System and method to illuminate and image the inside diameter of a stent

Abstract

An optical system is effective to illuminate and scan an interior wall of an object having an interior bore, such as a stent. The system includes a light source, an object support having a light conducting portion, an image taking lens, and a line scan camera. The interior bore and the light conducting portion of the object support are in axial alignment with a center optical axis of the image taking lens. A drive mechanism engages the object without impacting the axial alignment. Various aspect of this optical system include a rotating wheel or transparent plate as the drive mechanism. The object support may be an opaque rod having a light conducting portion or a transparent rod. Electronics associated with this optical system include a rotary encoder engaging the drive system to drive an electric circuit capable of triggering the line scan camera in response to rotation of the object, thereby building a line by line image of the interior bore and the line scan camera connected to a computer-based imaging system effective to identify cosmetic and functional manufacturing defects.

Description

DESCRIPTION OF DRAWINGS

FIG. 1 schematically illustrates illumination of an inner sidewall of a stent in accordance with an embodiment of the invention.

FIG. 2 shows a beamsplitter mounted inside a slotted rod to provide more complete illumination of the inner sidewall of the stent.

FIG. 3 shows an alternative embodiment utilizing a flat stage to drive the stent around slotted rod.

FIG. 4 shows another alternative utilizing two pairs of drive rollers that move a transparent stage while capturing and rotating the stent.

FIG. 5 shows another embodiment that utilizes three drive rollers to capture and rotate the stent.

FIG. 6 shows another embodiment for rotating a stent.

Claims

1. An optical system effective to illuminate and scan an interior wall of an object having an interior bore; comprising: a light source;an object support having a light conducting portion;an image taking lens;a line scan camera, wherein said interior bore and said light conducting portion are in axial alignment with a center optical axis of said image taking lens; anda drive mechanism engaging said object without impacting said axial alignment with a rotary encoder engaging said drive system and driving an electric circuit capable of triggering said line scan camera in response to rotation of the object, thereby building a line by line image of said interior bore.

2. The optical system of claim 1 wherein said object is disposed between said light source and said image taking lens and said image taking lens is disposed between said object and said line scan camera.

3. The optical system of claim 2 wherein said image taking lens has a depth of focus sufficiently shallow that an exterior wall of said object is out of focus when an opposing interior wall of object is in focus.

4. The optical system of claim 3 wherein said image taking lens has a numerical aperture of at least 0.1.

5. The optical system of claim 3 wherein said object support is an opaque rod and said light conducting portion is a first slot extending therethrough.

6. The optical system of claim 5 wherein said first slot has inwardly directed sidewalls effective to receive and reflect light from said light source.

7. The optical system of claim 5 wherein a beam splitter effective to reflect light from said light source to said interior wall is disposed within said first slot.

8. The optical system of claim 7 wherein a second slot disposed generally perpendicularly to said first slot is effective to provide additional light to said beam splitter for reflection to said interior wall.

9. The optical system of claim 3 wherein said drive system is a rotating wheel that contacts said object.

10. The optical system of claim 9 wherein said rotating wheel includes a light conducting through hole in axial alignment with said interior bore.

11. The optical system of claim 9 wherein said rotating wheel has a diameter greater than the diameter of said object.

12. The optical system of claim 3 wherein said drive system is a light conducting plate capable of linear motion.

13. The optical system of claim 1 wherein said image taking lens is disposed between said object and said line scan camera.

14. The optical system of claim 13 wherein said image taking lens has a depth of focus sufficiently shallow that an exterior wall of said object is out of focus when an opposing interior wall of object is in focus.

15. The optical system of claim 14 wherein said drive mechanism includes a light conducting plate disposed between said light source and said object.

16. The optical system of claim 15 wherein said object is compressively restrained between at least two second rollers and said light conducting plate.

17. The optical system of claim 14 wherein said object is compressively restrained between at least three rollers.

18. The optical system of claim 17 wherein surfaces of one or more of said at least three rollers are light reflective.

19. The optical system of claim 1 wherein said entire object support is light conducting.

20. The optical system of claim 19 wherein said object support is a light conducting rod.

21. The optical system of claim 20 wherein a cylindrical lens element is disposed between said object and said image taking lens to compensate for optical distortion.

22. The optical system of claim 1 wherein said line scan camera is connected to a computer-based imaging system effective to identify cosmetic and functional manufacturing defects.

23. The optical system of claim 1 wherein said object is a stent.

24. A method to illuminate an inner bore of an object, comprising: providing a light source, an object support having a light conducting portion, an image taking lens, a line scan camera and a drive mechanism;axially aligning said interior bore and said light conducting portion with a center optical axis of said image taking lens;illuminating a first portion of said inner bore; androtating said object with said drive mechanism without impacting said axial alignment thereby illuminating a second portion of said inner bore with a rotary encoder engaging said drive system and driving an electric circuit capable of triggering said line scan camera in response to rotation of the object, thereby building a line by line image of said interior bore.

25. The method of claim 24 wherein said object is selected to be a stent.