Color Liquid Crystal Display Research Articles

Automatic Testing Technology of BTB Liquid Crystal Display Advanced Fault Detection in Smart Meter for Smart Machine

In smart meter technology, the reliability of Backplane to Bezel (BTB) Liquid Crystal Displays (LCDs) is crucial for efficient functioning within intelligent grid systems. Defects in these LCD screens can significantly impact overall smart meter performance, necessitating effective detection methods for proper management and utilization. Current detection approaches, which combine manual and automatic methods based on machine vision, have shown unsatisfactory performance. This research addresses this challenge by proposing a novel method for advanced fault detection in BTB LCDs of smart meters, Automatic Testing Technology of BTB Liquid Crystal Display Advanced Fault Detection in Smart Meter for smart machine (BTB-LCD-FD- MCDSGAN) is proposed. The study begins by collecting datasets specifically tailored for LCD screen localization and defect detection. To enhance data quality, a Window Adaptive Extended Kalman Filter (WAEKF) is applied during preprocessing for noise removal. Feature extraction follows, utilizing Parameterized Multi Synchrosqueezing Transforms (PMST) with a primary focus on Gray Level Co-occurrence Matrix features. These extracted features serve as input for classification by a Multimodal Contrastive Domain Sharing Generative Adversarial Network (MCDSGAN), categorizing defects into five types likes normal display, no display, abnormal display, liquid crystal rupture, and incomplete display. Furthermore, the proposed method optimizes the MCDSGAN weight parameter using the Red Fox Optimization Algorithm (RFOA) to achieve accurate LCD fault defect prediction. The entire approach is implemented in Python, performance metrics likes accuracy, precision, recall, F-score, computational time are thoroughly analyzed. Performance of proposed BTB-LCD-FD-MCDSGAN approach attains 20.89%, 33.67% and 25.98% high accuracy, and 17.98%, 23.78% and 33.45% higher recall compared with existing methods such as automatic detection of display defects for smart meters depend on deep learning (AD-AM-DL), deep learning-enabled image content-adaptive field sequential color LCDs by mini-LED backlight (DL-AFSC-LCD) and new multi category defect detection method depend on convolutional neural network technique for TFT-LCD panels (MDF-CNN-LCD), methods respectively.

Red phenanthrenequinone dyes with high thermal and photo-stability for LCD color filters

Color filters (CF) are essential integral parts of the liquid crystal display (LCD) and image sensor. Compared to traditional pigment colorants, organic dyes offer a promising alternative to realize CF with improved optical properties and higher resolution. However, organic dyes usually suffer from inferior thermal and photo-stability, limiting their applications in CF. Herein, four robust donor-acceptor organic dyes based on phenanthrenequinone chromophore were designed and synthesized by introducing aromatic amine derivatives as the electron donors. The strong donor-acceptor interactions in these dyes contribute to intense broad charge-transfer absorption bands from 375 nm to 600 nm with high molar extinction coefficients, thus realizing red color. Also, these dyes exhibit high thermal and photo-stability, good compatibility with the polymer binder and low aggregation tendencies, resulting in high thermal and photo-stability for the fabricated CF films. Remarkably, among these phenanthrenequinone dyes, DTPAP with multi-donor substitution and extended π-conjugation exhibited the best performance in terms of molar extinction coefficient, thermal and photo-stability, contributing to the highest thermal and photo-stability for the CF film with color difference values (ΔEab) below 0.75 under simulated industrial manufacturing processes. This work confirms that phenanthrenequinone is a robust chromophore and is conducive to developing thermal and photo-stable CF dyes, and paves a way to improve the optical properties and stability of donor-acceptor dyes for CF.

Reducing the Power Consumption of VR Displays with a Field Sequential Color LCD

To achieve 60 pixels per degree (PPD) and 100° field of view (FoV) while keeping a reasonably high aperture ratio for active-matrix liquid crystal displays (LCDs), field sequential color (FSC) is a promising approach. We evaluate the physical properties of a high birefringence nematic LC mixture and then use these data to simulate the performance of a fringe-field switching (FFS) LCD. Such an FFS LCD exhibits a fast average gray-to-gray response time (~1.5 ms) to enable FSC operation. By removing the spatial color filters, FSC operation triples the resolution density and optical efficiency, which are critical to high-resolution density and low power consumption virtual reality applications. Wide color gamut (96.2% of the DCI-P3 standard) and superior color uniformity are also demonstrated using such an FSC LCD.

Influence of monitor display resolution and displayed image size on the spatial resolution of ultra-high-resolution CT images: a phantom study.

To determine the optimal display conditions for ultra-high-resolution computed tomography (UHRCT) images in clinical practice, this study investigated the effects of liquid-crystal display (LCD) resolution and displayed image size on the spatial resolution of phantom images acquired using a UHRCT system. A phantom designed to evaluate the high-contrast resolution was scanned. The scan data were reconstructed into four types of UHRCT image series consisting of the following possible combinations: two types of reconstruction kernels on the filtered back-projection method (for the lung and mediastinum) and two types of matrix sizes (10242 and 20482). These images were displayed under eight types of display conditions: three image sizes displayed on a 2-megapixel (MP) and 3-MP color LCD and two image sizes on an 8-MP color LCD. A total of 32 samples (four image series × eight display conditions) were evaluated by eight observers for high-contrast resolution. The high-contrast resolution of the displayed UHRCT images was significantly affected by the displayed image size, although the largest (full-screen) displayed image size did not necessarily show the maximum high-contrast resolution. When the images were displayed in the full-screen size, LCD resolution affected the high-contrast resolution of only the 20482-matrix-size images reconstructed using the lung kernel. In conclusion, the spatial resolution of UHRCT images may be affected by LCD resolution and displayed image size. To optimize the clinical display conditions for UHRCT images, it is necessary to adopt an LCD with an adequate resolution for each viewing situation.

P‐16.14: Research of Optical Influence on LCD by OGM Products

This paper aims to explore the influence mechanism and range of OGM (One Glass Solution, Metal Mesh) on LCD (Liquid Crystal Display) optical performance. Firstly, the basic concepts and calculation methods of color coordinates and other parameters are introduced; Then the laminated structure of TLCM is introduced, and the transmission spectrum of each layer is tested in different experiments, which points out that the most important influencing factor is the OC insulating layer due to the low light transmittance at low wavelength; Finally, the influence range of OGM on LCD's brightness, color coordinate, color temperature, color gamut and blue light proportion are pointed out, among them, the brightness and color temperature decrease by respectively about 6.0% and 6.25%. The above work analyzes the luminance and chromaticity changes of LCD products after OGM lamination, which provides theoretical and data reference for the design of new products in the future.

38‐2: Invited Paper: 12.3‐in Highly Transparent LCD by Scattering Mode with Direct Edge Light and Field‐Sequential Color‐Driving Method

We have newly developed 12.3‐inch highly transparent color liquid crystal display (LCD) which has no color filter, no polarizer and no back light. For the improvement of optical performance and lager sized panel, the process of scattering liquid crystal, panel structure and driving scheme were optimized. We have successfully achieved high transmittance as 87% and high contrast ratio as 32:1 which is 2 times larger than previous 4‐inch model.

Assessment Tool of Image Quality for Medical Liquid-crystal Displays Using Commercially Available Digital Cameras

We developed a simplified tool for measuring image quality of medical liquid-crystal displays (LCDs) using a commercially available color digital camera. This tool implemented as a plug-in software for ImageJ (open-source image processing program) was designed to compute modulation transfer functions (MTFs) and Wiener spectra (WS) of monochrome and color LCDs from LCD photographed images captured by a camera. The intensities of the red (R), green (G), and blue (B) signals of the unprocessed image data depend on the spectral sensitivity of the image sensor used in the camera. In order to evaluate image quality based on LCD luminance, the plug-in software calibrates the RGB signals from the camera using measured luminance of the LCD and converts them into grayscale signals that correspond to the luminance of the LCD. The MTFs and WS are determined based on the line response from a one-pixel line image and the one-dimensional noise profiles acquired by scanning the uniform image using numerically synthesized slit, respectively. With this plug-in software for ImageJ, we are able to readily compute MTFs and WS of both monochrome and color LCDs from unprocessed image data of cameras. Our simplified tool is helpful to evaluate and understand the physical performance of LCDs for a large number of display users in hospitals and medical centers.

Super Ultra-High Resolution Liquid-Crystal-Display Using Perovskite Quantum-Dot Functional Color-Filters

Quantum dot enhancement film (QDEF) working in tandem with a blue light-emitting-diode (LED) back-light-unit (BLU) has been recently used in liquid crystal display (LCD) to minimize the cross talks between the polarized emitting B-, G-, and R-light. However, they still exhibit a fundamental and considerable emitting-light-power loss from QDEF because of the light absorption loss in resin and transparent films of QDEF. In this work, we propose and demonstrate the superiority of the LCD using blue-(B-), green-(G-), and red-(R-) perovskite-quantum-dot (PrQD) functional CFs coupled with a blue LED BLU. This LCD using PrQD functional CFs and a blue LED BLU features cross-talk free spectra of polarized emitting B-, G-, and R-light, maximizing the LCD color gamut and exhibiting a world record performance of over 102.7% (137%) of Rec.2020 standard (NTSC standard). Theoretically, such an improvement in color gamut would facilitate unlimited scaling-down of the pixel leading to super ultra-high resolution LCD.

P‐139: The Investigation of Field Sequence Color Liquid Crystal Display with New Polymer Stabilized Vertical Alignment Mode

In this paper, a field‐sequential‐color liquid crystal display (FSC LCD) based on new polymer stabilized vertical alignment (N‐PSVA) liquid crystal display mode and photo alignment technology have been developed. An excellent response time of the device can be obtained by the developed of N‐PSVA LC and the optimizing of process, with the operating voltage keep in 10V. By this work, the 32 inch large size FSC TV panels were presented

A flexible optically re-writable color liquid crystal display

It is very difficult to make a liquid crystal display (LCD) that is flexible. However, for an optically re-writable LCD (ORWLCD), only the spacers and the substrates need to be flexible because the driving unit and the display unit are separate and there are no electronics in the display part of ORWLCD. In this paper, three flexible-spacer methods are proposed to achieve this goal. A cholesteric liquid crystal colored mirror with a polarizer behind it is used as the colored reflective backboard of an ORWLCD. Polyethersulfone substrates and flexible spacers are used to make the optically re-writable cell insensitive to mechanical force.

Effect of Color Temperature on Color Scale Test Patterns in Medical Liquid-crystal Display Monitor

In Japan, medical liquid-crystal display (LCD) and general LCD monitors have color temperatures of 7500 and 6500 K, respectively. The differences in color temperature make it difficult for radiologists to judge whether the same color is being displayed on the monitor. Therefore, the radiologist may overlook lesions. We examined chromaticity on a color scale test pattern to determine the relationships between color temperature (6500-12,500 K) of the medical color LCD monitors, there are three types of fluorescent light and three types of illuminance LCD monitors. As the color temperature of the monitor increased, the variation in chromaticity for grayscale test patterns increased and those variations for the blue scale test patterns decreased in a dark room and at 600 lux. In addition, even if the color temperature of the monitor was changed, the variation in chromaticity showed no change under fluorescent lighting with light bulb color and daylight color. The results of this study will be useful for quality control and quality assurance of medical LCD monitors in terms of illuminance and color temperature of the monitor.

Effective luminance deterioration of medical liquid crystal displays in clinical use.

The objective of this work was to evaluate the maximum luminance (L max) level of medical liquid crystal displays (LCDs) as a function of backlight hours (BLH) annually. The L max values for 249 2-megapixel color LCDs (RadiForce RX210, EIZO Corporation) were measured in February 2014, 2015, and 2016. Four near-range luminance meters and the built-in type luminance meters, each with an LCD, were used for the measurements. The average and standard deviation (SD) of BLH measured in 2014 was 15,371±8219h. Four, twenty, and thirty-nine LCDs failed in the constancy tests performed in February 2014, 2015, and 2016, respectively, i.e., they were unable to output 170cd/m2. The SD of L max increased each year and as BLH became longer. In conclusion, evaluation of L max as a function of BLH during constancy testing will help predict the decrease in L max of a clinically used medical color LCD.

79‐4L: Late‐News Paper: Highly Transparent LCD using New Scattering‐type Liquid Crystal with Field Sequential Color Edge Light

We have developed highly transparent color liquid crystal display (LCD) using newly developed scattering‐type liquid crystal, which shows transparent state when voltage is not applied, with field sequential color (FSC) driving method without employing color filter and polarizer. Furthermore the light is directly introduced to the panel glass substrates from the edge of the substrates (not from back surface). At surface of the substrates, the light takes a total reflection by difference of refractive index between glasses and air. So the light propagates through the substrate. On the other hand, when a voltage as higher than a threshold voltage (Vth) is applied to liquid crystal (LC) layer, the light is scattered towards the viewers. This newly developed display has high transmittance (80%), wide color gamut and fast response time.

Evaluation of a new test pattern for daily quality assurance of medical display monitors

Introduction In the visual evaluation of daily quality assurance (QA) of medical display monitors, some well-established test patterns are available; however, the same pattern is always used. Therefore, it is difficult to detect luminance deterioration. Purpose We developed the new software for the daily QA of monitors (mdQA), in which randomized object (RO) patterns were generated. The RO patterns had a low-contrast object consisting of a randomly located sphere. In the present study, we evaluated whether these RO patterns can detect luminance deterioration. Materials and methods The mdQA was developed using Microsoft Visual Basic 2010 Express. The digital driving level (DDL) and the standard deviation (SD) of the RO pattern background, as well as the size and contrast of the object, were adjustable. In this study, the DDL and SD were set at 130 and 20, respectively. The object diameter was determined at 30 pixels. Contrast values varied from 4 to 8 pixels. We produced 40 patterns with and without the object using the mdQA. A receiver operating characteristic analysis was performed for the two different display luminance (400 and 320 cd/m 2 ) using a 2-megapixel color liquid crystal display (LCD) monitor. Ten radiation therapists observed the patterns and scored the confidence rate using a continuous scale. Results There was a statistically significant difference between the two LCD monitor conditions ( p Conclusion The developed mdQA enables the creation of RO patterns for the daily QA of medical display monitors; these RO patterns are useful in detecting luminance deterioration. Disclosure None.

A method for evaluating image quality of monochrome and color displays based on luminance by use of a commercially available color digital camera.

The aim of this study is to propose a method for the quantitative evaluation of image quality of both monochrome and color liquid-crystal displays (LCDs) using a commercially available color digital camera. The intensities of the unprocessed red (R), green (G), and blue (B) signals of a camera vary depending on the spectral sensitivity of the image sensor used in the camera. For consistent evaluation of image quality for both monochrome and color LCDs, the unprocessed RGB signals of the camera were converted into gray scale signals that corresponded to the luminance of the LCD. Gray scale signals for the monochrome LCD were evaluated by using only the green channel signals of the camera. For the color LCD, the RGB signals of the camera were converted into gray scale signals by employing weighting factors (WFs) for each RGB channel. A line image displayed on the color LCD was simulated on the monochrome LCD by using a software application for subpixel driving in order to verify the WF-based conversion method. Furthermore, the results obtained by different types of commercially available color cameras and a photometric camera were compared to examine the consistency of the authors' method. Finally, image quality for both the monochrome and color LCDs was assessed by measuring modulation transfer functions (MTFs) and Wiener spectra (WS). The authors' results demonstrated that the proposed method for calibrating the spectral sensitivity of the camera resulted in a consistent and reliable evaluation of the luminance of monochrome and color LCDs. The MTFs and WS showed different characteristics for the two LCD types owing to difference in the subpixel structure. The MTF in the vertical direction of the color LCD was superior to that of the monochrome LCD, although the WS in the vertical direction of the color LCD was inferior to that of the monochrome LCD as a result of luminance fluctuations in RGB subpixels. The authors' method based on the use of a commercially available color camera is useful to evaluate and understand the display performances of both monochrome and color LCDs in radiology departments.

WE-D-204-02: Novel Method for Correcting Degradation of Sharpness of Liquid-Crystal Display Based On Modulation Transfer Function

Purpose: To develop a method for improving sharpness of images reproduced on liquid-crystal displays (LCDs) by compensating for the degradation of modulation transfer function (MTF) of the LCD. Methods: The inherent MTF of a color LCD (display MTF) was measured using a commercially available color digital camera. The frequency responses necessary to compensate for the resolution property of the LCD were calculated from the inverses of the display MTFs in both the horizontal and vertical directions. In addition, the inverses of the display MTFs were combined with the response of the human eye. The finite impulse response (FIR) filters were computed by taking the inverse Fourier transform of the frequency responses, and the effects of the FIR filtering on both the resolution and noise properties of the displayed images were verified by measuring the MTF and Wiener spectrum (WS), respectively. The FIR filtering was then applied to the representation of digital bone and chest radiographs. Results: The FIR filtering improved the MTF values by up to almost 1.0 or greater over the frequency range of interest, while it minimally increased the WS values. Combining the inverses of the display MTFs with the response of the human eye led to further refinement of the MTF. Our method was successfully and beneficially applied to the image interpretation of bone radiographs. The resolution enhancement of chest radiographs, which include larger scattered radiation than bone radiographs, was easily perceived by incorporating the response of the human eye. In addition, no artifacts were observed on the processed images. Conclusion: Our proposed method to compensate for the degradation of the resolution properties of LCDs has the potential to improve the observer performance of radiologists when reading digital radiographs. This work was supported in part by grant from EIZO Corporation.

Synthesis and characterization of novel perylene dyes with new substituents at terminal-position as colorants for LCD color filter

Six novel red perylene dyes were synthesized by modifying the bay- and terminal-positions of perylene main body to improve the optical performances of liquid crystal display (LCD) color filters. The absorption properties, solubility in industrial solvents and thermal stabilities of the dyes were examined to evaluate the dyes for dye-based LCD color filter. Mill bases and spin-coated color filters were formulated and fabricated using the synthesized dyes. Transmittance, dye aggregation and thermal stabilities of the prepared color filters were investigated using a color spectrophotometer. Geometric structures of the synthesized dyes were optimized by using Gaussian program. Five of the synthesized dyes showed acceptable optical properties as colorants for LCD color filters. Also, the synthesized dyes and prepared color filters exhibited suitable thermal stability for the application. Furthermore, the prepared color filters exhibited superior transmittances than pigment-based color filters at 650 nm. Their physical properties were closely related with chemical structures investigated by geometry optimization.

Synthesis and characteristics of metal-phthalocyanines tetra-substituted at non-peripheral (α) or peripheral (β) positions, and their applications in LCD color filters

Four metal-phthalocyanine dyes were synthesized to evaluate the variation of their properties with both the position of the substituents and the type of metal used for coordination. The substituent, ethyl 4-hydroxy-3-methoxybenzoate, was introduced at the non-peripheral (α) or the peripheral (β) position in order to improve the solubility of the phthalocyanine. Cu and Zn were chosen as coordination metals, both to increase thermal stability and to fine-tune the color of the complex. The resulting complexes were highly soluble in a range of organic solvents as well as industrial solvents, such as di(propylene glycol) methyl ether acetate, diethylene glycol monobutyl ether acetate, and propylene glycol methyl ether acetate. The solubility of the dyes substituted at the α-position was higher than that of β-substituted dyes. Structural analyses of the substituted phthalonitriles were achieved using 1H and 13C NMR spectroscopy, and high-resolution mass spectrometry. The structures of the dyes were confirmed by MALDI-TOF spectroscopy and FT-IR spectrophotometry. The optical properties and thermal stabilities of the dyes were estimated by UV–Vis spectrophotometry and thermogravimetric analysis. The synthesized dyes were cyan in color, and thus could be successfully applied in six-primary-color (RGBCMY) liquid crystal display (LCD) color filters in order to improve the color gamut. Dye-based color filters showing adequate optical spectra for LCD cyan color filters were manufactured. Appropriate compensating dyes were also required in order to cut off undesirable transmittance peaks.

Imaging Evaluation for Simulated RGBW Color LCDs With the Proposed Color Conversion Algorithm

This paper is a comparative evaluation of imaging performance for two types of color liquid crystal displays (LCDs) with Quad RGBW (red, green, blue, and white) and Stripe RGB (red, green, blue) pixel units by means of simulation study. In accordance with the study results, using the proposed color conversion algorithm could achieve color consistence and higher luminance for rendering images with RGBW rather than RGB pixel units. Simultaneously, instrumental color measurement via a spectrometer was done which results also proved that almost same color values of rendering images with RGBW pixel units as well as those images with original RGB pixel units, and higher luminance was achieved. Finally, the pseudocolor phenomenon of rendering images with RGBW pixel units is analyzed and discussed on the basis of human vision model.

Questionnaire survey on the use of a novel artificial pancreas by intensive care unit nurses.

The introduction of a color liquid-crystal display (LCD) on a novel artificial pancreas (STG-55, Nikkiso Co. Ltd. Tokyo, Japan) allowed nurses to more easily monitor changes in patients' blood glucose levels, compared to the previous model (STG-22). This study was conducted to examine the hypothesis that the STG-55 provided nurses with a feeling of security due to the introduction of the LCD screen. A questionnaire survey was conducted 6 months after the STG-55 was introduced (Survey 2012), among intensive care unit (ICU) nurses who had used both the STG-22 and the STG-55 for patient glycemic control. The results were then compared with the results from a questionnaire survey that was conducted after the STG-22 was introduced (Survey 2006). All ICU nurses (n = 19) responded to Survey 2012, and 95% of these nurses had responded to Survey 2006 (n = 19). After the introduction of the STG-22, 11 nurses (58%) reported becoming conscious of anxiety regarding hypoglycemia when they performed conventional glucose control with the sliding scale method. This anxiety awareness increased significantly (19 nurses, 100%; p < 0.01) after the STG-55 was introduced. However, there were no significant differences in the proportion of respondents who requested improvements in the blood withdrawal process. In conclusion, the results of our survey indicate that all ICU nurses became conscious of anxiety regarding the risk of hypoglycemia when using the conventional sliding scale method after the introduction of the STG-55. However, the respondents were not satisfied with the STG-55, due to difficulties encountered during blood withdrawal.