Optics: image projectors – Stereoscopic
Reexamination Certificate
2000-02-10
2001-01-23
Dowling, William C. (Department: 2851)
Optics: image projectors
Stereoscopic
C353S010000, C359S478000, C359S463000
Reexamination Certificate
active
06176582
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention is directed to an arrangement for the three-dimensional display or representation of scenes and/or objects based on planar layer images which have been obtained from different imaging planes which are offset with respect to the spatial depth of the scenes and/or objects.
2. Description of the Related Art
The procedures and arrangements known in the prior art for spatial representation of objects can be classified in three groups, in principle. In a first group, one of two images recorded from different viewing angles is allocated to one eye. Through suitable means, each eye is permitted to view the image allocated to it, but not the other image. These means ensure that each eye sees only the image allocated to it and are, for example, red-green spectacles, polarizing spectacles, and so forth.
It can also be ensured by means of appropriately arranged lenticular screens or prism screens such as split-image displays which split up the image that each eye is presented only with the image allocated to it.
However, a disadvantage consists in the fact that viewing positions and viewing distances are generally fixed at the outset and there is no possibility of accommodation of the eye. For this reason, viewing of the spatial representation achieved in this manner leads to fatigue. Further, the means required for viewing are sometimes quite elaborate, which increases cost.
In a second group of arrangements known from the prior art, the spatial representation is achieved in that the image and/or the projection of the image takes up volume. A substantial disadvantage in this case is that mechanically moving component assemblies are required which serve to project images at different spatial depths, for example, like rotating disks in a cathode ball, rotating LED surfaces or a rotating helix. This results in quite a high requirement of material and time and accordingly leads to unwanted costs since, on the one hand, precise manufacture is necessary for the moving component assemblies, whose movement must be carried out exactly, and, on the other hand, constructions of this type are also subject to wear resulting in increased expenditure on maintenance.
This group also includes a three-dimensional display device according to JP 62-77794 A which is formed from an image display device, a group of many fine, convex lenses with adjustable focal length, and another convex lens located opposite to the group of fine convex lenses. For example, the fine convex lenses are liquid crystal lenses with adjustable focal length, wherein control signals based on image depth information are applied to these lenses. When this arrangement is operated, various two-dimensional images, namely, images extending in the horizontal and vertical directions, are displayed on the image display device and can be viewed through the additional convex lens through corresponding control of the liquid crystal lenses or adjustment of focal lengths associated with the images so as to form an image which can be perceived in a three-dimensional manner.
However, the relatively elaborate optical-mechanical and optical-electronic construction and the rather large resulting constructional depth of 90 cm are disadvantageous. Also, an unwanted effect which is expected to occur is that the eye accommodated to large distances favors the raster of fine convex lenses or the raster of intermediate spaces between these lenses and does not perceive an undisturbed three-dimensional representation, which is what is actually desired. Further, the intended use on TFT displays (for miniaturization) may encounter problems, e.g., because of an unrealizable linear magnification of the optical system comprising the fine convex lenses and the additional convex lens.
Further, JP 07-64 020 A describes a three-dimensional display and a method for displaying by means of this display. According to this reference, three-dimensionally moving images can be displayed quickly and simply and can be viewed without spectacles in a large space.
For this purpose, there is a plurality of display elements which are outfitted with a convex lens having a short focal length, a light source and a stretching mechanism located between the lens and light source and which are arranged on a display surface. A three-dimensional image is generated in that the distance between the convex lenses and the light sources is changed by actuating the stretching mechanism, so that the position of the image of the light source formed by the convex lens is displaced. A three-dimensional image is formed by specifically changing the position of the virtual and real images of the light sources.
Apart from a construction which is also rather complicated in this case, a further disadvantage consists in that the aperture aberration of the convex lenses themselves is not corrected, resulting in low-quality imaging and small differences in image depths.
In a third group, images are imaged in volume. This is achieved, for example, by an acoustic-modulated concave mirror, computer-generated holograms using an acousto-optic modulator or making use of mercury vapor fluorescence by infrared excitation. These methods and arrangements are relatively complicated and therefore costly.
OBJECT AND SUMMARY OF THE INVENTION
Against this background, it is the primary object of the invention to provide an arrangement for the three-dimensional reproduction of scenes and/or objects in which imaging is carried out without projection surfaces and without the use of moving component assemblies and which requires no additional auxiliary means for the observer.
According to the invention, this object is met in that a plurality of imaging elements are provided adjacent to one another vertical to the viewing direction of an observer, wherein the imaging elements are positioned relative to one another in a planar raster of lines and columns. In this connection, at least two of the imaging elements adjacent to one another in a line and in a column of this raster have focal lengths which differ from one another and the quantity of different focal lengths corresponds to the quantity of imaging planes which are offset in spatial depth. Further, imaging elements with the same focal length are always associated with the same imaging planes. A part of a layer image is positioned in the optical axis of every imaging element, wherein portions of the same layer image are always provided in the beam path of imaging elements of identical focal length.
Therefore, it is achieved in an advantageous manner that scenes and objects of which a plurality of layer images have been recorded from different imaging planes can be spatially reproduced by simple means. This is carried out in that the individual layer images are imaged by the respective correlated imaging elements in the focal plane corresponding to their imaging plane.
In a special arrangement of the invention, it can be provided that the parts of the layer images correlated with the imaging elements are positioned in the image planes of the imaging elements. Accommodation of the observer's eye is therefore facilitated; the individual layer images are perceived with good sharpness and accordingly convey a real three-dimensional impression of the represented object.
A good resolution can be achieved when the imaging elements are arranged in sufficient quantity so as to be distributed over the raster. Imaging elements with identical focal lengths should advantageously be positioned equidistant from one another. For the observer, the layer images are nested one inside the other and each individual layer image is shown in the imaging plane allocated to it; the layer images made available for simultaneous observation accordingly convey a good spatial impression of the object to be represented or of a scene.
The essential advantage of this arrangement consists in that moving optical elements are not required. Further, in contrast to the prior art, the spatial impression is also formed when observing with only one
4D-Vision GmbH
Dowling William C.
Reed Smith LLP
LandOfFree
Three-dimensional representation system does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Three-dimensional representation system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Three-dimensional representation system will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2532555