This disclosure relates to optical faceplates used in various applications including light and image transfer, and more particularly to optical faceplates and manufacturing methods that employ embossed optical fibers transversely disposed to an optical substrate.
Fiber optic faceplates, in which light is transmitted from or to a source or detector, are used for high resolution, zero thickness light and image transfer in applications that may include CCD/CMOS coupling, laser array/fiber array coupling, CRT/LCD displays, image intensification, remote viewings, field flattening, X-ray imaging, and molecular diagnostics like in genomics, proteomics, drug discovery and micro-fluidic systems. Although the advantages of fiber optics are clear and proven, various problems and limitations exist in manufacturing these plates.
Current problems in manufacturing of optical faceplates include difficulties in bundling thin optical fibers to a desired diameter, bonding them together followed by cutting and polishing the bundled fibers to the desired thickness. There is also room for improvement in manufacturing faceplates with fibers having smaller sizes (below 10 micron), to control diameter and parallel alignment between the individual fibers. In addition, current manufacturing processes do not provide an efficient way to vary the center-to-center spacing between the fibers, and do not provide differently shaped fibers (e.g. ovals, squares, hexagons, octagons, etc.).
Another recognized problem is providing the precise alignment of the fibers with respect to the pixels of a detector, such as CCD or CMOS sensors to avoid cross talk. The complexity of conventional face plate fabrication results in an expensive manufacturing process.
In accordance with present embodiments, optical faceplates and methods for manufacturing same are disclosed. An optical faceplate includes a substrate having a major surface, and an array of optical fibers embossed on the substrate. The optical fibers have a length determined in accordance with a layer of material deposited on the substrate from which the optical fibers are formed, a depth of the features in a mold or stamp and a number of processing/stamping steps. A method includes forming a layer on a substrate having a major surface, and processing the layer to form an array of optical fibers transversely disposed to the major surface.
These and other objects, features and advantages of the present disclosure will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings.
This disclosure will present in detail the following description of preferred embodiments with reference to the following figures wherein:
The present disclosure describes optic faceplates which may be employed in applications including but not limited to charge-coupled device (CCD)/complementary metal oxide semiconductor (CMOS) coupling, laser array/fiber array coupling, cathode ray tube/liquid crystal display (CRT/LCD) displays, image intensification, remote viewings, field flattening, X-ray imaging such as radiography and mammography, and molecular diagnostics like in genomics, proteomics, drug discovery, micro-fluidic systems and others. Currently, such plates are produced by bundling thin optical fibers to a desired diameter, bonding them together followed by cutting and polishing the device to the desired thickness. This is a difficult process with various limitations. In accordance with the present principles, a method for manufacturing optical plates is disclosed. The method involves embossing a desired height and aspect ratio structure on top of a desired substrate which can be a functional unit (detector, etc.). This may be followed by filling areas around the embossed fibers if necessary with a low refractive material or other functional materials. Functional materials may be deposited on the fibers as well. These functional materials may include, for example, target-specific affinity probes deposited onto the optical faceplate.
It should be understood that the present invention will be described in terms of optical faceplates with embossed optical fibers. However, the teachings of the present invention are much broader and are applicable to array based attachment methods for fibers in a transverse orientation with respect to a substrate that carries or secures the fibers. The fibers may be mounted on, positioned on or otherwise placed on a substrate using a plurality of different technologies. Embodiments described herein are preferably fabricated using a printing process; however, lithographic imaging and processing may also be employed. Other processing techniques are also contemplated.
It should also be understood that the illustrative example of the optical faceplates may be adapted to include additional electronic/optical components. These components may be formed integrally with the substrate or mounted on the substrate or other components (e.g., on the fibers). In addition, the components employed may vary depending on the application and the design. The elements depicted in the FIGS. may be implemented in various combinations of hardware and provide functions which may be combined in a single element or multiple elements.
Referring now to the drawings in which like numerals represent the same or similar elements and initially to
By printing or stamping the optical faceplate 10, described limitations in conventional bundling of the optical fibers, bonding them together followed by cutting and polishing them to a desired thickness, are advantageously addressed. The fibers 14 formed in accordance with the present principles, especially with smaller diameters (e.g., below 10 microns), are individually aligned and can be more easily manufactured. The method is also suitable for producing fibers with nanometer dimensions (nano-fibers). This method of manufacturing also permits the control of various array dimensions, e.g., center-to-center spacing between the fibers 14, the shape of the fibers (e.g. ovals, squares, hexagons, octagons, etc.), and fiber tip shapes. Such dimensions, shapes and spacings are advantageously predetermined in a die/stamp or pre-patterned in a lithographic masking operation.
It also should be understood that the present principles afford a great amount of flexibility in the fabrication of optical fibers. For example, the cross-sectional shapes of fibers and spacings between fibers may be varied over the same device or substrate. In other words, the fibers' density and individual sizes of fibers may be varied over a surface. Also, the cross-sectional shapes and widths may be varied and mixed over the surface. In addition, the top surface shape of the fibers can be varied to be dome shaped, flat, pyramidal, curved, etc. Furthermore, the dimensions of the fiber may also vary along the fiber axis. Such structures may be varied and mixed along the surface. For example, tapered fibers can also be produced.
Precise positioning of optical fibers 14 relative to the substrate 12 is advantageously achieved. For example, if substrate 12 includes a source or a detector such as CCD or CMOS sensors, precise positioning of fibers 14 can be provided at particular positions on the substrate 12 that can optimize or improve performance. Further, the bonding of an optical face plate to a source or detector is improved resulting in improved transmission efficiency, and reduced cost. Fibers can be bonded to the surface chemically. This can be achieved by treating the surface using reactive molecules which can subsequently react with the layer. It can also be just a physical adhesion.
Various materials can be used in the formation of fibers 14. In a particularly useful embodiment, a sol-gel material, which shows low polymerization shrinkage and becomes chemically attached to the surface, may be employed. In one embodiment, a liquid material is deposited (e.g., spun on) and solidified , by evaporation of the solvent and/or cross-linking by heat or light. For optical face plates 10, these materials have desired and improved optical properties (e.g. optimal numerical aperture, high transmission) for this application while being thermally and chemically stable (no degradation or discoloring). Examples of curable materials may be selected from the group of (metha)acrylate, epoxies oxetanes, vinyl ethers, alkoxides such as the alkoxysilanes tertramethoxysilane (TMOS), tetraethoxysilane (TEOS), methyltrimethoxysilane (MTMS) or other suitable materials.
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It should be understood that a plurality of layers may be stacked onto each other in a number greater than two. In addition, sections of the stacked fibers 24 may be formed coaxially as shown in
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Immobilization of the target-specific affinity probes 54 onto the optic faceplate can be achieved in different ways including chemical binding of the probes 54 to the faceplate 10 or 20. Probes 54 may include different biological receptors for detecting DNA, RNA, proteins, cells, tissue, or any kind of biological molecule or organism of interest.
Optic faceplates can be used for high throughput methods of molecular diagnostics. The components may be employed in many applications, for example, genomics, proteomics, drug discovery and micro-fluidic systems to name a few. Optic faceplates have the advantage of having an extremely high number of optical elements and reaction sites. They provide interference free separation of reaction sites via microwells or capillaries. Using fiber optic technology, superior readout of individual optical channels can be obtained. This permits high sensitivity, repeatability and low background fluorescence.
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Although the advantages of fiber optics for digital radiography are clear, problems may exist in manufacturing and bonding such fiber optic faceplates to scintillators and CCD or CMOS imagers using conventional technologies. It is important that the fibers are aligned with the pixels of the detector. Distortion and response non-uniformity, which degrade image quality, should be reduced. Higher degrees of alignment of the fibers with respect to pixels are achieved by bonding or embossing fibers to a substrate (e.g., directly to the CCD or CMOS imager) in accordance with the present principles. Precise, robust, reliable attachment is provided by stamping the fiber gel or using photolithography to cross-linked layers. In addition, higher image quality is provided by increasing the number of fibers delivering light to each sensor pixel. For example, a 6 micron fiber diameter can provide 16 fibers to a 24 micron pixel; however, many more fibers can be provided in accordance with the present principles, since fibers with a small diameter (even on the nanometer scale) can be manufactured. Density, size, shape and location of fibers can easily be varied across a substrate.
The present principles provide improved transmission efficiency, precise and robust attachment of the fiber optic faceplate, and decreased distortion and response non-uniformity to maximize image quality and durability. In addition, faceplates can be manufactured with fibers having specific shapes (e.g. ovals, squares, hexagons, octagons, etc.) and smaller sizes (e.g., below 15 micrometers and into the nano-meter range) as described above. Also the top surface shape of the fibers can be varied to be dome shaped, flat, pyramidal, curved, etc. Furthermore, the manufacturing method in accordance with the present embodiments is lower in cost.
In embodiments of the present invention, fiber optic faceplates have been manufactured using crosslinking materials. Micrometer and even nanometer structures with various shapes and high aspect ratios (1:10) have been produced on various surfaces having different roughness or profiles.
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In an optional step 203, a filling material may be formed around the previous layer of fibers. This is so that a plurality of layers may be formed to create a stacked optical faceplate. After processing in blocks 202 through 210 is completed, as needed, filler material is applied instead of or in addition to the radiation blocking material (of block 210). A second layer (block 202) is formed and processed in accordance with steps 202, 204, 206, 208 and 210, as needed. This can continue for as many layers as needed. The plurality of the layers forms the array of optical fibers such that each layer provides a portion of a length of the entire optical fibers.
In block 206, the processing may include stamping or embossing the layer(s) to form the array of optical fibers. The stamping preferably includes applying the stamp with e.g. a wave like motion to avoid voids and air bubbles after alignment. The stamping process further includes controlling at least one of a spacing between fibers, a cross-sectional shape of the fibers and a tip geometry of the fibers. This may be performed using the features provided on the stamp.
In block 208, the array of fibers may be etched or heated to remove material between the fibers. Etching may include a reactive ion etch process, for example. In block 210, a radiation (light, X-rays, etc.) blocking material may be formed around the array of fibers. In block 212, a functional material may be deposited on an upper portion of the optical fibers. The functional material may include a phosphorescent or luminescent material and/or an affinity probe (e.g., a target-specific affinity probe). Other functional materials are also contemplated.
In interpreting the appended claims, it should be understood that:
Having described preferred embodiments for an optical faceplate and method of manufacture (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments of the disclosure disclosed which are within the scope and spirit of the embodiments disclosed herein as outlined by the appended claims. Having thus described the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.