Claims
- 1. In combination with a vehicle windshield having generally parallel front and back faces, a horizontal radius of curvature, and a vertical slant, a reflective device designed to provide wide scope rearview to an operator of the vehicle, said device comprising:
- an elongated support adjustably mounted in a position substantially parallel to and spaced apart from a transversal upper section of the windshield back face, said section substantially spanning the full width of the windshield, said support having a outward face facing said section and an opposite inward face, said inward face being a congruent replica of said section;
- a grated substrate having an outer face in contact and congruent with said inward face, and an inner face defining a succession of narrow, elongated reflective panels wherein said panels are oriented to present a composite but linearly reflective surface to light rays emanating from a point in space located inwardly from said windshield, the inner face of each of said panels being flat, reflective and forming varying angles with the outer face of the substrate.
- 2. The combination claimed in claim 1, wherein each of said panels lies in a plane defined by a first transversal angle with the horizon and by a second longitudinal angle with said inward face, the first and second angles of the successive panels varying from panel to panel across the span of said support to accommodate the slant and radius of said inward face.
- 3. The combination of claim 2, wherein said grated substrate is integral with said inward face.
- 4. The combination of claim 3, wherein said panels are etched into said inward face.
- 5. The combination of claim 2, wherein the width of each of said panels falls between 100 and 500 micrometers.
- 6. The combination of claim 2, wherein said windshield has a generally arcuate shape slanting downwardly and forwardly.
- 7. The combination of claim 2, which further comprises a layer of tinted material over said grated surface.
- 8. The combination of claim 7, wherein said layer comprises means for adjusting the tint of the material.
PRIOR APPLICATIONS
This is a continuation-in-part of Ser. No. 07/553,983 filed Jul. 17, 1990, now U.S. Pat. No. 5,054,900, which is a continuation of Ser. No. 07/380,374 filed Jul. 17, 1989 now abandoned.
The invention relates to panoramic rearview mirrors, and to the design requirements for the fabrication of grated optical surfaces.
The common rearview mirror of an automotive vehicle is composed of a single piece of silvered glass or plexiglass approximately 5.times.25 centimeters in size. It is mounted near the center of the inner top section of the windshield as illustrated in FIG. 1. The plane of the mirror is oriented in a generally vertical position or is slightly tilted downward by a small pitch angle, and is rotated toward the driver. The angle of rotation or yaw angle, as measured from a vector normal to the mirror surface, is approximately 20 degrees with the vehicle axis of travel. The driver's eyes are approximately 60 centimeters from the mirror which yields a viewing angle of 10 to 20 degrees toward the rear of the vehicle.
To expand this viewing angle, a number of approaches have been tried. The simplest approach is for the driver to move his head from side to side to expand the total viewing angle. This yields only a limited increase in coverage and is a slow an tiring process. Outside rear view mirrors may be used to provide additional lateral coverage. This approach produces a variety of different unrelated views separated by blind spots.
A broader, continuous, viewing angle can only be obtained by increasing the size of the mirror. Wider inside mirrors can be used, but are limited to only a few additional centimeters in width and a correspondingly small increased in viewing angle. The confines of a vehicle limit the length of a planar mirror. A long, linear mirror would have to project forward through the windshield and back into the passenger compartment.
The mirror can be segmented into several independent mirror sections aligned along the top inner edge of the windshield to produce a wide angle view. This approach yields a wide field of vision, but requires a relatively large and bulky assembly, and produces confusing discontinuities as the view shifts from one mirror section to the other.
Convex mirrors expand the viewing angle and avoid the discontinuities, but produce substantial distortion of the reflected objects and misleading perception of their distances to the vehicle.
The principal and secondary objects of the invention are to provide a wide angle, distortion-free rearview for an automotive vehicle which can be mounted directly onto or near the surface of the windshield.
This is accomplished by forming a mirror that consists of a large number of extremely narrow elongated mirrors or micro grooves whose reflecting surfaces are all aligned in the same direction as a conventional rearview mirror and whose axes lies on the lines of the local intersection of the mirror and the windshield.
US Referenced Citations (6)
Continuations (1)
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Number |
Date |
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380374 |
Jul 1989 |
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Continuation in Parts (1)
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553983 |
Jul 1990 |
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Patent Grant
5113292
