Study On New White Light Source Base On LARP Technology

In recent years, researches on the lighting device, which uses fluorescent light as illumination light, have been prevailing in the field. This illumination light is produced from phosphor-containing light-emitting part activated by light emitting diode and semiconductor laser diode working as excitation light source. The white-light lighting source, which is based on Ga N Blue LED, has sparked a science and technology revolution to save energy and improve efficiency. However, due to LED light source has serious light attenuation and unstable light color, restricting its development in the field of high power and special lighting applications, while on the contrary, the technology of laser activated remote phosphor（LARP） has a series of advantages, such as high brightness, low beam divergence, long life span and stable performance, all of which make semiconductor laser especially suitable for the special lighting fields including laser headlights or projection display, etc.In this paper, I study the technology of laser activated remote phosphor（LARP） and their applications on new white-light lighting source, the research include the technology of laser activated remote phosphor（LARP）, to establish the experiment device of laser white-light source, and design of high power semiconductor laser light source module for fluorescence excitation and the research of optical fiber coupling technology and so on. The main work is as follows:1. In order to optimize the efficiency of laser activated remote phosphor（LARP）, in this paper, I did a large number of experiments and researches on the influences of phosphor’s concentration, thickness, powder-rubber ratio, and laser’s power density, duty ratio and modulation frequency to the efficiency of the phosphor excitation, and found that laser phosphor excitation efficiency reaches the top when phosphor ’s concentration is 0.4mol/L, phosphor’s thickness is 1.05 mm and phosphor’s powder-rubber ratio is 1:5. Meanwhile, I verified a way to improve the flux of fluorescent light through experiments. For example, the flux of fluorescent light activated by 30% G1758 phosphor mixing with 70% GAL535 phosphor is 7.3% higher than that by single phosphor EG2762.2. According to the design principle of laser white-light lighting device, I structured laser white-light source physical machine platform, used blue LD of single pipe to activated yellow YAG phosphors in a remote way, and achieved the highest luminous flux of 31.490 lm. When the current is 0.8 A, light conversion efficiency is 36.7 lm/W, By adding a small amount of red phosphor into YAG phosphor, the color rendering index of laser white-light lighting source increased from 63.0 to 71.0. On the target surface at 4.0 m distance away from the optical system, laser white-light’s illumination uniformity reaches 83.6%, and the divergence angle of the laser white-light lighting source beam comes to 5.220.3. In order to obtain high power laser light source module for fluorescence excitation, I chose Mitsubishi red LD as test samples and used Zemax software did semiconductor laser beam shaping design for the encapsulated red LD array, as well as designs for the inversion binoculars flare compression system and the optical fiber coupling lens. As a result, I obtained the smallest RMS radius under ideal optical system – 1.959 um. However, during the experiments and researches, due to serious optical system adjustment error and insufficient laboratory equipment precision, the optical coupling efficiencies of 2 ′ 3 red LD arrays are quite low, among which, the single red LD₁2 through the optical system coupling efficiency is 47.8%.