Stereoscopic optical system, and optical apparatus for stereoscopic measurement, stereoscopic measurement apparatus and stereoscopic observation apparatus each using the same

1. A stereoscopic optical system comprising, at a distal end of an insertion part of an endoscope:

a two-path forming optical system for forming two paths of rays involving a parallax;

an image forming optical system for forming images out of light travelling along the respective paths of rays in the two-path forming optical system onto a common region; and

an image sensor arranged at an image forming position of the image forming optical system;

wherein the stereoscopic optical system is provided with a time-division path switching means that is capable of switching between the two paths of rays in a time-division manner so that only light coming from either one of the two paths of rays formed by the two-path forming optical system enters the image forming optical system;

wherein the time-division path switching means comprises a diaphragm member having two apertures arranged to be mated with the two paths of rays formed by the two-path forming optical system, and a blocking member that is capable of blocking the two apertures of the diaphragm member alternately in a time-division manner; and

wherein the blocking member includes a blocking plate that is formed to have a size configured to block one of the two apertures of the diaphragm member, and a lever that is connected with the blocking plate at one end and mounted rotatably around a pivot on the diaphragm member at another end, and is configured to cause the blocking plate to block the two apertures alternately by rotating the lever around the pivot.

2. The stereoscopic optical system according to claim 1 , wherein the diaphragm member is constructed of a variable diaphragm.

3. The stereoscopic optical system according to claim 1 , wherein the two-path forming optical system is constructed of a pair of afocal optical systems.

4. The stereoscopic optical system according to claim 1 , wherein the two-path forming optical system is mountably and dismountably arranged.

5. The stereoscopic optical system according to claim 3 , wherein an interpath distance converting means for adjusting a distance between the two paths of rays involving a parallax is arranged on an object side of the time-division path switching means.

6. The stereoscopic optical system according to claim 5 , wherein the interpath distance converting means is constructed of an axially symmetric wedge prism arranged between the pair of afocal optical systems and the time-division path switching means, and wherein the pair of afocal optical systems are arranged at positions to be mated with the two paths of rays as widened via the axially symmetric wedge prism.

7. The stereoscopic optical system according to claim 5 , wherein the pair of afocal optical systems are decentered as being symmetric with respect to an optical axis of the image forming optical system, and wherein the interpath distance converting means is constructed of the pair of afocal optical system decentered as being symmetric with respect to the optical axis of the image forming optical system.

8. The stereoscopic optical system according to claim 1 , wherein the two-path forming optical system has a variable focus lens.

9. The stereoscopic optical system according to claim 1 , wherein the two-path forming optical system is constructed of the time-division path switching means.

10. An optical apparatus for stereoscopic measurement, comprising the stereoscopic optical system according to claim 1 .

11. A stereoscopic measurement apparatus comprising:

the stereoscopic optical system according to claim 1 ;

a measurement value calculating processing section for calculating, using images of a measurement object, which have been captured in the time-division manner through the respective paths of rays via the image sensor of the stereoscopic optical system, a displacement between corresponding measurement points on the respective images by performing a correlation operation and calculating a predetermined measurement value on the measurement object using the displacement as calculated; and

a measurement value display means for displaying the measurement value calculated by the measurement value calculating processing section.

12. The stereoscopic measurement apparatus according to claim 11 , further comprising:

an image processing section for performing a predetermined process on the images of the measurement object captured via the image sensor of the stereoscopic optical system; and

an image display means for displaying the image of the measurement object as image-processed via the image processing section.

13. The stereoscopic measurement apparatus according to claim 12 , further comprising:

a path switching action ordering means for ordering a path switching action by the time-division path switching means; and

a path switching action control section for controlling the path switching action by the time-division path switching means on a basis of an order from the path switching action ordering means;

wherein the path switching action ordering means is configured to be capable of issuing an order upon selecting either one of a first order mode for performing alternate switching between the paths of rays by the time-division path switching means and a second order mode for performing switching into either one of the paths of rays by the time-division path switching means.

14. A stereoscopic observation apparatus, comprising the stereoscopic optical system according to claim 1 .

15. The stereoscopic observation apparatus according to claim 14 , further comprising:

an image processing section for performing a predetermined process on images of an observation object captured via the image sensor of the stereoscopic optical system; and

an image display means for displaying a processed image.