Abstract: An eyepiece for a head mounted display (“HMD”) includes a doublet lens that includes a first optical element and a second optical element. The first optical element has an entry surface to receive the display light from a micro display and a first coupling surface. The second optical element has an exit surface and a second coupling surface paired to the first coupling surface of the first optical element. The doublet lens is configured to direct the display light through the first coupling surface, the second coupling surface, and through the exit surface.

Abstract: An eyepiece for a head wearable display includes a light guide component for guiding display light received at a peripheral location offset from a viewing region and emitting the display light along an eye-ward direction in the viewing region. The light guide component includes an input surface to receive the display light into the light guide component, an eye-ward facing side, a world facing side, a total internal reflection (“TIR”) portion disposed proximal to the input surface to guide the display light received through the input surface using TIR, and a partially reflective portion including a partially reflective element disposed over the eye-ward facing side and a switchable reflector disposed over the world facing side. The partially reflective portion is disposed to receive the display light from the TIR portion and to guide the display light via reflections off of the partially reflective element and the switchable reflector.

Abstract: An eyepiece body of an eyepiece includes an input lens positioned to couple display light into the eyepiece body along a forward propagation path, a concave end reflector disposed at an opposite end of the eyepiece body from the input lens to reflect the display light back along a reverse propagation path, and a viewing region including a partially reflective surface that redirects at least a portion of the display light traveling along the reverse propagation path out of an eye-ward side of the eyepiece body along an emission path. The partially reflective surface is obliquely angled relative to the eye-ward side and the concave end reflector is titled relative to a top or bottom surface of the eyepiece body to collectively cause the emission path of the display light to be oblique to a normal vector of the eye-ward side in two orthogonal dimensions.

Abstract: An eyepiece body of an eyepiece includes an input lens positioned to couple display light into the eyepiece body along a forward propagation path, a concave end reflector disposed at an opposite end of the eyepiece body from the input lens to reflect the display light back along a reverse propagation path, and a viewing region including a partially reflective surface that redirects at least a portion of the display light traveling along the reverse propagation path out of an eye-ward side of the eyepiece body along an emission path. The partially reflective surface is obliquely angled relative to the eye-ward side and the concave end reflector is titled relative to a top or bottom surface of the eyepiece body to collectively cause the emission path of the display light to be oblique to a normal vector of the eye-ward side in two orthogonal dimensions.

Abstract: An eyepiece for a head mounted display (“HMD”) includes a doublet lens that includes a first optical element and a second optical element. The first optical element has an entry surface to receive the display light from a micro display and a first coupling surface. The second optical element has an exit surface and a second coupling surface paired to the first coupling surface of the first optical element. The doublet lens is configured to direct the display light through the first coupling surface, the second coupling surface, and through the exit surface.

Abstract: An eyepiece for a head wearable display includes a light guide component for guiding display light received at a peripheral location offset from a viewing region and emitting the display light along an eye-ward direction in the viewing region. The light guide component includes an input surface to receive the display light into the light guide component, an eye-ward facing side, a world facing side, a total internal reflection (“TIR”) portion disposed proximal to the input surface to guide the display light received through the input surface using TIR, and a partially reflective portion including a partially reflective element disposed over the eye-ward facing side and a switchable reflector disposed over the world facing side. The partially reflective portion is disposed to receive the display light from the TIR portion and to guide the display light via reflections off of the partially reflective element and the switchable reflector.

Abstract: An eyepiece for a head mounted display (“HMD”) includes a doublet lens that includes a first optical element, a second optical element, and a reflecting element. The first optical element has an entry surface to receive the display light from a micro display and a first coupling surface disposed opposite the entry surface. The first optical element has a first index of refraction and a first Abbe number. The second optical element has an exit surface and a second coupling surface paired to the first coupling surface of the first optical element. The second optical element has approximately the first index of refraction and a second Abbe number different from the first Abbe number. The doublet lens and the reflecting element are configured to direct the display light through the entry surface, the first coupling surface, the second coupling surface, off the reflecting element, and through the exit surface.

Abstract: An apparatus for testing the reflectivity of a material under test includes a rotating carriage, a light source, and a light detector. At least two sample units are mountable to the rotating carriage. Each sample unit includes a planar surface disposed under a portion of a hemispherical surface. The light source is mounted on a pivoting boom and generates light. The light detector is mounted to measure optical power of the light emitted from the light source and reflected from a selected one of the at least two sample units. The pivoting boom and the rotating carriage rotate through different angular positions to obtain reflectance signatures as a function of incident angles for the at least two sample units.