Computer graphics processing and selective visual display system – Plural display systems – Tiling or modular adjacent displays
Reexamination Certificate
1995-01-12
2001-03-27
Chang, Kent (Department: 2778)
Computer graphics processing and selective visual display system
Plural display systems
Tiling or modular adjacent displays
C348S052000
Reexamination Certificate
active
06208318
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a system and method for a high resolution, fully addressable volumetric display using a planar array.
2. Brief Description of the Prior Act
It has been known in the prior art to modulate or scan a beam, such as a laser beam, and then to project the scanned beam onto a screen. Examples of such systems are set forth in the Brief Description of the Prior Art in Garcia, Jr. et al. U.S. Pat. No. 5,042,909 and as well as in that patent. The prior art listed hereinbelow is incorporated herein by reference.
Such autostereoscopic volumetric display systems and methods have been described in the prior art and include a vertical planar screen rotated about a vertical axis, a first mirror located away from the vertical axis facing and below the screen which is also rotated with the screen about the same vertical axis and a second mirror located on the same rotational vertical axis, rotated with the screen and the first mirror and tilted so that an image projected parallel to the vertical axis is reflected from the second mirror to the first mirror and from the first mirror to the screen. The disclosures in the patents to Solomon (U.S. Pat. No. 4,983,031), Garcia (U.S. Pat. No. 5,042,909) and Botchko (U.S. Pat. No. 5,148,310) are exemplary of such prior art. Methods of generating such images using one or more scanned serial light sources are also described in the prior art as exemplified by the disclosures in the above mentioned Garcia and Botchko patents. Transformations are further described which translate a serial light beam input into flat images which are subsequently projected onto various display surfaces, this being exemplified in the disclosures of each of the above-mentioned patents.
Image sources described in the prior art comprise serial light sources where a light beam is cut into slices and projected onto the display. This limits the ability of the prior art to generate an image with resolution sufficiently high to be useful or to place a sufficient number of points of light simultaneously onto the display screen. The term “simultaneously” is defined herein as—appearing to the viewer to be simultaneous—even though the points of light are not initially generated simultaneously in time. Defects inherent in the prior art as described hereinabove include distortion, focus and image rotation errors.
The prior art also describes gas ion laser image sources which cannot generate full color images. Generating any color other than red, green or blue requires illuminating the same physical location simultaneously with more than one laser (in the case of a multicolor system including colors other than the primary colors). For example, a yellow point requires both a red and a green laser. To accomplish this, first, multiple lasers must be very precisely aligned to generate a single point. Voltage controlled oscillators or scanners suffer from both non-linearities of positioning and electrical drift. This, in essence, prevents the perfect alignment of multiple image sources which is necessary to generate nonprimary colors. Second, using two or more points of laser light to generate one viewable spot significantly reduces the number of points of light available to form an image, further reducing the resolution of the display.
One well known problem with volumetric displays is selection of the viewing perspective from which to display text and other two-dimensional symbology or icons. Although the volumetric image may be both viewable and useful from all aspect angles, it is impossible to pre-select the position of the viewer. Furthermore, doing so would obviate the usefulness of a volumetric display which can be viewed from all sides. This problem is not addressed by the prior art.
SUMMARY OF THE INVENTION
In accordance with the present invention, the aforementioned problems inherent in the prior art as well as other problems are overcome or minimized. There is provided a three-dimensional, full color, fully addressable high resolution display system. The system generates three-dimensional images by projecting light beams onto a rotating surface. The size of the spinning surface defines the projectable volume. Points are plotted in a pre-defined two-dimensional space (x-y, z-r or other coordinate system). The flat images are projected against the spinning display surface using mirrors and lenses. When the light beams strike the display surface, the surface diffuses the beam to form a point. By timing the light beams as the rotating surface sweeps through the display volume, the light patterns allow viewers to perceive a three-dimensional image.
A planar light array is controlled to place multiple beams of light simultaneously onto the display surface, enabling high resolution images to be generated. Unlike gas-ion laser systems described in the prior art, the system can generate full color images. In the preferred embodiment, three planar arrays are used, with a white illumination source and filters or dichroic beam splitters to separate the incoming light into red, green and blue components. In a second embodiment, three planar arrays are used, each with a separate illumination source. The illumination sources or lamps are red, green and blue, respectively. In a third embodiment, a tri-colored wheel (red, green, blue) is used with a white illumination source and image generation is timed to generate full color images. Because all of the elements of the array of the first and second embodiment can be used simultaneously to place light onto the display surface, generating full color displays does not reduce the points of light available for the images.
Volume display system practice is refined and extended by defining a system which corrects defects inherent in the prior art, including distortion, focus and image rotation errors by defining a modular, optical system which allows the effective interface of various image sources, including non-scanned planar arrays, to display devices of various configurations and by defining a configuration in which the first rotating mirror may be replaced by a fixed toroidal mirror, further simplifying the mechanical complexity. An auxiliary display can be provided to augment the three-dimensional images with text. This auxiliary display may be positioned anywhere around the circumference of the volumetric display.
An image is projected along an optical axis which is parallel to the rotation axis. For mechanical practicality, it is desirable to minimize the size of the first rotating mirror to reduce the moment of inertia that must rotate and to minimize the diameter of the optics below the second mirror so that a shaft may be formed which can be supported by through-mounted bearings of minimum size. In order to satisfy these constraints, a pupil must be formed by the optics at or near the second mirror. For mechanical convenience, the optics within the shaft will rotate with the mirrors and screen, but are not required to do so. Due to the configuration of the rotation axis with respect to the projected image, the image will appear to rotate about the center of the screen. A planar image source of fixed pixel arrangement will not generally be used efficiently in this case, because the array must be oversized to allow for the image rotation. In this situation, optical means for derotation of the various configurations such that they contain an odd number of reflections, is rotated about the optical axis in such a way as to counteract the image rotation induced by the rotation of the original mirrors and screen. Alternatively, image sources which do not necessarily include a fixed pixel pattern may correct for image rotation optically as above or electronically or in software.
For aesthetic reasons, the first mirror is placed below the rotating screen in order to avoid entering the line-of-sight of the viewer. As a result, the screen is effectively tilted with respect to the original axis. This results in two defects. First, the image cannot be in focus throughout the full scr
Anderson Douglas W.
Fisher Thomas Drew
Hatch Gregory A.
Spiegl Christine R.
Wright Tommy Dean
Baker & Botts L.L.P.
Chang Kent
Raytheon Company
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