ILLUMINATION APPARATUS AND MEASUREMENT APPARATUS

• US 20180073863A1
• Filed: 11/15/2017
• Published: 03/15/2018
• Est. Priority Date: 05/29/2015
• Status: Active Grant

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: WATANABE, Daichi
• Granted Patent: US 10,156,436 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 1/00 Instruments for performing medical examinations of the interior of cavities or tubes of the body by visual or photographical inspection, e.g. endoscopes examination of body cavities or body tracts using ultrasonic, sonic or infrasonic waves A61B8/12; endoscopic instruments for taking cell samples or for biopsy A61B10/04; for surgical purposes A61B17/00; endoscopic surgical cutting instruments A61B17/32; surgical instruments using a laser beam being directed along or through a flexible conduit A61B18/22; Illuminating arrangements therefor for the eyes A61B3/00
• CPC Class Codes: A61B 1/0605 for spatially modulated illumination
• CPC Class Codes: A61B 1/0661 Endoscope light sources
• CPC Class Codes: A61B 1/07 using light-conductive means, e.g. optical fibres
• CPC Class Codes: G01B 11/24 for measuring contours or curvatures
• CPC Class Codes: G01B 11/2441 using interferometry
• CPC Class Codes: G01B 11/25 by projecting a pattern, e.g. one or more lines, moiré fringes on the object G01B11/255 takes precedence ; image analysis for depth or shape recovery G06T7/50
• CPC Class Codes: G01B 11/30 for measuring roughness or irregularity of surfaces
• CPC Class Codes: G02B 23/2461 Illumination
• CPC Class Codes: G02B 23/2469 using optical fibres
• CPC Class Codes: G02B 27/283 used for beam splitting or combining
• 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

Abstract

An illumination apparatus includes a light source including a semiconductor laser that emits coherent light, a polarization splitter including rutile, a half-phase retardation film, and another rutile to split optical paths by the polarization direction of incident light, and a projection polarization switching mechanism including a half-wave plate unit, a quarter-wave plate unit, and a polarizing film to switch projected light emitted from the polarization splitter between polarization components of light transmitted over optical paths split by the polarization splitter and a polarization component of light transmitted over any one optical path. As a result, a compact illumination apparatus, and a measurement apparatus using the same, with a common light source and optical system for both observation light and measurement light can be provided.

Claims

1. An illumination apparatus comprising:

a light source configured to emit coherent light;

a polarization splitter configured to split an optical path of incident light by polarization direction; and

a projection polarization switching mechanism configured to switch projected light emitted from the polarization splitter between polarization components of light transmitted over optical paths split by the polarization splitter and a polarization component of light transmitted over any one optical path.

2. The illumination apparatus of claim 1, wherein the projection polarization switching mechanism comprises:

a polarization adjuster disposed between the light source and the polarization splitter and configured to adjustably change a polarization state of the light emitted from the light source; and

a polarizer disposed in a later stage than the polarization splitter and configured to transmit only linearly polarized light in a particular direction.

3. The illumination apparatus of claim 2, wherein the polarization adjuster comprises:

a half-wave plate; and

a half-wave plate rotator configured to adjust a direction of an optical axis of the half-wave plate by rotating the half-wave plate.

4. The illumination apparatus of claim 3, wherein the polarization adjuster further comprises:

a quarter-wave plate on the polarization splitter side of the half-wave plate; and

a quarter-wave plate rotator configured to adjust a direction of an optical axis of the quarter-wave plate by rotating the quarter-wave plate.

5. The illumination apparatus of claim 3, wherein the polarization adjuster comprises a phase adjuster disposed on the light source side of the half-wave plate and configured to control a phase difference between beams of polarized light whose optical paths are split by the polarization splitter.

6. The illumination apparatus of claim 1, wherein the projection polarization switching mechanism comprises:

a polarization adjuster disposed between the light source and the polarization splitter and configured to change a polarization state of the light emitted from the light source; and

a polarizer disposed in a later stage than the polarization splitter and configured to adjust a direction of a transmission axis.

7. The illumination apparatus of claim 6, wherein the polarization adjuster comprises:

a half-wave plate; and

a half-wave plate rotator configured to adjust a direction of an optical axis of the half-wave plate by rotating the half-wave plate; and

a quarter-wave plate on the polarization splitter side of the half-wave plate.

8. The illumination apparatus of claim 1, further comprising a polarization-maintaining waveguide disposed between the light source and the polarization splitter so that polarization-maintaining directions of the polarization-maintaining waveguide are equivalent to polarization directions spilt by the polarization splitter.

9. A measurement apparatus comprising:

the illumination apparatus of claim 1;

an imager configured to capture an image of an object, an interference fringe being projected on the object by the illumination apparatus; and

a calculator configured to derive a shape of the object using the interference fringe in the image of the object captured by the imager and a positional relationship between the illumination apparatus and the imager.