A method for making a holographic device waveguide display device

In recent years, many researchers have been studying a holographic device waveguide structure. This structure uses a reflection-type volume holographic device grating as the input and output optical coupling components, which are mirror-symmetric. The input coupling holographic device grating and the output coupling holographic device grating are bonded to both sides of the waveguide. The display principle is that the image emitted by the microdisplay is first collimated by a collimating optical system, then diffracted by the input coupling grating into the holographic waveguide, and finally coupled into the human eye by the output holographic grating. The field of view of this holographic waveguide display configuration is mainly determined by the collimating optical system and the angle and wavelength bandwidth of the volume holographic grating. However, the angular selectivity and wavelength selectivity of the holographic device grating are very good, which limits the field of view of this waveguide display system, only reaching 10 degrees holographic device to -20 degrees. Therefore, various solutions have been proposed to expand the field of view of the holographic waveguide. Both the input and output optical coupling components are reflection-type volume holographic gratings, and the effect of expanding the field of view is not ideal, and the design and process are relatively complex. holographic device to -20 degrees. Therefore, various solutions have been proposed to expand the field of view of the holographic waveguide. Both the input and output optical coupling components are reflection-type volume holographic gratings, and the effect of expanding the field of view is not ideal, and the design and process are relatively complex. -20 degrees. Therefore, various solutions have been proposed to expand the field of view of the holographic waveguide. Both the input and output optical coupling components are reflection-type volume holographic gratings, and the effect of expanding the field of view is not ideal, and the design and process are relatively complex.
      

A holographic device waveguide display device, including a multi-angle collimating microdisplay, a lens group, a planar waveguide, an input coupling holographic optical diffraction element, and an output coupling holographic optical diffraction element; the multi-angle collimating microdisplay is located below the lens group, and the lens group is located below the input area of the planar waveguide; the input coupling holographic optical diffraction element is located in the input area of the planar waveguide, and the output coupling holographic optical diffraction element is located in the output area of the planar waveguide; the multi-angle collimating microdisplay converts a two-dimensional image into a collimated beam with multi-angle image information, and the collimated beam with multi-angle image information enters the input area of the planar waveguide after refraction by the lens group, and after diffraction by the input coupling optical diffraction element, it propagates to the output area in the planar waveguide by total internal reflection, and then the output coupling optical diffraction element diffracts the image information into the human eye. The multi-angle collimating microdisplay includes a microdisplay and a collimating optical system, where the microdisplay outputs a two-dimensional image, and the collimating optical system converts the divergent light of each pixel of the microdisplay into a multi-angle collimated beam containing image information. The planar waveguide is made of planar optical glass or planar optical resin, with a thickness of 1-15mm and a refractive index of 1.3-2.0 . The input coupling holographic optical diffraction element in the input area of the planar waveguide and the output coupling holographic optical diffraction element in the output area can be located on the upper surface, lower surface, or inside the waveguide. The lens group is a double-adhesive lens group or a group of convex-concave lenses with different focal lengths and apertures. The input coupling holographic optical diffraction element and the output coupling holographic optical diffraction element are transmission-type volume holographic gratings, reflection-type volume holographic gratings, transmission-type volume holographic lenses, or reflection-type volume holographic lenses. The thickness of the input coupling holographic optical diffraction element and the output coupling holographic optical diffraction element is 5-25um and the recording holographic material is silver halide, dichromated gelatin, photopolymer, photoresist, or photorefractive glass. The diffraction efficiency of the input coupling holographic optical element is 90 % or more, and the diffraction efficiency of the output coupling holographic optical element is 20 % -50 %. The distance between the input coupling holographic optical element and the output coupling holographic optical element is 50-100mm。
    holographic device The waveguide display device is based on the principle of a traditional telescope optical system, combined with a holographic waveguide structure, transforming a coaxial telescope system into an off-axis optical system suitable for see-through head-mounted displays. This solves the problems of small field of view and small exit pupil in traditional holographic waveguide display devices, and has the advantages of simple and compact optical structure, easy preparation and processing, low cost, and light weight.