Illumination fiber optic ribbon
An illumination fiber optic ribbon includes optically-transmissive fibers which are adjacent to each other. At least two of the optically-transmissive fibers are twisted together to form a twisted segment. Where the two optically-transmissive fibers are not twisted forms a non-twisted segment. The twisted segments and non-twisted segments alternate along the length of the ribbon. Bends are disposed along the twisted segment and are formed by twisting adjacent optically-transmissive fibers. A light source is connected to one or both end of the optically-transmissive fibers. The light source emits a light flux into the ribbon so that light emits from the bends in the twisted segment.
This application is a continuation in part of U.S. patent application Ser. No. 11/698,101, entitled “Illumination Fiber Optic Ribbon,” by Carl Booth et al., filed Jan. 26, 2007, the disclosure of which is incorporated herein by reference in its entirety.
FIELD OF THE INVENTIONThe present invention relates to fiber optic cables used for illumination. In particular, the present invention relates to an illumination fiber optic ribbon with alternating twisted segments from which light is emitted and non-twisted segments for better connection to a light source.
BACKGROUND OF THE INVENTIONFiber optic cable is often used to transmit light in the longitudinal direction of the cable from one end of the cable to the other end. Fiber optic cables can also be made to transmit light radially away. Such radial light transmission is often used for area lighting, such as around swimming pools, walkways, signs, safety lighting, or decorative accent lighting. Fiber optic cables are often used instead of electrical cables because fiber optic cables require only one light source and the light source's electrical power can be at a distant location.
Such fiber optic cables use special methods of manufacture, such as inclusion of actinically-sensitive dyes or other light-scattering materials to enhance the radial transmission of light. Other approaches avoid special manufacturing methods by bundling a large number of individual fibers together or by bundling groups of wound fibers together. The bundling is not cost efficient and wastes emitted light since light from central fibers is blocked by outer fibers.
Additionally, known fiber optic cables do not provide a simple and efficient mechanism for connecting the fibers to a light source so that the maximum amount of light is sent into the cable and not reflected back to the light source or refracted away from the cable. Cable installers must unwind the cable and laboriously connect individual fibers to the light source. Additionally, known cables do not provide an efficient way to sever the cable to a desired length and then provide a labor-saving way to connect the severed end to a light source so that the maximum amount of light is accepted into the cable.
SUMMARY OF THE INVENTIONAccordingly, it is an aspect of the invention to provide an illumination fiber optic ribbon with alternating twisted segments from which light is emitted and non-twisted segments for optimal connection to a light source. The ribbon can be severed at one of the non-twisted segments and still provide optimal connection to the light source.
One embodiment of the present invention provides an illumination fiber optic ribbon. The ribbon includes optically-transmissive fibers disposed adjacent to each other, at least two of the optically-transmissive fibers being twisted together to form a twisted segment and the at least two optically-transmissive fibers being parallel to one another to form a non-twisted segment, the twisted and non-twisted segments alternating along a length of the ribbon; bends disposed along said twisted segments, the bends formed by the twisting of adjacent optically-transmissive fibers; and at least one of the non-twisted segments being capable of connection to a light source disposed at one or both ends of the optically-transmissive fibers, the light source emitting a light flux into the twisted and non-twisted segments of the optically-transmissive fibers so that light therefrom is emitted from the bends along the twisted segments.
Another embodiment of the present invention provides an illumination fiber optic ribbon. The ribbon includes optically-transmissive fibers disposed adjacent to each other, at least two of the optically-transmissive fibers being twisted together to form a twisted segment and the at least two optically-transmissive fibers being parallel to one another to form a non-twisted segment, the twisted and non-twisted segments alternating along a length of said ribbon; bends disposed along the twisted segments, the bends formed by the twisting of adjacent optically-transmissive fibers; at least one of the non-twisted segments being capable of connection to a light source disposed at one or both ends of said plurality of optically-transmissive fibers, the light source emitting a light flux into the twisted and non-twisted segments of the optically-transmissive fibers so that light therefrom is emitted from the bends along the twisted segments; and a sheath substantially enclosing the optically-transmissive fibers.
Yet another embodiment of the present invention provides a method of manufacturing an illumination fiber optic ribbon. The method of manufacturing includes the steps of: disposing a plurality of optically-transmissive fibers adjacent to one another; twisting adjacent optically-transmissive fibers in a portion of a length of the ribbon to form a twisted segment; forming a plurality of bends at a cladding on each of said plurality of optically-transmissive fibers by the twisting; providing a non-twisted segment in a portion of the length of the ribbon in which adjacent optically-transmissive fibers are not twisted; and alternating the non-twisted segments with the twisted segments.
Yet another embodiment of the present invention provides an illumination fiber optic ribbon. The illumination fiber optic ribbon includes optically-transmissive fibers disposed adjacent to each other, at least two of the plurality of optically-transmissive fibers being twisted together to form a twisted segment and the at least two optically-transmissive fibers being parallel to one another to form a non-twisted segment, the twisted and non-twisted segments alternating along a length of the ribbon; bends along the twisted segment formed by the twisting of adjacent optically-transmissive fibers, the bends per unit length increasing as the length of the ribbon increases; and at least one of the non-twisted segments being capable of connection to a light source disposed at one or both ends of the optically-transmissive fibers, the light source emitting a light flux into the twisted and non-twisted segments of optically-transmissive fibers so that light therefrom is emitted from the bends along the twisted segments.
Other objects, advantages and salient features of the invention will become apparent from the following detailed description, which, taken in conjunction with the annexed drawings, discloses a preferred embodiment of the present invention.
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
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In the twisted segments 104a and 104b of the ribbon 100, the twisting of the optically-transmissive fibers 102 causes bends 116 in the cladding 202 of the individual fibers 102. Due to the bends 116 in the cladding 202, the index of refraction of the cladding 202 is altered. The change in the index of refraction of the cladding 202 affects a critical angle of light or the angle at which the light 208 can be directed back to the core 204. The change in the critical angle of light allows the light 208 to emit through the bend 116. In alternate embodiments, the change in the index of refraction of the cladding 202 may be caused by distortions in the cladding 202 instead of by bending the cladding 202. The distortions in the cladding 202 may be caused chemically or mechanically. The cladding 202 may also be disrupted to allow light 208 to emit.
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The ribbon 100 includes alternating twisted segments, such as segments 104a and 104b, and non-twisted segments, such as segments 106a, 106b, and 106c. The twisted segments 104a and 104b include at least two adjacent optically-transmissive fibers 102 twisted together. Preferably, all of the optically-transmissive fibers 102 are twisted into pairs at the twisted segments 104a and 104b. Portions where the adjacent optically-transmissive fibers 102 are not intertwined, that is parallel, form the non-twisted segments 106a-106c which may alternate with the twisted segments 104a and 104b. Although only two twisted segments 104a and 104b and three non-twisted segments 106a-106c are illustrated, the ribbon 100 may have more than two twisted segments 104a and 104b and more than three non-twisted segments 106a-106c, or only a single twisted segment and single non-twisted segment. Preferably, at least one non-twisted segment, such as 106a or 106c, is disposed at one or both ends of the ribbon 100 to facilitate connection to a light source 302. The light source 302 provides light. It may be an electrically-powered light source, a solar-powered light source, or a natural light source.
The light 208 provided by the light source 302 can attenuate as the length of the ribbon 100 increases. However, in certain applications, the attenuation in light 208 may be undesirable. Thus, to compensate for the attenuation in the light emitted from the ribbon 100 as its length increases, the bends 116 per unit length of the ribbon 100 can be increased as the length of the ribbon 100 increases. As described above, the twisting of optically-transmissive fibers 102 causes bends 116 in the cladding 202 of each fiber 102, and the bends 116 allow light 208 to be emitted. Accordingly, by increasing the twisting of optically-transmissive fibers 102, the number of bends 116 per unit length of the ribbon 100 can be increased which allows more light 208 to be emitted from the ribbon 100. Referring to
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The optimum acceptance angle 402 is determined by a numerical aperture of the optically-transmissive fiber 424. The numerical aperture is a value that can be readily found by one skilled in the art for a particular optically-transmissive fiber 424. The numerical aperture is defined as the square-root of the difference of the squares of the index of refraction for the core and the index of refraction for the cladding or √(index of refraction of the core)2−(index of refraction of the cladding)2. The numerical aperture is also the sine of the optimum acceptance angle 402 or sine (optimum acceptance angle 402). Therefore, to find the optimum acceptance angle 402 for a particular optically-transmissive fiber 424, find the inverse sine or arcsine of the numerical aperture, a value readily obtained for a particular optically-transmissive fiber 424. The optimum acceptance angle 402 derived from the numerical aperture is relative to the longitudinal axis 416 of the optically-transmissive fiber 424.
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Substantially all of the optically-transmissive fibers 102 in the non-twisted segments, such as end segment 106a, can be simultaneously positioned since all the optically-transmissive fibers 102 are coupled to the sheath 110. That way, all of the fibers 102 of the non-twisted segment 106a may be positioned for light to enter at the optimum acceptance angle of the optically-transmissive fibers 102 to facilitate connection of the fibers 102 to the light source 302.
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A method for manufacturing the illumination fiber optic ribbon 100 begins with placing optically-transmissive fibers 102 adjacent to one another in generally the same plane. As described previously, the number of optically-transmissive fibers 102 can be varied in order to achieve the required size. Next, adjacent optically transmissive-fibers 102 are twisted for a predetermined portion of their respective lengths to form at least one twisted segment 104a or 104b. By twisting the adjacent optically-transmissive fibers 102 into pairs, bends 116 are formed from which light is emitted. In alternate embodiments, the cladding 202 may be distorted mechanically, chemically, or by other similar processes that affect the index of refraction of the cladding 202. The cladding 202 may also be disrupted to allow light emission. Next, non-twisted segments 106a, 106b, and 106c are provided where the optically-transmissive fibers 102 are not twisted. Next, the twisted segments 104a and 104b and non-twisted segments 106a-106c are alternated. Finally, the number of bends 116 per unit length may be increased as the length of the ribbon 100 increases. As discussed above, increasing the number of bends 116 per unit length can compensate for the attenuation of light as the length of the ribbon 100 increases. By providing more bends 116 per unit length, more light can be emitted from the ribbon 100.
The sheath 110 may be coupled to both the twisted segments 104a and 104b and non-twisted segments 106a-106c. Alternatively, the sheath 110 may be coupled only to the twisted segments 104a and 104b. The light source 302 can be disposed at one end of the optically-transmissive fibers 102 and coupled to a non-twisted segment 106a. A second light source (not shown) may be coupled to the opposite end of the ribbon 100 such as at segment 106c. Corona etching the plurality of optically-transmissive fibers 102 may be done prior to coupling the optically-transmissive fibers 102 to the sheath 110, preferably before placing optically-transmissive fibers 102 adjacent to one another.
As apparent from the above description, the present invention provides an illumination fiber optic ribbon. Optically-transmissive fibers are placed adjacent to each other to form a generally flat ribbon. Twisting adjacent optically-transmissive fibers forms twisted segments which alternate with non-twisted segments where adjacent optically-transmissive fibers are not twisted. The twisting of adjacent-optically transmissive fibers forms bends from which light is emitted. The number of bends may increase as the length of the ribbon increases. A sheath may substantially surround the optically-transmissive fibers.
Accordingly, when a light source is coupled to one end of the optically-transmissive fibers, the light source emits a light flux into one end of the optically-transmissive fibers. The light flux then emanates from the bends to provide illumination.
While particular embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes and modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
Claims
1. An illumination fiber optic ribbon, comprising of:
- a plurality of optically-transmissive fibers disposed adjacent to each other, at least two of said plurality of optically-transmissive fibers being twisted together to form a twisted segment and said at least two optically-transmissive fibers being parallel to one another to form a non-twisted segment, said twisted and non-twisted segments alternating along a length of said ribbon;
- a plurality of bends disposed along said twisted segments, the plurality of bends formed by the twisting of adjacent optically-transmissive fibers; and
- at least one of said non-twisted segments being capable of connection to a light source disposed at one or both ends of said plurality of optically-transmissive fibers, said light source emitting a light flux into said twisted and non-twisted segments of said plurality of optically-transmissive fibers so that light therefrom is emitted from said plurality of bends along said twisted segments.
2. An illumination fiber optic ribbon according to claim 1, wherein each of said plurality of optically-transmissive fibers includes
- a core of optically-transparent material having a first index of refraction; and
- a cladding surrounding said core, said cladding having a second index of refraction different than said first index of refraction of said core.
3. An illumination fiber optic ribbon according to claim 2, wherein said plurality of bends change the second index of refraction so that a light ray in said core can emit through said cladding.
4. An illumination fiber optic ribbon according to claim 2, wherein the second index of refraction is distorted chemically or mechanically so that a light ray in said core can emit through said cladding.
5. An illumination fiber optic ribbon according to claim 2, wherein said cladding is disrupted so that a light ray in said core can emit through said cladding.
6. An illumination fiber optic ribbon according to claim 1, further comprising of a sheath substantially enclosing said plurality of optically-transmissive fibers.
7. An illumination fiber optic ribbon according to claim 6, wherein said sheath is coupled to said plurality of optically-transmissive fibers.
8. An illumination fiber optic ribbon according to claim 7, wherein said sheath is coupled only to said twisted segments by an adhesive film.
9. An illumination fiber optic ribbon according to claim 7, wherein said coupling is by an adhesive film, said adhesive film disposed on an inner surface of said sheath.
10. An illumination fiber optic ribbon according to claim 9, wherein said adhesive film is a polyester adhesive.
11. An illumination fiber optic ribbon according to claim 6, wherein said sheath is substantially transparent.
12. An illumination fiber optic ribbon according to claim 6, wherein a portion of said sheath is opaque.
13. An illumination fiber optic ribbon according to claim 6, wherein a portion of said sheath is formed of reflective material.
14. An illumination fiber optic ribbon according to claim 1, wherein said light source is an electrically-powered light source, a solar-powered light source, or a natural light source.
15. An illumination fiber optic ribbon according to claim 1, wherein said plurality of bends per unit length increases as said length of said ribbon increases.
16. An illumination fiber optic ribbon, comprising of:
- a plurality of optically-transmissive fibers disposed adjacent to each other, at least two of said plurality of optically-transmissive fibers being twisted together to form a twisted segment and said at least two optically-transmissive fibers being parallel to one another to form a non-twisted segment, said twisted and non-twisted segments alternating along a length of said ribbon;
- a plurality of bends disposed along said twisted segments, the plurality of bends formed by the twisting of adjacent optically-transmissive fibers;
- at least one of said non-twisted segments being capable of connection to a light source disposed at one or both ends of said plurality of optically-transmissive fibers, said light source emitting a light flux into said twisted and non-twisted segments of said plurality of optically-transmissive fibers so that light therefrom is emitted from said plurality of bends along said twisted segments; and
- a sheath substantially enclosing said plurality of optically-transmissive fibers.
17. An illumination fiber optic ribbon according to claim 16, wherein each of said plurality of optically-transmissive fibers includes
- a core of optically-transparent material having a first index of refraction; and
- a cladding surrounding said core, said cladding having a second index of refraction different than said first index of refraction of said core.
18. An illumination fiber optic ribbon according to claim 17, wherein said plurality of bends change the second index of refraction so that a light ray in said core can emit through said cladding.
19. An illumination fiber optic ribbon according to claim 17, wherein the second index of refraction is distorted chemically or mechanically so that a light ray in said core can emit through said cladding.
20. An illumination fiber optic ribbon according to claim 17, wherein said cladding is disrupted so that a light ray in said core can emit through said cladding.
21. An illumination fiber optic ribbon according to claim 16, wherein said sheath is coupled to said plurality of optically-transmissive fibers.
22. An illumination fiber optic ribbon according to claim 21, wherein said sheath is coupled only to said twisted segments.
23. An illumination fiber optic ribbon according to claim 21, wherein said coupling is by an adhesive film, said adhesive film disposed on an inner surface of said sheath.
24. An illumination fiber optic ribbon according to claim 23, wherein said adhesive film is a polyester adhesive.
25. An illumination fiber optic ribbon according to claim 16, wherein said sheath is substantially transparent.
26. An illumination fiber optic ribbon according to claim 16, wherein a portion of said sheath is opaque.
27. An illumination fiber optic ribbon according to claim 16, wherein a portion of said sheath is formed of reflective material.
28. An illumination fiber optic ribbon according to claim 16, wherein said light source is an electrically-powered light source, a solar-powered light source, or a natural light source.
29. An illumination fiber optic ribbon according to claim 17, wherein said plurality of bends per unit length increases as said length of said ribbon increases.
30. A method of manufacturing an illumination fiber optic ribbon, comprising the steps of:
- disposing a plurality of optically-transmissive fibers adjacent to one another;
- twisting adjacent optically-transmissive fibers in a portion of a length of the ribbon to form a twisted segment;
- forming a plurality of bends at a cladding on each of said plurality of optically-transmissive fibers by the twisting;
- providing a non-twisted segment in a portion of the length of the ribbon in which adjacent optically-transmissive fibers are not twisted; and
- alternating the non-twisted segments with the twisted segments.
31. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of coupling the plurality of optically-transmissive fibers to a sheath.
32. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of coupling only the twisted segments to a sheath.
33. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of disposing a light source at one or both ends of the plurality of optically-transmissive fibers, the light source emitting a light flux into the end of the plurality of optically-transmissive fibers.
34. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of corona etching the plurality of optically-transmissive fibers prior to coupling the optically-transmissive fibers to the sheath.
35. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of distorting the cladding chemically or mechanically so that a light ray can emit through the cladding.
36. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of disrupting the cladding so that a light ray can emit through the cladding.
37. A method of manufacturing an illumination fiber optic ribbon according to claim 30, further comprising the step of increasing the plurality of bends per unit length as the length of the ribbon increases.
38. An illumination fiber optic ribbon, comprising:
- a plurality of optically-transmissive fibers disposed adjacent to each other, at least two of said plurality of optically-transmissive fibers being twisted together to form a twisted segment and said at least two optically-transmissive fibers being parallel to one another to form a non-twisted segment, said twisted and non-twisted segments alternating along a length of said ribbon;
- a plurality of bends along said twisted segment formed by the twisting of adjacent optically-transmissive fibers, said plurality of bends per unit length increasing as said length of said ribbon increases; and
- at least one of said non-twisted segments being capable of connection to a light source disposed at one or both ends of the plurality of optically-transmissive fibers, said light source emitting a light flux into said twisted and non-twisted segments of said plurality of optically-transmissive fibers so that light therefrom is emitted from said plurality of bends along the twisted segments.
39. An illumination fiber optic ribbon according to claim 38, wherein each of said plurality of optically-transmissive fibers includes
- a core of optically-transparent material having a first index of refraction; and
- a cladding surrounding said core, said cladding having a second index of refraction different than said first index of refraction of said core.
40. An illumination fiber optic ribbon according to claim 39, wherein said plurality of bends change the second index of refraction so that a light ray in said core can emit through said cladding.
41. An illumination fiber optic ribbon according to claim 39, wherein the second index of refraction is distorted chemically or mechanically so that a light ray in said core can emit through said cladding.
42. An illumination fiber optic ribbon according to claim 39, wherein said cladding is disrupted so that a light ray in said core can emit through said cladding.
43. An illumination fiber optic ribbon according to claim 38, further comprising of a sheath substantially enclosing said plurality of optically-transmissive fibers.
44. An illumination fiber optic ribbon according to claim 43, wherein said sheath is coupled to said plurality of optically-transmissive fibers.
45. An illumination fiber optic ribbon according to claim 44, wherein said sheath is coupled only to said twisted segments by an adhesive film.
46. An illumination fiber optic ribbon according to claim 44, wherein said coupling is by an adhesive film, said adhesive film disposed on an inner surface of said sheath.
47. An illumination fiber optic ribbon according to claim 46, wherein said adhesive film is a polyester adhesive.
48. An illumination fiber optic ribbon according to claim 43, wherein said sheath is substantially transparent.
49. An illumination fiber optic ribbon according to claim 43, wherein a portion of said sheath is opaque.
50. An illumination fiber optic ribbon according to claim 43, wherein a portion of said sheath is formed of reflective material.
51. An illumination fiber optic ribbon according to claim 38, wherein said light source is an electrically-powered light source, a solar-powered light source, or a natural light source.
Type: Application
Filed: Sep 26, 2007
Publication Date: Jul 31, 2008
Inventors: Carl Stephen Booth (Storrs, CT), Albert Michael Ermer (Seymour, CT), Gregory Raymond Fitts (Hamden, CT), Mark Wayne Grover (Portland, CT), William Hunt Pendleton (Cheshire, CT)
Application Number: 11/902,833
International Classification: F21V 8/00 (20060101);