Lensed indirect luminaire having improved light distribution control

• US 4,644,454 A
• Filed: 12/28/1984
• Issued: 02/17/1987
• Est. Priority Date: 12/28/1984
• Status: Expired due to Fees

• Current Assignee: Herst Lighting Company
• Original Assignee: Peerless Lighting Corp (Alsco Incorporated)
• Inventors: Ngai, Peter Y. Y., Herst, Douglas J.
• Primary Examiner(s): Feinberg, Craig R.
• Application Number:
  US06/687,474
• Time in Patent Office: 781 Days
• Field of Search: 362/217, 362/223-225, 362/235, 362/236, 362/242, 362/244, 362/257, 362/260, 362/268, 362/290, 362/292, 362/311, 362/317, 362/326, 362/331, 362/332, 362/339, 362/340 , 362/351, 362/355, 362/361, 362/362, 362/367
• US Class Current: 362/224
• CPC Class Codes: F21V 5/02 of prismatic shape F21V5/04 takes precedence
• CPC Class Codes: F21V 7/0008 providing for indirect lighting
• CPC Class Codes: F21Y 2103/00 Elongate light sources, e.g. fluorescent tubes
• CPC Class Codes: F21Y 2113/00 Combination of light sources

Abstract

An elongated indirect luminaire is provided with two separate lens elements in the form of a primary trough-shaped lens cover supported over the luminaire'"'"'s light source and at least one secondary lens strip supported laterally of the primary lens cover. A prismatic surface is formed on the lens cover for directing a portion of the available source light to the secondary lens strip; the secondary lens in turn has a prismatic surface designed for redirecting the light in a desired controlled fashion. The laterally placed secondary lens provides added control to the light distribution in the lateral regions of the luminaire near the luminaire'"'"'s operative horizontal plane, and, in the illustrated embodiment, is designed to slightly boost the light in the lateral regions near the horizontal plane in a manner that provides improved control over the luminance of the secondary lens at viewing angles near the horizontal plane of the fixture. Such optical control provides a visible low brightness secondary lens in a fixture mounted at or near eye level.

Claims

1. A lensed indirect luminaire having improved light distribution control comprising

a light source,

a housing for supporting said light source, said housing extending in a horizontal plane of the luminaire and being open generally upwardly and laterally of the luminaire to allow light from said light source to be directed generally upwardly from said luminaire and laterally near and above the horizontal plane of the luminaire,

a light transmitting primary lens means having along at least one of its sides a prismatic lens portion, said primary lens means being supported by said housing in spaced relation to said light source so as to receive at least a portion of said laterally directed light, and

an elongated light transmitting secondary lens means positioned substantially normal to said plane, and having a prismatic lens portion, said secondary lens means being supported by said housing outwardly of and in lateral spaced relation to said primary lens means on the side of said prismatic lens portion of said primary lens,

the linear prismatic surface portion of said primary lens means being formed to transmit therethrough and redirect substantially all light received from said light source in a direction towards said secondary lens means and the linear prismatic surface portion of said secondary lens means being formed to transmit therethrough and further redirect substantially all light from said primary lens means and whereby said first and second lens means effect directing the source light transmitted therethrough generally laterally of said luminaire to increasingly focus the source light as it passes through each of said lens means for controlling source light directionality near the plane of the housing.

2. The indirect luminaire of claim 1 wherein said housing includes an opaque bottom wall, and said primary lens means is in a form of a lens cover supported above said opaque bottom wall so as to at least partially cover said light source.

3. A lensed indirect luminaire having improved light distribution control comprising

a light source,

a linear, elongated housing for supporting said light source, said housing having an opaque bottom wall extending in a horizontal plane of the luminaire and being generally open upwardly and laterally of the luminaire to allow light from said light source to be directed generally upwardly from said luminaire and laterally near and above the horizontal plane of the luminaire,

a light transmitting elongated primary lens cover supported above the opaque wall of said housing so as to at least partially cover said light source, said primary lens means having along at least one of its sides a linear lateral prismatic lens portion for receiving generally laterally directed light from said light source, and

a light transmitting outer, linear secondary lens strip supported by and positioned substantially normal to said housing bottom wall laterally of and in spaced relation to said lens cover on the side of said linear prismatic lens portion of side primary lens,

the lateral prismatic portion of said lens cover being formed to transmit and redirect substantially all light received from said light source in the direction of said secondary lens strip and said secondary lens strip being formed to transmit and further redirect light from the lateral prismatic portions of said lens cover and whereby said first and second lens means effect directing the source light transmitted therethrough generally laterally of said luminaire to increasingly focus the source light as it passes through each of said lens cover and lens strip for controlling source light directionality near the horizontal plane of the housing.

4. The indirect luminaire of claim 3 wherein said secondary lens strip is, substantially throughout its length, mounted in a uniform spaced relation to said primary lens.

5. The indirect luminaire of claim 4 wherein said secondary lens strip extends substantially upwardly from the opaque bottom wall of said housing to approximately a height same as that of said lens cover.

6. The indirect luminaire of claim 5 wherein said primary lens cover has a widespread distribution pattern and said secondary lens strip has a prismatic light bending surface formed to bend, on a more upwardly path, light rays received from substantially all points of said primary lens cover whereby the secondary lens strip acts to boost upwardly the widespread light distribution pattern of said primary lens cover in lateral regions of said light distribution pattern.

7. A lensed indirect luminaire having improved light distribution control in operative regions near a horizontal plane of the luminaire comprising

an elongated light source including at least one fluorescent lamp,

an elongated linear housing having an opaque bottom wall and being generally open upwardly and laterally of the luminaire to allow light from said light source to be directed generally upwardly from said luminaire and laterally near and above the horizontal plane of the luminaire,

a primary lens means in a form of an elongated troughshaped lens cover removably supported by the opaque bottom wall of said housing so as to cover said light source, said lens cover having a linear lateral prismatic lens portion extending upwardly from at least one side of said lens cover for receiving generally laterally directed light from said light source, and

at least one outer linear, elongated secondary lens strip removably supported by and positioned substantially normal to said housing bottom wall laterally of and along its length in uniform spaced relation to said primary lens means on the side of said linear prismatic lens portion of said primary lens, the lateral prismatic portion of said primary lens cover being formed to transmit and redirect substantially all light received from said light source in an upward widespread distribution pattern and said secondary lens strip being formed to transmit and redirect, on a more upwardly path, substantially all light rays received from said lens cover whereby the secondary lens strip acts to boost upwardly the upwardly widespread light disbribution pattern of said primary lens means in lateral regions of said distribution pattern.

8. The indirect luminaire of claim 7 wherein a secondary lens strip is removably mounted to only a front side of said luminaire and wherein the lens cover is foreshortened toward a back side of said luminaire and is supported on said back side by an opaque rear wall of said housing.

9. The indirect luminaire of claim 7 wherein said cover lens includes a top prismatic portion formed to spread upwardly directed light passing therethrough.