Fiberoptic Wide-Angle Illuminating Device

Reference is hereby made to a copending patent application, by the same applicant and assigned to the same assignee, disclosing related subject matter entitled "Fiber-Optic Multi-beam Roadway Illuminating Device", U.S. Ser. No. 811,253, filed Dec. 20, 1991.

The present invention relates generally to fiberoptic lighting systems and, more particularly, to a fiberoptic wide-angle illuminating device.

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.

The application of optical fibers to vehicular illumination needs is proposed in U.S. Pat. No. 4,811,172 to Davenport et al., U.S. Pat. No. 4,868,718 to Davenport et al., U.S. Pat. No. 4,949,227 to Finch et al., and U.S. Pat. No. 4,958,263 to Davenport et al., all assigned to General Electric Company. Different approaches to providing forward illumination patterns for vehicles are disclosed in U.S. Pat. Nos. 4,811,172, 4,868,718 and 4,949,227. U.S. Pat. No. 4,811,172 also discloses an approach to providing rear or taillight illumination for vehicles. An approach to providing a centralized lighting system for aerodynamically styled vehicles which employs a high intensity light source is disclosed in U.S. Pat. No. 4,958,263.

These different approaches to providing forward and rear illumination patterns may fulfill illumination needs of vehicles. However, major shortcomings of these approaches are the excessive size of the illumination device and multiplicity and complexity of parts used by the device. In view of these shortcomings, the devices of the aforementioned patents fail to accommodate space limitations dictated by vehicular aerodynamic and styling requirements. Thus, there is still a need for a fiberoptic illumination device that will satisfy illumination requirements while avoiding these shortcomings.

This need is met by the fiberoptic wide-angle illuminating device of the present invention. The approach of the present invention is to employ a fiberoptic cable containing bundles of optical fibers (each bundle containing a large number of individual filaments) whose output ends are arranged in splayed-out fashion, with a yoke receiving and supporting the optical fibers and defining an arcuate-shaped aperture aligned with and lying in the plane of the splayed optical fibers for receiving and passing light emitted from the optical fibers, and a single wide-angle optical lens which is preferably spherical or cylindrical aligned with the single aperture of the yoke for receiving light emitted from the optical fibers through the aperture and for projecting the light in a desired wide-angle arcuate beam pattern. Thus, it is readily apparent that the approach adopted by the present invention will result in an illuminating device that is substantially smaller in size and reduced in complexity compared to the devices of the previously-cited U.S. patents.

It is thus a feature of the present invention to provide a fiberoptic wide-angle illuminating device using a single spherical or cylindrical optical lens and a single elongated aperture in conjunction with a plurality of optical fibers; to provide the illuminating device where output ends of the plurality of optical fibers are arranged in splayed out fashion in a row; to provide the illuminating device where the single aperture is aligned with the splayed output ends of all optical fibers; and to provide the illuminating device having a yoke with a C-shaped head defining the single aperture in the configuration of an arc such that the light is projected by the lens in an wide-angle arcuate beam pattern.

An advantage of the present fiberoptic wide-angle illuminating device, in addition to its space saving features, is its ease of assembly and alignment. A single lens is relatively easy to assemble and align. And yet with the miniaturized, single lens illuminating device of the present invention a wide angle of light can be projected.

Other features and advantages of the invention will become apparent from the following description, the accompanying drawings and the appended claims.

FIG. 1 is a plan view of a fiberoptic wide-angle illuminating device having a construction in accordance with the present invention;

FIG. 2 is a fragmentary side elevational, partly sectioned, view of the illuminating device taken along line 2--2 of FIG. 1, showing also a support housing of the device;

FIG. 3 is a fragmentary side elevational, partly in section showing various alternative features of the fiberoptic wide-angle illuminating device; and

FIG. 4 is a plan view of another embodiment of the fiberoptic wide-angle illuminating device of the present invention.

Referring to FIG. 1 of the drawings, there is illustrated a preferred embodiment of a fiberoptic wide-angle illuminating device, generally designated 10, having a construction in accordance with the present invention. While the illuminating device 10 of the present invention is generally applicable to a variety of lighting applications, it is particularly suited for use as a taillight, turn signal, fog or backup light for vehicular illumination purposes.

Referring to FIGS. 1 and 2, the fiberoptic spherical illuminating device 10 basically includes a fiberoptic cable 12 containing bundles of optical fibers 14 for conducting and emitting output light, a yoke 16 defining a single elongated aperture 18 in the configuration of a semi-circular arc aligned with output ends 14A of the optical fibers 14, and a single spherical optical lens 20 aligned with the single arcuate aperture 18. The arcuate aperture 18 receives and passes light emitted from the optical fibers 14 to the spherical lens 20. The spherical lens 20 receives the light and projects the light in a desired arcuate-shaped beam pattern "B". The arcuate-shaped aperture 18 provides wide-angle illumination. As shown in FIG. 1, the angle of arcuate-shaped aperture may be about 170.degree. and thus the spherical lens 20 will project the light in the arcuate beam pattern "B" of approximately 170.degree.. Actually, the angle of beam pattern "B" may be or may be caused to be greater than 170.degree. or even 180.degree.. A dispersion of light greater than 180.degree. is possible because yoke 16 may be made extremely thin, i.e. on the order of 0.04 inches thick. When using such a thin yoke, the beam splitting from one side of the yoke causes light to pass over and under the other side of the yoke. Some light will be blocked by the yoke, but because it is very thin, the overall beam pattern is maintained and, in that instance, it may be greater than 170.degree. or even 180.degree.. Of course, the extent of the beam pattern is also controlled by the shape and extent of housing 30 as will be explained in more detail below.

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 fiberoptic cable 12. Any suitable light source 24 can be utilized, such as the one described in my copending application Ser. No. 656,919 filed Feb. 19, 1991, which disclosure is incorporated herein by reference.

More particularly, yoke 16 has a generally Y-shaped configuration composed of a generally C-shaped head portion 26 and a linear neck portion 28 integrally attached to and extending from the bight of the C-shaped head portion 26. The neck portion 28 is axially aligned with the center "C" of the spherical lens 20 and a longitudinal axis "A" of the lens 20 extending through its center "C". The neck portion 28 receives and supports an end portion 12A of the fiberoptic cable 12. The C-shaped head portion 26 of the yoke 16 receives and supports the output ends 14A of the optical fibers 14 arranged in a splayed-out fashion in a row. Thus, as mentioned, optical fibers 14 are bundles of a large number of individual filaments on the order of 0.002 inches in diameter. Optical fibers 14 are spaced within a block 32 inside yoke 16 and at the output ends 14A are further splayed into a stack of 5-10 layers of filaments 0.02 to 0.04 inches thick. Such a splay will result in a fiberoptic ribbon the width of aperture 18. Block 32 may be an acrylic or epoxy material which will encapsulate optical fibers 14. A C-shaped opening the size of aperture 18 is cut and polished into block 32, exposing the output ends 14A of optical fibers 14. The output ends 14A are wetted with a wetting agent such as isopropyl alcohol and yoke 16 with aperture 18 formed therein is overlayed. The arcuate aperture 18 is defined on a concave side of the C-shaped head portion 26 of the yoke 16 and is aligned with and lies in the plane of the splayed optical fibers 14 for receiving and passing light emitted from the optical fibers.

The illuminating device 10 also includes a housing 30 and means for clamping the spherical lens 20 in the desired predetermined aligned relationship with the aperture 18 of the yoke 16. The neck portion 28 of the yoke 16 is mounted through a hole 42 in the rear side of the housing 30, whereas the spherical lens 20 protrudes through a large opening 34 in the front side of the housing 30. The size of opening 34, the location of the clamping means, the shape of housing 30, and the extent to which spherical lens 20 protrudes through opening 34, as well as the size of C-shaped head portion 26 of yoke 16, determine the angle of light emission from spherical lens 20, which may be adjusted by varying one or more of these parameters.

The clamping means includes a pair of threaded stems 36 mounted through opposite and axially aligned threaded holes 38 in the housing 30. The threaded stems 36 have concave-shaped inner ends 36A adapted to clamp against opposite top and bottom portions of the spherical lens 20 to retain the lens in alignment with the aperture 18. By turning threaded stems 36, the stems can be movably adjusted toward and away from the lens 20 for precisely locating it in aligned relationship with the aperture 18. Then, by using lock nuts 40, the threaded stems 36 can be locked at their adjusted portions.

As noted in FIGS. 1-2, aperture 18 is spaced a slight distance from spherical lens 20. Such a spacing is necessary to permit alignment of spherical lens 20 with aperture 18 using threaded stems 36. Alternatively, aperture 18 may be in direct contact with lens 20 and C-shaped head portion 26 of yoke 16 bonded in fixed relationship to lens 20. In that instance, adjustment may still be made possible by use of an enlarged hole 42 in housing 30 so that yoke 16 may move upon or down, back and forth with the movement of lens 20 as it is aligned.

Such an arrangement is shown in FIG. 3, which also shows other alternatives which may be used individually or in various combinations. Thus, in FIG. 3 there is shown a vertical cylindrical lens 20' which may be used in place of a spherical lens 20. The C-shaped head portions 26 of yoke 16 is bonded to vertical cylindrical lens 20'. Installation and alignment is accomplished by threading fiberoptic cable 12 having yoke 16 and vertical cylindrical lens 20' attached thereto into housing 30, through enlarged hole 42 and, then, using a single threaded stem 36 (which may be a set screw in this instance) to lock vertical cylindrical lens 20' in place. Hole 42 may thereafter by filled with a packing material (not shown) if desired.

In FIG. 4 yet another embodiment is shown having a yoke 16' of modified shape from that shown in FIG. 1. The housing would be adapted accordingly by relocating hole 42 within the housing to accommodate threading of fiberoptic cable 12 therethrough. As will be apparent, other modified shapes may be used for the yoke or housing.

Having thus described the fiberoptic spherical illuminating device of the present invention in detail and by reference to a preferred embodiment thereof, it will be apparent that modifications and variations are possible without departing from the scope of the invention defined in the appended claims.