Abstract:
Disclosed are devices, systems, and methods for construction or fabrication of optical fiber-like devices by depositing curable optical materials of differing indices of refraction in a controlled manner forming integral optical pathways, the integral optical pathways exhibiting total internal reflection and functioning essentially equivalent optical properties to conventional optical fibers optical pathways.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/998,400, filed Jun. 27, 2014, which is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present invention is generally related to construction or fabrication of optical devices, and more particularly, the present invention discloses methods of constructing or fabricating optical pathways as integral parts of a device structure that has essentially equivalent optical properties to conventional optical fibers. 
       BACKGROUND 
       [0003]    In the field of optics and especially optical imaging, a number of devices are found, including, but not limited to, Fiber Optic Faceplates and Fiber Optic Tapers, that are historically constructed by combining a plurality of discrete optical fibers. Optical fibers are typically cylindrical strands of glass or optical polymer with an index of refraction of n 1 , sheathed or clad with a thin layer of a second glass or polymer with an index of refraction of n 2 , where n 2  is less than n 1 , thereby enabling the well-known phenomenon of Total Internal Reflection. 
         [0004]    Fiber Optic Taper and Fiber Optic Faceplates are currently and typically constructed as follows:
       1. A usually large number of discrete optical fibers are gathered into a bundle (usually round) and heated to the softening point of the cladding material while circumferential pressure is applied to the bundle, causing the fibers to fuse together.
           a. In the case of a fiber optic faceplate, the fused bundle is then sliced into disks of desired thickness.
               i. The faces of the disks are ground and polished and the faceplate is trimmed to the desired final size and shape.   
               b. In the case of a fiber optic taper, the bundle is heated to the softening point of the material and the bundle is longitudinally stretched so that the diameter necks down between the ends.
               i. The tapered shape is then sliced at the neck and the ends, creating two fiber optic tapers.   
               c. As with the fiber optic faceplate, the ends are then ground and polished.   
               
 
         [0011]    Thus it is seen that the current process requires potentially expensive and complex equipment to handle large bundles of thin, fragile fibers, provide controlled high-temperature compression and drawing, and perform slicing operations. 
         [0012]    In view of this, it would be desirable to develop a method or methods of constructing or fabricating optical pathways as integral parts of a device structure, and that the optical pathways have equivalent optical properties to conventional optical fibers. 
       SUMMARY 
       [0013]    The current Invention is a dramatic and innovative improvement to the methods of construction and fabrication of fiber optic devices in the current art. 
         [0014]    In one aspect, the invention is a method of fabricating an optical fiber-like device by depositing curable optical materials of differing indices of refraction in a controlled manner forming integral optical pathways, the pathways exhibiting total internal reflection and functioning as optical fibers. 
         [0015]    In many embodiments, depositing curable optical materials in a controlled manner includes depositing multiple layers of discrete deposits of first and second curable optical materials between a bottom surface or face and a top surface or face forming integral optical pathways of the first material surrounded by the second material, the second material having a lower index of refraction than the first material. 
         [0016]    In many embodiments, depositing multiple layers of discrete deposits of first and second curable optical materials includes depositing the first and second materials on the corresponding first and second material deposits of the previous layer. 
         [0017]    In many embodiments, depositing multiple layers of discrete deposits of first and second curable optical materials includes curing each layer of first and second materials prior to depositing a subsequent layer. 
         [0018]    In many embodiments, curing each layer of first and second materials includes exposure to UV light. 
         [0019]    In many embodiments, depositing multiple layers of discrete deposits of first and second curable optical materials includes depositing the first and second materials using first and second dispensing heads. 
         [0020]    In many embodiments, the first and second dispensing heads are the same head. 
         [0021]    In many embodiments, the first and second dispensing heads are computer controlled. 
         [0022]    In many embodiments, the device is tapered between the bottom and top surfaces or faces by reducing each subsequent layer in area and material deposit size at a rate of taper desired. 
         [0023]    In many embodiments, the first and second materials are selected from the group consisting of polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes. 
         [0024]    In another aspect, the invention is a method of fabricating an optical fiber-like device by depositing multiple layers of curable optical materials of differing indices of refraction in a controlled manner on a polished surface of a substrate by: 
         [0025]    creating a first layer of curable optical materials on the substrate by:
       depositing an array pattern of discrete deposits of a first curable liquid optical material on the substrate using one or more first dispensing heads;   curing the first material;   depositing a second curable liquid optical material all the areas surrounding the discrete deposits of the first material on the substrate using one or more second dispensing heads, the second material having a lower index of refraction than the first material;   curing the second material;       
 
         [0030]    creating subsequent layers of curable optical materials by:
       depositing discrete deposits of a first curable liquid optical material on the discrete deposits of the previous layer using one or more first dispensing heads;   curing the first material;   depositing a second curable liquid optical material all the areas surrounding the discrete deposits of the first material using one or more second dispensing heads;   curing the second material; and       
 
         [0035]    repeating the creating subsequent layers of the first and second materials on the previous layer until a desired thickness of the fiber optic device is reached, the last layer creating a top surface or face and the layers of discrete deposits forming integral optical pathways of the first material surrounded by the second material between the substrate and top surface or face. 
         [0036]    In many embodiments, curing the first and second materials include exposure of the first and second materials to UV light. 
         [0037]    In many embodiments, the first and second materials are selected from the group consisting of polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes. 
         [0038]    In many embodiments, the device is tapered between the substrate and top surface or face by reducing each subsequent layer in area and material deposit size at a rate of taper desired. 
         [0039]    In many embodiments, the top surface or face is polished. 
         [0040]    In another aspect, the invention is a method of fabricating an optical fiber-like device by depositing multiple layers of curable optical materials of differing indices of refraction in a controlled manner on a polished surface of a substrate by: 
         [0041]    creating an initial layer of curable optical material on the substrate by:
       depositing an area of second material using one or more second dispensing heads that is equal to the size and shape of a cross-section of the desired optical fiber-like device, perpendicular to desired end faces of the device;   curing the second material;       
 
         [0044]    creating a first layer of curable optical materials on the substrate by:
       depositing multiple lines or columns of a first curable liquid optical material on the substrate using one or more first dispensing heads;   curing the first material;   depositing a second curable liquid optical material all the areas surrounding the line or column of the first material on the substrate using one or more second dispensing heads, the second material having a lower index of refraction than the first material;   curing the second material;       
 
         [0049]    creating subsequent layers of curable optical materials by:
       depositing multiple lines or columns a first curable liquid optical material on the previous layer using one or more first dispensing heads;   curing the first material;   depositing a second curable liquid optical material all the areas surrounding the lines or columns of the first material using one or more second dispensing heads;   curing the second material; and       
 
         [0054]    repeating the creating subsequent layers of the first and second materials on the previous layer until a desired final height of the fiber optic device is reached, the line or columns of first materials forming integral optical pathways of the first material surrounded by the second material between the end faces. 
         [0055]    In many embodiments, curing the first and second materials include exposure of the first and second materials to UV light. 
         [0056]    In many embodiments, the first and second materials are selected from the group consisting of polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes. 
         [0057]    In many embodiments, the device is tapered between the end faces by reducing the cross sectional area of each column of first material to reduce over its length from a large surface or face to a small surface or face. 
         [0058]    In many embodiments, an initial construct is created upon the substrate using one or more second dispensing heads dispensing the second material in a size and shape of which corresponds to the size and shape of one outer surface of the desired taper in a chosen plane. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0059]      FIGS. 1A-1H  show one embodiment of fabricating a fiber optic faceplate. 
           [0060]      FIGS. 2A-2H  show another embodiment of fabricating a fiber optic faceplate. 
           [0061]      FIGS. 3A-3J  show one embodiment of fabricating a Fiber Optic Taper. 
           [0062]      FIGS. 4A-4L  show another embodiment of fabricating a Fiber Optic Taper. 
       
    
    
     DETAILED DESCRIPTION 
       [0063]    Embodiments of the invention will now be described with reference to the figures, wherein like numerals reflect like elements throughout. The terminology used in the description presented herein is not intended to be interpreted in any limited or restrictive way, simply because it is being utilized in conjunction with detailed description of certain specific embodiments of the invention. Furthermore, embodiments of the invention may include several novel features, no single one of which is solely responsible for its desirable attributes or which is essential to practicing the invention described herein. 
         [0064]    The disclosed invention is an innovative method of constructing or fabricating integral optical pathways of optical devices, in contrast to the prior art optical devices that are made up of a multiplicity of discrete optical fibers. The disclosed methods allow construction of optical pathways as integral parts of the optical devices. This allows construction or fabrication of optical devices with optical pathways having essentially equivalent optical properties to conventional optical fibers at a much lower cost. 
         [0065]    While the invention is disclosed in relation to fiber optic faceplates and fiber optic tapers, it can readily be seen that the methods of construction or fabrication described herein are not limited to fiber optic faceplates and fiber optic tapers. Indeed, practically any device historically constructed using conventional optical fibers can be constructed more efficiently and more cost effectively using the methods of the disclosed invention. Additionally, using the methods of the disclosed invention, devices can now be constructed that would have been impossible or impractical using conventional optical fibers. An example of this is a device wherein a bend or curve is desired that is of too small of a radius for an optical fiber, but such limitation does not exist for a line or shape dispensed as a liquid and then cured. 
         [0066]    A fiber optic faceplate is a coherent multi-fiber plate, which acts as a zero-depth window, transferring an image pixel by pixel (fiber by fiber) from one face of the plate to the other. Faceplates are often found in high-end imaging applications bonded to CCD&#39;s, voltage stand-off devices in electron microscopes and cathode ray tubes, and as substrates for phosphors. In some embodiments, the fiber optic faceplate can be as large as 355 mm (14″) square or as small as a few hundred microns across, with depth ranging from more than 100 mm down to 50-100 μm. 
         [0067]    Fiber Optic Faceplate, Method 1 
         [0068]      FIG. 1A  shows one embodiment of a fiber optic faceplate  100  having a height H, width W and depth D.  FIGS. 1B-1H  show one embodiment of fabricating the fiber optic faceplate  100 . To create a fiber optic faceplate, a dispensing head is configured to dispense a curable liquid optical material of known index of refraction (“n 1 ”) upon a substrate  110  having a polished surface. A second dispensing head is configured to dispense a curable liquid optical material of a lower index of refraction (“n 2 ”) than the first material in all the areas surrounding the deposits of n 1  material. The dispensing heads are able to be controllably maneuvered in the x, y and z axes by well-known and conventional means, such as through the use of computer-controlled stepper motors, with dispensing rates similarly controllable. The curable liquid optical material may be any material that can be dispensed from a dispensing heads and cured, such as polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes. 
         [0069]    The process is described below. 
         [0070]    1.  FIGS. 1B-1C  show one or more first dispensing heads  105  dispensing upon a polished substrate surface of substrate  110  a pattern  115  (H×W) of discrete deposits of n 1  material  120  of the number and size(s) desired for the particular faceplate. The number, size and spacing of the deposits n 1  correspond to the number, size and spacing of optical fibers in an equivalent faceplate of traditional optical fiber construction. The deposits n 1  are then cured, such as by exposure to UV light  125 . 
         [0071]    2.  FIGS. 1D-1E  show one or more second dispensing heads  130  dispense n 2  material  135  in all the areas surrounding the deposits of n 1  material  120 , within the established perimeter of the face of the faceplate, dispensed by the first dispensing heads in step  1 . The n 2  material  135  is then cured, such as by exposure to UV light  125 .  FIG. 1E  shows one layer of n 1  material  120  and n 2  material  135 . 
         [0072]    3. The process now repeats, layering upon the previous layers, with the next layer of n 1  material deposits and n 2  material fill directly on top of the previous layer.  FIG. 1F  shows five layers of n 1  material  120  and n 2  material  135 . 
         [0073]    4. The process is repeated until the desired final thickness D of the faceplate is reached, shown in  FIGS. 1G and 1H . The completed faceplate  100  is then removed from the substrate  110 . No polishing is needed on the surface or face  140  that was against the polished substrate surface of the substrate  110 . Little or no polishing is needed on the top surface or face  145 . No cutting of the outer size or shape (w or d) is necessary. 
         [0074]    The result is an array of columns or integral optical pathways  150  of n 1  material surrounded by columns  155  of n 2  material. The integral optical pathways or ‘columns’ of n 1  material act the same as ‘fibers’ do in a conventional fiber optic faceplate. The columns  150  are in fact integrally-created fibers now ‘clad’ in n 2  material. The faceplate is simply ‘printed’ as described and is ready to use. 
         [0075]    It can readily be seen that the method described herein is not restricted to square or rectangular face shapes. Fiber optic faceplates of practically any face shape, including circular, elliptical, rectangular and square, can be created. 
         [0076]    Fiber Optic Faceplate, Method 2 
         [0077]      FIG. 2A  shows another embodiment of a fiber optic faceplate  200  having a height H, width W and depth D.  FIGS. 2B-2H  show one embodiment of fabricating the fiber optic faceplate  200 . To create a fiber optic faceplate, one or more dispensing heads are configured to dispense curable liquid optical materials, such as a polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes, upon a substrate having a polished surface. A first dispensing head  205  is configured to dispense a first curable liquid optical material of known index of refraction (“n 1 ”) upon the polished surface and a second dispensing head  230  is configured to dispense a second curable liquid optical material, such as a polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes, having a lower index of refraction (“n 2 ”) than the first material in all the areas surrounding the deposits of n 1  material. The dispensing heads are able to be controllably maneuvered in the x, y and z axes by well-known and conventional means, such as through the use of computer-controlled stepper motors, with dispensing rates similarly controllable. 
         [0078]    The process is described below.
       1.  FIG. 2B  shows one or more second dispensing heads  230  dispensing an initial thin layer of n 2  material  235  upon the polished substrate  210 , covering an area  215  (D×W) that is equal to the size and shape of the cross-section, perpendicular to the faces, of the desired faceplate. This layer is then cured, such as by exposure to UV light  225 .   2.  FIGS. 2C-2D  show one or more first dispensing heads  205  dispensing a line or column  250  of n 1  material  220  upon the cured layer of n 2  material  235 , perpendicular to the long dimension of the faceplate cross-section, and of a width and at a spacing equal to the width and spacing of the fibers in a conventional faceplate of the same size. This material is then cured, such as by exposure to UV light  225 .  FIG. 2D  shows one layer of n 1  material  220  upon the n 2  material  235 .   3. More n 2  material  235  is then dispensed between and over the n 1  material  220  lines created in step  2 . This material is then cured.   4. The process now repeats, layering upon the previous layers.  FIGS. 2E and 2F  show four layers of n 1  material  220  and n 2  material  235 .   5. The process is repeated until the desired final height h of the faceplate is reached, shown in  FIGS. 2G and 2H .   6. A thin layer of n 2  material  235  is dispensed as the final layer and cured.   7. The completed faceplate  200  is then removed from the substrate  210 . Depending upon the application and level of optical quality desired, the faces  240 ,  245  of the completed faceplate may be optimized by grinding or sanding, and polishing.       
 
         [0086]    The result is an array of columns or integral optical pathways  250  of n 1  material surrounded by columns  255  of n 2  material. The integral optical pathways or ‘columns’ act as the ‘fibers’ do in a conventional fiber optic faceplate. The columns are in fact integrally-created fibers now ‘clad’ in n 2  material. The faceplate is simply ‘printed’ as described and is ready to use. 
         [0087]    It can readily be seen that the method described herein is not restricted to square or rectangular face shapes. Fiber optic faceplates of practically any face shape, including circular, elliptical, rectangular and square, can be created. 
         [0088]    Fiber Optic Taper, Method 1 
         [0089]      FIGS. 3A-3J  show one embodiment of fabricating a Fiber Optic Taper  300  that offers a low-distortion method of magnifying or reducing an image for image transfer applications. The Fiber Optic Taper  300  has a shape with a large end and small end that transmits the image from its input surface or face to its output surface or face, shown in  FIGS. 3A-3C . To create a Fiber Optic Taper, one or more dispensing heads are configured to dispense curable liquid optical materials, such as polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes, upon a substrate  310  having a polished surface. A first dispensing head  305  is configured to dispense a first curable liquid optical material of known index of refraction (“n 1 ”) upon the polished surface and a second dispensing head  330  is configured to dispense a second curable liquid optical material, such as a polymer resins, acrylics(methacrylate), polycarbonates, epoxies, polyesters and urethanes, having a lower index of refraction (“n 2 ”) than the first material in all the areas surrounding the deposits of n 1  material. The dispensing heads are able to be controllably maneuvered in the x, y and z axes by well-known and conventional means, such as through the use of computer-controlled stepper motors, with dispensing rates similarly controllable. 
         [0090]    The fiber optic taper  300  is created using the dispensing arrangement previously described above, as follows:
       1.  FIGS. 3D and 3E  show one or more first dispensing heads  305  dispensing upon a polished substrate surface of substrate  310  a pattern  315  (H×W) of discrete deposits of n 1  material  320  of the number and size(s) desired for the particular faceplate. The number, size and spacing of the deposits n 1  correspond to the number, size and spacing of optical fibers in an equivalent taper of traditional optical fiber construction. The deposits n 1  are then cured, such as by exposure to UV light  325 .   2.  FIGS. 3F and 3G  show one or more second dispensing heads  330  dispense n 2  material  335  in all the areas surrounding the deposits of n 1  material  320 , within the established perimeter of the face of the taper, dispensed by the first dispensing heads in step  1 . The n 2  material  335  is then cured, such as by exposure to UV light  325 .  FIG. 3G  shows one layer of n 1  material  320  and n 2  material  335 .   3. The process now repeats, layering upon the previous layers, with the next layer of n 1  material deposits and n 2  material fill directly on top of the previous layer. Each subsequent layer reducing in area and deposit size at the rate of taper desired.  FIGS. 3H and 3I  show four layers of n 1  material  320  and n 2  material  335  with the taper exaggerated for illustration.   4. The process is repeated until the desired final thickness D and taper is reached, shown in  FIG. 3J . The completed Fiber Optic Taper  300  is then removed from the substrate  310 . No polishing is needed on the surface or face  340  that was against the polished substrate surface of the substrate  310 . Little or no polishing is needed on the top surface or face  345 . No other cutting, finishing or machining operations are necessary.       
 
         [0095]    The result is an array of tapered columns  350  of n 1  material surrounded by columns  355  of n 2  material. The ‘columns’ act as the ‘fibers’ do in a conventional fiber optics. The columns are in fact integrally-created fibers now ‘clad’ in n 2  material. The faceplate is simply ‘printed’ as described and is ready to use. 
         [0096]    It can readily be seen that the method described herein is not restricted to square or rectangular face shapes. Fiber optic tapers of practically any face shape, including circular, elliptical, rectangular and square, can be created. Furthermore, this method allows the large face and small face to be of different shapes or aspect ratios, enabling fiber optic tapering functions such as anamorphic squeeze or other intentional geometric manipulation of the image. 
         [0097]    Fiber Optic Taper, Method 2 
         [0098]      FIGS. 4A-4L  show another embodiment of fabricating a Fiber Optic Taper  400 , similar to Fiber Optic Taper  300 , except in this method the fiber optic taper is created in cross-section, that is, in layers that are primarily perpendicular to the faces of the Taper. The layers can therefore be primarily oriented in the X-Z plane ( FIG. 4D ) or the Y-Z ( FIG. 4E ), whichever is deemed to be advantageous to the particular faceplate being fabricated. 
         [0099]    The method is as follows:
       1. An initial construct is created upon a polished substrate using one or more second dispensing heads  430  dispensing an initial layer of n 2  material  435 , the size and shape  415  of which corresponds to the size and shape of one outer surface of the desired Taper in the chosen plane ( FIGS. 4D and 4E ). This construct is then cured, such as by exposure to UV light  425 .   2.  FIGS. 4F-4H  show one or more first dispensing heads  405  dispensing continuous ‘strings’ or columns  450  from the large face to the small face of n 1  material  420  upon the cured layer of n 2  material  435 . The dispensing rate or speed of dispensing is controlled as each string is dispensed, so that the cross sectional area of each string is made to reduce over its length from the large face to the small face, corresponding to the taper of the fibers in a conventional fiber optic taper. This material is then cured, such as by exposure to UV light  425 .   3. More n 2  material  435  is then dispensed between and over the n 1  material  420  ‘strings’ created in step  2  forming columns  455 . This material is then cured, such as by exposure to UV light  425 .  FIG. 4H  shows one layer of n 1  material  420  and n 2  material  435  upon the initial n 2  material  435  in step  1 .   4. The process now repeats, with each layer comprising a set of strings of n 1  material  420 , cured, followed by a layer of n 2  fill  435 , cured.  FIGS. 4I and 4J  show the large end  440  and small end  445  views of four layers of n 1  material  420  and n 2  material  435 .   5. The process continues until the Taper is complete and thin layer of n 2  material  235  is dispensed as the final layer and cured, shown in  FIGS. 4K and 4L .   6. The completed taper  400  is then removed from the substrate  410 . Depending upon the application and level of optical quality desired, the faces  440 ,  445  of the completed taper may be optimized by grinding or sanding, and polishing.       
 
         [0106]    An advantage of Fiber Optic Taper Method #2 over Fiber Optic Taper Method #1 is that each “fiber” is created by a continuous extrusion of n 1  material so that there are no ‘step’ or layer imperfections in the ‘fibers’ that might be present in Method #1. 
         [0107]    It can readily be seen that the method described herein is not restricted to square or rectangular face shapes. Fiber optic tapers of practically any face shape, including circular, elliptical, rectangular and square, can be created. Furthermore, this method allows the large face and small face to be of different shapes or aspect ratios, enabling fiber optic tapering functions such as anamorphic squeeze or other intentional geometric manipulation of the image. 
         [0108]    Other Fiber Optic Devices 
         [0109]    It can readily be seen that the methods of the Invention are not limited to construction of fiber optic faceplates and fiber optic tapers. Indeed, practically any device historically constructed using conventional optical fibers can be constructed more efficiently and more cost effectively using the methods of the Invention. 
         [0110]    Additionally, using the methods of the Invention, devices can now be constructed that would have been impossible or impractical using conventional optical fibers. An example of this is a device wherein a bend or curve is desired that is of too small of a radius for an optical fiber, but such limitation does not exist for a line or shape dispensed as a liquid and then cured. 
         [0111]    Thus the limitations and shortcomings of the methods of producing the devices in the current art are overcome in the current invention, which provides significant novel improvements, including improvements in range of applications, versatility, manufacturability and cost-effectiveness. 
         [0112]    It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims. In addition, where this application has listed the steps of a method or procedure in a specific order, it may be possible, or even expedient in certain circumstances, to change the order in which some steps are performed, and it is intended that the particular steps of the method or procedure claims set forth herebelow not be construed as being order-specific unless such order specificity is expressly stated in the claim.