Fiberoptic line-of-light illuminating device and lighting system

Abstract: A fiberoptic line-of-light illuminating device includes a fiberoptic able (12) providing a plurality of optical fiber bundles (14), a housing (16) including a block (26) which encapsulates output ends (14A) of the optical fibers in splayed-out in a row, and an elongated single thin aperture (18) defined by the housing in alignment with output ends (14A) of the optical fibers (14) for receiving light emitted from the optical fibers and passing the light in the pattern of a thin line. The device also includes a single optical lens (20), which may be a cylindrical lens or a modified cylindrical lens having different lens shapes formed into the surface thereof, mounted in a transverse cylindrical cavity in the housing (16) in parallel relation to the single aperture and transverse relation to the output ends of the optical fibers for receiving light emitted from the optical fibers (14) and passed through the aperture (18). The lens (20) focuses the light in a desired pattern and may be rotated to clean the lens and/or adjust the bean pattern.

Description: The present invention relates generally to fiberoptic lighting systems and, more particularly, to a fiberoptic line-of-light illuminating device, such as a headlamp, employing a plurality of optical fibers for emitting output light, a single elongated aperture for passing a thin line of output light, and a single cylindrical lens for receiving and focusing the output light. It is well known in the field of fiberoptics that optical fibers are capable of effectively and efficiently conducting light from a common source along nonlinear paths to various locations remote from the light source without encountering substantial transmission losses. Because of this capability, there is increasing interest in the application of optical fibers to uses where space is restricted. One such use is the overall illumination needs of vehicles where space is scarce due to aerodynamic and styling considerations. US-A-4677531 discloses a fiberoptic illuminating device comprising a plurality of optical fibers having output ends for emitting light, a single elongated aperture aligned with said output ends of the optical fibers for receiving light emitted from the optical fibers, a lens having a flat inner surface and convex outer surface, aligned with the aperture for receiving light passing through the aperture and focusing the light. The lens possesses a finite focus and the resulting pattern of illumination is such that one dimension of such pattern, the height, is maintained essentially constant over a wide depth of field. One general approach to the application of optical fibers to vehicular illumination needs is proposed in US-A-4,811,172 to Davenport et al., US-A-4,868,718 to Davenport et al., US-A-4,949,227 to Finch et al., and US-A-4,958,263 to Davenport et al., all assigned to General Electric Company. These patents disclose various lighting systems that basically employ a plurality of optical fibers having their respective input ends coupled to a high intensity common light source and their respective output ends individually coupled to respective ones of a plurality of paired apertures and optical lenses. Thus, the operative principle underlying this approach is to use one lens and one aperture per optical fiber. An illuminating device constructed in accordance with the operative principle of the cited prior art patents will have a total length which is at least equal to the combined lengths of the individual lenses used in the device. For instance, where each lens is a spherical Fresnel lens of about 6,45 cm 2 (one inch square), an illuminating device having nine optical fibers under the prior art approach is at least about 22,9 cm (nine inches) in length. The lenses taken together add excessive length to the device. While this general approach may fulfill overall illumination requirements, a major shortcoming is that it fails to accommodate space limitations dictated by vehicular aerodynamic and styling requirements. The provision of one lens and one aperture per optical fiber results in devices much too large to find general application to all locations where illumination is required in vehicles. Thus, there is a need for a fiberoptic illuminating device that will satisfy the overall illumination requirements of vehicles while avoiding the aforementioned major shortcoming. This need is met by the fiberoptic line-of-light illuminating device of the present invention. The operative principle underlying the present invention is to use a single optical lens which is preferably a cylindrical or a modified cylindrical one and a thin line of splayed output ends of all optical fibers of the illuminating device. According to the present invention, there is provided fiberoptic line-of-light illuminating device, comprising: means (12) providing a plurality of optical fibers (14) for conducting light, said optical fibers (14) having output ends (14A) for emitting light, a housing (16) having therein a block (26) encapsulating said output ends (14A) of said optical fibers (14) arranged in a splayed-out fashion in a row; said housing (16) defining a single elongated aperture (18) aligned with said output ends (14A) of all of said optical fibers (14) for receiving light emitted from said optical fibers and passing light, said single aperture (18) having a configuration of an elongated thin line; and a single cylindrical optical lens (20) aligned with said single aperture (18) for receiving light emitted from said optical fibers (14) and passed through said aperture (18) and focusing the light in a desired pattern; said housing (16) also defining an elongated cavity (36) containing said lens (20) and spaced forwardly from and extending in transverse relation to said output ends (14A) of said optical fibers (14); and said housing further defining an elongated slot (38) disposed between said single aperture (18) and a rear side of said elongated cavity (36) for providing a passage between said single aperture (18) and said single cylindrical lens (20) to pass light emitted from said optical fibers (14) through said aperture (18) to said lens (20). The cylindrical lens is rotatable within the elongated cavity. Rotatability permits cleaning of all surfaces of the lens. In the most preferred embodiment, the housing body may have a blade, gasket or grommet of an elastomeric (rubber, polymer, foam rubber, polymeric foam, etc.) or other material interfitted therein so that it contacts the lens and wipes it clean during rotation of the lens. The single optical lens may be of a modified cylindrical shape. For example, different lens shapes may be formed into the rear surface of an otherwise cylindrical lens to provide different beam patterns such as high beam, low beam, etc. With such a modified cylindrical shape, the different beam pattern may be selected by indexing the lens to different portions of rotation about its axis. An advantage of the present miniaturised fiberoptic illuminating device in addition to its space saving features, is its ease of assembly and alignment. A single cylindrical lens is easier to assemble, easier to align, and less likely to become unaligned than the one-lens-per optic fiber systems. The invention will now be described further, by way of example, with reference to the accompanying drawings, in which: Fig. 1 is a schematic representation of a fiberoptic line-of-light illuminating device constructed in accordance with the operative principle of the present invention; Fig. 2 is a top plan view of a preferred embodiment of the fiberoptic illuminating device; Fig. 3 is a front elevational view of the fiberoptic illuminating device as seen along line 3--3 of Fig. 2; Fig. 4 is a sectional view of the fiberoptic illuminating device taken along line 4--4 of Fig. 2; and Fig. 5 is a sectional view of the miniaturised fiberoptic illuminating device showing an alternative modified cylindrical lens. Referring to Fig. 1 of the drawings, there is illustrated a schematic representation of a fiberoptic line-of-light illuminating device, generally designated 10, having a construction in accordance with the operative principle of the present invention. While the device 10 of the present invention is generally applicable to a variety of lighting applications, it is particularly suited for use in vehicle forward lighting applications such as high beam and low beam headlamps, driving lights, corner lights and turn signals. A preferred embodiment of the illuminating device 10 in the form of a headlamp is illustrated in Figs. 2-4. Referring now to Figs. 1-4, the fiberoptic line-of-light illuminating device 10 basically includes a large fiberoptic cable 12 providing a plurality of bundles of optical fibers, each containing a large number of individual filaments, hereinafter referred to as optical fibers 14, for conducting and emitting output light, a housing body 16 defining a thin elongated line 18 of splayed output ends of optical fibers 14 for passing a thin line of output light, and a single lens 20 for receiving and focusing the output light in a desired pattern P. The illuminating device 10 is part of a lighting system, indicated by the numeral 22, which has a light source 24 coupled in a well-known conventional way to input ends of the optical fibers 14 of the large fiberoptic cable 12. Any suitable light source 24 can be utilised. The housing body 16 has a single aperture 18 and includes a block 26 and a pair of opposite side strips 28 being secured to opposite sides of the block 26 by suitable means, such as pairs of threaded fasteners 30. One of the side strips 28 has an opening 32 surrounded by a connector 34 which couples with the large fiberoptic cable 12. Leading portions of the optical fibers 14 emerge from the large fiberoptic cable 12 through the side strip 28 and into the housing body 16 where they may be encapsulated in the block 26. The encapsulated optical fibers 14 at their output ends 14A are arranged in splayed out fashion in a row the width of single aperture 18. Thus, as shown in Fig. 2 there are nine optical fibers 14, each of which is a bundle of a large number of individual filaments on the order of 0.005 cm (0.002 inches) in diameter. Optical fibers 14 are spaced within block 26 and at the output ends 14A are further splayed into a stack of 5-10 layers of filaments 0.05 to 0.1 cm (0.02 to 0.04 inches) thick. Such a splay will result in a fiberoptic ribbon the width of aperture 18. Block 26 may be an acrylic or epoxy material which will encapsulate optical fibers 14. A rectangular opening the size of aperture 18 is cut and polished into block 26, exposing the output ends 14A of optical fibers 14. The output ends 14A are wetted with a wetting agent such as isopropyl alcohol and a jacket 19 with aperture 18 formed therein is overlayed and the remainder of housing body 16 joined to block 26 by suitable means, such as pairs of threaded fasteners (not shown) similar to threaded fasteners 30. The aperture 18 receives light emitted from the optical fibers 14 and passes the light toward the single cylindrical lens 20. The aperture 18 has a configuration of a long thin line for passing an elongated thin-line pattern of light. The housing body 16 also has a single cylindrical cavity 36 spaced forwardly of the thin elongated line 18. The cylindrical cavity 36 contains the single cylindrical lens 20 and extends in transverse relation to the output ends 14A of the optical fibers 14 and parallel relation to the thin elongated line 18. The construction of the housing body 16 thus ensures alignment of central axes "A" of the end portions 14A of the optical fibers 14 in generally parallel relation with each other and generally perpendicular intersecting relation with a central axis "B" of the cylindrical lens 20. The housing body 16 further has an elongated slot 38 located between the thin elongated line 18 and the rear side of the transverse cavity 36. The slot 38 which communicates the thin elongated line 18 with the rear side of the transverse cavity 36 provides a passage from the thin elongated line 18 to the cylindrical lens 20 to pass light emitted from the optical fibers 14 in the pattern of the thin line through the slot 38 to the lens 20. Slot 38 spaces the output ends 14A of optical fibers 14 from the lens 20 at a distance which is approximately the focal length of lens 20. The housing body 16 also defines a substantially semi-cylindrical opening 40 along a front end intersecting with a front side of the transverse cavity 36 for permitting light focussed by the lens 20 in the desired pattern P to pass from the housing body 16. As shown in Fig. 4, there is fitted in housing body 16 a blade, gasket or grommet 42 which may be an elastomeric material such as rubber, polymer, foam rubber, polymeric foam, etc. which will wipe clean cylindrical optical lens 20 when lens 20 is rotated within cavity 36. Thus, as shown in Fig. 2, a motor 44, such as a stepper motor, may be attached to lens 20 for rotation of lens 20 around central axis B. By periodically rotating lens 20 around central axis B, the exterior, light receiving/transmitting surfaces of cylindrical optical lens 20 may be cleaned. Blade, gasket or grommet 42 may be made replaceable so that a fresh one can be inserted when the old one becomes soiled. The forward end portions of the side strips 28 of the housing 16 close the opposite ends of the transverse cavity 36. Either one of the side strips 28 can be detached from the housing body 26 in order to remove the cylindrical lens 20 from the housing 16. Thus, the single elongated thin aperture 18 receives light emitted from the optical fibers 14 and passes a thin line of light through the elongated slot 38 to the single cylindrical lens 20. The cylindrical lens 20 then collimates the emergent light in the vertical direction and focuses the light in the desired pattern P. A practical example of some of the dimensions of the illuminating device 10 are as follows. In a rectangular configuration, the single aperture 18 have a height in the range of from 0.05 to 0.1 cm (0.020 to 0.040 inch). The cylindrical lens 16 is 1.25 cm (1/2 inch) in height and 8.9 cms (3 1/2 inches) in length with a 1.0 cm (0.4 inch) focal length. Referring to Fig. 5, where like reference numerals have been used to the extent possible, there is shown a modified cylindrical lens 20' which is formed from a cylindrical one, but has lens shapes 46, 48 formed therein. The beam pattern, such as high beam, low beam, fog light, etc., can be selected by rotating the lens so that lens shape 46, lens shape 48, or an unshaped area of lens 20' is aligned with the thin elongated line 18 in order to focus light from opening 40 in the desired pattern.

Claims: A fiberoptic line-of-light illuminating device, comprising: means (12) providing a plurality of optical fibers (14) for conducting light, said optical fibers (14) having output ends (14A) for emitting light, a housing (16) having therein a block (26) encapsulating said output ends (14A) of said optical fibers (14) arranged in a splayed-out fashion in a row; said housing (16) defining a single elongated aperture (18) aligned with said output ends (14A) of all of said optical fibers (14) for receiving light emitted from said optical fibers and passing light, said single aperture (18) having a configuration of an elongated thin line; and a single cylindrical optical lens (20) aligned with said single aperture (18) for receiving light emitted from said optical fibers (14) and passed through said aperture (18) and focusing the light in a desired pattern; said housing (16) also defining an elongated cavity (36) containing said lens (20) and spaced forwardly from and extending in transverse relation to said output ends (14A) of said optical fibers (14); and said housing further defining an elongated slot (38) disposed between said single aperture (18) and a rear side of said elongated cavity (36) for providing a passage between said single aperture (18) and said single cylindrical lens (20) to pass light emitted from said optical fibers (14) through said aperture (18) to said lens (20). A device according to claim 1, wherein said lens is a modified cylindrical lens (20) having different lens shapes (46,48) formed into the surface thereof. A device according to claims 1 or 2, further including a means (44) to rotate said lens (20) about its axis within said elongated cavity (36). A device according to claim 3, wherein said housing (16) includes a gasket or grommet (42) therein which is in contact with said cylindrical lens (20). A lighting system, comprising a source of light (24) and a device claimed in anyone of the preceding claims said optical fibers (14) being coupled to said light source (24) for receiving light.

Inventors: WINDROSS GENE RHEN, WINDROSS, GENE RHEN
Applicants: FORD FRANCE, FORD MOTOR CO, FORD WERKE AG, FORD FRANCE S. A., FORD MOTOR COMPANY LIMITED, FORD-WERKE AKTIENGESELLSCHAFT
Application year: 1992
Main classification: B60Q1
IPC codes: B60Q1, F21V8, F21V14, F21S8