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
  • G02B6/0006—Coupling light into the fibre
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
  • G02B17/02—Catoptric systems, e.g. image erecting and reversing system
  • G02B17/06—Catoptric systems, e.g. image erecting and reversing system using mirrors only, i.e. having only one curved mirror
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B17/00—Systems with reflecting surfaces, with or without refracting elements
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
  • G02B19/0019—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors)
  • G02B19/0023—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed having reflective surfaces only (e.g. louvre systems, systems with multiple planar reflectors) at least one surface having optical power
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0004—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed
  • G02B19/0028—Condensers, e.g. light collectors or similar non-imaging optics characterised by the optical means employed refractive and reflective surfaces, e.g. non-imaging catadioptric systems
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B19/00—Condensers, e.g. light collectors or similar non-imaging optics
  • G02B19/0033—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use
  • G02B19/0047—Condensers, e.g. light collectors or similar non-imaging optics characterised by the use for use with a light source
• • 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
  • G02B6/4298—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

• the invention relates to systems for collecting and condensing electromagnetic radiation, such as light, and, in particular, to a system employing a pair of opposed concave reflector surfaces for collecting radiation emitted from a radiation source and focusing the collected radiated onto a target.
• the objective for systems that collect, condense, and couple light into a standard waveguide, such as a single fiber, a fiber bundle, or a homogenizer, is to maximize the brightness of the light at the target (i.e., the input end of the waveguide).
• a standard waveguide such as a single fiber, a fiber bundle, or a homogenizer.
• Prior art systems using on-axis reflectors and employing spherical, ellipsoidal, and parabolic reflectors have the advantage of being circularly symmetric.
• reflectors intrinsically degrade the brightness of the light source due to the variation of the magnification of light emitted from the source at different angles and impinging on different portions of the reflective surface.
• Off-axis systems which are not circularly symmetric, overcome the variations of magnification to a large extent and also employ spherical, ellipsoidal, and parabolic reflectors.
• the invention includes a device for collecting radiation emitted from a source of electromagnetic radiation and condensing the collected radiation into a target.
• the device comprises a collecting reflector having a concave reflective surface and an opening formed therethrough and a focusing reflector having a concave reflective surface and an opening formed therethrough.
• the collecting and focusing reflectors are positioned and oriented with their respective concave reflective surfaces in opposed, facing relation.
• the focusing reflector is positioned with respect to the collecting reflector so that a source of electromagnetic radiation positioned near the opening formed in the focusing reflector will reflect at least a portion of its electromagnetic radiation through the opening toward the concave reflective surface of the collecting reflector.
• the collecting reflector is positioned with respect to the focusing reflector so that electromagnetic radiation reflected by the concave reflective surface of the focusing reflector is transmitted through the opening formed through the collecting reflector toward a target positioned near the opening formed in the collecting reflector.
• the collecting reflector reflects at least a portion of the electromagnetic radiation incident thereon toward the concave reflective surface of the focusing reflector, and the focusing reflector reflects at least a portion of the electromagnetic radiation incident on the concave reflective surface thereof through the opening formed in the collecting reflector and toward the target.
• the concave reflective surfaces of the collecting and focusing reflectors are preferably parabolic in shape.
• the optical axes of the respective parabolic reflective surfaces are preferably coincident, extending through the openings formed in the collecting and focusing reflectors, and the focal point of the collecting reflector is preferably located proximate the opening formed in the focusing reflector and the focal point of the focusing reflector is preferably located proximate the opening formed in the collecting reflector.
• the device may also include a focusing lens disposed between the collecting and focusing reflectors.
• the focusing lens receives a portion of the electromagnetic radiation transmitted through the opening formed through the focusing reflector and focuses the received electromagnetic radiation through the opening formed in the collecting reflector.
• An electromagnetic source such as a xenon, metal halide, halogen, or mercury arc lamp, may or may not comprise a part of the device.
• a target e.g., the input portion of a wave guide, such as a single optic fiber, a fiber bundle, or a homogenizer of circular or polygonal shape, may or may not comprise a part of the device.
• Figure 1 is a schematic diagram of an ideal paired reflector system for collecting light from a light source and condensing the collected light onto a target with unit magnification.
• Figure 2 is a schematic diagram of a practical paired reflector system including an arc lamp, an output fiber, a retro-reflector, and openings formed in the opposed reflectors for receiving light from the arc lamp and passing light to the output fiber.
• Figure 3 is a schematic diagram illustrating the loss of radiation energy through openings formed in the opposed reflectors for the light source and the output fiber.
• Figure 4 is a schematic diagram illustrating the use of a focusing lens in a paired reflector system for collecting and condensing radiation that would otherwise be lost through openings formed in the reflectors.
• Figure 5 is a schematic diagram of a cascaded system where the outputs of multiple sources are added together for increased brightness at the target.
• Figs. 6A-6G are schematic views of a plurality of polygonal lightguide
• the system 2 includes a first reflector 10 (also known as the collecting reflector) having a concave reflective surface 12 and a second reflector 20 (also known as the condensing, or focusing, reflector) also having a concave reflective surface 22.
• the concave reflective surfaces 12 and 22 are arranged in an opposed-facing relation and are preferably both parabolic in shape.
• the reflective surfaces 12 and 22 may be coated with any suitable reflective material, such as aluminum, silver, or a single or multi-layer dielectric coating for use in various color systems, e.g., a cold mirror for visible light.
• the first reflector 10 has an optical axis 14 on which lies a focal point 16.
• the second reflector 20 has an optical axis 24 on which lies a focal point 26.
• the first reflector 10 and the second reflector 20 are preferably arranged so that their respective optical axes 14 and 24 are coincident with one another.
• a source of electromagnetic radiation 30 is placed at the focal point 16 of the first reflector 10 and a target 32 is placed at the focal point 26 of the second reflector 20.
• Radiation emitted by the source 30 is reflected by the concave reflective surface 12 of the first reflector 10 as collimated rays of radiation toward the concave reflective surface 22 of the second reflector 20. Thereafter, the radiation is again reflected by the concave reflective surface 22 of the second reflector 20 toward the focal point 26 of the second reflector 20 onto target 32 placed at the focal point 26.
• Figure 1 is a schematic view of a cross-section of a paired reflector system.
• the first and second reflectors 10 and 20 are each a paraboloid of revolution.
• the first reflective surface 12 and the second reflective surface 22 are continuous solid surfaces as shown in Figure 1 , it is impractical to introduce the source radiation into the system, and, as well, it is impractical to extract the focused radiation from the closed system.
• Figure 2 shows a practical implementation of the current invention in which the radiation source is an arc lamp 40 placed at the focal point 16 of the first reflector 10, and the target 32 is the input end of a waveguide, such as an output fiber 44, placed at the focal point 26 of the second reflector 20 along the common optical axes 14 and 24 of the reflectors 10 and 20, respectively.
• An opening 28 is formed in the second reflector 20 through which radiation emitted by the lamp 40 enters the region between the opposed reflective surfaces 12 and 22 and impinges on the reflective surface 12 of the first reflector 10. Opening 28 is preferably generally centered about the optical axes 14, 24, which extend through the opening 28.
• Radiation in the form of light emitted by the arc lamp 40 is collected by the first reflector 10, is collimated, and is directed toward the second reflector 20. The light is then reflected by the second reflector 20 and condensed, or focused, onto the target 32 placed at the focal point 26 of the second reflector 20.
• An opening 18 is formed in the first reflector 10 to permit focused light reflected by the reflective surface 22 of the second reflector 20 to escape the region between the reflective surfaces 12, 22 and be incident onto the target 32. Opening 18 is preferably generally centered about the optical axes 14, 24 which extend through the opening 18.
• the first and second reflectors 10, 20 are preferably constructed and arranged so that their respective focal points 16, 26 are located proximate the corresponding opening formed in the opposite reflector.
• a spherical retro-reflector 42 may be placed on the other sides of the arc lamp 40 such that the light emitted from this side of the arc lamp 40 is reflected by the retro- reflector 42 back into the arc lamp itself and subsequently is coupled into the paired reflectors 10, 20, thereby increasing the overall brightness of the output of the system.
• Suitable lamps include xenon, metal halide, halogen, or mercury arc lamps. While a single output fiber 44 is shown in Figure 3, the target may comprise the input end of an output fiber bundle, a homogenizer used for outputting high power to low temperature plastic fibers, or a homogenizer for a projection television.
• Figure 3 A disadvantage of the practical arrangement of Figure 2 is illustrated in Figure 3.
• the opening 18 formed in the first reflector 10 may, of necessity, be larger than the focal point 26 of the second reflector 20 and the target 32, a portion of the radiation emitted by the source 30 that is within a loss cone 46 that subtends the opening 18 will be lost.
• the opening 18 formed in the first reflector 10 effectively takes away the collecting function of the reflector 10 at this area, and the amount of loss can be significant.
• Figure 4 shows the use of a focusing lens 50 disposed between the first and second reflectors 10, 20 and covering the loss cone 46 of light that would have been lost due to the openings 28, 18 of the parabolic reflectors 20, 10, respectively.
• the lens 50 is preferably configured to produce a 1:1 magnification of radiation onto the target located at the focal point 26.
• the target is the input end of a fiber bundle 54.
• the combination of the reflectors 10, 20, and 42 and the focusing lens 50 effectively couples substantially all of the light emitted from the arc lamp 40 onto the target located at the focal point 26.
• the focusing lens 50 may be a conventional, bi- convex lens and can be made from any suitable material, such as plastic, glass, or quartz. Furthermore, an anti-reflective coating may be applied to the external surfaces of the focusing lens 50.
• Figure 4 shows the preferred embodiment including an arc lamp 40 positioned at the opening 28 of the second reflector 20, which is preferably parabolic, a retro-reflector
• the focusing lens 50 has an optical axis that preferably coincides with the optical axes 14 and 24 of the first and second reflectors 10, 20, respectively, and images the focal points 16 and 26 of the first and second reflectors 10 and 20, respectively, in a 1 : 1 manner.
• the remainder of the light emitted by the arc lamp 40 is collected by the first reflector 10 and the retro-reflector 42, is collimated by the first reflector 10 toward the second reflector 20.
• FIG. 5 shows three first, or collecting, reflectors 10a, 10b, and 10c having respective focal points 16a, 16b, 16c, and respective openings 18a, 18b, 18c formed therein.
• the system includes three second, or focusing, reflectors 20a, 20b, 20c having respective focal points 26a, 26b, 26c and respective openings 28a, 28b, 28c formed therein.
• 30b, 30c are positioned at the focal points 16a, 16b, 16c, respectively.
• the retro-reflector 42 may be employed in conjunction with the first source 30a.
• the second and third sources 30b and 30c are located at the focal points 16b and 16c of the reflectors 10b and 10c, respectively.
• These focal points substantially coincide with the focal points 26a and 30a, 30b, 30c located on the common optical axes, are combined and ultimately focused by the third reflector 20c onto the target 60, which, in the illustrated embodiment, comprises a homogenizer, having an input end located at the focal point 26c.
• focusing lenses 50a, 50b, 50c are positioned along the common optical axes between the reflectors 10a and 20a, 10b and 20b, and 10c and 20c, respectively.
• Figure 5 shows a cascaded arrangement including three paired reflector sets and three focusing lenses.
• a cascaded system can comprise only two paired reflector sets or more than three paired reflector sets.
• the homogenizer can be circular (Figure 6 A) or be in the shape of a polygon, such as square ( Figure 6B), a rectangle (Figure 6C), a triangle (Figure 6D), a pentagon (Figure 6E), a hexagon ( Figure 6F), an octagon ( Figure 6G) or any other multi-sided shape.
• the homogenizer can be made of any suitable material, such as plastic, glass, or quartz.

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Optical Elements Other Than Lenses (AREA)
• Lenses (AREA)
• Optical Couplings Of Light Guides (AREA)
• Non-Portable Lighting Devices Or Systems Thereof (AREA)

Priority Applications (5)

Applications Claiming Priority (2)

Publications (1)

Family

ID=22497455

Family Applications (1)

Country Status (7)

Cited By (3)

Families Citing this family (4)

Citations (9)

• 2000
  • 2000-06-23 BR BR0011934-2A patent/BR0011934A/pt not_active Application Discontinuation
  • 2000-06-23 AU AU57607/00A patent/AU5760700A/en not_active Abandoned
  • 2000-06-23 JP JP2001508633A patent/JP2003504662A/ja not_active Withdrawn
  • 2000-06-23 CA CA002377497A patent/CA2377497A1/en not_active Abandoned
  • 2000-06-23 KR KR1020017016901A patent/KR20020033112A/ko not_active Application Discontinuation
  • 2000-06-23 WO PCT/US2000/017265 patent/WO2001002890A1/en not_active Application Discontinuation
  • 2000-06-23 CN CN00809849A patent/CN1359477A/zh active Pending

Patent Citations (9)

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