Light fixture and lens assembly for same
First Claim
1. A lens assembly for directing light emitted from a light source toward an area to be illuminated, the light source being elongated along a light source longitudinal axis, the lens assembly comprising:
- an elongate lens extending along a lens longitudinal axis parallel to said light source longitudinal axis and having a central lens portion curved in a plane transverse to the lens longitudinal axis that defines a prismatic face that is oriented toward and spaced from said light source and an opposed, substantially smooth, exterior surface; and
a means for generating a plurality of spaced elongate stripes of reduced brightness to control high angle glare in the longitudinal direction optically, comprising a plurality of adjoining elongate prismatic elements formed on the prismatic face of the central lens portion that extend parallel to said lens longitudinal axis, wherein each prismatic element has a curved surface facing said light source, wherein each pair of adjoining elongate prismatic elements form a common elongate cusp edge, wherein each elongate prismatic element of the plurality of adjoining elongate prismatic elements is configured such that a reverse ray impacting the elongate prismatic element proximate the common cusp edge at an angle of incidence ω
of at least about 40°
will undergo total internal reflection and be reflected back into the area to be illuminated to form a stripe of reduced brightness on the exterior surface of the lens, and wherein each stripe of reduced brightness extends substantially parallel to the lens longitudinal axis.
2 Assignments
0 Petitions
Accused Products
Abstract
A light fixture or troffer for directing light emitted from a light source toward an area to be illuminated, including a reflector assembly within which the light source is positioned and a lens assembly detachably secured to a portion of the reflector assembly such that a lens of the lens assembly overlies the light source and such that substantially all of the light emitted from the light source passes through the lens assembly. In one example, the lens includes a curved prismatic surface that can be oriented toward or away from the underlying light source.
156 Citations
67 Claims
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1. A lens assembly for directing light emitted from a light source toward an area to be illuminated, the light source being elongated along a light source longitudinal axis, the lens assembly comprising:
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an elongate lens extending along a lens longitudinal axis parallel to said light source longitudinal axis and having a central lens portion curved in a plane transverse to the lens longitudinal axis that defines a prismatic face that is oriented toward and spaced from said light source and an opposed, substantially smooth, exterior surface; and a means for generating a plurality of spaced elongate stripes of reduced brightness to control high angle glare in the longitudinal direction optically, comprising a plurality of adjoining elongate prismatic elements formed on the prismatic face of the central lens portion that extend parallel to said lens longitudinal axis, wherein each prismatic element has a curved surface facing said light source, wherein each pair of adjoining elongate prismatic elements form a common elongate cusp edge, wherein each elongate prismatic element of the plurality of adjoining elongate prismatic elements is configured such that a reverse ray impacting the elongate prismatic element proximate the common cusp edge at an angle of incidence ω
of at least about 40°
will undergo total internal reflection and be reflected back into the area to be illuminated to form a stripe of reduced brightness on the exterior surface of the lens, and wherein each stripe of reduced brightness extends substantially parallel to the lens longitudinal axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A lens assembly for directing light emitted from a light source toward an area desired to be illuminated, the light source being elongated along a light source longitudinal axis, the lens assembly comprising:
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an elongated lens having a first end edge, an opposed second end edge, a central lens portion that extends between the first and second end edges, and a lens longitudinal axis that is generally parallel to the light source longitudinal axis, the central lens portion being curved in a plane transverse to the light source longitudinal axis and being symmetric about a plane that extends through the light source longitudinal axis, wherein the central lens portion having a prismatic surface that defines a face oriented toward and spaced from the light source and an opposed, substantially smooth, exterior surface; and a means for generating a plurality of spaced elongate stripes of reduced brightness to control high angle glare in the longitudinal direction optically, comprising an array of linearly extending prismatic elements, each prismatic element thereof extending generally longitudinally substantially between the first and second end edges of the lens, wherein each prismatic element has a curved surface facing said light source, wherein each pair of adjoining elongate prismatic elements form a common elongate cusp edge, wherein each elongate prismatic element of the plurality of adjoining elongate prismatic elements is configured such that a reverse ray impacting the elongate prismatic element proximate the common cusp edge at an angle of incidence ω
of at least about 40°
will undergo total internal reflection and be reflected back into the area to be illuminated to form a stripe of reduced brightness on the exterior surface of the lens, and wherein each stripe of reduced brightness extends generally longitudinally substantially between the first and second end edges of the lens. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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36. A light fixture for directing light toward an area desired to be illuminated, comprising:
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a reflector assembly comprising an elongated base member having a base longitudinal axis; a linear light source for generating the light, the light source being elongated along a light source longitudinal axis and being operatively supported by the base member; and a lens assembly comprising; a) an elongated lens having a curved central lens portion that extends generally parallel to the light source longitudinal axis and is symmetric about a plane that extends through the light source longitudinal axis, the central lens portion having an substantially smooth exterior surface and an opposed prismatic surface that defines a concave face spaced from and facing the light source, wherein the lens assembly is constructed and arranged for detachable connection to a portion of the base member of the reflector assembly; and b) a means for generating a plurality of spaced elongate stripes of reduced brightness to control high angle glare in the longitudinal direction optically comprising a plurality of adjoining elongate prismatic elements formed on the prismatic surface of the central lens portion that extend generally longitudinally parallel to said lens longitudinal axis, wherein each prismatic element has a curved surface facing away from said light source, wherein each pair of adjoining elongate prismatic elements form a common elongate cusp edge, wherein each elongate prismatic element of the plurality of adjoining elongate prismatic elements is configured such that a reverse ray impacting the elongate prismatic element proximate the common cusp edge at an angle of incidence ω
of at least about 40°
will undergo total internal reflection and be reflected back into the area to be illuminated to form a stripe of reduced brightness on the exterior surface of the lens, and wherein each stripe of reduced brightness extends substantially parallel to the lens longitudinal axis. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60)
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61. A method of controlling light emitted at angles close to a ceiling plane, comprising:
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a. mounting a light fixture substantially parallel to the ceiling plane, the light fixture comprising; i) a reflector assembly comprising an elongated base member having a base longitudinal axis, a first longitudinally extending side edge, and an opposed second longitudinally extending side edge; ii) a light source for generating the light, the light source being elongated along a light source longitudinal axis, the light source being operatively connected to the base member; iii) a lens assembly comprising an elongated lens having a lens longitudinal axis and a central lens portion that is curved in a plane transverse to the lens longitudinal axis, the central lens portion extending generally parallel to the light source longitudinal axis and symmetric about a plane that extends through the light source longitudinal axis, the central lens portion having a prismatic surface that defines a face spaced from and facing the light source and an opposed, substantially smooth, exterior surface; and iv) a means for generating a plurality of spaced elongate stripes of reduced brightness to control high angle glare in the longitudinal direction optically, comprising a plurality of adjoining elongate prismatic elements formed on the face of the central lens portion that extend parallel to said lens longitudinal axis, wherein each prismatic element has a curved surface facing said light source, wherein each pair of adjoining elongate prismatic elements form a common elongate cusp edge, wherein each elongate prismatic element of the plurality of adjoining elongate prismatic elements is configured such that a reverse ray impacting the elongate prismatic element proximate the common cusp edge at an angle of incidence ω
of at least about 40°
will undergo total internal reflection and be reflected back into the area to be illuminated to form a stripe of reduced brightness on the exterior surface of the lens, and wherein each stripe of reduced brightness extends substantially parallel to the lens longitudinal axis; andb. detachably connecting the lens assembly to a portion of the base member within the reflector assembly such that the lens assembly is recessed above a substantially horizontal plane extending between the first and second longitudinal side edges and such that the lens assembly is not visible at high viewing angles in a vertical plane normal to the base longitudinal axis. - View Dependent Claims (62, 63, 64, 65, 66, 67)
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Specification