Diffractive display system with adjustable IPD

A display system for accommodating different interpupillary distances (IPDs), the display system comprising:

• a waveguide plate comprising opposing parallel surfaces, the waveguide plate further comprising an in-coupling grating, an expansion grating, and an out-coupling grating;
• wherein:
• the in-coupling grating is configured to diffract input light received from a projection system to cause total internal reflection of the input light within the waveguide plate via the opposing parallel surfaces of the waveguide plate,
• the expansion grating is configured to (i) cause replica expansion of the input light and (ii) cause the input light to propagate within the waveguide plate toward the out-coupling grating,
• the out-coupling grating is configured to (i) cause replica expansion of the input light replica expanded by the expansion grating and (ii) diffract the input light replica expanded by the expansion grating outward from the waveguide plate,
• the in-coupling grating is configured to receive the input light from the projection system at a plurality of translational positions of the waveguide plate relative to the projection system, and
• for each translational position of the waveguide plate relative to the projection system, less than about 70% of the in-coupling grating diffracts the input light to cause internal reflection of the input light within the waveguide plate.

A head-mounted display (HMD) for accommodating different interpupillary distances (IPDs), the HMD comprising:

• a first display system, the first display system comprising:
• a first waveguide plate comprising first opposing parallel surfaces, the first waveguide plate further comprising a first in-coupling grating, a first expansion grating, and a first out-coupling grating;
• a first projection system configured to direct first input light toward the first in-coupling grating;
• and
• a first translation assembly configured to translate the first waveguide plate relative to the first projection system along an axis,
• wherein:
• the first in-coupling grating is configured to diffract the first input light to cause total internal reflection of the first input light within the first waveguide plate via the first opposing parallel surfaces of the first waveguide plate,
• the first expansion grating is configured to (i) cause replica expansion of the first input light and (ii) cause the first input light to propagate within the first waveguide plate toward the out-coupling grating, and
• the first out-coupling grating is configured to (i) cause replica expansion of the first input light replica expanded by the first expansion grating and (ii) diffract the first input light replica expanded by the first expansion grating outward from the first waveguide plate for viewing by a first eye of a user operating the HMD;
• and
• a second display system, the second display system comprising:
• a second waveguide plate comprising second opposing parallel surfaces, the second waveguide plate further comprising a second in-coupling grating, a second expansion grating, and a second out-coupling grating;
• a second projection system configured to direct second input light toward the second in-coupling grating;
• and
• a second translation assembly configured to translate the second waveguide plate relative to the second projection system along the axis,
• wherein:
• the second in-coupling grating is configured to diffract the second input light to cause total internal reflection of the second input light within the second waveguide plate via the second opposing parallel surfaces of the second waveguide plate,
• the second expansion grating is configured to (i) cause replica expansion of the second input light and (ii) cause the second input light to propagate within the second waveguide plate toward the out-coupling grating, and
• the second out-coupling grating is configured to (i) cause replica expansion of the second input light replica expanded by the second expansion grating and (ii) diffract the second input light replica expanded by the second expansion grating outward from the second waveguide plate for viewing by a second eye of a user operating the HMD.