We report a corrugated structure to effectively extract the surface plasmon polaritons (SPP) and waveguiding modes in organic light-emitting diodes (OLEDs). This structure is formed by nano-imprint of blazed gratings. To study the optimum extraction condition in terms of grating pitches, we compare the light extraction efficiency of corrugated OLEDs with three kinds of pitches, showing a 42.00% external quantum efficiency (EQE) enhancement ratio with this internal structure. Due to the transfer of SPP and waveguiding modes into substrate mode, the EQE enhancement ratio can be further pushed to 103.02% by attaching a macrolens. The simulation verifies the experimental results and shows the extraction mechanism of the corrugated structure towards transverse electric (TE) and transverse magnetic (TM) waves. We foresee that this method is able to enhance the optical efficiency of devices for both mass-production OLED lighting and display in a cost-effective way.
A quantitative description of an optical moiré pattern produced in an autostereoscopic liquid crystal display system is proposed using a contrast sensitivity function. The numerical simulation, carried out in the spatial frequency domain, is applied to a directional backlit, spatially and temporally hybrid controlled display system. The moiré pattern produced from the superimposed binary optical components is examined systematically, and the results show that the visibility of the moiré pattern can be manipulated with proper grating settings. Good agreement between experiment and simulation demonstrates that the proposed theory can be applied as a design guideline to remove the moiré patterns occurring in an autostereoscopic display system.
Light scattering is a common physical phenomenon in nature. The scattering medium will randomly change the direction of incident light propagation, making it difficult for traditional optical imaging methods to detect objects behind the scattering body. Wiener filtering deconvolution technology based on the optical memory effect has broad application prospects by virtue of its advantages, such as fast calculation speed and low cost. However, this method requires manual parameter adjustment, which is inefficient and cannot deal with the impact of real-scene noise. This paper proposes an improved Wiener filtering deconvolution method that improves the exposure dose during the speckle collection, can quickly obtain the optimal parameter during the calculation phase, and can be completed within 41.5 ms (for a 2448 × 2048 image). In addition, a neural network denoising model was proposed to address the noise issue in the deconvolution recovery results, resulting in an average improvement of 27.3% and 186.7% in PSNR and SSIM of the images, respectively. The work of this paper will play a role in achieving real-time high-quality imaging of scattering media and be helpful in studying the physical mechanisms of scattering imaging.
Autostereoscopy is usually perceived at finite viewpoints that result from the separated pixel array of a display system. With directionally illuminated autostereoscopy, the separation of the illumination channel from the image channel provides extra flexibility in optimizing the performance of autostereoscopy. This work demonstrates that by taking advantage of illumination freedom, seamless viewpoints in the sweet viewing region, where the ghosting does not cause significant discomfort, are realized. This realization is based on illuminating the screen with a polyline array of light emitting diodes (LEDs), and continuous viewpoints are generated through independent variation in the radiance of each individual LED column. This new method is implemented in the directionally illuminated display for both single and multiple viewers, proving its effectiveness as a valuable technique for achieving a high-quality and high-resolution autostereoscopic display with seamless viewpoints.
25 May 2016 in SID Symposium Digest of Technical Papers