Conventional Display Research Articles

Analysis of irradiation in OptiTouch system with optical detection

As part of the research and development project, a multi-touch multimedia system was implemented, working exclusively on the basis of optical technologies. The model of device with a diagonal of 42” was developed and made with 4K TV image technology and simultaneous detection in near infrared. The control of individual system modules was carried out on RaspberryPi microcomputers without typical operating system. The functionality of a conventional large-format display with unlimited multi-touch, QR code scanner, and a document scanner has been achieved in one housing. Luminance distribution tests were carried out in accordance with ANSI requirements and infrared radiation for detection work.

AC-driven QLED based on far-field effect of Au NPs

As the pixel size continues to shrink, conventional display devices are unable to satisfy the increasing demand. Therefore, a novel light-emitting device has garnered significant attention. This device emitted light under an alternating current (AC) electric field and blocked the injection of external carriers by using the insulating layer. However, at the same time, this approach leads to a reduction in brightness. In this paper, we have realized the performance enhancement of AC-driven QLEDs by incorporating Au NPs of different sizes in PEDOT:PSS. Our investigation reveals that Au NPs of greater size exhibit a notable enhancement of the brightness, rising from 5512 cd/m2 to 7234 cd/m2, representing a substantial increase of approximately 31.2 %. It demonstrates the great potential of the "far-field" effect in AC-driven QLEDs.

Flexible plasmonic display featuring differentiated and localized control over transmission and reflection

Structural colors using metal materials, plasmonic color generation, can confine optical excitation beyond the diffraction limit owing to nanoscale metals with high efficiency in light absorption and scattering. They have several advantages over conventional display technology, including superior resolution and long-term preservation. However, most research on plasmonic color generation has been conducted for the development of static color generation, and dynamic tuning remains a challenging issue. To develop dynamic plasmonic colors, electrochemical, liquid crystal, and electromechanical methods have been proposed; however, there have been limitations in repeatability, flexibility, and scale-up processes. To address these problems, this work proposes a flexible dynamic plasmonic display using dielectric elastomer actuators (DEAs) to isotropically control the interdistance between the metal nanostructures, which can show dynamic coloration without polarization distortion. To replace the expensive and small-scale manufacturing approach, shadow masking and transfer technique with the anodic aluminum oxide (AAO) membrane was applied to realize large-scale and uniformly distributed Au nanodisc array. The differentiated and localized color change in the transmission and reflection modes, such as Janus's face, is realized by proper design of Au nanodisc array on the patterned transparent compliant electrodes formed by silver nanowires and PEDOT:PSS composites. Apparent and locally active color changes appeared in the transmission mode, but almost no color changes were observed in the reflection model by DEA actuation. The proposed system has the potential to activate color filters, cryptographic characters, and next generation display technologies.

Eyebox extension for holographic Maxwellian near-eye display by using a real grating and a virtual grating

The Maxwellian display presents always-focused images to the viewer, alleviating the vergence-accommodation conflict (VAC) in near-eye displays (NEDs). However, the limited eyebox of the conventional Maxwellian display prevents it from wider applications. In this paper, an exebox-extended holographic Maxwellian near-eye display is proposed by using a real grating and a virtual grating. A diffraction grating is used to duplicate multiple beams and produce duplicate viewpoints. A virtual grating phase is added in the hologram to steer the beams and deflect the viewpoints. The proposed method combines a slight steering with a large duplicated eyebox, realizing that the viewpoint position can be flexibly controlled. The optical experiment realizes a 49.2° FOV and 12.1 mm eyebox which contains 5 moveable viewpoints. This proposed system shows good display capabilities and has potential applications.

Strain-Sensor-In-Pixel Technology for Resolution-Sustainable Stretchable Displays.

One of the limitations of stretchable displays is the severe degradation of resolution or the decrease in the number of pixels per unit area when stretched. Hence, we suggest a strain-sensor-in-pixel (S-SIP) system through the adoption of hidden pixels that are activated only during the stretch mode for maintaining the density of on-state pixels. For the S-SIP system, the gate and source electrodes of InGaZnO thin-film transistors (TFTs) in an existing pixel are connected to a resistive strain sensor through the facile and selective deposition of silver nanowires (AgNWs) via electrohydrodynamic-jet-printing. With this approach, the strain sensor integrated TFT functions as a strain-triggered switch, which responds only to stretching along the designated axes by finely tuning the orientation and cycles of AgNW printing. The strain sensor-integrated TFT remains in an off-state when unstretched and switches to an on-state when stretched, exhibiting a large negative gauge factor of -1.1 × 1010 and a superior mechanical stability enduring 6000 cycles, which enables the efficient structure to operate hidden pixels without requiring additional signal processing. Furthermore, the stable operation of the S-SIP in a 5 × 5-pixel array is demonstrated via circuit simulation, implying the outstanding applicability and process compatibility to the conventional active-matrix display backplanes.

Floating depth and viewing angle enhanced integral imaging display system based on a transmissive mirror device

We propose a floating depth and viewing angle-enhanced integral imaging (InIm) display system based on a transmissive mirror device (TMD). The system consists of a 2D display, a micro-lens array (MLA), and a TMD. The light emitted by the proposed InIm display system is reconstructed into a floating 3D image by the TMD, and the floating 3D image has a greater floating depth than the conventional InIm display without sacrificing resolution. The issue of mutual restriction between the floating depth and resolution of the 3D image is solved. The positions of the MLA and the 2D display are reversed through the TMD imaging, which results in an improved viewing range and an improved viewing angle of the floating 3D images. The system expands the floating depth and viewing angle simultaneously without sacrificing resolution. The experimental results prove the feasibility of the proposed system.

P‐135: Towards Passing the Visual Turing Test with Field of Light Displays

Field of Light Displays (FoLDs) promise to allow further increases in realism beyond the limits of conventional 2D displays. While the question of how a conventional display can match the limits of the human visual system has been answered, the same question applied to FoLDs has been given much less attention. In this work, we review a recent acuity‐limited viewer model of resolution at depth for a FoLD display. We validate this model using display simulation. We discuss how this model gives less conservative resolution guidelines than previous models, presenting resolution requirements for passing the visual Turing test.

3‐3: Anamorphic‐XR: Imaging Waveguide Technology for Efficient and Wide Field‐of‐View Near‐Eye Display

A near‐eye display technology, Anamorphic‐XRTM, incorporating imaging waveguides is described. Developed for multiple applications since 2011, unique light manipulation capabilities and highly compact form factors are achievable. Catadioptric anamorphic optics and polarisation management are used to sidestep limitations of conventional VR lens and AR waveguide displays, enhancing performance and manufacturability. Simulations and measurements indicate an achievable specification of 90º field‐of‐view at 60ppd; >2000 nits/lumen; 80% polarised light transmission; and >15mm eyebox at 18mm eye relief from a <4mm thick waveguide. A Hybrid Immersive Display is proposed, combining an anamorphic waveguide with a conventional VR display.

A multifunctional display based on photo-responsive perovskite light-emitting diodes

Current display screens are typically only used for information display, but can have a range of different sensors integrated into them for functions such as touch control, ambient light sensing and fingerprint sensing. Photo-responsive light-emitting diodes (LEDs), which can display information and respond to light excitation, could be used to develop future ultra-thin and large screen-to-body ratio screens. However, photo-response is difficult to achieve with conventional display technologies. Here, we report a multifunctional display that uses photo-responsive metal halide perovskite LEDs as pixels. The perovskite LED display can be simultaneously used as a touch screen, ambient light sensor and image sensor (including for fingerprint drawing) without integrating any additional sensors. The light-to-electricity conversion efficiency of the pixels also allow the display to act as a photovoltaic device that can charge the equipment.

Preparation and Application of Polymer-Dispersed Liquid Crystal Film with Step-Driven Display Capability.

The realization of multifunctional advanced displays with better electro-optical properties is especially crucial at present. However, conventional integral full drive-based transparent display is increasingly failing to meet the demands of the day. Herein, partitioned polymerization as a novel preparation method was introduced innovatively into polymer-dispersed liquid crystals (PDLC) for realizing a step-driven display in agreement with fluorescent dye to solve the above drawback. At first, the utilization of fluorescent dye to endow the PDLC film with fluorescent properties resulted in a reduction in the saturation voltage of the PDLC from 39.7 V to 25.5 V and an increase in the contrast ratio from 58.4 to 96.6. Meanwhile, the experimental observations and theoretical considerations have elucidated that variation in microscopic pore size can significantly influence the electro-optical behavior of PDLC. Then, the step-driven PDLC film was fabricated through the exposure of different regions of the LC cell to different UV-light intensities, resulting in stepwise voltage-transmittance (V-T) responses of the PDLC film for the corresponding regions. Consequently, under appropriate driving voltages, the PDLC can realize three different states of total scattering, semi-transparent and total transparent, respectively. In addition, the PDLC film also embodied an outstanding anti-aging property and UV-shielding performance, which makes it fascinating for multifunctional advanced display applications.

Mechanism of Infiltration between Alumina and Polyurea for Stretchable Patterned Thin Film

Conventional display panels could be replaced by OLED displays, which are a leading and popular technology in display industry. While OLEDs are quite stretchable, they are vulnerable to oxygen and moisture, and currently, there is no proper barrier film that can protect them from these elements while also maintaining high stretchability. In this study, a horizontally patterned organic/inorganic layer that can increase the stretchability of the film while also providing the necessary protection is proposed. The final structure of the thin film will consist of two layers: a stripe-patterned organic/inorganic layer created using area-selective ALD/MLD processes, followed by an organic layer.To achieve the research objectives, the degree of infiltration of the inorganic layer into the organic layer is crucial. In this study, the mechanism behind the generation of the interface layer between alumina and polyurea is investigated. Trimethylaluminum (TMA) and H2O were used as precursors for fabricating alumina by ALD, while 1,4-phenylene diisocyanate (PPDI) and ethylene diamine (ED) were used for fabricating polyurea by MLD. The porous structure of the polymer allows ALD precursors to spread into it. During TMA pulsing on the polymer layer, the degree of infiltration is affected by the type of chemical bond in the polymer. Previous research has shown that TMA precursors are more likely to infiltrate polymers with C=O bonds into the polymer layer. Therefore, polyurea, which contains a carbonyl functional group (-C(=O)-), is suitable for this research. While the conditions for polyurea MLD are fixed, five chamber temperature conditions for depositing alumina were selected: 30℃, 50℃, 70℃, 90℃, and 110℃. Alumina was deposited by ALD on 30nm of polyurea which was deposited on a Si wafer.From X-ray reflectivity (XRR) data, it was observed that three main types of thin films were formed. As the temperature increased, the density and thickness of the alumina layer forming the thin film changed. To verify the change in the alumina thin film, FTIR and XPS were used to compare the peaks representing the bonds of Aluminum and Oxygen.

Proposal for a Display Method for Myocardial Single Photon Emission Computed Tomography Based on Left Ventricular Volume.

Bull's eye view for the display of myocardial single-photon emission computed tomography (SPECT) 3-D perfusion maps does not reflect left ventricular (LV) volume, an important parameter. We created and evaluated a myocardial SPECT display method that reflects the LV volume.Using Digital Imaging and Communications in Medicine data, short-axis slices from the apex to the base were reconstructed and interpolated into 0.5-mm thickness. We obtained the radial lengths at 1° intervals throughout 360°, and calculated the length of the LV long axis and half circumference (1/2 circ). Myocardial perfusion was displayed as 2 ellipsoidal developments that exhibited the left anterior descending coronary artery (LAD) and non-LAD regions. We created a system that can display these processes on a personal computer. Myocardial SPECT data from 526 individuals without heart disease were analyzed. The long axis and 1/2 circ were compared with the body size, LV end-diastolic diameter (LVDd) obtained by echocardiography, and the end-diastolic volume (EDV) obtained by electrocardiogram-gated SPECT analysis. The 1/2 circle correlated with the LVDd and EDV. The images obtained allowed a diagnosis comparable to that made using the conventional coordinate display system.The new myocardial display reflects ischemia and LV volume within a single image, which cannot be achieved with conventional SPECT image display. Additional studies of this display system are required to allow its application to patients with heart disease.

High-brightness hybrid compressive light field display with improved image quality.

Previous LCD-based multiplicative compressive light field (CLF) display has the trade-off between the brightness and the depth of field (DOF). In this paper, we propose a hybrid CLF display using a reflective polarizer and RGB mini-LED panel. By the polarization-multiplexing and the reflector dam (RD) designed on the mini-LED panel, the proposed system can preserve high brightness while enhancing the DOF. Then, a decomposition algorithm is proposed to improve the image quality by depth segmentation and limiting the motion parallax. Compared to the conventional hybrid CLF display, the brightness of the proposed system reaches 348 nits and the reconstruction quality achieves structural similarity index measure (SSIM) improvement by 0.12. The experiments also demonstrate that the proposed method could achieve a higher brightness, larger depth of field, and higher image quality.

Lens array-based holographic 3D display with an expanded field of view and eyebox.

Conventional spatial light modulator (SLM)-based holographic 3D display faces limited field of view (FOV) and eyebox, due to its limited pixel number. In this paper, a lens array is used to expand the FOV and eyebox of an SLM-based holographic display. The hologram is calculated to reconstruct a 3D sub-image array, each sub-image corresponding to a specific perspective of the 3D object. Then, the 3D sub-image array is imaged and magnified by the lens array to integrate to the original 3D image. The FOV is expanded due to the large numerical aperture of the lens, and the eyebox is expanded because the lens array generates multiple viewpoints with a large pitch. The optical experiment realizes a 17.6° FOV and 50 mm eyebox, which contains 4 × 4 viewpoints. Apparent motion parallax is observed through the viewpoint array, which is usually hard to observe in a conventional SLM-based holographic display. The proposed method provides a novel, to the best of our knowledge, way to expand the FOV and eyebox of holographic 3D display without increasing the total pixel number of the SLM.

Status and Challenges of Blue OLEDs: A Review.

Organic light-emitting diodes (OLEDs) have outperformed conventional display technologies in smartphones, smartwatches, tablets, and televisions while gradually growing to cover a sizable fraction of the solid-state lighting industry. Blue emission is a crucial chromatic component for realizing high-quality red, green, blue, and yellow (RGBY) and RGB white display technologies and solid-state lighting sources. For consumer products with desirable lifetimes and efficiency, deep blue emissions with much higher power efficiency and operation time are necessary prerequisites. This article reviews over 700 papers covering various factors, namely, the crucial role of blue emission for full-color displays and solid-state lighting, the performance status of blue OLEDs, and the systematic development of fluorescent, phosphorescent, and thermally activated delayed fluorescence blue emitters. In addition, various challenges concerning deep blue efficiency, lifetime, and approaches to realizing deeper blue emission and higher efficacy for blue OLED devices are also described.

81‐2: Invited Paper: Highly Stretchable Color MicroLED Meta‐Display Without Image Distortion

Recently, rollable and foldable displays have been commercialized based on organic light‐emitting diode (OLED) display technology. The next form‐factor challenge would be the realization of stretchable displays. Though many studies have targeted stretchable OLED displays, they have an intrinsic issue with the inextensible barrier coating. The micro‐LED displays are considered a promising solution for stretchable displays because of their high reliability without the barrier coating. This talk presents a highly stretchable micro‐LED display manufacturing technology with RGB micro‐LED pixels. We designed circuit boards made of the auxetic meta‐material with a Poisson's ratio of ‐1. These auxetic circuit boards provided our micro‐LED displays with high stretchability and distortion‐free images. We designed and developed a meta‐display manufacturing process for mass production, which is highly compatible with the conventional display manufacturing process on polyimide substrates.

85‐3: High‐Transmittance, High‐Resolution Color Filters with Tailored Structures for Micro‐displays

The needs for high‐performances display is increased while electronics have been integrated into various materials. Compared to conventional display, micro‐type displays are required with miniaturized and high‐ intensity performances for various applications, such as AR/VR, smart contact lens. Common light source‐based approach is a simple way to demonstrate the micro‐display with high‐transmittance, high‐ resolution color filters (CFs). Here, we address the requirements for CFs in color and processing aspects. Our CFs minimize the polymer binder to be easily modified the pattern shapes with high‐transmittance. The CF is easily controlled the shape of pattern with high‐resolution (~2μm). This CF is able to be applied various micro‐light sources (μ‐LED, μ‐OLED). Thus, we believe that it would be one of promising solution for micro‐display applications.

Method for characterizing small-spot luminance in medical virtual reality headsets

We present an experimental method that utilizes a conic probe attached to an integrating sphere for characterizing the small-spot luminance of virtual reality (VR) head-mounted displays (HMDs). This allows for the measurement of relative luminance in virtual scenes and the assessment of VR displays for visualizing grayscale medical images. We characterized the relative luminance of the VIVE Pro and Oculus Rift by displaying test patterns with a circular dark spot of varying diameter in the bright field and compared the probe performance with commercially available systems. Compared to a conventional flat-panel display, the results show a significant level of veiling glare in the HMDs using both a customized conic probe with improved optical performance and an advanced imaging photometer. We also found no significant change in the relative luminance response with the probe’s working distance for the HMDs due to their unique optical architecture for near-eye viewing conditions. Our results highlight the issue of high veiling glare in HMDs and the importance of small-spot luminance measurements to adequately evaluate the technical performance of HMDs for emerging medical applications.

3D Shape‐Morphing Display Enabled by Electrothermally Responsive, Stiffness‐Tunable Liquid Metal Platform with Stretchable Electroluminescent Device

Abstract3D displays are of great interest as next‐generation displays by providing intensified realism of 3D visual information and haptic perception. However, challenges lie in implementing 3D displays due to the limitation of conventional display manufacturing technologies that restrict the dimensional scaling of their forms beyond the 2D layout. Furthermore, on account of the inherent static mechanical properties of constituent materials, the current display form factors can hardly achieve robust and complex 3D structures, thereby hindering their diversity in morphologies and applications. Herein, a versatile shape‐morphing display is presented that can reconfigure its shape into various complex 3D structures through electrothermal operation and firmly maintain its morphed states without power consumption. To achieve this, a shape‐morphing platform, which is composed of a low melting point alloy (LMPA)‐graphene nanoplatelets (GNPs)‐elastomer composite, is integrated with a stretchable electroluminescent (EL) device. The LMPA in the composite, the key material for variable stiffness, imparts shape memory property and forms conductive pathways with GNPs enabling rapid electrothermal actuation. The stretchable EL device provides reliable illumination in 3D shape implementations. Experimental studies and proof‐of‐concept demonstrations show the potential of the shape‐morphing display, opening new opportunities for 3D art displays, transformative wearable electronics, and visio‐tactile automotive interfaces.

Sparse holographic imaging for an integrated augmented reality near-eye display.

Diffraction is the main physical effect involved in the imaging process of holographic displays. In the application of near-eye displays, it generates physical limits that constrain the field of view of the devices. In this contribution, we evaluate experimentally an alternative approach for a holographic display based mainly on refraction. This unconventional imaging process, based on sparse aperture imaging, could lead to integrated near-eye displays through retinal projection, with a larger field of view. We introduce for this evaluation an in-house holographic printer that allows the recording of holographic pixel distributions at a microscopic scale. We show how these microholograms can encode angular information that overcomes the diffraction limit and could alleviate the space bandwidth constraint usually associated with conventional display design.