Optical: systems and elements – Lens – Reverse telephoto
Reexamination Certificate
2001-01-23
2003-07-08
Robinson, Mark A. (Department: 2872)
Optical: systems and elements
Lens
Reverse telephoto
C359S565000, C348S118000
Reexamination Certificate
active
06590719
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates generally to vision systems, particularly for vehicles which provide a vehicle operator with wide angle scenic information of an area immediately around the vehicle. While the invention is illustrated in a rear-view vision system, it may be applied to other viewing directions, as well as to non-vehicular applications.
A long felt need in the art of vehicle vision systems, such as rear-view systems, has been to provide an operator of a vehicle with wide angle scenic information of an area around the vehicle, such as directly rearward of the vehicle, when the vehicle is traveling in reverse. Neither interior rear-view mirrors nor side exterior mirrors allow for visibility of the area immediately rearward of the vehicle's bumper, which is the information most critical to the vehicle operator when backing up. Therefore, various camera-based rear view vision systems have been proposed to provide visibility of this blind spot.
Various camera-based rear vision systems for vehicles backing up have been proposed. In one form of these systems, a camera with a conventional, standard lens is located on the rearward portion of the vehicle to provide a view of the area behind the vehicle. However, standard lenses fail to capture a wide angle view of the area, thus failing to provide the vehicle operator with an image of the entire critical area directly rearward of the vehicle.
In order to provide a wider angle view of the rearward area, a wide angle lens system may be used with the camera to capture the critical area. However, because the wide angle lens elements are typically precision optics, not only is the initial cost to manufacture and implement them very high, but so is the cost to replace them, should they be damaged or broken on the vehicle in the vulnerable area in which they are typically located.
Another difficulty with the proposed multi-element glass lens and camera systems is that they are difficult to package within the small area available at the rearward portion of the vehicle. These systems may comprise ten or more precision optic lens elements and are thus assembled as a long, horizontally oriented cylindrical column, which is then positioned within the trunk lid or a rear panel of the vehicle. This results in the camera system protruding substantially forwardly into the trunk space. Generally, it is desirable to minimize intrusion into the trunk space, such that the overall trunk space is maximized. This is desirable not only because trunk space is considered valuable to consumers, but also because consumers tend to over-pack their trunk spaces, and then force the trunk lid closed, which may result in damage to any components trapped between the packed items and the trunk lid. This is an even greater concern with the proposed multi-element glass lens systems, since the many optic elements may be fragile and thus prone to breaking. In a van, pick-up truck or the like, the long, cylindrical column of these camera systems would extend forward into an open space, and be more prone to damage.
SUMMARY OF THE INVENTION
The present invention is directed toward enhancing exterior visibility to the driver of a vehicle by providing an imaging system, which provides a wide angle field of view of the area directly exteriorly of a vehicle, that is compact, durable and inexpensive to manufacture. The imaging system of the present invention is capable of being compactly packaged within a portion of the vehicle and requires a minimal number of elements in order to minimize the size, cost and weight of the system.
According to an aspect of the present invention, a vehicular vision system provides scenic information of an area around of a vehicle. The vision system comprises a focusing lens having a receiving end and a focusing end, a wide angle lens positioned at the receiving end of the focusing lens and an image capture device which is adapted to receive an image refracted through the focusing lens group. The wide angle lens includes an outer negative optic and an inner negative optic positioned between the outer negative optic and the receiving end of the focusing lens. The wide angle lens further includes a diffractive element. The wide angle lens directs a virtual image of a wide angle field of view of a scene exteriorly of the vehicle toward the receiving end of the focusing lens. The virtual image of the wide angle field of view is focused by the focusing lens onto the image capture device.
In one form, the wide angle lens elements are formed from one of polycarbonate, acrylic and crown glass materials. The focusing lens preferably also comprises optic elements formed from one of polycarbonate and acrylic materials.
According to another aspect of the present invention, a vehicular vision system for providing scenic information of an area exteriorly of a vehicle comprises a focusing lens, a wide angle lens, an image capture device and a display system. The focusing lens includes a first focusing optic, a middle focusing optic and a third focusing optic, wherein the middle focusing optic is positioned along an optic path between the first and third focusing optics. The wide angle lens directs a virtual image of a wide angle field view of a scene exteriorly of the vehicle toward the focusing lens. The wide angle lens has an outer wide angle optic and an inner wide angle optic, where the outer wide angle optic is positioned toward an exterior of the vehicle and the inner wide angle optic is positioned along the optic path between the outer wide angle optic and the focusing lens. The image capture device is adapted to receive an image refracted through the focusing lens, such that the virtual image of the wide angle field of view is focused by the focusing lens onto the image capture device. The display system then displays an image in response to an output of the image capture device. Preferably, the focusing lens comprises one of polycarbonate and acrylic, while the wide angle lens comprises at least one of polycarbonate, acrylic and crown glass.
Therefore, the present invention includes a minimal number of optic elements and may be packaged within the small space constraints of the trunk of a vehicle. The invention is much less costly to manufacture over conventional systems due to the number of plastic components, such as polycarbonate and/or acrylic components. In this manner, the present invention provides a low cost and compact system which produces a maximum field of view to the vehicle operator.
These and other objects, advantages, purposes, and features of this invention will become apparent upon review of the following specification in conjunction with drawings.
REFERENCES:
patent: 5737125 (1998-04-01), Ohashi
patent: 5982544 (1999-11-01), Ogata
Amari Alessandro V.
Donnelly Corporation
Robinson Mark A.
Van Dyke Gardner, Linn & Burkhart, LLP
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