VIEW EXPANDING AND DIRECTING OPTICAL SYSTEM

• US 3,809,461 A
• Filed: 05/12/1972
• Issued: 05/07/1974
• Est. Priority Date: 05/12/1972
• Status: Expired due to Term

• Current Assignee: Donnelly Corporation (Magna International Incorporated)
• Original Assignee: Dorothy J. Ebeling, John D. Baumgardner
• Inventors: Baumgardner, John D., Ebeling, Dorothy J.
• Primary Examiner(s): Wibert, Ronald L.
• Assistant Examiner(s): Tokar, Michael J.
• Application Number:
  US05/252,611
• Time in Patent Office: 725 Days
• Field of Search: 350/103,211,286,287
• US Class Current: 359/737
• CPC Class Codes: B60R 1/001 integrated in the windows, e.g. Fresnel lenses
• CPC Class Codes: B60R 1/002 specially adapted for covering the peripheral part of the vehicle, e.g. for viewing tyres, bumpers or the like integrated in the windows B60R1/001; combined with rear-view mirrors B60R1/08
• CPC Class Codes: B60R 1/10 Front-view mirror arrangements; specially adapted for covering the peripheral part of the vehicle B60R1/002; Periscope arrangements , i.e. optical devices using combinations of mirrors, lenses, prisms or the like specially adapted for covering the peripheral part of the vehicle B60R1/002; for viewing traffic-lights B60R1/005; Other mirror arrangements giving a view from above or under the vehicle
• CPC Class Codes: G02B 2027/0154 with movable elements
• CPC Class Codes: G02B 2027/0169 Supporting or connecting means other than the external walls
• CPC Class Codes: G02B 23/00 Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 27/0149 characterised by mechanical features G02B27/0176 takes precedence

Abstract

A view expanding and directing optical system for use in viewing around obstacles and the like comprising in combination a negative Fresnel lens and a Fresnel prism disposed in separate planes immediately adjacent one another. In the preferred embodiment, the system is mounted on a vehicle, at the rear thereof, whereby the system provides an expanded and demagnified viewing area to the rear of and below the level of the rear window and/or laterally of the vehicle. In other embodiments, the system may be coupled to means for extending or retracting it at desired times, and may be used in conjunction with vision aiding elements, such as a rearview periscope, for providing an expanded and demagnified viewing area laterally and to the rear of the vehicle.

Claims

1. A view expanding and directing optical unit comprising the combination of optical elements including a Fresnel lens having a negative focal length and a Fresnel prism, said lens and prism located adjacent one another and arranged to intersect a desired line of sight to provide to a person viewing along said line of sight an expanded field of view in which the objects in said field of view are demagnified;

said optical elements each including a grooved and a generally flat side;

the generally flat side of one of said otpical elements facing away from said other optical element.

2. An optical unit as described in claim 1 wherein said generally flat sides of both said optical elements face away from each other respective optical element.

3. An optical system for expanding a field of view and for viewing around obstacles and the like comprising in combination:

a Fresnel lens having a negatIve focal length and a prism having a specified angle of deviation of incident light rays;

adjacent said lens and prism positioned adjacent one another whereby the viewing area visible through said system is expanded and are the objects in said viewing area. demagnified said Fresnel lens including lens sections having aspherical surfaces.

4. An optical system as described in claim 3 wherein said prism is a Fresnel prism having a specified angle of deviation of incident light rays.

5. An optical system as described in claim 4 wherein said Fresnel lens is a rotationally optically symmetrical Fresnel lens, said rotational optical symmetry being defined with respect to a central rotational axis perpendicular to said plane including said lens, said axis passing through the opitcal center of said lens.

6. An optical system as described in claim 3 wherein said Fresnel lens is an off-axis Fresnel lens section having a predetermined degree of optical asymmetry determining the expansion, demagnification and position of the viewing area of said lens.

7. An optical system as described in claim 4 wherein said lens and prism each include a relatively flat side and a grooved side, said lens and prism being disposed generally parallel to one another such that said flat sides face outwardly and said grooved sides face inwardly.

8. An optical system as described in claim 4 wherein said lens and prism are mounted adjacent and generally parallel one another in a means for adjusting the position of said system whereby the position of said expanded and demagnified viewing area with respect to an obstacle to be viewed around its selectively adjustable.

9. An optical system as described in claim 8 wherein said means for adjusting the position of said system comprises a support means including a frame, securing means, and a base;

said lens and prism being mounted in said frame, said frame being pivotally mounted on said base by means of said securing means with its pivot axis being parallel to said planes containing said lens and said prism such that said frame may be selectively adjustable.