Laser lift-off mechanism and optical-electric characteristics of red Micro-LED devices.

The removal of a sapphire substrate by laser lift-off, photoluminescence detection technology, and the luminous efficiency of size-dependent devices are very hot issues for the Micro-LED display, which is thoroughly studied in this paper. The mechanism of thermal decomposition of the organic adhesive layer after laser irradiation is analyzed in detail, and the thermal decomposition temperature of 450 °C solved by the established one-dimensional model is highly consistent with the inherent decomposition temperature of the PI material. The spectral intensity of PL is higher, and the peak wavelength is red-shifted by about 2 nm compared to EL under the same excitation condition. The results of size-dependent device optical-electric characteristics show that the smaller the device size, the lower the luminous efficiency under the same display resolution and PPI conditions, and the higher corresponding display power consumption.

Optical-electrical characteristic of green based on GaN micro-LED arrays.

A detailed theoretical derivation and calculation method of the difference coefficient between a light distribution pattern of a 30×20µm2 green micro-LED array and Lambert source is proposed first in this paper, to the best of our knowledge, which establishes an accurate relationship between external quantum efficiency and current efficiency (cd/A). The variation of capacitance with voltage and wavelength blueshift is illustrated by a carrier recombination mechanism. The current efficiency reaches 132.5 cd/A for the 60×50µm2 and 121.7 cd/A for the 25×15µm2 arrays, and the mechanism caused by size dependence is analyzed in detail combined with the classical ABC model.

Full-color micro-LED displays with cadmium-free quantum dots patterned by photolithography technology: retraction.

The referenced article [Appl. Opt.59, 11112 (2020)APOPAI0003-693510.1364/AO.412267] has been retracted by the author.

Full-color micro-LED displays with cadmium-free quantum dots patterned by photolithography technology.

A full-color display consisting of red and green photoluminescence cadmium-free quantum dots (QDs) as the color conversion material and excited by a 68×68 blue micro-LED flip chip array mounted on an active-matrix driving board was completed in this study. The QD photoresist (QDPR) lithography technology was reported in detail, and it has been proven to be a stable process route. The suitable thickness of 12±1µm of the QDPR and black matrix was proposed to reduce the light cross talk between different sub-pixels. The thickness of the common color filter of 1-2 µm was made successfully between the quantum dot film and the cover glass, which can greatly reduce the leakage of blue backlight and decrease the quantum dots excitation by the ambient light, as well as improve the color gamut and color purity of the display panel. In addition, the high red and green light conversion efficiency reaches up to 78.1% and 296.5%, respectively, and the screen display can reach 98.8% NTSC on the CIE 1931 chromaticity. Representative RGB monochromatic pictures were displayed successfully and ≤0.04 viewing angle deviation of the display was measured precisely.

Evaluation of Sialendoscopy-Assisted Treatment of Submandibular Gland Stones.

PURPOSE: The aim of the present study was to evaluate the therapeutic efficiency of sialendoscopy-assisted operations in the treatment of submandibular gland stones. MATERIALS AND METHODS: The data from 8 patients with sialolithiasis who underwent sialendoscopy from August 2015 to January 2016 at the Department of Oral and Maxillofacial Surgery, School of Stomatology, China Medical University (Shenyang, China) were retrospectively reviewed. All the patients had undergone preoperative technetium-99m pertechnetate salivary gland scintigraphy. The results revealed that the salivary glands exhibited normal or slightly reduced uptake and excretion dysfunction. Computed tomography examinations revealed stones located in the intraductal area near the glands or in the branches that could not be removed owing to their deep locations within the mouth. Therefore, an endoscope was inserted, the stones were located intraductally using sialendoscopy, and a transcervical incision was made to remove the stones and preserve the submandibular gland. RESULTS: The stones were completely removed, and the submandibular gland was preserved in all cases. The patients recovered well postoperatively, and no complications developed. CONCLUSIONS: Our results suggest that sialendoscopy-assisted sialolithectomy is an effective and safe surgical technique for the removal of proximal and intraglandular submandibular gland stones. The patients' quality of life had obviously improved postoperatively.

Advantages of submandibular gland preservation surgery over submandibular gland resection for proximal submandibular stones.

OBJECTIVES: This study sought to compare surgical outcomes after the removal of submandibular gland (SMG) stones via 2 different surgical methods. MATERIALS AND METHODS: From June 2015 to July 2016, a total of 40 patients with SMG stones were selected from the Department of Oral and Maxillofacial Surgery, School of Stomatology, China Medical University (Shenyang, China), and were randomly assigned to 2 groups. Twenty patients underwent sialendoscopy-assisted stone removal via extraoral incision with preservation of the SMG, and 20 patients underwent traditional SMG resection. The outcomes of the 2 surgical procedures were assessed. RESULTS: The operation time and hospital stay were shorter in the SMG preservation group than the SMG resection group. There were no significant differences in stone size or location between the groups. The mean visual analog scale (VAS) score was lower in the SMG preservation group than the SMG resection group. All patients in the SMG resection group exhibited varying degrees of scarring and concave deformity on the face and neck, whereas all patients in the SMG preservation group retained intact facial morphology. CONCLUSIONS: Sialendoscopy-assisted stone removal with preservation of the SMG exhibited many advantages relative to traditional SMG resection.