Journal of the Society for Information Display最新文献

Antireflection surfaces are widely used in optical devices (such as vehicle display, solar cells, and architectural glass) to reduce the reflection and increase transmittance. Plasma etching shows great potential in making subwavelength antireflection structures for its advantage of scalable, low-cost, and applicable in flexible substrates. Here, we demonstrate an antireflection nanostructure by O₂ plasma etching on poly (ethylene terephthalate) (PET) substrate without additional corrosive gas species or antireflective coatings. Nanopores on the surface were formed due to the different etching rates of the organic region and silica region of the surface. The solar weighted average transmittance was improved from 91.6% to 94.8% for single-side treated PET with silica antiblocking layer. The transmission increment was attributed to the gradient refractive index of the nanostructured surface due to the elimination of step discontinuity in refractive index. The result shows a highly efficient, eco-friendly, solvent-free, economical, and sputtering target-free method for reducing the reflection and increasing the transmittance of the substrates.

This study developed a technology for a vertical field-effect transistor (VFET) incorporating c-axis aligned crystal oxide semiconductor on a Gen 3.5 glass substrate. VFETs, with a channel length of 0.5 μm, demonstrated stable characteristics with minimal variation, higher on-state current compared with low-temperature polysilicon FETs, and extremely low off-state leakage current. A prototype 513-ppi organic light-emitting diode display that features a red, green, and blue stripe arrangement and includes an internal compensation circuit with a configuration of six transistors and two capacitors was fabricated by harnessing the advantageous features of VFETs. Such a display was previously unattainable with planar FETs. Thus, the developed VFET technology presents a viable pathway for achieving ultrahigh-resolution panels on glass substrates.

In this study, the PEDOT:PSS conductive polymer material was spin-coated on the ITO surface to improve the surface roughness of the ITO and reduce the spikes on the ITO surface, so as to avoid the burning spots generated in the green organic light emitting diode (OLED) when the voltage was applied to light it up. The OLED emitting is successfully survived. Deuterium atoms (isotopes of hydrogen) with heavier atomic weights can strengthen C-D bonds, slow down the kinetic rate for unwarranted chemical reactions, and improve the performance and stability of OLEDs. In this study, deuterated D-Ir (mppy)₃ was employed as the dopant in the emitting layer of green OLED to replace the general Ir (mppy)₃ to improve the optoelectronic properties and extend the lifetime of green OLED. At a constant voltage of 4 V, the initial luminance and half lifetime of general Ir (mppy)₃ doped and deuterated D-Ir (mppy)₃ doped OLEDs are 188.1 cd/m², 7.2 h and 438.3 cd/m², 42.8 h, respectively. It is shown that doping the deuterated D-Ir (mppy)₃ material in the emitting layer has the effect of prolonging the lifetime of OLED. Compared with the general Ir (mppy)₃, the lifetime of deuterated D-Ir (mppy)₃ doped OLED achieved an extension by 5.9 times.

Micro LED is an extremely small-sized LED where each individual LED operates independently, providing high brightness, excellent contrast ratio, wide color gamut, and other outstanding visual characteristics. We have developed the transfer technology for micro LED chips using our proprietary PR (photoresist) expansion technique. This exclusive PR expansion technology, leveraging semiconductor photo processes, enables pitch conversion between micro LED chips and maintains a high level of accuracy in chip transfer at a sub-micron scale. This innovative transfer technology allows for high-density integration of micro LED chips, effectively reducing the cost per chip, and serving as a key driver for rapid growth in the micro LED market.

The cover image is based on the Special Section Paper Next generation personalized display systems employing adaptive dynamic-range compression techniques to address diversity in individual circadian visual features by Sakuichi Ohtsuka et al., https://doi.org/10.1002/jsid.1277

The SID logo is reproduced with permission of the Society for Information Display.

The measured spatial resolution of augmented reality head-mounted displays (AR HMDs) is determined by three components: optics, display, and the rendering pipeline, which includes the anti-aliasing method. Therefore, separating and quantifying the contributions from these components is necessary for evaluating the spatial resolution of AR HMDs. We demonstrate a method for quantifying the contributions from the optical performance and the rendering pipeline on the spatial resolution of AR HMD using point-spread function (PSF) analysis. In this method, an imaging photometer captures a series of rendered scenes on the AR HMD that consist of arrays of spheres of increasing sizes with different anti-aliasing (AA) methods. The contributions from the optics, display, and anti-aliasing methods can be separated, and we find that temporal anti-aliasing (TAA) and multisample anti-aliasing (MSAA) are in good agreement with the performance of no AA. However, fast approximate anti-aliasing (FXAA) results in decreased luminance for smaller rendered targets and a different spatial resolution for larger targets. Finally, we repeated our methods on multiple HMDs and characterized the dependence of the spatial resolution across the field of view. These measurements show significant non-uniformity in the optical contribution to the spatial resolution.

A new flexible low-temperature polycrystalline silicon thin film transistors (LTPS TFTs) on PI substrate with organic ILD layer, island TFT, and TFT channel perpendicular to stress direction was proposed. AMOLED display panel manufactured with organic ILD did not show any visible degradation of panel image after outward rolling cycles of 200,000 at rolling radius of 4 mm or inward folding cycles of 200,000 at folding radius of 1 mm. Another novel structure of TFT with channel perpendicular to stress direction significantly reduced change of threshold voltage of −0.03 V compared with change of threshold voltage of −0.6 V for TFT with channel parallel to stress direction for reliability test of high drain current (HDC) after 100,000 outward-bending cycles at bending radius of 3 mm. After inward-bending cycles of 200,000 at bending radius of 1 mm, reliability test results for TFT device with organic ILD layer showed that change of on-current is 10.07% for hot carrier instability (HCI) test, change of threshold voltage −0.31 V for negative bias thermal instability (NBTI) test, change of threshold voltage −0.24 V for hysteresis test, and breakdown voltage of gate insulator 7.73 MV/cm, respectively, and these performances are similar to those of TFT device with inorganic ILD (SiN_x).

When viewing the mini-LED display screen from a large angle, the seam appearing at the edge of the module can disrupt the uniformity of the entire screen's bright state. This paper studies the formation mechanism of bright and dark seam and color seam from the perspectives of spatial frequency and packaging structure, derives the formula for spatial frequency, analyzes the optical path at the splicing position, and designs a reasonable packaging film structure to solve the color seam.

This 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.

This paper presents an OLED display driver IC with high-gain fast-slew (HGFS) and on-the-fly self-repair (OFSR) circuits for a spatial resolution of WQHD and a frame rate of 120 Hz. The proposed HGFS circuit increases the slewing current of the unity-gain amplifier of the source driver when the input voltage is largely changed, reducing the settling time of the source driver as the resolution and frame rate increase. To enhance image quality by correcting line defects, the OFSR circuit replaces a faulty channel with a spare dummy channel. The OLED display driver IC was manufactured using a 28-nm high-voltage process with 8 V/20 V transistors and has 2880 source drivers for WQHD display. The measurement results indicate a horizontal line time of 2.7 μs with a slew rate of 7.675 V/μs, supporting WQHD resolution and 120-Hz frame rate. The displayed image demonstrates that the vertical line defect has disappeared with the use of OFSR.