Journal of the Society for Information Display最新文献

OLEDoS displays hold great promise for AR/VR applications, but the ultra-high pixel density required for microdisplays, exceeding several thousand PPI, presents significant challenges for pixel circuit design. Above all, the maximum OLED current of each OLEDoS sub-pixel is extremely low, on the order of several nanoamperes or less, resulting in a data voltage range narrower than a few hundred millivolts. Consequently, for example, when expressing 10-bit grayscale, designing data driver circuits to divide the data voltage range into 1024 levels becomes exceedingly challenging. Furthermore, circuit techniques that compensate for variations in transistor characteristics are nearly inapplicable due to the ultra-small pixel area. This paper proposes a pixel circuit design method to expand the data voltage range for a 4670-PPI OLEDoS display while considering current uniformity. The effectiveness of the proposed pixel circuit was verified through measurements on 40 × 120 pixel arrays fabricated in a 5 V 0.13 μm CMOS process.

Due to the limitation of materials, PIC cannot achieve large magnitude phase modulation in a small size, and lacks the reconfigurable ability. Because of its birefringence characteristic, liquid crystal can be used in the liquid crystal on silicon (LCoS) device to achieve a large amount of phase modulation in a small size and has the capacity of reconstruction. Based on the experimental results of LCoS devices and basic liquid crystal waveguide devices, the liquid crystal waveguide device is prepared. While retaining the LCoS spatial optical phase modulation capability, the liquid crystal waveguide and phase modulation capability are realized. The beam splitter, optical switch, and Mach–Zehnder interferometer structure are constructed, which verifies the feasibility of the liquid crystal waveguide phase modulator.

Quantum dot light-emitting diodes (QD-LEDs) have received significant attention as a next-generation display technology aimed at large-size panel production with lower manufacturing costs and excellent picture quality. Here, we demonstrated all-inkjet-printed 12.4-in. full-color QD-LED display with the 182-ppi resolution. The efficiency and lifetime of inkjet-printed QD-LEDs were improved through the ligand exchange of Cd-free quantum dots (QDs), red and green InP and blue ZnSeTe QDs, and optimal control of ink formulation. Dual ligands enhanced colloidal stability and carrier transport properties. The introduction of appropriate additives in the mixed solvent system improved the inkjet processibility and the morphology of inkjet-printed layers.

The gamut ring Intersection diagram extends the gamut ring diagram by representing how the color gamut of a test device covers a reference color gamut. The means of calculating and rendering a gamut ring intersection diagram will be provided and advantages demonstrated through analysis of synthetic and measured display gamuts.

We are introducing an innovative organic semiconductor electroluminescent device capable of emitting light with unprecedented characteristics, that is, high directionality with divergence angle of 1.1° and high color purity with the full-width at half-maximum of 2.5 nm. This achievement was realized through design techniques aimed at enhancing gain via meticulous recombination zone control and complemented by the reduction of the optical losses. These results demonstrate the simultaneous achievement of a narrow spectrum and high directionality in an organic electroluminescent device.

Video see-through (VST) head-mounted displays (HMDs) reconstruct the physical world using outward-facing cameras and depth sensors. One of the major challenges for VST HMDs is the geometric distortion of the physical pass-through content. In this study, we present the experimental setup and metrology for VST geometric distortion measurement on single-camera and dual-camera VST HMDs. The VST geometric distortion is compared to the digital distortion by the HMD. Finally, we investigate the impacts of camera misalignment and depth distance on VST geometric distortion without and with angular-based distortion correction. The results demonstrate that camera misalignment with respect to the eye position is the primary root cause for the distortion. Dual-camera setup is necessary to minimize the VST geometric distortion by placing the cameras close to the eye positions. Although distortion correction can partially mitigate VST geometric distortion in a 2D plane, it remains a challenge for VST distortion correction at multiple depth distance in the 3D space. The method and findings presented of this study may provide guidelines for evaluation of spatial accuracy on VST HMDs and hardware design.

This paper reported on the development of a Mura-free and high precise printing to realize high-resolution organic light-emitting diode and quantum dot light-emitting diode display panels with a G8.5 glass substrate. To realize Mura-free printing, we developed the single-path print line head and the new pixel volume adjustment system with a pixel volume variation of ±0.8%. And to realize high precise printing, we developed the G8.5 table system that compensated for the drop position by changing the jetting time of each nozzle. And verified a drop position accuracy of ±2.1 μm. By combining these technologies, we achieved Mura-free 220-ppi printing on the G8.5 table.

Pancake lens has been widely used in virtual reality (VR) and mixed reality (MR) due to its compact form factor. However, using a half mirror (HM) to fold the optical path results in a tremendous optical loss. To enhance the optical efficiency while keeping a compact form factor, we present a new folded optical system incorporating a nonreciprocal polarization rotator. In our proof-of-concept experiment using a commercial Faraday rotator (FR), the theoretically predicted 100% efficiency is validated. Besides, the angular response of terbium gallium garnet (TGG) material is simulated for the first time and the results indicate that such an FR is relatively insensitive to the incident angle, which can dramatically enhance the contrast ratio of our pancake design. Finally, the potential application of such pancake optics for ultracompact near-infrared (NIR) night vision goggles is also discussed.

Folded optical path designs have been widely applied in Virtual Reality (Pancake VR) displays in recent years. Compared with the traditional straight-through and Fresnel optical path design, the Pancake design has obvious advantages in smaller size and clearer virtual image. However, the Pancake optical path uses polarization devices to fold the optical path and, light undergoes multiple refractions and reflections between lens groups, thus inevitably introducing stray light. This stray light greatly reduces the contrast ratio even if taking high-contrasting Mini-LED backlight LCD as panel, and seriously affects the user experience. In this paper, we first analyze the causes of stray light in the Pancake design and then propose an effective optical design method. In addition, an effective process scheme for improving image contrast is proposed by analyzing the impact of lens and tube reflectivity. Further, a prototype of the Pancake VR optical module is successfully implemented with low stray light and high contrast ratio.

The thermally activated delayed fluorescence (TADF) or phosphorescence-sensitized organic light-emitting diodes (OLEDs) based on multi-resonance TADF (MR-TADF) emitters are greatly studied to develop an effective narrowband emitting system for wide color gamut display applications. However, developing pure green OLEDs to meet BT2020 and NTSC requirements is challenging. In this study, we investigated the TADF and phosphorescence-sensitized OLEDs based on two green MR-TADF final emitters, namely, BpIC-DPA and BpIC-Cz. The unique molecular structure of these emitters resulted in a pure green emission with narrow full width at half-maximum (FWHM) and high PLQY in both solution and solid state. Notably, under optimal conditions, the BpIC-Cz-based OLEDs demonstrated a maximum external quantum efficiency (EQE_max) of 25.7% with alleviated efficiency roll-off characteristics even at high luminescence (EQE_{5000 nits} = 22.6%). The corresponding CIE coordinates are almost at the level of BT2020 and NTSC green-color industrial standards. Additionally, the BpIC-Cz-based device displayed remarkable stability as seen by a noticeably longer device lifetime (LT₉₀) of 25.3 h at a high initial luminance of 5000 nits.