Patent ID: 9599813
Date: 2017-03-21
CPC Classifications: B64D,G02B,G02F

Claim:
1. A head up display for use in a cockpit and for providing light from an image source, the head up display comprising: a waveguide comprising a first waveguide portion physically coupled with a second waveguide portion, the first waveguide portion having a first end and disposed under and parallel to a top surface of a glare shield, the second waveguide portion having a second end and disposed at an angle with respect to the top surface of the glare shield, the waveguide having a first coupler at the first end and a second coupler at the second end, the waveguide positioned as a combiner and allowing viewing of an outside scene and information from the image source, the waveguide configured to cause light associated with the information to travel by total internal reflection from the first end to the second end, the waveguide having a glare reducer attached to the second waveguide portion and disposed between a surface of the waveguide and a windshield of the cockpit or between the surface of the waveguide and a ceiling of the cockpit, wherein the glare reducer is a directional diffuser configured to diffuse ambient light that enters the cockpit through the windshield before the ambient light enters the waveguide so that the ambient light enters the waveguide and travels through the waveguide towards the second coupler at an incident angle that causes the ambient light to diffract away from an eye motion box of a pilot upon exiting the waveguide, thereby reducing sunspot imaging via diffraction through the second coupler.