Optic Member for an LED Light Fixture

Abstract

A lens for directing light from an LED light source. The lens is formed by a plurality of layers and has a light-receiving inner-surface defining a pair of cavities. A portion of the inner-surface which defines one of the cavities is at least partially formed by an innermost layer of the plurality of layers. At least a portion of another of the plurality of layers extends inwardly between the pair of cavities. Another aspect of this invention is an optic member including a plurality of the lenses for directing light received from a plurality of spaced apart LED light sources.

Claims

1. An optic member for directing light from a plurality of LED light sources in spaced relationship to one another on a board beneath the optic member, the optic member having a plurality of lenses each for directing light from one of the plurality of LED light sources, the optic member comprising: a first layer of material forming an outermost surface of each of the lenses and a non-lens portion extending from each outermost surface and interconnecting the plurality of lenses; and each of the lenses having a light-receiving inner-surface defining a pair of cavities with at least a portion of a second layer of material extending inwardly between the cavities, a third layer of material at least partially forming a portion of the light-receiving inner-surface which defines one of the cavities.

2. The optic member of claim 1 wherein the first and second layers are of different polymeric materials.

3. The optic member of claim 2 wherein the first layer is an acrylic layer and the third layer is an LSR layer.

4. The optic member of claim 1 wherein the third layer is an innermost layer.

5. The optic member of claim 1 wherein the first layer forms a pocket-space at each lens, the second and third molded polymeric layers being within the corresponding pocket-space.

6. The optic member of claim 1 wherein the third layer is an LSR layer.

7. The optic member of claim 1 wherein at least two of the layers have different indices of refraction.

8. An LED light fixture comprising: a plurality of LED light sources spaced on a mounting surface; and an optic member over the plurality of LED light sources and comprising a plurality of lenses interconnected by a non-lens portion, each of the plurality of lenses having a light-receiving inner-surface which defines a pair of cavities with at least a portion of one optical layer extending inwardly between the cavities and another optical layer at least partially forming a portion of the light-receiving inner-surface which defines one of the cavities.

9. The LED light fixture of claim 8 wherein the layers are of different polymeric materials.

10. The LED light fixture of claim 9 wherein the another layer is an LSR layer.

11. The LED light fixture of claim 10 wherein the another layer is an innermost layer.

12. The LED light fixture of claim 8 wherein the non-lens portion of the optic member is formed by a layer forming a pocket-space at each lens, the other layers being within the corresponding pocket-space.

13. The LED light fixture of claim 8 wherein at least two of the layers have different indices of refraction.

14. A lens for directing light from a light source, the lens being formed by a plurality of layers and comprising an inner surface defining a pair of cavities with at least a portion of one optical layer extending inwardly between the cavities and a portion of the inner surface which defines one of the cavities being at least partially formed by an innermost layer of the plurality of layers.

15. The lens of claim 14 wherein the innermost layer is an LSR layer.

16. The lens of claim 14 wherein at least two of the layers have different indices of refraction.

17. An optic member for directing light received from a plurality of spaced apart LED light sources, the optic member comprising a plurality of lenses each formed by a plurality of polymeric layers, each of the plurality of lenses having an inner-surface defining a pair of cavities with at least a portion of one of the plurality of layers extending inwardly between the cavities and a portion of the inner surface which defines one of the cavities being at least partially formed by an innermost layer of the plurality of layers.

18. The optic member of claim 17 wherein the innermost layer is an LSR layer.

19. The optic member of claim 17 wherein each of the lenses comprises an outermost layer of an acrylic.

20. The optic member of claim 17 wherein at least one pair of the adjacent layers has different indices of refraction.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0026] FIG. 1 is a perspective view of a unitary optic member in accordance with this invention, showing its light-output side.

[0027] FIG. 2 is a perspective view of such unitary optic member, but showing its light-input side.

[0028] FIG. 3 is an enlarged fragmentary sectional perspective view, showing for one lens the first molded polymeric layer and the second molded polymeric layer overmolded onto the first layer within a pocket-space formed in the first molded layer.

[0029] FIG. 4 is a top plan view of such unitary optic member.

[0030] FIG. 5 is a bottom plan view.

[0031] FIGS. 6 and 7 are side elevations taken from two adjacent sides of the unitary optic member.

[0032] FIG. 8 is a side sectional view taken along section 8-8 as indicated in FIG. 4.

[0033] FIG. 9 is a perspective view of the first molded polymeric layer prior to, for each lens portion, the overmolding of the second molded polymeric layer.

[0034] FIG. 10 is an enlarged fragmentary sectional perspective view, as in FIG. 3, but illustrating an embodiment having a third molded polymeric layer as the innermost layer.

[0035] FIG. 11 is a perspective view of the three-layer polymeric lens of FIG. 10, showing its light-output side.

[0036] FIG. 12 is a perspective view of the lens of FIG. 11, but showing its light-input side.

[0037] FIG. 13 is a central cross-sectional view of the lens of FIG. 11, illustrating the three layers of the lens.

[0038] FIG. 14 is an exploded perspective view of such three-layer lens, serving to illustrate the shapes of the layers.

[0039] FIG. 15 is a partially broken-away perspective view of an LED light fixture in accordance with this invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

[0040] Referring in more detail to the drawings of the exemplary embodiments, FIGS. 1-9 illustrate a unitary optic member 10 in accordance with this invention. Unitary optic member 10 has five lens portions 12 which are surrounded by and interconnected by a non-lens portion 14.

[0041] Unitary optic member 10 includes a first molded polymeric layer which forms non-lens portion 14 and the outermost layer 16 of each lens portion 12. Outermost layer 16 of each lens portion 12 forms a pocket-space 18 at such lens portion. For each portion 12, a second molded polymeric layer 20 is overmolded onto the first polymeric layer within corresponding pocket-space 18.

[0042] While the first and second polymeric layers of unitary optic member 10 can be of the same polymeric material, in this embodiment the first and second polymeric layers are of different polymeric materials. More specifically, non-lens portion 14 and outermost layer 16 (of each lens portion 12) is an acrylic, and second polymeric layer 20 is an LSR. A wide variety of optical-grade acrylics can be used, and are available from various sources, including: Mitsubishi Rayon America, Inc.; Arkema Group; and Evonik Cyro LLC. Likewise, a wide variety of optical-grade LSRs can be used, and are available from various sources, such as: The Dow Chemical Company; Wacker Chemie AG; and Momentive Performance Materials Products. Some optical-grade acrylics useful in this invention have an index of refraction of 1.49, and some optical-grade LSR materials have an index of refraction of 1.41.

[0043] The first molded polymeric layer, including its non-lens portion 14 and the outermost layer of each of lens portions 14, is injection-molded, although as noted above other processes to preform such first molded polymeric layer, such as thermoforming, can be used. FIG. 9 illustrates the first molded polymeric member and five pocket spaces 18 which it forms prior to overmolding of second polymeric layer 20 within each of pocket spaces 18. For such overmolding, the first molded polymeric layer is placed in a mold and, for each pocket space 18, lens portions 12 are made by injection molding the second polymeric layer into spaces 18.

[0044] FIG. 3 clearly illustrates outermost layer 16 and second polymeric layer 20 of one of lens portions 12. Such lens portions are two-layered lenses.

[0045] An alternative embodiment in which the lens portions are three-layered lenses is illustrated in FIG. 10, which is a view similar to that of FIG. 3. As can be seen in FIG. 10, the unitary optic member includes a third molded polymeric layer 22 which is overmolded onto second polymeric layer 20, also within corresponding pocket-space 18. Third molded polymeric layer, which is made by a subsequent injection-molding step immediately after the injection molding of second polymeric layer 20, is the innermost layer of the lens portion. Third molded polymeric layer 22 may be of the same polymeric materials as the other two layers, or the layers may have differing polymeric materials, including materials with differing indices of refraction. Third molded polymeric layer 22 may be an LSR layer.

[0046] FIG. 15 illustrates an improved LED light fixture 60 which utilizes two unitary optic members 10 of the type described above. FIG. 15 shows a circuit board 64 which is mounted on a heat sink 62, specifically on a surface thereof for circuit-board mounting. The circuit board has a plurality of LED light sources 64A spaced thereon, and each unitary optic member 10 has lenses 60 each in alignment with a corresponding one of light sources 64A. Unitary optic members 10 are as described in detail above.

[0047] FIGS. 11-14 illustrate another aspect of this invention. Such figures show a multi-layer polymeric lens 40 for directing light from an LED light source. Lens 40 of this embodiment has three layers, including an innermost layer 42, an outermost layer 44, and an intermediate layer 46. This is seen best in FIG. 13, and the layer shapes are illustrated in the FIG. 14 exploded view. As seen well in FIGS. 13 and 14, in lens 40, the optical footprint of the area receiving light from the LED light source by the outer surface of the innermost layer 42 is less than coextensive with the optical footprint of the area receiving light from the LED light source by the inner surface of the intermediate layer 46. The term an optical footprint means a projection on a two-dimensional surface orthogonal to the axis of the LED light source.

[0048] Outermost layer 44 of lens 40 includes a flange 48 extending beyond the optical footprint of lens 40.

[0049] 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.

[0050] The layers of lens 40, as with respect to the layers illustrated best in FIGS. 3 and 10, may be of the same or differing polymeric materials. And injection-moldable materials may be chosen having different indices of refraction.

[0051] 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.