3D Display Device
Publication Date: 2003-Jul-18
The IP.com Prior Art Database
The invention relates to an auto stereoscopic 3D display device. In a conventional 3D-LCD
display, small lenses are put in front of an otherwise normal LCD. Each lens
covers a small number of pixels to transmit image information of some of them
towards the left eye and some to the right eye. As a result, viewing angles
cannot be very big, e.g. 15° for
a 3D-LCD design, and 30° for
the 3D CRT design. According to the invention a faceplate technique can be
applied in an auto stereoscopic display device in order to increase the viewing
In general, face plate techniques are applied for compensation of imaging errors in lens systems. Lenses form the basis of most optical imaging systems such as cameras, projectors and optics in 3D displays. The stronger the lenses, the more they suffer from aberrations. Especially in wide viewing-angle applications, strong lenses are needed, and the aberrations become substantial at the viewing boundaries.
Figure 1 shows the aberrations in wide viewing-angle optical systems . The image plane and the focal surface are different; causing the image to be unsharp at the boundaries. The problem of the optical system shown in Figure 1 is that the image plane is flat, while the lens has a curved focal surface that is flat only locally in the center. The invention proposes to use a so-called faceplate with a surface profile as interface between the two surfaces.
Fig. 2 shows a face plate accommodating for the difference between the image plane and focal surface.
Fig. 3 shows a curved faceplate transporting light from the top surface to the bottom surface, in a practically straight vertical direction. The device according to the invention is based on the observation that an image is transferred 1:1 over a finite distance by making use of the faceplate. A way to make faceplates is by bundling a high number of small fibers. Each fiber has a core with high refractive index, and a skin of low refractive index. In this way, the skin acts as mirror. A composite containing many wave guides transports incoming light, here drawn from the top, without significant horizontal displacement, to the bottom plane of the plate. The diameter of each wave guide determines the maximum optical r...