Near-eye display with self-emitting microdisplay engine
A near-eye display for an augmented reality display system couples a self-emitting microdisplay to a transmissive waveguide through an input coupler. Light from the self-emitting microdisplay propagates along the waveguide and through an output coupler for generating a virtual image that is visible together with a real-world scene through the waveguide within an eyebox located in front of the output coupler. A light sensor detects light levels within different portions of the real world scene visible within the eyebox. Drive electronics control the light output from individual pixels of the self-emitting microdisplay to preserve desired local contrast values between the virtual image and the real-world scene.
1. A compact, power-saving near-eye display comprising:
a transmissive waveguide including an input coupler and an output coupler,
the transmissive waveguide having an optically transmissive substrate with parallel front and back surfaces,
a self-emitting microdisplay system for generating images having a two-dimensional image light source comprising an array of pixels with each pixel of the two-dimensional image light source being a self-emitting light source that emits light as a function of power applied to each self-emitting light source,
the two-dimensional image light source being supported on one of the parallel front and back surfaces of the optically transmissive substrate in an orientation for directing the emitted light away from the optically transmissive substrate,
a folded optic for reflecting the emitted light back toward the optically transmissive substrate to the input coupler;
the input coupler being arranged for directing the reflected light into the optically transmissive substrate for propagation by internal reflections from the parallel front and back surfaces along the optically transmissive substrate to the output coupler, and
the output coupler being arranged for directing the internally reflected light out of the optically transmissive substrate to an eyebox with which the images generated by the self-emitting microdisplay system are visible as virtual images together with a real-world scene through the parallel front and back surfaces of the transmissive substrate.
2. The display of claim 1 in which the folded optic supports successive reflections of the emitted light in two directions for propagation through a positive lens to the input coupling.
3. The display of claim 2 in which the folded optic is a prism-shaped reflecting structure.
4. The display of claim 1 in which the two-dimensional image light source is mounted in a coplanar fashion on one of the parallel front and back surfaces of the optically transmissive substrate.
5. The display of claim 4 in which in which the two-dimensional image light source is mounted is mounted in a fashion that forms an air gap between the two-dimensional image light source and the optically transmissive substrate to support the propagation of the reflected light by internal reflections from the parallel front and back surfaces.
6. The display of claim 4 further comprising a heat sink between the two-dimensional image light source and the one of the parallel front and back surfaces of the optically transmissive substrate.