EP1073922A1 - Compact optical system with turn and color mixing - Google Patents
Compact optical system with turn and color mixingInfo
- Publication number
- EP1073922A1 EP1073922A1 EP99973719A EP99973719A EP1073922A1 EP 1073922 A1 EP1073922 A1 EP 1073922A1 EP 99973719 A EP99973719 A EP 99973719A EP 99973719 A EP99973719 A EP 99973719A EP 1073922 A1 EP1073922 A1 EP 1073922A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- light
- optical assembly
- cross
- bend region
- fiber
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0005—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/0001—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems
- G02B6/0005—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings specially adapted for lighting devices or systems the light guides being of the fibre type
- G02B6/0006—Coupling light into the fibre
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/262—Optical details of coupling light into, or out of, or between fibre ends, e.g. special fibre end shapes or associated optical elements
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/26—Optical coupling means
- G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
- G02B6/2804—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers
- G02B6/2808—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals forming multipart couplers without wavelength selective elements, e.g. "T" couplers, star couplers using a mixing element which evenly distributes an input signal over a number of outputs
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4201—Packages, e.g. shape, construction, internal or external details
- G02B6/4204—Packages, e.g. shape, construction, internal or external details the coupling comprising intermediate optical elements, e.g. lenses, holograms
- G02B6/4206—Optical features
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4296—Coupling light guides with opto-electronic elements coupling with sources of high radiant energy, e.g. high power lasers, high temperature light sources
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/14—Mode converters
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/42—Coupling light guides with opto-electronic elements
- G02B6/4298—Coupling light guides with opto-electronic elements coupling with non-coherent light sources and/or radiation detectors, e.g. lamps, incandescent bulbs, scintillation chambers
Definitions
- This application is directed to optically coupling a high brightness light source to a remote end use via a light conductor and, more particularly, to an optical system that provides improved light mixing and more uniform light intensity and color.
- the invention is particularly applicable to optical systems of the type as shown and described in U.S. Patent No. 5,341,445 - Davenport, et al.; 5,469,337 - Cassarly, et al.; and 5,691,696 - Mazies, et al.
- the details of the '445; '337; and '696 patents are incorporated herein by reference.
- these patents disclose a high brightness light source, for example one measuring in excess of 50,000 lumens per square centimeter, associated with a reflector arrangement that inputs light to one or more optical light conductors, pipes or fibers.
- Selected applications of these types of systems require a light fiber to undergo a tight bend, for example, when turning a corner.
- a commercial embodiment exhibiting this requirement is an automotive lighting system where the light source is located in a central location such as under the engine hood. The headlights are located on either side of the engine compartment and directed forwardly of the vehicle, thus, necessitating that the light fibers undergo a bend or turn to direct the light in a forward direction.
- This bend of the light fibers can approach 105 degrees in a small area, for example, a two-by-two inch box which adversely affects optical transmission.
- a tight bend would adversely impact on light output from the headlamp system.
- Intensity or angular distribution and illuminance or spatial distribution are both impacted.
- the turn must be accomplished with no significant loss and no significant increase in the angular distribution.
- a Teflon clad light fiber of a diameter of 0.5 inches is difficult to bend through a small radius in a headlamp assembly.
- the cladding surrounding the core material starts to kink at a bend radius of approximately four inches.
- brightness significantly decreases at a bend radius of about seven inches.
- the light has a red perimeter with a white interior portion as described in the '445 patent.
- One proposed solution to the color separation as disclosed in the '445 patent is to use a square coupler.
- the square coupler provides for mixing of the intensity and color of the light as it travels through the square coupler.
- the polygonal-shaped square coupler provides an increased number of internal reflections per unit length thereby achieving a more uniform distribution of the light intensity and improved color mixing over that achieved with a standard, cylindrical tubular coupling member.
- Color separation is also a problem when two independent light sources are used.
- two independent sources there are presently no solutions that provide high performance, i.e., long life, minimal complexity, maximum beam lumens, and minimal color separation.
- the present invention contemplates a new and improved optical assembly that propagates light from a light source to an associated end use through a tight bend region, providing an assembly that is simple, economical, and effectively implemented.
- a light fiber having a first cross-section defined in a bend region.
- a first non-imaging optical component transmits light from the source to a first or input end of the bend region thereby increasing the angular distribution of light through the light fiber.
- a second non-imaging optical component is disposed to receive light from a second or output end of the bend region and decrease the angular distribution of light.
- a first conductor transmits light to the output of the first non-imaging optical component and has an input cross-sectional dimension in the plane of the bend greater than that of the light fiber.
- a second conductor receives light from the output of the second non-imaging component.
- the second conductor has an input cross-sectional dimension in the plane of the bend greater than the light fiber.
- the non-imaging optical components are tapered light conductors having a first cross-sectional area at one end adjacent the light pipe that tapers to a larger, second cross-sectional area at another end.
- the non-imaging optical components have a cross-sectional configuration selected from a group of polygonal shapes.
- a principal advantage of the invention is the ability to bend the light fiber through a tight turn or twist without severely impacting dimensional constraints or optical performance.
- Another advantage of the invention resides in improved brightness at the output end of the bend region.
- Yet another advantage of the invention is improved color mixing without brightness reduction.
- Figure 1 which is a schematic representation of an automotive vehicle with a central lighting system
- Figure 2 illustrates a simple bend region of an unclad fiber of radius r shown bent at a radius R of approximately 90 degrees;
- Figure 3 illustrates a preferred optical assembly designed as a replacement for the bent light fiber of Figure 2;
- Figure 4 illustrates another preferred optical assembly for efficiently propagating light through a bend region with angle-to-area tapers at opposite ends of the bend region;
- Figures 5A and 5B are schematic representations of compact optical systems illustrating different output optical elements
- Figures 6A, 6B, and 6C illustrate side, end and bottom views, respectively, of a preferred polygonal cross-sectional shape of a non-imaging optical component; and Figures 7A, 7B, and 7C illustrate side, end, and bottom views, respectively, of an alternative configuration of a non-imaging optical component.
- Figure 1 is a schematic representation under the hood of an automotive vehicle 20.
- the light source is a high brightness light source such as an instant start metal halide lamp or comparable HID source.
- First and second light pipes or fibers 32a, 32b are optically coupled to the light source 30 to receive light at an input end 34a, 34b and propagate the light to a second or output end 36a, 36b.
- like elements will be referred to with the a and b suffixes and description of one is applicable to the other unless specifically noted otherwise
- a and b suffixes and description of one is applicable to the other unless specifically noted otherwise.
- the end use of the light is disposed at a remote location from the central light source and, because of the use of light fibers, multiple end uses located at spaced positions from one another can all be connected to a single light source.
- the end use is a headlamp 40 illustrated as discrete low beam and high beam fixtures.
- the light fiber 32a, 32b propagates the light from the source 30 to the headlamps where light emanating from the fiber is now the source for the headlamp.
- This type of assembly provides a much smaller cone angle for the light and allows additional optical components to be attached directly to the fiber. This assembly also eliminates problems associated with standard headlamps which require special considerations, due to thermal issues associated with the high temperature light source.
- light which radiates from the fiber end 36a, 36b is usually collimated and beam forming optics (not shown) are added to provide a desired output pattern.
- beam forming optics Just as with standard headlamps, various combinations of reflective and refractive optics can be used.
- tight bend region 50 is disposed adjacent the outlet ends 36b of the fibers just prior to connection with the headlamp.
- this particular embodiment includes a tight bend region that extends through a constant radius R in a single plane, the principles of the present invention need not be so limited.
- the light fiber will be described as having a circular cross-section (referenced by radius r) although the invention applies to fibers of various cross-sectional configuration such as rectangular, oval, or other cross-sections.
- a bent region of the fiber can impact the light distribution from the end of the fiber.
- the light distribution is often described by parameters such as (i) intensity or angular distribution, (ii) illuminance or spatial distribution, and (iii) total flux out of the fiber.
- a fiber might encounter a 105 degree turn in a dimensional region defined as a 2" x 2" box and the turn must be accomplished with no significant loss and no significant increase in the angular distribution of the light.
- a twelve millimeter diameter light fiber having a Teflon cladding surrounding the core material starts to kink at a bend radius of approximately four inches. The brightness decreases at a bend radius of approximately seven inches.
- Figure 2 is an enlarged detail of the bend region of the light fiber 32.
- the light fiber is shown as having a radius r and the degree of bend through the region 50 is represented by radius R defined about axis 52.
- the illustrated light fiber is merely representative of a variety of configurations that the fiber can adopt and that are improved by applying the teachings of the subject invention.
- Figure 3 shows a compact optical assembly that can be inserted into the assembly as a unit.
- a box is defined by a length and width of X x X.
- bending the fiber results in a loss of brightness where the ratio of the fiber radius r to the bend radius R is small.
- the radius of the fiber is relatively large, there is a greater change in the brightness as light propagates through the bend region.
- a smaller diameter or smaller radius fiber is used.
- a first non-imaging optical component 60 At the input end of the bend region is provided a first non-imaging optical component 60.
- the first non-imaging optical component is an angle-to-area taper.
- a second non-imaging optical component 62 is provided at the output end of the bend region.
- the preferred embodiment of Figure 3 is an angle-to-area taper section.
- the first tapered component increases the angles as the light propagates from a large diameter end 60a to the small diameter end 60b where the light enters the bent fiber 64 through region 50.
- the second tapered component subsequently reduces the light angles as the light is transferred from an input end 62a having a small diameter to the large diameter second end 62b.
- the higher angles introduced by converting to a smaller diameter fiber 64 in the bend region are less influenced by small changes in the angular distribution. For example, six degrees added to a twenty-six degree angle is much more significant than six degrees added to a forty-two degree angle. Moreover, the higher angles are not changed as much as the lower angles. Thus in the arrangement of Figure 3, the ratio of the fiber diameter to the bend radius ratio is greater than that in Figure 2 thereby resulting in a smaller change in brightness through the bend region.
- the second non-imaging optical component transforms the angular distribution to the spread desired for the end use or continued propagation downstream of the bend region without.
- first nonimaging component and second nonimaging component are all extruded components that are subsequently joined together.
- a boot or dust cover 66 may enclose the optical assembly if desired.
- Figure 4 illustrates an embodiment where the dimensional constraints of the lighting system are not as critical. Accordingly, extended inlead and outlead areas are permitted so that the angle-to-area converter need not be confined to a compact package like in Figure 3. That is, the same small radius fiber 64 is used but its bend radius R is larger than that in Figure 3. The angle to area tapers then extend from the opposite ends of the bend region fiber 64.
- color separation can occur in systems using independent light sources.
- high intensity discharge sources provide a red perimeter and a white interior.
- light from different types of light sources has distinctive colors.
- Figures 5A and 5B demonstrate that the optical assembly is not limited to the automotive vehicle environment.
- a light source 70 is vertically mounted with an associated reflector 72 in this arrangement.
- a significant amount of color separation may occur at the input end of the first non- imaging optical component 74.
- a different angle-to-area converter is used, specifically a compound parabolic collector or CPC which is extremely compact and collects the light and converts it to different angles in a manner well known in the art.
- the small diameter of the bent light fiber 76 preserves brightness and results in color mixing as described above.
- the light then proceeds through the second non-imaging optical component 78 — here, again, a CPC.
- the light exits the second CPC and is directed through a lens 80 ( Figure 5A) or a reflective lens 82 ( Figure 5B) .
- Figures 6A - 6C and 7A - 7C likewise illustrate that still other configurations of the non-imaging optical component may be used.
- the non-imaging optical components may be hollow or solid.
- the embodiments of Figures 6A - 6C and Figures 7A - 7C disclose polygonal perimeters 90a-d, 92a-d, respectively, that provide an effective angle-to-area conversion of the light.
- the invention has been described with reference to the preferred embodiments. Obviously, modifications and alterations will occur to others upon a reading and understanding of this specification. It is intended to include all such modifications and alterations insofar as they come within the scope of the appended claims of the equivalents thereof.
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Optics & Photonics (AREA)
- Light Guides In General And Applications Therefor (AREA)
Abstract
Description
Claims
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/US1999/004023 WO2000050940A1 (en) | 1999-02-24 | 1999-02-24 | Compact optical system with turn and color mixing |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1073922A1 true EP1073922A1 (en) | 2001-02-07 |
EP1073922A4 EP1073922A4 (en) | 2001-05-16 |
Family
ID=22272243
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99973719A Withdrawn EP1073922A4 (en) | 1999-02-24 | 1999-02-24 | Compact optical system with turn and color mixing |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP1073922A4 (en) |
JP (1) | JP2002538488A (en) |
WO (1) | WO2000050940A1 (en) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
FI125512B (en) * | 2012-12-11 | 2015-11-13 | Rofin Sinar Laser Gmbh | Fiber optic shape mixer and method for making it |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5479545A (en) * | 1992-03-27 | 1995-12-26 | General Electric Company | Reverse flared optical coupling member for use with a high brightness light source |
JP3493696B2 (en) * | 1993-10-20 | 2004-02-03 | 株式会社デンソー | Lighting equipment |
JPH07326204A (en) * | 1994-05-31 | 1995-12-12 | Nippondenso Co Ltd | Vehicle lighting fixture |
-
1999
- 1999-02-24 EP EP99973719A patent/EP1073922A4/en not_active Withdrawn
- 1999-02-24 JP JP2000601479A patent/JP2002538488A/en not_active Withdrawn
- 1999-02-24 WO PCT/US1999/004023 patent/WO2000050940A1/en not_active Application Discontinuation
Non-Patent Citations (2)
Title |
---|
No further relevant documents disclosed * |
See also references of WO0050940A1 * |
Also Published As
Publication number | Publication date |
---|---|
JP2002538488A (en) | 2002-11-12 |
EP1073922A4 (en) | 2001-05-16 |
WO2000050940A1 (en) | 2000-08-31 |
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Legal Events
Date | Code | Title | Description |
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PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
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AK | Designated contracting states |
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A4 | Supplementary search report drawn up and despatched |
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AK | Designated contracting states |
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RIC1 | Information provided on ipc code assigned before grant |
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RIN1 | Information on inventor provided before grant (corrected) |
Inventor name: NAGLE, RICHARD, CHARLES Inventor name: DAVENPORT, JOHN, MARTIN Inventor name: HANSLER, RICHARD, LOWELL Inventor name: CASSARLY, WILLIAM, JAMES |
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STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
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18D | Application deemed to be withdrawn |
Effective date: 20050830 |