Patent Grant
8824068
The invention relates to methods and devices for fabricating optical instrumentation.
Various assembly methods such as those using adjustable and modular mounts for optical components and pick-and-place assembly are utilized to fabricate optical instruments.
One embodiment of the present invention provides a system for fabricating an optical bench. The system includes a jig configured for temporarily coupling with an optical bench to be populated with one or more optical components, the jig having one or more shaped apertures in its surface so as to designate a predetermined placement location of a corresponding optical component on to the optical bench. In some cases, at least one of the shaped apertures is associated with a clamp for securely positioning a corresponding optical component at its predetermined position on the optical bench. In some cases, the jig is configured to allow a plurality of optical components to be simultaneously bonded to the optical bench. In some cases, each of the apertures is configured with a plurality of alignment bumps. In some such cases, each of the apertures is configured with three alignment bumps arranged in an orthogonal relationship. In some cases, each of the optical bench and jig is associated with an X-Y coordinate system, and the jig is configured to temporarily couple with the optical bench so that the X-Y coordinate system of the jig is aligned with the X-Y-Z coordinate system of the optical bench. In other cases, each of the optical bench and jig is associated with an X-Y-Z coordinate system, and the jig is configured to temporarily couple with the optical bench so that the X-Y-Z coordinate system of the jig is aligned with the X-Y-Z coordinate system of the optical bench. In some cases, the jig is further configured with one or more support posts configured for engaging a corresponding contact pad of the optical bench. In some cases, the jig is further configured with one or more optical bench clamps configured for securing the optical bench. In some cases, the jig is configured with a plurality of contact points configured to interface with corresponding contact points on the optical bench. In some cases, the jig is configured with a major recessed area that is shaped to receive the optical bench. In some such cases, a perimeter of the recessed area includes a plurality of contact points each configured to interface with corresponding contact point on the optical bench. Numerous variations will be apparent in light of this disclosure. For instance, another embodiment provides a method of fabricating an optical bench, the method comprising use of the jig as variously defined in this paragraph to fabricate the optical bench.
Another embodiment of the present invention provides a system for fabricating an optical bench. In this example case, the system includes a jig configured for temporarily coupling with an optical bench to be populated with one or more optical components, the jig having one or more shaped apertures in its surface so as to designate a predetermined placement location of a corresponding optical component on to the optical bench, wherein each of the apertures is configured with a plurality of alignment bumps, and wherein the jig is further configured with a plurality of contact points configured to interface with corresponding contact points on the optical bench. The system further includes a clamp associated with each aperture and for securely positioning a corresponding optical component at its predetermined position on the optical bench. Each of the optical bench and jig is associated with an X-Y-Z, coordinate system, and the jig is configured to temporarily couple with the optical bench so that the X-Y-Z coordinate system of the jig is aligned with the X-Y-Z coordinate system of the optical bench. In some cases, the jig is configured to allow a plurality of optical components to be simultaneously bonded to the optical bench. In some cases, each of the apertures is configured with three alignment bumps arranged in an orthogonal relationship. In some cases, the jig is further configured with one or more support posts configured for engaging a corresponding contact pad of the optical bench, in some cases, the jig is further configured with one or more optical bench clamps configured for securing the optical bench.
Another embodiment of the present invention provides a system for fabricating an optical bench. In this example case, the system includes a jig configured for temporarily coupling with an optical bench to be populated with one or more optical components, the jig having one or more shaped apertures in its surface so as to designate a predetermined placement location of a corresponding optical component on to the optical bench. Each of the apertures is configured with a plurality of alignment bumps. The jig is further configured with a major recessed area that is shaped to receive the optical bench, and a perimeter of the recessed area includes a plurality of contact points each configured to interface with corresponding contact point on the optical bench. The system further includes a clamp associated with each aperture and for securely positioning a corresponding optical component at its predetermined position on the optical bench. Each of the optical bench and jig are associated with an X-Y-Z coordinate system, and the jig is configured to temporarily couple with the optical bench so that the X-Y-Z coordinate system of the jig is aligned with the X-Y-Z coordinate system of the optical bench. Another embodiment provides a method that includes use of the jig as variously described in this paragraph to fabricate the optical bench.
The features and advantages described herein are not all-inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and not to limit the scope of the inventive subject matter.
a-1c each illustrate top-side perspective view of an optical assembly system for a given optical bench design, configured in accordance with an embodiment of the present invention.
a-2c each illustrate a bottom-side perspective view of the optical assembly system of
a-3b each illustrate a detailed partial perspective view of the optical assembly system of
Techniques are disclosed, for fabricating optical instrumentation. The techniques can be used, for instance, to populate an optical bench with several optics that can be simultaneously bonded and then simultaneously verified to very precise assembly, without the use of adjustable mounts or active alignment. In some such embodiments, the techniques are embodied in a jig that is designed for operatively coupling to a given optical bench. The jig includes cut-outs that identify precise placement locations for the various optical components on the underlying optical bench. Thus, once the jig is secured to the optical bench, precise placement of the optical components is greatly simplified. In some such embodiments, the jig further includes a clamping assembly for each cut-out, so that once an optical component is placed on the optical bench in that cut-out, the clamping assembly can be engaged to hold that optical component in place while the underlying bonding agent (e.g., epoxy or other adhesive) disposed between the component and the optical bench is cured.
General Overview
As previously explained, optical instrumentation can be manufactured using various methods that typically include adjustable mounts or pick-and-place machines that rely on computer vision for proper positioning. However, there are number of non trivial problems associated with such methods and manufacturing systems. For instance, fabricating, assembling, and integrating complex optical instruments using adjustable mounts throughout the optical train can be costly and slow. Modular components such as optics holders on rails are available, but are generally designed for a laboratory environment; and not for the rigors of demanding environments such as those associated with flight-based applications susceptible to extreme temperature variations and/or vibration profiles. Nor are such modular component holding solutions always suitable for a given set of packaging requirements. In still other cases, typically with respect to less complex optical devices such as small designator lasers having only a few optical elements and which are built using so-called “active alignment” of glass-to-metal with no mounts, optical instrumentation is required to monitor the position of the optic as it is manually aligned using precision motion equipment. Pick-and-place assembly also uses active alignment and can require large capital expenditures for automated assembly computer vision machines and software, as well as for the associated maintenance costs. In addition, pick-and-place methods can be slow, unless many replications of the very expensive machines are put into service. For a complex, expensive product that might only see production of for instance, 1000 units or less, recovery of such capital expenditures is doubtful or simply not attainable. In short, such fabrication procedures use active alignment to slowly place each optic into position, then verify, then bond, then re-verify.
Thus, and in accordance with an embodiment of the present invention, a system for manufacturing an optical instrument is provided. The system includes a jig that is mechanically customized to a given optical bench design. The jig operatively couples to the optical bench in a specific manner, and includes cut-outs that identify precise placement locations for the various optical components on the underlying optical bench. Thus, once the jig is secured to the optical bench, precise placement of the optical components is enabled.
In some such embodiments, the jig further includes a clamping assembly for each cut-out, so that once an optical component is placed on the optical bench in that cut-out, the clamping assembly can be engaged to hold that optical component in place while the underlying epoxy or other bonding agent disposed between the component and the optical bench is cured. Given that multiple components of the optical train can be relatively quickly placed and secured, the bonding process of each component can effectively take place simultaneously. Likewise, once the optical components are placed, the beam propagation path can be quickly verified to ensure proper alignment is met prior to completion of the curing process.
In some embodiments, the techniques provided herein can be used, for instance, to replace one or more adjustable mounts in a given optical bench design, especially those that form the framework of the optical path from input to output, with precisely but passively located and fixed optical elements that are similar in shape and precision to alignment cubes. In some embodiments, the optical elements are uniform in size and shape and/or are otherwise configured with highly orthogonal sides. As will be further appreciated in light of this disclosure, the techniques provided herein enable the use of a substantially flat optical bench (no upward protruding features whatsoever, such as mounting features). As such, the optical bench can be can be smaller in area because mounts can be eliminated or otherwise reduced, as well as lighter because it is smaller, and thinner because it is lighter. The relatively inexpensive jig can be used to locate all (or a sub-set) of the optical elements that form the framework of the optical path, and further enables simultaneously bonding of these optical elements into place onto the optical bench using a given adhesive and bond geometry.
The jig further enables fast and efficient verification of the location of the planes and surfaces of each optic. In some embodiments, this verification can be carried out using a commonly available coordinate measuring machine (CMM), but the claimed invention is not intended to be limited to use of such equipment. Numerous other verification processes will be apparent in light of this disclosure (e.g., visible beam based verification such as a green beam that demonstrates the optical train is functional for its intended purpose; detector based verification where a beam is propagated through the optical train from an input to an output monitored by a detector).
In any such cases, the jig can be used to allow a substantial portion of the optical bench assembly process to be performed in a matter of minutes instead of days or even weeks, including the verification process. In addition, the populated optical elements can be aligned to a very high degree (approaching perfectly aligned in some embodiments), making the rest of the alignment task significantly easier, and leading to fewer incidents of damage to misalignments as the build progresses. In some such embodiments, a CMM output of optical surface locations and orientations serves as a useful record of minor initial misalignments, should they cause more misalignment down the optical path. Because the jig can be implemented in a relatively inexpensive fashion (e.g., two or three orders of magnitude less than a pick-and-place machine, for instance), a large number can be put into service simultaneously and at a reasonable cost. Also, simultaneous passive bonding followed by simultaneous CMM inspection in accordance with some embodiments is very fast compared to, for example, pick-and-place active alignment and verification, as will be appreciated. In accordance with one embodiment of the present invention, the CMM inspection process involves contacting the CMM probe tip on multiple locations of the optical bench and each optical element populated thereon and recording the position (X-Y coordinates) of the probe tip at each of those locations. In one such case, the probe tip is contacted on three locations of a first side of each optical element on three locations of a second side of each optical element, wherein the first probed side and the second probed side are orthogonal to each other. The three locations of each side may correspond, for example, to three of the four corners of that side. The CMM software converts the measured probe coordinates into the coordinate system of the optical bench assembly, thereby allowing for confirmation of the build.
Jig Assembly
a-1c each illustrates a top-side perspective view of an optical assembly system, configured in accordance with an embodiment of the present invention. As can be seen, the system includes a jig mechanically customized to couple with a given optical bench. The jig includes a frame supporting a number of optical component clamp assemblies. The jig frame further includes a number of optical element cut-outs configured with alignment bumps (the alignment bumps are further illustrated in
As will be appreciated, the optical bench and optical components populated thereon are shown in
The jig-assembly can be made out of any suitable material, such as aluminum, steel, or a pressure molded plastic. It is specifically designed and configured to op rate with a given optical bench design, and the specific configuration will vary from one application to the next, as will be appreciated in light of this disclosure. Thus, for example, the number and dimensions of the optical element cat-outs will vary, as will the overall dimension and shape of the jig frame perimeter.
In the example embodiment shown, most of the optical component clamping assemblies are implemented as spring-loaded clamps that are operatively coupled to a corresponding clamp support post bolted or otherwise fastened to the jig frame. Thus, the spring-loaded clamps can rotate about the post, and can be adjusted up or down the post as well. One of the optical component clamping assemblies is configured as a turn-screw clamp. The clamping assemblies can be implemented with any number of suitable materials, such as steel, aluminum, or plastic, or a combination of such materials. Any number of suitable clamping configurations and materials can be used, whether spring-based or otherwise, so long as the optical component is sufficiently secured to the optical bench according to a given specification.
a-2c each illustrate a bottom-side perspective view of the optical assembly system of
To further assist in the coupling-alignment process between the jig assembly and the optical bench to be populated, the jig assembly can be further configured with a number of bench support posts, as shown in the example embodiment of
As can be further seen in
In other embodiments, note that the jig frame may not include a major recess like, the one shown in
In any such embodiments, one or more turn-screws can be threaded into the turn-screw holes residing in opposing sides of the jig frame, so that the end of the turn-screw contacts or otherwise engages a corresponding side of the optical bench and effectively secures the optical bench up against the opposing contact point(s). In some such embodiments, the turn-screw ends can be coated with hardened rubber to prevent scratching, or gauging of the optical bench perimeter, if so desired.
As will be further appreciated, the number of contact points can vary, and other embodiments may include fewer such points (e.g., two contact points) or more such points (e.g., six contact points). The number of contact points will depend on factors such as the available area that can be dedicated to such contact points on the optical bench, the perimeter shape of the optical bench, and the desired degree of coordinate system alignment (in general, the greater the number of contact points, the greater the degree of alignment of the jig and bench coordinate systems).
b shows a bottom-side perspective view of the optical bench installed into the jig frame, in accordance with an embodiment of the present invention. Note that in some such embodiments, the optical bench fits snugly into the jig frame recess and no further holding mechanism is necessary. In other embodiments, one or more turn-screws can be used to secure the optical bench into the jig frame. Some example threaded turn-screw holes are shown in
Once the optical bench is secured in place within the jig frame, the various optical components can then be populated onto the bench. An optical element may be, for example, a lens, prism, window, beam splitter, or other element that is used in an optical instrument or application. As will be further appreciated, an optical bench may be prepared with a single type of optical element or with a combination of different types of optical elements. In general, selection of optics and their positions will be determined based on the application of the optical instrument being manufactured. In some specific embodiments, fixed optical elements that are similar in shape and precision to alignment cubes are used. However, any optical element shape that is amenable to being populated directly on the optical bench can be used, and the claimed invention is not intended to be limited to cube-shaped optical elements. As will be appreciated in light of this disclosure, using a substantially uniform optical element shape and size profile for the optical components to be populated on the optical bench is helpful in simplifying the fabrication process, particularly when the optical elements have highly orthogonal sides. Thus, and in accordance with some embodiments of the present invention, 90% or more of the optics to be populated using the jig are the same size and shape, within a given acceptable tolerance. In still other embodiments, all of the optics to be populated using the jig are the same size and shape, within a given acceptable tolerance.
In some embodiments, an adhesive may be positioned at one or more locations on the optical bench for each predetermined location for a given one of the optical elements, prior to placement of the corresponding optical element. Note, however, that adhesive may be positioned on an optical bench surface or may be positioned onto an optical element itself or on both the optical bench and optical element. If positioned on the optical bench, adhesive may be positioned in specific predetermined optical element attachment locations on the optical bench. For instance, in one example embodiment, three dots of epoxy are deposited for each optical element, such that when the optical component is secured in position, the corresponding optical component clamp assembly applies a force having a vector that generally passes on an angle through the optical element and a center of the three dots of epoxy. The force vector is sufficient to secure the element against the alignment bumps in the cut-out.
Various adhesives may be used to attach an optical element to the given optical bench, including any number of suitable epoxies, glues, bonding materials, and any suitable means to adhere an optical element to an optical bench. An adhesive may be rapid drying, rapid curing adhesive. An adhesive may be a synthetic or a natural adhesive, or a combination thereof. In some embodiments, the bonding agent is an adhesive that cures by evaporating a solvent or by a chemical reaction that occurs between two or more constituents of the adhesive. The adhesive may be, for instance, heat cured, air-cured, or ultraviolet (UV) cured. In some specific example cases, the adhesive includes a uniform particulate (e.g., glass or plastic beads) that enable a self-shimming glue line, as will be appreciated.
a-3b each illustrate a detailed partial perspective view of an example optical assembly system, configured in accordance with an embodiment of the present invention. As can be seen, the clamp is shown in the clamped position in
As can be further seen, the clamp assembly includes a drop-away support.
The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. For instance, note that once the jig is operatively coupled to the optical bench, automatic placement can be carried out, for instance, using robotics or other pick and place technology, if so desired. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
This application claims the benefit of and priority to U.S. Provisional Application No. 61/481,053, filed on Apr. 29, 2011, which is herein incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/US2012/032961 | 4/11/2012 | WO | 00 | 1/10/2013 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2012/148662 | 11/1/2012 | WO | A |
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| Number | Date | Country | |
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| 20130163103 A1 | Jun 2013 | US |
