Investigation On The Receiving Lens In The Visible Light Communication System

Visible light communication(VLC, visible light communication) technology is developed in a white LED light technology for emerging wireless communication technology. It uses high-speed flashing signal light emitted from the LED which is difficult to distinguish by naked-eye to convey information. It can achieve functional lighting and communication. Compared to conventional radio communications and other wireless communications, VLC radio spectrum without authorization, has some advantages, such as good security, high transmission power, transmission speed, and no electromagnetic radiation and interference and so on. Key technologies in Visible light communication include coded modulation, selection and placement of the light sources,overcome ISI, reception demodulation technology and full-duplex mode. The research and development direction of the optical lens in visible light communication system receiver end is small size, light weight, short focal length, high condensing efficiency, large viewing angle, etc., so the lens design and optimization is essential. In this paper, we design and optimize the receiving lens in visible light communication system, the main contents include:Fresnel lens is designed for visible light communication system as the receiving lens, changing lens parameters, ray tracing its clustering effect, to study the angle of view, design and optimize the structure and parameters of lens. Through the modeling and simulation,Analysis the influence of the aperture, F number, the number of rings on the Fresnel lens concentrating effect and angle of view, finally in the use of a single lens,Choose the diameter of 40 mm, F number is 1, the ring number of 40 mm Fresnel lens as a visible light communication system receiving lens.Use the plano-convex lens and Fresnel lens as primitive to design compound eye with plano-convex lens, fresnel with plano-convex lens and compound eye with Fresnel lens, design and optimize the structure and parameters of the lens through theoretical modeling. Fresnel lens of compound eye compared to the compound eye of plane convex lens reduces the lens material, and the surface more smooth, but its production process more complicated.The plane of the compound eye lens can be used as a receiving lens in multi-input multi-output(MIMO) technology of visible light communication system, curved compound eye lens can greatly expand the receiver lens field angle, reduce the source array layout requirements, we can choose the appropriate lens for receiving lens of visible light communication system.Use negative refractive properties of quasicrystals, proposes to use quasicrystals flat lens as the receiving lens of visible light communication system, and produce quasicrystalline photonic crystal structure from the experiment.