Optics for illumination devices
Optics are provided for use in illumination devices the optics having a light guide, a redirecting layer including a plurality of lenses, and a plurality of reflector elements. Light from a light source enters the light guide and is guided therein until it escapes into a reflector element, which reflects at least some of the light received by the reflector element toward a corresponding lens for emission from the illumination device.
1. An optic for use with a light source in an illumination device, the optic comprising:
a light guide made of light transmissive material, the light guide comprising
a first surface;
a second surface opposite the first surface;
a light coupling area for receiving light from the light source; and
a peripheral edge;
a redirecting layer made of light transmissive material, the redirecting layer comprising a plurality of lenses in optical communication with the light guide for emitting light, the redirecting layer being optically attached to the first surface of the light guide; and
a plurality of reflector elements adjacent and optically connected to the second surface of the light guide, each reflector element being associated with a lens of the redirecting layer for ejecting light entering the reflector element from the light guide toward the associated lens, wherein each of the reflector elements comprises an inter-step portion to receive light from the light guide, a first portion to reflect light towards the associated lens, and a second portion to reflect light from the inter-step portion to the first portion;
the reflector elements comprising a light transmissive material of lower refractive index than the material of the light guide, the reflector elements being arranged such that said material is adjacent to the light guide.
2. The optic of claim 1 where the light guide is made from a material selected from the group of glass, polycarbonate, injection molded poly(methyl methacrylate) (PMMA), injection molded polymethyl methacrylimide (PMMI), cyclo olefin polymers (COP), cyclo olefin copolymers (COC), and silicone.
3. The optic of claim 1 where the first surface is a planar surface.
4. The optic of claim 1 where the plurality of lenses of the redirecting layer is planocovenx lenses that are adjacent to one another.
5. The optic of claim 1 where the redirecting layer is integrated or over molded with the first surface of the light guide.
6. The optic of claim 1 wherein the reflector elements comprise flat, parabolic analytical or free-form reflective surfaces.
7. The optic of claim 1 wherein light is totally internally reflected by the first surface of the light guide and a step portion of the second surface of the light guide.
8. The optic of claim 1 wherein the first surface of the light guide is sloped relative to the light emitting surface of the redirecting layer and the redirecting layer is wedgedshape in cross-section so that the combined thickness of the redirecting layer and light guide is substantially constant.
9. The optic of claim 1 further comprising an optical coupling layer between the redirecting layer and the light guide, wherein the optical coupling layer is made from a heat-deformable, optically transmissive material and the redirecting layer and the light guide are fused together into a monolithic optic.
10. The optic of claim 1 further comprising a low refractive index film between a reflector element and the light guide whereby light entering the reflective element via the inter-step portion and reflected by the second portion of the reflective surface of the reflector element undergoes total internal reflection at the interface of the low refractive index film and the reflector element.
11. The optic of claim 1 wherein the second portion of the reflector element comprises a protrusion extending from a substantially flat portion whereby light from the light guide passes through an optical aperture formed by the protrusion and the reflector element.
12. The optic of claim 1 wherein the redirecting layer comprises a plurality of concavo-convex lenses; and the second surface of the optic is stepped.
13. An illumination device comprising
an optic of claim 1 ;
a light source coupled to the light coupling area of the optic.
14. The illumination device of claim 13 wherein the illumination has a circulate symmetry about a central axis passing through the light source for the optic.
15. The illumination device of claim 13 wherein the illumination device is planar cuboid has a linear light source and plane of symmetry about the light source.
16. An optic for use with a light source in an illumination device, the optic comprising:
an array of redirecting lenses and associated reflector elements;
a light guide made of light transmissive material having a first surface optically attached to the redirecting lenses and a second substantially parallel surface optically attached to the reflector elements, the light transmissive material of the light guide having a higher index of refraction than a light transmissive material present in at least one of the redirecting lenses and the reflector elements;
a light conditioning element for receiving light from a light source for distributing light within the light guide;
each of the reflector elements comprising an inter-step portion for receiving light from the light guide, a first portion for reflecting light towards the associated lens, and a second portion for reflecting light from the inter-step portion to the first portion;
the redirecting lenses transmitting received light to the exterior of the optic.
17. The optic of claim 16 wherein the redirecting lenses and the reflector elements are integrally formed with the light guide.