Methods and systems for displaying stereoscopy with a freeform optical system with addressable focus for virtual and augmented reality
Several unique hardware configurations and methods for freeform optical display systems are disclosed. A freeform display system includes primary freeform optical element(s) and secondary freeform optical element(s) in tiled arrangements to expand the horizontal field of view (FOV) or the vertical field of view. The system may include a variable focusing system that produces intermediate pupil and changes the focal distance of a single focal plane or switches among multiple focal planes for rendering objects in focus while resolving accommodation-convergence conflict. The system may map light samples to appropriate light rays in physical space and use a cluster of projectors to project the mapped light rays to produce the light field of the virtual display content. Methods for making tiled freeform optical display systems and methods for producing virtual content with variable focus freeform optics and rendering light fields are also disclosed.
1. A method for generating a light field display with a freeform optical system, comprising:
receiving bundles of light rays from an image source to produce virtual display content for a virtual object in the bundles of light rays;
extracting information for the virtual object from the bundles of light rays, the information comprising radiances, colors, depths and directions of the light rays;
generating modulated bundles of light rays by modulating the radiances and colors of the bundles of light rays as a function of the extracted directions of the light rays;
mapping the modulated bundles of light rays of different radiances and colors to appropriate mapped light rays representing the virtual object; and
rendering the virtual display content for the virtual object by emitting the light rays from one or more image projectors through an intermediate pupil and into a freeform optical display device without using any intervening focusing elements between the one or more image projectors and the freeform optical display device.
2. The method of claim 1 , further comprising:
synthesizing the light field corresponding to the virtual object based in part or in whole upon an unaided accommodation range to address both the accommodation cue and the convergence cue with a first focal distance; and
producing the virtual display content with at least the freeform optical display device, wherein a virtual image distance of the virtual display content appearing to a human observer is equal to the first focal distance.
3. The method of claim 2 , wherein the act of synthesizing the light field is performed based at least in part upon an unaided accommodation range of a user's visual system.
4. The method of claim 2 , further comprising:
addressing both accommodation cues and convergence cues associated with the virtual display content with a variable focal distance, wherein the variable focal distance is varied by determining a distance value of a single focal plane or by switching among a plurality of focal planes having different focal distance values.
5. The method of claim 1 , wherein generating the modulated bundles of light rays by modulating the radiances and colors of the bundles of light rays is also based upon the extracted radiances, colors and depths of the light rays.
6. The method of claim 5 , further comprising:
determining where the modulated bundles of light rays are to be projected based in part or in whole upon the information extracted from the bundles of light rays;
determining which image projector is to be used to project a modulated bundle of light rays to render the virtual display content; and
identifying or determining one or more parameters for rendering the virtual object wherein the one or more parameters comprises each of: (i) radiance of the light rays in rendering the virtual object, (ii) the virtual depth of the virtual object in the virtual content display rendered by the freeform display system, (iii) the location of the part of light rays for a part of the virtual object rendered by the light rays, (iv) a required or desired resolution of the rendering of the virtual display content for the virtual object, and (v) the field of view of the freeform display device.