US Patent 7425069 Autostereoscopic multi-user display

The invention relates to an autostereoscopic multi-user display comprising a focussing element and a selectable display for the time-sequential representation of 2D and/or 3D images. When viewed in the direction of the observer, said display contains a sweet-spot unit and an image matrix, which function separately from one another. The sweet-spot unit focuses a light distribution with a large surface area onto the eyes of the observer by means of a lateral sweet-spot extension, which is greater than or equal to the distance between the eyes of the observer. The sweet-spot bundle traverses the imaging matrix completely in a uniform manner on its way to the observer(s) and is thus modulated by the image content of the image matrix. The size of the sweet spot reduces the need for tracking precision. The sweet-spot unit consists of an illumination and imaging matrix. The illumination matrix is situated approximately in the front focal distance of the imaging matrix and can consist of backlight and an electronic shutter with controllable apertures or can be another suitable component. According to one embodiment, the shutter and the image matrix are identical in their pixel and sub-pixel geometry. The imaging matrix can be a double-lenticular, holographic optical element or similar.