Improved liquid crystal alignment quality and stability

Abstract

A method for manufacturing a liquid crystal (LC) display includes determining the amount of LC material to be used in the LC display, determining the amount of LC material and silane material to be mixed with the LC material based on the amount of LC material, mixing the amount of silane material with the amount of LC material to produce an LC mixture, and heat-treating the LC mixture in contact with the display substrate to bond at least a portion of the silane material to one or more surfaces of the display substrate, so that the silane material acts as a surfactant. The amount of silane material may constitute at least 0.8% by weight of the LC mixture.

Description

Technical Field

[0001] Cross - reference to Related Applications This patent application claims the benefit of U.S. Patent Application No. 18 / 664,986, filed on May 15, 2024, which in turn claims the benefit of U.S. Provisional Patent Application No. 63 / 506,970, filed on June 8, 2023, entitled "Improved Liquid Crystal Alignment Quality and Stability", the entire contents of which are incorporated herein by reference.

[0002] The present disclosure generally relates to display devices, and more particularly to nematic liquid crystals and chiral nematic liquid crystal spatial light modulators.

Background Art

[0003] Liquid crystal spatial light modulators (SLMs) for imaging applications include SLMs using ferroelectric liquid crystals, SLMs using nematic liquid crystals, and SLMs using chiral nematic liquid crystals. Nematic - type liquid crystals can have positive or negative dielectric anisotropy. SLMs using nematic liquid crystals or chiral nematic liquid crystals having negative dielectric anisotropy use electro - optical modes including the vertically aligned nematic (VAN) display mode and the twisted vertically aligned nematic (TVAN) display mode, and typically have a higher contrast ratio. Of these two optical modes, the TVAN optical mode has the highest contrast ratio and is preferred for near - to - eye applications such as projection applications and mixed reality (MR) (e.g., augmented reality and virtual reality) head - sets. The TVAN optical mode is described in U.S. Patents Nos. 8,724,059 and 9,551,901, the entire contents of which are incorporated herein by reference.

[0004] SLMs using nematic or chiral nematic liquid crystals with negative dielectric anisotropy and operating in VAN or TVAN display modes present various technical challenges. High switching speed, high brightness, high contrast, and low power consumption are all desirable operating characteristics that require the use of specific LC materials and SLM designs, some of which exhibit sensitivity and instability that can reduce the reliability or robustness of the display. [Brief explanation of the drawing]

[0005] To facilitate the identification of any particular element or action, the leading digits of the reference number refer to the figure number in which that element was first introduced.

[0006] [Figure 1] This figure shows a method for manufacturing liquid crystal (LC) displays, with several examples.

[0007] [Figure 2] This figure shows the general molecular structures of exemplary silane molecules, based on several examples.

[0008] [Figure 3] This graph shows the fall time of an LC display against the cell gap width of a display, for a reference LC mixture and a 1% silane LC mixture, using several examples.

[0009] [Figure 4] This figure shows the display stability in energized and unenergized modes over 24 and 168 hours for a reference LC mixture, using several examples.

[0010] [Figure 5] This figure shows the display stability over time in energized and unenergized modes for a 1% silane LC mixture, using several examples.

[0011] [Figure 6] This figure shows the display transition from the nematic phase to the isotropic phase over a temperature process from 98°C to 103°C for a reference LC mixture, using several examples.

[0012] [Figure 7] This figure shows the display transition from the nematic phase to the isotropic phase over a temperature process from 98°C to 103°C for a 1% silane LC mixture, using several examples.

[0013] [Figure 8] This figure shows the display transition from the isotropic phase to the nematic phase over a temperature process from 105°C to 95°C for a reference LC mixture, using several examples.

[0014] [Figure 9] This figure shows the display transition from the isotropic phase to the nematic phase over a temperature process from 105°C to 95°C for a 1% silane LC mixture, using several examples. [Modes for carrying out the invention]

[0015] In some examples disclosed herein, methods for manufacturing LC displays, LC mixtures, and LC displays are provided that can provide improved LC orientation quality and stability compared to the prior art or conditions. A certain amount of silane material is mixed with a certain amount of LC material to produce an LC mixture containing a relatively high concentration of silane material, such as more than 0.8%, 0.8% to 1.2%, or about 1% silane material (in various examples). During the heat treatment of the LC mixture, which may involve heat treatment at a temperature of about 110°C for about 1 hour, the silane material bonds to the surface of the display substrate, thereby creating a layer of silane material between the substrate and the LC material, and the silane material acts as a surfactant. In some examples, the amount of silane material may be selected to ensure that the silane material bonds to the surface of the substrate and does not leave an excess amount of silane material mixed with the LC material, although such excess silane material may not significantly affect the operation of the LC material at low concentrations.

[0016] In some examples, the silane material may include or consist of one or more of the following: n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxysilane, octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane.

[0017] The use of silane materials at specific concentrations can exhibit one or more beneficial effects. As mentioned above, some optical applications (such as in-eye mixed reality displays) may require LC displays to exhibit high switching speeds in order to perform color sequential display. The need for high switching speeds may necessitate the use of displays with narrow or thin cell gaps. These optical applications may also require relatively high brightness and contrast. In relation to displays with thin cell gaps, LC materials with high birefringence may need to be used to form the LC display. To achieve the required high contrast, the LC display may need to operate in vertically aligned nematic (VAN) display mode, or, more advantageously in terms of contrast, in twisted vertically aligned nematic (TVAN) display mode. In TVAN or VAN display mode, LC molecules are oriented with a twist and nearly perpendicular to the substrate surface. The dielectric anisotropy of the LC material is negative in TVAN display mode (Δε = ε(n) - ε(o)).

[0018] To meet these requirements, in some examples, the display may need a switching speed of less than 500 microseconds to avoid, for example, color bleeding or motion defects. The display may need a cell gap of approximately 0.8 to 1.1 μm. The LC material in the display may need an LC birefringence of, for example, greater than 0.19. If at least one of a thinner cell gap and lower birefringence is used, brightness can be increased by increasing the LED current, but this leads to greater power consumption. In some examples, LC displays designed to meet these requirements may be implemented using a thin cell gap TVAN optical mode and a high birefringence LC material.

[0019] However, the use of high birefringence LC materials with negative dielectric anisotropy can present technical challenges. Achieving uniform LC orientation can be difficult. Some high birefringence LC materials with negative dielectric anisotropy have relatively low environmental stability, for example, being unstable to at least one of extreme humidity and temperature. Furthermore, these LC materials tend to have low anchoring transition temperatures, and the orientation of the LC material changes with increasing temperature. The anchoring transition temperature is the temperature at which LC molecules change their orientation configuration, for example, from nearly perpendicular to the display substrate to nearly parallel to the display substrate.

[0020] Various examples attempt to address one or more of these technical problems by adding surfactant materials to LC materials. Surfactants tend to reduce the surface tension of the liquid in which they are dissolved. Surfactant materials added to LC materials act to modify the properties of the surfaces they come into contact with, thereby potentially addressing one or more of the technical problems identified above.

[0021] In some examples, the surfactant material can be selected based on the ability of the surfactant material to chemically bond to a desired surface, such as the surface of a display substrate used to contain the LC material of an LC display. In some examples, a silane material such as a long-chain silane can be selected as the surfactant material. Various other factors can also be considered when selecting a suitable silane. First, it may be desirable for the silane to have a long alkyl chain in order to promote or improve the quality of the desired LC alignment (e.g., a substantially vertical alignment). This can increase the anchoring transition temperature. Second, it may be desirable for the silane to be highly hydrophobic or water-repellent in order to improve environmental stability. Third, it may be desirable for the silane not to change the electro-optical performance of the display if an excess amount of the silane remains mixed with the LC material after manufacture. Based on one or more of these factors, suitable long-chain silanes have been identified by the experimental tests described herein. These silanes include n-octadecyl dimethyl methoxysilane, n-octadecyl methyl dimethoxysilane, n-octadecyl trimethoxysilane, n-octadecyl methyl diethoxysilane, n-octadecyl triethoxysilane, octadecyl dimethyl (3-trimethoxysilyl-propyl) ammonium chloride, 1,2-bis(trimethoxysilyl) decane, and 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane.

[0022] In some examples, an LC mixture incorporating a relatively high concentration (e.g., 1%) of a highly hydrophobic silane (such as those identified above) can be used to effectively coat the alignment layer and bond to the substrate surface of an LC display, and can be particularly effective in the manufacture of very small LC displays such as an LC display with an area of approximately 1 square cm. Such displays, which can be used in demanding optical applications such as near-eye augmented reality displays, can have a very small cell gap (e.g., about 1 μm) and may require high brightness, high contrast, and fast switching times in order to effectively project full-color high-quality video to a viewer.

[0023] Examples of surfactant materials, LC mixtures, LC displays, and methods of manufacturing them are described herein with respect to various examples. Other technical features will be readily apparent to those skilled in the art from the following drawings, description, and claims.

[0024] FIG. 1 shows the operations of a method 100 for manufacturing a liquid crystal (LC) display. In some examples, the LC display is or includes a spatial light modulator configured to operate in a vertical alignment nematic (VAN) display mode. In some examples, the LC display is or includes a spatial light modulator configured to operate in a twisted vertical alignment nematic (TVAN) display mode.

[0025] The exemplary method 100 shows a particular order of operations, but the order can be changed without departing from the scope of the disclosure. For example, some of the illustrated operations can be performed in parallel or in a different order that does not substantially affect the functionality of method 100. In other examples, different components of an exemplary apparatus or system implementing method 100 can perform functions either substantially simultaneously or in a particular order.

[0026] In operation 102, an LC material is obtained. As described above, in some examples, the LC material is or includes a nematic LC material having negative dielectric anisotropy.

[0027] In operation 104, the amount of LC material to be used in the LC display is determined. The amount of LC material to be used in the LC display is typically determined by the structural design of the LC display.

[0028] In operation 106, the silane material to be mixed with the LC material is determined. As described above, various factors can be considered in this determination. For example, when the LC material is a nematic LC material with negative dielectric anisotropy, factors to be considered include the ability of the silane material to chemically bond to the desired surface, the length of the alkyl chain of the silane material, the hydrophobicity or water-repellency of the silane material, and the tendency of the silane material not to alter the electro-optical performance of the display.

[0029] In some examples, the molecular structure of a silane material contains two main components. Firstly, the silane material molecule contains a silane pendant group bonded to a silicon (Si) atom, which chemically bonds the silane molecule to the surface of the display substrate. Secondly, the silane material molecule contains an alkyl chain bonded to the silicon atom. The silane pendant groups in these silane molecules can consist of one or more OCH3 or OC2H5 groups. If the number of pendant groups is less than three, the remaining bonded parts of the Si atom may have CH2 groups bonded to them. The alkyl chain can consist of a chain of CH2 groups with the last group being a CH3 group. The length of the alkyl chain is defined by the number of carbon (C) atoms in the alkyl chain; the longer the alkyl chain, the higher the hydrophobicity of the display substrate surface after bonding with the corresponding silane. In some examples, the silane material may have a silane molecule with one or more silane pendant groups and an alkyl chain length of eight or more carbon atoms. Figure 2, described later, shows a typical molecular structure of an exemplary silane molecule.

[0030] In some examples, selected silane materials include n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxylsilane, octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane. Experimental testing of exemplary LC mixtures containing one or more of these silane materials demonstrates that when these silane materials are used in the manufacture of LC displays, as will be discussed later with reference to Figures 3 to 9, they may exhibit one or more desirable properties.

[0031] In step 108, the amount of silane material to be mixed with the LC material is determined. This amount can be determined based on the amount of LC material used in the LC display. For example, the amount of silane material can be selected as an amount that constitutes at least 0.8 wt% of the LC mixture resulting from the mixing of the silane material and the LC material (described in operation 110 below). In some examples, the amount of silane material can be selected as an amount that constitutes between 0.8 wt% and 1.2 wt% of the LC mixture resulting from the mixing of the silane material and the LC material. In some examples, the amount of silane material can be selected as an amount that constitutes approximately or exactly 1 wt% of the LC mixture resulting from the mixing of the silane material and the LC material. Experimental testing of exemplary LC mixtures containing about 1 wt% of silane material shows that these mixtures may exhibit one or more desirable properties when used in the manufacture of LC displays, as described later with reference to Figures 3 to 9.

[0032] In operation 110, the amount of silane material is mixed with the amount of LC material to produce an LC mixture. In some examples, the LC mixture may also contain one or more additional materials.

[0033] In operation 112, the LC mixture is brought into contact with the display substrate and heat-treated to bond at least a portion of the silane material to one or more surfaces of the display substrate, where the silane material acts as a surfactant. In some examples, the display substrate includes one or more solid components of the display, such as a cover glass component, a circuit backplane, and one or more electrodes. In some examples, the display substrate may include one or more plastic components, with or without indium tin oxide (ITO) electrodes. The heat treatment may include firing the display filled with the LC mixture in contact with the display substrate for various appropriate times at various appropriate temperatures, such as 110°C for 1 hour and 105°C to 115°C for at least 50 minutes.

[0034] In some cases, the amount of silane material is determined in operation 108 by estimating the amount of silane material that may bond to one or more surfaces of the display substrate during heat treatment, based at least partially on the display substrate. In some cases, silane material is selected in operation 106 such that even if some of the silane material remains mixed with the LC material after heat treatment, it will not significantly alter the properties or performance of the display. However, in some cases, it may be desirable to use only a minimum amount of silane material so that all or almost all of the silane material in the LC mixture bonds to the surface of the display substrate during heat treatment.

[0035] Figure 2 shows the typical molecular structure of an exemplary silane molecule 200, which includes an alkyl chain 202 and three silane pendant groups 204. The alkyl chain 202 contains 18 carbon atoms in the form of a CH3 group 206 and 17 CH2 groups 208.

[0036] Experimental tests were conducted to examine the properties of nematic and chiral nematic TVAN LC displays using conventional standard LC mixtures against the properties of such displays using LC mixtures, such as those described in various examples herein, for example, LC mixtures containing a relatively large amount of highly hydrophobic silane acting as a surfactant. Figures 3 to 9 show various results of these experimental tests, demonstrating the potentially beneficial properties of the LC mixtures, LC displays, manufacturing methods, and other techniques described herein.

[0037] Figure 3 shows a graph 300 of the fall time 302 of a TVAN LC display against the cell gap 304 width of the tested display for a reference LC mixture 306 and a 1% silane mixture 308. Two sets of displays were manufactured and tested, one using a reference LC mixture 306 derived from a conventional commercial LC mixture, and the other using an LC mixture containing approximately 1 wt% of silane material, referred herein as the 1% silane mixture 308. The reference LC mixture 306 contained less silane material by weight than the 1% silane mixture 308. The 1% silane mixture 308 used a silane material selected from the set of silane materials identified herein.

[0038] Graph 300 shows that displays using the 1% silane mixture 308 exhibit significantly faster switching speeds than displays using the reference LC mixture 306, as indicated by the fall time 302 of the display's LC material (e.g., the time required for the LC material to relax when the driving voltage is removed). The fall time 302 of the 1% silane mixture 308 displays is at least 30 microseconds, and typically over 50 microseconds, at measured cell gap 304 values ​​from 1 μm to 1.2 μm. Further improvements in LC display performance using the 1% silane mixture 308 are shown in Table 1 below. [Table 1] Table 1 LC display performance of a display using 1% silane mixture 308 compared to a display using standard LC mixture 306

[0039] The data in Table 1 shows that the absolute processing rate and on-time (e.g., LC rise time in relation to the drive voltage) of the two displays were not significantly different, while the 1% silane mixture 308 display exhibited significantly higher contrast at cell gaps of 1.1 μm and 1.2 μm, and significantly faster fall times at all test cell gap values.

[0040] The tests also demonstrated that, as shown in Table 2 below, the inclusion of a larger amount of highly hydrophobic silane material in the LC mixture did not significantly degrade the voltage holding ratio (VHR) of the display. [Table 2] Table 2 Voltage retention rate (VHR) of LC displays using 1% silane mixture 308 compared to displays using standard LC mixture 306.

[0041] Experimental tests also demonstrated that the 1% silane mixture 308 resulted in displays exhibiting improved environmental stability. Specifically, displays using the 1% silane mixture 308 showed improved stability of the LC material when exposed to high temperatures and high humidity for extended periods.

[0042] LC displays that satisfy the above required properties (e.g., using nematic or chiral nematic liquid crystals with negative dielectric anisotropy, operating in VAN or TVAN display mode, and having high birefringence LC material and a thin cell gap) may exhibit instability in response to at least one of high temperature and high humidity. For example, some such displays show visible degradation of the LC material when exposed to a temperature of 42°C and relative humidity (RH) of 92% for 96 hours, conditions that can exist in some environments, such as summer in some tropical climates, or in certain storage or transport environments. Therefore, experimental tests were conducted to test the relative environmental stability of a 1% silane mixture 308 display relative to a reference LC mixture 306 display.

[0043] Figure 4 shows the environmental stability of a display using a reference LC mixture 306 in energized and de-energized modes during 168 hours of exposure to a temperature of 65°C and relative humidity exceeding 90%. The top row shows the display in the de-energized state with no voltage applied, and the bottom row shows the display in the energized state with voltage applied. The first de-energized state 402 and the first energized state 408 at time 0 show uniform LC performance across the display area. The second de-energized state 404 and the second energized state 410 at time 24 show visible degradation of LC performance around the periphery of the display, particularly in the upper right corner. The third de-energized state 406 and the third energized state 412 at time 168 show further visible degradation of LC performance. Thus, the reference LC mixture 306 display exhibits significant environmental instability with highly visible degradation after 24 hours of exposure to high temperature and high humidity conditions.

[0044] Figure 5 shows the environmental stability of displays using 1% silane mixture 308 in energized and unenerged modes while exposed for the same time (168 hours) under the same conditions as in Figure 4 (temperature 65°C and relative humidity >90%). The second unenerged state 504 and the second energized state 510 show slight degradation around the thin peripheral area of ​​the display after 24 hours compared to the first unenerged state 502 and the first energized state 508, although this slight degradation may be obscured by the opaque boundary defining the display aperture in some designs. Furthermore, the third unenerged state 506 and the third energized state 512 at 168 hours show no significant change in appearance compared to 24 hours, demonstrating the long-term environmental stability of 1% silane mixture 308 displays even under extreme environmental conditions. In several tests, 1% silane mixture 308 displays showed stable performance even after being exposed for more than 1000 hours under 65°C and >90%RH conditions.

[0045] In addition to improved contrast, fall time, and environmental stability, experimental tests also demonstrated that displays fabricated using 1% silane mixture 308 showed an increased anchoring transition temperature above the nematic-isotropic phase transition temperature. This could mean that such displays may be able to operate at higher temperatures and with better overall stability than displays fabricated using the reference LC mixture 306.

[0046] Figure 6 shows the transition from the nematic phase to the isotropic phase of a display fabricated using a reference LC mixture 306 over a temperature process from 98°C to 103°C. Two such displays were tested and photographed to provide redundant testing and verification of the recorded results.

[0047] The images shown in Figure 6 begin with images of two displays fabricated using a reference LC mixture 306 in the nematic phase 602 at a temperature of 98°C. The arrows indicate that the appearance of the displays changes as the temperature rises, thereby causing the LC material of the displays to transition from the nematic phase to the isotropic phase, ending in the isotropic phase 604 of the two displays at a temperature of 103°C. The substantial heterogeneity of the LC material across the display regions can be seen in the intermediate transition images.

[0048] Figure 7 shows the transition from the nematic phase to the isotropic phase of a display fabricated using 1% silane mixture 308 over the same temperature range as in Figure 6 (i.e., from 98°C to 103°C). Two displays were tested and photographed, as in Figure 6.

[0049] The images shown in Figure 7 begin with images of two displays fabricated using a 1% silane mixture 308 in the nematic phase 702 at a temperature of 98°C. As shown in Figure 6, the arrows indicate that the appearance of the displays changes as the temperature rises, thereby causing the LC material of the displays to transition from the nematic phase to the isotropic phase, ending in the isotropic phase 704 of the two displays at a temperature of 103°C. Compared with Figure 6, the displays shown in Figure 7 exhibit considerably improved uniformity and visual performance during the phase transition.

[0050] The phase transition of the two LC mixtures was also tested in the reverse direction, from isotropic to nematic.

[0051] Figure 8 shows the transition from isotropic to nematic phase of two displays fabricated using a reference LC mixture 306 over a temperature process from 105°C to 95°C. Significant non-uniformity and degradation of visual performance can be observed as the display transitions from isotropic phase 802 to nematic phase 804.

[0052] Figure 9 shows the temperature process in Figure 8, i.e., the transition from isotropic phase 902 to nematic phase 904 of two displays fabricated using a 1% silane mixture 308, over a temperature range of 105°C to 95°C. As the displays transition from isotropic phase 902 to nematic phase 904, their visual performance and uniformity are significantly improved compared to the displays shown in Figure 8.

[0053] In some examples, methods for manufacturing LC displays, LC mixtures, and LC displays are provided that can offer improved LC orientation quality and stability compared to conventional techniques or conditions.

[0054] Example 1 is a method for manufacturing a liquid crystal (LC) display, comprising: determining the amount of LC material to be used in the LC display; determining the amount of silane material to be mixed with the LC material based on the amount of LC material; mixing the amount of silane material with the amount of LC material to produce an LC mixture; and heat-treating the LC mixture in contact with the display substrate to bond at least a portion of the silane material to one or more surfaces of the display substrate, thereby allowing the silane material to act as a surfactant.

[0055] In Example 2, the subject matter of Example 1 is as follows: determining the amount of silane material to be mixed with the LC material includes determining the amount of silane material that constitutes at least 0.8% by weight of the LC mixture.

[0056] In Example 3, the subject of Example 2 is as follows: determining the amount of silane material to be mixed with the LC material, which includes determining the amount of silane material comprising 0.8% by weight and 1.2% by weight of the LC mixture.

[0057] In Example 4, the subject matter of Examples 2 and 3 includes: determining the amount of silane material to be mixed with the LC material, which includes determining the amount of silane material that may bond to one or more substrate surfaces during heat treatment, at least partially, on the display substrate.

[0058] In Example 5, the subject matter of Examples 2 to 4 is as follows: Heat treatment of the LC mixture includes calcining the LC mixture at a temperature of 105°C to 115°C for at least 50 minutes.

[0059] In Example 6, the themes of Examples 2 to 5 are as follows: The silane material comprises a silane molecule having one or more silane pendant groups and an alkyl chain containing one or more carbon atoms.

[0060] In Example 7, the subject matter of Examples 2 to 6 is as follows: the silane material comprises n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxylsilane, octadecyldimethyl(3-trimethoxysilylpropyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane.

[0061] In Example 8, the subject of Example 7 is as follows: the silane material is n-octadecyldimethylmethoxysilane.

[0062] In Example 9, the subject matter of Examples 7 and 8 is as follows: the silane material is n-octadecylmethyldimethoxysilane.

[0063] In Example 10, the subject matter of Examples 7 to 9 is as follows: the silane material is n-octadecyltrimethoxysilane.

[0064] In Example 11, the subject matter of Examples 7 to 10 is as follows: the silane material is n-octadecylmethyldiethoxysilane.

[0065] In Example 12, the subject matter of Examples 7 to 11 is as follows: the silane material is n-octadecyltriethoxylsilane.

[0066] In Example 13, the subject matter of Examples 7 to 12 is as follows: the silane material is octadecidimethyl(3-trimethoxysilylpropyl)ammonium chloride.

[0067] In Example 14, the themes of Examples 2 to 13 are as follows: the LC material includes a nematic LC material or a chiral nematic LC material having negative dielectric anisotropy, and the LC display comprises a spatial light modulator configured to operate in a vertically aligned nematic (VAN) display mode.

[0068] In Example 15, the themes of Examples 2 to 14 are as follows: the LC material includes a nematic LC material or a chiral nematic LC material having negative dielectric anisotropy, and the LC display comprises a spatial light modulator configured to operate in a twisted vertical orientation nematic (TVAN) display mode.

[0069] Example 16 is a liquid crystal (LC) mixture for use in an LC display, comprising a certain amount of LC material and a certain amount of silane material determined based on the amount of LC material.

[0070] In Example 17, the subject of Example 16 is as follows: the amount of silane material is at least 0.8% by weight of the LC mixture.

[0071] In Example 18, the subject of Example 17 is as follows: the amount of silane material is between 0.8% by weight and 1.2% by weight of the LC mixture.

[0072] In Example 19, the subject matter of Examples 17 and 18 is as follows: The silane material comprises a silane molecule having one or more silane pendant groups and an alkyl chain containing one or more carbon atoms.

[0073] In Example 20, the subjects of Examples 17 to 19 include: silane materials comprising n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxylsilane, octadecyldimethyl(3-trimethoxysilyl-propyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane.

[0074] In Example 21, the themes of Examples 17 to 20 are as follows: the LC material comprises a nematic LC material or a chiral nematic LC material having negative dielectric anisotropy, and the LC display comprises a spatial light modulator configured to operate in a vertically aligned nematic (VAN) display mode or a twisted vertically aligned nematic (TVAN) display mode.

[0075] Example 22 is a liquid crystal (LC) display comprising a nematic LC material or chiral nematic LC material having negative dielectric anisotropy, configured to operate in a vertically aligned nematic (VAN) display mode or a twisted vertically aligned nematic (TVAN) display mode, a display substrate configured to include the nematic LC material or chiral nematic LC material, and a silane material bonded to one or more surfaces of the display substrate and disposed between the one or more surfaces and the nematic LC material or chiral nematic LC material, wherein the amount of silane material and the amount of nematic LC material or chiral nematic LC material A liquid crystal (LC) display comprising n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxysilane, octadecyltriethoxysilane, octadecyldimethyl(3-trimethoxysilyl-propyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane, present in amounts such that the ratio of the amount of Lunematic LC material is 0.8:99.2 to 1.2:98.8.

[0076] Example 23 is at least one machine-readable medium containing an instruction, which, when executed by a processing circuit, causes the processing circuit to perform an operation that is one of those in Examples 1 to 22.

[0077] Example 24 is an apparatus that includes means for carrying out any of Examples 1 to 22.

[0078] Example 25 is a system that performs any of Examples 1 through 22.

[0079] Example 26 is a method that follows any of Examples 1 to 22.

[0080] Modifications and alterations can be made to the disclosed embodiments without departing from the scope of this disclosure. These and other modifications are intended to be included within the scope of this disclosure, as set forth in the following claims.

Claims

1. A method for manufacturing liquid crystal (LC) displays, To determine the amount of LC material used in the aforementioned LC display, Based on the LC material and the amount of the LC material, A silane material to be mixed with the LC material, and The amount of silane material to be mixed with the LC material To decide, Mixing the aforementioned amount of silane material with the aforementioned amount of LC material to produce an LC mixture, and The LC mixture in contact with the display substrate is heat-treated to bond at least a portion of the silane material to one or more surfaces of the display substrate, so that the silane material acts as a surfactant. Methods that include...

2. The method according to claim 1, Determining the amount of the silane material to be mixed with the LC material, To determine the amount of the silane material that constitutes at least 0.8% by weight of the LC mixture. Methods that include...

3. The method according to claim 2, Determining the amount of the silane material to be mixed with the LC material, To determine the amount of the silane material comprising 0.8% by weight and 1.2% by weight of the LC mixture. Methods that include...

4. The method according to claim 2, Determining the amount of the silane material to be mixed with the LC material, The amount of silane material that may bond to one or more substrate surfaces during heat treatment is determined based at least partially on the display substrate. Methods that include...

5. The method according to claim 2, The heat treatment of the LC mixture includes calcining the LC mixture at a temperature of 105°C to 115°C for at least 50 minutes. method.

6. The method according to claim 2, The silane material comprises a silane molecule having one or more silane pendant groups and an alkyl chain containing one or more carbon atoms. method.

7. The method according to claim 2, The silane material is n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxylsilane, Octadecidimethyl(3-trimethoxysilylpropyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane Methods that include...

8. The method according to claim 7, The silane material is n-octadecyldimethylmethoxysilane. method.

9. The method according to claim 7, The silane material is n-octadecylmethyldimethoxysilane. method.

10. The method according to claim 7, The silane material is n-octadecyltrimethoxysilane. method.

11. The method according to claim 7, The silane material is n-octadecylmethyldiethoxysilane. method.

12. The method according to claim 7, The silane material is n-octadecyltriethoxylsilane. method.

13. The method according to claim 7, The silane material is octadecidimethyl(3-trimethoxysilylpropyl)ammonium chloride. method.

14. The method according to claim 2, The LC material includes a nematic LC material or a chiral nematic LC material having negative dielectric anisotropy. The LC display includes a spatial light modulator configured to operate in vertical orientation nematic (VAN) display mode. method.

15. The method according to claim 2, The LC material includes a nematic LC material or a chiral nematic LC material having negative dielectric anisotropy. The LC display includes a spatial light modulator configured to operate in a twisted vertical orientation nematic (TVAN) display mode. method.

16. A liquid crystal (LC) mixture for use in LC displays, A certain amount of LC material, and The LC material and a certain amount of silane material determined based on the amount of the LC material. A liquid crystal (LC) mixture containing the above.

17. The LC mixture according to claim 16, The amount of the silane material is at least 0.8% by weight of the LC mixture. LC mixture.

18. The LC mixture according to claim 17, The amount of the silane material is between 0.8% and 1.2% by weight of the LC mixture. LC mixture.

19. The LC mixture according to claim 17, The silane material comprises a silane molecule having one or more silane pendant groups and an alkyl chain containing one or more carbon atoms. LC mixture.

20. The LC mixture according to claim 17, The silane material mentioned above, n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxylsilane, Octadecidimethyl(3-trimethoxysilylpropyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane An LC mixture containing the above.

21. The LC mixture according to claim 17, The LC material includes a nematic LC material or a chiral nematic LC material having negative dielectric anisotropy. The LC display includes a spatial light modulator configured to operate in a vertically aligned nematic (VAN) display mode or a twisted vertically aligned nematic (TVAN) display mode. LC mixture.

22. Liquid crystal (LC) display, Nematic LC materials or chiral LC materials having negative dielectric anisotropy configured to operate in vertical orientation nematic (VAN) display mode or torsion vertical orientation nematic (TVAN) display mode, A display substrate configured to include the nematic LC material or chiral nematic LC material, and The display substrate includes a silane material bonded to one or more surfaces and disposed between the one or more surfaces and the nematic LC material or chiral nematic LC material, wherein the silane material is The amount of the silane material and the amount of the nematic LC material or chiral nematic LC material are present in an amount such that the ratio is between 0.8:99.2 and 1.2:98.

8. n-octadecyldimethylmethoxysilane, n-octadecylmethyldimethoxysilane, n-octadecyltrimethoxysilane, n-octadecylmethyldiethoxysilane, n-octadecyltriethoxylsilane, Octadecidimethyl(3-trimethoxysilylpropyl)ammonium chloride, 1,2-bis(trimethoxysilyl)decane, or 1-n-decyl-1,1,3,3,3-pentamethoxy-1,3-disilapropane Liquid crystal (LC) displays, including those containing liquid crystal.

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