Design And Color Aberration Correction Of Head Mounted Displays

Head Mounted Display(HMD)is an off-axis system that combines refraction and reflection surfaces.However,from the user's point of view,compactness,lightness and ease of use are the key factors to measure the practicality of a device.Therefore,how to build a suitable design starting point to reduce weight and improve imaging quality is also an important research directionIn this paper,the performance and limitations of different structured HMDs and the ability of Diffractive Optical Elements(DOE)to correct chromatic aberrations are investigated.By setting the system structure constraints,a Total Internal Reflection(TIR)prism and a folding prism system with and without Optical See-Through parts are built,the structures of these systems are compared and analyzed.Using the optimization method described in this paper,combined with the use of free-form surfaces,the Lagrange invariant L is set to a constant scale factor,making the results more comparable.Ensuring that the system meets the Modulation Transfer Function(MTF)and distortion requirements,the Field of View(Fo V)and Numerical Aperture(NA)are fine-tuned to obtain the limiting values of aperture size and field angle for different systems.Ultimately,a global view is given to the designer,making it possible to quickly find the best design starting point according to the design requirements when designing such optical systems.The correction of chromatic aberrations is achieved by introducing Diffractive Optical Elements,which are placed in different positions of the optical system,in combination with the optimization method given in this paper.By extracting the basic parameters of the optical system and obtaining the color aberration values of different field points before and after the optimization,with the help of the color aberration formula,and the results are compared with the color aberration before optimization to obtain the best position of the diffractive optical element when correcting the color aberration.Finally,the feasibility of the diffractive optical element for correcting the color aberration is also demonstrated.