One-piece multi-lens optical member and method of manufacture

Abstract

A one-piece optical member with a plurality of secondary lenses over corresponding LED light sources, the one-piece optical member comprises (a) each with an outward lens flange surrounding a light-transmitting portion which is formed by a plurality of layers and has an asymmetric inner surface defining a pair of cavities with at least one of the plurality of layers at least partially extending between the pair of cavities, a portion of the inner-surface which defines one of the cavities is at least partially formed by another of the plurality of layers which is bonded to the at least one layer extending between the pair of cavities. The polymeric materials may be different; e.g., the innermost lens layer may be of an LSR material. The invention is also a method of manufacturing the one-piece optical member and an LED light fixture with the one-piece member over a plurality of LED light sources spaced on a circuit board.

Claims

1. An LED light fixture comprising: a heat-sink structure having a mounting surface supporting a circuit board with a plurality of spaced apart LED light sources on the circuit board; and a one-piece optical member over the circuit board and having a carrier portion and a plurality of lenses each with an outward lens flange surrounding a light-transmitting portion which is formed by a plurality of layers and has an asymmetric inner surface defining a pair of cavities with at least one of the plurality of layers at least partially extending between the pair of cavities, a portion of the inner-surface which defines one of the cavities is at least partially formed by another of the plurality of layers which is bonded to the at least one layer extending between the pair of cavities, the carrier portion at least partially overlapping the outward flange of each of the lenses.

2. The LED light fixture of claim 1 wherein: each of the lenses has at least one lens layer of a first polymeric material extending into the lens flange; and the carrier is of a second polymeric material.

3. The LED light fixture of claim 2 wherein the first polymeric material is an acrylic and the second polymeric material is a polycarbonate.

4. The LED light fixture of claim 1 wherein the carrier portion is bonded to the lens flanges across overlapping.

5. The LED light fixture of claim 1 wherein at least two of the lens layers are of the same polymeric material.

6. The LED light fixture of claim 5 wherein the at least two lens layers are of an acrylic.

7. The LED light fixture of claim 1 wherein at least two of the lens layers are of different polymeric materials.

8. The LED light fixture of claim 7 wherein one of the lens layers is an acrylic and at least one other lens layer is of an LSR material.

9. The LED light fixture of claim 1 wherein each of the lenses has three layers of polymeric material.

10. The LED light fixture of claim 9 wherein the three layers are of the same polymeric material.

11. The LED light fixture of claim 9 wherein an innermost polymeric layer is of an LSR material.

12. The LED light fixture of claim 1 wherein the flange is formed by a lens layer forming an outer lens surface.

13. A one-piece optical member comprising: a plurality of spaced lenses positionable over light sources on a circuit board, each of the lenses having an outward flange surrounding a light-transmitting portion which is formed by a plurality of layers and has an asymmetric inner lens surface defining a pair of cavities with at least one of the plurality of layers at least partially extending inwardly between the pair of cavities, a portion of the inner-surface which defines one of the cavities is at least partially formed by another of the plurality of layers which is bonded to the at least one layer extending between the pair of cavities; and a carrier portion bonded to at least a portion of the flange of each of the lenses.

14. The one-piece optical member of claim 13 wherein: each of the lenses has at least one lens layer of a first polymeric material which extends into the lens flange; and the carrier is of a second polymeric material.

15. The one-piece optical member of claim 14 wherein the first polymeric material is an acrylic and the second polymeric material is a polycarbonate.

16. The one-piece optical member of claim 13 wherein the carrier portion is bonded to at least a portion of each of an innermost flange surface facing the circuit board and an opposite outermost flange surface of each lens.

17. The one-piece optical member of claim 13 wherein at least two of the lens layers are of the same polymeric material.

18. The one-piece optical member of claim 17 wherein the at least two lens layers are of an acrylic.

19. The one-piece optical member of claim 13 wherein at least two of the lens layers are of different polymeric materials.

20. The one-piece optical member of claim 19 wherein one of the lens layers is an acrylic and at least one other lens layer is of an LSR material.

21. The one-piece optical member of claim 20 wherein the lens layer of an LSR material is an innermost layer.

22. A method for manufacturing a one-piece optical member having a plurality of spaced lenses positionable over light sources on a circuit board, the method comprising the steps of: providing a plurality of lenses each having a light-transmitting portion surrounded by an outward lens flange, the light-transmitting portion which has an asymmetric inner lens surface defining a pair of cavities with at least one of the plurality of layers at least partially extending between the pair of cavities, a portion of the inner-surface which defines one of the cavities is at least partially formed by another of the plurality of layers which is bonded to the at least one layer extending between the pair of cavities; and bonding a polymeric carrier portion to at least a portion of the flange of each of the plurality of the lenses such that the carrier portion surrounds each of the lenses.

23. The method of claim 22 wherein the step of bonding includes the steps of: placing the plurality of lenses in a mold; and injection molding the polymeric carrier portion onto the lens flanges.

24. The method of claim 23 wherein each of the lens flanges has an indexing feature and the placing of the lenses in spaced positions further includes angularly orienting the lenses in the mold with the indexing features.

25. The method of claim 22 wherein: each of the lenses has at least one lens layer of a first polymeric material; and the carrier is of a second polymeric material.

26. The method of claim 22 wherein the step of providing a plurality of lenses further includes the step of selecting lenses with particular optical properties.

27. The method of claim 26 wherein all of the selected lenses have the same optical properties.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a perspective view of an LED light fixture having two one-piece optical members, such fixture and optical members being in accordance with this invention.

(2) FIG. 1A is a perspective view of a one-piece optical member of the LED lighting fixture of FIG. 1.

(3) FIG. 1B is an enlarged cross-sectional perspective view of one portion of the one-piece optical member of FIG. 1A, illustrating one secondary lens.

(4) FIG. 1C is a perspective view illustrating the positioning of secondary lenses as placed in injection-molding apparatus. The injection-molding apparatus is not shown in FIG. 1C.

(5) FIG. 2 is a perspective view of one such one-piece optical member, showing its light-output side.

(6) FIG. 3 is a perspective view of such optical member, but showing its light-input side.

(7) FIG. 4 is a plan view of such optical member.

(8) FIG. 5 is a side sectional view taken along section 5-5 as indicated in FIG. 4.

(9) FIG. 6 is an end sectional view taken along section 6-6 as indicated in FIG. 4.

(10) FIG. 7 is an enlarged perspective view of the three individual lenses of the one-piece optical member arranged as they would be in a mold prior to the polymeric carrier portion being injection molded onto the lens flanges, to complete the one-piece optical member.

(11) FIG. 8 is a central cross-sectional view of the lens of an alternative embodiment, such alternative lens having three layers.

(12) FIG. 9 is an exploded perspective view of the lens of FIG. 18, serving to illustrate the shapes of the layers of such lens.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(13) FIGS. 1 and 1A-1C illustrate an LED lighting fixture 10 in accordance with this invention. LED light fixture 10 includes a heat-sink structure 12 that has a mounting surface 12A on which a circuit board 14 is mounted. Circuit board 14 has a plurality of LED light sources 14A spaced thereon. A one-piece optical member 16 is positioned over circuit board 14 and has a plurality of secondary lenses 20 thereon, each for alignment with a corresponding one of light sources 14A.

(14) In the improved LED light fixture, each of lenses 20 of one-piece optical member 16 has a layer 22 of polymeric material, which polymeric material extends into a lens flange 24 of such material that surrounds lens 20 and is spaced from lens flanges 24 that surround adjacent lenses 20. One-piece optical member 16 also has a polymeric carrier portion 26 surrounding lenses 20. Carrier portion 26 overlaps with and is molded onto to lens flanges 24 across such overlapping, and carrier portion 26 extends laterally therefrom to a peripheral edge portion 28. FIG. 1B best illustrates the above-described characteristics.

(15) The polymeric material of lens 20, i.e., the material of outer layer 22 and flange 24, is an acrylic, while the polymeric material of carrier portion 26 is a polycarbonate. A wide variety of optical-grade acrylics can be used, and are available from various sources, including: Mitsubishe Rayon America, Inc.; Arkema Group; and Evonik Cyro LLC. Likewise, a wide variety of polycarbonate materials can be used, and are available from various sources, such as Bayer and Sabic.

(16) FIG. 1C illustrates the positioning of secondary lenses 20 as placed in the injection-molding apparatus (not shown). After such placement, carrier portion 26 is injection molded onto lens flanges 24 to form one-piece optical member 16. As already indicated, carrier portion 26 surrounds lenses 20 and overlaps and is molded onto to lens flanges 24.

(17) FIGS. 2-7 illustrate aspects of an alternative one-piece optical member 16A which has three lenses 20 and a carrier portion 26A. The only significant difference between one-piece optical members 16 and 16A is the number of lenses.

(18) FIG. 7, as with FIG. 1C, illustrates the positioning of secondary lenses 20 as placed in the injection-molding apparatus. Accurate placement into the injection-molding apparatus is facilitated by indexing features in the form of posts 30 (see FIGS. 2, 4 and 5) which extend from lens flange 24 and mate with corresponding recesses in the mold. (FIGS. 1A and 1B also show such indexing feature.)

(19) FIGS. 8 and 9 illustrate an alternative lens 40 which is a multi-layer lens. Lens 40 has three layers, including an innermost layer 42, an outermost layer 44, and an intermediate layer 46. The layer shapes are illustrated in the FIG. 14 exploded view. As seen well in FIGS. 8 and 9, lens 40 has an optical footprint, referred to above, and innermost layer 42 is less than coextensive with the lens optical footprint. Outermost layer 44 of lens 40 includes a flange 48 extending beyond the optical footprint of lens 40.

(20) The layers of each pair of adjacent layers of lens 40 are joined together permanently at their interface by overmolding. Lens 40 may be formed by a series of injection-molding steps. For example, innermost layer 42 is first formed by injection molding. Then, at the next injection-molding station, intermediate layer 46 is overmolded with innermost layer 42. And then, at a third injection-molding station, outermost layer 44 is overmolded onto the previously overmolded layers.

(21) The layers of lens 40 may be of the same or differing polymeric materials. And injection-moldable materials may be chosen having different indices of refraction. One or more of the lens layers may be an acrylic and at least one other lens layer may be of an LSR material. In particular, the innermost lens layer may be an LSR material.

(22) While the principles of this invention have been described in connection with specific embodiments, it should be understood clearly that these descriptions are made only by way of example and are not intended to limit the scope of the invention.