Two-dimensional pupil expansion method based on liquid crystal polarizer grating

Abstract

The invention discloses a two-dimensional pupil expansion method based on a liquid crystal polarizer grating, and the method is based on a waveguide display device of the liquid crystal polarizer grating. The waveguide display device comprises an optical waveguide, and the optical waveguide is provided with an in-coupling grating, a lower transposed grating, an upper transposed grating and an out-coupling grating which are all liquid crystal polarizer gratings; the in-coupling grating couples a light beam into the optical waveguide, and the light beam is totally reflected in the optical waveguide and enters the lower transposed grating to complete light beam expansion in the one-dimensional direction; after the light beams are expanded in the one-dimensional direction on the lower transposition grating, the light beams are refracted into the upper transposition grating, and exit pupil expansion in the other direction is completed; and the light beam is refracted into the upper transposed grating to finish exit pupil expansion in another direction, is continuously totally reflected in the optical waveguide, is forwards propagated to the out-coupling grating, and is coupled and emitted at the out-coupling grating. According to the method, the problem that a traditional grating waveguide system is small in FOV due to the narrow response bandwidth under the limitation of a traditional diffraction grating refractive index modulation degree is solved.

Description

technical field [0001] The invention relates to the field of waveguide display technology, in particular to a two-dimensional pupil expansion method based on a liquid crystal polarizer grating. Background technique [0002] As a current hotspot in the field of information display technology, the development of head-mounted augmented reality (HMD-AR) devices carries people's bright vision for future information interaction methods. As a widely recognized technical solution, waveguide-type virtual reality (Augmented Reality, AR) display devices have certain potential and advantages in terms of volume, weight, exit pupil size, and visibility. Using the principle of waveguide transmission, it can realize the replication and expansion of the exit pupil that is difficult to achieve with traditional visual optical systems, so that the wearer of the AR system can obtain a larger eye movement range. [0003] In the traditional visual optical system, the FOV and the size of the exit ...

AI Technical Summary

Problems solved by technology

[0007] The object of the present invention is to provide a two-dimensional pupil expansion method based on liquid crystal polarizer grating, which has the advantages of large viewing angle, high diffraction efficiency, wide wavelength bandwidth and large angular response range, etc., and mainly solves the problems caused by traditional grating waveguide systems. The problem of smaller FOV caused by the narrow response bandwidth under the limitation of the refractive index modulation degree of the traditional diffraction grating

Images