Waveguide gratings to improve intensity distributions

An apparatus for use in replicating an image associated with an input-pupil to an output-pupil, the apparatus comprising:

• a planar optical waveguide including a bulk-substrate that includes a first major surface and a second major surface opposite and parallel to the first major surface, and also including an input-coupler, an intermediate-component and an output-coupler;
• the input-coupler configured to couple light within a specified wavelength range and corresponding to the image associated with the input-pupil into the bulk-substrate of the waveguide and towards the intermediate-component;
• the intermediate-component configured to perform one of horizontal or vertical pupil expansion and to direct the light within the specified wavelength range and corresponding to the image towards the output-coupler;
• and
• the output-coupler configured to perform the other one of horizontal or vertical pupil expansion and to couple the light within the specified wavelength range and corresponding to the image, which travels in the planar optical waveguide from the input-coupler to the output-coupler, out of the waveguide so that the light within the specified wavelength range is output and imaged from the output-pupil;
• wherein one or more of the input-coupler or the output-coupler comprises a double-sided diffractive optical element (DOE) that includes
• a transmissive grating, that is formed in or on the first major planar surface, has a first grating period and orientation, and is configured to transmit light within the specified wavelength range, and
• a reflective grating, that is formed in or on the second major planar surface of the bulk-substrate, has a second grating period and orientation that is the same as the first grating period and orientation, and is configured to reflect light within the specified wavelength range.

A see-through, mixed reality display device system, comprising:

• a display engine configured to produce an image;
• and
• a planar optical waveguide including a bulk-substrate, and also including an input-coupler, an intermediate-component and an output-coupler any one of each of which is either formed in, on or embedded within the bulk-substrate;
• the input-coupler configured to couple light corresponding to the image into the bulk-substrate of the waveguide and towards the intermediate-component;
• the intermediate-component configured to perform one of horizontal or vertical pupil expansion and to direct the light corresponding to the image towards the output-coupler;
• the output-coupler configured to perform the other one of horizontal or vertical pupil expansion and to couple the light corresponding to the image, which travels in the planar optical waveguide from the input-coupler to the output-coupler, out of the waveguide;
• the bulk-substrate includes a first major planar surface and a second major planar surface opposite and parallel to the first major planar surface;
• wherein one or more of the input-coupler, the intermediate-component or the output-coupler comprises a double-sided diffractive optical element (DOE);
• wherein each said double-sided DOE comprises a first grating that is formed in or on the first major planar surface of the bulk-substrate and a corresponding second grating that is formed in or on the second major planar surface of the bulk-substrate;
• and
• wherein for at least one said double-sided DOE the second grating of the double-sided DOE that is formed in or on the second major planar surface of the bulk-substrate has a same grating period and orientation as the first grating of the double-sided DOE that is formed in or on the first major planar surface of the bulk substrate.