HK1118889B - Led lighting system with helical fiber filament - Google Patents

Description

LED lighting system with helical fiber filament

Cross Reference to Related Applications

The present invention claims priority from US provisional patent application serial No.60/697,781, filed on 8.7.2005, the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present invention relates to a Light Emitting Diode (LED) lighting system with a helical fiber "filament".

Background

Lightweight, loss tolerant, high intensity LEDs have shown great promise for people who are interested in replacing traditional tungsten filament light sources. However, a problem with the use of such LEDs is that the available visible color spectrum is limited by the limited availability of LED colors. Thus, in commonly assigned US patent No.7,011,421 and in co-pending US patent application No.11/025,019, also incorporated herein by reference in its entirety, a lighting device using fluorescent and phosphorescent dyes is described, thereby allowing the emission of colored light that is not normally available using LEDs alone, without a significant increase in the cost and complexity of the lighting device. However, it is also desirable to be able to easily adjust the color of the light emitted by such LED/dye systems.

In addition, fluorescent dyes can migrate in areas of non-uniform illumination. The non-uniform illumination area can cause the dye exposed to the higher density to vibrate and become "hot", which in turn can cause the dye to migrate away from the higher density location. When the dye migrates, the resulting color emitted by the LED/dye system changes. It is therefore also desirable to reduce or eliminate dye migration in LED/dye systems.

Disclosure of Invention

The present invention meets these and other needs.

In general, the invention is a lighting system comprising a first helical light-transmitting fiber and an LED. The first helical light-transmitting fiber is doped with a first wavelength converting material and defines a helical axis. The LED has a light emitting portion for emitting light of a first color. The LED is axially aligned with the first helical fiber such that a portion of any light emitted by the LED passes through the open space between the turns of the first helical fiber and a portion of any light emitted by the LED will be received by the first helical fiber and converted to light of the second color.

According to an aspect of the present invention, the first helical fiber defines a cylindrical interior space and the LED is a side-emitting LED positioned with the light emitting portion inside the first helical fiber interior space. The system also has a cup-shaped light collecting and mixing member having a sidewall, a closed end, an open end, and an interior region. The light-collecting and mixing element is axially aligned within the first helical fiber such that the light-emitting portion of the LED and the first helical fiber are received with the interior region of the light-collecting and mixing element. The light collecting and mixing member collects and mixes the light of the first color and the light of the second color and guides the mixed light out of the open end. The system also includes means for adjusting the compression of the first helical fiber to adjust the amount of open space between the turns of the first helical fiber, thereby changing the percentages of the first color light and the second color light emitted by the illumination system.

More specifically, the means for regulating compression includes a first isolation member and a first plunger assembly. The separating member may be a light-transmitting tube. The plunger assembly may include a threaded shaft and a threaded shaft receiving nut. The LED may have a base portion connected to one end of the light-transmissive tube. The threaded nut may be connected to the other end of the light transmissive tube. The first helical fiber is located inside the light-transmitting tube. The threaded shaft is rotatably received in the threaded nut with one end of the threaded shaft adjacent to one end of the first helical fiber such that rotation of the threaded shaft adjusts the compression of the first helical fiber and the open space between the turns of the first helical fiber.

The illumination system may also have a light-transmissive member located around the exterior of the light-transmissive tube, or a light-reflective member located around a portion of the interior surface of the light-collecting and mixing member. The light-transmitting and light-reflecting parts both comprise a second wavelength converting material for converting a portion of the light emitted by the LED into a third color.

According to another aspect of the present invention, the lighting system further has a second helical fiber having a larger diameter than the first helical fiber and positioned about the first helical fiber in axial alignment with the first helical fiber. The second helical fiber is doped with a second wavelength converting material. The lighting system further may have means for adjusting the compression of the second helical fiber including a second light-transmissive tube and a tubular plunger slidably received within the second light-transmissive tube.

According to another aspect of the invention, the lighting system has a ring-shaped light-transmitting member having optical waveguide and light scattering properties, and a light-guiding housing for guiding light from the LED and the first helical fiber into the ring-shaped light-transmitting member. The light guide housing may have a disc-shaped top reflector member covering a top of the opening defined by the annular light-transmissive member. The top emitting member may also be flexible for adjusting the compression of the first helical fiber.

According to yet another aspect of the present invention, the illumination system may have a light-transmitting rod positioned such that at least a portion of the light-transmitting rod is inside the first helical fiber. The LED is a top-emitting LED and is positioned to emit light into the proximal end of the light-transmitting rod. A reflector cap is over the distal end of the light-transmissive rod. The light-transmitting rod may be bulb-shaped.

According to yet another aspect of the invention, the lighting system may have a light-transmissive tube positioned such that at least a portion of the light-transmissive tube is inside the first helical fiber. The reflector may be formed inside the light-transmitting tube to guide light out of the light-transmitting tube. The lighting system further may have a means, such as a solenoid, for adjusting the compression of the first helical fiber. Still further, the system may have a plurality of fibers doped with different wavelength converting materials and wound around the light-transmitting tube in parallel or in sections.

Another aspect of the invention utilizes an LED having a batwing radiation pattern and a fiber formed substantially in a dome shape and having an open top corresponding to a uniform central radiation area of the LED. A cap of suitable size is placed over the open top of the dome-shaped helical fiber.

In one embodiment, a light transmissive rod encases the first helical fiber. The light-transmitting rod and the first helical fiber are coaxially aligned, and a top-emitting LED is positioned to emit light into an end of the light-transmitting rod.

Drawings

FIG. 1 is a cut-away perspective view of a first exemplary embodiment of an LED lighting system having a helical fiber "filament" according to the present invention;

FIG. 2 is a side view of a first exemplary embodiment of an LED illumination system with a portion of the light collection and mixing component cut away;

FIG. 3 is a cut-away perspective view of a second exemplary embodiment of an LED lighting system according to the present invention;

FIG. 4 is a side view of a third exemplary embodiment of an LED lighting system according to the present invention, with a portion of the light collection and mixing component cut away;

FIG. 5 is a cut-away perspective view of a fourth exemplary embodiment of an LED lighting system according to the present invention;

FIG. 6 is a perspective view of a fifth exemplary embodiment of an LED lighting system according to the present invention;

FIGS. 7A and 7B are side views of the LED lighting system of FIG. 6;

FIG. 8 is a cross-sectional side view of a sixth exemplary embodiment of an LED lighting system according to the present invention;

FIG. 9 is a non-cross-sectional side view of the LED lighting system of FIG. 8;

fig. 10A and 10B are side views of a seventh exemplary embodiment of an LED lighting system according to the present invention;

11A and 11B are side views of an eighth exemplary embodiment of an LED lighting system according to the present invention;

fig. 12A and 12B are side views of a ninth exemplary embodiment of an LED lighting system according to the present invention;

fig. 13 is a side view of a tenth exemplary embodiment of an LED lighting system according to the present invention;

FIG. 14 is a graph of the radiation pattern produced by an exemplary LED;

fig. 15 is a side view of an eleventh exemplary embodiment of an LED lighting system according to the present invention;

FIG. 16 is a side view of a twelfth exemplary embodiment of an LED lighting system according to the present invention;

fig. 17 is a side view of a variation of the exemplary embodiment of the LED lighting system of fig. 16.

Detailed Description

The invention is an LED lighting system with a helical fiber "filament".

A. First exemplary embodiment: single helical fiber

As shown in fig. 1 and 2, a first exemplary embodiment 10 of an LED lighting system has a helical fiber 12, an LED14, a means 16 of adjusting the compression of the helical fiber 12, and a light collecting and mixing element 18.

The helical fiber 12 of the first exemplary embodiment is a light-transmitting fiber formed into a cylindrical coil, spiral, or helix. The helical fiber 12 is doped with a wavelength converting material, such as a fluorescent or phosphorescent dye or pigment. The helical axis of the helical fiber 12 defines a central axis 20 of the LED lighting system 10. The spiral fibers 12 may be made of a transparent or frosted light transmitting material, such as acrylic or the like.

The LED14 of the first exemplary embodiment is a side-emitting type LED. The LED14 is axially aligned with the helical axis of the helical fiber 12 and the central axis 20 of the LED lighting system. Also, the LED14 is positioned within the cylindrical interior space defined by the helical fiber 12. The LED14 has a light emitting portion 21 and a base portion 22. The LED base portion 22 provides mechanical and electrical connection for the LED 14. The components that operate the LEDs 14, including the wires for supplying power to the LEDs 14 and any necessary heat dissipation components for dissipating heat from the LEDs 14, are not shown, but are known to those skilled in the art.

The means 16 for adjusting the compression of the helical fiber 12 of the first exemplary embodiment includes an isolation member 24, a plunger assembly 26, and a base portion 22. The helical fiber 12 is positioned between the plunger assembly 26 and the LED base section 22, with the spacer member 24 separating the plunger assembly 26 from the LED base section 22. More specifically, the spacer member 24 of the first exemplary embodiment is a light-transmissive tube 28, and the plunger assembly 26 includes a threaded shaft 30 and a threaded shaft-receiving nut 32, with the base portion 22 being coupled to one end of the light-transmissive tube 28 such that the LED light-emitting portion 21 is located inside the light-transmissive tube 28. A threaded shaft receiving nut 32 is connected to the other end of the light-transmitting tube 28. The helical fiber 12 is located inside the light-transmitting tube 28 and around the LED light-emitting portion 21 and adjacent the LED base portion 22. The threaded shaft 30 is received in the threaded shaft receiving nut 32 such that one end of the threaded shaft 30 is adjacent the helical fiber 12. In addition, the means 16 for adjusting the compression of the helical fiber may also have a disk shaped member 34 positioned between the helical shaft 30 and the helical fiber 12.

It should be understood by those skilled in the art that other mechanical and electromechanical adjustment means, such as solenoids and the like, may be used to adjust the compression of the helical fibers of the exemplary embodiments described herein without departing from the spirit and scope of the present invention as described and claimed herein.

The light collecting and mixing element 18 is cup-shaped and positioned coaxially with the central axis 20 of the LED lighting system 10 and around the LED light emitting portion 21, the helical fiber 12 and a portion of the light transmissive tube 28. The light collecting and mixing element 18 has a closed end 36 and an open end 38. As shown in fig. 1 and 2, the threaded shaft-receiving nut 32 may be affixed to the outside of the closed end 36, and the closed end 36 may have an opening size that allows the threaded shaft 30 to protrude through the closed end 36 and into the interior of the light collecting and mixing component 18.

During operation, the LED light emitting portion 21 emits light of a first wavelength or color. A portion of the emitted light passes through the open space between the turns of the helical fiber 12 and a portion of the emitted light is received by the helical fiber 12 and converted to light of a second wavelength or color. The light collecting and mixing element 18 collects and mixes the light of the first color and the light of the second color and directs the mixed light out of the open end 38. Preferably, the LED14 emits light having a wavelength in the blue region of the color spectrum (relatively high energy and short wavelength), and the wavelength converting material in the helical fiber 12 converts a portion of the emitted light to a second color, such that the mixed light approximates the color and intensity of existing tungsten filament light sources.

Advantageously, the plunger assembly 26 may adjust the open space between the turns of the helical fiber 12 by compressing or decompressing the helical fiber 12, thereby changing the percentage of the first color light and the second color light present in the mixed light and the visual color of the mixed light. Rotation of the threaded shaft 30 about the threaded shaft receiving nut 32 will cause compression or decompression of the helical fiber 12. The disc shaped member 34 prevents the helical fiber 12 from being hit and twisted by the threaded shaft 30.

Also advantageously, the relatively small fiber cross-sectional area of the helical fiber 12 serves to reduce or eliminate any non-uniformity of the illumination area at any one point along the fiber, and thereby reduces or eliminates dye migration that occurs due to non-uniformity of the illumination area.

B. Second exemplary embodiment: the light-transmitting member is arranged around the light-transmitting tube

Fig. 3 shows a second exemplary embodiment 40, similar to the previously described system, but further having a small light-transmitting member 42, such as a translucent band, a second fiber, or a light-transmitting annular shaped member (as shown), doped with a different wavelength converting material, located around the exterior of the light-transmitting tube 28. In use, the light transmissive tube member 42 adds another degree of adjustment to the color of the mixed light directed out of the open end 38 of the light collecting and mixing member 18.

C. Third exemplary embodiment: the light reflecting member is around the inner surface of the light collecting and mixing member

Similarly, a third exemplary embodiment 50 is shown in fig. 4, similar to the system described in connection with fig. 1 and 2, but further having a light reflecting member 52, such as an annular reflective band, a paint coating, or the like, comprising a different wavelength converting material located around a portion of the interior surface of the light collecting and mixing element 18. In use, the light reflecting member 52 also adds another degree of adjustment to the color of the mixed light directed out of the open end 38 of the light collecting and mixing element 18.

D. Fourth exemplary embodiment: two filaments

Fig. 5 shows yet another exemplary embodiment 60 of an LED lighting system. As shown, similar to the systems described in connection with fig. 1 and 2, the exemplary LED lighting system has a first helical fiber 12, an LED14, a means 16 of adjusting the compression of the first helical fiber 12, and one end of a light helical fiber 62. The second helical fiber 62 is positioned between the first light-transmissive tube 28 and the second light-transmissive tube 74, around the LED light-emitting portion 21, and between the LED base portion 22 and the tubular plunger 76.

The light collecting and mixing element 18 is cup-shaped and houses at least the LED light emitting portion 21, the first helical fiber 12 and the second helical fiber 62 in its cup-shaped cavity. The light collecting and mixing element 18 is used to collect and mix light from the LED light emitting portion 21, the first helical fiber 12 and the second helical fiber 62. The light collecting and mixing element 18 has a closed end 36 and an open end 38. The closed end may be formed of a reflective plate 80 having a reflective inner surface. Closed end 36 may also have an opening size that allows second light-transmitting tube 74 to protrude through closed end 36 and into the interior of light-collecting mixing element 18 and serves to hold second light-transmitting tube 74 in a fixed position.

Preferably, the tubular plunger 76 also has a longitudinal slot 78 for allowing a support structure (not shown) to extend between the second light-transmitting tube 74 and the first light-transmitting tube 28 in order to hold the first light-transmitting tube 28 in a fixed position.

In use, the LED light emitting portion 21 emits light of a first wavelength or colour. A portion of the emitted light passes through the open space between the turns of the first helical fiber 12 and the second helical fiber 62. A portion of the emitted light is received by the first helical fiber 12 and converted to light of a second wavelength or color. A portion of the emitted light is received by the second helical fiber 62 and converted to light of a third wavelength or color. Additionally, a portion of the light at the second wavelength may also be received by the second helical fiber 62 and converted to light at a third wavelength. The light collecting and mixing element 18 collects and mixes the light of the first color, the light of the second color and the light of the third color and then directs the mixed light out of the open end 38 of the light collecting and mixing element 18.

Advantageously, the cylindrical plunger 72 and the tubular plunger 76 may allow for adjusting the open space between the turns of the first helical fiber 12 and the second helical fiber 62, respectively, by compressing or decompressing the first helical fiber 12 and the second helical fiber 62, thereby changing the percentages of the first color light, the second color light, and the third color light present in the mixed light and mixing the collecting and mixing element 18. However, the exemplary embodiment of fig. 5 also has a second helical fiber 62 and a means 66 for adjusting the compression of the second helical fiber 62.

The first helical fiber 12 and the second helical fiber 62 are both light-transmitting fibers formed into a cylindrical coil, spiral, or helix. However, the diameter of the second helical fiber 62 is larger than the diameter of the first helical fiber 12. The second helical fiber 62 is positioned about the first helical fiber and is coaxially aligned with the first helical fiber 12. The first helical fiber 12 is doped with a first wavelength converting material and the second helical fiber 62 is doped with a second wavelength converting material.

The LED14 is also a side-emission type LED having a light emitting portion 21 and a base portion 22. The LED14 is positioned such that its light emitting portion 21 is located within the cylindrical interior space defined by the first helical fiber 12. Since the second helical fiber 62 is positioned about the first helical fiber 12, the LED14 is also positioned within the cylindrical interior space defined by the second helical fiber 62. Also shown are wires 68 for supplying power to the LEDs 14 and a backing plate 70 that acts as a heat sink for dissipating heat from the LEDs 14.

The means 16 for adjusting the compression of the first helical fiber 12 includes the first light-transmitting tube 28 and the cylindrical plunger 72. The inner diameter of the first light-transmitting tube 28 is larger than the diameter of the first helical fiber 12 and the outer diameter of the first light-transmitting tube 28 is smaller than the diameter of the second helical fiber 62. The first light-transmitting tube 28 is positioned between the first helical fiber 12 and the second helical fiber 62. The diameter of the cylindrical plunger 72 is slightly smaller than the inner diameter of the first light-transmitting tube 28. A cylindrical plunger 72 is slidably received within the interior of the first light-transmitting tube 28, with one end of the cylindrical plunger 72 adjacent one end of the first helical fiber 12. The first helical fiber 12 is located inside the first light-transmitting tube 28, around the LED light-emitting portion 21, and between the LED base portion 22 and the cylindrical plunger 72.

The means 66 for adjusting the compression of the second helical fiber 62 includes a second light-transmitting tube 74 and a tubular plunger 76. The inner diameter of the second light-transmitting tube 74 is slightly larger than the diameter of the second helical fiber 62. A second light-transmitting tube 74 is positioned around the second helical fiber 62. The diameter of the tubular plunger 76 is substantially equal to the diameter of the second helical fiber 62. A tubular plunger 76 is slidably received between the second light-transmitting tube 74 and the first light-transmitting tube 28, and one end of the tubular plunger 76 is adjacent the visual color of the second combined light.

E. Fifth exemplary embodiment: lighting device for simulating quintuple tube or similar annular shape lighting

Fig. 6 is a perspective view of a fifth exemplary embodiment 90 of an LED lighting system with a helical fiber filament. The fifth exemplary embodiment 90 is a lighting device for simulating neon or similar lighting in a ring shape, such as described in co-pending and commonly assigned application Ser. No. 11//421,502, the entire disclosure of which is incorporated herein by reference.

The fifth exemplary embodiment 90 has a light-transmitting member 92 of an annular shape formed of a light-transmitting medium. The light-transmitting member 92 has a light-emitting surface 94. In use, the light-transmissive member 92 emits light having a substantially uniform intensity or brightness along the light-emitting surface 94, simulating neon or similar lighting in the shape of a toroid.

Fig. 7A is a side view of the fifth exemplary embodiment 90 of fig. 6. As shown, the exemplary embodiment 90 has an annular light-transmitting member 92, a helical fiber 12, an LED14, a means for adjusting the compression 16 of the helical fiber 12, and a light-guiding housing 96.

The light-transmitting member 92 is a "slotted" waveguide having optical waveguide and light scattering properties. As a result, the light-transmitting member 92 emits light along the light emitting surface 94 with uniformity and brightness that are characteristic of neon or similar lighting.

The LED 16 is positioned along the central axis of the annular light-transmitting member 92.

The helical fiber 12 is positioned coaxially with the light-transmissive member 92 and the LED 16.

The light guide housing 96 in the illustrated embodiment has a top reflective member 98 and a bottom reflective member 100 for directing light at the LED14 to the light transmissive member 92. The top reflective member 98 is disc-shaped and covers the top of the opening defined by the annular light-transmitting member 92. The bottom emission part 100 is annular and covers the bottom of the opening defined by the annular light-transmitting part 92. The LED14 is received in an opening defined by the annular bottom reflective member 100. Thus, the light guide housing 96 guides the light from the LED14 into the light-transmitting member 92 so that the light is emitted only through the light-transmitting member 92.

As shown in fig. 7B, the top reflective member 98 is flexible so that it also functions as the means 16 to adjust the compression of the helical fiber 12. By adjusting the compression of the helical fiber 12, the mixture of light from the LED14 and light from the helical fiber 12 reaching the light-transmitting member 92 is adjusted, changing the visual color of the light emitted by the light-transmitting member 92.

F. Sixth exemplary embodiment: light-transmitting rod

Fig. 8 shows a sixth exemplary embodiment 110 of an LED lighting system having a helical fiber 12, an LED14, a light-transmissive rod 112, a reflector 114, a substantially transparent outer jacket 116, and a reflective ring/LED holder/heat sink 118. The LEDs 14 are located in a reflective ring/LED holder/heat sink 118 to emit light into the proximal end of the rod 112. Preferably, the LED14 is a top emission type LED. The helical fiber 12 is positioned about the shaft 112, surrounding at least a portion of the shaft 112. The reflector 114 covers the distal end 122 of the rod 112 (opposite the LED 14). A substantially transparent sheath 116 encases the rod 112 and the helical fiber 12.

Fig. 9 shows a sixth exemplary embodiment 110 of an assembled LED lighting system. In addition, the light source includes potting compound (not shown) between the LED14 and the light transmissive rod 112. Furthermore, the LED lighting system includes conductive grease (not shown) between the LEDs 14 and the reflective ring/LED holder/heat sink 118. Further, the proximal end 20 of the shaft 112 may be smooth or rough (lambertian) or curved. The sleeve 116 holds an index matching fluid (not shown) for optically coupling the rod 112 to the helical fiber 12. Alternatively, if the rod 112 is made of a scattering material, such as DR acrylic, then the sheath 116 and index matching fluid used to connect the rod 112 to the helical fiber 12 are not required.

In use, light is generally conducted along the axis of the rod 112, and the rod 112 acts as a waveguide. The index matching fluid disrupts the interface between the helical fiber 12 and the rod 112 and causes the helical fiber 12 to receive a portion of the light emitted by the rod 112. The wavelength converting material of the helical fiber 12 causes the light passing through the helical fiber 12 to have a color different from the color of the LED 14. The reflector 114 also directs light into the helical fiber 12. In addition, another reflector or mirror (not shown) may be located at the proximal end 120 of the shaft 112 to direct light into the helical fiber 12. Thus, the helical fiber 12 acts as a "filament".

The color (or hue) of the emitted light can be controlled according to the following six variables: (a) the wavelength or color of light emitted by the LED 14; (b) the winding density of the helical fiber 12; (c) the cross-sectional shape of the helical fiber 12; (d) the thickness of the helical fiber 12; (e) the color and density of the dye in the helical fiber 12; and (f) the color and density of any dye in the rod 112 and sleeve 116. The winding density of the helical fiber 12 can be easily varied, although a number of variables must be established in advance.

G. Seventh exemplary embodiment: light-transmitting tube with solenoid actuator

In a seventh exemplary embodiment 130 as shown in fig. 10A and 10B, the helical fiber 12 is compressed using a solenoid 132. The seventh exemplary embodiment 130 has a light-transmissive tube 131, the tube 131 having a reflector 134 formed in the middle to direct light out to the side of the rod 112. It should be noted that compression means other than the solenoid 132 may be used. In addition, other reflector arrangements may be used without departing from the teachings of the present invention. For example, the formed reflector 134 may be moved along the length of the rod 112 to achieve a desired effect.

By varying the winding density of the helical fiber 12 in this manner, the color (or hue) of the emitted light can be varied as desired. Notably, the amount of unaltered light allowed to escape is greater in fig. 10A than in fig. 10B. In fig. 10B, the hue is shifted away from the unchanged color of the light emitted from the LED14 and towards the hue of the light emitted by the wavelength converting material of the helical fiber 12.

If a phosphorescent dye is used, the helical fiber 12 will continue to emit light even after the LED14 is turned off. Such "afterglow" will be projected if the LED light source is placed at the focus of the reflector or collector system.

Other benefits may be obtained by adding a dye to tube 131.

H. Eighth exemplary embodiment: light-transmitting tube with multiple parallel wound helical fibers

Fig. 11A and 11B show an eighth exemplary embodiment having a plurality of helical fibers 12, 62, 142, each doped with a different wavelength converting material. The plurality of helical fibers 12, 62, 142 are wound in parallel.

I. Ninth exemplary embodiment: light-transmitting tube with multiple helical fibers wound in sections

Fig. 12A and 12B illustrate an eighth exemplary embodiment having a plurality of helical fibers 12, 62, 142, each doped with a different wavelength converting material. The plurality of helical fibers 12, 62, 142 are wound in sections.

J. Tenth exemplary embodiment: bulb-shaped rod

Fig. 13 shows a tenth exemplary embodiment 160 of an LED lighting system. The tenth embodiment 160 has a bulb-shaped stem 162, wherein the bulb-shaped stem 162 has a proximal end 164 and a distal end 166, and a reflector 168 located on the distal end 166. An LED (not shown) may be positioned to emit light into the proximal end 164 of the bulb-shaped rod 162. In one variation, the bulb 36 is doped with a dye. The helical fiber 12 is positioned around the bulb-shaped rod 162. The helical fiber 12 is doped with a wavelength converting material.

K. Eleventh exemplary embodiment: dome shaped helical shaped fiber

Selecting a geometry and material that is resistant to dye migration will provide an LED lighting system with reduced or eliminated dye migration. One aspect of the geometry that is resistant to dye migration is the selection of LEDs that have a substantially uniform portion across their radiation intensity pattern. For example, fig. 14 shows a radiation pattern 170, referred to as a batwing-shaped pattern, produced by LED model/component No. lxhl-MB1C, commercially available from u.s.llc Lumileds Lighting. As shown, the radiation pattern 170 is fairly uniform in a central region from about-20 to +20 degrees. However, a radiation intensity gradient capable of causing dye migration exists outside the central region.

Fig. 15 shows an eleventh exemplary embodiment of an LED lighting system having an LED14, a dome-shaped helical fiber 182, and an end cap 184. More specifically, in this embodiment, an LED14, such as the Lumiled LED described above, is selected that has a substantially uniform radiation intensity pattern in a central region that extends about 20 degrees around the radiation axis of the LED 14. The end cap 184 is spaced from the LED14 and positioned such that its edge intersects the uniform radiation intensity pattern of the LED14, corresponding to the flattened area shown in the batwing distribution. The end cap 184 may be a transparent or translucent material doped with a dye. Because the radiation intensity pattern is substantially uniform across the end cap 184, migration of any dye is minimized. The end cap 184 may also be a reflective material. The dome-shaped helical fiber 182 is centered on the radiation axis of the LED14 between the LED14 and the end cap 184. The diameter of the fiber is selected such that the relative intensity at any point in the helical fiber 182 varies by less than 10%.

K. Twelfth exemplary embodiment: helical fiber wrapped in light-transmitting rod

Fig. 16 and 17 show a twelfth exemplary embodiment of the invention having an LED14, a helical fiber 12, and a light-transmissive rod 112. The helical fiber 12 is encased in a light transmissive rod 112. The light emitted by the LED14 is confined by the light-transmitting rod 112 and is symmetrically distributed perpendicular to the axis. Light-transmitting rod 112 may be transparent or scattering. Referring to fig. 17, the distal end of the light-transmitting rod is coated with paint or bandaged to reflect light.

Other embodiments will be apparent to those skilled in the art without departing from the teachings of the invention or the scope of the following claims. This detailed description, and particularly the specific details of the exemplary embodiments described herein, are given primarily for clearness of understanding, so no unnecessary limitations are to be understood therefrom, for modifications will become obvious to those skilled in the art upon reading this disclosure and may be made without departing from the spirit or scope of the invention as claimed.

Claims (28)

1. An illumination system, comprising:

a first helical light-transmitting fiber formed in a helical shape, the first helical light-transmitting fiber doped with a first wavelength converting material, the first helical light-transmitting fiber defining a helical axis; and

an LED having a light emitting portion for emitting light of a first color, the LED being axially aligned with the first helical light-transmitting fiber such that a portion of any light emitted by the LED passes through open spaces between turns of the first helical light-transmitting fiber and a portion of any light emitted by the LED will be received by the first helical light-transmitting fiber and converted to light of a second color.

2. The lighting system of claim 1, wherein the first helical light-transmitting fiber further defines a cylindrical interior space, wherein the LED is a side-emitting LED having a light-emitting portion, and wherein the LED light-emitting portion is located in the cylindrical interior space of the first helical light-transmitting fiber.

3. The lighting system of claim 2, further having a cup-shaped light collecting and mixing element having a side wall, a closed end, an open end and an interior region and being axially aligned with said first helical light transmitting fiber such that said LED light emitting portion and said first helical light transmitting fiber are received within the interior region of said light collecting and mixing element, whereby said light collecting and mixing element collects and mixes light of a first color and light of a second color and directs the mixed light out of said open end.

4. The lighting system of claim 3, further comprising means for adjusting the compression of said first helical light-transmitting fiber to adjust the amount of open space between said turns of said first helical light-transmitting fiber, thereby changing the percentage of light of said first color and light of said second color emitted by said lighting system.

5. The lighting system of claim 4, wherein said side-emitting LED further has a base portion for providing mechanical and electrical connection of said side-emitting LED, and wherein said means for adjusting said compression of said first helical light-transmitting fiber comprises a first spacer component and a first plunger assembly, said first spacer component separating said first plunger assembly from said LED base portion, said first helical light-transmitting fiber being positioned between said first plunger assembly and said LED base portion.

6. The lighting system of claim 5, wherein said isolation member is a light-transmissive tube, and wherein said plunger assembly includes a threaded shaft and a threaded shaft-receiving nut, said LED base portion being connected at one end of said light-transmissive tube, said threaded shaft-receiving nut being connected at the other end of said light-transmissive tube, said first helical light-transmissive fiber being located inside said light-transmissive tube, said threaded shaft being rotatably received in said threaded shaft-receiving nut, one end of said shaft being adjacent to one end of said first helical light-transmissive fiber, such that rotation of said threaded shaft will adjust said compression of said first helical light-transmissive fiber and said open space between said turns of said first helical light-transmissive fiber.

7. The lighting system of claim 6, further having a light-transmissive member located around the exterior of the light-transmissive tube, the light-transmissive member doped with a second wavelength converting material.

8. The illumination system of claim 6, further having a light reflecting component positioned around a portion of the interior surface of the light collecting and mixing component, the light reflecting component comprising a second wavelength converting material.

9. The lighting system of claim 1, further having a second helical light-transmitting fiber of larger diameter than the first helical light-transmitting fiber, the second helical light-transmitting fiber being located around and axially aligned with the first helical light-transmitting fiber, the second helical light-transmitting fiber being doped with a second wavelength-converting material, such that a portion of any light emitted by the LED will pass through open spaces between turns of the second helical light-transmitting fiber, and a portion of any light emitted by the side-emitting LED will be received by the second helical light-transmitting fiber and converted to light of a third color.

10. The lighting system of claim 9, wherein the first helical light-transmitting fiber further defines a cylindrical interior space, wherein the LED is a side-emitting LED having a light-emitting portion, and wherein the LED light-emitting portion is located in the cylindrical interior space of the first helical light-transmitting fiber.

11. The lighting system of claim 10, further having a cup-shaped light collecting and mixing element having a side wall, a closed end, an open end and an interior region and being axially aligned with said first helical light transmitting fiber such that said LED light emitting portion, said first helical light transmitting fiber and said second helical light transmitting fiber are received in the interior region of said light collecting and mixing element, whereby said light collecting and mixing element collects and mixes light of a first color, light of a second color and light of a third color and directs the mixed light out of said open end.

12. The lighting system of claim 11, further comprising means for adjusting the compression of said first helical light-transmitting fiber, and means for adjusting the compression of said second helical light-transmitting fiber for adjusting the amount of open space between turns of said first helical light-transmitting fiber and the amount of open space between turns of said second helical light-transmitting fiber, thereby changing the percentages of said first color light, said second color light, and said third color light emitted by said system.

13. The lighting system as set forth in claim 12,

wherein the side-view LED further has a base portion for providing mechanical and electrical connection of the side-view LED,

wherein said means for adjusting the compression of said first helical light-transmitting fiber comprises a first light-transmitting tube and a cylindrical plunger slidingly received in said first light-transmitting tube, said first light-transmitting tube being located between said first helical light-transmitting fiber and said second helical light-transmitting fiber, said first helical light-transmitting fiber being located between said LED base portion and said cylindrical plunger, and

wherein said means for adjusting the compression of said second helical light-transmitting fiber comprises a second light-transmitting tube and a tubular plunger slidably received in said second light-transmitting tube, said second light-transmitting tube being positioned around said second helical light-transmitting fiber, said second helical light-transmitting fiber being positioned between said LED base portion and said tubular plunger.

14. The lighting system of claim 13, wherein the tubular plunger has a longitudinal slit for allowing a support structure to extend between the second light-transmissive tube and the first light-transmissive tube so as to hold the first light-transmissive tube in a fixed position.

15. The lighting system of claim 1, further having:

an annular light-transmitting member having optical waveguide and light scattering properties and positioned coaxially with the first helical light-transmitting fiber; and

a light-conducting housing for conducting light from said LED and said first helical light-transmitting fiber into said light-transmitting member such that said annular light-transmitting member will emit light having a substantially uniform intensity or brightness for simulating annular-shaped neon lighting.

16. The lighting system of claim 15, wherein the light guide housing has:

a disc-shaped top reflective member covering a top of an opening defined by the annular light transmissive member; and

an annular bottom reflective member covering a bottom of the opening defined by the annular light transmissive member, the LED being received in the opening defined by the annular bottom reflective member.

17. The lighting system of claim 16, wherein said top reflective member is flexible for adjusting compression of said first helical light-transmitting fiber.

18. The lighting system of claim 1, further comprising:

a light-transmitting rod positioned such that at least a portion of the light-transmitting rod is inside the first helical light-transmitting fiber, the light-transmitting rod having a proximal end and a distal end; and

a reflector covering said distal end of said light-transmitting rod;

wherein the LED is a top-emitting LED positioned to emit light into the proximal end of the light-transmitting rod.

19. The lighting system of claim 18, wherein said light-transmitting rod is made of a light-scattering material for optically coupling said first helical light-transmitting fiber to said light-transmitting rod.

20. The lighting system of claim 18, further having:

a substantially transparent outer cover encasing said light-transmitting rod and said first helical light-transmitting fiber; and

an index matching fluid filling a void between the housing and the light-transmitting rod for optically coupling the first helical light-transmitting fiber to the light-transmitting rod.

21. The lighting system of claim 18, wherein the light-transmitting rod is bulb-shaped.

22. The lighting system of claim 1, further comprising:

a light-transmissive tube positioned such that at least a portion of the light-transmissive tube is inside the first helical light-transmissive fiber;

a reflector formed inside the tube to direct light out of the sides of the tube; and

means for adjusting the compression of said first helical light-transmitting fiber for adjusting the amount of open space between turns of said first helical light-transmitting fiber, thereby changing the percentage of light of said first color and light of said second color emitted by said illumination system.

23. The lighting system of claim 22, wherein said means to adjust said compression of said first helical light-transmitting fiber is a solenoid.

24. The lighting system of claim 22, further comprising a second helical light-transmitting fiber doped with a second wavelength converting material and a third helical light-transmitting fiber doped with a third wavelength converting material, said first, second and third helical light-transmitting fibers being wound in parallel around said light-transmitting tube.

25. The lighting system of claim 22, further comprising a second helical light-transmitting fiber doped with a second wavelength converting material and a third helical light-transmitting fiber doped with a third wavelength converting material, said first, second and third helical light-transmitting fibers being wound around said light-transmitting tube in separate portions.

26. The lighting system of claim 1, wherein said LED has a batwing radiation pattern with a uniform central area around a radiation axis of said LED, wherein said first helical light-transmitting fiber is formed in the shape of a substantially dome-shaped helix, having an open top corresponding to said LED radiation pattern uniform central area, and further having an end cap dimensioned such that its circular edge corresponds to said first helical light-transmitting fiber open top and is positioned such that said edge intersects said batwing radiation pattern of said LED, the diameter of said first helical light-transmitting fiber being selected such that the variation in relative intensity at any point in said first helical light-transmitting fiber is less than 10%.

27. The lighting system of claim 1, further having a light-transmitting rod encasing said first helical light-transmitting fiber, said light-transmitting rod and said first helical light-transmitting fiber being coaxially aligned, said light-transmitting rod having a proximal end, wherein said LED is a top-emitting LED positioned to emit light into said proximal end of said light-transmitting rod.

28. The lighting system of claim 27, wherein said light-transmitting rod further has a distal end having a light-reflecting coating for reflecting light back into said light-transmitting rod.