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We have successfully fabricated an 8.34-inch 1058-ppi 8K x 4K flexible organic light-emitting diode (OLED) display. It exhibits the world’s highest resolution and pixel density among flexible OLED displays, offering excellent viewing-angle characteristics owing to the arrangement of subpixels in a zigzag pattern.

We have successfully fabricated a 2.78-in 1058-ppi flexible OLED display. This display exhibits the highest pixel density in the world among flexible displays using thin film transistors. The display can be bent with a curvature radius R = 1 mm and shows a high resistance.

We report a 300mm × 360mm flexible FET substrate made by our transfer technology and 3.4-inch full-color AMOLED display with oxide FET flexible substrate. Our transfer technology has advantages in applicability for a large-size substrate and cost performance because laser irradiation is not needed.

Lasing from a dye-doped cholesteric liquid crystal (CLC) has been studied in cells with a single-output window. One of the glass substrates of the cells was coated with a polymeric CLC film having a high reflectance for laser emission or an aluminum layer for reflection of both pump and lasing beams. Laser emission toward one direction was observed with enhanced intensity.

We developed a high-sensitivity GaN photocathode that works in transmission mode. It has 40.9 % quantum efficiency at 310 nm wavelength. Conventional GaN photocathodes, both transmission mode and reflection mode, are made on a sapphire substrate using metal-organic vapor phase epitaxy (MOVPE). In reflection mode, a GaN photocathode has very high quantum efficiency (QE) of over 50 %. However, in transmission mode, the quantum efficiency of a GaN photocathode was about 25 % at 240 nm with this technique. Therefore, we developed a new GaN photocathode using a glass-bonding technique, where a GaN thin film was bonded to a glass face plate. We found out that constituting an Al- GaN layer on the light incidence side of the photocathode surface provided higher QE than a sole GaN layer type for transmission mode. We focused on the band bending of the photocathode, and analyzed QE for both transmission mode and reflection mode. We then verified the effectiveness of the AlGaN layer using the results from the analysis. The high-sensitivity UV photocathode will be used for flame detection, corona discharge observation, and other UV imaging.

We focused on the off-state current (I off) of oxide semiconductor thin film transistors (TFT) (In–Ga–Zn-oxide TFTs), which is lower than that of amorphous silicon TFTs and successfully made a prototype of a 6.0-in. extended graphics array (XGA) reflective liquid crystal display (RLCD) panel integrally including a data selection demultiplexer and a scan driver and capable of displaying still images at 1/180 fps. When still images are displayed, the frame frequency can be set low. This means that the frequency of rewrites of image data is markedly reduced. This leads to the reduction in the power consumption of an LCD panel. Our panel can solve the problems of electronic paper displays: high drive voltage and difficulty of displaying moving images. Thus, our panel is suitable for electronic paper displays.

We have succeeded in fabricating monodomain polymer cholesteric liquid crystal (PCLC) films by spin coating a polymer solution onto glass substrates with polyimide coated and rubbed unidirectionally. The thickness and helical pitch were well characterized by controlling the rotational speed of the spin coater and the chiral unit content of the polymer solution, respectively. Lasing from dye-doped PCLC films utilizing the photonic structure was confirmed.