High-Definition, Low-Power Consumption Display Achieved with Crystalline Oxide Semiconductor (OS)

Smartphone with IGZO:
(Distributed by NTT DOCOMO, INC. / Manufactured by Sharp Corporation)

SEL develops and prototypes various displays with crystalline oxide semiconductor technology. FETs made with crystalline oxide semiconductor enable high-resolution displays[1].
Our OLED display prototypes, such as our 8K (pixel count 7680×4320) displays, our flexible displays (foldable display®s and multi-displays), touch-sensor-embedded displays, and extremely-high-resolution displays, are characterized by their high resolution and high contrast. There is a high expectation for this technology to be used in the mobile devices.
Liquid crystal displays utilizing the crystalline oxide semiconductor technology can also be made with high resolution, and they are capable of "idling-stop (IDS)1)" driving, reducing eye strain and power consumption.

Our crystalline oxide semiconductor technology is in widespread use across the display industry, an example of which is its adoption in Sharp Corporation's smartphone displays since 2012.

[1] K. Yokoyama et al., “A 2.78-in 1058-ppi Ultra-High-Resolution OLED Display Using CAAC-OS FETs”, SID Symp. Dig. Tech. Pap., 46, 1039 (2015).

OLED Display

8K display

Extremely-high-resolution 8K panels create depth in the picture, enabling a "natural 3D" view. SEL has fabricated 8K displays with various form factors, such as 13.3 inch panels[2], [3] and 8.3 inch panels[4], [5] (smallest 8K OLED display in the world). We will continue to develop this technology for applications such as virtual reality (VR).

▲8.3 inch 8K display
(pixel count 7680 x 4320) [4]

▲Super High-Definition Display (Super Hi-Vision as the next-generation TV standard)
13.3-Inch 8K Display (pixel count of 7680 × 4320)[3]
*The panel is displaying an 8K, 60Hz video content

 8.3 in
(world's smallest 8K OLED display)
13.3in 8K display
Display size8.3 inch13.3 inch
Effective pixel count7680 (H) × 4320 (V) (8K)7680 (H) × 4320 (V) (8K)
Pixel density1058 ppi664 ppi
DriverGD: on-panel SD:COGGD: on-panel SD:COG
Frame frequency60 Hz60 Hz/120Hz
Coloring methodWhite tandem OLED (top emission)
+color filter
White tandem OLED (top emission)
+color filter

[2] S. Kawashima et al., “13.3-in. 8K x 4K 664-ppi OLED Display Using CAAC-OS FETs”, SID Symp. Dig. Tech. Pap., 45, 627 (2014) , Received SID Distinguished Paper Award.
[3] R. Yamamoto et al., “13.3-inch 8k4k 664-ppi 120-Hz 12-bit OLED Display”, SID Symp. Dig. Tech. Pap. 47, 53 (2016), Received SID Distinguished Paper Award.
[4] M. Shiokawa et al., “A 1058 ppi 8K4K OLED Display Using a Top-Gate Self-Aligned CAAC Oxide Semiconductor FET”, SID Symp. Dig. Tech. Pap. 47, 1209 (2016).
[5] T.Aoyama et al., “An 8.34-inch 1058-ppi 8K x 4K Flexible OLED Display”, SID Symp. Dig. Tech. Pap. 48 [1], 338 (2017).

High-resolution display for AR/VR use

Our OLED display prototype realized the highest level* of pixel density in the world using OSLSI® technology.

▲5000ppi OLED display [6]
Screen Diagonal0.28 in.
Resolution1280 × 720 (HD)
Pixel Density5291 ppi
Frame Frequency120 Hz
Coloring MethodWhite OLED + Color Filter
Emission TypeTop Emission
Source DriverExternal
Scan DriverIntegrated

* According to our research in 2019
[6] S. Katsui et al. “5291 ppi Organic Light Emitting Diode Display using Field-effect Transistors Including a C-Axis Aligned Crystalline Oxide Semiconductor”, SID Symp. Dig. Tech. Pap., 50, 311 (2019) ), Received SID Distinguished Paper Award.

foldable display®

▲Demonstration Video of Foldable Display

▲8.7-Inch Tri-fold Display with Touch Sensor[7]
Image provided by Getty Images

▲13.3-Inch 8K Bi-fold Display (pixel count of 7680 × 4320)[8]
[7] K. Watanabe et al., “An 8.67-in. Foldable OLED Display with an In-cell Touch Sensor”, SID Symp. Dig. Tech. Pap., 46, 246 (2015).
[8] K. Takahashi et al., “13.3-inch 8k4k 664-ppi Foldable OLED Display Using Crystalline Oxide Semiconductor FETs”, SID Symp. Dig. Tech. Pap., 46, 250 (2015).


Small flexible panels with transparent bezels, expanding the possibility of displays

[9] D. Nakamura et al., “An 81-in. 8k x 4k OLED Kawara-Type Multidisplay that Provides a Seamless, Continuous Image”, SID Symp. Dig. Tech. Pap., 46, 1031 (2015).

▲Mockup of a display unit on the dashboard of a car (3 panel units)

Liquid Crystal Display

A combination of a reflective LCD and IDS driving eliminates the backlight, enabling extremely low power consumption. This can enable an ideal e-reader that has a long battery life and is easier on the eyes.

▲5.9-Inch Touch-Sensitive Reflective Display (pixel count of 1536 × 2048)[10]
Image provided by Getty Images

[10] D. Kubota et al., “Reflective LCD with High Reflectance and Color Reproductivity for Reduced Eye Strain”, SID Symp. Dig. Tech. Pap., 46, 1084 (2015).

1) Idling-Stop (IDS) Driving Technology
IDS driving is a display method for still images, utilizing a feature that a video signal can be held by crystalline OS. In a typical display, over 60 images are displayed per second, which are perceived as a single image or a moving image with human eyes. In other words, many images are actually displayed at high speed to display one still image. With the IDS driving, the number of times an image is re-written while displaying a still image can be reduced to, for example, once every 5 seconds. It is like looking at a natural object or at information on paper. Moreover, when this technology is used in a reflective display, a backlight becomes unnecessary, which enables ultra-low power consumption. This technology provides an electronic book reader with ideal functions such as eye-friendly and long-time driving.

* OSLSI and foldable display are registered trademarks of Semiconductor EnergyLaboratory Co., Ltd.
(Japanese trademark registration No. 5698906 and No. 5680115).