HK1140171A - An improved led device for wide beam generation and method of making the same - Google Patents

Description

Improved LED device for generating a wide beam and method of manufacturing the same

RELATED APPLICATIONS

The present application relates to the following patent applications: U.S. patent application serial No. 11/711,218 filed on 26.2.2007; U.S. provisional patent application serial No. 60/777,310 filed on 27/2/2006; U.S. provisional patent application serial No. 60/838,035 filed on 8/15 2006; U.S. provisional patent application serial No. 60/861,789 filed on 29.2006, 11/29; U.S. provisional patent application serial No. 60/939,275, filed on 21/5/2007. The above-mentioned patent applications are all incorporated herein by reference and the priority of the above-mentioned patent applications is claimed in accordance with 35USC 119.

Technical Field

The invention relates to the following fields: apparatus and methods for generating a predetermined wide profile two-dimensional illumination pattern using Light Emitting Diodes (LEDs) or other light sources; either a light source that has been optically tuned to provide a corresponding wide profile beam or a planar array of a plurality of such tuned light sources is used.

Background

The initial investment cost of LED lighting is expensive, measured in cost per lumen of use, compared to conventional lighting fixtures. Although this may change over time, this high cost creates additional expense in the collection and distribution efficiency (collection and distribution efficiency) of the LED optical system. The higher the system efficiency, the better the cost-benefit (cost-benefit) of LED lighting compared to traditional lighting fixtures such as incandescent, fluorescent, neon lights.

One conventional solution for generating a broad beam (broad beam) with an LED is: one or more reflectors and/or lenses are used to harvest the energy of the LEDs and then expand it into the desired beam shape (beam shape) and provide an angled array of such LEDs mounted on a curved fixture (texture). For example, street light illumination patterns are conventionally defined into five categories: types I to V. Type I is an elongated (oblong) pattern on the street with a light located over the center of the elongated. Type II is a symmetric four lobe pattern with the lamp located over the center of the lobe pattern. Type III is a flat elongated pattern with the lamp near the flat side of the elongated pattern. Type IV is parabolic pattern with a flat bottom, where the lamp is close to the flat bottom. Type V is a circular pattern with the lamp located above the center of the circle. Any asymmetric aspect (aspect) of these types of patterns can be obtained by mounting the light source in a curved holder (array) or fixture. By bending or angling the fixture, the LEDs or light sources are directed in the desired direction to create a broad or expanded beam on a surface such as a street, where a portion of the light must be directed upwards away from the street and towards the sky.

All aircraft passengers are therefore familiar with the view of an illuminated city when landing at night. This often dazzling view is largely due to street lights, and more specifically, street lights that have angled fixtures to produce an expanded beam that collectively directs a large amount of light into the sky. In an effectively illuminated city, the city would appear much dimmer to the aircraft, as its street lights should only shine on the street, not into the sky. Dazzling city lights seen from aircraft and mountaintops can be romantic, but also represent a huge energy loss, unnecessary fuel usage, and tons of unnecessary greenhouse gas emissions from power plants needed to generate electrical energy for this useless misdirected light.

The other technology is as follows: collimating lenses and/or reflectors and sheet optics (sheetoptic) such as those manufactured by Physical Devices Corporation are used to spread the energy into the desired beam. The reflector has a predetermined surface loss based on the metallization (metalizing) technique utilized. Lenses that are not coated with an anti-reflective coating also have surface losses associated with the metallization technique utilized. Sheet materials from physical devices Corporation have a loss of about 8%.

One example of a near-efficient system of the prior art is the "side emitter" device sold by Lumileds as part of its LED assembly (packaging) offering. But "side emitter" is intended to produce a beam having a generally 90 degree radial pattern rather than a forward beam. Its internal loss was estimated to be 15%. Another LED by Lumileds, commonly referred to as a low dome or batwing LED, has a lens on its LED housing to redirect light, but it should be noted that the lens does not have an undercut (undercut) surface for redirecting light from the LED in a peripheral forward solid angle. Similarly, it should be noted that for a conventional 5mm dome lens (dome lens) or an assembly provided for an LED, the dome is completely free of any undercut surface.

What is needed is an apparatus for generating a wide angle beam, and possibly even a radially asymmetric beam, that can be generated using a design method that allows a designer to achieve a smooth beam profile without the inherent drawbacks of the prior art.

Disclosure of Invention

Exemplary embodiments of the present invention include a method of providing a predetermined illuminated surface pattern from a predetermined energy distribution pattern of an LED light source within an LED housing having a light transmitting dome. The method comprises the following steps: defining an estimated optical transfer function (estimated optical transfer function) for a lens shape of an optic having potentially refractive outer and inner surfaces that at least partially surround a light transmissive dome of the LED housing; generating an energy distribution pattern from a predetermined energy distribution pattern of the light source using the estimated optical transfer function of the lens shape; generating a projection of the energy distribution pattern onto the illuminated surface; comparing the projection of the energy distribution pattern to the predetermined illuminated surface pattern; adjusting (modify) the estimated optical transfer function of the lens shape; and repeating the aforementioned steps of generating an energy distribution pattern from a predetermined energy distribution pattern of the light source using an estimated optical transfer function comprising a lens shape of an inner surface of the optic, generating a projection of the energy distribution pattern onto the illuminated surface, and comparing the projection of the energy distribution pattern with the predetermined illuminated surface pattern until an acceptable correspondence is obtained between the projection of the energy distribution pattern and the predetermined illuminated surface pattern. A lens is then fabricated that includes the shaped (shaped) inner surface of the optic with the estimated optical transfer function ultimately obtained.

In embodiments where the LED housing is placed within a well in a carrier, the step of defining an estimated optical transfer function of the lens shape of the optical device comprises the steps of: positioning and configuring an inner surface of the optic to direct light out of the well; if not redirected, the light would otherwise be intercepted by the well (interrupt).

In another embodiment, the step of defining an estimated optical transfer function of the lens shape of the optical device comprises the steps of: the inner surface of the optic is positioned and configured to direct light in a direction that meets the needs of a user-defined system.

While certain apparatus and methods have or will be described for the sake of grammatical fluidity with functional explanations, it is to be expressly understood that the claims are not to be construed as necessarily limited in any way by the construction of "means" or "steps" unless expressly specified by the 35USC112, but rather are to be accorded the full scope of the meaning and equivalents of the definition provided by the claims under the judicial doctrine of equivalents; where 35USC112 expressly specifies, the claims should be accorded full statutory equivalents of 35USC 112. The invention may now be better understood by reference to the following drawings, in which like elements are identified by like reference numerals.

Drawings

Fig. 1 is a side sectional view of the exemplary embodiment.

The invention and its various embodiments, which are presented as examples of the invention defined by the claims, may now be better understood by reference to the following detailed description of the preferred embodiments. It should be expressly understood that the invention as defined by the claims may be broader than the exemplary embodiments.

Detailed Description

As a further improvement of the blob lens(s) or optic generally designated by reference numeral 10 in fig. 1, in combination with the LED housing 1 described in the various incorporated applications mentioned above, fig. 1 is directed to another embodiment showing a side cross-sectional view of a radially symmetric (Lambertian) blob optic 10 depicting a planar light trace of an approximately Lambertian LED source 12. The dome 14 of the LED housing 1 is shown as approximately hemispherical. Dome 14 is disposed within a cavity defined in optical device 10. There is an air gap, or at least a region 26 of differential refractive index, so that the inner surface 4 of the optic 10 radially surrounds the potentially refractive surface of the dome 14. Whether region 26 is considered to have this defined refractive surface or inner surface 4 of optic 10 is considered to be this defined surface, it is not important because it is the refractive surface that is defined by the refractive index discontinuity at the common boundary of region 26 and optic 10. By adjusting the inner surface 4 of the blob optic 10, the set of rays (ray set) from the LED source 12 can be adjusted to suit the needs of a user-defined system, which may vary from application to application.

For example, in the illustration of fig. 1, the LED source 12 and the housing 1 are disposed in a well 20 defined in a carrier 18, wherein the LED source 12 is located below the level of an upper surface 22 of the carrier 18. The drop optic 10 is also shown mounted in a well 20 and extending below the level of the surface 22.

Fig. 1 shows that light rays 3 from the LED source 12, which radiate 90 degrees from the vertical centerline 16 of the LED source 12, if not redirected by the inner surface 4, will miss the outer surface 2 of the blob optic 10, either being lost or not available for any kind of useful application. Of course, this is true not only for light ray 3, but also for all light rays that are typically located in the lower (lower) peripheral solid angle of the forward hemispherical radiating pattern of the LED housing 1, which is intercepted by the inner walls of the well 20 up to the surface 22.

To avoid the loss of this energy component of the output or light beam caused by the combination of the optic 10 and the LED housing 1, the inner surface 4 of the optic 10 is curved inwardly along a lower periphery or skirt (skirt)24 to create a refractive region 26 between the dome 14 and the inner surface of the optic 10 that flares radially outwardly to refract intercepted light from the LED housing 1 to a portion of the outer surface 2 of the optic 10 above the level of said surface 22. In the exemplary embodiment, the flared skirt 24 of the surface 4 is azimuthally symmetric (azimuthally symmetry) about the LED source 12. It is well within the scope of the present invention, however, that the flared portion 24 may have a shape that varies with azimuth.

By making other shape adjustments to the inner surface 4, additional effects can be expected. For example, not only the intercepted light from the LED housing 1 that is selected to be redirected, but any portion of the radiated light from the LED housing 1 can be optically processed by a curved or shaped (shaped) portion of the inner surface 4 of the optic 10 to redirect that portion of the light to a selected portion of the outer surface 2 of the optic 10 to meet the needs of a user-customized system desired in any given application. For example, it is often the case that it is necessary to redirect light on or near the axis 16 of the LED housing 1 to a different angle with respect to the axis 16, i.e. away from the central light beam towards the periphery or towards a selected peripheral direction. In this case, the inner surface 4 will have a varying (altered) shape at its upper crown 28, adjacent or near the axis 16, to refract the central axis light from the LED housing 1 to the desired direction or directions. For example, inner surface 4 may be formed such that light rays incident on a portion of surface 4 on one side of an imaginary vertical plane containing axis 16 are directed toward an opposite side of the imaginary vertical plane or through optical device 10.

It should be expressly understood that the examples of additional optical effects do not limit the scope or spirit of the present invention-the present invention contemplates all possible optical effects achieved by adjusting the inner surface 4, either alone or in combination with the associated adjustment of the outer surface 2 of the optical device 10.

In summary, an exemplary embodiment of the present invention is a method of providing a predetermined illuminated surface pattern from a predetermined energy distribution pattern of an LED light source within an LED housing having a light transmitting dome. The method comprises the following steps: defining an estimated optical transfer function of a lens shape of an optic having potentially refractive outer and inner surfaces at least partially enclosing a light transmissive dome of the LED housing; generating an energy distribution pattern from a predetermined energy distribution pattern of the light source using the estimated optical transfer function of the lens shape; generating a projection of the energy distribution pattern onto the illuminated surface; comparing the projection of the energy distribution pattern to the predetermined illuminated surface pattern; adjusting the estimated optical transfer function of the lens shape; and repeating the aforementioned steps of generating an energy distribution pattern from a predetermined energy distribution pattern of the light source using an estimated optical transfer function comprising a lens shape of an inner surface of the optic, generating a projection of the energy distribution pattern onto the illuminated surface, and comparing the projection of the energy distribution pattern with the predetermined illuminated surface pattern until an acceptable correspondence is obtained between the projection of the energy distribution pattern and the predetermined illuminated surface pattern.

The method further includes fabricating a lens comprising a shaped inner surface of the optical device with a resulting estimated optical transfer function. The manufacturing method includes all modes of construction (modes of construction) that are currently known or that will be made later. For example, once an acceptable transfer function for the optic is determined according to the above steps, the shape of the outer and inner surfaces of the optic is fully defined. The optical device is typically molded from a transparent plastic or an optical plastic or polymer.

In this exemplary embodiment, the repeated steps generate a projection of an energy distribution pattern onto the illuminated surface that conforms to a predetermined street light illumination pattern, or more specifically, conforms to one of street light illumination pattern types I-V.

In most practical embodiments, a plurality of LED light sources are combined, so the following steps are repeated for each of the plurality of LED light sources: defining an estimated optical transfer function; generating an energy distribution pattern; generating an energy distribution pattern projection, comparing the energy distribution pattern projections; and adjusting the estimated optical transfer function of the lens shape.

In addition, in most practical embodiments, the LED light sources are mounted in a fixture, or in a carrier which in turn is mounted in a fixture. Repeating the following steps for each of the plurality of LED light sources, taking into account the position and orientation of each LED light source in the fixture or in the carrier in the fixture: defining an estimated optical transfer function; generating an energy distribution pattern; generating a projection of the energy distribution pattern; comparing the projections of the energy distribution patterns; and adjusting the estimated optical transfer function of the lens shape.

Typically, in many installations, the LED housing is placed within a well defined in a carrier, and the step of generating the energy distribution pattern using the estimated optical transfer function of the lens shape therefore comprises: generating an energy distribution pattern in which a portion of light is directed out of the well without impinging light from the LED light source onto the well, the portion of light emanating from the LED light source into at least a portion of a forward hemispherical solid angle centered on the LED light source; if not repositioned, this portion of light would otherwise impinge on some portion of the well. The step of directing a portion of the light out of the well comprises: this portion of the light is directed out of the well using an inwardly flared skirt on the inner surface of the optic.

In general, the step of generating an energy distribution pattern using an estimated optical transfer function of the lens shape comprises: an energy distribution pattern is generated in which light is directed in a pattern to meet the needs of a user-defined system.

In another embodiment, the step of generating the energy distribution pattern using the estimated optical transfer function of the lens shape comprises: an energy distribution pattern is generated in which light is directed through the outer surface of the optic from where it is refracted by the outer surface toward the opposite side of the optic.

In addition to the methods disclosed above, the exemplary embodiments expressly include the optics provided by these methods as such, or a fixture or carrier containing a plurality of such optics and their LED light sources.

Many alterations and modifications may be made by those having ordinary skill in the art without departing from the spirit and scope of the invention. Accordingly, it must be understood that the illustrated embodiments have been set forth only for the purposes of example, and that it should not be taken as limiting the invention as defined by the following claims. For example, although the following claims element(s) in a certain combination are set forth below, it should be expressly understood that the invention includes other combinations of fewer, more or different elements, which are disclosed in above even when not initially claimed in such combinations.

The words used in this specification to describe the invention and its various embodiments are to be understood not only in the sense of their commonly defined meanings, but to include by special definition in this specification structure, material or acts beyond the scope of the commonly defined meanings. Thus, if an element can be understood in the context of this specification as including more than one meaning, then its use in a claim must be understood as being generic to all possible meanings supported by the specification and by the word itself.

The definitions of the words or elements of the following claims are, therefore, defined in this specification to include not only the combination of elements which are literally set forth, but all equivalent structure, material or acts for performing substantially the same function in substantially the same way to obtain substantially the same result. Thus, the following are expected in this sense: two or more elements may be equivalently replaced by any element in the claims or two or more elements may be replaced by a single element in a single claim. Although elements may be described above as acting in certain combinations and even initially claimed as such, it is to be expressly understood that one or more elements from a claimed combination can in some cases be excised from the combination and that the claimed combination may be directed to a subcombination or variation of a subcombination.

Insubstantial changes from what is currently known or later come to be viewed by a person with ordinary skill in the art to the claimed subject matter are expressly contemplated as being equivalently within the scope of the claims. Thus, obvious substitutions now or later known to one with ordinary skill in the art are defined to be within the scope of the defined elements.

The claims are thus to be understood to include what is specifically illustrated and described above, what is conceptually equivalent, what can be obviously substituted and also what essentially incorporates the essential idea of the invention.

Claims (21)

1. A method of providing a predetermined illuminated surface pattern from a predetermined energy distribution pattern of an LED light source within an LED housing having a light transmitting dome, comprising:

defining an estimated optical transfer function of a lens shape of an optic having potentially refractive outer and inner surfaces at least partially encasing a light transmissive dome of the LED package;

generating an energy distribution pattern from a predetermined energy distribution pattern of the light source using an estimated optical transfer function of a lens shape;

generating a projection of the energy distribution pattern onto an illuminated surface;

comparing the projection of the energy distribution pattern to the predetermined illuminated surface pattern;

adjusting the estimated optical transfer function of the lens shape; and

repeating the aforementioned steps of generating an energy distribution pattern from a predetermined energy distribution pattern of a light source using an estimated optical transfer function comprising a lens shape of an inner surface of an optical device, generating a projection of said energy distribution pattern onto an illuminated surface, and comparing said projection of said energy distribution pattern with said predetermined illuminated surface pattern until an acceptable correspondence between said projection of said energy distribution pattern and said predetermined illuminated surface pattern is obtained.

2. The method of claim 1, further comprising fabricating a lens comprising a shaped inner surface of the optical device with a resulting estimated optical transfer function.

3. The method of claim 1, wherein the repeated steps generate a projection of the energy distribution pattern onto the illuminated surface that conforms to a predetermined street light illumination pattern.

4. The method of claim 1, wherein the repeated steps generate a projection of the energy distribution pattern onto the illuminated surface that conforms to one of street light illumination pattern types I-V.

5. The method of claim 1, wherein the LED light source is a plurality of LED light sources, and wherein the following steps are repeated for each of the plurality of LED light sources: defining an estimated optical transfer function, generating an energy distribution pattern, generating a projection of the energy distribution pattern, comparing the projections of the energy distribution pattern, and adjusting the estimated optical transfer function of the lens shape.

6. The method of claim 1, wherein the LED light source is a plurality of LED light sources in a fixture, and wherein the following steps are repeated for each of the plurality of LED light sources in view of the position and orientation of each LED light source in the fixture: defining an estimated optical transfer function, generating an energy distribution pattern, generating a projection of the energy distribution pattern, comparing the projections of the energy distribution pattern, and adjusting the estimated optical transfer function of the lens shape.

7. The method of claim 6, wherein the plurality of LED light sources are arranged in a carrier mounted in a fixture, and wherein the following steps are repeated for each of the plurality of LED light sources in view of the position and orientation of each LED light source in the carrier in the fixture: defining an estimated optical transfer function, generating an energy distribution pattern, generating a projection of the energy distribution pattern, comparing the projections of the energy distribution pattern, and adjusting the estimated optical transfer function of the lens shape.

8. The method of claim 1, wherein the LED housing is disposed within a well defined in a carrier, and wherein generating an energy distribution pattern using an estimated optical transfer function of a lens shape comprises: generating an energy distribution pattern in which a portion of light emitted from the LED light source is directed out of a well without impinging light from the LED light source onto the well into at least a portion of a forward hemispherical solid angle centered on the LED light source; if not redirected, this portion of the light would otherwise impinge on some portion of the well.

9. The method of claim 8, wherein directing a portion of the light out of the well comprises: this portion of the light is directed out of the well using an inwardly flared skirt on the inner surface of the optic.

10. The method of claim 1, wherein generating an energy distribution pattern using the estimated optical transfer function of the lens shape comprises: an energy distribution pattern is generated in which light is directed in a pattern to meet the needs of a user-defined system.

11. The method of claim 1, wherein generating an energy distribution pattern using the estimated optical transfer function of the lens shape comprises: an energy distribution pattern is generated in which light is directed through the outer surface of the optic from where it is refracted by the outer surface toward an opposite side of the optic.

12. An optic for providing a predetermined illuminated surface pattern from a predetermined energy distribution pattern of an LED light source within an LED housing having a light transmitting dome, the optic comprising potentially refractive outer and inner surfaces at least partially encasing the light transmitting dome of the LED housing, the outer and inner surfaces defining an estimated optical transfer function that, when combined with the predetermined energy distribution pattern of the LED light source, generates an energy distribution pattern; deriving from the energy distribution pattern a projection of the energy distribution pattern onto an illuminated surface, wherein the outer and inner surfaces are defined by comparing the projection of the energy distribution pattern with a predetermined illumination surface pattern; adjusting the estimated optical transfer functions of the outer and inner surfaces; and repeating the aforementioned steps of generating an energy distribution pattern to generate a projection of the energy distribution pattern and comparing the projection of the energy distribution pattern to the predetermined illuminated surface pattern until an acceptable correspondence is obtained between the projection of the energy distribution pattern and the predetermined illuminated surface pattern.

13. The optical device of claim 12, wherein the outer and inner surfaces together provide a projection of the energy distribution pattern onto the illuminated surface that conforms to a predetermined street light illumination pattern.

14. The optic of claim 12, wherein the outer and inner surfaces together provide a projection of the energy distribution pattern onto the illuminated surface that conforms to one of street light illumination pattern types I-V.

15. The optic of claim 12, wherein the LED light source is a plurality of LED light sources each having a respective optic, and wherein outer and inner surfaces of the plurality of LED light sources collectively define an estimated optical transfer function, an energy distribution pattern, and a projection of the energy distribution pattern with acceptable consistency with the predetermined illuminated surface pattern.

16. The optic of claim 12, wherein the LED light source is a plurality of LED light sources each having a respective optic disposed in a fixture, and wherein the outer and inner surfaces of the plurality of LED light sources collectively define an estimated optical transfer function, an energy distribution pattern, and a projection of the energy distribution pattern with acceptable consistency with the predetermined illumination surface pattern, taking into account the position and orientation of each LED light source in the fixture.

17. The optical device of claim 16, wherein the plurality of LED light sources are disposed in a carrier mounted in a fixture, and wherein the outer and inner surfaces of the plurality of LED light sources collectively define an estimated optical transfer function, an energy distribution pattern, and a projection of the energy distribution pattern with acceptable consistency with the predetermined illumination surface pattern, taking into account the position and orientation of each LED light source in the carrier in the fixture.

18. The optic of claim 12, wherein the LED housing is positioned within a well defined in a carrier, and wherein the outer and inner surfaces provide an energy distribution pattern in which a portion of light emitted from the LED light source enters at least a portion of a forward hemispherical solid angle centered on the LED light source is directed out of the well without impinging light from the LED light source onto the well; if not redirected, this portion of the light would otherwise impinge on some portion of the well.

19. The optic of claim 18, wherein an inwardly flared skirt on an inner surface of the optic directs the portion of light out of the well.

20. The optic of claim 12, wherein the outer and inner surfaces generate an energy distribution pattern in which light is directed in a pattern to meet the needs of a user-defined system.

21. The optic of claim 12, wherein the outer and inner surfaces provide an energy distribution pattern in which light is directed through the outer surface of the optic toward an opposite side of the optic from where it is refracted by the outer surface.