Chromatic confocal range sensor comprising a camera portion

Patent metadata

Field	Value
Publication number	US-9829312-B2
Application number	US-201514795555-A
Country	US
Kind code	B2
Filing date	Jul 9, 2015
Priority date	Jul 9, 2015
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

A chromatic confocal range sensor optical pen comprises a housing, an in/out optical fiber, a chromatically dispersive lens configuration, a reflected light dividing configuration comprising a lower NA zone and a higher NA zone, and a camera portion. The lens configuration is configured to receive source light from the optical fiber and output focused source light to a workpiece surface with axial chromatic dispersion, and receive reflected light from the workpiece surface and focus at least a portion of the reflected light to the fiber aperture. The reflected light dividing configuration is arranged to divide the reflected light into a measurement portion and an imaging portion. In some embodiments, the lower NA zone directs the imaging portion along an imaging optical path to the image detector, and the higher NA zone directs the measurement portion along a measurement optical path to a point proximate to the fiber aperture.

First claim

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A chromatic confocal range sensor optical pen operable to provide an image of a measurement spot on a workpiece surface to be measured, the chromatic confocal range sensor optical pen comprising:
a housing;
an in/out optical fiber including a fiber aperture configured to output source light along a measurement optical path and receive reflected light along the measurement optical path;
a chromatically dispersive lens configuration having an optical axis which defines a measurement axis of the chromatic confocal range sensor optical pen, the lens configuration configured to:
receive the source light and output focused source light to a workpiece surface with axial chromatic dispersion; and
receive reflected light from the workpiece surface and focus at least a portion of the reflected light comprising reflected source light along the measurement optical path to a point proximate to the fiber aperture;

a reflected light dividing configuration arranged to receive the reflected light from the chromatically dispersive lens configuration, and divide the reflected light into a measurement portion and an imaging portion; and
a camera portion comprising an image detector,
wherein:
the reflected light dividing configuration comprises a lower numerical aperture (NA) zone arranged along the optical axis, and a higher numerical aperture (NA) zone surrounding the lower NA zone; and

the chromatic confocal range sensor optical pen is configured with one of the lower NA zone and the higher NA zone of the reflected light dividing configuration directing the imaging portion of the reflected light along an imaging optical path to the image detector, and the other of the higher NA zone and the lower NA zone of the reflected light dividing configuration directing the measurement portion of the reflected light along the measurement optical path to the point proximate to the fiber aperture.

2. The chromatic confocal range sensor optical pen of claim 1 , wherein one of the lower NA zone and the higher NA zone is a reflective zone and the other is a transmissive zone.

3. The chromatic confocal range sensor optical pen of claim 2 , wherein the chromatic confocal range sensor optical pen is configured with the lower NA zone of the reflected light dividing configuration directing the imaging portion of the reflected light along an imaging optical path to the image detector, and the higher NA zone of the reflected light dividing configuration directing the measurement portion of the reflected light along the measurement optical path to the point proximate to the fiber aperture.

4. The chromatic confocal range sensor optical pen of claim 1 , wherein the imaging optical path is contained in the housing and within a radius of the chromatically dispersive lens configuration in a direction perpendicular to the optical axis of the chromatic confocal range sensor optical pen.

5. The chromatic confocal range sensor optical pen of claim 1 , wherein the reflected light dividing configuration comprises a transmissive substrate, the lower NA zone comprises a masked reflective region of the transmissive substrate and the higher NA zone comprises an unmasked region of the transmissive substrate.

6. The chromatic confocal range sensor optical pen of claim 1 , wherein the reflected light dividing configuration is located between the chromatically dispersive lens configuration and the in/out optical fiber.

7. The chromatic confocal range sensor optical pen of claim 1 , wherein the reflected light dividing configuration comprises a metallic substrate, the lower NA zone comprises a region suspended within the metallic substrate and the higher NA portion comprises holes through the metallic substrate.

8. The chromatic confocal range sensor optical pen of claim 1 , wherein the camera portion comprises a wavelength filter.

9. The chromatic confocal range sensor optical pen of claim 1 , wherein the camera portion comprises a field lens proximate to the imaging portion.

10. The chromatic confocal range sensor optical pen of claim 1 , wherein the chromatic confocal range sensor optical pen is configured with the lower NA zone of the reflected light dividing configuration directing the imaging portion of the reflected light along an imaging optical path to the image detector, and the higher NA zone of the reflected light dividing configuration directing the measurement portion of the reflected light along the measurement optical path to the point proximate to the fiber aperture.

11. The chromatic confocal range sensor optical pen of claim 10 , wherein the lower NA zone comprises a focusing portion.

12. The chromatic confocal range sensor optical pen of claim 1 , wherein the chromatic confocal range sensor optical pen is configured with the higher NA zone of the reflected light dividing configuration directing the imaging portion of the reflected light along an imaging optical path to the image detector, and the lower NA zone of the reflected light dividing configuration directing the measurement portion of the reflected light along the measurement optical path to the point proximate to the fiber aperture.

Assignees

• Mitutoyo Corp
• Mituloyo Corp

Inventors

• Xie Yong

Classifications

• H04N23/55

  Optical parts specially adapted for electronic image sensors; Mounting thereof · CPC title

• H04N23/56

  provided with illuminating means · CPC title

• G01B11/0608 Primary

  Height gauges · CPC title

• G01B2210/50

  Using chromatic effects to achieve wavelength-dependent depth resolution · CPC title

• G01B11/026 Primary

  by measuring distance between sensor and object (G01B11/0608 takes precedence) · CPC title