Variable density diffuser for lighting fixtures

Claim 2

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material having upper and lower surfaces and including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete areas with the upper and lower surfaces displaced at continuously varying distances from the plane defined by said edge region and having a thickness which varies inversely with the displacement distance from the said plane whereby each of said discrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement of said surfaces from said plane.

Claim 3

The combination according to claim 1 where in, the ratio of the displacement distance of said discrete areas from said plane compared with the distances across said discrete area has a ratio greater than of 1:1.

Claim 4

The combination in accordance with claim 1 wherein each of said discrete areas is bounded by rib portions, said rib portions constitute an equilateral grid and said discrete area therebetween comprises a substantially semi spherical bubble.

Claim 5

The combination in accordance with claim 3 wherEin one side of said diffuser is coated with opaque material to a thickness in the rib regions which is sufficient to render said rib regions opaque and of continuously varying thickness in the region displaced from the plane of said ribs wherein the central most portion of each discrete area is free of opaque material coating and constitutes a light transmitting region.

Claim 6

The combination in accordance with claim 4 wherein said opaque material is metal and said diffuser presents a metallic grid appearance when viewed at or near the plane of said ribs and the appearance of light transmitting regions surrounded by metallic boundary regions with continuously variable light transmission transition therebetween.

Claim 7

The combination in accordance with claim 5 wherein said opaque metal materail is the product of metal deposition from a source of metal particles directed at said diffuser substantially parallel to the plane defined by said edge regions.

Claim 8

A diffuser for fluorescent luminaires comrising a unitary sheet of formed plastic material including an edge region defining a plane constituting the radiating surface of said luminaire, said diffuser having edge region for mounting said diffuser in a luminaire and at least one truncated recess having a substantially planar end region displaced from said edge region and angular side walls, said angular side walls being of continuously variable thickness ranging from the thickest portion adjacent to said edge region and a thinnest region adjacent to said end region, said end region having a thickness in the order of less than one half the thickness of said edge region, said diffuser being of translucent material whereby the light transmission property of said diffuser varies continuously from said edge region to said end region.

Claim 9

A diffuser for fluorescent luminaires comrising a unitary sheet of formed plastic material including an edge region defining a plane constituting the radiating surface of said luminaire, said diffuser having edge region for mounting said diffuser in a luminaire and at least one truncated recess having a substantially planar end region displaced from said edge region and angular side walls, said angular side walls being of continuously variable thickness ranging from the thickest portion adjacent to said edge region and a thinnest region adjacent to said end region, said end region having a thickness in the order of less than one half the thickness of said edge region, said diffuser being of translucent material whereby the light transmission property of said diffuser varies continuously from said edge region to said end region.

Claim 10

The combination in accordance with claim 7 wherein said diffuser includes a plurality of truncated pyramidal recesses extending transverse to the direction elongated lamps associated with said diffuser, said recesses separated by integral ribs extending substantially to the said plane of radiating surface at said diffuser.

Claim 11

A fluorescent luminaire comprising an elongated housing having an open face for the radiation of light from a fluorescent lamp therein, means mounting a fluorescent lamp in said housing, a diffuser secured to said housing substantially closing said face of said housing, said diffuser comprising a single sheet of translucent material having a planar edge portion for mounting to said housing and at least one portion displaced from the plane of said edge portion extending into said housing, said at least one displaced portion is of variable thickness with the greatest thickness in the region of the edge portion and constitutes an elongated recess paralleling the axis of a fluorescent lamp in said housing and asymmetrical with respect to a plane transverse to the axis of such fluorescent lamp.

Claim 12

A fluorescent luminaire comprising an elongated housing having an open face for the radiation of light from a fluorescent lamp therein, means mounting a fluorescent lamp in said housing, a diffuser secured to said housing substantially closing said face of said housing, said diffuser comprising a single sheet of translucent material having a planar edge portion for mounting to said housing and at least one portion displaced from the plane of said edge portion extending into said housing, said at least one displaced portion is of variable thickness with the greatest thickness in the region of the edge portion and constitutes an elongated recess paralleling the axis of a fluorescent lamp in said housing and asymmetrical with respect to a plane transverse to the axis of such fluorescent lamp.

Claim 13

The combination in accordance with claim 9 wherein said at least one displaced portion is of continuous variable thickness and light transmissibility with the thinnest region and greatest transmissibility in the region closest to the axis of the fluorescent lamp.

Claim 14

The combination in accordance with claim 9 wherein said at least one displaced portion has a continuous curve cross-section.

Claim 15

The combination in accordance with claim 11 wherein said at least one displaced portion includes a convex curved portion and a concave curved portion to one side of the fluorescent lamp.

Claim 16

The combination in accordance with claim 12 wherein said convex portion constitutes a light transmitting region from the fluorescent lamp to the exterior of said housing and said concave portion constitutes primarily a reflective region for light emanating from said convex portion.

Claim 17

The combination in accordance with claim 9 wherein said housing includes means for mounting a plurality of fluorescent lamps in generally parallel relationship and said diffuser incLudes a plurality of displaced portions one for each fluorescent lamp and asymmetrical with respect to a plane passing through the axis of each respective fluorescent lamp, said displaced portions each including a first portion adjacent to its respective lamp constituting primarily a light transmitting region and a second portion to one side of said first portion constituting primarily a reflector for light emitted from said first portion.

Claim 18

The combination in accordance with claim 14 wherein said first portion associated with each respective fluorescent lamp includes a generally convex curved region adjacent to its respective fluorescent lamp and said second portion includes a generally concave region each when viewed from the exterior of said housing.

Claim 19

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete areas displaced at continuously varying distances from the plane defined by said edge region and having a thickness which varies inversely with the distance from the said plane whereby each of said descrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement from said plane, said diffuser being elongated to approximate the length of a fluorescent lamp to be used therewith, said displace discrete areas extending transverse to the length of said sheet thereby defining a plurality of displaced recessed areas separated by ribs of undisplaced material.

Claim 20

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete areas displaced at continuously varying distances from the plane defined by said edge region and having a thickness which varies inversely with the distance from the said plane whereby each of said descrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement from said plane, said diffuser being elongated to approximate the length of a fluorescent lamp to be used therewith, said displace discrete areas extending transverse to the length of said sheet thereby defining a plurality of displaced recessed areas separated by ribs of undisplaced material.

Claim 21

The combination in accordance with claim 16 wherein said ribs extend transverse to the length of said diffuser constituting primarily reflectors for light transmitted through said displaced areas and diffusers of light transmitted through said ribs.

Claim 22

The combination in accordance with claim 16 wherein said ribs extend longitudinally with respect to length of said diffuser.

Claim 23

A diffuser for fluorescent luminaires comprising a single sheet of translucent plastic material including an edge region generally defining a plane and a plurality descrete areas having the body of the material displaced from said plane in a direction toward its associated fluorescent lamp, said discrete areas separated by virtually undisplaced boundary regions constituting ribs, said translucent plastic material having a variable thickness ranging from a maximum in said ribs and a minimum at the greatest displacement from said plane, whereby each of said discrete areas has continuously variable light transmission efficiency and continuously variable light diffusion properties, ranging from a maximum of diffusion with a minimum of transmission of light, both from the lamps and the interior reflecting surfaces of the luminaire, in the regions at or near the plane of radiating of the luminaire, to a minimum of diffusion with a maximum of transmission in the regions of greatest displacement from said plane, the diffuser thereby providing most control over the direct and internally reflected light from the luminaire at high angles from nadir, and the least control near nadir.

Claim 24

A diffuser for fluorescent luminaires comprising a single sheet of translucent plastic material including an edge region generally defining a plane and a plurality descrete areas having the body of the material displaced from said plane in a direction toward its associated fluorescent lamp, said discrete areas separated by virtually undisplaced boundary regions constituting ribs, said translucent plastic material having a variable thickness ranging from a maximum in said ribs and a minimum at the greatest displacement from said plane, whereby each of said discrete areas has continuously variable light transmission efficiency and continuously variable light diffusion properties, ranging from a maximum of diffusion with a minimum of transmission of light, both from the lamps and the interior reflecting surfaces of the luminaire, in the regions at or near the plane of radiating of the luminaire, to a minimum of diffusion with a maximum of transmission in the regions of greatest displacement from said plane, the diffuser thereby providing most control over the direct and internally reflected light from the luminaire at high angles from nadir, and the least control near nadir.

Claim 25

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete areas stretched and displaced from the plane defined by said edge region and having a thickness which varies inversely with the distance from the said plane whereby each of said discrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement from said plane.

Claim 26

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete areas stretched and displaced from the plane defined by said edge region and having a thickness which varies inversely with the distance from the said plane whereby each of said discrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement from said plane.

Claim 27

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete vacuum formed areas displaced from the plane defined by said edge region and having a thickness which varies inversely with the distance from the said plane whereby each of said discrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement from said plane.

Claim 28

A diffuser for fluorescent luminaires comprising a unitary sheet of translucent material including an edge region defining a plane of radiating surface of the luminaire, said diffuser including a plurality of discrete vacuum formed areas displaced from the plane defined by said edge region and having a thickness which varies inversely with the distance from the said plane whereby each of said discrete areas has a continuously variable light transmission property ranging from minimum transmissivity on the region of said plane and maximum transmissivity in the region of greater displacement from said plane.