Optical Dsign And Rsearch Of Low Cost Miniature Projection System Based On LED

The user not only pays attention to the image quality of the projector,but also expects the projector to be more compact and lightweight.Therefore,micro-projectors will become an important research direction.The traditional projection system has a large volume,a complex structure,a high cost,and a low utilization efficiency of the light source.In the traditional projection technology,the monolithic DLP projector has a smaller volume and a better imaging quality,which can take both the system volume and the imaging quality into account.However,components such as color wheel,relay lens,and mirror are needed in the optical path system.In the process of working,the color wheel will not only reduce the utilization of light,but also cause some impact on the heat dissipation of the projector.The aging of the color wheel also limits the service life of the projector.On the other hand,the traditional projection light path,Following the lens,mirrors,the use of light,the entire machine's volume,weight,cost have a certain negative impact.Therefore,in view of the defects of the prior art,it is necessary to improve and optimize the light path of the conventional projector;it is necessary to reduce the components,simplify the structure of the projector optical system,reduce the volume,and reduce the cost.This article introduced the development history of projectors,and the research status at home and abroad,and put forward three kinds of designschemes.All three design schemes use digital micromirror devices as the core device.First,the projectors are calculated using the principles of geometric optics and non-imaging optics.The parameters of each component,then use the optical software TracePro,ZEMAX modeling,optimization and ray tracing,and finally analyze the simulation results.All three options do not require a color wheel or reflector.In the first scheme,a single tri-color LED light source is used,and a single lens forms a projection light path structure with parallel light incident on the DMD surface.The second scheme uses a tricolor LED array as an illumination source and a gradient index lens array to form a parallel light projection system.The simulation results show that both of these two designs can improve the light utilization efficiency,improve the uniformity of light spot,and further reduce the volume.In order to improve the imaging quality of the projector,the third scheme uses the laser as the illumination light source,expands the beam and collimates the laser beam,modulates the phase using the bit-picture,and realizes the combination of the RGB light sources with the X prism.In order to solve the problem of laser speckle,piezoelectric ceramics are combined with bit images to divide the temporally continuous laser into multiple independent laser pulses to generate N independent speckle images,superimposing N independent laser speckle patterns.In order to achieve the inhibition of laser speckle.