Troffer luminaire system having total internal reflection lens
09765944 · 2017-09-19
Assignee
Inventors
Cpc classification
F21Y2103/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V14/06
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S8/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/0091
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2113/17
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21Y2115/10
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V5/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S4/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V5/043
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F21V5/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V5/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V5/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S4/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21V7/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F21S4/28
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A troffer luminaire that includes a plurality of solid state lighting devices, and a first lens and a second lens having total internal reflection (TIR) to collect light from the lighting devices and produce a light output with good luminance uniformity; and to control the distribution profile of the light output through the first lens and the second lens as desired for particular lighting applications.
Claims
1. A lighting system comprising: a lighting strip including a plurality of light sources; a first lens and a second lens each being in optical communication with the plurality of light sources such that substantially all of the light emitted by the plurality of light sources is transmitted through the first and second lenses; wherein the first and second lenses are disposed adjacent to the lighting strip at a position characterized by (i) a top of the first lens and a top of the second lens not touching one another and by (ii) the top of the first lens and the top of the second lens each having a distance of separation relative to the lighting strip; and wherein the top of the first lens and the top of the second lens are disposed less than about 0.5 inch apart.
2. The lighting system according to claim 1, wherein the lighting system further includes a troffer housing the plurality of light sources.
3. The lighting system according to claim 1, further comprising a reflector being in optical communication with the plurality of light sources.
4. The lighting system according to claim 1, further comprising a diffuser being in optical communication with the plurality of light sources.
5. The lighting system according to claim 4, wherein the diffuser is a light shaping diffuser.
6. The lighting system according to claim 1, wherein the first lens and the second lens each include a semi-cylindrical lens.
7. The lighting system according to claim 1, wherein the first lens and second lens are formed of an acrylic rod.
8. A troffer luminaire system, comprising: a plurality of light emitting diodes; and a first lens and a second, each being in optical communication with the plurality of light emitting diodes, wherein the first lens and the second lens are disposed adjacent to the plurality of light emitting diodes in a position providing total internal reflection such that substantially all of the light emitted by the plurality of light emitting diodes is transmitted through the first and second lenses; wherein the position is characterized by (i) a top of the first lens and a top of the second lens not touching one another and by (ii) the top of the first lens and the top of the second lens each having a distance of separation from the plurality of light emitting diodes; and wherein the top of the first lens and the top of the second lens are disposed less than about 0.5 inch apart.
9. The troffer luminaire system according to claim 8, wherein the position is further characterized by the first and second lenses being disposed at an angle with respect to one another.
10. The troffer luminaire system according to claim 8, further comprising a reflector in optical communication with the plurality of light emitting diodes.
11. The troffer luminaire system according to claim 10, further comprising a diffuser in optical communication with the plurality of light emitting diodes.
12. A lighting method, comprising: mounting a linear array of light sources in a fixture housing for emitting light; disposing a first lens and a second lens operatively coupled to at least one light source of the light sources and being semi-cylindrical and having total internal reflection in optical communication with the light sources such that substantially all of the light emitted by the light sources is transmitted through the first lens and the second lens and onto an item or area to be illuminated; and adjusting a position of the first lens and the second lens to direct transmission of light to be reflected internally, and change the distribution of light output by the first lens and the second lens.
13. The lighting method according to claim 12, wherein the light is transmitted through the first lens and the second lens are based on at least one from the group consisting of the distance of the first lens or the second lens from the lighting source, the distance of the first lens from the second lens, an angle of the first lens or the second lens with respect to an optical axis of the lighting source, and the distance of a surface of the lighting source from the top of the fixture housing.
14. The lighting method according to claim 12, wherein the light sources are light emitting diodes.
Description
IV. BRIEF DESCRIPTION OF THE DRAWINGS
(1) The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present invention and, together with the description, further serve to explain the principles of the invention and to enable a person skilled in the relevant art(s) to make and use the invention.
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(9) The drawings are only for purposes of illustrating preferred embodiments and are not to be construed as limiting the disclosure. Given the following enabling description of the drawings, the novel aspects of the present disclosure should become evident to a person of ordinary skill in the art.
V. DETAILED DESCRIPTION OF EMBODIMENTS OF THE PRESENT INVENTION
(10) The following detailed description is merely exemplary in nature and is not intended to limit the applications and uses disclosed herein. Further, there is no intent to be bound by any theory presented in the preceding background or summary, or the following detailed description. Those skilled in the art with access to the teachings provided herein will recognize additional modifications, applications, and embodiments within the scope thereof and additional fields in which the invention would be of significant utility.
(11) While embodiments of the present invention are described herein primarily in connection with LEDs, the concepts are also applicable to other types of lighting devices including solid state lighting devices. Solid state lighting devices include, for example, LEDs, organic light emitting diodes (OLEDs), semiconductor laser diodes, and the like. Similarly, while solid state lighting devices are illustrated as examples herein, the techniques and apparatuses disclosed herein are readily applied to other types of light sources, such as incandescent, halogen, other spotlight sources, and the like.
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(13) Each of the LEDs 112 a-n of the LED array 112, are mounted and interconnected within a printed circuit board (PCB) 114 to facilitate application of electrical power to the array. For purposes of illustration only, and not limitation,
(14) Referring back to
(15) The lighting strip 110 and lenses 120a/b form a light transmission unit configurable to transmit substantially all of the light output from the lighting strip 110 onto an area to be illuminated. Emissive faces of the LEDs 112a-n are preferably oriented in a direct illumination configuration, i.e. facing downward with respect to the elongated lighting strip 110. The lenses 120a/b are arranged in a manner (symmetric or asymmetric) such that light output from one region of the LEDs 112a-n, e.g., a central region, is redirected to another region, e.g., off axis. By varying one or more of: (i) the distance of the lenses 120a/b from the LEDs 112a-n, (ii) the distance of the lens 120a from the lens 120b, (iii) an angle of the lenses 120a/b with respect to an optical axis of the LEDs 112a-n, and (iv) the distance of a surface of the LED 112a from the top of the troffer 125, light can be distributed in an optically efficient manner with good troffer luminance uniformity.
(16) The LEDs 112a-n within the LED array 112 are interconnected in groups or clusters to produce a warm white light output when properly mixed. Various known techniques may be used to produce white light. For example, the LEDs 112a-n may be compatible with a blue-shifted-yellow plus red (BSY+R) LED lighting technique, well known by those of skill in the art, using a combination of BSY LEDs and red LEDs (R). BSY refers to the color produced when a fraction of blue LED light is wavelength-converted by a yellow phosphor coating. The resulting light output is a yellow-green color in addition to the blue source light. BSY light and red light when properly mixed produce a warm white light. Therefore, the BSY+R LED lighting scheme would be suitable for producing a warm white light appropriate for use with the troffer luminaire system 100.
(17) By way of further example, the LEDs 112a-n may also be compatible with another exemplary known technique includes using a red, green and blue (RGB) LED scheme. The RGB LED scheme may be used to generate various light colors, including white light appropriate for use with the troffer luminaire system 100. While the BSY+R and RGB lighting schemes have been discussed herein, they are provided merely as examples. Thus, it should be understood that other LED lighting schemes would be within the spirit and scope of the present invention and can be used to generate a desired output light color.
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(19) As illustrated in
(20) Dimensions D, θ, and x, along with y define the light distribution of the assembly 100. As D and θ increase, the distribution of light spreads further away, i.e., over a wider area. As D and θ decrease, the distribution of light focuses over a more narrow area. As x increases, the amount of light from the LEDs 112a-n that is coupled into the lenses 120a/b decreases, i.e., a smaller fraction of the angular distribution of the light is influenced by the lenses 120 a/b). This decrease in the fraction of light coupled into the lenses 120a/b effects the luminaire light output distribution. It follows, as x decreases, the amount of light from LEDs 112a-n that is coupled into the lenses 120a/b increases and a larger fraction of the angular distribution of the light is influenced by the lenses 120 a/b. In at least some embodiments, as y increases, more light is reflected by reflector (not shown). An exemplary preferred distance x for optimal efficiency is approximately 1 inch or less. It is noted that the top of the lenses 120a/b adjacent the elongated lighting strip 110 are positioned closely together, e.g., less than approximately 0.5 inches apart, but do not touch in order to help with heat dissipation.
(21) Further, the individual LEDs 112a-n should not be visible when viewed from directly below the system 100, i.e., the system 100 should have exceptional Nadir luminance. At a distance of approximately 0.5 inches of separation between the top of the lenses 120a/b and an x value of approximately 1 inch or less, substantially all the light emitted by the elongated lighting strip 110, i.e., 85% to 95% or more, is totally internally reflected through the lenses 120a/b. It is noted that while a symmetric separation of lenses 120a/b is shown, other embodiments are envisioned that include asymmetric separation of lenses 120a/b, asymmetric positioning of lenses 120a/b, i.e., an asymmetric angle with respect to a vertical axis, and/or an asymmetric number of lenses 120a/b without departing from the disclosure. Further, multiple lenses 120 may also be used to flexibly and predictably control the distribution of light without departing from the disclosure.
(22) As illustrated in the ray tracing model of
(23) The components of the troffer luminaire system 100 may be flexibly arranged in a variety of configurations in order to produce numerous desired light distribution profiles.
(24) The polar candela diagram, e.g., diagram 250, graphically illustrates the output light intensity at specific directions with respect to Nadir, i.e., straight down. Intensity is on the vertical axis (downward) and radial lines indicate elevation angles in 10 degree increments. The luminous intensity, measured in candela (cd), indicates the amount of light produced in a specific direction. The luminous intensity is graphically compiled into polar formatted charts that indicate the intensity of light at each angle away from 0 degree lamp axis or Nadir.
(25) The light measurement data, shown, for example, in Tables 1 and 2 below, lists various measurements related to the output light. These measurements include, for example, measured flux, light output ratio of luminaire (LORL), downward flux fraction (DFF), lamp factor, and the like. The measured flux or luminous flux, measured in lumens (lm), indicates the total amount of light produced by a source without regard to direction. The LORL provides an indication of the loss of light energy, both inside and by transmission through light fittings. As loss of light energy decreases, the LORL increases. Higher LORL indicate more efficient systems. LORLs in the range of 80% to 85% are considered optically efficient. LORLs above 85% are considered highly optically efficient. The DFF indicates the percentage of light that is directed down versus up. The lamp factor provides photometric information related to a particular fixture.
(26) Illuminance, measured in lux (1×), provides the measure of the quantity of light that arrives at a surface. Three factors that affect illuminance include the intensity of the luminaire in the direction of the surface, the distance from the luminaire to the surface, and the angle of incidence of the arriving light. Although illuminance cannot be detected by the human eye, it is a common criterion used in specifying designs. Luminance, measured in candelas per square meter (cd/m2), indicates the quantity of light that leaves a surface and is what the human eye perceives. Luminance indicates more about the quality and comfort of a design than illuminance alone. The cutoff angle of a luminaire indicates the angle between the vertical axis (or Nadir) and the line of sight when the brightness of the source or its reflected image is no longer visible. The cutoff angle is the controlling factor for visual comfort in a lighting system.
(27) The Nadir luminance indicates the quality and uniformity of the output light when viewed from directly below the lighting source. Preferred Nadir luminance is comfortable and pleasing to the eye, and shows no individual LEDs or unblended light.
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(29) As illustrated in
(30) Table 1 below illustrates exemplary light measurement data of the luminaire system 200. The light measurement data shows a LORL of greater than 89% which indicates high optical efficiency, and a DFF of greater than 99%. The Nadir luminance of the luminaire system 200 has exceptional quality and uniformity of the output light.
(31) TABLE-US-00001 TABLE 1 Measured flux: 3737.7 1 m Light output ratio luminaire (LORL): 89.42% Downward flux fraction (OFF): 99.92% UTE C71 - 121 photometric: 0.89 F
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(33) TABLE-US-00002 TABLE 2 Measured flux: 3849.74 1 m Light output ratio luminaire (LORL): 92.1% Downward flux fraction (OFF): 99.95% UTE C71 - 121 photometric: 0.92 E
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(35) The alternative embodiment according to
(36) The alternative embodiment according to
(37) The alternative embodiment according to
(38) The alternative embodiment according to
(39) The various embodiments of the troffer luminaire system, as discussed above with respect to
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(41) Alternative embodiments, examples, and modifications which would still be encompassed by the disclosure may be made by those skilled in the art, particularly in light of the foregoing teachings. Further, it should be understood that the terminology used to describe the disclosure is intended to be in the nature of words of description rather than of limitation.
(42) Those skilled in the art will also appreciate that various adaptations and modifications of the preferred and alternative embodiments described above can be configured without departing from the scope and spirit of the disclosure. Therefore, it is to be understood that, within the scope of the appended claims, the disclosure may be practiced other than as specifically described herein.