The phase-sensitive optical time-domain reflectometry (Φ-OTDR) has been developed rapidly as a fully fiber-optic distributed vibration sensing technology. However, the demodulation technique based on the phase term would induce a serious false alarm problem due to the signal fading effect. An effective method to suppress fading-induced false alarms in the Φ-OTDR system is proposed, which is based on the suppression mask and numerical relationship between phase and amplitudes of Rayleigh backscattering. The performance of the proposed method has been experimentally demonstrated in both laboratory environment and in-field situation test. Without any hardware addition in a traditional Φ-OTDR equipment, false alarms rate can be reduced from 4.81% to 0.15%, whereas low missing alarms rate can be achieved at the same time. In-field results show that this work provides a low-cost solution to enhance the performance for real-life engineering application of the phase-discrimination Φ-OTDR system.
A higher color gamut can bring more comfort to one’s watching experience; therefore, it is a key aspect when assessing the quality of the display. To improve the color gamut of a display, many techniques have been used. Although some techniques have been claimed to work, the overall quality of the color gamut of the display still does not satisfy many researchers. In this paper, we will consider several key factors that can affect the color gamut of the newly developed laser display system, including the center wavelength of the Quantum dot film, the efficiency of the Brightness Enhancement Film, and the quality of the color filter of the liquid crystal display panel. An improvement of nearly 45% can be achieved through fine tuning of the key factors when compared with our earlier models without finetuned ones. The average color gamut of the laser quantum dot backlight display system can reach up to 110% NTSC color gamut that yields vivid color results.
Luminance is a key factor for outside displays because of background light interference. Many methods have been used to enhance the luminance of backlit display systems. The key to enhancing the luminance of a backlit system is to increase the light coupling between the light guided plate (LGP) and the light source. In this paper, we present an effective method to enhance light trapping and boost light harvesting by introducing cross-grooved textures on the side surface of the LGP. Elevated light coupling between the line laser and the LGP with a cross-grooved texture has been observed in both 3 mm and 4 mm thick LGPs, respectively. A light trapping mechanism has been proposed in which greater interaction surface area between the LGP and line laser source and an elongated light traveling channel contribute to overall light trapping. As a result, reduced reflection loss boosts light harvesting. A nearly 100% luminance efficiency enhancement has been achieved using this simple technique.
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