A 3.0‐in. 308‐ppi WVGA AMOLED with a top‐emission white OLED and color filter

Shin

2016

Jpn. J. Appl. Phys.

A new structure for white organic light-emitting diode (OLED) displays with a patterned quantum dot (QD) film and a long pass filter (LPF) was proposed and evaluated to realize both a high color gamut and high optical efficiency. Since optical efficiency is a critical parameter in white OLED displays with a high color gamut, a red or green QD film as a color-converting component and an LPF as a light-recycling component are introduced to be adjusted via the characteristics of a color filter (CF). Compared with a conventional white OLED without both a QD film and the LPF, it was confirmed experimentally that the optical powers of red and green light in a new white OLED display were increased by 54.1 and 24.7% using a 30 wt % red QD film and a 20 wt % green QD film with the LPF, respectively. In addition, the white OLED with both a QD film and the LPF resulted in an increase in the color gamut from 98 to 107% (NTSC ratio) due to the narrow emission linewidth of the QDs.

Section: Introductionmentioning

confidence: 99%

Optical efficiency enhancement in white organic light-emitting diode display with high color gamut using patterned quantum dot film and long pass filter

Shin

2016

Jpn. J. Appl. Phys.

Int. J. of Precis. Eng. and Manuf.-Green Tech.

“…Owing to these advantages, OLED has drawn much attention for the next-generation displays. [1][2][3] Although most display companies produce OLED screens, the OLED's market share in the overall display industry is still limited. This is attributed to the fact that the production costs are currently too high to economically develop larger screen sizes.…”

Section: Introductionmentioning

confidence: 99%

Laser micromachining of permalloy for fine metal mask

Heo

Min

Lee

2015

We show that crack-free drilled structures with 25 µm hole size can be fabricated in the 12 µm-thick Permalloy foil by a nanosecond ultraviolet laser with low pulse energy and high repetition rate. The number of pulses required for drilling decreased with increasing pulse energy. The obtained hole exhibited a smaller size than the laser spot, implying that only the central part of a focused Gaussian beam contributed to the drilling. Debris and burr incurring as a result of the laser micromachining could be quickly removed by etching in an HCl/HNO 3 solution. This made it possible to obtain a clear structure without any debris remaining on the foil. This laserdirect process may be effectively utilized for fabricating fine metal masks necessary for the production of organic light emitting diode displays and other electronic devices.

“…For instance, the white OLED using the color-filter approach is seen as perhaps the only practical method to achieve very high resolution (>300 ppi) OLED displays because the color filters can be formed by conventional high-resolution lithography techniques. 5 Also, white OLEDs allow for the use of narrow-band color filters to achieve color gamut greater than 100% of the area of the NTSCxy triangle. Although patterned RGB OLED displays have been shown with 100% NTSC ratio, this requires additional technology, such as the use of microcavity techniques to sufficiently narrow the RGB emission bands to achieve high color purity.…”

Section: Introductionmentioning

confidence: 99%

Fluorescent‐based tandem white OLEDs designed for display and solid‐state‐lighting applications

Spindler¹,

Hatwar²

2009

J Soc Info Display

Abstract— Highly efficient tandem white OLEDs based on fluorescent materials were developed for display and solid‐state‐lighting (SSL) applications. In both cases, the white OLED must have high power efficiency and long lifetime, but there are a number of attributes unique to each application that also must be considered. Tandem OLED technology has been demonstrated as an effective approach to increase luminance, extend OLED lifetime, and allow for use of different emitters in the individual stacks for tuning the emission spectrum to achieve desired performance. Here, examples of bottom‐emission tandem white OLEDs based on small‐molecule fluorescent emitters designed for displays and for SSL applications are reported. A two‐stack tandem white OLED designed for display applications achieved 36.5‐cd/A luminance efficiency, 8500K color temperature, and lifetime estimated to exceed 50,000 hours at 1000 cd/m2. This performance is expected to meet the specifications for large AMOLED displays. A two‐stack tandem white OLED designed for SSL applications achieved 20‐lm/W power efficiency, 38‐cd/A luminance efficiency, 3500K color temperature, and lifetime estimated to exceed 140,000 hours at 1000 cd/m2. With the use of proven light‐extraction techniques, it is estimated that this tandem device will exceed 40 lm/W with more than 500,000‐hour lifetime, performance that should be sufficient for first‐generation lighting products.