Search

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 previously reported a large, seamless, Kawara-type multidisplay formed by overlapping flexible organic light-emitting diode panels, each with two transparent edges. The multidisplay reported in this study creates a more seamless image because of the inclusion of a circular polarizer combined with a flexible panel using an optically isotropic film.

A prototype of an 8.34 inch, 1058 ppi 8K4K display is fabricated. This display shall use top-gate self-aligned-type crystalline oxide semiconductor field-effect transistors as the backplane, and will be the smallest 8K display in the world.

We devised a threshold voltage compensation pixel circuit using back-gate bias voltage. Variation in threshold voltages can be reduced to 10% in simulation while improving the saturation characteristics of a driving transistor. The pixel circuit can compensate not only threshold variation but also mobility variation. We fabricated a 5.29-in Quad-VGA organic light emitting diode display using this pixel circuit.

A prototype 13.3-inch 8k4k 664-ppi high-resolution foldable organic light emitting diode display is constructed. C-axis aligned a-b-plane-anchored crystal In–Ga–Zn oxide field effect transistors designed using a 1.5-µm rule process are used in the backplane. Each pixel circuit has three transistors and one capacitor, and an external circuit is used to correct pixel current.

We established a fabrication process of flexible displays, adopting a transfer technology using an inorganic tungsten-separation-layer. Our separation process requires physical force and water. Tungsten oxide over tungsten in the separation layer plays a key role in separation: water injection into the tungsten oxide reduces the force necessary for separation. In this study, we describe the apparatus we built for the fabrication process of flexible displays. This apparatus fabricated an 8k (7680 × 4320 effective pixels) flexible organic light-emitting diode display.

We fabricated a Kawara-type multidisplay, providing a seamless image by precisely arranging 13.5-in. organic light-emitting diode flexible panels with transparent edges on two adjacent sides. To make overlapping portions less visible, the transparent regions were adjusted optically and corrected in luminance and chromaticity. We used 36 panels to fabricate an 81-in. 8 K organic light-emitting diode Kawara-type multidisplay.

A kawara-type multidisplay providing a seamless, continuous image was fabricated by precisely arranging 13.5-inch organic light-emitting diode (OLED) flexible panels with transparent edges on two adjacent sides. By using 36 panels, an 81-inch 8k4k OLED kawara-type multidisplay, the world's largest display, was fabricated.

We devised a threshold voltage compensation pixel circuit using back-gate bias voltage. Variations in threshold voltage can be reduced to 10% while improving the saturation characteristics of a driving transistor. We fabricated a 5.29-in Quad-VGA OLED display using this pixel circuit.

We established a manufacturing process of flexible displays, adopting a transfer technology using tungsten separation layers. We performed separation with water. In this study, we describe the apparatus we built for the manufacturing process. This apparatus fabricated an 8k (7680 × 4320 effective pixels) flexible organic light-emitting diode display.

A prototype 13.3-inch 8k4k 664-ppi high-resolution foldable OLED display is constructed. C-axis aligned crystalline In—Ga—Zn oxide (CAAC-IGZO) FETs designed using a 1.5-µm rule process are used in the backplane. Each pixel circuit has three transistors and one capacitor, and an external circuit is used to correct pixel current.

In this study, a 5.9-inch foldable active-matrix organic light emitting diode (AMOLED) display was developed. A folding test was performed repeatedly. The display survived the folding test (100,000 folds) with a curvature radius of 2 mm. To protect an organic light emitting diode (OLED) against moisture, inorganic passivation layers are provided on the upper and lower sides of the flexible display. Using our transfer technology, high density passivation layers can be obtained. The measured water vapor transmission rate of the layer is 7 × 10−6 g/m2⋅day or less, which improves OLED reliability. With these techniques, we have developed a book-type display, which is repeatedly foldable like a book, and a tri-fold display including a display area, which is foldable in three.

In this study, white organic electroluminescent devices with microcavity structures were developed. A flexible high-resolution active-matrix organic light-emitting diode display with low power consumption using red, green, blue, and white sub-pixels formed by a color-filter method was fabricated. In addition, a side-roll touch display was developed in combination with a capacitive flexible touch screen.

We have built a prototype of a 13.3-inch 8k4k OLED display. The pixel density is 664 ppi. This display contains about 500,000,000 transistors and scan drivers integrated. We use c-axis aligned crystalline oxide semiconductor (CAAC-OS) FETs in the backplane of this display.

A folding screen type OLED display was developed (Fig. 1) to demonstrate the application of a flexible display. The display surface can be bent with a curvature radius of 4 mm To protect an OLED against moisture, inorganic passivation layers are provided on the upper and lower sides of the flexible display. Using our transfer technology, dense passivation layers can be obtained The measured water vapor transmission rate of the layer is 7 × 10−6 g/m2.day or less, which improves OLED reliability.

In this study, a 5.9-inch foldable Book-Type AMOLED display was developed. A folding test was performed repeatedly. The display survived the folding test (100,000 folds) with a curvature radius of 2 mm.

In this study, white organic EL devices with microcavity structures were developed. A flexible high-resolution AMOLED display with low power consumption using RGBW sub-pixels formed by a color filter method was fabricated. In addition, side-roll and top-roll panels with bezels that are not viewable from the front were also developed using the flexible AMOLED display.

We developed a high-performance 3.4-in. flexible active-matrix organic light-emitting diode (AMOLED) display with remarkably high resolution using an oxide semiconductor in a backplane, by applying our transfer technology that utilizes metal separation layers. Using this panel, we also fabricated a prototype of a side-roll display for mobile uses. In these AMOLED displays, a white OLED combined with a color filter was used in order to achieve remarkably high resolution. For the white OLED, a tandem structure in which a phosphorescent emission unit and a fluorescent emission unit are serially connected with an intermediate layer sandwiched between the emission units was employed. Furthermore, revolutionary technologies that enable a reduction in power consumption in both the phosphorescent and fluorescent emission units were introduced to the white tandem OLED.

We succeeded in developing a deep blue fluorescent OLED exhibiting extremely high external quantum efficiency and a long lifetime by adopting an amine-free material to the hole transporting layer. We have also developed a CAAC-IGZO-FET OLED display with a narrow driver area using this deep blue device.

We have fabricated a 13.5-inch top-emission OLED display including an oxide semiconductor FET element. This display has a high pixel density exceeding 300 dpi and is applicable to a Quad-HDTV (number of pixels: 3840 × RGB × 2160). There have been few reports on fabrication of OLED displays with such a high pixel density so far. Color display is achieved by combining an EL element having a tandem structure and emitting white light with a microcavity structure and a color filter.

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.

A reflection type poly-Si TFT LCD having integrated digital driver comprising CMOS structure has been fabricated with 7 masks by using the CG Silicon technology in order to prove low cost production. The details of a novel circuit structure and CG Silicon process, adopted here, will be mainly described.