Optics: image projectors – Stereoscopic
Reexamination Certificate
1999-05-25
2001-02-06
Dowling, William (Department: 2851)
Optics: image projectors
Stereoscopic
C359S477000, C359S478000, C353S010000
Reexamination Certificate
active
06183088
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to display screens for three-dimensional display systems, and to display systems which employ such display screens.
Multiplanar three-dimensional (hereinafter “3-D”) displays produce 3-D imagery by illuminating a target surface undergoing periodic motion.
FIG. 1
shows an example of such a target. In operation, display target
1
rotates (or “sweeps”) about axis
2
through a 3-D display volume
4
. One or more light sources (not shown) are used to project one-dimensional (hereinafter “1-D”) or two-dimensional (hereinafter “2-D”) images onto surfaces
5
and
6
of display target
1
as it rotates. These images, coupled with the persistence of human vision, cause a volume-filling (or “volumetric”) 3-D image
7
to be perceived by a viewer as display target
1
rotates.
Conventional multiplanar 3-D displays produce “edge-on” dark regions wherever sections of the display target are coplanar with a viewer's line of sight.
FIG. 2
, which is a top view of display target
1
, illustrates this phenomenon. As shown, a viewer at location
9
will perceive a dark region in a resulting 3-D image due to insufficient light emanating from the screen in the viewer's line of sight
8
.
SUMMARY OF THE INVENTION
One aspect of the invention alters the geometry of a 3-D display target so as to reduce the amount of edge-on darkness perceived by a viewer. To this end, the display target of the present invention includes tapered edges, as opposed to conventional flat edges. For example, the display target may have a “diamond-shaped” cross-section or, more generally, any type of cross-section having tapered edges. By including tapered edges on the display target, it is possible to reduce the amount of the display target's edge that is in a viewer's line of sight, and thereby reduce the amount of edge-on dark regions in a resulting 3-D image.
Another way to reduce edge-on darkness is to make the display target “ultra-thin”, e.g., on the order of one millimeter (1 mm) or less. Use of an ultra-thin display target also reduces the amount of display target edge that is in a viewer's line of sight, and thus also reduces edge-on dark regions in resulting 3-D images. To reduce edge-on darkness even further, tapered edges may be included on an ultra-thin display target.
Heretofore, the use of an ultra-thin display target such as that described above was impractical due to its inherent instability at the frequencies of rotation required for 3-D imaging. In accordance with another aspect of the invention, the ultra-thin display target is embedded inside a translucent host which provides the display target with the stability necessary for 3-D imaging. In this regard, to enhance stability and reduce the deleterious effects of air resistance and imbalance on a resulting image any display target described herein may be embedded in such a translucent host.
In general, in one aspect the invention features a display target which receives a projected image (e.g., 1-D and/or 2-D images) and which rotates about an axis to form a 3-D image from the projected image. The display target includes front and back surfaces that meet at locations relative to the axis to form tapered edges.
In preferred embodiments, the display target includes one or more of the following features/functions: The front and back surfaces meet at distances from the axis to form tapered side edges of the display target. The front and back surfaces meet along the axis to form tapered top and bottom edges of the display target. A thickness of the display target at each tapered edge is less than a thickness of the display target between opposing tapered edges, with thickness being defined by a distance between the front and back surfaces. A cross-sectional area of the display target taken parallel to the axis is substantially diamond-shaped or substantially convex or concave in shape. A cross-sectional area of the display target taken perpendicular to the axis is substantially diamond-shaped or substantially convex or concave in shape. The front and back surfaces are substantially rectangular or helical. The display target is comprised of a molded plexiglass screen and/or is embedded in a translucent host.
In general, in another aspect the invention features a display apparatus for use in a 3-D display system. The display apparatus includes a translucent host and a display target embedded inside the translucent host. The display target receives a projected image and rotates while inside the translucent host to form a 3-D image from the projected image. At least a portion of the display target has a thickness on the order of one millimeter (1 mm) or less.
In preferred embodiments, the display apparatus includes one or more of the following features/functions: The translucent host is a translucent cylinder, and the display target is embedded in the translucent cylinder. The display target is substantially rectangular or helical. The display target rotates about an axis to form the 3-D image, and includes front and back surfaces that meet at locations relative to the axis to form tapered edges. A cross-sectional area of the display target taken either parallel to, or perpendicular to, the axis is substantially diamond-shaped or substantially convex or concave in shape. The display target is a layer of paint or any other type of reflective/diffusive substance embedded inside the translucent host.
In general, in still another aspect the invention features a 3-D display system that includes a display target which receives a projected image and which rotates about an axis to form a 3-D image from the projected image. The display target has front and back surfaces that meet at locations relative to the axis to form tapered edges. Scanning optics directs light to the display target to form the projected image. A controller controls operation of the display target and the scanning optics.
In general, in still another aspect the invention features a 3-D display system that includes a translucent host and a display target embedded in the translucent host. The display target receives a projected image and rotates about an axis to form a 3-D image from the projected image. At least a portion of the display target has a thickness on the order of one millimeter (1 mm) or less. Scanning optics directs light to the display target to form the projected image. A controller controls operation of the display target and the scanning optics.
Advantages of the invention in addition to those set forth above will become apparent in view of the following description, including the figures, and the claims.
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Favalora Gregg E.
Giovinco Michael G.
LoRe Andrew G.
Actuality Systems, Inc.
Dowling William
Fish & Richardson P.C.
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