| Summary: | 博士 === 國立成功大學 === 系統及船舶機電工程學系碩博士班 === 101 === In recent decades, environmental protection has become one of the hottest topics. Considering the current context of low-carbon economy (LCE), it has become an inevitable trend to replace traditional and energy-wasting lamps with highly energy-efficient LED lights, especially in the field of underwater illumination. However, in the field of marine research, LED applications are only confined to replacement of traditional light sources directly without any specific design. In view of that, this study presented a series of design processes directed towards LED. The underwater lighting system based on LED light sources was developed and applied to underwater visual technology.
Underwater visual technology is the most direct method for underwater exploration that can display underwater conditions most clearly. However, its quality of image observation is greatly affected by underwater illuminance. Besides, a traveling light is absorbed and scattered by water. Although the power of a light source can be increased to lengthen the range of underwater imaging, the image will become much fuzzier due to the effect of scattering. Therefore, this study first calculated a non-uniform luminous intensity distribution curve (LIDC) through the scattering model of an underwater light field. Thereafter, the method for LIDC Mapping was employed to design lenses with a special energy distribution. Such lenses reduced the scattering effects of an underwater environment on light, thus improving image quality. Through the above method, the design of lenses was simplified as a correspondence between angles and was quickly completed with the aid of Snell's law, or the law of refraction. In addition, this study presented a hybrid flat plate heat pipe (FPHP) designed exclusively for a heat source with high heat flux. Having a coronary-stent-like support combined with a copper mesh plus groove structure, the novel heat pipe greatly improved its horizontal thermal conductivity, solving the problem with hot spots of LED.
Pursuant to the lighting requirements of underwater photography, this study completed a lens with a non-uniform luminous distribution. Moreover, according to the results of lighting analysis, a hybrid structure heat pipe was developed, and then an LED lighting system for underwater photography was completed. As indicated by the test results, the experimental value of the lens designed in this study reached 96.15% of the theoretical value after normalized cross correlation (NCC) was evaluated. In addition, the hybrid heat pipe maintained a thermal resistance of 0.143 ℃/W under an input heat of 40W. Finally, through an experimental tank, this study simulated underwater photography around a sea estuary. Compared with the pictures taken in pure water, those obtained through the lighting system reached a peak signal-to-noise ratio (PSNR) value of 13.3 dB. In comparison with the ordinary lighting fixture with a uniform light field underwater, the new lighting system raised the PSNR value by about 1.1 dB.
|
|---|
