Optical: systems and elements – Holographic system or element – Using a hologram as an optical element
Reexamination Certificate
2000-09-18
2003-05-13
Robinson, Mark A. (Department: 2872)
Optical: systems and elements
Holographic system or element
Using a hologram as an optical element
C359S460000, C359S641000
Reexamination Certificate
active
06563612
ABSTRACT:
FIELD OF THE INVENTION
The present invention, in general, is directed to the field of collimator devices.
Further in reference to the field, the present invention is directed to a collimating screen simulator which is used in connection with a projector which is preferably located behind the simulator in relation to a viewer.
Still more particularly, the present invention is also directed to a method for using the collimating screen simulator, which is disclosed in detail herein, for simulation of an object and, thereafter, for displaying the object at an infinitely distant position.
BACKGROUND OF THE INVENTION
In principle, a “perfect” collimator is a device for producing a beam of precisely parallel rays (as of light) or for forming an infinitely distant virtual image which can be viewed without parallax. Furthermore, in the field of the invention, the term “parallax” is well understood by those skilled artisans of the field to mean the apparent displacement, or the difference in apparent direction, of an object as seen from two different points which are not on a straight line with the object.
Historically, the manufacturers of collimator devices have relied upon lenses of various shapes and surface curvatures, including combinations of such lenses, to achieve a desired effect. As a result, conventional collimator devices frequently have been bulky and/or may have possessed significant weight, with specialty plastics currently replacing glass to obtain a desired advantage. Yet, current technology is economically impractical for large-scale applications that require an unbroken collimating effect over a large area. It is therefore currently desirable to further reduce the volume and mass of collimators.
Moreover, conventional collimator devices are not perfect with the result that an image which is projected onto a screen appears to come from the screen. In other words, since the projected image appears on the movie screen, the viewer focuses his/her eyes on the screen. Amazingly, this is viewed as a “problem” by those in the entertainment field, where every attempt is made to take the theater-goer out of the “environment” of the theater and place him/her into the “environment” of the entertainment being viewed.
In the entertainment field, to simulate virtual “reality” for theater-goers, it would therefore be desirable to create a virtual “window” onto which an image is projected, so the projected image appears to come from a quasi-infinite distance behind the “window,” meaning that the screen is no longer noticed by the viewer. Rather, the viewer focuses on objects that may appear to be just behind, or extremely far behind, the invisible window.
Thus, even more practical virtual “reality” applications for the present invention involve the fields of simulators for training pilots, navigators and other aircraft personnel.
There are, however, significantly broader applications for the present invention, which utilize principles of virtual “reality” in, e.g., the technical areas of medical training, outer space and under-the-sea simulation, an assortment of fantasy-based devices as well as other general amusement-based devices including video arcade and gaming devices.
Furthermore, holographic displays can be reconstructed from a collimated beam, as noted in U.S. Pat. No. 5,886,675 to Aye et al., assigned to Physical Optics Corporation. On the other hand, and to the best of our combined knowledge prior to our present discovery, we had never read or heard of anyone using a holographic screen to produce a collimated beam, which is the essence of our present discovery. In other words, in view of recent advances in technology relating to ever sleeker, trimmer and lighter holographic screens, where much of the present state-of-the-art technology results from our efforts at Physical Optics Corporation, it struck us that a holographic screen may have a heretofore unappreciated utility, especially in connection with the production of collimated beams, in view of the present desire to achieve an unbroken collimating effect over a large area.
SUMMARY OF THE INVENTION
The present invention may be summarized as a collimating screen simulator comprising a projector and a holographic diffuser screen. The projector is adapted to project a viewable image onto a focal plane that is spaced from the projector.
The focal plane has a backside and a viewing side opposite the focal plane backside. In operation, the projector projects the image onto the focal plane backside. The holographic diffuser screen is adapted to permit light from a source and incident upon a surface of the diffuser screen to pass through the screen. The holographic diffuser screen has a first surface facing the focal plane viewing side for receiving the incident light and a second surface opposite the first surface. The holographic diffuser screen is spaced from the focal plane viewing side by a distance effective for enabling a viewer facing the second surface of the holographic diffuser screen to see collimated light exiting the holographic screen. In reference to the collimating screen simulator, the holographic diffuser screen preferably includes at least a substrate and a film hologram applied to the substrate. Further in this regard, the substrate is preferably either plastic or glass. Still further in this regard, if the substrate is of plastic, such plastic is preferably polycarbonate.
Still referring to the collimating screen simulator, the substrate is preferably about 1 millimeter to about 6 millimeters thick, more preferably about 2 millimeters to about 5 millimeters thick, and still more preferably about 3 millimeters to about 4 millimeters thick. Furthermore, the film hologram preferably has a thickness that ranges from about 5 microns to about 50 microns. More preferably, the film hologram has a thickness that ranges from about 10 microns to about 40 microns, and still more preferably that ranges from about 15 microns to about 35 microns.
In reference to conventional viewing simulators, the projected image appears on the viewing screen, and the viewer focuses his/her eyes on the screen.
In reference to the invention, however, the viewer (not aware of the screen) is in fact focusing his/her eyes at “infinity” which those skilled in the field of the invention know as “optical” infinity (understood to be a distance of about 300 feet from the viewer) which differs from the mathematically-precise “infinity” as defined by optical principles.
A method for displaying an image at a distance defined hereinabove as “optical” infinity may be summarized as follows. Such a method comprises the step of interposing between a viewer and a projector spaced from the viewer the holographic diffuser screen.
These and other aspects and features of the invention will readily be apparent to those skilled in the art upon reference to the detailed description and following figures.
REFERENCES:
patent: 4586780 (1986-05-01), Chern et al.
patent: 4960314 (1990-10-01), Smith et al.
patent: 5886675 (1999-03-01), Aye et al.
patent: 6095652 (2000-08-01), Trayner et al.
Aye Tin M.
Savant Gajendra D.
Yu Kevin H.
Amari Alessandro V.
Physical Optics Corporation
Robinson Mark A.
Tachner Leonard
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