Patent ID: 6853491

Claim:
An optical system for presenting virtual optical images of an image source outputting light in a forward direction at a desired apparent distance comprising: (a) a first linear polarizing element oriented to receive light from said image source and output first linearly polarized light having an orientation in a first direction, said first linear polarizing element being oriented in said first direction; (b) a first elliptical polarizing member oriented in a second direction and positioned to receive said first linearly polarized light and output first elliptically polarized light, said first elliptically polarized light being oriented in a first elliptical direction; (c) a partially transparent and partially reflective focusing member positioned to receive said first elliptically polarized light and transmit a portion of said first elliptically polarized light; (d) a second elliptical polarizing member positioned to receive said portion of said first elliptically polarized light from said focusing member and transmit said portion of said first elliptically polarized light as second linearly polarized light, said second linearly polarized light being oriented in said first direction; and (e) a reflective-transmissive polarizer configured and positioned to reflect light having a linear polarization in said first direction and transmit light having a linear polarization in a direction transverse to said first direction, said second elliptical polarizing member being configured and positioned to convert linearly polarized light reflected in a rearward direction by said reflective-transmissive polarizer into second elliptically polarized light with said second elliptically polarized light being polarized in said first elliptical direction, said concave mirror being positioned to reflect in a forward direction said second elliptically polarized light as third elliptically polarized light, said third elliptically polarized light having a second elliptical direction different from said first elliptical direction, and said second elliptical polarizing member being positioned to convert said third elliptically polarized light into third linearly polarized light, transmitting said third linearly polarized light in a forward direction, said third linearly polarized light being oriented in a second direction transverse to said first direction, whereby said reflective-transmissive polarizer transmits said third linearly polarized light in a forward direction.