Dynamically controlled focal plane for optical waveguide-based displays

Abstract

Embodiments of the disclosure provide systems and methods for providing a dynamically variable focal plane in a waveguide-based display. Generally speaking, embodiments described herein provide an optical system that allows variable control of the focal length of the image emerging from the display engine into the waveguide. This can be a dynamic system that is controlled based upon the content being projected on the display. For a stereoscopic system, individual control of each eye can be provided. More specifically, embodiments comprise an electrically tunable lens element interposed between the output of the projection engine and the optical waveguide and a control unit to dynamically the tunable lens element to vary the focal length of the images provided to the waveguide display.

Description

FIELD OF THE DISCLOSURE[0001]Embodiments of the present disclosure relate generally to methods and systems for display devices and methods and more particularly to augmented reality and mixed reality waveguide-based display devices and methods providing a dynamically variable focal plane.BACKGROUND[0002]The optical waveguide has become a common element in heads up displays used in Augmented Reality (AR) and Mixed Reality (MR) devices. As the waveguide technology matures it is likely to also play a role in Virtual Reality (VR) devices. Such displays are commonly referred to as a Near-Eye Display (NED). In these systems, there are two major components: a projection engine which renders either a raster or vector based mono or full color image into a small aperture; and a waveguide that takes that image from the display engine and projects it across a larger surface which faces the user's eye. In AR and MR applications, the waveguide forms a lens that can display both the image generate...

AI Technical Summary

Benefits of technology

This patent describes a control system for a display device that uses a variable lens element to adjust the rendering of images on a waveguide display element. The control system can use a deformable lens with multiple control locations. The control unit can maintain a predefined set of control parameters and apply a nonuniform force to the lens through the control locations to compensate for misalignments. This allows for improved control of the variable lens and better adjustment of the image quality. Overall, the control system can enhance the performance and quality of the display device.

Problems solved by technology

The first limitation is that the virtual image displayed by the waveguide has a fixed focal length with images on the display typically appearing to the user as a large flat display suspended in one fixed space location approximately between 0.5 meters to 10 meters in front of the user.

While this may be suitable for some content, e.g., documents for reading, a fixed focal plane is problematic for more detailed graphical structures designed to reside in the augmented reality space—either in the near field or far field.

Directly related to this is a second issue whereby the image may not be in focus to people with vision impairment such as near or far sightedness.

The second problem occurs when a far-sighted user is presented with detail images 0.5 meters away.

Typically to solve this problem, the user is required to wear prescription lenses along with the AR device which can be cumbersome and present other negative optical issues such as glare, reflection, color aberrations, tilt, etc.

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