Liquid Crystal Display Research Articles

Light-guided dynamic phantom to mimic microvasculature for biomedical applications: an exploration for pulse oximeter.

Dynamic phantoms capable of changing optical properties by control are essential for standardizing and calibrating spectroscopy systems such as the pulse oximeter. However, current liquid dynamic phantoms containing human blood have a short shelf life and require complex experimental setups. Some solid dynamic phantoms are influenced by the angular-dependent performance of the liquid crystal display (LCD), some have a low spatial resolution, and some have slow control of optical properties. We aimed to develop a solid dynamic phantom, which can overcome these obstacles by changing the optical properties rapidly and generating dynamic biological signals. The absorption properties of the phantom can be controlled in real time by modulating an LCD. A light guide was employed to avoid the angular-dependent performance of the LCD by isolating the scattering top-layer tissue-mimicking silicone phantom from the LCD. The dynamic phantom was characterized at 940, 660, 530, and 455nm to create a lookup table. Photoplethysmography signals of different heart rates from 80 to 120 beats per minute were synthesized, and oxygen saturation levels at 86%, 90%, 95%, and 100% were generated at multiple wavelengths. The design, characterization, and potential applications of the dynamic phantom have been presented. This dynamic phantom can simulate various biological signals by applying corresponding modulation signals and has the potential to calibrate and validate pulse oximeter, imaging, and spectroscopy systems.

Liquid Crystal Displays With Printed Carbon-Based Recyclable Transistor Backplanes

Liquid Crystal Displays With Printed Carbon-Based Recyclable Transistor Backplanes

DACA-Net: Detail-aware network with contrast attention for locating liquid crystal display defects

Liquid crystal display (LCD) defects are characterized by their tiny size and low contrast, making it difficult to accurately categorize and quantify these defects during inspection. To overcome these challenges, we proposed a detail-aware network with contrast attention (DACA-Net). First, we constructed a low-level semantic refinement (LSR) module, which restructures the cross stage partial (CSP) structure of the backbone network, enhancing the detail-aware capability for tiny objects. Second, we designed a low-level semantic deep fusion (LSDF) module that integrates detailed semantic information during feature fusion, effectively mitigating the loss of tiny objects information post deep convolution. Third, we proposed a dual-focus contrast enhancement attention (DFCEA) module, which alleviates the insufficient spatial semantic information of low-contrast objects, thereby enhancing the detection of defects under low-contrast background. Moreover, we present a representative LCD light Defect (LCDLD) dataset to address the lack of dataset in this field. We validated our model using the LCDLD and PKU-Market-Phone datasets and tested its generalizability with the PKU-Market-PCB dataset. DACA-Net achieved mean average precision (mAP) scores of 96.7%, 98.5%, and 97.1% on these datasets, respectively, surpassing 16 state-of-the-art object and defect detection models.

Strength and stiffness anisotropy of 3D-printed coarse root analogues for small-scale physical modelling

Plant root–soil mechanical interaction in the application of soil bioengineering such as tree and slope stability has been investigated by way of centrifuge modelling, utilising root analogues to replicate vegetated soils. Three-dimensional (3D) printing can be used to model complex root architecture, but the nature of the layer-upon-layer printing process may lead to printed parts of differing tensile behaviour depending on orientation and, consequently, unrealistic simulation of root mechanical reinforcement. This study aimed to assess the strength and stiffness anisotropy of straight root analogues built at varying orientations by way of three different 3D printing methods and compare the measured properties with those of real roots. The tensile strength ratios between horizontal- and vertical-printed samples were up to 3·90, 1·27 and 2·57 for fused deposition modelling (FDM), liquid-crystal display and PolyJet methods, respectively. Stiffness anisotropy was also more significant in FDM. The relatively higher anisotropy in FDM-printed samples could overestimate the strength and stiffness of most roots in a hypothetical heart-shaped root system, depending on the diameter distribution. Such a physical model may be improved by using 45° inclined PolyJet-printed rods.

Design and Evaluation of Two Proposed Hybrid FCC-BCC Lattice Structures for Enhanced Mechanical Performance

Lattice structures are an innovative solution to increase the strength-to-weight ratio of a structure. In this study, two polymeric hybrid lattice structures—"FRB" (a heterogenous structure which is indeed a BCC structure reinforced by FCC unit cells dispersed in a way to form a chessboard pattern in each layer) and the "Multifunctional" (a homogenous structure whose unit cells are a combination of FCC and BCC unit cells where their central nodes are connected)—are proposed, fabricated via liquid crystal display 3D printing technique, and their mechanical characteristics are evaluated under quasi-static loading, experimentally and numerically. The results indicate a 15.71% increase in compressive strength and a 103.75% improvement in volumetric energy absorption for the FRB structure compared to BCC. The Multifunctional structure revealed a 74.30% increase in compressive strength along with a 111.30% improvement in volumetric energy absorption compared to BCC, though it exhibited a 13.33% decrease in specific energy absorption compared to the FCC structure. Both the proposed designs have merits; the FRB structure suitable for lightweight energy absorption and the Multifunctional structure appropriate for high load-bearing applications where the overall weight is not the primary concern.

Water Quality Monitoring System Based on IoT

Water quality is a crucial factor in public health, agriculture, and industry, and it has become increasingly important to monitor and maintain it effectively. Traditional water quality testing methods are often time-consuming, require manual sampling, and can involve complex equipment and processes, which may not be suitable for continuous monitoring. This project, titled "IoT- Based Water Quality Monitoring System," aims to create a real-time, automated solution that continuously monitors essential water quality parameters, namely pH, Total Dissolved Solids (TDS), and turbidity, using IoT technology. The system utilizes a suite of sensors connected to an ESP32 microcontroller to capture data for each of these parameters. The pH sensor monitors acidity or alkalinity, the TDS sensor measures the total amount of dissolved solids to determine purity, and the turbidity sensor assesses the clarity of water, detecting particulate matter that may indicate contamination.The gathered data is displayed locally on a 16x2 LCD screen, providing instant access to real-time readings. Additionally, the ESP32 microcontroller is connected to the Blynk cloud platform, where data is transmitted and stored, enabling remote access and monitoring of water quality. Users can access the data from any location via the Blynk mobile application, making it highly versatile and accessible. By using the Blynk cloud, the system provides valuable flexibility for applications in remote or unattended environments, where it may not be practical to monitor water quality manually.The IoT-based water quality monitoring system holds significant potential for application across a range of sectors. In drinking water supply systems, it allows for continuous monitoring, which helps maintain safety standards by identifying variations in water quality immediately. For agricultural irrigation, the system ensures that crops receive water that meets quality standards, contributing to better crop health and yield. Industrial applications, where specific water standards are often required for processes, can also benefit from the system's ability to detect deviations in water quality.In conclusion, this IoT-enabled water quality monitoring system provides an efficient, real-time, and remotely accessible solution for monitoring water parameters. With the integration of IoT, it presents a cost-effective approach to water management, enhancing responsiveness to quality changes and contributing to health and environmental sustainability. This system not only reduces the reliance on periodic manual testing but also enables proactive water quality management, thus supporting the sustainability of natural resources in a variety of applications.

IoT Assistive Technology for People with Disabilities

This project is dedicated to developing a Smart Medication Alert System utilizing Arduino and a variety of hardware components designed to improve medication adherence, particularly for individuals with disabilities. The system combines visual, auditory, and display-based notifications through LEDs, a buzzer, and an LCD screen, making it accessible to users with visual impairments or those managing complex medication schedules. With real-time tracking and user-specific reminders, the system will prompt users about scheduled medication times, notify them of missed doses, and provide dosage instructions if necessary. By streamlining the medication-taking process and reducing the risk of missed doses or errors, this system aims to foster greater independence, enhance the user's quality of life, and ultimately support improved health outcomes for those requiring regular medications.

Preliminary Beneficiation Studies of Quartz Samples from the Northwest Territories, Canada

Three quartz-rich geologic materials—vein quartz from the Great Bear Magmatic Zone, massive quartz from the Nechalacho rare earth deposit, and quartz sands from the Chedabucto silica sand deposit along the shores of the Northern Arm of the Great Slave Lake, Northwest Territories of Canada—were evaluated for their amenability to physical beneficiation into high-purity quartz (HPQ). The samples were subjected to various treatment processes, including crushing, grinding, calcining and quenching, acid leaching, wet high-intensity magnetic separation (WHIMS), and reverse flotation. After treatment, both the core and sand quartz samples met the requirements for HPQ, making them suitable for use in the production of semiconductor filters, liquid crystal displays (LCDs), and optical glass. However, the Al-bearing impurity content in the vein quartz products remained relatively high, and most of these impurities were dispersed in the quartz lattice, requiring further processing to meet the purity standards for HPQ required by these industries.

Blue light irradiation-stirred washing high luminescence and highly stable CsPbBrI2 quantum dots modified with CaO for backlight display

Perovskite quantum dots (QDs) have become the star material for liquid crystal display (LCD). However, instability affects its practical application. Herein, CsPbBrI2 quantum dots (CsPbBrI2 QDs) with high quantum efficiency have been successfully precipitated in situ by adding CaO to the Li-Al-Si glass substrate. The photoluminescence quantum yield (PLQY) was adjusted from 64.5 % to 87.5 %. At the same time, we adopted a new strategy of blue light irradiation-stirred water washing. When blue light irradiation and stirred water washing interact synergistically, the naked CsPbBrI2 QDs detached from the glass surface, while smaller CsPbBrI2 QDs continued to grow. This process successfully resulted in CsPbBrI2 QDs with high luminescence intensity and high stability. Moreover, when exposed to 60 °C, 90 % relative humidity (RH), and 2000 nit blue light for 240 hours (h), the treated sample could retain 91.1 % of the original emission intensity. The color gamut of the prepared CsPbBrI2@CsPbBr3@glass@polystyrene (PS) light conversion film covered 122 % of the NTSC 1953 standard and 90 % of the Rec. 2020 standard. It provided great value for the commercialization of QDs in backlight display applications.

Development of a Light Intensity Monitoring System in Broiler Chicken Coops Based on Arduino IoT Cloud

The lighting system significantly influences the growth and productivity of broiler chickens, necessitating an efficient tool for monitoring light intensity in chicken coops. This study aims to design and develop an Arduino IoT Cloud-based light intensity monitoring system for broiler chicken coops. The system employs two BH1750 light sensors, positioned inside and outside the coop, to measure light intensity, which is then processed by an ESP32 microcontroller. The collected data is displayed on a 16x2 LCD screen and uploaded in real time to the Arduino IoT Cloud platform for remote monitoring. Testing conducted over a 6-hour period revealed that light intensity inside the coop remained stable at approximately 30 lux from 09:30 to 12:52, while the highest external light intensity reached 400 lux between 12:06 and 14:40, followed by a decrease after 14:50. These findings indicate that the system can assist farmers in timely actions, such as opening or closing coop curtains, through effective monitoring via the Arduino IoT Cloud platform.

Carbon dots induced homeotropic alignment in a negative dielectric nematic liquid crystal material

Abstract Recently, doping guest materials such as quantum dots (QDs) into liquid crystals (LCs) has been of great interest since their addition substantially enhances the properties of LC and opens new avenues for scientific advancement. Here, we report the induction of homeotropic alignment in cells without alignment layers of the negative dielectric nematic liquid crystal, N-(4-Methoxybenzylidene)-4-butylaniline (MBBA) by doping with carbon dots (CDs ∼2.8 ± 0.72 nm). The CDs-MBBA composites (CDs concentration: 0.002, 0.01, 0.03, 0.1 and 0.3 wt%) were investigated using optical polarising microscopy, electro-optical and dielectric techniques. Polarizing optical micrographs and voltage dependent optical transmission revealed the induced homeotropic alignment for all the composites under investigation. Interestingly, the least concentrated sample, 0.002 wt% exhibited partial homeotropic alignment. However, due to light leakage, the optical transmission value below threshold voltage was relatively higher than the rest of the composites. MBBA is a negative dielectric material, hence the application of a voltage across the cell was able to switch the alignment from a dark to a bright state for all composites. However, above a certain voltage (>threshold voltage), the bright state produced some instabilities. The value of dielectric permittivity was observed to decrease with increasing concentration, confirming the effect of CDs in producing homeotropic alignment in MBBA. Measurements as a function of temperature were conducted to examine the thermal stability of the induced alignment. The alignment was found to be stable throughout the nematic phase of MBBA. The induction of such alignment without conventional alignment (i.e., rubbing of polyimides) technique can be helpful in addressing the evolving display demands by making liquid crystal displays (LCDs) and other display devices cost effective.

Development And Testing of Arduino Based Autonomous Environmental Monitoring System

This paper presents the development of an Autonomous Environmental Monitoring System (AEMS) designed to track various environmental parameters. With the growing demand for autonomous monitoring systems in today’s modern era, we propose an Arduino-based real-time hardware solution to measure parameters such as flame, temperature, humidity, and distance. The system leverages advanced and cost-effective electronic sensors and hardware to monitor these environmental factors. We developed individual sensor modules for each parameter and integrated them into a unified multi-sensor system through sensor fusion. The collected data is then displayed on a 16 × 2 LCD module. The result is a fully functional autonomous monitoring system, tested under laboratory environmental conditions using a compact, handheld device.

Development of a Smart Lock System using QR Code Technology

A smart lock system refers to a modern security solution that enables users to remotely control access to their homes or businesses using a smart device such as smartphone, tablet, or computer. This paper presents the development of a smart lock system using Quick Response (QR) code technology to address the problem of insecurity, inconvenience, and inflexibility in access control. The proposed system eliminates the need for physical keys or complex authentication and verification methods. The system integrates an ESP8266 microcontroller, barcode scanner, 16x2 liquid-crystal display (LCD), solenoid lock, relay, and a 12V power supply. The system allows authorised users to generate unique QR codes representing their access credentials through a user-friendly interface. These QR codes are scanned by the system, which processes the codes, verifies access permissions via a central server and provides real-time feedback through the LCD. Upon successful verification, the system triggers a relay to control the solenoid lock, to grant or deny access. The implementation and testing of the smart lock system demonstrated successful operation. The performance indices include authentication speed, system reliability, accuracy and response time, which were evaluated and found to be satisfactory. The obtained results showed that the proposed system outperformed traditional methods such as keys, and fingerprint authentication, with an access speed of 2.00 seconds, which is significantly faster than the alternatives. Comparative analysis with existing access control techniques demonstrated the developed system's enhanced security features and user-friendly operation, making it applicable for residential, commercial, and industrial use. Additionally, the system's scalability and adaptability allow it to be customised for various environments, offering a versatile solution to diverse security challenges. This work contributes to the field of security technology by providing an efficient and scalable smart lock system with novel algorithms, which enhances the convenience, robustness of access control and seamless user experience.

Democratizing Access to Microfluidics: Rapid Prototyping of Open Microchannels with Low-Cost LCD 3D Printers.

Microfluidics offer user-friendly liquid handling for a range of biochemical applications. 3D printing microfluidics is rapid and cost-effective compared to conventional cleanroom fabrication. Typically, microfluidics are 3D printed using digital light projection (DLP) stereolithography (SLA), but many models in use are expensive (≥$10,000 USD), limiting widespread use. Recent liquid crystal display (LCD) technology advancements have provided inexpensive (<$500 USD) SLA 3D printers with sufficient pixel resolution for microfluidic applications. However, there are only a few demonstrations of microfluidic fabrication, limited validation of print fidelity, and no direct comparisons between LCD and DLP printers. We compared a 40 μm pixel DLP printer (∼$18,000 USD) with a 34.4 μm pixel LCD printer (<$380 USD). Consistent with prior work, we observed linear trends between designed and measured channel widths ≥4 pixels on both printers, so we calculated accuracy above this size threshold. Using a standard IPA-wash resin and optimized parameters for each printer, the average error between designed and measured widths was 2.11 ± 1.26% with the DLP printer and 15.4 ± 2.57% with the 34.4 μm LCD printer. Printing with optimized conditions for a low-cost water-wash resin designed for LCD-SLA printers resulted in an average error of 2.53 ± 0.94% with the 34.4 μm LCD printer and 5.35 ± 4.49% with a 22 μm LCD printer. We characterized additional parameters including surface roughness, channel perpendicularity, and light intensity uniformity, and as an application of LCD-printed devices, we demonstrated consistent flow rates in capillaric circuits for self-regulated and self-powered delivery of multiple liquids. LCD printers are an inexpensive alternative for fabricating microfluidics, with minimal differences in fidelity and accuracy compared with a 40X more expensive DLP printer.

Liquid Crystal Display with High Transmittance and Excellent Image Quality

High transmittance and excellent image quality are two crucial requirements for thin-film transistor liquid crystal displays (TFT-LCDs). This work presents a novel pixel structure utilizing a vertical alignment liquid crystal (VA-LC) to improve both transmittance and image quality. The new pixel structure, called TCL-pixel, features a unique transparent conducting layer (TCL) that constructs an electric field shielding layer and a large transparent storage capacitor, resulting in good stability and a large aperture ratio. The 55" 8K product incorporating the TCL-pixel achieves high transmittance (3.87%) and a high contrast ratio (5100:1), attributed to the large aperture ratio. Additionally, it exhibits negligible vertical cross talk (0.7%), low color cross talk (3‰), low horizontal cross talk (JND 2.3), and enhanced variable refresh rate performance, confirming its good stability. Furthermore, the TCL-pixel demonstrates an improved viewing angle (CESI 0.03：65°) due to the multi-domain alignment produced by the transparent conducting layer.

Font and background color combinations influence recognition efficiency: A novel method via primary color Euclidean distance and response surface analysis

The readability of human–computer interfaces impacts the users’ visual performance while using electronic devices, which gains inadequate attention. This situation is critical during high-stress conditions such as firefighting, where accurate and fast information processing is critical. This study addresses how font and background color combinations on Liquid Crystal displays (LCDs) affect recognition efficiency. A novel concept, primary color Euclidean distance (PCED), is introduced and testified under a repeated-measures experiment. Three factors were investigated: background color (black, white), font color (red, green, blue), and PCEDs. A total of 24 participants were recruited. Results demonstrate that color combinations with specific PCED values can substantially impact recognition efficiency. By using RSA, this study modelled the response time in a generalized mathematical model, which is response surface analysis. Results showed that blue font colors under a black background showed the longest response time. This study also explored the influence of physical stress on recognition efficiency, revealing a latency of about 100 ms across all color combinations. The findings offer a methodological advancement in understanding the effects of color combinations in digital displays, setting the stage for future research in diverse demographic and technological contexts, including mixed reality.

Internet based highly secure data transmission system in health care monitoring system

&lt;span&gt;The health care systems in our contemporary countries are advancing rapidly in terms of maturity and professionalism. In an effort to alleviate the current burden on the public health system and boost the popularity of regular health self-checks, this method has been developed for producing prediagnoses that are easier to use, quicker, and more accurate. To ascertain how well the heart is circulating oxygen throughout the body, a pulse test, a painless examination that measures an individual's degree of oxygen saturation, is used. It can be used to evaluate the state of any patient with a disease, particularly those with pulmonary problems. Diseases in these patients could need ongoing observation and care. Our system comes to the rescue in order to resolve this problem. This portable system is simple to use and may be taken anywhere by the subject. The internet of things (IoT) will update the pertinent parameters. This health monitoring system's controller is made up of an adaptor, a saturation of peripheral oxygen (SPO2 ) sensor (a blood oxygen meter), a temperature sensor, a heart rate sensor, a WiFi module, and a liquid crystal display (LCD).&lt;/span&gt;

Design of IoT-based monitoring system for temperature and dissolved oxygen levels in catfish aquaculture pond water

&lt;span&gt;One of the fish in Indonesian waters that has been successfully bred and cultivated is the catfish (Pangasius sp.). In catfish farming, there are several water quality factors that need to be considered, such as temperature and dissolved oxygen levels. Based on the existing description, it is very important to pay attention to the water quality of aquaculture ponds, especially temperature and dissolved oxygen levels for fish survival. This study aims to create an internet of things (IoT) based monitoring system for temperature and dissolved oxygen levels in catfish aquaculture pond water based on NodeMCU ESP8266. Monitoring system is using SEN0237 gravity analog dissolved oxygen sensor, DS18B20 sensor module, NodeMCU ESP8266, 20×4-character liquid-crystal display (LCD), micro secure digital (SD) card module, internet modem. Data from measurements of temperature and dissolved oxygen levels are stored online in the Adafruit.io database in the .csv format and on a micro secure digital (SD) card in the device in the .txt format. The lowest value of dissolved oxygen levels and temperature are 3.4 mg/L or 3.4 ppm and a temperature of 27.9 °C, respectively. Meanwhile, the highest value of dissolved oxygen levels and temperature are 4.6 mg/L or 4.6 ppm and temperature of 30.9 °C, respectively.&lt;/span&gt;

Raspberry Pi based IOT Weather Station

This paper presents a real-time system for monitoring and updating weather conditions online. The system tracks three key parameters: temperature, humidity, and rainfall. These values are displayed on an LCD screen and stored in a database. When the area is dry, the rainfall reading shows zero. If raindrops are detected, the rainfall value updates accordingly. As the temperature changes, it also reflects on the display. Users can check the weather status of a specific area from anywhere. We use an ARM-based Raspberry Pi 3 board, running the Raspbian operating system with a Linux kernel. The programming is done in Python, which is supported by the IDLE environment. This system provides users with a clear understanding of local weather conditions, making it a valuable tool for monitoring the climate in a specific area.

AC thin-film electroluminescence: A historical overview with a look ahead

50 years ago, television screens used bulky cathode ray tubes (CRTs) with a size limited to about 70 cm in diagonal (28 in.), while flat panel displays belonged to the realm of science fiction. Although the performance of CRTs in terms of energy consumption, size, and color rendering slowly improved, there were numerous applications where flat panel displays would present a tremendous advantage, notably for confined spaces and in portable equipment. Starting from the 1970s, AC thin-film electroluminescence (ACTFEL) was investigated as a high performance alternative to the—also emerging—liquid crystal displays (LCDs) and plasma display panels (PDPs). For a number of years, ACTFEL developed from the phase of fundamental research to commercial products (for monochrome displays) and full color prototype displays. However, due to the fast development and strong cost reduction of LCDs, ACTFEL did not remain competitive and most of the research activities were ceased. The current overview sketches a brief history of the ACTFEL technology, its merits and limitations, and the reasons why such displays still have their use in some niche applications.