OPTICAL FIBER ENDFACE INSPECTION MICROSCOPE HAVING A SWAPPABLE OPTICAL HEAD

Abstract

There is provided an optical-fiber connector endface inspection microscope system for inspecting an endface of an optical-fiber connector. It comprises one or more image detector for capturing at least one image of the endface to be inspected; an objective lens system comprising a focusing lens for adjusting a focus of the objective lens system on the image detector and a fixed relay lens; a main housing structure enclosing the image detector and the focusing lens; and at least one interchangeable optical head releasably connectable to the main housing structure and enclosing the fixed relay lens, wherein the optical head is releasably connectable to an adapter tip for interfacing with the optical-fiber connector to be inspected.

Claims

1. An optical-fiber connector endface inspection microscope system for inspecting an endface of an optical-fiber connector, the optical-fiber connector endface inspection microscope system comprising: one or more image detector for capturing at least one image of the endface to be inspected; an objective lens system comprising a focusing lens for adjusting a focus of the objective lens system on the image detector and a fixed relay lens; a main housing structure enclosing the image detector and the focusing lens; and at least one interchangeable optical head releasably connectable to the main housing structure and enclosing the fixed relay lens, wherein the optical head is releasably connectable to an adapter tip for interfacing with the optical-fiber connector to be inspected.

2. The optical-fiber connector endface inspection microscope system as claimed in claim 1, wherein the at least one interchangeable optical head comprises a multi-fiber optical head and a single-fiber optical head, mutually interchangeable; wherein the mufti-fiber optical head is releasably connectable to a multi-fiber adapter tip configured to interface with multi-fiber optical-fiber connectors and wherein the single-fiber optical head is releasably connectable to a single-fiber adapter tip configured to interface with single-fiber optical-fiber connectors.

3. The optical-fiber connector endface inspection microscope system as claimed in claim 2, further comprising: at least one multi-fiber adapter tip releasably connectable to the multi-fiber optical head and comprising a multi-fiber optical-fiber connector interface for mechanically engaging with a multi-fiber optical-fiber connector to be inspected; and at least one single-fiber adapter tip releasably connectable to the single-fiber optical head and comprising a single-fiber optical-fiber connector interface for mechanically engaging with a single-fiber optical-fiber connector to be inspected.

4. The optical-fiber connector endface inspection microscope system as claimed in claim 2, wherein the relay lens of the multi-fiber optical head and the relay lens of the single-fiber optical head have mutually different dimensions.

5. The optical-fiber connector endface inspection microscope system as claimed in claim wherein the objective lens system is configured to form a telecentric objective and comprises a telecentric aperture stop.

6. The optical-fiber connector endface inspection microscope system as claimed in claim 5, wherein the aperture stop is positioned at or near the focal point of the objective lens system.

7. The optical-fiber connector endface inspection microscope system as claimed in claim 6, wherein the aperture stop and the focusing lens are together mounted in a lens holder and wherein a distance between the aperture stop and the focusing lens remains fixed during focus.

8. The optical-fiber connector endface inspection microscope system as claimed in claim 7, wherein focus is being adjusted by displacing the lens holder, thereby moving the focusing lens and the aperture stop; the relay lens of the objective lens system remaining fixed within the inspection microscope system during focus adjustment

9. The optical-fiber connector endface inspection microscope system as claimed in claim 8, wherein the objective lens system further comprises a fixed lens enclosed within the main housing structure and wherein during focus adjustment, the fixed lens remains fixed within the inspection microscope system.

10. The optical-fiber connector endface inspection microscope system as claimed in claim 1, wherein the at least one interchangeable optical head comprises an angled optical head and a linear optical head, mutually interchangeable.

11. The optical-fiber connector endface inspection microscope system as claimed in claim 1, wherein the adapter tip has a substantially elongated hollow member and wherein the optical head is configured so that, when interconnected, at least part of the optical head interlocks into the hollow member of the adapter tip so that the relay lens of the optical head is positioned within the adapter tip.

12. An optical-fiber connector endface inspection microscope system for inspecting an endface of an optical-fiber connector, the optical-fiber connector endface inspection microscope system comprising: one or more image detector for capturing at least one image of the endface to be inspected; an objective lens system comprising a focusing lens for adjusting a focus of the objective lens system on the image detector; a main housing structure enclosing the image detector and the focusing lens; and a multi-fiber optical head comprising and a single-fiber optical head, configured to interchangeably and releasably connect to the main housing structure and each enclosing a fixed relay lens; wherein the multi-fiber optical head and a single-fiber optical head are each releasably connectable to an adapter tip for interfacing with the optical-fiber connector to be inspected.

13. The optical-fiber connector endface inspection microscope system as claimed in claim 12, further comprising: at least one multi-fiber adapter tip releasably connectable to the multi-fiber optical head and comprising a multi-fiber optical-fiber connector interface for mechanically engaging with a multi-fiber optical-fiber connector to be inspected; and at least one single-fiber adapter tip releasably connectable to the single-fiber optical head and comprising a single-fiber optical-fiber connector interface for mechanically engaging with a single-fiber optical-fiber connector to be inspected.

14. The optical-fiber connector endface inspection microscope system as claimed in claim 12, wherein the relay lens of the multi-fiber optical head and the relay lens of the single-fiber optical head have mutually different dimensions.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is an exploded perspective view showing an optical-fiber connector endface inspection microscope system in accordance with one embodiment.

[0028] FIG. 2 is a side elevation view of the inspection microscope system of FIG. 1.

[0029] FIG. 3 is a side elevation view of an optical-fiber connector endface inspection microscope system in accordance with one embodiment comprising an angled optical head.

[0030] FIG. 4 comprises FIG. 4A, FIG. 4B and FIG. 4C wherein FIG. 4A is a front elevation view of the inspection microscope system of FIG. 1; FIG. 48 is a cross-sectional view of the same, taken along line D-D of FIG. 4A; and FIG. 4C is a perspective view of the inspection microscope system of FIG. 1.

[0031] FIG. 5 comprises FIG. 5A, FIG. 5B and FIG. 5C wherein FIG. 5A is an isometric view of the multi-fiber optical head of the inspection microscope system of FIG. 1;

[0032] FIG. 5B is a front elevation view of the same; and FIG. 5C is a cross-sectional view of the same, taken along line C-C of FIG. 5B.

[0033] FIG. 6 comprises FIG. 6A, FIG. 6B and FIG. 6C wherein FIG. 6A is an isometric view of the single-fiber optical head of the inspection microscope system of FIG. 1; FIG. 6B is a front elevation view of the same; and FIG. 6C is a cross-sectional view of the same, taken along line E-E of FIG. 6B.

[0034] FIG. 7 comprises FIG. 7A, FIG. 7B, FIG. 7C and FIG. 7D wherein FIG. 7A is an isometric view of the angled optical head of the inspection microscope system of FIG. 1; FIG. 7B is a left-side elevation view of the same; FIG. 7C is a front elevation view of the same; and FIG. 7D is a cross-sectional view of the same, taken along line A-A of FIG. 7C.

DETAILED DESCRIPTION

[0035] Referring to FIGS. 1 to 7, there is provided an optical-fiber inspection microscope system 100 for inspecting an endface of an optical-fiber connector and which can be configured into either a single-fiber inspection microscope or a multi-fiber inspection microscope. The system 100 comprises a main housing structure 10 and mutually interchangeable optical heads, such as a multi-fiber head 12 and a single-fiber head 14.

[0036] FIG. 5 shows the multi-fiber optical head 12 in more details and FIG. 6 shows the single-fiber optical head 14 in more details. Each optical head 12, 14 is designed specifically for one of the main families of connectors, e.g., single-fiber or multi-fiber. Each optical head 12, 14 includes a relay lens 16, 18, that is positioned in the optical head so as to be located close to the connector endface under inspection, i.e., near the inspection end of the optical-fiber inspection microscope system 100. Each optical head 12, 14 brings an optical component usually part of the fiber inspection scope (i.e., the relay lens 16, 18) as an external element that is made interchangeable by swapping optical heads 12, 14. This interchangeability allow to configure the inspection microscope system 100 into either a single-fiber or a multi-fiber inspection microscope.

[0037] It is noted that the region of interest on a mufti-fiber ferule is about 4.3 mm wide while the single-fiber is less than 1 mm. Knowing that to be able to efficiently inspect optical-fiber connectors, the adapter tip of the inspection microscope, and therefore the optical head must be small enough to avoid any physical interference with adjacent connectors (e.g., in a densely populated patch panel), the mufti-fiber relay lens 16 and the single-fiber relay lens 18 may therefore be optimally made with mutually different dimensions. They may be dimensioned so as to each capture the whole surface of the optical-fiber connector under inspection, while keeping the optical head and adapter tip no bigger than necessary so as to not mechanically interfere with adjacent connectors, The multi-fiber relay lens 16 may therefore be made wider than the single-fiber relay lens 18.

[0038] This configuration also allows the use of inexpensive adapter tips, such as tips 20 or 22, which do not include lenses in order to complete the adaptation to each connector “sub-type” (e.g., MPO APC, MPO UPC, Optitip, Q-ODC, etc.). These adapter tips are interchangeably connectable to its corresponding optical head. Each interchangeable adapter tip is configured to interface with one or more specific optical-fiber connector to be inspected. The single-fiber optical head 14 is made releasably connectable to single-fiber adapter tips and the mufti-fiber optical head 14 is made releasably connectable to mufti-fiber adapter tips.

[0039] Users who want to switch from one family of connectors to another can simply swap optical heads 12, 14. Switching from one to another does not add any extra optical and mechanical components in the optical path and the image quality and size of the inspection microscope system can be optimal for both single-fiber and multi-fiber connector inspection. As explained hereinabove, switching heads instead of adding an adaptor may also provide the benefit of minimizing the mechanical tolerance stack-up of the system.

[0040] As illustrated herein, adapter tips (20, 22 or other non-illustrated tips) each comprise a substantially elongated hollow member 60 defining a channel 62 between a proximal end 64 and a remote end 66, wherein illumination light may propagate to and back from the inspected connector endface. It further comprises an optical connector interface 68 at its proximal end 64 to mechanically engage with the optical connector (not shown) during inspection, as well as a connection mechanism 52 for releasable connection to the optical head (12, 14, 24 or other non-illustrated optical head) and having complementary engaging features 70, 72 respectively located on the adapter tip and the optical head.

[0041] Similarly, optical heads (12, 14, 24 or other non-illustrated optical heads) each comprise a substantially elongated hollow member 80 defining a channel 82 between a proximal end 84 and a remote end 86, wherein illumination light may propagate to and back from the inspected connector endface. It further comprises a relay lens 16 or 18 at its proximal end 64 and a connection mechanism 50 for releasable connection to the main housing 10 and having complementary engaging features 90, 92 respectively located on the optical head and the main housing 10.

[0042] When in use for connector endface inspection, at least part of the elongated member 80 of the optical head may interlock into the hollow member 60 of the adapter tip so that the relay lens 16 or 18 of the optical head is positioned within the adapter tip. This configuration allows the relay lens 16 or 18 be located close to the connector endface under inspection, i.e., near the inspection end of the optical-fiber inspection microscope system 100.

[0043] Each interchangeable optical head (12, 14, 24 or other non-illustrated optical head) may be made easily releasably connectable to the main housing structure 10 using a connection mechanism 50 such as a screw-threaded mechanism or twist and lock mechanism for example. Similarly, the adapter tip 20 or 22 may be made releasably connectable to the optical head 12 or 14 using a similar connection mechanism 52.

[0044] Referring to FIGS. 2, 3 and 7, the interchangeable optical head can also be used to change the orientation of the connector under inspection relative to the optical-fiber inspection microscope in order to allow to reach optical-fiber connector bulkheads that are disposed at an angle within the patch panel.

[0045] For such applications, switching heads instead of adding an adaptor may advantageously allow a more ergonomic design. Without interchangeable heads, an angled adapter would need to be inserted between the optical-fiber connector bulkhead to be inspected and the optical-fiber inspection microscope. The overall inspection system would be longer and less ergonomic.

[0046] In this case, the optical-fiber inspection microscope system 100 further comprises and angled optical head 24 that is interchangeable with one or more linear optical head such as the multi-fiber head 12 or the single-fiber head 14. FIG. 7 shows the angled optical head 24 in more details, The angled optical head 24 can be made either multi-fiber or single-fiber. The angled optical head 24 also includes a relay lens 26, that is positioned in the optical head so as to be located close to the connector endface under inspection. In addition, the angled optical head 24 further comprises a mirror 30 used to deviate an optical path between the inspected connector endface and the main housing structure 10 and so allow to create an angle in the optical head 24. Depending on the actual design, additional lenses 28 may also be needed in the angled optical head 24 in order to relay the illumination light to and back from the inspected endface and extend the optical path of the angled optical head 24 compared to the single-fiber optical head 14 and the multi-fiber optical head 12.

[0047] In some embodiments, the multi-fiber angled head 24 may be manufactured so its proximal portion which inserts in and engage to adapter tips 20 is identical or has substantially the same shape as that of the multi-fiber head 12, so as to allow to interchangeably use the same adapter tips 20 for both heads 12, 24. The same can be applied to a single-fiber angled head and the single-fiber head 14.

[0048] Referring to FIG. 4, which comprises FIG. 4A and FIG. 4B, the optical-fiber connector endface inspection microscope system 100 of FIG. 1 is shown in more details. In FIG. 4, the inspection microscope system 100 is illustrated with optical head 12 but could likely have been illustrated with optical head 14.

[0049] It will be understood that the configuration of FIG. 4B illustrates one example embodiment of an optical-fiber connector endface inspection microscope system. It should be appreciated by those of ordinary skill in the art that various implementations of the inspection microscope can be envisaged as known in the art and that the embodiment illustrated herein is no way meant to be limitative.

[0050] Generally, an optical-fiber connector endface inspection microscope system 100 incorporates an imaging assembly comprising an illumination source 30 for illuminating the connector endface to be inspected (not shown), an illumination beam splitter 32 to direct illumination light toward the connector endface, one or more image detector 34 (herein two image detectors) for capturing at least one image of the endface to be inspected, and imaging optics. The imaging optics comprises an objective lens system (and optionally other lenses, mirrors (see, e.g., 38) and/or other optical components (e.g., beamsplitter 48) defining objective optics), for imaging the illuminated connector endface, on the image plane(s) coinciding with the image detector(s) 34. The object plane as defined herein is determined by the objective lens system and coincides with the plane where the connector endface to be inspected (i.e., the object) should be positioned (within the focusing range of the objective lens system) to be suitably imaged on the image detector(s) 34. The optical path between the object plane and the image plane defines an imaging path of the inspection microscope, along which propagates the inspection light beam resulting from a reflection of illumination light on the connector endface, for optical magnification of the object (i.e., the connector endface) positioned on the object plane.

[0051] More specifically, the objective lens system comprises a focusing lens 36 for adjusting a focus of the objective lens system on the image detector(s) 34 and a fixed relay lens (here lens 16) disposed in the optical head (here 12), whereas the image detector(s) 34 and the focusing lens 36 are enclosed in the main housing structure 10.

[0052] The objective lens system at least comprises the focusing lens 36 for adjusting a focus of the objective lens system on the image detector and a fixed relay lens 16 or 18. In the embodiment of FIG. 4, the focus is adjusted by moving the focusing lens using an actuator 46. It will be understood that the objective lens system may further comprise other lenses or optical elements as required by the optical design, which lenses and optical elements can be either fixed relative to the microscope system or movable, e.g., held fixed with the focusing lens. For example, in the embodiment of FIG. 4, the objective lens system may further comprise lens 40 that is enclosed and held fixed within the main housing structure.

[0053] One drawback of having one moving lens and one fixed is that, without any special care, the magnification level could then depend upon the focus (i.e., the position of the focusing lens). However, optical-fiber inspection microscopes are not only required to produce high-quality images on small elements, but they are also required to precisely measure defects on inspected optical fiber connector endfaces. Having different magnification levels can be problematic for such applications. This drawback may be overcome by providing a telecentric objective comprising a telecentric aperture stop.

[0054] In the embodiment of FIG. 4, the objective lens system is thereby configured to form a telecentric objective and comprises a telecentric aperture stop 42.

[0055] A telecentric aperture stop is an aperture stop that is positioned at the focal point in an optical system, in order to reduce magnification variations caused by a slight displacement of the object plan. Here, the aperture stop is positioned at or near the focal point of the objective lens system, i.e., at or near the focal point of the relay lens 16 or 18.

[0056] In the embodiment of FIG. 4, the aperture stop 42 and the focusing lens 36 are together mounted in a lens holder 44. The distance between the two therefore remains fixed during focus. Focus is being adjusted by displacing the lens holder 44 using an actuator 46, thereby moving the focusing lens 36 and the aperture stop 42. During focus adjustment, the relay lens 16 or 18 and other optical elements of the objective lens system remain fixed within the inspection microscope system 100. Consequently, the distance between the aperture stop 42 and the relay lens 16 or 18 varies during focus adjustment but nevertheless remains close to the focal point of the relay lens 16 or 18 so as to obtain a substantially telecentric objective lens system.

[0057] Another issue related to the focus being done by the second group of lenses is the higher level of mechanical tolerance and more importantly the level of positioning precision being required. This issue may be solved herein by arranging the optical components in a way which allows a longer travel for the focusing lenses to achieve a similar focus range on the object.

[0058] It will be understood that numerous modifications may be made to the embodiments described herein without departing from the scope of the invention.

[0059] For example, focus may be adjusted using a deformable focusing lens instead of a movable focusing lens. In such case, both the focusing lens 36 and the relay lens 16 or 18 remain fixed during focus adjustment but the magnification may still depend upon the focus, i.e. the adjusted focal point of the deformable focusing lens. As in the embodiment of FIG. 4, this drawback may be overcome with a telecentric objective comprising a telecentric aperture stop.

[0060] The embodiments described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the appended claims.