Collapsible overhead projector
Epi-illumination type projection device
Episcopic projector
Episcopic projector
Foldable optical apparatus
Low profile episcopic projector
Low profile episcopic projector and opaque materials therefor
Method and projection apparatus
Off axis fresnel reflector for liquid crystal display
Opaque projector
Opaque projector
Opaque projector
Overhead projector
Overhead projector
Overhead projector
Overhead projector
Overhead projector
Overhead projector with centerless Fresnel lens reflective stage
Portable opaque projector
Projecting optical apparatus having no trapezoidal distortion