Liquid crystal display device

Abstract

Provided is a liquid crystal display device capable of achieving high-speed response, high transmittance and contrast, and excellent viewing angle characteristics in both rising and falling. The liquid crystal display device performs color display in a plurality of subframe periods included in one frame period by field sequential driving, and includes: a liquid crystal display panel; a light source that irradiates the liquid crystal display panel with light of a plurality of colors; and a controller that drives the light source so that light of the plurality of colors is irradiated to the liquid crystal display panel in time division, the liquid crystal display panel successively having: a first substrate having a pixel electrode, a first alignment film, a liquid crystal layer, a second alignment film, and a second substrate having a common electrode, the liquid crystal layer having a first domain and a second domain in which alignment vectors are different from each other when no voltage is applied, when the alignment vectors are defined with a long axis end portion of the first substrate side of the liquid crystal molecules as a start point and a long axis end portion of the second substrate side as an end point.

Description

Technical Field

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

[0002] Liquid crystal display (LCD) devices utilize liquid crystal compositions for display. A typical display method involves illuminating a liquid crystal panel formed by sealing a liquid crystal composition between a pair of substrates with light from a backlight, and applying a voltage to the liquid crystal composition to change the orientation of the liquid crystal molecules, thereby controlling the amount of light transmitted through the liquid crystal panel. Such LCD devices are characterized by their thinness, light weight, and low power consumption, and are used in a wide range of fields.

[0003] In recent years, Field Sequential Color (FSC) has been developed as one of the driving methods for liquid crystal display devices that display color images. A typical FSC method works as follows: the display period of a single frame is divided into three subframes. The red (R), green (G), and blue (B) LEDs (Light Emitting Diodes) that serve as backlight sources are switched in a time-division multiplexing manner. Simultaneously, image signals corresponding to the colors of the light emitted by each LED are sequentially provided to the liquid crystal display panel. The transmission state of these signals is controlled, and additive color mixing is performed on the retina of the observer's eye.

[0004] According to the FSC method, color display can be performed without forming multiple subpixels in a single pixel, thus eliminating the need for color filters and enabling high resolution. Furthermore, since light from LEDs is used directly, there is no need to form high-absorption color filters in each pixel, improving the light utilization efficiency of each LED.

[0005] However, in recent years, devices for transparent displays (perspective displays) that allow a transparent background to be seen have been developed for use as information displays or digital signage. Such displays are also called transparent displays, but in a transparent display, the background, i.e., the back side of the display panel, appears transparent. Therefore, it is possible to display information on the display panel while overlapping the background. This achieves a new display capability that was previously impossible in existing display devices.

[0006] As a technology related to transparent displays using the FSC method, for example, Patent Document 1 discloses a technique for controlling the subframe period for the purpose of suppressing unexpected color changes in the column called a color filter, and describes the ability to apply the control of the subframe period to a transparent display device using a polymer-dispersed liquid crystal.

[0007] Existing technical documents

[0008] Patent documents

[0009] Patent Document 1: Japanese Patent Application Publication No. 2021-15154 Summary of the Invention

[0010] The technical problem to be solved by the present invention

[0011] As described above, liquid crystal display devices using the FSC method are known. Recently, a device has also been developed that uses the FSC method as the driving method and employs a TN (Twisted Nematic) mode panel as the liquid crystal display panel, which has a structure in which the liquid crystal molecules are twisted 90 degrees in the long axis direction between the element substrate and the opposing substrate. The inventors have investigated various physical properties of this device as follows (see also Comparative Example 1 described below).

[0012] Figure 1 In the diagram, response waveform (b) shows the results of analyzing the response characteristics of a liquid crystal display device using a TN mode liquid crystal display panel. Figure 1 In the diagram, the horizontal axis is set to time (m seconds), and the vertical axis is set to the normalized brightness (normalized transmittance) when the waveform input is on-off-off (monochrome display). The light source is lit in the order of red (R), blue (B), and green (G). Figure 1 It is known that in TN mode, the transition (decrease) from white display state (bright state) to black display state (dark state) is fast. Therefore, it is advantageous in terms of color gamut (NTSC ratio). However, the transition (rise) from black display state (dark state) to white display state (bright state) is slow, which is disadvantageous in terms of brightness in monochrome display.

[0013] Figure 2A and Figure 2B This study examines the brightness (normalized brightness) of monochrome displays in liquid crystal display devices using TN mode liquid crystal display panels. Figure 2A This is a graph evaluating the brightness of a monochrome display based on the brightness when displaying white (white brightness). When white brightness is set to 100%, the percentages of the total brightness for red (R), green (G), and blue (B) are 57% (32% + 13% + 12%), 56% (15% + 37% + 3%), and 78% (0% + 7% + 70%), respectively. Note that the brightness values ​​within parentheses are recorded after discarding decimal places from the measured values. Furthermore, since the total brightness is calculated directly using measured values, some of the calculated values ​​may appear inconsistent.

[0014] Figure 2B This shows a display image from the device. (By...) Figure 2A It is known that the brightness of the monochrome display in this device is low; therefore, in Figure 2B In the image, the flowers and leaves of hibiscus plants are displayed as dull, pale colors. On the other hand, the white parts of the clouds and flowers do not show any reduction in brightness. Thus, in TN mode, the brightness changes according to the colors of the image, with the more RGB primary colors appearing darker, resulting in an unnatural display that disrupts the brightness balance.

[0015] Figure 3A and Figure 3B This is the result of evaluating the viewing angle characteristics of a liquid crystal display device using a TN mode liquid crystal display panel. Details will be explained in Comparative Examples 1-3, which display a color original image and capture images of the displayed image from various angles using a camera. Assuming high viewing angle priority (i.e., desktop use with the monitor viewed from above), it is evident that a downward-facing black-and-white inverted image is obtained. Furthermore, at an azimuth angle of -135 degrees (… Figure 3A , Figure 3B (each in the lower left), -90 degrees Figure 3A , Figure 3B (each at the bottom center) and -45 degrees ( Figure 3A , Figure 3B In the lower right corner of each area, black spots appear (referring to areas that darken in the same way as the dark areas), and further, grayscale inversion occurs (referring to the phenomenon of brightness inversion in grayscale display). Thus, there is room for improvement in viewing angle characteristics in TN mode.

[0016] Figure 4A , Figure 4B , Figure 4C and Figure 5 The results of studying transmittance, color gamut, and liquid crystal alignment are presented for two liquid crystal display devices: (b) using a TN mode liquid crystal display panel and a liquid crystal display device (c) using a TV liquid crystal material with no alignment separation in the liquid crystal layer and a liquid crystal display panel driven by an FSC for color display. Furthermore, all conditions (FSC driving conditions, etc.) are set to be the same, except for the liquid crystal display panel used (liquid crystal alignment mode).

[0017] Figure 4A This is a schematic diagram showing the orientation of liquid crystal molecules during light transmission in a portion of the liquid crystal layer within a pixel where the thickness (cell thickness) is at an intermediate value. To easily illustrate the tilt orientation of the liquid crystal molecules 210, a pin (cone) is used to represent the liquid crystal molecules 210, with the base of the cone representing the observer side and the apex representing the back side. In 1D-VA mode, the orientation is as shown in Figure 4 when a voltage is applied; in TN mode, the orientation is as shown in Figure 4 when no voltage is applied. Figure 4AThe dashed line 'p' in the diagram represents the edge of the pixel electrode. Because light does not transmit sufficiently through this edge, it may create a dark area that is perceived as a line (called a dark line). However, whether the dark line is exposed or covered by a black matrix (BM), it has no effect. Figure 5 The comparison between TN mode (b) and 1D-VA mode (c) is shown. When using a TN mode LCD panel, a light-shielding metal can be used instead of BM to hide dark lines. Figure 4B This is a schematic diagram showing the configuration of the thin-film transistor (TFT) wiring for a pixel. Figure 4C This is a schematic diagram showing the configuration of BM or light-shielding metal.

[0018] Figure 5 In the table, (c) shows the evaluation results of a device using a liquid crystal display panel in 1D-VA mode, and (b) shows the evaluation results of a device using a liquid crystal display panel in TN mode. Each physical property was measured twice (No. 1, No. 2), and their average values ​​are shown in the right column of each. White brightness is used as an indicator of transmittance (mode efficiency), but the white brightness in 1D-VA mode (c) is higher than that in TN mode (b). The contrast ratio is also significantly higher in 1D-VA mode (c) than in TN mode (b). On the other hand, the NTSC ratio, an indicator of color gamut, is very low in 1D-VA mode (c) compared to TN mode (b). Therefore, it is clear that there is room for improvement in transmittance and color gamut when the display mode (liquid crystal alignment mode) of the liquid crystal display panel is changed from TN mode to 1D-VA mode.

[0019] As described above, even for liquid crystal display devices that display colors via FSC driving, there is room for improvement in various physical properties in the various methods described above. Furthermore, in the display device described in Patent Document 1, the transmittance (high mode efficiency) is insufficient, making low power consumption impossible; in addition, the contrast ratio and viewing angle characteristics are also insufficient, and there is room for improvement in these aspects.

[0020] The present invention was made in view of the above-mentioned situation, and its object is to provide a liquid crystal display device that can achieve high-speed response, high transmittance and contrast, and excellent viewing angle characteristics in both rising and falling directions.

[0021] Technical solutions for solving technical problems

[0022] (1) One embodiment of the present invention is a liquid crystal display device that performs color display during a frame period including multiple sub-frame periods by field sequence driving. The liquid crystal display device includes: a liquid crystal display panel; a light source that illuminates the liquid crystal display panel with light of multiple colors; and a controller that drives the light source so that the light of multiple colors illuminates the liquid crystal display panel in a time-division manner. The liquid crystal display panel sequentially includes: a first substrate, a first alignment film, a liquid crystal layer, a second alignment film, and a second substrate. The first substrate has a plurality of pixel electrodes arranged in a matrix in the row and column directions. The liquid crystal layer is composed of a liquid crystal material containing liquid crystal molecules. When an alignment vector is defined with the long axis end of the liquid crystal molecules on the first substrate side as the starting point and the long axis end of the liquid crystal molecules on the second substrate side as the ending point, when no voltage is applied, the liquid crystal layer has a first domain and a second domain that are different from each other in terms of the alignment vector.

[0023] (2) Furthermore, in one embodiment of the present invention, the liquid crystal display device is configured as described in (1) above, wherein when the first domain and the second domain are viewed from above, the orientation vector of the first domain and the orientation vector of the second domain are parallel to each other.

[0024] (3) Furthermore, in one embodiment of the present invention, based on the configuration of (1) above, when the first domain and the second domain are viewed from above, the endpoint of the liquid crystal molecules contained in the first domain is located closer to the second domain than the starting point of the liquid crystal molecules contained in the first domain, and the endpoint of the liquid crystal molecules contained in the second domain is located closer to the first domain than the starting point of the liquid crystal molecules contained in the second domain.

[0025] (4) Furthermore, one embodiment of the present invention is a liquid crystal display device that performs transparent display of a background based on the configuration of (1), (2) or (3) described above, and is in a normally black mode.

[0026] (5) In addition, in one embodiment of the present invention, the liquid crystal display device is configured as described in (1), (2), (3) or (4) above, wherein the birefringence Δn of the liquid crystal material is 0.12 or above.

[0027] (6) In addition, the liquid crystal display device of one embodiment of the present invention is based on the above (1), (2), (3), (4) or (5) configurations, wherein the rotational viscosity coefficient γ1 of the liquid crystal material is less than 100 mPa·s.

[0028] (7) Furthermore, in one embodiment of the liquid crystal display device of the present invention, based on the configuration described in (1), (2), (3), (4), (5), or (6) above, the RP value of the liquid crystal display panel shown in the following formula (1) is 3.66 or less.

[0029] RP value = (γ1 / K) 33 )×{(d d ) 2 / (d b ) 2}(1)

[0030] In the formula, γ1 represents the rotational viscosity coefficient of the liquid crystal material (mPa·s), and K 33 d represents the bending elasticity coefficient of liquid crystal molecules. d The thickness of the liquid crystal layer is expressed in μm, d b It is 3μm.

[0031] (8) Furthermore, in one embodiment of the present invention, the liquid crystal display device is based on the configuration described in (1), (2), (3), (4), (5), (6) or (7) above, wherein the liquid crystal material comprises a compound having an alkenyl group.

[0032] (9) In a liquid crystal display device according to an embodiment of the present invention, the liquid crystal material comprises a compound having a phenyl group, based on the configuration described in (1), (2), (3), (4), (5), (6), (7), or (8) above.

[0033] (10) Furthermore, in one embodiment of the present invention, the liquid crystal display device is based on the configuration described in (1), (2), (3), (4), (5), (6), (7), (8), or (9) above, wherein the pretilt angle of the liquid crystal molecules is 89° or less.

[0034] (11) Furthermore, in one embodiment of the present invention, the liquid crystal display device is based on the configuration described in (1), (2), (3), (4), (5), (6), (7), (8), (9), or (10) above, wherein the liquid crystal display panel has a drop response property of 2.55 m seconds or less.

[0035] (12) Furthermore, in one embodiment of the present invention, the liquid crystal display device is configured as described in (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), or (12) above, wherein the liquid crystal display panel has a rise response property of 2.75 m seconds or less.

[0036] (13) Furthermore, in one embodiment of the present invention, the liquid crystal display device is configured in accordance with the above (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11) or (12), and each frame period includes a subframe period corresponding to red, blue and green respectively, wherein the frequency of the subframe period is 180 Hz or more.

[0037] (14) Furthermore, in one embodiment of the present invention, the liquid crystal display device is configured based on the above (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12) or (13) above, and during each frame period, the subframe period corresponding to red, green and blue is separated by a black display period corresponding to the period when the light source is turned off, and the subframe period corresponding to red, green and blue respectively includes red, black, blue, black, green and black in sequence.

[0038] (15) Furthermore, in one embodiment of the present invention, based on the configuration described in (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13), or (14), the controller inputs a trigger signal every frame period, and within one frame period, the light source is extinguished from the start of the descent in the optical response waveform at the upper end of the liquid crystal display panel to 1.20 to 2.45 m seconds.

[0039] (16) In one embodiment of the present invention, the liquid crystal display device is configured as described in (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13), (14) or (15) above, wherein the scanning process of the liquid crystal display panel is performed at least twice at 480 to 720 Hz during at least one of the subframes.

[0040] (17) The liquid crystal display device according to one embodiment of the present invention has an NTSC ratio of 90% or more based on the configuration described in (1), (2), (3), (4), (5), (6), (7), (8), (9), (10), (11), (12), (13), (14), (15), or (16) above.

[0041] Beneficial effects

[0042] According to the present invention, a liquid crystal display device is provided that can achieve high-speed response, high transmittance and contrast, and excellent viewing angle characteristics in both rising and falling directions. Attached Figure Description

[0043] Figure 1 The above are response waveform diagrams (a) of the liquid crystal display device of Example 1 and (b) of the liquid crystal display device (Comparative Example 1) using a liquid crystal display panel in TN mode.

[0044] Figure 2A The results show the brightness of a monochrome display on a liquid crystal display device (Comparative Example 1) using a TN mode liquid crystal display panel.

[0045] Figure 2B The results show the brightness of a monochrome display on a liquid crystal display device (Comparative Example 1) using a TN mode liquid crystal display panel.

[0046] Figure 3A The results show the evaluation of the viewing angle characteristics of a liquid crystal display device (Comparative Example 1) using a TN mode liquid crystal display panel.

[0047] Figure 3B The results are the evaluation of the viewing angle characteristics of a liquid crystal display device (Comparative Example 1) using a TN mode liquid crystal display panel.

[0048] Figure 4A This is a schematic diagram of the orientation of liquid crystal molecules when light is transmitted through a portion of the liquid crystal layer in a pixel where the unit thickness is at an intermediate value, in a liquid crystal display device (b) having a liquid crystal display panel with TN mode and displaying color via FSC driving, and a liquid crystal display device (c) having a liquid crystal display panel with 1D-VA mode and displaying color via FSC driving.

[0049] Figure 4B This is a schematic diagram showing the configuration of the TFT wiring for the pixel.

[0050] Figure 4C This is a schematic diagram showing the configuration of BM or light-shielding metal.

[0051] Figure 5 The results of the study on transmittance, color gamut, etc., are for a liquid crystal display device (b) with a liquid crystal display panel in TN mode and a liquid crystal display device (c) with a liquid crystal display panel in 1D-VA mode and a liquid crystal display device (c) with a liquid crystal display panel in 1D-VA mode and a liquid crystal display device (c) with a liquid crystal display panel in 1D-VA mode and a liquid crystal display device (c) with a liquid crystal display panel (c) ...

[0052] Figure 6A This is a diagram used to illustrate the method of analyzing the mixing rate based on the optical response waveform.

[0053] Figure 6B This is a diagram used to illustrate the method of analyzing the mixing rate based on the optical response waveform.

[0054] Figure 6C This is a diagram used to illustrate the method of analyzing the mixing rate based on the optical response waveform.

[0055] Figure 7 This is a diagram used to illustrate the method of analyzing the mixing rate based on the optical response waveform.

[0056] Figure 8 The analysis results are for the liquid crystal display device (a) of Embodiment 1, the liquid crystal display device (b) having a TN mode liquid crystal display panel and performing color display by FSC driving, and the liquid crystal display device (c) having a 1D-VA mode liquid crystal display panel and performing color display by FSC driving.

[0057] Figure 9 The analysis results are for the liquid crystal display device (a) of Embodiment 1, the liquid crystal display device (b) having a TN mode liquid crystal display panel and performing color display by FSC driving, and the liquid crystal display device (c) having a 1D-VA mode liquid crystal display panel and performing color display by FSC driving.

[0058] Figure 10A This is a schematic diagram showing the relationship between the frame period and the lighting time of the light source.

[0059] Figure 10B This diagram is used when studying the relationship between the frame period and the lighting time of the light source.

[0060] Figure 11 This is a timing diagram used to illustrate the FSC driving in the liquid crystal display device of Embodiment 1.

[0061] Figure 12 It is used to illustrate in such Figure 11 The waveform diagram shows the moment when the light source is lit in the driven liquid crystal display device.

[0062] Figure 13 This is a diagram illustrating an example of a system overview of the FSC driver.

[0063] Figure 14 It is aimed at Figure 13 The graph shown illustrates the relationship between the number of scans and brightness of a liquid crystal display panel driven by an FSC, based on a study of the response waveform.

[0064] Figure 15A Is using Figure 13 The diagram shown is of a liquid crystal display panel driven by an FSC, examining the lighting moments when green is displayed.

[0065] Figure 15B Is using Figure 13 The diagram shown is of a liquid crystal display panel driven by an FSC, examining the lighting moments when green is displayed.

[0066] Figure 16 This is a diagram illustrating the measurement method for NTSC in TFT panels.

[0067] Figure 17A This diagram illustrates the NTSC measurement method for objects that do not have a TFT substrate.

[0068] Figure 17B It is the display image when blue (B), green (G), and red (R) are displayed in monochrome when liquid crystal material (c1) (1D-VA mode) is used as the test unit and polyimide is used as a pair of alignment films.

[0069] Figure 17C It shows that it is aimed at Figure 17B The test unit used utilizes Figure 17A The method shown is used to measure NTSC and calculate the NTSC ratio, and the results are presented in a graph.

[0070] Figure 18 This is a cross-sectional schematic diagram showing an example of the liquid crystal display panel of Embodiment 1.

[0071] Figure 19 It is a diagram illustrating the relationship between the tilt orientation of liquid crystal molecules and the orientation vector.

[0072] Figure 20 This is a schematic diagram showing the relationship between the liquid crystal alignment axis and the polarization axis of the liquid crystal display panel in Embodiment 1.

[0073] Figure 21A These are response waveform diagrams of the liquid crystal display device (a) of Embodiment 1, the liquid crystal display device (b) having a TN mode liquid crystal display panel and performing color display with FSC driving, and the liquid crystal display device (c) having a 1D-VA mode liquid crystal display panel and performing color display with FSC driving.

[0074] Figure 21B It means from respectively Figure 21A The response waveforms shown in (b) and (c) are plots of the calculated mixing ratios.

[0075] Figure 22 This is a cross-sectional schematic diagram of a transparent display that uses the liquid crystal display panel of Embodiment 2.

[0076] Figure 23 This is a schematic diagram showing the relationship between the liquid crystal alignment axis and the polarization axis of the liquid crystal display panel in Modified Example 1.

[0077] Figure 24 This is a schematic diagram showing the orientation state of the liquid crystal molecules in the liquid crystal display panel used in Example 1.

[0078] Figure 25 This is a comparison table showing the evaluation results of various physical properties of Examples 1-1 and Comparative Examples 1-1.

[0079] Figure 26A This is a graph showing the results of studying the brightness of monochrome display using the liquid crystal display devices of Examples 1-2.

[0080] Figure 26B This is a graph showing the results of studying the brightness of monochrome display using the liquid crystal display devices of Examples 1-2.

[0081] Figure 27 The evaluation tests on the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3 illustrate the measured angles, polar angles, and azimuth angles.

[0082] Figure 28A This is an evaluation test of the viewing angle characteristics in Examples 1-3, illustrating the orientation of the liquid crystal display panel.

[0083] Figure 28B This is an evaluation test of the viewing angle characteristics in Comparative Examples 1-3, illustrating the orientation of the liquid crystal display panel.

[0084] Figure 29A The original image (1) used in the evaluation tests of the viewing characteristics in Examples 1-3 and Comparative Examples 1-3.

[0085] Figure 29B The original images (2) used in the evaluation tests of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3 are shown.

[0086] Figure 29C The original image (3) used in the evaluation tests of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0087] Figure 29D The original images (4) used in the evaluation tests of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3 are shown.

[0088] Figure 30 These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0089] Figure 31A These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0090] Figure 31B These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0091] Figure 31C These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0092] Figure 31D These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0093] Figure 31E These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0094] Figure 31F These are the evaluation results of the viewing angle characteristics in Examples 1-3 and Comparative Examples 1-3.

[0095] Figure 32A This is the result of confirming the vertical stripe formation when displaying in monochrome in Comparative Example 2.

[0096] Figure 32B This is the result of confirming the vertical stripe formation when displaying in monochrome in Comparative Example 2.

[0097] Figure 32C This is the result of confirming the vertical stripe formation when displaying in monochrome in Comparative Example 2.

[0098] Figure 33 This is a schematic diagram showing the configuration of the liquid crystal display device used in the property measurement in Examples 2-1, 2-2 and 2-3.

[0099] Figure 34 The results of the NTSC ratios measured in Examples 2-1, 2-2, and 2-3 are shown.

[0100] Figure 35 These are the response time measurement results from Examples 2-1 and 2-2.

[0101] Figure 36 This is a conceptual diagram illustrating an example of a method for measuring rotational viscosity coefficient according to JIS Z8803:2011. Detailed Implementation

[0102] The liquid crystal display device according to embodiments of the present invention will now be described. The present invention is not limited to the contents described in the following embodiments, and design changes can be appropriately made within the scope of satisfying the configuration of the present invention.

[0103] (Implementation Method 1)

[0104] The liquid crystal display device of this embodiment performs color display within a frame period that includes multiple subframe periods by field-sequence driving. This liquid crystal display device of the present embodiment includes at least a liquid crystal display panel, a light source, and a controller. The light source illuminates the liquid crystal display panel with light of multiple colors, and the controller drives the light source so that the light of multiple colors illuminates the liquid crystal display panel in a time-division manner.

[0105] The light source, for example, switches and illuminates red (R), green (G), and blue (B) light separately in a time-division manner. For instance, during the R display period of the liquid crystal display panel, only red light is illuminated; during the G display period, only green light is illuminated; and during the B display period, only blue light is illuminated. Thus, the timing of pixel driving in the liquid crystal display panel and the emission timing of each color light from the light source need to be synchronized. Therefore, it is preferable that the controller drives the light source to emit light corresponding to the light emission period of each display color subframe. Specifically, it is preferable that the controller includes control circuitry that synchronizes the R display period, G display period, and B display period of the liquid crystal display panel with the illumination timing of the red light R, green light G, and blue light B from the light source. "Synchronization" generally refers to emitting light of the same color during the same period.

[0106] As a light source, an illumination device having a light source unit and a light guide plate can be used, for example. The light source unit can emit various colors of light, including red light (R), green light (G), and blue light (B). For example, the light source unit includes red LEDs, green LEDs, and blue LEDs. The light guide plate can guide the colored light emitted from the light source unit to the liquid crystal display panel 1. In addition, various illumination elements used in conventional FSC-type display devices can be used as the light source, controller, and limiting circuit.

[0107] Each frame period includes a subframe period corresponding to the color determined by the illuminated state of the light source and a subframe period for displaying black corresponding to the off state of the light source (also called a black display period). Specifically, each frame period preferably includes subframe periods corresponding to red (R), green (G), and blue (B) respectively (also called R display period, G display period, and B display period respectively), and more preferably includes a black display period.

[0108] The subframe periods for each color, illuminated by a light source, are set in a non-repeating manner. For example, at least three subframe periods, including one R display period, one G display period, and one B display period, are set within the period (one frame period) for displaying one full-color image. In this case, in the liquid crystal display panel, the red component image, green component image, and blue component image constituting the full-color image are displayed sequentially and time-divisionally within one frame period.

[0109] Figure 6A , Figure 6B , Figure 6C as well as Figure 7 This is a diagram illustrating a method for analyzing color mixing rate based on optical response waveforms (also known as response waveforms or response waveform diagrams). Through... Figure 7 The signal generator (FG) connected to the control computer (PC) shown inputs a trigger signal to generate a voltage waveform based on the FSC drive (see reference). Figure 6A ).exist Figure 6A In the diagram, the horizontal axis represents time (m seconds), Black indicates the black display state (no voltage applied; OFF), and W indicates the white display state (voltage applied; ON). Let the duration of W be 5.56 m seconds, and the duration of Black be 11.12 m seconds. Figure 6B The upper part shows the response waveform obtained in this way. The response waveform can be used... Figure 7 It was obtained using an oscilloscope as shown. Figure 6B The lower part shows the voltage waveform. The vertical axis of the response waveform is normalized brightness (unit: au: arbitrary unit), and the horizontal axis is time (m seconds). For example... Figure 7 As shown, a photodiode that detects the intensity of light emitted from the TEG (test elementary group) unit via a polarizing plate (not shown) is connected to an oscilloscope. Furthermore, as a backlight (not shown), a continuous light white backlight (trade name "FUJICOLOR Light Box Color Illuminator Pro A4") is preferably used.

[0110] according to Figure 6B The upper part shows the response waveform to calculate the mixing ratio, and it is like... Figure 6C The transformation is shown as grayscale. Specifically, firstly, for example, in... Figure 7 The center of the middle segment of the TEG cell shown Measure the response waveform. Next, imagine the scan time (delay time from the start position) of three specified points (i.e., the start position, the middle position, and the end position) within the channel of an actual liquid crystal display panel (liquid crystal module), and move the waveform in parallel. The voltage is 0V when no voltage is applied (OFF period: black display state) and 7.0V when voltage is applied (ON period: white display state). Using light sources that emit red (R), blue (B), and green (G) light, the lighting order in the FSC driver is set according to R, B, G. Subtract the value of the black portion from each response waveform. In addition, integrate the lighting period of each light source, set the maximum integral value to 100%, and calculate the crosstalk rate of each color during the lighting period. Convert the obtained crosstalk rate into grayscale and assign it to each component of RGB monochrome according to the lighting order of the light sources. Input the display color into the "Color Setting" of any part. Gradually reproduce the display color of each scan position as needed. A 50% duty cycle means setting the illumination time of each light source to half the duration of each subframe.

[0111] In this specification, the rising response refers to the transition from a black display state (dark state) to a white display state (bright state). As described later, the rising response speed can be evaluated based on rising response properties. That is, when the state with a normalized brightness of 10% of the response waveform is defined as the black display state, and the state with a normalized brightness of 90% of the response waveform is defined as the white display state (with the maximum integral value set to 100%), the evaluation can be based on the time of optical change from the black display state to the white display state. Similarly, the falling response refers to the transition from a white display state (bright state) to a black display state (dark state). The falling response speed can be evaluated based on falling response properties as described later. That is, when the state with a normalized brightness of 10% of the response waveform is defined as the black display state, and the state with a normalized brightness of 90% of the response waveform is defined as the white display state (with the maximum integral value set to 100%), the evaluation can be based on the time of optical change from the white display state to the black display state.

[0112] exist Figure 8 and Figure 9 In this study, the color mixing rate was investigated using the aforementioned analytical method. Specifically, the color mixing rate was calculated from the response waveform during ON-OFF-OFF waveform input (monochrome display). This color mixing rate was considered as transmittance, converted to a grayscale value of γ = 2.2, and then analyzed with the light source illumination sequence set to R, B, G (refer to...). Figure 9 (refer to the "R→B→G" column), and when the mixing ratio is set to R, G, B in that order (see...). Figure 9The "R→G→B" columns will be used to reproduce the displayed colors. In this discussion, the brightness information of each color of the light source is not considered.

[0113] The method for calculating the color mixing ratio based on the above response waveform first calculates the luminance integral value L1 when the first light source (BL1) is lit after obtaining the response waveform. Next, it calculates the luminance integral value L2 when the second light source (BL2) is lit after the first light source (BL1) is turned off. Then, it calculates the luminance integral value L3 when the third light source (BL3) is lit after the second light source (BL2) is turned off. L2 is set as the "color mixing ratio (%) of BL2" relative to L1, and L3 is set as the "color mixing ratio (%) of BL3" relative to L1 (see reference). Figure 9 For convenience, L1 relative to L1 is "the mixing rate of BL1 (%)" (i.e., 100.0%).

[0114] exist Figure 8 and Figure 9 In the above, (a) shows the resolution result of the liquid crystal display device of this embodiment. For comparison, the resolution results (b) of a liquid crystal display panel with TN mode and a device for color display driven by FSC are also recorded, as well as the resolution results (c) of a liquid crystal display panel with 1D-VA mode and a device for color display driven by FSC.

[0115] like Figure 9 As shown, in 1D-VA mode (c), the BL2 mixing rate is as high as 38%, and each monochrome color is displayed faintly. Furthermore, in (c), when the light source illumination order is set to R, G, B, the displayed color (input color) cannot be accurately displayed. More specifically, as... Figure 9 As shown in the "R→G→B" column of "Monochrome Display Color," the input color (the color of the light source) is treated as yellow (or orange) when R, and as purple (or bluish-purple) when B. Setting the light source lighting order to R, B, G is better than setting it to R, G, B. However, even then, the display will be lighter and less accurate (see [reference]). Figure 9 (The "R→B→G" column in the "Monochrome Display Color"). In contrast, in the liquid crystal display device (a) and TN mode (b) of this embodiment, the mixing rate of BL2 is 3% and 0.8% respectively, and the reproduction rate of the displayed color is also high, both displaying the displayed color approximately accurately. In addition, there is no difference between (a) and (b) due to the lighting order of the light source.

[0116] The preferred lighting sequence for the light sources is either red (R), blue (B), green (G) or red (R), green (G), blue (B). If we consider the result of (c) above (refer to...), Figure 9If it is considered that lighting up in the order of R, B, G would more accurately display the colors, then it is preferable to set the lighting order to R, B, G from the viewpoint of more accurate color display. Therefore, it is preferable that each frame period includes subframe periods corresponding to red (R), blue (B), and green (G) respectively.

[0117] More preferably, within each frame period, the subframe periods corresponding to red (R), green (G), and blue (B) are separated by a black display period corresponding to the light source's off time, sequentially including red (R), black, blue (B), black, green (G), and black. That is, preferably, one frame period sequentially includes an R display period, a black display period, a B display period, a black display period, a G display period, and a black display period. In this manner, the response speed decreases faster, color mixing is better avoided, and thus monochromatic brightness is further improved. The controller adjusts the on and off times of the red, blue, and green lights to make each frame period conform to this manner.

[0118] Figure 10A as well as Figure 10B This is a schematic diagram illustrating the relationship between frame duration and the illumination time of the light source. An example is shown here when displaying blue. (Example:...) Figure 10A As shown, the liquid crystal display device is driven by inputting a trigger signal (Timing controller) every frame period. In this example, the frequency of each subframe period is 180Hz, and the frequency of one frame period is 60Hz. In the bar chart related to the LC device period, ON indicates the period during which voltage is applied, and OFF indicates the period during which no voltage is applied. In the bar chart related to the LED light source (LED B / L Lighting), Black indicates the period during which the light source is off, B indicates the period during which blue light is on, G indicates the period during which green light is on, and R indicates the period during which red light is on. Figure 10B The schematic diagram shows the sequence of light sources and their on / off times at this point. Figure 10B In the diagram, Black represents the period when the light source is off, B represents the period when the blue light is on, G represents the period when the green light is on, and R represents the period when the red light is on. The illumination time is adjusted according to the brightness (number of LEDs) of the LEDs used in the light source. In monochrome display, this is coordinated with the response waveform. Figure 10A During or before / after the period of y, the illumination time of the light source is adjusted (specifically, the start position of the sequence illumination). Thus, the results of the study on the illumination time of the light source, as described above, confirm that the arrangement of a frame period sequentially including the R display period, black display period, B display period, black display period, and G display period is appropriate.

[0119] The controller preferably adjusts the illumination time of the light source based on the optical response waveform of the liquid crystal display panel. For example, preferably, after inputting a trigger signal every frame, the light source is extinguished within one frame, from the start of the descent in the optical response waveform at the top of the liquid crystal display panel to 1.20–2.45 ms. This "1.20–2.45 ms period in the optical response waveform at the top of the liquid crystal display panel," as described later, is the period during which the color gamut of the middle portion of the liquid crystal display panel is maximized. If the light source is extinguished during this period, a higher color gamut can be achieved, and further, the monochromatic brightness can be improved.

[0120] The frequencies during each subframe period are preferably 180 Hz or higher. This allows for a faster response time. More preferably, they are 180 to 480 Hz. Furthermore, the frequency during each frame period is preferably 50 Hz or higher. More preferably, it is 60 Hz or higher. Particularly preferred is a subframe period that includes an R display period, a G display period, and a B display period, with each frame period having a frequency of 60 Hz or higher. Furthermore, the frequency during each frame period is preferably 120 Hz or lower.

[0121] In at least one subframe period, it is preferable to perform the liquid crystal display panel scanning process at least twice at a frequency of 480 to 720 Hz (i.e., 1.38 to 2.08 ms). This further improves the monochrome brightness. In the liquid crystal display device of this embodiment, by scanning twice at a frequency equivalent to 480 Hz (2.08 ms), the monochrome brightness can reach the maximum grayscale value (255 levels) when using a static driving method.

[0122] Figure 11 This is a timing diagram used to illustrate the FSC drive in the liquid crystal display device of this embodiment. For example... Figure 1 As shown, each frame period includes three sub-frame periods: blue display period Tb, green display period Tg, and red display period Tr. The first half of each sub-frame period (the period before the PWM signal rises) corresponds to the scan processing period (also known as the scan period) Tsc. The illumination time of the light source is set to 2.2ms for blue light, 3.8ms for green light, and 3.3ms for red light, with the illumination sequence set accordingly. The illumination time varies depending on the color to adjust the white balance. The illumination time is adjusted based on the brightness (number of LEDs) of the LEDs used in the light source. PWM stands for Pulse Width Modulation.

[0123] exist Figure 11In this process, the LCD panel is scanned twice at 480Hz (2.08 ms). During one frame, the total scan time for the RGB 3 colors is 12.48 ms (2.08 ms each × 2 times × 3 colors), and the pause period after scan processing within each subframe is 4.20 ms (1.40 ms each × 3 colors). In this case, one frame period is 16.68 ms (approximately 60Hz). During each subframe, a gap can be appropriately inserted between the first scan (1st) and the second scan (2nd). The internal values ​​of the blue display period Tb and the green display period Tg are fixed, and the blanking of the red display period Tr is finely adjusted synchronously with the input. During the green display period, the start of the second scan process overlaps with the green light illumination time.

[0124] The liquid crystal display device of this embodiment includes a TAB (TAPE Automated Bonding) or COF (Chip on Film) as a mounting component.

[0125] In this specification, scanning processing refers to the process of writing liquid crystal signals from the side of the liquid crystal display panel opposite to the side of the TAB or COF where the mounting components are arranged (i.e., the lower end of the liquid crystal display panel) to the side of the TAB or COF where the mounting components are arranged (i.e., the upper end of the liquid crystal display panel).

[0126] Figure 12 It is used to illustrate in such Figure 11 A waveform diagram showing the illumination time of the light source in such a driven liquid crystal display device. Figure 12 In the diagram, the horizontal axis is set to time (m seconds), and the vertical axis is set to the normalized brightness during waveform input (monochrome display). (A) is the response waveform when a trigger signal is input at the start of the scan process (at the start of the scan or on the side of the LCD panel opposite to the TAB or COF). (B) is the response waveform when a trigger signal is input 1.04m seconds after the start of the scan process (at the center of the scan or in the middle of the LCD panel). (C) is the response waveform when a trigger signal is input 2.08m seconds after the start of the scan process (at the end of the scan or on the side of the TAB or COF of the LCD panel).

[0127] Figure 12 The response waveforms (A), (B), and (C) are respectively, with (C) being the waveform of a 1D mode liquid crystal display panel using one liquid crystal alignment axis. (B) is the waveform of a TN mode liquid crystal display panel.

[0128] according to Figure 12The response waveforms (b) and (c) show how the illumination time of the light source is adjusted. For example, if it is green light, the green light source is turned off at time X, and scanning processing during the red display period begins simultaneously. In this case, the illumination time of the green light can be adjusted by making the illumination time within the range of X to Y. Furthermore, the illumination time of the light source can also be adjusted in the same way in the liquid crystal display device of this embodiment.

[0129] Figure 13 This is a diagram illustrating an example of a system overview for FSC driving. In this example, the frame period is set to 60Hz, the subframe period to 180Hz, and the scanning processing period (scanning period) of the liquid crystal display panel is set to 480Hz. Furthermore, the light source illumination sequence is set to B, R, G. Figure 13 In the image, the slanted arrow (bottom right arrow) indicates the output delay of 1 frame to the LCD panel and backlight relative to the Tcon input.

[0130] Figure 14 Based on response waveform Figure 13 The graph shown illustrates the relationship between the number of scans and brightness in an FSC-driven liquid crystal display panel. Figure 14 In this model, one frame lasts 16.6 m seconds, and each subframe lasts 5.5 m seconds. The vertical axis represents the grayscale levels (also known as grayscale levels), and the "255 level" line represents the maximum grayscale value (255 levels) when using the static driving method.

[0131] like Figure 14 As shown, the scanning process cannot reach 255 levels in a single scan. When using the FSC driving method, it is believed that in the liquid crystal layer of a liquid crystal display panel (e.g., a TFT panel), in the longitudinal electric field along the cell thickness direction, CV characteristics (also known as capacitance-voltage dependence) are exhibited, depending on the liquid crystal orientation. However, if two scans are performed, 255 levels can be achieved. It is believed that the CV characteristics are improved by performing multiple scans. Furthermore, by further increasing the auxiliary capacitance of the liquid crystal display panel, the capacitance-voltage dependence of the liquid crystal material can also be improved, but in this case, a trade-off must be made with the aperture ratio.

[0132] Figure 15A and Figure 15B It is for use Figure 13 The graph shown illustrates the study of the illumination time when a green color is displayed on a liquid crystal display panel based on FSC driving. Figure 15A and Figure 15B In this context, each subframe lasts for 5.52 milliseconds. Figure 15AIn the diagram, (A) is the response waveform of the upper part (i.e., the viewing side) of the liquid crystal display panel, (B) is the response waveform of the middle part of the liquid crystal display panel, and (C) is the response waveform of the lower part (i.e., the back side) of the liquid crystal display panel. When displaying green, a small amount of blue is mixed in the upper part of the liquid crystal display panel (x portion of (A)), a small amount of red is mixed in the lower part of the liquid crystal display panel (z portion of (C)), and color mixing is almost impossible to detect in the middle part of the liquid crystal display panel (y portion of (B)). The measured NTSC ratio in (A) is 79%, the maximum NTSC ratio in (B) is 93%, and the measured NTSC ratio in (C) is 84%.

[0133] Figure 15B This is a graph showing the NTSC ratio (%) of the middle section of the liquid crystal display panel when the green light source illumination time is set to 0 (m seconds) and the extinguishing time is set to the horizontal axis (m seconds). The NTSC ratio of the middle section being 90% or higher occurs during the period of 1.20 to 2.45 m seconds from the start of the drop in the response waveform at the top (upper end) of the liquid crystal display panel (the period "1.74 ms" in Figure 15). In other words, this period represents the period of maximum color gamut in the middle section of the liquid crystal display panel. The middle section of the liquid crystal display panel is where the observer's gaze is most easily focused. If the green light source is extinguished within the aforementioned period, a higher color gamut can be achieved, and further improvements in monochromatic brightness can be made.

[0134] The liquid crystal display device of this embodiment preferably has an NTSC ratio of 90% or more. More preferably, it has an NTSC ratio of 91% or more, and even more preferably, it has an NTSC ratio of 92% or more. Particularly preferred is that the NTSC ratio of the middle portion of the liquid crystal display panel is 90% or more. More preferably, it has an NTSC ratio of 91% or more, and even more preferably, it has an NTSC ratio of 92% or more.

[0135] Figure 16 This diagram illustrates the method for measuring the NTSC spectrum of a TFT panel. The TFT panel referred to here is a liquid crystal display panel having a TFT substrate as the first substrate. However, if the liquid crystal display panel already has a polarizing plate, this method is not used. Figure 16 The polarizing plate shown.

[0136] In this specification, the NTSC ratio of the liquid crystal display device and the NTSC ratio of the liquid crystal display panel can be determined by... Figure 16 The method shown is used to obtain it.

[0137] like Figure 16As shown, when measuring the NTSC of a TFT panel, the TFT panel (test panel) 420 to be measured is prepared to be sandwiched between a pair of polarizing plates 410 on a substrate. An on-off-off display system in the FSC driver is used. First, a trigger signal is input to the control computer (…). <1> ), input the panel input signal to the test panel ( <2> Next, the FSC driver drives the light source 430, causing the RGB colors to be illuminated in a time-division manner. <3> The luminance (cd / m²) was measured using a spectroradiometer 400 from the opposite side of the light source 430. 2 As a spectroradiometer, for example, the "SR-ULIR" manufactured by Irie Corporation can be used. (The above...) Figure 15B pass Figure 16 The method shown measures NTSC and determines the NTSC ratio.

[0138] Figure 17 is a diagram illustrating the NTSC measurement method for an object without a TFT substrate. This method is useful for selecting liquid crystal materials because it allows measurement of the NTSC of the liquid crystal layer (liquid crystal material).

[0139] like Figure 17A As shown, the liquid crystal material (test unit) 440 to be measured is prepared to be sandwiched between a pair of polarizing plates 410. Alternatively, the test unit can be prepared by clamping it with a pair of alignment films and then further clamped with a pair of polarizing plates. An on-off display system using an FSC driver is employed. First, a trigger signal is input via FG (signal generator). <1> To generate the waveform of the LC voltage driven by the FSC. <2> Then, via the FSC driver, the light source 430 is driven so that the RGB colors are illuminated in a time-division manner. <3> The luminance (cd / m²) was measured using a spectroradiometer 400 from the opposite side of the light source 430. 2 As a spectroradiometer, for example, the "SR-ULIR" manufactured by Irie Corporation can be used.

[0140] As a test unit, using liquid crystal materials (c1) with various physical properties listed in Tables 1 and 2 (1D-VA mode) and polyimide as a pair of alignment films (VA photoalignment films), the blue (B), green (G), and red (R) colors were as follows: Figure 17B That's how it's displayed (monochrome). For this test unit, use... Figure 17A The method shown measures NTSC, and the result of calculating the NTSC ratio is presented in the table below. Figure 17C The smaller the rotation of the triangle, the smaller the color mixing rate, and the lower the NTSC ratio ( Figure 17C The larger the "NTSC" line (as shown in the image), the larger the value.

[0141] The liquid crystal display device of this embodiment performs color display via FSC driving, thus eliminating the need for a color filter. Therefore, the liquid crystal display device of this embodiment does not have a color filter. That is, the liquid crystal display panel of the liquid crystal display device of this embodiment does not have color pixels such as R sub-pixels for displaying red components, G sub-pixels for displaying green components, and B sub-pixels for displaying blue components, as is the case with liquid crystal display panels using color filters. Each pixel of the liquid crystal display panel 1 functions as an individual pixel for full-color display.

[0142] Figure 18 This is a cross-sectional schematic diagram showing an example of the liquid crystal display panel 1 included in the liquid crystal display device of this embodiment. Figure 18 As shown, the liquid crystal display panel 1 of this embodiment sequentially includes a first substrate 100, a first alignment film 21, a liquid crystal layer 200 made of a liquid crystal material containing liquid crystal molecules 210, a second alignment film 22, and a second substrate 300, preferably sequentially provided from the back side to the viewing surface side.

[0143] In this manual, the term "viewing side" refers to the side closer to the screen (display surface) of the liquid crystal display device, and the term "back side" refers to the side farther from the screen (display surface) of the liquid crystal display device.

[0144] The first substrate 100 has an insulating substrate 110 and a plurality of pixel electrodes 120 arranged in a matrix in the row and column directions. The second substrate 300 has an insulating substrate 310 and a common electrode 320.

[0145] The orientation switching of the liquid crystal molecules 210 is achieved by applying voltage to the liquid crystal layer 200 using multiple pixel electrodes 120 and a common electrode 320. In a voltage-free state where no voltage is applied between the pixel electrodes 120 and the common electrode 320, the initial orientation of the liquid crystal molecules 210 is constrained using a first alignment film 21 and a second alignment film 22. Furthermore, the voltage-free state where no voltage is applied between the pixel electrodes 120 and the common electrode 320 includes both a state where no voltage is substantially applied between the pixel electrodes 120 and the common electrode 320 and a state where the applied voltage to the liquid crystal layer 200 is less than a threshold value.

[0146] Even when no voltage is applied, the liquid crystal molecules 210 can be oriented substantially horizontally relative to the main surfaces of the first substrate 100 and the second substrate 300, but are preferably oriented substantially vertically. Hereinafter, this embodiment will be described using the case of substantially vertical orientation as an example.

[0147] Here, "oriented substantially perpendicularly to the main surfaces of the first substrate 100 and the second substrate 300" means that the pretilt angle of the liquid crystal molecules 210 relative to the main surfaces of the first substrate 100 and the second substrate 300 is 75° or more and less than 90°. Conversely, "oriented substantially horizontally relative to the main surfaces of the first substrate 100 and the second substrate 300" means that the pretilt angle of the liquid crystal molecules 210 relative to the main surfaces of the first substrate 100 and the second substrate 300 is 0° or more and less than 15°.

[0148] Furthermore, the pretilt angle of liquid crystal molecules refers to the angle at which the long axis of the liquid crystal molecules is tilted relative to the main surface of each substrate when no voltage is applied to the liquid crystal layer. The main surface of the substrate refers to the substrate surface. Additionally, the polarization axis can be either the absorption axis of the liquid crystal display panel or the transmission axis of the polarizer further included therein.

[0149] When a voltage is applied between the pixel electrode 120 and the common electrode 320, a longitudinal electric field is generated in the liquid crystal layer 200, and the liquid crystal molecules 210 maintain their tilted orientation from the state without applied voltage, and further tilt and align significantly.

[0150] In this specification, the tilt orientation of the liquid crystal molecules 210 is described using an orientation vector that, when viewed from above the liquid crystal display panel 1, originates from the long axis end of the liquid crystal molecules 210 on the first substrate 100 side (also called the tail of the liquid crystal pointer) 210S and ends at the long axis end on the second substrate 300 side (also called the head of the liquid crystal pointer) 210T. The orientation vector is in the same direction as the tilt orientation of the liquid crystal molecules 210 on the first substrate 100 side relative to the first alignment film 21, and in the opposite direction to the tilt orientation of the liquid crystal molecules 210 on the second substrate 300 side relative to the second alignment film 22. In this specification, "orientation" refers to the orientation when projected onto the substrate surface, without considering the tilt angle (polar angle, pretilt angle) from the normal direction of the substrate surface. Furthermore, when the liquid crystal molecules 210 are substantially vertically oriented (slightly tilted) in the unapplied voltage state, since they maintain the tilted orientation of the unapplied voltage state and are tilted more significantly when a voltage is applied, the starting point 210S and the ending point 210T of the orientation vector can be confirmed simply by applying a voltage to the liquid crystal layer 200.

[0151] In the liquid crystal display panel 1 of this embodiment, a plurality of pixels are arranged in a matrix in both the row and column directions. The row and column directions intersect. Preferably, the row direction is orthogonal to the column direction. More preferably, the row direction is aligned with the horizontal direction of the display area displaying the image, and the column direction is aligned with the vertical direction of the display area.

[0152] In the liquid crystal layer 200, first domains and second domains with different orientation vectors are provided in each region overlapping with multiple pixel electrodes. That is, each pixel has a region (domain) in which two or more liquid crystal molecules are arranged along a certain orientation direction. As a driving method for the domains, examples include a vertical orientation (longitudinal electric field) mode in which the liquid crystal molecules are oriented perpendicularly (approximately perpendicularly) to the main surface of the substrate when no voltage is applied, and a horizontal orientation (transverse electric field) mode in which the liquid crystal molecules are oriented horizontally to the main surface of the substrate when no voltage is applied. Among these, the vertical orientation mode is preferred at points where blurring of the transmitted image can be sufficiently suppressed. In the vertical orientation mode, it is preferable that when the first domain and the second domain are viewed from above, the orientation vectors of the first domain and the second domain are parallel to each other (also called the 2D-ECB parallel orientation mode). Furthermore, when viewed from above, it is preferable that the endpoints of the liquid crystal molecules contained in the first domain are located further into the second domain than the origins of the liquid crystal molecules contained in the first domain, and that the endpoints of the liquid crystal molecules contained in the second domain are located further into the first domain than the origins of the liquid crystal molecules contained in the second domain (also known as 2D-ECB mountain-shaped alignment mode). "2D-ECB" is an abbreviation for "2 Domain Electrically Controlled Birefringene".

[0153] Of the two methods described above, in the former, the 2D-ECB parallel alignment mode liquid crystal display panel, the liquid crystal alignment axis is uniform in both the horizontal and vertical directions, effectively suppressing periodic variations in the liquid crystal alignment axis, thus further suppressing blurring of the transmitted image. Furthermore, it also achieves excellent viewing angle characteristics with symmetrical left and right viewing angles. Therefore, the 2D-ECB parallel alignment mode is more preferred. Additionally, since the 2D-ECB parallel alignment mode liquid crystal display panel is a normally black mode, it can further improve contrast.

[0154] Figure 19 This is a diagram illustrating the relationship between the tilt orientation of liquid crystal molecules and the orientation vector. To easily understand the tilt orientation of liquid crystal molecules 210, a pin (cone) is used to represent liquid crystal molecules 210, with the base of the cone representing the second substrate 300 side (observer side) and the apex of the cone representing the first substrate 100 side.

[0155] The first alignment film 21 and the second alignment film 22 are aligned in a column direction with first domain 1Pa and second domain 1Pb having different alignment vectors 210V. This method achieves good viewing angle characteristics. Specifically, the first alignment film 21 and the second alignment film 22 are aligned in the column direction within each pixel 1P that overlaps with the single pixel electrode 120 with first domain 1Pa and second domain 1Pb having different alignment vectors 210V.

[0156] Figure 20 This is a schematic diagram illustrating the relationship between the liquid crystal alignment axis and the polarization axis when the liquid crystal display panel of this embodiment is in a 2D-ECB parallel alignment mode. Within a pixel 1P, a first domain 1Pa and a second domain 1Pb with different alignment vectors are arranged side by side in the column direction. These domains can be formed by making the alignment processes of the first alignment film 21 and the second alignment film 22 different. Under the applied voltage, the liquid crystal molecules 210 are tilted and aligned in a manner consistent with the alignment vectors of each of the multiple domains. Furthermore, the alignment vector of each domain can be determined by the orientation of the liquid crystal molecule 210 located in the middle of the domain when viewed from above and in the middle of the liquid crystal layer 200 when viewed in cross-section.

[0157] like Figure 20 As shown, when viewed from above, the liquid crystal alignment axes 210Xa and 210Xb of the first domain 1Pa and the second domain 1Pb are obliquely intersecting with respect to the polarization axes 10Xa of the first polarizing plate 11 and 10Xb of the second polarizing plate 12, and are parallel to each other. By arranging them in this way, the liquid crystal alignment axes 210Xa and 210Xb of the first domain 1Pa and the second domain 1Pb intersect with respect to the polarization axis 10Xa of the first polarizing plate 11 at the same azimuth angle, and with respect to the polarization axis 10Xb of the second polarizing plate 12 at the same azimuth angle. As a result, in each pixel 1P, the periodic variation of the azimuth angles of the liquid crystal alignment axes 210Xa and 210Xb with respect to the polarization axes 10Xa and 10Xb of each polarizing plate 11 and 12 can be suppressed, thereby suppressing blurring of the transmitted image.

[0158] In this specification, "obliquely intersecting" of two axes (directions) means that the angle (absolute value) between them is greater than 3° and less than 87°, preferably 15° or more and less than 75°, more preferably 25° or more and less than 65°, and particularly preferably 35° or more and less than 55°. Furthermore, in this specification, "mutually parallel" of two axes (directions) means that the angle (absolute value) between them 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). Furthermore, in this specification, "mutually orthogonal" of two axes (directions) means that the angle (absolute value) between them is greater than 87° and less than 90°, preferably greater than 89° and less than 90°, more preferably greater than 89.5° and less than 90°, and particularly preferably 90° (completely orthogonal). When the angle between two axes (directions) is not 90°, it refers to the angle on the acute angle side.

[0159] like Figure 20As shown, the liquid crystal alignment axis 210Xa of the first domain 1Pb and the liquid crystal alignment axis 210Xb of the second domain 1Pb are arranged parallel to the row direction. By adopting this arrangement, excellent viewing angle characteristics with left-right viewing angle symmetry can be achieved.

[0160] The above uses Figure 19 and Figure 20 In this embodiment, when the liquid crystal display panel is in a 2D-ECB parallel alignment mode, the liquid crystal alignment axis 210Xa of the first domain 1Pb and the liquid crystal alignment axis 210Xb of the second domain 1Pb are arranged parallel to each other with respect to the row direction. However, it is also possible to arrange the liquid crystal alignment axis 210Xa of the first domain 1Pb and the liquid crystal alignment axis 210Xb of the second domain 1Pb at an angle with respect to the row direction. By adopting this method, it is possible to arrange the polarization axis of one of the first polarizing plate 11 and the second polarizing plate 12 parallel to the row direction and the polarization axis of the other parallel to the column direction. Therefore, compared with polarizing plates where the polarization axis is arranged at an angle with respect to both the row and column directions, it is possible to reduce waste during the cutting of large polarizing plates and reduce the cost of the liquid crystal display panel.

[0161] In this embodiment, the liquid crystal display panel 1 achieves excellent viewing angle characteristics by using pixels comprising multiple domains. However, when using pixels comprising multiple domains, regions of discontinuous orientation of liquid crystal molecules 210 sometimes occur at the boundaries of adjacent domains. In such regions, since the liquid crystal molecules 210 cannot be oriented in the desired direction, sufficient light cannot be transmitted during display, resulting in what is perceived as a dark area. These linear dark areas are called dark lines. If dark lines occur, the brightness of the pixels decreases, thus reducing the light utilization efficiency of the liquid crystal display panel. The position and size of these dark lines can easily vary depending on each pixel. Therefore, dark lines cause non-uniform optical characteristics in each pixel, resulting in reduced uniformity of display when viewed across the entire surface of the liquid crystal display panel. The deviation in the generation of dark lines is caused by the relationship between the orientation of the boundary portions of adjacent domains and the orientation of adjacent domains. Such deviations in the generation of dark lines can be prevented by providing a structure for positioning (fixing) the dark lines. For example, in the pixel electrode 120, by setting a slit at the boundary between the first domain 1Pa and the second domain 1Pb, the shape of the dark line can be stabilized.

[0162] That is, it is preferable to provide a slit at the boundary between the first domain 1Pa and the second domain 1Pb of the pixel electrode 120. Specifically, the slit is preferably wider than 0 μm and less than 4.5 μm. By providing the slit, an electric field deformation caused by the slit is generated near the boundary between the first domain 1Pa and the second domain 1Pb. As a result, the continuous orientation change at the boundary between the first domain 1Pa and the second domain 1Pb is intentionally suppressed to below 90° to fix the dark lines, thereby improving the brightness of the dark line area.

[0163] Furthermore, it is preferable to provide a light-shielding body at the boundary between the first domain 1Pa and the second domain 1Pb. Since the liquid crystal orientation changes continuously at the boundary between the first domain 1Pa and the second domain 1Pb, there is a possibility that the liquid crystal alignment axis 210Xa of the first domain 1Pa and the liquid crystal alignment axis 210Xb of the second domain 1Pb are not parallel, resulting in dark lines. However, by providing a light-shielding body at the boundary between the first domain 1Pa and the second domain 1Pb, this dark line portion can be blocked, further suppressing blurring. For example, a black matrix can be used as a light-shielding body.

[0164] Next, the liquid crystal display panel 1 will be further described.

[0165] The first substrate 100 may, for example, be a thin-film transistor (TFT) substrate. As a TFT substrate, substrates commonly used in the field of liquid crystal display panels can be used. The TFT substrate has an insulating substrate and includes, in the display area: a plurality of gate lines extending parallel to each other in the row direction on the insulating substrate; and a plurality of source lines extending parallel to each other in a direction intersecting the gate lines (along the column direction) through an insulating film. The plurality of gate lines and the plurality of source lines are integrally formed into a grid to divide each pixel. Thin-film transistors serving as switching elements are disposed at the intersections of each source line and each gate line.

[0166] The second substrate 300 has a common electrode 320. The common electrode 320 is configured to face the pixel electrode 120 across the liquid crystal layer 200. A longitudinal electric field is formed between the common electrode 320 and the pixel electrode 120, and by tilting the liquid crystal molecules 210, a display can be performed.

[0167] The pixel electrode 120 and the common electrode 320 can also be transparent electrodes, for example, formed of transparent conductive materials such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), tin oxide (SnO), or alloys thereof.

[0168] The liquid crystal layer 200 contains liquid crystal molecules 210 that are substantially vertically oriented relative to the main surfaces of the first substrate 100 and the second substrate 300 when no voltage is applied. The orientation of the liquid crystal molecules 210 changes according to the electric field generated in the liquid crystal layer 200 due to the voltage applied between the pixel electrode 120 and the common electrode 320, thereby controlling the amount of light transmitted.

[0169] The liquid crystal layer 200 is composed of a liquid crystal material containing liquid crystal molecules 210.

[0170] Liquid crystal molecule 210 is composed of the following formula:

[0171] Δε = (dielectric constant along the major axis) - (dielectric constant along the minor axis)

[0172] The defined dielectric anisotropy (Δε) can be positive or negative, but in this embodiment, which contains liquid crystal molecules 210 that are substantially perpendicular to the main surfaces of the first substrate 100 and the second substrate 300 when no voltage is applied, the liquid crystal molecules 210 preferably have a negative value. Furthermore, 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. Additionally, the direction of the long axis of the liquid crystal molecules is called the direction of the slow axis.

[0173] The pretilt angle of the liquid crystal molecule 210 is preferably 89° or less. In this case, the rise response can be accelerated, and the monochromatic brightness can be further improved. In addition, dark lines sometimes occur between the first and second domains with different orientation vectors, but if the pretilt angle of the liquid crystal molecule 210 is within the above range, the orientation restraint force of the liquid crystal molecule 210 near the first and second substrates is increased, the liquid crystal orientation axes of the liquid crystal molecules are more easily aligned, and the dark lines can be narrowed. As a result, the transmittance can also be improved. More preferably, it is 88.5° or less, further preferably 88° or less, and particularly preferably 87.5° or less. In addition, considering the trade-off between mode efficiency and black brightness and contrast, it is preferably 85° or more. More preferably, it is 86° or more, and further preferably 87° or more.

[0174] The birefringence Δn of the liquid crystal material is preferably 0.12 or higher. This enables high-speed response and also allows for higher transmittance. More preferably, it is 0.122 or higher, and even more preferably 0.124 or higher. Furthermore, from the viewpoint of further improving contrast, the birefringence Δn is preferably 0.2 or lower, more preferably 0.18 or lower, and even more preferably 0.14 or lower. Most preferably, it is 0.1246 to 0.1399, at which point both transmittance and contrast are further improved.

[0175] Here, the retardation (phase difference) of the liquid crystal layer with the desired transmittance can be obtained as follows: From the perspective of responsive physical properties, a smaller unit thickness (the thickness of the liquid crystal layer) is preferred. However, with a small unit thickness, liquid crystal properties such as a large birefringence Δn and a large dielectric anisotropy Δε are necessary, and there are limitations in the trade-offs between these liquid crystal properties and other properties. Furthermore, with a small unit thickness, there are concerns about reduced yield due to leakage in the vertical direction. However, considering the reduction in the amount of liquid crystal material used, a smaller unit thickness is preferred. Taking these factors into account, the liquid crystal material and unit thickness are preferably selected. Additionally, the thickness (unit thickness) of the liquid crystal layer 200 is preferably... When the birefringence Δn of the liquid crystal material is 0.2, the unit thickness is preferably 1.65 to 1.7 μm; when Δn is 0.18, the unit thickness is preferably 1.83 to 1.89 μm.

[0176] As described above, by increasing the birefringence Δn, specifically by making Δn 0.12 or higher, the cell thickness can be reduced while maintaining a constant delay in the liquid crystal layer. The response speed of liquid crystal molecules is inversely proportional to the square of the cell thickness; therefore, by increasing the birefringence Δn, the response speed can be effectively reduced (i.e., increased). Furthermore, the upper limit of the birefringence Δn is preferably set considering temperature dependence and yield reduction caused by foreign matter. Specifically, it is preferable to set it within the aforementioned range. Thus, in this invention, high-speed response can be achieved without compromising productivity or temperature characteristics.

[0177] The liquid crystal material preferably has a rotational viscosity coefficient γ1 of less than 100 mPa·s. This allows for a faster descent response, enabling a wider color gamut. Furthermore, it also allows for a faster ascent response, further improving monochromatic brightness. More preferably, it is 90 mPa·s or less, even more preferably 80 mPa·s or less, particularly preferably 75 mPa·s or less, and even more preferably 73 mPa·s or less. The rotational viscosity coefficient γ1 is preferably 50 mPa·s or more, more preferably 60 mPa·s or more, and even more preferably 70 mPa·s or more. Most preferably, it is 70 to 73 mPa·s.

[0178] In this specification, the rotational viscosity coefficient γ1 can be determined, for example, using a rotational viscometer according to JIS Z8803:2011 (Methods for measuring the viscosity of liquids). Furthermore, the viscosity coefficient can also be determined using the rotational coefficient, etc., through the transient current method obtained by analyzing the transient current characteristics of parallel alignment units (MASAHIRO IMAI, Mol.Cryst.Liq.Cryst., Vol.262, 267 (1995)), the relaxation method obtained based on the optical response characteristics of parallel alignment units (Shin-Tson, Wu and Chiung-Sheng Wu, Phys.Rev.A42, 2219 (1990)), and the rotating magnetic field method, which calculates γ1 by measuring the torque acting on the liquid crystal in a configuration where a rotating magnetic field can be applied to a cylindrical liquid crystal (V.Tvetokv, Acta Physicochim (USSR), 10, 557 (1939)). However, in this invention, according to JIS Z803:2011, it is preferable to use a method that calculates the viscosity using a rotational viscometer, and the value (rotational viscosity coefficient γ1) obtained by this method is preferably within the above-mentioned preferred range.

[0179] Regarding the measurement method used in JIS Z8803:2011, the measurement was performed as follows.

[0180] First, such as Figure 36 As shown, a certain amount of sample 6 is collected in the sample cup, and the measurement is performed using a device equipped with a rotor 5 and a constant temperature chamber or constant temperature bath 7 while maintaining a certain temperature. The conical-plate rotational viscometer causes the sample, which fills the space between a flat circular plate with the same axis of rotation and a cone with a large apex angle, to rotate in a laminar flow state. The torque or angular velocity is measured by the method described in (a) or (b) below, and the viscosity is calculated by the following formula (4).

[0181] (a) Measure the torque acting on the surfaces of the other circular plates or cones when any one of the flat circular plates or cones is rotated at a certain angular velocity.

[0182] (b) Measure the angular velocity of the plate or cone when either of them is rotated with a certain torque.

[0183] γ1=100×(3α / 2πR 3 )×(M / Ω) (4)

[0184] In the formula, γ1 represents the rotational viscosity coefficient of the liquid crystal material (mPa·s). α represents the angle between the flat circular plate and the cone (rad). π is pi. R represents the radius of the flat circular plate (cm). M represents the torque acting on the flat circular plate or the conical surface (10). -7 N·m).

[0185] Furthermore, if the structure and dimensions of the conical-plate rotational viscometer are determined, then Kc, as shown in equation (5) below, is a constant value:

[0186] 100×(3α / 2πR 3 )=Kc (5)

[0187] (where Kc represents the device constant (rad / cm)) 3 Therefore, equation (4) above can be replaced by equation (6) below;

[0188] γ1=Kc×(M / Ω)(6)

[0189] (The symbols in the formula are the same as those in formula (4) or (5) above). Therefore, by experimentally determining Kc using a standard solution with a known viscosity, it is possible to measure the torque according to method (a) above, or measure the angular velocity according to method (b) above, and thus determine the rotational viscosity coefficient of any sample.

[0190] Here, when the birefringence Δn of the liquid crystal material is 0.12 or higher and the rotational viscosity γ1 is less than 100 mPa·s, it can maintain high-speed response and high transmittance at a higher level, and become a highly reliable and stable liquid crystal material. The preferred ranges for each numerical range are as described above.

[0191] The liquid crystal material preferably contains an alkenyl group. By including an alkenyl group in the liquid crystal material, the rotational viscosity coefficient γ1 can be easily controlled within the aforementioned preferred range.

[0192] Furthermore, the liquid crystal molecule 210 can be a compound with an alkenyl group, and other components besides the liquid crystal molecule can also be compounds with an alkenyl group. The liquid crystal molecule 210 can also contain compounds with an alkenyl group, and may also contain other compounds with an alkenyl group.

[0193] The content of the alkenyl compound relative to the total amount of the liquid crystal material (i.e., the total amount of the liquid crystal layer) is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 52% by weight or more, and particularly preferably 55% by weight or more.

[0194] The alkenyl group may be present in one or more molecules. The number of carbon atoms in the alkenyl group is preferably 1 to 10. More preferably... Compounds containing an alkenyl group are generally preferred for use as alkenyl-based liquid crystals, dienyl-based liquid crystals, diphenylacetylene-based liquid crystals, azazine-based liquid crystals, etc. Specifically, compounds with the following chemical formulas are preferred, for example. The compound shown, the chemical formula below The compounds shown, etc. One or more alkenyl groups may be used.

[0195] [Chemistry 1]

[0196]

[0197] [Chemistry 2]

[0198]

[0199] In the above formula, R 1 and R 2 "Same or different" indicates an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms. Wherein, R... 1 and R 2 All of these represent alkenyl groups with 2 to 5 carbon atoms.

[0200] The liquid crystal material preferably further comprises a compound having phenyl groups. By including a compound having phenyl groups in the liquid crystal material, the birefringence Δn can be easily controlled within the aforementioned preferred range. More preferably, as described later, it comprises a compound having two or more phenyl groups per molecule.

[0201] Furthermore, the liquid crystal molecule 210 can be a compound containing phenyl groups, and other components besides the liquid crystal molecule can also be compounds containing phenyl groups. The liquid crystal molecule 210 can also contain compounds containing phenyl groups, and other compounds containing phenyl groups as well. Additionally, the liquid crystal molecule 210 can be a compound containing both alkenyl and phenyl groups, and other components besides the liquid crystal molecule can be compounds containing both alkenyl and phenyl groups.

[0202] The content of compounds having two or more phenyl groups is preferably 40% by weight or more relative to the total amount of liquid crystal material (i.e., the total amount of liquid crystal layer) per 100% by weight. More preferably, it is 45% by weight or more, even more preferably 47% by weight or more, and particularly preferably 61% by weight or more.

[0203] Preferably, the molecule contains two or more phenyl groups. Biphenyl and terphenyl groups are preferred. That is, the liquid crystal material preferably contains a compound containing biphenyl or terphenyl groups. Examples of compounds containing phenyl groups are compounds shown in chemical formulas (3-1) to (3-11) and compounds shown in chemical formulas (4-1) to (4-36). One or more compounds containing phenyl groups may be used.

[0204] [Chemistry 3]

[0205]

[0206] In the above formula, R 3 The term represents an alkyl group having 1 to 5 carbon atoms or an alkenyl group having 2 to 5 carbon atoms. Preferably, the term refers to an alkyl group having 1 to 5 carbon atoms. R3 With R 4 They can be the same or different.

[0207] R 4 The term refers to an alkyl group having 1 to 5 carbon atoms, an alkoxy group having 1 to 5 carbon atoms, an alkenyl group having 2 to 5 carbon atoms, or an alkenyloxy group having 2 to 5 carbon atoms. Preferably, the term refers to an alkyl group having 1 to 5 carbon atoms or an alkoxy group having 1 to 5 carbon atoms.

[0208] R 5 and R 6 Same or different, indicating alkyl with 1 to 10 carbon atoms or alkenyl with 2 to 10 carbon atoms. R 5 and R 6 One or more methylene groups (-CH2-) present in R can be replaced by O-. Furthermore, R 5 and R 6 One or more hydrogen atoms (H) present in the sample can also be replaced by fluorine atoms (F).

[0209] R 7 and R 8 Same or different, indicating alkyl with 1 to 5 carbon atoms or alkenyl with 2 to 5 carbon atoms. R 7 and R 8 One or more hydrogen atoms (H) present in R can also be replaced by fluorine atoms (F). 9 and R 10 Whether the groups are the same or different, they represent hydrogen atoms (H), alkyl groups with 1 to 18 carbon atoms, or alkenyl groups with 2 to 18 carbon atoms. When alkyl or alkenyl groups are used, it is preferable that the group is not substituted. R 9 and R 10 One or more methylene groups (-CH2-) present in the substance can be substituted by at least one group selected from -O-, -S- and -C≡C-.

[0210] R 11 and R 12 The same or different indicates an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an alkenyl group having 2 to 6 carbon atoms.

[0211] [Chemistry 4]

[0212]

[0213] [Chemistry 5]

[0214]

[0215] [Chemistry 6]

[0216]

[0217] [Chemistry 7]

[0218]

[0219] Figure 21 shows a response waveform diagram (a) of the liquid crystal display device according to this embodiment. Here, the liquid crystal material constituting the liquid crystal layer of the liquid crystal display panel is a liquid crystal material with properties listed in Table 1 (a). For comparison, response waveform diagrams (b) of a device using a TN mode liquid crystal display panel and (c) of a device using a 1D-VA mode liquid crystal display panel are also shown. In the 1D-VA mode liquid crystal layer, a liquid crystal material with properties listed in Tables 1 and 2 (c3) is used.

[0220] Figure 21A The response waveform diagram shown This is a waveform diagram of a red (R) monochrome display when an LED light source emitting RGB light, driven by an FSC, is lit in the order of R (BL1), G (BL2), and B (BL3). Normally, in R monochrome display, light passes through (opens) the liquid crystal layer when the red light R is lit, and is blocked (turned off) when it is not lit. However, in the 1D-VA mode liquid crystal layer, when the liquid crystal layer cannot be fully turned off, the subsequent green light G is lit, resulting in color mixing. Similarly, color mixing also occurs when the blue light B is lit. Figure 21B The text shows from Figure 21A The mixing ratio calculated from the response waveform diagram (b) (TN mode) shown, and from... Figure 21A The color mixing rate is calculated from the response waveform diagram (c) (1D-VA mode).

[0221] [Table 1]

[0222]

[0223] In Table 1, ※1 represents the content of compounds containing an alkenyl group, and ※2 represents the content of compounds having two or more phenyl groups per molecule. "%" in Table 1 refers to "weight %". These contents are values ​​relative to 100% by weight of the total amount of liquid crystal material (i.e., the total amount of the liquid crystal layer). It should be noted that since compounds equivalent to both ※1 and ※2 exist, the content may sometimes exceed 100% by weight if both conditions are met.

[0224] The liquid crystal display panel 1 has a first alignment film 21 and a second alignment film 22 between the first substrate 100 and the liquid crystal layer 200, and between the second substrate 300 and the liquid crystal layer 200, respectively. The first alignment film 21 and the second alignment film 22 are preferably photoalignment films. These photoalignment films, by forming a photoalignment film material and performing a photoalignment treatment, exhibit the function of aligning liquid crystal molecules 210 in a specific direction. The photoalignment film material refers to a material whose structure changes upon irradiation with ultraviolet light, visible light, or other light (electromagnetic waves), exhibiting properties (alignment constraint forces) that restrict the orientation of liquid crystal molecules 210 present nearby, and the overall material exhibiting changes in the magnitude and / or direction of these alignment constraint forces.

[0225] Photo-aligned film materials may include photoreactive sites that undergo dimerization (dimer formation), isomerization, photofrighese rearrangement, and decomposition reactions upon light irradiation. Examples of photoreactive sites (functional groups) undergoing dimerization and isomerization upon light irradiation include cinnamate, cinnamyl, 4-chalcone, coumarin, and stilbene. Examples of photoreactive sites (functional groups) undergoing isomerization upon light irradiation include azobenzene. Examples of photoreactive sites undergoing photofrighese rearrangement upon light irradiation include phenolic ester structures. Examples of photoreactive sites undergoing decomposition upon light irradiation include dianhydrides containing a cyclobutane ring, such as 1,2,3,4-cyclobutanetetracarboxylic acid-1,2:3,4-dianhydride (CBDA). Furthermore, photo-aligned film materials preferably exhibit vertical orientation properties that allow for use in a vertical alignment mode. Examples of photo-aligned film materials containing photoreactive sites include polyamides (polyamic acid), polyimides, polysiloxane derivatives, methyl methacrylate, and polyvinyl alcohol.

[0226] In addition, in this embodiment, polymer-stabilized alignment (PSA) technology can be used. PSA technology involves encapsulating a liquid crystal composition containing photopolymerizable monomers between a first substrate 100 and a second substrate 300, and then irradiating the liquid crystal layer 200 with light to polymerize the photopolymerizable monomers, thereby forming a polymer on the surfaces of the first alignment film 21 and the second alignment film 22. This polymer is then used to fix the initial tilt (pre-tilt) of the liquid crystal.

[0227] In this embodiment, the liquid crystal display panel 1 uses a sealing member disposed to surround the liquid crystal layer 200 to bond the first substrate 100 and the second substrate 300, thereby holding the liquid crystal layer 200 within a predetermined area. As a sealing material, for example, epoxy resin containing inorganic or organic fillers and a curing agent can be used.

[0228] The liquid crystal display panel 1 may also have a polarizing plate. In this case, the liquid crystal display panel 1 preferably has, from the back side to the viewing side, a first polarizing plate 11, a first substrate 100, a first alignment film 21, a liquid crystal layer 200 made of liquid crystal material containing liquid crystal molecules 210, a second alignment film 22, a second substrate 300 and a second polarizing plate 12 in sequence.

[0229] The polarization axis of the first polarizing plate 11 and the polarization axis of the second polarizing plate 12 can be configured to be orthogonal to each other (i.e., orthogonal Nicol) or parallel to each other (i.e., parallel Nicol). It is preferred to configure them to be orthogonal to each other.

[0230] Examples of the first polarizing plate 11 and the second polarizing plate 12 include polarizing elements (absorption-type polarizing plates) formed by dyeing a polyvinyl alcohol film and adsorbing anisotropic materials such as iodine complexes (or dyes) and then extending and oriented them. Furthermore, to ensure mechanical strength or resistance to damp heat, they are typically provided in a practical state with protective films such as triacetyl cellulose films laminated on both sides of the polyvinyl alcohol film. The first polarizing plate 11 and the second polarizing plate 12 are arranged in an orthogonal Nicol configuration with their polarization axes orthogonal to each other. Additionally, optical films such as retardation films can be disposed between the first polarizing plate 11 and the first substrate 100, and between the second polarizing plate 12 and the second substrate 300.

[0231] In addition to the components described above, the liquid crystal display panel 1 consists of external circuits such as TCP (tape-on-a-chip), PCB (printed wiring board), optical films such as viewing angle enhancement film and brightness enhancement film, and an outer frame, etc., and these components can also be assembled into other components. There are no particular limitations on components other than those already described; components commonly used in the field of liquid crystal display panels can be used, therefore, descriptions are omitted.

[0232] The manufacturing method of the liquid crystal display panel 1 is not particularly limited, and methods commonly used in the field of liquid crystal display panels can be used. For example, the alignment processing of the first alignment film 21 and the second alignment film 22 can be performed by optical alignment processing using light (electromagnetic waves) such as ultraviolet light or visible light. The optical alignment processing can be performed using an apparatus such as a light source that irradiates the first alignment film 21 and the second alignment film 22, and an apparatus capable of performing continuous scanning exposure of multiple pixels. Specific methods of scanning exposure include, for example, irradiating the substrate surface with light emitted from the light source while moving the substrate, irradiating the substrate surface with light emitted from the light source while moving the light source, and irradiating the substrate surface with light emitted from the light source while moving both the light source and the substrate.

[0233] The liquid crystal display panel preferably has an RP value of 3.66 or less, as expressed by the following formula (1).

[0234] RP value = (γ1 / K) 33 )×{(d d ) 2 / (d b ) 2}(1)

[0235] (In the formula, γ1 represents the rotational viscosity coefficient of the liquid crystal material (mPa·s). K 33 d represents the bending elasticity coefficient of liquid crystal molecules. d This indicates the thickness (μm) of the liquid crystal layer. b The value is 3 (μm). In this case, the decreasing response speed can be accelerated while maintaining high transmittance, further achieving a wide color gamut. In addition, since the increasing response speed is also accelerated, further improvement in monochromatic brightness can be expected. The RP value is more preferably 3.6 or less, more preferably 3.55 or less, particularly preferably 3.5 or less, and most preferably 3.46 or less.

[0236] In this specification, the bending elastic constant K 33 The elastic coefficient of liquid crystals can be obtained through methods such as magnetic field-based measurement methods, electric field-based measurement methods, methods according to JEITA ED-2521D's "5.9 Method for Measuring the Elastic Coefficient of Liquid Crystal Materials", methods for measuring the elastic coefficient of liquid crystals as described in Japanese Patent Application Publication No. 2004-286485, and methods that calculate the elastic coefficient by fabricating parallel alignment cells and measuring the voltage dependence of the capacitance (CRIG MAZE, Mol. Cryst. Liq. Cryst., Vol. 48, 273 (1978)). In this invention, the value obtained by the "5.9 Method for Measuring the Elastic Coefficient of Liquid Crystal Materials" in JEITA ED-2521D (flexural elastic coefficient K) is preferred. 33 ).

[0237] When the RP value is 3.66, the thickness d of the liquid crystal layer in the liquid crystal display panel 1 is preferably [value missing]. d It is 2.51 or less. More preferably, it is 2.44 or less.

[0238] Furthermore, the fall-edge response property of the liquid crystal display panel is preferably 2.55 ms or less. In this case, a wider color gamut can be further achieved. The fall-edge response property is more preferably 2.08 ms or less, and even more preferably 0.5 ms or less.

[0239] The liquid crystal display panel preferably has a rise time of 2.75 ms or less. This allows for further improvement in monochrome brightness. A rise time of 2.08 ms or less is more preferred, and 1.35 ms or less is even more desirable.

[0240] In this specification, when the normalized brightness of the response waveform at 10% is set as the black display state, and the normalized brightness of the response waveform at 90% is set as the white display state (with the maximum integral value set to 100%), the falling response property (also called falling response time) is the time (m seconds) of optical change from the white display state to the black display state. Similarly, when the normalized brightness of the response waveform at 10% is set as the black display state, and the normalized brightness of the response waveform at 90% is set as the white display state (with the maximum integral value set to 100%), the rising response property (also called rising response time) is the time (m seconds) of optical change from the black display state to the white display state. Sometimes, m seconds is also denoted as msec.

[0241] Generally, it is known that if the viscosity coefficient η of the liquid crystal material is reduced, the thickness d of the liquid crystal layer will decrease. d Furthermore, increasing the applied voltage V for white display or increasing the anisotropy of the dielectric constant Δε of the liquid crystal molecules can achieve a high-speed response. Additionally, the halftone (also known as mid-gray) response of the liquid crystal display panel can be increased by increasing the voltage difference (VV). th The OD (overdrive) driver adjusts the response speed to achieve high speed.

[0242] Table 2 shows more detailed properties of the liquid crystal materials (a), (c1), and (c3) described in Table 1. Furthermore, the properties of liquid crystal material (c2), which provides a liquid crystal display panel in 1D-VA mode, are also described, as they differ from those of liquid crystal materials (c1) and (c3).

[0243] [Table 2]

[0244] (a) (c1) (c2) (c3) Transmittance (7V) 100％ 93％ 100％ 100％ Birefringence Δn 0.1399 0.1246 0.1246 0.108 thickness of liquid crystal layer 2.4μm 2.4μm 2.6μm 3.0μm RP value 3.46 3.27 3.84 7.61 Decreasing response time 2.39msec 2.25msec 2.64msec 5.82 msec NTSC ratio 92％ 92％ 89％ 59％

[0245] (Implementation Method 2)

[0246] Next, it will be explained that the liquid crystal display device is a device for transparent display on a transparent background (i.e., a transparent display). Descriptions that are repeated in Embodiment 1 will be omitted. In this embodiment, the liquid crystal display device is a transparent display, enabling new displays that are not possible in conventional display devices.

[0247] Figure 22 This is a cross-sectional schematic diagram of the liquid crystal display device (transparent display) according to this embodiment. The transparent display 1000 shown in FIG2 includes a box-shaped housing 2, a liquid crystal display panel 1 disposed on one side of the housing 2, a light source 3 disposed on the side inside the housing 2, and a controller 4. In this figure, the controller 4 is disposed on the outside of the housing 2, but it may also be disposed on the inside of the housing 2.

[0248] The liquid crystal display panel 1 in this embodiment is a transparent panel. Light from the light source 3 is incident on the transparent panel (liquid crystal display panel) 1, and the orientation of the liquid crystal molecules 210 of the liquid crystal layer 200 is switched, thereby controlling the amount of light transmitted through the liquid crystal display panel 1. The liquid crystal display panel 1 is configured to display an image on the panel surface in the image display state and allow the background to be transmitted through in the transparent display state. When the transparent panel is in the transparent display state, the observer can visually identify the background (in this case, the interior of the housing 2) through the transparent panel. In this way, transparent display is possible. The transparent panel can switch between image display state and transparent display state on a pixel-by-pixel basis. Therefore, it is also possible to operate in a manner that allows the background to be transmitted through only a portion of the panel surface.

[0249] In this embodiment, the liquid crystal display panel (transparent panel) 1 is driven in an FSC mode using a light source 3 and a controller 4. The light source 3 sequentially illuminates the liquid crystal display panel 1 with red light R, green light G, and blue light B. To maximize the amount of light from the light source 3 incident on the liquid crystal display panel 1, the inner surface of the housing 2 can also have light diffusion characteristics. Furthermore, if the inner surface of the housing 2 is made white, all colors of light can be effectively reflected, thus increasing the amount of light directed toward the liquid crystal display panel 1 for any of the red light R, green light G, and blue light B.

[0250] Transparent displays are used in various fields, including smart glasses, automobiles, digital signage, building materials, smart home appliances, and entertainment. In smart glasses, for example, applying transparent displays to head-mounted displays enables Mixed Reality (MR) and Virtual Reality (VR). In the automotive industry, for example, applying transparent displays to head-up displays allows for the display of maps, speed, traffic information, and can also be used as sun visors and blackout curtains. In digital signage, applying transparent displays to vending machines, wayfinding panels, and tram platform doors enables advertising displays that blend seamlessly into the landscape. In building materials, applying transparent displays to display cases, windows, and partitions allows for the display of descriptions and images. In smart home appliances, applying transparent displays to transparent televisions and refrigerators reduces the oppressive feeling of the appliances when not in use. In entertainment, applying transparent displays to gaming monitors, pachinko machines, and vending machines enhances presentation effects.

[0251] The liquid crystal display device (transparent display) in this embodiment is in a normally black mode. That is, the liquid crystal display panel 1 (transparent panel) is in a normally black mode. By adopting this method, the contrast of the liquid crystal display panel 1 can be further improved. Here, normally black mode refers to a display mode that displays black when no voltage is applied and displays white when voltage is applied.

[0252] (Variation Example 1)

[0253] Figure 23 This is a schematic diagram showing the relationship between the liquid crystal alignment axis and the polarization axis of the liquid crystal display panel in the liquid crystal display device of Modified Example 1. In Embodiment 1, it is described that in each pixel 1P overlapping with a single pixel electrode 120, the first alignment film 21 and the second alignment film 22 are aligned in the column direction with first domain 1Pa and second domain 1Pb having different alignment vectors 210V (210Va, Vb). However, it is also possible to... Figure 23 As shown, the first alignment film 21 and the second alignment film 22 overlap with one of the first pixels 1P1 and the second pixels 1P2 that are adjacent to each other in the column direction (e.g., Figure 23 The first pixel 1P1 is configured with only the first domain 1Pa, and another pixel in the first pixel 1P1 and the second pixel 1P2 (e.g., Figure 23 The second pixel (1P2) is oriented by configuring only the second domain 1Pb. According to this method, the same effect as in Embodiment 1 can be obtained. In Embodiment 1, each pixel is a pixel with multiple domains, but in this variation, the pixels are pixels with a single domain.

[0254] In this modified example, a light-shielding body can also be provided at the boundary between the first domain 1Pa and the second domain 1Pb, that is, between the first pixel 1P1 and the second pixel 1P2. Since the liquid crystal orientation changes continuously at the boundary between the first domain 1Pa and the second domain 1Pb, there is a situation where the liquid crystal orientation axis 210Xa of the first domain 1Pa and the liquid crystal orientation axis 210Xb of the second domain 1Pb are not parallel, resulting in dark lines. However, by providing a light-shielding body at the boundary between the first domain 1Pa and the second domain 1Pb, the dark line portion can be blocked, thereby further suppressing blurring.

[0255] (Variation Example 2)

[0256] In embodiment 2, the method of providing the light source 3 on the side of the housing 2 is described. However, the light source 3 only needs to be positioned so as not to obstruct the view of the back side of the liquid crystal display panel 1 in the transparent display state. For example, it can also be provided on the top plate of the housing 2.

[0257] (Variation Example 3)

[0258] In Embodiment 2, it is described that the liquid crystal display panel 1 is provided on one side of the box-shaped housing 2, and the light source 3 is provided inside the housing 2. However, the liquid crystal display panel 1 is not provided in the housing 2 with the light source 3. As long as there is light incident from the back side of the liquid crystal display panel 1, it can be used as a transparent display.

[0259] The embodiments of the present invention have been described above, but all the matters described can be applied to the whole of the present invention.

[0260] While embodiments and comparative examples are disclosed below, and the invention is described in more detail, the invention is not limited to these embodiments.

[0261] (Example 1-1)

[0262] The liquid crystal display panel included in the liquid crystal display device of Embodiment 1 is manufactured to have... Figure 18 The structure shown has Figure 24 The liquid crystal display panel shown is in the alignment state (2D-ECB parallel alignment mode). The liquid crystal layer uses the liquid crystal materials (a) listed in Tables 1 and 2. The pixel pitch is 120 μm × 360 μm, and the tilt angle (referring to the pretilt angle of the liquid crystal molecules) is 88.6°. No slits are provided at the pixel electrode 120. Three such liquid crystal display panels are manufactured (referred to as No.1, No.2, and No.3). Using each liquid crystal display panel, the physical properties are evaluated according to the evaluation method described below. The results are shown in... Figure 25 In the evaluation, a light source (backlight) and a controller are connected to the liquid crystal display panel to form a liquid crystal display device that performs color display via FSC driving. Figure 25 In this context, "average" refers to the average evaluation results when using LCD display panels No.1 to No.3.

[0263] (Comparative Example 1-1)

[0264] A TN-mode liquid crystal display panel was fabricated, and the same evaluation tests as in Example 1-1 were conducted. In Comparative Example 1-1, the brightness of Example 1-1 differed from that of the B / L (white backlight source provided on the liquid crystal display panel). The results are as follows... Figure 25 As shown. The results are presented in... Figure 25 middle.

[0265] (Evaluation Method)

[0266] (1) White brightness and black brightness

[0267] The white and black brightness of the LCD panel were measured using a spectroradiometer (trade name "SR-UL2", manufactured by TOPCON TECHNOHOUSE).

[0268] (2) Transmittance TA (Front / Rear Polarization Axis Alignment)

[0269] Transmittance T A The transmittance of the liquid crystal display panel is determined by the following formula (2) when the absorption axis of the first polarizing plate 11 is aligned with the absorption axis of the second polarizing plate 12.

[0270] T A (%) = (L) w1 / L w0 )×100 (2)

[0271] In the formula, L w1 The measured value of white brightness (unit: cd / cm) obtained by the above evaluation method (1) 2 L w0 This refers to the B / L brightness during measurement (white dot on the rear LCD) (unit: cd / cm). 2 ).

[0272] Here, "B / L brightness (rear LCD white light up) (unit: cd / cm)" is used. 2 This allows for measurement using white light from the backlight while the rear LCD (backlight, such as a TFT color TN panel) is set to white display mode. Specifically, in... Figure 16 In the measurement system shown, the light source 430 can be used as a white backlight, and a rear unit (e.g., a TFT color TN panel) can be set between the light source 430 and the TFT panel 420 (front unit: TFT white and black panel) to perform the measurement.

[0273] (3) Transmittance T B (Transmittance of a single unit in a liquid crystal display panel)

[0274] Transmittance T B (This means that the transmittance of the front panel unit when using a white backlight is calculated by the following formula (3).)

[0275] T B (%) = (L) w2 / L w3 )×100 (3)

[0276] In the formula, L w2 This refers to the brightness of the front panel unit when voltage (On) is applied (unit: cd / cm). 2 L w3 The brightness of the white backlight (unit: cd / cm) 2 ).

[0277] (4) Mode efficiency M

[0278] The mode efficiency M means the mode efficiency of the front panel unit when using a white backlight, which is calculated by the following formula (4).

[0279] M(%)=(L w4 / L w5 )×100 (4)

[0280] In the formula, L w4 This pertains to the brightness (unit: cd / cm) of a polarizer with polarizing plates orthogonally arranged on both sides of a single front panel unit when voltage is applied (On). 2 L w5 This refers to the brightness (unit: cd / cm) of a front panel unit with polarizing plates arranged parallel to each other on both sides without applied voltage (Off). 2 ).

[0281] (5) Contrast C

[0282] The contrast ratio C is obtained by the following equation (5).

[0283] C(%)=(L w1 / L B )×100 (5)

[0284] In the formula, L w1 The measured value of white brightness (unit: cd / cm) obtained by the above evaluation method (1) 2 L B The measured value of blackness (unit: cd / cm) obtained by the above evaluation method (1) 2 ).

[0285] ⑹ Color

[0286] According to the above NTSC measurement method (refer to...) Figure 16 ), calculate the NTSC ratio.

[0287] In Example 1-1, a dark-line-free orientation can be achieved, along with high transmittance and high mode efficiency. Specifically, it is known that the transmittance of the liquid crystal display panel alone can reach 25% or more, and the NTSC ratio can reach 90% or more. Moreover, these transmittance and NTSC ratio exceed the values ​​of the TN mode (Comparative Example 1-1). Regarding contrast ratio, it is more than 10 times that of the TN mode (Comparative Example 1-1), and improved performance can be expected when combined with a backlight.

[0288] (Examples 1-2)

[0289] The response characteristics of the liquid crystal display device manufactured in Example 1-1 were analyzed. Figure 1 (a) shows the response waveform. Figure 1In the diagram, the horizontal axis is set to time (m seconds), and the vertical axis is set to the normalized brightness (monochrome display) when the waveform input is on-off-off. The light source is lit in the order of red (R), blue (B), and green (G). Based on this response characteristic, the brightness (normalized brightness) of the monochrome display was studied (see reference). Figure 26A as well as Figure 26B ). Figure 26A This is a graph evaluating the brightness of a monochrome display based on the brightness when displaying white (white brightness). When white brightness is set to 100%, the ratios of the combined brightness of red, green, and blue are 94% (48% + 25% + 20%), 94% (22% + 67% + 5%), and 99% (1% + 9% + 89%), respectively. Furthermore, the brightness values ​​within parentheses are recorded after discarding decimal places from the measured values. On the other hand, since the combined brightness is calculated directly using measured values, some of the calculated values ​​may appear inconsistent.

[0290] Figure 26B This shows a display image from the device. In this device, from... Figure 26A It is known that the brightness is high enough for monochrome displays, therefore, Figure 26B In the image, the flowers, leaves, sky, and clouds of the Hibiscus genus are displayed in natural hues.

[0291] (Comparative Examples 1-2)

[0292] For the liquid crystal display device (TN mode) fabricated in Comparative Example 1-1, the response characteristics are analyzed and the brightness of the monochrome display is studied. Figure 1 (b) shows the response waveform. Figure 2A and Figure 2B The results of a study on the brightness of monochrome displays are shown below. The analysis is as described above.

[0293] Table 3 shows the data from... Figure 1 The rise and fall response speeds (msec, i.e., ms seconds) were obtained from the response waveform diagram shown. Table 3 also records the response speed using a 1D-VA mode liquid crystal display panel as Reference Example 1. In this 1D-VA mode liquid crystal display panel, liquid crystal material 1 and the liquid crystal material (c1) shown in Table 2 were used as liquid crystal materials. Furthermore, in each example, the thickness of the liquid crystal layer was 2.4 μm.

[0294] [Table 3]

[0295] Examples 1-2 Reference Example 1 Comparative Examples 1-2 Rising response / msec 1.35 1.44 4.8 Drop response / msec 2.27 2.16 0.5

[0296] Typically, in color displays driven by an FSC, similar to color gamut, monochrome brightness is also affected by insufficient response of the liquid crystal layer. However, in Examples 1-2, the rise response is faster than in Comparative Examples 1-2 (TN mode) or Reference Example 1 (1D-VA mode), resulting in excellent monochrome brightness. Furthermore, the ratio of the combined brightness of red, blue, and green to 100% of the white brightness (ideally 100%) is 56% in Comparative Examples 1-2, while it is 94% in Examples 1-2 (when green is displayed). That is, in Comparative Examples 1-2 (TN mode), the brightness changes according to the color of the image, becoming darker the more RGB primary colors are displayed, thus creating an unnatural display that disrupts the brightness balance. However, this phenomenon does not occur in Examples 1-2.

[0297] (Examples 1-3)

[0298] The viewing angle characteristics of the liquid crystal display device fabricated in Example 1-1 were evaluated. Specifically, the device displays a color original image via FSC driving, and a camera is used to view the image from... Figure 27 The images shown are captured from various angles (images captured from various angles, at a 45-degree polar angle). In embodiments 1-3, the liquid crystal display panel is set as... Figure 28A As shown, the vertical orientation serves as the original image for color, using... Of the four types of images shown, Figure 29B Image (2) and Figure 29C Image (3). The results are shown in Figure 30 middle.

[0299] Furthermore, the orientation of the liquid crystal molecules 210 when the liquid crystal display panel is placed vertically is conceptually shown on the left side of Figure 28.

[0300] In this specification, polar angle refers to the angle between the direction of the object (e.g., the measurement direction) and the normal direction of the screen of the liquid crystal display panel. Azimuth refers to the direction in which the direction of the object is projected onto the screen of the liquid crystal display panel, expressed as the angle (azimuth angle) formed between it and the reference azimuth. Here, the reference azimuth (0°) is set to the horizontal right direction of the screen of the liquid crystal display panel. The angle and azimuth angle are defined as follows: counterclockwise is positive, and clockwise is negative. Both counterclockwise and clockwise directions represent the rotation direction when viewing the screen of the liquid crystal display panel from the viewing side (front). Additionally, the angle represents the value measured when looking down at the liquid crystal display panel.

[0301] (Comparative Examples 1-3)

[0302] Regarding the liquid crystal display device (TN mode) fabricated in Comparative Example 1-1, the viewing angle characteristics were evaluated in the same manner as in Examples 1-3. In Comparative Examples 1-3, the liquid crystal display panel was set as... Figure 28B As shown, it is horizontally positioned. The results are presented in... Figure 30 In addition, Figure 3A and Figure 3B yes Figure 30 Excerpts of the results from Comparative Examples 1-3 are shown.

[0303] In Examples 1-3, the left and right field of view characteristics were prioritized during shooting, resulting in the display of objects both vertically and horizontally. Furthermore, no black spots or grayscale inversion were observed. In contrast, in Comparative Examples 1-3, as described above, asymmetrical vertical display was obtained, and black spots and grayscale inversion occurred. Thus, it was confirmed that the field of view performance of Examples 1-3 is overwhelmingly superior to that of Comparative Examples 1-3.

[0304] The viewing angle characteristics of Examples 1-3 and Comparative Examples 1-3 were evaluated in more detail. The results are shown in... Figures 31A to 31F Additionally, in Figure 31B In Examples 1-3 and Comparative Examples 1-3, the backlights (light sources) are different, so the brightness and hue of the front are inconsistent.

[0305] according to Figure 31A and Figure 31B In Examples 1-3, even when comparing the left and right directions, a symmetrical display is obtained, and no grayscale inversion (white inversion) occurs in the up and down directions, thus confirming that the viewing angle performance is excellent.

[0306] Figure 31C Uses a white backlight and an LCD display panel. Figure 29B The image shown (2) is used as the original image. The results of the isotactic analysis of the viewing angle are based on the results of full illumination and measurement while changing the display grayscale. White is set to 255 grayscale (255th level) and black is set to 0 grayscale (0th level). The peripheral part is the contrast at an 88-degree polar angle. According to the figure, it can be seen that in Examples 1-3, the viewing angle is well balanced in all directions, and the contrast viewing angle is wider than that of Comparative Examples 1-3.

[0307] Figure 31D Based on using a white backlight to illuminate the LCD panel (using...) Figure 29BThe image (2) shown is the original image. The contrast was analyzed by measuring the image while the grayscale was being changed. White was set to 255 gray levels (255 levels), and black was set to 0 gray levels (0 levels). When the polar angle ±90 degrees is taken as the contrast = 0 (zero), the polar angle with a contrast of 10 or higher is calculated. The horizontal axis of each graph represents the polar angle (degrees), and the vertical axis represents the contrast. In Examples 1-3, the viewing angles with a contrast of 10 or higher are 179.7 degrees in the left-right direction, 179.7 degrees in the up-down direction, and 179.9 degrees in the tilt direction. In Comparative Examples 1-3, the viewing angles with a contrast of 10 or higher are 178.1 degrees in the left-right direction, 144.1 degrees in the up-down direction (up: 89.2 degrees, down: 54.9 degrees), and 179.0 degrees in the tilt direction. According to the graph, it can be seen that compared with Comparative Examples 1-3, the contrast is higher in Examples 1-3, especially the viewing angle is wider in the up-down direction. Furthermore, in comparative examples 1-3, the asymmetric viewing characteristics in the vertical direction are particularly preferred.

[0308] Figure 31E Based on using a white backlight to illuminate the LCD panel (using...) Figure 29B The image shown (2) is the original image. The results of the contrast analysis were obtained by lighting up all the images and measuring the grayscale while changing the display. The horizontal axis of each curve represents the polar angle (degrees), and the vertical axis represents the normalized brightness. According to the attached figure, in Examples 1-3, the viewing angle balance is good in all directions, while in Comparative Examples 1-3, the viewing angle characteristics in the vertical direction are asymmetrical.

[0309] Figure 31F Based on Figure 31A The display obtained in the middle (setting the original image as) Figure 29B The image shown (2) is the result of analyzing the γ curve during grayscale display. The front correction is set to γ ​​= 2.2, and the display is performed via FSC drive. In Examples 1-3, the liquid crystal display panel is set to... Figure 28A The graphs are shown vertically. The horizontal axis of each graph represents grayscale (…). The graph shows the γ curve (order) with the vertical axis representing transmittance. According to this graph, the left and right directions are approximately the same in Examples 1-3 and Comparative Examples 1-3, but the change in the γ curve in the downward direction is good in Examples 1-3.

[0310] Table 4 summarizes Example 1 (Example) ) and Comparative Example 1 (Comparative Example) A comparison of ).

[0311] [Table 4]

[0312]

[0313] (Comparative Example 2)

[0314] A liquid crystal display device was fabricated using a 1D-VA mode liquid crystal display panel (TFT panel), and the generation of vertical stripes in monochrome display was investigated. The results are shown below. Figures 32A-32C .

[0315] Figure 32A In the image, a red display is shown on the left when the black voltage is set to 0.5V, and a green display is shown on the right. Vertical stripes are confirmed to be produced at 5mm intervals (spacing). Figure 32B The study confirmed whether the generation of vertical stripes depends on the magnitude of the black voltage. × indicates that vertical stripes were generated, and 〇 indicates that no vertical stripes were generated. Both strong and weak friction were investigated under normal tilt (pretilt angle of liquid crystal molecules greater than 88.5 degrees). Furthermore, the evaluation for low tilt (pretilt angle of liquid crystal molecules between 86 and 87 degrees) is a presumptive evaluation. Figure 32C The image shows the vertical stripe formation status of the test unit.

[0316] (Examples 2-1, 2-2, 2-3)

[0317] The liquid crystal display panel included in the liquid crystal display device of Embodiment 1 is manufactured to have... Figure 18 The structure shown has Figure 24 The liquid crystal display panel (2D-ECB parallel alignment mode) is shown in the alignment state. The pixel pitch is 120μm × 360μm. The tilt angle is 88.5 degrees in Examples 2-1 and 2-3 (liquid crystal layer thickness is 2.4μm), and 87 degrees in Example 2-2 (liquid crystal layer thickness is 2.4μm). Furthermore, for the liquid crystal display panels of Examples 2-1 and 2-3, only the panel prototype flow date differs; the liquid crystal optical conditions (tilt, retardation) are the same. No slits are provided at the pixel electrode 120. The liquid crystal display panel thus fabricated is connected to a light source and a controller to form a liquid crystal display device that performs color display via FSC driving, and various physical properties are measured. The results are shown in Table 5.

[0318] pass Figure 33 Measurements were performed using the configuration shown. An RGB backlight and a 19-type panel (with a color filter) were installed on the inside (back side), and a perspective panel (without a color filter) was installed on the front (viewing side) as the liquid crystal display panel of this embodiment. The reference voltage was set to the voltage at "normal PI (2.4μm) gamma 2.2 setting" (PI at an 88.5-degree tilt angle, with grayscale brightness characteristics set to γ2.2). Measurements were performed in a constant temperature atmosphere of 25°C.

[0319] In Table 5, B / L is Figure 33The brightness of the RGB backlight configuration shown is the brightness as it is transmitted through a panel with a color filter. White brightness, black brightness, transmittance (front / rear polarizer alignment), CR ratio (contrast ratio), and NTSC ratio are evaluated in the same manner as in Example 1-1. NTSC ratio is calculated according to... Figure 34 The results are calculated as the xy area ratio. The response speed (response time) is evaluated as follows. In Table 5, the values ​​for Examples 2-1 and 2-2 are the average values ​​after three trials, and the value for Example 2-3 is the value after one trial.

[0320] (Response time (average across all gray levels))

[0321] Use and Figure 17A The measurement method shown (NTSC ratio measurement method) uses the same test unit to measure response time. Specifically, the initial grayscale is set at 32 grayscale levels between 0 and 255, and the final grayscale is set at 32 grayscale levels between 0 and 255. The response time during arbitrary grayscale transitions is measured using a matrix. The results are shown below. Figure 35 And in Table 5. The "average of all gray levels" in Table 5 refers to... Figure 35 The average response time of the (9x9) matrix shown.

[0322] [Table 5]

[0323]

[0324] As shown in Table 5, good results were obtained in all examples 2-1 to 2-3. In Example 2-2, compared to Example 2-1, the white brightness was 1.07 times, the black brightness was 5.13 times, and the response time was shortened by 0.88 times, resulting in good performance. While the NTSC ratio appears low at first glance compared to Example 2-1, considering the shortened response time (average across all gray levels), it can be assessed that the color gamut, including intermediate gray levels, has been improved.

[0325] The response time was further analyzed for Examples 2-1 and 2-2. The results are shown in Table 6. In Table 6, the rise response time (m seconds) is the time required to transition from a white display state (0 grayscale) to a black display state (255 grayscale), and the fall response time (m seconds) is the time required to transition from a black display state (255 grayscale) to a white display state (0 grayscale).

[0326] [Table 6]

[0327]

[0328] The various aspects of the present invention described above can be appropriately combined without departing from the spirit of the invention.

[0329] Explanation of reference numerals in the attached figures

[0330] 1: LCD display panel

[0331] 1P, 1P1, 1P2: pixels

[0332] 1Pa, 1Pb: domains

[0333] 2: Shell

[0334] 3: Light source

[0335] 4: Remote Control

[0336] 5: Rotor

[0337] 6: Sample

[0338] 7: Constant temperature room, constant temperature bath

[0339] 10Xa, 10Xb: Polarizing axis 11: First polarizing plate:

[0340] 12: Second polarizing plate

[0341] 21: First orientation film

[0342] 22: Second orientation film

[0343] 100: First substrate

[0344] 110, 310: Insulating substrate

[0345] 120, 1201, 1202: Pixel electrodes

[0346] 200: Liquid Crystal Layer

[0347] 210: Liquid crystal molecule; 210S: Origin (tail of the liquid crystal pointing vector).

[0348] 210T: End point (head of the LCD pointer arrow)

[0349] 210V, 210Va, 210Vb: Orientation vectors; 210X, 210Xa, 210Xb: Liquid crystal alignment axes; 300: Second substrate.

[0350] 320: Common electrode

[0351] 1000: Transparent Display

[0352] 400: Spectroradiometer

[0353] 410:Polarizing plate

[0354] 420: TFT panel

[0355] 430: FSC-driven light source

[0356] 440: Test Unit

Claims

1. A liquid crystal display device performing color display in a plurality of subframe periods included in one frame period by field sequential driving, characterized by the liquid crystal display device being a device performing transparent display of a see-through background, the liquid crystal display device including: a liquid crystal display panel which is a normally black mode; a light source which irradiates the liquid crystal display panel with light of a plurality of colors; and a controller which drives the light source so that light of a plurality of colors is irradiated to the liquid crystal display panel in time division, the liquid crystal display panel sequentially having: a first polarizing plate; a first substrate; a first alignment film; a liquid crystal layer; a second alignment film; a second substrate; and a second polarizing plate, wherein the first substrate has a plurality of pixel electrodes arranged in a matrix shape in a row direction and a column direction, and the liquid crystal layer is composed of a liquid crystal material containing liquid crystal molecules, when an orientation vector is defined with a long axis end portion on the first substrate side of the liquid crystal molecules as a starting point and a long axis end portion on the second substrate side as an end point, the liquid crystal layer has a first domain and a second domain in which the orientation vectors are different from each other when no voltage is applied, when the first domain and the second domain are viewed in plan, the orientation vector of the first domain and the orientation vector of the second domain have a parallel relationship with each other, a liquid crystal alignment axis of the first domain and a liquid crystal alignment axis of the second domain intersect at the same azimuth angle with respect to a polarizing axis of the first polarizing plate and at the same azimuth angle with respect to a polarizing axis of the second polarizing plate.

2. The liquid crystal display device according to claim 1, wherein when the first domain and the second domain are viewed in plan, an end point of the liquid crystal molecules included in the first domain is located on the second domain side more than a start point of the liquid crystal molecules included in the first domain, and an end point of the liquid crystal molecules included in the second domain is located on the first domain side more than a start point of the liquid crystal molecules included in the second domain.

3. The liquid crystal display device according to claim 1, wherein a birefringence Δn of the liquid crystal material is 0.12 or more.

4. The liquid crystal display device according to any one of claims 1 to 3, wherein a rotational viscosity coefficient γ1 of the liquid crystal material is less than 100 mPa·sec.

5. The liquid crystal display device according to any one of claims 1 to 3, wherein an RP value represented by the following formula (1) of the liquid crystal display panel is 3.66 or less, RP value = (γ1 / K 33 ) x {(d d ) 2 / (d b ) 2} (1) In the formula, γ1 represents a rotational viscosity coefficient of the liquid crystal material / mPa • s, K 33 represents a splay elastic coefficient of the liquid crystal molecules, d d represents a thickness of the liquid crystal layer / μm, d b is 3 μm.

6. The liquid crystal display device according to any one of claims 1 to 3, wherein the liquid crystal material contains a compound having an alkenyl group.

7. The liquid crystal display device according to any one of claims 1 to 3, wherein the liquid crystal material contains a compound having a phenyl group.

8. The liquid crystal display device according to any one of claims 1 to 3, wherein a pretilt angle of the liquid crystal molecules is 89° or less.

9. The liquid crystal display device according to any one of claims 1 to 3, wherein a falling response property of the liquid crystal display panel is 2.55 msec or less.

10. The liquid crystal display device according to any one of claims 1 to 3, wherein a rising response property of the liquid crystal display panel is 2.75 msec or less.

11. The liquid crystal display device according to any one of claims 1 to 3, characterized in that each of the frame periods respectively includes a subframe period corresponding to red, a subframe period corresponding to blue, and a subframe period corresponding to green, frequencies of the subframe periods are respectively 180 Hz or more.

12. The liquid crystal display device according to any one of claims 1 to 3, wherein in each of the frame periods, the subframe periods corresponding to red, blue, and green respectively include red, black, blue, black, green, and black in this order with a black display period corresponding to an extinguishing period of the light source interposed therebetween.

13. The liquid crystal display device according to any one of claims 1 to 3, characterized in that After the controller inputs a trigger signal every frame, it extinguishes the light source during the period from the start of the descent in the optical response waveform at the top of the liquid crystal display panel to 1.20~2.45m seconds within one frame.

14. The liquid crystal display device according to any one of claims 1 to 3, characterized in that, During at least one of the subframes, the scanning process of the liquid crystal display panel is performed more than twice at a frequency of 480 to 720 Hz.

15. The liquid crystal display device according to any one of claims 1 to 3, wherein The NTSC ratio is over 90%.

Images