Patent Application
20080094852
The LED light source array 12 may be a single LED light source or an array of plural LED light sources. The LED light source array 12 emits light with a distribution about a lamp axis 18, and generally towards a field to be illuminated. The LED light source array 12 is specifically positioned to emit light toward the inner lens 14 and the reflector 16, which are in turn aligned to project light horizontally along a lamp axis 18 towards a field to be illuminated. In the preferred embodiment the LED light source array 12 is a horizontal aligned row of closely spaced LEDs, and in particular a horizontal row of five LEDs each facing axially towards the field to be illuminated.
The inner lens 14 is optically configured to substantially refract light received from the LED light source array 12 to be in or to the lower side of a horizontal plane through the lamp assembly 10. The light transmissive, refractive inner lens 14 is positioned axially and intermediate the LED light source array 12 and the field to be illuminated. The inner lens 14 is positioned roughly in front of the LED light source array 12, and offset from the reflector 16 leaving a surrounding gap 52 between the inner lens 14 and the reflector 16. The inner lens 14 is further sized to intercept a large portion, but less than all of the light emitted by the LED light source array 12. In one embodiment the inner lens 14 was sized and positioned to intercept light emitted from the LED light source array 12 that had a vertical angle 22 about the horizontal (positive and negative) of 45 degrees or less (90 degrees total). The inner lens 14 was similarly sized and positioned to intercept light emitted from the LED light source array 12 that had a horizontal angle 24 about the median (positive or negative) of 60 degrees or less (120 degrees total). The inner lens 14 is optically shaped to refract light received from the LED light source array 12 in a horizontal band 62 extending at or below the horizontal 60. The refracted horizontal band 62 forms a substantial portion of a headlamp beam pattern.
The front surface 34 of the right side end 28 is circularly arced about the LED light source array 12 to approach the reflector 16 in the horizontal plane. The circular arc of the right side end of the front surface may be centered any where along the LED light source array, but is preferably centered at the right side end 29 of the LED light source array. It is understood that while actually centered is ideal, an offset of several LED diameters likely to be the practical range of a functional assembly and therefore is acceptable in defining “centered” here. The rear surface 36 of the right side end 28 may be circularly arced about a point between the right end 29 of the LED light source array 12 and the right end of the front surface 34 of the right side of lens orthogonally projected onto the line of the LED light source array 12, for example, midpoint 38. The right side front surface 34 and rear surface 36 then form a right side lens that spreads light to the right.
The lens 14 is further extended on the right side to approach the reflector 16 in the horizontal plane for attachment. The right side end 28 may include a coupling to latch to the reflector 16 or to extend through a passage formed in the reflector 16 to latch to a support in or behind the reflector 16. For example, an approximately axially extending leg 40 formed with a clip coupling 42 formed on an end of the leg 40 may flexibly latch to a hole in the reflector 16. The extended leg 40 portions of the lens 14 may be formed to be resilient, and thereby sufficiently compressible to spring latch in corresponding receptacles formed in the reflector 16 or a similarly convenient support. The left side end 30 of the lens 14 may be similarly formed.
The front surface 46 of the arced right side (28) of the lens is similarly formed (vertical cross section pivoted from the axis about a point along the LED light source array, such as the end point 29 of the light source array) with an elliptical surface with one foci of the ellipse located at, along or adjacent (roughly centered on) the right side end 29 of the LED light source array 12. In effect, looking at the vertical section, the front optical surface 46 of the central section is dragged around the right side front arc, that is circularly rotated about the LED light source array 12 at the right side end 29 of the lens 14. The preferred left side the lens 14 may be similarly formed (mirrored symmetry).
The reflector 16 has a reflective inner surface 48 defining a cavity 50 with an open end facing along an axis 18 towards the field to be illuminated. The reflector 16 may be molded plastic shell with a metallized reflective surface as is known in the art. The reflector 16 is positioned to surround the inner lens 14, but is offset from the inner lens 14 to provide an optical gap 52 between the inner lens 14 and the reflector 16 through which light emitted by the LED light source array 12 and reflected by the reflector 16 passes. The preferred reflector 16 is sized to intercept a substantial portion, but less than all of the light emitted by the LED light source array 12. The reflector 16 is optically shaped to project light emitted by the LED light source array 12 and intercepted by the reflector 16 in a second pattern different from the first pattern formed by the inner lens 14. Ideally the second pattern is supplementary to the first pattern so the combined patterns form a desired headlamp beam. The preferred reflector 16 is optically shaped to reflect light received from the LED light source array 12 into a supplementary pattern 64 or similar pattern supplementary to the inner lens 14 generated beam pattern, such as the horizontal band 62. The preferred reflector 16 includes one or more optical portions having the form of a section of a paraboloid of revolution 48 that defines a foci. The LED light source array 12 is located at or adjacent the foci. The section of the paraboloid of revolution 48 is oriented to direct light horizontally to form the supplementary beam pattern, such as the supplementary pattern 64 portion of the headlamp beam. It is understood the first pattern and the second pattern may overlap. In the preferred embodiment the reflector 16 includes seven vertical bands, horizontally arrayed, each band being a section of a paraboloid of revolution having a focal point located at or near the light source, thereby yielding a beam pattern spread at or below the horizon line. The preferred seven vertical bands direct light received through the gap 52 between the inner lens 14 and the reflector 16 towards as a supplementary pattern 64 portion of the final beam pattern.
The inner lens 14 then captures the generally forwardly emitted light, perhaps half the emitted LED light, and forms the horizontal spread pattern, emitted from the center or core of the LED light source array 12 beam. The reflector 16 efficiently gathers the generally sideward emitted LED light, and forms the rest of the beam pattern as a sheath coming around the inner lens 14. The reflector 16 generated beam pattern then supplements inner lens 14 generated pattern. Little of the available light is then lost or mis-direct and only one reflection or refraction is need for each emitted ray.
While there have been shown and described what are at present considered to be the preferred embodiments of the invention, it will be apparent to those skilled in the art that various changes and modifications can be made herein without departing from the scope of the invention defined by the appended claims.
The Applicants hereby claim the benefit of their provisional application, Ser. No. 60/854,011 filed Oct. 24, 2006 High Efficiency Automotive LED Optical System.
| Number | Date | Country | |
|---|---|---|---|
| 60854011 | Oct 2006 | US |
