Research On Design And Fabrication Of Light Guide Plate

With the development of science and technology, the liquid-crystal display has been the mainstream finally substituting for the Cathode Ray Tube. Because liquid-crystal display cannot certainly shine by itself, it needs the backlight module to realize its display function. In backlight module, light guide plate (LGP) is a key-component because of the function of guiding light. With the thickness of LGP decreasing and the quality request to make light achieve high brightness and the uniformity, the design and fabrication of LGP is very important. The paper is focused on the design and fabrication of LGP. A method of fabricating light guided plates (LGP) is presented, based on DMD micro-lithography and micro-imprint technique. And the experimental measurement results are also given in this thesis.Firstly, the current stage and development trend of liquid-crystal display are summarized. The development of backlight module technique is also introduced. In the end, the traditional methods of fabricating LGP are introduced in detail.In the second chapter, the optical principle of LGP is given. Some knowledge about luminosity in the test of LGP has been described.A model is set up to derive the rule of scattering netted dot arrangement by the optical theory. Light out function is calculated under ideal condition and some factors about affecting uniformity of LGP are analyzed.In chapter three, the function of Trace-pro software is explained. A process optimization of LGP by Trace-pro is described in detail for different micro-structure designing. Some illumination maps about different LGP are got by ray-tracing. A kind of LGP design has been obtained by Trace-pro software, whose uniformity can be achieved up to 86.2%.In the forth chapter, a flexible and efficient solution for fabricating ultra-thin light guided plates (LGP's) has been presented. The approach is based on mask-less lithography by use of digital micro-mirror device (DMD) in the laser lithographic system. The patterns with microstructures created by DMD is further reduced to be projected on the photo-resist plates, and exposed. With the developing and silvering and electroforming procedures, a nickel template with microstructures has been obtained. The nickel template has been used to fabricate LGP by hot embossing technology. The mentioned method above has the advantages of arbitrary microstructures created by mask-less lithography and cost-effective mass production by embossing replication.In the fifth chapter, the guide light effects of different LGP are measured by BM-7A instrument. The uniformity of LGP in the experiments can be achieved up to 76.2%. The results show that the microstructures of netted dot play an important role on the guide effect of LGP.Finally, the subject of this study are summarized, and pointed out what can be done in the future work.