High Refresh Rate Research Articles

Adaptive frequency driving scan driver based on a‐InGaZnO TFTs for extremely low‐power displays

AbstractIn this paper, we propose a novel scan driver combined with a logic circuit using amorphous indium‐gallium‐zinc‐oxide (a‐InGaZnO) thin‐film transistors (TFTs) in order to enhance the electrical stability and reduce power consumption in display panels. The latest mobile displays with high resolution and refresh rates consume more battery power, which inevitably limits portability and usability. The proposed scan driver can mask the signal by combining the output stage with a logic circuit, thereby blocking the output pulse for static images. This allows the display panel to operate in a partial driving mode depending on the display content. Due to the masking of the scan driver's output pulses, the connected pixel circuits are consistently maintained in the same state as the previous frame, leading to a lower refresh rate and reduced power consumption. Furthermore, by constructing additional control signals, the proposed scan driver can operate stably in depletion mode under a ∆VTH = −3 V.

High refresh rate display for natural monocular viewing in AOSLO psychophysics experiments

High refresh rate display for natural monocular viewing in AOSLO psychophysics experiments

Local color display technology

AbstractThe local color display technology utilizes a high refresh rate LCD open‐cell without a color filter and enables color adjustment through independent RGB backlight zones isolated by an anti‐scatter grid (ASG). Synchronized calibration between the open‐cell and the backlight zones is achieved by aligning the backlight controller with the vertical clock pulse (CPV)/vertical start pulse (STV) signals in the open‐cell gate driver, thereby determining the open‐cell scan line position. Once synchronous calibration is completed, the backlight controller refreshes the corresponding RGB backlight zones whenever the open‐cell scan line passes through them. The local color display technology can reduce the cost of open‐cell by 20%, improve resolution by three times, enhance brightness by eight times, expand the color gamut to BT2020, and improve grayscale to 32‐bits.

Immersive and Interactive 3D Visualization of Large-Scale Geoscientific Data

Abstract Virtual reality (VR) technology has great potential in supporting planetary scientists and the field of geosciences by offering immersive and interactive experiences for data exploration and analysis. This paper shows the opportunities presented by the use of VR technology in the geosciences domain while also identifying the open challenges associated with this integration. Our focus is on highlighting the several benefits that VR brings, including stereo vision, head tracking, and collaborative capabilities. These features can foster knowledge exchange and interdisciplinary research. Nevertheless, the adoption of VR presents certain challenges that need to be addressed. These include maintaining high refresh rates, handling large heterogeneous datasets, and striking a balance between visualization fidelity and performance. Fortunately, significant advancements have been made in high-performance data analysis, progressive data streaming, and real-time visualization, enabling interactive exploration of large-scale datasets within VR environments. To support a broader adoption among domain experts, we propose a visualization approach that scales both with display and with data size. As such, the system can be used to interactively explore large-scale datasets in immersive environments like CAVEs or powerwalls, on HMDs, or on traditional desktop setups. This approach allows for seamless transitions between desktop and VR experiences, leveraging immersive environments for collaboration and outreach activities. In this paper, we present an architectural framework, hardware environments, use cases, lessons learned, and the future potential of VR in this field. Through this scalable system, we anticipate transformative advancements in scientific exploration, collaboration, and knowledge dissemination.

PEA-PODs: Perceptual Evaluation of Algorithms for Power Optimization in XR Displays

Display power consumption is an emerging concern for untethered devices. This goes double for augmented and virtual extended reality (XR) displays, which target high refresh rates and high resolutions while conforming to an ergonomically light form factor. A number of image mapping techniques have been proposed to extend battery usage. However, there is currently no comprehensive quantitative understanding of how the power savings provided by these methods compare to their impact on visual quality. We set out to answer this question. To this end, we present a perceptual evaluation of algorithms (PEA) for power optimization in XR displays (PODs). Consolidating a portfolio of six power-saving display mapping approaches, we begin by performing a large-scale perceptual study to understand the impact of each method on perceived quality in the wild. This results in a unified quality score for each technique, scaled in just-objectionable-difference (JOD) units. In parallel, each technique is analyzed using hardware-accurate power models. The resulting JOD-to-Milliwatt transfer function provides a first-of-its-kind look into tradeoffs offered by display mapping techniques, and can be directly employed to make architectural decisions for power budgets on XR displays. Finally, we leverage our study data and power models to address important display power applications like the choice of display primary, power implications of eye tracking, and more 1 .

Perceptual Foundation and Extension to Phase Tagging for Rapid Invisible Frequency Tagging (RIFT)

Abstract Recent years have seen the emergence of a visual stimulation protocol called Rapid Invisible Frequency Tagging (RIFT) in cognitive neuroscience. In RIFT experiments, visual stimuli are presented at a rapidly and sinusoidally oscillating luminance, using high refresh rate projection equipment. Such stimuli result in strong steady-state responses in visual cortex, measurable extracranially using EEG or MEG. The high signal-to-noise ratio of these neural signals, combined with the alleged invisibility of the manipulation, make RIFT a potentially promising technique to study the neural basis of visual processing. In this study, we set out to resolve two fundamental, yet still outstanding, issues regarding RIFT; as well as to open up a new avenue for taking RIFT beyond frequency tagging per se. First, we provide robust evidence that RIFT is indeed subjectively undetectable, going beyond previous anecdotal reports. Second, we demonstrate that full-amplitude luminance or contrast manipulation offer the best tagging results. Third and finally, we demonstrate that, in addition to frequency tagging, phase tagging can reliably be used in RIFT studies, opening up new avenues for constructing RIFT experiments. Together, this provides a solid foundation for using RIFT in visual cognitive neuroscience.

P‐80: 4K Real 240Hz Technology in Large LCD‐TFT TVs

This thesis presents the innovative 4K Real 240Hz technology independently developed by BOE in the realm of large‐scale TFT‐LCD televisions. Addressing the challenges posed by high refresh rates, including motion trailing, reduced charging efficiency, and elevated temperatures in Periphery Line Glass (PLG), we employed advanced technologies such as 2Frame OD (Over Driving), MLC (Multi‐Level Clock), and GPM (Gate Pulse Modulation). Furthermore, we utilized premium materials, including Low GAP Fast Response Liquid Crystals and the ION enhancement process, to craft 4K Real 240Hz products that offer exceptional image quality and swift responsiveness.

55‐1: A Novel Modeling & Compensation Algorithm for Medium‐Term Image Sticking on AMOLED Display

In this paper, we discuss the different type of image sticking(IS) and propose a novel algorithm for improving medium‐term IS on AMOLED display. This method could not only solve the IS effect on traditional display but also the multi‐areas frame rate (MAFR) display.For future OLED power‐saving applications, the application of MAFR becomes increasingly important. This involves categorizing the same display into high and low refresh rate zones based on display usage efficiency. When the display remains static for a period and then switches, the issue of display retention may arise. Our experimental results confirms that IS can be quantified into a model, and the algorithm is used for real‐time compensation to reduce the retention issues.

P‐39: Simulation of Perceived Motion Blur on 480Hz OLED Monitor

Refresh rate is an important specification for gaming OLED monitors. With the development of the gaming industry and the graphics processing unit (GPU), the demand for gaming monitors that supporting high refresh rates is increasing. In this paper, simulation methods for perceived motion blur are proposed to predict the degree of blur according to the refresh rate. Experimental results indicate that the proposed simulation methods are quite effective in predicting the degree of motion blur. In addition, this paper presents the predicted results of blur as the refresh rate increases up to 480Hz.

58‐4: Late‐News Paper: Dynamic MTF Measurements of Gaming Monitors

Recent gaming monitors claim high refresh rates of ≥240 Hz with response times ≤1 ms. However, these temporal metrics do not clearly reveal their true spatiotemporal resolution, which depends on the velocity at which the images are displayed. This is the first study to demonstrate the line‐based dynamic modulation transfer function (MTF) measurement method for comparing the performances of different gaming monitors. A single line was scrolled on the monitors, and a small region of the screen was captured with a high‐speed camera during one display refresh period. The dynamic MTF results elucidate the dependence of spatiotemporal resolution characteristics on the scroll speed, refresh rate, and response time of the monitors.

6‐3: Development of Internal Compensation Technology for Medium Size OLED Display based on Oxide TFTs

To develop the internal compensation for medium size OLED display with high resolution, heavy RC load, and high refresh rate based on oxide TFTs, we employed the pixel of separating compensation and refreshing data, a new PWM‐GOA circuit and a new scan‐GOA circuit. After compensation, the uniformity can be increased from less than 40% to over 80%. We successfully demonstrated 6 inch Panels, which have sufficient stability during operation at 60℃for over 500 hours and 60℃&90% humidity for over 240 hours.

P‐69: Cause Analysis of Water Ripple Issue on Charging‐ratio Sensitive LCD Panels Based on TCON Timing Control Theory

Water Ripple is the fine rolling textures phenomenon that occurs on large size, high resolution and high refresh rate LCD panels. It is a tough issue in the field of high‐end TV. The root cause is that such panels are too sensitive to pixel charging‐ratio. To ameliorate the problem, this paper analyzed the causes of charging‐ratio fluctuation from the perspectives of cross clockdomain conversions, display transport protocols and SSC influence, based on the TCON timing control theory. Then a method was proposed to cover the issue. The results show that at least one or two levels of improvement can be achieved. This study can provide an idea for the solution of water ripple, which is important to actual products.

An active‐matrix microLED display based on monolithic integration with IGZO backplane

AbstractThis paper presents a method of monolithically integrating gallium nitride micrometer‐scale light‐emitting diodes (microLEDs) with an indium gallium zinc oxide (IGZO) thin‐film transistor (TFT) backplane to produce an active‐matrix microdisplay. After discussion of the fabrication process, individual LEDs, TFTs, and the integrated system are characterized. Results demonstrate a 32 × 32 pixel, 78.4 PPI microdisplay with luminance exceeding 1500 nits. The dynamic set and hold behaviors of the active‐matrix pixel circuit are analyzed to verify the applicability of this technology for use in high and low refresh rate displays.

P‐1.18: Research on the Mechanism of Moving Head Pattern Aggravation after Reducing Refresh Rate of Column Architecture with High Refresh Rate

P‐1.18: Research on the Mechanism of Moving Head Pattern Aggravation after Reducing Refresh Rate of Column Architecture with High Refresh Rate

The discrepancy in timing between synchronous signals and visual stimulation should not be underestimated.

Response latency is a critical parameter in studying human behavior, representing the time interval between the onset of stimulus and the response. However, different time between devices can introduce errors. Serial port synchronization signal can mitigate this, but limited information is available regarding their accuracy. Optical signals offer another option, but the difference in the positioning of optical signals and visual stimuli can introduce errors, and there have been limited reports of error reduction. This study aims to investigate methods for reducing the time errors. We used the Psychtoolbox to generate visual stimuli and serial port synchronization signals to explore their accuracy. Subsequently, we proposed a calibration formula to minimize the error between optical signals and visual stimuli. The findings are as follows: Firstly, the serial port synchronization signal presenting precedes visual stimulation, with a smaller lead time observed at higher refresh rates. Secondly, the lead time increases as the stimulus position deviates to the right and downwards. In Linux and IOPort(), serial port synchronization signals exhibited greater accuracy. Considering the poor accuracy and the multiple influencing factors associated with serial port synchronization signals, it is recommended to use optical signals to complete time synchronization. The results indicate that under the darkening process, the time error is -0.23 ~ 0.08 ms (mean). This calibration formula can help measure the response latency accurately. This study provides valuable insights for optimizing experimental design and improving the accuracy of response latency. Although it only involves visual stimuli, the methods and results of this study can still serve as a reference.

Eye-hand coordination all the way: from discrete to continuous hand movements.

The differentiation between continuous and discrete actions is key for behavioral neuroscience. Although many studies have characterized eye-hand coordination during discrete (e.g., reaching) and continuous (e.g., pursuit tracking) actions, all these studies were conducted separately, using different setups and participants. In addition, how eye-hand coordination might operate at the frontier between discrete and continuous movements remains unexplored. Here we filled these gaps by means of a task that could elicit different movement dynamics. Twenty-eight participants were asked to simultaneously track with their eyes and a joystick a visual target that followed an unpredictable trajectory and whose position was updated at different rates (from 1.5 to 240 Hz). This procedure allowed us to examine actions ranging from discrete point-to-point movements (low refresh rate) to continuous pursuit (high refresh rate). For comparison, we also tested a manual tracking condition with the eyes fixed and a pure eye tracking condition (hand fixed). The results showed an abrupt transition between discrete and continuous hand movements around 3 Hz contrasting with a smooth trade-off between fixations and smooth pursuit. Nevertheless, hand and eye tracking accuracy remained strongly correlated, with each of these depending on whether the other effector was recruited. Moreover, gaze-cursor distance and lag were smaller when eye and hand performed the task conjointly than separately. Altogether, despite some dissimilarities in eye and hand dynamics when transitioning between discrete and continuous movements, our results emphasize that eye-hand coordination continues to smoothly operate and support the notion of synergies across eye movement types.NEW & NOTEWORTHY The differentiation between continuous and discrete actions is key for behavioral neuroscience. By using a visuomotor task in which we manipulate the target refresh rate to trigger different movement dynamics, we explored eye-hand coordination all the way from discrete to continuous actions. Despite abrupt changes in hand dynamics, eye-hand coordination continues to operate via a gradual trade-off between fixations and smooth pursuit, an observation confirming the notion of synergies across eye movement types.

Multi-focus manipulation system based on SNES aberration self-calibration

Abstract Wavefront shaping using digital micromirror devices (DMDs) allows inertia-free focus manipulation with numerous modulation modes and high refresh rates. However, the aberration caused by the curvature of DMD affects the focusing performance. Here, we propose an aberration self-calibration method based on separable natural evolution strategies (SNES). This method searches optimal Zernike coefficients of aberration globally and completes compensation using super-pixel encoding. Compared to the genetic algorithm method, we improve the speed by 62% and achieve better-focused spots. It enables simultaneous scanning of 25 independent focal spots. This advancement supports wavefront shaping applications in optical imaging, industrial inspection, and laser processing.

Ray tracing-based construction of 3D background model for real-time stereoscopic rendering of live immersive video

Immersive video stored in multiview video-plus-depth format can provide viewers with vivid immersive experiences. However, rendering such video in real time in immersive environments remains a challenging task due to the high resolution and refresh rate demanded by recent extended reality displays. An essential issue in this immersive rendering is the disocclusion problem that inevitably occurs when virtual views are synthesized via the de facto standard 3D warping technique. In this paper, we present a novel virtual view synthesis framework that, from a live immersive video stream, renders stereoscopic images in real time for a freely moving virtual viewer. The main difference from previous approaches is that the surrounding background environment of the immersive video’s virtual scene is progressively reproduced on the fly directly in the 3D space while the input stream is being rendered. To allow this, we propose a new 3D background modeling scheme that, based on GPU-accelerated real-time ray tracing, efficiently and incrementally builds the background model in compact 3D triangular mesh. Then, we demonstrate that the 3D background environment can effectively alleviate the critical disocclusion problem in the immersive rendering, eventually reducing spatial and temporal aliasing artifacts. It is also suggested that the 3D representation of background environment enables extension of the virtual environment of immersive video by interactively adding 3D visual effects during rendering.

A directionally illuminated pixel-selective flickering-free autostereoscopic display

A directionally illuminated pixel-selective flickering-free autostereoscopic display is proposed and demonstrated. The system consists of the U-shaped backlight, the mix-grooves cylindrical Fresnel lens array, a light shaping diffuser film, and a liquid crystal display with a directional light splitting element. Simulation is applied to obtain the crosstalk and the illuminance distribution at each viewpoint, which serves as design guideline for system structure and component parameters. The simulation and experimental results indicate that directional projection of parallax images is achieved for a high-quality flickering-free autostereoscopic display with a large viewing angle and continuous viewing volume. The crosstalk between left- and right-channels can be controlled down to 5.49%, while the resolution for each eye is more than a full HD. Furthermore, the alternative flickering in high refresh rate directional backlight autostereoscopic displays is removed by the proposed system, resulting in a high-quality and flickering-free viewing experience for multiple users.

Focusing scattering light field with different states based on iterative algorithm

Transmitting optical information through scattering medium has broad application prospects in biomedical, aerospace and other fields. However, the light passing through the scattering medium will cause wavefront distortion and optical information blurring. Wavefront shaping technology uses a mathematical matrix to characterize the characteristics of scattering medium, which can achieve refocusing and imaging after light propagation through the scattering medium. It mainly includes optical phase conjugation, optical transmission matrix and wavefront shaping based on iterative optimization. However, the iterative wavefront shaping is considered to be a cost-effective method. Based on the wavefront amplitude modulation technology, the wavefront amplitude of the incident light is continuously adjusted by using the optimization algorithm to find the corresponding wavefront amplitude distribution that can maximize the light intensity in the target area. The system generates binary patterns implemented with digital-micromirror device (DMD) based on on-off state of micromirror, where “on” represents 1 and “off” refers to 0. The DMD has a high refresh rate and can achieve high speed wavefront amplitude modulation by using the iteration algorithm. In the experiment, the scattering medium is prepared with TiO<sub>2</sub>, water and gelatin, whose persistence times are controlled with the water-gelatin ratio (WGR). In addition, the Pearson correlation coefficient (Cor) curve obtained through 300-s-measurement under different WGR conditions, which shows that the greater WGR, the shorter the persistence time is. The experiment mainly studies the focusing of the spatial light through scattering media by wavefront amplitude modulation, and discusses the ability of point guard algorithm (PGA) and genetic algorithm (GA) to control the scattered light field with different persistence times in 64 × 64 segments. The experimental results show that the PGA can achieve higher enhancement factor and more uniform multi-point focusing than the GA after 1000 iterations in the scattering medium with the same persistence time. The relative standard deviation value is inversely proportional to the WGR value when multi-point focusing can be completed. We also demonstrate that GA can only achieve single-point focusing when WGR = 40, and it cannot accomplish multi-point focusing in self-made scattering medium. This study not only verifies a method to achieve focusing scattering light field, but also provides a new scheme for testing the performance of the iterative wavefront shaping.