US Patent 7355795 Head-up display device with curved optical surface having total reflection

A display device for displaying information is provided with an optical system for guiding the light of the display device to the eye, the optical system having, in the order in the proceeding direction of the light, an entrance face for receiving the light, a curved face for totally reflecting the light and a reflecting face concave to the eye side and adapted to reflect the light toward the eye. The reflected light is transmitted by the curved face and reaches the eye. Thus there is obtained a compact display device with satisfactorily suppressed aberrations.