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This study presents the development of ultra‐thin azo‐dye polarizers, notable for their minimal thickness (100‐200 nm) and superior optical performance, with polarization efficiency exceeding 99.9%, extinction ratios above 4000, transmittance over 45.3%, and dichoric ratio over 100. Utilizing cost‐effective solution‐processing methods, we fabricate these high‐performance polarizers and determine optimal experimental conditions for peak efficacy. Our research includes comprehensive Scanning Electron Microscopy analyses to understand the microstructural properties of these azo‐dye thin film polarizers, contributing significantly to the field of advanced display technologies. [ABSTRACT FROM AUTHOR]

A new ODF machine for high‐viscosity liquid crystals (LCs) is successfully constructed and tested using ferroelectric liquid crystals (FLCs). Innovatively, heating over 100°C, filling FLC in a vacuum, and sealing can automatically be done in one reaction pot. No glue leakage exists in the FLC samples. Good alignment without defect and electro‐optic (EO) performance are achieved. The response time is 33 μs, and relaxation time is 27 μs. Contrast Ratio (CR)=10000:1 (@ 632 nm). This is one of the critical steps towards the commercialization of FLC‐based displays and optoelectronic devices. [ABSTRACT FROM AUTHOR]

We achieve high‐framerate (< 100 μs) high‐contrast‐ratio ferroelectric liquid crystal displays (FLCD) on Gen 4.5. Innovatively, a new polyimide (PI) that is suitable for ferroelectric liquid crystal (FLC) alignment is synthesized and tested on the production line. It replaces Nylon 6 (N6), which was the barrier to the commercialization of FLCD. Moreover, a new FLC is synthesized to match requirements in mass production. Additionally, various materials were studied to investigate the surface energy and relative performance. It is not only proof of the feasibility on the production line, but also a significant step towards the commercialization of field‐sequential‐color high‐resolution FLCDs. [ABSTRACT FROM AUTHOR]

This study presents the characterization and performance evaluation of photo‐aligned azo‐dye thin‐film polarizers, highlighting their ultra‐thin profiles and superior optical functionalities. Utilizing cost‐effective solution‐processing methods, these high‐efficiency polarizers were developed, with the research pinpointing optimal experimental conditions for peak performance. [ABSTRACT FROM AUTHOR]

Vertically Aligned LCD is one of the most widely used optical modes in LCD TV and mobile devices. It is also a very important category of passive LC displays used in Automobiles. It has the advantages of perfect dark state and very high contrast ratio for normal viewing. However, single domain VA LCD has the intrinsic issue of dead zone (contrast vanishing zone) in certain viewing direction in the voltage‐on state, which seriously limits its viewing angle performance. Recently, the State Key Laboratory on Advanced Displays and Optoelectronics Technologies of the Hong Kong University of Science and Technology has developed an easy‐to‐apply multi‐domain VA LCD technology that can be readily implemented in LCD factories without major investment and change in current production process. [ABSTRACT FROM AUTHOR]

Optimized ODF machine for large scale display filled by ferroelectric liquid crystals (FLCs) is developed. Fast FLC filling at high temperature (100°C) in the vacuum, and sealing can automatically be done in one reaction pot. An uniform cell with good alignment quality and electro‐optical (E&O) performance are achieved which shows high contrast ratio (CR) =10000 :1 and a fast response time (33 μs) at room temperature, respectively. The realized FLC cell by ODF indicates that there are no mass production barriers for large scale FLC display. [ABSTRACT FROM AUTHOR]

A successful test of Ferroelectric Liquid Crystal Displays (FLCD) on Gen 4.5 is realized in this paper. A new polyimide (PI) that can replace Nylon 6 (N6) is synthesized and tested on the production line. This used to be the barrier in the commercialization of FLCD. Apart from that, a new FLC for mass production is synthesized. To investigate the surface energy and relative performance, various materials are compared. This proof of the feasibility on the production line is a significant step towards the commercialization of field‐sequential‐color high‐resolution FLCDs. [ABSTRACT FROM AUTHOR]

As amorphous oxide semiconductors (AOSs) are hotly pursued for advanced displays, flexible electronics, optoelectronics, and neuromorphic systems, the AOS Schottky barrier diodes (SBDs) have been tried only using the mainstream amorphous InGaZnO (a‐IGZO) and the conservative bottom‐anode structure. To deepen the study on AOS SBDs, the more challenging top‐anode SBD is developed in this work using a versatile but vulnerable AOS, amorphous InZnO (a‐IZO). Unsurprisingly, the Schottky interface defects are seriously increased by the top‐anode process and the defective a‐IZO, which cannot be effectively passivated using the incumbent oxidizing treatments. The hydrogenation is proposed to considerably suppress these annoying interface defects and thus correspondingly reduces the large leakage current, while the hydrogen doping easily deteriorates a‐IGZO SBD. The underlying mechanism of such distinction is revealed to be the tricky interactions between defect and hydrogen in AOSs. Based on the sophisticated utilization of such defect‐hydrogen interplay, the a‐IZO/a‐IGZO stack is hydrogenated together to simultaneously realize a high‐conductivity bulk and low‐defect interface, noticeably enhancing the performance metrics. Such top‐anode SBD based on hydrogenated multilayer AOSs successfully blazes a novel evolution path for AOS SBDs. [ABSTRACT FROM AUTHOR]

Electronic ink (E‐ink) displays have become increasingly popular in e‐books due to their paper‐like appearance, readability in direct sunlight, low power consumption, and flexible sizing. However, the slow switching speed of bistable LCDs and E‐ink limits their ability to play animations. This paper proposes a novel method for fabricating fast‐ switching bistable liquid crystal displays capable of playing animations. The research is based on a new type of bistable LCD technology that achieves lower driving voltages than existing E‐ink displays. The research team has significant experience developing bistable displays and has invented many new technologies in their laboratory. The proposed technology combines the benefits of bistable displays with the ability to play animations, a significant advancement in display technology. [ABSTRACT FROM AUTHOR]

This work demonstrates a high‐performance in‐cell polarizer adopting photo‐aligned azobenzene dyes. On the strength of the multilayered design, a simple fabrication process has been developed to assemble an in‐cell polarizer. We have achieved a broadband dichroic ratio after the long‐term stability test. Meanwhile, the cell with the proposed in‐cell polarizer can be driven regularly without a voltage boost, which renders excellent practicability in liquid crystal display technologies. The structure, fabrication process, and properties of the in‐cell polarizer in TN‐LCD are thoroughly discussed. [ABSTRACT FROM AUTHOR]

Azo dyes are valuable functional materials due to their sensitive response to and effective modulation of polarized light. It is essential to find out not only the optical anisotropy but also the complex refractive index of azo dye materials for photonics applications. We report here such measurements of highly ordered photoaligned azo dye films. The film has an apparent dichroic ratio of about 60. We model the photoaligned azo dye film systems using the Berreman transfer matrix. By means of regression fitting of the polarization dependent transmittance and reflectance data, we were able to determine the complex refractive indices of the aligned film at the wavelength range of 400–1000 nm. This material is found to have exceptionally large optical birefringence (Δn ∼ 0.75 at 632.5 nm and Δn ∼ 0.48 at 850.6 nm). The aligned azo dye film is valuable to applications such as coatable polarizers and optical modulation devices. [ABSTRACT FROM AUTHOR]

The most common electronic paper technology is E‐ink, which enables many novel applications such as e‐readers, watches and electronic shelf labels. However, due to the TFT backplane driving and complex production processes, the cost of this technology is high, which limits its popularity. Recently, a low‐cost π‐bistable twist nematic (π‐BTN) liquid crystal display with a high pretilt angle is proposed. It has the same structure and production method as an ordinary liquid crystal display. Passive driving enables the manufacture of high‐resolution bistable displays without the use of thin‐film transistors. Compared with the current bistable twist nematic display technology, the high pretilt angles structure helps to achieve a lowvoltage and fast‐respond bistable display. This wide viewing angle, high contrast and TFT‐free display is a promising candidate for flexible displays. [ABSTRACT FROM AUTHOR]

This work focuses on developing a solution‐based ultra‐thin polarizer for liquid crystal displays, utilizing dichroic azo dye AD1 as the key material. The produced AD1 polarizer exhibits excellent optical performance with a dichroic ratio of over 95. The film thickness is less than 200nm. Furthermore, a TN LCD with an incell polarizer is demonstrated. This technology shows excellent prospects for developing high‐performance, coatable polarizers with scalability and lower‐cost manufacturing potential. [ABSTRACT FROM AUTHOR]

Ultrathin (<200nm) azo dye polarizing film with a high dichroic ratio (over 150) is developed by photo‐alignment methods. Polarizing film prepared by solution‐based process (post‐ photoalignment) and evaporation (in‐situ photo‐alignment) with a family of azo dye materials with slightly different molecular structures is explored. We study the photostability of these azo‐dye films against polarized light. Methods and factors of getting high dichroic ratio and high photostability polarizing films are discussed. [ABSTRACT FROM AUTHOR]

An approach to developing a thin‐film polarizer with high polarization efficiency in liquid crystal cells is presented. The in‐cell polarizer facilitates the realization of novel color‐conversion liquid crystal displays, where advanced quantum color‐converters are used as photoluminescent color filter arrays. We experimentally demonstrated using azo‐dye‐based embedded polarizers for color‐conversion liquid crystal displays for the first time. We systematically designed the device structure and fabrication process. The display is color parallax free and can be driven at regular conditions with good contrast. [ABSTRACT FROM AUTHOR]

Owing to the angular dependent birefringence, liquid crystal displays are subject to viewing angle issues. Various wide viewing angle LCD technologies have been developed to solve the problem. The concept of photoluminescent LCD (PLLCD) as a promising solution for wide viewing LCD has been proposed more than two decades ago. Recently quantum dot photo‐luminescent material has been applied in LCD TV in the form of backlight color enhanced film (QDEF). More recently quantum dot emissive color converter which essentially changes the LCD to becoming an emissive display is also proposed. Here we report our attempt to include a photo‐luminescent film in front of a conventional LCD to enhance the viewing angle and the challenges encountered. [ABSTRACT FROM AUTHOR]

PDLC based smart window is currently the choice of switchable privacy window widely used in hotels and conference rooms. The ability of image hiding behind the window is now represented by the percentage haziness according to ASTM D1003 (or equivalent GB2410‐2008). The ASTM D1003 is originally designed for measuring wide angle light scattering with haze value less than 30%. This is not quite suitable for high haze level PDLC measurement. In this article, we introduce a narrow angle scattering (NAS) method that can better correlate the image hiding level and the measurement readings. An image hiding factor (IHF) is also introduced by making use of the narrow angle scattering measurement results. [ABSTRACT FROM AUTHOR]

Stable ferroelectric liquid crystal (FLC) elements have been realised by optically stabilised alignment film and thermally stabilised alignment film. The two methods of fabricated FLC elements have been explored for different aspects, namely alignment quality, electro-optical response and their possibility for complicate aligning patterns such as grating and Pancharatnam–Berry lens. They are compared based on different requirements of applications. With these two approaches, we are able to produce various types of FLC photonic and display devices with good photostability. [ABSTRACT FROM AUTHOR]

Photoalignment technology has been proven useful in the patterned alignment display industry. For large area display, most of the available in‐plane switching (IPS) mode TVs or panels use photoalignment technology. Not only it allows free pattern alignment direction to the liquid crystal compared to the conventional rubbed polyimide, but also it provides high yield and stability. However, the cost of the photoalignment technology could be very high. The materials often require polarized deep UV irradiation with a finite dosage to generate pretilt angles. Due to the improper control of rubbing on the alignment layer, the low yield rate problem still exists in the passive LCD world, especially for vertical photoalignment LCDs. It would be ineffective to improve the yield rate problem with this technology. Furthermore, the required materials are not common in the market. In view of the situation, a Vertical Alignment (VA) surface by non‐polarized LED light irradiation with a large wavelength is proposed and demonstrated in this paper. The cost of the LED exposure equipment is relatively more affordable. In a series of factory pilot runs on the proposed alignment characteristics, it shows comparable result to conventional polyimides in terms of performance. It achieves a stable and uniform pretilt angle, with high anchoring energy and fast response time. To conclude, the proposed robust alignment layer could benefit the industry with a better performance at low cost. [ABSTRACT FROM AUTHOR]

The most common electronic paper technology is E‐ink, which enables many novel applications such as e‐readers, watches and electronic shelf labels. However, due to the TFT backplane driving and complex production processes, the cost of this technology is high, which limits its popularity. Recently, a low‐cost π‐bistable twist nematic (π‐BTN) liquid crystal display with a high pretilt angle is proposed. It has the same structure and production method as an ordinary liquid crystal display. Passive driving enables the manufacture of high‐resolution bistable displays without the use of thin‐film transistors. Compared with the current bistable twist nematic display technology, the high pretilt angles structure helps to achieve a low‐voltage and fast‐respond bistable display. This wide viewing angle, high contrast and TFT‐free display is a promising candidate for flexible displays. [ABSTRACT FROM AUTHOR]

We report a method of obtaining controllable spatially varying liquid crystal pretilt angles using a stacked alignment layer. The stacked alignment layer consists of nano-domains of horizontal and vertical alignment materials. The pretilt angle is controlled by varying the domain ratio of the two layers. By using photoalignment material as the top layer, the pretilt angle can be controlled by varying the UV light dosage. A spatially variable UV light beam can be used to control the pretilt angle spatially. An electrically tunable-focus liquid crystal lens is obtained using this method. [ABSTRACT FROM AUTHOR]

The Polymer Network Liquid Crystal (PNLC) cell we fabricated is operating in a reverse mode of voltage‐off transparent state. It is found that when we apply voltage to the PNLC cells, the transmitted light color changed gradually and finally became a bit blue. This effect is not found in Polymer Dispersed LC (PDLC) window. The wavelength dependent transmittance voltage curves are reported and we will try to explain this effect by applying the anomalous diffraction theory. [ABSTRACT FROM AUTHOR]

Photoalignment is one of the best candidates of the proven market for multi domain display. It allows nearly free pattern to the liquid crystal alignment direction compared to the conventional rubbed polyimide. Most of the available photoalignment materials require polarized deep UV irradiation with a finite dosage. With the consideration of the current limitation with such a small working window, a vertical photoalignment surface by non‐polarized LED light irradiation with large wavelength is proposed and demonstrated. The alignment direction of proposed surface is generated by the inclined non‐polarized light. The measurement results show the alignment properties of this proposed alignment surface are comparable to conventional polyimide. It has stable and uniform pretilt angle, high polar anchoring energy and fast response time. As a result, the proposed alignment layer is robust and especially suitable for large‐area liquid crystal displays which require high performance with stable pretilt angles and multi‐domain purposes. [ABSTRACT FROM AUTHOR]

In this article, we present a high performance smart window via micro‐domains manipulation on the alignment surface, which dramatically enhances the power‐on haze by 48%. Large‐scale window with ultra‐hazy state switching in less than 3.5 ms is demonstrated. [ABSTRACT FROM AUTHOR]

Smart windows which switch between transparent and scattering states can be used not only as privacy window in buildings and cars, but also as information displays, and motorcycle helmet visors. Here, we have proposed a reverse mode polymer-stabilised liquid crystals (PSLCs) smart window based on inhomogeneous alignment surface, which greatly enhances the haze by 42% when compared to device without inhomogeneity treatment. A 100-cm2 window that switches between the power-off clear state (~4% haze) and a power-on scattering state (64% haze at 15 V) in less than 3.5 ms is demonstrated. Since no high-temperature treatment (< 80°C) is involved in device fabrication, further development on plastic films is feasible. [ABSTRACT FROM AUTHOR]

Smart windows are attractive because of their numerous advantages such as elegance in construction design and energy conservation. Smart windows with variable transmission are especially desirable for obvious reasons. The simplest way to make a variable transmission smart window is to use two patterned polarizers, and control the transmission by changing the relative position of the two polarizers. We have demonstrated a high‐dichroic‐ratio polarizer by photoalignment and proposed a simple one‐step photo‐copy method to realize a continuous axis varying polarizer. The patterned polarizer shows high optical performance, and its thickness is as thin as 100 nm, which is favorable in practical window applications. [ABSTRACT FROM AUTHOR]

A front polarizer‐free optically rewritable (ORW) liquid crystal displays (LCDs) has been made via a hybrid alignment configuration with dye‐doped LCs. The hybrid structure consists of one optically active planar and one optically passive homeotropic alignment layer. The rewritability of the device is achieved by photo‐ reorienting the azo dye molecules in the active planar alignment layer. The dye doped in LCs function as a polarizer by following the LCs alignment via a guest‐host effect so that the front polarizer can be eliminated. This makes the device more compact and easier to operate for image erasing and rewriting. The image rewriting time only requires ~9.0s, which is determined by the exposure energy and LC parameters. The hybrid‐mode dye‐doped optically rewritable (DDORW) LCD devices could find applications in E‐paper, transparent display and various photonics devices. [ABSTRACT FROM AUTHOR]

A novel azo dye stabilization method was presented that only requires single-shot UV light exposure. The proposed photoalignment layer offers highly acceptable thermal and photo-stability, as well as low pre-tilt angle (0.2°) and low image sticking (1.01). Also, high VHR (99%) and low RDC (<10mV) comparable to that of PI rubbing have been achieved. Furthermore, the ability of multi-domain alignment has been demonstrated that shows a great potential in a wide range of electro-optical devices. [ABSTRACT FROM AUTHOR]

In this article, a photoalignment layer, based on the azo dye and liquid crystal polymer (LCP) composite is proposed. The alignment layer offers easy processing and high photo and thermal stabilities. The high VHR (99.1%) and low RDC (30mV) have been achieved that is comparable with the conventional PI rubbing alignment layer. The proposed alignment layer shows low pre-tilt angle and small image sticking which is highly desirable for IPS display. Furthermore, the ability of multi-domain alignment has been demonstrated that shows a great potential to find applications in a range of electro-optical devices particularly those requiring in-plane LC director modulations. [ABSTRACT FROM AUTHOR]

We employed the technique of photoalignment to fabricate polarizers using dichroic dyes and liquid crystal polymers. By varying the polarization direction of the UV/blue light, polarizers with spatially varying absorption axis were made. Such polarizers have many applications. As an example, we showed how mechanical translation of two such polarizers can be used as a variable transmission smart window, in which no electric power is needed. In this work, a 5cm x 5cm window device was made and demonstrated with very good bright and dark states. [ABSTRACT FROM AUTHOR]

By recent progress in electrically suppressed helix (ESH) ferroelectric liquid crystal (FLC) mode, a novel pixel design employing pulse width modulated (PWM) grayscale scheme, focusing on TFT flat panel display applications is proposed. Such design has a 3T1C structure, which is compact enough to preserve reasonable pixel aperture in practice. Incorporating an innovative driving scheme, the proposed architecture successfully demonstrates a fully digital and TFT compatible AMFLC pixel architecture, possessing uniform and continuous grayscale. This invention is essential in obtaining ultra-fast high quality liquid crystal displays, and particularly useful for field-sequential-color direct-view flat-panel display. [ABSTRACT FROM AUTHOR]

A photo-stable azo dye photoalignment surface for liquid crystal is proposed and demonstrated. The alignment surface has a structure of stacking a thin photo-polymerisable liquid crystal polymer on top of an azo dye photoalignment layer. The liquid crystal polymer acts as a passivation layer for the azo dye alignment layer. The alignment direction of the azo dye cannot be rewritten once the liquid crystal polymer is polymerized. Hence, the synthetic alignment surface is robust, highly reproducible and has excellent stability. In addition, measurement results show the alignment properties of this synthetic alignment surface are comparable to conventional polyimide. As a result, the proposed alignment layer is suitable for in plane switching liquid crystal display which requires high anchoring energy and very small residual direct current. [ABSTRACT FROM AUTHOR]

We report a method of fabricating a nano-sized stack alignment layer. The stacked alignment layer consists of nano-domains of vertical and planar alignment materials. Experiments reveal that photoalignment thin film can undergo dewetting and form discrete nano-sized domains. Such self-organized structure creates a discontinuous layer stacked on top of a continuous layer and hence produces an inhomogeneous alignment surface. With two or more different principle alignment directions, this new alignment layer is capable of producing multiple pretilt and azimuth angle domains on a single substrate. [ABSTRACT FROM AUTHOR]

A novel nano-structured photoalignment surface is proposed and demonstrated. Such alignment surface has bistable azimuthal alignment directions for the liquid crystal molecules. The new alignment surface has a structure of stacking a photo-polymerizable photoalignment polymer on top of a nano-sized groove surface. The photoalignment polymer and groove surface have different azimuthal alignment directions but the same azimuthal anchoring energies. The fabrication of the nano-sized groove is based on nano-imprint lithography. Hence, the size and depth are controllable, where no random process is involved. The alignment surface is robust, stable, reliable, reproducible and suitable for mass manufacturing. Such alignment surface can be applied to fabricate a π/2 bistable twisted nematic (π/2-BTN) display which has better optical performances than the traditional π-BTN display. [ABSTRACT FROM AUTHOR]

A novel discontinuous photoalignment surface with nano-domains for liquid crystal is developed. The formation of the discontinuous structure is created by self-organized dewetting, which is regarded as one of the most promising bottom-up approaches to fabricate nano-structure. Different dewetting conditions, such as surface roughness, thickness and viscosity, have been investigated. Such discontinuous photoalignment layer can be fabricated on top of another continuous alignment layer to form a new kind of heterogeneous nano-structured alignment surface - stacked alignment layers. This heterogeneous alignment surface can be used to produce arbitrary pretilt angles for the liquid crystal display. Simulation model has been built to understand the dewetting mechanism. Experiments using photo-aligned and photo-polymerisable polymer have been done to verify the dewetting theory. The produced stacked alignment layers are proved to be robust. Moreover, the dewetting processing is a fully controllable process and is compatible with existing manufacturing techniques. [ABSTRACT FROM AUTHOR]

A fast π bistable twist nematic (π-BTN) liquid crystal display controlled by nucleation process is developed. The nucleation induced by the patterned spacer inside the cell. The response time is fast and it depends on the density of patterned spacer. [ABSTRACT FROM AUTHOR]

A novel kind of nano-structured alignment surface is proposed and demonstrated. Such alignment surface has bistable azimuthal alignment directions for liquid crystal molecules. The new alignment surface has a structure of stacking a photo-aligned polymer on top of a nano-sized groove surface with different azimuthal alignment directions. The fabrication of the nano-sized groove is based on nano-imprint lithography. Hence, the size and depth are fixed and controllable; in addition, no random process is involved. The alignment surface is robust, highly reproducible and suitable for mass manufacturing. Such alignment surface can be applied to fabricate π/2 bistable twisted nematic (π/2-BTN) display which has better optical performances than the traditional π-BTN display. [ABSTRACT FROM AUTHOR]

A stereoscopic three-dimensional (3D) system using a polarization rotator is proposed. The polarization rotator converts the polarizations of different eyes' images in temporal multiplexing. A novel fast nematic liquid crystal mode is also proposed. The new liquid crystal mode has fast response time and high contrast; hence it is a good candidate for polarization rotator. The proposed 3D system utilizes only passive polarized glasses, which are more convenient, light weight and low cost. In addition, the polarization rotator can be applied to current 2D displays and become 3D capable display. [ABSTRACT FROM AUTHOR]

A new kind of nano-structured alignment surface is proposed and demonstrated. Such alignment surface is capable of generating arbitrary pretilt angles for liquid crystal. The new alignment surface is based on nano-imprinting and plasma etching. The domain sizes are fixed and controllable; in addition, no random process is involved. The alignment surface is robust and highly reproducible. Moreover, the processing window is maximized and suitable for mass manufacturing. [ABSTRACT FROM AUTHOR]

In this paper, a TFT based polarization-controllable lightprinter for optically rewritable (ORW) liquid crystal displays (LCDs) is proposed. Experimental results with gray scale images are also presented. The light-printer consists of a vertically aligned nematic (VAN) mono-color TFT LCD as a polarization controlling unit. 420nm LED light source with Fresnel lens forms the projection unit. With this two-dimensional controlling unit, this light-printer can transfer content to a large-area ORW LCD panel easily. [ABSTRACT FROM AUTHOR]

Recently the in-plane switching (IPS) has been heavily exploited in particular for high-resolution mobile displays. The IPS displays offer good optical quality, however, the complex fabrication and manufacturing cost offers several limitations for their application. On the other hand, electrically suppressed helix ferroelectric liquid crystals (ESHFLC's) because of their intrinsic in-plane switching offer better solutions with simpler and cheaper fabrication for high-resolution displays. In this article, the ESHFLC's with fast response time (˜10µs), high contrast ratio (˜ 10k: 1) with low driving voltage (2˜5V/µm) has been achieved through photo alignment technology with acceptable shock stability and without natural diffraction. The ESHFLC's provide good optical quality with simpler fabrication procedures and therefore could secure application for high-resolution displays. [ABSTRACT FROM AUTHOR]