High Resolution Liquid Crystal Display Research Articles

High-resolution low-cost LCD 3D printing for microfluidics and organ-on-a-chip devices.

The fabrication of microfluidic devices has progressed from cleanroom manufacturing to replica molding in polymers, and more recently to direct manufacturing by subtractive (e.g., laser machining) and additive (e.g., 3D printing) techniques, notably digital light processing (DLP) photopolymerization. However, many methods require technical expertise and DLP 3D printers remain expensive at a cost ∼15-30 K USD with ∼8 M pixels that are 25-40 μm in size. Here, we introduce (i) the use of low-cost (∼150-600 USD) liquid crystal display (LCD) photopolymerization 3D printing with ∼8-58 M pixels that are 18-35 μm in size for direct microfluidic device fabrication, and (ii) a poly(ethylene glycol) diacrylate-based ink developed for LCD 3D printing (PLInk). We optimized PLInk for high resolution, fast 3D printing and biocompatibility while considering the illumination inhomogeneity and low power density of LCD 3D printers. We made lateral features as small as 75 μm, 22 μm-thick embedded membranes, and circular channels with a 110 μm radius. We 3D printed microfluidic devices previously manufactured by other methods, including an embedded 3D micromixer, a membrane microvalve, and an autonomous capillaric circuit (CC) deployed for interferon-γ detection with excellent performance (limit of detection: 12 pg mL-1, CV: 6.8%). We made PLInk-based organ-on-a-chip devices in 384-well plate format and produced 3420 individual devices within an 8 h print run. We used the devices to co-culture two spheroids separated by a vascular barrier over 5 days and observed endothelial sprouting, cellular reorganization, and migration. LCD 3D printing together with tailored inks pave the way for democratizing access to high-resolution manufacturing of ready-to-use microfluidic and organ-on-a-chip devices by anyone, anywhere.

All-Inorganic Green Synthesis of Small-Sized and Efficient K2SiF6:Mn4+ Phosphor for Mini-LED Displays.

High-resolution liquid crystal display (LCD) backlight requires a color conversion layer featuring micrometer light-emitting particles and a uniform morphology. The widely used commercial red-emitting K2SiF6:Mn4+ phosphor, showing promise as a light-conversion candidate, faces limitations due to its toxic synthesis process, large particle size, and poor moisture resistance. We successfully demonstrated an efficient substitution of the highly toxic HF/TEOS/KHF2 solvent system with a commonly used HCl/SiO2/KF solvent system to synthesize the small-sized K2SiF6:Mn4+ phosphor. Additionally, surface passivation was performed to enhance the luminescence intensity and resistance to moisture, denoted as K2SiF6:Mn4+@CaF2. Accordingly, the K2SiF6:Mn4+@CaF2 phosphor presents a high luminescence efficiency (99.87%/32.84% IQE/EQE) with an average particle size of ∼2.67 μm. Notably, after exposure to 85% humidity and 85 °C temperature for 3 h, the luminescence intensity remains at 47.4% for K2SiF6:Mn4+@CaF2, while 21.2% for pristine K2SiF6:Mn4+, and only 3.5% for K2SiF6:Mn4+ synthesized by TEOS. These advancements hold great potential for improving high-resolution LCD backlighting, particularly for displays with micron-level pixels, opening up new possibilities for enhanced display technology.

FPC Design Guidelines for Enabling High-Speed Intrapanel Interface in Large-Size LCD TVs

In this work, we propose flexible printed circuit (FPC) design guidelines for high-speed signal implementation in large-size and high-resolution liquid crystal display (LCD) TV modules by analyzing signal integrity (SI) characteristics through simulation and measurement. We observed that designing an FPC for LCD TV modules that can minimize insertion loss and crosstalk in the channel is critical to successfully implementing multi-Gbps signal characteristics in large-size and high-resolution LCD TV modules. To prove this experimentally, we investigated the trends of insertion loss, impedance, and crosstalk, which are design parameters of simulation-based FPCs, and designed four FPC samples assuming their application to the intra-panel interface module of a real 75-inch LCD TV. Then, based on the measured S-parameter model, the SI performance was verified and compared by measurement and simulation to demonstrate the validity of the proposed design guidelines. In conclusion, to achieve the SI characteristics of FPCs in LCD TV modules, it is necessary to consider minimizing insertion loss and mitigating crosstalk more than any other electrical performance by enabling the differential P/N pairs to have a strong coupling relationship.

60‐4: Distinguished Paper: Novel Pancake‐Based HMD Optics to Improve Light Efficiency

Recently, compactness of Head Mounted Display (HMD) product has been strongly required to improve comfortableness of user. The folded optics, so‐called ‘Pancake optics', is suitable for realizing compact HMD, but there is a big drawback of lowering light efficiency. To overcome this problem, we propose novel pancakebased HMD optics named ‘Double path pancake optics' using two light paths. The optical simulation is performed and we fixed the appropriate design. From our simple evaluation of transmittance, we conclude that light efficiency of ‘Double path pancake optics' becomes 1.8 times higher than conventional pancake optics. We made the prototype using 1,200ppi high resolution Liquid Crystal Display (LCD) and confirmed that the high image quality can be displayed.

Novel pancake‐based HMD optics to improve light efficiency

AbstractRecently, compactness of head‐mounted display (HMD) products have been strongly required to improve comfortableness of user. The folded optics, so‐called “Pancake optics”, is suitable for realizing compact HMD, but there is a big drawback of lowering light efficiency. To overcome this problem, we propose a novel pancake‐based HMD optics named “Double path pancake optics” using two light paths. The optical simulation is performed to find highly optimized optical properties such as thickness, and field of view (FOV). As a result of the simulation, we fixed the appropriate design. From our simple evaluation of both brightness and transmittance, we conclude that light efficiency of “Double path pancake optics” becomes 1.8 times higher than conventional pancake optics. We made the prototype using 1200 ppi high resolution liquid crystal display (LCD) and confirmed that the high image quality can be displayed.

Antenna-on-Display Concept on an Extremely Thin Substrate for Sub-6 GHz Wireless Applications

This communication presents a concept of a sub-6 GHz antenna-on-display (AoD) that can eventually be integrated into the transparent area of a display panel of various wireless devices for the first time in the literature. The transparency of the proposed microwave AoD is realized using metal mesh conductive film and features optical transparency, which is compatible with high-resolution liquid crystal display (LCD)/organic light-emitting diode (OLED) display panel requirements. To maximize the radiation efficiency despite the extremely thin substrate ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.0048\lambda _{0}$ </tex-math></inline-formula> ), a traveling-wave antenna topology is inspired and further modified to incorporate the inherent structural limitations of modern-day high-resolution display panels. Eventually designed to operate in a leaky-wave mode, a novella dedicated feeding mechanism is introduced to minimize undesired coupling between the antenna structure and the display panel. The composite right-/left-handed (CRLH) unit cell employs a single shunt inductor topology to maximize the radiation efficiency. The measured 6 dB impedance bandwidth of the proposed microwave AoD is from 2.36 to 6.17 GHz, which is consistent with the fast wave region of the proposed unit cell. The measured realized gain of the microwave AoD consisting of 13 unit cells is 2.68 dBi at 5.5 GHz with a radiation efficiency of 62.5%. This is the first demonstration to ascertain that an AoD topology can be applicable at microwave applications while reducing the antenna-to-ground distance by approximately a factor of 20 compared to previous studies.

Tilted LCD Pixel With Liquid Crystal GRIN Lens for Two-Dimensional/Three-Dimensional Switchable Display

In this paper, high images quality switchable two-dimensional (2-D)/3-D display is achieved by carefully matching the high-resolution liquid crystal display (LCD) pixel structure and liquid crystal graded index (GRIN) lens. A parallelogram LCD pixel structure is proposed, in which the edges of each sub-pixels are slanted. At the top of the LCD pixels, the liquid crystal GRIN lens is also tilted to reduce the moire effect and the tilt angle is carefully aligned with the edges of subpixels of LCD. This accurate alignment is useful to eliminate the crosstalk and improves the imaging quality of 3-D display. The 2-D/3-D switchable display is realized by tuning the liquid crystal in the GRIN lens. Based on this, a 3-D display based on 32-inch 8K4K resolution LCD display and Liquid crystal GRIN lens was designed.

Rapid and Inexpensive Fabrication of Multi-Depth Microfluidic Device using High-Resolution LCD Stereolithographic 3D Printing

With the dramatic increment of complexity, more microfluidic devices require 3D structures, such as multi-depth and -layer channels. The traditional multi-step photolithography is time-consuming and labor-intensive and also requires precise alignment during the fabrication of microfluidic devices. Here, we present an inexpensive, single-step, and rapid fabrication method for multi-depth microfluidic devices using a high-resolution liquid crystal display (LCD) stereolithographic (SLA) three-dimensional (3D) printing system. With the pixel size down to 47.25 μm, the feature resolutions in the horizontal and vertical directions are 150 μm and 50 μm, respectively. The multi-depth molds were successfully printed at the same time and the multi-depth features were transferred properly to the polydimethylsiloxane (PDMS) having multi-depth channels via soft lithography. A flow-focusing droplet generator with a multi-depth channel was fabricated using the presented 3D printing method. Experimental results show that the multi-depth channel could manipulate the morphology and size of droplets, which is desired for many engineering applications. Taken together, LCD SLA 3D printing is an excellent alternative method to the multi-step photolithography for the fabrication of multi-depth microfluidic devices. Taking the advantages of its controllability, cost-effectiveness, and acceptable resolution, LCD SLA 3D printing can have a great potential to fabricate 3D microfluidic devices.

Robust Gate Driver on Array Based on Amorphous IGZO Thin-Film Transistor for Large Size High-Resolution Liquid Crystal Displays

Amorphous IGZO thin-film transistors (TFTs) in an etch stop layer (ESL) structure was processed on 2500 mm $\times $ 2200 mm size substrate. The fabricated devices exhibit enhancement mode characteristics, and excellent uniformity over large area. The presented good operational stabilities under both positive gate bias temperature stress (PBTS) and negative gate bias temperature stress (NBTS) tests can well meet the requirements for pixel switching. However, considering even threshold voltage shift under long term positive bias stress might affect proper operation of the gate driver on array (GOA), a design with a pulse gating scheme is proposed, consisting of 13 TFTs and 1 capacitor, to avoid long term continuous bias stressing of the TFT. With the proposed GOA design, a 32-inch QUHD ( $7680\times 4320$ ) high-resolution liquid crystal display (LCD) panel with a 7 mm wide bezel is achieved. The reliability of the GOA circuit is well proved through standard aging tests.

Novel quantum dot enhancement film with a super-wide color gamut for LCD displays

We present a novel quantum dot enhancement film (QDEF) with a remarkable RGB color gamut of over 100.4% (134.2%) of the Rec. 2020 standard (NTSC standard), respectively for a high-resolution liquid-crystal display (LCD). Our efficient QDEF was fabricated by using a highly transparent resin incorporated with high photoluminesce-quantum yield (PL-QY) and narrow full width at half maximum CsPbBr1I2 QDs (Pr-QDs) and CdSe/ZnS QDs (Cd-QDs). The proposed PrCd-QDEF in a LCD with color filters rendered a blue photoluminesce (PL) peak at 452 nm with a FWHM of 20.4 nm, a green PL peak at 530.1 nm with a FWHM of 23.8 nm, and a red color peak at 652.4 nm with a FWHM of 28.1 nm. Moreover, The PrCd-QDEF did not show any cross-talk between the RGB PL colors. Such promising optical results, along with the simple and cost-effective preparation technique, might encourage the manufacture of super high resolution LCDs using a PrCd-QDEF.

Improvement of TFT Characteristics for Low-Temperature Solution-Processed Oxide Semiconductors with Hydrogen Injection and Oxidation Process

Thin-film transistors (TFTs) using oxide semiconductors have attracted much attention for switching and driving devices in large-screen, high-resolution liquid crystal display (LCD) and organic light-emitting diode (OLED) displays because of their high mobility1-3. As an advanced oxide TFT fabrication method, the solution-process is widely researched due to advantages such as its low process cost, large-scale fabrication capacity, and the simplicity of the process. However, several drawbacks of the solution-process must be addressed for display applications. One of the key points is the trade-off between the processing temperature and the TFT characteristics. From previous research on solution-processed oxide TFTs, it has been reported that low-temperature-processed TFTs are generally inactive below 400 °C due to a lack of metal-oxide-metal bond formation and decomposition of the residual species4,5. However, a low-temperature process is strongly required for application to plastic substrates for flexible displays and flexible electronics devices.In addition, a low-temperature process is important to achieve low fabrication costs. Here, we demonstrate improvement of the TFT characteristics by application of a hydrogen injection and oxidation (HIO) process for low-temperature solution-processed oxide TFTs. From a technical standpoint, we consider that the important factor is how to efficiently decompose the residual species. The solution-processed oxide TFTs exhibit inferior device performance when a few residual species remain. Therefore, a reduction reaction is initiated by a hydrogen injection process to decompose the residual spices. The characteristics of a TFT based on indium gallium zinc oxide (IGZO) were evaluated, such as the field effect mobility and the threshold voltage (Vth) shift under positive and negative bias stress. The maximum temperature for the entire fabrication process was as low as 300 °C. Solution-processed IGZO thin films were fabricated by a spin-coating method onto 200 nm thick thermally oxidized SiO2/n+-Si substrates and annealing at 300 °C for 1 h. The IGZO precursor was prepared from 0.3 M solutions of indium nitrate hydrate (In(NO3)3·xH2O), gallium nitrate hydrate (Ga(NO3)3·xH2O), and zinc nitrate hydrate (Zn(NO3)2·xH2O) in pure water. The composition ratio for In:Ga:Zn was set to 4:1:1. Hydrogen plasma treatment was adopted for the hydrogen injection process with subsequent annealing at 300 °C for 1 h. After fabrication of the IGZO film, the active area of the IGZO film was defined using a conventional photolithography method. Patterned source/drain (S/D) electrodes (Mo) were formed on the IGZO thin films using a shadow mask. Figure 1 shows the transfer characteristics of the IGZO TFT with and without the HIO process. The transfer characteristics of these IGZO TFTs for gate voltages (Vg) ranging from -30 to 30 V were measured at a fixed drain voltage (Vd) of 30 V. After the HIO process for the IGZO TFTs, the field effect mobility was significantly improved from 2.1 cm2/Vs to 4.8 cm2/Vs. Figure 2 shows the results for the threshold voltage shift (ΔVth) under a positive gate bias stress (PBS) of 20 V and a negative gate bias stress (NBS) of -20 V, with and without the HIO process. The stress time was set to 1 h at the maximum. Improvement of the reliability was confirmed: the Vth shift was less than 0.25 V for PBS and -2 V for NBS. The trap sites of any residual species or defect states in active channels were thus efficiently suppressed by the hydrogen injection process. In addition, the oxidation process may enhance the metal-oxide-metal bond formation. In conclusion, the HIO process as a combination of hydrogen reduction reaction and oxidation was demonstrated as effective for the improvement of solution-processed oxide TFTs. Improvement of the TFT characteristics was confirmed in terms of the field effect mobility and the Vthshift under PBS and NBS. Therefore, we consider that this new approach will lead to the development of high-performance solution-processed oxide TFTs in future. 1K. Nomura, H. Ohta, A. Takagi, T. Kamiya, M. Hirano, and H. Hosono, Nature 432, 488 (2004). 2K. Nomura, H. Ohta, K. Ueda, T. Kamiya, M. Hirano, and H. Hosono, Science 300, 1269 (2003). 3L. Wang, M. Yoon, G. Lu, Y. Yang, A. Facchetti, and T.J. Marks, Nature materials 5, 893 (2006). 4 M. G. Kim, M. G. Kanatzidis, A. Facchetti, and T. J. Marks, Nature materials 5, 382 (2011) 5 S. Jeong, Y. G. Ha, J. Moon, A. Faccchetti, T. J. Marks, Advanced materials 22, 1346 (2010) Figure 1

Charge Conservation Technique to Reduce Dynamic Power of Class AB Amplifier for LCD using LTSpice

complementary differential amplifier which has RAIL TO RAIL feature with offset cancellation technique to enhance high color depth and high-resolution liquid crystal display (LCD) drivers, is proposed. The dual complementary differential pairs are used to obtain RAIL TO RAIL input- output swing and an offset canceling capability. Both offset voltage and injection-induced error, due to mismatch of device and charge injection, are greatly reduced. The offset cancellation and charge conservation, which is used to reduce the dynamic power consumption, are operated during the same time slot so that the driving period does not need to increase. It is implemented using LTSPICE simulation.

67.2: A Novel Driving Method to Compensate for RC Delay of Ultra‐Large Size and High Resolution Liquid Crystal Displays

AbstractWe propose a novel method to drive ultra‐large size and high resolution LCD TV with a single‐bank data driver scheme without severe image degradation. We could achieve a maximum luminance and uniformity to be 98cd/m2 and 86%, respectively when gray 128 is displayed. This confirms excellent performance because the conventional dual‐bank driver scheme achieves the counterparts to be 90cd/m2 and 93%.

Human spatial processing accounts for dynamic range and color

Silver halide photography has a fixed response to scenes. Films count photons, and that results in a count-dependent optical density. The range of the film’s sensitivity to light, as well as its optical density, is determined in the factory where the film is made. However, digital imaging makes it possible to render wider ranges of light intensity, therebymore closely reproducing the variations in illumination that are found within scenes. With better imaging hardware, it is now possible to improve the range of light sensors and displays, and increase the number of digital quantization levels. It should also be possible to make more accurate reproductions over a greater range of light intensities. Raw formats in today’s commercial cameras enable more bits per pixel.1 A sensor’s dynamic range is the ratio of the amount of light that causes its maximum response to the light that causes its minimum response. Active pixel processing has led to techniques that can increase the sensor’s dynamic range to a ratio of 1010 to 1.2–4 For displays, Seetzen et al. used an ‘unsharp mask’ technique to illuminate a high-resolution liquid-crystal display with an out-of-focus, modulated array of LED illuminators,5 and make digital high-dynamic-range (HDR) displays with the ratio of maximum light emission tominimum emission of 105 to 1 and a 1500cd/m2 maximum screen luminance.6 As we start to incorporate these techniques in imaging, the question becomes, how much of the 1010 range of the sensor response and the 105 range of the displays can we actually use? In 1941, Jones and Condit measured the range of light in 128 outdoor scenes and the camera responses to them.7 They also measured the range on each camera’s film plane, and showed that the optical veiling glare (scattered light), not the sensor signal-to-noise, sets the usable dynamic range of cameras. They Figure 1. Two opposing spatial mechanisms control the appearance of gray patches.

ＲＯＣ解析による患者体動に起因する不鋭の検出能の評価 ―ファントム画像による診断用ＬＣＤと画像プレビュー用ＬＣＤの比較―

To evaluate the detectability of image unsharpness due to a patient's movement, a receiver operating characteristic (ROC) analysis was conducted to compare the diagnostic and preview liquid-crystal displays (LCDs). Phantom images that simulated a patient's movement were obtained by using a moving metronome and acrylic plates with a computed radiography (CR) system. A total of 104 images were classified into five groups according to the degrees of image unsharpness determined based on the metronome velocity and exposure time. In an ROC observer study (n=6), a 2-megapixel diagnostic monochrome LCD (2M-LCD) and a 1.3-megapixel general color LCD for preview (1.3M-LCD) were compared in terms of the detection of image unsharpness due to the movement. A statistical test was performed using the multi-reader multi-case (MRMC) method. In the results, the average areas under the ROC curve values for the detection of image unsharpness using the 2M-LCD and 1.3M-LCD were 0.952 and 0.850, respectively. The detection of image unsharpness using the 2M-LCD was significantly better than that using the 1.3M-LCD (p<0.05). In addition, some images with slight unsharpness were identified correctly only using the 2M-LCD. The results suggest that the low-resolution LCD (i.e., the 1.3M-LCD for preview) had a limitation in identifying image unsharpness due to the patient's movement. Slight unsharpness could be missed in primary image checks performed on a preview monitor equipped with an imaging system. Therefore, the high-resolution LCD (i.e., a 2M-LCD) is necessary when using radiography for diagnostics.

Patient setup verification procedure for a portal image in a computed radiography system with a high-resolution liquid-crystal display monitor

In our conventional visual inspection for setup verification, we have routinely used a console monitor of a CR system and a monitor of a treatment-planning system (i.e., the separate-monitor method) in order to avoid the need for CR portal-film generation. However, the separate-monitor method provided insufficient precision in detecting setup errors. We devised a setup verification procedure that uses a high-resolution liquid-crystal display monitor (i.e., the single-monitor method). Our objective in the present study was to evaluate the precision of the single-monitor method. These two methods were compared in terms of the precision of visual inspection. The single-monitor method was significantly superior to the separate-monitor method in sensitivity and in the magnitude of the discrepancy that could not be detected. The single-monitor method provides higher precision in visual inspection than does the separate-monitor method, and is a useful verification procedure.

A Rail-To-Rail Class-AB Amplifier With an Offset Cancellation for LCD Drivers

A rail-to-rail amplifier with an offset cancellation, which is suitable for high color depth and high-resolution liquid crystal display (LCD) drivers, is proposed. The amplifier incorporates dual complementary differential pairs, which are classified as main and auxiliary transconductance amplifiers, to obtain a full input voltage swing and an offset canceling capability. Both offset voltage and injection-induced error, due to the device mismatch and charge injection, respectively, are greatly reduced. The offset cancellation and charge conservation, which is used to reduce the dynamic power consumption, are operated during the same time slot so that the driving period does not need to increase. An experimental prototype amplifier is implemented with 0.35-mum CMOS technology. The circuit draws 7.5 muA static current and exhibits the settling time of 3 mus, for a voltage swing of 5 V under a 3.4 kOmega resistance, and a 140 pF capacitance load with a power supply of 5 V. The offset voltage of the amplifier with offset cancellation is 0.48 mV.

A New Resolution Enhancement Technology Using the Independent Sub-Pixel Driving for the Medical Liquid Crystal Displays

A new resolution enhancement technology using the independent sub-pixel driving technology was developed for the medical monochrome liquid crystal displays (LCDs). Each pixel of monochrome LCDs, which employ the color liquid crystal panels that its color filters are removed, consists of three sub-pixels. In the new LCD system implemented with this new technology, the sub-pixel intensities were modulated according to the detailed image information, and consequently resolution was enhanced three times. Thus the new technology realized a 15 mega-pixels (MP) super high-resolution LCD (SHR-LCD) out of a conventional 5 MP LCD and a 9 MP SHR-LCD out of a conventional 3 MP LCD. Physical measurements and perceptual evaluations performed in this study proved that the achieved 15 MP (through our new technology) was appropriate and efficient to depict the finer anatomical structures such as the micro calcifications in mammography.

Active and Adaptive Charging Method on Data Lines for Delay Compensation

Charging time is a critical constraint in the design of large-size or high-resolution liquid crystal display. A fast charging method is proposed to generate adaptive charging voltages by comparing the pixel values between previous and current frames. Data line segmentation is also proposed to charge different subpixels on the data line precisely, which is implemented by using operational amplifiers and resistor networks.

High-resolution monochrome liquid crystal display versus efficient household colour liquid crystal display: comparison of their diagnostic performance with unenhanced CT images in focal liver lesions

This study compared the ability of an efficient household liquid crystal display (LCD) and a medical high-resolution LCD to detect small hepatic lesions on unenhanced computed tomography (CT) images. We obtained the images from 100 subjects who had undergone abdominal CT. They consisted of 41 patients with a single space-occupying lesion (SOL) in the liver and 59 control subjects with no SOL. Independently, five radiologists rated their confidence concerning the presence of hepatic SOLs on a continuous scale from 0 to 1. Receiver-operating characteristic (ROC) analysis was performed using the jackknife method using the program LABMRMC. We evaluated the differences in A(z) based on the 95% confidence intervals. The mean A(z) of the five observers was 0.9594 with the efficient household LCD vs. 0.9335 with the medical high-resolution LCD. The difference was -0.0422, and the 95% confidence interval was -0.1101 to 0.0257 (p=0.2203). There was no significant difference in the A(z) value between the two types of LCDs. The diagnostic performance with the household LCD was comparable to that with the high-resolution LCD, implying that the former type of LCD can be used to diagnose CT images.