A systematic standard for developing light extraction technologies that can improve the efficiency of lighting systems based on the optical design method of flat-type lighting devices needs to be established. The design of a flat-type lighting device was investigated, considering the utilization of precise processing techniques that simplify the manufacturing process. These techniques adjust the processing variables of the geometric pattern of the light guide plate (LGP), light-emitting diodes (LEDs), which are placed on the sides of the LGP, and viewing angle. The amount of light lost was reduced by etching the light-incident surface of the LGP as a curved shape. A pattern spacing of 9 mm was used to control four LEDs placed in the middle of each side of the LGP with a viewing angle of 120 deg and four LEDs placed at the corners with a viewing angle of 60 deg. In addition, hotspot generation was prevented by controlling the amount of light concentrated in the light-incident area, and the illuminance uniformity of the LGP was confirmed to be 95%, showing an improved optical efficiency. By controlling only the pattern spacing, position of the light source, and viewing angle of the LEDs, the optimal design conditions to improve the optical efficiency of the flat-type lighting device were established. It was found that these parameters can sufficiently improve the imbalance caused by the concentration and loss of light.
Future advances in mass production technologies and the implementation of market creation ideas based on technological convergence can be expected in the lighting sector of the information display market, allowing the development of high-value-added products. The challenges faced, with regard to conventional lighting systems, in achieving an increased manufacturing efficiency via simple processing techniques by utilizing minimal light sources are identified. Consequently, a performance evaluation was conducted for an improvement in the optical characteristics. This was achieved by optimizing the shapes of geometric scattering patterns and the positions of the light sources near the light guide plate (LGP). Based on the results, an effective structure of an LGP for large-area, flat-type lighting systems is proposed. To evenly distribute the incident light, a light-emitting diode (at a beam angle of 60 deg) is placed at each corner of the LGP. Moreover, it was confirmed that the optimum condition for improving the optical characteristics of the applied light is a curved pattern starting from each corner. To increase the illuminance efficiency, this curved pattern is inclined toward the center. Further, the illuminance is approximately doubled (592 lux) when the pattern spacing is reduced, creating an optimal design approach for improving the optical characteristics of a large-area, flat-type lighting system.
In this paper, we had designed the hole transport layer of the new composite skeleton structure having a high energy band gap, high triplet energy and charge mobility. And we proposed a new structure to incorporate carbazole on thiophene to solve energy band gap, triplet energy and charge mobility. The structures and properties of the synthesized compounds were characterized by NMR, fluorescence spectroscopy, triplet energy, charge mobility. As a result of NMR measurement, it was confirmed that when analyzing the integrated type with the position where the measured peak is displayed, it agrees with the structure of hole transport materials. The emission characteristics of the hole transport layer material showed absorption characteristics at 401nm and 377nm, respectively, and exhibited emission characteristics in the range of 460nm and 435nm. respectively, The triplet energy was 2.78 eV and mobility was 7.12X10-6 cm2/Vs.
We propose curved V-groove-based patterns for light guide plates (LGPs) and demonstrate their performance by calculating their uniformity and luminance. Instead of the linear V-groove patterns used in previous research, curved patterns with asymmetric V-groove cuts were applied to the LGPs. The feasibility of obtaining enhanced uniformity and luminance from LGPs with the proposed patterns was evaluated by varying the degree of asymmetry of the V-grooves themselves and the distance between the V-groove patterns. The suggested patterns provided more stable uniformity with a small number of patterns and a large distance between patterns. The number of V-grooves is directly related to the processing time, and the degree of asymmetry in the V-groove cuts corresponds to the processing error during fabrication. Therefore, the proposed patterns could be fabricated with a low tolerance and shorter processing time. Their use would contribute to the cost-effective fabrication of LGPs. Because LGPs using the proposed patterns exhibited uniform illumination, a small number of curved patterns composed of asymmetric V-grooves can improve the characteristics of edge-type backlighting.
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