Liquid crystal display device

Abstract

A reflective or semi-transmissive liquid crystal display device of a lateral electric field mode capable of improving reflectivity can be provided. The liquid crystal display device comprises, in the following order: a first substrate; a first alignment layer; a liquid crystal layer, which comprises liquid crystal molecules that are horizontally aligned when no voltage is applied; a second alignment layer; a second substrate, which has a pixel electrode and a common electrode, and further comprises: a reflective layer, which is disposed on at least a portion of a pixel on the back side relative to the first alignment layer, the liquid crystal layer, the second alignment layer, the pixel electrode, and the common electrode, and the azimuthal anchoring energy of at least one of the first alignment layer and the second alignment layer is less than 1×10 ‑4 J / m 2 .

Description

Technical Field

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

[0002] A liquid crystal display device is a display device that uses a liquid crystal composition for display. Its typical display method is: a TFT substrate having a thin film transistor (TFT: Thin Film Transistor), irradiating light to a liquid crystal layer between a counter substrate arranged opposite to the TFT substrate, applying voltage to liquid crystal molecules contained in the liquid crystal layer to change the orientation state of the liquid crystal molecules, thereby controlling the amount of light transmission. When the voltage applied to the liquid crystal layer is less than the threshold voltage (including no voltage application), the orientation of the liquid crystal molecules in the liquid crystal layer is controlled mainly by the action of the alignment films respectively provided on the liquid crystal layer side of the TFT substrate and the counter substrate.

[0003] Liquid crystal display devices are roughly divided into reflective type and transmissive type according to the method of light transmission to the liquid crystal layer. Transmissive type liquid crystal display devices are equipped with a backlight unit, and display is performed by transmitting the light emitted from the backlight unit through the liquid crystal layer. Transmissive type liquid crystal display devices have a light source inside the device, so the visibility is good even in a darker environment. On the other hand, reflective type liquid crystal display devices have a reflective layer arranged on at least a part of the pixel, and the reflective layer reflects the incident light from the outside, and the reflected light is transmitted through the liquid crystal layer for display. Since reflective type liquid crystal display devices do not require a backlight unit, they can achieve low power consumption, thinness, and lightness. In addition, in recent years, not only the visibility indoors but also the visibility of external light are considered. As a liquid crystal display device that has the advantages of both reflective type and transmissive type, a semi-transmissive liquid crystal display device has been proposed.

[0004] As a technology related to a reflective liquid crystal display device and a semi-transmissive liquid crystal display device, for example, patent document Patent document 1 discloses a bistable nematic liquid crystal display device having a color filter and a reflector on the main substrate side, wherein a main substrate having a strongly anchored orientation film on the first substrate and a slave substrate having a weakly anchored orientation film on the second substrate are arranged with their orientation film sides facing each other, and has a liquid crystal unit formed by sandwiching a nematic liquid crystal layer between these orientation films. The liquid crystal display device is a liquid crystal display device that controls the arrangement of liquid crystal molecules in the liquid crystal layer to be in any one of the bistable states according to a driving voltage.

[0005] Patent document 2 discloses a reflective liquid crystal display device, which comprises: a liquid crystal, which is sealed on a pair of substrates arranged opposite to each other and contains a polymerizable component that is polymerized by light or heat; a reflective electrode, which is arranged on one of the above substrates; and a polymer layer, which is formed on the above reflective electrode by polymerizing the above polymerizable component while applying a voltage to the above liquid crystal, and gives a pretilt angle to the liquid crystal molecules.

[0006] Patent document 3 discloses a liquid crystal display device, which has a plurality of pixels, each of which has a signal electrode and a common electrode and is arranged in a matrix, each of which has a transmission portion and a reflection portion, and the pixel has a first liquid crystal orientation region and a second liquid crystal orientation region with different liquid crystal orientation directions, the first liquid crystal orientation region and the second liquid crystal orientation region are adjacent to each other in the pixel, and a boundary region in which the liquid crystal orientation directions of the first liquid crystal orientation region and the second liquid crystal orientation region continuously change is provided between the first liquid crystal orientation region and the second liquid crystal orientation region that are adjacent to each other, the first liquid crystal orientation region is wider than the transmission portion, and the second liquid crystal orientation region is narrower than the reflection portion.

[0007] Patent document 4 discloses a display device comprising: a plurality of segmented pixels, comprising a reflective electrode, an opposing electrode arranged opposite to the reflective electrode, a color filter arranged on the opposite side of the opposing electrode opposite to the reflective electrode; and a holding portion for holding a potential corresponding to a grayscale expression; and an inorganic light-emitting body arranged on the opposing electrode side relative to the color filter to irradiate light.

[0008] Prior art literature

[0009] Patent Literature

[0010] Patent Document 1: Japanese Patent Application Publication No. 2005-173209

[0011] Patent Document 2: Japanese Patent Application Publication No. 2003-177418

[0012] Patent Document 3: Japanese Patent Application Publication No. 2009-162837

[0013] Patent Document 4: International Publication No. 2020 / 230571 Summary of the invention

[0014] Technical Problems to be Solved by the Invention

[0015] In a reflective liquid crystal display device or a semi-transmissive liquid crystal display device that displays by reflecting light from the observation surface side at a reflective layer inside the device and transmitting the reflected light through a liquid crystal layer, the reflectivity of light is controlled by modulating the in-plane phase difference (hereinafter also referred to as phase difference) of the liquid crystal layer between 0 and 1 / 4 wavelength according to an applied voltage.

[0016] Here, liquid crystal display devices are roughly divided into the following two types according to the direction of application of the electric field for changing the orientation of the liquid crystal molecules in the liquid crystal layer. That is, as a first category, there is a longitudinal electric field mode in which an electric field is applied in the thickness direction (or out-of-plane direction) of the display device (liquid crystal layer). Examples of longitudinal electric field modes include TN (Twisted Nematic) mode and VA (Vertical Alignment) mode. In addition, as a second category, there is a transverse electric field mode in which an electric field is applied in the plane direction (or in-plane direction) of the display device (liquid crystal layer). Examples of transverse electric field modes include IPS (In-Plane Switching) mode and FFS (Fringe Field Switching) mode.

[0017] In the longitudinal electric field mode, the orientation of the liquid crystal molecules changes due to the uniform electric field generated between a pair of substrates sandwiching the liquid crystal layer. Therefore, the orientation of the liquid crystal molecules when a voltage is applied is also uniform within the pixel plane. Therefore, the phase difference △nd of the liquid crystal layer becomes the same within the plane, and the modulation width of the phase difference △nd of the liquid crystal layer is also large. Therefore, in the reflective liquid crystal display device and the semi-transmissive liquid crystal display device in the longitudinal electric field mode, sufficient reflectivity can be obtained.

[0018] On the other hand, in the transverse electric field mode, the orientation of the liquid crystal molecules changes due to the transverse electric field (particularly the fringe electric field in the FFS mode) generated between the common electrode and the pixel electrode provided on one of the pair of substrates sandwiching the liquid crystal layer. The transverse electric field mode will be described in more detail by taking a comparative liquid crystal display device as an example of an existing FFS mode liquid crystal display device. Fig.49 is a simulation result of calculating the alignment state of liquid crystal molecules in a liquid crystal display device of a comparative method. Fig.49 As shown, the liquid crystal display device 1R of the comparative embodiment includes: a first substrate 100 ; a liquid crystal layer 300 including liquid crystal molecules 310 ; and a second substrate 500 including an insulating substrate 510 , a common electrode 540 , and a pixel electrode 560 .

[0019] In the comparative liquid crystal display device 1R, the orientation of the liquid crystal molecules 310 is changed due to the fringe electric field generated between the common electrode 540 and the pixel electrode 560 provided on the second substrate 500. Fig.49As shown in the area surrounded by the dotted line, only the liquid crystal molecules 310 near the electrodes on the second substrate 500 side are driven, and the orientation of the liquid crystal molecules 310 when voltage is applied is also distributed in the thickness direction and the in-plane direction. Therefore, as a liquid crystal display device in a transverse electric field mode, the modulation width of the phase difference Δnd of the liquid crystal layer 300 of the comparative liquid crystal display device 1R is smaller than that in a longitudinal electric field mode. Therefore, the reflectivity of the existing reflective and semi-transmissive liquid crystal display devices in a transverse electric field mode (such as an FFS mode) is lower than that of the reflective and semi-transmissive liquid crystal display devices in a longitudinal electric field mode.

[0020] In none of the above-mentioned Patent Documents 1 to 4, an attempt to improve the reflectivity in a reflective or semi-transmissive liquid crystal display device in a transverse electric field mode is studied.

[0021] The present invention has been made in view of the above-mentioned current situation, and an object of the present invention is to provide a reflective or semi-transmissive liquid crystal display device in a lateral electric field mode capable of improving reflectivity.

[0022] Technical solutions for solving technical problems

[0023] (1) A liquid crystal display device according to one embodiment of the present invention comprises, in the following order: a first substrate; a first alignment layer; a liquid crystal layer comprising liquid crystal molecules that are horizontally aligned when no voltage is applied; a second alignment layer; a second substrate having a pixel electrode and a common electrode, and further comprising: a reflective layer disposed on at least a portion of a pixel on a back side relative to the first alignment layer, the liquid crystal layer, the second alignment layer, the pixel electrode, and the common electrode, wherein an azimuthal anchoring energy of at least one of the first alignment layer and the second alignment layer is less than 1×10 -4 J / m 2 .

[0024] (2) In addition, in a liquid crystal display device according to one embodiment of the present invention, in addition to the configuration of (1), the azimuthal anchoring energy of the first alignment layer is less than 1×10 -4 J / m 2 , the azimuthal anchoring energy of the second alignment layer is 1×10 -4 J / m 2 above.

[0025] (3) In addition, in a liquid crystal display device according to one embodiment of the present invention, in addition to the configuration of (2), the azimuthal anchoring energy of the first alignment layer is less than 1×10 -5 J / m 2 .

[0026] (4) In addition, in a liquid crystal display device according to one embodiment of the present invention, based on the structure of (2) or (3), the pixel has a reflective area where the reflective layer is provided and a transmissive area where the reflective layer is not provided, and the phase difference of the liquid crystal layer in the transmissive area is greater than 220nm and less than 320nm.

[0027] (5) In addition, a liquid crystal display device according to one embodiment of the present invention further includes a λ / 4 plate based on the structure of (2), (3) or (4), wherein the orientation direction of the first orientation layer is parallel to the orientation direction of the second orientation layer, and the phase difference of the liquid crystal layer in the area overlapping with the reflective layer is greater than 80 nm and less than 180 nm.

[0028] (6) In addition, in the liquid crystal display device of one embodiment of the present invention, based on the configuration of (1), the azimuthal anchoring energy of the first alignment layer 200 is less than 1×10 -4 J / m 2 , the azimuthal anchoring energy of the second alignment layer is 1×10 -4 J / m 2 above.

[0029] (7) In addition, in the liquid crystal display device of one embodiment of the present invention, based on the configuration of (6), the second alignment layer 400 preferably has an azimuthal anchoring energy of less than 1×10 -5 J / m 2 .

[0030] (8) In addition, a liquid crystal display device according to one embodiment of the present invention further includes a λ / 4 plate based on the structure of (6) or (7), wherein the orientation direction of the first orientation layer is parallel to the orientation direction of the second orientation layer, and the phase difference of the liquid crystal layer in the area overlapping with the reflective layer is greater than 130 nm and less than 230 nm.

[0031] (9) In addition, a liquid crystal display device according to one embodiment of the present invention further includes a λ / 4 plate based on the structure of (1), (2), (3), (4), (5), (6), (7) or (8), wherein the orientation direction of the first orientation layer is parallel to the orientation direction of the second orientation layer, and the phase difference of the liquid crystal layer in the region overlapping with the reflective layer is greater than 130 nm and less than 145 nm.

[0032] (10) In a liquid crystal display device according to one embodiment of the present invention, based on the structure of (1), (2), (3), (4), (6) or (7), the orientation direction of the first orientation layer is not parallel to the orientation direction of the second orientation layer, and the phase difference of the liquid crystal layer in the area overlapping with the reflective layer is greater than 240nm and less than 260nm.

[0033] (11) In addition, a liquid crystal display device according to one embodiment of the present invention is based on the structure of (1), (7), (8), (9) or (10), wherein the second substrate further includes a color filter.

[0034] (12) In addition, a liquid crystal display device according to one embodiment of the present invention is based on the structure of (11) above, wherein at least one of the first orientation layer and the second orientation layer contains a polymer having the following groups: at least one first photofunctional group selected from cyclobutyl, azophenyl, chalcone, cinnamate, coumarin, stilbene, phenolic ester and phenylbenzoate; at least one second photofunctional group selected from acrylate, methacrylate, cinnamoyl, coumarin, vinyl, allyl, styryl and maleimide, and the liquid crystal layer contains an additive having at least one group selected from acrylate, methacrylate, cinnamoyl, coumarin, vinyl, allyl, styryl and maleimide.

[0035] (13) A liquid crystal display device according to one embodiment of the present invention further includes a λ / 2 plate based on the structure of (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11) or (12).

[0036] (14) A liquid crystal display device according to one embodiment of the present invention further includes a λ / 4 plate based on the structure of (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12) or (13).

[0037] (15) In a liquid crystal display device according to one embodiment of the present invention, based on the configuration of (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13) or (14), the pixel has a plurality of sub-pixels.

[0038] (16) In a liquid crystal display device according to one embodiment of the present invention, the pixel has a storage circuit based on the structure of (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13), (14) or (15).

[0039] Beneficial Effects

[0040] According to the present invention, a reflective or semi-transmissive liquid crystal display device in a lateral electric field mode capable of improving reflectivity can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 1 is a schematic plan view showing a liquid crystal display device according to Embodiment 1.

[0042] Figure 2 is along Figure 1 Schematic diagram of the cross section of line A1-A2 in FIG.

[0043] Figure 3 This is a simulation result of calculating the alignment state of liquid crystal molecules in the liquid crystal display device of Embodiment 1.

[0044] Figure 4 1 is a schematic plan view showing a liquid crystal display device according to Embodiment 2.

[0045] Figure 5 is along Figure 4 Schematic diagram of the cross section of line A1-A2 in FIG.

[0046] Figure 6 1 is a schematic plan view showing a liquid crystal display device according to Embodiment 3.

[0047] Figure 7 is along Figure 6 Schematic diagram of the cross section of line A1-A2 in .

[0048] Figure 8 1 is a schematic plan view showing a liquid crystal display device according to Modification 1.

[0049] Fig. 9 is along Figure 8 Schematic diagram of the cross section of line B1-B2 in FIG.

[0050] Fig.10 It is a diagram showing the transmittance of the liquid crystal layer in the transmission region in Modifications 1-1 and 1-2 and a conventional FFS mode transmissive liquid crystal display device.

[0051] Fig.11 is a cross-sectional schematic diagram of a liquid crystal display device according to a third variation, showing the embodiment The case where a λ / 4 plate is configured instead of a λ / 2 plate.

[0052] Fig.12 This is a diagram showing an example of the transmission axis azimuth of the polarizing plate, the alignment azimuths of the first alignment layer and the second alignment layer, and the slow axis azimuth of the λ / 4 plate of the liquid crystal display device of Modification 3.

[0053] Fig.13 This is a graph in which the reflectance of the liquid crystal display device of Modification 3-1 and the conventional FFS mode reflective liquid crystal display device is plotted against the phase difference of the liquid crystal layer.

[0054] Fig.14 It is a schematic cross-sectional view of a liquid crystal display device according to variation 4.

[0055] Fig.15 This is a diagram showing an example of the transmission axis azimuth of the polarizing plate of the liquid crystal display device according to Modification 4, and the alignment azimuths of the first alignment layer and the second alignment layer.

[0056] Fig.16 This is an example of a schematic cross-sectional view of a liquid crystal display device according to Modification 5, and shows a case where the color filter layer is arranged on the first substrate side in Embodiment 1.

[0057] Fig.17 is an example of a cross-sectional schematic diagram of a liquid crystal display device of Modification Example 8, showing an embodiment configured in the reverse order The situation of the components.

[0058] Fig.18 It is a VR characteristic curve diagram showing a liquid crystal display device in a lateral electric field mode having a weak anchor alignment layer.

[0059] Fig.19 This is a schematic diagram for explaining the display of half-gray scales by the liquid crystal display device according to the tenth modification.

[0060] Fig. 20 A diagram for explaining white display and black display in a graph showing VR characteristics of a liquid crystal display device.

[0061] Fig.21 Schematic diagram for explaining pixels of a liquid crystal display device according to Modification 10.

[0062] Fig. 22 This is a schematic diagram for explaining the grayscale of pixels in a liquid crystal display device according to Modification 10.

[0063] Fig.23 This is a circuit diagram simply showing an example of the circuit configuration of a pixel of a liquid crystal display device according to Modification 10.

[0064] Fig.24 This is a circuit diagram specifically showing an example of the circuit configuration of a pixel of a liquid crystal display device according to Modification 10.

[0065] Fig.25 This is an example of a schematic waveform diagram of each signal voltage used for driving the liquid crystal display device of Modification 10 and a voltage applied to the liquid crystal layer.

[0066] Fig.26 This is a circuit diagram showing an example of a circuit configuration of a pixel of a liquid crystal display device according to Modification 10.

[0067] Fig. 27 This is an example of a schematic waveform diagram of each signal voltage used for driving the liquid crystal display device of Modification 10 and a voltage applied to the liquid crystal layer.

[0068] Fig.28 1 is a schematic plan view showing a liquid crystal display device according to Example 1.

[0069] Fig.29 1 is a schematic cross-sectional view showing a liquid crystal display device according to Example 1.

[0070] Fig.30 It is a diagram showing the transmission axis orientation of the polarizing plate and the orientation orientations of the first orientation layer and the second orientation layer of the liquid crystal display devices of Examples 1 and 2.

[0071] Fig.31 1 is a schematic cross-sectional view showing a liquid crystal display device according to Example 2.

[0072] Fig.32 1 is a schematic cross-sectional view showing a liquid crystal display device according to Example 3.

[0073] Fig.33 The diagram shows the transmission axis orientation of the polarizing plate, the orientation orientations of the first orientation layer and the second orientation layer, and the slow axis orientation of the λ / 2 plate in the liquid crystal display devices of Examples 3 and 4.

[0074] Fig.34 1 is a schematic cross-sectional view showing a liquid crystal display device of Example 4.

[0075] Fig.35 1 is a schematic cross-sectional view showing a liquid crystal display device of a comparative example.

[0076] Fig.36 The diagram shows the transmission axis azimuth of the polarizing plate, the alignment azimuths of the first alignment layer and the second alignment layer, and the slow axis azimuth of the λ / 2 plate in a liquid crystal display device of a comparative example.

[0077] Fig.37This is a simulation result of calculating the alignment state of liquid crystal molecules in the liquid crystal display device of the comparative example.

[0078] Fig.38 This is a simulation result of calculating the alignment state of liquid crystal molecules in the liquid crystal display device of Example 3.

[0079] Fig.39 This is a simulation result of calculating the alignment state of liquid crystal molecules in the liquid crystal display device of Example 4.

[0080] Fig.40 This is a diagram showing simulation results for calculating the magnitude of the displacement angle of the liquid crystal molecules in the liquid crystal display devices of Examples 3 and 4 and the comparative example with respect to the thickness direction of the liquid crystal layer.

[0081] Fig.41 It is a graph showing VR characteristics of the liquid crystal display devices of Examples 3 and 4 and the comparative example.

[0082] Fig.42 1 is a schematic cross-sectional view showing a liquid crystal display device of Example 5.

[0083] Fig.43 The diagram shows the transmission axis orientation of the polarizing plate, the orientation orientations of the first orientation layer and the second orientation layer, and the slow axis orientation of the λ / 2 plate in the liquid crystal display device of Example 5.

[0084] Fig.44 1 is a schematic cross-sectional view showing a liquid crystal display device of Example 6.

[0085] Fig.45 The diagram shows the transmission axis orientation of the polarizing plate, the orientation orientations of the first orientation layer and the second orientation layer, and the slow axis orientation of the λ / 2 plate in the liquid crystal display device of Example 6.

[0086] Fig.46 This is an example A graph showing VR characteristics of liquid crystal display devices according to a comparative example and a reference example.

[0087] Fig.47 1 is a schematic cross-sectional view showing a liquid crystal display device of Example 7.

[0088] Fig.48 is a graph showing VR characteristics of an MIP type liquid crystal display device.

[0089] Fig.49 This is a simulation result of calculating the alignment state of liquid crystal molecules in a liquid crystal display device of a comparative method. DETAILED DESCRIPTION

[0090] The following describes the embodiments of the present invention. The present invention is not limited to the contents described in the following embodiments, and can be appropriately designed and changed within the scope of the configuration of the present invention. In addition, the various configurations described in the embodiments can be appropriately combined or changed within the scope of the present invention.

[0091] (Implementation Method 1)

[0092] Figure 1 It is a schematic plan view of a liquid crystal display device according to Embodiment 1. Figure 2 is along Figure 1 Schematic diagram of the cross section of line A1-A2 in . Figure 3 is a simulation result of calculating the alignment state of the liquid crystal molecules in the liquid crystal display device of Embodiment 1. Figure 1 As shown, the liquid crystal display device 1 of this embodiment includes: a plurality of gate lines 501, which extend in parallel with each other on the second substrate; and a plurality of source lines 502, which extend in parallel with each other in a direction intersecting with each gate line 501 through an insulating film. The plurality of gate lines 501 and the plurality of source lines 502 are formed into a grid shape as a whole to divide each pixel 1PX. A thin film transistor (TFT: Thin Film Transistor) 503 is arranged at the intersection of each gate line 501 and each source line 502. A pixel electrode 560 is arranged in each area surrounded by two adjacent gate lines 501 and two adjacent source lines 502.

[0093] The TFT 503 is composed of a gate electrode 505 extending from a gate line 501, a source electrode 506 extending from a source line 502, a semiconductor layer 507, and a drain electrode 508 disposed on the semiconductor layer 507 and arranged opposite to the source electrode 506. The drain electrode 508 is electrically connected to the pixel electrode 560 via an insulating film 550, a common electrode 540, a planarizing film 530, and a contact hole 509 disposed in the color filter layer 1CF. In addition, the reflective layer 520 is not disposed at the connection portion between the drain electrode 508 and the pixel electrode 560.

[0094] like Figure 2 and Figure 3 As shown, the liquid crystal display device 1 of this embodiment includes, from the observation side to the back side, a linear polarizer 10, a λ / 2 plate 11, a first substrate 100, a first alignment layer 200, a liquid crystal layer 300 including liquid crystal molecules 310 aligned horizontally when no voltage is applied, a second alignment layer 400, and a second substrate 500. The second substrate 500 is a TFT substrate having TFTs 503, and the first substrate 100 is an opposing substrate arranged opposite to the second substrate 500.

[0095] The azimuthal anchoring energy of the first alignment layer 200 is less than 1×10 -4 J / m2 , the azimuthal anchoring energy of the second alignment layer 400 is 1×10 -4 J / m 2 Above. Below, the azimuth anchoring energy is less than 1×10 -4 J / m 2 The orientation layer is called a weakly anchored orientation layer, and the azimuthal anchoring energy is 1×10 -4 J / m 2 The above alignment layer is called a strongly anchored alignment layer.

[0096] The second substrate 500 includes, from the back side toward the observation side, an insulating substrate 510, a reflective layer 520 provided on the entire surface of the pixel 1PX, a color filter layer 1CF, a planarization film 530, a common electrode 540, an insulating film 550, and a pixel electrode 560 provided with a slit. In the liquid crystal display device 1, in the reflective region R provided with the reflective layer 520, incident light from the observation side is reflected by the reflective layer 520, and the reflected light is displayed through the liquid crystal layer 300. That is, the liquid crystal display device 1 of this embodiment is a reflective liquid crystal display device of a transverse electric field mode (specifically, an FFS mode).

[0097] In the liquid crystal display device 1 of the present embodiment, which is a reflective liquid crystal display device of the FFS mode, in a no-voltage application state in which no voltage is applied between the common electrode 540 and the pixel electrode 560, the linearly polarized light that passes through the linear polarizer 10 from the observation surface side to the back surface side passes through the λ / 2 plate 11 and the horizontally aligned liquid crystal layer 300, becomes circularly polarized light and reaches the reflective layer 520. The light reaching the reflective layer 520 is converted into opposite circularly polarized light in the reflective layer 520, passes through the liquid crystal layer 300 and the λ / 2 plate 11 in the reverse order to that at the time of incidence, becomes linearly polarized light orthogonal to the incident linear polarized light, and realizes a dark state.

[0098] On the other hand, in a voltage application state where a voltage is applied between the common electrode 540 and the pixel electrode 560, the orientation of the liquid crystal molecules 310 of the liquid crystal layer 300 changes, and the in-plane phase difference of the liquid crystal layer 300 changes. The linearly polarized light that has passed through the linear polarizer 10 passes through the λ / 2 plate 11 and the liquid crystal layer 300, and ideally becomes linearly polarized light, and reaches the reflective layer 520. The light that has reached the reflective layer 520 is reflected by the reflective layer 520, passes through the liquid crystal layer 300 and the λ / 2 plate 11 in the reverse order to the incident light, and becomes linearly polarized light parallel to the incident linearly polarized light, thereby achieving a bright state.

[0099] However, in the existing FFS mode reflective liquid crystal display device, the phase difference Δnd of the liquid crystal layer under the voltage application state cannot be fully obtained, and the light reaching the reflective layer through the phase difference layer and the liquid crystal layer is not the ideal linear polarized light, but is close to elliptically polarized light. Therefore, the light reflected by the reflective layer is also close to elliptically polarized light, and sufficient reflectivity cannot be obtained.

[0100] Taking the comparative liquid crystal display device 1R as an example, the relationship between the anchoring force of the alignment layer and the reflectivity is described. The comparative liquid crystal display device 1R has a strongly anchored alignment layer between the first substrate 100 and the liquid crystal layer 300 and between the second substrate 500 and the liquid crystal layer 300. In the comparative liquid crystal display device 1R, as shown in FIG. Fig.49 As shown in the area surrounded by the dotted line, the maximum displacement area of ​​the liquid crystal molecules 310 exists on the second substrate 500 side (the substrate side provided with the common electrode 540 and the pixel electrode 560) relative to the thickness of the liquid crystal layer 300, and the liquid crystal molecules 310 on the first substrate 100 side are difficult to move compared to the second substrate 500 side. As a result, the modulation width of the phase difference Δnd of the liquid crystal layer 300 cannot be sufficiently increased in the plane, and it is difficult to obtain a high reflectivity.

[0101] On the other hand, in the liquid crystal display device 1 of this embodiment, the first alignment layer 200 is a weakly anchored alignment layer. By adopting such a method, the liquid crystal molecules 310 can be easily moved not only on the second substrate 500 side where the common electrode 540 and the pixel electrode 560 are provided, but also on the first substrate 100 side, and the liquid crystal molecules 310 can be moved in a wider area. As a result, Figure 3 As shown in the area surrounded by the dotted line, the liquid crystal molecules 310 are rotated in a wider area than the liquid crystal display device 1R of the comparative method, so that the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be made larger relatively uniformly in the plane, and a high reflectivity can be achieved. In addition, the optimal cell thickness for providing the maximum reflectivity can be set to be thin. This is also advantageous in terms of response speed.

[0102] Thus, in this embodiment, the modulation width of Δnd of the liquid crystal layer 300 is increased, and the light reaching the reflective layer 520 is made close to linear polarization, thereby improving the reflectivity. In addition, as described in Japanese Patent Application Laid-Open No. 11-142836, it is known that the polarization state on the reflective layer 520 is a bright state if it is linear polarization in any direction, and a dark state if it is right or left circular polarization.

[0103] In addition, the liquid crystal display device 1 of the present embodiment is a liquid crystal display device in a transverse electric field mode, and therefore, it can also carry the function of an embedded (In-Cell) type touch panel that is difficult to carry in a liquid crystal display device in a longitudinal electric field mode. In a liquid crystal display device with an embedded touch panel, the electrodes of the pixels provided in the display panel are also used as touch panel (Touch Panel, hereinafter referred to as TP) electrodes. For example, a common electrode that can be divided to apply a common voltage to each pixel is used as a common electrode during the writing period of the display signal (data signal) written as a display signal to each pixel, and functions as a TP electrode during the sensing period of at least one of the contact and proximity of the indicator to the display area. On the other hand, in a liquid crystal display device in a longitudinal electric field mode, since the entire surface common electrode is arranged on the first substrate side, the common electrode becomes a shield and cannot be sensed. In order to embed the touch panel in the longitudinal electric field mode, it is necessary to pattern and stack multiple electrodes for sensing on the first substrate side in addition to the common electrode, and the liquid crystal element becomes thicker and more complicated.

[0104] Hereinafter, this embodiment will be described in detail.

[0105] The liquid crystal display device 1 includes a gate driver electrically connected to the gate line 501, a source driver electrically connected to the source line 502, and a controller. The gate driver sequentially supplies a scanning signal to the gate line 501 according to the control of the controller. At the moment when the TFT 503 is in a voltage-applied state by the scanning signal, the source driver 300 provides a data signal to the source line 502 based on the control of the controller. The pixel electrode 560 is set to a potential corresponding to the data signal supplied by the corresponding TFT 503, and a fringe electric field is generated between the common electrode 540 and the pixel electrode 560, so that the liquid crystal molecules 310 of the liquid crystal layer 300 rotate. In this way, the magnitude of the voltage applied between the common electrode 540 and the pixel electrode 560 is controlled, so that the delay of the liquid crystal layer 300 changes, and the transmission or non-transmission of light is controlled.

[0106] A first alignment layer 200 and a second alignment layer 400 are respectively arranged between the first substrate 100 and the liquid crystal layer 300 and between the second substrate 500 and the liquid crystal layer 300, and the first alignment layer 200 and the second alignment layer 400 have the function of controlling the alignment of the liquid crystal molecules 310 contained in the liquid crystal layer 300. The first alignment layer 200 and the second alignment layer 400 respectively have the function of aligning the liquid crystal molecules 310 in the liquid crystal layer 300 substantially parallel to the respective principal surfaces of the first substrate 100 and the second substrate 500 when no voltage is applied to the liquid crystal layer 300 (when the voltage applied to the liquid crystal layer 300 is less than the threshold voltage). Here, the alignment of the liquid crystal molecules substantially parallel to the principal surface of the substrate means that the pre-tilt angle of the liquid crystal molecules is 0 to 5°, preferably 0 to 2°, and more preferably 0 to 1° relative to the principal surface of the substrate. The pre-tilt angle of the liquid crystal molecules refers to the angle at which the long axis of the liquid crystal molecules is tilted relative to the principal surface of each substrate when no voltage is applied to the liquid crystal layer.

[0107] The first alignment layer 200 preferably has an azimuthal anchoring energy of less than 1×10 -5 J / m 2 By adopting such a method, the liquid crystal molecules 310 on the first substrate 100 side become easier to move, and the liquid crystal molecules 310 can be moved in a wider area. As a result, the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be further increased, and the reflectivity can be further improved. In addition, the optimal cell thickness for providing the maximum reflectivity can be set to be thinner.

[0108] The lower limit of the orientation angle anchoring energy of the first orientation layer 200 is not particularly limited, and is, for example, 1×10 -8 J / m 2 above.

[0109] In addition, the second orientation layer 400 of the present embodiment is a strongly anchored orientation layer. Since the second substrate 500 of the present embodiment has a common electrode 540 and a pixel electrode 560, the electric field strength on the second substrate 500 side is stronger than the electric field strength on the first substrate 100 side. In the present embodiment, by providing the second orientation layer 400 as a strongly anchored orientation layer on the second substrate 500 side with a stronger electric field strength, sintering can be improved. In addition, since the orientation restoring force is improved, the response speed of the liquid crystal molecules 310 can also be improved. The lower limit value of the orientation angle anchoring energy of the second orientation layer 400 can be 1×10 -3 J / m 2 above.

[0110] The upper limit of the orientation angle anchoring energy of the second orientation layer 400 is not particularly limited, for example, 1 J / m 2 the following.

[0111] The first alignment layer 200 and the second alignment layer 400 are respectively in contact with the liquid crystal layer 300. In this specification, "azimuthal anchoring energy of an alignment layer" refers to the azimuthal anchoring energy of a surface where the alignment layer contacts the liquid crystal layer (the interface between the two).

[0112] The azimuthal anchoring energy can be calculated by various known methods such as the torque balance method, the Neel domain wall method, calculation from the electric field response threshold, calculation from the rotating magnetic field, etc. In addition, the azimuthal anchoring energy described in this specification is calculated using the calculation method from the electric field response threshold.

[0113] The alignment restraining forces of the weakly anchored alignment layer and the strongly anchored alignment layer restraining the alignment direction of the liquid crystal molecules 310 are different from each other.

[0114] When the voltage applied between the common electrode 540 and the pixel electrode 560 becomes greater than the threshold value, the liquid crystal molecules 310 on the weakly anchored alignment layer side are released from the constraints of the weakly anchored alignment layer. In addition, the alignment direction of the liquid crystal molecules 310 changes from the initial alignment direction in a plane parallel to the surfaces of the first substrate 100 and the second substrate 500 according to the voltage applied between the common electrode 540 and the pixel electrode 560. The weakly anchored alignment layer forms a smooth interface (liquid interface) at the interface with the liquid crystal layer 300.

[0115] In contrast, the liquid crystal molecules 310 on the strongly anchored orientation layer side maintain their long axis directions roughly consistent with the initial orientation direction in a plane parallel to the surfaces of the first substrate 100 and the second substrate 500 even when a voltage above the threshold (for example, a white voltage) is applied between the common electrode 540 and the pixel electrode 560.

[0116] Therefore, when a voltage is applied between the common electrode 540 and the pixel electrode 560, on the weakly anchored orientation layer side of the liquid crystal layer 300, the orientation direction of the liquid crystal molecules 310 changes due to the orientation restriction force generated by the weakly anchored orientation layer. In contrast, on the strongly anchored orientation layer side of the liquid crystal layer 300, the liquid crystal molecules 310 roughly maintain their orientation direction while being subject to the orientation restriction force generated by the strongly anchored orientation layer.

[0117] In addition, in this specification, the term "weak anchoring" is used, which can also be referred to as zero-plane anchoring, lubricated interface, etc. The interface between the weakly anchored alignment layer and the liquid crystal layer forms a smooth interface with almost no anchoring, such as a liquid layer or gel layer, a low alignment order layer, or an ultra-low viscosity layer.

[0118] The strongly anchored alignment layer is formed by performing an alignment treatment. In addition to being formed by performing an alignment treatment, the weakly anchored alignment layer can also be formed without performing an alignment treatment. Specifically, the strongly anchored alignment layer can be a rubbed alignment layer that has been subjected to a rubbing treatment, or a photo-aligned layer that has been subjected to a photo-aligned treatment. The weakly anchored alignment layer can be a rubbed alignment layer, a photo-aligned layer, or an untreated alignment layer that has not been subjected to an alignment treatment.

[0119] The rubbing orientation layer is obtained, for example, by forming an orientation layer material containing a rubbing orientation layer polymer on a substrate, rotating a rubbing roller wound with a rubbing cloth made of rayon, cotton, etc., while keeping the rotation speed and the distance between the rubbing roller and the substrate constant, moving a workbench carrying the substrate formed with the orientation layer material, and rubbing the surface of the film containing the rubbing orientation layer polymer in a predetermined direction (rubbing method). By changing the conditions of the rubbing treatment, the azimuthal anchoring energy of the orientation layer can be adjusted to form a strongly anchored orientation layer and a weakly anchored orientation layer.

[0120] Generally, the friction strength L is expressed by the following formula.

[0121] L=N×a×{1+(2×π×r×n)} / (60×v)

[0122] Here, N is the number of frictions, a is the length of the portion where the friction cloth contacts the substrate, r is the radius of the friction roller, n is the rotation speed of the friction roller, and v is the table moving speed. The radius of the friction roller is determined by the design of the device. For example, by reducing the rotation speed of the friction roller and reducing the amount of pressure to shorten the length of the portion where the friction cloth contacts the substrate, a weakly anchored alignment layer can be formed.

[0123] In addition, by using a rubbed alignment layer polymer containing at least one of a linear or branched alkyl group having 2 to 20 carbon atoms and a polyalkylene oxide group such as polyethylene glycol or polypropylene alcohol, a weakly anchored rubbed alignment layer can be formed.

[0124] In addition, for example, by using a rubbed alignment layer polymer containing at least one structure represented by the following chemical formulas (D1) to (D6), a strongly anchored rubbed alignment layer can be formed.

[0125] [Chemistry 1]

[0126]

[0127] Examples of the rubbed alignment layer polymer include polyimide, etc. The rubbed alignment layer polymer may be one type or two or more types.

[0128] The photo-alignment layer is obtained, for example, by forming an alignment film material containing a photo-alignment polymer having a photo-functional group on a substrate, and irradiating the film with polarized ultraviolet light to generate anisotropy on the surface of the film containing the photo-alignment polymer (photo-alignment method). By changing the conditions and material structure of the photo-alignment treatment, the azimuthal anchoring energy of the alignment layer can be adjusted to form a strongly anchored alignment layer and a weakly anchored alignment layer.

[0129] Furthermore, for example, a weakly anchored photo-alignment layer can be formed by using a photo-alignment polymer containing at least one of a linear or branched alkyl group having 2 to 20 carbon atoms and a polyalkylene oxide group such as polyethylene glycol and polypropylene alcohol.

[0130] Furthermore, for example, by using a photo-alignment polymer having at least one structure represented by the above chemical formulas (D1) to (D6), a strongly anchored photo-alignment layer can be formed.

[0131] As the above-mentioned photo-alignment polymer, for example, a photo-alignment polymer having at least one photo-functional group selected from cyclobutyl, azophenyl, chalcone, cinnamate, coumarin, stilbene, phenolic ester and phenyl benzoate can be cited. The photo-alignment polymer contained in the photo-alignment layer can be one or more. The photo-functional group of the photo-alignment polymer can be present in the main chain of the polymer, in the side chain of the polymer, or in both the main chain and the side chain of the polymer.

[0132] The photoreaction type of the above-mentioned photo-orientation polymer is not particularly limited, and preferred examples of photodegradable polymers, phototransfer polymers (preferably photo-Fries rearrangement polymers), photoisomerization polymers, photodimerization polymers and photocrosslinking polymers can be cited. These methods can be used alone or in combination. Among them, from the viewpoint of orientation stability, photodegradable polymers having a reaction wavelength (main sensitive wavelength) near 254 nm and phototransfer polymers having a reaction wavelength (main sensitive wavelength) near 254 nm are particularly preferred. Photoisomerization polymers and photodimerization polymers having photofunctional groups in the side chains are also preferred.

[0133] The main chain structure of the photo-alignment polymer is not particularly limited, and preferred examples include a polyamic acid structure, a polyimide structure, a poly(meth)acrylic acid structure, a polysiloxane structure, a polyethylene structure, a polystyrene structure, and a polyolefin structure.

[0134] The untreated alignment layer is obtained, for example, by forming an alignment film material containing an alignment film polymer on a substrate. Examples of the alignment film polymer include polyimide and polyhexyl methacrylate. The alignment film polymer contained in the untreated alignment layer may be one type or two or more types.

[0135] In addition, examples of the alignment film polymer contained in the untreated alignment layer include polymers described in International Publication No. 2017 / 034023 in addition to polyimide and polyhexyl methacrylate, and among these, polyalkylene oxides such as polyethylene glycol and polypropylene glycol are preferred.

[0136] The first orientation layer 200 as a weakly anchored orientation layer preferably includes a polymer having the following groups: at least one first photofunctional group selected from cyclobutyl, azophenyl, chalcone, cinnamate, coumarin, stilbene, phenolic ester and phenylbenzoate; at least one second photofunctional group selected from acrylate (acryloyl), methacrylate (methacryloyl), cinnamoyl, coumarin, vinyl, allyl, styrene and maleimide, and the liquid crystal layer 300 includes an additive having at least one group selected from acrylate (acryloyl), methacrylate (methacryloyl), cinnamoyl, coumarin, vinyl, allyl, styrene and maleimide.

[0137] In this manner, a polymer having a first photofunctional group and a second photofunctional group is subjected to a photo-orientation treatment to form a strongly anchored orientation layer, and then, by additional irradiation from the observation side of the liquid crystal panel, the second photofunctional group reacts with the additive contained in the liquid crystal layer 300 and weakens the anchoring force imparted by the first photofunctional group, thereby forming a weakly anchored orientation layer.

[0138] The polymer having the first photofunctional group and the second photofunctional group preferably has a structure represented by the following chemical formula (A).

[0139] [Chemistry 2]

[0140]

[0141] (Where R 1 , R 2 , R 3 and R 4 Each independently represents a hydrogen atom or a hydrocarbon group, X 1 represents a tetravalent group having a cyclobutyl group, an azophenyl group, a chalcone group, a cinnamate group, a coumarin group, a stilbene group, a phenolic ester group or a phenylbenzoate group, and Y 1 represents a divalent group having an acrylate group, a methacrylate group, a cinnamoyl group, a coumarin group, a vinyl group, an allyl group, a styryl group, or a maleimide group. )

[0142] In the above chemical formula (A), R 1 , R 2 , R 3 and R 4Each independently represents a hydrogen atom or a hydrocarbon group having 1 to 3 carbon atoms.

[0143] The first photofunctional group is a photo-alignment functional group. From the viewpoint of orientation stability, the polymer having the first photofunctional group and the second photofunctional group preferably has a cyclobutyl group as the first photofunctional group on the main chain. In addition, the first photofunctional group may be present in the main chain of the polymer, may be present in the side chain, or may be present in both the main chain and the side chain.

[0144] The second photofunctional group is a polymerizable functional group. From the viewpoint of reactivity, the polymer having the first photofunctional group and the second photofunctional group preferably has a (meth)acrylate group as the second photofunctional group. The acrylate group and the methacrylate group listed as the second photofunctional group may be an acryloyloxy group and a methacryloyloxy group, respectively. In addition, the second photofunctional group may be present in the main chain of the polymer, in the side chain, or in both the main chain and the side chain, but preferably in the side chain.

[0145] The reaction wavelengths of the first photofunctional group and the second photofunctional group are not particularly limited, but are preferably different wavelengths from each other.

[0146] The liquid crystal layer 300 may contain one type of additive or two or more types of additives.

[0147] The amount of the additive introduced is preferably 0.1 to 10% by weight, more preferably 0.2 to 5% by weight, based on the entire material of the liquid crystal layer 300 (liquid crystal material).

[0148] The above-mentioned additive preferably contains an alkyl group. By adopting such a method, the anchoring force can be weakened. As the alkyl group contained in the additive, an alkyl group having 2 to 20 carbon atoms is preferred, and an alkyl group having 4 to 16 carbon atoms is particularly preferred. In addition, the alkyl group contained in the additive may be a linear structure, a branched structure, or a cyclic structure. An additive having a plurality of alkyl groups with different carbon atoms in the molecular structure is also preferred.

[0149] The specific types of the above-mentioned additives are not particularly limited, and preferred examples include unsaturated fatty acid esters such as methacrylate, acrylate, itaconate, fumarate, maleate, and crotonate. These two methods can be used alone or simultaneously.

[0150] The insulating substrates 110 and 510 respectively provided on the first substrate 100 and the second substrate 500 are colorless and transparent substrates having insulating properties. Examples of the insulating substrates 110 and 510 include substrates such as glass substrates and plastic substrates. Examples of the material of the glass substrate include glass such as float glass and soda-lime glass. Examples of the material of the plastic substrate include plastics such as polyethylene terephthalate, polybutylene terephthalate, polyether sulfone, polycarbonate, and alicyclic polyolefin.

[0151] The reflective layer 520 has the function of reflecting light incident from the observation surface side to the observation surface side. The reflective layer 520 has a fine concave-convex surface structure (MRS: MicroReflective Structure). The MRS shape is obtained by, for example, forming a concave-convex shape on an organic insulating film using a photolithography method and forming a film of various highly reflective metals such as Al and Ag alloys. The MRS shape can scatter external light within a certain angle range. Therefore, it is possible to efficiently use ambient light to obtain a bright reflective display.

[0152] The color filter layer 1CF is composed of a red color filter, a green color filter, and a blue color filter, and three picture elements, a picture element with a red color filter, a picture element with a green color filter, and a picture element with a blue color filter, are arranged in stripes in each pixel 1PX. In addition, a black matrix is ​​arranged in a grid shape to divide the color filters of each color.

[0153] In this embodiment, the second substrate 500 includes a color filter layer 1CF. By adopting such a method, light can be effectively transmitted from the first substrate 100 side to the liquid crystal layer 300 side, so that light can be irradiated from the first substrate 100 side, so that the polymer having the first photofunctional group and the second photofunctional group and the additive contained in the liquid crystal layer 300 can effectively react to form the first alignment layer 200 as a weakly anchored alignment layer.

[0154] The planarization film 530 has a function of planarizing unevenness generated by wiring, TFT, etc. arranged on the lower layer side. The planarization film 530 is mainly composed of an organic insulating material.

[0155] The common electrode 540 is an electrode formed into a substantially flat surface regardless of the boundary of the pixel 1PX. A common signal maintained at a fixed value is supplied to the common electrode 540, and the common electrode 540 is maintained at a fixed potential. The pixel electrode 560 is an electrode provided on the common electrode 540 via an insulating film 550 and arranged in each area surrounded by two adjacent gate lines 501 and two adjacent source lines 502, and is set to a potential corresponding to a data signal supplied via the corresponding TFT 503.

[0156] The common electrode 540 and the pixel electrode 560 can be formed, for example, as follows: a transparent conductive material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO) or an alloy thereof is formed in a single layer or multiple layers by sputtering or the like, and then patterned using a photolithography method.

[0157] The liquid crystal layer 300 includes a liquid crystal material. A voltage is applied to the liquid crystal layer 300, and the orientation state of the liquid crystal molecules 310 in the liquid crystal material is changed according to the applied voltage, thereby controlling the amount of light transmitted. The dielectric constant anisotropy (Δε) of the liquid crystal molecules 310 defined by the following formula L can have a positive value or a negative value. Liquid crystal molecules with positive dielectric anisotropy are also called positive liquid crystals, and liquid crystal molecules with negative dielectric anisotropy are also called negative liquid crystals. In addition, the long axis direction of the liquid crystal molecules becomes the direction of the slow axis. In addition, the liquid crystal molecules are uniformly oriented in a state where no voltage is applied (no voltage state), and the direction of the long axis of the liquid crystal molecules in the no voltage state is also called the direction of the initial orientation of the liquid crystal molecules.

[0158] Δε=(dielectric constant of the long axis direction of the liquid crystal molecule)-(dielectric constant of the short axis direction of the liquid crystal molecule) (Formula L)

[0159] The liquid crystal molecules 310 included in the liquid crystal layer 300 are horizontally aligned when no voltage is applied. The horizontal alignment of the liquid crystal molecules 310 means that when no voltage is applied to the liquid crystal layer 300 (when the voltage applied to the liquid crystal layer 300 is less than the threshold voltage), the liquid crystal molecules 310 in the liquid crystal layer 300 are aligned approximately parallel to the respective main surfaces of the first substrate 100 and the second substrate 500. In addition, in this specification, the voltage application state in which a voltage is applied between the common electrode and the pixel electrode is also referred to as the "voltage application state", and the no-voltage application state in which no voltage is applied between the common electrode and the pixel electrode is also referred to as the "no-voltage application state" or "no-voltage application state".

[0160] The phase difference of the liquid crystal layer 300 in the present embodiment in the region overlapping the reflective layer 520 is preferably 130 nm or more and 145 nm or less. By adopting such a mode, light leakage can be suppressed and a good black display can be realized.

[0161] Patent Documents 1 and 2 do not disclose a preferred range of the phase difference in the region of the liquid crystal layer 300 that overlaps the reflective layer 520 .

[0162] The linear polarizing plate 10 is an absorption type polarizing plate, and includes various linear polarizing plates such as a linear polarizing plate composed of a polyvinyl alcohol (PVA) dyed stretched film polarizer and a triacetyl cellulose (TAC) protective layer, a dye polarizing plate, and a coating type polarizing plate.

[0163] The λ / 2 plate 11 is a phase difference layer that imparts an in-plane phase difference of 245nm to 305nm to light of a wavelength of 550nm. Here, the phase difference layer is a layer having the following functions: using a birefringent material or the like to impart a phase difference to two orthogonal polarization components, thereby changing the state of the incident polarized light. In a liquid crystal display device in which the λ / 2 plate 11 is not provided, although only a good black reflectivity of 550nm (green) is obtained, light leakage sometimes occurs even when a black display is used for blue and red. As a result, there may be a situation where the black brightness cannot be fully suppressed and the contrast is reduced. On the other hand, if the λ / 2 plate 11 is provided as in the present embodiment, a good black color can be obtained without light leakage in the visual range of blue, green, and red. As a result, the contrast is improved. The λ / 2 plate 11 is, for example, arranged between the first substrate 100 and the linear polarizer 10.

[0164] When the thickness of the layer (film) is set to d (nm), the in-plane phase difference is calculated by Re = (nx-ny) × d. "nx" is the refractive index in the direction with the largest in-plane refractive index (i.e., the slow axis direction), "ny" is the refractive index in the direction orthogonal to the slow axis in the plane, and "nz" is the refractive index in the thickness direction. Unless otherwise specified, the refractive index refers to the value for light with a wavelength of 550nm.

[0165] The λ / 2 plate 11 can be made, for example, by stretching a high molecular polymer film. Specific examples of materials constituting the above-mentioned high molecular polymer film include, for example, chain polyolefins such as polycarbonate and polypropylene, polyesters such as polyethylene terephthalate and polyethylene naphthalate, cyclic polyolefins such as polynorbornene, polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polyarylate, polysulfone, polyether sulfone, polyphenylene sulfide, polyphenylene ether, polyaryl sulfone, polyvinyl alcohol, polyamide, polyimide, polyvinyl chloride, cellulose, etc. These can be used alone or in combination. More specifically, the λ / 2 plate 11 can be formed by stretching a polycarbonate film, as described in paragraph 0123 of Japanese Patent Application Publication No. 2004-325468.

[0166] The angle formed by the transmission axis azimuth of the linear polarizing plate 10 and the slow axis azimuth of the λ / 2 plate 11 is preferably 5° or more and 25° or less, and more preferably 10° or more and 20° or less.

[0167] The angle formed by the transmission axis azimuth of the linear polarizing plate 10 and the orientation azimuth of the first orientation layer 200 is preferably 65° or more and 85° or less, more preferably 70° or more and 80° or less. The angle formed by the transmission axis azimuth of the linear polarizing plate 10 and the orientation azimuth of the second orientation layer 400 is preferably 65° or more and 85° or less, more preferably 70° or more and 80° or less.

[0168] The angle formed by the slow axis orientation of the λ / 2 plate 11 and the orientation orientation of the first orientation layer 200 is preferably 50° to 70°, more preferably 55° to 65°. The angle formed by the slow axis orientation of the λ / 2 plate 11 and the orientation orientation of the second orientation layer 400 is preferably 50° to 70°, more preferably 55° to 65°.

[0169] The orientation direction of the first orientation layer 200 is parallel to the orientation direction of the second orientation layer 400. The orientation direction of the first orientation layer 200 is parallel to the orientation direction of the second orientation layer 400, which means that the angle (absolute value) formed by the two is greater than 0° and less than 3°, preferably greater than 0° and less than 1°, more preferably greater than 0° and less than 0.5°, and particularly preferably 0° (completely parallel).

[0170] The orientation of the first orientation layer 200 and the second orientation layer 400 can be measured by infrared spectroscopy, polarization analysis, SHG (second-harmonic generation) method, X-ray diffraction method, etc. In addition, the orientation in this specification is confirmed by polarization analysis.

[0171] (Implementation Method 2)

[0172] In this embodiment, the features unique to this embodiment are mainly described, and descriptions of contents overlapped with those of Embodiment 1 are omitted. This embodiment is substantially the same as Embodiment 1 except that the anchor energies of the first alignment layer 200 and the second alignment layer 400 are different. Figure 4 It is a schematic plan view of a liquid crystal display device according to Embodiment 2. Figure 5 is along Figure 4 In the above-mentioned embodiment 1, the first alignment layer 200 is a weakly anchored alignment layer, and the second alignment layer 400 is a strongly anchored alignment layer. Figure 4 and Figure 5 As shown, the second alignment layer 400 of the liquid crystal display device 1 of this embodiment is a weakly anchored alignment layer, and the first alignment layer 200 is a strongly anchored alignment layer. By adopting such a method, on the second substrate 500 side provided with the common electrode 540 and the pixel electrode 560, the liquid crystal molecules 310 are easily moved in a wider range not only near the electrodes, and the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be increased in the plane, and a high reflectivity can be achieved.

[0173] Here, comparing the above-mentioned embodiment 1 in which the first alignment layer 200 is a weakly anchored alignment layer and the present embodiment in which the second alignment layer 400 is a weakly anchored alignment layer, in the present embodiment, the liquid crystal molecules 310 are more likely to move on the second substrate 500 side provided with the common electrode 540 and the pixel electrode 560, while in the above-mentioned embodiment 1, the region in which the liquid crystal molecules 310 are more likely to move is expanded toward the first substrate 100 side. Therefore, compared with the present embodiment, the above-mentioned embodiment 1 can move the liquid crystal molecules 310 in a wider range, and can further improve the reflectivity. In addition, compared with the present embodiment, the above-mentioned embodiment 1 can set the optimal cell thickness for providing the maximum reflectivity to be thinner, which is also advantageous in terms of response speed.

[0174] On the other hand, in the present embodiment where the second alignment layer 400 is a weak anchor alignment layer, the anchoring force on the second substrate 500 side provided with the common electrode 540 and the pixel electrode 560 is weakened, so that the liquid crystal molecules 310 can be moved at a lower voltage. As a result, in the present embodiment, the reflectivity can be improved at a lower voltage compared to the above-mentioned embodiment 1.

[0175] The liquid crystal display device 1 of this embodiment is similar to the above-mentioned embodiment 1, and the second substrate 500 has a color filter layer 1CF. By adopting such a method, light can be effectively transmitted from the first substrate 100 side to the liquid crystal layer 300 side, so that light can be irradiated from the first substrate 100 side, and the polymer having the above-mentioned first photofunctional group and the above-mentioned second photofunctional group can react effectively with the additive contained in the liquid crystal layer 300 to form the second alignment layer 400 as a weakly anchored alignment layer.

[0176] The second alignment layer 400 of this embodiment preferably has an azimuthal anchoring energy of less than 1×10 -5 J / m 2 By adopting such a method, the liquid crystal molecules 310 on the second substrate 500 side can move more easily, and the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be further increased in the plane, thereby achieving high reflectivity.

[0177] The lower limit of the orientation angle anchoring energy of the second orientation layer 400 is not particularly limited, for example, 1×10 -8 J / m 2 above.

[0178] In addition, the first alignment layer 200 of the present embodiment is a strongly anchored alignment layer. The lower limit of the alignment angle anchoring energy of the first alignment layer 200 may be 1×10 -3 J / m 2 The upper limit of the orientation angle anchoring energy of the first orientation layer 200 is not particularly limited, and is, for example, 1 J / m 2 the following.

[0179] The phase difference of the liquid crystal layer 300 in the present embodiment in the region overlapping the reflective layer 520 is preferably 130 nm or more and 145 nm or less. By adopting such a mode, light leakage can be suppressed and a good black display can be realized.

[0180] (Implementation 3)

[0181] In this embodiment, the features unique to this embodiment are mainly described, and descriptions of contents overlapped with those of Embodiments 1 and 2 are omitted. This embodiment is substantially the same as Embodiment 1 except that the anchor energies of the first alignment layer 200 and the second alignment layer 400 are different. Figure 6 It is a schematic plan view of a liquid crystal display device according to Embodiment 3. Figure 7 is along Figure 6 In the above-mentioned embodiments 1 and 2, one of the first alignment layer 200 and the second alignment layer 400 is a weakly anchored alignment layer, and the other is a strongly anchored alignment layer. Figure 6 and Figure 7 As shown, the first alignment layer 200 and the second alignment layer 400 of the liquid crystal display device 1 of this embodiment are both weakly anchored alignment layers. By adopting such a method, the liquid crystal molecules 310 become easy to move on both sides of the first substrate 100 side and the second substrate 500 side, and the liquid crystal molecules 310 can be moved in a wider range, which can further improve the reflectivity.

[0182] The first alignment layer 200 of this embodiment preferably has an azimuthal anchoring energy of less than 1×10 -5 J / m 2 By adopting such a method, the liquid crystal molecules 310 on the first substrate 100 side become easier to move, and the liquid crystal molecules 310 can be moved in a wider area. As a result, the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be further increased, and the reflectivity can be further improved. In addition, the optimal cell thickness for providing the maximum reflectivity can be set to be thinner.

[0183] The lower limit of the orientation angle anchoring energy of the first orientation layer 200 is not particularly limited, and is, for example, 1×10 -10 J / m 2 above.

[0184] The second alignment layer 400 of this embodiment preferably has an azimuthal anchoring energy of less than 1×10 -5 J / m 2By adopting this method, the liquid crystal molecules 310 on the second substrate 500 side can move more easily, and the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be further increased in the plane, so that high reflectivity can be achieved. In addition, the optimal cell thickness range that gives the maximum reflectivity can be set to be thinner.

[0185] The lower limit of the orientation angle anchoring energy of the second orientation layer 400 is not particularly limited, for example, 1×10 -10 J / m 2 above.

[0186] As shown in Embodiments 1 to 3, by making at least one of the first orientation layer 200 and the second orientation layer 400 a weakly anchored orientation layer, the anchoring force that constrains the liquid crystal molecules 310 on the side of the weakly anchored orientation layer is weakened, and the liquid crystal molecules 310 become easy to move. As a result, the liquid crystal molecules 310 are rotated in a wider area than the liquid crystal display device 1R of the above-mentioned comparative method, and the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be made larger in the plane more uniformly, and a high reflectivity can be achieved. That is, by setting the orientation of the substrate on at least one side of the liquid crystal panel to weak anchoring (zero plane anchoring, smooth interface), the liquid crystal molecules 310 near the substrate that were previously difficult to move can also be moved, and the obtained modulation width of nd can be made larger in the plane more uniformly. As a result, in the transverse electric field mode, a high reflectivity comparable to that in the longitudinal electric field mode can be obtained. At the same time, since the liquid crystal molecules 310 in a wide range can be moved at a lower voltage, low voltage (low power consumption) can be achieved.

[0187] As described above, in Embodiments 1 to 3, the modulation width of Δnd of the liquid crystal layer 300 is increased, and the light reaching the reflective layer 520 is made close to linearly polarized light, thereby improving the reflectivity.

[0188] The liquid crystal display device disclosed in the above-mentioned patent document 1 is a bistable nematic liquid crystal display device, and no research has been conducted on the liquid crystal display device in the transverse electric field mode. The liquid crystal display device of patent document 1 is a liquid crystal display device that switches the torsion angle of the liquid crystal molecules to a binary value of 0 degrees and 180 degrees by a voltage pulse, and can only display white and black binary values. Since the liquid crystal molecules are vertically oriented once when the data is rewritten, they are switched to another stable state (twist angle 0 degrees or 180 degrees), so the response speed is slow. In addition, in the liquid crystal display device disclosed in the above-mentioned patent document 1, there is a possibility that a pixel with a torsion angle of 0 degrees is adjacent to a pixel with a torsion angle of 180 degrees, and an orientation defect is generated at the boundary between 0° torsion and 180° torsion. When the fineness is not high, the orientation defect portion (non-displayable area) is smaller than the displayable area, so the orientation defect can be shielded by the black matrix portion, but in the case of high fineness, the area occupied by the orientation defect becomes larger. Therefore, in the liquid crystal display device disclosed in patent document 1, high fineness is not possible. On the other hand, since the liquid crystal display device 1 of Embodiments 1 to 3 is an FFS mode liquid crystal display device, the response speed is fast and high definition is also possible.

[0189] The anchoring energy disclosed in Patent Document 1 is an anchoring energy for stabilizing the bistability, and therefore the polar angle anchoring energy of the weakly anchored alignment film is 6×10 -5 ~2×10 -4 J / m 2 , the azimuthal anchoring energy is 1×10 -5 ~5×10 -5 J / m 2 , the polar angle anchoring energy and azimuthal angle anchoring energy of the oriented film are set to a very narrow range.

[0190] On the other hand, in the implementation mode There is no restriction on the polar angle anchoring energy, and the azimuthal angle anchoring energy only needs to be set within the above range, so the range of material selection and manufacturing process selection of the alignment layer is wide.

[0191] In the above-mentioned Patent Document 2, a technology is disclosed in which a liquid crystal layer containing polymerizable monomers is polymerized by applying a voltage to the monomers, and the tilt of the liquid crystal molecules is memorized in the polymer (hereinafter also referred to as a pretilt angle imparting technology using a polymer). In the embodiment of Patent Document 2, the anchoring energy is increased by applying the pretilt angle imparting technology using a polymer to an orientation film with a small anchoring energy, thereby obtaining a strongly anchored orientation film with a strong orientation limiting force. When such an orientation film of Patent Document 2 is applied to a reflective liquid crystal display device or a semi-transmissive liquid crystal display device in a lateral electric field mode, the orientation of the liquid crystal molecules when a voltage is applied also has a distribution in the thickness direction and the in-plane direction, so the reflectivity becomes low. In Patent Document 2, any orientation film has a strong anchoring force, but in the embodiment, In the structure of Patent Document 2, at least one of the first alignment layer 200 and the second alignment layer 400 is a weakly anchored alignment layer, which is different from the structure of Patent Document 2.

[0192] The above-mentioned Patent Document 3 discloses that if the anchoring strength in one of the first liquid crystal orientation region and the second liquid crystal orientation region is reduced to below the allowable value, poor display such as afterimage phenomenon will occur, so it is necessary to pay attention to the difference in anchoring strength in the two regions. That is, Patent Document 3 intends to use a strongly anchored orientation film. When this technology is applied to a reflective liquid crystal display device or a semi-transmissive liquid crystal display device in a lateral electric field mode, the orientation of the liquid crystal molecules when a voltage is applied also has a distribution in the thickness direction and the in-plane direction, so the reflectivity becomes low. On the other hand, in the embodiment In the configuration described above, at least one of the first alignment layer 200 and the second alignment layer 400 is a weakly anchored alignment layer, which is different from the configuration described in Patent Document 3.

[0193] <Modification 1>

[0194] In the above-mentioned embodiments 1 to 3, a reflective liquid crystal display device is described. However, regarding a semi-transmissive liquid crystal display device in which the pixel 1PX has a reflective area provided with a reflective layer 520 and a transmissive area not provided with the reflective layer 520, by using at least one of the first orientation layer 200 and the second orientation layer 400 as a weakly anchored orientation layer, the modulation width of the phase difference Δnd of the liquid crystal layer 300 can be increased, thereby achieving high reflectivity.

[0195] Figure 8 It is a schematic plan view of a liquid crystal display device according to Modification 1. Fig. 9 is along Figure 8 Schematic diagram of the cross section of the B1-B2 line in FIG. Figure 8 as well as Fig. 9 As shown, the liquid crystal display device 1 of this variation is substantially the same as the first to third embodiments, except that the opening 520H is provided in a predetermined ratio in the reflective layer 520 and the λ / 2 plate 11 is not provided. The reflective layer 520 is provided in a part of the pixel 1PX. The liquid crystal display device 1 of this variation is a semi-transmissive liquid crystal display device having a reflective region R provided with the reflective layer 520 and a transmissive region T not provided with the reflective layer 520. In the transmissive region T, light emitted from the backlight 30 is emitted to the observation side through the liquid crystal layer 300, thereby displaying.

[0196] In the liquid crystal display device 1 of this modification, a gap forming layer is provided at a position corresponding to that between the planarizing film 530 and the common electrode 540 in the above-described first embodiment, and a step control layer 531 composed of the planarizing film 530 and the gap forming layer is provided, whereby the thickness of the liquid crystal layer 300 in the reflective region R is set to be approximately half the thickness of the liquid crystal layer 300 in the transmissive region T. Alternatively, the gap forming layer may be provided between the insulating substrate 110 and the first alignment layer 200 instead of between the planarizing film 530 and the common electrode 540, whereby the thickness of the liquid crystal layer 300 in the reflective region R is set to be approximately half the thickness of the liquid crystal layer 300 in the transmissive region T.

[0197] As a specific example of this variation, variations 1-1 and 1-2 are cited to illustrate the following. The liquid crystal display device of variation 1-1 is a variation in variation 1 corresponding to the above-mentioned embodiment 1. In the liquid crystal display device 1 of variation 1-1, the first alignment layer 200 on the opposing substrate side is a weakly anchored alignment layer, and the second alignment layer 400 on the TFT substrate side is a strongly anchored alignment layer. In addition, the liquid crystal display device of this variation 1-2 is a variation in variation 1 corresponding to the above-mentioned embodiment 2. In the liquid crystal display device 1 of variation 1-2, the first alignment layer 200 on the opposing substrate side is a strongly anchored alignment layer, and the second alignment layer 400 on the TFT substrate side is a weakly anchored alignment layer.

[0198] Fig.10 1 is a diagram showing the transmittance of the liquid crystal layer in the transmission region of the modified examples 1-1 and 1-2 and the conventional FFS mode transmissive liquid crystal display device. The conventional FFS mode transmissive liquid crystal display device does not include the reflective layer 520, and the first alignment layer and the second alignment layer are both strongly anchored alignment layers. In addition, the liquid crystal display device has the same structure as the liquid crystal display devices of the modified examples 1-1 and 1-2. In any of the modified examples 1-1 and 1-2 and the conventional FFS mode liquid crystal display device, the alignment direction of the first alignment layer is parallel to the alignment direction of the second alignment layer.

[0199] In conventional FFS mode transmissive liquid crystal display devices, the phase difference Δnd of the liquid crystal layer is usually set to If Δnd is too high, the displayed color tone will be yellowish, so it is mainly set to However, when the first alignment layer 200 is set as a weakly anchored alignment layer (the opposite substrate side is set as a weakly anchored alignment layer) as in Modification Example 1-1, Fig.10As shown in FIG. 1 , by setting the phase difference Δnd of the liquid crystal layer 300 in the transmission region T to be greater than 220 nm and less than 320 nm, the chromaticity of white is not colored yellow, and the transmittance can be improved. In addition, since the cell thickness can be reduced, the response speed can also be improved. In the modification 1-1, from the viewpoint of improving the transmittance, the phase difference Δnd of the liquid crystal layer 300 in the transmission region T is preferably greater than 250 nm and less than 310 nm.

[0200] In a semi-transmissive liquid crystal display device, the thickness of the liquid crystal layer 300 in the reflective region R is usually set to about half the thickness of the liquid crystal layer 300 in the transmissive region T. However, in this modification, from the viewpoint of improving transmittance, the phase difference of the liquid crystal layer 300 in the transmissive region T is preferably set to 220 nm or more and 320 nm or less. In addition, as described in the above-mentioned embodiment 1, from the viewpoint of achieving a good white reflectivity, the phase difference of the liquid crystal layer 300 in the reflective region R is preferably set to 80 nm or more and 180 nm or less. In this way, in this modification 1-1, the phase difference of the liquid crystal layer 300 in the reflective region R and the transmissive region T can be set from a different viewpoint from that of the conventional semi-transmissive liquid crystal display device. In the conventional semi-transmissive FFS display device, it is preferable to set the phase difference of the liquid crystal layer in the transmissive region to 330 nm and the phase difference of the liquid crystal layer in the reflective region to 137.5 nm. Therefore, it is necessary to set a difference in the thickness of the liquid crystal layer between the transmissive region and the reflective region, which is equivalent to the difference of 192.5 nm between the two. On the other hand, in this variation 1-1, for example, the phase difference of the liquid crystal layer in the transmission region is preferably set to 280nm, and the phase difference of the liquid crystal layer in the reflection region is preferably set to 137.5nm, so that the difference is 142.5nm. Since the difference is smaller than that of the existing display device, the step for gap control can also be reduced, resulting in a thinner panel and a simpler manufacturing process.

[0201] In addition, if Fig.10 As shown, the liquid crystal display device 1 of modification 1-2 in which the second alignment layer 400 is a weakly anchored alignment layer (the TFT substrate side is weakly anchored) can also improve the transmittance of the phase difference Δnd of the liquid crystal layer 300 compared with the conventional FFS mode transmissive liquid crystal display device. In modification 1-2, as Fig.10 As shown, by setting the phase difference Δnd of the liquid crystal layer 300 in the transmission region T to be greater than 330nm and less than 350nm, the chromaticity of white is not colored yellow, and the transmittance can be improved. In addition, from the viewpoint of improving the response speed, it is preferred that the phase difference Δnd of the liquid crystal layer 300 in the transmission region T is set to be greater than 300nm and less than 330nm.

[0202] In addition, regarding the range of the phase difference Δnd of the above-mentioned liquid crystal layer 300, the case where the orientation direction of the first orientation layer 200 is parallel to the orientation direction of the second orientation layer 400 is shown. When the orientation direction of the first orientation layer 200 is not parallel to the orientation direction of the second orientation layer 400, the range of the phase difference Δnd of the liquid crystal layer 300 is not limited to the above-mentioned range, but by setting the first orientation layer 200 as a weakly anchored orientation layer, the same effect of thinning the unit thickness can be obtained.

[0203] In addition, the liquid crystal display device 1 of this modification does not include the λ / 2 plate 11 , but may include the λ / 2 plate 11 as in the first to third embodiments.

[0204] The linear polarizer 20 is an absorption type polarizer, and may be any of various linear polarizers such as a linear polarizer composed of a polyvinyl alcohol (PVA) dyed stretched film polarizer and a triacetyl cellulose (TAC) protective layer, a dye polarizer, or a coating type polarizer.

[0205] The angle formed by the transmission axis azimuth of the linear polarizing plate 10 and the transmission axis azimuth of the linear polarizing plate 20 is preferably 87° or more and 93° or less, more preferably 89° or more and 91° or less, and further preferably 90°.

[0206] The angle formed by the transmission axis orientation of the linear polarizing plate 10 and the orientation orientation of the first orientation layer 200 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably 45°. The angle formed by the transmission axis orientation of the linear polarizing plate 10 and the orientation orientation of the second orientation layer 400 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably 45°.

[0207] <Modification 2>

[0208] In the above-mentioned embodiments 1 to 3 and modification 1, the case where the orientation azimuth of the first orientation layer 200 is parallel to the orientation azimuth of the second orientation layer 400 is described, but the orientation azimuth of the first orientation layer 200 may not be parallel to the orientation azimuth of the second orientation layer 400. In this case, the phase difference of the liquid crystal layer 300 in the region overlapping the reflective layer 520 is preferably greater than or equal to 240 nm and less than or equal to 260 nm. By adopting such a method, a good black display can be achieved.

[0209] In this modification, the angle formed by the alignment azimuth of the first alignment layer 200 and the alignment azimuth of the second alignment layer 400 is preferably greater than or equal to 60° and less than or equal to 80°, and more preferably greater than or equal to 65° and less than or equal to 75°.

[0210] The angle formed by the transmission axis azimuth of the linear polarizing plate 10 and the orientation azimuth of the first orientation layer 200 is preferably 125° or more and 145° or less, more preferably 130° or more and 140° or less. The angle formed by the transmission axis azimuth of the linear polarizing plate 10 and the orientation azimuth of the second orientation layer 400 is preferably 55° or more and 75° or less, more preferably 60° or more and 70° or less.

[0211] The angle formed by the slow axis orientation of the λ / 2 plate 11 and the orientation orientation of the first orientation layer 200 is preferably 110° to 130°, more preferably 115° to 125°. The angle formed by the slow axis orientation of the λ / 2 plate 11 and the orientation orientation of the second orientation layer 400 is preferably 40° to 60°, more preferably 45° to 55°.

[0212] <Variation 3>

[0213] In the above-mentioned embodiment In the modification example 2, the λ / 2 plate 11 is provided. However, the λ / 4 plate 12 may be provided instead of the λ / 2 plate 11. In the modification example 1, the λ / 4 plate 12 may be provided. By providing the λ / 4 plate 12, for example Fig.12 By setting the slow axis orientation as shown, a good black display can be obtained regardless of the phase difference of the liquid crystal layer 300. The λ / 4 plate 12 can be arranged at any position as long as it is closer to the observation surface than the reflective layer 520 and closer to the back surface than the linear polarizer 10.

[0214] Fig.11 is a cross-sectional schematic diagram of a liquid crystal display device according to a third variation, showing the embodiment The case where a λ / 4 plate is configured instead of a λ / 2 plate. Fig.12 1 is a diagram showing an example of the transmission axis orientation of the polarizing plate, the orientation orientations of the first and second orientation layers, and the slow axis orientation of the λ / 4 plate of the liquid crystal display device of Modification Example 3. Fig.11 and Fig.12 As shown, the liquid crystal display device 1 of this modified example does not have a λ / 2 plate 11 between the linear polarizer 10 and the first substrate 100, and has a λ / 4 plate 12 between the second alignment layer 400 and the second substrate 500, for example Fig.12 As shown, the alignment directions of the first alignment layer 200 and the second alignment layer 400 are set.

[0215] The λ / 4 plate 12 is a phase difference layer that provides an in-plane phase difference of 107.5 nm to 167.5 nm to light having a wavelength of 550 nm.

[0216] Examples of the material of the λ / 4 plate 12 include photopolymerizable liquid crystal materials, etc. Examples of the structure of the photopolymerizable liquid crystal material include a structure having a photopolymerizable group such as an acrylate group or a methacrylate group at the end of the liquid crystal molecule skeleton.

[0217] The λ / 4 plate 12 can be formed, for example, by the following method. First, a photopolymerizable liquid crystal material is dissolved in an organic solvent such as propylene glycol monomethyl ether acetate (PGMEA). Next, the obtained solution is applied to the surface of a substrate (e.g., a polyethylene terephthalate (PET) film) to form a coating of the solution. Then, the coating of the solution is sequentially pre-fired, irradiated with light (e.g., ultraviolet irradiation), and formally fired to form a λ / 4 plate.

[0218] For example, a stretched polymer film may be used as the λ / 4 plate 12. Examples of the material of the polymer film include cycloolefin polymer, polycarbonate, polysulfone, polyethersulfone, polyethylene terephthalate, polyethylene, polyvinyl alcohol, norbornene, triacetyl cellulose, and diacyl cellulose.

[0219] The angle between the transmission axis azimuth of the linear polarizing plate 10 and the slow axis azimuth of the λ / 4 plate 12 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably Fig.12 45° shown.

[0220] The angle between the transmission axis orientation of the linear polarizing plate 10 and the orientation orientation of the first orientation layer 200 is preferably 0° to 10°, more preferably 0° to 5°, and particularly preferably Fig.12 The angle between the transmission axis orientation of the linear polarizer 10 and the orientation orientation of the second orientation layer 400 is preferably 0° or more and 10° or less, more preferably 0° or more and 5° or less, and particularly preferably Fig.12 0° shown.

[0221] The angle between the slow axis orientation of the λ / 4 plate 12 and the orientation orientation of the first orientation layer 200 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably Fig.12 The angle between the slow axis orientation of the λ / 4 plate 12 and the orientation orientation of the second orientation layer 400 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably Fig.12 45° shown.

[0222] As specific examples of this variation, variations 3-1 and 3-2 are cited to illustrate the following. Variation 3-1 is a variation corresponding to the above-mentioned embodiment 1 in variation 3. In the variation 3-1 liquid crystal display device 1, the first alignment layer 200 on the opposing substrate side is a weakly anchored alignment layer, and the second alignment layer 400 on the TFT substrate side is a strongly anchored alignment layer. In addition, the liquid crystal display device of variation 3-2 is a variation corresponding to the above-mentioned embodiment 2 in variation 3. In the liquid crystal display device 1 of variation 3-2, the first alignment layer 200 on the opposing substrate side is a strongly anchored alignment layer, and the second alignment layer 400 on the TFT substrate side is a weakly anchored alignment layer.

[0223] Fig.13 3-1 and the conventional FFS mode reflective liquid crystal display device, and the reflectivity of the liquid crystal layer is plotted against the phase difference. In order to obtain a good white reflectivity, in the conventional FFS mode reflective liquid crystal display device in which the first alignment layer 200 is a strong anchor alignment layer, when the alignment direction of the first alignment layer 200 is parallel to the alignment direction of the second alignment layer 400, as shown in FIG. Fig.13 As shown, the phase difference of the liquid crystal layer 300 in the region overlapping with the reflective layer 520 is preferably 130 nm or more and 230 nm or less. On the other hand, in the liquid crystal display device 1 of this modification 3-1 in which the first alignment layer 200 is a weak anchor alignment layer, when the alignment azimuth of the first alignment layer 200 is parallel to the alignment azimuth of the second alignment layer 400, as shown in FIG. Fig.13 As shown, the phase difference in the region where the liquid crystal layer 300 overlaps with the reflective layer 520 is preferably 80 nm or more and 180 nm or less. By adopting such a method, a good white reflectivity (high white reflectivity) can be achieved. From the viewpoint of achieving a good white reflectivity, the phase difference in the region where the liquid crystal layer 300 overlaps with the reflective layer 520 is more preferably 150 nm or more and 180 nm or less.

[0224] Here, the phase difference Δnd of the liquid crystal layer is the product of the refractive index anisotropy Δn of the liquid crystal material and the thickness d of the liquid crystal layer. Therefore, reducing Δnd is equivalent to reducing the thickness d of the liquid crystal layer. The response speed of the liquid crystal is proportional to the square of the cell thickness. Therefore, being able to reduce the cell thickness is very advantageous in terms of response speed. In this modified example, by providing the λ / 4 plate 12 as described above and, for example, Fig.12 By setting the slow axis orientation in this way, a good black display can be obtained that is not dependent on the phase difference of the liquid crystal layer 300. Therefore, in Modification 3-1, a liquid crystal display device having excellent black brightness (contrast), maximum white reflectivity, and response speed can be obtained.

[0225] In addition, the preferred range of the phase difference of the liquid crystal layer 300 for obtaining a good white reflectivity is described above, and this range is a preferred range when the orientation direction of the first orientation layer 200 is parallel to the orientation direction of the second orientation layer 400. Therefore, in the case where the orientation direction of the first orientation layer 200 is not parallel to the orientation direction of the second orientation layer 400, in the case where various phase difference plates other than this modification are configured, etc., the preferred range of the phase difference of the liquid crystal layer 300 for obtaining a suitable white reflectivity is not limited to the above range. However, in either method, by using the first orientation layer 200 as a weakly anchored orientation layer, the effect of being able to reduce the cell thickness is obtained.

[0226] In addition, in the liquid crystal display device 1 of this modification 3-2 in which the second alignment layer 400 is a weak anchor alignment layer, when the alignment azimuth of the first alignment layer 200 is parallel to the alignment azimuth of the second alignment layer 400, the phase difference of the liquid crystal layer 300 in the region overlapping with the reflective layer 520 is preferably 130 nm or more and 230 nm or less. By adopting such a method, a good white reflectivity can be achieved. From the viewpoint of achieving a good white reflectivity, the phase difference of the liquid crystal layer 300 in the region overlapping with the reflective layer 520 is more preferably 200 nm or more and 230 nm or less.

[0227] <Variation 4>

[0228] Fig.14 It is a schematic cross-sectional view of a liquid crystal display device according to variation 4. Fig.15 1 is a diagram showing an example of the transmission axis orientation of the polarizing plate, the orientation orientation of the first orientation layer, and the orientation orientation of the second orientation layer of the liquid crystal display device of Modification 4. In the above-mentioned Embodiments 1 to 3 and Modification 2, the λ / 2 plate 11 is provided between the linear polarizing plate 10 and the first substrate 100. Fig.14 As shown, the λ / 2 plate 11 may not be provided. In this case, the angle between the transmission axis orientation of the linear polarizer 10 and the orientation orientation of the first orientation layer 200 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably Fig.15 The angle between the transmission axis orientation of the linear polarizer 10 and the orientation orientation of the second orientation layer 400 is preferably 35° or more and 55° or less, more preferably 40° or more and 50° or less, and particularly preferably Fig.15 45° shown.

[0229] <Variation 5>

[0230] The above-mentioned embodiment And Modifications In the embodiment, the second substrate 500 has a color filter layer 1CF, but the color filter layer 1CF may also have a first substrate 100. In this way, when the color filter layer 1CF and the reflective layer 520 are provided on different substrates, even if additional irradiation is performed from either the first substrate 100 or the second substrate 500, the light will be absorbed or reflected by the color filter layer 1CF or the reflective layer 520, so that the photo-alignment polymer contained in the alignment layer cannot react with the additive contained in the liquid crystal layer 300, and a weakly anchored alignment layer cannot be formed by additional irradiation. In this modification, a weakly anchored alignment layer can be formed by rubbing a film containing a rubbed alignment layer polymer or forming an alignment film material containing an alignment film polymer without performing an alignment treatment. Fig.16 FIG. 1 is an example of a cross-sectional schematic diagram of a liquid crystal display device according to Modification 5, showing a case where the color filter layer is arranged on the first substrate side in Embodiment 1. Fig.16 As shown, the first substrate 100 included in the liquid crystal display device 1 of this modification may include an insulating substrate 110 and a color filter layer 1CF, and the second substrate 500 may include a reflective layer 520 .

[0231] <Variation 6>

[0232] In the above-mentioned embodiments 1 to 3 and modified examples 1 to 5, the pixel electrode 560 provided with slits is arranged on the planar common electrode 540 via the insulating film 550, but the arrangement of the common electrode 540 and the pixel electrode 560 may be reversed. In this case, the common electrode 540 provided with slits is arranged on the planar pixel electrode 560 formed so as to occupy each pixel region via the insulating film 550.

[0233] <Variation 7>

[0234] The liquid crystal display device of the above-mentioned embodiments 1 to 3 and modified examples 1 to 6 is an FFS mode liquid crystal display device in which a pixel electrode 560 with a slit is arranged on a planar common electrode 540 via an insulating film 550, but it can also be an IPS (In Plane Switching) mode liquid crystal display device in which the common electrode 540 and the pixel electrode 560 are comb-tooth electrodes, and the common electrode 540 as a comb-tooth electrode and the pixel electrode 560 as a comb-tooth electrode are arranged on the same electrode layer in a manner in which the comb teeth are interlocked with each other.

[0235] <Variation 8>

[0236] The above-mentioned embodiment And Variations In the embodiment, the first substrate 100, the first alignment layer 200, the liquid crystal layer 300, the second alignment layer 400 and the second substrate 500 are sequentially arranged from the observation side to the back side, but these components can also be arranged in the reverse order. In this way, by making at least one of the first alignment layer 200 and the second alignment layer 400 a weakly anchored alignment layer, the reflectivity can be improved. Fig.17 is an example of a cross-sectional schematic diagram of a liquid crystal display device of Modification Example 8, showing an embodiment configured in the reverse order The situation of components. Fig.17 As shown, the liquid crystal display device 1 of this modified example includes a linear polarizer 10, a λ / 2 plate 11, a second substrate 500, a second orientation layer 400, a liquid crystal layer 300, a first orientation layer 200 and a first substrate 100 in sequence from the observation side to the back side. The first substrate 100 may also include an insulating substrate 110 and a reflective layer 520 arranged on the liquid crystal layer 300 side of the insulating substrate 110.

[0237] <Variation 9>

[0238] In the above-mentioned embodiments 1 to 3 and variations 1 to 8, the slits provided in the pixel electrode 560 or the common electrode 540 are in a straight line shape, but the slits may also be in the shape of a Japanese Hiragana character "く" (a shape in which a straight line is bent at one point). By adopting such a method, when a voltage is applied, two liquid crystal domains in which liquid crystal molecules are oriented in different directions can be formed in one pixel, and a dual-domain structure is adopted, thereby improving the viewing angle.

[0239] <Variation 10>

[0240] In the above-mentioned first to third embodiments and modified examples 1 to 9, each pixel 1PX is not divided, but each pixel 1PX may be divided into a plurality of sub-pixels and half-tone display may be performed by area grayscale.

[0241] Compared with conventional lateral electric field mode liquid crystal display devices, lateral electric field mode liquid crystal display devices with weakly anchored alignment layers may have worse burn-in characteristics. Specifically, burn-in is visible when a half-tone is displayed after a burn-in test.

[0242] Fig.18 is a VR characteristic curve diagram showing a liquid crystal display device having a lateral electric field mode with a weak anchor alignment layer. Fig.18 As shown, a liquid crystal display device in a lateral electric field mode with a weakly anchored orientation layer has a steep VR characteristic curve. Therefore, when the VR characteristics deviate due to charge accumulation, orientation deformation, etc. when the liquid crystal display device is continuously driven, a brightness difference will occur even if the same grayscale voltage is applied, which will cause screen burn-in and be easily visible.

[0243] Fig.19 This is a schematic diagram for explaining the display of half-gray scales by the liquid crystal display device according to the tenth modification. Fig. 20 This is a diagram for explaining white display and black display in a curve diagram showing VR characteristics of a liquid crystal display device. Fig.19 As shown in FIG. 1 , each pixel 1PX is divided into a plurality of sub-pixels 2PX, and intermediate grayscale is displayed by area grayscale. In area grayscale driving, a sub-pixel only displays white and black, and the intermediate grayscale is displayed by the area ratio of black to white. That is, the intermediate grayscale (grayscale) is expressed only by white and black. Fig. 20 As shown in FIG. 1 , both white and black display are at saturation points in the curve diagram representing VR characteristics, so even if screen burn-in occurs, no brightness difference is generated, and screen burn-in is not easily observed. That is, in the area grayscale of this modified example, only a voltage that does not generate a brightness difference can be used, so screen burn-in is difficult to be visually recognized.

[0244] As a driving method for area grayscale, a binary display of 0 / 1 may be performed by MIP driving (Memory in Pixel), or a binary display of black and white in a normal hold driving may be used.

[0245] For example, when one pixel is divided into four sub-pixels, five grayscale displays can be performed: (black, black, black, black), (black, black, black, white), (black, black, white, white), (black, white, white, white), (white, white, white, white). When a color filter is used, R / G / B can each represent five grayscales, so 125 colors can be displayed.

[0246] When a color filter is used to divide a pixel into three sub-pixels using three-pixel division, R / G / B can each express four grayscales, so 4×4×4=64 colors can be displayed. In addition, even if it is a two-pixel division, if the area ratio is set to 1:2, etc., 64 colors can be displayed.

[0247] In the case of a semi-transmissive liquid crystal display device, only the transmissive portion may be displayed in area grayscale, only the reflective portion may be displayed in area grayscale, or both may be displayed in area grayscale.

[0248] Patent Document 4 discloses a technique for providing an inorganic phosphor in a MIP type reflective liquid crystal display device that displays color gradations by area gradation to expand the color gradation expression, and cites the FFS mode as an embodiment.

[0249] The reflectivity of a conventional FFS mode liquid crystal display device is low, and it is not practical when used in a reflective liquid crystal display device, but there is no detailed disclosure of the FFS mode in Patent Document 4. In addition, in a reflective liquid crystal display device, since the cell thickness is thin, the driving voltage is also relatively high, which limits the driver and IC (integrated circuit), but in this regard, Patent Document 4 does not disclose the details of the FFS mode. Furthermore, Patent Document 4 does not disclose the materials and design information of the alignment film, liquid crystal, etc. used in the FFS mode liquid crystal display device. In addition, the currently practical reflective liquid crystal display devices are almost all longitudinal electric field modes, and do not adopt transverse electric field modes such as the FFS mode.

[0250] In this variant, by using a weakly anchored alignment layer not disclosed in Patent Document 4, low voltage drive (low power consumption) and high reflectivity can be achieved in FFS mode, so it can be applied to a reflective liquid crystal display device. In addition, as described above, the VR characteristics of a liquid crystal display device in a lateral electric field mode with a weakly anchored alignment layer are steep. Therefore, in this variant, each pixel is divided into a plurality of sub-pixels, and by applying an area grayscale in which each sub-pixel is displayed in black and white binary values, only a voltage that does not produce a brightness difference is used, which can suppress screen burn-in. In this way, in this variant, low voltage drive, low power consumption, and screen burn-in suppression, which are not specifically implemented by means disclosed in Patent Document 4, can be achieved in a reflective liquid crystal display device in a lateral electric field mode.

[0251] Fig.21 Schematic diagram for explaining pixels of a liquid crystal display device according to Modification 10. Fig. 22 1 is a schematic diagram for explaining the grayscale of a pixel of a liquid crystal display device according to a modification example 10. In the liquid crystal display device 1 of this modification example, each pixel 1PX is divided into three sub-pixels. Specifically, Fig.21 and Fig. 22 As shown, the red pixel 1PXR is divided into a first sub-pixel 21PXR, a second sub-pixel 22PXR and a third sub-pixel 23PXR, the green pixel 1PXG is divided into a first sub-pixel 21PXG, a second sub-pixel 22PXG and a third sub-pixel 23PXG, and the blue pixel 1PXB is divided into a first sub-pixel 21PXB, a second sub-pixel 22PXB and a third sub-pixel 23PXB.

[0252] However, the first sub-pixels 21PXR, 21PXG, and 21PXB and the third sub-pixels 23PXR, 23PXG, and 23PXB are connected to each other, and are actually divided into two with an area ratio of 1:2. Fig. 22 As shown, 4 grayscales×4 grayscales×4 grayscales=64 colors can be displayed.

[0253] Fig.23 This is a circuit diagram simply showing an example of the circuit configuration of a pixel of a liquid crystal display device according to Modification 10. Fig.24 1 is a circuit diagram specifically showing an example of a circuit structure of a pixel of a liquid crystal display device according to Modification 10. The second substrate 500 provided in the liquid crystal display device 1 of this modification is, for example, a TFT substrate. Fig.23 As shown schematically, it includes gate lines 501, source lines 502, a storage circuit (storage circuit unit) 30M, and a display voltage supply circuit (display voltage supply circuit unit) 30D. The storage circuit 30M is, for example, a one-bit SRAM circuit, and is provided in each pixel. The specific structure and operation of the storage circuit 30M and the like will be described later.

[0254] The liquid crystal display device 1 of this variant is a reflective liquid crystal display device in which a storage circuit 30M is provided in each pixel. A liquid crystal display device in which a memory circuit is provided in each pixel is also referred to as a "memory liquid crystal display device" or a "MIP liquid crystal display device". The reflective liquid crystal display device of the MIP mode can realize a display based on an analog display mode and a display based on a memory display mode by having a memory (storage circuit 30M) for storing data in the pixel 1PX. Here, the analog display mode refers to a display mode for displaying the grayscale of a pixel in an analog manner. In addition, the memory display mode refers to a display mode for digitally displaying the grayscale of the pixel 1PX based on binary information (logical "1" / logical "0") stored in the memory in the pixel 1PX.

[0255] In the case of the memory display mode, since the information stored in the memory is used, it is not necessary to perform a write operation of a signal potential reflecting grayscale (a potential corresponding to a data signal) in a frame cycle. Therefore, in the case of the memory display mode, compared with the case of the analog display mode in which a write operation of a signal potential reflecting grayscale is required in a frame cycle, less power consumption is sufficient, that is, low power consumption of the liquid crystal display device can be achieved. That is, since the memory liquid crystal can reduce the refresh rate (also called the frame rate or the driving frequency), it has excellent low power consumption characteristics.

[0256] The liquid crystal display device 1 has a driving circuit that applies either a black voltage or a white voltage to the liquid crystal layer 300 at a frame rate of less than 1 fps. When the driving circuit applies a white voltage to the liquid crystal layer 300 across multiple frames, the potential of the common electrode 540 (also referred to as Vcom) is used as a reference to apply a white display voltage with reversed polarity to each frame. That is, the liquid crystal display device 1 is driven by so-called frame inversion. Each pixel of the liquid crystal display device 1 displays two grayscales (black and white). However, by providing a color filter and using an area grayscale method, color display can be performed. The liquid crystal display device 1 displays black when no voltage is applied (including when a voltage lower than the threshold voltage is applied).

[0257] like Fig.24 As shown, the pixel 1PX includes a gate line output GL, a source line output SL, a liquid crystal capacitor CLc, analog switches 33, 34, and inverters 35, 36. The liquid crystal capacitor CLc is composed of a liquid crystal layer 300 provided between a pixel electrode 560 and a common electrode 540, and is configured such that a polarity output OUT is supplied to the pixel electrode 560, and a common output Vcom is supplied to the common electrode 540. The analog switches (33, 34) and the inverters (35, 36) are composed of CMOS circuits.

[0258] The output of the inverter 35 is connected to the input of the inverter 36. The inverters 35 and 36 use the power supply VDD as a High-side power supply and the power supply VSS as a Low-side power supply.

[0259] The analog switch 33 is inserted between the white polarity output VA and the polarity output OUT, and the gate of the PMOS transistor 33a is connected to the output of the inverter 35, and the gate of the NMOS transistor 33b is connected to the input of the inverter 35. The analog switch 34 is inserted between the black polarity output VB and the polarity output OUT, and the gate of the PMOS transistor 34a is connected to the input of the inverter 35, and the gate of the NMOS transistor 34b is connected to the output of the inverter 35.

[0260] Fig.25 This is an example of a schematic waveform diagram of each signal voltage used for driving the liquid crystal display device of Modification 10 and a voltage applied to the liquid crystal layer. Fig.25 The (a) shown in the figure represents the common output Vcom. Fig.25 The (b) shown shows the white polarity output VA, Fig.25 (c) shows the waveform of the black polarity output VB. These voltages can be supplied from a known driver. The common output Vcom is a voltage that oscillates between 0V and Vcom (positive polarity) (the oscillation period is 2 frames (2F)). Fig.25 (d) shown shows the white voltage VLC1 applied to the liquid crystal layer. Fig.25 (e) shows a black voltage VLC2 applied to the liquid crystal layer. The white voltage VLC1 is VA-Vcom, and the black voltage VLC2 is VB-Vcom.

[0261] Furthermore, a reflective liquid crystal display device of the MIP method can be realized by the following configuration.

[0262] Fig.26 This is a circuit diagram showing an example of a circuit configuration of a pixel of a liquid crystal display device according to Modification 10. Fig. 27 This is an example of a schematic waveform diagram of each signal voltage used for driving the liquid crystal display device of Modification 10 and a voltage applied to the liquid crystal layer.

[0263] like Fig.26 As shown, the pixel 1PX has a pixel structure with an SRAM function including three switching elements 41 to 43, a latch unit 44, and a liquid crystal cell 45. Here, the liquid crystal cell 45 means a liquid crystal capacitor generated between a pixel electrode 560 and a common electrode 540 disposed opposite thereto.

[0264] One end of the switching element 41 is connected to the gate line 501, and is given a scanning signal The switch element 41 is turned on (off) to read the data SIG supplied via the gate line 501 . The latch unit 44 is composed of inverters 441 and 442 connected in antiparallel to each other, and holds (latches) a potential corresponding to the data SIG read by the switch element 41 .

[0265] Either one of the switch elements 42 and 43 becomes conductive according to the polarity of the holding potential of the latch unit 44, and the liquid crystal unit 45 applies a common potential (common output) Vcom to the common electrode 540, and supplies a control pulse FRP in phase with the common potential Vcom or a control pulse XFRP in reverse phase to the common potential Vcom to the pixel electrode 560. The node to which the terminals of the switch elements 42 and 43 are connected in common becomes the output node Nout of the pixel circuit.

[0266] Depend on Fig. 27 It can be seen that when the holding potential of the latch part 44 is the negative polarity, the pixel potential of the liquid crystal unit 45 is in phase with the common potential Vcom, so it becomes a black display. When the holding potential of the latch part 44 is the positive polarity, the pixel potential of the liquid crystal unit 45 is in phase with the common potential Vcom, so it becomes a white display.

[0267] In this modification, an example of using SRAM as a memory built into a pixel is given, but SRAM is just an example, and a memory of another structure, such as a DRAM structure, may also be used.

[0268] The active matrix liquid crystal display device of the MIP method can realize display based on the analog display mode and display based on the memory display mode as described above by providing each pixel 1PX with a memory. Moreover, in the case of the memory display mode, the pixel data retained in the memory is used for display, so there is no need to write the signal potential reflecting the grayscale in the frame cycle, so there is an advantage that the power consumption of the liquid crystal display device can be reduced.

[0269] In addition, there is a need to partially rewrite the display screen, that is, to rewrite only a part of the display screen. In this case, it is sufficient to partially rewrite the pixel data. If the display screen is partially rewritten, that is, the pixel data is partially rewritten, it is not necessary to transfer data to the pixels that are not rewritten. Therefore, since the amount of data transmission can be reduced, it also has the advantage of being able to save power for the liquid crystal display device.

[0270] Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples; however, the present invention is not limited to these embodiments.

[0271] (Example 1)

[0272] Fig.28 1 is a schematic plan view showing a liquid crystal display device according to Example 1. Fig.29 1 is a schematic cross-sectional view showing a liquid crystal display device according to Example 1. Fig.30 It is a diagram showing the transmission axis orientation of the polarizing plate of the liquid crystal display device of Examples 1 and 2 and the orientation orientation of the first orientation layer and the second orientation layer. A second substrate 500 having an insulating substrate 510, a reflective layer 520, a planarizing film 530, a common electrode 540, an insulating film 550 and a pixel electrode 560 is prepared, and a first substrate 100 having an insulating substrate 110, a color filter layer 1CF and a photo spacer is prepared. Furthermore, an orientation film material containing polyimide is formed on the first substrate 100 as the above-mentioned rubbing orientation layer polymer and a rubbing treatment is performed to form a first orientation layer 200 (rubbing orientation layer). In addition, an orientation film material containing polyhexyl methacrylate (PHMA) (PHMA) as the above-mentioned orientation film polymer is formed on the second substrate 500 to form a second orientation layer 400 (untreated orientation layer).

[0273] Next, a dispenser draws hot UV light on the second substrate 500 and uses a sealing material to bond the first substrate 100 and the second substrate 500 with the liquid crystal layer 300 sandwiched therebetween to produce a cell. In addition, during the bonding and sealing curing, a mask is used to prevent UV light from irradiating to other than the sealed drawn portion, so as to perform sealing UV curing. In addition, as a liquid crystal material, a positive liquid crystal (Δε=6.9, Δn=0.068) with positive dielectric anisotropy is used.

[0274] Then, the liquid crystal molecules were re-aligned by heating at 130° C. for 40 minutes, thereby obtaining a uniformly uniaxially aligned FFS liquid crystal panel. Furthermore, a linear polarizer 10 was provided on the observation side of the first substrate 100 of the liquid crystal panel obtained above, thereby obtaining Figure 28 to Figure 30The liquid crystal display device 1 of Example 1 shown. When the horizontal right direction of the display surface of the liquid crystal display device 1 is taken as the reference direction (0°) and the counterclockwise direction is taken as positive, the transmission axis direction of the linear polarizer 10 is 0°, the orientation direction of the first orientation layer 200 and the orientation direction of the second orientation layer 400 are 45°, and the extension direction of the slit of the pixel electrode 560 is 52°.

[0275] In Example 1, the first alignment layer 200 is a strongly anchored alignment layer, and the alignment angle anchoring energy of the first alignment layer 200 is 6×10 -3 J / m 2 The second alignment layer 400 is a weakly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 6×10 -6 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0276] In addition, the azimuthal anchoring of the alignment layer used in the examples and comparative examples can be quantified by the following procedure.

[0277] 1) Prepare a reference liquid crystal cell with a liquid crystal layer sandwiched by a reference strong anchoring alignment layer. The reference strong anchoring alignment layer may have an azimuth anchoring energy of 1×10 -3 J / m 2 More specifically, the above-mentioned orientation layer can use commercially available AL1254, AL3046, AL16301 (manufactured by JSR Corporation) or SE2414, SE6414 (manufactured by Nissan Chemical Co., Ltd.). In the examples and comparative examples in this specification, L16301 manufactured by JSR Corporation was used, and the rubbing treatment was performed under the conditions of a stage moving speed of 15 mm / s, a rubbing roller rotation speed of 500 rpm, and a press depth of 0.4 mm.

[0278] 2) A target liquid crystal cell having the same structure as the reference liquid crystal cell was prepared except that the liquid crystal layer was sandwiched by the alignment layers to be used for calculating the azimuthal anchoring energy.

[0279] 3) The voltage-transmittance characteristics (VT characteristics) of the reference liquid crystal cell and the target liquid crystal cell were measured, and the threshold voltage at which the transmittance was 10% was measured.

[0280] 4) Calculate the azimuth anchoring energy A according to the following formula.

[0281] A=2×K 22 / [{(V ths / V thw )-1}×d]

[0282] In addition, K 22 represents the twist elastic constant of the liquid crystal, Vths The threshold voltage of the reference cell at a transmittance of 10% is V thw represents the threshold voltage at which the transmittance of the target liquid crystal cell is 10%, and d represents the cell thickness.

[0283] The maximum reflectivity of the liquid crystal display device of Example 1 is 24.3%, the contrast ratio is 27, and the burn-in brightness ratio is 1.24. The maximum reflectivity of the liquid crystal display device is calculated by measuring the reflectivity while applying a voltage to the liquid crystal display device, and normalizing the highest reflectivity with the reflectivity of the second substrate. In addition, the measurement was performed using CM700d manufactured by Konica Minolta. In the following, the highest reflectivity is recorded as white reflectivity, and the reflectivity during black display is recorded as black reflectivity. The contrast ratio of the liquid crystal display device is calculated by dividing the white reflectivity by the black reflectivity. The burn-in brightness ratio of the liquid crystal display device is that after a 24-hour power-on test of a black and white checkered pattern is performed in the liquid crystal display device, 32 grayscales (where the highest grayscale = 255 grayscales) are displayed on the entire surface, and the brightness ratio of the portion displaying white and the portion displaying black is measured as the burn-in brightness ratio. The brightness is measured using a spectroradiometer SR-UL2 manufactured by Topcontec Nohaus.

[0284] (Example 2)

[0285] Fig.31 1 is a schematic cross-sectional view of a liquid crystal display device according to Example 2. The first substrate 100 is formed with an alignment film material containing PHMA as the alignment film polymer to form a first alignment layer 200 (untreated alignment layer), and the second substrate 500 is formed with an alignment film material containing polyimide as the rubbed alignment layer polymer and subjected to rubbing treatment to form a second alignment layer 400 (rubbed alignment layer). In addition, the same method as in Example 1 is used to obtain a first alignment layer 200 (untreated alignment layer). Fig.30 and Fig.31 A liquid crystal display device 1 according to a second embodiment is shown.

[0286] In Example 2, the first alignment layer 200 is a weakly anchored alignment layer, and the anchoring energy of the alignment angle of the first alignment layer 200 is 6×10 -6 J / m 2 The second alignment layer 400 is a strongly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 6×10 -3 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0287] The maximum reflectivity of the liquid crystal display device 1 of Example 2 is 27.1%, the contrast ratio is 32, and the burn-in brightness ratio is 1.13.

[0288] Here, the common electrode 540 and the pixel electrode 560 (hereinafter, the common electrode and the pixel electrode are collectively referred to as FFS electrodes.) The liquid crystal molecules 310 on the substrate side provided with the FFS electrode are affected by the electric field and are easier to move than the liquid crystal molecules 310 on the substrate side without the FFS electrode, and the liquid crystal molecules 310 on the substrate side without the FFS electrode are difficult to move. In Example 1, the first orientation layer 200 on the substrate (first substrate 100) side without the FFS electrode is a strongly anchored orientation layer. In contrast, in Example 2, since the first orientation layer 200 is a weakly anchored orientation layer, in Example 2, the liquid crystal molecules on the first substrate 100 side that are difficult to move due to the influence of the electric field are easier to move than in Example 1. Therefore, it can be considered that in Example 2, the liquid crystal molecules 310 can move in a wider area than in Example 1, and the reflectivity can be further improved.

[0289] In addition, since the second substrate 500 has the FFS electrode, the electric field strength on the second substrate 500 side is stronger than the electric field strength on the first substrate 100 side. In Example 2, since the second alignment layer 400 on the second substrate 500 side having a stronger electric field strength than that on the first substrate 100 side is a strongly anchored alignment layer, it is considered that screen burn-in can be improved compared with Example 1.

[0290] (Example 3)

[0291] Fig.32 1 is a schematic cross-sectional view showing a liquid crystal display device according to Example 3. Fig.33 1 is a diagram showing the transmission axis orientation of the polarizing plate, the orientation orientation of the first and second orientation layers, and the slow axis orientation of the λ / 2 plate of the liquid crystal display device of Examples 3 and 4. After the orientation orientation of the first orientation layer 200 and the second orientation layer 400 is changed and a liquid crystal panel is obtained, the same method as in Example 1 is used except that the λ / 2 plate 11 is provided on the viewing surface side of the first substrate 100. Fig.32 as well as Fig.33 The liquid crystal display device 1 of Example 3 shown. When the horizontal right direction of the display surface of the liquid crystal display device 1 is taken as the reference direction (0°) and the counterclockwise direction is taken as positive, the transmission axis direction of the linear polarizer 10 is 0°, the slow axis direction of the λ / 2 plate 11 is 15°, the orientation direction of the first orientation layer 200 and the orientation direction of the second orientation layer 400 are 75°, and the extension direction of the slit of the pixel electrode 560 is 85°.

[0292] In Example 3, the first alignment layer 200 is a strongly anchored alignment layer, and the alignment angle anchoring energy of the first alignment layer 200 is 6×10 -3 J / m 2 The second alignment layer 400 is a weakly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 6×10-6 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0293] The maximum reflectivity of the liquid crystal display device of Example 3 is 24.1%, the contrast is 75, and the burn-in brightness ratio is 1.24. In Example 3, by providing the λ / 2 plate 11 between the first substrate 100 and the linear polarizer 10, the contrast can be improved compared with Example 1.

[0294] (Example 4)

[0295] Fig.34 1 is a schematic cross-sectional view of a liquid crystal display device according to Example 4. The first substrate 100 is formed with an alignment film material containing PHMA as the alignment film polymer to form a first alignment layer 200 (untreated alignment layer), and the second substrate 500 is formed with an alignment film material containing polyimide as the rubbed alignment layer polymer and rubbed to form a second alignment layer 400 (rubbed alignment layer). In addition, the same method as in Example 3 is used to obtain the alignment film. Fig.33 and Fig.34 A liquid crystal display device 1 according to a fourth embodiment is shown.

[0296] In Example 4, the first alignment layer 200 is a weakly anchored alignment layer, and the alignment angle anchoring energy of the first alignment layer 200 is 6×10 -6 J / m 2 The second alignment layer 400 is a strongly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 6×10 -3 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0297] The maximum reflectivity of the liquid crystal display device 1 of Example 4 is 27.0%, the contrast ratio is 91, and the burn-in brightness ratio is 1.13. Example 4 can improve the reflectivity and screen burn-in by using the first orientation layer 200 and the second orientation layer 400 of Example 2, and can improve the contrast by using the λ / 2 plate 11 configured in Example 3.

[0298] (Comparative Example)

[0299] Fig.35 1 is a schematic cross-sectional view showing a liquid crystal display device of a comparative example. Fig.36The figure shows the transmission axis orientation of the polarizing plate, the orientation orientation of the first and second orientation layers, and the slow axis orientation of the λ / 2 plate of the liquid crystal display device of the comparative example. The second orientation layer 400 (rubbed orientation layer) is formed by forming an orientation film material containing polyimide as the above-mentioned rubbed orientation layer polymer on the second substrate 500 and performing a rubbing treatment. In addition, the same method as in Example 3 is used to obtain Fig.35 and Fig.36 The liquid crystal display device 1R of the embodiment shown.

[0300] In the comparative example, the first alignment layer 200 and the second alignment layer are both strongly anchored alignment layers, and the anchoring energy of the orientation angle is 6×10 -3 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0301] The liquid crystal display device of the comparative example had a maximum reflectivity of 20.5%, a contrast ratio of 23, and a burn-in brightness ratio of 1.04.

[0302] (Evaluation of Examples 3, 4 and Comparative Examples)

[0303] The maximum reflectivity of the liquid crystal display device is 20.5% in the comparative example, while it is 24.1% in the embodiment 3 and 27.0% in the embodiment 4. In the embodiments 3 and 4, in the reflective liquid crystal display device of the FFS mode, by setting one of the first orientation layer 200 and the second orientation layer 400 as a weakly anchored (zero-plane anchoring, smooth interface) orientation layer, and setting the orientation of the substrate on one side as a weak anchor, it is believed that the liquid crystal molecules 310 near the existing immovable substrate can be moved, and it is possible to increase the △nd modulation width of the liquid crystal layer 300. As a result, in the embodiments 3 and 4, a reflectivity higher than that of the comparative example can be achieved, and it is believed that a high reflectivity comparable to the longitudinal electric field mode can be obtained. In addition, in the embodiments 3 and 4, a high reflectivity can be achieved while achieving low voltage.

[0304] Fig.37 , Fig.38 as well as Fig.39 These are simulation results for calculating the alignment states of liquid crystal molecules in the liquid crystal display devices of the comparative example, Examples 3, and 4, respectively. Fig.40 This is a diagram showing simulation results for calculating the magnitude of the displacement angle of the liquid crystal molecules in the liquid crystal display devices of Examples 3 and 4 and the comparative example with respect to the thickness direction of the liquid crystal layer.

[0305] Regarding the liquid crystal display devices of Examples 3, 4 and the comparative example, the alignment state of the liquid crystal molecules was simulated using LCD-MASTER manufactured by Sintec. However, in Example 3, the azimuthal anchoring energy of the first alignment layer 200 was set to 1×10- 3 J / m 2 , the azimuthal anchoring energy of the second alignment layer 400 is set to 1×10 -7 J / m 2 In Example 4, the azimuthal anchoring energy of the first alignment layer 200 is set to 1×10 -7 J / m 2 , the azimuthal anchoring energy of the second alignment layer 400 is set to 1×10 -3 J / m 2 In the comparative example, the azimuthal anchoring energy of the first alignment layer 200 and the second alignment layer 400 is set to 1×10 -3 J / m 2 The results are shown in Figures 37 to 40 .

[0306] like Fig.37 As shown in FIG. 1 , in the comparative example, the liquid crystal molecules 310 rotate only in the middle region in the thickness direction of the liquid crystal layer 300, so the modulation width of the in-plane phase difference Δnd cannot be sufficiently increased. Therefore, the reflective layer 520 does not become an ideal linear polarized light, the reflectivity becomes low, and a sufficiently bright state is not achieved.

[0307] On the other hand, in Example 3, Fig.38 As shown, the liquid crystal molecules near the interface on the second substrate 500 side, which are weakly anchored, also rotate in the plane, so that the modulation width of the in-plane phase difference Δnd can be increased, and the reflectivity can be improved.

[0308] In addition, in Example 4, Fig.39 As shown in FIG. 1 , by setting the first substrate 100 side to be weakly anchored, the liquid crystal molecules 310 at the interface on the first substrate 100 side also rotate in the plane. Fig.40 As shown, there is a maximum displacement position of the liquid crystal molecules from the center of the thickness direction of the liquid crystal layer 300 to the FFS electrode side. Therefore, when the first substrate 100 side is set as weak anchor, the liquid crystal molecules 310 in a wider area can be driven compared to when the second substrate 500 side provided with the FFS electrode is set as weak anchor. Therefore, in Example 4, it is considered that a liquid crystal display device with a better reflectivity than that of Example 3 is obtained. In addition, since the modulation width of the phase difference Δnd of the liquid crystal layer 300 is large in the configuration in which the first substrate 100 side is set as weak anchor, when the liquid crystal display device has a transmission area, the thickness of the liquid crystal layer 300 in the transmission area can be made smaller than that of the conventional FFS mode liquid crystal display device, which is an advantageous configuration in terms of response speed.

[0309] Fig.41Graph showing VR characteristics of the liquid crystal display devices of Examples 3 and 4 and the comparative example. The voltage dependence characteristics of reflectivity (VR characteristics) were measured for the liquid crystal display devices of Examples 3 and 4 and the comparative example. The measurement was performed using CM700d manufactured by Konica Minolta. The results are shown in Fig.41 middle.

[0310] like Fig.41 As shown, in Examples 3 and 4, it can be confirmed that the voltage is lowered and the reflectivity is improved compared to the comparative example. In Example 3, a liquid crystal display device with lower voltage and excellent power consumption can be obtained. In Example 4, a liquid crystal display device with higher reflectivity and excellent brightness can be obtained.

[0311] (Example 5)

[0312] Fig.42 1 is a schematic cross-sectional view showing a liquid crystal display device of Example 5. Fig.43 : is a diagram showing the transmission axis orientation of the polarizing plate, the orientation orientation of the first orientation layer and the second orientation layer, and the slow axis orientation of the λ / 2 plate of the liquid crystal display device of Example 5. A second substrate 500 having an insulating substrate 510, a reflective layer 520, a color filter layer 1CF, a planarization film 530, a common electrode 540, an insulating film 550, and a pixel electrode 560, and a first substrate 100 having an insulating substrate 110 and a photo spacer are prepared. On the first substrate 100, as the above-mentioned photo-alignment polymer, a polyamic acid represented by the above-mentioned chemical formula (A) (wherein R in the chemical formula (A) is 1 , R 2 , R 3 and R 4 is a hydrogen atom or a hydrocarbon group, X 1 is a tetravalent organic group containing a cyclobutane ring, Y 1 An alignment film material (a divalent organic group containing a methacrylate group).

[0313] Furthermore, an alignment film material (decomposable photo-alignment film material) containing a photo-degradable polymer as the photo-alignment polymer is formed on the second substrate 500. After the film is formed, the film surface is irradiated with linearly polarized ultraviolet rays using a 254 nm bandpass filter for alignment treatment, thereby forming a second alignment layer 400 (photo-alignment layer) provided on the second substrate 500.

[0314] Next, a dispenser draws hot UV light on the second substrate 500 and uses a sealing material to bond the first substrate 100 and the second substrate 500 with the liquid crystal layer 300 sandwiched therebetween to produce a unit. In addition, during the bonding and sealing curing, a mask is used to prevent UV light from irradiating to other than the sealed drawn portion, so as to perform sealing UV curing. In addition, as a liquid crystal material, a material in which an additive represented by the following chemical formula (L1) is added in an amount of 5 wt % to a positive liquid crystal (Δε=6.9, Δn=0.068) having a positive dielectric anisotropy is used.

[0315] [Chemistry 3]

[0316]

[0317] Then, the liquid crystal molecules were realigned by heating at 130° C. for 40 minutes, thereby obtaining a uniformly uniaxially aligned FFS liquid crystal panel. The obtained liquid crystal panel was irradiated with 10 J / cm2 of UVB having a main wavelength of 313 nm from the first substrate 100 side. 2 , forming the first alignment layer 200 (photo-alignment layer). Then, a λ / 2 plate 11 and a linear polarizer 10 are provided on the observation side of the first substrate 100, and Fig.42 and Fig.43 The liquid crystal display device of Example 5 shown. When the horizontal right direction of the display surface of the liquid crystal display device 1 is taken as the reference direction (0°) and the counterclockwise direction is taken as positive, the transmission axis direction of the linear polarizer 10 is 0°, the slow axis direction of the λ / 2 plate 11 is 15°, the orientation direction of the first orientation layer 200 and the orientation direction of the second orientation layer 400 are 75°, and the extension direction of the slit of the pixel electrode 560 is 85°.

[0318] In Example 5, the first alignment layer 200 is a weakly anchored alignment layer, and the alignment angle anchoring energy of the first alignment layer 200 is 2×10 -7 J / m 2 The second alignment layer 400 is a strongly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 1×10 -3 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0319] The maximum reflectivity of the liquid crystal display device of Example 5 is 29.0%, the contrast ratio is 95, and the burn-in brightness ratio is 1.07. In Example 5, the first substrate 100 side is set as a weakly anchored orientation layer, and the second substrate 500 side is set as a strongly anchored one, but in the comparative example, both substrate sides are set as strongly anchored. Therefore, in Example 5, the orientation restriction force of the orientation layer on the liquid crystal molecules is weaker than that in the comparative example, and the movable area of ​​the liquid crystal molecules can be expanded at a lower voltage. As a result, it is believed that Example 5 can improve the reflectivity at a lower voltage relative to the comparative example. In addition, in Example 5, the orientation restriction force of the orientation layer on the liquid crystal molecules is weaker than that in the comparative example, so the movable area of ​​the liquid crystal molecules can be further expanded, and the reflectivity can be improved compared with the comparative example.

[0320] In addition, in Examples 3 and 5, the materials constituting the weak anchoring layer are different from each other. In Example 5, screen burn-in and reflectivity can be improved compared with Example 3. In Example 5, the second alignment layer 400 is formed by additional irradiation using an additive contained in the liquid crystal layer 300. Compared with forming the alignment layer only by the alignment film material as in Example 3, when the alignment layer is formed by using the additive added to the liquid crystal layer 300 and additional irradiation, the material variation is also wider, and a liquid crystal display device with better reflectivity can be obtained. The structure of Example 5 requires additional irradiation, and the first substrate 100 side needs to transmit ultraviolet rays. Therefore, the reflective layer 520 and the color filter layer 1CF need to be arranged on the second substrate 500.

[0321] (Example 6)

[0322] Fig.44 1 is a schematic cross-sectional view showing a liquid crystal display device of Example 6. Fig.45 : is a diagram showing the transmission axis orientation of the polarizing plate, the orientation orientations of the first and second orientation layers, and the slow axis orientation of the λ / 2 plate of the liquid crystal display device of Example 6. The same method as in Example 5 was used except that the orientation orientations of the first and second orientation layers and the phase difference Δnd of the liquid crystal layer 300 were changed and a chiral agent was added to the liquid crystal layer. Fig.44 as well as Fig.45 The liquid crystal display device 1 of Example 6 shown. When the horizontal right direction of the display surface of the liquid crystal display device 1 is taken as the reference direction (0°) and the counterclockwise direction is taken as positive, the transmission axis direction of the linear polarizer 10 is 0°, the slow axis direction of the λ / 2 plate 11 is 15°, the orientation direction of the first orientation layer 200 is 135°, the orientation direction of the second orientation layer 400 is 65°, and the extension direction of the slit of the pixel electrode 560 is 110°.

[0323] In Example 6, the first alignment layer 200 is a weakly anchored alignment layer, and the anchoring energy of the alignment angle of the first alignment layer 200 is 2×10 -7 J / m 2The second alignment layer 400 is a strongly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 1×10 -3 J / m 2 . In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective area is 250nm. In addition, the chiral pitch of the liquid crystal layer is 13.9μm. As in Examples 1 to 5, when the orientation direction of the first orientation layer 200 is parallel to the orientation direction of the second orientation layer 400, the phase difference Δnd of the liquid crystal layer 300 is preferably around 137.5nm, and as in Example 6, when the orientation direction of the first orientation layer 200 is not parallel to the orientation direction of the second orientation layer 400, the phase difference Δnd of the liquid crystal layer 300 is preferably around 250nm.

[0324] The maximum reflectivity of the liquid crystal display device of Example 6 is 25.2%, the contrast ratio is 25, and the burn-in brightness ratio is 1.07. In Example 6, the first substrate 100 side is set as a weakly anchored orientation layer, and the second substrate 500 side is set as a strongly anchored side, but in the comparative example, both substrate sides are set as strongly anchored. Therefore, in Example 6, the orientation restriction force of the orientation layer on the liquid crystal molecules is weaker than that of the comparative example, and the movable area of ​​the liquid crystal molecules can be expanded at a lower voltage. As a result, it is believed that Example 6 can improve the reflectivity at a lower voltage relative to the comparative example. In addition, in Example 6, compared with the comparative example, the orientation restriction force of the orientation layer on the liquid crystal molecules 310 is weaker, so the movable area of ​​the liquid crystal molecules 310 can be further expanded, and the reflectivity can be improved compared with the comparative example.

[0325] In addition, even if it is assumed that there is a deviation in the unit thickness and the phase difference Δnd of the liquid crystal layer 300, in Example 6, since the liquid crystal molecules 310 are twisted and oriented, the deviation in the polarization state on the reflective layer 520 can be suppressed, and a liquid crystal display device with excellent product quality can be obtained.

[0326] In addition, by using a chiral agent that rotates in a direction opposite to that of the liquid crystal molecules 310 included in the liquid crystal layer 300 when the voltage is turned on, the response speed can be improved.

[0327] Furthermore, the present invention is not limited to the embodiment of the present invention, and a λ / 2 plate or a λ / 4 plate may be appropriately inserted.

[0328] (VR Characteristics of Examples 1 to 6, Comparative Examples, and Reference Examples)

[0329] Fig.46 This is an example VR characteristics of liquid crystal display devices of comparative examples and reference examples. Based on the above-mentioned embodiments 1 to 6 and comparative examples, VR characteristics of liquid crystal display devices of the longitudinal electric field mode used in existing reflective liquid crystal display devices were also measured. Fig.46 The results are shown in .

[0330] The conventional transverse electric field mode reflective liquid crystal display device (comparative example) has a poor reflectivity compared to the current longitudinal electric field mode reflective liquid crystal display device (reference example), and is therefore not suitable for use in products. However, in Examples 1 to 6, reflectivities comparable to the longitudinal electric field mode reference example were obtained.

[0331] (Example 7)

[0332] Fig.47 1 is a cross-sectional schematic diagram showing a liquid crystal display device of Example 7. A liquid crystal display device 1 of Example 7 corresponding to Modification Example 10 was manufactured. Specifically, Fig.47 As shown, as the second substrate 500, a MIP driven TFT substrate is prepared, which has a reflective layer 520, a color filter layer 1CF, a photosensitive spacer, and a common electrode 540 and a pixel electrode 560 with an FFS electrode structure, and each pixel 1PX has a storage circuit (storage circuit unit) 30M and a display voltage supply circuit (display voltage supply circuit unit) 30D.

[0333] Each pixel 1PX is as follows Fig.21 As shown, it is divided into three sub-pixels (first sub-pixel 21PX, second sub-pixel 22PX and third sub-pixel 23PX). However, in each pixel 1PX, the first sub-pixel 21PX and the third sub-pixel 23PX are connected to each other, and are actually divided into two with an area ratio of 1:2. Thus, 4 grayscales × 4 grayscales × 4 grayscales = 64 colors can be displayed.

[0334] Furthermore, on the first substrate 100, a polyamic acid having the chemical formula (A) is prepared (wherein R 1 , R 2 , R 3 and R 4 is a hydrogen atom or a hydrocarbon group, X 1 is a tetravalent organic group containing a cyclobutane ring, Y 1 In addition, the same decomposable photo-alignment film material as that in Example 5 is formed on the second substrate 500 .

[0335] Next, a dispenser draws hot UV light on the second substrate 500 and uses a sealing material to laminate the first substrate 100 and the second substrate 500 with the liquid crystal layer 300 sandwiched therebetween to produce a unit. In addition, during the lamination and sealing and curing, a mask is used to prevent UV light from irradiating to other than the sealed drawn portion, so as to perform sealing UV curing. In addition, as a liquid crystal material, a material in which 0.5 wt% of hexyl methacrylate represented by the above chemical formula (L1) is added to a positive liquid crystal (Δε=6.9, Δn=0.068) having a positive dielectric anisotropy is used.

[0336] Thereafter, the liquid crystal molecules were realigned by heating at 130° C. for 40 minutes, thereby obtaining a uniformly uniaxially aligned FFS liquid crystal panel. The obtained liquid crystal panel was irradiated with UVB having a main wavelength of 313 nm at 1 J / cm2 from the first substrate 100 side. 2 , forming the first alignment layer 200 (photo-alignment layer). Then, a λ / 2 plate 11 and a linear polarizer 10 are provided on the observation side of the first substrate 100, and Fig.47 The liquid crystal display device of Example 7 is shown. The axis arrangement of the polarizing plate or the λ / 2 plate is set in the same manner as in Example 5 described above.

[0337] In Example 7, the first alignment layer 200 is a weakly anchored alignment layer, and the anchoring energy of the alignment angle of the first alignment layer 200 is 2×10 -7 J / m 2 The second alignment layer 400 is a strongly anchored alignment layer, and the anchoring energy of the alignment angle of the second alignment layer 400 is 1×10 -3 J / m 2 In addition, the phase difference Δnd of the liquid crystal layer 300 in the reflective region is 137.5 nm.

[0338] In addition, the maximum reflectivity of the liquid crystal display device of Example 7 is 28.2%, the contrast ratio is 91, and the burn-in brightness ratio is 1.04.

[0339] Here, regarding the burn-in brightness ratio of the liquid crystal display device in Example 7, the minimum grayscale (black / black / black) is displayed on half of the liquid crystal display device, and the maximum grayscale (white / white / white) is tested on the other half for 24 hours, and then the grayscale (black / white / black) is displayed on the entire surface, and the brightness ratio of the portion showing the maximum grayscale and the portion showing the minimum grayscale is measured as the burn-in brightness ratio. The burn-in test of the TFT-driven reflective liquid crystal display device is as described in the above-mentioned Example 1. Since this embodiment is driven by MIP, there is no grayscale such as 32 grayscales. Therefore, the burn-in brightness ratio is obtained by this method.

[0340] In the area grayscale driving of Example 7, only white and black are displayed as a sub-pixel (intermediate grayscale is displayed as the area ratio of black and white). Both white and black are located at the saturation point in the curve diagram representing VR characteristics, so even if screen burn-in occurs, there is no brightness difference, and screen burn-in is not easily observed.

[0341] In order to confirm this principle, a liquid crystal element was prepared that could measure the reflected brightness while oscillating the voltage carefully. In addition, the material of the orientation layer and the configuration of the optical axis were made in the same way as in Example 7. When the VR characteristics were evaluated before and after the test using this liquid crystal element, the results were as follows: Fig.48 shown. Fig.48: is a graph showing the VR characteristics of the MIP type liquid crystal display device. It can be seen that the reflectivity difference increases before and after the voltage of 2V. On the other hand, it can be seen that there is almost no reflectivity difference near 0V and 3V. Based on this result, in the MIP type reflective element of this embodiment, the intermediate gray scale is displayed with a combination of black (0V) and white (3.2V), so it is considered that screen burn-in is suppressed.

[0342] In addition, from the perspective of the magnitude of the driving voltage, the comparative example also needs to apply a voltage of 5V, but the weakly anchored liquid crystal element including this embodiment can be around 3V to 3.5V. If the driving voltage is reduced, the accumulation of charge is suppressed, that is, the change in VR characteristics is also suppressed, and the afterimage can be suppressed. In order to achieve such a low-voltage drive, it is preferred to use a high Δε liquid crystal with Δε≥5.

[0343] In addition, Example 7 corresponds to the above-mentioned embodiment 1 in which the first orientation layer 200 is a weakly anchored orientation layer and the second orientation layer 400 is a strongly anchored orientation layer, but in the above-mentioned embodiment 2 in which the first orientation layer 200 is a strongly anchored orientation layer and the second orientation layer 400 is a weakly anchored orientation layer, and in the above-mentioned embodiment 3 in which the first orientation layer 200 and the second orientation layer 400 are weakly anchored orientation layers, by applying the MIP type of Example 7, the same effect as Example 7 can be obtained.

[0344] (Study on azimuth anchoring energy)

[0345] LCD-MASTER manufactured by Suntech was used to simulate how the reflectivity of the liquid crystal display device changes depending on the azimuth anchoring energy of the weakly anchored orientation layer in a configuration equivalent to Example 2 (the first orientation layer 200 is a weakly anchored orientation layer). The results are shown in Table 1 below. The maximum reflectivity of the reflective liquid crystal display device in the longitudinal electric field mode as a reference example is 26%. In Table 1, the portion with a maximum reflectivity exceeding 26% is judged as OK (○), and the portion with a maximum reflectivity of more than 90% of the reference example, that is, more than 23.4% and less than 26%, is judged as OK (△) that can be used in practice.

[0346] [Table 1]

[0347]

[0348] According to Table 1, by making the azimuthal anchoring energy of one of the alignment layers less than 1×10 -4 J / m 2 , which can improve the reflectivity by making the azimuthal anchoring energy less than 1×10 -5 J / m 2 , which can further improve the reflectivity.

[0349] Description of Reference Numerals

[0350] 1.1R: Liquid crystal display device

[0351] 1CF: Color filter layer

[0352] 1PX: Pixel

[0353] 1PXB: Blue Pixel

[0354] 1PXG: Green Pixel

[0355] 1PXR: Red Pixel

[0356] 21PX, 21PXB, 21PXG, 21PXR: First sub-pixel

[0357] 22PX, 22PXB, 22PXG, 22PXR: Second sub-pixel

[0358] 23PX, 23PXB, 23PXG, 23PXR: Third sub-pixel

[0359] 2PX: Sub-Pixel

[0360] 10, 20: Linear polarizer

[0361] 11: λ / 2 plate

[0362] 12: λ / 4 plate

[0363] 21: Phase difference layer

[0364] 30: Backlight

[0365] 30D: Display voltage supply circuit (display voltage supply circuit portion)

[0366] 30M: memory circuit (memory circuit unit)

[0367] 33, 34: Analog switch

[0368] 33a, 34a: PMOS transistors

[0369] 33b, 34b: NMOS transistors

[0370] 35, 36, 441, 442: Inverter

[0371] 41, 42, 43, 443: Switching elements

[0372] 44: Latch unit

[0373] 45: Liquid crystal unit

[0374] 100: First substrate

[0375] 110, 510: Insulating substrate

[0376] 200: First orientation layer

[0377] 300: Liquid crystal layer

[0378] 310: Liquid crystal molecules

[0379] 400: Second orientation layer

[0380] 500: Second substrate

[0381] 501: Gate line

[0382] 502: Source line

[0383] 503: Thin Film Transistor (TFT)

[0384] 505: Gate

[0385] 506: Source

[0386] 507: Semiconductor layer

[0387] 508: Drain

[0388] 509: Contact hole

[0389] 520: Reflective layer

[0390] 530: Flattening film

[0391] 531: Ladder control layer

[0392] 540: Shared Electrode

[0393] 550: Insulation film

[0394] 560: Pixel electrode

[0395] CLc: Liquid crystal capacitance

[0396] FRP, XFRP: Controlled Pulse

[0397] GL: Gate line output

[0398] Nout: output node

[0399] OUT: Polarity output

[0400] R: Reflective area

[0401] SIG: Data

[0402] SL: Source line output

[0403] T: Transmission area

[0404] V: White polarity output

[0405] VB: Black polarity output

[0406] Vcom: Common output (common potential)

[0407] VDD, VSS: power supply

[0408] φV (φV1~φVm): Operation signal

Claims

1. A liquid crystal display device, characterized in that: Include in the following order: a first substrate; a first orientation layer; a liquid crystal layer comprising liquid crystal molecules that are horizontally aligned when no voltage is applied; a second orientation layer; The second substrate has a pixel electrode and a common electrode, and further includes: a reflective layer disposed on at least a portion of the pixel on the back side relative to the first alignment layer, the liquid crystal layer, the second alignment layer, the pixel electrode, and the common electrode; The azimuthal anchoring energy of at least one of the first alignment layer and the second alignment layer is less than 1×10 - 4 J / m 2 , The azimuthal anchoring energy of the first alignment layer is less than 1×10 -4 J / m 2 , The azimuthal anchoring energy of the second alignment layer is less than 1×10 -4 J / m 2 , The pixel has a reflective region provided with the reflective layer and a transmissive region not provided with the reflective layer, The liquid crystal layer has a phase difference in the transmission region of not less than 220 nm and not more than 320 nm.

2. The liquid crystal display device according to claim 1, wherein: The azimuthal anchoring energy of the first alignment layer is less than 1×10 -5 J / m 2 .

3. The liquid crystal display device according to claim 1 or 2, characterized in that: The second substrate further includes a color filter.

4. The liquid crystal display device according to claim 3, characterized in that: At least one of the first alignment layer and the second alignment layer comprises a polymer having the following groups: at least one first photofunctional group selected from cyclobutyl, azophenyl, chalcone, cinnamate, coumarin, stilbene, phenolic ester, and phenylbenzoate; at least one second photofunctional group selected from acrylate, methacrylate, cinnamoyl, coumarin, vinyl, allyl, styryl, and maleimide, The liquid crystal layer includes an additive having at least one group selected from an acrylate group, a methacrylate group, a cinnamoyl group, a coumarin group, a vinyl group, an allyl group, a styrene group, and a maleimide group.

5. The liquid crystal display device according to claim 1 or 2, characterized in that: A λ / 2 plate is also included.

6. The liquid crystal display device according to claim 1 or 2, characterized in that: A λ / 4 plate is also included.

7. The liquid crystal display device according to claim 1 or 2, characterized in that: The pixel has a plurality of sub-pixels.

8. The liquid crystal display device according to claim 1 or 2, characterized in that: The pixel has a storage circuit.

9. The liquid crystal display device according to claim 1 or 2, characterized in that: further comprising a λ / 4 plate, The orientation direction of the first orientation layer is parallel to the orientation direction of the second orientation layer, The liquid crystal layer has a phase difference of 80 nm or more and 180 nm or less in a region overlapping the reflective layer.

10. The liquid crystal display device according to claim 1 or 2, characterized in that: The orientation direction of the first orientation layer is parallel to the orientation direction of the second orientation layer, The liquid crystal layer has a phase difference of 130 nm to 145 nm in a region overlapping the reflective layer.

11. The liquid crystal display device according to claim 1 or 2, characterized in that: The orientation direction of the first orientation layer is not parallel to the orientation direction of the second orientation layer, The liquid crystal layer has a phase difference of 240 nm to 260 nm in a region overlapping the reflective layer.

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