening.

3. The liquid crystal molecule has negative dielectric anisotropy, The liquid crystal display device according to claim 1, wherein, in a plan view, the orientation direction of the liquid crystal molecules on the first substrate side in the state without applied voltage is arranged perpendicular to the longitudinal direction of the opening.

4. The liquid crystal display device according to any one of claims 1 to 3, wherein the thickness of the liquid crystal layer is 5% or more and less than 25% of the twist pitch of the liquid crystal molecules twist-oriented by the chiral dopant.

5. A liquid crystal display device according to any one of claims 1 to 3, wherein, in a plan view, the orientation direction of the liquid crystal molecules on the second substrate side in the state of no applied voltage is parallel to the orientation direction of the liquid crystal molecules on the first substrate side in the state of no applied voltage.

6. The product of the birefringence Δn of the liquid crystal molecule and the thickness d (μm) of the liquid crystal layer (Δn × d) is given by the following formula (1): [Math 1] The relation expressed by satisfies, The liquid crystal display device according to any one of claims 1 to 3, wherein the voltage applied between the first electrode and the second electrode is driven at 85% or less of the voltage at which maximum brightness is obtained in the liquid crystal display device.

7. In the state where no voltage is applied, the pre-tilt angle of the liquid crystal molecules on the first substrate side is 1° or more and 5° or less with respect to the main surface of the first substrate. The liquid crystal display device according to any one of claims 1 to 3, wherein the pre-tilt angle of the liquid crystal molecules on the second substrate side in the state of no applied voltage is substantially 0° with respect to the main surface of the second substrate.

8. The liquid crystal display device according to any one of claims 1 to 3, wherein the first substrate further comprises a color filter layer and a planarization film disposed on the liquid crystal layer side of the color filter layer.

9. The first substrate further comprises a longitudinally shaped light-shielding film arranged between the plurality of pixels, In a plan view, the longitudinal direction of the light-shielding film is arranged parallel to the longitudinal direction of the opening, as described in any one of claims 1 to 3.

10. The system further comprises a first polarizing plate having a first polarization axis and a second polarizing plate having a second polarization axis. The first polarizing plate is positioned on the back side of the first substrate. The second polarizing plate is positioned on the observation surface side of the second substrate. The first polarizing plate and the second polarizing plate are arranged so that the first polarization axis and the second polarization axis are perpendicular to each other. In a plan view, the second polarization axis is arranged parallel to or perpendicular to the longitudinal direction of the aperture, as described in any one of claims 1 to 3.

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