Satoshi Miyaguchi

An organic LED display exhibiting pure RGB colors

Abstract A full color 5.2-in. 1/4 video graphics array (VGA) passive-matrix organic light emitting diode (OLED) display has been developed. The display features 320 (×3)×240 pixels with an equivalent pixel size of 0.33×0.33 mm 2 , white peak luminance of over 150 cd/m 2 , and power consumption of 6 W. It uses a cathode patterning method with electrically insulated cathode separators and an RGB emitters selective deposition method with a high accuracy mask moving system. Furthermore, we have achieved pure RGB colors as well as high luminance from the cells by applying the optical interference effects. The display can display high resolution video rate pictures with virtually the same quality as a CRT can offer.

23.3: Distinguished Paper: Red‐Phosphorescent OLEDs Employing Bis(8‐Quinolinolato)‐Phenolato‐Aluminum(III) Complexes as Emission‐Layer Hosts

We have developed high-efficiency, long-lived organic light-emitting diode (OLED) devices by introducing red phosphorescent dopants into bis(8-quinolinolato)phenolato-aluminum(III) complexes. The devices exhibited luminance efficiency of 12 cd/A at CIE color coordinates (0.65, 034). The luminance half-decay lifetime is expected to be over 30,000 hours at an initial luminance of 700 cd/m2. We have successfully incorporated these devices into commercial OLED displays.

5.1: Active Matrix Organic Light Emitting Diode Panel using Organic Thin-Film Transistors

By using organic thin-film transistors with pentacene as the active organic layer, active matrix organic light emitting diode panel has been developed. The number of pixels in the panel is 8 × 8, and each pixel is driven by switching and driving transistors. We confirmed 16 gray scales representation by means of an analog driving method.

Organic LED full‐color passive‐matrix display

— A full-color 5.2-inch 1/4-VGA passive-matrix organic LED display has been developed, adopting selective deposition for the different emitting materials. The display features 320 (×3) × 240 pixels with an equivalent pixel size of 0.33 × 0.33 mm, white peak luminance of over 150 cd/m2, and power consumption of 6 W.

Micropatterning method for the cathode of the organic electroluminescent device

A unique method of micropatterning in the order of microns for an organic electroluminescent (OEL) device has been developed. The method consists of a cathode separator with a reverse tapered or a T-shaped cross section which is formed prior to the deposition of organic layers and metal cathodes. By introducing the cathode separator, a high-resolution OEL display panel with gaps of less than 30 µ m between pixels has been fabricated.

Active Matrix Driving Organic Light-Emitting Diode Panel Using Organic Thin-Film Transistors

We developed an active matrix driving organic light-emitting diode (OLED) panel on a glass substrate using two organic thin-film transistors (OTFTs) per pixel, a switching OTFT and a driving OTFT. The OTFTs are bottom contact structures with the high-dielectric constant gate insulator tantalum oxide (Ta2O5, relative dielectric constant of 23) produced by anodization in ammonium adipate solution and with pentacene as the active layer. The W/L (where W and L are the OTFTs channel width and length, respectively) was 400 µm/10 µm for the switching OTFTs and 680 µm/10 µm for the driving OTFTs. The characteristics of the OTFTs were improved by treating the Ta2O5 surface with hexamethyldisilazane (HMDS), so that the field-effect mobility was 2.0×10-1 cm2 V-1 s-1 and the current on/off ratio was 105. A green phosphorescent dopant, tris(2-phenylpyridine)iridium [Ir(ppy)3], was used for the OLED layer. The panel had 8×8 pixels and the aperture ratio was 27%. We confirmed a 16-gray-scale representation and a luminance of 400 cd/m2.

Red‐phosphorescent OLEDs employing bis(8‐quinolinolato)phenolato‐aluminum(III) complexes as emission‐layer hosts

— We have used bis(8-quinolinolato)phenolato-aluminum complexes as emission-layer hosts in red-phosphorescent OLED devices. This enabled high-efficiency long-lived OLED devices with a simple device structure that does not require a hole-blocking layer. Devices with a red-phosphorescent dopant introduced into a noble bis(8-quinolinolato)phenolato-aluminum complex exhibited a high efficiency of 12 cd/A at CIE color coordinates (0.65, 035) and a long operating lifetime of 30,000 hours or more at an initial luminance of 700 cd/m2. Moreover, triplet-triplet annihilation was reduced in the devices because of the wide emission zone enabled by the complex and the short phosphorescent lifetime of the red-phosphorescent dopant. We have successfully incorporated these red-phosphorescent devices into commercial OLED displays.

Organic LED Full Color Passive-Matrix Display

A full color 5.2 inch 1/4VGA passive-matrix organic LED display has been developed adopting selective deposition for the different emitting materials. The display features 320 (× 3) × 240 pixels with an equivalent pixel size of 0.33 × 0.33 mm2 white peak luminance of over 150 cd/m2 and power consumption of 6 W.