Abstract: Very high refractive index (n>2.2) lightguide substrates enable the production of 70° field of view eyepieces with all three color primaries in a single eyepiece layer. Disclosed herein are viewing optics assembly architectures that make use of such eyepieces to reduce size and cost, simplifying manufacturing and assembly, and better-accommodating novel microdisplay designs.

Abstract: A lower receiver for a firearm is disclosed that includes a trigger and hammer assemblies receiving section and a magazine well section, a raised bolt catch mount and a trigger access opening defined between the sections. The bolt catch mount includes an opening for insertion of a bolt catch mounting pin, a pin insertion relief formed at the magazine well section aligned with bolt catch mount opening. A trigger finger guide feature is defined between the trigger access opening and the magazine well section below the bolt catch mount.

Abstract: Described herein is a training device and methods of use thereof for helping a baseball batter keep both hands on the bat while swinging at a ball, thus training the batter to swing with more power, better bat control, and better discipline in taking (i.e. not swinging at) bad pitches. The device includes a right wristband and a left wristband connected by a knuckle cover which covers a portion of the batter's knuckles. The device may also include a finger strap to further ensure that the device does not rotate around the wrist or hands and become improperly positioned across the knuckles.