Optical system and method

• US 8,970,934 B2
• Filed: 06/20/2013
• Issued: 03/03/2015
• Est. Priority Date: 09/28/2012
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: General Electric Company
• Inventors: Yang, Dongmin
• Primary Examiner(s): TRA, TUYEN Q
• Application Number:
  US13/922,513
• Publication Number:
  US 20130278747A1
• Time in Patent Office: 621 Days
• Field of Search: 359/240, 359/242, 359/256, 359/489.06
• US Class Current: 359/240
• CPC Class Codes: G02B 15/00 Optical objectives with means for varying the magnification anamorphotic objectives G02B13/08
• CPC Class Codes: G02B 23/2438 Zoom objectives
• CPC Class Codes: G02B 23/2446 of the image relay G02B23/26 takes precedence
• CPC Class Codes: G02B 23/2476 Non-optical details, e.g. housings, mountings, supports
• CPC Class Codes: G02B 27/286 for controlling or changing the state of polarisation, e.g. transforming one polarisation state into another G02B5/3083 takes precedence; light guide coupling means utilising polarising elements G02B6/34
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: H04N 7/183 for receiving images from a single remote source

Abstract

An optical system in a video probe assembly includes a plurality of lenses configured to refract separate linearly polarized rays under different refractive indexes to form a plurality of different focal lengths. The optical system includes at least one light modulating element that modulates a polarization state of the linearly polarized rays passing through the at least one light modulating element in response to a control signal. The optical system includes a polarizer element that filters out some of the modulated linearly polarized rays passing through the polarizer element. A method of inspecting a target with an optical system of a video probe assembly is also provided.

Claims

1. An optical system in a video probe assembly, the optical system including:

a plurality of lenses, each having at least one curved surface, configured to refract separate decomposed linearly polarized rays under different refractive indexes to form a plurality of different focal lengths;

a plurality of light modulating elements each configured to modulate a polarization state of the linearly polarized rays proceeding from at least one of the plurality of lenses and passing through the respective light modulating elements in response to a control signal; and

a polarizer element configured to filter out some of the linearly polarized rays proceeding from at least one of the plurality of light modulating elements and passing through the polarizer element; and

an imager located adjacent to the polarizer element to receive polarized rays proceeding from the polarizer element.

2. The optical system of claim 1, wherein the lenses each include birefringent elements.

3. The optical system of claim 1, wherein the plurality of light modulating elements include a first light modulating element and a second light modulating element.

4. The optical system of claim 3, wherein the plurality of lenses includes a first lens and a second lens.

5. The optical system of claim 4, wherein the first light modulating element is positioned between the first lens and the second lens.

6. The optical system of claim 5, wherein the second light modulating element is positioned between the second lens and the polarizer element.

7. The optical system of claim 1, wherein the linearly polarized rays passing through the plurality of lenses are configured to produce at least four different focal lengths.

8. The optical system of claim 1, wherein the polarizer element is rotatable.

9. The optical system of claim 8, wherein the rotation of the polarizer element is configured to filter out at least some of the linearly polarized rays.

10. The optical system of claim 1, wherein the linearly polarized rays include ordinary ray light and extra-ordinary ray light.

11. An optical system in a video probe assembly, the optical system including:

a plurality of lenses, each having at least one curved surface, configured to refract separate linearly polarized rays under different refractive indexes to form a plurality of different focal lengths;

at least one light modulating element configured to modulate a polarization state of the linearly polarized rays passing through the at least one light modulating element in response to a control signal; and

a rotatable polarizer element configured to filter out some of the linearly polarized rays passing through the polarizer element; and

an imager located adjacent to the polarizer element to receive polarized rays proceeding from the polarizer element.

12. The optical system of claim 11, wherein the lenses each include birefringent elements.

13. The optical system of claim 12, wherein the at least one light modulating element includes a first light modulating element and a second light modulating element.

14. The optical system of claim 13, wherein the plurality of lenses includes a first lens and a second lens.

15. The optical system of claim 14, wherein the first light modulating element is positioned between the first lens and the second lens.

16. The optical system of claim 15, wherein the second light modulating element is positioned between the second lens and the polarizer element.

17. The optical system of claim 16, wherein the linearly polarized rays passing through the plurality of lenses are configured to produce at least four different focal lengths.

18. The optical system of claim 11, wherein the rotation of the polarizer element is configured to filter out at least some of the linearly polarized rays.

19. A method of inspecting a target with an optical system of a video probe assembly, the method including:

providing a plurality of lenses, each having at least one curved surface, for refracting separate decomposed linearly polarized rays under different refractive indexes to form a plurality of different focal lengths;

directing the linearly polarized rays through at least one light modulating element; and

focusing the linearly polarized rays proceeding from a polarizer element onto an imager.

20. The method of claim 19, further including the steps of:

refracting one of the linearly polarized rays by a first refractive index;

refracting another of the linearly polarized ray by a second refractive index; and

modulating a polarization state of the linearly polarized rays.