The Projectors Designed For The Surface Illuminance Uniformity Of The LED Flat Light Without The Light Guide Plate

With the unique and natural lighting effects, the white LED flat light hasbeen widely praised. In view of the low light coupling efficiency between thelight guide plate and the LED, the big loss of the absorption and thereflection, this paper studies a LED flat light without the light guide plate,aims at optical design of the projectors to receive surface illumination evenand improves the light efficiency and illumination uniformity. The projectorinstead of the light guide plate can make the LED flat light weight light,lower the costs of production and the light loss is less. In general, thetraditional projectors are on the purpose of the positive uniform illumination,and the main innovation point of this topic lies in the side that it is the firsttime to study the LED projector for the near field uniform illumination,except that, it realized the high light efficiency and the uniformity of thesurface brightness is great. It expands the application field of LED projector.While the research status of the LED projector are discussed in the paper,it also introduces how to take use of MATLAB, SolidWorks and TracePro todesign the projector and set up the model of the LED flat light without theguide plate LED.Based on the special structure of the LED flat light without the light guideplate, the two kinds of the efficient LED projectors are researched. Oneprojector is the freeform surface lens which is used for the single LED flatlight. The other is the cylindrical array projector which is used for thedouble-sided LED flat light. The LED projectors redistribute the LED lightsource. Based on geometrical optics and the principle of conservation ofenergy, the projectors make the emergence light of the LED for asegmentation according to the degree of poloidal angle of the light, dividingthe light energy (flux) evenly and ensure the same segmentation region havethe same number of light. Those projectors take advantage of programming in MATLAB to receive the curve of total reflection and refraction of theprojectors. The optical models are set up by SolidWorks software, thenimporting them into the optical simulation software TracePro to validate theoptical effect of the design model and its feasibility of application in the LEDflat light. Results show that the designed cylindrical lens array LED projectorsused in the LED flat light without the light guide plate applied to the LEDflat light size240mm×360mm whose light utilization best can be up to96.03%, and the illumination uniformity of the target surface with thefreeform surface lens best (the out smooth of the LED flat lamp) can be up to96.6%.According to the above designed projectors, the laser marking machine isused to manufacture the mould of the LED projectors. It includes the mold ofthe cylindrical lens array LED projector and the freeform surface LEDprojector lens, then produced the PMMA projectors by the compressionmolding machine. Compare the theoretical simulation to the experimentalresults, verifying the validity of the design method. The experiment provesthat the illumination uniformity of the flat lamp panel is95.74%,...