Technical Name Low glare white LED
Project Operator National Taiwan University of Science and Technology
Project Host
The invention combines a white light emitting diode with a metal wire-grid polarizer to form a packaging structure of a polarized white light emitting diode. The packaging structure can improve the excess color temperature, the non-uniform intensity distribution and luminous efficiency. At the same time, multiple reflections or scattering can be reduced to eliminate glare effect for the direct or indirect viewing of light source.
Scientific Breakthrough
This innovative technology proposes a polarized white light-emitting diode package structure, combining the white light emitting diode with the metal wire-grid polarizer. A reflective packaging substrate, a yellow phosphor layer and a wire-grid polarizer are combined to form an pumping cavity. The pumping cavity is used to recycle the undesired polarized blue light beam reflected by the reflective polarizer, and to multiple pumping the yellow phosphor resin layer. Therefore, the luminous efficiency and extinction ratio of polarized white LED can be enhanced. At the same time, the nano-structured surface of the wire-grid polarizer is placed downward to the yellow fluorescent layer to protect the delicate polarizing layer from damage and enhance the durability to the environment. Polarized white light emitting diode can improve drawback of the traditional white LED such as glare, excess color temperature and luminous non-uniformity. At the same time, the polarized white light LEDs can reduce reflection and diffusive scattering, and diminish the effects of glare for direct or indirect viewing of light source. This patent combines the white LED packaging structure with the commercial available polymeric reflective polarizer, Hence, with the traditional white LED production process, mass production and low costs of polarized white LED can be achieved. The polarized white LED light source has the advantages of low glare, color stability, luminous uniformity, high extinction ratio, high transmittance (>70%), low color temperature, low scattering, simple packaging process, and lower production cost. Ideal white light source for lighting focus on brightness, tunable color and comfort. However, comfort demands a glareless light source such as polarized LED lamp through reducing the surface reflection and diffusive scattering. The advantages of polarized LED head light is to increase eye comfort for driver and enhanced mutual driving recognition on night driving. Polarized lighting for the image forming can enhance the image uniformity, contrast and resolution.
Industrial Applicability
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