Session Index

A flexible CMOS inverter comprising a p-channel SnO and an n-channel IGZO thin-film transistors was fabricated on a polyimide substrate. This inverter exhibits a noise margin high, noise margin low, and static voltage gain of 4.8 V, 4.2 V, and 346 V/V, respectively, at a supply voltage of 10 V.

  Preview abstract

We proposed a concept of switchable projection system for transparent display applications. The projection screen consists of a polarization-sensitive optical diffuse based on broadband cholesteric liquid crystal (CLC) and a polarization-modulator (PM) made of a linear polarizer, a twisted nematic liquid crystal (TNLC), and a quarter-wave plate. Such a projection system is able to switch between transparent and reflective states and provides high display quality with wide viewing angle and high contrast ratio.

 

This research and development can use light fields and electric fields to change the transmittance of smart windows. Photochromic dichroic dyes will change the window to a dark state when exposed to sunlight. The doped cholesteric liquid crystal can be switched from a transparent state to a scattering state through a voltage bistable state. And can switch four different states, transparent, scattering, dark transparent, and dark scattering. In the absence of applied voltage, each state is stable. This smart window can automatically adjust the penetration and can be manually adjusted to meet the needs of privacy.

 

An efficient blue phosphorescent organic light emitting diode, exhibiting turn on voltage of 2.8 V, current efficiency of 58.6 cd/A, power efficiency of 52.7 lm/W and external quantum efficiency of 27.5%, was demonstrated by using a host, based on carbazole and acridine (Ac) moieties as hybrid donor and benzimidazole moiety as acceptor. Ac featuring electron donating capability was thereby incorporated into donor segment to modify the energy level for improvement of hole transport in OLED. As a consequence, highest occupied molecular orbital (HOMO) of new host was approximately 5.4 eV, leading to low turn on voltage (< 3 V).

 

We report on a fast and multi-domain photo-alignment technique based on Digital Light Processing (DLP) system to pattern a complex photo-alignment image without expensive photomasks. This technique has great potential to fabricate some optical writing components such as security cards and liquid crystal grating.

  Preview abstract

Due to the limited field-of-view of cameras, automatic optical inspection for large-size or curve displays with a single camera needs to be equipped with a motorized railing system. In order to keep to normal imagery, the movement range of the camera as well as the rail length is proportional to the panel size. In this work, we took an alternative scenario with camera rotation and geometric transformation via algorithms to increase the field-of-view of the system. Proposed algorithm was successfully demonstrated to register pixelwise illuminance of a commercial display at different camera panning angles.

 

This study applies color sensor and color correction for medical display monitor auto brightness. The results show that in the selection of training samples, factors such as the uniformity of the chromaticity and brightness distribution, how the samples are designed, etc., will have an impact on the calibration results.

  Preview abstract

We reported a linear polarization rotator that is based on single-substrate-liquid crystal polymer film fabricated by spin coating technique. Such a linear polarization rotator operated at the first order of Gooch-Tarry condition exhibits incident-angle independence in a specific angle range.

 

An approach to modulate the bandwidth of reflection light of chiral azobenzene-doped cholesteric liquid crystals (CAdCLCs) is reported. Pitch length of CAdCLCs illuminated by green and purple lights can be decreased and increased, respectively. The expansion of bandwidth of reflection light of CAdCLCs by simultaneously illuminating green and purple lights on the same side and on the opposite sides of CAdCLC cell is investigated. The optimized method to expand bandwidth of CAdCLCs is also discussed.

 

Since the spectral responses of commonly used camera sensors do not have a linear relationship with the CIE color matching functions, it shows serious metamerism color mismatch in the measurement of different types of displays. Color errors caused by the instrument-to-observer metamerism are effectively reduced by a proposed 5-stage method which takes spectral radiance of the reference and the test displays into account.

  Preview abstract

This paper reports that a liquid crystal smart window based on double layer dichroic dye-doped nematic liquid crystals can be switched between transparent and dark states via the face recognition system consisting of programming language and circuit design.

 

A OLED using a new thermally activated delayed fluorescence (TADF) emitter achieved excellent performances in terms of current efficiency of 49.42 cd/A, power efficiency of 44.05 lm/W and external quantum efficiency of 18.14%. Moreover, the OLED presented blueish green emission wavelength of 496 nm, corresponding to color coordinates of (0.194, 0.429). Besides, the transient electroluminescence of the device exhibited an obviously delayed emission with decay time of approximately 2.39 μs, indicating delayed fluorescence character. Accordingly, employing the new TADF dopant in EML in OLED showed high efficiency, which was attributable to the effective utilization of triplet excitons.

 

-

  Preview abstract

By matching the emission spectrum of the exciplex co-host with the absorption spectrum of the near-infrared emitter, the Förster resonance energy transfer (FRET) process boosts the maximum external quantum efficiency of the near-infrared organic light-emitting diode to 5.3% with an electroluminescence wavelength of 774 nm.

 

We demonstrated a new nanostructure with QD color conversion layer to reduce the thickness of the device. In the second part of the research, the multiple light scattering of nanoporous (NP) GaN was fabricated and applied QD for Micro-light-emitting diode (Micro-LED) display applications. Colloidal QDs were printed into NP-GaN by using ink-jet printing technique, and 92.3% and 97.6% of light conversion efficiencies for green and red were achieved, respectively. Furthermore, NP-GaN structure embedded with QD could avoid self-aggregation effect after inkjet printing.

 

A mini-LED driving circuit using LTPS TFTs to provide uniform driving currents with low power consumption. Simulation results indicate that the relative current error rates are below 7.34% with VSS rise of 0.5 V as VTH varies ±0.3 V. Compared to 6T1C circuit, proposed circuit improve power consumption by 23.75%.

  Preview abstract

With the benefit from the properties of the adopted materials, such as polyhedral oligomeric silsesquioxanes (POSS), photoresist, and dichroic dyes (S428), in this study, vertical and hybrid alignments form periodic structures in a liquid crystal (LC) cell to get the same properties as privacy films.

 

Amphiphilic Au nanoparticles (NPs) decorated with PEGylated graphene oxides (AuNPs@PEG-GO) were synthesized to incorporate into thermally activated delayed fluorescence organic light-emitting diodes (TADF OLEDs) for improving the device performance. Because AuNPs@PEG-GO could be well dissolved in both deionized water and organic solvents, we blended the amphiphilic Au NPs into the poly(3,4-ethylenedioxythiophene): polystyrenesulfonate (PEDOT:PSS) layer and the organic photoactive layers of TADF OLEDs simultaneously to realized dual plasmonic structures. The the device performance had been significantly improved due to the effects of localized surface plasmon resonance. The current efficiency has been enhanced by up to 68%.

 

In this research, a novel green thermal activated delayed fluorescence emitter based on naphthyridine (ND) derivatives, was synthesized and employed as high efficiency organic light-emitting diode (OLED). By optimizing the dopant concentration of emitter in the emitting layer (EML), maximum external quantum efficiency (EQE) reached 14.9% with CIE coordinates of (0.36, 0.57).

 

Tetraphenylethene (TPE) has been demonstrated to be an effective core molecule for generating excellent aggregation-induced emission. This study proposed a new series of AIE compounds based on a triphenylethene moiety decorated with different carbazole-based substitutions. The carbazole and triphenylethene moieties shared a phenyl to sustain a TPE structure. As indicated, the non-doped blue-emitting organic light-emitting diodes (OLEDs) with GK235 emitter exhibited satisfactory peak efficiencies of 3.9%, 10.2 cd/A, and 10.6 lm/W. In addition, the maximum luminance was up to 39661 cd/m2, indicating our molecular and device designs possess a high potential for fabricating non-doped blue OLEDs.

 

The 80×160 passive-matrix μ-LED display was fabricated by using the laser direct writing and ALD techniques. The leakage current from sidewall defects were suppressed by an Al2O3 passivation layer from ALD system because of the non-plasma process and high surface coverage features. The illuminance of 866 cd/m2 was obtained.

 

In this work, a simple method for preparing thin films of a family of metal-organic framework, zeolitic imidazolate framework-8 (ZIF-8), which behave as hole injection layers in organic light-emitting diodes (OLEDs) is proposed. The ZIF-8 thin films are prepared through spin-coating of zinc nitrate hexahydrate (Zn(NO3)2·6H2O) and 2-methylimidazole (2-mIm) sequentially from their dimethylformamide (DMF) solutions. The brightness and current efficiency of the OLEDs using the ZIF-8 thin films achieve 600 cd/m2 and 3.8 cd/A, respectively. Our result indicates that ZIF-8 could be a simple solution-processable hole-injection layer for OLEDs.

 

CdSe/ZnS@SiO2 quantum dots (QDs) are mixed into SU-8 photoresist to realize 50 µm × 50 µm QDs color-converted μ-LED display. The distributed Bragg reflector is applied on the red/green QDs pixels to reflect 98.44% of the blue light and almost no restrictions on red/green light, suitable for full-color displays applications.

 

The main topic reported in this study is waveguide liquid crystal (LC) devices with asymmetrical light scattering properties and their applications. The key points we discuss herein include the asymmetrical light scattering optical characteristics when an edge light source is coupled into the proposed LC devices applied with suitable electric fields, and then scattered out of the LC devices.

 

We have developed a new fluorescent compound for a deep-blue organic light emitting diode
(OLED). The emission of the fluorescent emitter in solid film was 397 nm. We applied this fluorescent
material to fabricate a non-doped OLED. As a consequence, external quantum efficiency (EQE) of this
non-doped OLED was superior as high as 4.92% and also showed a deep blue emission with peaks of
382 nm and 398 nm, respectively. The emission wavelength of device is less 400 nm and which belongs
ultra violet (UV) region, corresponding to Commission Internationale de l'Eclairage (CIE) y coordinate
by 0.0423.


 

Efficient flexible light-emitting electrochemical cells (LECs) are fabricated on novel silicon-gallium-doped zinc oxide (SGZO) coated muscovite mica substrates. The proposed flexible LECs show excellent mechanical resistance, which can maintain more than 80% of the device performance after 10000 bending cycles with a radius of curvature of 10 mm.

 

We propose a new flexible transparent electrode that combines an ultra-thin metal alloy film with MGZO. The results showed that this highly transparent electrode showed low sheet resistance values before and after bending, demonstrating that the AgCr/MGZO composite film possesses great potential for the transparent electrode in flexible optoelectronics applications.

 

A single layer of amorphous InZnO is chosen as the channel material for a thin film transistor (TFT)-based driver and sensing layer for a blue-light sensor, respectively, with a completely compatible process integrated into in-cell embedded photo sensor architecture. The photo sensor exhibits a high optical responsivity (1720 A/W) and good signal to noise ratio (~103) under the low blue light illumination. Afterwards, the detail studies and important issues about the sensing and material characteristics of a-IZO thin film in the TFT sensor are discussed.

  Preview abstract

A bipolar emitter was synthesized for non-doped white organic light-emitting diode application which exhibited Commission Internationale d'Eclairage (CIE) coordinates of (0.31, 0.29).

 

In this work, we show the high protection structure of low-diffraction flexible transparent Micro LED display, featuring high transmittance, high background clarity and high protection effect. There were lots of technological innovations such as a unique pixel design, fabrication on PI substrate, and high strength-stress characteristics. Finally, we demonstrate the display with the high-protection film layer, the results showed the transmittance would not be reduced, the anti-diffraction effect remains the same, and it also has the good characteristics of scratch resistance, abrasion resistance and impact resistance.

  Preview abstract

Novel bipolar host material with 4CzIPN as the dopant by three different concentrations, 6%, 10%, and 13% were demonstrated. The optimums device shows the external quantum efficiency of 21.4%, the low turn-on voltages of 2.4V at 1 cd/m2, the luminance of 4185 cd/m2 at 6V ,EL spectral peak of 516 nm, and CIE coordinates of (0.277, 0.582) and low efficiency roll-off under high luminance.

 

-

  Preview abstract

In this work, we developed a complete exciton diffusion model to help researchers to understand and analyze exciton behavior in organic light-emitting diodes (OLEDs), especially triplet-triplet fusion and thermally activated delayed fluorescence OLEDs. This exciton diffusion model considers both singlet and triplet exciton to simulate OLEDs performance successfully, which includes singlet-singlet quenching, triplet-triplet quenching, triplet-singlet annihilation, triplet-triplet annihilation.

 

We have considered the problem that the backlight image will cause serious LED brightness's unevenness in the insufficient light mixing distance. Experimental results have shown that the proposed method can successively detect and locate defects in a direct-light backlight, achieve the purpose of high-speed development process and efficient products management.

  Preview abstract

We presented a numerical result for computation lithography patterns using Hopkins’s equation. We investigated the lithography patterns under different sources wavelength and numerical apertures. We observed that the line width of the pattern increases as the numerical aperture NA changes from 1.56 to 1.2 due to the diffraction effect.

  Preview abstract

In this work, the minimum required viewing distance of a large-size LEDs with pixel pitch of 4 mm was reduced by covering optical diffusers. The light passed through the diffuser from LED was re-distributed evenly to hide the LED hot spot and increase the effective emitting area. The minimum required viewing distance decreased from 11.4 m to < 5 m with the high effective emission area, but also caused some side effects which may downgraded image quality. We used MTF calculated by the LSF to compare the evaluate image quality.

  Preview abstract

In this paper, a new a-Si TFT gate driver with providing the triggering signals to Vth compensation pixel circuit for the AMOLED application with external compensating block has been proposed. The proposed gate driver could provide the different pulse width signal using the additional triggering circuit block in the blanking time for the AMOLED. The simulating result shows not only reaches the goal for outputting another pulse for the blanking time but also achieves the measurement test with real panel loading.

 

In this study, a double emitting layer (EML) structure with a red Ir(piq)2acac and a deep-red Ir(fliq)2acac was designed to generate a broad EL spectrum. The host material of the EML used TCTA:CN-T2T exciplex system, aiming to boost the carrier density. The optimized OLEDs with a broad spectral profile possess a 90% coverage ratio in the target ranges from 630 to 690 nm, together with a high peak efficiency of 17.5%. The power density of the device recorded at 5 mW/cm2 was 5.9 V. These results illustrate the feasibility of our design concepts.

 

Optimizing the electroluminescence performance of organic light-emitting diode devices is critical for display and lighting applications. In this work, we modified the hole injection interface by inserting an electron donor interlayer and boosted the external quantum efficiency of the exciplex-based OLED to 18.08%.

 

Long-term browsing of smartphones can plausibly cause permanent damage to retina. To prevent, one can use the eye protection modes equipped therein. We had investigated the effectiveness of three features, i.e., default setting, blue light filter mode and dark mode, offered by three iPhones (i.e., iXR, i11 and i12 Pro) on reading safety and clarity. The results showed that both blue light filter and dark modes could significantly increase the permissible reading time. Nevertheless, the two modes had simultaneously compromised slightly the browsing clarity.

  Preview abstract

We prepare that by incorporating polyethylene oxide (PEO) into the CsPbBr3-perovskite to improve the morphology of an all-inorganic-perovskite emissive layer. Consequently, the optimized CsPbBr3-PEO LED exhibits a maximum luminance of 3664 cd/m2 and external quantum efficiency of 0.06%.

  Preview abstract

The research proposes a qualitative model derived from psychophysical experiments and the measurement of images on virtual reality devices. The machine learning algorithm establishes an evaluation method for the human eye-perceived stray light. Four approaches are compared and the model's accuracy is as high as about 90% by all algorithms.

  Preview abstract

A deep-blue fluorescence organic light emitting diode (OLED) was demonstrated by incorporating a novel emitter based on acridine moiety. The devices showed its max current efficiency (CEmax) of 0.56 cd/A, maximum power efficiency (PEmax) of 0.50 lm/W, maximum external quantum efficiency (EQEmax) of 0.97%, Commission Internationale de l'Eclairage (CIE) coordinates of (0.153, 0.061) and peak emission wavelength at 438 nm when the dopant concentration was 1%.

 

Adding Cl ions into CsPbBr3 to achieve sky-blue wavelength, these combinations will cause the emission wavelength to blue shift. Adding different proportions of PEABr, the 3D perovskites can be converted into a quasi-2D perovskites, the sky-blue perovskite LED show maximum luminance and EQE of 436 cd/m2 and 2.28%.

  Preview abstract

High-quality perovskite CsPbBr3 quantum dots (QDs-CsPbBr3) doped with Dimethyldidodecylammonium bromide (DDAB) material were prepared using hot-injection method. The photoluminescence of DDAB:QDs-CsPbBr3 was characterized by excitation wavelength of 523.1 nm, with narrow line-width emission of 20.47 nm. The QDLEDs exhibits a maximum luminance of 4637 cd/m2

 

A psychophysical experiment is carried out to understand the white appearance of a tablet display under 3500K and 6500 K with easy illuminance level of 150 lx and 300 lx. The results show that the observers rate a higher whiteness percentage for the whitest stimulus under the lower illuminance level.

  Preview abstract

In this research, we explore the effectiveness of different anti-blue light screen protectors. We found that the effectiveness of commercially available screen protectors are relatively limited; the highest effectiveness is only 15% and the lowest is 8%. If using color conversion films, the highest is 19 times better and the lowest is 1.6 times. The color conversion films exhibit yellowish or orangish color, which might compromise color fidelity. Hence, optimization should be made between the effectiveness and color fidelity.

  Preview abstract

Micro-LED displays have been regarded as the next generation of displays. However, the far-field radiation pattern of the micro-LED would be very different from the LED with large scale. In this study, the far-field radiation patterns of LED with different chip size are investigated by numerical calculation. The ratio of the light emitting from the top surface to the light emitting from side surface with different chip size are also conducted.

  Preview abstract

In this study, we have developed cholesteric liquid crystals with different pitches. The cholesteric liquid crystals are formed into a ULH (Uniform Lying Helix) structure through the cooling phase transition and the application of uneven horizontal fields, respectively. The electro-optical properties of the ULH structure are discussed.

 

In this study, a ULH structure of cholesteric liquid crystal is combined with a three-layer electrode structure. The cholesteric liquid crystal is applied with an inhomogeneous horizontal electric field to form a ULH structure, and then four types of vertical electric field are used to generate optical switching of the ULH structure with sub-millisecond response.

 

In this work, a twisted nematic liquid crystal (TNLC) cell with appropriate pitch length and cell gap, which is capable of electrically switching between the twisted and homeotropic states, was fabricated. Furthermore, the characteristics of optical properties of such a TNLC cell was investigated by comparing the simulated and experimental transmittance spectra.

 

Host materials must have higher triplet energy than the emitter to ensure exothermic energy transfer. To attain balanced charge transport for phosphorescent OLEDs, we proposed new host materials with carbazole/triphenylamine as hole transporting moiety and cyano along with benzimidazole as electron transporting core. Both bipolar compounds, TPA-ImdCN and 4-Cbz-ImdCN, possess good thermal, photophysical, and electrochemical properties, which are suitable to combine with Ir(ppy)3. The device with 4-Cbz-ImdCN host exhibited higher peak efficiencies of 11.4%, 39.3 cd/A, and 46.8 lm/W. These results clearly implied that these molecular designs possess a high potential for developing bipolar hosts.