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We fabricated a transmissive one-side-emission organic light emitting diode (OLED) based on a stripe-shaped cathode. The fabricated transmissive OLED whose panel size is 180 × 90 mm2 showed high transmittance of 68% with the luminance ratio of the bright side to the dark side of 70.

We have successfully reduced threshold voltage shifts of amorphous In–Ga–Zn–O thin-film transistors (a-IGZO TFTs) on transparent polyimide films against bias-temperature stress below 100 mV, which is equivalent to those on glass substrates. This high reliability was achieved by dense IGZO thin films and annealing temperature below 300 °C. We have reduced bulk defects of IGZO thin films and interface defects between gate insulator and IGZO thin film by optimizing deposition conditions of IGZO thin films and annealing conditions. Furthermore, a 3.0-in. flexible active-matrix organic light-emitting diode was demonstrated with the highly reliable a-IGZO TFT backplane on polyimide film. The polyimide film coating process is compatible with mass-production lines. We believe that flexible organic light-emitting diode displays can be mass produced using a-IGZO TFT backplane on polyimide films.

We have developed an electrochemical reaction display (ECRD) that can be operated in dual reflective and emissive modes in an entire pixel area of a single device. The ECRD utilizes electrochromic (EC) and electrogenerated chemiluminescence (ECL) reactions. These two electrochemical reactions can be controlled independently by adding a luminescent molecule to a liquid electrolyte of an EC cell with three electrodes. In the reflective mode, the ECRD cell exhibits high reflectance (47%) and high contrast ratio (6:1). In the emissive mode, the cell can show luminescent moving images because of the fast response time (10 ms).

Triplet harvesting is a candidate technology for highly efficient and long-life white OLEDs, where green or red phosphorescent emitters are activated by the triplet-excitons diffused from blue fluorescent emitters. We examined two oxadiazole-based electron transport materials with different horizontal molecular orientation as a triplet-exciton diffusion layer (TDL) in triplet-harvesting OLEDs. The device characteristics and the transient electroluminescent analyses of the red phosphorescent emitter showed that the triplet-exciton diffusion was more effective in the highly oriented TDL. The results are ascribed to the strong orbital overlap between the oriented molecules, which provides rapid electron exchange (Dexter energy transfer) in the TDL.

We have investigated the effects of film thickness, anti-reflective (AR) coating and surface roughness on the optical transparency of silicon carbide (SiC) membrane. Peak transmittances monotonously increased as the thickness decreased. The transmittance at 633 nm for 1.05 micrometers thick SiC membrane adjusted by reactive ion etching was 70%, and increased up to 80% by an AR coating. SiC membrane with extremely smooth surface of 0.12 nm (Ra) has been obtained by polishing, and had peak transmittances of 69% and 80% at 633 nm for 2.0 micrometers and 1.0 micrometers in thickness, respectively. Poly-crystalline (beta) -SiC membrane in the suitable tensile stress range of 0.3 to 2.0 X 108 Pa and with high Young's modulus of 4.5 X 1011 Pa has been prepared by a hot wall type low pressure chemical vapor deposition, and been found to need to have thickness over 0.7 micrometers to maintain sufficient mechanical strength in processing.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Many properties of LPCVD SiC film as X-ray mask membrane have been investigated in detail. The film has an atomic ratio of 1.0 and negligible impurities, and was found to be damage-free to SR X-rays up to 500 KJ/cm2. An integrated transparency of 1.05 μm thick SiC membrane for SR X-rays was measured to be 76%. The interference peak at 633 nm of optical spectrum has given the membrane of around 1.0 μm in thickness the transmittance peak of 70% and increased to more than 80% after an AR coating or planarizations by polishing and etching-back. The attainable transmittance was found to be limited to about 84%, theoretically and experimentally, due to the absorption of the membrane. The peak transmittance of 87% is obtainable by the AR coating on the polished SiC membrane. The internal stress was found to be independent of thicknesses above 0.6 μm and the measured Young's modulus is 4.5×1011 Pa irrespective of the thickness and stress. Some extremely polished (0.1 nm Ra) and all the etched-back membranes studied withstood breakage at the pressure as high as the as-deposited ones. The stress uniformity in 30 mm square of the membrane was found to be ± 10 % by measuring five local stresses with a bulge method.

To improve the efficiency of bend transition in OCB, its anisotropy was analyzed. The transition antiparallel (opposite) to the rubbing direction was significantly fast and this anisotropy remained at low temperatures. We propose two effects of LC shear flow on the anisotropy. Based on a pixel design that takes the anisotropy into consideration, 40% reduction of the initialization voltage in a 3-inch TFT-LCD has been achieved.

Fabrication of electronic devices by printing technique is attracting interest in the expectation of lowering production cost. There is an ongoing work using various printing methods. This paper outlines some of the important aspect of printing in terms of fabricating thin film transistor (TFT) arrays. Appropriate combination of inkjet head and the ink material must be considered. Non-piezoelectric inkjet printing methods, such as ultrasonic inkjet printing and electrostatic inkjet printing are also introduced for fabricating all-solution-processed organic thin-film transistor.

— An ink-jet-printing method applied to the microdeposition of high-viscosity resin, including optimization of phosphor dispersion for light-emitting-diode (LED) packaging was examined for the first time. An ultrasonic ink-jet-printing method was used, in which ink droplets are ejected by a focused ultrasonic beam from a nozzle-less printhead. To fabricate white LEDs, high-viscosity phosphor-dispersed resin was deposited to form an encapsulant dome. Two types of methods to control phosphor sedimentation for color uniformity were examined; one is heating the lead frame during the resin deposition, and the other is hydrophobic surface treatment of the lead frame base enabling the fabrication of a small encapsulant dome. For light direction control, a silicone micro lens was deposited on an encapsulant dome using the ink-jet method. The results show that ultrasonic ink-jet printing is an applicable technique to optimize and modify on-demand optical characteristics of LED devices.