Wide-angle objective lens system and camera

• US 7,995,281 B2
• Filed: 12/09/2009
• Issued: 08/09/2011
• Est. Priority Date: 08/10/2006
• Status: Expired due to Fees

• Current Assignee: Mekra Lang GmbH & Company KG
• Original Assignee: Mekra Lang GmbH & Company KG
• Inventors: Reinhard, Thomas, Eckerl, Klaus, Witzke, Michael, Lang, Werner
• Primary Examiner(s): Harrington; Alicia M
• Application Number:
  US12/653,214
• Publication Number:
  US 20100091379A1
• Time in Patent Office: 608 Days
• Field of Search: 359/649, 359/714, 359/725, 359/740, 359/753
• US Class Current: 359/649
• CPC Class Codes: G02B 13/0045 having five or more lenses
• CPC Class Codes: G02B 13/04 Reversed telephoto objectives

Abstract

A vehicle camera and wide-angle objective lens system are disclosed wherein the wide-angle objective lens has image aberrations or errors that do not deteriorate the detection of obstructions or obstacles in its field of view.

Claims

1. A wide-angle objective lens system, comprising:

a first lens group including a first lens, a second lens, and a third lens;

an entrance aperture through which light from an object is gathered over a diagonal field angle α

of 118°

±

10°

;

an optical iris arranged behind the first lens group; and

a second lens group including a fourth lens and a fifth lens, wherein the second lens group is arranged behind the optical iris, wherein the fourth lens is an aspheric lens, and wherein a lens of the second lens group corrects image distortion.

2. The system of claim 1, wherein the system includes a maximum number of five lenses.

3. The system of claim 1, further comprising:

a transparent protective plate disposed in front of the entrance aperture.

4. The system of claim 3, wherein the transparent protective plate is a parallel surfaced plate.

5. The system of claim 1, wherein the aspheric lens is a biaspheric lens.

6. The system of claim 1, wherein the aspheric lens has a concave-convex curvature.

7. The system of claim 1, wherein the system has an optical constructed length (OBL) of 18.0 mm±

5 mm.

8. The system of claim 7, wherein the optical iris is located at 60% ±

10% of the optical construction length (OBL) relative to the entrance aperture.

9. The system of claim 1, wherein the optical iris has a diameter of 1.26 mm±

0.5 mm.

10. The system of claim 1, wherein the fourth lens and the fifth lens are in direct contiguous contact with one another without a spacer element there between.

11. The system of claim 1, wherein the second lens group projects light from the first lens group that has passed through the optical iris onto an image surface with an image distortion of less than 5%.

12. A wide-angle objective lens system, comprising:

a first lens group including a first lens, a second lens, and a third lens;

an entrance aperture that gathers light from an object over a diagonal field angle α

of 142°

±

10°

;

an optical iris arranged behind the first lens group; and

a second lens group including a fourth lens and a fifth lens, wherein the second lens group is arranged behind the optical iris, wherein the fourth lens is a biaspheric lens, and wherein a lens of the second lens group corrects image distortion.

13. The system of claim 12, wherein the system includes a maximum number of five lenses.

14. The system of claim 12, further comprising:

a transparent protective plate disposed in front of the entrance aperture.

15. The system of claim 14, wherein the transparent protective plate is a parallel surfaced plate.

16. The system of claim 12, wherein the system has an optical constructed length (OBL) of 21.4 mm±

5 mm, and wherein the optical iris is located at 75%±

10% of the optical construction length (OBL) relative to the entrance aperture.

17. The system of claim 12, wherein the fourth lens and the fifth lens are in direct contiguous contact with one another without a spacer element there between.

18. A wide-angle camera for supervision of the immediate environment of motor vehicles, comprising:

a first lens group including a first lens, a second lens, and a third lens;

an entrance aperture that gathers light from an object;

an optical iris arranged behind the first lens group;

an image surface; and

a second lens group including a fourth lens and a fifth lens, wherein the second lens group is arranged behind the optical iris, wherein the second lens group projects light from the first lens group that has passed through the optical iris onto the image surface, wherein the second lens group includes an aspheric lens that corrects image distortion, and wherein a lens of the second lens group corrects aberrational swelling and curvature of the image.

19. The camera of claim 18, wherein the entrance aperture gathers light from an object over a diagonal field angle a of 142°

±

10°

, and wherein light impinging upon the image surface has an image distortion of less than 17%.

20. The camera of claim 18, wherein the entrance aperture gathers light from an object over a diagonal field angle a of 118°

±

10°

, and wherein light impinging upon the image surface has an image distortion of less than 5%.

21. The camera of claim 18, further comprising:

a transparent protective plane plate disposed in front of the first lens group.

22. The camera of claim 18, further comprising:

an infrared filter located in front of the image capture unit.