DTI has demonstrated new optical configurations designed to project autostereoscopic images to very large sizes using only one display and projector. They will allow the creation of large (50 cm and greater) immersive high resolution autostereoscopic displays with advanced features like head tracking and/or look around imaging. Previous autostereoscopic projection devices have used multiple displays in combination with multiple projectors, with attendant complexity and expense. The basic technique uses a small LCD to create viewing zones within a single large projection lens, of the type normally used for projection television applications. The lens images the LCD onto a large Fresnel lens. The Fresnel lens in turn re-images the viewing zones into the space in front of it. In this arrangement, the viewing area is limited to roughly twice the size of the lens that is used for projection. Methods used to expand the viewing area will be described.
Over the past two years, DTI has developed technology under an SBIR program designed to create advanced autostereoscopic hologram-like displays yielding multiple full resolution perspective images that can be viewed passively by multiple observers across a wide area. The first prototype display of this type was completed in 1994. It demonstrated three key technologies necessary for the practical embodiment of an advanced commercial flat panel autostereoscopic display. (1) A fast surface mode LCD capable of displaying 180 images per second with many gray levels. (2) An interlaced light line illumination system that is responsible for making different images visible from different regions of space in front of the display, and allows flicker free imaging at near 30 fps. (3) A controller designed to accept perspective images in standard formats, interlace them, and display them on the LCD. These technologies are demonstrated on an 800 X 400 LCD with 32 true gray shades, yielding up to six perspective views every 33 ms. At half resolution it would be possible to generate twelve views. The system is driven by an entry level workstation and could also accept input from multiple cameras, given the right interface. Results of the project and plans for the future will be discussed.
Dimension Technologies Inc. has devised and experimentally validated a technique for producing field-sequential-color illumination for liquid crystal displays (LCDs) that does not exhibit image breakup and can provide flicker free images at slower refresh speeds than other field-sequential-color techniques. The technique involves a combination of colored illumination patterns that are sequentially imaged within the pixels of an LCD. An optical bench version of this type of illumination system was used to evaluate the ability to produce white light, evaluate flicker performance, evaluate image breakup visibility, and perform reading tests. This work can lead to a superior means of producing color displays using monochrome LCDs. Application of the research by LCD manufacturers may allow that industry to produce simplified, less costly LCDs for color displays.