FINETECH JAPAN 2020 Materials for flexible display gain popular
Picture.1 Transparent TFT-LCD |
December 2-4, FINETECH JAPAN 2020 was held in Makuhari Messe. Main topics
in these exhibitions are picked up.
JDI appeals an original transparent TFT-LCD
As regards display module, Japan Display (JDI) appealed a 12.3-inch transparent TFT-LCD (1440 × 540 pixel), and demonstrated way of use, for example transparent partition display.
In this display, polarizer and color filter are not necessary. It's driven by the field sequential driving method using RGB-LED backlights. In short, backlight is turn on alternately at high speed. An original liquid crystal material is used in LC cell. If switch is turn on, liquid crystal becomes to be transparent; as a result, light from backlight is extracted ahead by light scattering.
Its transmittance is relatively high same as 87 %. Brightness, contrast
ratio, and color number are 150cd/m2, 30:1, and 4096 respectively.
NEG demonstrated materials for flexible display
As concerns material for display, Nippon Electric Glass (NEG) provided some topics. One is a flexible OLED using a flexible roll glass "G-Leaf". It's pilot-produced by YU-FIC project. In this device, G-Leaf (t = 50 μm) was used as a conventional substrate and encapsulation substrate. All layers (IZO anode, Ag anode auxiliary electrode, insulation layer, OEL layers, and cathode) were manufactured by the R2R process.
Picture.3 Demonstration of cover glass for foldable display |
Picture.2 OLED using G-Leaf substrates |
Another is a cover glass "Dinorex UTG" for foldable display. It's pilot-produced by the conventional overflow method. Its break strength and curvature radius are 1000 MPa and 1.5 ㎜ respectively. As picture 3, flexibility was sufficient in practical use.
DNP announced transparent electrode film and direct printing technology
On the other hand, Dai Nippon Printing (DNP) appealed new electrode forming technologies. First of all, a new transparent electrode film was introduced as alternative of ITO film. In this film, Cu series material was patterned finely at 1 μm order by an original photolithography method. Its transmittance and seat resistance were 84 % and 1 - 2 Ω/□ respectively. In short, seat resistance is 50 - 100 part of that of ITO film. It's possible to correspond to various plastic films and large size by R2R process, too.
Picture.5 Printed sample of Nano size Ag wire ink |
Picture.4 Demonstration of transparent conductive film (left: new film,
right:ITO) |
Furthermore, the company announced a new direct printing technology. It's
a modification method of the dispenser method. It's possible to directly
print not only planar shape but also 3D shape. Its printing resolution
is L/S = 30 μm order. In the booth, a printed sample using Nano size Ag
wire ink was exhibited. However, its printing time is very slow same as
5 min (a few cm). For this reason, its application is greatly limited,
for example, high added value components. |
