CA3096069A1 - Prismatic led module for luminaire - Google Patents

Abstract

208272-9143-CA01 PRISMATIC LED MODULE FOR LUMINAIRE ABSTRACT OF THE DISCLOSURE An LED module for a luminaire has a downwardly directed heat sink comprising cooling fins that extend rearward from the module's front end and downward from its top wall, which has a top face that abuts the underside of a luminaire carrier plate. A circuit board carrying at least one LED is mounted on the front face, and a prism is mounted to the heat sink over the LED(s). The front (light-emitting) face of the catadioptric prism has several prominent side- by-side sections which emit beam patterns that diverge laterally and overlap in a central region. A prominent full-width upper section on the front face emits a primarily downwardly directed beam pattern to help fill in dark spots. Date Recue/Date Received 2020-10-13

Description

PRISMATIC LED MODULE FOR LUMINAIRE
This application is a division of application no. 2,804,118 that was filed in Canada on January 25, 2013.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. provisional patent application No. 61/591,619, filed January 27, 2012.
FIELD OF THE INVENTION

[0002] The invention relates to the field of lighting and concerns luminaires utilizing light emitting diodes (LEDs) for illuminating an area. More particularly, the invention concerns LED modules that can be arrayed in a luminaire to provide a desired level, direction and pattern of illumination.
BACKGROUND

[0003] Commonly owned U.S. Patent No. 8,342,709, which may be referred to for further details, discloses various arrays of LED modules that snap into relatively large rectangular openings in a luminaire carrier plate. A portion of each module's heat sink extends into the luminaire housing above the carrier plate, and each module has a four-sided reflector that shapes and directs the light emitted by a row of LEDs mounted on a circuit board.
SUMMARY OF THE INVENTION

[0004] The LED module of the present invention has a downwardly directed heat sink and is adapted for installation on the underside of a luminaire carrier plate. The heat sink comprises a front end having a front face, a top wall extending rearward from the front end, and a plurality of cooling fins extending rearward from the front end and downward from the top wall. The top wall has a top face for abutting the underside of the luminaire carrier plate. A
circuit board carrying at least one LED is mounted on the front face, and a prism is mounted to the heat sink over the LED(s). The top face preferably is disposed at an acute angle to the front face, and the cooling fins preferably taper in height from the front end rearward.

Date Recue/Date Received 2020-10-13

[0005] Another aspect of the invention is a catadioptric prism per se for shaping and directing light emitted by an even number of aligned, laterally spaced LEDs. The prism has a transparent body with a fore-and-aft medial vertical plane and comprises a rear light-receiving face, a front light-emitting face, a top face, a bottom face and two side faces. The front face has several prominent sections, as follows. A lower section on each side of the medial vertical plane has a substantially vertical front, and substantially vertical curved sides that merge with the front. A middle section on each side of the medial vertical plane and above the lower section is wider than it is high and has a substantially horizontal rounded face with rounded ends that merge with the rounded face. An upper section, which is above both middle sections, has a downwardly and forwardly slanted surface. The rear face of the prism has a convex cradle section on each side of the medial vertical plane. Each cradle section has at least one pocket behind the middle section of the front face for cradling an LED; and the pockets are symmetrically disposed on opposite sides of the medial vertical plane. The prism preferably is bilaterally symmetrical about the medial vertical plane.
[0005a] Still another aspect of the invention is a luminaire including a housing and a plurality of lighting modules. The housing has a top portion and a bottom portion, with the bottom portion including a carrier plate. The plurality of lighting modules each includes a metallic heat sink with a flat upper wall abutting the carrier plate, a front face adjacent the upper wall and two or more parallel cooling fins disposed below and perpendicular to the flat upper wall and the front face. The flat upper wall of the plurality of lighting modules is disposed at an acute angle to the front face.

Date Recue/Date Received 2020-10-13 BRIEF DESCRIPTION OF THE DRAWING

[0006] Preferred embodiments of the disclosed invention, including the best mode for carrying out the invention, are described in detail below, purely by way of example, with reference to the accompanying drawing figures, in which:

[0007] Fig. 1 is a perspective view of an LED module according to the invention, taken from the front and left side thereof;

[0008] Fig. 2 is a side elevational view thereof;

[0009] Fig. 3 is a bottom plan view thereof;

[0010] Fig. 4 is an exploded view thereof;

[0011] Fig. 5 is a perspective view of the heat sink portion of the module of Fig. 1 taken from the front, top and left side;

[0012] Fig. 6 is a perspective view thereof taken from the front, bottom and left side;
Intentionally left blank.
2a Date Recue/Date Received 2020-10-13

[0013] Fig. 7 is a bottom perspective view of a luminaire having a particular array of LED modules according to Figs. 1-4 installed therein;

[0014] Fig. 8 is a bottom plan view thereof;

[0015] Figs. 9 through 13 are schematic illustrations of five different light beam patterns producible by five different arrays of LED modules according to the invention;

[0016] Fig. 14 is a perspective view of a prism of the invention taken from the front, top and right side thereof;

[0017] Fig. 15 is a perspective view thereof taken from the front, bottom and right side;

[0018] Fig. 16 is a perspective view thereof taken from the rear, top and right side;

[0019] Fig. 17 is a perspective view thereof taken from the rear, bottom and right side;

[0020] Fig. 18 is a top plan view thereof;

[0021] Fig. 19 is a front elevational view thereof;

[0022] Fig. 20 is a bottom plan view thereof;

[0023] Fig. 21 is a right-side elevational view thereof;

[0024] Fig. 22 is a left-side elevational view thereof;

[0025] Fig. 23 is a rear elevational view thereof;

[0026] Fig. 24 is a cross-sectional view thereof taken along line 24-24 in Fig.
23;

[0027] Fig. 25 is a cross-sectional view thereof taken along line 25-25 in Fig.
23;

[0028] Fig. 26 is a cross-sectional view thereof taken along line 26-26 in Fig.
23;

[0029] Fig. 27 is a left-side elevational view thereof showing LED light ray traces reflecting, refracting and emanating from the left half thereof; and

[0030] Fig. 28 is a top plan view thereof showing LED light ray traces reflecting, refracting and emanating from the right half thereof.

Date Recue/Date Received 2020-10-13 DETAILED DESCRIPTION OF THE INVENTION

[0031] As used in this application, including the claims, terms such as "front," "rear," "side," "top," "bottom," "above," "below," "upward,"
"downward,"
"lateral," "vertical" and "horizontal" are used in a relative sense to facilitate the description of the invention, and are not intended to limit the invention to any particular position or orientation except when clearly describing its orientation in an installed, operational position.

[0032] Referring to Figs. 1-6, an exemplary sealed LED module 8 according to the invention comprises an optically clear prism 10 secured by two screws 12 to the front of a wedge-shaped heat sink 14 over a printed circuit board (PCB) 16, which carries four aligned, laterally spaced LEDs 18 symmetrically arranged in two pairs. A thermal paste or other conventional heat transfer medium preferably is interposed between PCB 16 and the front face of heat sink 14. A rectangular gasket 13 is disposed between prism 10 and heat sink 14 to surround and seal PCB 16 from the environment. A hole 20 in PCB 16 and holes 22, 24 in heat sink 14 enable routing of power conductors (not shown) through the heat sink to the PCB.

[0033] Heat sink 14 preferably is made of anodized, die cast aluminum and has a series of parallel vertical cooling fins 26 on its underside. The penultimate cooling fin on each side is shortened to make room for a mounting hole 28 in the top wall 29 of the heat sink, which accommodates a mounting screw (not shown) from below for attachment to the carrier plate P of a luminaire (see, e.g., Figs. 7 and 8). A locating stud 30, which projects upward from the top wall 29, is adapted to register with a mating feature on the carrier plate to ensure proper positioning of the module 8 against the underside of the carrier plate. A rectangular central upper gasket (not shown) forms a seal against the carrier plate around hole 24.

[0034] The array of LED modules 8 shown in Figs. 7 and 8 comprises a center row of six forward-facing modules flanked on each side by twelve modules (in two rows of six modules each) that face obliquely toward the center Date Recue/Date Received 2020-10-13 row. Other arrays of modules may be used to provide desired patterns of illumination. For example, U.S. Patent No. 8,342,709 discloses five exemplary arrays of LED modules mounted to a luminaire carrier plate to produce the five different patterns shown in Figs. 18-22 thereof. Figs. 9-13 herein are substantial reproductions of those figures and show that the same types of patterns can be produced by arrays of modules 8 according to the present invention from a luminaire F projecting a light beam B generally along an optical axis X (the axis corresponding to the maximum candlepower). Those patterns substantially correspond to the beam shapes specified in IES NEMA
regulations as Type I (Fig. 9); Type II (Fig. 10); Type III (Fig. 11); Type IV
(Fig.
12); and Type V (Fig. 13). The module array of Figs. 7 and 8 will produce a Type 3 beam shape.

[0035] Due to the slant of heat sink top wall 29, prism 10 will face obliquely downward when the LED module is mounted to a substantially horizontal luminaire carrier plate. That orientation and the optical characteristics of the prism 10 (described below) will cause the optical axis X to meet a substantially horizontal surface to be illuminated at an angle of approximately 60 to 80 off vertical, preferably about 65 to 70 off vertical as shown in Fig. 27. This generally will be the situation regardless of luminaire mounting height. Fig.

of U.S. Patent No. 8,342,709 schematically illustrates this geometry. As roughly illustrated by the ray traces in Figs. 27 and 28 herein, about 95% of the main beam intensity will be within about a 10 to 12 vertical spread by about a 30 to 40 horizontal spread, and about 5% of the beam intensity will be aimed downward at about 20 to 25 off vertical to help fill dark spots below the luminaire. For the sake of simplicity, Fig. 28 shows the ray traces of only one side of prism 10. The ray traces of the other side of the prism are the mirror image of those shown, with beam overlap in the central region.

[0036] Prism 10 preferably is molded of a UV stabilized, optically clear acrylic thermoplastic material having a refractive index of about 1.49. Other materials may be used instead, for example, glass or polycarbonate. The optical surfaces Date Recue/Date Received 2020-10-13 preferably have a class A polish to maximize internal reflections. Figs. 14-28 show the physical features of the prism, which is bilaterally symmetrical about its fore-and-aft medial vertical plane M (see Figs. 19 and 23) and includes a hollow rectangular mounting base 32 having mounting holes 34 and a peripheral flange 36 that surrounds PCB 16. The light-shaping portions of prism 10, which are integrally formed with base 32, are situated centrally and mostly forward of flange 36 and have a flat bottom 38, flat sides 40 and a flat top 42.

[0037] At the front of prism 10 on each side of the medial vertical plane, at the bottom, is a bulging "breakfront" portion 44 having curved vertical sides and a substantially flat, vertical front face 48. Above breakfront portion 44 is a horizontal "semi-tubular" portion 50 with rounded ends 52 and a rounded face 54, which has a radius of curvature that tightens toward its horizontal center.
Above semi-tubular portion 50 is a horizontal "forehead" bar 56 that spans both sides and has a slightly slanted "brow" portion 58, which gradually transitions to a flat, more slanted "crown" portion 60. At the rear of prism on each side of the medial vertical plane is a convex, horizontally elongated "cradle" portion 62, which has two side-by-side pockets (recesses) 64 separated by a vertical rib 66. Each pocket 64 cradles an LED 18 (see Figs. 2 and 3). As seen in Fig. 27, it is forehead bar 56 that directs the small portion (about 5%) of the beam intensity downward to help fill dark spots below the luminaire.

[0038] While exemplary embodiments have been chosen to illustrate the invention, it will be understood by those skilled in the art that various changes, modifications, additions, and substitutions are possible, without departing from the scope and spirit of the invention.

Date Recue/Date Received 2020-10-13

Claims (5)

WHAT IS CLAIMED IS:

1. A luminaire comprising:
a housing having a top portion and a bottom portion, said bottom portion including a carrier plate;
a plurality of lighting modules each including a metallic heat sink with a flat upper wall abutting said carrier plate, a front face adjacent said upper wall and two or more parallel cooling fins disposed below and perpendicular to said flat upper wall and said front face, wherein said flat upper wall of said plurality of lighting modules is disposed at an acute angle to said front face.

2. The luminaire of claim 1, wherein said heat sink is a single unitary piece.

3. The luminaire of claim 1, wherein said bottom portion includes a single carrier plate.

4. The luminaire of claim 1, wherein said flat upper wall of said plurality of lighting modules has at least one opening for accommodating a fastener to secure the module to said carrier plate of said housing.

5. The luminaire of claim 1, wherein said plurality of lighting modules each includes at least one locating stud for engaging a corresponding recess in said carrier plate.

Date Recue/Date Received 2020-10-13